Abstract:
This invention generally relates to track systems and traction assemblies for use as wheel replacement for wheeled vehicles. The track system uses a traction band disposed about a sprocket wheel, idler wheels and a road wheels for propulsion. The idler wheels and road wheels are typically pivotally mounted to a support frame, itself configured to be movably coupled to the vehicle frame via a support member. The track system can be adjustably spaced from the vehicle frame by selectively inserting one or more spacing elements between the sprocket wheel and the axle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present patent application claims the benefits of priority of U.S. Provisional Patent Application No. 61/076,531, entitled “Adjustable Width Track System” and filed at the United States Patent and Trademark Office on Jun. 27, 2009, the content of which is incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to track systems and traction assemblies used as wheel replacement for typically wheeled vehicles. More particularly, the present invention relates to track systems and traction assemblies for use on heavy vehicles such as, but not limited to, farming and agricultural vehicles (e.g. tractors, harvesters, etc.) and construction and industrial vehicles (e.g. excavators, combines, forestry equipments). 
       BACKGROUND OF THE INVENTION 
       [0003]    Soil compaction and flotation have always been important issues for farmers operating tractors and other farming vehicles in their fields. Having a tractor equipped with track systems assures lower ground pressure, better traction and better use of the available power. This is particularly important in row-crop production where the width of the track is required to be as thin as possible to maximize the production. Rolling with thin tires affects the ground pressure which validates the need for tracks. 
         [0004]    However, the row-crop industry is not managed by standards. Each farmer typically chooses his row width which may vary even within some of his fields. To help these farmers with a track-based solution, custom track systems are typically required for each width required by the farmers. Custom track systems are however inherently costly. 
         [0005]    Solutions have been proposed to provide width adjustability to track systems. However, these track systems are typically complex, difficult to repair and hard to steer and operate. 
         [0006]    Hence, despite ongoing development in the field of track systems, there is still a need for a novel track system which mitigates the drawbacks of prior track systems while still providing the ability to select the width thereof. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention therefore provides a solution to the shortcomings of the prior art by providing a novel track system which can be adjustably and selectively spaced from the vehicle frame to which it is mounted. 
         [0008]    In accordance with the principles of the present invention, the track system generally comprises a sprocket wheel configured to be mounted to one of the wheel axles of the vehicle, a support frame movably coupled to the frame of the vehicle via a support member preferably mounted near the wheel axle, and generally independently of the sprocket wheel, and a longitudinally extending endless traction band mounted thereabout. The support frame typically pivotally supports wheels such as idlers wheels mounted at the fore and at the aft, and road wheels mounted along the length thereof. 
         [0009]    In accordance with the present invention, the track system is further provided with at least one and preferably a plurality of spacing elements, typically embodied as spacer rings or segments, each having a predetermined thickness. The spacing elements are mounted in cooperation with the sprocket wheel and can be selectively mounted on the inner side or on the outer side thereof. The spacing elements mounted on the inner side of the sprocket wheel become effectively lodged between the sprocket wheel and the wheel axle and space the sprocket wheel, and thus the track system, from the vehicle frame. By selecting a particular combination of spacing elements to be mounted between the sprocket wheel and the wheel axle, the space between the sprocket wheel and the vehicle frame, and thus the effective width of the track system can be changed. 
         [0010]    Similarly, the support frame is pivotally mounted to the support member via a laterally extending rod to which are also mounted corresponding spacing elements, preferably embodied as spacer rings or segments. Though generally smaller in diameter than the spacing elements of the sprocket wheels, the spacing elements of the support frame are preferably provided in same number with same thickness to provide corresponding spacing. 
         [0011]    As for the spacing elements of the sprocket wheel, the spacing elements of the support frame can be selectively mounted on the inner side or on the outer side of the support frame. 
         [0012]    Preferably, symmetric track systems are respectively mounted on each side of the vehicle. Thus, by selectively adjusting the space between each sprocket wheel and the vehicle frame, and between the support frame and support member, the overall width of the vehicle can be selectively adjusted using simple spacing elements. 
         [0013]    In accordance with the present invention, the spacing elements can be provided in different numbers and/or in different thicknesses depending on the size and configuration of the track systems and depending on the required precision of the spacing. Still, by selectively combining the spacing elements of the sprocket wheel and of the support frame, many spacing configurations can be achieved. Hence, the track system of the present invention can achieve different over width configurations without the need for custom pieces. 
         [0014]    Though the present invention is particularly useful for track systems used on farming and generally agricultural vehicles, the present invention could also be used in the grooming industry for adaptation to the track sizes, or in the construction industry as an adjustment for added stability or increased manoeuvrability in small areas. 
         [0015]    Understandably, other advantages and novel features of the present invention will be obvious upon an understanding of the illustrative embodiments about to be described by reference to the following detailed description and considered in connection with the accompanying drawings in which like reference symbols designated like elements throughout the figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The above and other objects, features and advantages of the invention will become more readily apparent from the following description, reference being made to the accompanying drawings in which: 
           [0017]      FIG. 1  is a cross-section view of an exemplary track system in accordance with the present invention, in a retracted position, without an endless traction band, and as mounted to the rear axle of a vehicle. 
