Abstract:
An outer wheel, tire and rim, is mounted onto an inner wheel or hub and is adapted for low friction rotation on the hub. An arm is pivotally attached to the inner wheel and carries a receiver for the axle upon which the wheel is mounted so that the axle is positionable over an arc of rotation about the pivot point of the arm. The arm is biased by an elastomeric body so that as the arm moves over its arc of rotation, the elastomeric body is compressed. As the wheel rotates under load, road shocks are transferred to the biasing device which acts as a shock absorber.

Description:
This application is a continuation in part (CIP) of a copending utility patent application entitled, “Self-Suspending Wheel,” Ser. No. 09/346,640, having a filing date of Jul. 1, 1999, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to wheel suspensions, and more particularly to a self-suspending wheel with a shock absorbing element contained within the center of the wheel itself. 
     2. Description of Related Art 
     The following art defines the present state of this field: 
     Gagnon, et al., U.S. Pat. No. 5,305,496 describes a caster with two spaced apart wheels with an elastomeric torsional shock and vibration isolating suspension between them. The wheel axis is spaced longitudinally from a bearing axis to subject elastomeric disks positioned between the wheels to torsional shear stresses to help absorb shocks and vibrations. A snubber is provided for limiting the angular motion of the wheels about a bearing axis. 
     Braeger, et al. U.S. Pat. No. 5,394,589 describes three embodiments of a shock-isolating caster. A surface-effect damper engages at least one of a wheel element and an intermediate structural member to dampen vibration and shock loads which would otherwise be transmitted from the wheel element through the intermediate structure and mounting member to the equipment supporting cart. A first embodiment positions the damper between an outer wheel rim and an inner wheel hub. Second and third embodiments mount the wheel on a pivotable arm and dampen the movement of the arm. Capability to adjust damping levels is provided. 
     Kindstrand, et al., U.S. Pat. No. 5,493,755 describes a caster with a stationary hub having a bearing between the hub and a floor engaging wheel ring which allows the wheel ring to rotate relative to the hub. Torsional elastomeric elements mount the hub between spaced support arms radially inward of the bearing and are positioned eccentrically relative to the axis of rotation of the wheel ring so as to suspend the hub resiliently between the arms. In an alternate embodiment, the hub is cantileverd from a single support arm. 
     Lazarevich, et al., U.S. Pat. No. 5,704,621 describes a suspension system for an in-line roller skate in which the suspension system independently controls each wheel of the skate. The suspension system components for each wheel includes a swing arm that is pivotally mounted to a frame attached to a boot of the skate. The wheel is rotatably mounted on a rotation axle between opposing legs of the swing arm. Two C-shaped spring stays are secured to opposing side rails of the frame where one leg of each spring stay travels through a stand-off rigidly secured to one of the opposing legs of the swing arm. A helical spring surrounds the leg of each spring stay between the stand-off and the frame. When the wheel encounters a bump in the ground terrain, the swing arm pivots up and the helical springs are compressed between the stand-off and the frame providing shock absorption. A rebound a stop prevents the swing arm from pivoting too far downward. A jounce stop prevents the swing arm from pivoting too far upward. 
     Gray, U.S. Pat. No. 4,403,784 describes a roller skate formed of a plate with an upper surface to receive a shoe and having a forward and rearward downwardly extending suspension housing, each housing having an opening therethrough, an axle extending through each suspension housing opening having a means at each end for receiving a skate wheel, a first and second elastomeric member received in each suspension housing in spaced apart relationship, each of the elastomeric members having an opening receiving the axle, bolts extending through threaded openings at the top of the suspension housing, the ends of the bolts engaging the upper surfaces of the elastomeric members so that the compressive force applied by the elastomeric members to the axle may be adjusted by threadably positioning the bolts. Another arrangement includes each axle in two portions hinged in the middle so that each roller skate wheel is independently resiliently supported relative to the skate body. 
     Hager, U.S. Pat. No. 4,685,174 describes a shock absorbing caster wheel in which the wheel support bracket is pivotally mounting on a caster bracket and a spring engages the wheel support bracket and caster bracket to absorb shocks on the caster wheel. Vibration dampening pads on the caster bracket slidably engage wall surfaces on the wheel support bracket to dampen oscillation of the wheel support bracket. 
