Note: Descriptions are shown in the official language in which they were submitted.
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DISK WHEEL WITH RESILIENT BEARING SUPPORT
AND RIGID ANNULAR TREAD MOUNTING SURFACE
FIELD OF THE INVENTION
This invention relates to a wheel construction
and, more particularly, relates to a wheel construction
wherein the axis of the preassembled bearing housing is
housed in a resilient cylindrical sleeve resiliently
supported at the center of the wheel to thereby
isolate the bearings from shock loads applied to the
wheel and wherein an annular tread made of a moldable
synthetic resin material is lnjection molded onto a0 rigid moldable synthetic resin tread mountiny surface.
BACKGROUND OF THE INVENTION
Wheel constructions are known in which a hub is
constructed of a rigid moldable synthetic resin, and
which has bonded around the outer peripheral surface
thereof an annular tread made from a relatively
softer moldabie synthetic resin. An example of such
construction is disclosed in Canadian Patent No.
992 585, The wheel construction illustrated in
my aforementioned patent has proven to be quite
satisfactory but for a limited market. Customers
purchasing wheels desire the wheel to have a particular
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appearance characteristic to blend with the structure
on which the wheel is to be mounted. Some customers
desire the wheel to take on the appearance of a
sturdy steel wheel and yet other customers desire the
wheel to have the appearance oE a hard rubber wheel.
Steel appearing wheels are good in some areas of use
but where corrosive agents are utilized in the adjacent
environment, steel will rust and become unsightly.
Thus, and in order to enhance the salability of wheel
constructions and still meet the customers' demands,
it is highly desirable to provide a structure which
will permit the assembly of wheel constructions having
the desired aesthetic value to the customer without
having to resort to different methods of construction
for these wheels.
Accordingly, the objects and purposes of this in-
vention include:
1. The provision of a wheel construction having
the known advantages and performance characteristics
resulting from a tread made of a moldable synthetic
resin being injection molded onto a hub of a rigid
synthetic resin, but not limited in appearance to one
particular type of material.
2. The provision of a wheel construction, as
aforesaid, which will permit me to utilize the same
bearing construction that I have used in some of my
earlier developments shown in Canadian Patent Nos.
989 455 and 1 068 457.
3. To provide a wheel construction, as aforesaid,
which is particularly adaptable for use in the wheels
of a caster or the like wherein the treatment received
by the bearing assembly, even under normal conditions
of use, is severe by any reasonable standard.
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4. To provide a wheel construction, as aforesaid,
which has a sufficient structural simplicity that it
can be assembled rapidly, accurately and inexpensively.
5. To provide a wheel construction, as aforesaid,
comprised of a minimum number of parts, each part
being of such structural configuration that it is
capable of being assembled so that -the strength of the
assembly is increased during the assembly.
SUM~RY OF THE INVENTION
In general, the objects and purposes of the in-
vention are met by providing a wheel construction
having a rigid circular disk having means thereon
defining a hole in the approximate center thereof.
Bearing means with a resilient sleevelike housing are
resiliently supported in the hole to facilitate a
rotation of the disk about a defined axis of rotation.
An annulus of moldable synthetic resin material is
fixedly secured to the peripheral surface of the disk.
The annulus has a rigid characteristic and a peripheral
surface thereon defining a tread mounting surface.
An annular tread made of molda~le synthetic resin
material is fixedly secured to the tread mounting
surface. The tread has an outer diameter that is
concentric with the axis of rotation.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and purposes of the invention will
be apparent to persons acquainted with wheel con-
structions of this general type upon reading the
following specification and inspecting the accompanying
drawings, in which:
Figure 1 is a side elevational view of a wheel
embodying my invention;
Figure 2 is a sectional view taken along the line
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II-II of Figure l; and
Figure 3 is a fragmentary central sectional view
taken through a modified wheel construction.
Certain terminology will be used in the following
description for convenience in reference only and will
not be limiting. The words "in" and "out" will
refer to directions toward and away from, respec-tively,
the geometric center of the device and designated
parts thereof. Such terminology will include the
words above specifically mentioned, derivatives thereof
and words of similar import.
DETAILED DESCRIPTION
One embodiment of my invention is illustrated in
Figures 1 and 2. This wheel construction 10 includes
a pair of identical metal disklike stampings 11 and 12.
For purposes of discussion, the structure of the disk
11 will be described below. The corresponding structure
of the disk 12 is identical to the structure associated
with the disk 11, but each of the reference numerals
used for the disk 11 will be utilized also for the
corresponding parts of the disk 12 but will have the
suffix "A" added thereto. The disklike stamping 11
includes a cup-shaped section 13 having an end wall 14
with a central opening 16 therethrough connected to
a cylindrical wall segment 17 connected to the bottom
wall 14 throuyh a rounded corner construction 18. The
cylindrical wall segment 17 is connected through an
inclined wall segment 19 to a generally flat and
radially extending wall segment 21. The outer periphery
of the wall segment 21 is connected to an axially
extending flange radially aligned with the wall segment
17 terminating in a radially outwardly extending tip
23. The various segments of the disks are the same but
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are oriented in a mirror-imagelike manner so that the
innermost surfaces 24 and 24A of the wall segments 21 and
21A engage each other along a parting plane and the in-
clined wall segments 19 and l9A and the cylindrical wall
segments 17 and 17A extend away from each other to axi-
ally space the end walls 14 and 14A from each other.
