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Procedure and apparatus for the handling of loads

  • US 5,292,219 A
  • Filed: 05/06/1992
  • Issued: 03/08/1994
  • Est. Priority Date: 02/23/1990
  • Status: Expired due to Term
First Claim
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1. Gripper for a fork-lift truck for handling paper rolls, the gripper comprising a lifting device with which at least one roll can be lifted by at least one lifting cylinder, operating by means of a working fluid, and jaws closed to grasp said at least one roll by at least one compression cylinder, operating by means of a working fluid, the gripper further comprising:

  • at least one measuring device for measuring continuously the slippage between said at least one roll and the jaws;

    at least one pressure sensing device for measuring the pressure of a working fluid flowing into said at least one compression cylinder producing a compressive force; and

    a control unit for controlling said at least one lifting cylinder to lift the jaws with said at least one roll, after the compressive force reaches a predetermined precompression value, and for increasing the compressive force in a continuum from the predetermined precompression value, to a value at which there is no slippage between said at least one roll and the jaws;

    wherein the device measuring the slippage is a pulse counting device and is so mounted on a jaw flap at the end of a jaw that it comes into contact with said at least one roll;

    wherein the compressive force is increased from the predetermined precompression value in proportion to the amount of slippage measured by the measuring device;

    wherein the gripper is provided with at least one valve which admits a small flow of working fluid into the lifting cylinder to facilitate a preliminary lifting operation; and

    wherein the gripper is provided with a pressure limiting valve to limit the pressure of the working fluid admitted into said at least one compression cylinder once slippage between said at least one roll and the jaws ceases.

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