US1797370A - Thermo-electro-responsive device - Google Patents

Description

I Mmh24, 1931. H. E. RUFF I 1,797,370

THERMO- ELECTRO-RESPONS IVE DEVICE Original Filed May 20, 1926 2 Sheets-Sheet l iii lifi

March 24, 1931. H4 1:. RUFF 1,797,370

THERMO-ELECTRO-RESPONSIVE DEVI CE Original Filed May 20, 1926 '2 Sheets-Sheet 2 nvcnrct A EEBa ET E. EUPP Chrome Patented Mar. 24, 1931 UNITED STATES PATENT OFFICE HERBER'F E. RUPP, OF MANSFIELD, OHIO, ASSIGNOR TO THE OHIO BRASS COMPANY, OF MANSFIELD, OHIO, A CORPORATION OF NEW JERSEY THERMO-ELECTRO-RESPONSIVE DEVICE Original application filed Kay 20, 1926, Serial No. 110,411. Divided and this application filed December My invention relates to a thermo-responsive device for controlling the flow of currents and can be used as a switch or to control other mechanism. I

I have shown the device as applied to the operation of a rotatable switch, but for the sake of simplicity, I switch in detail, as the device can be used to controlthe operation of a rotary or other type of switch, as for instance, the operation of the rotary switch as shown in detail in copending application, Serial No. 102,653, filed April 17, 1926, in the name of Edgar D. Moore, with which I' am familiar.

This application constitutes a division of my co-pending application, Serial No. 110,- 411, filed May 20, 1926, for a thermo-electroresponsive device.

I have devised a thermo-responsive device which can be used alone as a switch or in combination with electrically controlled mechanism, which in turn my invention will control, and which is new and novel and the adjustment of which is not affected by changes in temperature of the surrounding atmosphere.

One of the objects of my invention is to provide a mechanism which can be connected to a circuit, and when the current flowing in the circuit suddenly exceeds a predetermined amount the mechanism will operate to open the switch.

Another object of my invention is to provide in the mechanism a thermo-responsive device which acts as a switch to control the operation of the mechanism when the current flowing in the circuits exceeds a predetermined amount for a predetermined time.

Another object is to provide a thermo-responsive device comprising a plurality of thermal elements in which all the thermal elements are affected by a common means and one of the elements is affected by other independent means.

A further object is to provide a means of protecting an electric translating device from a dangerous rise in temperature.

Another object of my invention is to provide means for rendering the thermo-responhave not shown the 1926. Serial No. 154,443.

with a rotary switch, as set forth above, for I controlling the circuits leading to electrically operated translating devices such as motors,

lights, etc., it provides a means of protecting the translating device from sudden overloads and also from loads sufficiently high to cause a dangerous heating of the translating device when not sufliciently high to cause the overload to operate. In other words, it

will permit the translating device to carry its maximum safe load.

I have shown certain parts of my invention in the attached drawing in schematic form, as the construction is simple and well known to those skilled in the art, and to make the disclosure in other form than shown, it is believed would merely complicate the understanding of the invention.

My invention resides in the new and novel construction, combination and relation of the various parts herein described and shown in the accompanying drawing.

- In the drawings:

.Fig. 1 is a plan view, partially schematic.

Fig. 2 is an end view of Fig. 1.

Figure 3 is a right-hand side view of Fig. 1.

Fig. 4 isa left-hand view of Fig. 1.

Fig. 5 is a detail of the thermostatic control with a portion broken away.

Fig. 6 is a sectional view on the line 66 of Fig. 5 to show an adjustable member on the thermostatic control.

Fig. 7 shows one of the elements of the thermostatic control.

Fig. 8 shows my device as applied to a rotary switch, referred to before, and to a translating device.

Fig. 9 shows a modification of the relay construction shown in Fig. 1.

