Patent Description:
Certain vehicles, such as, for example, agricultural vehicles (e.g., harvesters, combines, tractors, etc.) and construction vehicles (e.g., bulldozers, front-end loaders, etc.), are used to perform work on ground surfaces that are soft, slippery and/or uneven (e.g., soil, mud, sand, ice, snow, etc.).

Conventionally, such vehicles have had large wheels with tires on them to move the vehicle along the ground surface. Under certain conditions, such tires may have poor traction on some kinds of ground surfaces and, as these vehicles are generally heavy, the tires may compact the ground surface in an undesirable way owing to the weight of the vehicle. 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.

In order to reduce the aforementioned drawbacks, to increase traction and to distribute the weight of the vehicle over a larger area on the ground surface, track systems were developed to be used in place of at least some of the wheels and tires on the vehicles. For example, under certain conditions, track systems enable agricultural vehicles to be used in wet field conditions as opposed to its wheeled counterpart.

The use of track systems in place of wheels and tires, however, does present some inconveniences. One of the drawbacks of conventional track systems is that, under certain conditions, the endless track can be in ground contact with an uneven load distribution across its ground contacting segment, i.e. the portion of the endless track contacting the ground. As such, since the load is not evenly distributed, areas of the ground contacting segment create high and low pressure spots on the ground surface. The high pressure spots cause undesirable soil compaction at different depth levels. In addition, the uneven distribution of the load can lead to premature wear of some components of the track system. One factor that leads to the uneven distribution of the load across the ground contacting segment of an endless track under certain conditions is that the structural components of the track system do not always allow the endless track to conform evenly to the ground surface like a tire filled with gas (air or nitrogen) does.

<CIT> concerns a suspension device for a tracked vehicle having at least one pair of track assemblies, each track assembly including a track support beam, at least one drive wheel, a plurality of support wheels and an endless track, wherein said at least one drive wheel and said plurality of support wheels are rotatably secured to said track support beam.

<CIT> concerns a track suspension comprising a drive wheel, a yoke plate carrier, a front wishbone member, a rear wishbone member, a front rocker assembly, a rear rocker assembly, a front suspension spring assembly and a rear suspension spring assembly.

<CIT> concerns a work vehicle including left and right track assemblies, each track assembly having a main frame, a pivot member, a pivot shaft coupled to the pivot member, and an actuator coupled between the pivot shaft and the main frame.

As such, there remains that there is a need for continued improvement in the design and configuration of track systems so that soil compaction issues and wear of some components of the track system be further reduced.

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 system at least in some instances as compared with some of the prior art.

In accordance with one aspect of the present technology, there is provided a track system for use with a vehicle having a chassis, the track system including an attachment assembly connectable to the chassis of the vehicle. The attachment assembly includes a first pivot extending vertically and defining a yaw pivot axis of the track system, and a second pivot extending laterally and defining a pitch pivot axis of the track system. The track system further includes a frame assembly disposed laterally outwardly from the attachment assembly and connected to the attachment assembly, the frame assembly including at least one wheel bearing frame member, at least one actuator connected between the attachment assembly and the frame assembly for pivoting the frame assembly about the yaw pivot axis, a leading idler wheel assembly at least indirectly connected to the at least one wheel-bearing frame member, a trailing idler wheel assembly at least indirectly connected to the at least one wheel-bearing frame member, at least one support wheel assembly at least indirectly connected to the at least one wheel-bearing frame member and disposed between the leading idler wheel assembly and the trailing idler wheel assembly, and an endless track extending around the leading idler wheel assembly, the trailing idler wheel assembly, and the at least one support wheel assembly.

In some embodiments, the attachment assembly further includes a third pivot extending longitudinally and defining a roll pivot axis of the track system, the frame assembly being further pivotable about the roll pivot axis upon operation of the at least one actuator.

In some embodiments, the attachment assembly includes a yoke, a pivot arm pivotally connected to the yoke by the third pivot and pivoting about the roll pivot axis, a plate connected to the pivot arm by the first pivot and pivoting about the yaw pivot axis, the second pivot projecting from the plate, and the plate being pivotable about the roll and yaw pivot axes relative to the yoke.

In some embodiments, the at least one actuator is a first, second and third actuators, the first actuator being operable for pivoting the frame assembly about the roll pivot axis, and the second and third actuators being operable for pivoting the frame assembly about the yaw pivot axis.

In some embodiments, the second actuator is a leading tracking actuator located forward of the second pivot, and the third actuator is a trailing tracking actuator located rearward of the second pivot.

In some embodiments, the attachment assembly includes an axle casing including the first pivot, the first pivot being defined by a cylindrical projection, and a base defining a cylindrical aperture dimensioned for receiving the cylindrical projection.

In some embodiments, the base has at least one tab, and the second pivot extends through the at least one tab of the base.

In some embodiments, the frame assembly is a multi-member frame assembly including a leading frame member pivotably connected to the attachment assembly via the second pivot for pivoting about the pitch pivot axis, a trailing frame member pivotably connected to the attachment assembly via the second pivot for pivoting about the pitch pivot axis, the trailing frame member pivoting independently from the leading frame member. The at least one wheel-bearing frame member is a leading wheel-bearing frame member and a trailing wheel-bearing frame member, the leading wheel-bearing frame member being at least indirectly pivotably connected to the leading frame member, the trailing wheel-bearing frame member being at least indirectly pivotably connected to the trailing frame member, and the track system further includes a leading damper interconnecting the axle casing and leading frame member, and a trailing damper interconnecting the axle casing and the trailing frame member.

In some embodiments, the endless track has an amount of ground contact area that increases as a load borne by the track system increases.

In some embodiments, a load supported by the trailing wheel-bearing frame member is greater than a load supported by the leading wheel-bearing frame member.

In some embodiments, the vehicle has a drive shaft extending laterally outwardly of the chassis, and the track system further has a sprocket wheel at least indirectly connected to the drive shaft for driving the endless track.

In some embodiments, the track system further includes at least one monitoring sensor for determining, at least indirectly, at least one of a state of the track system and a ground surface condition, and a track system controller communicating with the at least one monitoring sensor for receiving a first signal indicative of the at least one of the state of the track system and the ground surface condition, the track system controller being configured to connect to and to control the operation of the at least one actuator based on the at least one of the state of the track system and the ground surface condition.

In some embodiments, the at least one monitoring sensor includes at least one of a load sensor, temperature sensor, accelerometer, strain gauge, fluid property sensor, inclinometer, actuator assembly position sensor, geographical location sensor, hygrometer, penetrometer, sonar device, ultrasonic device, microwave-based device, radar device, and lidar device.

In some embodiments, the track system controller controls the operation of the at least one actuator in response to a second signal received from a manual override, a master control unit mounted to the vehicle, a remote processing unit, or a remote master control unit.

In some embodiments, the track system controller controls the operation of the at least one actuator in accordance with a predetermined objective.

In some embodiments, the predetermined objective is distributing a load supported by the track system across a surface of a ground engaging segment of the endless track for at least one of reducing soil compaction and improving traction of the endless track.

In some embodiments, the track system further includes at least one idler actuator for adjusting the pivotal positioning of at least one of the leading and trailing idler wheel assemblies relative to the frame assembly including raising the at least one of the leading and trailing idler wheel assemblies to reduce an amount of endless track in flat ground contact and lowering the at least one of the leading and trailing idler wheel assemblies to increase the amount of endless track in flat ground contact, and the track system controller is further configured to connect to and to control the operation of the at least one idler actuator based on the at least one of the state of the track system and the ground surface condition.

There is also provided a vehicle including first and second track systems as described above, and the track system controller of the first track system is at least indirectly connected to the track system controller of the second track system, and the track system controller of the first track system controls the operation of the at least one actuator of the first track system based on at least one of the state of the second track system and the ground surface condition determined by the at least one monitoring sensor of the second track system.

In accordance with another aspect of the present technology, there is provided a track system for use with a vehicle having a chassis, the track system including an attachment assembly connectable to the chassis of the vehicle, the attachment assembly including a pivot extending vertically and defining a yaw pivot axis of the track system, a frame assembly disposed laterally outwardly from the attachment assembly and connected to the attachment assembly, the frame assembly including at least one wheel-bearing frame member, at least one selectively extendible and retractable tie-rod assembly connected between the attachment assembly and the frame assembly for pivoting the frame assembly about the yaw pivot axis, a leading idler wheel assembly at least indirectly connected to the at least one wheel-bearing frame member, a trailing idler wheel assembly at least indirectly connected to the at least one wheel-bearing frame member, at least one support wheel assembly at least indirectly connected to the at least one wheel-bearing frame member and disposed between the leading idler wheel assembly and the trailing idler wheel assembly, and an endless track extending around the leading idler wheel assembly, the trailing idler wheel assembly, and the at least one support wheel assembly.

In some embodiments, the attachment assembly includes an axle casing including the pivot, the pivot being defined by a cylindrical projection, and a base defining a cylindrical aperture dimensioned for receiving the cylindrical projection.

Should there be any difference in the definitions of term in this application and the definition of these terms in any document included herein by reference, the terms as defined in the present application take precedence.

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, and the accompanying drawings.

With reference to <FIG>, a first embodiment of the present technology, track system <NUM>, is illustrated. It is to be expressly understood that the track system <NUM> is merely an embodiment 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 <NUM> may also be set forth below. 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 <NUM> 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.

Referring to <FIG>, the track system <NUM> is for use with a vehicle <NUM> having a chassis <NUM> and a drive shaft <NUM> extending laterally outwardly from the chassis <NUM> for driving the track system <NUM> (the vehicle <NUM>, the chassis <NUM> and the drive shaft <NUM> are schematically shown in <FIG>). The chassis <NUM> supports the components of the vehicle <NUM>, such as the cabin, the engine, the gearbox and other drivetrain components (not shown). In this embodiment, the drive shaft <NUM> is the drivetrain component that transmits the driving force from the engine and gearbox of the vehicle <NUM> to the track system <NUM>, i.e. the drive shaft <NUM> is the output shaft of the gearbox.

In the context of the following description, "outwardly" or "outward" means away from a longitudinal center plane <NUM> of the chassis <NUM> of the vehicle <NUM>, and "inwardly" or "inward" means toward the longitudinal center plane <NUM>. In addition, in the context of the following description, "longitudinally" means in a direction parallel to the longitudinal center plane <NUM> of the chassis <NUM> of the vehicle <NUM> in a plane parallel to flat level ground, "laterally" means in a direction perpendicular to the longitudinal center plane <NUM> in a plane parallel to flat level ground, and "generally vertically" means in a direction contained in the longitudinal center plane <NUM> along a height direction of the track system <NUM> generally perpendicular to flat level ground. Note that in the Figures, a "+" symbol is used to indicate an axis of rotation. In the context of the present technology, the term "axis" may be used to indicate an axis of rotation, or the term may refer to a "pivot joint" that includes all the necessary structure (bearing structures, pins, axles and other components) to permit a structure to pivot about such axis, as the case may be. Moreover, the direction of forward travel of the track system <NUM> is indicated by an arrow <NUM> in the accompanying Figures. In the present description, the "leading" components are identified with a "l" added to their reference numeral (i.e. components towards the front of the vehicle <NUM> defined consistently with the vehicle's forward direction of travel <NUM>), and the "trailing" components are identified with a "t" added to their reference numeral (i.e. components towards the rear of the vehicle <NUM> defined consistently with the vehicle's forward direction of travel <NUM>). In the following description and accompanying <FIG>, the track system <NUM> is configured to be attached to a left side of the chassis <NUM> of the vehicle <NUM>. A track system <NUM>' (<FIG>), being another embodiment of the present technology and configured to be connected to a right side of the chassis <NUM> of the vehicle <NUM>, is a mirror image of the track system <NUM> with the necessary adaptations, and the components of the track system <NUM>' are identified with a "'" added to their reference numeral. That embodiment will not be further described herein.

