Drive system for telescopic legs for tables
A hydraulic drive system readily adapted for either manual actuation or motor-driven actuation due to the unique design of the hydraulic drive and its coupling to either a hand crank or to a motorized drive to provide hydraulic pressure to lift cylinders that can be attached to table legs for vertical adjustment. The hydraulic drive includes a screw jack having an end extending from one end of a housing and splined or otherwise keyed. A manual crank arm or motorized drive assembly includes a coupling which mates with the end of the screw jack to provide a drive force for the hydraulic cylinder drive. The motorized drive assembly includes a pair of toothed hubs and an intermediate flexible sleeve allowing alignment of the motorized drive to the drive assembly as well as providing sound dampening, a cushioned coupling, and facilitates overcurrent detection.
1. A drive system for controlling hydraulic cylinders used in a lift system comprising:
a housing including a screw jack having an end extending from said housing;
a thrust nut coupled to said screw jack, wherein said housing is generally rectangular and said thrust nut is shaped to slide along the inside surface of said housing, and wherein said thrust nut includes a body having a plurality of axially spaced ribs which engage an inner surface of said housing to minimise the frictional engagement of said thrust nut with said housing;
at least one hydraulic cylinder including a piston rod coupled to said thrust nut such that rotation of said screw jack provides pressure to said hydraulic cylinder, wherein said thrust nut includes an aperture extending therethrough such that an end of said piston rod can be mounted to said thrust nut and be removed by pushing said rod from a side of said thrust nut opposite the cylinder with which said piston rod is associated; and
wherein said end of said screw jack is configured to receive one of a manual crank arm and a drive motor assembly for the rotation of said screw jack.
2. The drive system as defined in claim 1 wherein said thrust nut is made of a polymeric material.
3. The drive system as defined in claim 2 wherein said polymeric material is acetal.
4. A drive system for controlling hydraulic cylinders used in table lift system comprising:
a housing including a screw jack having an end extending from said housing;
a thrust nut coupled to said screw jack, wherein said housing is generally rectangular and said thrust nut is shaped to slide along the inside surface of said housing and wherein said thrust nut includes a body having a plurality of axially spaced ribs which engage an inner surface of said housing to minimize the frictional engagement of said thrust nut with said housing;
at least one hydraulic cylinder including a piston rod coupled to said thrust nut such that rotation of said screw jack provides pressure to said hydraulic cylinder and wherein said trust out includes an aperture extending therethrough such that an end of said piston rod can be mounted to said thrust nut and be removed by pushing said rod from a side of said thrust nut opposite the cylinder associated with which said piston rod is associated;
wherein said end of said screw jack is configured to receive a drive motor assembly; and
a drive motor assembly coupled to said housing the rotation of said screw jack.
5. The drive system as defined in claim 4 wherein said thrust nut is made of a polymeric material.
6. The drive system as defined in claim 5 wherein said polymeric material is acetal.