Patent Publication Number: US-2023159118-A1

Title: Track system for a vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a Continuation application of U.S. patent application Ser. No. 16/193,302 filed Nov. 16, 2018, entitled “Track System For A Vehicle”. Through the application Ser. No. 16/193,302, the present application claims priority to the U.S. Provisional Patent Application Ser. No. 62/588,872, filed Nov. 20, 2017, entitled “Track System For A Vehicle”. Both applications are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present technology relates to track systems for vehicles. 
     BACKGROUND 
     Certain vehicles, such as, for example, vehicles used in agriculture (e.g., harvesters, combines, tractors, etc.) construction, forestry, mining and powersports, are used to perform work on ground surfaces that are soft, slippery and/or uneven (e.g., soil, mud, sand, ice, snow, etc.). 
     Such vehicles may be equipped with towable implements used to perform agricultural work (e.g. seeding, spraying, harvesting, etc.). For simplicity, “vehicle” will be used herein as referring to either or both such vehicle and such implements. 
     Conventionally, such vehicles have had ground engaging assemblies each comprising a wheel mounted with a tire to operate the vehicle along the ground surface. Under certain conditions, such assemblies may have poor traction and stability on some kinds of ground surfaces. As such vehicles are generally heavy, the tires may compact the ground surface under an adversely high pressure owing to the weight of such vehicles being concentrated over a limited ground engaging contact patch area. As an example, when the vehicle is an agricultural vehicle, the tires may compact the soil in such a way as to undesirably inhibit the growth of crops. Furthermore, stability issues due to poor floatation over a ground surface that is uneven or yielding under such pressure may damage the vehicle (e.g. a spray boom extremity colliding with the ground surface) or reduce the quality of the work being performed (e.g. uneven spraying of pesticides). 
     In order to reduce the aforementioned drawbacks, it was deemed desirable to increase stability and traction by distributing the weight of the vehicle across a larger ground engaging contact area on the ground surface, and track systems were developed to be used as ground engaging assemblies in place of at least some of the wheels and tires on the vehicles. 
     The use of track systems in place of wheels and tires, however, does present inherent inconveniences. One of the drawbacks of conventional track systems is that they tend to impart an operatively attached vehicle with an increased amount of vibration when operated on uneven ground surfaces due to the loss of the damping otherwise provided by a tire. In addition to potentially increased operator discomfort, these vibrations can potentially lead to premature wear and failure of components of the vehicle (e.g. track system, drive axle assembly, agricultural equipment, etc.). Under certain conditions and at certain increased speeds, the resulting increased vibrations transferred to the chassis may render the vehicle less effective or even unusable for its intended purpose. 
     Some technologies related to the same technical field may conventionally result in appreciable reduction of the vibration transmitted to a vehicle operatively attached to a track system having an arrangement of damping elements. For instance, such an arrangement may be in the form of resilient elements distributed at the interface of the track system with the vehicle chassis, such as the technology shown in CA 2,546,120. Among other alternatives such as seen in U.S. Pat. No. 5,899,542 and in US 2007/0029871 A1, damping elements may be present on track systems in the form of resilient elements distributed at the interface of the support frame and bogies. Such bogies may be displaced to overcome small ground surface irregularities (e.g. bumps and crevices) when biased by the underlying portion of the endless track entering contact with such irregularities. 
     Although convenient when operated onto uneven ground surfaces, such improvements may not effectively mitigate the transmission of movements of greater amplitude from a track system to an operatively attached vehicle, as may occur when the vehicle is operated onto a further uneven ground surface having more pronounced irregularities (e.g. slopes, trenches, large rocks, etc.). In such conditions, stability and traction may still be improved. 
     Accordingly, track systems may be designed to have a pivotable range of motion. Such track systems may be structured and arranged to have a sprocket wheel that is drivingly attachable to a vehicle&#39;s drive axle assembly, a support frame that is pivotably attached to the same vehicle drive axle assembly, the support frame having roller wheels and idler wheels rotatably attached to leading and trailing portions of the support frame, defined by the portions in front of and behind the sprocket wheel rotation axis, and an endless track extending around the sprocket wheel, roller wheels and idler wheels. Such track systems may be pivotally displaced to overcome large ground surface irregularities when biased by a portion of the endless track underlying a portion of the support frame enters contact with such surface irregularities. Via a suspension assembly linking the support frame to the chassis of the vehicle, the rotational position of the support frame is generally biased into a neutral position when the track system operated over an even ground surface and limited in range when the track system is operated onto an uneven ground surface. 
     Such track systems typically require that the drive axle assembly of the vehicle be structured to withstand a greater and more concentrated load due to the support frame not being fixedly attached to the chassis of the vehicle. For similar load distribution purposes, the support frame of such track systems may have portions that are rotatably attached to two portions of the drive axle of the vehicle, longitudinally spaced apart from an outward facing side and from an inward facing side of the sprocket wheel, respectively. 
