SOLID-TIRE-AND-HUB ASSEMBLY
FIELD OF INVENTION
[000 l] The subject matter disclosed herein relates generally to the field of tires and,
5 more particularly, to solid-tire-and-hub assemblies implemented with cargo-related
applications.
BACKGROUND
[0002] A solid (non-pneumatic) or flat-free tire generally is puncture-resistant and does
not blowout under high loads, which makes it suitable for slow-moving industrial cargo
10 applications that require heavy lifting. As such, this type of tire is typically implemented and
functions as a conveyor wheel or drive roller in power-drive units (PDUs), transmission devices,
forklifts, hand trucks, medical-mobility equipment, lawn mowers, automobiles, freighter
common turntables for aircraft, etc.
[0003] A two- or three-inch cargo PDU tire, for example, experiences a vertically
15 downward-acting load and a traction load acting on a cross-section of the tire. The vertical load
mainly contributes to high strain at a location of an edge of the tire (referred to hereinafter
merely as "the edge strain") while the traction load ~llainlyc ontributes to high strain on a center
of the tire (referred to hereinafter merely as "the center strain"). These strains together are
dictated by design of an assembly of both the tire and a corresponding hub. For such a design,
20 the strains are inversely proportionate to each other subject to changing thickness of the
assembly. More specifically, while one strain increases, the other decreases and vice versa. In
this way, it is not possible to decrease, for instance, the edge strain without affecting the center
strain.
BRIEF DESCRIPTION OF INVENTION
25 [0004] According to a non-limiting exemplary embodiment of the invention, a solidtire-
and-hub assembly is provided. The assembly includes a solid lire defining a pair of
opposed, spaced side surfaces and a pair of opposed, spaced facial surfaces extending
between the side surfaces such that the solid tire defines a substantially trapezoidal transverse
cross-section. The solid tire is disposed about a partially hollow hub, which defines a
substantially "I" transverse cross-section substantially aligned with the cross-section of the
solid tire, an axial aperture configured to receive a drive shaft, and a plurality of holes defined
about the aperture.
[0005] In aspects of the embodiment, an interior outer portion of each of the side
5 surfaces of the solid tire is arcuate such that the interior outer portions are concave with
respect to the hub. The facial surfaces of the solid tire include an exterior facial surface
extending between corresponding exterior edges of the side surfaces and being substantially
planar in the cross-section. An interior facial surface extends between corresponding interior
edges of the side surfaces and is arcuate and substantially concave with respect to the exterior
10 facial surface and in contacting relationship with the hub.
[0006] In a further aspect, a maximum thickness of the solid tire through the crosssections
is about 4.4 mtn.
[0007] In a further aspect, a radius of curvature of the interior outer portion of each of
the side surfaces of the solid tire is about 4.0 mm.
15 [OOOS] In a further aspect, an angle from an imaginary chord extending between the
corresponding interior edges of the solid tire to a substantially linear interior central portion
of each side surface is about 54.0 degrees.
[0009] In a further aspect, an arc radius of the interior facial surface of the solid tire is
about 90 mm.
20 [OOlO] In f~irther aspects, the hub defines a pair of opposed, spaced, substantially
linear outer side surfaces and a pair of opposed, spaced, substantially linear inner side
surfaces. A11 exterior facial surface extends between cossesponding exterior edges of the
outer side surfaces of the hub and is arcuate and substa~ltially collcave with respect to the
solid tire and in contacting relationship with the interior facial surface of the solid tire. Each
25 of a pair of opposed, spaced interior f'acial surfaces each extends between correspondingly an
exterior edge of the inner side surface to an interior edge of the outer side surface of the hub.
At least one i ~ ~ ~ ~ e rsmurofascte is defined by the aperture.
[OOll] In a further aspect, the aperture and holes extend through a core of the hub.
Loo1 21 Also according to a non-limiting exe~nplary embodiment of the invention, a
power-drive unit is provided. The unit includes a housing, a drive shaft, and at least one of
the solid-tire-and-hub assembly connected to the housing.
[00 131 The solid-tire-and-hub assembly according to the invention defines particular
5 constant and varying profiles or cross-sections through a periphery of the assembly and
respective design features. These profiles and features achieve a significant reduction in the
edge strain of the assembly while keeping the center strain thereof substantially unchanged.
