CA1227823A - Snowmobile torsion bar suspension - Google Patents
Snowmobile torsion bar suspensionInfo
- Publication number
- CA1227823A CA1227823A CA000473450A CA473450A CA1227823A CA 1227823 A CA1227823 A CA 1227823A CA 000473450 A CA000473450 A CA 000473450A CA 473450 A CA473450 A CA 473450A CA 1227823 A CA1227823 A CA 1227823A
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- CA
- Canada
- Prior art keywords
- torsion bar
- chassis
- ski
- mounting
- bar
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
ABSTRACT
A torsion bar suspension system for the front skis of a snowmobile. The suspension includes a mounting apparatus for independently mounting each ski to the snowmobile chassis, this apparatus being fixed against rotation but being allowed generally vertical movement in response to uneven terrain. Each ski is allowed to rotate with respect to the mounting appara-tus, permitting operation of conventional steering mechanisms. A torsion bar connects the two mounting apparatuses to stabilize the snowmobile. The torsion bar is connected to each mounting apparatus through a sliding insert carried by the apparatus, the insert absorbing and permitting relative longitudinal move-ment of the torsion bar with respect to the mounting apparatus. The torsion bar, which has a plurality of obtuse bends, is mounted to the snowmobile chassis by a pair of bushings. Each bushing has a generally con-vex inner surface for facilitating passage of the bushing around the bends of the torsion bar during assembly.
A torsion bar suspension system for the front skis of a snowmobile. The suspension includes a mounting apparatus for independently mounting each ski to the snowmobile chassis, this apparatus being fixed against rotation but being allowed generally vertical movement in response to uneven terrain. Each ski is allowed to rotate with respect to the mounting appara-tus, permitting operation of conventional steering mechanisms. A torsion bar connects the two mounting apparatuses to stabilize the snowmobile. The torsion bar is connected to each mounting apparatus through a sliding insert carried by the apparatus, the insert absorbing and permitting relative longitudinal move-ment of the torsion bar with respect to the mounting apparatus. The torsion bar, which has a plurality of obtuse bends, is mounted to the snowmobile chassis by a pair of bushings. Each bushing has a generally con-vex inner surface for facilitating passage of the bushing around the bends of the torsion bar during assembly.
Description
2~7~
SNOWMOBILE TORSION JAR SUSPENSION
TECHNICAL F I E Lo The invention relates to a torsion bar suspend soon system for snowmobiles.
BACKGROUND ART
The front suspension of snowmobiles, i.e., the suspension for the two front skis, characteristically has been comprised of leaf springs attached from a steering column to the upper surface of each ski.
Commonly the skis are allowed to pitch about a trays-lo verse axis according to the terrain encountered, and the pitch of each ski is commonly dampened by a device such as a shock absorber.
Attempts have been made to stabilize snowmo-bites with such suspensions utilizing a torsion bar, but such attempts have been frustrated by the fact that the skis are the steering mechanism of a snowmo-bile and must therefore be allowed to turn freely from side to side. US. Patent 3,674,103, Kiekhaefer, de-plats one such snowmobile utilizing a torsion bar to stabilize a suspension as described above. The bar engages a slot, formed adjacent the top surface of each ski by a strap of iron, at the point where the steering axis intersects the ski, thereby preventing the bar from being withdrawn from the slot when the ski is turned.
,'Z27~23 This system has serious drawbacks, however, in that the fit between tune torsion bar and the slot must necessarily be loose enough to allow the ski to be turned through substantial angles. The loose fit pro-motes deformation and misalignment of the parts under rough terrain conditions, particularly since the parts are close to the ground and unprotected from debris which may be encountered on the trail. Also, the slot area may easily become clogged with ice or snow, in-lo habiting proper steering.
More recently, alternate torsion bar system shave been developed which avoid the above-mentioned problems but involve considerable complexity of menu-lecture, assembly, and/or maintenance.
DISCLOSURE OF INVENTION
The present invention provides a torsion bar suspension for the two front skis of a snowmobile.
