James R Harmon

US Patent:

42828988, Aug 11, 1981

Filed:

Nov 29, 1979

Appl. No.:

6/144148

Inventors:

James L. Harmon - Joliet IL
John A. Junck - Sandwich IL

Assignee:

Caterpillar Tractor Co. - Peoria IL

International Classification:

F15B 13042

US Classification:

13759613

Abstract:

PCT No. PCT/US79/01033 Sec. 371 Date Nov. 29, 1979 Sec. 102(e) Date Nov. 29, 1979 PCT Filed Nov. 29, 1979 Heretofore the capability of operating a system (10), which supplies fluid to a hydraulic circuit (12), selectively at either a high or a low flow rate with only a single pressurized fluid source (14) has not existed. Such a system (10) includes a control valve structure (16) for controlling delivery of fluid from the source (14) to drive the circuit (12) and a flow control (22) for metering a portion of the fluid to the circuit (12). The capability of operating such a system (10) selectively at either a high or a low flow rate is advantageous in some modes of operation of the circuit (12). Herein, hydraulic circuitry (86) serves for controlling the magnitude of the portion in response to application of a signal thereto and a device (78) is provided for selectively applying the signal to the circuitry (86) for selectively directly controlling the magnitude of the portion.