US1195660A - Rheostat - Google Patents

Description

H. L. DODGE.

RHEOSTAT.

APPLICATION FILED MAR. I5, 1915.

1 1 95,660. Patented Aug. 22, 1916.

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HOMER L. DODGE, OF IOWA CITY, IOWA.

RHEOSTAT.

Specification of Letters Patent.

Patented Aug. 22, 1916.

Application filed March 15, 1915. Serial No. 14,537.

T all whom it may concern.

Be it known that I, HOMER L. Doncn, a citizen of the United States, residing at Iowa City, in the county of Johnson and State of Iowa, have invented a new and useful Rheostat, of which the following is a specification.

This invention has reference to rheostats, and its object is to provide a rheostat, as a unitary structure, whereby either the current or the voltage of an electric circuit may be controlled at will.

In accordance with the present invention an adjustable rheostat is provided, which rheostat may follow the lines of any suitable approved form of rheostat, and in connection with such an instrument there is provided the usual slider, or more than one slider where such an arrangement may be desirable.

At the full-resistance end of the rheostat a switch is provided, whereby the rheostat may be connected across the circuit without disturbing the series connection of the rheostat.

By this means the same instrument once connected in the circuit provides for obtaining any desired current within the limits of the source, or any desired voltage within the limits of the source.

The invention is designed particularly for laboratory or class work, but is useful in other connections.

The invention will be best understood from a consideration of the following detailed description, taken in connection with the accompanying drawings forming a part of this specification, with the further understanding that while the drawings show a particular form of the invention, the latter is not confined to any strict conformity with the showing of the drawings, but may be changed and modified so long as such changes and modifications mark no material departure from the salient features of the invention.

In the drawings :Figure 1 is a plan view with parts in diagram illustrating a rheostat constructed in accordance with the present invention. Figs. 2 to 6 are diagrams illustrating various adaptations of the invention.

Referring to the drawings there is shown in Fig. 1 a base board 1 which may represent any suitable support, and on this base board there is a rheostat having a resistance element 2 conventionally illustrated in diagram. Capable of moving over the reslstance 2 which may be taken as. of the customary form of a coil of resistance wire,

part of the coil 2 along the length thereof to cut in or cut out resistance as may be desired.

One end of the resistance 2 is connected by a conductor 5 to a binding post 6 and alongside of the binding post 6 is another binding post 7. The two binding posts 6 and 7 may be conveniently located near one end of the base board 1, while near the other end of the base board are two other binding posts 8 and 9, respectively. These binding posts are designed to receive conductors whereby the rheostat may be included in a suitable circuit. The binding posts 6 and 7 are designed to receive line wires 10, 11, respectively, and for convenience the word Line may be stamped or otherwise produced upon the base 1 adjacent to the bind ing posts 6 and 7.

The binding posts 8 and 9 are designed to receive conductors 12, 13, leading to the load, and adjacent to the binding posts 8 and 9 the word Load may be produced upon the base 1 for the convenience of the operator.

The binding post 7 is connected by means of a conductor 14: to one side of a fuse 15 which may be mounted on the base board 1, and the other end of the fuse is connected by a conductor 16 to the binding post 8, and this conductor is also connected at an appropriate point to one side of a switch 17, the other side of which switch is connected by a conductor 18 to that end of the resistance 2 remote from the conductor 5. The switch 17 is provided with a switch arm 19 by means of which the switch may be opened and closed at the will of the operator. While the switch 17 is shown as of the familiar jack knife type, it will'be understood that the switch is to be taken as indicative of any suitable type of electric switch and the invention is not to be considered as confined to any particular construction of electric apparatus in such respects.

The

ductor guide bar 4 is connected by a conto the binding post 9.

Let it be assumed that the line conductors 10 and 11 are connected to a suitable source of current, and that the switch arm 19 is open. Furthermore, let it be considered that included in circuit with the conductors 12 and 13 is an appropriate load represented in Figs. 2 to 6 as electric lamps 21, but which load is not Confined to any particular type of translating device or devices.

if there be a certain voltage upon the line 10, 11, and the slider 3 be so located with respect to the resistance 2 that the latter is all cut out, the current delivered to the conductors 12 and 13 will be equal to the voltage divided by the resistance of the load, as is, of course, well known, and the current may be reduced from the maximum thus stated, to any minimum within the range of the resistance 2 by moving the slider 3 along the resistance to an appropriate point.

