Lifting device

Claim 1

A LIFTING DEVICE OF THE CHARACTER DESCRIBED COMPRISING, IN COMBINATION, A GENERALLY RECTANGULAR TABLE MEMBER, SAID TABLE MEMBER BEING ADAPTED TO BE MOUNTED ON ADJUSTABLE LEGS HAVING LOCKING ROLLERS THEREON WHEREBY IT MAY BE MAINTAINED LEVEL AND STATIONARY ON AN UNEVEN SURFACE, SLIDE-SUPPORTING SHAFT MEMBERS MOUNTED ON THE UPPER SURFACE OF SAID TABLE AND ADJACENT EACH CORNER PORTION THEREOF, SAID SLIDE-SUPPORTING SHAFT MEMBERS BEING DISPOSED IN PARALLELISM TO EACH OTHER AND POSITIONED IN A COMMON PLANE PARALLEL TO THE UPPER SURFACE OF SAID TABLE MEMBER, A SCREW SHAFT HAVING REVERSELY THREADED PORTIONS AT EACH END THEREOF DISPOSED INTERMEDIATE OF AND PARALLEL TO SAID SLIDE-SUPPORTING SHAFT MEMBERS AND EXTENDING SUBSTANTIALLY THE LENGTH OF SAID TABLE MEMBER, BEARING PILLOW BLOCK MEANS FOR ROTATABLY MOUNTING SAID SCREW SHAFT IN THE COMMON PLANE OF SAID SLIDESUPPORTING SHAFT MEMBERS, A PAIR OF NUT MEMBERS AXIALLY SPACED FROM EACH OTHER ON EACH END OF SAID SCREW SHAFT AND THREADEDLY ENGAGING THE REVERSELY THREADED PORTION AT EACH RESPECTIVE END OF SAID SCREW SHAFT, A LOAD-BEARING SLEEVE COMPRISING A SLIDE MEMBER COAXIALLY ENGAGING EACH SLIDE-SUPPORTING SHAFT MEMBER FOR SLIDING MOVEMENT THEREALONG AND POSITIONED ABREAST OF ONE OF EACH PAIR OF SAID NUT MEMBERS, A PANTOGRAPH TYPE VERTICALLY MOVABLE PLATFORM HAVING LEG MEMBERS AT ITS LOWER END PIVOTALLY SECURED TO SAID LOAD-BEARING SLIDE MEMBERS, LINKAGE MEANS CONNECTING EACH PAIR OF SPACED NUT MEMBERS AT EACH END OF SAID SCREW SHAFT WITH THE PAIR OF LOAD-BEARING SLIDE MEMBERS POSITIONED ABREAST OF EACH PAIR OF SAID SPACED NUT MEMBERS AND FORMING A TRUSS-LIKE CONNECTION THEREBETWEEN, DRIVE MEANS ON SAID SCREW SHAFT POSITIONED INTERMEDIATE THE PAIRS OF SAID SPACED NUT MEMBERS THREADEDLY MOUNTED THEREON, SAID BEARING PILLOW BLOCK MEANS FOR SAID SCREW SHAFT BEING LOCATED SOLELY INTERMEDIATE SAID DRIVE MEANS AND SAID REVERSELY THREADED PORTIONS ON SAID SCREW SHAFT, MOTOR MEANS MOUNTED BENEATH SAID TABLE AND HAVING MEANS ENGAGING SAID SCREW SHAFT DRIVE MEANS THROUGH AN OPENING IN SAID TABLE MEMBER, AND MEANS FOR CONTROLLING SAID MOTOR MEANS FOR ROTATING SAID SCREW SHAFT IN OPPOSITE DIRECTIONS FOR RAISING AND LOWERING THE PLATFORM.