The suspension includes means for independently mount-in each ski to the snowmobile chassis so that each ski independently and resiliently recoils vertically in response to uneven terrain, the mounting means be-in fixed against rotation but permitting rotation of the skis to facilitate steering. Torsion bar means is provided for elastically biasing the mounting means of each ski vertically in response to vertical movement of the mounting means of the other ski, and a sliding insert is carried by the mounting means for engaging the torsion bar means, permitting limited relative longitudinal movement of the torsion bar means with respect to the mounting means.
In a preferred embodiment, the mounting means includes, for each ski, a mounting column extending generally vertically from the ski, a pair of trays-verse parallel pivot bars, each pivotal attached at `` ~Z~7~23 one end to the chassis and at the other end to the mounting column, the pivot bars allowing generally vertical movement of the column, and a trailing arm extending rearwardly from the mounting column and pi-ovally attached a its rearward end to the chassis, the trailing arm allowing generally vertical movement of the column and having a longitudinal channel for closely receiving the sliding insert.
Preferably the torsion bar means is a contain-o use rod of circular cross-section having a plurality of bends so that it includes a central portion extend-in laterally across the chassis, a lever portion ox-tending laterally and forwardly from each end of the central portion, and a sliding insert engaging portion extending laterally to be received by a lateral hole in the sliding insert. The suspension system prefer-ably includes one or more bushings carried by the chassis for closely engaging the torsion bar, each bushing having a rounded bar engaging surface to allow the bushing to so de past the bends in the bar during assembly. Preferably the radius of the rounded bar engaging surface is equal to or less than the radius of the bends in the torsion bar.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a broken-away partial perspective view of a snowmobile chassis fitted with a torsion bar suspension of the invention, Figure is a broken side elevation Al view of Figure l;
Figure 3 is a cross-sectional view of Figure 2 taken along line 3-3 thereof;
Figure 4 is a perspective view of a sliding insert;
Figure 5 is a broken-away view of a torsion bar passing through a bushing of the invention;
Figure 6 is a grog -sectional broken-away view of Figure 5;
Figure 7 is a partial cross-sectional broken-away View of a bushing sliding past a bend in a torsion bar;
Figure 8 is a cross-sectional view of a bushing of the invention;
- Figure 9 is a cross-sectional view of another bushing of the invention; and lo Figure ill is a cross-sectional broken-away vie of another bushing of the invention.
BEST MODE FOR CARRYING OVA THE INVENTION
_ Referring to Figure 1, a snowmobile chassis (10) is provided with two front skis (11), each ski being independently mounted to the chassis (10). The mounting means allows each ski to independently and resiliently recoil generally vertically in response to uneven terrain. Although the mounting means may be of any of a variety of types, the skis must be rotatable with respect to the mounting means to allow the snow-mobile to be steered properly. Figure 1 depicts a preferred mounting means in which a steering post (12) is attached to the ski (11) and passes upwardly within a mounting post l21 ) . The steering post 112) is rotatable with respect to the column (21) and is at-lacked above the column (21) to a steering mechanism by well-known mechanical linkages which are not shown in Figure 1 for purposes of clarity.
A pair of transverse parallel pivot bars (23) are attached from the mounting column (21) to the chassis (10). The pivot bars (23) pivot at each end, allowing the mounting column (21) to freely move gent orally vertically. A trailing arm (22) is rigidly attached to the mounting column (21) and is pivotal attached at its rearward end to the chassis (10) by a ;27~'3 pivot bolt ~25). the trailing arm ~22~ therefore also permits generally vertical movement of the mounting column (21). A suspension spring is also provided, the preferred embodiment of Figure 1 depicting a coil spring (13) attached between the mounting column (21) and the chassis (10). The spring desirably also is provided with a dampening means, which may be a shock absorber (14) or similar device mounted coccal with the coil spring (13).
lo A suspension SEIKO as has been described is stabilized by providing a torsion bar (20) to transmit vertical forces acting upon either ski (11) and its respective mounting means to the other ski (11) by way of its mounting means. Such a torsion bar (20) goner-ally includes a central portion (17) extending later-ally across the snowmobile chassis (10), a lever port lion (18) extending generally forwardly, and a mounting means engaging portion (19) extending later-ally.
The function of a torsion bar such as (20) is to elastically transmit vertical forces acting upon one ski (11) to the other ski (11) to stabilize the snowmobile against rolling by jell known principles.
