US2671835A

US2671835A - Automatic switch

Info

Publication number: US2671835A
Application number: US234211A
Authority: US
Inventors: Leyhausen Wilhelm
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-06-29
Filing date: 1951-06-29
Publication date: 1954-03-09
Anticipated expiration: 1971-03-09

Description

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AUTOMATIC SWITCH Filed June 29, 1951 7 SheetsSheet '7 fiwezzivr: fif. L 6320x4 06 612/ Patented Mar. 9, 1954 UNITED STATES PATENT OFFICE 2,671,835 AUTOMATIC SWITCH Wilhelm Leyhausen, Nurnberg, Germany Application June 29, 1951, Serial No. 234,211

20 Claims.

The present invention relates to an automatic switch.

Automatic switches due to their characteristics and advantages are presently being employed on a heavily increasing scale in distribution boards and meter boards as substitutions for fuses.

The present developmental trend in construction of such switches is towards a reduction of space and size factors in order to reduce the size of switches down to that comparable with normal safety fuses. If space and size factors can be reduced to a minimum the advantage is obtained that the dimensions of the distribution board may be reduced and constant or fixed di mcnsions thereof can be established so that with the minimum size of safety switches maximum circuits may be embodied with distribution or meter boards of these fixed dimensions.

It is necessary however to bear in mind that the reduction in size of automatic switches must i be kept within certain limits since the electric switching-off effect must not be reduced by unduly reducing the size of the switch and by reference to the size of switches is meant not only the size of the moving parts but also the casing or base size and therefore in order to comply with these limitations the present invention has for one object to provide automatic switches in which the unused space of the total switch structure is reduced to a minimum. It is a further object to provide an automatic switch which includes a thermic cut-out for overload and an automatic cut-out for sudden "overload or short circuit and in connection with such switches it has been found that it is possible toattain a complete utilization of space with consequent reduction in size if the mechanical switch mechanism is "separated from the'switch components subjected to electrical stress. More particularly 'the switch contacts the magnetic coil and the means for thermic release, for example a bimetallic strip.

It is therefore an additional object to provide a switch structure of the aforementioned type in which the mechanical switch mechanism and the components subjected to electrical stress are arranged in separate housings. It is a specific object to provide such an arrangement in which the housing parts are arranged in superimposition.

It is a further object to provide such a switch structure of generally rectangular cross section.

additional object is to provide a specific housing structure for the switch components including U -shaped frames arranged in opposite relation with 'the 'bightsor connecting portions 2 in juxtaposition thereby providing for ease of assembly.

Consistent with maximum utilization of space in construction of automatic switches of the type referred to, it is an object of this invention to provide improvements in the structural details of such switches including the details of the housing construction and it is also an object to provide a switch structure in which the coil of the magnetic cut-out is mounted beneath a three part knee joint linkage embodied with the mechanical switch components and to structurally dispose the armature of the magnetic cut-out to cooperate with this linkage to provide for sudden disengagement of the switch contacts.

it is an additional object to provide a switch structure in which the housing-components for those parts of the switch subjected to electrical stress is divided lengthwise into three spaces or chambers, one constituting the contact chamber, the second receiving the magnetic coil and the third the .disengagingelements, that is the armature and the bimetallic member.

It .is believed obvious that all types of automatic switches can not be constructed with the same space requirements. In other words, all switches can not be reduced to the same small size such as switches for high current loads, those of the type which embody two magnetic coils, automatic switches with a zero cut-out and those which also embody signal contacts. The dimensions of these latter switches can not be reduced to a degree such that their size will correspond with the size or" automatic switches utilized with normal low current values. The latter type switch can have its exterior dimension reduced to a substantially fixed ratio but the more complex switches generally can not conform to the same space requirements. However, the present invention by standardization of the housing components as regards type and manner of assembly provides for ease of production of automatic switches of all types in that the same heighth factors are present in simple and complex switches with the more simple switches for normal low current values having housing dimensions at the most only half the width of housing dimensions for switches having higher current values. Thus, it is the object of this invention to standardize automatic switch structure which the space factors of a distribution or motor board are utilized at a maximum degree in that two normal low current value switches occupy the same space as one complex switch therefore providing for easy substitution and rearrangement of switches on distribution and meter boards which thus can be standardized as to size and contact arrangements.

