Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS2613243 A
Publication typeGrant
Publication dateOct 7, 1952
Filing dateNov 5, 1948
Priority dateNov 5, 1948
Publication numberUS 2613243 A, US 2613243A, US-A-2613243, US2613243 A, US2613243A
InventorsFrear Oscar W S
Original AssigneeFrear Oscar W S
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Safety ground clamp
US 2613243 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

Oct. 7, 1952 o. w. s. FREAR 2,613,243,

SAFETY GROUND CLAMP Filed Nov. 5. 1948 Oscar W. 5. Frear Patented Oct. 7, 1952 UNITED STATES PATENT OFFICE Oscar W. S. Frear, Williamsport, Pa. Application November 5, 1948, Serial No. 58,473 I The present invention relates to certain new and useful improvements in a structurally and functionally novel safety ground clamp and the obvious objectof the invention is to provide for the grounding of highvoltage electrical equipment which has been de-energized and taken out of service for repair; equipment such as, for example, transformers, oil circuit breakers, high tension electrical lines, capacitators, generators, condensers and the like.

The outstanding purpose of the invention is for temporarily grounding the stated equipment whereby to safeguard and protect the lives of workmen working on ole-energized or dead equipment and is not to be confused with so-called live line connectors and clamps.

j Another object of the invention is to provide a safety; ground clamp characterized by a pair of opposedpivotally connected gripping jaws for an overhead line or other current conductor, said jaws being provided with selectively usable and reliable grippinggsurfaces to accommodate the variousgages of lines encountered ranging from small to large.

In reducing to practice a preferred embodiment of the invention I provide a pair of complemental jaw units hingedly connected together, one unit carrying a feed and adjusting screw and the other unit having a socket for accommodating the headed end of the screw with the walls of the socket having predetermined inclined planes in order to provide not only a swivel connection but a connection with requisite end thrust properties for swinging and effectively clamping the movable jaw against the relatively stationary jaw.

A further object of the invention is to provide 'a simple and feasible safety ground clamp which functions admirably well in taking a given line out of service for maintenance, such as changing of insulators or repairing the line in a manner to minimize injury to workmen, said clamp being highly simple, efficient in action and economical to all concerned.

Other objects and advantages will become more readily apparent from the following description and the accompanying illustrative drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the views:

Figure l is a perspective view of a safety ground clamp constructed in accordance with the principles of the present invention showing the jaws partly open;

Figure 2 is a central longitudinal sectional view on a slightly enlarged scale, with parts in eleva- 1 Claim. (Cl. 173-273) tion and showing the opening and closing movements of the movable jaw in full and dotted lines,


Figure 3 is a cross-section on the line 3-3 of Figure 2, looking in the direction of the arrows; Figure 4 is a horizontal fragmentary section on the horizontal line 4-4 of Figure 2, looking in the direction of the arrows; I

Figure 5 is a bottom plan view of the movable jaw.

Referring now to the drawings by distinguishing reference numerals it will be observed that there are three principal parts, namely, the primary jaw unit I, the complemental secondary jaw unit 8 and the adjusting and clamping screw 9. a

The unit I comprises an elongated jaw ID with a milled gripping surface II. Jaw I6 is at one end of the body of said unit and at the opposite end I provide a lug I2 with an aperture I3 to accommodate the ground wire (not shown). At th junctnral point between thelug and jaw I provide a lateral extension which constitutes a mount l4 and this has a horizontal screwthreaded hole I5 to accommodate the threads It of the adjusting and retaining bolt ll, which latter, at the left hand end, may be provided with a tool lug I3 to facilitate turning the same. The

