US1959868A - Switching mechanism - Google Patents

Description

May 22, 1934. D. c LARSON SWITCHING MECHANISM Filed June 30 1932 2 Sheets-Sheet l FIGI.

5b 78 74 FIGS M CM LM INVENTOR ATTORNEY Y May 22, 1934. D. c. LARSON SWITCHING MECHANISM Filed June 30', 1932 2 Sheets-Sheet 2 FIGS? 3W C2! Lea/um INVENTOR ATTORNEY will Patented May 22, 1934 UNITED STATES SWITCHING MECHANISM David Carl Larson, Yonkers, N. Y., assignor to Otis Elevator Company, New York, N. Y., a corporation of New Jersey Application June 30, 1932, Serial No. 620,169

13 Claims.

The invention relates to electromagnetic switches and especially to electromagnetic latching switches for use in elevator control and signal systems.

In elevator installations in which signalling systems such as annunciators or systems for controlling the lighting of hall lanterns are provided and those in which the slowing down of the car is controlled by intending passengers at the landings, the operation desired may be had through the utilization of one or more electromagnetic latching switches for each floor served by the car. Such switch usually comprises an electromagnet coil energizable to move the switch contacts to engaged condition, a latch for maintaining the contacts engaged after deenergization of the operating coil and a restoring coil energizable to release the latch to permit the separation of the switch contacts. Particularly in present day high building constructions, the number of these switches required for such systems makes the cost of the switches and the total space occupied by them an important factor.

The principal object of the invention is to provide an electromagnetic latching switch which is of compact construction and which may be cheaply manufactured and installed.

One feature of the invention resides in the provision of an electromagnetic latching switch in which the operating coil and the restoring coil occupy a minimum of space.

Another feature of the invention lies in the provision of a hinge for the contact lever of a switch which has the advantages of both the knife edge and hinge pin constructions.

A third feature resides in the arrangement of the terminals for the switch to facilitate the connecting of like terminals of two or more of the switches in parallel.

Another feature resides in the mounting of the switches as units on cross bars of a framework to provide a switchboard containing any desired number of switches.

Another feature lies in the provision of fiat spring contact members and protecting means for preventing such members from being displaced from their normal position beyond a certain amount.

Other features and advantages of the inven-- tion will become apparent from the following description and appended claims.

In carrying out the invention, the operating coil of the switch is arranged to extend outwardly from the switch base with the restoring coil immediately beneath the operating coil and at right angles thereto. The operating coil is of a length greater than its diameter while the restoring coil is of a diameter greater than its length. By this arrangement, the overall space taken up by the coils in a plane parallel to the base of the switch is minimized.

The hinge for the contact lever is constructed of four plates in the form of punchings. These plates are arranged in pairs with the pairs at an obtuse angle. The plates of each pair are secured together with those of one pair arranged to form spaced apertures into which prongs formed on one of the plates of the other pair extend. An aperture is formed in the other plate of the other pair into which a prong on one of the plates of the first pair extends. This provides a rocker construction in which any relative movement of the pairs of plates other than a pivotal one is obviated.

Different terminal studs of the switch extend different distances from the base of the switch. This facilitates connecting like terminals of the switches in parallel when the switches are mounted in a group inasmuch as like terminals of the switches extend the same distances from the switch bases but a different distance from the bases than other like terminals, thus permitting the ready connection of like terminals by jumpers without interference.

Each switch is provided with a clamp at each end for securing it on a pair of spaced bars suitably supported in a frame. Any number of these switches may be mounted in this manner to form a switch panel without the use of slates or other insulating panels, thus providing a simple and economical structure.

Each movable contact is a fiat leaf of spring material mounted on the contact lever. This lever is provided with a guard for the contacting end of each leaf to prevent the leaf being stressed beyond its elastic limit.

In the drawings:

Figure l is a side elevation of an embodiment of the switch, illustrating the switch in unlatched condition;

Figure 2 is a front elevation of the same;

Figure 3 is a rear elevation of the same;

Figure 4 is a section taken along line 4-4 of Figure 3, but illustrating the switch in latched condition;

Figure 5 is a view taken along line 55 of Figure 1, illustrating the switch in unlatched condition;

Figure 6 is a fragmental detail taken along line 6-6 of Figure 1;

Figure '7 is a fragmental detail of the hinge construction;

Figure 8 is a section taken along line 88 of Figure 7; and

Figure 9 is a schematic representation of the arrangement of a plurality of the switches in a group and illustrating the manner in which like terminals of the switches may be interconnected.