Referring to <FIG>, the track systems <NUM>, <NUM> will be generally described. The track systems <NUM>, <NUM>, although being two different embodiments of the present technology, have many similar features and will thus be described collectively. As such, the description made in reference to the track system <NUM> or the track system <NUM> is interchangeable, unless mentioned otherwise.

Referring to <FIG> and <FIG>, the track systems <NUM>, <NUM> include an axle casing <NUM> operatively connectable to the drive shaft <NUM> of the vehicle <NUM>. The axle casing <NUM> includes a pivot <NUM> defined by a cylindrical projection <NUM>, which projects generally vertically from a bottom face of the axle casing <NUM> (best seen in <FIG>). The projection <NUM> defines a yaw pivot axis <NUM> of the track systems <NUM>, <NUM>. A base <NUM> is pivotably connected to the axle casing <NUM> about the yaw pivot axis <NUM>. The base <NUM> has a cylindrical aperture <NUM> dimensioned for receiving the cylindrical projection <NUM>. The base <NUM> is located below the axle casing <NUM>. A pivot <NUM> extends in tabs <NUM> of the base <NUM>. The pivot <NUM> extends laterally. The pivot <NUM> defines a pitch pivot axis <NUM> of the track systems <NUM>, <NUM>.

Referring back to <FIG>, the track systems <NUM>, <NUM> further include a frame assembly <NUM> located below the axle casing <NUM>. A portion of the frame assembly <NUM> extends between the tabs <NUM> of the base <NUM> (as best seen in <FIG> and <FIG>), and is pivotably connected to the base <NUM> via the pivot <NUM>. The frame assembly <NUM> is a multi-member frame assembly, and includes a leading frame member <NUM> pivotably connected to the base <NUM> via the pivot <NUM> for pivoting about the pitch pivot axis <NUM>, and a trailing frame member 210t also pivotably connected to the base <NUM> via the pivot <NUM> for pivoting about the pitch pivot axis <NUM> independently from the leading frame member <NUM>. In other embodiments, the frame assembly <NUM> could be formed of a single frame member connected to the base <NUM> via the pivot <NUM> and pivoting about the pitch pivot axis <NUM>.

The multi-member frame assembly <NUM> also includes a leading wheel-bearing frame member <NUM>l pivotably connected to the leading frame member <NUM>, and a trailing wheel-bearing frame member 230t pivotably connected to the trailing frame member 210t. In other embodiments, the track systems <NUM>, <NUM> could have only one wheel-bearing frame member, which could be the same component as the frame assembly <NUM>. Tandem assemblies <NUM>l, <NUM>t are pivotably connected to the leading and trailing wheel-bearing frame members <NUM>l, <NUM>t about axes <NUM>, <NUM>t (<FIG>) via longitudinally extending bogie members <NUM>l, 260t (<FIG> and <FIG>). The track systems <NUM>, <NUM> further include a leading damper <NUM>l (in this embodiment a shock absorber, but could be a coil spring, an air spring, an hydropneumatic spring or the like) interconnecting the axle casing <NUM> and the leading frame member <NUM>l, and a trailing damper <NUM>t interconnecting the axle casing <NUM> and the trailing frame member 210t. As such, the pivotal motion of the leading frame member <NUM>l relative to the axle casing <NUM> is dampened by the leading damper <NUM>l, and the pivotal motion of the trailing frame member 210t relative to the axle casing <NUM> is dampened by the trailing damper 300t. The leading and trailing dampers <NUM>l, <NUM>t are operatively connected to the axle casing <NUM> and their corresponding frame member <NUM>l, <NUM>t using spherical bushings. As each frame member <NUM>l, <NUM>t has a dedicated damper (i.e. dampers <NUM>l, 300t), the absorption of energy caused by the track systems <NUM>, <NUM> travelling on uneven ground surface is improved compared to conventional track systems, and thus shocks and vibrations transferred from the ground to the vehicle <NUM> are attenuated in some conditions. As a result, wear of components is reduced and the comfort that a user of the vehicle <NUM> experiences is improved compared to conventional track systems.

When the track systems <NUM>, <NUM> support the weight of the vehicle <NUM>, the dampers <NUM>l, <NUM>t are deformed (i.e. compressed). Under certain conditions, vibrations that are caused by the ground surface on which the track systems <NUM>, <NUM> travel, and that are transferred to the leading and trailing frame members <NUM>l, <NUM>t are dampened by the dampers <NUM>l, 300t. In some embodiments, the dampers <NUM>l, <NUM>t have variable damping characteristics as described in commonly owned International Patent Application No. <CIT>, entitled "Progressive Damping System for a Track System" and published as <CIT>. The content of this application is incorporated herein by reference in its entirety.

A leading idler wheel assembly <NUM>l is rotatably connected to the leading wheel-bearing frame member <NUM>l, and a trailing idler wheel assembly <NUM>t is rotatably connected to the trailing wheel-bearing frame member <NUM>t. A plurality of support wheel assemblies <NUM>a, <NUM>b, <NUM>c, <NUM>d are disposed intermediate the leading idler wheel assembly <NUM>l and the trailing idler wheel assembly <NUM>t. The support wheel assemblies <NUM>a, <NUM>b are rotatably connected to the bogie member <NUM>l, and the support wheel assemblies 410c, 410d are rotatably connected to the bogie member <NUM>t. In other embodiments, the track systems <NUM>, <NUM> have only one of the leading and trailing idler wheel assemblies <NUM>, 400t. In yet other embodiments, the amount of support wheel assemblies could be less or more than four, as shown in the present embodiments.

Referring to <FIG>, the track systems <NUM>, <NUM> further include a gearbox <NUM> (schematically shown in <FIG>) operatively connected to the drive shaft <NUM> of the vehicle <NUM>. The gearbox <NUM> is operatively connected to the axle casing <NUM>. The track systems <NUM>, <NUM> further include a sprocket wheel <NUM> operatively connected to the axle casing <NUM>. As such, the driving force is transferred from the drive shaft <NUM> to the sprocket wheel <NUM> via the gearbox <NUM> and the axle casing <NUM>. In other embodiments, the gearbox <NUM> could be omitted and the drive shaft <NUM> could be directly operatively connected to the sprocket wheel <NUM> and extending in the axle casing <NUM>.

The track systems <NUM>, <NUM> further include an endless track <NUM> extending around the sprocket wheel <NUM>, the leading idler wheel assembly <NUM>, the trailing idler wheel assembly <NUM>t, and the plurality of support wheel assemblies <NUM>a, 410b, <NUM>c, <NUM>d. The endless track <NUM> is drivable by the sprocket wheel <NUM>.

Referring to <FIG>, the endless track <NUM> is an endless polymeric track. The endless track <NUM> has an inner surface <NUM> engaging the leading idler wheel assembly <NUM>l, the trailing idler wheel assembly <NUM>t, and the plurality of support wheel assemblies <NUM>a, 410b, <NUM>c, <NUM>d. Lugs <NUM> (<FIG>) are disposed on a central portion of the inner surface <NUM> and are engageable by the sprocket wheel <NUM>. As such, the track systems <NUM>, <NUM> are "positive drive" track systems. Friction drive track systems are also contemplated as being an alternative to the present embodiments. Moreover, hybrid drive track systems (i.e. the sprocket wheel <NUM> drives the endless track <NUM> via friction and driving engagement of lugs <NUM>) are also contemplated. The idler and support wheel assemblies <NUM>, 400t, <NUM>a, 410b, <NUM>c, <NUM>d have laterally spaced-apart wheels engaging the inner surface <NUM> of the endless track <NUM> on either side of the lugs <NUM>. The endless track <NUM> also has an outer surface <NUM> with a tread <NUM> (<FIG>) selected for ground engagement. The tread <NUM> varies in different embodiments according to the type of vehicle on which the track systems <NUM>, <NUM> are to be used with and/or the type of ground surface on which the vehicle is destined to travel. It is contemplated that within the scope of the present technology, the endless track <NUM> may be constructed of a wide variety of materials and structures including metallic components known in track systems.

Referring to <FIG>, the endless track <NUM> has a leading segment <NUM>, a ground engaging segment <NUM> and a trailing segment <NUM>. The generally triangular shape of the track systems <NUM>, <NUM> causes the endless track <NUM> to have the segments <NUM>, <NUM>, <NUM>, but as other configurations of the track systems <NUM>, <NUM> are contemplated, the endless track <NUM> could have more or less segments in other embodiments. Referring to <FIG> and as will be described below, the pivotal positioning of the leading idler wheel assembly <NUM>l relative to the leading frame member <NUM>l and the pivotal positioning of the trailing idler wheel assembly 400t relative to the trailing frame member <NUM>t varies by raising or lowering the leading wheel-bearing frame member <NUM>l and the trailing wheel-bearing frame member 230t respectively. When the leading wheel-bearing frame member <NUM>l is raised (<FIG>), the ground engaging segment <NUM> includes a leading ground-engaging segment <NUM>l that extends above ground when the endless track <NUM> is disposed on flat level ground. It is contemplated that, in certain situations such as when the track systems <NUM>, <NUM> travels on soft ground, the ground-engaging segment <NUM>l could engage the ground surface. The leading ground-engaging segment <NUM>l extends below the leading idler wheel assembly <NUM>l. When the trailing wheel-bearing frame member 230t is raised (<FIG>), the ground engaging segment <NUM> further includes a trailing ground engaging segment <NUM>t that extends above ground when the endless track <NUM> is disposed on flat level ground. It is also contemplated that, in certain situations such as when the track systems <NUM>, <NUM> travel on soft ground, the ground-engaging segment <NUM>t could engage the ground surface. The trailing ground engaging segment 622t extends below the trailing idler wheel assembly <NUM>t. Referring to <FIG>, when the leading wheel-bearing frame member <NUM>l and the trailing wheel-bearing frame member <NUM>t are raised, the endless track <NUM> has the leading ground-engaging segment <NUM>l and the trailing ground engaging segment <NUM>t extending above ground. In this configuration, the ground engaging segment <NUM> (i.e. the portion of the endless track <NUM> that engages the ground surface when the endless track <NUM> is disposed on flat level ground) is shorter compared to the ground engaging segment <NUM> of the configurations shown in <FIG>.

As will be described in more details below, the yaw and pitch pivot axes <NUM>, <NUM> permit degrees of freedom of the track systems <NUM>, <NUM> relative to the chassis <NUM> of the vehicle <NUM> that can assist the endless track <NUM> to better conform to the ground surface on which it travels and assist in preserving integrity of the soil as the track systems <NUM>, <NUM> travel thereon.

