US1585214A - Rheostat arm - Google Patents

Description

May 18 1926.

M. A. SZUKALSKI ET AL RHEOS TAT ARM Filed March 26, 1925 MVJ Patented May 18, 1926.

UNITED STATES MARIAN A. SZUKALSKI AND MARIAN F. SZUKALSKI, J 3., OF MILWAUKEE, WISCONSIN.

1,585,214 PATENT OFFICE.

RHEOS'IAT ARM.

Application filed March 26, 1925. Serial No. 18,417.

This invention relates to rheostats, and is particularly directed to a rheostat arm..

In rheostats in which a traveling arm passes over a resistance, diiliculty has been experienced in maintaining a positive electrical contact between the arm and the resistance, and further due to irregularity in the manufacture of resistance such as the coil wire employed in rheostats in radio apparatus, a scraping or rough, uneven action results.

This invention is designed to overcome the above noted defects, and objects of the invention are to provide a rheostat in which a positive electrical contact is insured at all positions of adjustment between the arm and the resistance, and in which a free and easy travel of the arm is insured irrespective of variations in the surface of the resistance due to errors in manufacture.

This invention, although applicable to rheostats in general, is particularly applicable to rheostats employed with radio apparatus in. which the scraping and uneven action is highly detrimental, and such invention, therefore, provides a rheostat which may be successfully used with radio apparatus to secure the exact adjustment desired without the presence of an irregular or jerky action. 7

An embodiment of the invention is shown in the accompanying drawings, in which Figure 1 is a bottom plan View of one form of rheostat showing the arm in posi- .tion.

Figure 2 is a transverse sectional view 3 throu h the rheostat.

sleeve 4 and is in intimate contact with the.

sleeve throughout its extent.

It is to be noted that the rear end of the adjusting spindle 6 passes through the hub 7 of the arm 8, such hub being provided with a set screw 9 to lock it to the spindle.

Further, it will be noted that the spindleet is electrically connected to the strap 10 which is secured to one of the outlet or terminal ends or connectors of the rheostat, the

other terminal of the rheostat being connected to the other end of the resistance 3 in the usual manner.

A convenient way of making the arm 8 is to give it a 'platelike formation and to rigidly secure it to the hub 7 in any suitable manner. This arm is provided with upstanding bearings 11, 12 and 13 which receive a small shaft 14, such shaft extending axially of the arm. It is tobe noted that the arm 8 is cut away adjacent its forward end, as indicated at 15 and that a contact roller 16 is rigidly secured to ,the shaft 14 and operates through the cut out 15, such roller contacting with the resistance 3. It is to be noted, of course, that the arm 8 is springy and is given a slight tension towards the resistance 3 to press the roller against the resistance element.

In order to insure a permanent electrical connection between the roller 16 and the shaft 14, an elongated helical spring 17 has its outer end rigidly secured to the shaft and its inner end rigidly secured, as indicated at 18, to the arm 8.

In using the apparatus, the roller travels over the resistance element and in one direction of rotationwinds the spring 17 slightly. This spring, however, is of sufficient length to permit this winding without undue stresses. Obviously, when the arm is rocked in the reverse-direction, the spring is unwound to its original state. However, at all times, the roller is permanently electrically connected to the arm 8, irrespective of its rotary motion.

If desired, this inventive idea may be carried out further by providing a similar spring or connecting member 19 permanently connecting the hub 7 with the stationary arm 10.

It will be seen, therefore, that a rheostat arm construction has been provided in which a roller is employed to freely pass over the irregularities in the resistance element, and in which the roller is permanently electrically connected with the arm irrespective of its position of adjustment.

Although the invention has been described in considerable detail, it is to be understood that the invention may be variously embodied and is, therefore, to be limited only as claimed.

We claim:

1. A rheostat arm comprising an elongated member adapted to be connected to a roller rigidly mounted upon said shaft ad jacent its outer end, a helical spring loosely surrounding said shaftand having one end rigidly secured thereto and its other end rigidly secured to said arm:

2. A rheostat comprising a body portion, an elongated resistance element carried thereby, a movable rocking arm pivotally carried by said body portion, a shaft carried by said arm, a roller rigidly secured to said shaft adjacent the outer end. of said arm and contacting with said resistance, a flexible electrical conductor rigidly secured at one 'end to said shaft, and at its other end 'to said arm, and a second flexible electric conductor having one end rigidly connected to the inner portion of said arm, a

terminal member rigidly connected to the other end of said second flexible conductor,

and a second terminal member connected to one end of said resistance.

3. A rheostat comprising a body portion, a--resistance element carried by said body portion, an arm movably supported by said body portion, a shaft'revolubly carried by said arm, a roller contacting with and adapted to travel over said resistance element, said roller being rigidly secured to said shaft, and a flexible electrical conductor having one end rigidly connected to said shaft and adapted to be rotated therewith and having its other end rigidly fastened to said arm.

In testimony that We claim the foregoing We have hereunto set our hands at Milwaukee, in the county of Milwaukee and State of lVisconsin. I

MARIAN A. SZUKALSKI. MARIAN F. SZUKALSKI, J n.

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