           [0018]      FIG. 2  is a cross-section view of the track system of  FIG. 1 , in extended position, without an endless traction band, and as mounted to the rear axle a vehicle. 
           [0019]      FIG. 3  is a perspective view of the track system illustrated in  FIG. 1 . 
           [0020]      FIG. 4  is a perspective view of the track system illustrated in  FIG. 2 . 
           [0021]      FIG. 5  is a perspective view of the track system of  FIG. 2 , with an endless traction band mounted thereon. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    A novel track system will be described hereinafter. Although the invention is described in terms of specific illustrative embodiments, it is to be understood that the embodiments described herein are by way of example only and that the scope of the invention is not intended to be limited thereby. 
         [0023]    The present invention will be illustrated using an exemplary track system generally illustrated in  FIGS. 1 to 5 . Though not shown, the track system of the present invention is typically used in pair wherein symmetrical track systems are mounted to the wheel axle on each side of the vehicle. 
         [0024]    Referring now to  FIGS. 1 to 5 , the track system  10  will be described in more details. 
         [0025]    The track system  10  typically comprises a sprocket wheel  100  adapted to be mounted to the wheel axle  30  (or wheel hub) of a vehicle (not shown). The track system  10  also comprises a support structure  200  mounted to the frame  20  of the vehicle. The support structure  200  is generally provided with wheels  300  such as idler wheels  310  pivotally mounted at the fore or front portion thereof and at the aft or rear portion thereof, and road wheels  350  pivotally mounted along the length thereof. Disposed around the sprocket wheel  100 , the support structure  200 , and wheels  300  is a longitudinally extending endless traction band  400  preferably made of reinforced elastomeric material. 
         [0026]    Referring now to  FIGS. 3 and 4 , the sprocket wheel  100  of the track system  10  is illustrated in more details. The sprocket wheel  100  generally comprises a plurality of generally evenly spaced and axially extending sprocket teeth  112  located at the periphery thereof. The sprocket teeth  112  are configured to drivingly engage drive lugs (not shown) longitudinally disposed on the inner surface of the traction band  400 . 
         [0027]    As shown in  FIGS. 3 and 4 , the sprocket wheel  110  is preferably composed of several (e.g. four (4) in the present embodiment) arcuate peripheral sprocket portions  111 , a support ring  113 , and a central disk  115 . 
         [0028]    As depicted in  FIGS. 1 and 2 , the central disk  115  of the sprocket wheel  100  is configured to be mounted on the axle  30  (or wheel hub, not shown) of the vehicle with fasteners known in the art. The central disk  115  is provided, at its outer periphery, with openings configured to receive fasteners. 
         [0029]    Mounted to the outer periphery of the central disk  115  is the support ring  113 . The support ring  113  is typically secured to the central disk  115  with fasteners such as nuts and bolts assemblies. 
         [0030]    For their parts, the peripheral portions  111  are mounted at the outer periphery of the support ring  113  using fasteners such as nuts and bolts assemblies. As best illustrated in  FIG. 3 , consecutive peripheral portions  111  are typically further secured together via attaching plates  117  and fasteners such nuts and bolts assemblies. 
         [0031]    As this point, the skilled addressee will understand that the sprocket wheel  100  illustrated in the figures is a preferred embodiment. In fact, even though the central disk  115  and the support ring  113  have been shown as unitary components, and the peripheral portions  111  as split components, different sprocket wheel configurations could allow for a unitary peripheral portion  111  and/or for a split central disk  115  and/or a split support ring  113 . Moreover, the peripheral sprocket portion(s)  111  and the support ring  113  could also be unitary. The present invention is understandably not so limited. 
         [0032]    Referring now to  FIGS. 1 to 4 , in order to provide width adjustability to the track system  10 , the sprocket wheel  100  is provided with spacing elements  130 . The spacing elements  130  are generally embodied as rings or arcuate segments having predetermined thicknesses. As best shown in  FIGS. 1 and 2 , the spacing elements  130  are configured to be mounted on an outer side and/or an inner side of the support ring  113 . 
         [0033]    In  FIG. 1 , all the spacing elements  130  are mounted on the outer side of the support ring  113  and the sprocket wheel  100  is correspondingly closer to the vehicle frame  20 . In  FIG. 2 , all the spacing elements  130  are mounted on the inner side of the support ring  113  and the sprocket wheel  100  is correspondingly spaced away from the vehicle frame  20 . As the skilled addressee will understand, and as best illustrated in  FIGS. 2 and 4 , when spacing elements  130  are mounted on the inner side of the support ring  113 , they become effectively lodged between the support ring  113  and the central disk  115 . 
         [0034]    The added thickness caused by the spacing elements  130  located between the support ring  113  and the central disk  115  effectively pushes the track system  10  further away from the vehicle frame  20 , effectively changing the overall width of the track system  10 . 
