US1998810A - Electromagnetic device - Google Patents

Description

April 23, 1935. B. E. GETC HELL ELECTROMAGN TIC DEVICE Original Filed Jan. 15, 1930 2 Sheets-Sheet 1 April 23, 1935. B. E. GETCHELL 0 ELECTROMAGNETIC DEVICE I 7 Original Filed-Jan. 15, 1930 2 Sheets-Sheet 2 INVENTOR BENJAMIN E. ETOHELL,

Patented Apr. 23, 1935 I UNITED STATES PATENT OFFICE mcraomcnaric DEVICE I Benjamin a. Getchell, Plainville, Conm, assignor to The Trumbull Electric Manuiacturing Compfi, 1;lainville, Conn. a corporation of Conn on Original application January 15, 1930, Serial No. 420,929. Divided and this application November 19, 1932, Serial No. 643,317

6 Claims. (01. 175-330) My invention relates to magnetically operated vide means to allow the normally stationary switches and particularly to an electro-magnet member of the magnet to recede to a limited construction which is specially adapted for use extent to check the impact of the movable memin connection with switch constructions similar her in response to a greater impact than can be to-the type disclosed in my Patent No. 1,714,085. absorbed by the magnetic braking grip between This application is a division of my application the armature and the core of the magnet. Serial No. 420,929, filed January 15,1930,; issued Another object is to provide an operable elecas Patent No. 1,893,827 on January 10, 1933. tro-magnet in which one of the movable mem- Electro-magnetic switchesvof the type referred bers oi the magnet .may have a lost-motion conll') to. are necessarily made up of a comparatively nection with a movable switch member or a 10 large number of parts including stationary and similarly operated device so that the movement movable contacts, connectors, bolts, screws, etc., of the part to be pe l not begin until and the hammer-like blows of an ordinary electhe operating part of the magnet has already 4 tro-magnet in the circuit closing movement tends attained substantially full speed in its operating to loosen some of these parts to aserious extent movement. 15 especially when the magnet is rigidly connected Another object is to provide an electro-magto the movable switch contacts or is mounted netic opera mechanism which ay be made, directly on; the switch base or on a part of the assembled and opera y tested ndep nd ly f enclosing box. the device which it is intended to operate and The principal object of my invention is to pro which may readily and operably be connected 20 vide an electro-magnet construction suitable for to or disconnected from the device. use in operating switches of the type referred Another object is to provide an electro-magto, or other. similar devices, and which may be netically operated switch construction in which associated with such devices and operated with the switch, including'all of its directly related considerable 'force without transmitting any parts, may be assembled as aunit and in which 25 harmful shock to itself or to the device to be the electro-magnet, including all ofits directly operated or to the enclosure in which the conrelated parts, may beassembled as another instruction is housed. I dependent unit and in which the switch unit and Another object is to provide an electro-magnet the magnet unit may be readily connected for unit having an armature and a magnet consistservice or use. l

ing of a coil and a core, the core having one or In carrying out the invention in its preferred mOre armature ing legs and in which conform I provide switch mechanism having stastruction, the "parts are so mounted and co-retionary and movable contacts supported by an lated that the operating force or impact will be insulating body, the parts being constructed and absorbed by the members of the unit without assembled as a unit. I also provide an electro- 35 transmitting any harmiul shock to the other asmagnetic actuating member which is constructed Sociated Part5 d ces. and assembled as an independentnunit. Both of Another object isto provide an electro-magnet the units are supported by a common plate-and construction in which the armature and the mag-- are so relatedthat, when installed for service, 40 net with its core are independently and pivotally gravitytends to hold the parts of the switch and 40 a mounted with their respective axial centers the parts of the electro-magnetic mechanism in spaced soiar apart that when thearmature en-' the open circuit or Oil position. .The electrogages the core of the magnet or vlce-versa, it magnetic device for actuating the switch proper will be with a pivotal motion and also with 9. includes a pivoted or hinged core member and an 46 sliding or surface wi-p movement as soon-as independently pivoted or hinged armature memthe parts have come intocontact witheach ber. Both of-these members are so mounted as oth Y. I to tiltforwardly at their upper ends away from Another object is to provide an electro-magnet the back'plate n a l i in their w ng construction in which, in the circuit closing movements by suitable stops. They are so conmagnet will engage with a sliding surface action ture member first moves rearwardly towards-the in such a manner that the operating shock or core member which, by reason of its stop, reimpact will be'partly absorbed by the magnetic mains stationary until the armature actually grip between the armature and the core of the strikes it with all of its momentum less the magmovement, the armature and the core ,of the 'structed that when the circuit is closed the arms.- 50

magnet and a directly related object is topronetic braking torce caused by the sliding or wiping engagement of the armature and the core and which wiping engagement is due to the fact that the armature and the core are pivoted at spaced apart axial centers. When the magnet is tie-energized, the core remains stationary by' reason of its stop but the armature swings forwardly to the open circuit position and, by reason] of its connections, simultaneously moves the switch contacts into the Off position.