Referring to <FIG>, a leading tie rod assembly <NUM>l is pivotably connected to the base <NUM> and to the chassis <NUM> of the vehicle <NUM> (the connection to the chassis <NUM> of the vehicle <NUM> is schematically shown in <FIG> by a dashed line). A trailing tie rod assembly <NUM>t is pivotably connected to the base <NUM> and to the chassis <NUM> of the vehicle <NUM> (the connection to the chassis <NUM> of the vehicle <NUM> is schematically shown in <FIG> by a dashed line). Similar to the dampers <NUM>l, <NUM>t, the tie rod assemblies <NUM>l, <NUM>t include spherical bushing at each end thereof. The leading and trailing tie rod assemblies <NUM>, 150t are thus longitudinally offset of the yaw pivot axis <NUM> (shown as a dashed line in <FIG> and <FIG>).

By selectively extending and retracting the tie rod assemblies, <NUM>, 150t, the tracking angle γ of the track systems <NUM>, <NUM> can be adjusted. Referring to <FIG>, retracting the leading tie rod assembly <NUM> and extending the trailing tie rod assembly <NUM>t pivots the base <NUM> relative to the chassis <NUM> (schematically shown in <FIG>) and the axle casing <NUM> about the yaw pivot axis <NUM>, and thus pivoting the leading idler wheel assembly <NUM>l towards the center plane <NUM> of the chassis <NUM> and the trailing idler wheel assembly <NUM>t away from the center plane <NUM> of the chassis <NUM>. This configuration corresponds to a toe-in angle of -γ. Conversely and as seen in <FIG>, extending the leading tie rod assembly <NUM> and retracting the trailing tie rod assembly <NUM>t pivots the base <NUM> relative to the chassis <NUM> (schematically shown in <FIG>) and the axle casing <NUM> about the yaw pivot axis <NUM>, and thus pivoting the leading idler wheel assembly <NUM>l away from the center plane <NUM> of the chassis <NUM> and the trailing idler wheel assembly <NUM>t towards the center plane <NUM> of the chassis <NUM>. This configuration corresponds to a toe-out angle of γ.

In some embodiments, the tie rod assemblies <NUM>l, <NUM>t can provide for tracking angle adjustment of up to about <NUM> degrees, that is angle γ equals to about <NUM> degrees, but larger or smaller angles γ are contemplated in different embodiments. The degree of freedom in yaw motion about the pivot axis <NUM> permits the track systems <NUM>, <NUM>' (or <NUM> and its mirror image connected on the right side of the vehicle <NUM>) to adjust the tracking angle γ depending on, for example, misalignment of the track systems <NUM>, <NUM>' relative to the chassis <NUM> of the vehicle <NUM>.

In other embodiments, the tie rod assemblies <NUM>, 150t are replaced by actuators, which can include electric, hydraulic or pneumatic linear actuators which can be actively controlled for dynamically adjusting the tracking angle γ. In other embodiments, the actuator is a stepper motor operatively connected between the axle casing <NUM> and the base <NUM> which provides rotational motion therebetween about the yaw pivot axis <NUM>. In such embodiments, the adjustment of the tracking angle γ can depend on, for example, temperature of certain portions of the endless track <NUM>, ground surface conditions and the load of the vehicle <NUM>. As such, premature wear of the endless track <NUM> and of other components of the track system <NUM> could be reduced compared to conventional track systems. Moreover, adjustment of the tracking angle γ can also assist in preserving the integrity of the soil on which the track systems <NUM>, <NUM> travel, under certain conditions.

In embodiments where tie rod assemblies <NUM>l, <NUM>t are replaced by actuators and the track system <NUM> is steerable, for example when operatively connected to a steerable component of the chassis <NUM>, the actuators could be operatively connected to the steering system of the vehicle <NUM> so as to provide better steering control under some circumstances.

Referring back to <FIG> and <FIG>, the leading and trailing frame members <NUM>l, <NUM>t will be described. The leading and trailing frame members <NUM>l, <NUM>t are pivotably connected to and supported by the pivot <NUM>. In order to facilitate the pivoting of the leading and trailing frame members <NUM>, 210t on the pivot <NUM>, bearings (not shown) are disposed between the pivot <NUM> and each frame member <NUM>, 210t. In some embodiments, bushings or tapper rollers could be used in place of bearings. In the present embodiments, the leading and trailing frame members <NUM>l, <NUM>t have apertures defined by loops <NUM>l, <NUM>t. The pivot <NUM> extends through the apertures of the loops <NUM>l, 214t similar to a pin in a hinge assembly, and provides for a pivoting of the leading and trailing frame members <NUM>l, <NUM>t about the pitch pivot axis <NUM>.

Referring to <FIG>, <FIG> and <FIG>, the leading and trailing frame members <NUM>, 210t of the track systems <NUM>, <NUM> define a somewhat scissor-like structure, with lach frame member <NUM>l, <NUM>t pivoting about the pivot <NUM>, and the dampers <NUM>, 300t interconnected therebetween and the axle casing <NUM>. Each one of the leading and trailing wheel-bearing members <NUM>l, <NUM>t is in turn pivotably connected to the leading and trailing frame member <NUM>l, <NUM>t, respectively. The pivoting of each of these structures may assist in reducing the vertical displacements and vibrations transferred from the track systems <NUM>, <NUM> to the chassis <NUM> of the vehicle <NUM> under certain conditions. In some embodiments, the track systems <NUM>, <NUM> further include bushing assemblies operatively connected between the axle assemblies rotatably connecting the wheel assemblies <NUM>l, <NUM>t, <NUM>a, <NUM>b, <NUM>c, <NUM>d to their corresponding component of the frame assembly <NUM>. The bushing assemblies further assist in reducing the vibrations transferred from the track systems <NUM>, <NUM> to the chassis <NUM> of the vehicle <NUM> under certain conditions.

In addition, having the track systems <NUM>, <NUM> with such a scissor-like structure has other advantages in certain situations. For example, as the weight of the vehicle <NUM> increases, for example during harvesting or loading operations, the scissor-like structure can open and a ground-contacting portion of the endless track <NUM> occurs over an increased surface area (i.e. the ground engaging segment <NUM> increases in size as the load borne by the track systems <NUM>, <NUM> increases - at least for some increases in load - depending on the design of a specific track system). As a result, in some circumstances, the pressure applied to the ground by the endless track <NUM> (owing to the weight and load of the vehicle <NUM>) increases at a lower rate than the weight of the vehicle <NUM>. In certain embodiments, this will allow the track systems <NUM>, <NUM> to bear additional loads as compared with conventional track systems.

Referring to <FIG>, <FIG>, and <FIG>, the leading wheel-bearing frame member <NUM>l is directly pivotably connected to the leading frame member <NUM>l about an axis <NUM>l. The leading idler wheel assembly <NUM>l is rotatably connected to the leading wheel-bearing frame member <NUM>l. The leading idler wheel assembly <NUM>l rotates about an axis <NUM>l. A leading idler actuator assembly <NUM>l is connected between the leading wheel-bearing frame member <NUM>l and the leading frame member <NUM>l for adjusting the pivotal positioning of the leading idler wheel assembly <NUM>l relative to the leading frame member <NUM>l. When the leading idler actuator assembly <NUM>l is retracted, as shown in <FIG>, the leading idler wheel assembly <NUM>l pivots about the axis <NUM>l (in the clockwise direction in <FIG>) and is pulled toward the leading frame member <NUM>l. When the leading idler actuator assembly <NUM>l is retracted, the leading ground engaging segment <NUM>l extends above ground (when the track system <NUM> is disposed on flat level ground) as shown in <FIG>. In some circumstances, such as when the track system <NUM> has to travel over a bump or has to get out of a pothole or a ditch, raising the leading idler wheel assembly <NUM>l may assists in overcoming the bump or getting the track system <NUM> out of the pothole or the ditch. In addition, raising the leading idler wheel assembly <NUM>l using the actuator <NUM> may prevent undesirable soil compaction as the track system <NUM> gets out of a pothole or a ditch compared to conventional track systems where the leading idler wheel assembly <NUM>l would remain lowered. In the present embodiment, the leading idler actuator assembly <NUM>l also limits the pivotal motion and provides for a dampened pivotal motion of the leading wheel-bearing frame member <NUM>l and the leading frame member <NUM>l relative to each other about the axis <NUM>l. The leading idler actuator assembly <NUM>l can also be configured to provide an unbiased pivotal motion of the leading wheel-bearing frame member <NUM>l relative to the leading frame member <NUM>.

Referring to <FIG>, the trailing wheel-bearing frame member 230t is directly pivotably connected to the trailing frame member <NUM>l about an axis 224t. The trailing idler wheel assembly <NUM>t is rotatably connected to the trailing wheel-bearing frame member <NUM>t and rotates about an axis <NUM>t. A trailing idler actuator assembly <NUM>t is connected between the trailing wheel-bearing frame member <NUM>t and the trailing frame member <NUM>t for adjusting the pivotal positioning of the trailing idler wheel assembly <NUM>t relative to the trailing frame member <NUM>t. When the trailing idler actuator assembly <NUM>t is retracted, as shown in <FIG>, the trailing idler wheel assembly <NUM>t pivots about the axis <NUM>t (in the counter-clockwise direction in <FIG>) and is pulled toward the trailing frame member 210t. When the trailing idler actuator assembly <NUM>t is retracted, the trailing ground engaging segment <NUM>t extends above ground (when the track system <NUM> is disposed on flat level ground) as shown in <FIG>. In some circumstances, such as when the track system <NUM> is travelling over a bump or is getting out of a pothole or a ditch, raising the trailing idler wheel assembly <NUM>t may assists in overcoming the bump or getting the track system <NUM> out of the pothole or the ditch. In the present embodiment, the trailing idler actuator assembly <NUM>t also limits the pivotal motion and provides for a dampened pivotal motion of the trailing wheel-bearing frame member <NUM>t and the trailing frame member <NUM>t relative to each other. The trailing idler actuator assembly <NUM>t can also be configured to provide an unbiased pivotal motion of the trailing wheel-bearing frame member <NUM>t relative to the trailing frame member <NUM>t.

In other embodiments, the actuator assemblies <NUM>l, <NUM>t could be replaced by electric motors, such as stepper motors, or any other suitable device operatively connected between the leading frame member <NUM>l and the leading wheel-bearing frame member <NUM>l, and the trailing frame member <NUM>t and the trailing wheel-bearing frame member <NUM>t for adjusting the pivotal positioning therebetween.

Referring to <FIG>, upon extension or retraction of the actuator assemblies <NUM>l, <NUM>t, the endless track <NUM> can selectively have the leading ground-engaging segment <NUM>l and/or the trailing ground engaging segment <NUM>t extending on or above the ground surface. Referring to <FIG>, both the leading and trailing actuator assemblies <NUM>l, <NUM>t are retracted and, as mentioned above, the ground engaging segment <NUM> is shorter than in the configurations shown in <FIG>. The configuration of <FIG> can assist in reducing wear of the endless track <NUM> when travelling over hard ground surfaces, such as a paved road. As the amount of endless track <NUM> in ground contact is reduced compared to the configurations shown in <FIG>, rolling resistance of the track system <NUM> and/or wear of the endless track <NUM> are reduced under some conditions. In addition, when the leading ground engaging segment <NUM>l extends above ground, an angle of attack α of the endless track <NUM> when engaging the ground surface is reduced compared to the same angle of attack α in the configuration shown in <FIG> where the endless track <NUM> wraps around the leading idler wheel assembly <NUM>l and contacts the ground. The angle of attack α of the endless track <NUM> shown in <FIG> may reduce wear of the tread <NUM> under some conditions.

