Patent Publication Number: US-4547173-A

Title: Toy vehicle claw wheel

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to toy vehicles and more particularly to a wheel and axle assembly for toy vehicles. 
     2. Background Art 
     Toy vehicles, in particular, motorized toy vehicles capable of four wheel, or even six wheel, drive such as those disclosed and claimed in prior U.S. Pat. Nos. 4,380,135; 4,467,557; and 4,459,776 that can clamber over various surfaces and obstacles are popular playthings. However, there remains a need for new toy vehicles that can overcome obstacles in an entertaining manner. In real life vehicles there have been attempts, particularly with respect to tractors, to increase traction of the vehicles by extendable lugs as in prior U.S. Pat. Nos. 1,326,500; 1,542,206; 1,578,478; 1,997,835; and 2,924,586. However, such prior art solutions to the problem of increasing traction, and hence the ability of the vehicle to overcome obstructions, are not applicable to toy vehicles. 
     SUMMARY OF THE INVENTION 
     The present invention is concerned with providing a wheel and axle assembly for a toy vehicle in which claws extend from the wheel upon the wheel otherwise being unable to overcome an obstruction. This and other objects and advantages of the invention are achieved by a wheel and axle assembly in which a hollow wheel with a peripheral wall is mounted for rotation on an axle and a spider with a leg spaced from the axle has a pivotally attached claw that is driven out, against a bias, through an opening in the peripheral wall of the wheel. Preferably, a four wheel drive toy vehicle is provided with two of each such wheels on each of two driven axles. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     For a better understanding of the present invention reference may be had to the accompanying drawing in which: 
     FIG. 1 is a perspective view of a toy vehicle embodying the present invention; 
     FIG. 2 is a perspective view of the vehicle shown in FIG. 1 with the claws extending out of the wheels; 
     FIG. 3 is an enlarged side elevational view of one of the wheel and axle assemblies with the outer shell of the wheel removed and the claws retracted; 
     FIG. 4 is a sectional view taken generally along the line 4--4 of FIG. 3; 
     FIG. 5 is a elevational view similar to that of FIG. 3 but with the claws extended; 
     FIG. 6 is an enlarged scale perspective view of one of the claws; 
     FIG. 7 is a schematic showing of the motor drive assembly; and 
     FIG. 8 is an elevational view similar to that of FIG. 5 but of an alternative embodiment. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawing in which like parts are designated by like reference numerals throughout the several views, there is shown in FIG. 1 a toy vehicle 10 having a chassis 12. Spaced apart axles 14 are carried by the chassis 12 for rotation relative to the chassis. A conventional battery motor, spring motor or inertia motor for toy vehicles may be drivingly connected by conventional means to one or both of the axles to rotate them in one direction, as shown, for example, in U.S. Pat. Nos. 3,359,680; 3,501,863; 3,540,152; 3,583,097; 3,810,515; 3,955,429; 3,959,920; and 3,981,098. 
     Each end of each axle 14 has a hollow wheel 16 mounted adjacent the end for rotation relative to the axle. Mating shell halves 17 and 18 form each wheel. An opening 20 in the side wall of each of the shell halves is aligned with another opening in the respective mating shell half. The openings 20 are sized to receive an axle 14 for rotation of the assembled hollow wheel 16 relative to the axle 14. Each pair of shells 17 and 18 fit together along a parting line 22 and together form a peripheral wall 24, the outside of which contacts the supporting surface for the toy vehicle. Formed along the outer surface of the peripheral wall 24 are alternating raised threads or lugs 26 and recessed spaces 28. Raised lugs 26 are generally parallel to the axle 14 and extend across the entire width of the outer surface of the peripheral wall 24. 
     Conveniently formed in substantially equidistant ones of the recessed spaces 28 are four openings 30 that also extend substantially across the entire width of the peripheral wall 24. As will become apparent to those skilled in the art there may be a greater or lesser number of the openings 30. However, it has been found that three or four openings are preferred. Similarly, the openings 30 need not extend across the entire width of the peripheral wall 24 but again such greater width has been found to provide a more dramatic effect. 
     Within each wheel 16, a spider 32 is secured to the axle 20 for rotation with the axle. As shown in FIG. 3, a setscrew 34 may be used to secure the center 35 of the spider 32 to the axle 14. Other alternative methods (not shown) such as a tight friction fit, a keyway or adhesives may also be used. Spider 32 has four legs 36 each extending, generally transverse to the axle 20, outwardly from the axle receiving center 35. Each of the legs 36 has an outer end 37. As illustrated in FIGS. 3 and 5 the legs 36 are generally tangent to the axle 20, however they could instead extend radially. 
