Abstract:
Metallic clips are provided on the endless track of a snowmobile equipped with one or more elongated slide runners forming part of its suspension system. The clips are formed with a first portion adapted to be slidably and frictionally contacted by the slide runners during rotation of the track and with a second portion extending slightly above profiles integrally formed on the outer surface of the track so that heat generated as a result of the sliding friction of the runners on the clips is transferred directly to the snow or ice over which the snowmobile travels so as to cool the clips.

Description:
FIELD OF THE INVENTION 
     The present invention pertains to an endless track for use on a snowmobile equipped with a suspension system having elongated slide runners which bear on the inner face of the lower run of the track. More particularly, the present invention relates to such tracks having metallic clips that provide a bearing contact for the slide runners on the track. 
     BACKGROUND OF THE INVENTION 
     Many snowmobile tracks are presently equipped with metallic clips which are located in one or more rows of longitudinally spaced openings provided along the endless track. The purpose of these clips is to provide a sliding surface for the slide runners that bear on the inner face of the lower run on the track. The highly rotational drive of the track causes extreme heat to be generated on the contacting surfaces of the slide runners and of the clips. This heat is transferred to the rubber material of the track onto which the metallic elements are clipped, greatly affecting its structure. In some cases, the heat will cause the runners to be bound to the clips. 
     In tracks having one or more rows of openings, there is a cooling effect obtained by the presence of snow or ice in these holes in which extend opposite wing portions of the clips. However, this cooling has been found to be greatly insufficient and the above described heat problems still exist. 
     OBJECTS AND STATEMENT OF THE INVENTION 
     It is an object of the present invention to provide, on an endless track of a snowmobile of the kind having slide runners forming part of the suspension system, a series of metallic clips which establish a direct contact between the slide runners and the snow or ice over which the snowmobile travels so that the heat generated by the sliding friction of the slide runners on the metallic clips may be thermally transferred directly to the snow or ice, which is obviously at a much lower temperature than that of the heat generated by the sliding friction. 
     The present invention therefore relates to a track for use on a snowmobile having a suspension system equipped with one or more elongated slide runners, the track comprising an endless body having an outer surface with transverse rows of ground engaging profiles, spaced longitudinally of the track, and an inner surface adapted to receive, on the lower run thereof, the slide runners of the suspension system. The track includes one or more rows of longitudinally spaced metal clips that are secured to the body of the track; each clip has a first flat portion extending substantially in the plane of the inner surface of the track and so disposed thereon as to be frictionally contacted by a slide runner, and a second portion extending above the outer surface of the track so as to contact the ground over which the snowmobile travels whereby heat generated by the frictional sliding contact of the slide runner on the first portion of the clip is thermally transferred to the ground, being at a temperature lower than that of the heat generated by the frictional sliding contact of the slide runners on the clips. 
     In one form of the invention, each clip is formed of a slide contacting first part that includes the first flat portion and of a ground engaging second part that includes the second portion. Each first part has hook ends engaging corresponding hook ends on the second part to inter-engage these parts to one another. 
     In another form of the invention, each clip is formed of a single body with the second portion being formed of a bottom wall that includes the first portion and of folded side and top walls that define the second portion. 
     In another form of the invention, the second portion of the clip includes pointed studs that extend beyond a plane that includes the top edges of the profiles of the track. 
     In another form of the invention, the pointed studs are integrally formed to a top face of the second portion. 
     In a further form of the invention, the pointed studs are securely fixed to top walls of the second portion of the clip. 
     Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that this detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a clip made in accordance with the present invention; 
     FIG. 2 is a top perspective view showing part of a snowmobile track equipped with clips such as shown in FIG. 1; 
     FIG. 3 is a cross-sectional view taken along line  3 — 3  of FIG. 2; 
     FIG. 4 is a cross-sectional view taken along line  4 — 4  of FIG. 3; 
     FIG. 5 is a perspective view of another embodiment of a clip made in accordance with the present invention. 
     FIG. 6 is a top perspective view showing the clip of FIG. 5 mounted on a snowmobile track shown in part. 
     FIG. 7 is a cross sectional view taken along line  7 — 7  of FIG. 6; 
     FIG. 8 is a cross sectional view taken along line  8 — 8  of FIG. 7; and 
     FIG. 9 is a perspective view showing another embodiment of a clip made in accordance with the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 and 2, there is shown a metallic element in the form of a clip, generally denoted  10 , which is shaped to form part of a snowmobile endless track, generally denoted  12 , made in accordance with the present invention. 
     Referring also to FIGS. 3 and 4, the snowmobile track  12  comprises an outer surface  14  and an inner surface  16 . The outer surface comprises a series of transverse rows, (three being shown as  18 ,  20  and  22 ) which are longitudinally spaced along the endless track. The profiles have different forms to provide ground traction to the track when driven by the transmission system of a snowmobile (not shown). 
     The inner face  16  of the track comprises a series of lugs, such as those illustrated as  24  and  26 , which are adapted to be contacted by drive sprockets (not shown) forming part of the driving system of the snowmobile. 
     The suspension system of a snowmobile usually consists of a pair of longitudinal slide runners that bear on the lower run of the inner face  16  of the snowmobile track. They are usually located over areas of the track where a series of openings, such as  30  and  32 , are provided. 