     Also, track systems known in the art may benefit from a “split frame” configuration, as shown in U.S. Pat. No. 5,452,949. Such track systems typically comprise a support frame from which downwardly extend two pivotably attached frame members. The leading and trailing members respectively extend frontward and rearward of the support frame, and are pivotably attached thereto either via their own pivot or via a common pivot. Via a suspension assembly linking each member to the support frame, the rotational position of such members is generally biased into a neutral position when the track system is operated over an even, leveled ground surface and the rotational displacement of such members is generally limited in range when the track system is operated onto an uneven ground surface. Leading and trailing members further have a bogie assembly including rotatably attached roller wheels and idler wheels. Bogie assemblies may be fixedly or rotatably attached to a member and may feature damping elements. Advantageously, such track systems may provide reduced transmission of movements from the track system to the vehicle, with vibrations and movements of small amplitude being mitigated by the bogie assemblies, and movements of larger amplitude being mitigated by the “split frame” arrangement of the support frame. Moreover, such systems may have a support frame having a static portion that includes frame portions that are fixedly attachable to the chassis of the vehicle, which may improve load distribution at the interface of the track system and the vehicle. However, this improvement typically comes at the cost of a reduced capacity for the track system to mitigate vibrations and movements, due to the range of motion of movable parts (e.g. leading and trailing members) being hindered by the static parts. 
     While the technology described above may indeed ameliorate some of the drawbacks of conventional track systems, further improvements in this field remain desirable. 
     SUMMARY 
     It is therefore an object of the present technology to ameliorate the situation with respect to at least one of the inconveniences present in the prior art. 
     It is also an object of the present invention to provide an improved track and suspension system at least in some instances as compared with some of the prior art. 
     According to an aspect of the present technology, there is provided a track system for use with a vehicle having a chassis and an axle assembly extending laterally outward from the chassis suitable for rotatable connection with the track system. In the context of the present technology, an “axle” of the vehicle shall be understood to be either a “drive axle” or a “dead axle”, and either a “straight” axle or a “split axle”. A “drive axle” is a vehicle component that ultimately transmits torque generated by the engine to a ground engaging assembly of the vehicle (e.g. a wheel assembly when such is connected to the vehicle or a track system when such is connected to the vehicle, etc.). A “dead axle” is a vehicle component that is not imparted with torque generated by the engine, yet is rotatably connected to the ground engaging assembly of the vehicle for operating and load-bearing purposes. A “straight axle” is a vehicle component that comprises a single shaft that is rotatably connectable to a ground engaging assembly positioned on the left side of the vehicle and to a ground engaging assembly positioned on the right side of the vehicle. A “split axle” is a vehicle component that comprises a left shaft and a right shaft that are rotatably connectable to a ground engaging assembly positioned on the left side of the vehicle and to a ground engaging assembly positioned on the right side of the vehicle, respectively. A “split axle” allows the use of independent suspension systems or differential systems in conjunction with a vehicle&#39;s ground engaging assemblies. Various axle configurations can be used in the context of the present technology. As vehicle axles are not central to the present technology, they will not be described in further detail. 
     The track system includes an attachment assembly that is fastenable to an outward facing, ground-oriented portion of the chassis of the vehicle. The attachment assembly is structured and dimensioned to be received on the chassis at the intersection of the longitudinal midline of the chassis and of the axle of the vehicle to which the track system is drivingly attachable. The attachment assembly also has a central portion and lateral portions extending laterally outwardly from the central portion. 
     The central portion has a longitudinally aligned depressed portion that has a front tab and a rear tab both adapted to receive fasteners, and respectively extend forward and rearward from the axle of the vehicle to which the track system is drivingly attachable. The central portion further has a laterally oriented raised portion that has left and right fastening interfaces disposed on both sides of the longitudinal midline of the attachment assembly. The lateral portions have track assembly abutting walls oriented outwardly, with concentrically-aligned pivot cylinders extending therefrom. In the context of the present technology, “track assembly” shall be understood to be the ground-engaging sub-assembly of track system elements of which a pair is disposed and attached bilaterally outwardly from the attachment assembly. The attachment assembly also includes receiving portions adapted to interface with portions of an attached chassis of the track assemblies, thereby blocking degrees of freedom and distributing loads therefrom. The central portion has a chassis receiving portion shaped as a longitudinal cavity in the depressed portion which extends through the raised portion forming a channel, and a plurality of chassis receiving portions shaped as through and non through pockets. The lateral portions have track assembly receiving portions defining a proximal arm extending laterally and upwardly from the abutting walls and distally connected to a housing, a distal arm proximally connected thereto, extending laterally and downwardly and distally connected to a protection pad. The housing is adapted to receive a portion of the sprocket of the track system, and the pad is adapted to receive a movable portion of the support frame of the track system. 
     The track system further includes a multi-member support frame, whose configuration may also be referred to as “split-frame”. The support frame includes a leading member and a trailing member, each having an attachment portion for independently pivoting one frame member with respect to the other about the pivot cylinder, and a suspension portion for interconnecting one frame member to the other via a suspension system. In the context of the present technology, it shall be understood that “leading” elements of a track system attached to a vehicle are disposed toward the front end of the vehicle with respect to their “trailing” counterparts. The leading and trailing members of the support frame are arch-shaped, with their attachment and suspension portions, or “arms”, converging forwardly and rearwardly, respectively. 
     The leading frame member and the trailing frame member of the track system pivot one with respect to the other via their respective attachment arm. Each attachment arm is pivotably connected to the pivot cylinder of the attachment assembly via a bore of a tab of the attachment arm. Each tab has an inwardly facing wall and an outwardly facing wall, both being perpendicular to the axis of the bore. The pivot cylinder of the attachment assembly is pivotably received into the bore of the tab of the trailing attachment, and the inward-facing tab wall of the trailing attachment arm abuts the abutting wall of the attachment assembly. The pivot cylinder of the attachment assembly is pivotably received into the bore of the tab of the leading attachment arm, and the inward-facing tab wall of the leading attachment arm abuts the outward-facing tab wall of the trailing attachment arm. The tabs are positioned inwardly from the sprocket wheel. The pivot cylinder of the attachment assembly is structured and arranged such that the attached leading and trailing members each have a sole degree of freedom for pivoting independently about the pivot cylinder axis. 
