Charles T Mcdermott

Author:

Charles J. McDermott

ISBN #:

0685119858

Author:

Charles McDermott

ISBN #:

0895792729

US Patent:

45759766, Mar 18, 1986

Filed:

Jun 24, 1983

Appl. No.:

6/507349

Inventors:

Charles McDermott - Lakewood CA
Magbool A. Zafar - Fontana CA

Assignee:

Machine Products Corporation - Kansas City KS

International Classification:

E04H 1234

US Classification:

52118

Abstract:

An extension and retraction system for a multiple section, telescoping boom apparatus of the type utilized for raising and lowering a work platform or basket. The innermost longitudinally movable section is carried by a longitudinally inextensible or base section, and is extensible and retractable relative to the base section by a dual cylinder assembly. Extension chains trained about sprockets carried by certain of the sections automatically extend the other extensible sections upon extension by the cylinder assembly of the innermost longitudinally movable section. Automatic and positive retraction of such sections is accomplished by retraction chains operating in response to retraction of the innermost section. The cylinders of the dual cylinder assembly are pivotally coupled at a pivot mount longitudinally slidable along a guideway carried by the base section to thereby accommodate deflections of the boom sections located between the opposite extremities of the dual cylinder assembly. A feature of the apparatus is use of slide pads disposed between the boom sections to transmit loads, the pads being configured to accomplish this with minimum wear.