US1796076A - Electric switch - Google Patents

Description

March 10, 1 931. g, BLUME T 1,796,076

ELECTRIC SWITCH Filed March 24, 1930 I'nventofs: Louis F Blume,

Jose h X.Mathieu,

Thaw Attorne g Patented Mar. 10,1931

1 UNITED STATES PATENT OFFICE LOUIS I. IBL'UME AND JOSEPH. x. MATHIEU, OI PITTSFIELD, 'MASSACHUSETTS, AS- SIGI NORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK ELECTRIC SWITCH Our invention relates to switches. In-somc electrical circuits which are controlled by switches, it is desirable that the switch be arranged to operate without interrupting the 6 main current flowing in the circuit. The general Object of the invention is to provide an improved switch having this advantage.

Other objects and advantages will .appear from the following description taken in connection with the accompanying drawing in which Fig. 1 is a side view of a switch. con-- structed in accordance with the invention; Fig. 2 1s a front .view of the switch shown in Fig. 1 but with partof the operating mechanism removed to reveal certain details more clearly; Fig. 3 is a somewhat diagrammatic perspective view of part of the switch and its operating mechanism, the relative proportions and spacing of the parts being different-from that shown in Figs. 1 and 2 in order to explain these parts and their operation more clearly; and Fig. 4 is a diagrammatic view of a circuit in which the switch may be used with advantage.

415 Like reference characters indicate similar parts in the different figures of the drawing.

The invention will be explained in con- 'DQCUOD. with the particular form of switch shown in the drawing. This switch is mounted on a sup orting plate or partition 10 and is enclosed y a casing 11. The switch includes a plurality-of fixed contacts 12, 13,

14, 15 and '16 and two movable contacts 17 and 18. The fixed contacts are connected to terminals 19 on the back of the plate 10.

The movable contacts 17 and 18 are connected by flexible conductors 20 and 21 respectively to contacts 22 on the back of the plate 10.

Each of the fixed contacts includes two pivotally supported contact members aand b which are individually 'yieldable against a spring 23 to assure good contact between the fixed and movable contacts. The two movable contacts 17 and 18.normally make contact with the two members a and b respectively I of the same fixed contact 'as shown in Figs.

2 and 4.

' The movable contacts 17 and 18 are carried by two arms 24 and 25 respectively which ex-' tend from sleeves 26 and 27 rotatable on shafts 28 and 29. Each ofthe arms 24 and 25 includes a section 30 of insulating material to insulate the contacts 17 and 18 from each other and from their operating mechanism.

Each of the sleeves 26 and 27 has an arm 31 with its outer end connected by a link 32 with one arm of a bell crank 33. The other arms of the two bell cranks 33 are connected to the lower ends of the plungers .34 of two solenoids 35 and 36, the solenoid 36 with part of its plunger being removed from Fig. 2 to disclose other parts more clearly. The bell cranks 33 are pivoted on. shafts 37 and 38. The shaft 37 is carried by an arm 39' projecting from a sleeve or hub 40 pivoted on a main supporting shaft 41. The shaft 28 also projects from this same hub 40. The outer ends of the shafts 28 and 37 are braced by a link 64. The shafts 29 and 38 are similarly carried by a second sleeve or hub 42 pivoted on the main supporting shaft 41, the outer ends of the shafts 29 and 38 being braced by a link 43 and the shaft 38 being connected rigidly to the sleeve or hub 42 by an arm 44'. The main shaft 41 is carried'by the base 45 which is secured to the supporting plate 10.

When the solenoid 35 is energized, its plunger will be drawn'up through a distance determined by a stop 46 on the plunger. This motion of the plunger will rock its bell crank 33 about the shaft 37 ,break its toggle connection with the arm 31 and thus move the contact arm 24 forwardly about the shaft 28 contact 18 fromthe member 6 of the fixed contact. The movable contacts 17 and 18 are normally pressed against the members a V gether the movable and fixed contacts in the manner which has been described. The main shaft 41, however, is at right angles to the shafts 28 and 29 and motion of the contact arms 24 and and their movable contacts about this shaft 41 is lateral along the row of fixed contacts. This lateral motion of the movable contacts 17 and 18 is controlled by a disk cam 48 and a spring 49. The cam 48 is carried on a shaft which turns in bearings in the upper-ends of two spaced arms 50 and .51, the cam projecting into the space between the two arms. The arm 50 projects from the hub and the arm 51 projects from the hub 42. The inner face of each arm and 51 is provided with a stop adapted to rest against the adjacent face of the cam 48. The spring 49 tends to force the two arms 39 and 44 apart and thus keep the stops on the arms 50 and 51 in contact with the opposite faces of the cam 48. This cam 48 has alternate thin and thick portions so that rotation of the cam will vary the angular spacing of the arms 50 and 51 and therefore of the contact arms 24 and 25 and of the movable contacts 17 makingposition by a plate 52 having notches and 18. I Each thin portion of the cam 48 is proportioned to space the movable contacts 1 17 and 18 to coincide with the spacing of the two members a and b of any one of the fixed contacts as shown in Figs. 2 and 3. Lateral.

displacement of the twomovable contacts 17 and 18 1s prevented when they are in contact inits edge which are engaged by projections e 53 on the two contact arms 24 and 25, there being a notch for each contact making posit1on of each contact arm. 7

I The solenoids 35 and 36 are ports 54 and 55 respectively projecting from the arms 50' and 51. If either solenoid is energiaed, it attract its plunger and move the corresponding contact arm andmovable contact forwardly as has been described. If

the solenoid 35 shown at the left in F igi 2-is energ1 zed,for.example, thecontact 21111124 with its movable contact 17 will he moved forwardly away from the member a of the fixed contact 14. e As the arm 24 starts to 7 move, its projection 53 is disengaged from the plate 52 after which the iarm24 isfree'to move laterally'iexhept as controlled by the 48 and the spring 49. Further forward. movement of thearm 24 causes a' springp'ressed 56 to engage a tooth of a toothed .wheel-57 nthe adjacent end of the shaft carryingtheoam 48. The parts are proportioned} to turn the cam 48just' far enough to force a thick portlon of the between carried by supstops on the arms 50 and 51. The other contact arm 25 is prevented from moving laterally by the engagement of its projection 53 with the plate 52. The separation of the arms 50 and 51 by the thick'portion of the cam 48 therefore causes the contact arm 24 to move late rally toward the fixed contact 13, the parts being so proportioned that the contact arm will stop with its movable contact 17 directly in front of the member a of the fixed contact 13. The lateral movement of the contact arm 24 starts as soon as its pin 56 reaches the toothed wheel 57 so that this lateral movement takes place while the arm is moving forwardly away from the fixed contact'14. If the solenoid 35 is now deenergized, it will release its plunger 34 and the contact arm 24 will be forced back by its spring 47 with its movable contact 17 against the member a of the fixed contact 13 and with the projection 53 of the arm engaging a notch in the plate 52 to prevent lateral displacementof the arm while in this contact-making position. If the other solenoid 36 is now e11- ergized, it will attract its plunger which will move the contact arm-25 with its movable contact 18 forwardly releasing it laterally from the plate 52. This contact arm 25 has a spring-pressed pin 58 which engages a tooth of a toothed'wheel 59 on the adjacent end of the shaft carrying the cam 48. The cam 48 is turned by the pin 58, the parts being proportioned to turn the cam 48 just far enough to bring its next thin portion between the stops on the arms 50 and 51. This permits the spring '49 to return the contact arms 24 and 25 to their minimum spacing. The. arm 24 being held by the plate 52 against lateral movement, the spring 49 thus moves the arm 25 laterally until its movable contact 18-is directly in front of the member I) in this contact-maln'ng position. This complete s the transfer of the movable contacts from one fixed contact to a second one and itis apparent that the steps described may.

berepeated until the last fixed contact is reached. c I

It has been-seenthat 1f the contact arm 24 is. moved first and the other contact arm 25 last, the movable contacts 17 and 18 will be transferred to the left along the row of fixed contacts and toward the fixed contact 12. If,

however, the contact arm 25 is moved first, it will vbe transferred;to the right and toward the contact1 because during the initial separation of the contact arms the other arm 24 will be held in place laterally by the plate 52 and the arm 25 be forced to the rightbythe cam 48. Subsequent transfer of.

minim 24 will also'be a; the right while v the arm 25 is held laterally by the plate 52.