     The suspension arms each have a suspension pivot, both positioned at a same horizontal distance from the longitudinal midline of the chassis of the vehicle. Also, the suspension arm pivots are projected outwardly and upwardly with respect to the attachment arm tabs in such a way that allows clearance between static elements of the track system (e.g. the sprocket wheel and the attachment assembly) and mobile elements of the track system (e.g. leading frame member, trailing frame member and suspension assembly). 
     The suspension assembly has an extendable member, a forwardmost attachment tab pivotably attached to the leading suspension pivot and a rearwardmost attachment tab pivotably attached to the trailing suspension pivot. The extendable member includes a spring and a damper. The linear displacement of the forwardmost attachment tab with respect to the rearwardmost attachment tab is dynamically determined according to the properties of the spring and damping elements in conjunction with the loading conditions imparted by an attached vehicle operated on a ground surface. In the context of the present invention, the distance between the attachment tabs of the suspension assembly varies between a maximum distance when the suspension assembly is in a deployed position and a minimum distance when the suspension assembly is in a bottomed position. 
     Each of the leading frame member and the trailing frame member have at least one ground-oriented pivot, either for the pivotable attachment of a wheel-bearing member itself having a plurality of ground-oriented pivots, or for the rotatable attachment of either an idler wheel or a roller wheel. 
     In some embodiments, the leading frame member has a pivotably attached wheel-bearing member, to which an idler wheel and a roller wheel are rotatably attached, the idler wheel being attached to the forwardmost ground-oriented pivot of the track assembly. The trailing frame member has a pivotably attached wheel-bearing member and a rotatably attached idler wheel, the wheel-bearing member having two rotatably attached roller wheels, and the idler wheel being rotatably attached to the rearmost ground-oriented pivot of the track assembly. 
     The track system further includes a sprocket wheel connected to the axle assembly of the vehicle and an endless track extending around the sprocket wheel, the wheels of the leading frame assembly and the wheels of the trailing frame assembly, the endless track engaged by the sprocket wheel. When the sprocket wheel of a track system is rotatably connected to a drive axle assembly of a vehicle operating over a ground surface, the sprocket wheel drivingly engages the endless track. When the sprocket wheel of a track system is rotatably connected to a dead axle assembly of a vehicle operating over a ground surface, the sprocket wheel passively engages the endless track. 
     The track system of the present technology is directed in part toward an improved distribution and withstanding of loads imparted by a vehicle attached thereto under certain conditions. For example, the amount of load transferred from the vehicle to the track assembly via the attachment assembly may, in certain conditions, materially reduce the load transferred from the vehicle to the track assembly via the drive interface of the sprocket wheel which may improve the effectiveness and durability of the track system. 
     Drawbacks may be found in conventional track systems designed to optimize the distribution of loads from an attached vehicle among the elements of the track system, which typically include and rely on attachments between the support frame to the drive assembly of the vehicle. Such support frame may conventionally include wheel-bearing members designed to movably and resiliently mitigate vibrations and vertical movements imparted by operating the attached vehicle over an uneven ground surface. In some circumstances, the amplitude of movement of support frame members and of wheel-bearing members may be limited by the adjacent fixed support frame attachments, and hence may not fully address operator discomfort, premature vehicle wear and counterproductive vehicle instability issues. The track system of the present technology is directed toward the mitigation of such issues. 
     For instance, the vibrations imparted to a vehicle attached to the track system and operated over a ground surface may be, under certain conditions, sufficiently dampened through the interface between the attachment assembly and the chassis of the vehicle. Furthermore, when the vehicle is operated over a ground surface having irregularities of small amplitude, the resulting vibrations may be sufficiently damped due in part by the inherent resilience of the track system. This resilience is derived from the arrangement of idler wheels and roller wheels of the track system, attached to ground-oriented pivots of leading frame members, trailing frame members and their pivotably attached wheel-bearing members, in conjunction with the materials used to manufacture such elements. 
     Advantageously, the means to attach the track assemblies of the track system to the vehicle is decoupled into a driving attachment via the drive interface of the sprocket wheel and into a load bearing attachment via the pivot cylinder of the attachment assembly. As the load bearing attachment is spaced apart and distinct from the axle assembly of the vehicle, the elements of the track system are structured and arranged one with respect to the other such that the movable elements of the system such as the leading frame member, the trailing frame member, their respective wheel-bearing members and the suspension assembly, have an optimized amplitude of movement with respect to static elements such as the sprocket wheel, the attachment assembly and the vehicle. 
     The leading and trailing frame members of the track system of the present technology define a “split-frame” configuration, with each frame member pivotable about the same pivot cylinder axis, and the suspension assembly connected therebetween. In the context of the present technology, a half track assembly shall be understood to be one of the leading frame member or the trailing frame member, frame member&#39;s wheel-bearing members, their respectively attached wheels and the portions of the endless track that interface between those wheels and a ground surface. 
     The split-frame configuration and optimized movement amplitude of the track system&#39;s movable elements may yield noticeable improvements under certain conditions when a vehicle is operatively attached to one or more track systems and its track assemblies are unevenly loaded. For instance, when operated over an uneven ground surface having irregularities of larger amplitude, such an irregularity may bias a half track assembly to dynamically adapt the position and area of the endless track portion as a function of the vertical and longitudinal dimensions (with respect to the vehicle) of the irregularity thereby imparting movements of a lesser vertical and longitudinal amplitude to its counterpart or to the vehicle via their respective resilient attachments through the support frame. 
