Note: Descriptions are shown in the official language in which they were submitted.
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INJECTION MOLDED FLOOR TILES WITH DRAINAGE VENTS
BACKGROUND OF THE INVENTION
[0001] Conventional modular injection-molded tiles are known in the art for
laying across upper
surfaces of garage floors, sports surfaces, outdoor surfaces and other
substrates. These tiles
typically are twelve to thirteen inches square and can be manually assembled
and disassembled. A
common feature of these tiles is their ability to be snapped together, with
few or no tools, using
male and female connectors molded into each tile for the purpose.
[0002] Conventional single tiles are molded to be a single, uniform color such
as all-black or all-
red. The consumer typically can choose different tiles in different colors.
The consumer or
contractor will often choose two or more colors for a particular floor, for
assembly into an
aesthetically pleasing pattern. But manufacturing an injection-molded plastic
tile that has two or
more perceptible colors per tile is more difficult and to date no such tile
has been provided that has
proven to be acceptable to the consumer.
[0003] Many conventional modular plastic tiles are easily dislodged from their
positions on the
floor (particularly where wheeled vehicles are driven onto and off of them)
and require a rubber
sheet or the like as a substrate. It would therefore be advantageous to
furnish a floor tile, for
applications in which a large displacing lateral force may be applied to the
tile, and which does not
require a nonslip sheet as a substrate.
[0004] Previous attempts have been made to produce plastic modular tiles that
have cushioning
characteristics. U.S. Patent Application Publication No. US 2009/0031658 Al
discloses modular
athletic floor tiles that have a plurality of premolded rubber inserts which,
after molding, are
physically inserted into receiving holes in a molded plastic substrate. In one
embodiment each
rubber insert has a face that is stands up from the surrounding top floor
surface. The body of each
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rubber insert extends all the way through the plastic substrate or base and
well below its bottom.
The rubber inserts are selectively compressed when an athlete stands on them,
giving a cushioning
effect. But it is believed that the separate molding of these inserts, flash
removal from them and
physical insertion of them into respective receiving holes in the plastic tile
substrate is time-
consumptive and greatly increases the cost of manufacture of the resultant
tile.
100051 A need therefore persists in the industry for modular plastic tiles
which can sustain heavy
loads but have non-slip characteristics, which will be effectively joined
together, which can be
provided in a plurality of colors per tile, and which can be manufactured
quickly and inexpensively.
SUMMARY OF THE INVENTION
100061 According to one aspect of the invention, a modular floor tile is
provided which may be
used to create a flooring surface including a plurality of like tiles. A first
polymer compound is
used to mold a body of the tile. The body has at least one feature overmolded
onto the upper
surface of the body from a second polymer compound which is different from the
first polymer
compound. A second polymer compound gate is disposed to be adjacent a lower
surface of the tile
body and to be remote from the upper surface thereof. The gate communicates to
the upper feature
through a through-hole which extends from the lower surface to the upper
surface. A vent hole,
laterally spaced from the through-hole, extends from the upper surface back to
the lower surface
and is in communication with the upper feature. During the injection of the
second polymer
compound, molten polymer makes its way from the gate, through the through hole
and into the
cavity in which the upper feature will be created. The vent hole permits gas
or other fluid to be
displaced out of the upper feature cavity, thereby obviating or minimizing any
void in the as-
molded upper feature which might otherwise occur. In one embodiment a portion
of the upper pad
extends through the vent hole to be disposed below or protrude onto the lower
surface. Preferably,
the tile has many such pads on its upper surface, and many such support
members downwardly
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,
depending from its lower surface. Groups of these pads and support member
portions may be
molded together in a continuous phase of the second polymer compound.
[0007] The second polymer compound may differ from the first polymer compound
in rigidity,
coefficient of friction, color, or some or all of these, and in one embodiment
the upper feature
constitutes a nonslip pad. In one embodiment a spaced-apart plurality of such
upper features are
formed as connected to one gate, through a plurality of through-holes, with at
least one vent hole
accorded to each of the upper features. In one embodiment the vent hole is
laterally positioned to
be maximally spaced from the through hole and still be within the periphery of
the upper feature. In
one embodiment the periphery of the upper feature is defined by a smoothly
finished crush ring
which prevents flash of the second polymer compound.
[0008] In another aspect of the invention, a modular floor tile of the above
construction further
has at least one lower feature overmolded onto the lower surface of the tile
body from the second
polymer compound. The gate communicates directly with this lower feature by a
path which does
not pass through the body. The lower feature may, for example, be a "skin"
overmolded over a
support member core, the skin and core constituting a support member. A
portion of the second
polymer compound may extend from the upper feature, through the vent hole and
onto the lower
surface of the body, and in such embodiment it is preferred that the lower
feature as-molded be
spaced from such portion. This may be accomplished by forming a crush pad
completely laterally
around such portion and also around the lower feature.
[0009] There may be a plurality of such lower features, all connected to a
single gate. In one
embodiment, groups of upper features and associated lower features all connect
to respective fill
points or gates, with the tile having a plurality of these groups.
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[00101 In a further aspect of the invention, a method of forming a plastic
modular floor tile
includes molding a body of a first thermoplastic polymer compound, and then
overmolding the
body using a second polymer compound that has different characteristics from
the first, such as
differences in rigidity, coefficient of friction and/or color. The step of
overmolding includes the
substeps of positioning a gate adjacent the lower surface of the tile body and
remote from an upper
surface thereof; flowing polymer from the gate through a vent-hole to form an
upper feature on the
upper surface; and displacing a fluid (such as a gas) out of the volume of the
upper feature cavity
through a vent hole extending from the upper surface to the lower surface
thereof, thereby
minimizing or obviating any void which might otherwise appear in the upper
feature as molded.
[0011] In one embodiment, the method further includes flowing the molten
second polymer
compound from the gate, by a path which does not pass through the tile body,
to a lower feature
which is overmolded on the lower surface of the body. The method may also
include the step of
flowing molten second polymer compound through the vent hole such that a
portion thereof
protrudes onto the lower surface of the tile body. In this last instance the
method further preferably
includes spacing such portion from the lower feature as by a crush pad, so
that the flow of polymer
creating the lower feature won't conflict with the flow of polymer creating
the upper feature, and so
that any gas or fluid will be positively displaced from the upper surface
through the vent hole. In
one embodiment, groups of upper and lower features are each formed from
polymer flowing from a
single respective gate or fill point. The method may be used to overmold
nonslip pads on the tile
upper surface and, in one embodiment, to simultaneously overmold support
member nonslip skins
on the lower surface of the tile.
[0012] In a further embodiment, a plurality of elongate drainage vents are
formed in the body of the
tile from its general upper surface to its general lower surface. Where the
tile is injection molded
from at least first and second thermoplastic materials, the drainage vents are
laterally spaced from
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each feature created by overmolding the first-shot body with the second
thermoplastic material. In
those embodiments employing crush rings and/or crush pads to respectively
prevent flash from the
overmolded features, the drainage vents are laterally spaced from the crush
rings and/or crush pads.
In one embodiment, respective ribs laterally surround the overmolded feature
groups. These ribs
project downwardly from the general lower surface of the tile and may be
discontinuous, so as to
permit fluid drained by the vents to pass to the points exterior to the volume
enclosed by the
respective ribs. The drainage vents may be disposed in channels defined by
adjacent ones of these
ribs. The vents may be radiussed at the body upper surface, and/or beveled, to
greatly increase the
surface area thereat, thereby enhancing the vents' capability to collect and
drain fluid.
