WO2017201396A1

WO2017201396A1 - A modular self-propelled vehicle for supporting and operating a device

Info

Publication number: WO2017201396A1
Application number: PCT/US2017/033524
Authority: WO
Inventors: Nathan D. DOCKTER; Scott A. Rempe; Kent L. Thompson
Original assignee: Vermeer Manufacturing Co
Current assignee: Vermeer Manufacturing Co
Priority date: 2016-05-19
Filing date: 2017-05-19
Publication date: 2017-11-23
Anticipated expiration: 2018-11-19

Abstract

Modular self-propelled vehicles for supporting and operating a device that is releasably connectable to the vehicle. Example devices include agricultural devices. The vehicle may include a device mount for releasably attaching the device. In some embodiments, the vehicle includes rear drive wheels and front caster wheels.

Description

A MODULAR SELF-PROPELLED VEHICLE FOR

SUPPORTING AND OPERATING A DEVICE

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62/338,724, filed May 19, 2016, which is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

[0002] The field of the disclosure relates to modular self-propelled vehicles for supporting and operating a device that is releasably connectable to the vehicle.

BACKGROUND

[0003] Agricultural operations involve a number of implements, some of which may be towed implements and others which may include dedicated propulsion systems (e.g., sprayers). In particular, forage gathering involves a number of towed implements such as mowers and mower conditioners, rakes, hay mergers and balers.

[0004] Towed implements are typically towed behind a tractor which may limit the field of vision of the operator. The tractor and implement assembly are relatively long which makes tuming such towed assemblies difficult. The tractor and implement are pivotally attached and the implement limits the tuming radius of the tractor.

[0005] A need exists for vehicles that can mount to and operate a number of devices such as agricultural devices and for vehicles that are self-propelled, that are highly maneuverable and that improve the operator ride while providing sufficient maneuverability. [0006] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

SUMMARY

[0007] One aspect of the present disclosure is directed to a modular self- propelled vehicle for supporting and operating a detachable device. The vehicle has a longitudinal axis and comprises a chassis and first and second rear drive wheels connected to the chassis. The first and second rear drive wheels each have a rotational axis. The vehicle includes drive systems for independently controlling a drive speed of each of the first and second rear drive wheels so that the speed of the first drive wheel is selectively controllable relative to a speed of the second drive wheel and so that differences in the first drive wheel speed and the second drive wheel speed enable vehicle steering. A front caster wheel is connected to the chassis. The vehicle includes a device mount for releasably attaching the device.

[0008] Various refinements exist of the features noted in relation to the above-mentioned aspects of the present disclosure. Further features may also be incorporated in the above-mentioned aspects of the present disclosure as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to any of the illustrated embodiments of the present disclosure may be incorporated into any of the above-described aspects of the present disclosure, alone or in any combination.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a perspective view of a modular self-propelled vehicle; [0010] Figure 2 is a side view of the vehicle with a baling device mounted thereto;

[0011] Figure 3 is a front view of the vehicle with a baling device mounted thereto;

[0012] Figure 4 is a perspective view of the vehicle with a baling device mounted thereto;

[0013] Figure 5 is a schematic view of the self-propelled vehicle showing the drive systems;

[0014] Figure 6 is a perspective view of a caster assembly of the vehicle;

[0015] Figure 7 is cross-sectional side view of the vehicle showing a baling chamber;

[0016] Figure 8 is cross-sectional side view of the vehicle showing a baler drive system;

[0017] Figure 9 is perspective view of the vehicle showing the engine mounting brackets;

[0018] Figure 10 is a perspective view of the vehicle with two wheel-rake tool bars mounted thereto;

[0019] Figure 1 1 is a perspective view of the vehicle with a mower conditioner mounted thereto;

[0020] Figure 12 is a perspective view of the vehicle with a hay merger mounted thereto; and

[0021] Figure 13 is a perspective view of a device mount of the vehicle.

[0022] Corresponding reference characters indicate corresponding parts throughout the drawings. DETAILED DESCRIPTION

[0023] A modular self-propelled vehicle (which may be referred to herein as the "base vehicle") for supporting and operating various agricultural devices is generally referred to as "1" in Figure 1. The vehicle 1 is a base vehicle to which various devices such as agricultural devices may be attached. While the description and Figures below may show and/or reference a baling device, it should be noted that baling device is shown as an exemplary device and the descriptions are applicable to the base vehicle itself and/or a base vehicle that includes one or more different devices attached thereto. While the device may, in some embodiments, be described as an agricultural device, in other embodiments the connectable device may be suitable for use in other fields.