Referring to the drawings, the switch is ilcarried by a contact lever 36 of insulating malustrated as'provided with three pairs of making contacts. The stationary ones of these contacts are mounted on a base 21 moulded of insulating material. Each of these stationary contacts, which have been designated 22, comprises an elongated contact stud 23 having a tungsten tipped contact point 24 secured in a hol drilled in the outer end of the stud. The other end 25 of each contact stud is threaded for the purpose of securing it to a terminal stud moulded into and extending through base 21. The terminal studs for these contacts are designated 26, 27 and 28 and each is provided with a threaded aperture to receive a contact stud.

The movable ones of the switch contacts are terial pivotally mounted on the frame 31 of the switch, this frame being secured to the base 21. Each of these movable contacts, which have been designated 32, comprises a leaf spring 33 having a tungsten tipped contact point 34 secured in a hole drilled in the contacting end of the spring. The lower end of eachspring is arranged in a slot 35 provided in lever where it is secured by a screw 36 and binding nut 37. The bottom of each of the slots slopesinwardly, as shown in 1 Figure 4. The springs are held against the bottom of their respective slots by clamps 38. Each of these clamps is provided with a hole through which the screw 36 extends and its top portion 40 is bent over at right angles so as to press against the spring when the nut is tightened to secure the spring in place.

It is preferred to make the contact. springs of phosphor-bronze. The upper end of each spring extends through a square shaped aperture 41 in 'a guard 42 formed on the end of the contact lever. This arrangement protects the contact springs by preventing their being moved into positions where their elastic limit is exceeded. 7

The frame 31 comprises a bracket 43 formed ,With a hinge plate 44 which extends outwardly from the base. A second hinge plate 45 is arranged on top of hinge plate 44. These hinge plates are secured together by a screw 46 as'will be explained later. Plate 45 is maintained in definite position with respect to plate 44 by doweling plate 45 into plate 44 as indicated at 47 and 48. The dowels on plate 45 and receiving apertures on plate 44 may be formed by punching. Hinge plate 44 is formed with a transversely extending slot 56 near its outer end. The middle portion of the outer end of plate 44 is also cut away, leaving prongs 51 and 52. The end of hinge plate 45 is cut away at the sides back to the rear edge of slot 50, so as to cover only the portion of slot 50 up to the prongs 51 and 52, thus forming holes 53 and 54. A prong 55 formed on the end of plate 45 extends outwardly therefrom between prongs 51 and 52. A pair of plates 56 and 57 is secured to contact lever 30 by screws 58. Lugs 66 are formed on the contact lever and extend into recesses provided in these plates to definitely locate the plates with respect to the lever. In addition, plate 57 is doweled into plate 56 at 61 and 62. Plate 56 is formed with prongs 63 and 64 which extend into the holes 53 and 54 formed by plates 44 and 45. Plate'57 is provided with an aperture 65 into which prong 55 extends. I'he above described arrangement of plates 44, 45, 56 and 57 forms a hinge, thus providing a pivotal support for the contact lever.

The plates 56 and 57 form an armature for an electromagnet 66 mounted on and. extending outwardly from frame 31. This electromagnet, upon energization, acts through the armature to move the contact lever 30 to contact making position. The electromagnet comprises a coil 67 arranged on a core 68. This core comprises a plurality of laminations 70 secured between side plates 71 as by rivets 72. At the inner end of the core, a fastening link 73 is pivoted between side plates 71. This link is provided with a threaded aperture 74 into which a screw 75 extends from the rear of base 21 to mount the electromagnet. Horns 76 formed by the side plates at the outer end of the core retain the coil on the core.

The bracket 43, in addition to its horizontally extending hinge plate 44, comprises a plate 77 which extends upwardly behind cofl 67 and forms a part of frame 31 Behind plate 77 is a base plate 78. Plate 77 is doweled into plate 78 at 80 and plate 78 is doweled into base 21 at 81 and 82. These plates are secured to the base by screw 75, a slot 83 being formed in the plates through which side plates 71 and link 73 extend. The laminations 70, being wider than the side plates 71 form shoulders which abut against plate 77 as screw 75 is tightened to secure the plates in position. A recess 84 is formed in base 23. to receive the end of core 68.

