US761744A - Switch-contact. - Google Patents

Description

No. 761,744. PATBNTED JUNE '7; 1904.

G. WRIGHT.

SWITCH CONTACT.

APPLICATION FILED 00114, 1903.

N0 MODEL.

INVENTOR- Gilbeflz Wright? A. 4. W

ATTORNEY.

m: NORRIS PETERS cu. moruuma. WASHINGYON, one.

UNITED STATES Patented June '7, 1904.

PATENT OFFICE.

GILBERT WRIGHT, OF 'PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO STANLEY ELECTRIC MANUFACTURING COMPANY, OF PITTSFIELD, MASSACHUSETTS, A CORPORATIONOF NElV JERSEY.

SWITCH-CONTACT.

SPECIFICATION formingpart of Letters Patent No. 761,744, dated June '7, 1904. Application filed October 14, 1903. Serial No. 176,939 (No model.)

To (tZZ whom it may concern; Be it known that I, GILBERT YVRIGH T, acitizen of the United States, and a resident of Pittslield, hlassachusctts, have invented certain new and useful Improvements in Switch- Contacts, of which the following is a specification.

My invention relates to switches for electric circuits, and particularly to those switches which must open a circuit carrying a heavy current at high potential. that must be met by such switches arc very severe. Where the current capacity is large, the bearing-surface between the stationary and movable contact must be large. In order to secure this in switches as ordinarily constructed, the alinement of the parts must be perfect, and any departure from perfect alinement reduces the bearing-surface of the contacts to a very small area, which results in heating and deterioration of the contacts, thus increasing the original evil. Furthermore, where a switch is carrying a large current at high potential opening of the circuit produces arcing even where the contacts are submerged in oil. This arcing results in burning the contacts, which in switches of ordinary construction prevents good electrical contact being made when the switch is again closed. This evil is also cumulative, since it results in further heating and burning of the switch.

The object of my invention is to provide a contact for such switches which shall always offer a large and uniform bearing-surface for the contacts and in which all arcing produced by opening the switch shall take place at such points that the contact-surface when the switch is closed shall be in no way aifected.

1n the accompanying drawings, Figure 1 represents a view in elevation of a switch-contact constructed in accordance with my invention. Fig. 2 shows a second view in elevation at right angles to the first.

In the drawings, A represents the movable switch-blade, which is mounted on and insulated from the rotatable shaft B. In the The requirements drawings blade A is shown in the closed position, engaging the main stationary contact C. Stationary contact C is loosely mounted upon the rods D D D and is pressed down upon blade A by the spiral springs (Z (Z (Z, surrounding rods DD D. The spiral springs (Z (Z (Z abut at one end upon nuts E E E, by means of which the SDKIDg-PYGSUPG may be adjusted. Nuts F F F serve to limit the downward travel of the stationary contact C. The rods D D l) are supported from plate G, which in turn is supported by the insulator H.

M is a flexible strip of conducting material 7 connecting contact C to terminal rod N.

It is evident that with the construction above described a slight imperfection in the adjustment of blade A will in no way aifect the amount of bearing-surface. Contact C is made self-alining by means of the springs (Z (Z (Z, so that contact over the whole bearingsurface between bladeA and contact C is at all times assured.

J is an auxiliary contact which consists of a flat strip of conducting material pivoted at 1 and pressed upward against the lower surface of blade A by means of the spiral spring 71;, surrounding rod K.

L is a nut against which the lower end of spring 7': abuts and by means of which its compression may be adjusted. Auxiliary contact J is free to move upward under the pressure of spring is when blade A is withdrawn. The position of auxiliary contact J upon the withdrawal of blade A is shown in dotted lines in Fig. 2.

It is evident that contact J not only serves to increase the bearing-surface of blade A when it is closed, but by its upward movement maintains contact with blade A after blade A is moved out of contact with main contact C. Furthermore, owing to the curved end of contact J the arcing takes place between the lower edge of blade A and a part of the stationary contact J which does not act as a bearing-surface when the switch is closed. By means of this construction all arcing is removed from main contact C, and the eli ects of the arcing that takes place in no way diminish the bearing-surface when the switch is closed.

It is evident that by means of the construction above described I guard not only against the evils due to faulty alinement of contacts, but also against all deterioration of the contact-surface due to arcing. The contact as above described would probably in practice be immersed in oil, and I have shown a form of contact and support adapted for an oil switch. In the drawings, however, I have not shown an oil-tank, since many arrangements of oil-tanks are well known to the art and, furthermore, since the use of my contact is in no way limited to oil-switches.

I am aware that pivoted spring-pressed switch-contacts are old in the art and have been used for one purpose or another in a number of switches and have been described and illustrated in a number of patents. I am not aware, however, that a completely selfalining switch-contact has ever been used.

By completely self-alining I mean selfalining in every direction in the plane of contact, it being evident that a pivoted contact can be self-alining in a single direction only that is, in a direction at right angles to the axis of its pivot.

\Vhen the term completely self-alining is used in the following claims, it will be understood that self-alinement in every direction in the plane of contact is intended.

I do not desire to limit myself to the particular construction and arrangement of parts here shown, since changes therein which do not depart from the spirit of my invention and which are within the scope of the appended claims will be obvious to those skilled in the art.

Having thus fully described my invention, I claim as new and desire to protect by Letters Patent 1. In an electric switch, a movable switch member, and a completely selfalining contact adapted to be engaged thereby.

2. In an electric switch, a movable switch member, and a completely self-alining contact spring-pressed in a direction at right angles to the direction of motion of said member and adapted to be engaged by said member.

3. In an electric switch, a movable switch member, a plurality of rods perpendicular to the bearing-surface of said member, a contact loosely mounted to slide on said rods, and spiral springs surrounding said rods and adapted to press said contact upon the bearing-surface of said member.

4:. In an electric switch, a movable switch member, and a completely self-alining contact spring-pressed against said member.

5. In an electric switch, a movable switch member, a completely self-alining main contact adapted to be engaged by said member, and an auxiliary contact adapted to receive the are from said member when said member is withdrawn.

6. In an electric switch, a movable switch member having flat bearing-surfaces parallel to the plane of its motion, a completely selfalining main contact adapted to engage one of said surfaces, and a pivoted spring-actuated auxiliary contact adapted to engage the other of said surfaces.

7 In an electric switch, a movable switch member, a completely self-alining main contact adapted to be engaged thereby, and a pivoted, spring-actuated, auxiliary contact adapted to receive the are from said member as said member is withdrawn.

Signed at Pittsfield, Massachusetts, this 3d day of October, 1903.

GILBERT IVRIG H'I.

Vitnesses:

L. A. HAWKINS, R. E. HAYNES.

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