According to the described function of the ion-soon bar (20), it is inherent in its structure that the engaging portion (19) move along an arc coaxial with the axis of the central portion (17) of the ion-soon bar (20). us the engaging portion (19) moves along this arc, the vertical component of this motion 0 corresponds to the vertical movement of the ski (11) and the mounting means. The horizontal component of this movement, however, must be mechanically absorbed because the ski (11) and its mounting means is not permitted such horizontal movement.
The invention provides a sliding insert (24) closely received within a channel in the trailing arm it ;2;2~7~;~3 ~22). The insert is proviaecl with a lateral hole ~27) for closely receiving the engaging portion (19) of the torsion bar (20). The engaging portion (19) is per-milted both rotational and transverse movement with respect to the insert (24), but the insert (24) and the enraging portion (19) fit snugly to prevent any significant longitudinal movement there between. Aver-lures (26) are provided in the trailing arm (22) to reveal the hole (27) of the insert (24) when the in-sort (24) is in the channel of the trailing arm (22), allowing the engaging portion (19) of the torsion bar (20) to pass through the insert (24). See Figure 2.
As a ski (11) encounters a bump in the trail, the ski (11) will deflect upwardly thereby causing the mounting means to likewise move upwardly. The torsion bar (20) will twist, its engaging portion (19) moving along an arc, the vertical component of which core-spends to the vertical movement of the mounting means, and the horizontal component of which is taken up by the sliding insert (24). The upward reflection is thereby transmitted to the other ski (11) to stabilize the snowmobile.
It should be noted that, for the mounting means depicted in Figure 1, the sliding insert must also allow for lateral movement of the insert ~24) with respect to the torsion bar (20). Referring to Figure 1, as the mounting column (21~ moves vertically in response to terrain variations it will also move slightly laterally as it travels along an arc having a radius defined by the parallel pivot bars (23).
Similarly, the insert also compensates for the longitudinal movement of the trailing arm (22) with respect to the torsion bar (20) due to the fact that the trailing arm is also moving along an arc having its axis as the pivot bolt (25).
It will now be understood that the insert (24) compensates for and absorb movement of the parts in three directions: the longitudinal movement of the torsion bar (20) due to its movement along an art the longitudinal movement of the trailing arm (22) due to its movement along an arc, and the lateral movement of the trailing arm (22) due to its movement along the arc defined by the pivot bars (23).
The insert (24) thus provides a very simple o solution to what has heretofore been a relatively come placated mechanical problem. The insert (24) sub Stan-tidally eliminates all play between the respective parts, significantly reducing wear, and reducing or eliminating the danger of permanent deformation of the parts under even severe and sudden stresses, as may be encountered on rough trails.
The mechanical linkage is also economically manufactured. The insert (24) is preferably molded from any of a variety of low friction, high density plastics. Figure 4 depicts a preferred configuration for the insert (24), although it will be understood that any of a variety of configurations which effect lively engage the torsion bar (20) and ride longitude-natty along the trailing arm ~22) would suffice.
Referring to figures I the invention also provides a unique bushing (30) for mounting the ion-soon bar l20) to the chassis (10). As the torsion bar is preferably a single, continuous, generally Solon-Dracula rod, it is particularly suited to be mounted to the chassis (10) by a collar-shaped bushing. In order to assemble the parts, however, it is necessary to slide the bushing vast bends in the torsion bar (20).
If the interior bushing surface (31) which engages the torsion bar (20) is generally cylindrical, it will pass these bends only with difficulty, if at all. The invention therefore provides a bushing (30) having a generally towardly collar (32), the interior surface (31) of which is curved convexly. If the radius of the curve is equal to or less than the radius of the bends in the torsion bar (20), the bushing (30) will slide past these bends without difficulty, and yet snugly engage the torsion bar (20) when assembled.
Figures 5-10 show a variety of configurations for such a bushing (30). In Figure 6 the bushing (30) is comprised of two pieces, a collar (32) and a no-lo twining shell (34). Figure 7 depicts a bushing (MU) molded integrally from any of a variety of durable plastics. Figures 8 and show alternate curvatures for the interior engaging surface (31). In figure 8 the surface (31) is generally funnel-shaped rather than semi-circular; in Figure 9 the curvature is pros-en only for a portion of the circumference of the bushing (30).
