Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to apparatus for
forming a tread on a tire, and more particularly, to
apparatus wherein tread-forming shoes Eorm a tread on
rubber material.
In the formation of a tread on a tire, upper
and lower mold portions are provided, each mold portion
containing means defining a tread pattern. In one
known embodiment, each mold portion contains a rigidly
mounted solid ring, which defines the tread pattern,
and in another known apparatus, each mold portion
contains a resiliently mounted segmented ring (i.e.,
individual tread shoes). In both systems, it is
common practice to initially completely close the two
mold portions together, and then to apply fluid pressure
to the tire to force the rubber into contact with the
tread-forming shoes. The segmented ring design as
described above is considered to have a certain advantage
oyer the rigidly mounted solid ring system, since when
the mold portions are moved apart to allow removal of
the tire, the resilientl~ mounted shoes move radially
outwardly some distance greater than the tread groove
depth so that the tire can be removed from the apparatus
without distorting the tread.
Since in such conventional systems the tire
is inflated and expanded to force the rubber into the
tread-forming means, the expansion and forces involved
in forming the tread tend to displace radial and
circumferential reinforcements from their ideal
; positions.
It will be understood that it would be
considered advantageous for the tread to be formed on
the tire with the tire structure remaining in its ideal
position during the formation thereof through isolation
of the forces of the re;nforcement of -the tire.
It will also be understood that, while achieving
proper forlllation of the tread, the method thereof, and
the apparatus for acl-ieving such method, should, wi-th
advantage, be extremely simple and efficient.
In our Application ~o. 282,~59 from which the
present application is divided, we describe and claim a
method of forming a tread pattern on a tire, the method
comprising moulding an elastomeric material between a
mold body and tread-forming shoes, moving the shoes
outwardly away from the body ~ith the elastomer adhering .-
thereto, removing the mold body and replacing it by a
tire carcass, and then moving the shoes inwardly to
mold the elastomer onto the tire carcass, the outwards
and inwards movement relative to the mold body or tire
carcass respectively including a radial component of
movement.
According to one aspect of the invention there is
provided a mold body on which elastomeric material can be
positioned for formation of a tread thereon comprising a
generally annular main body pOrtiOTI and a continuous rib
disposed about the outer periphery of the main body portion
including a plurality of poppet valve members movably
mounted thereon and movable between retracted positions ~ :
relative to the main body portion and extended positions
relative to the main body portion; and means for selectively
extending and retracting the poppet valve members.
2-
.,
These ancl other features. of the invention will become
apparent from a study O r the following specification and
drawing in which:
FIG. I is a front elevation of an overall apparatus
incorporating the invention;
FIG. 2 is a sicle elevation of the apparatus shown in
F:[G. l;
FIG. 3 is a section view of the main portion of the
apparatus of FIGS. 1 and 2;
FIG. 4 is a plan view of the body for use with the
apparatus of FIG. 3;
FIG. 5 is a sectional view taken along the line V-V
o:E FIG. 4;
FIG. 6 is a sectional view taken along the line VI--VI
of FIG. 4;
FIG. 7 ls a sectional view taken along the line
VII-VII of FIG. 4;
FIG. 8 is a sectional view taken along the ].ine VIII-
; VIII of FIG. 4;
FIG. 9 is a sectional view taken along the line
IX-IX of FIG. 4;
FIGS. 10-15 are schematic views of the apparatus
showing the operation thereof;
FIG. 16 is a view similar to that shown in FIG. 9J
but of an alternate embodiment of body; ..
FIGS. 17-19 are schematic views of an alternate
embodiment of apparatus showing the operation thereof; and
-3-
. - " ' . :
, ~
. .
FIG. 20 is a schematic view of yet
another embodiment of the apparatus showing the
operation thereof.
Descri~tion of the Preferred Embodiment
.,. _. _.... _ _~ ~..___... _ . _ _._. _ __._.____
Shown in FIGS. 1 and 2 is the overall
apparatus 20 incorporating the invention. As
shown therein, a beam structure 22 has fixed
thereto the body 24 of a cylinder 26, with the rod
end 28 thereof extending downwardl~ therefrom.
The rod end 28 has fixed thereto ~ plate members
30,32 having respective eyes 34 mounted thereto.
A first or upper member 36 has eyes 38 mounted to
the upper surface 40 thereof, and chains 42
interconnect the eyes 34 and eyes 38 as shown in
FIGS. 1 and 2. It is to be understood that through
extension and retraction of the rod 28 of the
cylinder 26, the plate members 30,32 are lowered
and raised to lower and raise the upper member 36.