Base Vehicle

[0024] With reference to Figure 2, the base vehicle 1 includes first and second rear drive wheels 17 that are driven by first and second motors disposed in the drive wheels. The rear drive wheels 17 each have a rotational axis Rn about which the drive wheels 17 rotate. In the illustrated embodiment, the wheels 17 have a common rotational axis Rn. In other embodiments the wheels 17 are offset from each other and have different axes of rotation. The drive wheels 17 are attached to the chassis 9.

[0025] The rear wheels 17 are fixed to the chassis 9 such that the wheels 17 maintain parallel alignment with a longitudinal axis A (Fig. 4) of the vehicle 1 (i.e., do not pivot with respect to the chassis 9). In some embodiments, the rear drive wheels 17 are not suspended from the chassis 9.

[0026] The longitudinal axis A (Fig. 4) of the vehicle 1 extends from a front 55 (Fig. 2) to a rear 57 of the vehicle 1. As referenced herein, the "front" of the vehicle 1 refers to a leading portion or end of the vehicle 1 relative to the longitudinal axis during its conventional operation. The "rear" refers to the trailing portion or end relative to the longitudinal axis A during its conventional operation. Similarly, the terms "front caster wheels" and "rear wheels" refer to the position of the wheels relative to the direction of travel of the vehicle 1 during its conventional operation. The vehicle 1 also includes a lateral axis B (Fig. 4) that extends from a first side 58 to a second side 59 of the vehicle 1 and that is transverse to the longitudinal axis A. The vehicle 1 also includes a vertical axis C (Fig. 3).

[0027] With reference to Figure 5, the first and second drive wheels 17 are each driven and controlled by separate drive systems 15. The caster wheels 27 are freely pivotable (i.e., are not steered or otherwise controlled). As a result, the first and second caster wheels 27 self-align with the direction of travel of the vehicle while it is steered by the difference in the speed of rotation of the drive wheels 17.

[0028] Each drive system 15 has a drive motor 23 for rotating the drive wheel 17 forward or backward. The drive motors 23 may be hydraulic motors that are driven by a pump 20 that is powered by the engine 101. Each drive wheel 17 may be controlled by a separate circuit (i.e., separate hydraulic pumps 20 with fluid lines 22 connected to the drive wheel motors 23). The first and second pumps 20 may be hydrostatic, variable displacement pumps. In some embodiments, fixed displacement or variable displacement motor(s) may be used.

[0029] The wheels 17 are powered and rotated independently by the drive systems 15. Accordingly, the wheels 17 can be rotated at different speeds by driving the motors at different speeds. For example, the motors 23 may receive different amounts of fluid from the respective pumps 20 to differentiate the speed of the wheels 17. Separate fluid lines 22 extend between each pump 20 and drive motor 23 to independently rotate the wheels 17. The direction of fluid flow may be forward or reverse to independently rotate the wheels forward or reverse to propel the vehicle forward, reverse, or through an arc (e.g., as during steering). The vehicle 1 may also be steered in more aggressive manners in which one wheel remains stationary while the other wheel is rotated, or a zero-turn-radius mode where the drive wheels are rotated in opposite directions.

[0030] In some operating conditions (e.g., travel or "highway" modes) the first and second drive wheels 17 are powered equally (e.g., with a differential system linking the drive systems) and a caster wheel steering system (not shown) may be used to steer the vehicle. Suitable steering systems may include adjustable length tie-rods (e.g., three position cylinders) connected to a steering mechanism such as a steering wheel. The tie-rods may be fixed in length in a caster-wheel steering mode and variable in length in non-caster wheel steering modes (e.g., by use of three-position cylinders which float in non-caster wheel steering modes and are locked in caster wheel steering modes). Any steering system which enables caster wheel steering in a caster wheel steering mode may be used unless stated otherwise.

[0031] The vehicle 1 includes a control system to control the drive wheels 17 and front caster wheels 27 based on input(s) from an operator. The control system includes a control unit 80, speed and direction control device 78, a mode selector 79 and steering mechanism which is shown as a steering wheel 67. The speed and direction control device 78, mode selector 79 and steering wheel 67 may be controlled from the operator station 13.