In the preferred construction of my relay, I employ a base member 1, preferably of insulating material. Mounted upon the base 1 is amagnet M, which does not differ in principle from other well known magnets, but which comprises a core 2, end members 3 and; secured to the core member 2 by means of screws and secured to the base 1 by means of the screws 5. The end members 3, and 4 may both be made of iron, but the end member 3 may be made of other material. The armature 6, w hich is also of iron and movably secured to the end member 3 by means of the spring 7, it attracted by the end member 4. The base 1 has mounted thereon the terminal posts 8, 9, 10 and-11.

The core 2 is provided with a coil 12 having one terminal connected to the post 8 by the conductor 13 which is preferably concealed within the base 1. The other end of the coil 12 is connected to the post 10 by means of the conductor 14, also preferably enclosed within the base. The coil 12, it will be noted, isconnected in series in the circuit between the posts 8 and 10, therefore, all current flowing through the circuit connecting the posts 8 and 10 will flow through the coil 12. This coil I prefer to construct of copper and of reasonably low resistance in order to cut down resistance losses, as it forms a part of the main circuit conducting current whenever the device is in use.

The core 2 is provided at each end with insulating discs 15 and surrounding the core is also insulating material to maintain insulationbctween the coil 12 and the adjacent metal pa rts. This construction is well known to those skilled in the art.

Mounted on the base 1 is a thermostatic responsive device T which comprises an insulating member 16 secured to metallic standards 17 and 17 by means of the screws 18 and 18'. Mounted on the insulating member 16 is a bi-metal thermostatic element 19 composed of two dissimilar metals whose temperature co-eflicients are different. This bimetal element is well known in the trade. The element 19 is secured to the insulating member 16 by means of the screw 20 and at its distant end is a contact element 21 secured thereto which may be of metal, but preferably of carbon.

Also mounted on the insulating member 16, but spaced from the element 19, is a U-shaped bi-metal thermostatic element 22 (see Fig. 7).

This element is provided with contacts 23 and 23, which are mechanically and electrically connected to the standards 17 and 17 respectively, by being interposed between such standards and the insulating member 16 and held in position by the screws 18 and 18. At the distant end of the element 22 is a contact member 24 adapted to engage with the contact member 21.

The contact 23 of the element 22 is connected to the post 9 by the conductor-25. The contact 23 is connected to the post 11 by means of the conductor 26. From this it will be seen that the U-shaped bi-metal thermostatic element is connected in series with the circuit connecting the posts 9 and 11 and,

- therefore, the current flowing through the which flows through the coil 12 will also flow through the ment 22.

The magnet core 2 is provided with an auxiliary winding 27 which has one terminal connected to the conductor 14 through the U-shaped thermostatic eleconductor 28 and the other terminal being connected to the thermostatic element 19 through the conductor 29 and the screw 20. It will be noted that under normal conditions with the contacts 21 and 24 separated that no current would flow through the coil 27, but should the contacts 21 and 24 be brought into engagement then the coil 27 will be connected between two main circuits connecting the posts 8--10 and 9-11. It will also be noted that when the contacts 21 and 24 are connected together that the two coils 12 and 27 will be in series and connected across the opposite circuits. In other words, the main circuits will be connected together through the coils 12 and 27 in series. For this reason I prefer to construct the coil 27 of a high resistance material such as iron, German silver, nichrome, etc., thereby introducing suificient resistance to prevent an unnecessary flow of current between the mains, but stillaccomplish the purpose of the device.

