Pallet truck with weighing scale

• US 4,666,004 A
• Filed: 05/01/1986
• Issued: 05/19/1987
• Est. Priority Date: 05/01/1986
• Status: Expired due to Term

• Current Assignee: Tedea-Huntleigh Inc. (Vishay Intertechnology Incorporated)
• Original Assignee: Pallet Truck Scale Corporation
• Inventors: Raz, Matti
• Primary Examiner(s): Miller, Jr., George H.
• Application Number:
  US06/858,586
• Time in Patent Office: 383 Days
• Field of Search: 177/139, 177/140, 177/146
• US Class Current: 177/139
• CPC Class Codes: B62B 2203/50 comprising weighing means
• CPC Class Codes: G01G 19/083 lift truck scale

Abstract

A pallet truck with a fork member movable in an up-and-down manner is provided with a plurality of load cells on the tines of the fork member for weighing loads carried by the pallet truck. Each load cell is mounted by a tine of the fork member, over which tine is floatingly mounted an elongated floating member extending substantially along the entire length of the respective tine member. Each floating member is supported by at least one ball bearing operatively associated with at least one load cells on the tine. A crosspiece is provided interconnecting the ends of the two floating members adjacent the main frame of the pallet truck, which crosspiece is fixedly secured to the ends of the floating members in order to provide stability and increased inertia to the entire floating mechanism. The ball bearings associated with the load cells are mounted adjacent a respective inner side-edge surface of the tine member, so that a wooden pallet with load may be more accurately weighed. Stop pins are also provided for preventing the accidental removal of the floating members and crosspiece.

Claims

1. In a pallet jack comprising a main frame and a fork member attached to said main frame, said fork member having a pair of spaced-apart tines for entry into a pallet for the subsequent lifting and transporting thereof to a remote site, said main frame comprising means for raising and lowering said fork member for lifting the pallet and the load thereon, wherein the improvement comprises:

means mounted on said fork member for weighing the load on the pallet during lifting and carrying by said fork member;

said means for weighing comprising a first floating member having a U-shaped cross section, and a second floating member also having a U-shaped cross section, each of said first and second floating members being mounted over a respective one of said tines of said fork member, each of said first and second floating members extending substantially along the entire length of the respective tine over which it is positioned;

each of said first and second floating members having a base portion and a pair of leg portions extending from the edge surfaces of said base portion to form said U-shaped cross section, said base portion extending parallel to the upper surface of the respective tine over which it is positioned, and each of said pair of leg portions extending downwardly in parallel relationship and spaced from a respective one of the side surfaces of the respective tine with which it is associated;

a plurality of load cell means for mounting in said fork member, each said tine of said fork member mounting at least one of said load cell means which weight a load positioned on said first and second floating members by the contact of the undersurfaces of said base portions of said first and second floating members with said plurality of load cells means;

each of said tines of said fork member comprising at least one cavity for mounting therein a respective one of said plurality of load cell means, such that each said undersurface is in contact with the upper portion of at least one load cell means associated with the respective tine of said fork member; and

said means for weighing further comprising a crosspiece having a first end fixedly connected to the end of said first floating member directly adjacent to said main frame, and a second end fixedly connected to the end of said second floating member directly adjacent to said main frame but spaced relative to said end of said first floating member.

2. The improvement according to claim 1, wherein each of said tines is provided with a pair of said load cell means spaced apart along the length of a respective one of said tines, one load cell means of each of said pair of load cell means being mounted directly adjacent to said crosspiece.

3. The improvement according to claim 2, wherein each of said load cell means is positioned directly adjacent to the inner-edge surface of a respective said tine, which inner-edge surface faces the other of said pair of tines.

4. The improvement according to claim 3, wherein said crosspiece connecting said ends of said first and second floating members directly adjacent to said main frame comprises a relatively thick, upstanding portion rising vertically upward from the top surfaces of said first and second floating members, said crosspiece providing substantial reinforcement to said first and second floating members to prevent excessive stress and attendant strain in said first and second floating members during the placement of the load thereon.

5. The improvement according to claim 1, wherein

each of said load cell means comprises an upper ball bearing having a portion thereof extending above the plane of the upper surface of a respective one of said base portions, and a portion thereof extending below a respective said undersurface;

each of said first and second floating members also comprising at least one downwardly-extending bearing surface for coacting with at least a respective said ball bearing, each of said plurality of load cell means further comprising means for generating a single indicative of the weight of the load on said first and second floating members, which means for indicating a signal is generated in response to force acting on said first and second floating members.

6. The improvement according to claim 1, wherein each of said load cell means is positioned in a respective one of said tines directly adjacent to an edge surface of the respective tine, said edge surface facing the other of said pair of tines.

7. In a lifting mechanism having a fork member comprising a pair of parallel first and second tines, means for lifting said fork member for lifting and carrying a load from one site to another site, and weighing means operatively connected to and associated with said fork member, wherein the improvement comprises;

said weighing means comprising a first load cell mounted to said first tine, and a second load cell mounted to said second tine;

each of said first and second load cells comprising an upper ball bearing having a portion thereof extending below the top surface of its respective tine, and a portion thereof extending above;

a first floating member for positioning on said first load cell on said upper ball bearing thereof, and a second floating member for positioning on said second load cell on said upper ball bearing thereof;

each of said first and second load cells being mounted on its respective tine directly adjacent to the inner edge surface thereof, which inner edge surface faces the other of said first and second tines;

means for mounting each of said first and second load cells in a respective said tine; and

a buttressing member having a first end fixedly connected to an end of one of said floating members, and a second end fixedly connected to an end of the other of said floating members; and

means for each of said floating members and buttressing member for preventing the accidental removal thereof from said fork member.

8. The improvement according to claim 7, wherein said means for preventing comprises a plurality of pins, and each of said floating members and said buttressing member comprises a larger-diameter opening for the insertion of a respective said pin therein.

9. The improvement according to claim 7, wherein said weighing means further comprises a third load cell comprising an upper ball bearing mounted directly beneath the lower surface of said buttressing member approximately at the center thereof as taken in a direction from said first end of said buttressing member toward said second end thereof, said lower surface of said buttressing member being positioned on said upper ball bearing of said third load cell at the approximate said center thereof, said first, said second, and said third load cells forming a triangular arrangement.

10. A method of weighing a load on a pallet truck, which pallet truck comprises a main frame, a projecting fork member having a pair of tines upon which the load is placed for the lifting thereby and the transporting thereof, the method comprising:

mounting at least one weighing load cell to each of the tines of the fork member at a location of each respective tine adjacent the inner side-edge surface thereof, which inner side-edge surface faces the other of the respective tines;

floatingly mounting a pair of elongated load-absorbing members over the upper surfaces of the pair of tines of the fork member, said step of floatingly mounting also comprising providing ball bearings between a lower surface of each of the floating members and the upper surfaces of the load cells;

said step of floatingly mounting further comprising emplacing the ball bearings adjacent the inner-edge surfaces of the tine members, which inner-edge surfaces face each other;

connecting the ends of the floating members directly adjacent the main frame so as to fixedly tie the movements of the floating members together so as to add structural integrity to the floating mechanism; and

placing a load to be weighed on both of the floating members floatingly mounted on the tines of the fork member.

11. The method according to claim 10, further comprising the step of mounting an additional load cell between the connected ends of the floating members directly beneath a crosspiece interconnecting the ends of the floating members formed by said step of connecting so that the undersurface of the crosspiece rests upon the additional load cell;

said step of mounting the additional load cell comprising arranging all of the load cells in a triangular array.