[0032] The control unit 80 includes a processor and a memory. The processor processes the signals received from various sensors, selectors and control devices of the system. The memory stores instructions that are executed by the processor.

[0033] The mode selector 79 allows the operator to select a desired mode of operation (i.e., drive wheel steering mode or caster wheel steering mode). The control unit 80 receives the signal from the mode selector 79 and controls the mode of the steering system in response to the signal. The mode selector 79 may be, for example, part of a touch screen, a soft key, toggle switch, selection button or any other suitable interface for selecting the steering mode.

[0034] The speed and direction control device 78 is typically hand- operated and may be a sliding lever that that causes an increase in forward speed as the lever is slid forward of a neutral position and an increase in reverse direction as the lever is slid rearward of the neutral position. The direction and speed control device 78 produces a signal in response to its position and the signal is transmitted to the control unit 80. The control unit 80 produces an output signal transmitted to the hydraulic pumps 20 that drive the rear wheels 17. The speed may also be controlled by a throttle that controls the engine speed. The vehicle 1 may be stopped by moving the direction and speed control device 78 to a zero-speed setting and/or by operating foot brake levers.

[0035] In the illustrated embodiment, steering may be performed by a steering mechanism shown as a steering wheel 67 which regulates the steering system. For example, in the drive wheel steering mode, a sensor 81 measures the direction and angle of the steering wheel 67 and sends signals to the control unit 80. The control unit 80 produces a signal that is transmitted to the hydraulic pumps 20 to independently regulate the rotational speeds of the first and second drive wheels 17 (i.e., the rotation speed and direction of rotation of each drive wheel 17).

[0036] In other embodiments, speed and/or steering may be controlled by different operator controls such as wheel levers, digital inputs, joysticks, dual sticks, and headsets.

[0037] In some embodiments, the self-propelled vehicle 1 is configured to operate autonomously. The vehicle 1 may include sensors (e.g., cameras, GPS sensors and the like) that sense the position of the windrow and/or that may sense the position of the vehicle in the field. The vehicle 1 may also include a controller that sends signals to the first and second rear wheel pumps or to various actuators to independently control the first and second rear drive wheels. In some embodiments, the field in which the vehicle is propelled is mapped and the field map is used to autonomously control the operation of the vehicle in the field. In such embodiments, the vehicle may include a riding station to carry an operator or the operator station may be eliminated.

[0038] The self-propelled vehicle 1 includes first and second front caster wheels 27 that are pivotally connected to the chassis 9 about a vertical pivot axis (which may be offset from the vertical axis, i.e., may have a caster angle). The term "caster wheel" includes a wheel mounted to a frame or chassis at a generally vertically oriented caster pivot so that the caster wheel is able to swivel about the caster pivot.

[0039] The first and second caster wheels 27 swing below a portion of the chassis 9. The front caster wheels 27 are spaced to allow the windrow of crop or forage material to pass between the front caster wheels 27 and engage the pickup device 1 1. As shown in Figure 3, teeth 29 of the pick-up device 1 1 are positioned between the front caster wheels 27 relative to a lateral axis B (Fig. 4) of the vehicle 1. In some embodiments, the front caster wheels 27 are separated by at least five feet or at least about seven feet.

Similarly, the rear wheels 17 are spaced to allow the baling device 5 (Fig. 2) to be positioned between the rear wheels. In some embodiments, the vehicle 1 includes a single front caster wheel (e.g., one front caster wheel centered relative to the lateral axis of the vehicle). [0040] The front caster wheels 27 are independently suspended from the chassis to absorb forces transmitted during travel over uneven terrain. The front caster wheels 27 pivot with respect to the chassis 9 about their pivot axis to allow the wheels 27 to be aligned with the direction of travel of the vehicle 1 and as a response to the differential speed of the first and second drive wheels 17. In some embodiments, the front caster wheels 27 are freely pivotal and turn only as a response to the differential speed of the rear drive wheels 17. In other embodiments, the front caster wheels 27 are steered (e.g., controlled to coordinate turning with rear drive wheels or steered independently of the rear drive wheels 17).

[0041] Each front caster wheel 27 has a rotational axis R27 (Fig. 4) about which the front caster wheels 27 rotate. In the illustrated embodiment, the wheels 27 have a common rotational axis R27.

