Hydraulically operated portable scaffold

Claim 1

APPARATUS FOR ELEVATING OR LOWERING A SUBSTANTIALLY HORIZONTAL PLATFORM COMPRISING A BASE, A PLURALITY OF VERTICALLY-EXPANDABLE HYDRAULIC CYLINDER DEVICES INTERPOSED AT SPACED POINTS BETWEEN THE BASE AND THE PLATFORM, EACH OF SAID HYDRAULIC CYLINDER DEVICES HAVING THE SAME VOLUMETRIC CAPACITY, HYDRAULIC PUMPING MEANS FOR SUPPLYING FLUID UNDER PRESSURE TO SAID HYDRAULIC CYLINDER DEVICES, A PLURALITY OF HYDRAULIC PUMP-MOTORS EACH HAVING AN INLET PORT ADAPTED TO BE CONNECTED TO SAID HYDRAULIC PUMPING MEANS, AN OUTLET PORT FOR EACH PUMP-MOTOR CONNECTED TO AN ASSOCIATED ONE OF SAID HYDRAULIC CYLINDER DEVICES, GEAR MEANS OPERATIVELY CONNECTED TO EACH PUMP-MOTOR AND ADAPTED TO BE ROTATED BY A FLOW OF FLUID UNDER PRESSURE BETWEEN SAID INLET AND OUTLET PORTS, A SEPARATE HYDRAULIC PUMP-MOTOR HAVING AN INLET PORT ADAPTED TO BE CONNECTED TO SAID HYDRAULIC PUMPING MEANS, AN OUTLET PORT FOR THE SEPARATE PUMP-MOTOR, GEAR MEANS OPERATIVELY CONNECTED TO SAID SEPARATE PUMP-MOTOR AND ADAPTED TO BE ROTATED BY A FLOW OF FLUID UNDER PRESSURE BETWEEN THE INLET AND OUTLET PORTS, EACH OF SAID PLURALITY OF HYDRAULIC PUMP-MOTORS AND SAID SEPARATE HYDRAULIC PUMPMOTOR BEING CIRCUMFERENTIALLY SPACED ABOUT A COMMON AXIS, GEAR MEANS ROTATABLE ABOUT SAID COMMON AXIS AND ARRANGED TO OPERATIVELY ENGAGE THE GEAR MEANS OF EACH OF SAID PUMP-MOTORS WHEREBY ALL OF THE PUMP-MOTORS WILL DELIVER FLUID UNDER PRESSURE AT THE SAME RATE, AND THE VALVE MEANS FOR SELECTIVELY CONNECTING SAID HYDRAULIC PUMPING MEANS TO THE INLET PORTS OF SAID PLURALITY OF PUMP-MOTORS TO CAUSE EACH PUMP-MOTOR TO DELIVER FLUID UNDER PRESSURE AT THE SAME RATE TO ITS ASSOCIATED HYDRAULIC CYLINDER TO EXPAND ALL OF THE CYLINDERS IN SYNCHRONISM, SAID VALVE MEANS BEING ADAPTED TO SELECTIVELY CONNECT SAID HYDRAULIC PUMPING MEANS TO THE INLET PORT OF SAID SEPARATE HYDRAULIC PUMP-MOTOR WHEREBY THE SEPARATE HYDRAULIC PUMP-MOTOR WILL DRIVE THE PLURALITY OF HYDRAULIC MOTORS TO EXPEL FLUID FROM ALL OF SAID CYLINDERS AT THE SAME RATE TO RETRACT THE HYDRAULIC CYLINDERS IN SYNCHRONISM AND LOWER SAID PLATFORM.