[0013] In one embodiment, the floor tile is injection molded using a plurality
of spaced-apart
gates. Groups of elongate drainage vents are arranged around respective
gates/fill points, in a
substantially radiant fashion. As so disposed, the impedance of the drainage
vents to polymer flow
will be minimized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] These and further aspects of the invention and their advantages can be
discerned in the
following detailed description, in which like characters denote like parts and
in which:
[0015] FIGURE 1 is an isometric view of four modular floor tiles according to
the invention, as
assembled into a portion of a flooring surface;
[0016] FIGURE 2 is a front isometric view of one of the modular floor tiles
shown in FIGURE 1;
[0017] FIGURE 3 is a back view of the modular floor tile shown in FIGURE 2;
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,
,
[0018] FIGURE 4 is an isometric detail of the back of the floor tile shown in
FIGURE 3,
illustrating a tile body prior to overmolding with a second polymer compound;
[0019] FIGURE 5 is an isometric detail of the same tile region shown in FIGURE
4, shown after
overmolding has been completed;
[0020] FIGURE 6 is a detail of the upper surface of a tile according to the
invention prior to
overmolding, showing flow-through points and crush rings;
[0021] FIGURE 7 is a detail of the same region illustrated in FIGURE 6, shown
after top surface
pads have been overmolded;
[0022] FIGURE 8 is a magnified sectional detail of two adjoining tiles showing
internal structure
of the support members;
[0023] FIGURE 9 is a magnified sectional detail of a tile showing the
relationship of the
overmolded features on the tile's lower and upper surfaces;
[0024] FIGURE 10 is magnified bottom view detail of a tile according to the
invention;
[0025] FIGURE 11 is a magnified sectional view of two tiles being assembled
together;
[0026] FIGURE 12 is a magnified sectional view of two joined tiles taken
through cooperating
loop and latch structure;
[0027] FIGURE 13 is a diagram showing nonlinear interference between a latch
and a loop
according to the invention;
[0028] FIGURE 14 is a schematic flow diagram illustrating steps in a
manufacturing process
according to the invention;
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[0029] FIGURE 15 is an isometric magnified detail view of a corner of a tile
body according to a
second embodiment of the invention, prior to overmolding a peripheral seal
thereon;
[0030] FIGURE 16 is the tile body corner seen in FIGURE 15, after overmolding;
[0031] FIGURE 17 is a magnified sectional detail through a lateral edge of the
tile illustrated in
FIGURE 16;
[0032] FIGURE 18 is a magnified sectional detail showing joined lateral edges
of adjacent tile,
taken through two cooperating peripheral seals;
[0033] FIGURE 19 is a schematic isometric view of a tile according to a third
embodiment of the
invention, wherein a second polymer compound is injected into a gate on an
upper surface of the
tile;
[0034] FIGURE 20 is a top isometric view of a modular floor tile according to
a fourth
embodiment of the invention;
[0035] FIGURE 21 is a magnified sectional view of two tiles according to a
fifth embodiment of
the invention;
[0036] FIGURE 22 is a magnified sectional view of the two tiles shown in
FIGURE 21, taken
through cooperating latch and loop structure; and
[0037] FIGURE 23 is a back view of a modular floor tile according to another
embodiment;
[0038] FIGURE 24 is an isometric detail of the back of the floor tile shown in
FIGURE 23,
illustrating the tile body prior to overmolding with a second polymer
compound;
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,
[0039] FIGURE 25 is an isometric detail of the same tile region shown in
FIGURE 24, shown
after overmolding has been completed;
[0040] FIGURE 26 is a detail of the upper surface of the tile shown in FIGURE
23 prior to
overmolding, showing through-holes, vent holes, and crush rings;
[0041] FIGURE 27 is a magnified sectional detail of the tile shown in FIGURE
23, showing the
relationship of the overmolded features on the tile's upper and lower
surfaces;
[0042] FIGURE 28 is a schematic flow diagram illustrating steps in an
alternative manufacturing
process according to the invention;
[0043] FIGURE 29 is a perspective view of a sixth embodiment of the invention,
incorporating
drainage vents in a two-shot tile;
[0044] FIGURES 30A and 30B are front and rear details, respectively, of the
embodiment shown
in FIGURE 29;
[0045] FIGURE 30C is a sectional view taken substantially along line 30C ¨ 30C
of FIGURE
30A;
[0046] FIGURE 31 is a perspective view of a seventh embodiment of the
invention, incorporating
drainage vents in a one-shot tile;
[0047] FIGURES 32A and 32B are front and rear details, respectively, of the
embodiment shown
in FIGURE 31;
[0048] FIGURE 32C is a sectional view taken substantially along line 32C ¨ 32C
of FIGURE
32A;
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[0049] FIGURE 33 is a plan view of an eighth embodiment of the invention,
featuring drainage
vents substantially radiating from injection mold gate locations;
100501 FIGURES 34A and 34B are front and rear details, respectively, of the
embodiment shown
in FIGURE 33;
[0051] FIGURE 34C is a sectional view taken substantially along line 34C ¨ 34C
of FIGURE
34A;
[0052] FIGURE 35 is a plan view of a ninth embodiment of the invention,
featuring drainage
vents with reinforcing cross ribs;
[0053] FIGURE 36A is a rear detail of the embodiment shown in FIGURE 35;
[0054] FIGURE 36B is a sectional view taken substantially along line 36C ¨ 36C
of FIGURE
368; and
[0055] FIGURE 37 is a schematic block diagram of a method for designing and
manufacturing a
vented floor tile.
DETAILED DESCRIPTION
[0056] Modular floor tiles according to the invention can be used to form a
flooring surface, a
representative portion 100 of which is shown in FIGURE 1. In this illustrated
embodiment, the
flooring surface 100 is made up of tiles 102, including first floor tiles 102A
and second floor tiles
102B, which are identical except as to color. The floor tiles 102A each have a
body 104 injection-
molded from a first polymer compound, preferably comprising a polymer which is
relatively rigid
when solidified and which can be selected from the group consisting of
polyolefins including
polypropylene and high molecular weight polyethylene, rigid thermoplastic
polyurethane (TPU),
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acrylonitrile butadiene styrene (ABS) and rigid polyvinyl chloride (PVC). The
first polymer
compound may further include filler such as talc to aid in achieving surface
flatness, and a pigment.
Floor tiles 102B have bodies 104 which preferably are made of a polymer
compound identical to
that forming bodies 104 of tiles 102A, except possibly for the choice of
pigment or colorant. Each
floor tile 102 preferably has an array of features 106, or raised pads, on its
upper surface 108. The
pads 106, which preferably are spaced apart on the upper surface 108, are
overmolded onto the
upper surface 108 using a second polymer compound, which has different
characteristics from the
first.
100571 The differences between the first and second polymer compounds can
include color and/or
hardness. In one embodiment the second polymer compound, once solidified, is
softer or less rigid
than the first (once solidified), and has a higher coefficient of friction
with respect to most objects
than does the first. In another embodiment the hardness of the first and
second compounds (once
solidified) is about the same, but the colors are distinctly different. In a
third embodiment, the
hardness (once solidified) of the second compound is greater than that of the
first. In a preferred
embodiment, the second polymer compound can be selected from the group
consisting of styrene
ethylene butylene styrene based thermoplastic elastomer (SEBS TPE), other
TPEs, soft TPU, or soft
PVC. Polypropylene as the principal polymer in the first compound, and SEBS
TPE as the
principal polymer in the second polymer, are particularly preferred and have
demonstrated good
adherence to each other.
100581 One aesthetic advantage of the invention is that the first and second
polymers can be
provided in contrasting colors, and that because of the molding techniques
used in the invention,
pads 106 can be colored differently than upper surface 108 yet present a
sharp, commercially
acceptable appearance.
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[0059] A top isometric view of one tile 102 is shown in FIGURE 2. The body 104
of tile 102 is
in main part a substantially horizontal and planar web 200 that has a
plurality of lateral edges 202,
204. Each of the web edges 202, 204 downwardly depends from the upper surface
108 to a lower
surface (not shown in FIGURE 2). In the embodiment illustrated in FIGURE 2,
edges 202, 204 are
orthogonal to surface 108, are planar and are at right angles to each other.
But the tile 102, and the
edges 202, 204 of it, can take other shapes. For example, the tile 102 can be
hexagonal or
triangular, and the edges 202, 204 could be wavy or curved instead of
straight. Instead of edges
202, 204 being planar, as shown, they could be stepped or have tongues and
corresponding grooves
(see FIGURES 15 ¨ 16 for an embodiment in which the lateral edges are
stepped). It is preferred,
however, that the shape and profile of each web edge 202 be complementary to
the shape and
profile of each web edge 204, such that when adjacent tiles are joined
together, edges 202 and 204
will fit together closely.
[0060] The illustrated embodiment has a two-dimensional array of sixty-four
raised pads 106 as
located on a square surface of about twelve inches in length and width.
Alternatively there could be
as few as one pad 106, which preferably would be larger and possibly elongated
and branched
and/or sinuous. It is preferred to have a regular pattern of the pads 106 so
that sub-units of the tile
102 can be trimmed off of it, in a manner to be explained below, and so that
as trimmed the tile 102
will retain an aesthetically pleasing appearance. The illustrated pads 106 are
rounded squares but
could take other shapes such as circles, ovals, hexagons, triangles,
distinctive logos or other shapes.
[0061] The first edges 202 each are equipped with at least one, and preferably
several, latches
206. The second edges 204 each have at least one, and preferably several,
loops 208. It is preferred
that the number of latches 206, distributed in spaced relation along first
edge 202, equal the number
and position of loops 208, which are distributed in like spaced relation along
each second edge 204.
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In the illustrated embodiment the latches 206 are pressed downward and snapped
into loops 208, in
a manner which will be described in further detail below.
[0062] In the bottom view of tile 102 shown in FIGURE 3, there can be seen
sixteen groups 300
of support members 302. According to one aspect of the invention, each support
member 302 is
formed in part by a skin 304 of a relatively soft polymer compound such as
once comprising TPE,
and has a core that is molded as part of the body 104 from a polypropylene-
based compound or
other relatively rigid polymer composition. Some of the support members 302
are annular and take
the shape of squares with empty centers. Other support members 302 in each
group 300 are short
linear segments. The support members will be discussed in further detail
below. Preferably the
general lower surface 306 also has, depending downwardly from it, a plurality
of elongate rigid
support ribs 308 that have no TPE or other soft polymer skin. The support ribs
are integrally
molded with the web 200 of body 104.