[0042] The front caster wheels 27 may be part of first and second swivel caster assemblies 31. Generally the first and second swivel caster assemblies 31 and subframes 41 described below are symmetric and description herein of an assembly or subframe also applies to the second assembly or subframe (e.g., description of a hub of the assembly indicates that the first assembly has a first hub and that the second assembly has a second hub). Each assembly 31 includes a hub 35 (Fig. 6) and a caster shaft 37 (which may be referred to as a "kingpin") that rotates within the hub 35. The swivel caster assemblies 31 may include bushings or bearings within the hub 35 that allow for rotation of the shaft 37 within the hub 35. Each caster shaft 37 is connected to a leg assembly 42 that connects to the front caster wheel axle. In the illustrated embodiment, the leg assembly 42 includes a single leg that attaches to an inner side of the wheel axle. In other embodiments, the leg assembly includes two legs that connect to the axle of the front caster wheel on each side of the wheel (as with a caster fork).

[0043] The hub 35 and shaft 37 form a swivel joint 43. The first and second front caster wheels 27 of the caster assemblies 31 are each connected to a subframe 41 by a swivel joint 43. The subframes 41 are suspended from the chassis 9 by a mechanism having a suspension element 49, shown as a hydraulic cylinder in the illustrated embodiment. The cylinder may be connected to an accumulator in the suspension system. Each subframe 41 is also pivotally attached to the chassis 9 at an outer pivot point Pi and an inner pivot point P₂. In this arrangement, the chassis 9 is supported by the subframes 41 and the chassis 9 and components carried by the chassis (e.g., operator station) may move up and down relative to the subframes 41 as the vehicle 1 travels over uneven terrain.

[0044] As shown in Figure 6, the subframe 41 has two arms 45, 47 that extend from the chassis 9. The swivel joint 43 is at the point at which the arms 45, 47 meet and is forward of the inner and outer pivot points Pi, P2 relative to a longitudinal axis A (Fig. 4) of the vehicle 1. The swivel joint 43 is also outward to both the inner and outer pivot points Pi, P2 relative to the lateral axis B (Fig. 4) of the apparatus 1 (i.e., the outer pivot point Pi of each subframe 41 is positioned between the inner pivot point P2 and the point of attachment of the suspension element 49 relative to the lateral axis B).

[0045] As shown in Figure 2, the first and second front caster wheels 27 (i.e., the axes of rotation R₂7 of each wheel) are offset from the swivel joint 43 relative to the longitudinal axis A (Fig. 4) of the vehicle. The offset allows the first and second front caster wheels 27 to self-align with the direction of travel of the vehicle 1 as the vehicle is steered by differences between the speeds of the rear wheels 17. The offset of the caster wheels (i.e., distance between the axis of rotation R₂7 of the wheel and the swivel joint 43 relative to the longitudinal axis A) may be at least 4 inches, at least about 8 inches or from about 8 to about 20 inches. These ranges are exemplary and other ranges may be used unless stated otherwise.

[0046] In other embodiments and/or in different modes of operation the front caster wheels 27 are steered (e.g., travel/highway modes). In such embodiments, the offset may be eliminated.

[0047] The caster assemblies 31 allow the first and second front caster wheels 27 to self-align with the direction of travel of the vehicle while it is steered by the difference in the speed of rotation of the rear wheels 17. In the illustrated embodiment, the first and second front caster wheels 27 pivot independently from each other. In other embodiments, the first and second front caster wheels 27 are connected through linkages (e.g., as in an Ackerman steering arrangement).

[0048] As shown in Figure 2, the rear wheels 17 have a diameter larger than the front caster wheels 27. In some embodiments, the ratio of the diameter of the rear wheels 17 to the diameter of the front caster wheels is at least about 1.25: 1 or at least about 1.5: 1 or even at least about 3 : 1.

[0049] The vehicle 1 includes an engine 101 (e.g., gas or diesel powered engine) that drives one or more hydraulic pumps which in turn power the various hydraulic motors and cylinders (e.g., first and second drive wheel motors, baling chamber motor, pick-up device motor, pick-up device lift cylinder, tailgate cylinder and/or ramp cylinder). The engine 101 also provides power for the electrical systems of the vehicle 1. The engine 101 is between the rotational axes Rn of the rear drive wheels 17 and the rotational axes R-27 of the front caster wheels 27.

