US2439338A - Signal device for thermostatic switches - Google Patents

Description

April 6, 1948. H. B. Fue-E Er AL SIGNAL DEVICE FOR THERMOSTATIC SWITCHES Filed lay 3, 1944 Patented Apr. 6, 1948 SIGNAL DEVICE rIHERMOSTATIC SWITCHES Harry B. Fuge and James W. Blomberg, Somerville, N. J., assignors to The Singer Manufacturing Company, Elizabeth, N. J., a corporation oi New Jersey Application May 3, 1944, Serial No. 533,856

Claims. (Cl. 2200-121) This invention relates to signal devices and more particularly to a signal device for a thermostatically controlled switch.

Switches of this type are often used on electric motors to break the electrical circuit to the motor on a rise of current which would be injurious to the motor. These switches automatically break the circuit to the motor, but in order for the motor to be connected again to the electrical circuit the switch must be reset manually. One of the objects of this invention is to provide a signal associated with the switch for indicating that the circuit to the electric motor has been broken by the thermostatic switch and that the switch must be manually reset before the motor can again be started.

Another object of this invention is to provide a signal device for a thermostatic switch which is built into the push-button of the switch and which does not increase the overall dimensions of the switch. A still further object of this invention is to provide a combined signal device and thermostatic switch which'is economical in construction, easy to assemble and may be built as a unit and applied to the electrical device which it is adapted to protect.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings- Fig 1 is a vertical sectional view taken substantially through the center o f .a thermostatic switch having our signal device embodied therein.

Fig. 2 is a sectional view taken along the line 2--2 of Fig. l.

Fig. 3 is a top plan view of the device shown in Fig. 1 with the push-button removed.

Fig. 4 is a side elevation of the push-button showing the lamp encased therein.

Fig. 5 comprises perspective views of the push` 2 ing formed with U-shaped slots I4 which are adapted to receive screws for the purpose of removably securing the base in the aperture II of the motor casing I0.

The base I2 is provided with holes in which the contacts or terminal lugs I5, I6 and Il are placed. The lugs I5, I6 and I'l have their upper ends bent over to form fiat contact plates I5', IE and II and electrically connecting the contact plates I5 and I 6 is a resistance heater wire 38. A bimetallic disk I8 is disposed within the upstanding walls of the cup-shaped base I2 and is provided with two contacts I9 and 20 on its lower face. The disk I8 is held in position by means of a screw 2| which is threaded into the base member I2. When heated, the disk I8 has the characteristic of snapping from the convex position shown in full lines in Fig. 1 to the opposite convex position shown in dotted lines in Fig. 1. However, the disk is unable, upon cooling, to snap back to its original position and must be moved back manually. From the above it Will be understood that. when the disk is in the position shown in full lines in Fig, 1, the contacts I9 and 20 are in engagement with the bent over ends I5 and I'I of the terminals I5 and I'I and the electric circuit to the motor is closed through the disk I8, and when th'e disk is in its dotted line position the contacts I9 and 2U are out of engagement with the terminals I5 and II and, consequently, the electric circuit to the motor is open. The above described switch is old and well known and further detailed description is deemed unnecessary.

Located at one side of the bimetallic snap-act ing disk I8 and extending through' the reduced portion I I of the aperture II is a push-button 22 made of translucent material. The push-button 22 is dome shaped and and is formed with an enlarged laterally extending foot portion 23 which is provided with diametrically arranged narrow slots 24. Immediately below each of the slots 24 is a second slot 25 which is somewhat wider than the slot 24. Located within the push-button 22 is a glow lamp 26 provided with spaced electrodes 21 and leading in wires 28. The free ends of the wires 28 are soldered or otherwise electrically connected to the ends of the conductors 29 located within the push-button. The conductors 29 extend through the slots 24 in the base of the push-button and their ends are bent over as indicated at 30 so that they lie along the peripheral wall of the foot portion 23. The bent over ends of the conductors are in Contact with the resistors 3| which are embedded in the inner peripheral 'wall of the cup-shaped base member I2 and are in engagement with the terminals I and I1. Fitted into the lower portion of the foot portion 23 is a plate 32 made of insulating material and formed with diametrically opposed ears 33 which fit into the'slots 25 formed in the foot portion 23 of the push-button. 'Ihe plate 32 is provided on its lower face with three buttons 34 which are adapted to engage the disk I8 and force it from the dotted line position to the full line position to close the circuit to the motor when the push-button 22 is depressed, From the above it will be understood that the push-button and light may be built as a unit and applied to the thermostatic switch. l

In order to guide the push-button 22 and prevent it from turning relative to the base I2, the outer periphery of the foot portion of the button is provided with two closely spaced lugs 35which are located on opposite sides of a rib 36 which projects from the inner wall of the cup-shaped base member I 2. This arrangement prevents the push-button from turning relative to the base and thus maintains the bent over ends 30 of the conductors 29 in contact with the resistors 3|. In order to maintain the push-button 22 centrally of the upstanding walls of the base "I2 the foot portion of the push-button is provided with a lug 31 located diametrically opposite the lugs 35. From the above it will be understood that the bent over ends 30 of the conductors 29 and the lugs 35 and 31 maintain the push-button 22 in spaced relation with the upstanding wall of the cup-shaped base I2.`

In one use of our improved combined signal device and thermostatic switch, the switch is applied to an electric motor and if the rotor of the motor should stall, or if the motor should be abnormally overloaded, the combined heat from the motor, the resistance Wire 38 and the heat generated by the resistance oi.' the thermostatic disk I8 causes the disk I 8 to snap from the full line position shown in Fig. 1 to the dotted line position. It will be observed that the glow'la'mp 26 is at all times electrically connected to the terminals I5 and I1 through the resistors 3| and electrical conductors 29. However, when the disk I8 is in full line position the terminals I5 and I1 are electrically connected through the disk I8 and as the disk offers considerably less resistance to the passage of the current than the resistors 3i the lamp does not glow. When the disk I8 snaps to the dotted line position the terminals I5 and I1 are no longer electrically connected` by the disk and suicient current will pass through the resistors 3| to cause the lamp 26 to glow and thereby indicate that the thermostatic switch has opened and must be closed before the motor can be started. After the disk has snapped to its open circuit or dotted line position, the push-button 22 may be pushed towards the base I2 so that the button 34 on the plate 33 will engage the upper face of the disk I 8 and iiex the disk so that it will return to closed circuit position.

From the above it will be observed that the signal for the thermostatic switch has been placed within the push-button and that the overall dimensions of the switch have not been increased. It is apparent that the above described construction has a wide variety of uses, and it will be'understood that the form, and arrangement of the several elements employed may be eficaces] i y. as may be fairly embodied within'b the spirit and scope of the appended claims.

Having thus set forth the nature of the invention, what we claim herein is:

-1. In a `thermostatic device having a basemember carrying spaced terminals anda heat responsive snap acting bimetallic disk bridging the space between the terminals and having an initial circuit closing position and an open circuit position to which it moves by thermal action, the improvement which comprises the provision of a push-button located on one side of said disk for moving said disky from open circuit to closed circuit position, resistance elements embedded in said base member and in electrical contact with said terminals, conductors carried by said push-button and slidably engaging said resistance elements, and a glow lamp disposed within said button and electrically connected to said conductors.

2. In a thermostatic device having a basemember carrying spaced terminals and a heat responsive snap acting bimetallic disk bridging the space between the terminals and having an initial circuit closing position and an open circuit position to which it moves by thermal action, the improvement which comprises the provisions of a push-button made of translucent material and located on one side of said disk for moving said disk from open-circuit to closed circuit position, two oppositely disposed resistance elements in electrical contact with said terminals, conductors carried by and movable with said pushbutton, said conductors having a sliding engagement with s'aid resistance elements, and a signal lamp disposed within said push-button and electrically connected to said conductors.

,3. In a thermostatic electric switch comprising a base-member carryingspaced stationary electrical contacts, a heat responsive snap-acting disk located on one side of said contacts and adapted to engage said contacts in normal circuit closing position and to move away from said contacts to an open circuit position upon an abnormal rise in temperature, the improvement which comprises the provision of a pair of spaced resistors electrically connected to said contacts,

a push-button located on the side of said disk opposite to the contacts, conductors carried by said push botton and contacting said resistors,

' and a signal light carried by said push button contacts to an open circuitrposition upon an abnormal rise in temperature, the improvement which comprises the provision of a pair of -spaced resistors electrically connected to said contacts. a translucent hollow push-button located on the side of said disk opposite to the contacts, v said push-button being confined to a right line movement, electrical conductors passing through the Walls of said push-button and having their extending ends in engagement with said resistors, and a glow -lamp located within the hollow pushbutton and electrically connected to said conductors.

5. In a thermostatic electric switch comprising a base-member carrying spaced stationaryelectrical contacts, a heat-responsive snap-acting disk located on one side of said contacts and adapted to engage said contacts in normal circuit-closing position and to move away from said contacts to an open circuit position upon an abnormal rise in temperature, the improvement which comprises the provision of a pair of spaced resistors electrically connected to said contacts, a hollow push-button located on the side of said disk opposite to the contacts, said push-button being conned to a right line movement, electrical conductors passing through the walls of said push-button and having their free ends in engagement with said resistors, and a glow-lamp located within the hollow push-button and electrically connected to said conductors.

HARRY B. FUGE.

JAMES W. MOMBERG.

6 REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 506,729 y Rex Oct. 17, 1893 1,184,234 Goehrend May 23, 1916 1,985,276 Brach Dec. 25, 1934 2,199,388 Bolesky May 7, 1940 2,234,954 Bergman Mar. 18, 1941 2,246,613 Bigman June 24, 1941 2,276,785 La Mar Mar. 17, 1942 2,293,179 Swingle Aug. 18, 1942

Images