Again let it be assumed that there is a certain voltage on the line 10, 11, and this may be the same voltage as first assumed. If the slider be at the beginning or zero end of the resistance and the switch arm 19 be closed, the full voltage will be delivered to the conductors 12 and 13, and this also means full current as determined by the resistance of the load. If, now, the slider 3 be moved along the resistance 2 the current will divide, part passing by way of the slider 3 to the bar 1, and thence to the conductor 13, and part passing entirely through the resistance to the conductor 18, through the switch 17, and by way of the conductor 16, fuse 15 and conductor 14 to the other side of the main line. The current which has passed to the load returns by conductor 12 to the switch 17 and there joins the current flowingby way of conductor 18 and switch arm 19 to the main 11. The result of this is that there is a drop of potential in the load conductors 12 and 13, and the voltage therein will be approximately proportional to the ratio of the lengths of resistance on opposite sides of the slider 3. In this manner even by the employment of a single resistance and a single slider, the operator has at command any current or any voltage within wide limits, and this is particularly valuable in the class room, or in the laboratory and under certain circumstances may be of value elsewhere.

A particular feature of the present invention is that with one instrument connected up in the circuit and without the necessity of making any changes whatever in the line connections, the operator may by the simple expedient of opening or closing a switch and adjusting the rheostat as needed, obtain any voltage from zero to maximum within the range of the instrument and any current from zero to maximum within the range of the instrument, and, of course, of the source of current charging the circuit.

In Figs. 2 to 6 twin rheostats comprising two resistances 2 are disclosed. In Fig. 2 two sliders 3 are provided and one of the resistances 2 is connected across the line conductors 10, 11 by a switch 17, while the other electrical conductors correspond to similar ones of Fig. 1 and are similarly indicated by reference numerals.

in Fig. 2 the slider bar 4 of one of the resistance coils 2 is connected up to one end of the other resistance 2 and the slider bar 1 of the second resistance 2 is connected l a conductor 20 to the binding post as in Fig. 1. The arrangement of F differs from that of Fig. 2 in that the resistance coils 2 are connected up in series with the switch 17 in position to couple directly to one of the slider bars 4-, while the other slider bar is connected as before by the conductor 20 to the binding post 9.

The arrangement of Fig. 1 differs from that of the preceding figures in that the two slider bars 1- are connected together in series, with the switch 17 arranged to couple one of the resistance coils 2 across the line, while the other resistance 8 is connected by a conductor 20 to the binding post 9. In the arrangement of Fig. 5 one of the resistances 2 is connected in series with the slider bar 4 of the other resistance 2 and the sec ond resistance 2 is connected by a conductor 2O to the binding post 9, as in Fig. a. The switch 17 is arranged to connect with the slider bar a of the first resistance 2 In Fig. 6 the two resistances 2 are connected together in series by a conductor 20" with one resistance 2 connected to the binding post 6 and the other resistance connected to the binding post 9 by a conductor 20 There is provided a single slider bar a with a slider 3 having two contacts for simul taneous engagement with both coils 2*: The switch 17 is arranged to connect the conductor 2O with the conductor 16 as before.

These examples are suflicient to illustrate the various ways in which the combined voltage and current rheostat of the present invention may be arranged, and it is deemed unnecessary to multiply examples in order to demonstrate the relatively wide range of variations of which the present invention is susceptible.

What is claimed is 1. A unitary current controlling device comprising a base or support, line and load receiving terminals on the base, resistance means on the base connected at one end to one of the terminals on the line side of the device, a direct connection on the base from the other terminal on the line side to one of the terminals on the load side of the device, a switch between the other end of the resistance means and the direct connection between the load and line sides of the device, and means connected to the other terminal on the load side of the device and adjustable with relation to the resistance means to include more or less resistance in circuit, the switch and the last-named means being individually operable.

2. A combined voltage and current rheostat comprising a unitary structure consisting of a base or support, a resistance and means for varying it mounted on the base, means also on the base for making line and load connections to the rheostat, and means on the base for connecting the resistance at will across the means for making line connections, the means for varying the resistance and the last-named means being independently operable, whereby variations in voltage may be obtained without disturbing the connections of the rheostat for current regulation.

3. An instrument for obtaining variations in current or voltage at will, comprising a suitable base orsupport, a resistance and means for varying it mounted thereon,

means for including the variable resistance in series between a source of current and the load, and means individual to the resistance for cutting said resistance into and out of shunt relation across the circuit at will, whereby to provide for obtaining variations of voltage when the resistance is in such shunt relation.

4. A means for obtaining variable current or variable voltage at will, comprising a single instrument having a resistance and means for varying it, said single instrument also including connecting devices for coupling the variable resistance in a circuit to be controlled, other connecting devices for coupling the resistance to a source of supply, and a switch for connecting the variable resistance across the source of supply, the switch and the means for varying the resistance being separately operable.

In testimony that I claim the foregoing as my own, I have hereto afiixed my signature in the presence of two witnesses.

HOMER L. DODGE.

Witnesses:

F. C. BROWN, P. T. MCNALLY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C.

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