Motor-driven cart

• US 5,657,828 A
• Filed: 07/27/1995
• Issued: 08/19/1997
• Est. Priority Date: 07/29/1994
• Status: Expired due to Fees

• Current Assignee: Shinwa Denshi Kabushiki Kaisha
• Original Assignee: Shinwa Denshi Kabushiki Kaisha
• Inventors: Nagamachi, Sakae
• Primary Examiner(s): Hurley, Kevin
• Application Number:
  US08/507,910
• Time in Patent Office: 754 Days
• Field of Search: 180/19.1, 180/19.3, 180/6.48, 180/6.5, 180/332, 180/333, 180/167, 180/168
• US Class Current: 180/19.3
• CPC Class Codes: B60L 2200/30 Trolleys
• CPC Class Codes: B60L 50/52 characterised by DC-motors
• CPC Class Codes: B62B 5/0073 Measuring a force
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A motor-driven cart includes a manned/unmanned operation change-over switch, first and second electric motors for driving the cart, a handle lever provided to a main body of the cart to be swung to a predetermined angle with respect to a left, right, forward or backward direction, and a device for generating electric signal for steering and for speed control in response to a swing operation of the handle lever. When an operator changes the manned/unmanned operation change-over switch to its manned operation side and the handle lever is placed in its neutral zone, the motors are put in their stopped state. When the operator manipulates the handle lever in the left, right, forward or backward direction to a position outside the neutral zone, the forward or reverse rotational speeds of the first and second motors are increased in proportion to the extent of the swing operation to turn the cart to the left or right direction or to perform the forward or backward speed control. When the operator'"'"'s hand is released from the handle lever, this causes the lever to be automatically returned to the neutral zone nearly in the middle of pivotal center by a restoring force of four spring members.

Claims

1. A motor-driven cart comprising:

a first and a second motor for driving wheels of said cart;

a handle lever disposed on a main body of said cart so as to be capable of being swung by a predetermined angle in selected one of left, right, forward, and backward, and obliquely right and left in both forward and backward directions;

means for generating electric signals for steering and for controlling the speeds of said first and second motors in response to an extent of swing motion of said handle lever, whereby said first and second motors are put in their stopped state when said handle lever is in its neutral zone, while when said handle lever is swung in selected one of the left, right, forward, backward and any other desired horizontal directions outside said neutral zone, said first and second motors are increased in their rotational speeds in a forward or reverse direction in response to the direction and extent of swing motion applied to said handle lever so as to carry out speed control of said cart in the selected one of left, right, forward, backward and any other desired horizontal directions;

a guide sensor;

a sensor for detecting a forward obstacle; and

a manned/unmanned operation change-over switch, whereby when an operator changes said manned/unmanned operation change-over switch to its unmanned operation side and puts said motor-driven cart onto a previously-laid route line, said cart can be driven at a predetermined speed along said previously laid route line, and when said forward obstacle sensor detects presence of such an obstacle as another motor-driven cart stopping forward of said route line, said motor-driven cart is stopped at a place spaced apart from said obstacle at a predetermined distance, while when the operator changes said manned/unmanned change-over switch to its manned operation side, said motor-driven cart can run to an arbitrary place away from said route line in accordance with an operator'"'"'s swing manipulation of said handle lever.

2. A motor-driven cart as set forth in claim 1, wherein said handle lever is equipped with a spring for returning said handle lever to its neutral zone by its restoring force, whereby when an external force as a pulling or pushing action of an operator is exerted to said handle lever, said handle lever is swung in a positive or negative direction against the restoring force of said spring, while when no such external force is applied to said handle lever, said handle lever is kept in said neutral zone nearly in the middle of the rotation of said handle lever under the influence of the restoring force of said spring.

3. A motor-driven cart as set forth in claim 1, wherein said handle lever is supported by four springs arranged to surround said handle lever for returning said handle lever to its neutral zone by their restoring forces, whereby when said handle lever is swung by an external force to one of the left, right, forward, backward and any other desired horizontal directions, said handle lever is swung in a positive or negative direction against the restoring forces of said springs, while when no such external force is applied to said handle lever, said handle lever is returned to said neutral zone nearly in the middle of the swing motion of said lever by the restoring forces of said springs.

4. A motor-driven cart as set forth in claim 1, wherein switching of said motors between the forward and reverse rotations is carried out by formation of a forward or reverse circuit for the motors effected by actuation of forward and backward elements in response to positive or negative swing movement of said handle lever exceeding said neutral zone.

5. A motor-driven cart as set forth in claim 1, wherein said handle lever is mechanically and electrically coupled to variable resistors, whereby resistive values of said variable resistors are increased/decreased in response to the extent of swing motion in a positive/negative direction of said handle lever so that said electrical signals are generated as positive/negative signals.

6. A motor-driven cart as set forth in claim 5, wherein said means for generating the electric signals for steering and for speed control in response to a swing movement of said handle lever includes a joystick mechanism for actuating said variable resistors in response to the direction and extent of force of manipulation of said handle lever, a steering control circuit actuated by a signal from said joystick mechanism or from said guide sensor, and a motor control signal generator, whereby said electric signals are generated from said joystick mechanism, said steering control circuit, and said motor control signal generator and further from said forward obstacle sensor if occasion demands.

7. A motor-driven cart comprising;

a plurality of electric motors for driving wheels of said cart;

means for generating an electric signal in operative response to an extent of swing motion imparted to a handle lever provided to a main body of said cart so as to be swingably operative at least in forward and backward directions, whereby when said handle lever is placed in a neutral zone, said motors are put in their stopped state, while when said handle lever is swung to a position outside said neutral zone, said motors are increased in their rotational speeds in a forward or reverse direction in response to the direction and extent of swing motion applied to said handle lever;

a guide sensor;

a sensor for detecting a forward obstacle; and

a manned/unmanned operation change-over switch, whereby when an operator changes said manned/unmanned operation change-over switch to its unmanned operation side and puts said motor-driven cart onto a previously-laid route line, said cart can be driven at a predetermined speed along said previously laid route line, and when said forward obstacle sensor detects presence of such an obstacle as another motor-driven cart stopping forward of said route line, said motor-driven cart is stopped at a place spaced apart from said obstacle at a predetermined distance, while when the operator changes said manned/unmanned change-over switch to its manned operation side, said motor-driven cart can run to an arbitrary place away from said route line in accordance with an operator'"'"'s swing manipulation of said handle lower.

8. A motor-driven cart as set forth in claim 7, wherein said handle lever is equipped with a spring for returning said handle lever to its neutral zone by its restoring force, whereby when an external force as a pulling or pushing action of an operator is exerted to said handle lever, said handle lever is swung in a positive or negative direction against the restoring force of said spring, while when no such external force is applied to said handle lever, said handle lever is kept in said neutral zone nearly in the middle of the rotation of said handle lever under the influence of the restoring force of said spring.

9. A motor-driven cart as set forth in claim 7, wherein switching of said motors between the forward and reverse rotations is carried out by formation of a forward or reverse circuit for the motors effected by actuation of forward and backward elements in response to positive or negative swing movement of said handle lever exceeding said neutral zone.

10. A motor-driven cart as set forth in claim 7, wherein said handle lever is mechanically and electrically coupled to variable resistors, whereby resistive values of said variable resistors are increased/decreased in response to the extent of swing motion in a positive/negative direction of said handle lever so that said electrical signals are generated as positive/negative signals.