Figure 10 shows a particularly preferred con-figuration in which the bushing (30) is partially no-cussed into the chassis (10) for added strength. The interior surface (31) is comprised of a plurality of generally flat surfaces which approximate the required curvature. Such a configuration is easier to manufac-lure than a perfectly curved surface.
As depicted in Figures 5, 6, and 10, preferably the bushing includes a disc-shaped flange (33) for mounting the bushing to the chassis (10). This may be accomplished by using any of a variety of well-known fasteners; preferably, rivets are employed.
It will now be understood that by practicing the invention a torsion bar suspension for a snowmo-bile may be cheaply and easily manufactured and as-symboled. The system requires comparatively few parts, and the parts provide a simple assembly which company sates for divergent movement of the parts while elm-inating unnecessary play to avoid the danger of I
deformation of the parts under severe and sudden stresses.
While a preferred embodiment of the present invention has been described, it should be understood that various changes, adaptations and modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims.
SNOWMOBILE TORSION JAR SUSPENSION
TECHNICAL F I E Lo The invention relates to a torsion bar suspend soon system for snowmobiles.
BACKGROUND ART
The front suspension of snowmobiles, i.e., the suspension for the two front skis, characteristically has been comprised of leaf springs attached from a steering column to the upper surface of each ski.
Commonly the skis are allowed to pitch about a trays-lo verse axis according to the terrain encountered, and the pitch of each ski is commonly dampened by a device such as a shock absorber.
Attempts have been made to stabilize snowmo-bites with such suspensions utilizing a torsion bar, but such attempts have been frustrated by the fact that the skis are the steering mechanism of a snowmo-bile and must therefore be allowed to turn freely from side to side. US. Patent 3,674,103, Kiekhaefer, de-plats one such snowmobile utilizing a torsion bar to stabilize a suspension as described above. The bar engages a slot, formed adjacent the top surface of each ski by a strap of iron, at the point where the steering axis intersects the ski, thereby preventing the bar from being withdrawn from the slot when the ski is turned.
,'Z27~23 This system has serious drawbacks, however, in that the fit between tune torsion bar and the slot must necessarily be loose enough to allow the ski to be turned through substantial angles. The loose fit pro-motes deformation and misalignment of the parts under rough terrain conditions, particularly since the parts are close to the ground and unprotected from debris which may be encountered on the trail. Also, the slot area may easily become clogged with ice or snow, in-lo habiting proper steering.
More recently, alternate torsion bar system shave been developed which avoid the above-mentioned problems but involve considerable complexity of menu-lecture, assembly, and/or maintenance.
DISCLOSURE OF INVENTION
The present invention provides a torsion bar suspension for the two front skis of a snowmobile.
The suspension includes means for independently mount-in each ski to the snowmobile chassis so that each ski independently and resiliently recoils vertically in response to uneven terrain, the mounting means be-in fixed against rotation but permitting rotation of the skis to facilitate steering. Torsion bar means is provided for elastically biasing the mounting means of each ski vertically in response to vertical movement of the mounting means of the other ski, and a sliding insert is carried by the mounting means for engaging the torsion bar means, permitting limited relative longitudinal movement of the torsion bar means with respect to the mounting means.
In a preferred embodiment, the mounting means includes, for each ski, a mounting column extending generally vertically from the ski, a pair of trays-verse parallel pivot bars, each pivotal attached at `` ~Z~7~23 one end to the chassis and at the other end to the mounting column, the pivot bars allowing generally vertical movement of the column, and a trailing arm extending rearwardly from the mounting column and pi-ovally attached a its rearward end to the chassis, the trailing arm allowing generally vertical movement of the column and having a longitudinal channel for closely receiving the sliding insert.