~ lower member 44 is mounted to a frame
46 whiGh in turn rests on the floor. Details of
the upper and lower members 36, 44 are best shown
in FIG. 3.
A5 shown in such ~IG. 3, the lower
member 44 defines an annular recess 46, the outer
surface 48 of which is angled downwardly and
inwardly of the member to define a ramp surface.
In contact with such ramp surface 48 are six
tread-forming shoes~50, spaced about the annular
recess 46. The upper member 36 also defines an
annular recess 52, with the outer ramp surface 54
thereof tapered upwardly and inwardly of the membe~ 36
as shown in FI~. 3, and further included are six tread-
form~ng shoes 56 positioned in contact with the ramp
surface 54, and spaced about the annular recess 52 of
the member 36. The tread-forming shoes 56 are retained
for sliding movement along the ramp surface 54 by means
of angled bolt structures 58. Each bolt structure 58
includes a bolt 59 disposed through a stepped bore 60
defined by a shoe 56, and having the end thereof in
threaded engagement with the member 36. A sleeve 61 is
disposed about the bolt 59, in contact with the member
36 and extending to the step 65 in the bore 60. A
washer 67 rests on the step 65 and the sleeve 61,
forced therecn by the head 6~ of the bolt 59. The
tread-~orming shoes 50 are also mounted to the member
44 in the same manner. It will be seen that through
such mounting of the tread-forming shoes 56 to the member
36, the tread-forming shoes 56 are movable to outward,
extended positions relative to the member 36,
2Q and inwa~d, retracted positions relative to the member
: 36. Similarly, the tread-~orming shoes 50 are movable
. to outward, extended positions relative to the member
44, and inward, retracted positions relative to the
member 44.
~ esilient springs 62 interconnect the member
44 and tread-forming shoes 50 for xesiliently biasing
the tread-forming ~hoes 5Q in their ou~ward, extended
positions. Si~ilarl~, res~lient springs 64 interconnect
; the membex 36 and txead-foxming shoes 56 in the outward
3Q extended positions thexeof.
0J~
As shown in FIG. 3, each of the tread shoes
50 defines a recess 66 which may be generally aligned
with an opening 68 in the member 44 upon movement of
tread shoes 50 from their outward, extended positions
toward the inward, retracted positions thereof. Upon
such general alignment of the recess 66 and opening 68,
an elongated shaft 70 in the form of a bolt may be
positioned through each generally aligned opening 68
and 66, whereby the tread-forming shoes 50 are limited
in movement under the urging of the springs 62 toward
the outer, extended positions thereof, to positions
between the outward, extended and inward, retracted
positions thereof. The tread-forming shoes 56 and
member 36 include a similar structure so selectively
limiting the movement of the tread-forming shoes 56
under the urging of the resilient springs 64 toward the
outward, extended positions thereof~
A body 72 for use with the structure as thus
far described is shown in FIGS. 4-9. As shown therein
the body 72 is made up of a disc 73 (FIG. 5) having
portions 75, 77 fixed to the opposite sides thereof.
Two circular rings 79, 81 are resiliently mounted to
opposite sides of the disc 73. The rings 79, 81 and
outer portion of the disc 73 define a rib 76. The body
72 is thus made up of a generally annular main body
portion 7~, and a rib 76 positioned about the outer
periphery of the generally annular main body portion
74. Fixed to the outer periphery of the rib are ears
78, positioned on opposite sides of the body 72. The
utility of such ears 78 Will be described in detail
further onO
~ J~ JY~
As best shown in FIG. 5, the body 72
defines a passage 80 extending from the outer
periphery of the rib 76 to inside the body 72,
communicating with an annular passage 82 defined
within the body 72. Yet another annular passage
84 is defined by the body 72, and the two annular
passages 82, 84 are connected by a cross passage
86. The annular passage 84 r as shown in FIG. 6,
,4~ C O h~ I' C ~ e~S
t ~ 6~mmwm~ed with yet another passage 88 extending
to the outer periphery of the rib 76.
It will be seen that cooling liquid can
be introduced into the passage 80, to circulate
about and through annular passage 82, through
cross passage 86, into annular passage 84, and
from the annular passage 84 through the passage
88.