After the movable contacts havebeen moved into engagement with the stationary contacts, they are latched in engaged position by the cooperation of the latch portion formed on the bottom of the contact lever and a plate 85 hinged to the bottom of plate 78. The latching portion of contact lever 30 comprises a notch 86 formed'by a lip 87 extending inwardly from the bottom of the lever. When the armature of the magnet 66 is moved to its attracted position, themovable contacts are moved into engagement' with the stationary contacts before the armature is brought to a stop. Continued movement of the armature after contact engagement is effected results in the movable contacts rubbing across the stationary contacts, thereby insuring positive contact engagement. Movement of the armature'is stopped, by the engagement of lugs 60 with horns 76, these lugs extending beyond the armature to prevent the armature engaging the core. The contact springs 33 yield after the engagement of the contacts takes place, the apertures in guard 42 being of suficient size to permit the described operation to take place. Just before the armature is brought to a stop, a point is reached where the 7 in the enlarged portion into which plate 78 extends. The rear end of plate 85 is cut away into the slot to form prongs 96. these prongs extending into recesses 91 formed in base 21.

The hinge for contact lever 30 is at such point that the weight of the lever and parts mounted thereon biases it to its position in "which the contacts are separated. To release'the contact lever and permit the separation of the contacts,

plate 85 is moved upwardly out of notch 86 by an electromagnet 92, the plate forming an armature for the electromagnet. The electromagnet is secured to bracket 43 by screw 46. It comprises a coil 93 arranged on a core which extends downwardly from hinge plate 44. This core is movement of thecontact lever.

screw 46 and the bushing to retain the coil on thecore. The tightening of screw 46 in the assembly' operation clamps the bushing 94 against the bottom of plate 44, thus locking plates 44 and 45together. At the same time coil 93 is secured to bracket 43, this arrangement placingrtherestoring coil immediately beneath the operatingrcoiland-at right angles thereto. An aperture 97 isprovided in armature to receive the head. of screw 46 when the armature is' attracted. With this construction, plates 44 and"45.:form part of the magnetic circuit for both'the electromagnets 66 and 92.

Upon'energization of electromagnet 92, armature-:85 is moved to attracted position where it isbrought to a stop" by its engagement with washers 99. As. the upward movement of the armature takes place, its outer end moves out of:notch.86. This releases contact lever 30 which is=thereuponreturned to contact separated condition. by theaction of gravity, aided initially by. the contact springs. A slot 98 is provided in the contact lever to admit the end of armature 852as-2the return movement of the contact lever takes-place. The return movement of the lever isbrought to a stop by the engagement of the end 'ofiarmature 85 .withthe bottom of slot 98.

A plurality of additional terminal studs 100, 101, 102, 103 104 and 105 are moulded into base 21. These studs extend only partially into the base 'and constitute terminals for the leads from the magnet coils 6'7 and 93 and for the movable contacts. 32. The movable contacts are connected'to their respective terminals by flexible conductors, the conductor, designated 106, for oneof the 'outermovable contacts being illustratedin Figure 1. This conductor is suitably insulated, as by a protective covering of carnbrie: tubing, and is provided at each end with suitableclips for effecting the connection. From the movable contact, theconductor is led around to the back of lever 30-where it extends upwardly -th-rough a-slot107 provided in the lever and in which it is held by a clamp 108 securedby screw 36-. From this point, the conductor leads .to-aznotch- 110 formed in the side of the base 21.

Fromithe notch it extends to the terminal stud where it: is secured by suitable binding nuts. Suflicient bight is provided in the conductor between notch' 110 and slot 107 to allow for pivotal The conductor forzthe: other outer movable contact is arranged in: a. similar manner. The conductor for middle movable contact is also arranged in a similar-manner and is led through the same slot in lever30 as the conductor for one of the outer movable contacts.

