Apparatus for effecting relative vertical displacement between a movable platform and vertically oriented supports therefor

Claim 1

APPARATUS FOR EFFECTING RELATIVE VERTICAL DISPLACEMENT OF A MOVABLE WORKING PLATFORM AND VERTICALLY ORIENTED SUPPORTS THEREFOR, SAID APPARATUS COMPRISING, IN COMBINATION, RACK MEANS EXTENDING ALONG SAID SUPPORTS; JACKING MEANS OPERATIVELY CONNECTED WITH SAID PLATFORM FOR OSCILLATION RELATIVE THERETO FOR SELECTIVE SWINGING INTO AND OUT OF OPERATIVE ENGAGEMENT WITH SAID RACK MEANS; SAID JACKING MEANS COMPRISING TWO HYDRAULIC ACTUATOR SETS OFFSET FROM EACH OTHER WITH RESPECT TO SAID RACK MEANS; EACH HYDRAULIC ACTUATOR OF A SET COMPRISING A CYLINDER CONNECTET AT ONE END TO SAID PLATFORM AND A DOUBLE ACTING PISTON CONNECTED TO A PISTON ROD EXTENDING FROM THE OTHER END OF SAID CYLINDER AND CONNECTED TO A CROSS MEMBER ENGAGEABLE WITH TEETH OF SAID RACK MEANS; MEANS OPERABLE, WHEN ONE HYDRAULIC ACTUATOR SET IS IN OPERATIVE ENGAGEMENT WITH SAID RACK MEANS AND PERFORMING A DISPLACING OPERATION, TO OSCILLATE THE OTHER HYDRAULIC ACTUATOR SET INTO OPERATIVE ENGAGEMENT WITH SAID RACK MEANS, IN ADVANCE OF COMPLETION OF THE DISPLACEMENT OPERATION OF SAID ONE HYDRAULIC ACTUATOR SET, TO EFFECT A DISPLACING OPERATION IN OVERLAPPING AND CONTINUING RELATION WITH THE DISPLACING OPERATION EFFECTED BY SAID ONE HYDRAULIC ACTUATOR SET; EACH HYDRAULIC ACTUATOR SET COMPRISING FOUR HYDRAULIC ACTUATORS ARRANGED IN TWO PAIRS, THE TWO PAIRS OF EACH SET OPERATING IN SYNCHRONISM WITH EACH OTHER AND BEING ARRANGED ON LATERALLY OPPOSED SIDES OF SAID SUPPORTS; A FIRST CROSS MEMBER ASSOCIATED WITH EACH PAIR OF ACTUATORS AND INTERCONNECTING THE OUTER ENDS OF THE PISTON RODS THEREOF; A SECOND CROSS MEMBER ASSOCIATED WITH EACH PAIR OF ACTUATORS AND EXTENDING TRANSVERSELY THEREOF TO INTERCONNECT THE LOWER ENDS OF THE CYLINDERS OF THE PAIR OF ACTUATORS; FRAME COMPONENTS SECURED TO SAID ACTUATORS THE UPPER END OF THE RESPECTIVE CYLINDERS OF SAID ACTUATORS HAVING OSCILLATING BEARING ENGAGEMENT WITH DOWNWARDLY FACING SURFACES OF SAID FRAME COMPOENENTS; AND MEANS OPERABLE BETWEEN SAID FRAME COMPONENTS AND SAID ACTUATORS AND RESILIENTLY BIASING THE UPPER ENDS OF SAID ACTUATORS INTO BEARING ENGAGEMENT WITH SAID DOWNWARDLY FACING SURFACES OF SAID FRAME COMPONENTS.