ALL-WHEEL STEERING SYSTEM

• US 3,572,458 A
• Filed: 12/10/1968
• Issued: 03/30/1971
• Est. Priority Date: 12/10/1968
• Status: Expired due to Term

• Current Assignee: Tax Hans
• Original Assignee: Tax Hans
• Inventors: TAX HANS
• Application Number:
  US04/782,671
• Time in Patent Office: 840 Days
• US Class Current: 180/411
• CPC Class Codes: B62D 7/02 for pivoted bogies

Abstract

A system for individually steering all wheels of a heavy vehicle in which the wheel supports are individually turned by servomotors. The operating signals of respective cam controlled servo transmitters and signals from position indicators are combined to produce error signals which are fed to the servomotors. The cams allow for the different turning angle required for each wheel and may be replaced by other cams shaped for parallel turning of all wheels. If the track width of the vehicle is variable, the individual cams are replaced by cam drums which are shifted axially in response to changes in track width and are shaped to compensate for the required changes in the turning angle with the track width.

Claims

1. In a steering system for a vehicle having a body, a plurality of supports mounted on said body for angular displacement about respective, normally vertically exteNding axes, a wheel rotatably mounted on each support, and turning means on said body for individually turning said supports about the axes thereof, the improvement in the turning means which comprises:

a. a plurality of servomotor means interposed between said body and respective supports for changing the angular positions of the associated supports relative to said axes, two of said supports being movable on said body toward and away from each other transversely of the normal direction of movement of said vehicle;

b. a plurality of servo transmitter means connected to said servomotor means for transmitting to the connected servomotor means respective operating a signals representative of desired angular positions of the associated supports;

c. joint actuating means operatively connected to said plurality of servo transmitter means for simultaneously actuating the same and for thereby simultaneously turning said supports through respective turning angles; and

d. modifying means for modifying the magnitude of said turning angles in response to the spacing of said two supports.

2. In a system as set forth in claim 1, each of said servomotor means including position indicating means connected to the associated support for producing an indicating signal representative of the actual angular position of said support, comparator means connected to said position indicating means and to the associated servo transmitter means for receiving said indicating signal and said operating signal, and for emitting an error signal representative of a difference between the angular positions respectively represented by said operating and indicating signals, and turning motor means connected to said support and to said comparator means and responsive to said error signal to turn said support in a direction to reduce the magnitude of said error signal.

3. In a system as set forth in claim 1, said actuating means including a movable control member and responding to movement of said control member for actuating said servo transmitter means.

4. In a system as set forth in claim 3, said actuating means including shifting means for varying the relationship of the magnitudes of said turning angles in response to said predetermined movement of said control member.

5. In a system as set forth in claim 3, shifting means for shifting said actuating means between a first condition in which said turning angles are equal, and a second condition in which said turning angles are different.

6. In a system as set forth in claim 1, an electrical circuit operatively interposed between each servomotor and the associated servo transmitter, and constituting the sole connection between said servomotor and said servo transmitter.

7. In a steering system for a vehicle having a body, four extension arms pivoted to said body for movement about respective vertically extending pivot axes, each arm having a terminal portion remote from the associated pivot axis, an axle assembly mounted on each terminal portion for angular movement about a vertically extending turning axis, said axle assemblies moving toward and away from each other between a plurality of relative positions during said movement of said arms, and a wheel mounted on each axle assembly for rotation about a horizontally extending axis of rotation and for rolling engagement with a surface for thereby supporting said vehicle on said surface, and turning means for turning said axle assemblies about the respective turning axes, the improvement which comprises:

a. pivot means securing said arms to said body for free swinging movement about said pivot axes respectively;

b. a turning motor on each extension arm operatively connected to the corresponding axle assembly for turning the latter; and

c. single operating means connected to said turning motors for simultaneously operating a plurality of said turning motors in a direction to cause said swinging movement of the arms associated with said plurality of motors when the wheels mounted on the associated axle assemblies are in rolling engagement with said surface, whereby said associated axle assemblies are moved between said relative positions.

8. In a system as set forth in claim 7, said plurality of motors including the turning motor on each of said four arms.

9. In a system as set forth in claim 7, said operating means including generating means for generating a plurality of operating signals, transmitting means for transmitting said operating signals to said plurality of motors respectively and for operating the motors in response to the transmitted signals, and control means for controlling said generating means, said control means including a single movable control member, and means operatively connecting said control member to said generating means for actuating the same in response to the movement of said control member.

10. In a steering system for a vehicle having a body, four extension arms pivoted to said body for movement about respective vertically extending pivot axes, each arm having a terminal portion remote from the associated pivot axis, an axle assembly mounted on each terminal portion for angular movement about a vertically extending turning axis, said axle assemblies moving toward and away from each other between a plurality of relative positions during said movement of said arms, and a wheel mounted on each axle assembly for rotation about a horizontally extending axis of rotation and for rolling engagement with a surface for thereby supporting said vehicle on said surface, and turning means for turning said axle assemblies about the respective turning axes, the improvement which comprises:

a. a turning motor on each extension arm operatively connected to the corresponding axle assembly for turning the latter; and

b. operating means connected to said turning motors and responsive to said relative positions of said axle assemblies for operating the motors in a manner that said axes of rotation intersect a common vertical line after said turning in each of said relative positions.

11. In a system as set forth in claim 10, said operating means including sensing means for sensing the relative position of said axle assemblies, generating means for generating a plurality of operating signals, transmitting means for transmitting said operating signals to said motors respectively and for operating said motors in response to the transmitted signals, control means including a single movable control member, means operatively connecting said control member to said generating means for actuating the same in response to the movement of said control member, and modifying means for modifying said operating signals in response to the sensed relative position.