The conductors from the magnet coils are led to theirterminal studs through wider notches 111 along the sides'of base 21. In elevator installations'in which the switch would be useful for sigsembled: Plates- 44'and 45 are secured together and electromagnet 92 secured thereto by screw 46. Plate 85 is slid over plate 78 and plates 77 and 78 and electromagnet 66 are secured to base 21 by screw '75. Plates 56 and 57 are secured in hinged relation to plates 44 and'45 and to the contact lever by screws 58. This not only pro? vides' a construction which may be economically assembled but also one which may be readily and easily taken apart whenever desired.

During movement of contact lever 30, the outer edge of the bottom of plate 56 to the sides of the prongs 63 and 64 rocks on plate 44, thus forming.

a knife edge fulcrum for the lever. The arrange ment of prongs and apertures provided by plates 44, 45, 56 and 57 prevents any movement of the lever except a pivotal one. Thus akniie edge hinge construction is provided which requires very little clearance, has little friction and re? quires no lubrication, and at the same time has all the advantages of the hinge pin construction. In addition, this hinge arrangement is very economical to manufacture as the plates may all be formed from punchings.

The coils 67 and 93 are wound with the proper amount of wire to effect the desired operation of their respective armatures. By making coil 67 of a length greater than its diameter and coil 93. of a diameter greater than its length, a construction is provided in which the coils occupy a.

minimum overall space in a plane parallel to the base of the switch. It has been found that a suitable construction is obtained by making the diameter of the restoring coil 93 substantially equal to or slightly greater than the diameter of the operating coil 67 and not to exceed the length of the operating coil.

The economy of space thus obtained is particularly important where a large number of switches are mounted in a group. The space taken up by the switches in a control room is an important factor as may be seen from an eighty floor elevator installation, for example, where both an up switch and a down switch is provided for each intermediate floor.

The construction of the switch also admits of mounting the switches side by side on cross bars, thus not only further economizing on space but also eliminating the expense of a slate panel. The mounting of a group of nine switches is illustrated schematically in Figure 9 by way of example. The crcss bars, designated 112, extend horizontally between uprights (not shown). The switches are arranged between the cross bars and in abutting relation at their sides. noted that this closes the notches 110 and 111 for the leads from the switch parts to the terminals, thus definitely locating the wires. In this connection, it is preferred to arrange notches 110 at different points on the two sides of the base of each switch, thus causing these notches to be covered by the side of the base of the adjacent switch.

The manner of securing a switch to the cross bars is illustrated in Figures 1, 3 and 4. The

- switch is clamped to the bars at both the top and It is to be provides convenient access to the switch terminals.

Where these switches are employed as floor relays in an elevator system, as, for example, to control signalling operations or to control the slowing down and stopping of the elevator car, certain'like terminals of each switch are connected in parallel relation. Such connections are facilitated by extending different terminal studs of each switch different distances from the base 21. A suitable arrangement for this purpose is illustrated in which terminal stud 28 extends outwardly from the base a certain distance, terminal stud 26 extends outwardly from the base a greater distance, and terminal stud 2'7 extends outwardly from the base a distance intermediate the distances which terminals 26 and 28. extend from the base. Terminals 103, 104 and 105 are simi- 'larly extended different distances from the base but oppositely in that terminal 103 extends outwardly the same distance as terminal 28, terminal 104 the same distance as terminal 27 and terminal 105 the same'distance as terminal 26. Terminals 100 and 102 extend outwardly the same distance as terminal 2'7, thus providing a similar relationship between terminals 105, 102 and 28, and between terminals 103, 100 and 26; Terminal 101 extends outwardly from the base a greater distance than terminals 100 and 102. Like terminals of each of the other switches are extended outwardly the same distances from their bases. This permits the desired parallel connections to be effected by jumpers without interference with other jumpers or connectors.