As best shown in FIGS. 7 and 9, yet
another passage 90 extends from the outer periphery
of the rib 76 to a third, smaller annular passage
92 defined by the body 72. The body 72 has movably
mounted thereto a plurality of poppet valve members
94, each resiliently biased by a spring 96 into a
position wherein the outer head surface 98 thereof
is generally flush with the outer surface 100 of
the main body portion 74, i.e., with the valve
members 94 in their retracted positions. The
valve members 94 are movable agalnst the resilience
of the springs 96 to extended positions wherein
the outer head surfaces 98 thereof are extended
30~ from the surface 100 of the main body portion 74.
--7--
7~
Each of the poppet valve members 94 is movable in
a chamber 102, a portion of which is defined by a
portion of the inner head surface 104 of the
poppet valve member 94, and each such chamber 102
communicates with -the annular passage 92 through a
passage 106. It will be seen that application of
pressurized air to the passage 90 results in the
fact that pressurized air is communicated to the
annular passage 92, through the passages 106, and
into the chambers 102 to move the valve members 94
to extended positions, wherein the outer head
surfaces 98 thereof are extended from the surface
100 of the main body portion 74.
Yet another passage 108 (FIG. 4), similar
to passage 80, but communicating with another
internal annular passage 110 defined by the body
72, is used in a similar manner to actuate another
plurality of poppet valve members 112 in the same
.anner.
Fixed to the lower surface 113 of the
member 44 are the bodies 114 of a plurality of
cylinders 116 (FIG~. 1 and 2), the rods 118 of
~hich extend through flange portions 120, 122,
defined by the member 44 and beyond the upper
surface 124 thereof. Each rod 11$ has secured
thereto an elongated locking lug 126 which may be
positioned, by turning of the rod 118 about the
longitudinal axis thereof, through a respective
elongated opening 128 defined by a flange 130 of
the member 36. It will be seen that upon relative
movement of the members 36, 44 together (FIGS. 1
and 2), the properly positioned locking lugs 126
are allowed to pass through the respective openings
128 in the flange 130. Then the individual locking
lugs 126 may be turned to an extent so that upon
the downward movement of the rods 118 of the
cylinders 116, the locking lugs 126 contact portions
of the upper surface 132 of the flange 130 to draw
the members 36, 44 together with relatively great
force. The cylinders 116 may, of course, be actuated
in a well known manner, for example, being set up
as slave cylirlders responsive to actuation of a
master cylinder (not shown).
In the use of the apparatus, the body 72
is lifted by means of a fork lift truck (not
shown), the arms of the fork being in contact with
the undersides of ~he ears 78 for proper transport
- thereo~. The body 72 is moved to an oven and
uncured rubbex material is disposed in two strips
134, 136 about the body, the rubber being positioned
on the main body portion 74 adjacent one and the
other sides 1~0, 138 of the rib 76 (see FIC. 10~.
The fork lift truck then moves the body 72 with
the rubber 134, 136 thereon to adjacent the uppex
and lower m.embers 36, 44. The fork lift truck
then deposits the body 72 onto the member 44.
During this time, the tread~forming shoes 5Q, 56
. ~re in their fully extended positions, and are
being heated by application of heated fluid through
: 30 passage means defined by the members 36, 44. The
~ ~J~
rib 76 is positioned so that one side 140 thereof is in
contact with the txead-foxming shoes 5Q (see FIG. 10).
The fork lift truck is then ~emoved from the area of
the members 36, 44. The member 36 is lowered relative
to the member 44 by means of cylinder 26, so that the
locking lugs 126 pass through the apertures 128. The
locking lugs 126 are then rotated to be in position so
that retraction of the rods 118 of the cylinders 116
will draw the member 36 to the member 44. ~uring such
downward movement of the member 36, the tread-forming
shoes 56 have been brought into contact with the other
; side 138 of the rib 75.
The cylinders 116 are then actuated to move
the member 36 toward the member 44 (FIG. 11), the
cylinder 26, of course, being extended sufficiently to
allow enough slack in the chains 42 for such further
drawing down of the member 36. Upon such further
movement of the member 36, with the tread-forming shoes
5Ql 56 in contact with the opposite sides 14Q, 138 of
2Q the rib 76, it will be seen that further movement of
the members 36, 44 together provides a relatlve movement
of tke tread-forming shoes 50, 56 and bod~ 72 such that
the tre~d-forming shoes 50, 56 move along the surfaces
of the sideS 140, 138 of the body 72 into contact with
the rubber material 134, 136 on the body 72 wlth
such relative ~ove~ent being determined b~ the
configurations of the sides 140, 138. Thereby,
the txead-foxming shoes 50, 56 are brought into
--10--
~~ 7
contact with the rubber material 134, 136. That
is, the movement of the tread-forming shoes 50, 56
and body 72 relatively takes place as if the body
72 were being held in a position, and the shoes
50, 56 were being slid along the sides 140, 138 of
the rib 76, so that proper formation of the tread
on the rubber material 134, 136 is provided.