     On most snowmobile tracks, the metallic elements are clipped onto the rubber material that form part of the profiles. In some tracks, the clips are present at every second, third or more profile. Reinforcing rods  34  usually extends transversally of the track within the profiles. The construction of a snowmobile track is well known and a detailed description of its method of manufacturing needs not be described. It should be mentioned however that, in a co-pending U.S. application of applicant, filed Jan. 10, 2000 under Ser. No. 09/480,152 a new method of making a snowmobile track is described where the metallic elements are not clipped on the tracks after the track is vulcanized and cured, but where they are integrally formed to the track prior to the vulcanizing and curing steps. 
     In all known snowmobile tracks, the metallic elements, whether clipped or integrally formed, have a portion extending near the plane of the inner surface of the track and opposite wing portions extending in the opening of the back that are clipped or integral with opposite sides of the profiles; however, they terminate short of the top edge thereof. The slide runners bear and slide along the outer face of the portions of the metallic elements that lie near the plane of the inner surface of the track. During operation of the snowmobile, frictional heat is generated by the contacting surfaces of the clips and the runners. 
     The present invention is concerned with means for dissipating this heat from the slide runners to the ground, such as snow or ice, over which the snowmobile travels. 
     The embodiment  10  illustrated in FIG. 1 consists of a two-part clip which achieves the intended purpose of the present invention; thus, the clip  10  comprises a lower part  50  and an upper part  52  (the terms “lower” and “upper” are used for the parts as they are seen in the drawings). As can be seen in FIG. 4, the lower part  50  comprises a flat horizontal portion  56  and a pair of opposite hook ends  58  and  60 . 
     The upper part  52  comprises a top face  62  that lies over the top edge of the profile  20  and opposite side portions  64  and  66  which follow generally the contour of the profile and which display lower hook ends  68  and  70 . The latter are shaped to lockingly engage with the hook ends  58  and  60  of the lower part  50  of the clip. The top portion  62  has opposite triangular shaped pointed ends  70  and  72  forming studs which extend beyond a plane that extends through the top edges  18 ′,  20 ′ and  22 ′ of the profiles  18 ,  20  and  22 . 
     The lower part  50  has a downwardly curved end portion  80  which is adapted to bear against the side face of a lug  24  on the inner surface of the track. 
     Both parts  50  and  52  have, on opposite sides thereof, one or more bosses  90 ,  92  that fittedly engage one another to further secure the inter-engagement of the two parts when hooked to one another. 
     Referring to FIG. 4, it can be seen that the heat generated by the frictional contact of a slide runner on surface  56  of the lower part  50  of the clip will be thermally transferred to the upper clip part  52  and to its pointed ends  70 ,  72  which will contact the ice or snow whereby the clips will be cooled. 
     The embodiment  110  illustrated in FIG. 5 also consists of a two-part clip including a lower part  150  and an upper part  152 . Referring also to FIG. 6, the clip  110  is provided on a profile portion  112  of a snowmobile track  114  between two longitudinally spaced opening  116  and  118  in the manner shown. 
     Referring to FIGS. 7 and 8, the lower part  150  comprises a flat horizontal portion  156  and a pair of opposite hook ends  158  and  160 . The part  152  comprises a pair of opposite faces  161 ,  162  that lye over the top edge of the profile portion  112  of the track. The upper part also includes opposite side portions  164 ,  166  which follow generally the contour of the profile and which display lower hook ends  168  and  170  respectively. The latter are shaped to lockingly engage with the hook ends  158  and  160  of the lower part  150  of the clip. The top faces  161  and  162  each display a pointed stud  170  and  172  which extend beyond a plane that includes the top edge of the profile section of the track. 
     The lower part  150  has a downwardly curved end portion  180  which is adapted to bear against the side face of a lug  124  on the inner surface of the track. 
     The lower part  150  has on its opposite side walls  182  and  184  deformable sections  186  and  188  which, when deformed inwardly as illustrated in FIG. 8, secure the inter-engagement of the lower part  150  with the upper part  152 . 
     Again, in this embodiment, it can be seen that the heat generated by the frictional contact of a slide runner on the surface  156  of the lower part  150  of the clip will be thermally transferred to the upper clip part  152  and to its pointed studs  170  and  172  which will contact the ice or snow whereby the clips will be cooled. 
     FIG. 9 shows another embodiment  210  of a clip made in accordance with the present invention; however, this clip is formed of a single body having a bottom wall  212 , a pair of side walls  214 ,  216  which have their upper ends folded to define a two-layer top wall  218 . The bottom wall  212  has an undersurface which is adapted to be contacted by the slide runner of a snowmobile and a curved end portion  220  to contact the lug of the track used for driving the track. In this embodiment, the clip is secured to the material of the track which extends within the walls  212 ,  214 ,  216  and  218 . A pair of pointed studs  222  and  224  are fixedly secured to the top wall  218  of the clip to contact the snow or ice over which the snowmobile travels and also to provide a traction. 
     Although the invention has been described in relation to three specific forms, it will be evident to the person skilled in the art that it may be modified and refined in various ways. It is therefore wished to have it understood that the present invention should not be limited in scope, except by the terms of the following claims.