Apparatus for controllably positioning a lift mast assembly of a work vehicle

• US 4,869,635 A
• Filed: 03/31/1988
• Issued: 09/26/1989
• Est. Priority Date: 03/31/1988
• Status: Expired due to Fees

• Current Assignee: FMC Corporation
• Original Assignee: Caterpillar Industrial Inc (Caterpillar Incorporated)
• Inventors: Krahn, Darren L.
• Primary Examiner(s): Kashnikow, Andres
• Assistant Examiner(s): Newholm, Timothy
• Application Number:
  US07/176,018
• Time in Patent Office: 544 Days
• Field of Search: 414/117, 414/273, 414/274, 414/730, 414/275, 414/786, 414/667, 901/46, 901/47, 294/907, 180/274, 280/6 R, 280/6 H, 280/761
• US Class Current: 414/274
• CPC Class Codes: B66F 9/063 Automatically guided
• CPC Class Codes: B66F 9/0755 Position control; Position detectors

Abstract

An apparatus and method for controllably moving the carriage assembly of a automated load handling vehicle vertically and horizontally. The carriage assembly includes load detecting sensors which detect the opening in the load during movement of the carriage assembly. Once the opening is located, a controller positions the carriage assembly at vertical and horizontal target positions, and moves the carriage assembly into the opening.

Claims

1. An apparatus for controllably moving a lift mast assembly of a work vehicle to a preselected position relative to an opening in a load, the lift mast assembly having a lift mast and a carriage assembly having a side shiftable load engaging implement, said carriage assembly being mounted on and elevationally moveable along the lift mast, said load engaging implement having first and second end portions, said second end portion extending from the carriage assembly, the apparatus comprising:

sensor means for delivering electromagnetic radiation in a direction generally away from the work implement toward the load, detecting reflected electromagnetic radiation, and delivering a signal in response to detecting the reflected electromagnetic radiation, said sensor means being connected to the second end portion of said work implement;

means for sensing the vertical height of the carriage assembly;

means for controllably moving the carriage assembly in first and second vertical directions;

means for storing the vertical height of the carriage assembly as a first vertical variable in response to receiving a first vertical signal from the sensor means and storing the vertical height of the carriage assembly as a second vertical variable in response to receiving a second vertical signal;

means for sensing the horizontal position of the carriage assembly;

means for controllably moving the carriage assembly in first and second horizontal directions, said storing means storing a first horizontal position of the carriage assembly as a first horizontal variable in response to receiving a first horizontal signal and storing a second horizontal position of the carriage assembly as a second horizontal variable in response to receiving a second horizontal signal, said calculating means calculating a horizontal target position as a function of the first and second horizontal variables, and said horizontal and vertical carriage moving means moving the carriage assembly to the vertical and horizontal target positions;

means for calculating one of a vertical and horizontal dimension of the load opening as a function of the respective vertical and horizontal first and second variables, comparing said one calculated dimension to a respective one of preselected vertical and horizontal dimension, and delivering a terminating signal in response to the one preselected dimension being greater than the one calculated dimension; and

means for moving the load engaging implement into the load opening; and

means for preventing movement of the load engaging implement into the load opening in response to receiving the terminating signal.

2. The apparatus, as set forth in claim 1, including:

means for calculating the other of the horizontal and vertical dimension of the load opening as a function of the respective horizontal and vertical first and second variables, comparing the other calculated dimension to the other preselected horizontal and vertical dimension, and delivering a terminating signal in response to the other preselected dimension being greater than the other calculated dimension.

3. An automatic fork positioning apparatus for controllably moving a lift mast assembly of a forklift to a preselected position relative to an opening in a pallet, the lift mast assembly having a lift mast and a carriage assembly having a side shiftable load engaging implement, said carriage assembly being mounted on and elevationally moveable along the lift mast, said load engaging implement having a fork having first and second end portions, said second end portion extending from the carriage assembly, the apparatus comprising;

sensor means for delivering electromagnetic radiation in a direction generally away from the work implement toward the load, detecting reflected electromagnetic radiation, and delivering a signal in response to detecting the reflected electromagnetic radiation, said sensor means being connected to the second end portion of said fork;

means for sensing the vertical height of the carriage assembly;

means for controllably moving the carriage assembly in first and second vertical directions;

