Tensioners for chains, belts and the like

Claim 1

A TENSIONER FOR FLEXIBLE POWER TRANSMISSION MEMBERS, WHICH TENSIONER COMPRISES TWO CO-AXIAL MEMBERS RELATIVELY MOVABLE AXIALLY AND ROTATABLY ABOUT THEIR AXIS, A HELICAL SLOT ON ONE MEMBER, THE SAID HELICAL SLOT HAVING OPPOSED SIDE WALLS, ONE SIDE WALL COMPRISING A SMOOTH WALL AND THE OTHER SIDE WALL BEING PROVIDED WITH AN INCLINED FACE, A PROJECTING PART ON THE OTHER MEMBER, THE PROJECTING PART EXTENDING INTO THE HELICAL SLOT, BIASSING MEANS ACTING BETWEEN THE MEMBERS TO BIAS TOGETHER THE PROJECTING PART AND THE SAID SMOOTH WALL, WHEREBY THE MEMBERS TEND TO UNDERGO RELATIVE ROTATIONAL AND AXIAL MOVEMENT AND THE SAID PROJECTING PART TENDS TO MOVE ALONG THE SMOOTH WALL FROM ONE END THEREOF TOWARDS THE OTHER, A RECESS IN THE SAID ONE END OF THE SMOOTH WALL, WHEREBY WHEN THE SAID PROJECTING PART ENGAGES IN THE RECESS THE AFORESAID MOVEMENT UNDER THE ACTION OF THE BIASSING MEANS IS PREVENTED, THE SAID PROJECTING PART BEING DISENGAGEABLE FROM THE RECESS BY RELATIVE AXIAL MOVEMENT OF THE MEMBERS AGAINST THE ACTION OF THE BIASSING MEANS, THE SAID INCLINED FACE BEING POSITIONED OPPOSITE THE RECESS SO THAT WHEN THE MEMBERS ARE MOVED RELATIVELY AXIALLY TO DISENGAGE THE SAID PROJECTING PART FROM THE RECESS AND TO MOVE THE SAID PROJECTING PART IN SLIDING ABUTMENT OVER THE INCLINED FACE, THE MOVEMENT OF THE SAID PROJECTING PART IN SLIDING ABUTMENT OVER THE INCLINED FACE CAUSES RELATIVE ROTATION OF THE MEMBERS WHEREBY RE-ENGAGEMENT OF THE SAID PROJECTING PART WITH THE RECESS WHEN THE MEMBERS ARE RELEASED IS AVOIDED AND THE MEMBERS ARE FREED FOR RELATIVE MOVEMENT UNDER THE ACTION OF THE BIASSING MEANS AS AFORESAID.