John T Sholes

US Patent:

43685218, Jan 11, 1983

Filed:

Sep 30, 1980

Appl. No.:

6/192646

Inventors:

John T. Sholes - Marion OH

Assignee:

Dresser Industries, Inc. - Dallas TX

International Classification:

G06F 1520
E02F 346

US Classification:

364506

Abstract:

Method and Apparatus are described for effecting tightline protection in a dragline excavating machine or the like. The described technique uses optical shaft encoders to provide binary coded decimal inputs related to the amount of hoist and drag rope paid out to digital logic. The control algorithm for the digital logic considers both static and dynamic conditions to optimize the permissible operating range of the dragline. In the digital logic device, signals corresponding with the amount of rope paid out from the dragline hoist and drag drums are added and compared with predetermined constants to sense a tightline condition. If either a static or dynamic tightline condition is sensed, indications are provided and cause motion brakes to be set in the machine. The same data can be used to electronically indicate limits of bucket travel.