Preferably the torsion bar means is a contain-o use rod of circular cross-section having a plurality of bends so that it includes a central portion extend-in laterally across the chassis, a lever portion ox-tending laterally and forwardly from each end of the central portion, and a sliding insert engaging portion extending laterally to be received by a lateral hole in the sliding insert. The suspension system prefer-ably includes one or more bushings carried by the chassis for closely engaging the torsion bar, each bushing having a rounded bar engaging surface to allow the bushing to so de past the bends in the bar during assembly. Preferably the radius of the rounded bar engaging surface is equal to or less than the radius of the bends in the torsion bar.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a broken-away partial perspective view of a snowmobile chassis fitted with a torsion bar suspension of the invention, Figure is a broken side elevation Al view of Figure l;
Figure 3 is a cross-sectional view of Figure 2 taken along line 3-3 thereof;
Figure 4 is a perspective view of a sliding insert;
Figure 5 is a broken-away view of a torsion bar passing through a bushing of the invention;
Figure 6 is a grog -sectional broken-away view of Figure 5;
Figure 7 is a partial cross-sectional broken-away View of a bushing sliding past a bend in a torsion bar;
Figure 8 is a cross-sectional view of a bushing of the invention;
- Figure 9 is a cross-sectional view of another bushing of the invention; and lo Figure ill is a cross-sectional broken-away vie of another bushing of the invention.
BEST MODE FOR CARRYING OVA THE INVENTION
_ Referring to Figure 1, a snowmobile chassis (10) is provided with two front skis (11), each ski being independently mounted to the chassis (10). The mounting means allows each ski to independently and resiliently recoil generally vertically in response to uneven terrain. Although the mounting means may be of any of a variety of types, the skis must be rotatable with respect to the mounting means to allow the snow-mobile to be steered properly. Figure 1 depicts a preferred mounting means in which a steering post (12) is attached to the ski (11) and passes upwardly within a mounting post l21 ) . The steering post 112) is rotatable with respect to the column (21) and is at-lacked above the column (21) to a steering mechanism by well-known mechanical linkages which are not shown in Figure 1 for purposes of clarity.
A pair of transverse parallel pivot bars (23) are attached from the mounting column (21) to the chassis (10). The pivot bars (23) pivot at each end, allowing the mounting column (21) to freely move gent orally vertically. A trailing arm (22) is rigidly attached to the mounting column (21) and is pivotal attached at its rearward end to the chassis (10) by a ;27~'3 pivot bolt ~25). the trailing arm ~22~ therefore also permits generally vertical movement of the mounting column (21). A suspension spring is also provided, the preferred embodiment of Figure 1 depicting a coil spring (13) attached between the mounting column (21) and the chassis (10). The spring desirably also is provided with a dampening means, which may be a shock absorber (14) or similar device mounted coccal with the coil spring (13).
lo A suspension SEIKO as has been described is stabilized by providing a torsion bar (20) to transmit vertical forces acting upon either ski (11) and its respective mounting means to the other ski (11) by way of its mounting means. Such a torsion bar (20) goner-ally includes a central portion (17) extending later-ally across the snowmobile chassis (10), a lever port lion (18) extending generally forwardly, and a mounting means engaging portion (19) extending later-ally.
The function of a torsion bar such as (20) is to elastically transmit vertical forces acting upon one ski (11) to the other ski (11) to stabilize the snowmobile against rolling by jell known principles.
According to the described function of the ion-soon bar (20), it is inherent in its structure that the engaging portion (19) move along an arc coaxial with the axis of the central portion (17) of the ion-soon bar (20). us the engaging portion (19) moves along this arc, the vertical component of this motion 0 corresponds to the vertical movement of the ski (11) and the mounting means. The horizontal component of this movement, however, must be mechanically absorbed because the ski (11) and its mounting means is not permitted such horizontal movement.
The invention provides a sliding insert (24) closely received within a channel in the trailing arm it ;2;2~7~;~3 ~22). The insert is proviaecl with a lateral hole ~27) for closely receiving the engaging portion (19) of the torsion bar (20). The engaging portion (19) is per-milted both rotational and transverse movement with respect to the insert (24), but the insert (24) and the enraging portion (19) fit snugly to prevent any significant longitudinal movement there between. Aver-lures (26) are provided in the trailing arm (22) to reveal the hole (27) of the insert (24) when the in-sort (24) is in the channel of the trailing arm (22), allowing the engaging portion (19) of the torsion bar (20) to pass through the insert (24). See Figure 2.
