Pallet counter for lift truck

• US 7,992,686 B2
• Filed: 07/10/2008
• Issued: 08/09/2011
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: The Raymond Corporation (Toyota Motor Corporation)
• Original Assignee: The Raymond Corporation (Toyota Motor Corporation)
• Inventors: McCabe, Paul Patrick
• Primary Examiner(s): SALATA, ANTHONY J
• Application Number:
  US12/170,622
• Publication Number:
  US 20100006377A1
• Time in Patent Office: 1,125 Days
• Field of Search: 187222-224, 187/233, 187/277, 187391-394, 701/23, 701/29, 701/50, 414/592, 414610-613, 414/675, 212/282, 212/283, 340/568.1, 3405721-5724, 177/139
• US Class Current: 187/224
• CPC Class Codes: B66F 9/07545 Overhead guards
• CPC Class Codes: B66F 9/0755 Position control; Position detectors
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management

Abstract

A method for counting the pallets or loads moved by a lift truck using internal sensors is disclosed. The lift truck includes a weight sensor for weighing a load, a height sensor, for measuring a height of the forks, and a distance sensor for determining whether the vehicle has moved. When the data from each of these sensors exceeds a corresponding minimum value, a vehicle control system increments a pallet counter. A count of the number of pallets moved is therefore maintained without the need for tracking specific pallets of for adding expensive components and devices.

Claims

1. A lift truck, comprising:

a power unit;

a fork moveably coupled to the power unit;

a weight sensor coupled to the fork for producing a weight control signal indicative of a weight of a load provided on the fork;

a lift motor coupled to the fork for raising and lowering the fork;

a height sensor coupled to the fork for producing a height control signal indicative of a height of the fork;

a wheel coupled to the power unit;

a distance sensor coupled to the wheel for providing a distance control signal indicative of a distance traveled; and

a vehicle control system, the vehicle control system in communication with the weight sensor, the height sensor, and the distance sensor, wherein the vehicle control system is programmed to receive the weight control signal, the height control signal, and the distance control signal, and is programmed to determine whether a pallet has been moved based on the weight control signal, the height control signal, and the distance control signal, and to increment a pallet count.

2. The lift truck as defined in claim 1, wherein the vehicle control system is further programmed to compare the weight control signal, the height control signal, and the distance control signal to a minimum load weight, a minimum travel distance, and a minimum load height, respectively, and to increment the pallet count when the weight control signal, the height control signal, and the distance control signal exceed the corresponding minimum load weight, minimum travel distance, and minimum load height.

3. The lift truck as defined in claim 1, wherein the vehicle control system is further programmed to monitor a clock signal and to calculate a time period associated with the pallet count.

4. The lift truck as defined in claim 1, wherein the vehicle control system is further programmed to calculate a number of pallets moved for a predetermined period as a function of the pallet count and the time period.

5. The lift truck as defined in claim 4, wherein the vehicle control system is further programmed to calculate an average number of pallets moved over a predetermined period of time as a function of the pallet count and the time period.

6. The lift truck as defined in claim 1, further comprising a scanning device coupled to the vehicle control system, the scanning device being programmed to read an identifier associated with a pallet to be moved.

7. The lift truck as defined in claim 6, wherein the identifier is at least one of an active data tag and a passive data tag.

8. The lift truck as defined in claim 6, wherein the data tag is at least one of an RFID tag, a RuBee tag, or a barcode symbol.

9. The lift truck of claim 1, wherein the vehicle control system is further programmed to compare the identifier to a stored list to identify the load.

10. The lift truck of claim 1, further comprising a user input in communication with the vehicle control system, wherein the vehicle control system is further programmed to receive the minimum load weight, the minimum travel distance, and the minimum load height from the operator, and to store the minimum load weight, the minimum travel distance, and the minimum load height in memory.

11. The lift truck of claim 1, wherein the weight sensor is at least one of a load cell, a strain gauge, and a pressure sensor.

12. The lift truck of claim 1, wherein the height sensor is at least one of an encoder, a flow sensor, and a light beam.

13. The lift truck of claim 1, further comprising a display in communication with the vehicle control system, wherein the vehicle control system is programmed to selectively provide the pallet count on the display.

14. The lift truck of claim 1, further comprising at least one communications port coupled to the vehicle control system, the vehicle control system being further programmed to selectively communicate the pallet count and the time period through the communications port.

15. The lift truck of claim 1, further comprising a scanner in communication with the vehicle control system for scanning an identifier associated with the pallet, wherein the vehicle control system is programmed to compare the identifier against a listing of loads to be moved, and to increment the pallet counter only when the identifier matches the listing of loads.

16. The lift truck of claim 1, wherein the controller calculates the distance as a length of travel of the vehicle.

17. The lift truck of claim 1, wherein the controller calculates the distance as a function of traction motor activation and time.

18. A method for determining an efficiency of an operator driving a lift truck having a fork for moving pallets, the method comprising the following steps:

determining a weight of a load on the fork;

determining a height of the fork;

determining a distance traveled by the lift truck;

comparing each of the weight of the load, the height of the fork, and the distance traveled by the lift truck to a minimum weight, height, and distance, respectively; and

incrementing a pallet counter when the weight of the load, the height of the fork, and the distance traveled exceed the corresponding minimum weight, height, and distance, respectively.

19. The method as recited in claim 18, further comprising the step of calculating a time period, and correlating the time period to the pallet count for the time period.

20. The method as recited in claim 18, further comprising the step of selectively providing at least one of the pallet count, the time period, and a pallet count as a function of the time period to a user.

21. The method as recited in claim 18, further comprising the step of identifying the pallet, comparing the identity of the pallet to a listing of loads to be moved, and incrementing the load count only if the load is part of the listing.

22. The method as recited in claim 18, further comprising the step of determining when the weight of the load on the truck falls below the minimum level indicating that the load has been removed, and incrementing the pallet count when the load has been removed.

23. The method as recited in claim 18, wherein the step of determining a distance traveled comprises calculating a time period during which a traction motor is active.

24. The method as recited in claim 18, wherein the step of determining a distance traveled comprises calculating a length of travel by the lift truck.