Moreover, steering of the track system <NUM> is facilitated when both the leading and trailing actuator assemblies <NUM>l, <NUM>t are retracted, and the track system <NUM> has a behavior that is more akin to a wheel and tire assembly. Thus, under certain conditions such as when the track system <NUM> travels over hard ground surfaces, configuring the track system <NUM> as shown in <FIG> may prove to be advantageous over the configuration shown in <FIG>.

Referring to <FIG>, the leading wheel-bearing frame member <NUM>l includes a tensioner <NUM> having first and second ends <NUM>, <NUM>. The first end <NUM> extends inside a recess <NUM> of the leading wheel-bearing frame member <NUM>l and is rotatably connected to the leading wheel-bearing frame member <NUM>l. A wheel linkage (not shown) is rotatably connected to the leading wheel-bearing frame member <NUM>l at an axis <NUM> (shown as a dashed line in <FIG>) that is offset from the axis <NUM>l. The second end <NUM> of the tensioner <NUM> is rotatably connected to the wheel linkage at a distal tensioning pivot which is offset from the axis <NUM>l. A leading axle assembly (not shown) is operatively connected to the wheel linkage and defines the axis <NUM>l. The distal tensioning pivot and the axis <NUM> are angularly displaced around the axis <NUM>l such that the wheel linkage forms a lever with the axis <NUM> being the fulcrum thereof.

The action of the tensioner <NUM> and the wheel linkage bias the leading axle assembly and the leading idler wheel assembly <NUM>l toward the forward end of the track system <NUM>. In some embodiments, the tensioner <NUM> is used to reduce the variations in the perimeter of the endless track <NUM> due to the pivoting of the leading and trailing frame members <NUM>l, <NUM>t and wheel-bearing frame members <NUM>l, <NUM>t. In some embodiments, the tensioner <NUM> is also operatively connected to the leading idler actuator assembly <NUM>l and/or the trailing idler actuator assembly <NUM>t. When operatively interconnected, the actuator assemblies <NUM>l, <NUM>t and the tensioner <NUM> are operated in collaborative, synergistic fashion so as to reduce the variations in the perimeter of the endless track <NUM> and to prevent damage to the endless track <NUM> and/or any one of the actuator assemblies <NUM>l, 310t and the tensioner <NUM>. In addition, the tensioner <NUM> can be operated so as to increase tension in the endless track <NUM> in some circumstances, such as during a hard braking event. An increased tension in the endless track <NUM> may reduce the risks of lugs <NUM> of the endless track <NUM> skipping on the sprocket wheel <NUM>.

In addition, under certain conditions, if debris becomes stuck between one of the wheel assemblies and the endless track <NUM>, the tensioner <NUM> is configured to apply less biasing force and/or retract so as to reduce variation in the perimeter of the endless track <NUM>. When debris are ejected from the track system <NUM>, the tensioner <NUM> is configured to apply more biasing force and/or extend to provide for adequate tension forces in the endless track <NUM>.

In some embodiments, the tensioner <NUM> is a dynamic tensioning device as described in commonly owned International Patent Application No. <CIT>, entitled "Dynamic Tensioner Locking Device for a Track System and Method Thereof', and published as <CIT>. The content of this application is incorporated herein by reference in its entirety.

Referring to <FIG> and <FIG>, the support wheel assemblies 410a, 410b are rotatably connected to the bogie member <NUM>l, which is pivotably connected to the leading wheel-bearing frame member <NUM>l about the axis <NUM>l and thus forming the leading tandem assembly <NUM>l. As such, the support wheel assemblies <NUM>a, <NUM>b are indirectly pivotably connected to the leading wheel-bearing frame member <NUM>l. Similarly, the support wheel assemblies <NUM>c, <NUM>d are rotatably connected to the bogie member 260t, which is pivotably connected to the trailing wheel-bearing frame member <NUM>t about the axis <NUM>t and thus forming the trailing tandem assembly <NUM>t. As such, the support wheel assemblies <NUM>c, 410d are indirectly pivotably connected to the trailing wheel-bearing frame member <NUM>t.

The various components of the track systems <NUM>, <NUM> are made of conventional materials (e.g. metals and metal alloys in most cases, such as steel) via conventional manufacturing processes (e.g. casting, molding, etc.). The present technology merely requires that each component be suitable for the purpose for which it is intended and the use to which it is to be put. Any material(s) or method(s) of manufacture which produce such components may be used in the present technology.

Referring to <FIG> and <FIG>, the sprocket wheel <NUM> of the track systems <NUM>, <NUM> has the feature of having a rim <NUM> defining apertures <NUM> dimensioned for engagement of the lugs <NUM> therein located inward of the spokes <NUM>. This feature may assist in allowing embodiments of track systems <NUM>, <NUM> to be efficiently mechanically packaged, in embodiments where such is judged to be important. Furthermore, this feature may also reduce mud ingress and build-up in some areas of the track systems <NUM>, <NUM> in some circumstances. This is in turn may lead to reduced maintenance and a reduced risk of premature wear of different components of the track systems <NUM>, <NUM> compared to conventional track systems.

With reference to <FIG>, a third embodiment of the present technology, track system <NUM>, is illustrated. It is to be expressly understood that the track system <NUM> is also merely an embodiment of the present technology. The track system <NUM> includes some elements that are the same as or similar to those described with reference to the track systems <NUM>, <NUM>. Therefore, for simplicity, elements of the track system <NUM> that are the same as or similar to those of the track systems <NUM>, <NUM> have been labeled with the same reference numerals, and will not be described again in detail, unless mentioned otherwise. Adaptations are of course understood to be possible for the components to fit their purpose in each of the embodiments of the track system <NUM>, <NUM>, <NUM>.

Referring to <FIG>, the track system <NUM> includes an attachment assembly <NUM> connectable to the chassis <NUM> of the vehicle <NUM>. The attachment assembly <NUM> includes a multi-pivot assembly <NUM> having longitudinally extending pivots <NUM>. The pivots <NUM> define a roll pivot axis <NUM> of the track system <NUM> (shown as a dashed line in <FIG> and <FIG>). The multi-pivot assembly <NUM> further has a pivot <NUM> extending laterally outwardly. The pivot <NUM> defines a pitch pivot axis <NUM> of the track system <NUM>.

The track system <NUM> further includes a frame assembly <NUM> disposed laterally outwardly from the attachment assembly <NUM> (<FIG>) and connected thereto. The frame assembly <NUM> is a multi-member frame assembly and includes leading and trailing frame members <NUM>l, <NUM>t of similar configuration and structure as the ones described with regard to the track system <NUM>, <NUM>. The leading frame member <NUM>l is pivotably connected to the attachment assembly <NUM> via the pivot <NUM> for pivoting about the pitch pivot axis <NUM> (<FIG>), and the trailing frame member <NUM>t is pivotably connected to the attachment assembly <NUM> via the pivot <NUM> for pivoting about the pitch pivot axis <NUM> (<FIG>) independently from the leading frame member <NUM>l. In other embodiments, the frame assembly <NUM> could be formed of a single frame member connected to the attachment assembly <NUM> and pivoting about the pitch pivot axis <NUM>. The multi-member frame assembly <NUM> also includes leading and trailing wheel-bearing frame members (not shown) pivotably connected to the leading and trailing frame members <NUM>l, <NUM>t respectively. The track system <NUM> further has idler and support wheel assemblies <NUM>l, <NUM>t, <NUM>a, <NUM>10b, <NUM>c, <NUM>d, tandem assemblies <NUM>l, <NUM>t and idler actuator assemblies (only the leading idler actuator assembly <NUM>l is shown) similarly arranged to that of the track systems <NUM>, <NUM>. Thus, the track system <NUM> has the ability to raise and lower the leading and trailing idler wheel assemblies <NUM>l, <NUM>t as described above in reference to the track systems <NUM>, <NUM>. The track system <NUM> can thus have a variable length of the ground engaging segment <NUM> (not shown in <FIG>) of the endless track <NUM> in contact with the ground surface.

An axle casing <NUM> is located above the frame assembly <NUM> and permits the operative connection of the drive shaft <NUM> of the vehicle <NUM> to a sprocket wheel <NUM>. It is noted that in the present embodiment, the drive shaft <NUM> of the vehicle <NUM> does not bear a material portion of the weight of the vehicle <NUM> but only transmits rotational forces to the sprocket wheel <NUM> which does not bear a material portion of the weight of the vehicle <NUM> either. It is also noted that the sprocket wheel <NUM> is differently constructed and differently structured compared to the sprocket wheel <NUM> of the track systems <NUM>, <NUM>. The sprocket wheel <NUM> has spokes <NUM> located along a center plane of the rim <NUM>. Leading and trailing dampers <NUM>, 300t are operatively connected between the axle casing <NUM> and the leading and trailing frame members <NUM>l, 210t respectively.

Still referring to <FIG>, the attachment assembly <NUM> will be described. The multi-pivot assembly <NUM> has a yoke <NUM>. The yoke <NUM> is connectable to the chassis <NUM> of the vehicle <NUM>. In the present embodiment, the yoke <NUM> is connectable to an underside of the chassis <NUM>, but could be configured and structured to be connected to the chassis <NUM> otherwise. The yoke <NUM> has longitudinally spaced apart tabs <NUM> (<FIG>). A pivot arm <NUM> is pivotably connected to the tabs <NUM> of the yoke <NUM> by the longitudinally extending pivots <NUM>. The pivot arm <NUM> is a cruciform member connected simultaneously to the pivots <NUM> and to generally vertically extending pivots <NUM>. The pivots <NUM> define a yaw pivot axis <NUM> of the track system <NUM> (shown as a dashed line in <FIG> and <FIG>). The pivot arm <NUM> is further pivotably connected to a plate <NUM> having vertically spaced apart tabs <NUM>. Through the pivots <NUM>, the plate <NUM> is pivotable about the yaw pivot axis <NUM> relative to the pivot arm <NUM>, and so the plate <NUM> is thus pivotable relative to the yoke <NUM> about the roll and yaw pivot axes <NUM>, <NUM>. It is to be noted that in the present embodiment, the yaw pivot axis <NUM> extends in a direction parallel to the longitudinal center plane <NUM> and along a height direction of the track system <NUM> that is perpendicular to flat level ground. In another embodiment, the yaw pivot axis <NUM> could extend not perpendicularly to flat level ground and could be skewed forward or rearward so as to define a positive or negative caster angle of the track system <NUM>. In another embodiment, the pivot arm <NUM> is structured such that the roll pivot axis <NUM> is skewed with respect to the longitudinal center plane <NUM> and not extending parallel thereto.