[00631 In the illustrated embodiment, the rigid support ribs 308 form partial
outlines of rounded
squares, each one of which contains one of the groups 300 of the support
members 302. The rigid
support ribs 308 are so positioned that one or more of them are not very far
away from any group
300 of support members 302. This permits the rigid support ribs 308 to accept
most of the load of
heavy objects (such as vehicles) imposed on the upper surface 108 of tile 102.
[0064] The elongate ribs 308 also define and delimit linear channels 310, one
set of which are
aligned along a length of the tile 102, and another set of which are at right
angles to these and are
aligned along a width of the tile 102. The channels 310 are disposed between,
rather than through,
the support member groups 300 and (on the upper surface) the pads 106. This
provides the
consumer a trim guide for cutting apart tile 102 in a lengthwise or widthwise
direction, or both, in
predetermined increments such as three inches or twenty-five percent of tile
102's length or width.
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As projected onto the single horizontal plane occupied by web 200, the center
line of each channel
310 will substantially exactly bisect the distance between the centers of
adjacent pads 106 on either
side of the center line. The distance from the center line of the channel 310
to a center of a pad 106
is one-half of the distance from one center of a pad 106 to a next adjacent
pad 106. Since pads 106,
support member groups 300, latches 206 and loops 208 repeat in a regular
pattern, such as on three-
inch centers, and since the pads 106 are exactly twice as far apart from each
other as the closest of
them are to the edge 202 and/or 204 (see FIGURE 2) or a channel 310, the
consumer may use
trimmed tiles on the periphery of the flooring surface to extend the flooring
surface by another
three, six or nine inches, or alternatively 25%, 50%, or 75% of the length or
width of tile 102. The
regular pattern and spacing of raised pads 106 will continue over from
untrimmed tiles onto such
trimmed peripheral tiles without visually noticeable interruption and
therefore the result will be
aesthetically pleasing.
[0065] FIGUREs 4 and 5 are details of the tile lower surface, showing a single
group 300 of
support members 302 before and after a second polymer compound is overmolded
onto the body
104 of the tile 102. In FIGURE 4 there can be seen a plurality of support
member cores 400 which
depend downwardly (in this view, extending toward the top of the paper) from a
general lower
surface 306 of the substantially horizontal web 200 that makes up most of the
tile body 104. The
cores 400 do not downwardly depend as far as the support ribs 308. Ribs 308
are not overmolded.
In the illustrated embodiment there are provided, in each group 300 of support
members 302, four
annular cores 402 and eight cores 404 formed as short linear segments and in
parallel pairs nearby
the annular cores 402. Also seen here is, for this group 300, a crush pad 406
which in use is slightly
lower than the general surface 306 (in this bottom view, pad 406 is slightly
raised relative to general
surface 306). The crush pad 406 is formed to be closely adjacent all of the
support member cores
400 and laterally surrounds all of the cores 400 and the runners 502
connecting the support
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members. The crush pad 406 is finished to have a smooth surface (general lower
surface 306 can
instead be textured) and is used as a shutoff surface to prevent the flashing
of the second polymer
compound during a "second shot" or overmolding step of fabrication.
[0066] FIGURE 5 shows the same area after overmolding. A skin 304 of the
second polymer
now appears on the bottom surfaces and sides of each of the cores 400, and in
this embodiment
completes the support members 302. While in one embodiment the skins 304 could
be overmolded
separately on each core 400, in the illustrated embodiment the skins 304
within the support member
group 300 are part of a continuous phase. To save cost, the area covered by
skins 304 is limited
and, as seen in FIGURES 3 and 5, does not include a majority of the tile body
lower surface 306.
The skins 304 preferably do not extend to cover the centers of the annular
cores 402 or other
regions outside of crush pads 406. Lateral runners 502 connect a common fill
point 504 to each of
the skins 304. It has been found that as the second of a double-shot
injection, skins 304 molded of a
SEBS TPE compound have excellent adherence to the preferably polypropylene
compound cores
400 (FIGURE 4). As completed, the composite support members 302 are of
approximately the
same depth (in a direction orthogonal to the web 200) as the support ribs 308.
The support
members 302 provide further structural support to the web 200 but at the same
time act as a friction
surface to grip the surface upon which the tiles are laid.
[0067] FIGUREs 6 and 7 are details of a similarly sized area on the top of
tile 102, before and
after overmolding, illustrating one group of pads 106, which are
interconnected in a continuous
phase of solidified second polymer compound. In the illustrated embodiment,
each of the
overmolded pads 106 resides in a shallow recess or receptacle 600 whose
surface is lower than that
of the general upper surface 108. For each recess 600 there is provided at
least one through-hole
602 which communicates the top surface of the tile web 200 to a lower surface
thereof. In the
illustrated embodiment the through-holes are a small fraction (about 5%) of
the bottom of the
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,
recesses 600, as the viscosity (at molding temperature) of the preferred
second polymer compound
is low enough, and the second-shot temperature and injection pressure are high
enough, that no
larger through-holes are necessary to flow molten polymer from the lower side
of the tile body 104
to the upper side thereof, nor is more than one through-hole per recess 600
necessary in the
preferred embodiment. Limiting the size of through-holes 602 enhances the
structural integrity of
the tile 102. However, in alternative embodiments, the size and/or number of
the through-holes 602
may be increased to accommodate more highly viscous second-shot polymer
compounds.
[0068] The recesses 600 are each laterally surrounded by a crush ring 604.
Each crush ring 604 is
finished to be smooth (in contrast, the general upper surface 108 of the body
104 is preferred to be
textured) and is slightly raised relative to the general upper surface 108.
The crush rings 604
provide a tight overmold shutoff that prevents the flashing of the second
polymer compound outside
the confines of the crush rings 604.
[0069] FIGURE 7 is a detail of the tile upper surface after the overmolding
step. The second
polymer compound is injected into the mold at one or more points adjacent the
lower surface of
body 104, flows through each of the through-holes 602, and occupies cavities
in the second-shot
mold to create the raised pads 106. A top surface of the pads 106 is raised
above that of general
surface 108, creating a nonslip surface characteristic. Through this
methodology overmolding
artifacts on the upper surface of the tile 102 are avoided, producing a more
pleasing appearance.
[0070] FIGURE 8 is a sectional view of two tiles 102 joined together, taken
through annular
support members 800, linear support members 802 and rigid ribs 308. Each skin
304 completing a
support member 800, 802 has a portion 810 which is formed on the lower end or
bottom surface of
each core 400, 402. Preferably, each skin 304 also includes portions 812 which
cover all or
portions of adjoining side walls of the cores 400, 402.
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[0071] The rounded square or annular support members 800 are each in
approximate registration
or alignment with the edges or lateral periphery of a respective raised pad
106 on the upper surface
108 of the tile 102. The support members 800 will receive any weight placed
particularly on the
raised pads 106 and will prevent any shear stress from developing in nearby
regions of the
horizontal web 200. The support members 800 and 802 each help support weight
placed on the
upper surface 108 of tile 102, while at the same time providing a friction or
nonslip surface that will
engage the substrate on which the tile is placed. The rigid members 308
provide rigid support of the
entire tile 102 and delimit any compression of the TPE skin 500, the lower
surface of which is
preferably in the same plane as the lowest portion of ribs 308. FIGURE 8 also
shows the preferred
profile of lateral edges 202, 204, which is planar and orthogonal to the plane
of web 200. The
components of the adjacent tiles 102 in FIGURES 8 and 9 have been stippled
differently to
illustrate that they can be of different colors.
[0072] FIGURE 9 is a magnified diagonal cross section (lower side up) of part
of a tile 102, taken
through two raised pads 106, support members 800 underneath and in approximate
registry with
respective ones of the raised pads 106, a central fill point 504 and two
runners 502. In this
illustrated embodiment, one central second-shot polymer compound fill point
504 is provided for
the skins of an entire group 300 of twelve support members 800, 802, and four
associated raised
pads 106 on the upper surface 108 of the tile 102. This illustrated embodiment
has sixteen fill
points 504 on tile 102, one for each interconnected group 300 of support
members 302 and
associated pads 106. In an alternative embodiment the polymer compounds used
for different ones
of the fill points could be in different colors, producing groups of pads 106
on the upper surface 108
which are colored differently than other groups of pads 106.