Suitable jumpers for connecting like terminals of the switches are illustrated in Figure 9. The jumpers designated 11'? are for efiecting the desired parallel connection of like terminals of adjacent switches in the same horizontal row and extend horizontally between these terminals, as

illustrated. 'Each of these jumpers comprises two connecting portions 118 which extend Vertically from the studs and which are joined by the web portion 120. These jumpers may be suitably formed by punching them from sheet copper. With like terminal studs or" the switches extending outwardly from their bases the same distance and with this distance different from V thatwhich other like terminal studs extend from the bases, the jumpers which connect different like terminals are in different planes, as may be seen in Figure 6. Thus, a convenient arrangement is provided for interconnecting like terminals of a group of switches without interference.! A jumper 121 has been shown connecting like terminals of the switches in an outer column in vertical alignment. This jumper is of the same construction as jumpers 117 with the exception that the web portion is longer to suit the greater distance between the terminals. The vertically extending jumpers are particularly useful for connecting like terminals of a group of switches to the like terminal of one of the outside switches which acts as a feed terminal, the like terminals in each horizontal row being connected as illustrated for two switches in the bottom row so as to be fed by the vertical jumpers.

Although the invention has been described as applied to a latching switch, certain features of the invention are applicable. to other types of switches.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof,

it is intended that all matter contained in the above description or shown in the. accompanying drawings shall be interpreted as illustrativeand not in a limiting sense.

What is claimed is:

1. Switching mechanism comprising; a base; a stationary contact secured to said base; a movable contact for engaging said stationary contact; a lever carrying said movable contact, said lever being biased to contact disengaged posi tion; a support extending outwardly from said base at right angles thereto; an armature seemed to said lever and pivotally secured to said sup port to form a fulcrum for said lever; an elec tromagnet for attracting said armature to move the lever into contact engaging position, said electromagnet having a core extending outwardly from said base at right angles thereto and a coil on said core, said coil having a length greater than its diameter; a latch member pivotally mounted on said base and cooperating with said contact carrying lever, upon attraction of said. armature by said electromagnet, to latch said contact carrying lever in contact engaged position; and a restoring electromagnet arranged be low said operating electromagnet and at right angles thereto, said restoring electromagnet hav-.' ing a core secured to said support and a coil on said core, said coil having a diameter greater than its length, substantially equal to the diam- 1 eter of the coil of the operating electromagnet and less than the length thereof, and said restoring electromagnet upon energization acting to attract said latch member to release said contact carrying lever to permit its return to contact 1 disengaged position, said contact carrying lever, upon returning to contact disengaged position, being brought to a stop by engaging said latch member.

2. Switching mechanism comprising; a station-' ary contact; a contact spring for cooperating with said stationary contact; an electromagnet;

an armature for said electromagnet for moving said contact spring with respect to said stationary contact upon being attracted by said electromage net; and guarding means for said contact spring to prevent its being stressed beyond its elastic limit. l

3. Switching mechanism comprising; an elec tromagnet; an armature for said electromagnet; a stationary contact; a leaf contact spring for cooperating with said stationary contact; and apivoted member carrying said. contact spring, said member being secured to said armature so as to effect movement of said contact spring with l .1

ver of insulating material carrying said contact spring, said member being secured to said armature so as to effect engagement of the end of said contact spring with said stationary contact upon attraction of said armature by said electromagnet and being provided with, an aperture at the 1 contacting end of said spring through which the W spring extends so as to prevent movement of the spring into position where its elastic limit is exceeded.

5. An electromagnetic latching switch compris ing; a vertically disposed base; an operating magnet having a coil of a length greater than its diameter mounted on said base so that its core extends outwardly therefrom at right angles thereto; a frame of magnetic material mounted on said base so that the body of said frame is parallel to and below said magnet and constitutes the return path for the flux of said operating magnet; an armature for said operating magnet pivotally supported at the outer end of said frame; an operating lever secured to said armature and having a portion extending downwardly below the body portion of said frame; switch means "actuated by said operating lever; a latch member pivotally supported adjacent said base below the body portion of said frame with the outer end of said latch member engaging the downward extension of said operating lever in the position thereof resulting from 'energization of said operating magnet to maintain said operating lever in such position, said latch member being formed of magnetic material from its pivot at least to its mid-length; a member of magnetic material positioned adjacent said base so as to I provide a flux path from the pivot of said latch member to the body portion of said frame; and a reset magnet having a coil of a diameter greater than its length mounted on the body portion of said frame at right angles thereto with the core of said reset magnet extending downwardly so the other to provide an aperture; and a support for said armature forming part of the magnetic circuit for said electromagnet, said support comprising a second pair of superimposed plates, at least one of which is of magnetic material, said plates being formed to provide spaced apertures to receive said prongs on said one armature plate and a prong to extend into the aperture on the other armature plate, thereby providing a hinge for said armature.

