# US 4,393,953 A · Snowmobile

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- Number: US 4,393,953 A
- Document ID: US4393953A
- Status: Granted
- Kind: A
- Application number: 06/271,772
- Filed: 1981-06-08
- Granted: 1983-07-19
- Earliest claimed: 1981-06-08
- Inventors: Roland Boulianne
- Web page: https://patentgrep.com/patent/US4393953A

## CPC

- B62M 27/02: power driven
- B62M 2027/026: {Snow mobiles characterised by the suspension means}
- Y10S 280/90: Runner vehicle attachments
- B62M: RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR {SINGLE-TRACK} CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES (arrangements or mounting of transmissions in vehicles in general B60K; transmission elements per se F16)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A snowmobile of the type comprising a conventional front ski assembly and endless track but also a rear ski assembly and characterized by the latter, being pivotally connected relative to the body of the snowmobile and adjustable in height relative to the rear end of the endless track for improved longitudinal stability and comfort, better longitudinal load distribution and adjustment in relation with the condition of the snow on the ground and the desired traction. A suspension arm system resiliently and adjustably attaches the rear end of the endless track and the rear ski assembly to the body of the snowmobile with a remote control for selective adjustment of the height as aforementioned.

## Claims

### Claim 1

For a snowmobile including a body having a front end and a rear end, a front ski assembly attached to the body and carrying the front end thereof, an endless track attached to the body and carrying the rear end thereof, a rear ski and suspension assembly comprising a rear ski assembly and a suspension arm system pivotally attaching the rear ski assembly to the rear end of the body for vertical pivoting displacement of the rear ski assembly about a transverse pivot axis relative to the body, said suspension arm system including a pair of suspension arms longitudinally extending in fore-and-aft direction, and pivotally connecting the endless track and the rear ski assembly relative one to the other, and a resilient suspension pivotally connecting the suspension arms relative to the body for resilient up-and-down displacement of the suspension arms relative to the body.

### Claim 2 (depends on 1)

A rear ski and suspension assembly as defined in claim 1, wherein the suspension arm system includes an adjustment assembly connecting the resilient suspension relative to the suspension arms for selective pivotal adjustment of the latter and relative vertical adjustment of the endless track and rear ski assembly.

### Claim 3 (depends on 2)

A rear ski and suspension assembly as defined in claim 2, wherein the adjustment assembly includes a remote control mechanism constructed and arranged for remote pivotal adjustment of the suspension arms by the user in riding position on the snowmobile.

### Claim 4 (depends on 3)

A rear ski and suspension assembly for a snowmobile as defined in claim 3, wherein the endless track thereof includes a front end attached to the body and a rear end including a rear axle rotatably supported by the suspension arms and adjustable up-and-down upon pivotal adjustment of the suspension arms, the rear ski assembly includes a transverse axle and a pair of rear skis pivotally secured on the opposite area respectively of the transverse axle, and the pair of suspension arms are laterally spaced apart and rotatably carry the opposite ends respectively of the rear axle at one end and the transverse axle at the other end.

### Claim 5 (depends on 4)

A rear ski and suspension assembly as defined in claim 4, wherein the resilient suspension includes a first crank arm unit pivotally connecting to said body for rotation about one transverse axis, relative to the body, a second crank arm unit pivotally suspended from the first crank arm unit about another transverse axis, defining an articulation spaced from each one transverse axis, and pivotally carrying the suspension arms, and resilient means connected to the second crank arm unit and downwardly biasing the latter relative to said body toward resilient engagement of the rear end of the endless track and the rear ski assembly with the ground, and the adjustment assembly includes a link interconnecting said articulation and said transverse axle and adjustably defining the spacing between the same and a catch releasably holding said link in adjusted position.

### Claim 6 (depends on 5)

A rear ski and suspension assembly as defined in claim 5, wherein said link includes a rod connected at one end to said articulation, slidable endwise longitudinally relative to the snowmobile and to said transverse axle, said catch includes a clamp spring biased into operative clamping and holding engagement with the rod against endwise sliding thereof, and the remote control mechanism includes a cam device in operative engagement with the clamp, a push-pull cable connected to the cam device, and a hand control member connected to the push-pull cable and operatively actuating the same and releasing the clamp from clamping engagement with the rod, thereby allowing endwise adjustment of the latter.

### Claim 7 (depends on 1)

A rear ski and suspension assembly as defined in claim 1, wherein the resilient suspension includes a first crank arm unit pivotally connected to said body for rotation about one transverse axis relative to the body, a second crank arm unit pivotally suspended from the first crank arm unit about another transverse axis, defining an articulation spaced from said one transverse axis, and pivotally carrying the suspension arms, and resilient means connected to the second crank arm unit and downwardly biasing the latter relative to said body toward resilient engagement of the rear end of the endless track and the rear ski assembly with the ground.

### Claim 8 (depends on 1)

A rear ski and suspension assembly as defined in claim 1, wherein the resilient suspension includes a crank arm unit pivotally connected to said body for rotation about one transverse axis relative to the body, a pair of intermediate arms pivotally connected and suspended from the crank arm unit about another transverse axis, defining an articulation spaced from said one transverse axis, pivotally connected to the suspension arms respectively, and rotatively carrying the rear end of the endless track, and resilient shock absorbers connecting the rear ski assembly to the intermediate arms and downwardly biasing the latter relative to the body toward resilient engagement of the rear end of the endless track with the ground.

### Claim 9

A snowmobile comprising a body having a front end and a rear end, a front ski assembly attached to the body and carrying the front end thereof, an endless track attached to the body and carrying the rear end thereof, a rear ski assembly and a suspension arm system pivotally attaching the rear ski assembly and the endless track to the rear end of the body for vertical pivoting displacement of the rear ski assembly and the endless track about a transverse pivot axis relative to each other and to the body, said suspension arm system including a pair of suspension arms longitudinally extending in fore-and-aft direction, and pivotally connecting the endless track and the rear ski assembly relative one to the other, and a resilient suspension pivotally connecting the suspension arms relative to the body for resilient up-and-down displacement of the suspension arms relative to the body.