During this process, cooling fluid is
introduced into the passage 80 to flow through the
annular passages 82, 84 and from the body 72 to
provide a proper operating temperature of the body
.~ 72. Since the tread-forming shoes 50, 56 are in a
heated state, the rubber materiall34, 136 will
tend to stick to such shoes rather than the cooled
body 72.
~ lith the members 36, 44 positioned as
shown in FIG. 11, bolts 70 are inserted in the
openings and recesses 68, 66 to limit movement of
the tread-forming shoes 50, 56 under the urging of
2Q the springs 72, 74 toward the outer, extended
positions thereof, to positions between the outward,
; extended and inward, retracted posltions thereof.
The member 36 is moved a small distance from the
member 44, and the tread-forming shoes 50, 56 are
moved toward their outward, extended positions,
being limited by the bolts 70 as described above~
The tread-for~in~ shoes 50, 56 are thereby moved
only a slight distance from the body 72, still in
contact with the rubber matexial 134, 136. At
3Q this point, air is introduced into the passages
~11-
,:, , : ' '
, . . . . . . .
90, 108 to actuate the poppet valve members 94,
112, so that the outer head surfaces thereof
extend beyond the outer surface 100 of the body
portion 74, permitting air to force the rubber
material 13~, 136 from the body 72. It is thereby
insured that the rubber material 134, 136 remains
in contact with the tread-forming shoes 50, 56,
and not in contact with the body 72.
Subsequently, the member 36 is removed
further from the member 44 (FIG. 12)~ and the body
72 is removed from the members 36, 44.
FIG. 13 shows an annular core 150 having
rubber material 152 already deposited thereon
disposed on the member 44. Again, the member 36
is brought to adjacent the member 44 in this case,
until the tread shoes 56 contact the tread shoes
50. At this point, it will be seen that further
relative movement of the members 36, 44 together,
through actuation of the cylinders 116 as above
described, moves the rubber materlal 134, 136 in
contact with the tread-forming shoes 50, 56 into
contact with the rubber material 152 on the annular
core 150 tsee FIG. 14). The uncured rubber material
134, 136 in contact with the tread-forming shoes
50, 56 is brought into contact with the rubber
material 152 positioned on the core 150 through
movement of the -tread--forming shoes 50, 56 toward
the inward, retracted positions thereof. When the
tread-forming shoes have reached the inward retracted
position, the bolts 70 are removed and after
-12-
curing the entire rubber material the member 36 is
then removed from the member 44 as described
above, allowing the tread-forming shoes 50, 56 to
move under the resilience of the springs 62, 64 to
their fully ou~ward, extended positions as shown
in FIG. 15, leaving a tire made up of rubber
material having a tread formed thereon, disposed
on a core 150.
A portion of an alternate embodiment of
body 200 is shown in FIG. 16. As shown therein
the overall construction of the body 200 is gener-
ally similar to the body 72 with particular reference --
to FIG. 9. As shown in FIG. 16, the body 200 is
made of a disc 202 having portions 204, 206 fixed
to opposite sides thereof. This generally makes
up an annular main body portion 208, and movahle
body members 210, 212 in the form of rings are
~ovably mounted to the main ~ody portion 208,
making up with a portion of the disc 202 a rib
209. Resilient elastomeric members 214, 216 are
interposed the rings 210, 212 and disc 202, so
that the rings 210, 212 are resiliently urged away
from the opposite sides of the disc 202. The
inner peripheries 218, 220 of the respective rings
210, 212 are ~uite adjacent the outer surface 221,
223 of the main body portion 208.
The ring 210 defines a plurality of
passages therethrough (one shown at 222~ and
likewise the ring 212 defines a pluxality of
passages therethrough (one shown at 224~. These
-13-
d ~
passages lead Erom adjacent an annular depression
226 defined by the body portion 208 and another
annular depression 228 defined by the body portion
208.
~ dditional rings 232, 234 are movably
mounted to opposite sides of the body 200, resi-
liently urged by spring means 236 to their outward
positions, similar to the previous embodiment of
FIG. 5.
In the use of such apparatus, the tread-
~ forming shoes as previously described bear on the
.~ rings 210, 212, compressing the elastomer.ic members
214, 216 under the force of such shoes, with the
body in the general position shown in, or example,
FIG. 11. In such state, as the tread-forming
shoes form tread on elastomeric material on the
surface 221 of the body 2Q0 and the surface 223 of
the body 200, excess elastomeric material will be
caused to flow under the force of the shoes into
the annular depressions 226, through the passages
222 in the ring 210 and generally from the apparatus.