18 is thus dependent wholl of their. transfer or, h

' ,ferred first.

A well known and commonly used circuit in which the switch which has been described may beused with advantage is shown diagrammatically iii Fig.4. In this arrangement, one of the windings 60 of a transformer is provided with taps connected to the fixed contacts 12 to 16 inclusive .ofthe switch. The movable contacts 17 and 18 'of the switchconnect oneof the fixed contacts to the opposite end terminals of a reactance 61, the center of the reactance being connected to one side 62 of an outside circuit. The other side 63 of this circuit is connected to the opposite end of the transformer winding 60. The current through the switch thus normally flows in opposite directions through the two halves of the reactance which may be wound to neutralize each other. During a transfer of themovable contacts of the switch from one fixed contact of the switch to the next' and while the movable contacts are on adjacent fixed contacts, the voltage between the two fixed contacts will tend to force a circulating current in the same direction through both halves of the reactor. The current in the two halves will not be neutralized but will be'limited by the reactance to a safe value. The object of changing the position of the movable contacts'is, ofcourse,

to regulate the voltage ratio of the transformer. i

The invention has been explained by describing and illustratin a particular form and application thereof ut it will .be apparent that various'chan es may be made without departing from t e spirit of the inventlon or the scope of the appended claims.

What we clalm as new and desire to secure I by Letters Patent of the United States, is

1. A switch including a plurality of fixed contacts, two movable contacts, means for transferring one of said movable contacts and subsequently the other of said movable contacts in the same direction along said fixed contacts, and means responsive to the order of transfer of said movable contacts for controlling the direction of transfer thereof.

ing a*;.contact,'a' pl'uraliin of fixed contacts, meansjfor moving-said contact arm forwardly to separate its contact from one of said fixed contacts, and means controlled by said movable arm to move itself laterally alongv said fixed contacts durin itsforward movement. 4. A'switch' inclu ing a plurality of fixed contacts, two movable contact arms carrying contacts, a pivotal s'u port for each arm for forward movement 0 the arm away from a fixed contact, said pivotalsupports being carriedby another pivotal support for lateral movement of the arms along said fixed contacts.

5. A switch including a plurality of .fixed contacts, two movable contact arms carrying contacts, a pivotal support for each arm for forwardmovement of the arm away from a fixed contact, said pivotal supports being carried by a common pivotal support for lateral movement of the arms along said'fixed'contacts, means for movin the arms laterally, and means carried by eac arm for controlling its lateral movement.

6. A switch including a plurality of fixed contacts, two movable contact arms carrying contacts, a pivotal support for each arm for forward movement of the arm away from afi-xed contact, said pivotal supports being carried by a common pivotal support for lateral movement of the arms along said fixed contacts, a stop connected to each contact arm, a cam engaging said sto sto vary the spac ing of said arms, means or moving each arm,

forwardly, and means controlled by said arms to operate said cam during the forward motion of the arms.

7.. A switch including a plurality of fixed contacts,*two movable contact arms carrying contacts, a pivotal su port for each arm for forward movement 0? fixed contact, said pivotal supports being carried by a common pivotal support for lateral movement of the arms along said fixed contacts, a stop connected to each contact arm, 1

a cam engaging said stops to vary the spacing of said arms, toothed wheels connected to said cam, a pin carried by each arm for engaging one of said toothed wheels during forward motion of the arm to vary the spacing of the arms, and means for preventing -lateral movement of each arm while enga ing a fixed contact.

8. A switch including a plurality of fixed contacts, two. movable contact arms carrylng contacts, a pivotal support for each arm for forward movement of the arm away from a fixed contact, said pivotal supports being carried by acommonpivotal support for lateral movement ofthe arms along said fixed con- .tacts, a stop connected to each contact arm, a cam between said stops to vary the spacing the arm away from a of said arms, toothed wheels comiected to said

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