Chair raising and lowering mechanism

Claim 1

CHAIR RAISING AND LOWERING MECHANISM, COMPRISING A MOVABLE RAM ADAPTED TO BE SECURED TO THE SEAT OF A CHAIR FOR RAISING AND LOWERING SAID SEAT, AND MEANS FOR LOCKING SAID RAM IN A POSITION THEREOF, SAID LOCKING MEANS COMPRISING CLAMPING MEANS MOVABLE FROM AN INOPERATIVE RAM NON-LOCKING POSITION TO AN OPERATIVE RAM LOCKING POSITION, AND MEANS FOR OPERATING SAID CLAMPING MEANS COMPRISING A GUIDE MEMBER HAVING A GUIDE SLOT THERIN, A PIN MOVABLE IN SAID GUIDE SLOT FROM ONE POSITION CORRESPONDING TO SAID INOPERATIVE POSITION OF SAID CLAMPING MEANS TO ANOTHER POSITION CORRESPONDING TO SAID LOCKING POSITION OF SAID CLAMPING MEANS, MEANS SECURED TO SAID PIN AND HAVING A PART SPACED THEREFROM TO PROVIDE A PIVOT FOR MOVING SAID PIN FROM SAID ONE POSITION TO SAID OTHER POSITION, A MEMBER CONNECTED TO SAID PIN FOR ROTATING THE LATTER, SAID STOP MEANS IN THE PATH OF MOVEMENT OF SAID SPACED PART, FOR STOPPING THE MOVEMENT THEREOF DURING AN INITIAL MOVEMENT OF SAID PIN OPERATING MEMBER IN ONE DIRECTION SO THAT CONTINUED MOVEMENT OF SAID PIN OPERATING MEMBER IN SAID DIRECTION CAUSES SAID PIN TO PIVOT ABOUT SAID SPACED PART AND MOVE FROM SAID ONE POSITION THEREOF TO SAID OTHER POSITION THEREOF FOR OPERATING SAID CLAMPING MEANS, PUMPING MEANS INCLUDING A PLUNGER FOR RAISING AND LOWERING THE RAM, INCLUDING MEANS CONTROLLED BY OPERATION OF SAID SPACED PART FOR CONTROLLING SAID PLUNGER.