One of the objects of my invention is to provide a device which is controlled by temperature changes based upon the current flowing through the device and the time that such current flows, therefore, I find it necessary to provide means of preventing the thermostatic elements from contacting under other conditions than those intended and which combined current and time I will term a sustained current and may be made up of varying current and time values, i. e., the greater the current the less the time, I find that if only a single thermostatic element is used that this element is affected by changes in the surrounding temperature, or what might be termed the room temperature, such that if the thermostatic element should be set to operate under a given room temperature and a given current after flowing a length of time that this setting would varyshould the room temperature vary. For this reason I employ the two thermostatic elements 19 and 22 so related to each other that the space between the contacts 21 and 24 will remain substantially constant regardless of the changes in the room temperature, as this temperature would aflect both elements 19 and 22 alike and, therefore, the space between the contacts 21 and 24 would remain constant or practically so. With the construction shown, in which one the element 22.

element 19 is entire and the other element 22 is U-shaped, I find that for all practical purposes such construction maintains the separation of the contacts 21 and 24 practically constant providing the elements are of uniform thickness. If it is desired to secure more accurate conditions then the element 19 may be made U-shaped similar to the element 22.

One function of the thermo-responsive device T is to protect the translating device from a too great temperature rise, and as the device may be used with different classes of translating devices which will permit of different temperature raises, I provide means of varying the thermo characteristic of the thermo-responsive device, and I do this by mounting upon the thermo element 22 a rider 30 which is movable upon the element 22 and will increase or decrease the length of the element 22 through which the current can traverse thereby increasing or decreasing the length of the element 22 is subjected to the heating action of the current. With a given current the movement of the free end of: the element 22 will be greater or less, depending upon whether the rider 30 is closer to the free end or to the fixed end of Therefore, by means of the rider 30 I am able to adjust the thermo-responsive device so that it will operate when the temperature of the translating device X has reached a predetermined degree or close thereto.

The armature 6 can be made to operate under different conditions by varying the size or tension of the spring 7. I

In Fig. 8 I have shown a rotary switch S controlled by the operation of the armature 6, and this switch will control the opening and closing of the main line circuit leading to the contacts 8 and 9. In Fig. 8 the switch S is shown in its open position. When mydevice is combined with a switch S and a translating device X, as for instance, a motor, the coil 12 will be energized with a normal flow of current insufiicient to operate the armature 6 and also insufiicient to operate the armature 6 under normal starting conditions, but if while running the load on the motor X should be increased suddenly to an abnormal amount then the energization of the coil 12 would be suflicient to immediately attract the armature 6 and the switch S would be released to open the circuit from the source of supply.

Also, if the translating device X should be operated under a steady overload suflicient to endanger the same, but such overload current is not sufiicient tooperate the armature 6, then after such overload continues for a predetermined time, thereby heating the translating device up to a predetermined amount, then under such operation, when the been reached predetermined temperature has e thermo-responsive deupon the motor, t

which vice would operate, due to the sustained current, to close its circuit thereby connecting the free end of the coil 27 to the circuit 25, and this amounts to throwing the auxiliary coil 27 in series with the coil 12 and the two across the two sides of the circuit from the source of power, and current will flow therethrough, directly increasing the energization of the core 2 by the ampere turns of coil 27, and at the same time the current through the coil12 will be increased by the amount flowing through the coil 27 thereby further increasing the energization of the core 2, and which will be sufiicient to cause the armature 6 to be attracted thereby releasing the spring held switch S to open the circuits from the source of power.

From this it will be seen that I have a device for protecting the motor against a sudden overload of a predetermined amount, or to protect the motor at a lower overload after such overload has raised the temperature to a predetermined amount.

The switch may consist of a rotatable insulating disc 40 and which is held under spring tension when in its closed position and biased to open, as is usual with snap switches. The disc 40 is r'otatably mounted on the stem 41; as is also a lever of insulating material 42, which is free to rotate relative to the disc 40., The lever 42 is provided with a handle 43 by means of which the lever 42 is operated. The disc is also provided with four reciprocating contact members 44, 44, 45 and 45 connected together by the spring members 46 and 47 which are held to the disc 40 by the screws 48. These reciprocating contacts are adapted to engage with contacts 4949 and 50-50, which are secured in the base 1. The contact 49 is connected to the post 51 bythe conductor 52 and the contact 49' is connected to the post 8 by means of the conductor 53, while the contact 50 is connected to the post 54 by the conductor 55 and the contact 50' is connected to the post 9 by means of the conductor 56.