As best seen in <FIG> and <FIG>, the plate <NUM> has the pivot <NUM> projecting therefrom and extending laterally outwardly from the attachment assembly <NUM>. The pivot <NUM> is connected to the outward face of the plate <NUM>. The pivot <NUM> can be connected to the plate <NUM> using fasteners and/or any bonding techniques such as welding. In some embodiments, the pivot <NUM> is integrally formed with the plate <NUM>. Loads on the chassis <NUM> of the vehicle <NUM> (including the vehicle's weight) are transferred to the plate <NUM> via the yoke <NUM> when connected to the chassis <NUM>. Loads are then transferred to the pivot <NUM> and then to the leading and trailing frame members <NUM>l, <NUM>t, and so on.

As will be described in more details below, the roll, pitch and yaw pivot axes <NUM>, <NUM>, <NUM> permit degrees of freedom of the track system <NUM> relative to the chassis <NUM> of the vehicle <NUM> that can assist the endless track <NUM> (not shown in <FIG>) to better conform to the ground surface on which it travels and in turn distribute more evenly the load on the entire surface of the ground engaging segment <NUM> of the endless track <NUM>.

The attachment assembly <NUM> further has a camber angle adjusting actuator <NUM> operatively connected between downwardly projecting tabs <NUM> (<FIG>) of the yoke <NUM> and downwardly projecting tabs <NUM> of the plate <NUM>. The camber angle adjusting actuator <NUM> is thus downwardly offset of the pivot axes <NUM>, <NUM>. The actuator <NUM> is a telescopic linear actuator. Referring to <FIG> and <FIG>, retraction and extension of the actuator <NUM> causes pivoting of the frame assembly <NUM> and wheel assemblies <NUM>, 400t, <NUM>a, 410b, 410c, 410d about the roll pivot axis <NUM> so as to adopt a negative camber angle -θ (<FIG>) or a positive camber angle θ (<FIG>). In some embodiments, the camber angle adjusting actuator <NUM> can provide for camber angle adjustment of up to about <NUM> degrees, that is angle θ equals to about <NUM> degrees, but larger or smaller angles θ are contemplated in different embodiments.

As best seen in <FIG>, extension of the actuator <NUM> causes the track system <NUM> to adopt a negative camber angle -θ. Conversely and as seen in <FIG>, retraction of the actuator <NUM> causes the track system <NUM> to adopt a positive camber angle θ. As such, the track system <NUM> has a range of roll motion about the pivot axis <NUM> from about -<NUM> degrees to <NUM> degrees for adjusting the camber angle of the track system <NUM>. The degree of freedom in roll motion about the pivot axis <NUM> permits the track system <NUM> to better conform to a ground surface which is inclined laterally and that defines, for example, a crowned road or a shallow ditch.

As such, the load supported by the frame assembly <NUM> is more evenly distributed between the inward and outward wheels of the idler and support wheel assemblies <NUM>l, <NUM>t, <NUM>a, <NUM>b, <NUM>c, <NUM>d. This more even distribution of the load can reduce wear of the endless track <NUM> as a majority of the area of the ground engaging segment <NUM> is in ground contact instead of just an area below the inward or outward wheels. Wear of the bearings and axle assemblies of each one of the idler and support wheel assemblies <NUM>l, 400t, <NUM>a, <NUM>b, <NUM>c, <NUM>d is also reduced compared to track systems that do not have a degree of freedom in roll motion.

In other embodiments, the actuator <NUM> is replaced by a stepper motor or by any other devices capable of adjusting the positional relationship about the roll pivot axis <NUM> between the attachment assembly <NUM> and the frame assembly <NUM>. Thus, the actuator <NUM> could be replaced by a stepper motor which could adjust the positional relationship by rotating the frame assembly <NUM> relative to the attachment assembly <NUM> about the roll pivot axis <NUM>.

Referring to <FIG> and <FIG>, the attachment assembly <NUM> further has a leading tracking adjusting actuator <NUM>l operatively connected between forwardly projecting tabs <NUM>l of the yoke <NUM> and forwardly projecting tabs <NUM>l of the plate <NUM>, and a trailing tracking adjusting actuator 3150t operatively connected between rearwardly projecting tabs <NUM>t of the yoke <NUM> and rearwardly projecting tabs <NUM>t of the plate <NUM>. The leading and trailing tracking adjusting actuators <NUM>l, <NUM>t are thus longitudinally offset of the pivot axis <NUM>.

Referring to <FIG>, retraction of the actuator <NUM>l and extension of the actuator 3150t cause pivoting of the track system <NUM> about the pivot axis <NUM> so as to adopt a toe-in angle -y (i.e. the leading idler wheel assembly <NUM>l is pivoted inwards and towards the chassis <NUM> of the vehicle <NUM>) relative to a plane <NUM>, which extends parallel to a longitudinal direction of the track system <NUM>, parallel to the center plane <NUM> of the vehicle <NUM> and parallel to a height direction of the track system <NUM>. Referring to <FIG>, extension of the actuator <NUM>l and retraction of the actuator 3150t cause pivoting of the track system <NUM> about the pivot axis <NUM> so as to adopt a toe-out angle γ (i.e. the leading idler wheel assembly <NUM>l is pivoted outwards and away from the chassis <NUM> of the vehicle <NUM>) relative to the plane <NUM>. In some embodiments, the actuators <NUM>l, <NUM>t can provide for tracking angle adjustment of up to about <NUM> degrees, that is angle γ equals to about <NUM> degrees, but larger or smaller angles γ are contemplated in different embodiments. The degree of freedom in yaw motion about the pivot axis <NUM> permits the track system <NUM> to adjust the tracking angle and reduce wear of the endless track <NUM> due to a misalignment of the track system <NUM>. Like the camber angle θ, the toe-in/toe-out angle γ can be dynamically changed using the actuators <NUM>l, <NUM>t depending on, for example, temperature of certain portions of the endless track <NUM>, ground surface conditions and the load of the vehicle <NUM>. As such, premature wear of the endless track <NUM> and other components of the track system <NUM> could be reduced compared to conventional track systems. Furthermore, as mentioned above, the selection of the toe-in/toe-out angle γ may also assist in preserving the integrity of the soil.

In addition, in another embodiment, the actuator <NUM> is omitted and the camber angle θ is adjustable by simultaneously retracting or extending the actuators <NUM>l, 3150t. For example, in such an embodiment, simultaneously extending the actuators <NUM>l, 3150t causes the track system <NUM> to adopt a negative camber angle -θ. Conversely, retracting the actuators <NUM>, 3150t causes the track system <NUM> to adopt a positive camber angle θ. Thus, in this embodiment, the actuators <NUM>, 3150t are operable for selectively adjusting both the camber angle θ and the toe-in/toe-out angle γ of the track system <NUM>.

Moreover, when the track system <NUM> is steerable, for example when operatively connected to a steerable component of the chassis <NUM>, the actuators <NUM>, 3150t could be operatively connected to the steering system of the vehicle <NUM> so as to provide better steering control under some circumstances.

With reference to <FIG>, a fourth embodiment of the present technology, track system <NUM>, is illustrated. It is to be expressly understood that the track system <NUM> is also merely an embodiment of the present technology. The track system <NUM> includes some elements that are the same as or similar to those described with reference to the track systems <NUM>, <NUM>, <NUM>. Therefore, for simplicity, elements of the track system <NUM> that are the same as or similar to those of the track systems <NUM>, <NUM>, <NUM> have been labeled with the same reference numerals, and will not be described again in detail, unless mentioned otherwise. Adaptations are of course understood to be possible for the components to fit their purpose in each of the embodiments of the track system <NUM>, <NUM>, <NUM>, <NUM>.

The track system <NUM> is for use with a towed vehicle <NUM> having a chassis <NUM> and an axle extending laterally outwardly from the chassis <NUM> for connection to the track system <NUM>. The chassis <NUM> supports the various components of the towed vehicle <NUM>. In some embodiments, the towed vehicle <NUM> is an agricultural vehicle and supports agricultural implements such as planters, sprayers or similar devices. However, the track system <NUM> could be used on many different types of towed vehicles that serve many different functions. The track system <NUM> does not have a sprocket wheel and has a pill shape when viewed from the side.

Referring to <FIG>, the track system <NUM> includes an attachment assembly <NUM> (shown in <FIG>) connectable to the chassis <NUM> of the vehicle <NUM>. The attachment assembly <NUM> includes a pillow block bearing assembly <NUM>. The pillow block bearing assembly <NUM> has an axis <NUM>. When the track system <NUM> is connected to the vehicle <NUM>, the axle extending laterally outwardly from the chassis <NUM> is coaxial with the axis <NUM>, and is operatively connected to the pillow block bearing assembly <NUM>. The track system <NUM> is rotatable about the axis <NUM> with respect to the chassis <NUM> of the vehicle <NUM> since the axle is received inside the pillow block bearing assembly <NUM>. As such, when the vehicle <NUM> is towed on a slopped terrain, the track system <NUM> can pitch positively or negatively about the axis <NUM> to conform to the contour of the terrain.

The attachment assembly <NUM> is connected to an outwardly extending bracket <NUM>. Cylindrical bushing assemblies (not shown) are provided in longitudinally extending recesses <NUM> of the bracket <NUM>. Pins are connected to the bushing assemblies so as to prevent their rotation with respect to the bushing assemblies. A wheel-bearing frame member <NUM> is fixedly connected to the pins. When the endless track <NUM> travels on a transversally inclined ground surface, such as a crowned road, the wheel bearing frame member <NUM> causes twisting in a circumferential direction in the cylindrical bushing assemblies, allowing the wheel-bearing frame member <NUM>, the wheel assemblies and the endless track <NUM> to pivot about a roll axis <NUM> with respect to the attachment assembly <NUM> and the bracket <NUM>. In some embodiments, the cylindrical bushing assemblies further assist in reducing the vibrations transferred from the track system <NUM> to the chassis <NUM> of the vehicle <NUM> under certain conditions.

An actuator <NUM> is operatively connected between an inward portion of the bracket <NUM> and the wheel-bearing frame member <NUM>. Retraction of the actuator <NUM> causes the wheel-bearing frame member <NUM> to adopt a positive camber angle θ, by pivoting about the axis <NUM>. Conversely, extending the actuator <NUM> causes the wheel-bearing frame member <NUM> to adopt a negative camber angle -θ, by pivoting about the axis <NUM>. Thus, in this embodiment, the actuator <NUM> is operable for selectively adjusting the camber angle θ of the track system <NUM>.