         [0035]    Notably, though in  FIGS. 1 and 2 , the spacing elements  130  are either all located on the outer side of the support ring  113  ( FIG. 1 ) or on the inner side thereof ( FIG. 2 ), it is to be understood that only a subset of the spacing elements  130  could be mounted between the support ring  113  and the central disk  115 , the remaining spacing elements  130  being left mounted on the outer side of the support ring  113  for possible future use. Hence, depending on the required width of the track system  10 , the required number of spacing elements  130  mounted between the support ring  113  and the central disk  115  could vary. 
         [0036]    In addition, even though the spacing elements  130  shown in  FIGS. 1 and 2  are all of similar thickness, spacing elements  130  having different thicknesses are possible. In that sense, set of spacing elements  130  having different thicknesses could be provided with the track system for providing several width configurations. The user would then select only the spacing elements  130  providing the desired spacing. 
         [0037]    Referring back to  FIGS. 3 and 4 , the support structure  200  of the track system  10  will be described in more details. 
         [0038]    Support structure  200  typically comprises a support frame  210  pivotally mounted to a support member  250 , the support member  250  being fixedly mounted to the frame  20  of the vehicle via conventional brackets and fasteners. 
         [0039]    As best depicted in  FIGS. 3 and 4 , the support frame  210  is preferably longitudinally extending and pivotally supports idler wheels  310  at its fore portion  211  and aft portion  213 , and road wheels  350  along its length. The support frame  210  is preferably further provided with tensioning mechanism  215  such as a conventional push-bolt tensioner for adjusting the tension of the traction band  400  through the front or rear idler wheels  310 . The support frame  210  is also advantageously provided with scraping blades  217  for removing debris lodged on and/or between the idler wheels  350 . 
         [0040]    For its part, and as shown in  FIGS. 1 and 2 , the support member  250  is typically composed of a lower portion  253  typically located underneath the sprocket wheel  100 , and an upper portion  255  configured to be fixedly mounted to the vehicle frame  20 . 
         [0041]    As best illustrated in  FIGS. 1 and 2 , the support frame  210  is pivotally coupled to the lower portion  253  of the support member  250  through a laterally extending rod  251  fixed to the lower portion  253 . Notably, the axis of rotation  252  of the support frame  210  with respect to the rod  251  is located lower than the axis of rotation  102  of the sprocket wheel  100 , allowing the support frame  210  to pivot independently of the sprocket wheel  100 . 
         [0042]    Referring now to  FIGS. 3 and 4 , the lower portion  253  of the support member  250  is advantageously provided with laterally extending blocking rods  257  located before and behind the rod  251 . These blocking rods  257  are configured to prevent excessive rotation of the support frame  210  with respect to the rod  251 . In case of excessive rotation, the support frame  210  will abut on either one of the blocking rods  257  and damages to the sprocket wheel  100  will be prevented. 
         [0043]    Referring back to  FIGS. 1 and 2 , the support frame  210  is also slidingly mounted to the rod  251 . Indeed, since the sprocket wheel  100  can be more or less spaced from the frame  20  of the vehicle via the use of spacing elements  130 , and since the traction band  400  is disposed around both the sprocket wheel  100  and the support frame  210 , the support frame  210  must be laterally displaceable along rod  251  to remain aligned with the sprocket wheel  100 . However, to prevent unwanted movements of the support frame  210  along the rod  251 , spacing elements  230  are disposed on the inner side ( FIG. 2 ) and/or the outer side ( FIG. 1 ) of the support frame  210 . 
         [0044]    Spacing elements  230  are preferably embodied as spacer rings. Spacing elements  230  are preferably slidingly mounted to the rod  251  and are lodged, on the inner side, between the support frame  210  and a shoulder  259  formed in rod  251 , and on the outer side, between the support frame  210  and a side plate  213  fixed to rod  251  by a bolt. 
         [0045]    The skilled addressee will understand that the spacing defined by the combination of spacing elements  130  mounted between the support ring  113  and the central disk  115  should be equal to the spacing defined by the combination of spacing elements  230  mounted between the support frame  210  and the support member  250  in order to keep the traction band  400  aligned. 
         [0046]    It is to be noted that the spacing elements  130  and  230  may be provided in a plurality of thickness. It is thus possible to use one set of spacing elements  130  and  230  having the desired dimensions or to use a combination of spacing elements  130  and  230  giving the same desired dimensions. For example, to space the track system  10  about four inches on one side of the vehicle, a user could use a spacing element  130  four inches thick and two spacing elements  230  two inches thick, or even four pairs of spacing elements  130  and  230  one inch thick. Other combinations are understandably possible. 
         [0047]    Typically, but not necessarily, track systems  10  mounted on each side of a vehicle will be spaced symmetrically. Still, a track system  10  mounted on one side could be spaced differently then the opposite track system  10  mounted on the other side if necessary or practical. The present invention allows such possibilities. 
         [0048]    While illustrative and presently preferred embodiments of the invention have been described in detail hereinabove, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.