Also, performance of the solid-tire-and-hub assembly is enhanced and highly reliable without
any significant change to a size, shape, or manufacturing process of the assembly. Furthermore,
10 the solid-tire-and-hub assembly is highly durable (i.e., does not crack) such that life tllereof is
extended. In addition, the solid-tire-and-hub assembly allows the tractive load to act on a
larger area of the assembly and, in turn, help to achieve a significant reduction in the offset edge
and center strains.
BRIEF DESCRIPTION OF DRAWING
15 [0014] The subject matter that is regarded as the invention is particularly pointed out
and distinctly claimed in the claims at the conclusion of the specification. The foregoing and
other features and advantages of the invention are apparent from the following detailed
description taken in conjunction with the accompanying drawing in which:
[00 151 FIG. 1 is a diagrammatical top view of a non-limiting cxeinplary elnbodiinent
20 of a power-drive unit (PDU) according to the invention;
[00 1 61 FIG. 2 is a diagrammatical end view of the embodiment of the PDU illustrated
in FIG. 1 ;
[00 1 71 FIG. 3 is a partial transverse cross-sectional view of a non-limiting exen~plary
embodiment of a solid-tire-and-hub assembly of the PDU illustrated in FIGS. 1 and 2
25 according to the invention; and
[00 1 81 FIG. 4 is a partial perspective view of the embodiment of the solid-tire-andhub
assembly illustrated in FIG. 3.
DETAILED DESCRIPTION OF INVENTION
[00 191 The figures show a non-limiting exemplary embodiment of a solid-tire-andhub
assembly according to the invention, generally indicated at 10, configured to be
implemented with, in general, slow-moving industrial cargo applications that require heavy
5 lifting. In this regard, although the assembly I0 is disclosed herein as being implemented and
functioning as a two- or three-inch rubber-coated conveyor wheel or drive roller 10 in an aircraft
power-drive unit (PDU), it should be readily appreciated that the assembly 10 may be any
suitable size and implemented in any suitable type of PDU (aircraft or otherwisej. It should
be readily appreciated also that the assembly 10 may be implemented with any other such
10 applications-including transmission devices, forklifts, hand trucks, medical-mobility
equipment, lawn mowers, and freighter common turntables for aircraft. It should be readily
appreciated also that the assembly 10 may be implemented with any other suitable
applications (e.g., related to automobiles) and cargo-handling systems.
[0020] A cargo aircraft includes a cargo-loading system that, in turn, has a main cargo
15 door through which cargo containers and pallets [collectively known as "unit load devices"
(ULDs)] enter and exit a main cargo deck within a main cargo compartment. Cargo within
the main cargo deck of the aircraft is typically supported by a system of freely rotating floormounted
conveyance rollers. Installed 011 the main cargo deck are a plurality of PDUs. Sets
or banks of the PDUs can be simultaneously elevated from beneath the main cargo deck to a
20 level just above the conveyance rollers. Each PDU may be a separate electro-mechanical
actuator that includes at least one assembly 10. The assemblies 10 of the elevated PDUs
contact and move the cargo above the conveyance rollers in a commanded direction upon
energization of the PDUs. The movement of the cargo depends upoil a coefficient of friction
between the assemblies 10 and a bottom surface of the cargo as well as a lifting force
25 generated by respective lift mechanisms of the PDUs. When the PDlls are de-energized,
rotation of the assemblies 10 ceases, and the cargo stops moving. Several sets of PDUs can
be arranged along a common path of conveyance, and each set can be operated separately,
thereby allowing for trailsfer of multiple pieces of the cargo. Loading personnel can guide
the cargo by a joystick, typically in combination wit11 otller switcl~esb, uttons, and/or similar
30 controls.
loo2 1 1 In the aircraft, most of the PDUs are arranged in rows on either side of a
loi~gitudinalc enterline of the main cargo deck. The ULDs loaded into the aircraft typically
are arranged in two rows, one on either side of the centerline. It should be readily
appreciated that such ULDs on a given side are propelled in a longitudinal direction by the
5 PDUs located on that side. Additional PDUs may be found in an omni-directional area
proximate the main cargo door. It should be readily appreciated that the main cargo deck of a
typical cargo aircraft is also provided with various non-powered rollers, guides, restraints,
and the like.