Fig. 1 is a front view showing a switch with the electro-magnetic actuator.

Fig. 2 is an exploded perspective view of the parts of the electro-magnetic device.

Fig. 3 is a view of the right hand side of the net take when the armature strikes the magnet.

Fig. 6 is a plan view showing a fragment of the switch with the magnetic elements.

In the prefered form of construction the stationary and movable parts of the switch mechanism as well as the actuating mechanism are all supported directly or indirectly by a back plate II] which is adapted to be suitably secured in a vertical position when in service and usually in an enclosing or protecting box or receptacle.

A body member I I formed preferably of molded insulation is secured in any suitable manner to the side plates I2 and I3 which in turn are secured to the back plate, for instance, by screws such as I4.

The switch illustrated is for a three-wire system but so far as the invention herein claimed is concerned the number of switching units embodied in the construction is immaterial. It will therefore be necessary to describe only the units necessary for controlling a single circuit. The line terminal I6 is connected to the stationary switch contact I! and suitably anchored to the insulating body. The lower stationary switch contact I8 is connected in a suitable manner with the lower load terminal I9. The front view of two stationary contacts I1 and I8. similar to contacts I! and I8, is shown at the left of Fig. l. The movable contact member is slidably supported on a stud 2| which is carried by the insulating cross bar 22 which is interposed between the upper and lower stationary contacts. Each movable switch member is provided with a resilient abutment spring 23 interposed between the reinforcing member '24 and the washer 25. The insulating cross bar 22 is provided with projecting lugs 26 which are guided in inclined slots 21 formed in the side plates I2 and I3 respectively. When the parts are supported in their normal manner gravity tends to hold the cross bar 22 and all of the attached switch members in the open circuit position.

. A crank shaft 30 is pivotally supported in the side plates I2 and I3 and has crank arms 3| hinged to the links 32.which in turn are connected to' the lugs 2Gjwhich project from the opposite ends of the cross bar 22. The crank shaft 3!! also has an elongated arm 33 which extends laterally through an opening in the side plate I3 to facilitate connection with operating I means. When the arm 33 is pressed rearwardly the crank shaft 30 turns on its axis and draws the two links 32 and the attached cross bar 22 rearwardly. In this movement the movable switch contacts 20 engage the stationary switch contacts I! and I8. As therotation of the crank shaft is continued the cross bar 22 moves further rearwardly carrying with it the studs 2| which draw the washers and the springs 23 to provide increased pressure 5 on the movable switch members. When pressure on the crank shaft is released gravity tends A to bring the movable switch members and the supporting cross bar outwardly to break the circuit. This movement is accelerated by the ac- 10 tion of the springs 23 so as to ensure a prompt and effective breaking of the circuits through the respective switch units.

back plate Ill by screws such as 35. The magnet core is of suitable construction and in the pre- 25 ferred form has the three legs 38 and 38 and 39.

In the form shown the core is laminated and provided with side bars 40 all riveted or otherwise suitably secured together. The lower ends of these side bars are hinged to a pin H which is supported in the post members 31. The swinging movement of the magnet core is limited at the upper end in the forward direction by the lugs 42 which act as abutments for the outer ends of the side bars 40. The back plate serves as 35 an abutment to limit the rearward movement of the magnet core. The location of the parts is such that the weight of the core together with the weight of the coil 43 tends to swing and to hold the magnet core forwardly. The coil is suitably connected in circuit to be controlled manually or automatically in any suitable manner.

The armature member also includes a channellike carrier 44 having arms 45 hinged to a pin 46 5 carried by the outer ends of the posts 31 independently of the hinging of the core member. The armature bar 41 is loosely carried by a hinge .pin 48 between the flanges 49 of the carrier so that the armature is free to adjust itself to the 5 faces of the core. A link 50 has its rear end detachably hinged to the arm 33 of the crank shaft 30 and has-its front end provided with a lost motion means of connection with the upper end of the armature member.

This connection is affected by a pin 5| carried by the lugs 52 and slidable in the-slot 53. The outer end of the link 50 is loosely positioned between fingers 54 at the upper end of the armature carrier. The parts of the armature are. so 0 disposed as to bring its entire weight forward of the hinge pin 46 so that gravity tends to swing the armature and to hold it in the open circuit or Off position in the same way that gravity tends to-hold the magnetic core member forwardly.

When the magnet is energized either by local or remote control of its circuit the armature is of course drawn toward the core member. During the first part of its movement-the magnet has to move'only the armature member but as 70 soon as the pin 5| strikes the rear end'of the slot 53 in the switch connecting link 54,- themagnet tends to rock the crank shaft 3| and move the switch members to the'closed circuit position. The first resistance met (other thanithe resistance. 78

core so securely with a frictional braking action that the magnet frame will not be forced to any great extent away from its position with its side bars 40, 40 at rest against the stop lugs 42, 42.