[0073] The central fill point 504 is connected by a set of runners 502 which
extend laterally from
the fill point 504, and on the lower surface of the web 200, to each of the
support members 800, 802
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in the group 300 where the fill point 504 is located. In the illustrated
embodiment, there are four
main runners 502 that are separated by ninety degrees from each other. At its
end remote from the
fill point 504, each runner 502 branches into three branches 900 that
respectively connect to an
annular support member 800 and two flanking linear support members 802. As can
be seen in the
sectioned runners 502, one of the branches 900 of each runner 502 is
continuous with a through-
hole 602, providing a conduit for the second polymer compound to the upper
side 108 of the tile
102.
[0074] FIGURE 9 also shows a latch 206 which has been inserted into a
respective loop 208. The
loop 208 is preferably molded as an extension of a rigid rib 308 in an
adjacent tile 102. The latch
206 is integrally formed with web 200 and is formed in a gap between two ribs
308 that are adjacent
an edge 202. The gap forming the discontinuity in linearly aligned rib
segments 308 is large
enough to have the latch 206 and the loop 208 disposed therebetween.
100751
FIGURE 10 is a bottom plan view of a one-sixteenth portion 998 of a tile
102, the
illustrated portion 998 occupying an outer comer of tile 102. This comer 998
has three ribs 308 that
surround the group 300 of support members 302. A rib segment 1000 is aligned
with and
positioned slightly laterally inwardly from an edge 204 of the tile 102. Rib
segment 1000
continuously curves on its left side (as seen in this FIGURE) to form a
boundary for a channel 1002.
Rib segment 1000 has a section 1004 which continuously curves from the right
side of rib section
1022 to become parallel and laterally inwardly offset from lateral edge 202,
terminating at a gap
1006. A rib segment 1008 defines an upper right hand boundary of the portion
or cell 998 and
includes a portion 1010 that is in parallel with the lateral edge 202, a
portion 1012 which helps
define a boundary for a trim channel 1014, and a curved portion in between
these. A third rib
segment 1016, defining an interior corner of the cell 998, includes a portion
1018 that helps define
channel 1002, a portion 1020 that helps define channel 1014, and a curved
transition between them.
17
CA 02831266 2013-10-25
[0076] A portion 1022 of the rib segment 1000 that is near and parallel to
lateral edge 204 has a
loop 208 integrally formed with it. The loop 208 is connected to the rest of
tile 102 only by a pair
of widely spaced-apart and limited connection points 1024 and 1026. A cross-
section of loop 208
and its length between connection points 1024 and 1026 are so preselected that
loop 208 will be
relatively flexible in comparison to the latch 206. The latch 206 may be a
solid plug (not shown) or,
as appears in the illustrated embodiment, may include a downwardly depending,
inwardly facing
convex wall 1028, connected at both of its ends to a downwardly depending,
laterally outwardly
facing wall 1030. The entire wall 1028, and a substantial portion of the wall
1030, are attached to
the general lower surface 306 of the tile 102. Neither arcuate wall 1028 nor
wall 1030 is as long as
loop 208. These differences in size and degree of attachment to the rest of
the tile 102 make the
latch 206 substantially rigid relative to loop 208. In any interference
between them, therefore, the
loop 208 will flex or expand and the latch 206 will not substantially deform.
100771 FIGURE 11 is a highly magnified sectional view showing how a male latch
206 is
snapped into a receiving female loop 208 of an adjacent tile 102. The outer
wall 1030 of the latch
206 has a surface 1100 which is beveled or sloped so that it will cam against
an upper corner 1102
of the lateral edge 204. The inner wall 1028 of the latch 206 has a sloped or
beveled surface 1104
which will cam against an upper interior corner or ridge 1106 of the loop 208.
As the latch 206 is
pressed downward into the loop 208, an interference will develop between the
inner facing wall
1028 of the latch 206 and the loop 208, as shown by the hatched region 1108.
Since wall 1028 of
latch 206 is substantially more rigid than loop 208, the loop 208 will
elastically expand along its
length and will flex laterally outwardly from the tile 102 to which it is
attached (in FIGURE 11,
rightward). Once the latch 206 is driven down far enough, a horizontal ledge
1110 of the outer
latch wall 1030 will snap past a lower comer 1112 of the lateral edge 204 and
will slide to the left
along the general lower surface 306 of the adjacent tile 102. Even after this
happens the loop 208
18
CA 02831266 2013-10-25
will remain under tension. This biases lateral edge 204 against mating lateral
edge 202, producing a
tight fit of these two surfaces and the tiles of which they are a part. As
shown, the depth (in a
direction orthogonal to the plane of web 200) of walls 1028, 1030 is slightly
less than the depth of
the walls of rib segment 1022 and loop 208, permitting a degree of overdrive
when snapping the
latch 206 into the loop 208. FIGURE 12 is an isometric sectional view of two
adjacent tiles taken
through a loop 208 and an inserted latch 206, again illustrating the
interference fit between the two.
100781 FIGURE 13 is a schematic detail, from a bottom view, showing a latch
206 as it is
received into a loop 208. The loop 208 is illustrated here in its unstretched
and unflexed condition.
As so superimposed a region 1108 of interference will exist between loop 208
and an inner wall
1028 of the latch 206, and this region 1108 will be of variable depth as
measured in a lateral
inward/outward direction. The inner wall 1028 has an inwardly-facing surface
1300 which has on it
a point 1302 which is innermost and is farthest away from the lateral edge 202
of body 104 (see
FIGUREs 11 and 12) with which it is most closely associated. Preferably the
inwardly-facing
surface 1300 is arcuate and convexly so relative to the center of the tile
102. Surface 1300 can be
more sharply curved than is shown. As one travels away from the innermost
point 1302 along the
surface 1300 (to the left or right in this FIGURE), the depth of interference
region 1108 decreases,
until the interference region 1108 vanishes altogether as one approaches
either end 1304, 1306 of
the surface 1300. Preferably the inner surface 1308 of the loop 208 is
arcuately concave. More
preferably the degree of concavity of the inner surface 1308 is less than the
degree of convexity of
the inward facing surface 1300 of the latch 206, that is, the surface 1308 is
more gradually curved
than surface 1300. In this way, the interference is minimized at the
attachment points 1024, 1026,
preventing the loop 208 from becoming over-stressed at its attachment points
1024, 1026 and
reducing the likelihood of loop failure. It is relatively easy for loop 208 to
stretch and flex at its
middle, opposite innermost latch wall point 1302, as the length to either
point 1026 or point 1024 is
19
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long. But the resistance to such stretching and flexing will increase as one
approaches point 1024
or point 1026, as the points of attachment are closer. Varying the degree of
interference in the
manner shown therefore reduces the stress at the attachment points 1024, 1026.
The attachment
points 1024, 1026 may be reinforced with gussets 2502 (see FIGURE 25) to
prevent loop breakage.
100791 FIGURE 14 is a schematic block diagram illustrating steps in a floor
tile manufacturing
process according to the invention. Step 1400 is a mold design step including
many substeps, of
which three are pertinent here. The mold (and the part produced thereby)
should have certain
characteristics, and these include the provision of flow-through holes at
substep 1402. The flow-
through holes are positioned to communicate the recesses 600 for the pads 106
(see FIGURE 6), on
the upper surface 108, to the central second polymer compound fill points 504
adjacent the lower
surface 306. The second shot of polymer compound will use these flow-through
holes (602 in
FIGURE 9) to access the cavities 600 in which the pads 106 are to be created.
The size and number
of through-holes 602 will be dictated in part by the viscosity of the second
polymer compound at
molding temperature, and the injection molding pressure to be used.
[0080] The designer also, at substep 1404, provides for crush rings 604
(FIGURE 6) on the top
surface 108 of the tile 102, and crush pads 406 (FIGURE 8) on the bottom
surface 306 of the tile
102. These surfaces preferably are flat, smooth, and slightly raised or
outward in relation to the rest
of the surfaces of which they are a part. The crush rings 604 and crush pads
406 closely laterally
surround the regions into which the second polymer compound is to flow,
creating a clean shutoff
of the second polymer compound and preventing flashing. This is particularly
important on the
upper surface 108 as it will affect the aesthetic acceptability of the tile
102.
100811 At substep 1406, the designer provides runners 502 (see FIGURE 9) to
communicate the
central fill points 504 with the support members 800, 802 and the through-
holes 602. The result of
CA 02831266 2013-10-25
step 1400 will be tooling that can be used in a two-shot injection molding
process according to the
invention.
[0082] The mold is placed in an injection molding press and a first shot of
polymer compound is
injected into the mold at step 1408. As explained above, this first polymer
compound is
thermoplastic and preferably is relatively rigid, and can comprise
polypropylene. Then, at step
1410, the mold is prepared for a second injection shot, in which further
molding structure is used to
define surfaces of pads 106, skins 304 and runners 502. A second shot of
polymer compound is
then injected into the mold, using a second polymer compound which has
different characteristics
than the first polymer compound, such as being harder or softer or being of a
different color.
