US1792311A - Electrical switch - Google Patents

Description

Feb. 10, 1931. H. K. KRANTZ ELECTRICAL SWITCH 8. 1922 4 Sheets-Sheet 1 Original Filed Aug.

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INVENTOR Huber) h. hmn fz WITNESSES:

Feb. 10, 1931. H. K. KRAN'TZ ELECTRICAL SWITCH' Original Filed Aug. 8. 1922 4 Sheets-Sheet INVENTOR Huberf/f fframz B a L L 7 ATTORNEY WITNESSES:

Feb. 10, 1931. K KRANTZ 1,792,311

ELECTRICAL SWITCH- Original Filed Aug. 8. 1922 4 Shaets-Shet 3 Fig. 4.

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23 as 34 as m WITNESSES: Q INVENTOR Huber! if. hramz Y fi AT'ToRNEY Feb. 10, 1931. H. K. KRANTZ 1,792,311

ELECTRICAL SWITCH Original F-iled Aug. 8, 1922 4 Shets-Sheet 4 56 INVENTOR WITNESSES: 5/

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" 7 ATTORNEY Huberf K. Kmnf overload on the circuit.

Patented Feb. 10, 1931 UNITED STATES PATENT OFFICE KUBERT K. KRANTZ, ROCKVILLE CENTER, NEW' YCRK, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA ELECTRICAL SWITCH Original application filed. August 8, 1922, Serial No. 580,409. Divided and this application filed May 18, 1926. Serial No. 109,822.

My invention relates to electric switches and particularly to those of the type wherein more than one switching operation is employed for starting motors.

My invention is particularly applicable for use in connection with small motors, such as are employed for driving household appliances and it has for one of its objects the provision of a compact structure embodying switches for controlling the circuits through the starting and running windings of a motor, together with means for automatically interrupting the circuit through the motor in case a short circuit or an overload occurseither during the starting of the motor or when such motor is operating under running conditions.

Another object of my invention is the I provision of means whereby the switch that controls the circuit through the starting winding will be automatically moved to open position after sufiicient time has elapsed to enable the motor to attain its normal running speed. I

2 Another object of my invention is the provision of a simplified form of operating mechanism whereby but a single handle is necessary in order to manually effect the operation of both switches.

A further object of my invention is the provision of means whereby the position of the operating handle when at rest indicates the position occupied by the running switch. Another object of my invention is the provision of an improved form of trip-free mechanism whereby the switch may be antomatically disengaged from the closing mechanism, when the switch reaches 115 closed position in order to insure that the switch will not be held closed against an Still another object of my invention is to simplify and improve generally the conslruction and operation of circuit controlling devices of the character above referred to.

As shown in the accompanying drawings,

Figure 1 is a plan view of a switch embodying my invention, the cover and the handle F ig. 6.) The bracket 31 is of U-shape and is being removed,

Fig. 2 is a view, partially in side elevation and partially in section, of the switch,

Fig. 3 is a detail view of the stationary contact members,

Fig. 4 is'a plan view of the cover plate,

Figs. 5 and 6 are side elevational and plan views, respectively, of the handle bracket,

Figs. 7 and 8 are plan and side elevational views, respectively, of the bracket which carries the movable contact members of the running switch,

Figs. 9 and 10 are plan and side elevational views, respectively, of the bracket which carries the movable contact members of the starting switch,

Figs. 11 and 12 are plan and side elevational views, respectively, of the lever for locking the running switch,

Figs. 13 and 14 are detail views of the upper and lower bearings respectively for the movable contact bracket members,

Fig. 15 isa detail View of one of the pins employed for effecting a connection between the handle bracket and the moving parts of the switch,

Fig. 16 is a plan view showing the positions occupied by certain of the moving parts at one stage of their operation,

Fig. 17,i-s a diagrammatic view showing the relation of the switches with respect to the circuits that are controlled thereby, and

' bers 26 and 27, the stop members consisting of bent-up portions of the frame 20. A rear bearing 28 is secured to the base 19 by upsetting the lower end at 29 (Fig. 2). The lower end of the shaft 24 is flattened slightly so that the handle bracket 31 may be non-rotatably engaged thereby, by reason-of the contour of a hole 32 in the bracket. (See I 45 the operation, .the running, and starting.

provided with a slot 33 at its middle portion within which a pin 34 mayslide horizontally. .The pin 34 is .providedwith grooves 36 (Fig. 15) that are engaged by the ends of a pair of tension springs 37. The other ends of the springs 37 are supported by a pin 38, the upper and lower ends of which lie in the cut-out portions 39 (Fig. 9) of a carrier 41 for movable contact members 42 (only one" of which is shown in Fig. 1) that co-operate with stationary contact members 43 to close the circuit through a starting winding of a motor connected in the circuit. 1 y 4 When the handle is turned in a counterclockwise direction, the pin 34, by reason of its locationin the slot 33 of the handlebracket 31 will also be moved in a counterclosure of i the grooves 36 of; the pin 34, and at its other end is supported. by a pin 51 whose ends lie in. recesses 52 of another movable contact bracket 53 (Figs. 1,7 and 8) that serves as I a support for movable cont-act members 54 that are moved into and out of engagement with stationary contact members 56 to eiiect a closure of what 'is herein designated as the running switch.