     In some situations, the suspension assembly of the track system may assist in dampening the rotation of a biased half track assembly as it approaches the bottomed operative position. Also, the suspension assembly may assist in biasing the rotation of a half track assembly intermediate an operative position and the deployed operative position as the loading conditions are modified. 
     In addition, the track system may provide further advantages when attached to a vehicle operated over an even ground surface. When the track system is loaded according to a given distribution of weight carried by the vehicle, which may also increase and shift (e.g. during harvesting operations), the leading and trailing half track assemblies of the track system move forwardly and rearwardly respectively to adjust the area of the ground-contacting portion of endless track thereby dynamically distributing the load to the ground with an optimized pressure and, under certain conditions, improving the stability of the vehicle by mitigating the risk of the ground yielding under a concentrated load. 
     In some embodiments, the lateral portions are fixedly detachable from the central portion of the attachment assembly, which may facilitate the removal of track assemblies of the track system for maintenance or for replacement with other ground-engaging assemblies such as wheel assemblies. 
     In some embodiments, the receiving portions of the lateral portions of the attachment assembly have a housing for receiving a portion of the sprocket wheel such as a fixed portion of a bearing assembly. This may assist in efficiently distributing the load from the vehicle to the track assembly of the track system to improve the durability and mitigation of vibrations. 
     In some embodiments, a receiving portion of the lateral portion of the attachment assembly has a pad for limiting the upward rotational amplitude of the leading frame member. This movement limitation may assist in defining the bottomed operative position of the track system. 
     In some embodiments, a receiving portion of the lateral portion of the attachment assembly has a pad for limiting the upward rotational amplitude of the trailing frame member. This movement limitation may assist in defining the bottomed operative position of the track system. 
     In some embodiments, the leading attachment arm and the trailing attachment arm are positioned differently with respect to the attachment assembly. The pivot cylinder of the attachment assembly is pivotably received into the bore of the tab of the leading attachment, and the inward-facing tab wall of the leading attachment arm abuts the track assembly abutting wall of the attachment assembly. The pivot cylinder of the attachment assembly is pivotably received into the bore of the tab of the trailing attachment, and the inward-facing tab wall of the trailing attachment arm abuts the outward-facing tab wall of the trailing attachment arm. 
     In some embodiments, the leading attachment arm, the trailing attachment arm, the pivot cylinder and the sprocket wheel are structured and arranged one with respect to the other such that the leading attachment arm tab and the trailing attachment arm tab are positioned outwardly from the sprocket wheel. 
     In some embodiments, the leading attachment arm, the trailing attachment arm, the pivot cylinder and the sprocket wheel are structured and arranged one with respect to the other such that the leading attachment arm tab and the trailing attachment arm tab are positioned bilaterally from the sprocket wheel. 
     In some embodiments, the suspension assembly has a pair of extensible members each having a spring element and a damping element, disposed intermediate a forwardmost attachment tab and a rearwardmost attachment tab. The forwardmost extensible member is pivotably attached to the leading suspension pivot via its forwardmost attachment tab, and to a suspension link via its rearwardmost attachment tab. The rearwardmost extensible member is pivotably attached to the suspension link via its forwardmost attachment tab, and to the trailing suspension tab via its rearwardmost attachment tab. 
     In some embodiments, the suspension assembly is a pneumatic suspension assembly or a hydraulic suspension assembly. 
     In some embodiments, an actuator of the vehicle is operatively connected to the suspension assembly, and capable of adjusting the length, spring properties and damping properties of each extensible element automatically according to vehicle operating conditions (e.g. carried weight, speed, ground surface regularity, etc.) or selectably according to vehicle operator selection based on operating needs (e.g. comfort level, work to be performed, equipment requirements, etc.). This feature may assist in adjusting the operative position and performance of a track assembly of the track system according to operating conditions or operating needs. 
     In some embodiments, each idler wheel and each roller wheel represents an assembly of a pair of concentrically-aligned wheels of a same dimension. 
     According to another aspect of the present technology, there is provided a track system for a vehicle, the vehicle having a chassis and an axle assembly extending laterally outwardly from the chassis suitable for the track system to be rotatably connected thereto. The track system has an attachment assembly mountable to the chassis of the vehicle. The attachment assembly includes an attachment-assembly pivotable connector extending laterally outward from the chassis when the attachment assembly is mounted to the chassis, the attachment assembly pivotable connector defining an attachment-assembly-pivotable connector pivot axis. The track system further has a track assembly including a support frame disposed laterally outward from the attachment assembly when the attachment assembly is mounted to the vehicle, the support frame including a leading frame assembly and a trailing frame assembly. Each frame assembly includes a frame member having a frame-attachment pivotable connector connectable to the attachment-assembly pivotable connector, and a frame-suspension pivotable connector defining a frame-suspension-pivotable-connector pivot axis. Each frame assembly further has at least one wheel-load-bearing connector, and at least one wheel being at least indirectly connected to the frame member via the at least one wheel-load-bearing-connector. The track system further has a sprocket wheel rotatable about a sprocket axis and connectable to the axle assembly of the vehicle, an endless track extending around the sprocket wheel and the at least one idler wheel of the leading frame assembly and the at least one idler wheel of the trailing frame assembly. The track system further has a suspension assembly having a forward suspension pivotable connector pivotably attached to the leading frame-suspension pivotable connector, a rearward suspension pivotable connector pivotably attached to the trailing frame-suspension pivotable connector, and a suspension member operatively connected to the forward suspension pivotable connector and to the rearward suspension pivotable connector. 
