US1745554A - Switch mechanism - Google Patents

Description

Feb. 4, 1930. l.y N. OGLEVEE SWITCH MECMNISM Filed March 2s. 192s s sneetssheet 1 l Feb. 4, 1930. l, N, OGLEVEE 1,745,554

SWITCH MECHANISM 'Filedmarch 2s. 1928 s sheets-sheet 2 Feb. 4, 1930.A l l. N. o'GLEvEE 1,745,554

SWITCH MECHANISVM ,Filed Maren 2s, 1928 s sheets-sheet S Patented Feb. 4, 1930 UNITED STATES PATENT OFFICE ISAAC NEWTON OGLEVEE, OF MOORES, PENNSYLVANIA, ASSEGNOR TO FRED' C. OSTERHAUT, OF PHILADELPHIA, PENNSYLVANIA SW'ETCEI MECHANISM Application led March 28, 1928.

The present invention relates to switch mechanisms and more particularly to automatic switches for controlling energization of auxiliary and main circuits, such as startlng and ruiming circuits of an electric motor'.

This application is a continuation in part of the application of Oglevee, Serial No. 7 8,- 437, filed December 30, 1925.

rThe principal object of the present inven 1g tion is to provide a simple automat-ic switch mechanism by which the closing of a main circuit may be caused to occur at a pr-edetei-mined time following the energization of an auxiliary circuit.

Another object of the present invention is to provide a switch, particularly useful as an automatic starting switch for electric motors, whereby the cycle of starting operations is repeated in the event of improper energization of the main circuit through failure to attain speed or because of overload.

lith these objects. in view, the principal feature of the present invention comprises an automatic switching mechanism adapted for energization of an auxiliary and a main circuit and including a main relay having an armature with provision for a slow movement to close the main circuit at a prede termined time following the closing of the auxiliary circuit. The slow movement of the armature is effected by means of a magnetic brake which is brought into action immediately upon energization of the main relay and which is preferably released immediately prior to the limit of movementof the armature in order to effect a desirable quick closing of the main circuit.

Another feature of the invention comprises an overload device which operates upon the occurrence of excessive current in the main circuit to open the main circuit and automatically to restore operation of the starting or auxiliary circuit whereby the cycle of operations is repeated. This overload control is especially useful in connection with electric motors in that if the motor fails to attain speed in the first actuation of the starting winding, it will permit throwing out of the main switch and render the starting circuit again operative, repeating this cycle Serial No. 265,275.

of operations until the motor finally attains ruiming speed or the main fuses are blown.

Other features of the invention consist of certain novel features of construction, com binations and arrangements of parts hereinafter described and particularly defined in the claims.

In the drawings illustrating what is now considered the preferred form of the invention, Fig. l is a side elevation of the switch mechanism; Fig. 2 is a plan view of the apparatus shown in Fig. l; Fig. 3 is a side elevation of the apparatus viewed from the opposite side; Fig. 4 is a front end elevation; Fig. 5 is a rear end elevation; Fig. 6 is a detail view partly in section showing the operation of the main armature; and Fig. 7 is a diagram showing the connections as a starting switch for a split phase induction motor.

The illustrated embodiment of the invention comprises a switch mechanism comprising a switch adapted to be selectively thrown to close an auxiliary circuit and a main circuit. rThe switch is thrown in one direction or the other by means of relays, one of which controls the auxiliary circuit and the other the main circuit. The main relay is provided with an armature of peculiar form having a flat face adapted to engage a cooperating pole face of the relay magnet and a curved extension opposed to another pole face of the magnet and so arranged that the air gap between the magnet and the armature extension decreases as the armature projects the magnet. This construction affords a long throw for the armaure and permits accurate governing of the time of closing of the main switch through the medium of a magnetic brake. This brake comprises an armature, which is connected to the main relay armature and which is drawn across the pole face of a brake magnet when the main relay is energized. The starting relay is illustrated as being of identical form with the main relay except that inasmuch as a quick closing auxiliary circuit is desirable, no brake is provided therewith. As illustrated and described herein, the switch mechanism is particularly designed as a starting compensator for an electric motor. In the event that the motor tails to obtain speed ai'ter energization of the starting circuit an overload coil in the running circuit serves to trip the main relay, whereupon the cycle ot operations is repeated as many times as may be necessary to bring the motor torunning speed or until the fuses or main circuit breakers are operated to open the line.

