Power-assisted cart retriever with attenuated power output

• US 20050098364A1
• Filed: 09/23/2004
• Published: 05/12/2005
• Est. Priority Date: 09/23/2003
• Status: Active Grant

• Current Assignee: Dane Technologies Incorporated
• Original Assignee: Dane Technologies Incorporated
• Inventors: Johnson, Daniel T., Holtan, Paul D., Wiff, James W.
• Granted Patent: US 7,389,836 B2
• Time in Patent Office: Days
• US Class Current: 180/65.1
• CPC Class Codes: B62B 3/1404 Means for facilitating stowing or transporting of the trolleys; Antitheft arrangements B62B5/0423 takes precedence
• CPC Class Codes: B62B 5/0069 Control
• CPC Class Codes: B62B 5/0076 Remotely controlled
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

The present invention is a motorized shopping cart retriever that includes a controller that attenuates the power provided to the drive system of the retriever to prevent the retriever from being utilized to move an excessively heavy load of shopping carts. By preventing the retriever and carts from being subjected to overloaded conditions, the operational lives of the retriever and carts are maximized. The retriever is also provided with a burst mode that allows the power provided to the drive system to rapidly increase past the normal attenuated level for a brief period of time in order to reduce the time required to accelerate a retriever loaded with carts to a terminal velocity.

Claims

1. A shopping cart retriever comprising:

an electric motor;

a drive system powered by the electric motor;

a controller adapted to provide power to the electric motor and including a first power limit and a second power limit; and

a throttle control in communication with the controller,

wherein the first power limit is the controller'"'"'s normal power limit that results when the controller self-limits its maximum power output through a sensing feature of the controller that exists to prevent damage to the controller, and

wherein the second power limit is selectable and limits the control'"'"'s maximum power output to a level that is less than that of the first power limit.

2. The retriever of claim 1, wherein the second power limit is selected to provide a power output level that optimizes the operational life of a component of the retriever or of a shopping cart.

3. The retrieve of claim 1, wherein the second power limit is selected to provide a power output level that prevents the retriever from being subjected to an overload condition.

4. The retriever of claim 1, wherein the controller further includes a burst mode that allows the control'"'"'s maximum power output to exceed the second power limit for a limited time before again becoming subject to the second power limit.

5. The retriever of claim 4, wherein the burst mode includes a third power limit that is selectable and limits the control'"'"'s maximum power output to a level that is less than that of the first power limit and greater than that of the second power limit.

6. The retriever of claim 1, wherein the second power limit attenuates current.

7. The retriever of claim 1, wherein the second power limit attenuates voltage.

8. The retriever of claim 1, wherein the sensing feature is a temperature sensing feature that senses a temperature of the controller.

9. The retriever of claim 1, wherein the sensing feature is a current level sensing feature that senses a current level passing through the controller.

10. The retriever of claim 1, wherein the controller is an analog controller.

11. The retriever of claim 1, wherein the controller is a digital controller.

12. The retriever of claim 1, wherein the electric motor is a brush DC motor.

13. The retriever of claim 12, wherein the brush DC motor is a series wound DC motor.

14. The retriever of claim 12, wherein the brush DC motor is a separately excited DC motor.

15. The retriever of claim 1, wherein the electric motor is a brushless DC motor.

16. The retriever of claim 1, wherein the electric motor is an AC motor.

17. A method of operating a shopping cart retriever, the method comprising:

placing a controller in electrical communication with an electric motor adapted to power a drive system of the retriever;

placing a throttle control in communication with the controller;

setting the controller at a first power limit that is less than a second power limit, wherein the second power limit is the controller'"'"'s normal power limit that results when the controller self-limits its maximum power output through a sensing feature of the controller that exists to prevent damage to the controller; and

moving at least one shopping cart with the cart retriever by sending power to the electrical motor from the controller at a level no greater than the first power limit although the throttle control is set at 100 percent full throttle.

18. The method of claim 17, wherein the first power limit is set to provide a power output level that optimizes the operational life of a component of the retriever or of a shopping cart.

19. The method of claim 17, wherein the first power limit is set to provide a power output level that prevents the retriever from being subjected to an overload condition.

20. The method of claim 17, wherein the first power limit is achieved by attenuating a current or a voltage provided to the electrical motor by the controller.

21. A method of operating a shopping cart retriever, the method comprising:

placing a controller in electrical communication with an electric motor adapted to power a drive system of the retriever;

placing a throttle control in communication with the controller;

setting the controller at a first power limit that is less than a second power limit, wherein the second power limit is the controller'"'"'s normal power limit that results when the controller self-limits its maximum power output through a sensing feature of the controller that exists to prevent damage to the controller;

attaching the retriever to at least one shopping cart; and

activating a burst mode to accelerate the retriever and the at least one shopping cart from a complete stop to a terminal velocity, wherein power provided to the motor from the controller rapidly increases to a burst limit and then rapidly decreases from the burst limit to reach a level approximate the first limit when the retriever approaches the terminal velocity, wherein the burst limit is less than the second power limit and greater than the first power limit.

22. The method of claim 21, wherein the first power limit is set to provide a power output level that optimizes the operational life of a component of the retriever or of a shopping cart.

23. The method of claim 21, wherein the first power limit is set to provide a power output level that prevents the retriever from being subjected to an overload condition.

24. The method of claim 21, wherein the first power limit is achieved by attenuating a current or a voltage provided to the electrical motor by the controller.