     In some embodiments, the suspension member has a forward member pivotable connector pivotably connected to the forward suspension pivotable connector, and a rearward member pivotable connector pivotably connected to the rearward suspension pivotable connector. 
     In some embodiments, the suspension member has a spring and a damper. 
     In some embodiments, the attachment assembly is solely connected to the track assembly via the leading frame-attachment pivotable connector and the trailing frame-attachment pivotable connector. 
     In some embodiments, the suspension assembly is solely connected to a remainder of the track assembly via the leading frame-suspension pivotable connector and the trailing frame-suspension pivotable connector. 
     In some embodiments, a load of the vehicle is transmitted to the track assembly via the attachment assembly. 
     In some embodiments, the leading and trailing frame suspension pivotable connectors are disposed outwardly from the sprocket wheel, and the leading and trailing frame-attachment pivotable connectors are disposed inwardly from the sprocket wheel. 
     In some embodiments, the attachment assembly has a plurality of receiving portions adapted for receiving portions of the chassis of the vehicle. 
     In some embodiments, the attachment assembly has an outwardly facing abutment from which the attachment assembly pivotable connector extends laterally outward. 
     In some embodiments, when the pivot axis of the leading frame suspension pivotable connector is in a highest position, the leading frame assembly is in a bottomed position. 
     In some embodiments, when the pivot axis of the trailing frame suspension pivotable connector is in a highest position, the trailing frame assembly is in a bottomed position. 
     In some embodiments, when the leading frame assembly and trailing frame assembly are in a bottomed position, the leading frame-suspension-pivotable-connector pivot axis and the trailing frame-suspension-pivotable-connector pivot axis are at a position that is higher than the position of the attachment-assembly-pivotable connector pivot axis. 
     In some embodiments, the suspension member is a leading suspension member having a forward leading member pivotable connector pivotably connected to the forward suspension pivotable connector, and a rearward leading member pivotable connector pivotably connected to a link, and the suspension assembly further has a trailing suspension member having forward trailing member pivotable connector pivotably connected to the link and a rearward trailing member pivotable connector pivotably connected to the rearward suspension pivotable connector. 
     In some embodiments, each of the leading suspension member and the trailing member has a spring and a damper. 
     In some embodiments, the leading and trailing frame suspension pivotable connectors are disposed inwardly from the sprocket wheel. 
     In some embodiments, the leading and trailing attachment pivotable connectors are disposed inwardly from the sprocket wheel. 
     Embodiments of the present technology each have at least one of the above-mentioned object and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and/or may satisfy other objects not specifically recited herein. 
     Additional and/or alternative features, aspects, and advantages of embodiments of the present technology will become apparent from the following description, the accompanying drawings, and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the present technology, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where: 
         FIG.  1    is a perspective view taken from a rear, top, left side of a track system being an embodiment of the present technology, the left track assembly of the track system being shown without the endless track for clarity. 
         FIG.  2    is a top plan view of the track system of  FIG.  1   . 
         FIG.  3    is a perspective cross-sectional view of the track system of  FIG.  1    taken along cross-section line  3 - 3  of  FIG.  2   . 
         FIG.  4    is a close-up perspective view taken from a rear, top, left side of the attachment assembly of the track system of  FIG.  1   . 
         FIG.  5    is a close-up perspective view taken from a rear, top, left side of the left leading frame member, trailing frame member and suspension assembly of the track system of  FIG.  1   . 
         FIG.  6    is a perspective view taken from a front, top, left side of left and right track assemblies of a track system being an alternative embodiment of the present technology, the left track assembly being shown without the endless track and without the drive interface of the sprocket wheel, for clarity. 
         FIG.  7    is a perspective view taken from a front, top, right side of the left track assembly of  FIG.  6   , the left track assembly being shown without the endless track and without the drive interface of the sprocket wheel, for clarity. 
     
    
    
     DETAILED DESCRIPTION 
     Introduction 
     With reference to  FIGS.  1  to  5   , an embodiment of the present technology, track system  1000 , will be described. In addition, with reference to  FIGS.  6  and  7   , another embodiment of the present technology, track system  2000 , will be described. It is to be expressly understood that the track system  1000  and the track system  2000  are merely embodiments of the present technology. Thus, the description thereof that follows is intended to be only a description of illustrative examples of the present technology. This description is not intended to define the scope or set forth the bounds of the present technology. In some cases, what are believed to be helpful examples of modifications or alternatives to track system  1000  and track system  2000  may also be set forth below. This is done merely as an aid to understanding, and, again, not to define the scope or set forth the bounds of the present technology. These modifications are not an exhaustive list, and, as a person skilled in the art would understand, other modifications are likely possible. Further, where this has not been done (i.e. where no examples of modifications have been set forth), it should not be interpreted that no modifications are possible and/or that what is described is the sole manner of implementing or embodying that element of the present technology. As a person skilled in the art would understand, this is likely not the case. In addition, it is to be understood that the track system  1000  and the track system  2000  may provide in certain aspects a simple embodiment of the present technology, and that where such is the case it has been presented in this manner as an aid to understanding. As persons skilled in the art would understand, various embodiments of the present technology may be of a greater complexity than what is described herein. 