When the starting switch bracket 41 and the pin .38 that .is supported thereby are turned in a. counter clockwise direction, the

spring 49, which is' under tension, is'carried across theaxis of the rotatable members,

. thereby changing the direction of tension exerted by such spring 49 upon the bracket 53' and causing such bracket to-be moved to'the' position shown in Fig.16. Atthis stage of switches are both closed.

rections, respectively,

'.-- radiallyout 3 of engagement with the shouldered portion 44 of the-bracket 41, thus disen= gaging such bracket and permitting it to, move independently; of thehandle 25 and thehandle bracket 31;

Arelatively-stifl spring 58 has one of its ends secured at the point 59 totheframe- 2.0 and thefother 'end thereof secured at 61v to .the bracket 41" .(see Fig.1, 4 and9) As the" handle is'turn'ed to close the starting switch 6 the movement of, the bracket 41 increases the tension of the spring; 58 Upon the pin, 3 4' being tripped free ofthe shoulder44osfthe 7 V w 68 varies,-

As the contactcarrying brackets 53 and 411 move in clockwise and counter-clockwise di-f shouldered portions57 of the bracket 53 engage the front and rear; ends, respectively, of the pin 34, moving it.

ment.

bracket 41, as above described, the tension 7 of the spring 58 is sufiicient to return vthe bracket 41 to the position shown in Fi 1, against the tension of the springs 37 an 49.- This movement also returns that portion of the spring 49 which is supported by the pin 38 to the position illustrated in Fig. 1.

A locking lever 62 is pivotally supported in the frame 20, by a pin 60, and is normally biased in a clockwise direction by the spring 63 (Figs. 1 and 2). A pin 64 extends through openings 65 in the lever 62 and carries rollers 66 at its front and rear ends. When the bracket 53 has been moved to the position shown in Fig. 16, the roller 66, by reason of the clockwise tension exerted upon the lever 62 will engage a pair of shoulders 67. on the bracket 53 to hold the bracket 53 in closed position (as shown in Fig. 16) against the tension of the spring 49, when the end of that spring which is supported by the pin- 38 has been returned to the positionshown in Fig. 1,asabove explained.

The return movement of the bracket 41, under the tension 'of the spring 58, laces the handlebracket 31 under tension, y reason of the elongation-of the springs 37 but the bracket 31*is' prevented from moving to 01f position so long. as the pin 34 remains in engagement with the shouldered portion 57 of the "bracket 53. The position occupied by the handle 25, with respect to the stop lugs that -the running 26, and. 27, thus indicates switch is closed.

An electromagnet-68 for controlling the starting switch comprises two coils 69 and 7 0,

that may contain unequal ampere turns, and which are connected 1n the circult, as shown in F ig. 17, to co-operate with an armature which is carried upon a tail piece 72 of the starting switch bracket 41.- The difl'erential' in the magnetic forcesof the coils excited on the .armature71 is suflicient to hold the start ing switch closed when the switches are in the position occupied in Fig. 16. 5

The effective holding force of the magnet as will. be-hereinafter explained,

but normally holds the starting switch closed against the tension of the spring. 58 for a short period. When the magnetism has been sufiiciently reduced, as will be hereinafter. explained,the tension ofthe spring" 58 will impart an opening movement to the starting switch, as described above. I W1th the starting switch in the position conditions and maybe stopped either by manually effecting. an 'opemn'g movement of the running. switch motor will oper- 7 or* by automatically effecting such move;

Therunniiig switch may be opened'manually by turning the handle 25 in a clockwise direction, thus bringing the beveled portio jggj sqf.

12o" illustrated in Fig. 1, and the running switch w as illustratedin'Fig. 16, the

am under; normal running 73 (Figs. 5 and 6) of the handle bracket,

31 into engagement with the rollers 66 to cam them out of engagement with the shouldered portions 67 of the bracket 53. The handle is then held in its 0E position against the stop 26, by the tension of the springs 37, and the running switch bracket 53 is snapped to its open position by the tension of the spring 49.