Further and more specific objects will be apparent from the accompanying drawings which illustrate two preferred forms of the invention of which Figures 1 to 25 illustrate one embodiment and Figures 26 and 2'7 illustrate a second embodiment both embodiments being considered as types of switches for normal current values with narrow housings.

In the drawings:

Figure 1 illustrates the first embodiment in vertical section;

Figure 2 is a section on line 11-11 of Figure 1;

Figure 3 is a section on line IIIIII of Figure 1;

Figure 4 is a view of a partial detail of Figure 2;

Figure 5 is a view taken along lines V-V of Figure 1, that is with the top of the casing removed;

Figure 6 is a view along lines VIVI Figure 2 with the outer switch casing removed;

Figure 7 is a section along lines VIIVII of Figure 6;

Figure 8 is a bottom plan view of the base of the automatic switch of this embodiment;

Figure 9 is a rear elevation of the embodiment with the rear lower U-shaped leg and the closing wall of the contact chamber removed;

Figure 10 is a top plan view of the switch base taken along line X-X of Figure 9;

Figures 11, ,12 and 13 illustrate the switch lever in side, top and end elevation, respectively;

Figures 14, 15 and 16 illustrate the hammer lever of the thermic release in side, top and end elevation, respectively;

Figures 1'7, 18 and 19 illustrate the locking pawl for the thermic release in side, end and top elevation respectively;

Figures 20 and 21 illustrate the magnetic armature and its release lever in plan and end elevation respectively;

Figure 22 illustrates the knee joint linkage including the switch handle;

Figure 23 is a top plan view of a portion of Figure 22; and

Figure 24 is a section taken along line XXIV- XXIV of Figure 22;

Figure 25 is a view corresponding to Figure 6 showing the switch in closing position;

Figures 26 and 27 illustrate a further embodiment of the invention with Figure 27 denoting a .view taken along lines XXVIIXXVII of Figure 26;

Figure 28 is a view of a modified form of magnet coil structure utilized with the first embodiment; and

Figure 29 illustrates an arrangement of automatic switches of different widths on a distribution or meter board.

With respect to the first embodiment of the invention as illustrated in Figures 1 to 25 the switch includes a U-shaped frame 2 mounted on a base I and which frame houses the switch components subjected to electric stress. The switch chamber 3 embodies therein two

fixed contacts

4 and 5 shown more clearly in Figure 9, a movable contact bridge 6, a magnetic coil 1 and its associated armature 8 and a bimetallic element 9 providing for thermic disengagement of the contacts when the current exceeds a predetermined value. The U-shaped frame 2 as shown in Figures 2 and 3 includes a front leg III, a rear leg I I and an upper bight or face por- 4 tion I2 on which rests the face portion I3 of a reversely disposed U-shaped frame including a front leg I4 and a rear leg I5. All of the parts confined within the respective U-frarnes are covered by a housing I6. The parts or components mounted in these U-frames occupy substantially the same bottom or cross sectional area as the base member which includes a marginal flange or shoulder I'I upon which the housing I6 is mounted. The base is substantially hollow, opening downwardly and provided on its under side with a current conducting strip or rod I8 to which is fastened by means of a screw I69, Figure 1, a contact strip I9 which extends through a lateral reces provided in the base. The contact strip I9 carries a contact terminal 2I having a threaded bore 22 so that a contact screw may be attached thereto for connection to an electrical conductor. The current conducting strip I8 is connected to the fixed contact 4 as shown in Figures 9 and 10. When the switch is closed the current thereby passes through contact 4, the contact bridge 6 to the fixed contact 5 which is connected to th current conducting trip 24 located on the upper face of the base. This strip as shown in Figure 2 terminates in an upwardly extending leg 25 which is connected to a contact piece I06 in turn connected with the innermost winding of the magnetic coil 1. If desired this contact piece I06 may be integral with this innermost winding or integral with the leg 25. On the opposite half of the base, that is on the left half as viewed in Figure 8, there is a current conducting strip 26 having a threaded bore 21 therein on which may be mounted a contact strip I9 by means of screw I09. This strip I9 carries a contact terminal 2I' in a manner similar to the aforedescribed arrangement. This contact strip I9 is the conductor to the negative pole and the strip 26 includes an extension 28 projecting upwardly into a recess 29. This extension is provided with a threaded bore 30 as shown in Figures 8 and 10, for cooperation with a screw 3 I mounting the bimetallic member 9 as shown in'Figure 1. This bimetallic member is connected with the bent end 32 of the outermost winding of the magnetic coil I. The current therefore flows from contact terminal 2I. through the strip I8 and a conductor 23 through