Referring to the drawings, the switch apparatus comprises a switch 10 having two parallel arms connected to an insulating block 12 which is pivoted at 14 on top of a panel The switch arms carry at their ends contacts designated as 18 and 20, the former constituting the auxiliary circuit contacts and the latter the main circuit contacts ot the apparatus. Cooperating with the contacts 18 are a pair vot stationary contacts 22 while a pair of stationary contacts 24 are arranged directly below the contacts 20. rlhe block 12 is normally supported in neutral position as shown in Fig. 1 by an arched spring 26 having its central portion secured to the panel -and its ends pressing against the under side ot' block 12. The block is provided with two downwardly extended projections 28 and 30l which are adapted to be engaged by the relay armatures to throw the switch into either starting or running position.

vThe switch is closed on the auxiliary contacts 18 and'22 by means of the auxiliary relay and on the main contacts 2O and 24 by means ot the main relay. These relays as herein described are of identical ormand a description of one will sutiice.

As shown in `Fig. Y1, the main relay comprises an electro-magnet 32 having a core 33 terminating in a pole piece 34 with a vertical pole tace 36 and a horizontal pole tace 38. The magnetic circuit of the magnet comprises the core 33, an upright laminated leg 35, a horizontal leg 3T, and the armature 39. The core and armature are supported in a trame ot non-magnetic material comprising two brackets 40 supported from the panel 16. The armature is pivoted at 42 between the brackets. The armature comprises an upright portion having a fiat face 44 adapted o engage the vertical pole face 36 ot'the Vmagnet and a curved extension 46 formed on an arc eccentric to the pivot 42 and so constructed that as the armature is attracted to the magnet the air gap between the extension 46 and the pole iace 38 decreases. The position et the armature at the limit of its attracted movement is shown in Fig. 6, `The lower leg 37 of the core is formed with a curve 48 which cooperates with a curved extension 30 ot the armature, the extension 50 being` eccentric to the curve 48 in order'that the air gap at this vpart ot the armature may also decrease as the armature is attracted. The provision et such decreasing air gaps insures positive movement Ot the armature towards the magnet, inasmuch as the armature tends to move to such a position as to make the reluctance of the magnetic circuit a minimum. The upper end ot the armature is arranged to strike the lower projecting part 30 of the switch block 12 to rotate the switch into such a position as to cause the contacts 20 and 24 to engage.

The starting relay is similarly formed with a coil'52, a core 54, and an armature 56, and is mounted in brackets 57 on the opposite side of the panel. The positions of the two relays are reversed in such a manner that they operate to move the switch 10 in opposite directions, the starting relay serving' to close the left-hand contacts and the running relay the right-hand contacts as'viewed in Fig. 1.

in operation, the coils 32 and 52 of the main and auxiliary relays are simultaneously energized and act immediately to attract their respective armatures. The armature 56 ot the starting relay is attracted immediately to such a position that the starting contacts 18 and 22 are brought into engagement. The main armature 39, however, is retarded by means ot a magnetic brake in order that the main contacts 20 and 24 may not be closed until the auxiliary contacts have remained in closed position tor a time. This brake, which is indicated generally at 58, comprises a magnet coil 60 having a magnet core 62, the core cooperating with an armature 64 which is drawn across the ends of the core as the main armature 39 is moved. One leg of the core is connected by a pivot pin 66 with an extension 68 of the main brackets 40. The three legs ot the core are mounted in a frame 70 ot nonmagnetic material such asbrass, and the armature is enclosed between a pair of brass arms 72 which are extended at one end to form a yoke 74 embracing opposite sides of the armature 39 and pivotally connected thereto by a pin 76. rlhe brake magnet coil 60 is connected in series with the starting relay coil As the main armature is attracted by energization of the relay coil 32, its motion is retarded by the attraction between the brake magnet and its sliding armature. In order that the main armature 39 may accelerate to produce a quick closing action ot the switch as the armature approaches the end oi its movement, the brake armature 64 is undercut asindicated at 80 in Fig. 6 to form an air gap and the righthand end 82 of the armature is so disposed withv relation to the magnet core that the attraction for the brake arma-ture is prac.

