Actuator with wear compensating chamber

  • US 5,235,898 A
  • Filed: 12/09/1991
  • Issued: 08/17/1993
  • Est. Priority Date: 12/07/1990
  • Status: Expired due to Fees
First Claim
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1. A fluid-operated actuator for controlling the movement of a motor vehicle friction clutch having a diaphragm between an engaged position and a disengaged position, through a linkage coupling the actuator to the clutch diaphragm, said actuator comprising:

  • a main cylinder;

    a movable piston sub-assembly comprising;

    a main piston mounted for movement in the main cylinder and having a cylindrical bore, said main piston and said main cylinder defining a control chamber;

    a secondary piston movably mounted in said cylindrical bore to define therein a wear compensating chamber, said secondary piston adapted to be coupled to said linkage, wherein said secondary piston constitutes a coupling means for coupling said linkage to said main piston, said coupling means being in piston-and-cylinder relationship with said main piston;

    wherein said actuator further comprises;

    resilient booster means for resiliently applying a force to and connecting an outer sleeve with said piston sub-assembly, said outer sleeve fixed with respect to said main cylinder;

    a resilient return means for applying a lighter force than the resilient booster means and engaging said piston sub-assembly;

    loose coupled driving means for coupling said resilient booster means with said piston sub-assembly through said resilient return means, said loose coupled driving means being interposed between said resilient booster means and said resilient return means;

    a stop element carried by the main cylinder for limiting the travel of the main piston;

    a shut-off valve carried by said main piston for bringing said control chamber and said wear compensating chamber into communication with each other when said clutch is in said clutch engaged position;

    whereby said return means bias said piston sub-assembly towards the stop element so as to open the shut-off valve in the engaged position of the diaphragm.

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