[0022] In a large cargo aircraft, there may be several dozen PDUs. To control the
10 PDUs, the cargo-loading system is provided with a number of features. Among these are a
controller, (sometimes called a "main controller unit"), main control panel, and plurality of
local control panels-including control panels on a left side of the centerline and right side of
the centerline as the front of the aircraft is laced. During loading and unloading operations,
two- or three-person teams are common.
15 [0023] Referring now to FIGS. 1 and 2, a non-limiting exemplary embodiment of a
PDU accordiilg to the invention is generally indicated at 12. The PDU 12 includes a housing,
generally indicated at 14, that incorporates at least one assembly 10. In an aspect of the
embodiment shown in the figures, the PDU 12 includes a pair of assemblies 10 connected to
the housing 14. The assenlblies 10 are configured to be coupled to a drive shaft 16. The
20 PDU 12 includes also necessary motor and gear assemblies, generally indicated at 18, for
turning and/or raising the solid-tire-and-hub assemblies 10 so that the solid-tire-and-hub
assemblies 10 are positioned above the main cargo deck of the cargo-loading system of the
aircraft and able to contact a bottom of a ULD.
[00241 It should be readily appreciated that the solid-tire-and-hub assembly 10 or
25 assemblies 10, housing 14, drive shaft 16, and motor and gear assemblies 18 can have any
suitable structural relationship with each other. It should be readily appreciated also that the
PDU 12 can incorporate any suitable number of solid-tire-and-hub assemblies 10. It should
be readily appreciated also that the solid-tire-and-hub assembly 10 or assemblies 10 can be
connected to the housing 14 in ally suitable manner. It should be readily appreciated also that
30 each of the housing 14, drive shaft, and motor and gear assemblies 18 can have any suitable
shape, size, and structure and structural relationship with a remainder of the PDU 12. It
should be readily appreciated also that the PDU 12 can include any suitable number of motor
and gear assemblies 18. It should be readily appreciated also that the motor and gear
assemblies 18 can turn and/or raise the solid-tire-and-hub assemblies 10 in ally suitable
manner so that the solid-tire-and-hub assemblies 10 are positioned above the main cargo deck
of the cargo-loading system of the aircraft and able to contact a bottom of a ULD. It should
be readily appreciated also that the PDU 12 can include any other suitable structural elements
as well each of which can have any suitable structural relationship with a remainder of the
PDU 12.
10 [0025] Referring now to FIGS. 3 and 4, each solid-tire-and-hub assembly 10 includes,
in general, a solid tire, generally indicated at 20, and a partially hollow hub, generally
indicated at 22. The tire 20 is disposed about the hub 22, and the hub 22 is configured to
receive the drive shaft 16. The tire 20 defines a pair of opposed, spaced side surfaces 24 and
a pair of opposed, spaced facial surfaces 26 extending between the side surfaces 24 such that
15 the tire 20 defines a substantially trapezoidal transverse cross-section. The hub 22 defines a
substantially "I" transverse cross-section substantially aligned with the cross-section of the
tire 20. The hub 22 defines also an axial aperture 28 configured to receive the drive shaft 16
and a plurality of holes 30 defined about the aperture 28 (FIG. 4 only).
[0026] More specifically, in aspects of the embodiment and referring to FIG. 4, a left
20 half of the assembly 10 is symmetrical with and a mirror image of a right half of the assembly
10, and a top half of the assembly 10 is symmetrical with and a mirror image of a bottom half
of the assembly 10 (when viewing the particular cross-section of the assembly 10 shown in
the figure). In this way, for instance, the "trapezoid" of the cross-section of the tire 20 is
upright at a top of the figure and inverted at a bottom of the figure such that the "trapezoids"
25 are mirror images of each other. Also, the tire 20 is cylindrical and completely solid, and the
hub 22 defines a disk-shaped core, generally indicated at 3 1, that is solid (except for the axial
apcrture 28 and holes 30) and a pair of disk-shaped voids 32 disposed on respective sides of
the core 3 1. In the example shown, the voids 32 define a same width with respect to each
other, and the core 31 is wider than each of the voids 32. IIowcver, it should be readily
30 appreciated that each of the core 31 and voids 32 can have any suitable width such that the
assembly 10 defines any suitable width. It should be readily appreciated that the tire 20 can
disposed about the hub 22 in any suitable manner (such as integrally).
