GB539694A - Improvements relating to clutch mechanism for intermittently-operated power-driven machines - Google Patents

Abstract

539,694. Operating clutches. BAXTERS (BOLTS. SCREWS & RIVETS), Ltd., and DENT, W. C. June 29, 1940, No. 11050. [Class 80 (ii)] In clutch mechanism wherein a bolt or movable member is withdrawn to permit of clutch engagement and is afterwards moved into the path of a rotating control part of the clutch to cause clutch disengagement after the completion of a working stroke, there is provided a secondary release bolt mechanically connected to the primary bolt so as to move therewith but in reverse direction, so that should the main bolt fail to return to clutch-releasing position, the secondary bolt will be in an operattive position for effecting release. As applied to a dog-clutch, one end of a bolt 2 sliding in a block 1 is adapted to co-operate with a cam 4 on the driven member 5 of the clutch in order to withdraw the member and release the clutch. The opposite end of the bolt has a lateral projection 6 slidable in a slot 7 and adapted to be engaged by a pawl 8 on a lever 9, actuated by the starting treadle, to withdraw the bolt from the cam. A second bolt 10 parallel to the bolt 2 acts as a safety bolt and is loaded by a spring 13 which tends to retract the bolt but it may be moved forward to engage a cam 15 on the clutch member 5. A lever 18 pivoted on a pin 17 carries adjustable pins 19, 20 adapted to engage the rear ends of the two bolts. When the starting pedal is operated, the main bolt 2 is withdrawn by the pawl 8 acting upon the extension 6 and this movement projects the bolt 10 forwardly, but before this bolt can engage the cam 15, the pawl 8 is tripped by a pin 21 to release the bolt 2. The spring 13 then retracts the bolt 10 and through the lever 18 returns the bolt 2 forwardly ready to engage the cam 4. Should the main bolt, however, fail to return, the bolt 10 will remain in its forward position to engage the cam 15 and effect release of the clutch. Thus the clutch will always be released after one revolution. The bolt 2 may be releasably held in its projected position by a spring-pressed ball or plunger 22 and recess 23. The member 5 and cams 4, 15 may be prevented from rotating when the clutch is disengaged by a spring- loaded plunger 24 having a bevelled nose 26 engaging a groove 27. In a modification, the bolts 2, 10 are arranged to co-act with a single cam. In a further modification, Fig. 6, the bolts 2, 10 are adapted to act upon an arm 35 of a rotatable key lying in a groove in the driven shaft 32 and adapted to be rotated to engage one of a number of key-ways in a driving member. In a still further modification, the main bolt is loaded by a spring and withdrawn by a cable.