contacts

4, 6, 5 thence through the leg 25, strip 24 to the coil 1 and through the offset end 32 of the coil I, the bimetallic element 9 of the strip 26 thence through the electrical network involved. The switch base is also provided with openings 33 through which threaded screws may pass for fastening the base tothe wall or rod. Therefore, as indicated, as long as the contact bridge 6 engages the respective fixed

contacts

4 and 5 current will flow through the switch mechanism.

As indicated in Figures 2, 3 and 9 the

electrical contacts

5, 6, 4 are disposed in the contact chamber generally denoted at 9. This chamber includes a box like part 34 the rear wall of which is, open as shown in Figure 9 and the front wall of which is provided with extensions 35. On the narrow sides of the contact chamber are provided air holes 3'I and cooling ribs 33 extend into the interior of the chamber. This box like part or subhousing 34 is closed at its rear by a smooth rear wall 39 as shown in Figures 2 and 3. which wall abuts the leg II of the lower U frame 2 and is held thereby. The contact bridge 6 is secured to a contact rod consisting of two

cheeks

40 and 4|, Figures 2 and 7,. and which checks holda actress 42 "therebetween which carries by means a compression spring acting longitudinally of thestrip the contact bridge 6; The strip or rod 42 is connected to the cheeks by rivets not shown. since these rivets are conductive they are covered by insulating the plates 4-3 shown in Figure 7. The insulating plates and the contact cheeks Ail and M are provided with aligned apertures thrdu'g'h which passes a pin 44 connecting thorn to the switch lever 45 and the connected plates and cheeks are otherwise guided by the marginal edges-430i an opening 4'! in the upper wall of the hot: like part constituting the contactcharn- 3. This isshown in more detail with respect to the modification shown in Figure 28. Oh the rear wall of the contact chamber 34 lies the magmore son I. This soil has a core '58, Figure 2, arranged in a frame carrying the coil and which frame consists of a cylindrical section 59 and a siibstantially flat end section 5i? shown in elevatlon in Figure 6 which includes on its front face switch strips 51 and 52. The part 58 terminates at its lower end in a projecting part 53 through which extends contact piece H13 connected with the leg -25 of the current strip 2 The strips 5% and 52 constitute projecting ledges or guides and serve to fix the coil frame and abut on both sides the arms 54 of the front leg is of U frame 2 as shown in Figure 1. These-arms 5d are provided at their lower extremity with legs or bends constituting lugs '55 which are fastened by means of screws 56 to the base i. For fastening the rear leg H of the U frame 2 to the base this leg H is provided on its lower end with a hook like,

extension 51, Figures 2 and 4, which is inserted from above into a'slot 58 in the base and upon subsequent lateral displacement abuts with the "face 51a contacting the lower side of the base i. In assembling the switch, the frame 2 is laterally displaced to engage the hook beneath the base before the arms 5 of the front leg in are secured by the screws 56. The two arms 54 are also pro viddwith outwardly projecting lugs 59, Figure 1, through which an axle 60 is passed. The magnet armature 3 is also provided withcorr'espond mg lugs GI and is swingably mounted on the axle Gil under the influence of a spring not shown. The arms 56 of the front leg ill also define a recess 62 into which the armature B may tilt. To limit the motion of the armature toward the boil the same is provided on its sides with lugs 63 which abut against the adjacent arms 5 of the U frame when the armature is attracted by the magnet against the force of the spring.