Because of the fact that the armature frame and the magnet frame are pivoted at spaced apart axial centers, it is obvious that after the armature and the magnet core have been brought together, any further rotary movement of the parts in the circuit closing direction will cause a wiping or sliding engagement between the face of the armature and the contacting surface of the legs of the magnet core. It is also obvious that the strength of the magnet will constantly increase from the moment the armature begins to move until, just before the armature actually makes contact with the core of the magnet, it will be at substantially its full strength and ready to brake or prevent any sliding movement of the engaging portions of the magnet numbers after they have been moved into actual-contact; under some conditions however, the impact of the armature may be great enough to overcome-the braking force of the magnet and may force the frame of the magnet backwardly away from its stop lugs 42, 42 and, I have provided means for this to occur without transmitting any -appre-- ciable shock to the switch or is being operated.

The side bars 40, 40, which carry the magnet with its core are pivoted at their lower ends to the post members 31', 31 and the upper ends of the bars 40, 40 are free to swing between the stop lugs 42, 42 and the back plate 35. Normally the upper ends .of the side bars 40; 40 rest against the stop lugs 42, 42 but in case of an excessive impact of thearmature in striking against the core of the magnet the magnet part of the unit is free to swing back towards the base plate and thus absorb the excessive momentum of the armature.

In some cases the core of the magnet may remain in this receded position due to the frictional resistance in which event the spring 23 will exert more pressure against the movable contacts to hold them more rigidly in the On position but, while this is desirable, it is not necessary since the construction is designed so that while normally, the, core portion of the magnet may recede slightly. in response to the other device which impact of the armature, it will return to its posi-.

tion with the upper ends of the side resting against the stop lugs 42, 42.

When the electro-magnetic circuit is deenergized either intentially or automatically, the armature is of course released and swings or falls away from the core by gravity and its weight tends topullthe links 50 and attached members outwardly. The lost motion connection of the pin Si in the slots 53 allows the bars 40, 40

- armature to have a certain freedom of -movement so that when it isreleased and starts to move it is substantially free of the link 50 and attached parts and thus is able to obtain considerable momentum without the resistance of the other parts and before it hasstarted to move .thecontacts to the open circuit or Off position.

By this construction a hammer-like blow is given to the cross bar 22 in the opening movement of the switch which prevents the contacts or other parts from sticking. The loose pivoting of the armature" in its carrier frame permits it to adjust itself to the core of the magnet and thus overcome any difllculty due to irregularities in mechanical construction and at the same time ensures the maximum strength of the magnetic field. Also, by means of the lost-motion connection between the armature and the connecting link 50, the armature does not start the movement of the switch contacts until pin 5| reaches the other end of the slot 53 in the link 50 and by this time the armature has attained sumcient speed of movement to cause a very quick-make action of the movable switch contacts.

I claim:

1. An electro-magnetic switch actuator including a supporting frame, anelectro-magnetic core hinged at its lower end to said frame and having its weight so disposed as to swing outwardly at its upper end away from said frame, an armature hinged at its lower end to said frame and movable independently of the core, means for limiting the forward tilting movement of the core and means for limiting the forward tilting movement of the armature, said core being tiltable toward the rear with the armature so as by its inertia at least partially to absorb momentum of the armature toward the core, the pivotal centers of said magnetic core and of said armature being spaced apart for the purpose specified.

2. An electro-magnetic switch actuator including a channel-like supporting frame, an electromagnetic core hinged at its lower end inside of said frame and having its weight so disposed as to hang outwardly at. its upper end away from said frame, an armature hinged at its lower end to said frame and movable independently of and also with the core, means for limiting the forward tilting movement of the core and means for limiting the forward tilting movement of the armature, said core being tiltable toward the rear with the armature, the armature and the magnet core being movable together rearwardly when the magnet is energized and the armature strikes ters so that the core of the magnet will yieldingly check the operating impact of said armature and the magnetic grip of said armature and said magnet will check further axial movement of said armature.

4. An electro-magnet including a magnet core and coil, an armature pivotally supported atits lowe'rend and adapted to coact with said core, a stop for limiting the movement of the core toward the armature, the armature being free to move toward the core, a pivotal support for the magnet core spaced apart; from the pivotal axis of the armature so that the'core of the magnet will check the momentum oi the armature and the magnetic force between the magnet and the armature produces friction suflicient to retard the action of the armature with respect to the'core. 5. A switch actuating electro-magnet constplction comprising a core having an energizing coil and pivoted at its lower end near the rear so that ing a core and a coil hinged at its lower end with its center of gravity disposed in front of the hinged center, a stop normally limiting the forward swinging movement of the core and coil, an armature coacting with the core and hinged on an axis spaced apart from the hinged axis of the core and means to be actuated by the movement of the armature and having a lost motion connection therewith.

BENJAMIN E. GETCHELL.

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