[0027] Referring back to FIGS. 3 and 4, an interior outer portion 33 of each of the
side surfaces 24 of the tire 20 is arcuate such that the interior outer portions 33 are concave
5 with respect to the hub 22. A remainder of each of the side surfaces 24 can be linear or
arcuate. In the example shown, the remainder of each of the side surfaces 24 is substantially
linear.
[0028] The facial surfaces 26 of the tire 20 include an exterior facial surface 26a that
extends between corresponding exterior edges 34 of the side surfaces 24 and is substantially
10 planar in the cross-section. An interior facial surface 26b extends between corresponding
interior edges 36 of the side surfaces 24 and is arcuate and substantially concave with respect
to the exterior facial surface 26a and in contacting relationship with the hub 22. The exterior
facial surface 26a is shorter than the interior facial surface 26b (and the side surfaces 24 are a
same length with respect to each other and shorter than the exterior and interior facial
15 surfaces 26a, 26b).
[0029] In further aspects and as shown in FIG. 3 only, a maximum thickness "T" of
the tire 20 through the cross-sections is about 4.4 mm. Also, a radius of curvature "R" of the
interior outer portion 33 of each of the side surfaces 24 is about 4.0 mm. Furthermore, an
angle "0" from an imaginary chord "C" extending between the interior edges 36 of the tire 20
20 to a corresponding substantially linear interior central portion 38 of each side surface 24 is
about 54.0 degrees. In addition, an arc radius "r" of the interior facial surface 26b is about 90
mm. 'E'hese parameters ("T," "R," "0," and "r") of each profile of the solid-tire-and-hub
assembly 10 can be optimized to achieve optimal results of measurement of strains (according to
acceptable limits thereof).
25 [0030] It should be readily appreciated that each the maximum thickness "T" of the tire
20 through the cross-sections, radius of curvature "R" of the interior outer portioil 33 of each
of the side surfaces 24, angle "0" from the imaginary chord "C" to the corresponding interior
central portion 38 of each side surface 24, and arc radius "r" of the interior facial surface 26b
can be any suitable amount or size.
[003 11 In further aspects, the hub 22 defines a pair of opposed, spaced, substantially
linear outer side surfaces 40 disposed flush with the side surfaces 24 of the tire 20. The hub
defines further a pair of opposed, spaced, substantially linear inner side surfaces 42. The
outer and inner side surfaces 40, 42 of the hub 22 are disposed perpendicular to the exterior
5 facial surface 26a of the tire 20. The inner side surfaces 42 are longer than the outer side
surfaces 40. However, it should be readily appreciated that the outer and inner side surfaces
40,42 and can be any suitable length.
100321 An exterior facial surface 44 extends between corresponding exterior edges 46
of the outer side surfaces 40 of the hub 22. The exterior facial surface 44 of the hub 22 also
10 is arcuate and substantially concave with respect to the tire 20 and in contacting relationship
with the interior facial surface 26b of the tire 20. In a version of this aspect, an entirety of the
exterior facial surface 44 of the hub 22 is in contacting relationship with an entirety of the
interior facial surface 26b of the tire 20. A radius of curvature of the exterior facial surface
44 of the hub 22 [and, in turn, the arc radius "r" of about 90 mm of the interior facial surface
15 26b of the tire 201 is less tight than the radius of curvature "R" of the interior outer portion 33
of each of the side surfaces 24 of the tire 20. However, it should be readily appreciated that
the radius of curvature of the exterior facial surface 44 of the hub 22 can be any suitable
radius.
[0033] A pair of opposed, spaced interior facial surfaces 48 of the hub 22 are defined
20 on respective sides of the core 31 of the hub 22. More specifically, each of the pair of
interior facial surfaces 48 of the hub 22 extends between correspondingly an exterior edge 50
of the inner side surface 42 to an interior edge 52 of the outer side surface 40 of the hub 22.
Each interior facial surface 48 can define at least one tread, groove, or dimple (a tread being
shown in FIG. 4 at 53 extending along an entirety of the interior facial surface 48 and adjacent
25 to the core 3 1). In this regard, it should be readily appreciated that each of the tread(s) 53 can
have any suitable shape, size, and structure and relationship with a remainder of the interior
facial surface 48 and the interior facial surface 48 can define any suitable number of treads
53. The interior facial surfaces 48 are shorter than the exterior facial surface 44 of the hub
22. In the particular cross-section of the hub 22 shown in FIG. 4, the outer side surfaces 40,
30 exterior and interior facial surfaces 44, 48, and a corresponding surface of the core 3 1 define
a substantially rectangular cross-section of the hub 22. Also, a thickness of the hub 22
(minus the core 3 1) is less than the maximum thickness "T" of the tire 20 through the crosssections.