vl'ithin the upper U frame [3, it and I5 the mechanical switch mechanism is arranged. Through a recess '64 provided in the front leg l i aswlng lever 65 integral with the magnet ar mature extends. This swing lever imparts a blow against the under side of a tensioned knee doi'nt linkage comprising three links and shown in more detail in Figures 22 and 24. The linkage includes a first link 66 which is u shaped in sectiongand rigidlyattached by means of an axle 6? to a handle 68, the lever arm 69 of which projects through a slot 10 on the upper side of themeing it. This link 56 is mounted in a correspondingly shaped recess "H in the handle 58 so that at most the link canturn relative to the handle to only a limited extent. Between the legs of this link 66 is mounted a bar 12 adapted to contact with and influence a swing lever 13 which is provided on its lower end with a bore 14 by meansof which it is fulcrurned on a pin Ma caraiecl-bythe arm 54 of front leg Ill Figure 1; This swing lever 13 as shown in Figure 7 extends through a slot 15' in the abut-ting faces 12 and 13-0-1? the two U frames. A pin 16 pivots swinglever l3 to the second link 11 of the knee joint linkage which latter link in turn is pivoted by pin 18 on the third link 19 of the linkage. As shown the second link- 11 which is of U-shaped section is provided on its upper side with a lug as abutting the third link 19 as soon as motion of the linkage has passed slightly beyond dead center between the second and third links, FIT? and 19.

Additionally, the second link Tl has on its lower edge a laterally extending lug 81 projecting into the interior of the housing so that the hammer lever 65 integral with the magnet armature canabut against the same from beneath. As the lever arm 69 is swung to the right the linkage is displaced to the left, compare Figures 6 and 25, to such an extent that the knee joint formed by link 11, swing lever 13 and the U link 66 passes slightly beyond its dead center. In this position, Figure 25, in which also a knee joint 7 11, I9 has moved slightly beyond its dead center the knee chain therefore is in a substantially rigid condition. Through a bore 82 in the third link 79 passes a pin 83 which pivotally connects the third link 19 with the front leg 84 of theswitch lever 45. As shown in Figures 11 to 13 this lever 45 is of U-shaped section and by means of bores 85 is swingable about pin 85a fastened'in the

legs

14 and 15 of the upper U-frame. The rear or longer leg 35 or" switch lever 45 has a :bore 81 through which passes a pin 44 which holds the contact cheeks 4.! constituting the contact -carrying bar. The leg 85 of the switch lever 45 is also provided with an angularly offset portion 288 the edge of which abuts against leg i5 of the upper U frame to limit the counterclockwise movement of switch lever 45, see Figure 6. On the upper face of the switch levers are provided two :bores 89 and 90 serving to fasten pawl springs 8| and t2. Pawl spring 9! is very strong and engages at its lower end with the axle lllil rigidly mounted between the legs 14 and E5 of the upper U .Irame and ends ;to turn switch lever '45 counterclockwise; that is, it urges the same from the position shown in Figure 25 to that shown inFigure .6; spring 92 engages at its lower end 'an angular flange 95 of thevharnmer lever 95 for the ithermic cut out. This hammer lever, as shown in .detail in Figures 14 to 16, is pivoted by :meansof :a .pin 96 to the front leg 14 of the upper U frame and includes an upstanding lug portion '9] disposed in the recess 64 of the front .leg and engaging behind this leg so that it isguided thereby. At the lower end of the hammer lever :95 is a laterally projecting boss or lug ill! adapted to influence the annular part ti of thesecond link 17 of the knee joint linkage. Spring 91 tends to .pull hammer lever 95 upwardly about pin 96 as soon as looking pawltil, shown in detail in Figures 17 and 19, is disengaged. This pawl 99 pivots on axle we and includes a nose portion 10! engage ing over the angular portion of hammer lever 95. This nose releases the hammer lever for upward movement as soon as the pawl 99 turned counterclockwise. This counterclockwise movement is imparted thereto by the bimetallic element 9 which through an adjustable screw I 02 presses against the lower end of the pawl :99. For insulation purposes :an insulating plate 194 is provided along the lower endof the pawl 99. The switch'is placed in operating position, Figum .25, by swinging lever .69 from ,left tori'ght,

