Wheel attaching device

An attaching mechanism for attaching an auxiliary wheel assembly to an axle-mounted wheel assembly includes a unitary annular disc with a plurality of apertures therein. The disc is fixed to the mounted wheel assembly for rotation therewith and includes a central opening which receives the axle. A hollow central screw member, which receives the axle, is fixed to the auxiliary wheel assembly by a plurality of struts. The struts support pivot members with ends receivable by the apertures in the attaching disc. A nut member is screwed onto the nut member and is engagable with the pivot members to pivot them into and out of interlocking engagement with the bores of the attaching disc.

BACKGROUND OF THE INVENTION 
This invention relates to a device for releasably attaching a pair of 
vehicle wheel assemblies together. 
A number of devices have been designed to releasably attach an auxiliary or 
outer wheel assembly to an axle-mounted, inner wheel assembly. With some 
of these devices, a plurality of bolts or levers must be sequentially 
tightened to form the attachment. In another type of attaching device, 
five cups are welded to the rim of the inner wheel assembly and five 
levers are pivotally attached to brackets fixed to the outer wheel 
assembly. A screw mechanism may then be screwed into a threaded bore to 
pivot the levers into engagement with the cups. However, this latter 
device is disadvantaged in that torque is transferred to the outer wheel 
assembly via the rim of the inner wheel assembly. Another disadvantage is 
that the outer wheel assembly may have to be rotated up to 36.degree. to 
align the levers and cups. Another disadvantage of this latter device is 
that it cannot be used when the inner wheel assembly is mounted on a long 
rack and pinion-type axle which extends a substantial distance outwardly 
beyond the inner wheel assembly and through the plane of the auxiliary 
wheel assembly. 
SUMMARY OF THE INVENTION 
An advantage of the present invention is that it provides a dual wheel 
attachment device through which torque may be transmitted between the axle 
and the outer wheel assembly without the torque being transmitted through 
the rim of the inner wheel assembly. 
A further advantage of this wheel attachment device is that it may be used 
to attach an outer wheel assembly to an inner wheel assembly where the 
axle extends through the plane of the outer wheel assembly. 
Another advantage of the present invention is that it prevents angular 
misalignment between the outer and inner wheel assemblies by more than an 
angle of approximately 5.6 degrees. 
Another advantage of the present invention is that it provides for coupling 
between wheel assemblies by manually rotating a single jackscrew nut 
member. 
These advantages are achieved, according to the present invention, in that 
it provides a device for quickly and releasably attaching an outer wheel 
assembly to an axle-mounted, inner wheel assembly. This attaching device 
includes an attaching disc with a plurality of radially extending tapered 
bores. The disc is bolted to the cast wheel of the inner wheel assembly in 
spaced-apart relationship to the rim of the inner wheel assembly. A 
plurality of support brackets are welded to the rim of the outer wheel 
assembly and include inner ends fixed to a hollow outside threaded 
jackscrew member through which extends the axle. A bellcrank is pivotally 
attached to each of the support brackets. A jackscrew nut member may then 
be rotated on the hollow jackscrew member to pivot the bellcranks so that 
their end portions are received in interlocking fashion by the tapered 
bores in the attaching disc.