7. An electromagnetic switch comprising; a

base; an electromagnet secured to said base so that its axis of its core end is horizontal; and an armature, armature support and armature hinge comprising four plates of magnetic material arranged in pairs with their fiat sides in contact, one pair forming said armature and the other pair being secured to said base and extending horizontally to form a support for said armature and a return path for the flux from said electromagnet, the supporting pair of plates being formed to provide spaced apertures and a prong at the outer end between the sides thereof and the armature pair of plates being formed to provide prongs which extend into said spaced apertures and an aperture to receive said first named prong.

8. An electromagnetic switch comprising; a vertical base; an electromagnet secured to said base and extending horizontally therefrom; a pair of plates, at least one of which is of magnetic material, arranged with their fiat sides in contact and secured to said base and extending horizontally therefrom, the flat sides of said plates being in horizontal planes and forming part of the magnetic circuit for said electromagnet, the

lower plate being recessed inwardly from its outer end and formed with notches extending toward the sides of the plate at the inner end of said recess, the upper plate being formed with a prong on its outer end intermediate its sides and extending outwardly to the end of the bottom plate; and an armature for said electromagnet comprising a pair of plates, at least one of which is of magnetic material, with their flat sides in contact, the inner one of said armature plates being formed with prongs which extend into said notches, the bottom of said inner plate to the outside of each of its prongs resting on the bottom plate of said first named pair to form a fulcrum, and the outer one of said armature plates being formed with an aperture to receive said prong on the upper plate of said first named pair.

9. An electromagnetic switch comprising; a vertical base; an electromagnet secured to said base and extending horizontally therefrom; a pair of plates of magnetic material with their fiat sides in contact secured to said base and extending horizontally therefrom, the fiat sides of said plates being in horizontal planes and forming part of the magnetic circuit for said electromagnet, the lower plate being recessed inwardly from its outer end and formed with notches extending toward the sides of the plate at the inner end of said recess to form prongs, the upper plate covering said recess between said prongs and out to the inner edges of said prongs, thus forming spaced apertures, and being formed with a prong extending outwardly between the first named prongs; and an armature for said electromagnet for movement through a small range of angles all obtuse to said pair of plates, said armature comprising a pair of plates of magnetic material with their fiat sides in contact, the inner one of said armature plates being formed with prongs which extend into said spaced apertures, the bottom of said inner plate to the outside of each of its prongs resting on the bottom plate of said first named pair to form a fulcrum' and being recessed between its prongs to clear the upper plate of said first named pair, and the outer one of said armature plates extending at its bottom between said prongs of the bottom plate of said first named pair and being formed with an aperture to receive said prong on the upper plate of said first named pair, thereby preventing any substantial movement of said pair of armature plates relative to said first named pair of plates except a pivotal one through said range of angles.

10. An electromagnetic switch comprising; a magnet having a free core end; an armature for said magnet for pivotal movement toward and away from said free core end about a horizontal axis below the same, said armature at the pivot end thereof being formed with two portions on opposite sides of a common plane passing through said horizontal axis but displaced from each other along said axis, the inner one of said armature portions terminating at said horizontal axis and the outer one of said armature portions extending beyond said horizontal axis; and a support for the pivot end of said armature comprising a member of magnetic material forming part of the magnetic circuit for said magnet and mounted below said free core end so that said horizontal axis is included in said support, said member being formed with two portions on opposite sides of a common plane passing through said horizontal axis but displaced from each other along said axis, the upper one of said support portions terminating at said horizontal axis against said outer armature portion and the lower one of said support portions extending under and engaging said inner armature portion, whereby pivotal movement of said armature toward and away from said free core end through angles obtuse to said common plane of said support portions is effected by the rocking of the bottom outer edge of said inner armature portion on said lower support portion and by the rocking of said outer armature portion about the lower terminal edge of said upper support portion, both said edges lying in said horizontal axis.

