EP0136910A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Agricultural tractors
Assignee: STANDISH Ltd
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Filing: 1984-10-02
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Granted: —
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Expires: 2004-10-02
Abstract
Abstract In a tractor (1) having a frame (2, 3) and four wheels (20, 21, 50, 51), each wheel is driven by a hydrostatic motor (126, 128, 129, 127) and is mounted on an arm (23, 24, 53, 54) which is pivotable relative to the frame. The tractor has a power unit (111) which drives pumps (113,114,115,145,155) for supplying hydraulic fluid under pressure. Two (113, 114) of said pumps are drive pumps for supplying hydraulic fluid under pressure to respective pairs (126, 127 and 128, 129) of said wheel motors. A hydraulic piston and cylinder device (31, 32, 61, 62) is mounted between the frame and each of said pivotable arms (23,24, 53, 54) on which the wheels are mounted. One of the cylinder and piston of each of the devices is associated with the frame and the other of the cylinder and piston of the device is associated with the respective pivotable arm. Pump (155) is an auxiliary pump selectively connectible to the piston and cylinder devices (31, 32, 61, 62) so that each device may be activated to pivot a respective arm (23,24,53,54) relative to the frame independently of the supply of hydraulic fluid to the wheel motors (126,128,129,127) and thus vary the disposition of the wheel (20, 21, 50, 51) mounted on the arm relative to the frame. The tractor may also incorporate a load-carrying platform (91) mounted on an extensible portion (45,46) of the frame. The frame may have front and rear parts (2, 3) articulated together for relative rotation about substantially vertical (5) and substantially horizontal (6) axes.
Inventors
- 👤 John C.S. Wilkinson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 14:59
CPC Classifications
B; B62; B62D; B62D49/00; B62D49/06; B62D53/00; B62D53/02; B62D53/021
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
204 words
A tractor (1) having a frame (2,3) and three or more wheels (20,21,50,51), each wheel being driven by a hydrostatic motor (126,128,129,127) and being mounted on an arm (23,24,53,54) which is pivotable relative to the frame, the tractor having a power unit (111) driving two or more pumps (113,114,115,145,155) for supplying hydraulic fluid under pressure, at least one (113) of said pumps being a drive pump for supplying hydraulic fluid under pressure to two (126,127) of said wheel motors in parallel, a hydraulic piston and cylinder device (31,32,61,62) being mounted between the frame and each of said pivotable arms (23,24,53,54) on which the wheels are mounted, one of the cylinder and piston of said device being associated with the frame and the other of the cylinder and piston of the device being associated with said pivotable arm, and another (155) of said pumps being an auxiliary pump selectively connectible to said piston and cylinder devices (31,32,61,62) so that each said device may be activated to pivot a respective said arm (23,24,53,54) relative to the frame independently of the supply of hydraulic fluid to said wheel motors (126,128,129,127) and thus vary the disposition of the wheel (20,21,50,51) mounted on said arm relative to the frame.
Claim 2
Dependent Claim
204 words
A tractor (1) having a frame (2,3) and three or more wheels (20,21,50,51), each wheel being driven by a hydrostatic motor (126,128,129,127) and being mounted on an arm (23,24,53,54) which is pivotable relative to the frame, the tractor having a power unit (111) driving two or more pumps (113,114,115,145,155) for supplying hydraulic fluid under pressure, at least one (113) of said pumps being a drive pump for supplying hydraulic fluid under pressure to two (126,127) of said wheel motors in parallel, a hydraulic piston and cylinder device (31,32,61,62) being mounted between the frame and each of said pivotable arms (23,24,53,54) on which the wheels are mounted, one of the cylinder and piston of said device being associated with the frame and the other of the cylinder and piston of the device being associated with said pivotable arm, and another (155) of said pumps being an auxiliary pump selectively connectible to said piston and cylinder devices (31,32,61,62) so that each said device may be activated to pivot a respective said arm (23,24,53,54) relative to the frame independently of the supply of hydraulic fluid to said wheel motors (126,128,129,127) and thus vary the disposition of the wheel (20,21,50,51) mounted on said arm relative to the frame.
Claim 3
Dependent Claim
52 words
A tractor according to claim 1, wherein a valve (136) is provided for directing hydraulic fluid from a high pressure supply line supplying said two motors (126,127) in parallel to a reservoir (138) for hydraulic fluid in the event of a speed difference between the motors or an excess hydraulic fluid pressure.
Claim 4
Dependent Claim
77 words
A tractor according to claim 1 or claim 2, having four wheels (20,21,50,51) and two drive pumps (113,114), each drive pump (113,114) supplying hydraulic fluid to two - (126,127;128,129) of said wheel motors in parallel, one of the two wheels driven by said two wheel motors in parallel being a front wheel (20,21) considered relative to the normal direction of travel of the tractor and the other (50,51) of said wheels similarly considered being a rear wheel.
Claim 5
Dependent Claim
41 words
A tractor according to any preceding claim, wherein valve means (156) are provided for simultaneously connecting said auxiliary pump (155) to all of said piston and cylinder devices (31,32,61,62) so that all of said arms are pivoted at the same time.
Claim 6
Dependent Claim
55 words
A tractor according to any preceding claim, comprising load-carrying means (91) delimiting at least in part a load-accommodating space or volume, wherein the load-carrying means is mounted on an extensible frame portion (45,46) which is displaceable relative to the remainder of the frame so that said load-accommodating space or volume may be varied in size.
Claim 7
Dependent Claim
94 words
A tractor according to any preceding claim, wherein each pivotable arm (23,24,53,54) is mounted on a mounting member (25,26,55,56) displaceable relative to the frame in a direction substantially parallel to the axis of rotation of the wheel mounted on said arm, and means (27,28,57,58) are provided for locating the mounting member in a selected one of a plurality of positions relative to the frame and substantially locking the member in said position relative to the frame so that when thus locked it cannot be further displaced relative to the frame without releasing said means.
Claim 8
Dependent Claim
87 words
A tractor according to any preceding claim, wherein each of the pivotable arms (23,24,53,54) extends from the frame in the same direction relative to the direction of travel of the tractor and the dimension between the point (35,36,65,66) of pivoting of the arm relative to the frame and the axis of the wheel (20,21,50,51) mounted on said arm is the same for each arm, so that the tractor wheelbase (A) may remain substantially constant when each arm is in the same pivoted disposition relative to the frame.
Claim 9
Dependent Claim
135 words
A tractor according to any preceding claim, wherein the frame has a front part (2) and a rear part (3) and is articulated for relative rotation between the front frame part and the rear frame part about a substantially vertical axis (5), at least one hydraulic piston and cylinder device (99,100) being mounted between said front and rear frame parts, the cylinder portion of said device being associated with one (2) of said frame parts and the piston portion of the device being associated with the other frame part (3) so that said device may be activated to pivot one frame part relative to the other and constrain the wheel or wheels (20,21) of the one frame part (2) to follow an instantaneous path differing from that or those (50,51) of the other frame part.
Claim 10
Dependent Claim
49 words
A tractor according to claim 8, wherein said front frame part (2) and said rear frame part (3) are also relatively rotatable about a substantially horizontal axis (4) extending substantially in the direction of travel of the tractor, so that relative twisting of the frame parts may take place.
Claim 11
Dependent Claim
48 words
A tractor according to any preceding claim, wherein each wheel (20,21,50,51) has braking means and individual control means are provided for each said braking means so that the braking force applied to each wheel may be controlled independently of the braking forces applied to others of the wheels.
References Cited (Backward Citations)
No citation records indexed.
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