This is a complete, ready to use (except for some cleaning first) medical dental office chair.  Hydraulic power tilts the back, tilts the whole chair, raise the leg rest and changes the height of the chair.

 

Ritter Medical Products Model 119.  A 115 VAC electric motor drives a hydraulic pump integral to the unit that provides the motion.

 

The positions are controlled by a foot switch bar with up and down for each of the 4 motions.

  

In the image above, we have laid the back down.

In the image below, we have tilted the whole chair.

  

In the image above, we have partially raised the leg rest.
In the image below, we have raised the whole chair.

 

There is a built in "bed pan".  Not shown are the integral foot stirrups.