As a ski (11) encounters a bump in the trail, the ski (11) will deflect upwardly thereby causing the mounting means to likewise move upwardly. The torsion bar (20) will twist, its engaging portion (19) moving along an arc, the vertical component of which core-spends to the vertical movement of the mounting means, and the horizontal component of which is taken up by the sliding insert (24). The upward reflection is thereby transmitted to the other ski (11) to stabilize the snowmobile.
It should be noted that, for the mounting means depicted in Figure 1, the sliding insert must also allow for lateral movement of the insert ~24) with respect to the torsion bar (20). Referring to Figure 1, as the mounting column (21~ moves vertically in response to terrain variations it will also move slightly laterally as it travels along an arc having a radius defined by the parallel pivot bars (23).
Similarly, the insert also compensates for the longitudinal movement of the trailing arm (22) with respect to the torsion bar (20) due to the fact that the trailing arm is also moving along an arc having its axis as the pivot bolt (25).
It will now be understood that the insert (24) compensates for and absorb movement of the parts in three directions: the longitudinal movement of the torsion bar (20) due to its movement along an art the longitudinal movement of the trailing arm (22) due to its movement along an arc, and the lateral movement of the trailing arm (22) due to its movement along the arc defined by the pivot bars (23).
The insert (24) thus provides a very simple o solution to what has heretofore been a relatively come placated mechanical problem. The insert (24) sub Stan-tidally eliminates all play between the respective parts, significantly reducing wear, and reducing or eliminating the danger of permanent deformation of the parts under even severe and sudden stresses, as may be encountered on rough trails.
The mechanical linkage is also economically manufactured. The insert (24) is preferably molded from any of a variety of low friction, high density plastics. Figure 4 depicts a preferred configuration for the insert (24), although it will be understood that any of a variety of configurations which effect lively engage the torsion bar (20) and ride longitude-natty along the trailing arm ~22) would suffice.
Referring to figures I the invention also provides a unique bushing (30) for mounting the ion-soon bar l20) to the chassis (10). As the torsion bar is preferably a single, continuous, generally Solon-Dracula rod, it is particularly suited to be mounted to the chassis (10) by a collar-shaped bushing. In order to assemble the parts, however, it is necessary to slide the bushing vast bends in the torsion bar (20).
If the interior bushing surface (31) which engages the torsion bar (20) is generally cylindrical, it will pass these bends only with difficulty, if at all. The invention therefore provides a bushing (30) having a generally towardly collar (32), the interior surface (31) of which is curved convexly. If the radius of the curve is equal to or less than the radius of the bends in the torsion bar (20), the bushing (30) will slide past these bends without difficulty, and yet snugly engage the torsion bar (20) when assembled.
Figures 5-10 show a variety of configurations for such a bushing (30). In Figure 6 the bushing (30) is comprised of two pieces, a collar (32) and a no-lo twining shell (34). Figure 7 depicts a bushing (MU) molded integrally from any of a variety of durable plastics. Figures 8 and show alternate curvatures for the interior engaging surface (31). In figure 8 the surface (31) is generally funnel-shaped rather than semi-circular; in Figure 9 the curvature is pros-en only for a portion of the circumference of the bushing (30).
Figure 10 shows a particularly preferred con-figuration in which the bushing (30) is partially no-cussed into the chassis (10) for added strength. The interior surface (31) is comprised of a plurality of generally flat surfaces which approximate the required curvature. Such a configuration is easier to manufac-lure than a perfectly curved surface.
As depicted in Figures 5, 6, and 10, preferably the bushing includes a disc-shaped flange (33) for mounting the bushing to the chassis (10). This may be accomplished by using any of a variety of well-known fasteners; preferably, rivets are employed.
It will now be understood that by practicing the invention a torsion bar suspension for a snowmo-bile may be cheaply and easily manufactured and as-symboled. The system requires comparatively few parts, and the parts provide a simple assembly which company sates for divergent movement of the parts while elm-inating unnecessary play to avoid the danger of I
deformation of the parts under severe and sudden stresses.
While a preferred embodiment of the present invention has been described, it should be understood that various changes, adaptations and modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims.