     Attached to each of the legs 36 is a claw 40 that is made of a plastic material. One end 42 of the claw is provided with apertures 44 for attachment to a leg 36 by means of screws 46 or other fasteners. The other, free end 48 is formed with a series of serrations or teeth 50. Intermediate the end 42, adjacent which the claw will be attached to the leg, and the free end 48 is a section 52 of reduced material thickness that extends across the entire width of the claw 40 to provide an integral hinge which is sometimes referred to as a &#34;living hinge&#34;. Accordingly, each claw 40 is mounted on a respective leg 36 for pivotal movement relative to the leg about an axis parallel to the axis of the axle 20 to which the spider is secured. 
     Hinge section 52 also provides a bias resulting from the inherent resiliency of the plastic material. Thus, as the claw is illustrated in FIG. 6 with the one end 42 substantially transverse to the free end 48, there is a biasing force tending to urge the two ends into the same plane. Each claw 40 may pivot relative to the leg to which it is attached in either direction of rotation of the axle to which the spider is attached. However, the claws are oriented to pivot upon rotation of the axle in one direction so as to extend out a respective opening 30 and are biased by the &#34;living hinge&#34; in the opposite direction of rotation of the axle. 
     The free end 48 of each of the claws 40 attached to a respective one of the legs 36 engages wheel 16 at a respective one of the openings 30 as illustrated in FIGS. 3 and 4. Accordingly, rotation of the axle 20 is transmitted through engagement of the spider 32 and claws 40 subassembly with the wheel 16 to rotate the wheel across a relatively smooth supporting surface. However, when the wheels 16 or more particularly the outer surface of the peripheral wall 24 contacts a rough or obstructive surface such as 54 in FIG. 2, the engagement between the spider-claw subassembly and the wheel is overcome and the outer surface of the peripheral wall 24 slips. As the hollow wheel 16 begins to slip, the continued clockwise rotation of the axle 20 and the spider 32 causes each of the claws 40 to extend out through a respective opening 30 as illustrated in FIGS. 2 and 5. The extended claws 40 then contact the obstructions and enable the driven toy vehicle 10 to overcome the obstructions which caused the wheel 16 to slip or spin. After the rough surface has been overcome, claws 40 are retracted as a result of a bias from the &#34;living hinge&#34; 52. Extension of the claws 40 may be demonstrated by grasping an individual hollow wheel 16 and rotating the wheel counterclockwise as the axle remains stationary. 
     A motor and drive assembly that may be carried by the chassis 12 for the spaced apart axles 14 is schematically shown in FIG. 7. Extending out from each end of motor 60 is a output shaft 61 with a worm gear 62. Each of the axles 14 has a gear 64 secured to the axle for rotation with the axle and engaging worm gear 64. Thus, the motor simultaneously drives both of the axles 14. 
     In the illustrated embodiment, claw 40 is formed as a separate piece and attached to the respective leg 36 between the center portion 35 of the spider 32 and the outer end 37 of the leg. The portion of the leg 36 extending beyond the section to which the claw 40 is attached abuts claw 40 when the claw is extended and thus prevents each leg 36 and its attached claw 40 overriding, or going beyond, the respective opening 30. It may be desirable to form spider 32 with legs 36 and claws 40 as a single plastic piece. The section of reduced material thickness forming the &#34;living hinge&#34; could then be formed at the junction of the outer end 37 of the leg 36 and the one end 42 of the claw 40. In such a modification, stops, such as tabs or inward projections, (not shown) would have to be provided inside wheels 16 to prevent each leg and claw from rotating beyond the respective opening 30. 
     An alternative embodiment, illustrated in FIG. 8, has a wheel 70 provided with three openings 30 in the peripheral wall 71 rather than four as shown in FIGS. 3-5. Spider 72 is secured to the axle 14 by setscrew 34 through the center 75. Extending radially from the center are three radial legs 76, each of which has a free end 77. As with the embodiment shown in FIGS. 3-5, a claw 40 is attached to each of the legs 76 intermediate the center and the free end by screws 46 or other fasteners. The structure of the hollow wheel 70 is otherwise similar to that of the wheel 16. 
     While a particular embodiment of the present invention has been illustrated and described with some alternative modification, it will be apparent that further variation, changes and modifications will occur to those skilled in the art. It is intended in the appended claims to cover all such variations, changes and modifications as fall with the true spirit and scope of the present invention.