[0050] The engine 101 is arranged transverse to the longitudinal axis A of the vehicle 1. The engine 101 is supported by engine isolators and mounting brackets 11 1 (Fig. 9) that are attached to the chassis 9. The engine 101 includes a radiator 105 (Fig. 2) and a cooling fan 109 (Fig. 7) that forces air across the radiator 105. The fan 109 directs air in a direction transverse to the longitudinal axis A.

[0051] The engine 101 is disposed between the baling chamber 62 mounting position and the operator station 13. As referenced herein, the "operator station" refers to the seat and controls for steering and controlling the speed of the vehicle 1 and/or for controlling the device. The operator station 13 is enclosed in a cab 121 (Fig. 2). As shown in Figure 2, the operator station 13 is forward of the rotational axis Rn of the rear drive wheels 17 and is also forward to the engine 101. The operator station 13 is partially aligned with the rotational axis R27 of the front caster wheels 27 (the steering wheel is aligned with the rotational axis R27 while the other controls and operator seat are rearward to the rotational axis R₂₇).

[0052] A distance Di (Fig. 2) separates the rotational axis Rn of the rear drive wheels and the rotation axis R27 of the front caster wheels 27. In some embodiments, the distance D₂ between the rear wheel rotational axis Rn and the operator station 13 is at least about 0.4*Di (i.e., the operator station is at least about 40% forward of the distance between the axis Rn, R₂₇), or at least about 0.5*Di or even at least about 0.6*D₁. The cab 121 may also be least about 0.4*Di or at least about 0.5*Di forward of the rotational axis Rn of the rear drive wheels 17. Modular Components

[0053] The modular self-propelled vehicle 1 (Fig. 1) includes one or more device mounts for releasably attaching one or more devices. The device may be an agricultural device such as a mower and mower conditioner, merger, baler, rake, sprayer, broadcast spreader, fruit or nut harvester, or the like. Other devices include salt and aggregate spreaders, shipping containers (e.g., trash, commodities, household items or other goods), construction devices, trenchers, concrete cutters, and the like.

[0054] The device mounts of the base vehicle may include plates 92 (Fig. 13) having bolt holes 93 for attaching corresponding mounting plates of the device or other methods of mounting may be used (e.g., mounting pins, ball and sockets, hitch receivers and the like). The device may include hydraulic couplers for attachment to a hydraulic system of the vehicle 1. In some embodiments, the device is attached directly to a hydraulic cylinder of the base vehicle 1.

[0055] The device mounts may be positioned on the vehicle 1 at any position in which the device is operable (e.g., toward the rear, front, or anywhere between the rear and front of the vehicle).

[0056] The term "modular" as used herein should not be viewed to imply that the vehicle 1 is compatible with different types of devices. For example, the modular self-propelled vehicle 1 may include one or more device mounts to allow the device to be pivoted off of the vehicle chassis 9 (Fig. 2) to provide access to the device for maintenance or to replace the device with a new device (e.g., upon wear or failure of an agricultural device) or to install a larger-sized device (e.g., larger baler) or a different model of device.

[0057] In some embodiments, the modular self-propelled vehicle 1 comprises first and second device mounts for mounting two different devices. The vehicle may include additional mounts (e.g., third, fourth, fifth or more device mounts). In some embodiments, the vehicle includes a device mount for attaching a baler device and a second mount for connecting to a second agricultural implement selected from a rake, a mower, hay merger and sprayer.

[0058] As shown in Figures 2-9, a baling device 5 including an expandable baling chamber 62 may be mounted to the vehicle 1 to form a bale. In the illustrated embodiment, the baling device 5 is cylindrical to form cylindrical bales (i.e., round bales). The baling device 5 operates by utilizing a series of bale forming belts 64 (Fig. 7) routed around a series of rollers 66a-l. Alternatively, a single bale forming belt may be utilized. Additionally, the baling device 5 includes a drive gear 65 (Fig. 8) that is driven by a baler motor. The drive gear 65 is connected to several rollers 66 to rotate the belts 64 during bale formation and during bale wrapping sequences. The baling device 5 also includes a plurality of belt tighteners 72 (Fig. 7). It should be noted that any of the known round baler device arrangements may be used as baler device 5 including, variable chamber balers (as shown) and fixed chamber balers. The baler device may include a single drive motor as shown or may include two or more drive motors.