With reference to <FIG>, a fifth embodiment of the present technology, track system <NUM>, is illustrated. It is to be expressly understood that the track system <NUM> is also merely an embodiment of the present technology. The track system <NUM> includes some elements that are the same as or similar to those described with reference to the track systems <NUM>, <NUM>, <NUM>, <NUM>. Therefore, for simplicity, elements of the track system <NUM> that are the same as or similar to those of the track systems <NUM>, <NUM>, <NUM>, <NUM> have been labeled with the same reference numerals, and will not be described again in detail, unless mentioned otherwise. Adaptations are of course understood to be possible for the components to fit their purpose in each of the embodiments of the track systems <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

The track system <NUM> has a frame assembly <NUM> including leading and trailing frame members <NUM>l, <NUM>t pivoting about a pivot <NUM> which projects laterally outwardly relative to the chassis <NUM> of the vehicle <NUM>. The pivot <NUM> defines a pitch pivot axis <NUM>. The leading frame member <NUM>l is pivotably connected to the pivot <NUM> about the pitch pivot axis <NUM>. The trailing frame member <NUM>t is pivotably connected to the pivot <NUM> about the pitch pivot axis <NUM> independently from the leading frame member <NUM>l. A damper <NUM> interconnects the leading and trailing frame members <NUM>l, <NUM>t. The damper <NUM> is located laterally outwardly of the sprocket wheel <NUM>. In other embodiments, the damper <NUM> is located laterally inwardly of the sprocket wheel <NUM>. In some embodiments, the damper <NUM> is replaced by a coil spring, an air spring, a hydropneumatic spring or the like. Having the leading and trailing frame members <NUM>l, <NUM>t interconnected by the damper <NUM> limits the pivotal motion one relative to another with respect to the pitch pivot axis <NUM>.

The positioning of the damper <NUM> between upper portions of the leading and trailing frame members <NUM><NUM>, <NUM>t allows for a relatively long stroke of the damper <NUM>. As a result, the damping action of the damper <NUM> is generally more refined than in conventional track systems where the stroke of a damping cylinder is shorter. Such configuration provides for a smoother damping action of the damper <NUM> and may reduce the risks of fully compressing the damper <NUM>. Under certain conditions, vibrations that are due to the ground surface on which the track system <NUM> travels and transferred to the leading and trailing frame members <NUM>, 5210t are dampened by the damper <NUM>.

In some embodiments, the damper <NUM> has variable damping characteristics as described in commonly owned International Patent Application No. <CIT>, entitled "Progressive Damping System for a Track System" and published as <CIT>. The content of this application is incorporated herein by reference in its entirety.

It is also to be noted that the track system <NUM> has a support wheel assembly <NUM>a directly rotatably connected to the leading wheel-bearing frame member <NUM>l. As such, there is no leading tandem assembly <NUM>l in this embodiment, but there is a trailing tandem assembly <NUM>t indirectly connecting the support wheel assemblies 410b, 410c to the trailing wheel-bearing frame member 230t. In some embodiments, the track system <NUM> further includes bushing assemblies operatively connected between the axle assemblies rotatably connecting the wheel assemblies <NUM>l, <NUM>t, <NUM>a, <NUM>b, <NUM>c to their corresponding component of the frame assembly <NUM>. The bushing assemblies further assist in reducing the vibrations transferred from the track system <NUM> to the chassis <NUM> of the vehicle <NUM> under certain conditions.

With reference to <FIG> and <FIG>, a sixth embodiment of the present technology, track system <NUM>, is illustrated. It is to be expressly understood that the track system <NUM> is also merely an embodiment of the present technology. The track system <NUM> includes some elements that are the same as or similar to those described with reference to the track systems <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. Therefore, for simplicity, elements of the track system <NUM> that are the same as or similar to those of the track systems <NUM>, <NUM>, <NUM>, <NUM>, <NUM> have been labeled with the same reference numerals, and will not be described again in detail, unless mentioned otherwise. Adaptations are of course understood to be possible for the components to fit their purpose in each of the embodiments of the track systems <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

The track system <NUM> has a frame assembly <NUM> which includes a frame member <NUM>. The frame member <NUM> is connected to the chassis <NUM> of the vehicle <NUM> such that the frame member <NUM> does not pivot about a pitch pivot axis relative to the chassis <NUM>. Leading and trailing wheel-bearing frame members <NUM>l, <NUM>t are pivotably connected to the frame member <NUM>. A leading idler actuator assembly <NUM>l is operatively connected between the frame member <NUM> and the leading wheel-bearing frame member <NUM>l, and a trailing idler actuator assembly <NUM>t is operatively connected between the frame member <NUM> and the trailing wheel-bearing frame member 230t. Retraction of the idler actuator assemblies <NUM>, <NUM>t raises the leading and trailing idler wheel assemblies <NUM>l, <NUM>t above ground (when the track system <NUM> is on a level ground surface), as described above with reference to the track system <NUM> and <FIG>. As described above, the leading and trailing idler actuator assemblies <NUM>l, <NUM>t can also be configured to provide an unbiased pivotal motion of their corresponding wheel-bearing frame member <NUM>, 230t relative to the frame members <NUM>l, 210t.

When the vehicle <NUM> travels on a slopped terrain, the track system <NUM> cannot pitch positively or negatively to conform to the contour of the terrain. However, by selectively retracting and extending the idler actuator assemblies <NUM>l, <NUM>t, the track system <NUM> is capable of positioning the idler wheel assemblies <NUM>l, <NUM>t such that the endless track <NUM> engages the terrain and allow the track system <NUM> to travel on the slopped terrain. This feature may assist in allowing embodiments of the track system <NUM> to be efficiently mechanically packaged, in embodiments where such is judged to be important.

In some embodiments, the track system <NUM> has structures and actuators such as the ones described above with reference to the track systems <NUM>, <NUM>, <NUM>, <NUM>, <NUM> permitting a motion of the frame member <NUM> relative to the chassis <NUM> of the vehicle <NUM> about roll and/or yaw pivot axes.

Referring to <FIG>, the vehicle <NUM> is schematically represented with a track system <NUM>, according to one embodiment of the present technology, operatively connected at each corner of the vehicle <NUM>. It is contemplated that any one of the embodiments of the track systems <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> could be operatively connected to the vehicle <NUM>. For simplicity, the track system <NUM> is schematically represented, but it is to be understood that the following description is directed to any one of the embodiments of the track systems <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and to their respective components and features. The forward travel direction <NUM> of the vehicle <NUM> is also indicated.

The track system <NUM> is operatively connected to the vehicle <NUM> at the front right corner, the track system <NUM>' is operatively connected to the vehicle <NUM> at the front left corner, a track system <NUM>r is operatively connected to the vehicle <NUM> at the rear right corner, and a track system <NUM>r' is operatively connected to the vehicle <NUM> at the rear left corner. A track system controller <NUM>, schematically represented by a triangle in <FIG>, is operatively connected to each track system <NUM>, <NUM>', <NUM>r, <NUM>r' and controls the operation of the actuator assemblies <NUM>l, <NUM>t, <NUM>, <NUM>, <NUM>l, 3150t, <NUM> and dampers <NUM>, <NUM>l, <NUM>t described above. Each track system controller <NUM> is powered by the electrical system of the vehicle <NUM>, and each of the actuator assemblies <NUM>l, <NUM>t, <NUM>, <NUM>, <NUM>l, 3150t, <NUM> is operatively connected to a power source. Each track system controller <NUM> includes a memory and a processing unit capable of receiving and sending signals. The dashed lines in <FIG> indicate that the track system controllers <NUM> are operatively interconnected to one another.

As will be described below, each track system controller <NUM> controls the operation of the actuator assemblies <NUM>l, <NUM>t, <NUM>, <NUM>, <NUM>l, <NUM>t, <NUM> of its corresponding track system <NUM>, <NUM>', <NUM>r, <NUM>r' depending on various input signals received from the operator of the vehicle <NUM> and/or from a plurality of monitoring sensors <NUM>, schematically represented in <FIG> as squares. As such, each track system controller <NUM> is programmable and capable of running predetermined sequences and actions so as to control the operation of the actuator assemblies <NUM>, 310t, <NUM>, <NUM>, <NUM>, 3150t, <NUM> its corresponding track system <NUM>, <NUM>', 40r, 40r' automatically or using manual override in accordance with a predetermined objective.

In the present embodiment, the monitoring sensors <NUM> are mounted at various locations on the vehicle <NUM> and on each one of the track systems <NUM>, <NUM>', 40r, 40r'. As will be described below, the monitoring sensors <NUM> are used for determining at least indirectly a state of each one of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' and/or a condition of the ground surface on which the vehicle <NUM> travels. It is to be understood that the monitoring sensors <NUM> can be embedded within, affixed, mounted or connected to any of the suitable components of the vehicle <NUM> and track systems <NUM>, <NUM>', <NUM>r, <NUM>r'. The monitoring sensors <NUM> may be operatively connected to the track system controllers <NUM> via wire or via a wireless connection. The operative connection between the monitoring sensors <NUM> and the track system controllers <NUM> is shown by the dashed lines in <FIG>.

In some embodiments, the monitoring sensors <NUM> include temperature sensors capable of determining the temperature of different components of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r'. For example, temperature sensors can be embedded within or disposed proximate the endless tracks <NUM>, the idler and support wheel assemblies <NUM>l, <NUM>t, <NUM>a, <NUM>b, <NUM>c, <NUM>d and/or the actuator assemblies <NUM>l, 310t, <NUM>, <NUM>, <NUM>l, <NUM>t, <NUM> for accurate temperature measurement of certain portions of each component. The temperature sensors could be thermal radiation thermometers, thermocouples, thermistors, or any other suitable type of sensing device capable of sensing temperature. In an embodiment where the temperature sensors are embedded in the endless tracks <NUM>, they are disposed to determine the temperature at various locations on the endless track <NUM>, for example on the inward and/or outward portions of the endless track <NUM>, near or on the inner surface <NUM>, near or on the drive lugs <NUM> and/or near or on the outer surface <NUM> of the endless track <NUM>. The collected temperature data is sent as signals to the corresponding track system controller <NUM>. After processing the temperature data, the track system controller <NUM> determines a corresponding output signal related to the actuation of any one of the actuator assemblies <NUM>l, <NUM>t, <NUM>, <NUM>, <NUM>l, <NUM>t, <NUM> based on the signals received from the temperature sensors. In addition, the track system controller <NUM> is operable to identify which temperature sensor sends a given signal based on a unique identifier associated with each temperature sensor.

For example, in order to reduce risks of damaging the endless tracks <NUM> due to excessive heat generation as the endless tracks <NUM> are driven, the track system controller <NUM> of the track system <NUM> operates each one of the actuator assemblies <NUM>l, <NUM>t, <NUM>, <NUM>, <NUM>l, <NUM>t, <NUM>, alone or in combination, to correct the positioning of the frame assembly <NUM> and the idler and support wheel assemblies <NUM>l, <NUM>t, <NUM>a, <NUM>b, <NUM>c, <NUM>d relative to the chassis <NUM> and/or the ground surface. In an illustrative scenario, the temperature sensors determine that the inward portions of the endless track <NUM> have temperature readings that are higher than the temperature readings of the outward portions of the endless track <NUM>, and that the difference in temperature readings is above a predetermined threshold. Based on the signals received from the temperature sensors, the system controller <NUM> sends a signal to extend or retract the actuator <NUM> (or actuators <NUM>, <NUM>t) so as to adjust the camber angle θ of the track system <NUM> in order to more evenly distribute the load across the ground engaging segment <NUM> of the endless track <NUM>. A more even load distribution across the ground engaging segment <NUM> may not only assist in reducing undesirable heat generation in certain portions of the endless tracks <NUM>, but may also reduce soil compaction when driving on soft ground surface. As such, the track system <NUM> is capable of dynamically adjusting the camber angle θ based on data collected by the monitoring sensors <NUM> and processed by the track system controller <NUM>.