tically released after the main armature has traversed the major part of its movement. Practically simultaneously with the engagement of the main armature 39 with the switch actuating extension 30, the starting coil 52 is de-energized in order that the starting armature 56 may be released, thus freeing the switch and permitting it to be thrown into tri Cri

closed position by the action of the main armature. This cle-energization of the starting' relay is effected by a switch 83 having a fixed contact 84 supported on an insulated bracket 86 attached to the bottom part of the main bracket and a movable Contact 88 which is mounted on an insulatingl block 90 pivotally mounted in ears 92 depending from the main bracket. The right-hand end of the block 90 as viewed in Fig. 1, lies in tie path of the extension of the main ariature. The action ot the main armature in being attracted to the magnet is to open the switch 83, which is in series with the starting relay. A coil spring 94, bearing between the core 35 and the block 90, operates to maintain the switch 83 normally in closed position. lnasmuch as the brake coil is in series with the starting winding 52, this coil is also cut out of circuit, although it is not necessary that the coil 60 be cle-energized in order to eifect quick closing of the switch because the provision of the air gap in the bra-lie armature is sufficient to accomplish this purpose. However, the de-energization of the brake coil on closing of the main switch results in some saving oi power.

Upon the closing of the main contacts 20 and 24, the main or running circuit is energized, the armature 39 being retained against the pole piece 34. W'hen the switch mechanism of the present invention is employedv with alternating currents, it is desirable to provide a closed electrical circuit oit' good conducting material adjacent to the pole piece ot' the main relay 52, in order to prevent chattering ot the armature. This is accomplished by connecting shading pieces 96 to opposite sides of the pole face by means of bolts 98. Similarly, the pole piece of t ie starting relay is shaded with brass or copper plates. However, it is desirable that the shading be not too great, otherwise the magnetic attraction will be decreased and the loss ot' power too great. Therefore, if the main brackets 40 are or" brass, as is desirable, they are connected together through the core by bolts 100 which are insulated from the core by non-conducting bushings and from the brackets by insulating' washers 102.

In the eventthat the operation of the starting switch tails to bring the circuit into suitab e condition for running operation, an overload device indicated generally at 104 is operated to throw out the main armature 39 and pern'iit reestablishment ot starting conditions. This is likely to occur in case the mechanism is employed to start an electric motor which maybe under a sufficiently great load to prevent its coming to running speed within the time allowed for 'the attraction of the main armature. The overload device comprises an overload coil 106 in series with the main circuit, The coil has a core adapted to attract a magnetic armature 108 which is pivoted at 110 on a bracket 112 depending from the panel 16. The coil 106 is mounted in a bracket 114 which is also attached to the panel and has a lateral extension 116 on its lower end to receive an adjusting screw 118. The end ot the armature directly beneath the coil 100 rests on the top ot the adjusting screw and by variation in the position of the screw, the initial position of the armature may be raised or lowered to permit operation ot' the overload device at any predetermined value of current. T he armature, on being attracted to the overload coil, trips an overload switch having a fixed contact 120 and a spring contact 122, both of which are supported on an insulating block 124 and supported on the bracket 112. The lower spring contact 122 is disposed in the path of the armature 108. The switch is connected in series with the winding of the relay 32 in order that the main armature may be released when the overload device is operated. A. latch 126 is pivoted on a block 128 secured to the bracket 112. The latch has a depending projection 129 which normally abuts the end ot the armature 108 when the main armature 39 is attracted by the relay. As the main armature is attracted to its coil, the projection 129 on the latch drops against the end of the armature, as shown in full line position in Fig. 6. and so longas the current in the running circuit remains below the predetermined value tor which the armature is set to operate, the latch and the overload armature occupy this position. Upon attraction ot the overload armature to the position shown in dot and dash lines in Fig. 6 due to overload, the latch tails by its weiglit and the projection 129 moves over the upper end of the armature, thus preventing its return to initial position until the main armature 89 again strikes the latch. lVhen the overload device is operated, Jdie main relay is Cle-energized and the armature 39 moves back by gravity to its original position. The switch contacts 84 and 88 arc again closed and the starting relay and the brake coil are again energized, thereby closing` the starting circuit on contacts 18 and 22. The circuit through the main relay 32 is not again established until the main armature strikes the latch 126 to close the contacts 120 and 122 of the overload switch, whereby the main armature is again attracted and the cycle of operations is repeated. By employing' an overload device in which the latch is set upon actuation of the switch and is re leased by the main armature, it is necessary for the main armature to traverse a complete iovement back to its original position, and then again toward its magnet. This insures a considerable time of movement during which the starting' or auxiliary circuit is energized because the main armature is retarded in both movements' bv the action of the magnetic brake 58. It an excessive current is flow ing in the running circuit upon closing of the main contacts for the second time, the circuit will again trip and place the auxiliary circuit in operation, and this action will be repeated for number of cycles until the main circuit current is reduced to a safe value or until the main fuses are blown. The overload device is also useful as a safety device when the motor is in operation because upon the occurrence of a temporary overload, the main circuit is opened and the starting circuit'is thrown into operation until the running circuit may again be safely energized.

Circuit connections for operation of a split phase induction motor are shown in Fig. The alternating current lines 130 and 131 include a manually operated switch 132. The motor is diagrammatically indicated bythe starting winding 133 and the running winding 134. A phase shifting resistance 135 is included in the starting circuit in series with the starting winding 133. For starting purposes, both windings are energized and after the motor reaches speed, only the main winding 134 is supplied with current. The line 131 is connected to both ofthe arms 10 of the main switch. Une of the auxiliary Vcontacts 22 connects by a wire 136 with the starting circuit which includes the starting winding and the phase shifting resistance. The other fixed contact 22 connects by a wire 137 with the winding 131i. The common connection of the windings 133 and 134 connects with the line A130. The starting relay winding 52 and theniain relay winding 32 are adapted for connection across the lines. A switch 138 is connected between the line 130 and a common connection ruiming to the coils 32 and 52. This switch may be manually operated in which case it controls the operation oi' the motor as effectively as the switch 124C, but is specially provided for the purpose of automatically controlling the starting and stopping of the motor. Y In refrigerator installa` tions, for example, it may consist of a thermostatically controlled switch of any usual or preferred form. The starting winding 52 is connected in series with the brake coil 60 and the switch 83. The running relay coil 32 is connected in series with the overload switch contacts 122 and'124. The stationary main contacts 24 are connected in series with the overload coil 106 to the main winding 134. Then the switches 132 and 138 are closed, the relay windings 32 and 52 and the brake winding 60 are energized. The starting armature immediately closes the switch 10 on the ccn tacts 22 and circuits are established through the starting and running windings 133 and 134 of the motor. The main armature 39 is attracted by the coil 32 and prior toV engagement of the armature with the actuating projection 30 of the switch block, it opens the switch 83, thereby (le-energizing the coils 52 and 60 and permitting quick closing of the switch 10 on the running contacts 24. The starting winding 133 is then out of circuit and a complete circuit is formed through the line 130, the winding 134 or the motor, the overload coil 106, contacts 24, switch 10, and the line 131. It will be seen that the overload coil is not included in series with the contact 22 so that during starting when a high current necessarily Flows, the overload device is not operative to open the main relay circuit.

Although the invention has been described as employed Jfor a starting switch for a single phase motor ci the split phase type, it is not limited'to such use but may he employed as a switch for controlling the energization of auxiliary and main circuits oi' any type of electrical apparatus.

The invention having been thus described, what is claimed is:

1. A switching mechanism comprising a switch having starting and running contacts, means for closing the switch on the starting contacts, a relay including a coil and an armature, means for energizing the relay to attract the armature, magnetic means for retarding the movement of the armature on energization of the relay, and means operated by the armature as it approaches the limit of its movement for closing the switch on the running contacts.

2. A switching mechanism comprising a starting circuit and a running circuit,'a running circuit relay including a magnet and an armature, means for closing the starting circuit and for simultaneously energizing the relay, magnetic means for retarding' the movement of the armature toward the coil when the relay is energized, and means operated by the armature as it approaches the limit'or" its movement for closing the running circuit.

3. A switching mechanism comprising a starting circuit and a ruiming circuit, a running circuit relay including Va magnet and an armature, means for closing the starting circuit and for simultaneously energizing the relay, magnetic means tor ret-arding the movement of the armature toward the magnet when, the relay is energized, means for releasing the retarding means as the armature approacnes the limit ot its movement, and means operated by the armature for closing the running circuit.

el. A switching mechanism comprising a stai-ting circuit and a running circuit, a starting` relay including an electro-magnet and an armature, a main relay including an electro-magnet and an armature, means for energizing the relay electromagnets, magnetic mears for retarding the movement of the main armature, means operated by the main armature for closing the running circuit as the armature approaches the limit of its movement, and a switch operated by the main armature for de-energizing the starting relay 5. A switching mechanism comprising a relay including an electro-magnet and an armature, a brake consisting of a magnet and an armature, means for connecting the brake armature to the main armature to slide the brake armature across-the pole tace ot the brake magnet, switch cont-acts, and means for closing the contacts as the main armature approaches the limit of its movement.

6. A switching lmechanism comprising a relay including an elcctro-magnet and an armature, a brake consisting of a magnet and an armature, means tor connecting the brake armature to the main armature to slide the brake armature across the pole tace of the brake magnet, switch contacts, and means for closing the contacts as the main armature approaches the limit of its movement, the brake armature being constructed and arranged to release the braking action near the completion ot movement ot the main armature.

7. A switching mechanism comprising a relay including an electro-magnet and an armature, a brake consisting ot a magnet and an armature, means tor connecting the brake armature to the main armature to slide the brake armature across the pole tace of the brake magnet, switch contacts, and means Jfor closing the contacts as the main armature approaches the limit ot its movement, the brake armature having a portion termed with an air gap with relation to the pole tace of the brake magnet to release the braking action near the completion of movement ot the main armature.

8. A `switching mechanism comprising a relay including a main electroanagnet and a main armature, means for energizing the magnet to attract the armature, a brake including a brake electro-magnet and a brake armature, means for connecting the brake armature to the main armature to move the brake armature across the pole face ot the brake electro-magnet upon movement ot' the main armature, a main switch adapted to be closed by the main armature near the limit ot its movement, a-nd a switch in series with the brake electro-magnet and operated by the main armature to release the braking action and Vto accelerate closing of the main switch.

9. A relay comprising a magnet having a pole piece, a pivoted armature having a tace adapted to engage the pole piece and provided with a curved extension eccentric to the armature pivot and constructed and arranged to provide a 'decreasing air gap between lthe curved extension and the pole piece ot the magnet as the armature is attracted to ,the magnet., .and a switch .adapted to be closed by the armature.

10. A relay comprising an electro-magnet having a pole piece with pole faces at substantially right angles to each other, a pivoted armature having a flat tace adapted to engage one of the pole faces ot the magnet and a curved extension cooperating with the other pole tace and formed on a curve eccentric to the armature pivot to decrease the air gap between the magnet and the curved Aextension as the armature approaches the magnet, and a switch adapted to be closed by the armature.

ll. A switching mechanism comprising an electro-magnet having a pole piece, a pivoted main armature having a face adapted to engage the pole piece and provided with a curved extension eccentric to the armature pivot and cooperating with the pole piece t0 provide a diminishing air gap as the armature is attracted by the magnet, a magnetic brake including a core and a cooperating armature connected with the main armature to retard the movement of the latter, a switch adapted to be closed by the main armature, and means for releasing the braking action ot the magnetic brake prior to closing ot the switch.

l2. A switching mechanism comprising a relay electro-magnet having va pole piece with pole faces substantially atright angles to each other, a pivoted main armature having a vflat tace adapted to engage one ot the pole 'l'aces of the magnet and a curved extension cooperating with the other pole face and curved eccentrically with relation to its pivot to provide a diminishing air gap as the armature is attracted to the magnet, a magnetic brake including' an electro-n'iagnet and a brake armature` means connecting the brake armature with t-he main armature to retard the motion ot' the latter, the brake arma-ture being provided with an air gap adapted to be introduced into the circuit of the mag'- etic brake as the main armature approaches the relay magnet, vand a switch Yadapted to be closed by the main armature.

