Continuously Connected Systems


A continuously connected hydraulic workholding system is one in which clamping pressure is derived from a continuous connection to a hydraulic power source. Such a system can range from a rudimentary welding fixture with a dozen clamps that are activated and maintained in position by a small stand-alone hydraulic power unit, to a sophisticated system using utilizing controls and hydraulic power units commonly found on today’s machining centers.
A stationary fixture with continuous supply.  

A key benefit of this type of system is that constant clamping pressure is assured because of the continuous hydraulic supply—there is no loss of pressure. Frequent applications of these types of systems are those in which the workholding fixture remains in the machining center for long machining cycles. Another example is when fixtures are dedicated to a particular machining center and not often changed. These fixtures can be single-sided, stationary fixtures or multi-sided rotating fixtures.

A stationary fixture with continuous supply.  
A two-sided rotating fixture. A vertical fixture   Connections
Because hydraulic lines are continuously connected to the fixture, care must be taken to insure the lines do not interfere with the machining process. Typical connection methods can be as simple as one hydraulic hose connected directly to the fixture or multiple lines connecting through the top or bottom of the fixture to control multiple circuits on the fixture. If the fixture must be able to rotate, a rotary union is required.
A two-sided rotating fixture. A vertical fixture like this is often referred to as a tombstone.”