In another illustrative scenario, the inward portions of the endless track <NUM> of the track system <NUM> have temperature readings that are higher than the temperature readings of the outward portions of the endless track <NUM>, and that the difference in temperature readings is above a predetermined threshold. Based on the signals received from the temperature sensors, the system controller <NUM> of the track system <NUM> sends a signal to extend or retract the actuators <NUM>l, 3150t so as to adjust the toe-in/toe-out angle y of the track system <NUM>. Proper alignment of the endless track <NUM> relative to the chassis <NUM> of the vehicle <NUM> may also assist in reducing undesirable heat generation and premature wear in certain portions of the endless track <NUM>. As such, the track system <NUM> is also capable of dynamically adjusting the toe-in/toe-out angle γ based on data collected by the monitoring sensors <NUM> and processed by the track system controller <NUM>.

In other embodiments, the monitoring sensors <NUM> also include, in addition or in replacement of the temperature sensors, load cells (e.g. load transducers). The load cells can be piezoelectric load cells, hydraulic load cells, pneumatic load cells, or any other suitable type of cells capable of sensing a load applied thereto. In some embodiments, the load cells are provided at various locations on the vehicle <NUM> (as represented in <FIG>), such as under the tank, container or cargo area, in order to monitor a payload of the vehicle <NUM> and to determine the location of the centre of gravity of the vehicle <NUM>. In one scenario where the vehicle <NUM> travels on a laterally inclined ground surface, the track system controllers <NUM> collectively determine the location of the centre of gravity of the vehicle <NUM> using data received from the load cells located on the vehicle <NUM>. The track system controllers <NUM> are then capable of sending signals to one another to extend or retract their corresponding actuator <NUM> (or actuators <NUM>l, <NUM>t) so as to adjust the camber angle θ of their corresponding track systems <NUM>, <NUM>', <NUM>r, <NUM>r' in order to more evenly distribute the load across the ground engaging segment <NUM> of each of the endless tracks <NUM>. This is another example of the track system <NUM> being capable of dynamically adjusting the camber angle θ based on data collected by the monitoring sensors <NUM> and processed by one or more of the track system controllers <NUM>.

In some embodiments, additional load cells are disposed in various components of each track system <NUM>, <NUM>', <NUM>r, <NUM>r'. For example, in embodiments where load cells are embedded within the endless track <NUM> in the inward and outward portions thereof, the load data of each load cell is sent as signals to the corresponding track system controller <NUM>. In situations where the inward portion of the endless track <NUM> have load readings that are higher than the load readings of the outward portions of the endless track <NUM>, and that the difference in load readings is above a predetermined threshold, the system controller <NUM> sends a signal to extend or retract the actuator <NUM> (or actuators <NUM>l, <NUM>t) so as to adjust the camber angle θ of the corresponding track system <NUM>, <NUM>', <NUM>r, <NUM>r' in order to more evenly distribute the load across the ground engaging segment <NUM>. This way, soil compaction issues could be reduced compared to conventional track systems as the track system controllers <NUM> dynamically adjust the position of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' relative to the chassis <NUM> of the vehicle <NUM> (i.e. adjusting the camber angle θ and/or the toe-in/toe-out angle y) so as to more evenly distribute the load born by each track system across the ground engaging segment <NUM> of its respective endless track <NUM>.

In other embodiments where each damper <NUM>, <NUM>, 300t is also operatively connected to its corresponding track system controller <NUM>, the load readings sent as signals by the load sensors located on the vehicle <NUM> to the track system controller <NUM> also enable to dynamically adjust certain properties of the dampers <NUM>, <NUM>l, <NUM>t, such as the damping ratio, as a function of the load of the vehicle <NUM>. As such, certain properties of the damper <NUM> of each track system <NUM>, <NUM>', <NUM>r, <NUM>r' are dynamically modified depending on the load readings.

In yet other embodiments, the monitoring sensors <NUM> also include strain gauges. The strain gauges could be located, for example, at the pivot joints connecting the actuator assemblies <NUM>l, <NUM>t, <NUM>, <NUM>, <NUM>l, 3150t, <NUM> to the frame assembly <NUM>, <NUM> or at the pivot joints of the frame assembly <NUM>, <NUM>. In some embodiments, the strain gauges are connected to the frame members <NUM>l, <NUM>t, the wheel-bearing frame members <NUM>l, <NUM>t and/or to the bogie members <NUM>l, <NUM>t. In an illustrative scenario, a strain gauge is located at the pivot axis <NUM>l of the track system <NUM>, the track system <NUM> is initially in the configuration shown in <FIG>, travels in the forward travel direction <NUM> and starts sinking down in a recess composed of soft soil. When a driving torque is applied to the sprocket wheel <NUM>, the strain gauge has a reading that is above a certain threshold and sends a signal to the track system controller <NUM>. The track system controller <NUM> also receives a signal from the vehicle <NUM> that a driving torque is applied to the drive shaft <NUM> for turning the sprocket wheel <NUM> and that the speed of the vehicle <NUM> does not increase. The track system controller <NUM> sends a signal to retract the actuator assemblies <NUM>l, <NUM>t so as to change the configuration of the track system <NUM> from the one shown in <FIG> to the one shown for example in <FIG>.

In some embodiments, the monitoring sensors <NUM> include accelerometers. The accelerometers could be located, for example, on the axle casing <NUM> of each track system <NUM>, <NUM>', <NUM>r, <NUM>r'. In such an embodiment, the accelerometers detect the vibrations that have not been dampened or not dampened to a sufficient amount by the track systems <NUM>, <NUM>', <NUM>r, <NUM>r'. The accelerometers measure the vertical acceleration to which the axle casing <NUM> is subjected and send this data as signals to the corresponding track system controller <NUM>. Upon reception of the vertical acceleration signals, the track system controller <NUM> processes this data and sends a signal to a cabin-mounted suspension assembly <NUM> schematically represented in <FIG>. The cabin-mounted suspension assembly <NUM> is capable of moving the seat and/or the entire cabin that the operator occupies to subject it to vertical accelerations that have frequencies and amplitudes adapted to cancel out or reduce the vertical accelerations that the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' experience and that are conducted to the cabin. As a result of the cooperation between the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' and the cabin-mounted suspension assembly <NUM>, an operator located in the cabin receives less vibrations from the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' and would therefore feel more comfortable than if the vehicle <NUM> was equipped with conventional track systems.

In yet other embodiments, the accelerometers are capable of detecting vibrations in the proximity of various components of the track systems <NUM>, <NUM>', <NUM>r, <NUM>0r'. Signals generated by the accelerometers are sent to the track system controller <NUM> which determines over time the usage and wear of the components of the track systems <NUM>, <NUM>', <NUM>r, 40r'. This may be useful to obtain general information related to the condition of various components of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r', perform an analysis of the frequencies of the acceleration data and/or perform at the right time predictive maintenance operations to reduce risks of component failures. For example, the acceleration and vibration data related to bearings, pivot pins, seals and the gearbox <NUM> could be analyzed in real time and/or populate a database that could be analyzed to determine early signs of excessive wear or failure of components of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r'.

In some embodiments, the monitoring sensors <NUM> include inclinometers. The inclinometers could be located, for example, on the components of the frame assembly <NUM> and could be configured to send signals to the track system controller <NUM> indicative of the camber angle θ of the axle assemblies connecting the idler and support wheel assemblies <NUM>l, <NUM>t, <NUM>a, <NUM>b, <NUM>c, <NUM>d (<FIG> and <FIG>). Similar to what has been described above, the signals generated by the inclinometers are provided to the track system controller <NUM> which operates the actuator assembly <NUM> to adjust the positioning of the frame assembly <NUM> and the idler and support wheel assemblies <NUM>, 400t, <NUM>a, 410b, 410c, 410d relative to the chassis <NUM> and/or the ground surface in accordance with a predetermined objective. In some embodiments, the signals provided by the inclinometers could be used by the track system controller <NUM> to assess and calibrate the operation of the actuator assembly <NUM> and/or to assess the wear of the tread <NUM> of the endless track <NUM>.

In some embodiments, the monitoring sensors <NUM> include fluid property sensors. The fluid property sensors could be located, for example, within the axle assemblies connecting the idler and support wheel assemblies <NUM>, 400t, <NUM>a, 410b, 410c, 410d to the frame assembly <NUM>. The fluid property sensors assess various properties and characteristics of the fluid contained within axle assemblies, such as viscosity, density, dielectric constant, temperature, presence of water, presence of suspended contaminants and wear debris. The data collected from the fluid property sensors could assist the track system controller <NUM> to determine the condition and wear of some of the components of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r'.

In some embodiments, the monitoring sensors <NUM> could include actuator assembly position sensors. The actuator assembly position sensors could include linear displacement transducers connected to one or more of the actuator assemblies <NUM>l, <NUM>t, <NUM>, <NUM>, <NUM>l, <NUM>t, <NUM> that could send signals to the track system controller <NUM> indicative of the position and/or length of the corresponding actuator assembly <NUM>l, <NUM>t, <NUM>, <NUM>, <NUM>l, <NUM>t, <NUM>. Using the signals provided by the linear displacement transducers, the track system controller <NUM> could assess the status of extension/retraction of the actuator assemblies <NUM>l, <NUM>t, <NUM>, <NUM>, <NUM>l, <NUM>t, <NUM> and assist in determining how to operate them. The actuator assembly position sensors could also include inclinometers connected to, for example, the leading and trailing idler actuator assemblies <NUM>l, <NUM>t. Using references and baselines, the inclinometers could send signals to the track system controller <NUM> indicative of the position and/or length of the corresponding actuator assembly <NUM>l, <NUM>t. These signals could also assist the track system controller <NUM> to assess the status of extension/retraction of the actuator assemblies <NUM>l, <NUM>t and assist in determining how to operate them.

In some embodiments, the monitoring sensors <NUM> include position sensors capable of assessing a geographical location of each one of the track systems <NUM>, <NUM>', <NUM>r, 40r'. The assessment of the geographical location may be useful for the track system controllers <NUM> which could record data related to, for example, strain at pivot joints and vertical acceleration to which the track systems <NUM>, <NUM>', <NUM>r, <NUM>0r' are subjected in conjunction with the geographical location. External sources of information could also be stored in the memory of the track system controllers <NUM>, such as detailed road plans, topography data and agricultural field terrain data. As such, in some embodiments, the track system controller <NUM> learns optimal configurations of each of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' for each particular geographic location of the vehicle <NUM>. In some embodiments, the track system controller <NUM> is configured to prime and/or configure in real-time the actuator assemblies <NUM>, 310t, <NUM>, <NUM>, <NUM>, 3150t, <NUM> so that each of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' has the more appropriate configuration for the ground surface on which it travels. In some embodiments, the track system controller <NUM> is configured to prime the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' for each given geographical location by adjusting one or more of the actuator assemblies <NUM>l, <NUM>t, <NUM>, <NUM>, <NUM>l, <NUM>0t, <NUM> thereof just before the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' reach each given geographical location. In some cases, and for some types of terrain, this allows the track system controller <NUM> to distribute the vehicle's weight relatively more evenly across the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' and/or more evenly into the terrain across each ground engaging segment <NUM> of each of the endless tracks <NUM> of each of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r'. In some cases, and for some types of terrain, this allows reducing soil compaction. In other words, in embodiments where the monitoring sensors <NUM> include position sensors, the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' become location-aware devices and they are capable of adapting their configuration accordingly. In some embodiments, the monitoring sensors <NUM> do not include position sensors and the tack system controller <NUM> receives the geographical location of the vehicle <NUM> that is provided by a position sensor (such as a GPS device) of the vehicle <NUM>.