13. A switching` mechanism comprising` a pivoted switch block, switch ari-ns mounted on the block, a plurality ot' sets oit contactsI cocperating with the switch arms, a star-ting relay adapted to close the switch on one ot the sets of contacts, a main relay adapted te close the switch on another of the sets ot contacts, the main relay including an electromignet. and an armature having a part to engage the pivoted switch block, and means Jfor releasing the starting relay as the main armature approaches engagement with the switch block.

la. A switching mechanism comprising a panel, a switch block pivoted on the panel, a starting relay yand a main ,relay each comarising an `electro-magnet and an armature, the switch block having projections adapted to be engaged by the armatures and to be moved in opposite directions thereby, means for simultaneously energizing both electro- Amagnets to attract the starting and main Y projection.

15. A switching mechanism comprising an electro-magnet, an armature adapted to be attracted by the magnet, an overload switch including a coil and an armature, a latch having means for holding the overload switch open and adapted to be engaged to close the overload switch upon return of the main armature to its original position.

16. A switching mechanism comprising a main switch, an electro-magnet, an armature adapted to be attracted by the electro-magnet and to lengage the main switch, a switch contact upon which the main switch is closed, an overload'coilin series with the contact, an overload armature, an overload switch in series with the electro-magnet to cle-energize the latter when the overload armature is attracted, a latch adapted to hold the overload armature in a position to maintain the overlo-ad switch open after actuation of the overload coil. and constructed and arrange-d to be released upon return of the main armature to its original position to permit closing of the relay.

17. A switching mechanism comprising a switch block, auxiliary and main contacts associated with the switch block, a starting relay and a main relay adapted to close the switch block on the auxiliary and main contacts respectively, each relay including an electro-magnet and an armature, an overload circuit breaker having a coil in series with the main switch contact and an overload switch in series with the main relay, means for retarding the movement of the armature of the main relay, a switch in series with the starting relay and operated by the main relay armature to release the switch block as the main relay armature approaches closing position, and a latch to hold the overload circuit breaker in open position and constructed and arranged to be released by the main armature as the'latter approaches its initial position. Y y

18. A switching mechanism comprising main and auxiliary contacts, means for closing the auxiliary contacts, a relay having an armature acting to close the main contacts, means for energizing the relay to attract the armature when the auxiliary contacts are closed, .and means for retarding the armature to cause it to beattracted slowly for the greater portion of its movement and having provision for permitting accelerated movement thereof as it approaches the limit of its movement to close the main contacts quickly. a I

19. A switching mechanism comprising a switch having main and auxiliary contacts,

means for closing the auxiliary contacts,

armature acting to close the main contacts,

means for energizing the relay to attract the armature when the auxiliary contacts are closed, and magnetic brake means for retarding the armature to cause it to be attracted slowly for the greater portion of its movement and having provision for being released to permit an accelerated movement of the armature as the armature approaches the limit of its movement to close the main contacts quickly. l

Q1. A switching mechanism comprising main and auxiliary contacts, means for closing the auxiliary contacts, a relay having an armature acting to close the mainV contacts, means for energizing the relay to attract the armature. when the auxiliary contacts are closed, an overload device, means for de-energizing the relay when the overload device operates, means operated by the armature upon substantially the limit of its return to retracted position for again energizing the relay, and means for retarding the armature in either its attracted or retracted movement, said means having Vprovision for permitting accelerated movement of the armature when the armature is near its closed position whereby the main contacts may be opened or closed quickly.

22. A switching mechanism comprising main and auxiliary contacts, means for closing the auxiliary contacts, a relay having an armature acting to close the main contacts,

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