Preferably the second polymer is elastomeric and for example can be
constituted by SEBS TPE or
another TPE. A preferred result of molding steps 1408 and 1410 is a composite
floor tile which
includes a body capable of withstanding a large amount of weight (such as
might be imposed by a
vehicle wheel) but still has nonslip characteristics on both its upper and
lower surfaces.
[0083] FIGUREs 15 ¨ 18 illustrate an embodiment of the invention in which the
overmolded
structure includes a peripheral seal that is used to seal to adjoining tiles
when a floor surface is
assembled. FIGURE 15 is an isometric view of a floor tile body 1500 that is
similar to body 104
(FIGURE 2) but with lateral edges 1502, 1504 that are stepped rather than
orthogonal to the web
200 and planar. This view is taken after molding the first polymer compound
but prior to
overmolding. In this illustrated embodiment, stepped lateral edge 1502 has a
laterally inwardly
disposed vertical surface 1506 which extends downwardly from general upper
surface 108 to a
horizontal shelf 1508. The horizontal shelf extends laterally outwardly from
vertical surface 1506
to a second, laterally outwardly disposed vertical surface 1510. Vertical
surface 1510 extends from
the shelf 1508 to the lower surface 306 of the tile body 1500.
21
CA 02831266 2013-10-25
,
[0084] In the illustrated embodiment a lateral edge 1504 is similar in form to
lateral edge 1502. A
first, laterally inwardly disposed vertical surface 1512 extends from general
upper surface 108 of
the tile body 1500 to a shelf 1514. The shelf 1514 extends laterally outwardly
from the vertical
surface 1512 to a second, laterally outwardly disposed vertical surface 1516.
The vertical surface
1516 extends from the shelf 1514 to the general lower surface 306 of the tile
body 1500. Surfaces
1506, 1508 and 1510 define a recess (more particularly, a step) 1518 which can
be subsequently
occupied by an overmolded peripheral seal. Similarly, surfaces 1512, 1514 and
1516 define a step
1520 which can be subsequently occupied by an overmolded peripheral seal,
preferably continuous
with the seal occupying step 1518. While this illustrated embodiment uses
steps 1518, 1520 as
locations which can be occupied by a peripheral seal, other profiles are
possible, such as curved or
keyed profiles and/or ones which include a physical interference to the
delamination of the
peripheral seal from the body 1500. As before, it is preferred to mold the
body 1500 from a
relatively strong and rigid polymer compound such as one comprising
polypropylene.
[0085] FIGURE 16 shows the view shown in FIGURE 15, but after at least one
overmolding step
in which a peripheral seal 1600 has been overmolded into the steps 1518, 1520
to laterally surround
the body 1500. The creation of the seal 1600 can take place during, before, or
after the creation of
the raised pads 106 and skins 304 (FIGURE 9), and the seal 1600 can be
constituted by a polymer
compound which is the same as or which is different from the polymer compound
constituting pads
106 and skins 304, in terms of composition, hardness, and/or color. It is
preferred that the seal 1600
be constituted by a compound comprising SEBS TPE or other elastomeric
compound.
100861 A top surface 1602 of the seal 1600 is preferred to be coplanar with
the general surface
108 of the body 1500. On one side of the tile body 1500, the horizontal
surface 1602 extends from
vertical surface 1506 laterally outwardly to a vertical surface 1604 of the
seal. The vertical surface
1604 of the seal extends from seal horizontal surface 1602 until it meets with
vertical surface 1510
22
CA 02831266 2013-10-25
of the body 1500, with which it is coplanar. As better seen in FIGURE 17, the
otherwise planar
vertical surface 1604 is interrupted by a bump 1606 which is convex in
section.
100871 On an adjacent side of the body 1500, a horizontal surface 1608, which
is continuous with
the surface 1602 and preferably coplanar with upper surface 108 of body 1500,
extends laterally
outwardly from the lateral edge of vertical surface 1512 to a vertical surface
1610 of the seal 1600.
The vertical surface 1610, which in general is orthogonal to surface 108 and
planar, is interrupted
by a convex bump 1612. Otherwise, surface 1610 meets and is coplanar with
vertical surface 1516
of the body 1500. Surfaces 1604, 1610 form a ninety degree corner at their
junction.
[0088] As shown in FIGURE 18, when adjacent tiles 1800 are assembled such that
a latch 206 is
inserted into a loop 208, the bumps 1606, 1612 are in interference with each
other, as shown by
hatched interference region 1614. This creates a substantially watertight
peripheral seal of each tile
to the other tiles in the floor surface.
100891 A further embodiment of the invention is shown in FIGURE 19, in which
certain structure
adjacent the lower surface 306 of a tile 1900 is shown in phantom. This
embodiment is similar to
that shown in FIGURE 2, with the difference that the second shot of polymer
compound is
introduced at upper surface 108 of the body 104, rather than at lower surface
306 thereof. For each
of a group 300 of pads 106 and skins 304, a gate 1902 is formed to extend from
the upper surface
108 of body 104 to the lower surface 306 thereof. The gate 1902 is continuous
with runners 502 on
the lower surface, which in turn communicate with the skins 304, the through-
holes 602 and the
cavities 600 in which are molded the pads 106. In making the second-shot
injection, the second
polymer compound flows through the gates 1902 to the lower surface 306, thence
through runners
502 to the skins 304 and the through-holes 602, and finally back through the
body 104 to the
cavities 600 to mold the pads 106. In an alternative embodiment, the pads 106
are omitted and only
23
CA 02831266 2013-10-25
structure adjacent lower surface 306 is molded, except for dots on the upper
surface that result from
the gates 1902.
100901 It is possible to overmold certain features on the bottom surface of
the tile without creating
raised pads from the second polymer compound on the top surface thereof. A top
surface of such an
embodiment can be seen in FIGURE 20, in which the entire top surface 2000 of a
tile 2002 is
molded of the first polymer compound. While the top surface 2000 can be
featureless except for
texturing, in this illustrated embodiment an array of features 2004, which can
be rounded squares or
which can take any other desired shape, are upstanding from a general top
surface 2006. A bottom
surface of this illustrated embodiment can be exactly as it appears in FIGURES
3, 5, 10, 12 and 13.
In this embodiment there are no through-holes or gates between the upper and
lower surfaces of the
tile 2002. This embodiment and the embodiment shown in FIGURES 1 ¨ 13 can be
made using
much the same molding apparatus, by swapping out a cavity-side mold insert
adjacent the top
surface 108, 2000 and leaving a core side (adjacent the lower surface) alone.
This illustrated
embodiment will still exhibit non-slip properties relative to the substrate on
which it is placed, may
have better chemical and wear resistance, and may cost less to produce.
[0091] Considering together the embodiment illustrated by the combination of
FIGUREs 3, 5, 10,
12, 13 and 20, raised features 2004 are more likely to receive a
disproportionate amount of weight
from a vehicle or other heavy object superimposed on the tile 2002. It is
therefore preferred that
some of the support members, such as members 800 (FIGURE 8), receive all or
some of the
columnar load placed on any raised feature 2004. In the illustrated
embodiment, each annular
support member 800 (see FIGURE 8) is in approximate registration with a
respective raised feature
2004 and as such will militate against shearing between the boundary of the
raised feature 2004 and
the surrounding general surface 2006.
24
CA 02831266 2013-10-25
[0092] FIGUREs 21 and 22 show a fifth embodiment of the invention in which
modifications to
the latch and loop structure have been made. In this embodiment an undercut or
trench 2100 is
made behind (laterally inwardly from) the lateral edge 204, but laterally
outwardly from the rib
segment 1022, to approximately fifty percent of the thickness of web 200. The
undercut 2100
extends in parallel to edge 204 for the interior length of the wall segment
1022 between its
attachment points (1024, 1026; FIGURE 10) with female loop 208. The undercut
2100 leaves a
downwardly depending flange 2102 which, when surface 2104 of outer wall 2106
slides vertically
downward along surface 204, will flex inward (to the left in this picture) in
approximately the
direction of arrow 2108. The depth of the undercut 2100 is chosen to get a
sufficient flexure of the
flange 2102 upon snapping the tiles together, and may be more or less deep
than shown depending
on the flexural modulus of the polymer used to mold tile body 104. Flexing
flange 2102 permits
latch 206 to more easily snap into loop 208 and places less stress on loop 208
while joining two
adjacent tiles. The inner latch wall 2110 may be made thicker and
preferentially has a preferably
flattened, inner ramped surface 2112 which cams against corner 1106 as the
right tile 102C is
pressed downward to join it with left tile 102D, until ledge 2120 clears lower
edge 2116 of flange
2102. Ramped surface 2112 preferably extends downwardly and laterally
outwardly from
innermost limit 1302 of latch 2118. After the tiles 102C, D are snapped
together, there will remain
a hatched interference region 2114 between inner latch wall 2110 and outer
female loop 208,
keeping the tiles 102C, 102D biased together or in compression with each
other; the physical
position of loop 208 will actually be displaced rightward from that shown in
FIGURE 21.