     Burns, U.S. Pat. No. 5,823,543 describes a roller skate shock absorber system in at least two double pivot mechanisms spaced longitudinally from front to back along a skate shoe; a truck device including a plurality of wheels interconnected with the double pivot mechanisms; each of the double pivot mechanisms including a first pivot mounted to the skate shoe, a pivot member rotatably connected to the first pivot and having a second pivot rotatably attached to the truck device; and at least one resilient member dispose between the skate shoe and the truck mechanism for biasing at least one of the pivot mechanisms with its first and second pivots generally vertically aligned to provide a firm push-off force. 
     Hopkins, U.S. Pat. No. 1,185,098 describes a vehicle wheel with a central hub box providing a pair of spaced thrust disks, a hub casing providing conical ends, annular members provided with inclined portions for wedgingly engaging within said conical casing ends, each annular member comprising a bearing flange for engaging the corresponding thrust disk and a cylindrical container, and cushioning members positioned in said cylindrical containers in engagement with said hub box. 
     Bourdeau, U.S. Pat. No. 5,393,078 describes a skate including a chassis formed by an upper horizontal plate solidly joined to the sole of a shoe by fasteners and a lower part running perpendicular to the plate and including at least one lateral flange on which the wheels are disposed by transverse axles solidly joined to the chassis, constituting a rolling train, each of the wheels having a hub in fixed rotation, which is disposed on the axle and which supports a bearing interpolated between the hub and a tire. The hub of the wheel is equipped with an arrangement which allows for its angular deflection relative to its median horizontal plane. The arrangement for angular deflection includes the transverse axle which is horizontally off-center in relation to the virtual center of the wheel which can cooperate by abutment with a fixed axle solidly joined to the chassis which passes through it, and which supports an elastic recoil device. 
     Henschen, U.S. Pat. No. 5,411,287 describes a torsion axle for a vehicle including an elongated axle tube enclosing first stage torsion shafts and second stage torsion shafts all having a common axis, and a metal tube or a non-circular portion of the axle tube and a plurality of resilient rubber rods confine each of the shafts for torsionally resisting rotation of the shaft. Each first stage metal tube is secured to the surrounding axle tube, and each second stage metal tube is connected to the corresponding first stage shaft. A stud projects outwardly from each second stage metal tube through a slot within the surrounding axle tube to limit rotation of the second stage tube with the first stage shaft, and a crank arm and eccentric spindle are secured to the outer end portion of each second stage shaft for receiving a wheel. In modifications, the first stage shafts for both the left and right wheels are connected as one shaft, and a hydraulic winch cable and spool provide for pre-rotating the one shaft or the axle tube to lower and raise the vehicle. 
     Bekessy, U.S. Pat. No. 5,573,309 describes an in-line roller skate wheel and truck in which an elongated truck frame with a pair of spaced longitudinal side rails mount a plurality of roller wheels. At least one of the roller wheels has a hub core with a coaxial tire receiving shoulder. A tapered tire deflection controlling rim extends circumferentially about the shoulder, with rim side walls extending radially outward from a wide base at the tire receiving shoulder to a narrow peripheral surface. An annular resilient tire is mounted to the hub, engaging the tire receiving shoulder and encasing the tapered tire deflection controlling rim. The tire includes an annular ground engaging surface section and an annular high friction shoulder situated radially inward and axially outward of the ground engaging outer surface. The rim and tire configuration aid in maximizing speed and control in turns. Another one of the in-line roller wheels, situated at the heel end of the truck includes a tire of a slightly reduced diameter and is formed of a resilient material with a hardness value greater than the remaining tires on the truck. It also includes recessed braking dimples on its ground engaging surface to aid in approximating heels-forward “skid” stopping in a manner similar to stopping methods used by ice skaters. 
     Berges, FR2676397-A1 describes an integrated suspension wheel and shock absorber formed from a rigid rim which supports a tire. Four rings of cylindrical form join the rim to the hub. Paddle blades located radially between the suspension rings increase transmission of the torque. The rings serve progressively as shock absorbers. They are made of composite synthetic material having an elasticity calculated as a function of the required suspension. The material which fixes the rings to the rim and to the hub is a mono- or multi-component polyurethane. 
     Shepherd&#39;s Complete Specification, A.D. Dec. 21, 1896, No. 29,276. This reference was provided by the United States Patent and Trademark Office during prosecution of the parent case of this CIP. 
     The prior art teaches shock absorbers placed along a skate shoe, on a castor bracket, in a skate suspension housing, in a boot of a roller skate, in a hub cantilevered from an exterior support arm, and in other applications, as for instance, within a bicycle wheel hub. However, the prior art does not teach that the shock absorbing means may be fitted within the hub of the wheel with merely a single axle attached to a frame, to provide a highly compact and inexpensive shock system. The present invention fulfills these needs and provides further related advantages as described in the following summary. 