The running switch may be opened automatically upon the occurrence of an overload by the coil 70 that actuates an armature 74 which is pivotally supported upon the pin and is biased outwardly by a spring 6301. An abnormal energization of the coil will attract the armature 74 causes the release of the p n 34 from its engagement with the shoulders 57.and allows the handle 25 to be returned to its oil position, as in the case of the manual operation above described.-

As shown more clearly. in Fig. 4, the frame 20 is provided with stop portions 76 for engaging the front ends of the pins 38 and 51 to limit their movements, the rear ends of the pins engaging the end'wallsof arcuate slots 76a in the base 19. The bearings 23 and 28 and the handle shaft 24 are of short length to permit movement of the spring 49 across the axis of the movable parts that are supported thereby, and the bracket members 31, 41 and 53 are of U-shape, to leave a clear space for movement by the springs 37 and 49. Furthermore, this U-shape construction of the bracket members 41 and 53, together with their recesses, which radiate from their central portions (see Figs. 7 and 9) permit the ready assembly or disassembly of these parts, in that such brackets may be inserted into place from the side of the switch by moving them radially into engagement with the grooved portion of the bearing members 23 and 28. The tension exerted by the spring 49, through the pins 38 and 51, serves to hold the recessed central portions of these brackets into close-fitting engagement with the grooved bearing members23 and 28. The .pins 34, 38 and 51 are each grooved adjacent to their ends in substantially the manner indicated in Fig. 15, so that such end grooves will engage their respective associated brackets to prevent vertical movement by the pins.

Referring now more particularly to Fig. 17, a main circuit 77 is controlled by the running switch 79. The running switch 79 is then sufficient to maintain the armatures 71 in the position illustrated in Fig. 16, and a high temperature-coefiicient resistance 84 is provided in the shunt circuit 78. After current has been directed through the shunt circuit and coil 69 for a short time, the resistance offered by the element 84 increases by reason of the heating thereof, and causes more current to flow through coil 70, thus reducing the holding force exerted by the magnet 68 and permitting the spring 58 to move the starting switch 42 (bracket 41) to open position, as above described. The starting switch will, therefore, not beheld closed for a period sufficient to cause injury to the motor that the apparatus is designed to control.

Fig. 18 shows, in detail, the relation of the coils 69 and 70 to the armatures 71 and 74. WVhen the starting switch is closed and the armature 71 moved to the position shown in Fig. 16, the running switch is caused to close as above explained. The circuit through the coils 69 and 70 is then complete, causing the armature 71 to be retained in thesai-d position until the resistance 84 becomes heated and the flow of current therethrough reduced. This causes an increased flow of current through the coil 70.

The flow of current through the coil 69 being reduced and that through coil 70 increased, and the coils being energized in opposite directions, the differential therebetween that creates a magnetic flux through the core during starting, is reduced a suiti- ,cient amount to permit the spring 58 to open the starting switch against the magnetic force exerted upon the armature 71. The circuit through the coil 69 and the starting winding 81 is then broken, leaving only the coil 70 effective. The coil 70, being in series with the main winding, 82, then acts as an ordinary overload coil and, owing to the remote position then occupied by the armature 71, any magnetic force set up around the core 86 will be exerted mainly upon the armature 74 against the tension of a spring 63a, thus moving the armature 74 against the latch lever 62a. and the tension of the spring 63 to free the running switch (running switch 79bracket 53) from the lever 62 and permitting the switch to be moved to open position b the tension spring 49, as above demovement, the position of the running switch. scribed In testimony whereof, I have hereunto I have, therefore, provided means for insubscribed my name this 13th day of May, suring that the running switch shall notbe 1926. 5 maintained in closed. position so long as an HUBEBT K. KRANTZ. 70

overload obtains on the circuit.

lVhile the device has been described in its application to an alternating current motor, of the induction type, it may be employed in r connection with various other classes of apv 75 paratus wherein primary and secondary circuit conditions exist. 4 I claim as my invention: 1. The combination with a starting switch and a running switch, of a handle for man- 30 ually closing the starting switch, a tension connection between the starting switch and the running switch for biasing the running switch toward the position occupied by the starting switch, means for disengaging the 5 starting switch from the handle when such I switch is closed, means for automatically returning the starting switch to open position, means controlled by the, running switch for p maintaining the handle in its closed position 90 during the time that the said switch is closed, and a tension connection between the starting switch and the handle for returning the handle to its on position when it has been disengaged from the running switch.- v 95 2. The combination'with a starting switch and .a running switch, of a handle for direct- .ly actuating the said switches, means for movingthe starting switch to open positionswltch, and means for returning the handle to its open position when the running switch is opened. 3. The combination with astarting switch 40 and a running switch, of a common mechani- 105 cal means for closing the said switches, means a .for opening the starting switch independently. of the said closing means, and means for opening the running switch whenever the v said closing means is returned to open posi- I tion.

4. The combination with a starting switch and a running switch, of a handle for closing the. said switches, means for moving. the starting switch to open position independently of the handle and the running switch, means for retaining the handle in its closed position while the running switch remains closed, means for automatically opening the no running switch, and means for returning the handle to its open position whenever the running switch is opened. 5. The combination with a starting switch and a running switch,'of a handle for closing 1 I I 12 the said switches, means for opening the Q I starting switch independently of the said closing means and means so associated with the running switch and a handle that the 35 independently of the handle and the running 100 handle indicates, through its associated v V

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