opposite end of the screw is formed with a substantially spherical head or ball Ila. Unit 1 also has an ear I9 which serves to accommodate a pair of spaced parallel complemental ears 2!] formed as an integral part of the jaw unit 8. The several ears are hinged or pivoted together as at 2| and the unit 8 is located opposite to the jaw Ill and includes a relatively movable companion jaw 22. The face of the jaw 22 has several distinct transverse grooves or notches, the larger one denoted at 23, the smaller one at 24 and the intermediate one at 25. The last two grooves are diagonal to the longitudinal dimension of the jaw unit and the first notch 23 is at approximate right angle. Said jaw unit is recessed to provide what maybe identified as a socket 26 for the head Ila and the walls of the socket are properly shaped to provide cams or inclined planes as brought out in Figure 2. Consequently, by threading, the feed screw I'I back and forth through the mount I4, the coaction of the ball jointing head Ila with the socket and inclined surfaces 26 provides not only the desired hinging movement of the relatively movable jaw but maintains the desired fixed clamping result. Incidentally, the slot or notch 23 will accommodate a heavy conductor and may be used for 2,613,243 v Y a grounding 350,000 CM to 750,000 CM wire. The intermediate notch 25 is for grounding /0 t 300,000 CM wire; While the remaining smaller slot 24 is for grounding No. 6 to 1/0 wire.

As stated, the clamp is not to be confused with similarly constructed and appearing live lines connectors and is primarily adapted for temporarily grounding different types of electrical apparatus while. providing protection for men working on de-energized or dead equipment, as will be clear to persons skilled in the art to which the invention relates.

It is thought that persons skilled in the art to which the invention relates will be able to obtain a clear understanding of the invention after considering the description in connection with the drawings. Therefore, a more. lengthy description is regarded as unnecessary.

Minor changes in the shape, size and arrangement of details coming within the field of invention claimed may be resorted to in actual practice, if desired.

Having described the invention, what. is claimed as new is:

A. high tension line, safety ground clamp for the protection of workmen working on deenergized or dead electrical equipment which has been temporarily taken out of: service for repair comprising a relatively stationary jaw unit embodying a one-piece elongated body of current conductingmaterial fashioned at one end into a relatively long substantially flat faced jaw, and fashioned at its other end into an apertured line attaching lug, said lug being in a substantial plane with said body and jaw, said jaw being provided intermediate its ends with a lateral ear,

and said body being provided adjacent said ear and inwardly of the apertured lug with a permanentlateral extension, the latter substantially paralleling and bein in alignment with said ear and having a, screw-threaded hole in approximate parallelism with said jaw and constituting a mount for a feed screw, a relatively movable jaw unit also of current conducting material and including a body portion having a jaw opposed to said first-named jaw and swingable toward and from the latter, said relatively movable jaw unit being of a length approximately equal to that of said first-named jaw and having an end portion terminating in close spaced parallelism with said mount and provided with a cavity forming a socket, said socket hooding over said ear and being open on the side facing and confronting said extension and open at the bottom and having spaced parallel ears straddling, andhin edly connected with said ear, the walls of said socket being at approximate right angles to said first jaw and characterized by inclined planes of predetermined inclinations, and a metal feed screw overlying said lug in spaced parallelism and adjustably mounted in the screw-threaded hole and having tool accommodating means at one end extending beyond said lug and a ball jointing head at the opposite end, said head fitting into and being swivelly and positively coupled with said socket, said head; having. endv thrust cam coaction with the inclined. wallsv in said socket. said ball and socket connection being in close, proximity to the hinge commotion between said ears.



The following references are; of. record in the file of this patent:


Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1633098 *Jan 26, 1925Jun 21, 1927Henry HeeseLightning-arrester system
US1669337 *Sep 30, 1925May 8, 1928Arthur Iler GeorgeLive-line clamp
US1720003 *Oct 18, 1927Jul 9, 1929Providence Machine WorksBattery-post connecter
US1739090 *May 11, 1927Dec 10, 1929Westinghouse Electric & Mfg CoCombined trolley-feeder clamp
US1860262 *Aug 5, 1931May 24, 1932Niemann Jesse LElectrode electric welding device
US2114940 *Oct 14, 1936Apr 19, 1938Railway & Industrial Eng CoElectrical connecter
US2144140 *Jan 24, 1938Jan 17, 1939Standard Mfg CoClamping device
US2394204 *May 20, 1944Feb 5, 1946Randall Earl AElectrode holder
US2461687 *Jul 19, 1946Feb 15, 1949Grand Specialties CompanyWelder's clamp
DE635238C *Jun 10, 1934Sep 12, 1936Schleicher OskarDoppelhubschaftmaschine
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2726693 *Jan 9, 1953Dec 13, 1955Saxton John NFixture clamp with pivotally mounted actuating screw
US2923994 *Oct 28, 1958Feb 9, 1960the United States of America as represented by the Secretary of the Air Force Application October 28johnson
US3080645 *Dec 14, 1959Mar 12, 1963Moreland Ethelbert HCompressor for valve springs of engine with overhead valves
US3128090 *May 28, 1962Apr 7, 1964Northrop CorpFixture for chucking components
US3274657 *Mar 5, 1964Sep 27, 1966Renfroe & Sons J CSafety clamp
US3892455 *Mar 26, 1974Jul 1, 1975Thomas & Betts CorpGround clamp connector
US4190224 *Jun 14, 1978Feb 26, 1980Leblanc Edgar JIntravenous pole holder
US4203583 *May 19, 1978May 20, 1980Universal Instruments CorporationRadial lead component insertion machine
US4658687 *Oct 8, 1985Apr 21, 1987Shopsmith, Inc.Saw fence
US4986771 *Oct 13, 1989Jan 22, 1991The Richards-Braswell Research CorporationClamping device
US6964085 *Apr 11, 2003Nov 15, 2005Boda James CMounting clip and related modular storage system
US7792602Aug 22, 2007Sep 7, 2010Precision Automation, Inc.Material processing system and a material processing method including a saw station and an interface with touch screen
US7849781Jun 8, 2005Dec 14, 2010Defenshield, Inc.Bullet resistant barrier
US7891283May 4, 2007Feb 22, 2011Defenshield, Inc.Collapsible ballistic resistant defense unit
US8001880May 5, 2008Aug 23, 2011Defenshield, Inc.Barrier
US8079613 *May 11, 2006Dec 20, 2011Marty WilliamsHitch pin securing system for receiver mounted assemblies
US8371207Jul 15, 2011Feb 12, 2013Defenshield, Inc.Barrier
US8590439Jan 8, 2013Nov 26, 2013Defenshield, Inc.Barrier
US8726782Sep 20, 2010May 20, 2014Defenshield, Inc.Bullet resistant barrier
US20040026934 *Apr 11, 2003Feb 12, 2004Boda James C.Mounting clip and related modular storage system
US20070262563 *May 11, 2006Nov 15, 2007Marty WilliamsHitch pin securing system for receiver mounted assemblies
US20080271652 *May 5, 2008Nov 6, 2008Defenshield, Inc.Barrier
US20080294130 *Nov 7, 2005Nov 27, 2008Christian SimmetDevice and Technique for Semen Collection from Boars
EP1168954A1 *Mar 24, 2000Jan 9, 2002Kevin F. KagerHairstyling accessory holder
EP1168954A4 *Mar 24, 2000Apr 7, 2004Kevin F KagerHairstyling accessory holder
EP1660276A1 *Aug 6, 2004May 31, 2006Colin Patrick HealyA clamp
EP1660276A4 *Aug 6, 2004Dec 31, 2008Colin Patrick HealyA clamp
EP2144333A1 *Jul 8, 2008Jan 13, 2010Intercable SrlBypass and earthing device with grip clamp and cable connecting element
WO2015042293A3 *Sep 18, 2014Jun 18, 2015Patrick VincentEvacu zip and carry strap with clamp
U.S. Classification439/806, 269/245, 24/515, 269/238, 269/286, 24/517, 24/456
International ClassificationH01R4/64, H01R11/11, H01R11/26
Cooperative ClassificationH01R4/64, H01R11/26
European ClassificationH01R4/64, H01R11/26