     SUMMARY OF THE INVENTION 
     The present invention teaches certain benefits in construction and use which give rise to the objectives described below. 
     The present invention provides a wheel having a tire mounted on a wheel rim and a central wheel hub adapted for low friction rotation through the use of bearings. A hub assembly within the wheel hub does not rotate. An arm is pivotally attached to the hub assembly and extends generally toward the center of the hub but is free to swing in an arc. The free end of the arm carries the axle to which the frame of a bicycle, skate, or the like, is mounted. A biasing device such as a spring, a pneumatic strut or an elastic body applies a force to the arm, urging the arm toward a rest position. As the wheel rotates under load, road shocks are transferred to the biasing device which acts as a shock absorber. A means for adjusting or fully canceling the effect of the biasing device is provided. 
     A primary objective of the present invention is to provide a wheel having advantages not taught by the prior art. 
     Another objective is to provide such a wheel having a shock absorbing capability built into the wheel hub. 
     A further objective is to provide such a wheel having a shock absorbing capability capable of supporting a static load as well as a dynamic load. 
     A still further objective is to provide such a wheel having a shock absorbing capability proportional to the degree of deflection of the wheel, i.e., increasing therewith. 
     A yet further objective is to provide such a wheel having a means for adjusting or fully canceling the effect of the shock absorbing capability. 
     A final objective is to provide such a wheel that fulfills these objectives in a construction that is competitive with, or exceeds the capabilities of the prior art, at a lower cost. 
     Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The accompanying drawings illustrate the present invention. In such drawings: 
     FIG. 1 is a partial cutaway perspective view of the preferred embodiment of the present invention; 
     FIG. 2A is an exploded view thereof; 
     FIG. 2B is a the assembled apparatus; 
     FIG. 3A is a side elevational view thereof in a relaxed position; 
     FIG. 3B is a side elevational view of an elastomeric part shown in the relaxed position corresponding with FIG. 3A; 
     FIG. 4A is a side elevational view thereof in a partially stressed position; 
     FIG. 4B is a side elevational view of the elastomeric part shown in a partially compressed state corresponding with FIG. 4A; 
     FIG. 5A is a side elevational view thereof in a fully stressed position; 
     FIG. 5B is a side elevational view of the elastomeric part shown in a fully compressed state corresponding with FIG. 5A; 
     FIG. 6 is a side elevational view partially broken away to show ribs for centering the elastomeric part. 
     FIGS. 7 &amp; 8 are side elevational views showing a fixture of the invention for pre-compressing the elastomeric part in relaxed and compressed states respectively. 
     FIGS. 9,  10  and  11  are full sectional views showing a fluid and bladder arrangement of the invention, with bladders full, half empty and mostly empty respectively.+ 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The above described drawing figures illustrate the invention, a self-suspended and shock absorbed wheel apparatus  10  comprising an outer wheel portion  20  adapted for rotation about a concentrically positioned, inner wheel portion  30  where the inner wheel portion  30  provides a pivotally engaged extension arm  40  supported by an elastomeric body  70 . The use of the word “arm” in this disclosure refers to either a single arm or multiple arms as either approach may be used to accomplish the objectives of the subject invention. The self-suspended wheel apparatus  10  may be configured for use with a roller skate, a bicycle or other devices. When used with a bicycle, the apparatus  10  may be mounted in a rear wheel in the bicycle frame, or in a front wheel mounted in a steering fork of the bicycle. 
     The outer wheel portion  20  is adapted, as will be described below, for rotation about the normally non-rotating, concentric, inner wheel portion  30 . The inner wheel portion  30  pivotally engages the extension arm  40  which terminates at a free end  42 . The extension arm  40 , in the preferred embodiment, is a pair of arms,  40 ′ and  40 ″ which act in unison. The free end  42  of the extension arm  40  engages a singular wheel mounting axle  60  adapted for receiving the wheel mounting frame at the axle&#39;s extremities  62 . A biasing means  70  engages the extension arm  40  and abuts a surface  32  of the inner wheel portion  30 . The biasing means  70  is enabled by its elastic nature and strength, for supporting the wheel mounting axle  60  which, in turn, supports part of the weight of the conveyance that is carried by the wheel, and for absorbing mechanical shocks to the wheel. It is of particular interest and novelty to realize that the self-suspending wheel apparatus  10  and the frame  50  to which it is mounted are joined together solely by the singular wheel mounting axle  60 . 