compare Figures 1 and 6, whereby spring 9| is tensioned. If current rises above a predetermined value so that the bimetallic element 9 bends, due to being heated, the pawl 99 is disengaged and hammer lever 95 is released which urged by the spring 92 strikes from beneath against lug 8| of the link 11 of the knee joint linkage. The linkage jumps up thereby permitting switch lever 45 to follow the influence of spring 9| and move counterclockwise so that contact bridge 6 is suddenly elevated and breaks a circuit over

contacts

4 and 5. After the upward movement of lug ill the direction of pressure which the second link 11 of the knee joint linkage exerts on swing lever 13 is different from that exerted in the dead center position so that swing lever 13 can now rotate U-shaped lever 66 and handle 88 about pin 61 and the switching mechanism is moved to the position shown in Figures 1 and 6. This mechanism therefore provides through the action 01' the bimetallic element a thermic cut-out in the event of overload.

If a short circuit occurs which is a sudden overload so that the magnetic force of coil 1 is abruptly increased, the armature 8 is attracted thereby swinging hammer lever 65 so that the latter hits beneath the angular portion or lug 8| of the knee joint linkage to perform an effect similar to that described with reference to the thermic cut-out. The latter movement, that is the blow of the hammer lever is more enhanced by the fact that its extreme end also strikes directly against the lower edge I01 of arm 84 of switch lever 45 which as shown in Figure 11 is angled so that the hammer lever imparts direct counterclockwise movement to the switch lever.

With reference to Figure 28, there is illustrated a vertical section through a modified form of contact chamber denoted as 3a. The rear wall of the latter is integral with the cylindrical part 49a constituting a coil sleeve while the fiat part 50a is a separate piece. The magnet coil 1 may be either wound directly on the cylindrical part 43a or may constitute a packaged coil so that it may be slipped on. The coil sleeve 49a or the coil sleeve 49 of Figure 2 does not necessarily have to have a cylindrical form and can be square or polygonal.

With respect to the second embodiment illustrated in Figures 26 and 27 there is shown an automatic switch in which the mechanical switch mechanism is again spatially separated from the parts subjected to electrical stress and arranged in a housing part lying above the housing receiving the electrical components. The upper and lower housing parts have equal rectangular cross sectional areas. In this modification there is further illustrated a triple division of the lower housing providing an especially eflicacious space saving construction. Additionally the base structure is of particular advantage. In Figure 26 the housing consists of a lower part II I, a partition H2 and an upper part H3. The one piece lower part has in its first third area a contact chamber H4 which is separated by a wall H5 from the remaining space of the lower housing part III. To partly separate both spaces a flange H6 of partition I I 2 projects beneath the upper terminal edge of partition H5 to provide a labyrinth seal. In contact chamber H4 are mounted the two stationary contacts H1 and the movable contact bridge H8 which is connected to the switch mechanism denoted generally at I33. A T-shaped post H9 projects into contact chamber H4 and includes a front cross plate II9a which guides the movable contact bridge I I8. The web of this T-shaped post prevents the joining of arcs emanating from contacts I I1. Behind the front cross plate I I9a lie two ferromagnetic sheets I20 which on the one hand constitute the counterpole for the magnet coil I2I and on the other hand serve as a cooling means for the arcs. In order to provide in the switch I33, space for the necessary knee joint linkage, not shown, the movable contact bridge H8 and thereby the two fixed contacts II1 are arranged eccentrically of a lengthwise centerline of a switch as shown in Figure 27. The metal thread of the housing part III is occupied by the magnet coil I2I and also houses the coil I22. Upper and lower flanges or ledges I23 and I24 form respectively on the base of the housing III and the partition H2 hold the magnet spool so that additional fastening means are not necessary. The last thread of the area of housing part III constitutes chamber I25. The magnet armature I21 is movable in this chamber and as shown projects through a slot I26 formed in partition H2. The magnet armature cooperates with the core I22 and acts in a manner similar to the action of the armature 8 in the first embodiment on the release mechanism of switch I22. A push button I28 is attached to the armature I21 to provide for manual current breaking operation of the automatic switch if desired.

On the lower side of the chamber I25 a contact strip I29 is inserted for connection to the electrical circuit and which strip carries the bimetallic member I30. Between the armature I21 and the bimetallic member I30 is a lever constituting a part of the thermic release device. As the bimetallic element bends under the influence of heat the lever I3I is moved by the adjusting screw I32 and thereby effects release of the switch mechanism.