means for storing the vertical height of the carriage assembly as a first vertical variable in response to receiving a first vertical signal from the sensor means and storing the vertical height of the carriage assembly as a second vertical variable in response to receiving a second vertical signal from the sensor means;

means for sensing the horizontal position of the carriage assembly;

means for controllably moving the carriage assembly in first and second horizontal directions, said storing means storing a first horizontal position of the carriage assembly as a first horizontal variable in response to receiving a first horizontal signal and storing a second horizontal position of the carriage assembly as a second horizontal variable in response to receiving a second horizontal signal, said calculating means calculating a horizontal target position as a function of the first and second horizontal variables, and said horizontal and vertical carriage moving means moving the carriage assembly to the vertical and horizontal positions;

means for calculating one of a vertical and horizontal dimension of the load opening as a function of the respective vertical and horizontal first and second variables, comparing the one calculated dimension to a respective one of preselected vertical and horizontal dimension, and delivering a terminating signal in response to the one preselected dimension being greater than the one calculated dimension;

means for moving the fork into the load opening; and

means for preventing movement of the fork into the load opening in response to receiving the terminating signal.

4. The apparatus, as set forth in claim 3, including:

means for calculating the other of the horizontal and vertical dimension of the load opening as a function of the respective horizontal and vertical first and second variables, comparing said other calculated dimension to a respective preselected horizontal and vertical dimension, and delivering a terminating signal in response to the other preselected dimension being greater than the other calculated dimension.

5. A method for controllably moving a lift mast assembly of a work vehicle to a preselected position relative to an opening in a load defined by top and bottom and right and left edges, said lift mast assembly having a lift mast and a side shiftable carriage assembly mounted on and elevationally moveable along the lift mast, the method comprising the steps of:

sensing the position of the bottom edge of the load opening;

sensing the position of a top edge of the load opening;

calculating a vertical target position as a function of the top and bottom edge positions;

sensing a position of the left edge of the load opening;

sensing the position of the right edge of the load opening;

calculating a horizontal target position as a function of the left and right edge positions;

moving the carriage assembly to the vertical and horizontal target positions;

calculating the vertical dimension of the load opening;

comparing the calculated vertical dimension to a preselected vertical dimension; and

maintaining the carriage assembly from movement into the load opening in response to the calculated vertical dimension being less than the preselected vertical dimension.

6. The method, as set forth in claim 5 including the steps of:

calculating the horizontal dimension of the load opening;

comparing the calculated horizontal dimension to a preselected horizontal dimension; and

maintaining the carriage assembly from movement into the load opening in response to the calculated horizontal dimension being less than the preselected horizontal dimension.

7. A method for controllably moving a lift mast assembly of a work vehicle to a preselected position relative to an opening in a load defined by top and bottom and right and left edges, said lift mast assembly having a lift mast and a side shiftable carriage assembly mounted on and elevationally moveable along the lift mast, the method comprising the steps of:

sensing the position of the bottom edge of the load opening;

sensing the position of a top edge of the load opening;

calculating a vertical target position as a function of the top and bottom edge positions;

sensing a position of the left edge of the load opening;

sensing the position of the right edge of the load opening;

calculating a horizontal target position as a function of the left and right edge positions;

moving the carriage assembly to the vertical and horizontal target positions;

sensing the position of the top edge;

sensing the position of the bottom edge;

calculating a vertical target position; and

moving the carriage assembly into the load opening.

8. A method for controllably moving a lift mast assembly of a work vehicle to a preselected position relative to an opening in a load defined by top and bottom and right and left edges, said lift mast assembly having a lift mast and a side shiftable carriage assembly mounted on and elevationally moveable along the lift mast, the method comprising the steps of:

sensing the position of the bottom edge of the load opening;

sensing the position of a top edge of the load opening;

calculating a vertical target position as a function of the top and bottom edge positions;

sensing a position of the left edge of the load opening;

sensing the position of the right edge of the load opening;

calculating a horizontal target position as a function of the left and right edge positions;

moving the carriage assembly to the vertical and horizontal target positions;

moving the carriage assembly into the load opening; and

repeating the steps of;

sensing the position of the bottom edge of the load opening;

sensing the position of the top edge of the load opening; and

calculating a vertical target position as a function of the top and bottom edge positions in response to failure to sense one of the top and bottom edges.