For example, in a situation where the track system controller <NUM> determines that the geographical location of the track system <NUM> corresponds to a paved road, the track system controller <NUM> sends a signal to retract the actuator assemblies <NUM>, 310t so that the track system <NUM> be configured as illustrated in <FIG> and <FIG>, for example. In another situation where the track system controller <NUM> determines that the geographical location of the track system <NUM> corresponds to an agricultural field having soil sensitive to ground compaction, the track system controller <NUM> sends a signal to extend the actuator assemblies <NUM>, 310t so as to distribute the load born by then track system <NUM> over a greater ground engaging segment <NUM>, such as in the configuration shown in <FIG> and <FIG>.

Moreover, as each of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r can have its geographical location monitored by the position sensors, the track system controllers <NUM> of the front-mounted track systems <NUM>, <NUM>' are capable of communicating with the track system controllers <NUM> of the rear-mounted track systems 40r, <NUM>r' so that they adjust their configuration based on the data collected by the monitoring sensors <NUM> of the front-mounted track systems <NUM>, <NUM>'. In an illustrative scenario, the vehicle <NUM> travels in a straight line, the track systems <NUM>, <NUM>r are initially in the configuration shown in <FIG> and the track system <NUM> is driven into a pothole. The geographical location of that pothole is recorded by the track system controller <NUM> of the track system <NUM> and sent to the track system controller <NUM> of the track system 40r. The leading and trailing idler actuators <NUM>l, <NUM>t of the track system <NUM> are retracted as shown in <FIG> so that the track system <NUM> is configured to drive itself out of the pothole, as described above. As the vehicle <NUM> travels forward, the track system controller <NUM> of the track system 40r monitors the geographical location thereof and before the track system <NUM>r is driven in the same pothole, the track system controller <NUM> of the track system <NUM>r sends a signal to retract the leading and trailing idler actuators <NUM>l, <NUM>t of the track system <NUM>r as shown in <FIG>. Thus, when the track system <NUM>r is driven into the pothole, the track system <NUM>r is already configured so that driving out of that same pothole is facilitated.

In some embodiments, the track system controller <NUM> is configured to adjust the configuration of each of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r based on the data collected by the monitoring sensors <NUM> in time for the track systems <NUM>, <NUM>', <NUM>r, <NUM>r arriving at particular terrain conditions, such that the configuration of cach of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r is optimized for the particular terrain conditions. In an illustrative scenario, the vehicle <NUM> at one point in time was travelling at a given speed and a given direction monitored by the track system controller <NUM> and traveled over a pothole with the front right track system <NUM>. At that time, the track system controller <NUM> had detected the existence and the geographic location of the pothole, and stored this data in its memory. The next time when the vehicle <NUM> travels proximate the geographic location of the pothole, the track system controller <NUM> may determine that the vehicle <NUM> will drive over the pothole again, but this time with its front left track system <NUM>'. In such a case, the track system controller <NUM> may determine a particular time associated with the impending driving over the pothole by the front left track system <NUM>' using the geographic location of the front left track system <NUM>' derived as described above, and the speed and direction of the vehicle <NUM>. The track system controller <NUM> may then retract the leading idler actuator <NUM>l of the front left track system <NUM>' just before the front left track system <NUM>' reaches the pothole, and may thereby reduce the impact that the front left track system <NUM>' will experience upon entering the pothole. In some embodiments, the track system controller <NUM> may also retract the trailing idler actuator <NUM>t of the front left track system <NUM>'. In some cases this may assist the front left track system <NUM>' in driving out of the pothole.

Once the front left track system <NUM>' exits the pothole, the track system controller <NUM> may extend the leading idler actuator <NUM> and/or the trailing idler actuator <NUM>t of the front left track system <NUM>' to the "pre-pothole" position(s). In some embodiments, the track system controller <NUM> is further configured to adjust the leading idler actuator <NUM> and/or the trailing idler actuator <NUM>t while a given one of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' is engaged with a pothole or other obstacle in order to improve traction.

In some embodiments, the monitoring sensors <NUM> also include ground surface sensors. The ground surface sensors can include devices such as sonars, hygrometers, penetrometers, ultrasonic devices, microwave-based devices, radar devices and lidar devices capable of generating an accurate representation of the ground on which the vehicle <NUM> travels or is about to travel. The sonars, hygrometers and penetrometers could provide data related to, for example, composition of the soil, moisture content, air content, etc., and the ultrasonic, microwave-based, radar and lidar devices could provide an accurate representation of the ground surface profile and potential hazards. The data of the ground surface sensors is sent as signals to the track system controllers <NUM> which then determine the more appropriate configuration of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' based on the assessed representation of the ground surface. For example, in a situation where the ground surface sensors and the track system controllers <NUM> determine that the ground surface is relatively hard and bumpy, the track system controllers <NUM> send signals to retract the actuator assemblies <NUM>l, <NUM>t to configure the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' in the configuration shown in <FIG>. In another situation where the ground surface sensors and the track system controllers <NUM> determine that the ground surface is relatively moist and soft and composed of loosely packed particles, the track system controllers <NUM> send signals to extend the actuator assemblies <NUM>l, <NUM>t to configure the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' in the configuration shown in <FIG>.

Based on the above description, it is understood that in certain embodiments the monitoring sensors <NUM> could include all of the above-described sensors, and that in other embodiments, only a subset of the above-described sensors would be included. The monitoring sensors <NUM> could thus enable the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' to anticipate the properties of the ground surface on which they are about to travel and/or anticipate obstacles to overcome, and permit the modification of the configuration of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' accordingly.

As described above, the monitoring sensors <NUM> are thus capable of determining a state of the track system <NUM> and/or a ground surface condition of the ground on which the track system <NUM> travels. Determining a state of the track system <NUM> includes, and is not limited to, (i) determining the temperature of different components and/or portions of the track system <NUM>, (ii) determining the load supported by different components and/or portions of the track system <NUM>, (iii) determining the strain undergone by different components and/or portions of the track system <NUM>, (iv) determining the vibration undergone by different components and/or portions of the track system <NUM>, (v) determining wear of different components and/or portions of the track system <NUM>, (vi) determining the inclination of different components and/or portions of the track system <NUM>, (vii) determining the status of extension/retraction of the actuator assemblies <NUM>, <NUM>l, <NUM>t, <NUM>l, <NUM>t, <NUM>, and (viii) determining the location of different components and/or portions of the track system <NUM>. Determining a ground surface condition of the ground on which the track system <NUM> travels includes, and is not limited to, (i) determining whether the ground surface is a paved road or an agricultural field having soil sensitive to ground compaction, (ii) determining the hazards and the profile of the ground surface, and (iii) determining at least one of a composition, a moisture content, and an air content of the soil.

In summary and as described in more details above, the track system controllers <NUM> and the monitoring sensors <NUM> could assist in, among other things, (i) planning predictive maintenance operations, (ii) recording relevant data related to the properties of the ground surface on which the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' travel (for mapping purposes for example), (iii) maintaining an appropriate tension in the endless tracks <NUM> depending on the properties of the ground surface, (iv) increase the comfort of the operator of the vehicle <NUM> should the vehicle <NUM> be equipped with a cabin mounted suspension assembly <NUM> operatively connected to one or more track systems <NUM>, <NUM>', <NUM>r, <NUM>r', (v) reducing soil compaction issues on sensitive ground surfaces, and (vi) improving traction of the endless track <NUM> of each of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r'.

Referring now to <FIG>, a master control unit <NUM> is provided on the vehicle <NUM> and operatively connected to control systems <NUM> of the vehicle <NUM>. The track system controllers <NUM> of the track systems <NUM>, <NUM>', <NUM>r, <NUM>r' and at least some of the monitoring sensors <NUM> are operatively connected to the master control unit <NUM>. The master control unit <NUM> includes a processing unit, a memory, is programmable and is configured to send and receive signals from/to the track system controllers <NUM> and the vehicle <NUM>. As the master control unit <NUM> is simultaneously operatively connected to the track system controllers <NUM> and to the vehicle <NUM>, data provided by the control systems <NUM> of the vehicle <NUM> is taken into account by the master control unit <NUM> and supplemented to the signals received from the monitoring sensors <NUM> so as to have a more complete representation of the status of the vehicle <NUM> and track systems <NUM>, <NUM>', <NUM>r, <NUM>r'.

In certain situations, the master control unit <NUM> can override the track control systems <NUM> in controlling the operation of the actuator assemblies <NUM>l, 310t, <NUM>, <NUM>, <NUM>l, <NUM>t, <NUM> in accordance with a predetermined objective. In some circumstances, the master control unit <NUM> is connected to a remote network <NUM> via a communication device <NUM>, and data provided by the track system controllers <NUM> and/or the control systems <NUM> of the vehicle <NUM> are collected by the master control unit <NUM>, uploaded to the remote network <NUM> by the communication device <NUM> and processed by a remote processing unit <NUM> using, in some instances, supplemental data related to, for example, weather records, soil condition, etc. Processed data and/or control signals for the track system controllers <NUM> obtained from the remote processing unit <NUM> are downloaded to the master control unit <NUM> via the remote network <NUM> and communication device <NUM> so that the master control unit <NUM> controls the track system controllers <NUM> according to this processed data and/or control signals.

Claim 1:
A track system (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) for use with a vehicle (<NUM>) having a chassis (<NUM>), characterized in that the track system comprises:
an attachment assembly (<NUM>, <NUM>) connectable to the chassis of the vehicle, the attachment assembly including
a first pivot (<NUM>, <NUM>) extending vertically and defining a yaw pivot axis (<NUM>, <NUM>) of the track system, and
a second pivot (<NUM>, <NUM>) extending laterally and defining a pitch pivot axis (<NUM>, <NUM>) of the track system,
a frame assembly (<NUM>, <NUM>, <NUM>, <NUM>) disposed laterally outwardly from the attachment assembly and connected to the attachment assembly, the frame assembly including at least one wheel-bearing frame member (<NUM>l, <NUM>t);
at least one actuator (<NUM>l, 3150t, <NUM>) connected between the attachment assembly and the frame assembly for pivoting the frame assembly about the yaw pivot axis;
a leading idler wheel assembly (<NUM>l) at least indirectly connected to the at least one wheel-bearing frame member;
a trailing idler wheel assembly (<NUM>t) at least indirectly connected to the at least one wheel-bearing frame member;
at least one support wheel assembly (410a, 410b, 410c, 410d) at least indirectly connected to the at least one wheel-bearing frame member and disposed between the leading idler wheel assembly and the trailing idler wheel assembly; and
an endless track (<NUM>) extending around the leading idler wheel assembly, the trailing idler wheel assembly, and the at least one support wheel assembly.