However, it should be readily appreciated that the thickness of the hub 22 (minus
the core 3 1) can be any suitable thickness.
[0034] The aperture 28 extends through the core 31 of the hub 22 (FIG. 4 only). At
5 least one innermost surface 54 is defined by the aperture 28. In the example disclosed, the
aperture 28 is substantially cubical such that four innermost rectangular surfaces 54 are
defined (although only three innermost surfaces 54 are shown). In such case, the aperture 28
is configured to receive a drive shaft 16 defining a rectangular transverse cross-section.
However, it should be readily appreciated that the aperture 28 can be any suitable shape. For
10 example, the aperture 28 can be disk-shaped such that only one innermost ring-shaped
surface 54 is defined. In such case, the aperture 28 would be configured to receive a drive
shaft 16 defining a circular transverse cross-section.
[003 51 The holes 30 extend through the core 3 1 of the hub 22 as well and are identical
with respect to each other and spaced substantially uniformly with respect to each other and
15 circularly about the aperture 28. In the example shown, each hole 30 defines a circular
transverse cross-section and is smaller than the aperture 28. Also in this example, a portion of
each of the holes 30 defines a poi-tion of the coi-sesponding interior facial surface 48 of the hub
22, and the holes 30 are spaced fi-om the apei-ture 28. However, it should be readily
appreciated that each hole 30 can have any suitable shape, size, and relationship with a
20 remainder of the hub 22. It should be readily appreciated also that the hub 22 can define any
suitable number of holes 30.
[003 61 In further aspects, the solid-tire-and-hub assembly 10 defines a two-inch or
three-inch diameter. However, it should be readily appreciated that the assembly 10 can define
any suitable diameter. It should be readily appreciated also that there is no significant change in
25 area among various cross-sections of the assembly 10, which cross-sections are dictated by a
design envelope of the assembly 10. In an aspect, a significant change in such design envelope
is permitted. In this way, a bottom surface (i.e., the exterior facial surface 26a) of the asseinbly
10 can be moved down to enlargen a surface area of the bottom surface 26a, thereby allowiilg a
tractive load to act on a larger area and, in turn, help to achieve a significant reduction in the
30 offset edge and center strains. In fact, geometrical dimensions and scale of the assembly 10
can vary depending upon the nature and size of loads exerted on the tire 20 and particular
applications. Further, the tire 20 is made of any suitable rubber or elastomeric. It should be
readily appreciated, however, that each of the tire 20 and hub 22 can be made of any suitable
material.
5 [0037] The assembly 10 defines particular constant and varying profiles or crosssections
through a periphery of the assembly 10 and respective design features. These profiles
and features achieve a significant reduction in the edge strain of the assembly 10 while keeping
the center strain of the assembly 10 substantially unchanged. Also, performance of the
assembly 10 is enhanced and highly reliable without any significant change to a size, shape, or
10 manufacturing process of the assembly 10. Furthermore, the assembly 10 is highly durable
(i.e., does not crack) such that life of the assembly 10 is extended. In addition, the assembly
10 allows the tractive load to act on a larger area of the assembly 10 and, in turn, help to achieve
a significant reduction in the offset edge and center strains.
[003 81 While the invention has been described in detail in connection with only a
15 limited number of embodiments, it should be readily appreciated that the invention is not
limited to such disclosed embodiments. Rather, the invention call be modified to incorporate
any number of variations, alterations, substitutions, or equivalent arrangements not heretofore
described, but which are commensurate with the spirit and scope of the invention.
Additionally, while various non-limiting embodiments of the invention have been described,
20 it should be readily appreciated that aspects of the invention may include only some of the
described embodiments. Accordingly, the invention is not to be seen as limited by the
foregoing description, but is only limited by the scope of the appended claims.
We claim:
I. A solid-tire-and-hub assembly comprising:
a solid tire defining a pair of opposed, spaced side surfaces and a pair of opposed,
spaced facial surfaces extending between the side surfaces such that the solid tire defines a
5 substantially trapezoidal transverse cross-section; and
a partially hollow hub about which the solid tire is disposed and defining a
substantially "I" transverse cross-section substantially aligned with the cross-section of the
solid tire, an axial aperture configured to receive a drive shaft, and a plurality of holes defined
about the aperture.