[0059] The baler device 5 includes a pick-up device 11 (Fig. 3) to pick-up crop or forage material. The pick-up device 11 is shown in a raised position. During baling, the pick-up device 11 is in a lowered position in which the rotating teeth 29 of the device 11 contact the crop or forage material and direct it toward the baling chamber 62. As material is picked up by the pick-up device 11, and deposited in the baling chamber 62, the material is compressed by the plurality of bale forming belts 64. Rotation of the pickup device 11 is driven by separate motor (e.g., hydraulic motor).

[0060] Tension is maintained in the bale forming belts 64 by one or more belt tighteners 72 to ensure a properly compressed bale. Once a full bale (not shown) is formed, the vehicle is stopped and a wrapping sequence is commenced by a wrapping mechanism 82. The wrapping mechanism 82 is configured to apply one or more layer of wrap material to the outer circumference of the completed bale. The wrap material is spooled on a roll. A linear actuator directs wrap material into contact with the outer perimeter of the completed bale. The bale device drive motor powers the belts to cause the bale to continue to rotate to pull the wrap material from the supply roll and onto the circumference of the bale. After the wrap sequence is complete, the wrap material is cut. The wrap material can include a variety of materials suitable for retaining the shape of the bale, protecting the bale and for limiting exposure of the bale to moisture. Rope-like twine, sheet-type netwrap, plastic or fabric sheets, or film-type sheets are just some examples of commonly used wrap material. [0061] Once the wrapping sequence is completed, the completed bale is ejected from the baling chamber 62 by initiating opening of a tailgate 74. The baling device 5 includes a discharge ramp 90 that forces the bale to roll away from the vehicle 1 to clear the tailgate 74 as the tailgate closes. The ramp 90 may be lowered as the tailgate 74 opens and raised before the tailgate closes to push the bale further away from the tailgate.

[0062] The baling chamber 62 has a central axis C that is transvers to the longitudinal axis A of the vehicle and that intersects the center of mass of a completed bale (i.e., the rotational axis of the bale as in round bales) after the bale is formed in the chamber 62. The central axis C of the baling chamber 62 may be separated from the rotational axis Rn of the rear drive wheels 17 relative to the longitudinal axis A of the vehicle 1 by a distance.

[0063] The central axis C of the baling chamber 62 may be positioned on the vehicle such that at least about 60% or even at least about 70% (e.g., 75% to about 80%) of the weight of the vehicle is supported by the rear wheels 17. In various embodiments, this may be achieved by positioning the center axis C of the baling chamber 62 at or behind or at or behind the rotational axis Rn of the rear drive wheels 17 relative to the longitudinal axis A of the vehicle 1 (i.e., is between the rotational axis Rn and the rear end 57 of the vehicle 1). In some embodiments, the center axis C of the baling chamber 62 may be forward to the rotational axis Rn of the rear drive wheels 17 with the distance D₃ between the central axis C of the baling chamber 62 and the rotational axis Rn being less than about 0.25*Di even less than about 0.15*Di or even less than about 0.10*Di.

[0064] The central axis of a completed bale (i.e., fully formed bale) may be determined by any suitable manner. In some embodiments, the central axis is determined by determining the outer circumference of the bale as defined by the position of the baler rollers 66 and/or belts 64.

[0065] Referring now to Figure 10, the modular self-propelled vehicle is shown mounted to two wheel-rake tool bars 95a, 95b. The tool bars 95a, 95b extend laterally from the front of the apparatus to allow the formed windrow to pass between the rear tires of the apparatus. As shown in Figure 10, the tool bars 95a, 95b are mounted to the chassis between the front and rear wheels. In other embodiments, the tool bars 95a, 95b are mounted forward of the front wheels. [0066] As shown in Figure 11 , a mower conditioner 97 is mounted to the chassis towards the front of the modular self-propelled vehicle. The mower conditioner may discharge a windrow of cut forage material such that the material passes through the front and rear wheels of the apparatus.

[0067] A hay or forage merger 99 may be mounted to the modular self- propelled vehicle as shown in Figure 12. In the illustrated embodiment, the hay merger is mounted to the chassis between the front and rear wheels. In other embodiments, the merger may be mounted forward to the front wheels or behind the rear wheels.

[0068] In some embodiments, sprayer components (not shown) may be mounted to the chassis of the modular self-propelled vehicle. The sprayer may have a sprayer tank mounted to the chassis where the baler device 5 shown in Figure 2 is positioned. Spray booms that extend laterally outward from the vehicle may be mounted to the chassis.

