Sliding contact unit for potentiometer

July 1, 1969

E. A. HANSON 3,453,584

SLIDING CONTACT UNIT FOR POTENTIOMETER

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United States Patent Office 3,453,584

-----------------—__________________ Patented July 1, 1969 „ , 3,453,584 ^Sr i^DIi^N? CONTACT UNIT FOR POTENTIOMETER

Earl A. Hanson, Ridgway, Pa., assignor to Stackpole Carbon Company, St. Maiys, Pa., a corporation of Pennsylvania ^F

Filed June 21, 1967, Ser. No. 647,661

US CI 338 m ^{CL H01c 5/02}’ ^1/12

C.S. CI. 338—183 3 claims

ABSTRACT OF THE DISCLOSURE

A sliding contact unit for use between parallel collector and resistor strips includes a slide provided at one side with means for moving it endwise, and an open frame projecting from the opposite side. Mounted in the frame is a wire coil that projects laterally from it to form a bridging contact.

It is among the objects of this invention to provide a sliding contact unit which is simple in construction and quick and easy to assemble.

The preferred embodiment of the invention is illustrated m the accompanying drawings, in which

FIG. 1 is a front view of a potentiometer;

FIG. 2 is a side view thereof with part broken awaw and ” _TTT^FI9'^{3 is an} enlarged cross-section taken on line III— III of FIG. 2.

. Referring to the drawings, the long rectangular housing 1 ot a potentiometer may be formed from a molded plastic or other suitable rigid material. The housing preferably is made from two molded half sections that have meeting edges extending from front to back across the end walls of the housing and lengthwise along its back or base. The half sections are joined together in any suitable manner, such as by adhesive for example. The front or top of the housing is provided centrally with a slot‘2 ^f» ^iis “> >««· «“«Η 5Slidably mounted in the slot for movement lengthwise oi the housing is a rectangular slide 3 that has laterally opening grooves 4 in its opposite sides receiving the side walls of slot 2 to hold and guide the slide. The outer 45 side of the slide is provided with a projection or knob 5 tor moving the slide endwise back and forth along the slot. A. metal collector strip 7 and an electrical resistor ® mounted inside the housing at opposite sides thereof. The collector strip is provided with an integral 50 terminal 9 that extends through the back of the housing while each.end of the resistance strip is connected to a metal terminal 10 likewise extending through the back

It is a feature of this invention that the slide is equipped with, means for quickly attaching a bridging contact to it 55 so that the assembly will form a sliding contact unit. Acrec10 cordingly, an open frame 12, integral with the slide, pro^J„^e„^Ctl^frOm-^thcT^^e?^{f the slide} °PP°^site its actuating knob as shown in FIG. 2. Thus, the frame is entirely inside of the po tentiometer housing. The plane of the frame extends lengthwise of the slide and is parallel to the collector and resistor strips. The frame preferably is ^the ΐ^η·^{Π6Γ Side of the sIide} Arming one side of the frame. Disposed in this frame is a wire coil 13 the axis of which is perpendicular to the slide. The coil IS held in place by a pair of projections 14 integral with the Anrk ^pr°^Jcc^{tmg & short} distance into the opposite λ ^thf ^CM ‘ ^M°,^{St su}'^tably>^the Projections are integral th the frame and preferably are tapered toward each other as seen in FIG. 2 of the drawings to facilitate insertion of the spring m the frame. The coil projects from ?nn°^S1t^{te S1}f^6S °^{f tbe} J^{rame and} slidingly engages both the collector strip and the resistor strip, thereby forming a bridging contact between them. The convolutions of the coil are spaced apart sufficiently to have permitted it to be compressed axially and inserted projections 14 and wtA f®^leased> whereupon it is expanded into engagement with the frame. This manner of attaching the coil to the slide in very simple and rapid, thereby reducing the cost of the potentiometer.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment.