US1893827A - Electric switch - Google Patents

Description

Jan. 10, 1933.

B. E. GETCHELL 1,893,827

ELECTRIC SWITCH Filed Jan. 15.- 1950 6 Sheets-Sheet 1 INVENTOR B e '01): E. Chel],

AT ORN CHELL.

ELECTRIC SWITCH Jan 10, 1933.

Filed Jan. 15. 1950 6 Sheets-Sheet. 2

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ATTORNEY Jan. 10, 1933. B. E. GETCHELL. 9

' ELECTRIC SWITCH Filed Jan. 15. 1930 6 Sheets-Sheet 4 Jan. 10, 1933. GETCHELL 1,893,827

ELECTRIC SWITCH Filed Jan. 15. 1930 6 Sheets-$heet 5 B. E. GETCHELL ELECTRIC SWITCH Jan. 10, 1933.

Filed Jan. 15. 1930 6 Sheets-Sheet 6 ATTORNEY Patented Jan. ,10, 1933 UNITED STATES PATENT OFFICE BENJAMIN E. GETCHELL, F PLAINVILLE, CONNECTICUT, ASSIGNOR TO THE TRUE- BULL ELECTRIC MANUFACTURING COMPANY, OF PLAINVILLE, CONNECTICUT, A

CORPORATION OF CONNECTICUT ELECTRIC SWITCH Application filed January 15, 1930. Serial No. 420,929.

My invention relates particularly to the class of electric switches commonly known as the remote control type, such switches being usually provided with electro-magnetic and push button means for starting and stopping a motor.

It has been customary in former constructions to utilize an electro-magnet to close the switch circuit and, in some instances, to further utilize the magnet as a low-voltage release means but, in those constructions which are alsotprovided with an overload releasing means, it has been customary to provide a separate thermostatic relay means of one form or another and the result has been a complicated construction built up of many parts and requiring considerable special wiring both at the factory and in the installations of the device.

These constructions have been diflicult for even a trained wireman to understand and diflicult to wire even after the purpose of all the detail parts and flexible leads had been explained to him. It is my principal object to eliminate those objections and to provide a remote control switch having automatic lowvoltage and overload means, together with a magnet and push button means and having all of the co-related parts mounted and assembled as a separately detachable unit with the complete elimination of flexible leads and, further, with the parts and terminals so arranged that a wireman will have no difliculty in understanding the device at a glance, and

' no difficulty in tracing the circuits or in wiring up the switch.

Another object is to provide a construction including an electromagnet for operating the movable contacts to close the circuit and to maintain the contacts in closed position while the voltage of the circuit remains normal but to release the contacts when the voltage fails or drops to a pre-determined point.

Another object is to provide a switch having normally inactive thermostatic means for opening the circuit through the magnet and thus cause the opening movement of the switch in the event of a pre-determined overload in the circuit. I

units in the circuit to be controlled and adj acent to the thermostatic members.

Another object is to provide an automatic switch construction having a bi-metallic element and a separate heater element for the bimetallic element, the heater element being in series with the circuit to be controlled and the bi-metallic element being independent of the circuit and affected solely by the heat from the heater element.

Another object is to provide a multi-polar switch construction having an automatically operating thermostatic switch releasing means in two or more of the poles of the circuit and co-acting means whereby the operation of any one of the switch releasing means will automatically and simultaneously operate all of the co-acting switch releasing means and thus open all poles of the circuit.

Another object is to provide a multi-polar switch having automatic thermostatic circuit opening means in each of a number of poles of the circuit and .a transverse cross-bar member by means of which all of the circuit opening means may simultaneously be re-set into normally inactive position by means of a single externally accessible push button which button may also be used for the normal operation of the switch.

Another object is to provide a remote control switch having terminals and connections so arranged that it may be wired for either local control or for remote control or for both local and remote control without changing any of the parts after the switch leaves the factory and without the addition of any connectors or other parts.

Another object is to provide an automatic switch construction including thermostatic switch releasing means and separate heater elements for the thermostatic means, the heater elements being of pre-rated capacity and being attachable or removable from the front of the base without disturbing the thermostatic member or any other parts of the construction.

Another object is to provide an enclosed remote control switch construction in which the stationary and movable contacts may be removed or replaced from the front of the base without removing the base from the enclosing box and without disturbing any of the other parts.

Another object is to provide a remote control switch having the aforementioned desirable automatic features but which is reduced in size to arelatively very small and compact construction and yet ,is amply sturdy and unusually efficient in performance.

Another object is to provide an enclosed remote control switch having thermostatic and electro-magnetic means for operating the switch within the box and having external push buttons for operating the switch under normal circuit conditions and for re-setting the switch after its automatic operation.

Fig. 1 is a front view showing the switch in its box with the cover and part broken away.

Fig. 2 is a perspective view of the box closed.

Fig. 3 is a horizontal sectional view take on the plane of the line 3-3 of Fig. 10 the i switch being inverted.

Fig. 4 is a perspective. view of parts of the thermostatic latch.

Fig. 5 is a vertical sectional view on the general plane of the line 55', Fig. 1, showing the switch open.

Fig. 6 is a side view of the righthand side.

Fig. 7 is an end view.

Fig. 8 is a perspective view of one of the thermostatic elements.

Fig. 9 isa perspective view of one form of heater unit.

Fig. 10 is a rear view of the switch.

Fig. 11 is a vertical section on the plane of the line 11-11 of Fig. 1.

Figs. 12 are detail perspective views of the front and back of one of the movable contacts.

Fig. 13 is a side view of the local push button unit.

Fig. 14 is a rear View of the same, showing the shanks of the buttons in section.

1 Fig. 15 is a diagrammatic view showing the local control contacts in running position.

Fig. 16 is a diagrammatic View showing local contacts in the position they occupy when tripped by the action of an overload.

Fig. 17 is a diagrammatic view of the enrepresent the switch arranged for local control.

Fig. 18 is a diagrammatic view showing the circuits arranged for remote control.

The box or receptacle which will usually be employed to house the mechanism consists of a body 15 with a cover 16 hinged at 17 and provided with some suitable form of catch-locking device or sealing device such as 18.

The cover of the box is provided with openings through which the push buttons 19 and 20 are accessible when the cover is closed. Preferably the box cover is recessed at 21 so that the buttons do not project beyond the outer surface of the cover.

The switch mechanism proper preferably includes a back plate 22 on which the various parts of the mechanism are assembled or supported and this back plate itself constitutes a part of the means of connection of the switch with the box.

An insulating body 23 afiords immediate support for the conducting parts of the switch and is itself supported from the back plate 22'by means of side plates or brackets 24 and 25.

The switch as shown is intended for a threewire system. There are three upper line terminals 26, 27, and 28 and corresponding lower load terminals 29, 30 and 31 with switch members, thermostatic devices, electro-magnetically controlled switch closing and holding means, and push buttons for normally starting, stopping and resetting the switching means.

Each of the three circuits has a main switch with stationary terminals such as 32 and 33 and a movable switch member 34. All of the movable switch members are carried by a cross bar 35, which is connected as hereinafter set forth with an electro-magnetically actuated device.

Details of the main switch member and its correlated contacts are claimed in my Patent 1,796,449, dated March 17, 1931.

Each of the outer poles of the three pole switch is provided with a heater unit having terminals 36 and 37 a part of which serves as a heater resistance element. The body 23 is provided with a passage 40 in which the heater element is located adjacent to the thermostatic member 41. The latter is carried by the supporting bracket 42 secured to the rear of the body and the heater unit is mounted at the opposite side or front of the body.

The electro-magnet has a coil 43 and a core 44 for supporting it. This core is mounted in a channel-like frame 45 which is secured to the bracket plate 22. The terminals of the coil are secured respectively to the line terminals 26 and the rear terminals 46 and the latter in turn is connected to spring contact arm 47. The core 44 is loosely pivoted at 48 in the frame 45 and has a limited permissive movement between the back of the channel 45 and the lugs 49. The armature 50 is loosely pivoted at 51 in the channellike carrier which in turn is pivotally supported at 53 in the frame which carries the magnet core and coil.

The cross bar 35 which carries the movable switch member has extensions 54 somewhat loosely guided in inclined slots 55 in the side plates 24 and 25 respectively. The bell crank lever 56 has its opposite ends 57 pivoted in the side plates and lugs 58 parallel to the pivots loosely engaged in the ends of links 59 which are in turn somewhat loosely connected with the extensions 54 in the iniulating carrier for the movable switch memers.

The link 60 has its rear end connec ed to the projecting lug 61 and its front end is provided with a slot 62 for the pin 63 in the upper end of the armature carrier. Fingers 64 serve to laterally position the link 60 on the pin 63.

When the magnet is fully energized the armature 50 is attracted and the link 60 thrust rearwardly so as to tilt the lever 56 about its pivots 57 and thus through the medium of the link 59 draw the movable switch carrier 35 with the switch members 34 to closed circuit position and compress the springs 65. When the magnet is de-energized the armature is released and falls away by gravity and its weight tends to pull the link 60 and the bell crank lever 56 outwardly and downwardly. The weight of the movable switch members and their carrier, as well as the weight of the link 59 also tends to move the switch members to open circuit position. The lost-motion connection of the pin 63 and the slot 62 allows the armature to have a certain freedom of movement so that when it starts to move it is substantially free of the link 60 and attached parts and thus able to obtain considerable momentum without the assistance of the other parts.

In this way a hammer-like blow is given which prevents the parts from sticking. The loose pivoting of the armature 50 in its frame 52'permits it to adjust itself to the core of the magnet and thus adapt itself to irregularities in mechanical construction.

By loosely pivoting the core 44 so that it tends to hang forward against the lugs 49 ll provide a yielding action so as to avoid shock to the magnet or other parts when the armature is attracted to the circuit closing pos tion.

On the back of the insulating body are mounted circuit terminals 70, 71. 72 and 46. For the purpose of local control line terminal 27 is d rectly connected with the'rear terminals 71 by conductor 73 and the latter is connected to a spring arm 7 4 which is set in a groove in the rear of the body. Another spring arm contact 75 has its upper end connected to terminal 72 and its lower end interposed between the contact arms 47 and 74.

haft 76 is pivotally supported in the side temperature it will turn the shaft against the tension of the spring 77. That is to say, the warping of the thermostatic arms tends to rotate the shaft 76 clockwise as viewed in Fig. 11 and against the pressure of the spring 77 A latch 80 is pivotally supported by a frame 81 and under tension of a spring 82. This frame is anchored to the insulating body by means of a screw 83, which also serves to secure in place an insulating block 84 which supports the push buttons 19 and 20.

A conducting plate 85 is mounted between the body 23 and the block 84. The lower end of the plate 85 is a part of lower load terminal 30 and the upper end of the part is secured. to the contact 86 of the central switch unit the upper contact of which is 87 and movable switch member 88 in the neutral circuit.

The block shaft 76 has an arm with a head 89 which is adapted to interlock with a T- shaped slot 90 in the latch 80.

The shanks of the push buttons 19 and 26 are flattened as shown at91 so that they can slide in and are non-rotatably guided by the narrower parts of slots 92 in the plate 85. The springs 93 tend to press the buttons outwardly. The inner end of the upper push button 19 is adapted to engage the lower end of the contact arm 74 so as to press it to the rear and cause it to contact with the lower end of arm 75 for closing the switch to start the motor with which it is connected.

The lower push button 20 has its rear end in line with the lower end of the latch 80 so as to re-set the catch when it has been tripped by the action of the thermostat. A loose pin 94 is mounted in the body behind the spring contact arm 74 so that when the contact carrier'35 is moved rearwardly it engages this pIn and forces the rear end of the contact arm 74 against the contact 75. When the thermostat acts under overload its projection 79 operates on the arm 78 to rock the shaft 76 and thus release the latch 80 which immediately tilts so as to move the lower end of the contact arm 47 away from contact arm 75.

To reset the switch after its automatic operation. the lower button 20 is pushed in and the latch 80 reset so that the spring contact arm 47 is again allowed to engage the contact arm bridged across the respective upper and lower contacts 32 and 33 and the pin 94 in back of carrier 35 pressing against contact spring 74. The shunt magnet coil circuit is then from line terminal 26 through the coil 43 to terminal 46, spring arm contact 47, center contact arm 75, contact arm 74 to terminal 71 and thence to line terminal 27.

To break the circuit and stop the motor the button is.-.- pressed inwardly. This tilts rocker 80, separates contacts 74 and 75, opens the magnet coil circuit, deenergizes the magnet, releases the armature 50 and carrier and allows the springs 74 and 65 and gravity to throw the carrier and switch members 34, 88, etc., outwardly and open all three poles or branches of the circut.

The switch is' automatically opened in a similar manner in the event of an overload;

the excessive heat of one or both of the resistance members causes one or both of the bimetallic thermostatic members 41-41 to warp and to rotate the shaft 76 b means of screw 79 which action rotates hea 89 and releases the latch member 80 and allows the spring 82 (Fig. 4) to tilt the rocker latch 80 which in turn separates contact 47 from 75 thus opening the circuit through the magnet and allowing the switch to open.

In case the voltage of the circuit falls below a predetermined point, the magnet will not be able to hold the armature and the carrier will accordingly be released and drop down and release the pin 94 and thus open the coil circuit as Well as the three main branches.

In case the switch has opened automatically on an overload the rocker. and latch may be reset by pressing the button 20 inwardly. This tilts the rocker 80 till it engages the latch 89 and allows contact 47 to engage contact 75. The switch can then be closed by simply pressing on the button 19 so as to contact springs 74 and 75. This closes the magnet shunt circuit, energizes the magnet coil, attracts its armature and moves the carrier 35 to closed circuit position and presses pin 94 against spring arm contact 74 so that the coil circuit remains complete when the button 19 is released.

2. 'vand w are normally connected by member 3 so that the switch terminals and 71 are electrically connected. Separation of contacts '0, 3 and w will open the circuit through the magnet switch and stop, the motor, etc. Connection of 'w and a: by 2 connects the line terminal 27 through 70 to w, z, m to 72, 7 5, 47, 46, coil and line 26 closes the main switch and starts the motor.

The electro-mganetic device per se is claimed in my. application 643,317, filed November 19, 1932.

I claim:

1. A three pole switch having three line terminals, three load terminals, a switch member interposed between each line terminal and its corresponding terminal, a heater member interposed in circuit with each one of two poles of the switch, a magnet coil having one terminal connected to one of the line terminals, a spring contact arm connected to the other magnet terminal, a spring contact arm connected to another of said line terminals, a contact mounted between said contact arms, a rocker member having one end interposed between said con tact arms for moving the same, a springpressed latch member adapted to hold said rocker member in position, thermostatic members actuated by said heater members and adapted to release said latch member, two push buttons, one of said buttons being located in position to move said contact arms into electrical connection' for closing the magnet coil circuit and the other push button being arranged to move said'rocker member for opening the magnet coil circuit and for.

re-setting the latch member, said rocker member, when released, being adapted to electrically disconnect said spring contact arms, an armature actuated by said electromagnet for moving all of the movable switch members to closed circuit position, and means actuated by the movement of said switch members to closed circuit position for holding said switch contact arms in electrical connection, one of said spring contact arms being biased to disrupt the electrical connection automatically when said switch members move to open circuit position.

2. An electric switch including appurtenant movable and stationary main contacts and three auxiliary switch contact arms cooperating therewith, one of said auiriliary contact arms being interposed between the other two, a spring-pressed rocker member movable between the ends of two of the auxiliary contact arms, a spring-pressed latch to automatically disconnect said auxiliary contact arms when released by the operation of said thermostatic member.

3. An electric switch including appurtenant movable and sationary contacts, two auxiliary switch contacts and an intervening auxiliary contact, a rocker member having one end interposed between two of said auxiliary contacts, a spring-pressed push button for moving one of said auxiliary contacts into electrical connection with said interposed contact, a movable switch member, eleetro-magnetic means for actuating said movable switch member, means actuated by the closing of the circuit through said switch member to hold the auxiliary contacts in electrical connection with each other and a spring-pressed push button for actuating said rocker member to electrically separate one of said auxiliary contacts from the said interposed contact.

4. An electric switch construction including three single pole circuits, each circuit having a line terminal and a load terminal, a thermostatic heater connected in each of two of said circuits, a movable switch member for each of said circuits, an electro-magnetic coil and armature adapted to move said switch members to closed circuit position, an auxiliary switch comprising three contact members two of which are movable and the other interposed between the movable members, circuit terminals for each of said contact members, said magnet coil having one terminal connected to one of the terminals of said auxiliary switch and the other terminal connected to one of the line terminals, another one of said line terminals being adapted to be alternatively connected to one of the other terminals ofthe auxiliary switch, one of the terminals of the interposed contact member being adapted to be connected to a remote control switch and one of the terminals of one of the movable contact members being also adapted to be connected by the remote control switch when disconnected by the local load terminals.

5. In an electric switch a pair of termostatic heaters, a bendable thermostatic membcr associated with each of said heaters, a rock shaft adapted to be moved in one direction by said thermostatic members, a switch for moving said shaft in the opposite direction, a rocker member having a latch connection with said rock shaft, a spring for moving said rocker member in one direction and a push button for moving said rocker member in the opposite direction.

6. in an electricswitch a plurality of main switch members, an electro-magnetic device foractuating said main switch members, an auxiliary switch, a connector between the auxiliary switch and the main switch memher for automatically closing the auxiliary switch by the movement of themain switch,

a spring-pressed push button for closing the auxiliary switch independently of the main switch, a spring-pressed push button and means actuated thereby for opening the auxiliary switch independently of the main switch, a thermostatic member and means actuated thereby for opening the auxiliary switch independently of the main switch,

7. In an electric switch, a supporting framework, stationary contacts, a movable switch member, a carrier therefor, a lever piving opposite ends of said carrier with said lever, switch actuating mechanism including an electro-magnet, an armature for said magnet connected to said lever for actuating said carrier, and latch mechanism coacting with said actuating means and including a shaft pivotally supported by said frame, a spring tending to rotate said shaft in one direction, a thermostatic member adapted to rotate said shaft in the opposite direction and a latch coacting with said shaft and adapted to be released by the operation of said thermostatic member.

8. A switch of the character described having at least two line terminals, each line terminal and a load terminal being arranged in a branch circuit and two load terminals, a switch member interposed between each line terminal and its corresponding load terminal, a heater member interposed in one branch circuit of the switch, a magnet coil having one terminal connected to one of the line terminals, an auxiliary switch having a contact arm connected to the other magnet terminal, a contact arm connected to another of said line terminals and a contact mounted between said contact arms, a rocker member having one end interposed between said contact arms for moving the same, a spring-pressed latch member adapted to hold said rocker member in one position, a thermostatic member actuated by said heater member and adapted to release said latch member, two push buttons, one of said buttons being located in position to bring said contact arms into electrical connection for closing the auxiliary circuit and the other push button being arranged to move said rocker member for opening the auxiliary circuit and for re-setting the latch member, said rocker member, when released, being adapted to electrically disconnect said contact arms, an armature actuated by said electro-magnet for moving all of the movable switch members to closed circuit position, and means actuated by the movement of said switch members to closed circuit position for holding said switch contact arms in electrical connection.

9. An electric switch construction including three single pole circuits each circuit having a. line terminal and a load terminal, a thermostatic heater connected in one of said circuits, a movable switch member for each ,otally supported in said frame, links connectof said circuits mounted to move simultaneously, an electro-magnet coil and armature adapted to move said switch members to closed circuit position, an auxiliary switch comprising three contact members at least two of which are movable and the other interposed between the movable members, circuit terminals for each of said contact members, said magnet coil having one terminal connected to one of the terminals of said auxiliary switch and the other terminal connected to one of the line terminals, another one of said line terminals being adapted to be connected to one of the other terminals'of the auxiliary switch, the terminal of the interposed contact member being adapted to be connected to a remote control switch and the terminal of one of the movable contact members being also adapted to be connected by the remote control switch and means Whereby the closing of the movable switch member closes the circuit through the auxiliary switch.

10. In an electric switch a thermostatic heater, a bendable thermostatic member associated with said heater, a rock shaft adapted to be moved in one direction by said thermostatic member, a spring for moving said shaft in the opposite direction, a rocker A member having a latch connection with said rock shaft, a spring for moving said rocker member in one direction, a push button for actuating said rocker member in the opposite direction, an auxiliary switch actuated by said rocker at one time and a push button for actuating said auxiliary switch.

11. In an electric switch a main switch member, an electro-magnetic device for actuating said main switch member, an auxiliary switch, means for automatically actuating the auxiliary switch by the closing of the main switch, a push button for closing the auxiliary switch independently of the main switch, a second push button and means actuated thereby for opening the auxiliary switch independently of the main switch, and means for opening the auxiliary switch independently of the main switch upon an overload.

12. In a switch, an electro-magnetically actuated main switch member, an auxiliary switch, a connector between the main switch member and the auxiliary switch whereby the auxiliary switch is actuated by the main switch member, a spring pressed rocker for partially actuating said auxiliary switch, means actuated by an overload for releasing said rocker, a push button for partially actuating said auxiliary switch to close the normal running circuit and a second push button for resetting the rocker and for moving the rocker to open the circuit through the auxiliary switch member.

BENJAMIN E. GETGHELL.

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