US2286163A - Switch construction - Google Patents

Description

June 9, 1942.

t N. c. SCHELLENGER SWITCH CONSTRUCTION.

Original Filed May 2, 1938 2 Sheets -SI 'i eet l i I J h z 31, I :F M30 June-9, 1942. H EN ER. 2,286,163

SWITCH CYOINSTRIUCTION O riginal F 'iled Ma a, 1938' 2 sheetsesheet 2 Viscous awawm N mm 555171 5 2151" Wm 4 Patented swrrcu consrauc'non Newton Schellenger, El Paso, Ten, assignor to 0 Telephone Supply Company, Ind, acorporation oI-Indiana Original application my .2, 1938, semi No. 205,399, now Patent No. 2,211,706, am sum 13, 1940. Divided and this 17; 1940, Serial No. 340,970

This invention relates to electric switches and refers particularly to small switches of the type illustrated in the copending application of Newton C. SchellengenSerial No. 205,399, filed May 2, 1938, which has matured into Patent No. 2,211,706, patented August 13, 1940, of which this application is a division.

These switches generally comprise spaced stationary contacts mounted on a suitable base of insulating material and adapted to be electrically bridged by a contactor movable across the base. Because of the character of their use, these switches must be capable of satisfactory operation throughout a relatively long period of service involving a great many makes and breaks.

To this end, utmost care is exercised in the design of the switches to insure against mechanical wear, and to minimize destructive arcing effects, the switches are generally or the snap action type.

application June ing the switch closed;

Figure 5 is a detail sectional vi through However, notwithstanding their snapaction,

one of the most troublesome aspects or the problem of insuring satisfactory operation over along period 0i. service is contact ting and corrosion.

This objection can be reduced materially by Figure 2 is a longitudinal sectional view through the combined switch and volume control Figure 3 is a sectional view through Figure 2 on the plane of the line illustra the switch in open position; 1

Figure 4 is a view to Figure 3 but show- FigureB on the plane of the line and Figure 6 is a detail sectional view taken through Figure 3 on the plane of the line Referring now particularly to the accompany ing drawings, in which'like numerals indicate like parts, the numeral 5 cites generally a switch of the type with which this invention is directly concerned.

As illustrated in Figures 1 and 2, the switch may be mounted on the back or avolume control designated. generally. bythe numeral 6 to be operable by the volume control shalt I. In the present instance, the switch and volume control combination are of the doughnut" type failure due to pitkeeping the contacts lubricated. It is, therefore,

an object of this invention to provide an expedient manner of maintaining asupply of lubricant adjacent to the contacts to be fed thereto as the lubricant on the contacts is burned off in the operationoi the switch.

More specifically itis an object of this invenwherein the operating shaft entirely there-' through.

It is to be understood, however, that the invention is not limited to switch and volume control combinations such as shown, but is applicable to any switch structure of this general class.

Inasmuch as the volume control forms no part of this invention, it has not been-specifically illustrated, suiilce it to saythat the control comtion to provide a switch of the 'character iescribed which incorporates lubricant containing;

pockets or wells in the base on whichthe stationary contacts are mountedand also in the switch arm which carries the contactor.

With the above and other objects in view,

'whichwill appear as the descriptionproceeds this invention resides in the novel construction,

combination and arrangement or parts substantially as hereinafter described,- and more parprises a base 0 having a resistor 9 mounted thereon.- An appropriate contact shoe (not shown) is arranged to traverse the resistor. The contact shoe-is carried by a rotatable contact member ll drivingly connected'with the shaft I to be operated thereby.

A cup-shaped metalhousing ll positioned over the variable resistor mechanism 01' the volume ticularly defined bytheappended claims, it beingunderstood that such changes in the'precise embodiment of the hereindisclosed invention may be made as comewithin the scope of the claims.

The accompanying drawings illustrate one complete example of the, physical embodiment of the invention, constructed in accordance with the best mode sofar devised for the practical .ap-

' plication of the principles thereof, andin which:

Figure 1 is a rear view of a combined switch and volume control of the type with which this invention is particularly concerned;

control and connected to its base I has theswitch 5 mounted on its end wall II. The switch mechanism is enclosed within a suitable housing comprising a list base ll of insulating material and a cylindrical metal side .wall I It, the enclosure being completed by the wall l2. The base It and also the wall I! are apertured to allow the operating shaft to pass centrally through the switch.

The base I 3 mounts two spaced stationary contacts l5 and It which are adapted to be electrically bridged by a contactor l1. These stationary contacts consist of the inturned ends of terminal members I and ",respectively. The, terminal members are secured to the base by .rivets or other fastenings III, with their inturned ends passing through correspondingly shaped openings 2| in the insulating base. In this manner the combined terminal members and contacts are secured against rotation about their fastening rivets 20.

The movable contactor ll consists of a strip of resilient fiat stock bent to a substantially serpentine formation which provides spaced contact portions 22 and 23, respectively engageable with the stationary contacts l and l 6. Between these contact portions, the contactor I! has an attaching lug 24 projecting from one edge thereof to engage in an opening 25 in a movable switch arm 26. c

The opening 25 is somewhat larger than .the lug 24 to give the contactor a degree of freedom with respect to the switch arm and allow its contact portions to adjust themselves to their respective stationary contacts, relative motion between the contactor and switch arm being limited by a second lug 21 on one end of the contactor engaging in a notch 28 in the adjacent edge portion of the switch arm.

The switch arm 26 is pivoted on a post 29 secured to the base l3 to oscillate across the base in a switch closing and opening motion. Also pivoted on the post 29 is a switch actuator 30 which is connected with the arm by a spring 3| so that a toggle structure is produced through which the switch arm and consequently the contactor is snapped from one position to the other as the actuator 30 is rocked about the post 28 between its limits of motion. Switch actuating motion is imparted to the actuator by a driving lug 32 movable with the contact member ID of the volume control.

It is to be observed that the contacts l5 and it are so disposed as to cross the .paths of the contact portions 22 and 23 at the same angle so that as the switch is closed, the contactor.engages the contacts with a wedge-like action. This, together with the resiliency of the contactor and its relatively loose connection with the switch arm, insures good contact and uniform contact pressure at both contacts.

Good contact between the stationary and moving contact surfaces throughout a long period of service, depends, however, upon the maintenance.

of smooth clean contact surfaces. A slight degree of relative sliding motion between the contacting surfaces is necessary to insure the desired condition; and while the arrangement of the contacts and the resiliency of the contactor go a long ,way toward insuring this optimum switch action, it has been found that the useful life of the switch can be materially prolonged by maintaining the contact surfaces adequately lubricated.

. To this end, the base I3 is providedwith lubricant pockets or wells 33 in the form of enlargements of its openings 2| on the inner sides of the contacts I5 and I6. These pocketsor wells are filled with a suitable viscous lubricant such as Vaseline during assembly of the switch to provide a reservoir of lubricant directly adjacent to the contacts. The outer ends of these openings are closed by the flat walls l8 and l3 ,of the terminal members.

Lubricant reservoirs are also provided adjacent a to the contact portions 22 and 23 of the contactor. These reservoirs consist of openings 34in the switch arm 26 directly adjacent to the con-" tact portions as clearly shown in Figures 3 and 4. The openings 34, like the pockets or wells 33, are filled with viscous lubricant, such as Vaseline.

The close proximity of the lubricant reservoirs to the contacts insures the lubricant working material; a stationary contact member mounted on the base, said contact member having angularly disposed contact and terminal portions the former fitting against the outer face of the base and the latter projecting through a hole in the base and being exposed on the inner face of the base; a contactor movable to and from engagement with the stationary contact member; and means for providing lubricantto the contacting surfaces of the stationary contact member and the contactor comprising, a hole through the base adjacent to the contact portion of the stationary contact and under the terminal portion thereof so that said hole and the terminal portion covering it provide a lubricant reservoir opening to the inner face of the base adjacent to the contact portion, and lubricant in said reservoir.

2. In an electric switch: a base of insulating material; a stationary contact member mounted tion comprising an enlargement of the hole through which the contact portion projects, said enlargement of the hole being under the terminal portion of the contact member so as to be covered thereby and said hole and terminal portion coact tot form a lubricant reservoir bounded at one side by the contact portion, and lubricant in said reservoir; a movable contactor cooperable'with the stationary contact member; a' carrier for the contactor; means connecting the contactor to the carrierin a manner allowing limited motion of the contactor with respect to the carrier; and means for supplying lubricant to the contact surface of the contactor and between the contactor and the carrier comprising a hole in the carrier adjacent to the contact portion of the contactor, and lubricant in saidhole.

' NEWTON C. SCHELLENGER.

Images