The lower housing part III is fastened to the base I35 which latter has on its narrow sides projections I36 ach of which is provided with an aperture I31 through which can pass screws or other means for securing the base to a switch board or the like. Likewise the projections also mount the ends I38 of contact strips I29. Contact screws I40 are provided for connection to the electrical conductors and these screws lie along side the mounting apertures I31. Beneath the screws bores I4I are provided. A push button 3 I39 serves to connect the switch contacts in a manner similar to the handle 68 of the first embodiment. In Figure 26 the contact rod or strip I29 on the left side of the figure denotes the electrical connection to one of the fixed contacts I I1.

The advantages rising from a standardization of the heights of the width ratios of special types of switches of the structure as described in the foregoing is explained with reference to Figure 29. In this figure the distribution chamber or the meter board III is provided with automatic switches I14 and I15 provided with connecting contacts I12 and I13. The narrower switches I14 are for lower current values up to about 15 amps; along side of these narrower switches are additional automatic switches with housings I15 of double width and which larger switches are for higher current values or can constitute switches of a special type such as a zero cut-out, signal contacts or the like. With standardization of size components as regards housing dimensions as shown it is possible to substitute for each large automatic switch with the broad housing I15 two switches with the smaller housing I14. It is further possible to replace two of the 9 narrow: switches with, one. lanc sw tch... Thus with attired? izes! m in or distribution. heard. any combination of narrow and. ide w ch? housin s man e effe ted:

In connection with the substitution of two narrower switches for a wide switchl'i-o the substitution; is, possible, whenthe narrow switch, is less: than half the width; of the larger switches. In: practice: the width; of. the narrower switches mustbesomewhat l ess, that is, one-halt to, 1, mm. less; than; one-half, the; width of the. wide; switch hou in in edue to ina cu a ie o p o ucticm and assembly it, would notbe possible to mount ei ht narr wswitches, in he same p e as, four Wideswitches.

The; advantages resultinggfrom the presentin vent-ion are; e ilv apparent in e m t r oard and distribution, boards can. be equi ped with, a number of; automatic switches, I'M, do ble: the usual.- numberas regards space factors and his possible; to use bothtypes of switches on the, same board. adjacent one another and further toar t lv s lect any c nation of narrow-- and-wide housing switchesisince with thedimension requi e e ts satisfi d n manu a tur distribution; boards can be standardized and accoili lodate any arrangement of switches necessary for the particular electrical network or'networks. involved.

It, is therefore; clear-that there has been provided an automatic switch in which the mechanicaland electrical: components arerespectively spatially separated; in a housing and; which switch providesnot only; for thermic cut-out on overload, but also a magnetic out-out for a sud.- derr overload or short, circuit. and; in; which the structural components of the switch are so dimensioned and arranged,within the housing that therectangular cross. sectional area. occupied by these parts is no larger than the cross sectionalarea of; the base. Thereis further provided a. switch, structurein which abutting: oppositely disposed U frames. house the respectivemecham icali and electrical components in spaced relation with apertures provided between the abutting portions: of the U. frames permitting move-s ment of themovable contact carrying bar and the triple levers.

Additionally, I- haveprovided a switch arrange-,

ment embodying a knee joint linkage operable in connection with circuit breaking movement to move the movable Contact carrying bar and in which, the means responsive to thermic cut-out and. the means responsive to magnetic cut-out both include elements cooperatingwiththe same element of the: knee joint linkage. but in. a dife ent m nne Having describedmy invention, whatI claim is:

1;. an automatic switch including a, rectangw iar base, means defining a: contact chamber there-above, at, least one fixed contact in said chamber, a movable contact normally biased to open, position; and cooperabletherewith, mes Char w t hin me n m oper blv conn cted with said movable Contact for; moving the same to and; holding the same in circuit closing position, current overload releasemeans co-. operable with. said; mechanism to. permit reverse movement, of; said contact to circuit breaking position and superposing housings. respectively. receiving and; separating; the said mechanism from. the contacts, and. said housings comprising, oppositely arranged upper and lower U.- frames including high-t. portions abutting; one an other.