The armature 6 is provided with a catch 57 which engages with the stop 58 when the disc 40 is rotated to its closed position and holds the disc in such position thereby closing the circuits from 49 to 49' and from 50 to 50.

To close the switch the handle-43 is rotated in a clockwise direction which moves the lever 42 into engagement with the projecting contact 45 thereafter causing a rotation of the member 40, and this rotation is continued until the catch 57 engages with the catch 58. The lower end of the lever 42 will now be to the left of catch57.

If it is desired to open the switch by hand the lever 42 is rotated in an anti-clockwise direction through the medium of the handle 43, and the right-hand side of the lower end of the armature contact as shown at a the lever 42 being beveled will engage with the catch 57 thereby depressing the armature 6 and permitting the disc 40 to rotate to an open position.

As stated at the beginning of this specification, the armature can be employed to act as a switch in itself, if so desired, in order to operate or electrically control distant apparatus, and this can be brought about by securing a vcontact a to the base member of such construction, as is well known to those skilled inthe art, and which will engage with 6 if it is desired to operate with. a normally closed circuit or employ a if it is desired to operate on an open circuit. In either case, a conductor would be led from the armature 6 and from the contact a or a" to such device as is to be controlled by the mechanism shown in It will be noted that when the thermoresponsive element closes that the twocoils rurrent.

The coil 27 could be made in the form of a resistance R separate from the core 2, in which case it would not add to the turns of the core 2, but would still be in series with the coil 12 and this construction is perfectly feasible by properly proportioning the resistance of the said coil and the ampere turns of the coil 12 so that sufficient energization of the core 2 will be secured. o

By connecting the coil 27 as I have shown it permits a smaller number of turns in the two coils, therefore reducing the size of the device.

There are a number of modifications in my invention which will suggest themselves to those skilled in the art, therefore, I do not wish to be limited other than by my claims.

0 aim:

1. A circuit closing device comprising a pair of spaced thermo-responsive elements arranged to maintain a constant separation when the surrounding temperature changes, ry the temperature of oneelement independent of the other element to contact it with the other element to close the circuit and means to vary the thermal charactefl istic of one of termmed requiremen 2. A hermo-responsive device comprising a thermo-responsive element, the distortion of which is affected by the temperature of the surrounding air, auxiliary means to effeet the distortion of the element, means forming a part of the element to adjust the degree to which the auxiliary means affects the element and another thermo-responsive element affected in like each other and rigidly the elements to meet a predemanner as the first element by temperature changes of the surrounding air, but not affected by theauxil- 1ary means and adapted to make and'break' contact with the first thermo-responsive element under varying temperature conditions.

3. A thermo-responsive device comprising a pair of thermo-responsive elements adapted to bedistorted to make and break contact with each other said elements being constructed to respond alike to ambient temperature changes irrespective of the speed of such changes to maintain a constant relation with each other under changes in the temperature of the surrounding air'and means for heating one of said elements independently of the other to change the constant relation between the elements by affecting the amount of distortion of one element relative to the other.

4. A thermal current switch, comprising a pair of spaced bimetal strips insulated from mounted at one end of each strip, the opposite ends of the strips having cooperating contact points arranged to engage each other caused to approach, said strips being arranged to be similarly affected by changes in ambient temperature to maintain substantially constant spacing of said contacts in-' sofar as said strips are affected by the temperature of the surrounding atmosphere, one of said strips having a slot therein extending fromthe fixed end thereof toward the free end thereof, a rider mounted on said slotted strip and slidably movable along said strip to bridge said slot at adjustable positions along said strip, an electric circuit having said slotted strip arranged in series therein for supplying a current to said slotted strip to heat said strip independently of its cooperating strip, and a conductor connected to said cooperating strip and arranged to be electrically connected with said slotted strip when said contacts are brought into engage ment;

In testimony whereof I afix my signature.

HERBERT E. RUiPP when said ends are-

Images