[0069] It should be noted that while a single device is shown and described as being attached to the base vehicle, two or more devices may be mounted at any one time unless stated otherwise (e.g., (1) baler device and wheel rake or (2) mower conditions and merger or any other suitable combination).

[0070] Compared to conventional vehicles, the modular self-propelled vehicles of embodiments of the present disclosure have several advantages. The vehicle is modular and may mount to a variety of devices such as agricultural devices. By incorporating front caster wheel assemblies and hydraulic rear drive wheels that rotate independently, the vehicle is highly maneuverable and is able to turn within its own footprint (i.e., in a counter-steer arrangement or zero-turn radius). This allows the vehicle to be turned quickly such as for reversing direction upon the vehicle reaching the end of row in the field or, when a bale device is mounted, for repositioning prior to bale discharge to prevent bales from rolling down an incline during bale discharge. By positioning the engine transverse to the longitudinal axis of the vehicle, the wheelbase may be shortened and chaff to be blown cross way.

[0071] By positioning the operator station relatively forward and near the front caster wheels (e.g., by overlapping the operator station and/or cab with the rotational axes of the front caster wheels), the operator has a clear field of vision of the approaching crop or forage material. In addition, the operator station is near the suspension system (e.g., with the cab and/or operator station being disposed above the suspension system) which improves the operator ride and reduces operator fatigue. In embodiments in which devices are mounted forward of the rear wheels and are supported by the chassis, the operator may also have a clear field of view of the mounted device (e.g., wheel rake) and/or the turning profile of the vehicle and device may be reduced.

[0072] As used herein, the terms "about," "substantially," "essentially" and "approximately" when used in conjunction with ranges of dimensions, concentrations, temperatures or other physical or chemical properties or characteristics is meant to cover variations that may exist in the upper and/or lower limits of the ranges of the properties or characteristics, including, for example, variations resulting from rounding, measurement methodology or other statistical variation.

[0073] When introducing elements of the present disclosure or the embodiment(s) thereof, the articles "a", "an", "the" and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," "containing" and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. The use of terms indicating a particular orientation (e.g., "top", "bottom", "side", etc.) is for convenience of description and does not require any particular orientation of the item described.

[0074] As various changes could be made in the above constructions and methods without departing from the scope of the disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawing[s] shall be interpreted as illustrative and not in a limiting sense.

Claims

WHAT IS CLAIMED IS:

1. A modular self-propelled vehicle for supporting and operating a detachable device, the vehicle having a longitudinal axis, the vehicle comprising: a chassis; first and second rear drive wheels connected to the chassis, the first and second rear drive wheels each having a rotational axis; drive systems for independently controlling a drive speed of each of the first and second rear drive wheels so that the speed of the first drive wheel is selectively controllable relative to a speed of the second drive wheel and so that differences in the first drive wheel speed and the second drive wheel speed enable vehicle steering; a front caster wheel connected to the chassis; and a device mount for releasably attaching the device.

2. The modular self-propelled vehicle as set forth in claim 1 in combination with the device, the device being an agricultural device selected from the group consisting of a baler, a rake, a mower, a hay merger, a sprayer, and a broadcast sprayer.

3. The modular self-propelled vehicle as set forth in claim 1 or claims 2 wherein each drive system comprises a hydraulic drive motor.

4. The modular self-propelled vehicle as set forth in any one of claims 1 to 3 wherein the vehicle comprises an engine for propelling the vehicle, the engine being disposed between a rotational axis of the front caster wheels and the rotational axes of the rear drive wheels.

5. The modular self-propelled vehicle as set forth in claim 4 comprising a radiator and a cooling fan, the cooling fan directing air across the radiator in a direction transverse to the longitudinal axis.

6. The modular self-propelled vehicle as set forth in any one of claims 1 to 5 wherein the front caster wheel has a rotational axis, the vehicle comprising one or more engine mounting brackets, each engine mounting bracket being disposed between the rotational axis of the front caster wheel and the rotational axes of the rear drive wheels.

7. The modular self-propelled vehicle as set forth in any one of claims 1 to 6 further comprising a cab, the cab overlapping the rotational axis of the front caster wheel.

8. The modular self-propelled vehicle as set forth in claim 7 further comprising an operator station, the a portion of the operator stations overlapping the rotational axis of the front caster wheel.