DETAILED DESCRIPTION 
An attaching mechanism 10 couples an outer or auxiliary wheel assembly 12 
to an inner axle-mounted wheel assembly 14. The inner wheel assembly 14 
includes a cast wheel 16 with a central hub portion 17 fixed for rotation 
with a conventional rack and pinion-type axle 18 via a conventional split 
cone-type connector 20. A rim 22 supports a tire 24 in the conventional 
manner. The rim 22 is connected to the wheel 16 via sixteen lugs 26 (one 
of which is shown in FIG. 2) which are bolted to the wheel 16 via bolts 28 
(one of which is shown in FIG. 2). The outer wheel assembly 12 includes a 
conventional rim 30 which supports a tire 32. 
The attaching mechanism 10 includes a one-piece or unitary and generally 
annular-shaped member or attaching disc 40. Disc 40 includes a central 
opening 42 which receives a hub portion 17 of the wheel 16 and through 
which extends the axle 18. The disc 40 includes a radially extending 
portion 44, thirty-two rounded axially extending segments 46 and 
thirty-two axially and radially extending rib portions 48 which 
interconnect portions 44 and 46. The portion 44 includes sixteen regularly 
spaced axial bores 50 extending therethrough for receiving the bolts 28 so 
that the attaching disc 40 may be fixed to the wheel 16 in coaxial 
relationship to the axle 18 and in spaced-apart, non-engaging relationship 
to the rim 22 (as best seen in FIG. 2). Each segment 46 includes a tapered 
bore 52 extending radially therethrough. Each tapered bore 52 tapers 
radially outwardly from a larger diameter end to a smaller diameter end. 
The attaching mechanism 10 also includes a support structure fixed for 
rotation with the outer wheel assembly 12. The support structure includes 
a central hollow outside threaded jackscrew member 60. Member 60 has an 
inside diameter large enough so that it may coaxially receive the axle 18 
in spaced-apart relationship thereto. Five pairs of spaced-apart struts 62 
are fixed to an inboard end of the member 60. The pairs of struts 62 
extend radially and partially towards the inner wheel assembly 14 to their 
outer ends. The outer ends of struts 62 are fixed to the inboard ends of 
substantially axially extending parallel spaced-apart struts 64. The 
outboard ends of struts 64 are welded or fixed to the rim 30 of the outer 
or auxiliary wheel assembly 12. A brace 66 interconnects each pair of 
struts 64 for added rigidity. 
A pivot or bellcrank member 70 is pivotally supported between each pair of 
struts 62 and 64 via a pivot pin 72 which extends through bores in the 
interconnected end portions of struts 62 and 64. Each pivot member 70 
includes a pivot portion with bore 74 for rotatably receiving the pivot 
pin 72. A first arm 76 extends from the pivot portion and includes a 
frustoconical end portion 78 for being matingly received by one of the 
tapered bores 52. A second arm 80 extends substantially radially inwardly 
and terminates in a bifurcated end portion 82. Each arm 80 also includes a 
pair of raised shoulder portions 84 which cooperate with the struts 62 to 
limit lateral movement of the pivot members 70 relative to the struts 62. 
The attaching mechanism 10 also includes a coupling or jackscrew nut member 
90 threaded on the central jackscrew member 60. The jackscrew nut member 
90 includes a hollow cylindrical portion 92. A pair of torque arms 94 
extends from the outboard end of cylindrical portion 92. A flange 96 
extends radially from the inboard end of cylindrical portion 92 and is 
received by the bifurcated end portion 82 of pivot member 70. The 
cylindrical portion 92 also coaxially receives the axle 18, since it is 
coaxially mounted on the member 60. 
MODE OF OPERATION 
To attach the outer or auxiliary wheel assembly 12 with the connecting 
mechanism 10 to the inner or axle-mounted wheel assembly 14, the nut 
member 90 is rotated on the screw member 60 toward the outboard end 
thereof to pivot the pivot members 70 so that their frustoconical ends 78 
are pivoted radially inwardly to clear flange portion 46 of attaching disc 
40. Wheel assembly 12 is then coaxially positioned on the axle 18 and 
moved inboard towards the inner wheel assembly 14 until the frustoconical 
ends 78 of pivots 70 are aligned with the tapered bores 52. Since the 32 
tapered bores are evenly angularly spaced apart by no more than 11.25 
degrees, the wheel assembly 12 will not have to be rotated by more than 
half this amount, or 5.625 degrees, to align the ends 78 with the tapered 
bores 52. 
The vehicle operator then rotates nut member 90 towards the inboard end of 
screw member 60 to pivot the pivot members 70 until their frustoconical 
ends 72 are securely engaged with the walls of the tapered bores 52. In 
this position, the connecting mechanism 10 holds the central jackscrew 
member 60 in coaxially spaced-apart relationship to the axle 18. 
When torque is applied to the axle 18 from the vehicle transmission (not 
shown) this torque is transmitted to the rim 30 of the outer wheel 
assembly 12 via the cast wheel 16, the bolts 28, attaching disc 40, pivots 
70 and struts 62 and 64. Thus, the torque transmitted between the axle 18 
and the outer wheel assembly 12 is not transmitted via the rim 22 of the 
inner wheel assembly 14. This prevents undue torque loads from damaging 
the rim 22 of the inner wheel assembly 14. 
To remove the outer wheel assembly 12 from the inner wheel assembly, the 
jackscrew nut 90 is rotated on the jackscrew member 60 back towards its 
outboard end to pivot the pivots 70 to withdraw their ends 78 from the 
bores 52. The outer wheel assembly 12 may then be pulled axially away from 
the inner wheel assembly 14 and removed from the axle 18.