[0093] Preferably a lower edge 2116 of the flange 2102 is slightly relieved
(or upwardly
displaced) from the plane of the general lower surface 306. This permits an
easier overdrive of
male latch 2118 into female loop 208 and better assures an audible click when
horizontal ledge
2120 snaps beyond lower edge 2116.
CA 02831266 2013-10-25
[0094] FIGUREs 23 through 27 show another embodiment of the invention. In this
embodiment,
the bottom view of a tile 2301, shown in FIGURE 23, shows sixteen groups 2300
of support
members 2302. The body 2303 may be molded from a first polymer compound and
have an upper
surface 2602 (see FIGURE 26) and a general lower surface 2306. One or more
upper features 106
(FIGURE 2), such as pads, may be formed or overmolded into the upper surface
2602 with a second
polymer compound. As completed, the upper features or pads 106 on upper
surface 2602 (FIGURE
26) may look identical to the ones of embodiments previously described herein.
One or more lower
features 2302 (FIGURE 23), such as support members or skins, may be overmolded
onto the lower
surface 2306 of the body 2303 from the second polymer compound. As above, the
second polymer
compound preferably has a higher coefficient of friction than the first
polymer compound so that the
upper features 106 and the lower features 2302, or skins, act as nonslip
surfaces. Alternatively or
additionally, they may be made in a color different from that of the tile body
2303.
[0095] FIGUREs 24 and 25 show the details of the tile lower surface 2306.
Specifically, these
FIGUREs show a single group 2300 of support members 2302 before (FIGURE 24)
and after
(FIGURE 25) the second polymer compound is overmolded onto the body 2303 of
the tile 2301.
FIGURE 24 shows there can be seen a plurality of support member cores 400
which depend
downwardly (in this view, extending toward the top of the paper) from the
general lower surface
2306 of the substantially horizontal web 200 that makes up most of the tile
body 2303. One or
more through-holes 602 connect the upper surface 2602 (see FIGURE 26) with the
lower surface
2306. Similarly, one or more vent holes 2402 connect the upper surface 2602
with the lower surface
2306 of the tile 2301. Preferably, each vent hole 2402 is in a location that
is laterally interior to and
within a periphery of a respective upper feature 106. Each upper feature 106
has a through-hole
602 and a vent hole 2402 communicating to it and these are laterally spaced
from each other.
Preferably the vent hole 2402 for any particular pad 106 should be positioned
at a location that is
26
CA 02831266 2013-10-25
farthest from the through-hole 602 therefor, while still being laterally
within the periphery of the
cavity that will form the pad or upper feature 106.
[0096] FIGURE 26 shows the details of an area on the top of tile 2301, prior
to overmolding.
Each overmolded pad 106 (see FIGURE 7) may reside in a shallow recess or
receptacle 2600 whose
surface is lower than that of the general upper surface 2602. For each recess
2600, there is provided
at least one through-hole 602 and at least one vent hole 2402, each of which
communicates the top
surface of the tile web 200 to a lower surface thereof. In the illustrated
embodiment, the through-
holes 602 and vent holes 2402 make up a small fraction (about 5% each) of the
bottom of the
recesses 2600. Each of the recesses 2600 form respective lower portions of the
cavities in which
upper features or pads 106 will be formed, the remainder of the surfaces
thereof being constituted
by the other mold half. Limiting the size of through-holes 602 and vent holes
2402 enhances the
structural integrity of the tile 2301. However, in alternative embodiments,
the size and/or number
of the through-holes 602, and even vent holes 2402, may be increased to
accommodate more highly
viscous second-shot polymer compounds.
[00971 The recesses 2600 are each laterally surrounded by a crush ring 604.
See FIGURE 26.
Each crush ring 604 is finished to be smooth (in contrast, the general upper
surface 2602 of the
body 2303 can be textured) and can be slightly raised relative to the general
upper surface 2602.
The crush rings 604 each adjoin the periphery of a respective upper feature
106 and provide a tight
overmold shutoff that prevents the flashing of the second polymer compound
outside the confines
of the crush rings 604. FIGURE 25 further shows that a portion 2310 of at
least one upper feature,
or pad, 106 (see FIGURE 7) may extend through the vent hole 2402 below the
general lower
surface 2306. As shown in FIGUREs 23 and 25, the portion 2310 extending
through the vent hole
2402 may be discontinuous with or spaced from the second polymer compound of
the lower support
27
CA 02831266 2013-10-25
,
,
member 2302. As described in more detail below, this spacing may be
accomplished by providing
a portion of the crush pad 2406 between the vent hole 2402 and the cores 400.
100981 The crush pad 2406 is formed into the body 2303 in a manner similar to
the crush ring 604
to be slightly lower than the general surface 2306 (in this bottom view, is
slightly raised relative to
general surface 2306). The crush pad 2406 is formed to be closely adjacent all
of the support
member cores 400 and to laterally surround all of the cores 400, the runners
502 connecting the
lower features 304, the through-holes 602, and the vent holes 2402 (and
therefore portions 2310).
The crush pad 406 is finished to have a smooth surface and is used as a
shutoff surface that prevents
the flashing of the second polymer compound during a "second shot" or
overmolding step of
fabrication.
[0100] In an arrangement similar to that illustrated and described previously
(see FIGURE 19), a
second polymer compound gate 1902 is disposed to be adjacent to the lower
surface 2306 and
remote from the upper surface 2602. The gate 1902 communicates with the upper
feature 106
through fill point 504 and a through-hole 602 that extends from the lower
surface 2306 to the upper
surface 2602. The gate 1902 is in direct communication with each lower feature
2302 by a path
which does not pass through the body 2303.
[0101] FIGURE 25 shows the same area after overmolding. The second polymer
compound now
appears on the bottom surfaces and sides of each of the cores 400 as a lower
feature 2302 or skin.
While the second polymer skin could be overmolded separately on each core 400,
in the illustrated
embodiment, the second polymer within the support member group 2300 is part of
a continuous
phase. The second polymer preferably does not extend to regions outside of,
and is contained by,
the crush pads 2406.
28
CA 02831266 2013-10-25
[0102] FIGURE 27 shows that a plurality of upper features 106 and lower
features 800, 802 can
be formed from one gate 1902 (FIGURE 19). It can be seen that the molten
second polymer flows
from the gate 1902 (see FIGURE 19) to the fill point 504 and directly to the
lower surface 2306 to
form the lower features 800, 802. This path does not go through the first-shot
tile body 2303.
FIGURE 27 also shows that each upper feature 106 is in communication with a
respective vent hole
2402. The second polymer flows from the gate 1902, to the fill point 504, and
through the through-
hole 602 to form a respective upper feature 106. For each feature or pad 106,
the second polymer
flows from the through-hole 602 and flows into and fills a respective mold
cavity formed in part by
a recess 2600, and back through the vent hole 2402. In this way, any gas in
the polymer flow-path
is displaced, and defects or voids at the end-of-fill point in the overmolded
upper feature 106 caused
by trapped gas can be minimized or prevented. This trapped gas otherwise can
cause burn marks,
short shots, and/or poor adhesion of the upper features 106 to the body 2303.
[0103] The structure shown in FIGURE 24 is one possible first-shot body
structure that promotes
the displacement of any gas out of the upper feature cavity. Each core 400 may
be interrupted or
truncated to provide lateral separation from the vent hole 2402, which is
preferably placed at a
position farthest away from the through-hole. Where, as here, the upper
feature 106 takes on a
roughly square or rectangular shape, the through-hole 602 and the vent hole
2402 can be disposed in
opposite corners of the upper feature. The positioning of vent hole 2402
preferably should be such
that the molten second-shot polymer flowing from the through-hole 602 will
reach the vent hole
2402 only after reaching the rest of the cavity defined in part by recess
2600. After molding
(FIGURE 25), the separation between core skin 2302 and portion 2310 is
maintained by the crush
pad 2406, which seals the portion 2310 of the upper feature 106 or pad
extending through the vent
hole 2402 from the lower features 2302 or skins molded onto the cores 400.
This separation of the
top flow (through the through-hole 602, over the recessed area 2600, and
through the vent hole
29
CA 02831266 2013-10-25
,
2402) and the bottom flow (from the fill point 504, to the runner 502, to the
lower feature 2302 or
skin) prevents the top and bottom flows from interfering with one another in
correctly filling the
volumes into which the second polymer is to be overmolded.