Claims (11)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A torsion bar suspension for a snowmobile of the type having a chassis and two front skis com-prising:
means for independently and rotatably mounting each ski to the chassis so that each ski independently and resiliently recoils ver-tically in response to uneven terrain, the skis being rotatable with respect to the mounting means for steering the snowmobile;
torsion bar means for elastically biasing the mounting means of one ski vertically in response to vertical movement of the mounting means of the other ski; and a sliding insert carried by the mounting means for engaging the torsion bar means, said insert being permitted limited relative longi-tudinal movement with respect to the mounting means and thereby permitting similar longitu-dinal movement of the torsion bar means.
means for independently and rotatably mounting each ski to the chassis so that each ski independently and resiliently recoils ver-tically in response to uneven terrain, the skis being rotatable with respect to the mounting means for steering the snowmobile;
torsion bar means for elastically biasing the mounting means of one ski vertically in response to vertical movement of the mounting means of the other ski; and a sliding insert carried by the mounting means for engaging the torsion bar means, said insert being permitted limited relative longi-tudinal movement with respect to the mounting means and thereby permitting similar longitu-dinal movement of the torsion bar means.
2. The suspension of Claim 1 wherein the mounting means includes, for each ski, a mounting col-umn extending generally vertically from the ski, and a trailing arm extending rearwardly from the mounting column and pivotally attached at its rearward end to the chassis, the trailing arm allowing generally ver-tical movement of the column and having a longitudinal channel for closely receiving the sliding insert.
3. The suspension of Claim 2 wherein the mounting means further includes a pair of transverse parallel pivot bars, each pivotally attached at one end to the chassis and at the other end to the mount-ing column, the pivot bars allowing generally vertical movement of the column with respect to the chassis.
4. The suspension of Claim 1 wherein the tor-sion bar means includes a bar having:
a central portion extending laterally across the chassis a lever portion extending laterally and forwardly from each end of the central portion and forming an obtuse angle therewith; and a sliding insert engaging portion extend-ing from the outward end of each lever portion, the axes of the engaging portions being ori-ented generally parallel to the axis of the central portion.
a central portion extending laterally across the chassis a lever portion extending laterally and forwardly from each end of the central portion and forming an obtuse angle therewith; and a sliding insert engaging portion extend-ing from the outward end of each lever portion, the axes of the engaging portions being ori-ented generally parallel to the axis of the central portion.
5. The suspension of Claim 4 wherein the sliding insert has a lateral hole for closely receiv-ing the engaging portion of the torsion bar, the hole allowing rotation and lateral translation of the bar with respect to the insert.
6. The suspension of Claim 1 wherein the tor-sion bar means includes a single continuous torsion bar having a substantially consistent circular cross section and a plurality of obtuse bends.
7. The suspension of Claim 6 including one or more bushings carried by the chassis for closely en-gaging the torsion bar, each bushing having an inner rounded bar engaging surface to allow the bushing to slide past bends in the bar.
8. The suspension of Claim 7 wherein the ra-dius of the rounded bar engaging surface is equal to or less than the radius of the bends in the torsion bar
9. The suspension of Claim 6 wherein said inner surface is comprised of a plurality of flat sur-faces which approximate a curvature having a radius equal to or less than the radius of the bends in the torsion bar.
10. A torsion bar suspension for a snowmobile of the type having a chassis and two front skis, com-prising:
means for independently and rotatably mounting each ski to the chassis so that each ski independently and resiliently recoils ver-tically in response to uneven terrain, the skis being rotatable with respect to the mounting means for steering the snowmobile, the mounting means including, for each ski:
a mounting column extending generally ver-tically from the ski;
a pair of transverse parallel pivot bars, each pivotally attached at one end to the chassis and at the other end to the mounting column, the pivot bars allowing generally ver-tical movement of the column with respect to the chassis; and a trailing arm extending rearwardly from the mounting column and pivotally attached at its rearward end to the chassis, the trailing arm allowing generally vertical movement of the column and having a longitudinal channel there-in;
a torsion bar for biasing the mounting means of each ski vertically in response to vertical movement of the mounting means of the other ski, the torsion bar having a circular cross-section and including:
a central portion extending laterally across the chassis;
a lever portion extending laterally and forwardly from each end of the central portion and forming an obtuse angle there-with; and a mounting means engaging portion extending from the outward end of each lever portion, the axes of the engaging portions being oriented generally parallel to the axis of the central portion; and a sliding insert carried by the mounting means and having a lateral hole for closely receiving the engaging portion of the torsion bar, the hole allowing rotation and lateral translation of the bar with respect to the insert, the insert itself being permitted limited relative longitudinal movement with respect to the mounting means, and thereby permitting similar longitudinal movement of the engaging portion of the torsion bar.
