US 4,783,106 A · Method and apparatus for automatically controlling pressure in fluid-actuated systems

Abstract

The invention provides a method and apparatus for controlling the level of clamping pressure applied by a clamp to a load. A pump, whose output is controlled by a normally open valve, establishes an initial level of clamping pressure. Through the use of a number of controllable fluid discharge systems, this pressure is automatically increased in increments depending upon the resistance of the load to the clamping pressure exerted. In a preferred embodiment, the controllable fluid discharge systems include discharge cylinders that contain predetermined volumes of fluid dischargeable by free-floating pistons residing therein. The outputs of the discharge cylinders are controlled by pressure-responsive valves to produce the desired relationship between clamp pressure and load rigidity.

Claims24

Dependent claims

An apparatus, for automatically controlling the pressure applied by a clamp to a load, said clamp being closably actuated by the introduction of a fluid into a clamp actuator cylinder operatively coupled to said clamp, said apparatus comprising:

initial pressure establishment means, connected to said actuator cylinder, for producing an initial predetermined pressure in said actuator cylinder;
and
first controllable fluid discharge means, connected to said actuator cylinder, for discharging a first predetermined volume of said fluid to said actuator cylinder when said initial predetermined pressure in said actuator cylinder is reached.

An apparatus for automatically controlling the pressure applied by a clamp to a load, said clamp being closably actuated by the introduction of a fluid into a clamp actuator cylinder operatively coupled to said clamp, said apparatus comprising:

pressure establishment means for transferring fluid to said actuator cylinder;
an initial conduit connecting said pressure establishment means to said actuator cylinder;
valve means for interrupting the flow of fluid in said initial conduit between said pressure establishment means and said actuator cylinder, said valve means interrupting the flow of fluid when an initial pressure in said actuator cylinder is reached;
first controllable fluid discharge means, connected to said actuator cylinder, for discharging a first predetermined volume of said fluid to said actuator cylinder when said initial predetermined pressure in said actuator cylinder is reached;
and
second controllable fluid discharge means, connected to said actuator cylinder, for discharging a second predetermined volume of said fluid to said actuator cylinder when the discharge of said first volume of fluid to said actuator cylinder increases the pressure in said actuator cylinder by a predetermined amount.

3 more elements

An apparatus for controlling the pressure developed by the introduction of a fluid into an actuator cylinder from a fluid source, said apparatus comprising:

first controllable fluid discharge means for discharging a first predetermined volume of said fluid to said actuator cylinder, said first fluid discharge means comprising a first discharge cylinder having a first free-floating piston disposed between a source-end of said first cylinder and an actuator end, said source being for introducing fluid into said source-end and forcing said first piston toward said actuator end of said first cylinder when said pressure in said actuator cylinder exceeds a first predetermined pressure, discharging said first volume of fluid to said actuator cylinder;
and
second controllable fluid discharge means, connected to said actuator cylinder, for discharging a second predetermined volume of said fluid to said actuator cylinder when the discharge of said first volume of fluid to said actuator cylinder increases the pressure in said actuator cylinder by a predetermined amount.

Dependencies are inferred from the claim text.

Method and apparatus for automatically controlling pressure in fluid-actuated systems

Life of this patent

Method and apparatus for automatically controlling pressure in fluid-actuated systems

Life of this patent

Abstract

Claims24