US 4,394,102 A · Servo amplification system

Abstract

A servo amplification system is created particularly for heavy construction equipment, but has a general utility that is much broader. The system utilizes a hydraulic analog system with a separate subsystem for each dimension of motion. The operator moves the operative element, such as the backhoe bucket, of the analog replica which ordinarily would be situated in the cab of the backhoe or other piece of equipment. A small hydraulic cylinder operative in response to movement at each articulated connection of the backhoe operates a pilot valve which controls a pilot piston mechanically linked to the drive valve of the drive cylinder of the corresponding articulation in the actual backhoe. A feedback system comprising a mechanical link from the actual drive piston to a feedback cylinder and piston delivers hydraulic fluid back to the inlets of the pilot valve in such a way as to cancel the pilot orders from the initial control cylinder. The resulting action is virtually perfect analog simulation by the actual backhoe of the movements of the replica backhoe.

Claims13

Dependent claims

A servo amplification system comprising:

(a) a control cylinder having a double-acting control piston defining a first and second control chamber on opposite sides of said piston;
(b) a pilot valve and a pilot cylinder having a doubleacting piston and being operated by said pilot valve, said valve having a first and second inlet port connected to said first and second control chamber, respectively, to drive said pilot selectably in a first or second direction;
(c) a drive cylinder having a drive piston activated by a directional valve operated by said pilot cylinder;
(d) a feedback cylinder with a double-acting feedback piston operatively connected to said drive piston to be moved thereby, said feedback cylinder defining first and second feedback chambers on opposite sides of said feedback piston, said first and second feedback chambers communicating with said second and first inlet ports respectively, such that movement of said control piston in a first direction operates, through said pilot valve and cylinder, said drive cylinder which moves a distance proportional to the distance moved by said control cylinder.

1 more element

Dependencies are inferred from the claim text.

Servo amplification system

Life of this patent

Servo amplification system

Life of this patent

Abstract

Claims13