US1273754A - Rheostat. - Google Patents

Description

F. EMBERGER.

RHEOSTAT.

APPLlCATION FILED SEPT. 6. I91]- 1 ,27 3 ,754:. Patented July 23, 1918.

FERDINAND EMBERGER, or BOARDMAN, OREGON.

. RHEOSTAT.

Specification of Letters Patent.

Patented July 23,1918.

Application filed September 6, 1917. Serial No. 190,049.

To all whom it may concern:

Be it known that I, FERDINAND EMBERGER, a citizen of the United States residing at Boardman, in the county of Morrow and State of Oregon, have invented new and useful Improvements in Rheostats, of which the following is a specification.

The invention relates to improvements in electric switches and seeks to provide, as its principal purpose, a switch of this character for use in connection with incandescent electric lamps, whereby the luminosity of such lamps may be varied.

As a further purpose, the invention is designed to comprise a switch in conjunction with a rheostat, and to inclose the whole within a suitable casing which is adapted to be carried by the flexible wire which carries the lamp which the switch controls, it

being the object to place the switch abovethe lamp and to connect it in circuit therewith by tapping one of the two conductors which feed the lamp.

It is a further purpose of the invention to provide a switch of this character which may present a neat appearance, which may be easily and cheaply made, and which will effectively perform its function.

Other and further objects will be made apparent as the detailed description of the device progresses. 4

- While illustrated in but one form, it is to be understood that the invention is not to be restricted to this particular form. An actual reduction to practice may make manifest certain changes or alterations, and these the right is claimed to make, in so far as they may be compatible with the'spirit of the ap ended claim.

n the accompanying drawings Figure 1 is an elevation of the invention,

Fig. 2 is a section on the line 2-2 of Fig. 1.

Fig. 3 is a section taken centrally through the device at right angles to the section of Fig. 2, but the upper portions of the casing are omitted in this figure.

Fig. 4 is a perspectlve view of the switch key and its attendant contacting arm.

Referring to the drawings, there is shown a cylindrical casing which comprises the sections 1 and 2 that are attached together by means of screws 3, the latter being tangentially disposed with reference to the cylindrical surface and passing through body holes in the section 2 and entering threaded holes in the section 1. The cylindrical cas ing is provided at either end with ornamental projections 4 formed half on the section 2 and half on the section 1.

At approximately the center of the cylindrical casing-provlsion is made for the resistance device and for the operatin arm of the switch, a substantially semi-circular recess 5 being formed in the casing and existing partly in the section 1 and partly in the section 2 and entrance to this recess is had through cylindrical holes 6 which open at either end of the casin and are centrally disposed with reference 1; ereto, so that they may pass through ornamental rojections 4 which constitute suitable bushings for the flexible electric conductors 7 that enter and leave the casing.

At the center of the semi-circular recess 5, an angularly movable stem 8 is mounted, this stem having one end entering a cylindrical depression formed in the section 1 but having the body portion passing through a cylindrical hole formed in the section 2 on the outside of which it terminates in a key or thumb piece 9. A contact member 10 is secured to' the section 1 in the recess 5 by means of a screw 11 and this contact member has one end in surrounding relation to the stem 8 and the other end provided with a binding post 12. Oppositely disposed from the contact member 10 there. is a resistance device 13 which is provided with a suitable binding post 11 which is conveniently held in the recess 5 at the point where one of the holes 6 enters the latter. sistance device 13 is provided with a plurality of arcuate arms, no two of which are of the same radius but all of which are formed to curves generated with stem 8 as a center. The center arm 15 of this resist ance device is the longest of the arms. The two arms 16 immediately adjoining this arm on either side are somewhat shorter than This re-.

the arm 15 but on the other hand some sulating material and may be either fiber or hard wood. Those parts of the device which are of necessity insulated from each other require no other insulation than the material of the casing on which they are mounted. Spaced away: from the extremity of the arm 15, there is a dead contact 21 on which the switch arm 18 is designed to rest when the circuit is open and this arm is precluded from angular movement further tnan this dead contact by'means of a pin 22 against which the side edge of the switch arm contacts.

'When the two sections of the casing are attached together, as shown in the drawings, the stem 8 is prevented from longitudinal movement by having one end of the hub 19 abut the inner face of the section 2 and the bottom face of the switch arm 18 abut the top face of the contact member 10. The stem 8 is permitted to turn, however, and to move the switch arm 18 over the several. arms 15, 16 and 17 of the resistance device These arms 15, 16 and 17 are designed to be made of any suitable high resistance material and their varying lengths give them correspondingly varying resistance values.

Since the resistance of an electric conductor varies directly with its length the resistances of the arms 15, 16 and 17 are proportional to their lengths. Therefore the arm 15 has the greatest resistance, the arms 16 less resistance'than the arm 15 and the arms 1? less resistance than the arms 16. This arrangement has the effect of reducing the resistance interposed in the circuit as the switch arm 18 moves from the arm 15 to the arms 16 and then to the arms 17.

The flexible electric conductor 7 previously referred to is of the duplex type carrying wires 23 and 24: which are connected to opposite sides of an electric supply source, and transmit the current therefrom to an incandescent lamp or other electric apparatus with which the present device is used. The conducting wire 23 is severed and one of its ends is connected to the binding post 14 and the other end to the binding post 12, thus placing the present device in circuit with the apparatus which it is presumed to control.

It will be observed that when the switch arm 18 rests on the dead contact 21 the circult is opened at this point. When the switch arm 18 passes on to the arm 15, the circuit is closed, but through this long arm 15 whose resistance is sufficient to dim an incandescent light, or to cut down the speed of a motor which the device may control. As the switch arm 18 passes on to the arms 16, the resistance is lessened and the conductivity increased as a result of the resistance units being thrown in parallel, 'lherefore, the incandescent lamp which it is presumed is in circuit will burn brighter than previously, TWhen the switch arm 18 passes on to the arms 17 it will have contact with all of the arms, resulting in another reduction of the resistance and increasing the luminosity of the lamp. Finally, when the switch arm 18 is in alinement with a binding post 1%, the resistance becomes practically nil, and the lamp burns with full luminosity.

What is claimed is 1:

In a rheostat, a cylindrical casing made of insulating material comprising two sections detachably connected, the said casing having a central interior recess and holes opening cess which holes and recess are formed partly in one section and partly in the other, a resistance device contained within the central recess of the casing and attached to one of the sections thereof, the said resistance device comprising a plurality of arcuate arms concentric with each other but of varying lengths, a switch arm slidably movable over the arcuate arms, so that it may contact with one or several of said'arms, a con tact member secured to one of the sections of the casing and within the central recess thereof. an angularly movable stem fixed transversely in the casing, and binding posts attached to both the contact member and the resistance device, the switch arm being carried by the stem, the contact member having one end in surrounding relation to the stem and one face in frictional contact with the switch arm.

In testimony whereof I afiix my signature.

FERDINAND EMBERGER.

from both ends into the retill

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