2. The solid-tire-and-hub assembly of claim 1, wherein an interior outer portion
of each of the side surfaces of the solid tire is arcuate such that the interior outer portions are
concave with respect to the hub and the facial surfaces of the solid tire include an exterior
facial surface extending between corresponding exterior edges of the side surfaces and being
15 substantially planar in the cross-section and an interior facial surface extending between
corresponding interior edges of the side surfaces and being arcuate and substantially concave
with respect to the exterior facial surface and in contacting relationship with the hub.
3. The solid-tire-and-hub assembly of claim I, wherein a maximum thickness of
20 the solid tire through the cross-sections is about 4.4 mm.
4. 'I'hc solid-tire-and-hub assembly of claim 2, wherein a radius of curvature of
the interior outer portion of each of the side surfaces of the solid tire is about 4.0 mm.
25 5. The solid-tire-and-hub assembly of claim 2, wherein an angle from an
imaginary cl~ord extending between the corresponding interior edges of the solid tire to a
substantially linear interior central portion of each side surface is about 54.0 degrees.
6. The solid-tire-and-hub assembly of claim 2, wherein an arc radius of the
interior facial surface of the solid tire is about 90mm.
7. The solid-tire-and-hub assembly of claim 2, wherein the hub defines:
a pair of opposed, spaced, substantially linear outer side surfaces;
a pair of opposed, spaced, substantially linear inner side surfaces;
a11 exterior facial surface extending between corresponding exterior edges of the outer
side surfaces of the hub and being arcuate and substantially concave with respect to the solid
tire and in contacting relationship with the interior facial surface of the solid tire;
a pair of opposed, spaced interior facial surfaces each of which extends between
correspondingly an exterior edge of the inner side surface to an interior edge of the outer side
surface of the hub; and
at least one innermost surface defined by the aperture.
8. The solid-tire-and-hub assembly of claim 7, wherein the aperture and holes
extend through a core of the hub.
9. A power-drive unit comprising:
a housing;
a drive shaft; and
at least one solid-tire-and-hub assembly conilected to the housing and including:
a solid tire defining a pair of opposed, spaced side surfaces and a pair of
opposed, spaced facial surfaces extending between the side surfaces such that the
solid tire defines a substantially trapezoidal transverse cross-section; and
a partially hollow hub about which the solid tire is disposed and defining a
substal~tially "I" trailsverse cross-section substantially aligned with the cross-section
of the solid tire, an axial aperture configured to receive a drive shaft, and a plurality of
holes defined about the aperture.
10. The power-drive unit of claim 9, wherein an interior outer portion of each of
5 the side surfaces of the solid tire is arcuate such that the interior outer portions are concave
with respect to the hub and the facial surfaces of the solid tire include an exterior facial
surface extending between corresponding exterior edges of the side surfaces and being
substantially planar in the cross-section and an interior facial surface extending between
corresponding interior edges of the side surfaces and being arcuate and substantially concave
10 with respect to the exterior facial surface and in contacting relationship with the hub.
11, The power-drive unit of claim 9, wherein a maximum thickness of the solid
tire through the cross-section is about 4.4 mm.
12. The power-drive unit of claim 10, wherein a radius of curvature of the interior
outer portion of each of the side surfaces of the solid tire is about 4.0 mm.
13. The power-drive unit of claim 10, wherein an angle from an imaginary chord
extending between the corresponding interior edges of the solid tire to a substantially linear
20 interior central portion of each side surface is about 54.0 degrees.
14. The power-drive unit of claim 10, wherein an arc radius of the interior facial
surface of the solid tire is about 90 mm.
15. The power-drive unit of claim 10, wherein the hub defines:
a pair of opposed, spaced, substantially linear outer side surfaces;
a pair of opposed, spaced, substantially linear inner side surfaces;
an exterior facial surface extending between corresponding exterior edges of the outer
side surfaces of the hub and being arcuate and substantially concave with respect to the solid
tire and in contacting relationship with the interior facial surface of the solid tire;
a pair of opposed, spaced interior facial surfaces each of which extends between
5 correspondingly an exterior edge of the inner side surface to an interior edge of the outer side
surface of the hub; and
at least one innermost surface defined by the aperture.