- 2. Anautomatioswitch including a rectangularbase, means defining a. contact, chamber there-- above, fixedaqontact, means in said chamber, move able contact means cooperable therewith and normally. biased. to circuit, opening position and including means constituting a contact carrying, bar, mechanical switch mechanism operably. connected. with, said: bar for moving the same and thacontact means associated therewith and hold-i ing tbesameincircuit closing position, current overload releasemeans cooperable with said.- mechanism. to permit reverse movement of said bar to. circuit breaking position, superposed housings, respectively receiving and separating the said mechanism. from the contact means and the, overload release. means which latter two means constitute switch,componentssubjected to electrical stress, said. mechanism and said. componentsv occupying equal cross sectional: areas, said mechanism including a switch lever connected, to said bar and means biasingv the lever and thereby the bar, to circuit breaking position, a three part. kneejoint linkage including a first link, a. handle, connected thereto, an intermediate link, and a third link operably connected with said switch lever whereby, swinging move.- ment of said handle movessaid linkage to thereby move said switch lever and the, contact bar. carried thereby to circuit closing position and said overload release means constituting input a magnetic coil. in the circuit, an armature associated therewith and a hammer lever embodied with said armature and operable whenthearmature is attracted by the coil due to sudden, cur. rent overload to displace said linkage to permit said biasing means to move said contact bar to circuit breaking position.

3. An automatic switch as defined in and by claim 2 in which the intermediate link is pivotally connected with the third link and a lug adjacent to the pivot connection is disposed inthe path of movement of the hammer lever embodied with the armature and engaged thereby when thearmature is attracted by the coil.

4. An automatic switch including a rectangular base, means defining a contact chamber thereabove, a fixed contact means in said chamber, movable contact means cooperable therewith, means constituting a contact carrying bar for said movable contact. means, mechanical switch mechanism operably connectedwith said bar in,- cluding biasing means normally urging the bar to circuit breaking position and activating means for moving the bar to circuit closing position, current overloadrelease means cooperating with said mechanism to release the same permitting reverse movement of said bar to circuit breaking position, superposed housings receiving and separating the said mechanism from the contact means and the overload release means, said housings comprising oppositely arranged upper and lower U-shaped frames including bight portionsabutting one another and parallel front and rear leg means, said overload release means including a magnetic coil, an armature pivotally mounted on the outer face of one of the leg means of the lower frame, said. coil abutting the opposite face of said leg means, said leg means having a recess therein into which the armature may move, a hammer lever rigid with the armature and movable therewith, and the upper U-frame receiving the said mechanism having an opening'. through which the hammer lever extends for cooperation with said switch mechanism.

5.. An. automatic switch as defined in and by claim 4 in which the armature is provided with lateral extensions projecting beyond the margins of the recess in the leg means on which the armature is mounted for abutting said leg means to limit the movement of the armature towards the coil.

6. An automatic switch as defined in and by claim 4 and casing surrounding and encompassing both said housings, lug means extending outwardly of the said leg means supporting the armature, a pivot means for the armature supported by said lug means and said lug means extending outwardly of the leg means toward and terminating closely adjacent the casing.

7. An automatic switch as defined in and by claim 4 including a frame carrying said coil, said frame abuttin the face of the said leg means supporting the armature and including project-- ing strips laterally abutting said leg means.

8. An automatic switch as defined in and by claim 1 in which each of the U-frames includes parallel leg means, screw means connecting one leg means of the lower U-frame to the base, the said base having a slot therethrough subjacent the opposite leg means of the lower U-frame and said opposite leg means having a hook on the bottom thereof cooperable with the base after passage through the slot and lateral displacement with respect thereto.

9. An automatic switch as defined in and by claim 8 in which the base projects beyond the narrow sides of the housing and the projecting portions each having a screw receiving aperture therethrough and a contact strip adjacent to said aperture.

10. An automatic switch as defined in and by claim 1 in which the U-frames include opposite leg means, open ended subhousing constituting said contact chamber between the lower leg means and a thin insulating partition closing said chamber and abutting one of th leg means or the lower U-frame.