9. The modular self-propelled vehicle as set forth in any one of claims 1 to 8 further comprising an operator station, the front caster wheel having a rotational axis, wherein a distance Di separates the rotational axes of the rear drive wheels and the rotational axis of the front caster wheel, there being a distance D₂ between the rear wheel rotational axis and the operator station, D₂ being at least about 0.4Di or at least about 0.5Di or at least about O.6D₁.

10. The modular self-propelled vehicle as set forth in any one of claims 1 to 9 wherein the front caster wheel is a first front caster wheel, the vehicle comprising a second front caster wheel connected to the chassis, each front caster wheel being mounted on a suspension mechanism to allow the front wheels to move toward the chassis relative to the vertical axis.

11. The modular self-propelled vehicle as set forth in claim 10 further comprising first and second subframes, the first front caster wheel forming a first swivel joint with the first subframe, the second front caster wheel forming a second swivel joint with the second subframe, the first and second subframes being suspended from and pivotally attached to the chassis.

12. The modular self-propelled vehicle as set forth in claim 11 wherein each subframe is connected to the chassis at an outer pivot point and at an inner pivot point.

13. The modular self-propelled vehicle as set forth in claim 12 wherein the vehicle has a lateral axis that is transverse to the longitudinal axis, the baling vehicle comprising first and second suspension elements, the first suspension element being attached to the chassis and to the first subframe, the outer pivot point of the first subframe being disposed between the inner pivot point of the first subframe and the point of attachment between the first suspension element and the first subframe relative to the lateral axis, the second suspension element being attached to the chassis and to the second subframe, the outer pivot point of the second subframe being disposed between the inner pivot point of the second subframe and the point of attachment between the second suspension element and the second subframe relative to the lateral axis.

14. The modular self-propelled vehicle as set forth in claim 13 wherein the first swivel joint is disposed forward to the inner and outer pivot points of the first subframe and the second swivel joint is disposed forward to the inner and outer pivot points of the second subframe.

15. The modular self-propelled vehicle as set forth in any one of claims 10 to 14 wherein the first front caster wheel is offset from the first swivel joint and the second front caster wheel is offset from the second swivel joint.

16. The modular self-propelled vehicle as set forth in any one of claims 1 to 15 wherein the front caster wheel is part of a swivel caster assembly, the caster assembly comprising a hub and a caster shaft that rotates within the hub.

17. The modular self-propelled vehicle as set forth in any one of claims 1 to 16 wherein the first and second rear drive wheels are fixed to the chassis to maintain alignment with the longitudinal axis.

18. The modular self-propelled vehicle as set forth in any one of claims 1 to 17 wherein the first and second rear drive wheels are not suspended from the chassis.

19. The modular self-propelled vehicle as set forth in any one of claims 1 to 19 wherein the first and second rear drive wheels have a diameter and the front caster wheels have a diameter, the ratio of the diameter of the rear wheels to the diameter of the front caster wheels being at least 1.25: 1 or even at least about 3: 1.

20. The modular self-propelled vehicle as set forth in any one of claims 1 to 19 wherein the front caster wheel is freely pivotal with respect to the chassis such that the front caster wheel pivots with respect to the chassis in response to differences in the first drive wheel speed and the second drive wheel speed.

21. The modular self-propelled vehicle as set forth in any one of claims 1 to 19 wherein the front caster wheel is steered to assist in turning during one or more modes of operation.

22. The modular self-propelled vehicle as set forth in any one of claims 1 to 21 comprising at least two device mounts for attaching two different agricultural devices.

23. The modular self-propelled vehicle as set forth in any one of claims 1 to 22 in combination with a baler device and a second device selected from, the group consisting of a rake, a mower, a hay merger and sprayer.

24. The modular self-propelled vehicle as set forth in claim 23 wherein the device mount is a first device mount that is configured to be mounted to a baling device, the modular self-propelled vehicle comprising a second device mount for mounting the second device.

25. The modular self-propelled vehicle as set forth in any one of claims 1 to 24 wherein the device mount comprises a releasable plate, mounting pin, ball and socket or hitch receiver.

26. The modular self-propelled vehicle as set forth in any one of claims 1 to 25 wherein the front caster wheel is mounted on a suspension mechanism to enable the front wheel to move toward the chassis relative to the vertical axis.