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Linear or circular rachet-type locking device with automatic unlocking and self-locking

  • US 5,226,342 A
  • Filed: 07/15/1991
  • Issued: 07/13/1993
  • Est. Priority Date: 02/07/1989
  • Status: Expired due to Fees
First Claim
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1. A locking device (100;

  • 500) comprising the following components;

    a moving component (30;

         70) for moving between first and second extreme stop positions (Ia, IIa), and including at least a first notch and a second notch (50a, 50b;

         150) formed in the moving component (30;

         70) symmetrically about an axis of symmetry thereof and in positions corresponding to its extreme stop positions (Ia, IIa), with the bottoms of said notches having sections of appropriate profile (31-32-33;

    71-150-72);

    a ratchet (10;

         60) pivoting between a first stable equilibrium position and a second stable equilibrium position (Ib, IIb), which positions correspond to locking the moving component (30;

         70) in its above-mentioned first and second stop positions (Ia, IIa) respectively, which pivoting ratchet (10;

         60) is symmetrical about a plane including its pivot axis (35;

         55) and including on opposite sides of said plane a first locking finger (15,

         65) and a second locking finger (25;

         75) each for engaging in stable manner under the action of a load (F) acting on the moving component (30;

         70) in a corresponding one of the notches (50a, 50b;

         150) formed in the moving component, in correspondence with said extreme stop positions (Ia, IIa), and until a load (F'"'"') is applied to the moving component (30;

         70) in the opposite direction; and

    a spring (20;

         200) mounted in a prestressed condition so that its resilient reaction (R1;

    R2) establishes a moment about the pivot axis (35;

         55) of the ratchet (10;

         60), which moment acts in such a direction as to maintain said ratchet in its first or second stable equilibrium position (Ib, IIb), thereby locking the moving component (30;

         70) in its first or second extreme stop position (Ia, IIa), respectively, the spring (20;

         200) being mounted in such a manner that for a given resilient reaction (R1;

    R2) thereof, the distance of said reaction relative to the pivot axis (35;

         55) of the ratchet (10;

         60) in either of the two locking positions (Ib, IIb) is such that the ratchet (10;

         60) is unlocked by the application of the smallest load that may be applied to the moving component (30;

         70) in the direction for moving towards the other extreme stop position (IIa, Ia), such a ratchet-unlocking load (10;

         60) causing the ratchet to pivot towards a "switchover" position in which the moment of its resilient reaction (R1;

    R2) relative to the pivot axis (35;

         55) of the ratchet (10;

         60) becomes zero such that final switching over thereof to the other locking position (IIb, Ib) for locking the moving component (30;

         70) in said other extreme stop position (Ia, Ib) takes place automatically solely under drive from the above-mentioned ratchet-unlocking load.

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