means for independently and rotatably mounting each ski to the chassis so that each ski independently and resiliently recoils ver-tically in response to uneven terrain, the skis being rotatable with respect to the mounting means for steering the snowmobile, the mounting means including, for each ski:
a mounting column extending generally ver-tically from the ski;
a pair of transverse parallel pivot bars, each pivotally attached at one end to the chassis and at the other end to the mounting column, the pivot bars allowing generally ver-tical movement of the column with respect to the chassis; and a trailing arm extending rearwardly from the mounting column and pivotally attached at its rearward end to the chassis, the trailing arm allowing generally vertical movement of the column and having a longitudinal channel there-in;
a torsion bar for biasing the mounting means of each ski vertically in response to vertical movement of the mounting means of the other ski, the torsion bar having a circular cross-section and including:
a central portion extending laterally across the chassis;
a lever portion extending laterally and forwardly from each end of the central portion and forming an obtuse angle there-with; and a mounting means engaging portion extending from the outward end of each lever portion, the axes of the engaging portions being oriented generally parallel to the axis of the central portion; and a sliding insert carried by the mounting means and having a lateral hole for closely receiving the engaging portion of the torsion bar, the hole allowing rotation and lateral translation of the bar with respect to the insert, the insert itself being permitted limited relative longitudinal movement with respect to the mounting means, and thereby permitting similar longitudinal movement of the engaging portion of the torsion bar.
11. The suspension of Claim 10 including one or more bushings carried by the chassis for closely engaging the torsion bar, each bushing having a generally rounded bar engaging surface to allow the bushing to slide past bends in the bar, the radius of said surface being equal to or less than the radius of the bends in the torsion bar.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US64656784A | 1984-08-30 | 1984-08-30 | |
| US646,567 | 1984-08-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1227823A true CA1227823A (en) | 1987-10-06 |
Family
ID=24593549
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000473450A Expired CA1227823A (en) | 1984-08-30 | 1985-02-01 | Snowmobile torsion bar suspension |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1227823A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6009966A (en) * | 1997-10-09 | 2000-01-04 | Polaris Industries Inc. | Snowmobile front suspension system |
| US6125958A (en) * | 1997-10-09 | 2000-10-03 | Polaris Industries Inc. | Snowmobile front suspension |
| US6253867B1 (en) | 1998-04-24 | 2001-07-03 | Lillbacka Jetair Oy | Snowmobile suspension system |
| US6311798B1 (en) | 1999-11-19 | 2001-11-06 | Polaris Industries Inc. | Snowmobile with adjustable width front suspension |
| US6343666B1 (en) | 1997-10-09 | 2002-02-05 | Polaris Industries Inc. | Snowmobile front suspension |
-
1985
- 1985-02-01 CA CA000473450A patent/CA1227823A/en not_active Expired
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6009966A (en) * | 1997-10-09 | 2000-01-04 | Polaris Industries Inc. | Snowmobile front suspension system |
| US6125958A (en) * | 1997-10-09 | 2000-10-03 | Polaris Industries Inc. | Snowmobile front suspension |
| US6328124B1 (en) | 1997-10-09 | 2001-12-11 | Polaris Industries Inc. | Snowmobile front suspension |
| US6343666B1 (en) | 1997-10-09 | 2002-02-05 | Polaris Industries Inc. | Snowmobile front suspension |
| US6253867B1 (en) | 1998-04-24 | 2001-07-03 | Lillbacka Jetair Oy | Snowmobile suspension system |
| US6401852B2 (en) | 1998-04-24 | 2002-06-11 | Lillbacka Jetair Oy | Snowmobile suspension system |
| US6311798B1 (en) | 1999-11-19 | 2001-11-06 | Polaris Industries Inc. | Snowmobile with adjustable width front suspension |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |