Richard S Graham

US Patent:

41840593, Jan 15, 1980

Filed:

Oct 31, 1977

Appl. No.:

5/846844

Inventors:

Richard Graham - Centralia MO
Eugene L. Kamp - Fulton MO
Armin M. Bruning - Centralia MO
Earl S. Gritton - Centralia MO
L. Ronald Azdell - Mexico MO

Assignee:

A. B. Chance Company - Centralia MO

International Classification:

H01H 904
H01H 2108

US Classification:

200302

Abstract:

A high dielectric strength seal between the encapsulant and the outwardly projecting actuating arm of an externally operable encapsulated vacuum switch includes a fluid-receiving sealed cavity surrounding the actuating arm between the latter and the encapsulant. An externally accessible valve permits charging of the cavity with a dielectric fluid subsequent to encapsulation of the switch to insure displacement of air from the interface between the encapsulant and actuating arm, thereby greatly reducing the likelihood of corona formation and dielectric breakdown of the seal. Additionally, the dielectric fluid may be pressurized through the valve to preclude infusion of conductive contaminants into the cavity. In preferred forms, an accumulator is in fluid communication with the cavity to permit thermal expansion and contraction of the dielectric fluid without undesired leakage or cavitation of the liquid.

US Patent:

40478211, Sep 13, 1977

Filed:

Oct 13, 1976

Appl. No.:

5/732056

Inventors:

Jack B. Hoke - Centralia MO
Richard Graham - Centralia MO
Richard H. Hoffman - Moberly MO

Assignee:

A. B. Chance Company - Centralia MO

International Classification:

F16B 710

US Classification:

403109

Abstract:

An elongated, lightweight, insulative, multi-section, break-resistant telescoping tool especially adapted for work around energized electrical lines is disclosed which overcomes breakage problems heretofore encountered in tools of this type by provision of closely fitting, reciprocable, telescoping sections having imperforate bases which preclude air flow centrally through the sections to thereby prevent the quick escape of air from adjacent, surrounding sections during nesting retraction of the tool which serves to cushion such retractive movement and prevent inadvertant breakage of the sections. Spring-loaded buttons are provided for releasably securing the sections in an extended position and are formed of high-impact, shear-resistant deformable synthetic resin material so that the buttons can safely absorb shocks resulting from an accidental dropping of the tool without breakage of the tool sections or the buttons themselves. The tool sections advantageously include an outer tube formed of flexibilized epoxy resin and an inner fiberglass reinforced sleeve received within the tube and bonded thereto by means of a polyurethane foam which absorbs a portion of the transverse loads imposed iupon the sections by the buttons during an accidental dropping of the tool.