US1016833A - Electric-switch-contact holder. - Google Patents

Description

D. LARSON.

ELEGTRIG SWITCH CONTACT HOLDER.

APPLICATION FILED MAY 7, 1908.

1,016,833, Patented Fb.6,1912.

anus/1 1 q/vi-l 14000.00

UNITED STATES PATENT OFFICE.

DAVID LARSON, OF YONKERS, NEW YORK, ASSIG-NOR '10. OTIS ELEVATOR COMPANY,

OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY. I

ELECTRIC-SWITCH-CONTACT HOLDER.

Specification of Letters Patent.

Patented Feb. 6, 1912.

To all whom it may concern:

Be it lmown that 1, DAVID LARSON, a subject of the King of Sweden, residing at Yonkers, in the county of Westchester and State of New York, have invented a new and useful Improvement in Electric-Switch- Contact Holders, of which the following is a specification. I

My invention relates to electric switches, and one of its objects is the provision of an improved yielding contact holder.

Another, object of the present invention is the provision of an improved fixed contact holder.

Other objects of the invention will appear hereinafter, the novel combinations of elements being set forth in the appended claims.

Referring to the accompanying drawings, Figure 1 is a part sectional side elevation of an electric switch embodying my invention; Fig. 2 is a front elevation on an en larged scale of a portion of Fig. 1; and Fig. 3 is a sectional view of the stems of the clamping jaws.

The invention is adapted to beapplied to various forms of switches, both manual and automatic, but as it involves features that specially adapt it for use with switches operated by alternating current magnets, I have shown the invention embodied in a switch of this kind. To a base or-support 1 of slate or other insulating material is secured a bracket 2, to which is pivoted at 3 the switch arm 4. The, outward movement of the arm 4 is limited by a stop 5 in the path of movement of an extension 6 of the switch arm. An el'ectromagnet comprising a laminated frame 7 and a winding 8 is secured to the base 1, and its armature 9 is secured to the switch arm 4. A coil spring 10 surrounds a rod 11 which is pivoted at one end to the arm 4 and extends loosely through an opening in the base plate 1.

This spring serves to open the switch when the magnet is deenergized.

The switch arm 4 carries a movable contact 12 in the form of a flat. plate or disk having a stem 13, preferably rectangular or irregular in cross section, extending through the switch arm; The movable contact is inwasher 17 bearing against the washer 16 and the end of the sleeve 14. .The outer end 18 of the stem 13 is circular in cross-section and threaded to receive the nuts 19, 20 and 21. A metallic washer 22 is placed between the washer 17 and the-nut 19, a terminal 23 of an electric conductor is clamped between the nuts 19 and 20, and a lock nut 21 is curely in position on. the contact stem so that they will move with the contact 12.

The sleeve 24 extends loosely through an opening 42 in the switch arm and is yieldingly held in its forward position by a coil spring 27 which bears against the flange 25 and the rear end of which lies in a recess 28 formed in the switch arm. As the switch arm moves forward toward its closed position, the contact 12 engages the stationary contact 30 before the switch arm has reached its forward limit of movement, and the continued movement of the switch arm compresses the spring 27 and holds the switch contacts together with a yielding pressure. The spring 27 serves to hold the flat surfaces of the contacts 12 and 30 squarely in engagement with each other when the armature is in attracted position, as there is sufficient clearance between the sleeve 24 and the switch arm 'at the opening 42 to permit a slight angular movement of the contact 12 in any direction which may be necessary to make the contact surfaces parallel. The insulation prevents the spring 27 from becoming heated to such a temperature that its resiliency is destroyed and the metal I sleeve 14 and metal washer 26 take up wear.

The stationary contact 30 consists of a carbon block held between clamping jaws 31 and 32. The jaw 31 is formed with a stem 33 extending through the base 1 and having a threaded portion 34 extending be- .yond the base and forming a binding post for a conductor which may be clamped between the nuts 35 and 36. The nut 35 also serves to clamp the jaw 31 rigidly to the base, a washer 37 being placed between the nut 35 and the base. The movable clamping jaw 32 is provided with a stem 38 extending into the base 1 with its end abutting against a shoulder 39 formed on the stem 33. As shown in Fig; 3, the stems of the clamping jaws are both substantially semi-circular in cross-section, with their fiat surfaces par= allel and spaced a short distance apart. The end of the stem 38 is provided with a V- shaped projection 40 which engages a notch 41 in the stem 33 and forms 'a knife bearing permitting a rocking movement of the jaw 32 to insure good electrical contact between the clamping jaws and the carbon block 30. A screw 42 which passes freely through the body portion of the jaw 31 and is threaded into the body portion of the jaw 32, serves to clamp the jaws tightly against the carbon contact. 7 I

The jaw 31 with its stem 33-and end 34 'is preferably a single casting so that the only machining required is the threading of the end 34, the hole for the bolt 42 being formed when the jaw is cast. This construction permits the use of material like aluminumbronze which is a good conductor of electricity, but is hard andhnyielding. The jaw 32 is made of brass or bronze, or any other suitable elastic or springy material, but not necessarily a good conductor of electricity. The jaw31 being made of good conducting material, is suflicient to carry the ,current with little' loss of energy or heating, while the elastic jaw 32 maintains 3 a good contact between the carbon 30 and jaw 31 through a wide range of temperaturesa Thecarbon when it becomes heated does not expand as much as the metal, and.

parts and materials used as might be made by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims. I wish therefore not to be limited to the precise construction disclosed.

What I claim as new and desire to secure by Letters Patent of the United States is 1. In a switch, the combination with asupport formed with an opening therein, of

a pair of clamping jaws each having a stem extending into said opening, and means for securing the jaws together.

2. In a switch, the combination with a support, of a clamping jaw having a stem extending through an opening in the support, a threaded extension on the stem, a clamping nut on said extension, a second clamping jaw having a stem extending into said opening, and means for clamping said jaws to a switch contact.

In testimony whereof, I have signed my name to thisspecification in the presence of two subscribing witnesses.

Witnesses:

CHAS. M. NIssEN, JAMES D. 'IvERs.

DAVID LARSON.

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