The holes 16 and 16A in the end walls 14 and 14A,
respectively, are axially aligned. In addition, the cup-
shaped sections 13 and 13A define a housing for a bearing
construction 26. This bearing construction is identical
to the bearing construction shown in aforementioned
Patent Nos. 989 455 and 1 068 457. Thus, a further de-
tailed discussion of my bearing structure appears to be
unnecessary. It should be stated, however, that my bear-
ing construction 26 is housed within a resilient elasto-
meric sleeve 27 having a hardness in the range of 75 Shore
A to 55 Shore D Durometer, preferably 55 Shore D Durometer.
The pair of disks 11 and 12 are held together so that
surfaces 24 and 24A are in engagement with each other
solely by an annulus of moldable synthetic resin material,
particularly acrylonitrile-butadiene-styrene 28. This
material is very rigid and is applied around the periphery
of the disks by an injection molding process. That is,
the disks 11 and 12 are placed into a molding die with the
bearing construction 26 mounted within the cup-shaped
sections 13 and~13A. When the mold closes, the disks 11
and 12 are tightly held together so that the surfaces 24
and 24A engage each other and the annulus 28 is injection
molded around the periphery of the disks 11 and 12. More
specifically, the portions 28A of the material of the
annulus extend radially inwardly around the axially facing
sides of the tips 23 and 23A to a terminal location
radially inwardly of the most axially outwardly portion
of the tips 23 and 23A as shown in Figure 2. Upon a
solidifying of the annulus 28, the disks 11 and 12 are
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fixedly held together and no other mechanical connection
is required to hold the disks 11 and 12 together.
The radial periphery 29 of the annulus 28 defines a
tread mounting surface, An annulus of moldable
synthetic resin tread material, particularly poly-
urethane, defines the tread 31. As has been explained
in Patent No. 992 585, -there is an affinity of poly-
urethane to acrylonitrile-butadiene-styrene material
especially when the polyurethane is injection molded
onto the hardened acrylonitrile-butadiene-styrene
surface. As a result of the foregoing construction,
I have been able to utilize the technology developed
and covered in Patent No. 992 585 but with a wheel
construction utilizing steel disks 11 and 12 and
further utilizing my known and widely accepted
bearing construction 26. In addition, the method
of assembly of the wheel by placing the parts into
a mold structure assures that the periphery of the
treadstock 31 is precisely concentric about the
axis of rotation defined by the central axis of the
bearing construction 26. Further, the resilient
characteristic of the sleeve 27, which sleeve separates
the bearing races from the material of the disks 11
and 12, effects an isolation of the bearings from
shock loads applied to the wheelO
~ eferring now to Figure 3, some customers prefer
the wheel construction to have the appearance of a
hard rubber tire. In the embodiment of Figure 3, I
use a hard rubber material 32 which is joined to the
bearing construction 26 by injection molding a ~uantity
of moldable synthetic resin material 33 between the
inner surface 34 of a central hole in the rubber
material 32 and the outer peripheral surface 36 of the
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elastomeric sleeve 27 in the bearing construction 26.
This method of assembly and related structure are
disclosed in aforementioned Patent No. 1 068 457.
Accordingly, further discussion about this construction
appears unnecessary.
A facet of the construction of the embodiment in
Figure 3 is that hard rubber is incompatible with
acrylonitrile-butadiene-styrene and there will be no
mutual adherence of the acrylonitrile-butadiene-
styrene material to the peripheral surface 37 of thehard rubber disk 32. Therefore, I provide a pair of
oppositely axially opening annular grooves 38 adjacent - -
the periphery of the hard rubber disk 32. I then in-
jection mold an annulus 39 of acrylonitrile-butadiene-
styrene material around the periphery of the hard
rubber disk 32. Since acrylonitrile-butadiene-styrene
material has a very rigid characteristic, the portion
41 of the acrylonitrile-butadiene-styrene material
in the grooves 38 effects a mechanical coupling of the
annulus 39 to the periphery of the hard rubber disk
32. I thereafter injection mold a treadstock 42
around the periphery of the hardened annulus 39. As
in the preceding embodiment, the treadstock is
made of a polyurethane material. Thus, when the poly-
urethane material forming the treadstock is injection
molded around the periphery of the annulus 39, the
polyurethane will, as in the preceding described
embodiment, substantially completely encase the
periphery of the annulus 39 in such close and intlmate
contact that a fusion bonding occurs between the annulus
39 and the treadsiock 42 to thereby firmly and securely
lock the treadstock to the annulus 39.
Thus, and due to the construction in the embodiment
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illust.rated in Figure 3, I can provide a structure having
the appearance of a hard rubber tire to customers
desiring this form of construction and appearance rather
than the appearance of rne-tal and with li-ttle, if any,
change in -the manufacturing technique.
Although particular preferred embodiments of the
invention have been disclosed in detail for illustrative
purposes, it will be recognized that variations or
modifications of the disclosed appara-tus, including the
rearrangement of parts, lie within the scope of the
present invention.