101041 FIGURE 28 illustrates a method 2800 of manufacturing a modular floor
tile 2301
according to the invention. At 2802, the first-shot injection mold is formed,
including forming
(2804) structures which will make one or more through-holes 602, and forming
(2806) one or more
vent holes 2402. Optionally structures which will form one or more recesses
2600 can be formed at
step 2808, the recesses 2600 then acting as portions of the cavities in which
the upper features or
pads 106 will be later molded. At step 2810, structure defining the crush
ring(s) 604 are formed on
the upper surface 2602 of the first-shot body 2303, so as to laterally
surround each upper feature
and preferably to be elevated above the general upper surface. For each such
upper feature, at least
one through-hole and at least one vent hole is made, and these preferably are
spaced to be at
opposite ends of the upper features to which they communicate. At step 2812,
crush pad(s) 2406
are defined on the lower surface 2306 of first-shot body 2303, so as to
laterally surround each lower
feature to be molded in the second shot, and also to laterally surround each
vent hole 2402.
[0105] At step 2814, the second-shot mold half is created. The structures
formed in this step
include a fill point or gate 504, 1902, which is located to be adjacent the
lower surface 2306 of the
first-shot body 2303 and remote from the upper surface 2602 thereof. Cavities
for the second-shot
runners 502 (FIGURE 27) are also formed at this step.
[0106] The first polymer compound is injected into the first-shot injection
mold at step 2820; this
will form a first-shot tile body 2303 as seen in FIGUREs 24 and 26.
[0107] The second polymer compound is injected into a second-shot injection
mold at step 2822,
to overmold upper features 106, and preferably also lower features 800, 802,
onto the respective
CA 02831266 2013-10-25
upper and lower surfaces of the tile body. The second polymer compound is
introduced (2824) to
the mold at a gate 1902 and fill point 504, for each connected group of upper
and lower features. In
one embodiment, there are 16 such gates and fill points on one tile. The
second polymer flows by
runners 502 to the through-hole(s) at step 2824. At step 2826, the second
polymer flows in each
connected through-hole 602 from the lower surface to the upper surface,
reaching the cavity(ies)
which each define respective upper feature(s). The upper feature cavity(ies)
are filled at step 2828.
At step 2830, the crush ring(s) shut off the second polymer compound from
flashing across the
upper surface of the part. The second polymer compound pushes any gas through
vent hole(s)
2402, minimizing or obviating any defects in the upper feature(s). To
positively assure that this is
accomplished, at step 2832 second polymer compound may flow through each vent
hole 2402 to
protrude onto the lower surface 2306. The crush pad 2406 and associated mold
half isolate this
second polymer portion 2310 from next-adjacent lower features 800.
[0108] While the second polymer compound is molding the upper feature(s) at
steps 2824 ¨
2832, it can also create lower feature(s) at steps 2834 ¨ 2840. At step 2834,
second polymer
compound flows from gate 1902 and fill point 504 into and through one or more
runners 502. At
step 2836, the runners 502 permit second polymer compound to reach each of the
lower feature(s)
800, 802, where the cavity(ies) defining them are filled (2838). At step 2840,
the crush pad(s)
2406, in conjunction with the mating second-shot mold half (not shown), shut
off the molten second
polymer compound, preventing the flash of same over the lower surface 2306.
The mold half and
crush pad(s) 2406 also isolate second polymer portion 2310 from the second
polymer compound
flowing in to form feature(s) 800, 802. In this way, there is no hydraulic
interference between the
molten polymer compound flowing into and forming the upper feature(s) and the
molten polymer
compound flowing into and forming the lower feature(s), and any air or inert
gas will be expelled
from the upper surface features.
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[0109] The embodiment shown in FIGUREs 29 ¨ 30C is in general similar to the
embodiment
shown in FIGUREs 23 ¨ 27, with the following changes. A set of elongate
drainage vents 2902 is
formed such that each drainage vent 2902 extends from the general top surface
2904 of the body
2906 to the general lower surface 2908 thereof (FIG. 30B). In this illustrated
embodiment the
drainage vents 2902 occupy only a small fraction of the surface area of lower
surface 2908, as the
illustrated tile 2910 is meant to take on the weight of a vehicle as
transmitted by a vehicle tire (or
even a jack stand), and as such too many voids in the tile body 2906 would
compromise its
integrity. In the particular embodiment illustrated here, the drainage vent
surface area as measured
at the general lower surface 2908 is about 3% of the total. Preferably the
collective surface area of
the vents, as measured at the general lower surface 2908, should be no more
than about 11% of the
surface area of the general lower surface 2908.
[0110] In this embodiment, pads or features 106 are formed to upwardly extend
from the general
upper surface 2904 by a small amount. As before, the pads or features 106 are
formed by a second-
shot injection molding operation of a material which can be softer and/or more
elastomeric than the
first-shot material forming the body 2906. The features 106 can be formed on
smooth, flat, slightly
proud crush rings 604 so as to provide a complete shutoff and avoid flash on
the general upper
surface 2904 of the part. Each group of pads 106 can be considered to be a
single feature which is
injection-molded in a continuous phase from a common fill point (seen, for
example, at 3001 in
Figure 30B).
[0111] The drainage vents 2902 can be laterally spaced from the upper second-
shot features 106
and the crush rings 604 on which they are formed. Where, as here, the tile
2910 is composed of
sixteen (four by four) portions 2912, some of which can be trimmed off by a
consumer, the drainage
vents 2902 conveniently can be located at the borders of these portions 2912
and their directions of
elongation can conform to the border between the portions 2912.
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[0112] Details of this embodiment are best seen in FIGUREs 30A-C. Each
elongate drainage
vent 2902 is radiussed (2914) at its junction with the general upper surface
2904. The radiussing
2914 does not continue all of the way through the depth of the tile body 2906
(which, for example,
can be 1/8 in.), but extends less than half way. Thereafter, the vent 2902 is
defined by sloped
sidewalls 2916 which extend to their junction with the general lower surface
2908. The degree of
bevel or slope of sidewalls 2916 relative to the vertical can be 30 degrees.
This permits each
drainage vent 2902 to collect more moisture from the top surface 2904 and
funnel it to the volume
below the body 2906. In the illustrated embodiment, the radiussing 2914 and
beveling expands the
vent's surface area by more than 300% relative to its surface area at the
plane of the bottom surface
2908.
[0113] As seen in FIGURE 30B, the drainage vents 2902 can be laterally spaced
from the support
member groups 2300 and the crush pads 2406 on which they are formed. As
before, an interrupted
circumferential rib 3000 laterally surrounds each support member group 2300.
This rib 3000 is
molded with and depends from first-shot body 2906 and can be in the shape of a
rounded square, as
shown; it delimits a one-sixteenth portion 2912 of the tile 2910. The rib 3000
is made of several
components. A u-shaped rib portion 3002 starts at a point on an interior side
of portion 2912, bends
to be parallel to exterior tile side 3004, and then bends up again to be
parallel to an exterior tile side
3006. Rib section 3002 includes two curved transitions between longitudinal
and transverse
segments. A loop 3007, in general similar to the loops previous described, is
molded to be
continuous with the rib portion 3002 and is attached thereto by loop
connection points 3008 and
3010. In the illustrated embodiment, these have been strengthened by fillets
3012 and 3014,
respectively, which extend between the vertical external surfaces of rib
portion 3002 and loop 3007
at their points of attachment.
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[0114] Rib portion 3002 terminates prior to latch 2118, which takes the form
previously
described. A rib portion 3016 forms (in this FIGURE) the upper right-hand
corner of the rib 3000
and includes a curved transition at its corner. Rib portion 3016 is
discontinuous with upper left rib
portion 3018, which is in mirror image to the rib portion 3016. The
discontinuity of the rib 3000
permits fluid which the vents 2902 collect and drain to flow from the volume
delimited by rib 3000
to points exterior to that volume.
[0115] The rib portions 3002, 3016, 3018 are laterally spaced from similar rib
portions which are
disposed in neighboring tile portions 2912. The lateral spacing, which for
example can be 0.17 in.,
defines a channel 3020 between neighboring tile portions 2912. In this
embodiment the elongate
drainage vents 2902 are disposed within these channels 3020. The collocation
of the vents 2902
within the channels 3020 makes it easier for a consumer to trim off selected
one-sixteenth squares
2912 from the tile 2910; the consumer can use the channels 3020 as a cutting
guide.
[0116] While the illustrated tile 2910 has sixteen portions 2912, other,
smaller tiles can be molded
that consist of fewer portions 2912. For example, a tile (not shown) can be
molded which includes
only one portion 2912. There can be 1 x 2, 2x2, 2x3, 3x3, 4x1, etc. sizes
which then would include
two, four, six, nine, or four portions, respectively; the repeating pattern of
tile 2910 makes it
convenient to assemble to these smaller tiles to fit to an actual floor area.
In one embodiment each
portion 2912 is 3 in. by 3 in., while the largest tile 2910 is one foot
square, or 12 in. by 12 in.
[0117] In general, the locations of the drainage vents 2902 are chosen so as
to be laterally
displaced from both the features 106 (which may include overmolded components
both on top of
and on the bottom of the tile body 2906) and from the crush rings 604 and the
crush pads 2406
which laterally surround these overmolded features.