     In the context of the following description, “outwardly” or “outward” means away from a longitudinal centerline  40  ( FIG.  2   ) of the chassis of the vehicle (not shown), and “inwardly” or “inward” means toward the longitudinal centerline  40 . In addition, in the context of the following description, “longitudinally” means in a direction parallel to the longitudinal centerline  40  of the chassis of the vehicle. 
     In the following description and in the accompanying Figures, the track system  1000  ( FIGS.  1  to  5   ) and the track system  2000  ( FIGS.  6  and  7   ) are configured to be attached to a left side of the chassis of the vehicle. The Figures also show other track systems  1001 ,  2001  being another embodiment of the present technology, configured to be connected to a right side of the chassis of the vehicle, adapted as a mirror image of the track systems  1000 ,  2000 . As the mirror images  1001 ,  2001  of track systems  1000 ,  2000  require no further adaptation, they will not be further described herein. 
     Shown track systems  1000 ,  2000  are for use with a vehicle (not shown) having a chassis (not shown) and an axle assembly (not shown) extending laterally outward from the chassis for connecting to shown track systems  1000 ,  2000 . The chassis supports the components of the vehicle, such as the cabin, the engine, the gearbox and other drivetrain components (not shown). In these embodiments, the axle assembly is a drive axle assembly that rotatably connects the vehicle to the track systems  1000 ,  2000  and thereby transmits a driving torque from the engine and gearbox of the vehicle to the track systems  1000 ,  2000 . 
     General Description of the Track System 
     Referring to  FIGS.  1  to  5   , the track system  1000  will be generally described. The track system  1000  includes an attachment assembly  1100  mountable to the chassis of the vehicle. The attachment assembly  1100  includes a central portion  1110 , a lateral portion  1150 , and an attachment-assembly-pivotable connector  1160  ( FIG.  3   ) extending laterally outward from the attachment assembly  1100 . 
     The track system  1000  further includes a support frame  1300  disposed laterally outward from the attachment assembly  1100  ( FIG.  1   ). The support frame  1300  includes a leading frame assembly  1400  and a trailing frame assembly  1600 . 
     The leading frame assembly  1400  includes a leading frame member  1410 , a wheel-bearing member  1450  ( FIG.  4   ), support wheels  1470  and idler wheels  1475 . The leading frame member  1410  is pivotably connected to the attachment assembly  1100 . The wheel-bearing member  1450  is pivotably connected to the leading frame member  1410 . The support wheels  1470  and the idler wheels  1475  are rotatably connected to the wheel-bearing member  1450 . 
     The trailing frame assembly  1600  includes a trailing frame member  1610 , a wheel-bearing member  1650  ( FIG.  4   ), support wheels  1670  and idler wheels  1675 . The trailing frame member  1610  is pivotably connected to the attachment assembly  1100 . The wheel-bearing member  1650  is pivotably connected to the trailing frame member  1610 . The support wheels  1670  and the idler wheels  1675  are rotatably connected to the wheel-bearing member  1650 . 
     The track system  1000  further includes a sprocket wheel  1700  rotatable about a sprocket axis (not shown). The sprocket wheel  1700  has a connecting portion (not shown) suitable to be rotatably connected to the axle assembly of the vehicle. 
     The track system  1000  further includes an endless track  1800  extending around the sprocket wheel  1700 , around the support wheels  1470  and idler wheels  1475  of the leading frame assembly  1400 , and around the support wheels  1670  and idler wheels  1675  of the trailing frame assembly  1600 . The endless track  1800  is drivable by the sprocket wheel  1700 . 
     The track system  1000  further includes a suspension assembly  1900 . The suspension assembly  1900  has a suspension member  1910  (being a shock absorber in this embodiment). The suspension assembly  1900  is pivotably connected to the leading frame member  1410  and to the trailing frame member  1610 , and is outwardly disposed with respect to the sprocket wheel  1700 . 
     Referring to  FIGS.  6  and  7   , the track system  2000  will be generally described. The track system  2000  includes an attachment assembly  2100  mountable to the chassis of the vehicle. The attachment assembly  2100  includes a central portion similar to the central portion  1110  ( FIG.  4   ), a lateral portion similar to the lateral portion  1150  ( FIG.  2   ) and extending outward from the central portion. The lateral portion is detachable from the central portion. The attachment assembly  2100  further includes an attachment-assembly-pivotable connector  2160  which extends outward from the lateral portion. 
     The track system  2000  further includes a support frame  2300  disposed laterally outward from the attachment assembly  2100  ( FIG.  6   ). The support frame  2300  includes a leading frame assembly  2400  and a trailing frame assembly  2600  ( FIG.  7   ). 
     The leading frame assembly  2400  includes a leading frame member  2410 , a wheel-bearing member  2450 , support wheels  2470  and idler wheels  2475 . The leading frame member  2410  is pivotably connected to the attachment assembly  2100  via the attachment-assembly pivotable connector  2160 . The wheel-bearing member  2450  is pivotably connected to the leading frame member  2410 . The wheels  2470  and the idler wheels  2475  are rotatably connected to the wheel-bearing member  2450 . 
     The trailing frame assembly  2600  includes a trailing frame member  2610 , a wheel-bearing member  2650 , support wheels  2670  and idler wheels  2675 . The trailing frame member  2610  is pivotably connected to the attachment assembly  2100  via the attachment-assembly pivotable connector  2160 . The wheel-bearing member  2650  is pivotably connected to the trailing frame member  2610 . The wheels  2670  and the idler wheels  2675  are rotatably connected to the wheel-bearing member  2650 . 