11. An automatic switch as defined in and by claim 10 in which the means defining the open ended housing includes a longitudinal wall parallel with the major axis of the base and transverse walls parallel with the minor axis of the base, the current overload release means including a magnetic coil in the circuit controlled by the contacts and an armature associated therewith, said coil abutting said longitudinal wall and the said longitudinal wall having ends projectin beyond the transverse walls and the said transverse walls having air passages therein.

12. An automatic switch as defined in and by claim 2 in which the means constituting the contact carrying bar comprises spaced cheeks, a strip connected therebetween, a compression spring connected to said strip and the movable contact means constitutes a contact bridge carried by said spring, said contact chamber having an opening in the upper portion thereof, insulating plates carried on the outer surface on each of said cheeks and said cheeks and plates passing through said opening and being guided by the marginal edges thereof.

13. An automatic switch as defined in and by claim 1 in which the current overload release means includes a bimetallic element and a magnetic coil both in the circuit controlled by said contact means, said switch mechanism including a locking pawl, one end of said bimetallic element being free and adapted to abut said pawl when the said element flexes due to current overload.

said base having a recess therein, a current conducting strip in said base and extending into said recess and means directly connecting the opposite ends of said bimetallic element to said strip.

14. An automatic switch including a base, means defining a contact chamber thereabove, fixed contact means in said chamber, movable contact means cooperable therewith and normally biased to open position, mechanical switch mechanism operably connected with said movable contact means ior moving the same to and holding the same in a circuit closing position, current overload release means cooperating with said mechanism to permit reverse movement of said movable contact means to circuit breaking position, superposed housings respectively receiving and separating the said mechanism from the contact means and the overload release means, said latter two means constituting components subjected to electrical stress, said base being rectangular in plan and the mechanism and components occupying substantially equal cross sectional areas, the housing receiving the said component comprising three chambers, the first defining said contact chamber, said overload release means including a magnetic coil, the second chamber receiving said coil and an armature associated with said coil and a bimetallic element constituting part of said overload release means in said third chamber.

15. An automatic switch as defined in and by claim 14 in which the contact means are mounted in the contact chamber, a term-magnetic sheet in said chamber and axially spaced from said contact means, an insulating partition separating the same from said contact means, and said sheet extending perpendicular to the axis of said coil in said second chamber so that said sheet constitutes a magnetic counterpole for said coil.

16. An automatic switch as defined in and by claim 14 in which spaced contacts constituting the fixed contact means are disposed in said contact chamber, the movable contact means comprises a movable contact bridge, spaced ferromagnetic sheets extending parallel with the major axis of said bridge and disposed in said contact chamber in spaced relation from said contacts, an insulating partition between said sheets and said contacts and an insulating strip extending perpendicular to said partition between and separating said sheets.

17. An automatic switch as defined in and by claim 14 and a sleeve for said coil constituting an integral part of said contact chamber.

18. An automatic switch including a base, means defining a contact chamber thereabove, at least one fixed contact in said chamber, a movable contact normally biased to open position and cooperable therewith, mechanical switching mechanism operably connected with said movable contact for moving the same to and holding the same in circuit closing position, automatic overload release means including an electro-magnetic coil for opening the circuit in case of a sudden heavy overload, as well as a thermostatic member for opening the circuit in case of a prolonged lesser overload, said electro-magnetic coil and thermostatic member cooperable with said switching mechanism to permit reverse movement of said movable contact to circuit breaking position, and superposed housings respectively receiving and separating the said switching mechanism from the switch elements comprising the contacts, the electro-magnetic coil and the thermostatic member which are subjected to References Cited in the file of this patent electrical stress.

19. An automatic switch as defined in and by UNITED STATES PATENTS claim 18, in which the said base is rectangular in Number Name Date plan and the mechanical switching mechanism 5 50 07 Wulsten 14, 1939 and the switch elements subjected to electrical 2540491 Rowe t a1 6, 1 51 stress occupy equal cross sectional areas.

20. An automatic switch as defined in and by FOREIGN PATENTS claim 19, for low current loads having the same length factor but at the most half the width 10 533 gfgfig g g factor of switches for higher current loads.

WILHELM LEYHAUSEN.