     In a preferred embodiment of the present invention, as shown in FIG. 1, the outer wheel portion  20  is represented by a hub housing as shown in the figures. The outer wheel portion  20  is joined to the inner wheel portion  30  by a pair of circular bearing assemblies  80  providing inner  82 , and outer  84 , bearing races as is well known in the art, and which enables the outer wheel portion  20  to rotate about the inner wheel portion  30 . Preferably, the biasing means  70  is an elastomeric body of a generally rectangular shape providing an axle access hole  72  at a first end  74  for operatively receiving the mounting axle  60 . One or more further holes or slots are positioned within and preferably through, the elastomeric body  70  and these are selected for providing an appropriate level of operable resilience as will be described below. 
     The inner wheel portion comprises a cylindrical shell  90  sandwiched between a pair of inner end rings  105 . The end rings  105  slide into engagement with the inner bearing race  82  from opposing sides of the hub housing  26 . A pair of outer end rings  100  also slide into the inner bearing race  82  from opposing outside directions and are fastened to each other and into place using common hardware in holes  102 . The end rings  100  hold the bearings  80  in place and insure that the assembly is secured into the hub  20 . Holes  104 , also in end rings  100 , each receive one pivot pin  106  as a press fit. Pins  106  extend laterally from holes  104  to engage holes  44  in extension arms  40 . Arms  40  are able to pivot freely about pins  106 . End caps  110  enclose the hub  20  from either side, and are fastened into place by common hardware using holes  112  and  46 . 
     A second end  78  of the elastomeric body  70  abuts an interior surface  32  of the cylindrical shell  90  such that the mounting axle  60  is free to compressively distort the elastomeric body  70 , as shown in FIGS. 4B,  5 B and  11 . Forces received from the ground surface upon which the wheel rides, are transferred through the bearings  80  to inside end rings  105  and shell  90  which, in turn transfer these forces to elastomeric body  70  and then to mounting axle  60  which supports the bicycle. Elastomeric body  70 , being of an elastic nature, tends to deform in compression which, due to the relative positions of the axle  60  and the elastomeric body  70 , causes the inner wheel portion  30  to rotate within hub  20 . A pair of bumber o-rings  65  are mounted on the axle  60 , as shown in FIG. 9-11 and provide elastic stop positioning of the axle at the ends of its excursion travel. 
     In an extension of the instant invention a means for partially and fully compressively distorting the elastomeric body  70  so as to disable the shock absorbing capability of the apparatus when desired, is provided. This is accomplished, preferably, through the use of a cable actuated means  158  for rotationally positioning the inner wheel portion  30  relative to the hub  20 . A cable  156 , which is preferably manually actuated is fastened to one of the end rings  100  as shown in FIG.  7 . and by shortening this cable, a spring is caused to exert a rotational force on the end ring  100 , thus compressing the elastomeric body  70  and reducing or eliminating its effect as an element in the suspension as shown in FIG.  8 . 
     In a further extension of the above described invention, one or more flexible bladders  120  is engaged within the elongate slot  76  of the elastomeric body  70 . The flexible bladder  120  receives a pressurized fluid  130  from, and exchanges the pressurized fluid  130  with, a fluid reservoir  140 , for maintaining the flexible bladders  120  in a fluid-full state. The bladders  120  and the fluid  130  provide a means for controlling the rate by which the elastic body  70  recuperates from distortion after it has been compressed as described above. This effect is based upon the fact that it takes time for the fluid  130  to move from the bladder  120  through a delivery tube  150 , for instance, to fluid reservoir  140 . Preferably, the apparatus further comprises a means for adjusting  160  of the fluid pressure within the pressurized fluid  130  so as to adjust the responsiveness and compliance of the suspension. Such an adjusting means  160  is preferably a simple manually adjustable screw mechanism  142  capable of positioning a piston  144  in a cylinder  146  of the reservoir  140  as shown in FIGS. 9-11. Thus, adjusting the screw mechanism  142  for positioning the piston  144  allows a selected volume of the reservoir  140  to be available for storing the fluid  130  and thus changes the total pressure in the system, including the bladders  120   120 , reservoir  140  and any delivery tube  150 . 
     While the invention has been described with reference to at least one preferred embodiment, it is to be clearly understood by those skilled in the art that the invention is not limited thereto. Rather, the scope of the invention is to be interpreted only in conjunction with the appended claims.