     The track system  2000  further includes a sprocket wheel  2700  rotatable about a sprocket axis (not shown), and further includes a connecting interface suitable to be rotatably connected to the axle assembly of the vehicle  10 . 
     The track system  2000  further includes an endless track  2800  extending around the sprocket wheel  2700 , around the wheels  2470  and idler wheels  2475  of the leading frame assembly  2400 , and around the wheels  2670  and idler wheels  2675  of the trailing frame assembly  2600 . The endless track  2800  is drivable by the sprocket wheel  2700 . 
     The track system  2000  further includes a suspension assembly  2900 . The suspension assembly  2900  has two suspension members  2910 ,  2920  (being shock absorbers in this embodiment) pivotably interconnected by a link  2940 . The suspension member  2910  is pivotably connected to the leading frame member  2410 . The suspension member  2920  is pivotably connected to the trailing frame member  2610 . The suspension assembly  2900  is inwardly disposed with respect to the sprocket wheel  2700 . 
     Attachment Assembly 
     Referring back to  FIGS.  2  and  4   , the central portion  1100  defines vertical receiving portions  1120  and a horizontal receiving portion  1122  for receiving portions of the chassis of the vehicle. The central portion  1100  includes a front portion  1112  and a rear portion  1114  on which are disposed fastener interfaces  1116 ,  1117  for fastening the attachment assembly  1100  to the chassis of the vehicle. Fastener interface  1117  receives fasteners  1118  such as bolts ( FIG.  4   ). 
     The lateral portion  1150  includes an outwardly-facing abutment  1152  and an attachment-assembly-pivotable connector  1160  ( FIG.  4   ) defining an attachment-assembly-pivotable connector axis  1162  (shown in  FIG.  2    overlapping cross-section line  3 - 3 ). The attachment-assembly-pivotable connector  1160  extends outward from the abutment  1152 . The lateral portion  1150  further includes a track assembly receiving portion  1180 , extending outwardly from the abutment  1152 . As best shown in  FIG.  3   , the track assembly receiving portion  1150  has a proximal arm  1182 , a brace  1184  for receiving an axle casing of the vehicle, a distal arm  1186  and a pad  1188 . In some embodiments, the brace  1184  is configured to non-engagingly support the sprocket wheel  1700  in order to reduce the vertical load transmitted to the axle assembly of the vehicle without undesirably limiting the rotation of the sprocket wheel  1700 . In some embodiments, the pad  1188  is adapted to limit the pivoting movement of the leading frame member  1410  when a portion of the leading frame member  1410  makes contact with the pad  1188 , thereby defining the bottomed position of the leading frame member  1410 . In some embodiments, the attachment assembly  1100  does not include a track assembly receiving portion  1180 . 
     In the other embodiment of the present technology shown in  FIGS.  6  and  7   , the attachment assembly  2100  of the track system  2000  has a central portion and a lateral portion detachable therefrom via a mounting portion  2190 . The lateral portion has an attachment-assembly-pivotable connector  2160  pivotably connected to leading and trailing frame members  2410 ,  2610  and indirectly connected to the remainder of the track system  2000 . Under certain conditions, the maintenance of the track system  2000  or its substitution by a wheel assembly is facilitated by detaching the lateral portion from the central portion and leaving the central portion mounted to the chassis of the vehicle. 
     Support Frame 
     Referring back to  FIGS.  1  to  5   , the track system  1000  includes the support frame  1300  disposed laterally outward from the attachment assembly  1100 . The support frame  1300  includes the leading frame assembly  1400  and the trailing frame assembly  1600 . 
     The trailing frame assembly  1600  includes a trailing frame member  1610  having an arm-like structure, best seen in  FIG.  2   . The trailing frame member  1610  has a trailing frame-attachment pivotable connector  1620  ( FIG.  3   ) that abuts the abutment  1152  and is pivotably connected to the attachment-assembly-pivotable connector  1160 . The trailing frame member  1610  pivots about the attachment-assembly-pivotable connector pivot axis  1162 . The trailing frame member  1610  further has the wheel-bearing member  1650  to which are rotatably connected the support wheels  1670  and idler wheels  1675 , the idler wheels  1675  being the trailing wheels of the track system  1000 . The support wheels  1670  are mounted in a tandem configuration via a tandem assembly  1680  ( FIG.  4   ) pivotably connected to the wheel-bearing member  1650 . The trailing frame member  1610  further has a trailing frame-suspension pivotable connector  1640  that defines a trailing frame-suspension pivotable connector axis  1645  ( FIG.  5   ). 
     Referring to  FIGS.  1 ,  2  and  4   , the leading frame assembly  1400  includes the leading frame member  1410  having an arm-like structure, as best seen in  FIG.  4   . The leading frame member  1410  has the leading frame-attachment pivotable connector  1420  that abuts the trailing frame-attachment pivotable connector  1620 . The leading frame-attachment pivotable connector  1420  is disposed outward from the trailing frame-attachment pivotable connector  1620 . The leading frame member  1410  is pivotably connected to the attachment-assembly-pivotable connector  1160 . The leading frame member  1410  further has the wheel-bearing member  1450  to which are rotatably connected the support wheels  1470  and the idler wheels  1475 , the idler wheels  1475  being the leading wheels of the track system  1000 . Referring to  FIG.  5   , the leading frame member  1410  further has a leading frame-suspension pivotable connector  1440  that defines a leading frame-suspension pivotable connector axis  1445 . 