11. An electromagnetic switch comprising; a magnet having a free core end; an armature for said magnet for pivotal movement toward and away from said free core end about a horizontal axis below the same, said armature at the pivot end thereof being formed with two portions on opposite sides of a common plane passing through said horizontal axis but displaced from each other along said axis, one of said armature portions being in two parts, one part on either side of the other armature portion, the inner one of said armature portions terminating at said horizontal axis and the outer one of said armature portions extending beyond said horizontal axis; and a support for the pivot end of said armature comprising a member of magnetic material forming part of the magnetic circuit for said magnet and mounted below said free core end so that said horizontal axis is included in said support, said member being formed with two portions on opposite sides of a common plane passing through said horizontal axis but displaced irom each other along said axis, one of said support portions being in two parts, one part on either side of the other support portion, the number of parts in the lower one of said support portions corresponding to the number of parts in said outer armature portion, the upper one of said support/portions terminating at said horizontal axis against said outer armature portion and the lower one of said support portions extending under and engaging'said inner armature portion, whereby pivotal movement of said armature toward and away from said free core end through angles obtuse to said common plane of said support portions is efiected by the rocking of the'bottom outer edge of said inner armature portion on said lower support portion 7 and by the rocking of the said outer armature portion about the lower terminal edge of said upper support portion, bothsaid edges lying in said horizontal axis.

12. An electromagnetic switch comprising; a magnet having a horizontal core end; a pair of stationary plates of sheet material secured together with their flat faces in contact, and arranged horizontally below and spaced from said core end, at least one of said stationary plates being of magnetically responsive material and forming part of the magnetic circuit of said magnet, the outer end of the upper stationary plate being cut off transversely to form a straight edge of one or more sections and being cut away at one or more places to expose'portions of the outer end of the lower stationary plate in alignment with said edge, the outer end of said pair .of stationary plates being cut to provide one or more apertures therethrough, with the outer edge or edges of such apertures substantially in alignment with said first named edge; an armature for attraction by said coreend comprising two plates of sheet material secured together with their flat faces in contact, at least one of said plates being of magnetically responsive material, the pivot end of the inner plate of said armature plates being cut away to clear the portion or. pore tions of said upperstationary plate terminating in said first named edge, so that said first named edge abuts against the inner surface of the outer plate of said armature plates, the pivot end of.

the inner plate of said armature plates also be-: ing cut off transversely to form a'straightedge' of one or more sections each of which 'abuts,

against an exposed portion of said lower stationary plate and being formed with one or more prongs each extending into a corresponding one of said apertures in said pair of stationary plates;

and means confining the motion of said armature to a relatively small range of angles all obtuse to said stationary plates so that the weight of said armature is supported by the outer corner of said second named straight edge rocking on the exposed portion or portions of said lower stationary plate, and so that the pressure of said armature due to the attraction of said core end for said armature when said magnet is energized, is transmitted through the lower corner of said first named straight edge about which'rocks said outer armature plate. 7

13. An electromagnetic switch comprising; a magnet having a horizontal core end; a pair of stationary plates of sheet material secured together with their fiat faces in contact and arranged horizontally in vertical alignment with said core end, at least one of said stationary plates being of magnetically responsive material and forming part of the magnetic circuit of said magnet, the outer end of the stationary plate nearersaid core end being cut oii transversely to form a straight edge of one or more sections, being out to form at least one prong extending beyond said straight edge and being cut away at one or more places to expose portions of the outer end'of the-other stationary plate in alignment with said edge, the outer end of said pair of stationary plates beingcut to provide one or more apertures therethrough, with the outer edge 'or edges of such apertures substantially in alignment with said first named edge; and an armaturefor attraction by said core end comprising two. plates of sheet material secured together with;

their fiat faces in contact, at least one of said plates being of magnetically responsive material, the pivot end of the inner plate of said armature plates being cut away to clear the portion or portions of said stationary plate terminating in said first named edge and said first named prong, the pivot end of the outer plate of said armature plates being formed with an aperture receiving said first named prong so that said first named edge abuts against the inner surface or" the outer plate of said armature plates, the

pivot end of the inner plate of said armature plates also being out off transversely to form a straight edge of one or more sections each of which abuts against an exposed portion of said second named stationary plate and being formed with one or more prongs each extending into a corresponding one of said apertures in said pair of stationary plates, said four plates thereby providing a portion of the magnetic circuit for 7 DAVID CARL LARSON.

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