US 3926495 A
Description (OCR text may contain errors)
Unite States Patent Pissarev et a1.
[ Dec. 16, 1975 ELECTRICAL CONTACT BODY Inventors: Angel Nikolaev Pissarev, Sofia;
Maria Pancheva Miteva, Plovdiv; Ivan Velev Balabanov, Plovdiv; Lyubomir Dimov Peychev, Plovdiv, all of Bulgaria Assignee: DSO ELPROM, Sofia, Bulgaria Filed: Nov. 15, 1974 Appl. N0.: 524,084
Foreign Application Priority Data Nov. 22, 1973 Bulgaria 25040 US. Cl. 339/48; 339/278 C Int. Cl. H01R 3/00; HOlR 25/00 Field of Search 339/48, 49, 91 R, 278 C,
References Cited UNITED STATES PATENTS 12/1901 Reichel 339/48 X 6/1941 Chiffey 1. 339/278 C 2,877,439 3/1959 Avery 339/151 M 3,259.870 7/1966 Winkler 339/49 R 3,573,710 4/1971 WOffOrd 339/49 B X 3,853,382 12/1974 Lazar 339/278 C X FOREIGN PATENTS OR APPLICATIONS 839,817 4/1939 France 339/91 R 1,490,729 6/1969 Germany 339/278 C Primary Examiner.1oseph H. McGlynn Assistant Examiner-Craig R. Feinberg [5 7] ABSTRACT 3 Claims, 5 Drawing Figures US. Patfint Dec. 16, 1975 3,926,495
ELECTRICAL CONTACT BODY This invention relates to an electrical contact body for contact commutation apparatus, particularly for low voltages.
An electrical contact body is known, which is used in low-voltage apparatuses such as contactors, relays etc., which is in the form of a parallelepiped with a spherical or flat contact surface. It is a drawback of this body that in commutation the apparatus is worn out irregularly since most part of the contact material in molten and- /or powdered form is carried away by electrodynamic forces outside the limits of the contact body.
It is a general object of this invention to provide an electrical contact body of such shape that in commutation a larger quantity of powdered and molten contact material is retained on its surfaces, whereby to achieve a higher wear resistance with the same quantity of contact material as that used in known bodies, or to achieve an equal resistance to' wear of the Contact with a reduced quantity of contact material.
These objects are achieved by the use of an electrical contact body consisting of a triangular prism with an isosceles triangle with rounded-off edges. The uppermost part of the contact has a spherical surface, which is situated near the peak which is formed by the equal legs of the base of the triangular prism. The remaining walls of the triangular pyramid are formed 'by tangents to the spherical surface.
For a better understanding of the invention, reference should be made to the accompanying drawings in which there are illustrated and described preferred embodiments of the invention.
In the drawings: I
FIG. 1 is a side elevational view of a first embodiment of the contact body of the invention;
FIG. 2 is a view in plan of the contact body of FIG. 1;
FIG. 3 is a cross-sectional view of the contact body of FIG. 1 through its highest portion, the section being taken along with line 3-3 of FIG. 1;
FIG. 4 is an illustration of the position of two opposing similar contact bodies in the contact system, wherein the arrow (1 indicates the direction of motion of the electric arc; and
FIG. 5 is a view in plan of a second embodiment of the contact body of the invention, such body having a lower portion shaped as a dovetail.
The first embodiment of the contact body designated 7 triangle with rounded-off peaks (FIG. 2) and a part similar to a triangular pyramid situated on the prism 1, which has the same base and rounded-off peaks. The uppermost portion of the Contact body (FIG. 3) has a spherical surface 3, drawn to the peak formed by the equal legs of the isosceles triangle of the base of the triangular prism 1. The remaining walls of the part 2 which is similar to a triangular pyramid are tangents to the spherical surface 3.
In order to provide more extended engagements between the uppermost parts of two opposing contact bodies, one of the contact bodies (usually the fixed one) can be made with a flat area in its uppermost portion. In the system of FIG. 4 the contacts are in engagement only at their uppermost spherical surfaces 3, which are of smallest width. The widest and lowest or base part of the contact bodies are oriented in the direction of motion d (FIG. 4) of the electric arc. The electric are produced is moved from the uppermost spherical surface 3 to the portion of smaller height that is, the base which is the widest part of the contact body.
FIG. 5 illustrates a variant of the contact body. The contact body C of FIG. 5 differs from the contact body shown in FIG. 2 in that the body of FIG. 5 is hollowed in its widest and lowest part in the shape of a dovetail.
Although the invention is illustrated and described with reference to a plurality of preferred embodiments thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a plurality of preferred embodiments, but is capable of numerous modifications within the scope of the appended claims.
1. An electrical contact body for a contact commutation apparatus, said contact body having a base in the form of a triangular prism having an isosceles triangular section with rounded-off peaks, a triangular pyramid with rounded-off edges disposed on said base, the uppermost portion of the contact body having a spherical surface disposed near the peak formed by the equal legs of the triangular prism base, the remaining walls of the triangular pyramid being tangents to the spherical surface.
2. An electrical contact body according to claim 1, wherein the body in its widest and lowest part is in the shape of a dovetail.
3. A pair of opposed electrical contacts of which one is formed according to claim 1 and the other is made according to claim 1 with the exception that the uppermost portion thereof is fiat.