     The leading and trailing frame-attachment pivotable connectors  1420 ,  1620  are disposed inwardly with respect to the sprocket wheel  1700 . The leading and trailing frame-suspension pivotable connectors  1440 ,  1640  are disposed outwardly with respect to the sprocket wheel  1700 . 
     Sprocket Wheel 
     Referring to  FIGS.  1  to  7   , the sprocket wheel  1700  includes an axle assembly interface (not shown) defining a sprocket axis  1720  ( FIG.  3   ). The sprocket wheel  1700  has teeth  1710 . The axle assembly interface of the sprocket wheel  1700  is connectable to the axle assembly of the vehicle for rotating the sprocket wheel  1700  about the sprocket axis  1720 . When the track system  1000  is drivingly connected to the drive axle assembly of the vehicle, the sprocket wheel  1700  drivingly rotates about the sprocket axis  1720  and the teeth  1710  drivingly engage the endless track  1800 . In some embodiments of the present technology, the sprocket wheel  1700  further includes a support interface (not shown) adapted to be received in a track assembly receiving portion  1150  of the attachment assembly  1100 . 
     Endless Track 
     Referring to  FIGS.  1 ,  2 ,  3 , and  5   , the endless track  1800  is an endless polymeric track. For clarity, the endless track  1800  is shown on the mirror image  1001  of the track system  1000  configured to be connected on the right side of the chassis of the vehicle. The endless track  1800  has an inner surface  1810  engaging the leading support wheels  1470  and leading idler wheels  1475 , the trailing support wheels  1670  and the trailing idler wheels  1675  and the sprocket wheel  1700 . The inner surface has lugs  1820  ( FIG.  1   ) disposed on a central portion of the inner surface  1810  for engaging the teeth  1710  of the sprocket wheel  1700 . The endless track  1800  also has an outer surface  1840  with a tread (not shown) configured for ground engagement. The tread can be varied according to the type of vehicle on which the track system  1000 ,  1001  is to be used with and/or the type of ground surface on which the vehicle will be driven. The endless track  1800  further has internal and external walls  1850 ,  1860 , disposed inwardly from and outwardly of the leading and trailing frame assemblies  1410 ,  1610  and the sprocket wheel  1700 . It is contemplated that within the scope of the present technology, the endless track  1800  may be constructed of a wide variety of materials and structures including metallic components known in track systems. The specific properties and materials of the endless track  1800  are not central to the present technology and will not be described in detail. 
     Suspension Assembly 
     Referring to  FIGS.  1 ,  2 ,  4  and  5   , the suspension assembly  1900  includes a suspension member  1910  being a shock absorber and rotatably connected to the frame-suspension pivotable connectors  1440 ,  1640  via a forward suspension pivotable connector  1911  and a rearward suspension pivotable connector  1912  ( FIG.  5   ). The suspension assembly  1900  and the leading and trailing-frame-suspension pivotable connectors  1440 ,  1640  are disposed inwardly from the endless track external wall  1860 , outwardly of the sprocket wheel  1700  and upwardly from the leading support wheels  1470  and trailing support wheels  1670 . The forward and rearward suspension pivotable connectors  1911 ,  1912  are disposed forward and rearward respectively and above the attachment-assembly-pivotable connector pivot axis  1162  ( FIG.  5   ). 
     The arrangement of the suspension assembly  1900  as described allows the damping of the movements of the leading and trailing frame assemblies  1400 ,  1600  and still allows adequate amplitude of movement thereof.  FIG.  1    shows the track system  1000  positioned as when attached to a vehicle disposed on a leveled ground surface, with the suspension assembly  1900  in an operative position. The suspension member  1910 , in this embodiment being a damper, is shown having a length intermediate its shortest length (compressed, bottomed) and longest length (extended, deployed), the length and shock absorption capacity being determined according to the stroke length and mechanical properties (e.g. damping ratio, spring constant) of the suspension member  1910  as a function of the load borne thereby. 
     In the embodiment of the present technology shown in  FIGS.  6  and  7   , the suspension assembly  2900  of the track system  2000  has leading and trailing suspension members  2910 ,  2920  and a link  2940  pivotably interconnected thereto. The leading suspension member  2910  is pivotably connected to the leading-frame-suspension pivotable connector  2440  and to the link  2940  via the forward and rearward leading suspension pivotable connectors  2911 ,  2912 . The trailing suspension member  2920  is pivotably connected to the link  2940  and to the trailing-frame-suspension pivotable connector  2640  via the forward and rearward trailing suspension pivotable connectors  2921 ,  2922 . As seen on  FIG.  6   , the suspension assembly  2900  and the leading and trailing frame-suspension pivotable connectors  2440 ,  2640  are disposed outwardly from the endless track internal wall  2850  (shown on the right side mirror image), inwardly from the sprocket wheel  2700  and upwardly from the leading and trailing support wheels  2470 ,  2670 . The forward leading and the rearward trailing suspension pivotable connectors  2911 ,  2922  extend above the attachment-assembly-pivotable connector  2160  and are disposed forward and rearward therefrom respectively. The leading and trailing suspension members  2910 ,  2920  are disposed forward and rearward respectively of the sprocket axis, and the link  2940  is disposed above thereof. 
     In some embodiments, the length and shock absorption capacity of the suspension members  1910 ,  2910  are remotely adjustable by the operator of the vehicle via an actuator thereof. In some embodiments, the suspension members  1910 ,  2910  are replaced by other adequate shock absorbing arrangements known in the art. 
     Modifications and improvements to the above-described embodiments of the present technology may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting. The scope of the present technology is therefore intended to be limited solely by the scope of the appended claims.