How does the piston work on a Dover Relay Hydro : LUSENET : Elevator Problem Discussion : One Thread

I am not familar with this type of elevator. i understand that there is not a in ground cylinder. How does the car move? And how is the hydralic line connected to the car /

-- Mike Watson (, February 28, 2005


Sounds like you are referring to a "holeless hydraulic" produced in several versions by Dover, styled as the IVO, Cimmaron and other names.

These work like any other hydraulic elevator; it is just that the jack unit is above ground and is basically at the front of the car rather than below it. With the IVO, the cylinder is the moving part and the plunger is stationary. With the basic Cimmaron design, the plunger attaches to the car frame at a level higher than the car ceiling, the plunger moving to raise or lowewr the car, just as in a conventional hydro.

To the best of my knowledge, all these had solid state logic controls, although the control panels do have some relays on them.

-- John Brannon (, February 28, 2005.

Sounds like it might be a telescopic jack. Think of a car radio antenna, that collapses unpon itself. Oil fed in from the bottom of the jack expands one section, and when that has reached its full extension, the next larger section fills with oil and extends. The GMV jacks are a little different, in that they extend at the same time, and are synchronised by a system of chains. One end of the chain is fixed to the wall, and goes down around a cog on the jack section head, and is connected to the bottom of the next upper jack section head.

The uppermost section of the jack is bolted directly to the side of the car, attatched at the top of the car frame.

Hope this helps.

-- liftfixer (, March 01, 2005.

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