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[0118] FIGUREs 31 ¨ 32C illustrate an embodiment which is similar to the one
shown in
FIGUREs 29 ¨ 30C, but without the second thermoplastic material being
overmolded on the body.
In this "single shot" embodiment, a floor tile 3100 has a general upper
surface 3102 and a general
lower surface 3104 (see FIGURE 32B). A set of raised pads 2004 extend upwardly
from the
general upper surface 3102, but these are formed at the same time as the body
3106, of the same
material. As before, a set of elongate drainage vents 2902 extend from the
general upper surface
3102 to the general lower surface 3104.
[0119] As best seen in FIGURE 32B, an interrupted or discontinuous
circumferential rib 3000
delimits a one-sixteenth portion 3200 of the tile 3100. The rib 3000 has a u-
shaped portion 3002
from which extends a loop 3007. Comer rib portions 3016 and 3018 complete the
rib 3000, which
can take the faun of a rounded square. Adjacent ones of the ribs 3000 define
channels 3020
therebetween, and the drainage vents 2902 are disposed in these channels 3020.
The part is
completed with the addition of four internal corner ribs 3202 that are
disposed arnong the group of
pads 2004. As best seen in FIGURE 32C, the drainage vents 2902 continue to be
radiussed at 2914
and beveled at 2916, such that their surface area as measured at the plane of
the general upper
surface 3102 is more than 300% of their surface area as measured at the plane
of the general lower
surface 3104.
[0120] The drainage vents 2902 may be incorporated into any of the embodiments
shown in
FIGUREs 1 ¨ 14 or 19 ¨ 28.
[0121] In the embodiment shown in FIGUREs 33 ¨ 34C, a tile 3300 has a general
upper surface
3302 without any upstanding pads. This embodiment is injection-molded from a
single
thermoplastic material and its composition can be similar to that used to make
the first-shot tile
bodies as above described. Four arrays or groups 3304 of elongate drainage
vents 3306 ¨ 3310 are
CA 02831266 2013-10-25
formed to extend from the upper surface 3302 to the general lower surface 3312
of the tile (see
FIGURE 34B). The drainage vents 3306 ¨ 3310 are of uniform width (such as 1/8
in. as measured
at lower surface 3312) but of varying length. The cumulative surface area of
the drainage vents
3306 ¨ 3310, as measured at the lower surface 3312, is only a small fraction
of the surface area of
the tile 3300 (such as about eleven percent), as the tile 3300 is meant to
receive the weight of a
portion of a motor vehicle and as such care must be taken not to compromise
the strength of the tile
3300.
[0122] The lateral positions of fill points 3314, at which molten polymer is
introduced into the
mold, are denoted by crosses. The fill points 3314 preferably are on the lower
tile surface 3312 and
correspond to the injection mold gates. In this embodiment, the drainage vents
3306 ¨ 3310 within
any array 3304 are arranged in a somewhat radiant fashion around their
respective fill points 3314.
That is, the axes of elongation of each of the drainage vents 3306 ¨ 3310 are
more in alignment with
a radius from a respective fill point 3314, than they are transverse to it.
The longest vents 3306
have axes which exactly coincide with radii from an associated fill point
3314, but in the illustrated
embodiment, and for reasons of aesthetics and uniformity of distribution, the
axes of vents 3308 and
3310 are less so aligned, and instead have been selected to be parallel to the
axis of the long
drainage vent 3306 with which they are most closely associated.
[0123] In the mold, the drainage vents 3306 ¨ 3310 correspond to solid
structures around which
the molten polymer must flow in order to fill the mold. Molten polymer will
flow radially away
from each of the fill points 3314. As disposed in FIGURE 33, the impedance of
the drainage vents
3306 ¨ 3310 to the flow of molten polymer is reduced if not minimized, and
this aids in the
successful filling of the mold. In other embodiments (not shown) the vents
3306 ¨ 3310 can be so
arranged that their axes of elongation are completely in alignment with
respective radii with an
associated fill point 3314, creating a star pattern.
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[0124] As in previous embodiments, tile 3300 has fillet-augmented loops 3007
which engage
latches 2118 of adjacent tiles, in a manner previously described.
[0125] Referring particularly to FIGURE 34B, a set of straight, elongate,
supporting ribs 3400 ¨
3402 are molded with tile body 3404 to depend from the general lower surface
3312. In this
embodiment the ribs 3400 ¨ 3402 are disposed to be in parallel with the
straight, elongate drainage
vents 3306 ¨ 3310. Ribs 3400 flank the long vent 3306 and are respectively
positioned to be
midway between the long vent 3306 and the medium-length vents 3308. Here, they
are chosen to
be of a length similar to that of the medium-length vents 3308. Ribs 3402 are
shorter than ribs
3400, and are positioned midway between medium-length ribs 3308 and short ribs
3310. As so
distributed, the ribs 3400, 3402 equally support a load placed on top surface
3302 across any of the
vents 3306 ¨ 3310, so that there will be no shear force which develops in the
body 3404 across any
of the vents 3306 ¨ 3310.
[0126] The rib support structure for the web 3406 of the body 3404 further
includes a u-shaped
rib 3002, which (in FIGURE 34B) starts on an interior side of a 1116th portion
3407 of the tile 3300,
proceeds along a side 3408, and curves along side 3410 until it ends near
latch 2118. The u-shaped
portion 3002 includes two rounded corners of a square. A third rounded corner
of this square is
defined by rib portion 3016, in (in this FIGURE) the upper right-hand corner.
The upper left hand
corner is defined by straight rib portions 3412. Straight rib portions 3412
are not conjoined so as to
avoid the fill point 3314. Rib portions 3002, 3016 and 3412, in combination
with similar rib
portions of adjacent tile portions 3407, define channels 3020 which may be
used by a consumer to
trim one or more portions 3407 off of the rest of the tile body 3404. Loops
3007 are formed with
rib portions 3002 and are used to attach the modular tile 3300 to the latches
2118 of other, similar
tiles.
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[0127] As seen in FIGURE 34C, and per previously described embodiments, each
drainage vent
3306 -- 3310 is radiussed (2914) at its junction with general upper surface
3302. Sidewalls 2916 of
the drainage vents 3306 ¨ 3310 are beveled, as at thirty degrees to the
vertical. The radiussing and
beveling expands, by more than 300%, the surface area of those vents at the
general upper surface
3302, relative to the surface area which the vents define at the general lower
surface 3312.
[0128] The embodiment shown in FIGURES 35 ¨ 36B is similar to the embodiment
shown in
FIGURES 33 ¨ 34C, with the exception that the elongate ribs provided to
reinforce the drainage
vents 3306 ¨ 3310 are now transverse to the vents 3306 ¨ 3310 rather than
parallel to them. Similar
to previously disclosed embodiments, the tile 3500 has sixteen square portions
3502, each of which
has drainage vents and supporting ribs. The supporting ribs are molded with
the tile body 3506 and
depend from a general lower surface 3505 of the tile body 3506. In each
portion 3502, a long
central rib 3504 is molded to extend completely across drainage vents 3310,
3308 and 3306.
Spaced apart from and disposed in parallel to rib 3504 are two, flanking,
shorter ribs 3508, each of
which span vents 3308 and 3306. Even shorter ribs 3510 are disposed adjacent
to and in parallel to
respective ribs 3508, so as to be opposed to long rib 3504. Ribs 3510 span the
central vent 3306
only. As so disposed, the ribs 3504 ¨ 3510 resist tensile and shear forces
across the longer sides
3512 of the vents 3306 ¨ 3310; they resist any tendency for these vents 3306 ¨
3310 to be opened or
for their longer sides 3512 to be pulled apart from each other. Forces like
this might occur if a load
is placed on top of the tile 3500 on one side of a particular drainage vent,
but not on the other.
[0129] FIGURE 37 illustrates successive steps in a design and manufacturing
method which will
produce the vented floor tiles shown in FIGURES 33 ¨ 36. At step 3700, the
designer determines
where the gates and the corresponding fill points will be on the tile. Once
these locations are
known, at step 3702 the vents can be added to the design. The elongate vents
are arranged in
groups around respective gates/fill points, so that they will be substantially
radiant to those fill
38
CA 02831266 2015-06-09
points; that is, their axes of elongation will be more in alignment with
respective radii from that fill
point than they will be transverse to them. At step 3704, and in the completed
mold, molten
polymer is flowed through the gates and around the structures which will make
the drainage vents.
Because these drainage vents are disposed to be substantially radiant to the
fill points, the
impedance to the molten polymer as it flows by and around the vent-making
structures will be
minimized.
[0130] While embodiments of the present invention have been described in the
above detailed
description and illustrated in the appended drawings, the scope of the claims
should not be limited
by the preferred embodiments set forth in the examples, but should be given
the broadest
interpretation consistent with the description as a whole.
39