. Likewise, elastomeric material will flow into the
annular depression 228 and through the passage 224
in the ring 212 and generally from the apparatus.
The rings 232, 234, being in contact with the
shoes, act as dams to retain elastomeric material
. in the propex areas. Thus, it will be seen that
flow o~ elastomeric material during the tread-
~orming operation is allowed for in the embodiment
3Q shown in FIG. 16, so that it is insured that any
-14-
.
.
material forced from the tread-forming areas is
allowed to flow relatively free therefrom.
In the event that too much elastomeric
material has initially been applied to the body
200, the resilience oE the spring means 236 will
be overcome, allowing e~cess elastomeric material
to flow past the edge of the rings 232, 23~.
After insertion of the bolts 70, and
upon the lifting of the member 36 from the member
44 (similar to that shown in FIG. 12), the force
compressing the elastomeric members 214, 216 is
removed from the rings 210, 212, allowing the
rings 210, 21.2 to move to positions wherein communi-
cation is no longer provided between the area 230
of the body 200 and the annular depression 226, or
the area 231 of the body 200 and the annular
depress.ion 228. As the rings 210, 212 move under
the resilience of the elastomeric members 214,
216, the edges of the rings 210, 212 at the inner
peripheries 218, 220 thereof adjacent -the main
body portion 208 act as cutting members to cut off
the elastomeric material which has flowed from the
tread-forming area 230, 231, into the annular
depressions 226, 228 lea~ing elastomeric material
on the body 200 of proper shape and size with
proper tread formed thereon. This cutting operation
is insured during such removal of the member 36
.~ fxom the member 44 since the elastomeric members
214, 216 resiliently bias the rings 210, 212
towards positions blocking ~low of elastomeric
--1.5--
-'~; ,'' ~ , .
.
'7~
material from the areas 230, 231, through the
passages 222, 224.
As yet another alternative,elastcmeric
material need not be init:ially applied to a body
adjacent one and the other sides thereof in accord-
ance with FIGS. 10-11. Rather, as shown in FIG.
17, the body 300 may be provided with a plurality
of upper passages 302, and a plurality of lower
passages 304, all communicating with a main conduit
306 in turn communicating with the head end 308 of
a cylinder 310. In such system, the first and
second members 36, 44 are brought together prior
to the introduction of any elastomeric material on
which tread is to be formed (FIG. 18~, and then
the cylinder 310 is actuated so that elastomeric
material 312 is injected through the conduit 306,
through the passages 302, 304 in the body 300, and
onto the body 300, and into the cavity defined by
the sur~aces of the body 300 and the surfaces of
the tread-forming shoes 50, 56, meanwhile with
such elastomeric material having tread formed
thereon during such operation. The member 36 may
be subsequently removed from the member 44 after
insertion of the bolts 70, as shown in FIG. 19,
whereupon elastomeric material 314, 316 remains on
the shoes 56, and on the shoes 50, in accordance
with the previous embodiment. Subsequent steps in
this method are identical to those shGwn in ~IGS.
13-15.
-16-
,' ' ' , ' , .
~ s yet another embodiment, the member
36' is provided with passages 350, 352 which
communicate with conduits 354, 356 which in turn
communicate with a main conduit 358, communicating
with the head end 360 of a cylinder 362.
Likewise, the member 44' is provided
with passages 36~, 366 which communicate with
conduits 368, 370 which in turn communicate with a
conduit 372 in turn communicating with the head
end 374 of another cylinder 376. The cylinders
362, 376 are filled with elastomeric material 378
which is made to flow into the appropriate tread-
forming areas, through the member 36' and member
4~' with the members 36', 4~' already brought
together, and without the body 72, ha~-ing had
pre~iously applied thereto any elastomeric material.
In yet another method, it will be under-
stood that a portion of the elastomeric material
can be initially applied to the body 72, and the
remaining necessary elastomeric material may be
applied through the method in accordance with
FIGS. 17-l9 or the method in accordance with FIG.
2Q.
While both embodiments described include
a centerparting mold apparatus~ it is to be under-
stood that the parting line of the mold portions
need not be substantially at the center of the
overall apparatus, bu~ can be spaced therefrom,
i.e., the mold apparatus could be of the edgeparting
3Q or shoulder-par-ting type.
-17-
