US2423099A

US2423099A - Electric switch

Info

Publication number: US2423099A
Application number: US616073A
Authority: US
Inventors: Stephen S Grady
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-09-13
Filing date: 1945-09-13
Publication date: 1947-07-01
Anticipated expiration: 1964-07-01

Description

2 Sheets-Sheet l ATTORNEY ad 1w 2 M w 14 w 5 6 0 /6 /6 2\7 9 W4 5 i fi 7 m 9 iL @22 w r W5 e o 3 w @Q 5b c Q J w 31%.

July 1, 1947.

Filed Sept. 13, 1945 July 1, 1947. s, s GRADY 2,423,099

ELECTRIC SWITCH I Filed Sept. 13, 1945 2 Sheets-Sheet 2 ATTORNEY Patented July 1, 1947 UNITED STATE 5 RAT-EN OFF [CE ELECTRIC SWITCH- Stephen- S. Grady, New 21011:, N: iYI:

Application September 13,. 1'945,.Serial No;.61'6,073 I:

(Cll 200 -46-Y l '15 Claims. 1;

This inventionrelates to electric switches in general and more. especially to two-way switches, either for.alternatelyconnecting a common generatorto one. or another of two power lines, or for alternately connecting a single power line to one or .ailotherof two generators.

Among. theobjects of the present invention, it is aimed to provideaniirnproved two-way electric switch having a common fuse when the switch is either of its two closed positions and a slidable interposer actuatable either into neutral position or into either of. the two closed positions ofthe switch.

It is still another objectof the presentinvention to provide an improved electric switch having a pivoted handle for actuating an interposer into andout of closed position and a switch'box having 'acover cooperating with the handle so that thebox or cover. of the box cannot be opened without first actuating the switch handle into neutral or open position, and in turn whereby the opening of the cover will force the handle into neutral or open position if it is not already in neutral position.

t is still another object of the present invention to providean improved electric switch having a pivoted handle for'actuating an interposer into and out of oneoi two closed positions and a switch box havinga cover cooperating with thehandle so that the 'box .or cover of the box cannot be opened without first. actuating the switch handle into neutral or open position, and in turn whereby the opening of the cover will force the handle .into neutral or open position whether the handle is inuone or the other of its closed positions, if the handle is not already in neutral position.

It is still .another object of the present invention to provide an improved electric switch hava pivoted handle for actuating an interposer into and out of closed position, and a switch-box having a cover and anchoring means locking said handle in neutral position when said cover is being removed or is removed and the cover will cooperate with said anchoring means to free said handle when .said cover is actuated into closed position.

It is still another object of the present invention to provide an improved electric switch having .a pivoted handle for actuating an interinto and out of closed position and a s chhox having. a cover, said handle consisting of two pieces pivoted to one anotherto enable folding one piece into compact arrangement with the switch unit when the cover is removed 211;- to' conserve space-when shipping the switch and alsotoaifordjaccess-to a centrally located iu'sew It is still another" object of the-present invention to provide an improved-electric switch hav- "ing a plurality of parallel fuses with blade-enrls to cooperate with flexible cla'mping- *jaws; and a bar constituting a fuse puller in anchoredpositl on securing gthe "several fuses from -"being accidently -jarred'loose; saidbar having a pin formed "to; enter any one' of' the -*-jaws when the bar'- ireed tocooperate with a *b'la'de end andremcve a fuse;

These and otherfeature-s; capabilities and advantages of "the-present invention will *appear "from: the *subjoined 1 detail description of" 'one specificembodiment"thereoi'* i1lustrated-- in the accompanying drawings in which Fig. '1 is I a side elevation -pai'tly in section" of a switch heir and -electric 'switch- 'ma de' -accordin to the- -'present' invention Fig-:12 is a plan view o? the electric "switch slightly enlarged as to 'tliescale of Figs-1;

actuate electric switohes of two; three and even four associated--=conduotors-;- as "fo'rinstancea two-wire direct current circuit, -a three-wire hookup: for a three-phase alternatirig --current hookup or a four-wire hookup for a four-phase alternating current hookups The-features of the present invention areadapte'd-to any one of these hookups;-an=d--merely by. way-of examplepin Fig.

2," there is illustrated an 'electric' -=switch *construction adapted ior i thi ee "electric SWitOl'lGs of three-associated conductors wo' wit the 'electric switches l, 2 and 3.

Since each of the electric switches l, 2 and 3 "is I substantially identical with one another,- only oneswitch, to' wit theswltch 2 will b'de'scribed inrletail, and -the like parts in ele'ctricswitches l and 3 will have-the same reference characters applied.

As shown-in Figs. 2 and-4gthere=is provided a.

base 4 composed of" some suitable insulating material common to all three. switches I52 and 3,

and it is provided with "

projections

5, 5 secured to thebase-wal1 6 of the -switch' "b0x .1 which in "turn-is provided with end-walls '8 and ifithemall 8 having pivotally connected thereto, by the hinge I9, the cover II, which is provided with an overlapping or extended portion I2 having an opening to receive the hasp I3 riveted to the flange I4 of the wa11 9. When the cover II is in closed position shown in Fig. 1, where the hasp I3 extends through the extension I2, a conventional padlock I5 may be secured to the hasp I3 to lock the cover II in closed position.

When three switches, as an instance, the switches I, 2 and 3, are associated, they are spaced from one another by the longitudinally extending bars I6 and I1 composed of insulating material, with the bar I6 between the switches I and 2 and the bar I1 between the switches 2 and 3.

Extending transversely across the bars I6 and I1, there are provided the two plates I8 and I9 composed of insulating material, separated from one another and mounted on blocks or enlargements 23 composed of insulating material extending from the bars I6 and I1. Mounted on the transverse plates I8 and I9, there are provided the cheek plates 2I and 22 composed of insulating material and in alinement with the bars I6 and I1 respectively to form stalls or working spaces for the switches I, 2 and 3.

With particular reference to Figs. 2 and 4, each of the switches I, 2 and 3 is provided with a main contact plate 23 secured to the base plate 4 and provided with a terminal 24. This contact plate 23 extends from one end of the base plate 4 ap-. proximately two-thirds the length of the base plate 4 and has a raised portion 25 with two cam faces .26 and 21 at the ends of the raised portion 25. This raised portion is disposed in the present instance about midway between the transverse plates I8 and I9. The transverse plates I8 and I9 have mounted on the same the U-shaped

contact plates

28 and 29. Thelegs 39 and 3I of the

contact plates

28 and 29 respectively are sub- 33 are secured to the

plates

36 and 31 respectively secured to the faces of the bars I9 and I8 extending away from the

legs

30 and 3|. Between the plates 3'6, 31 and the bars I9, I8, preferably there are secured the

webs

38 and 39 of the

fuse clamping jaws

49 and 4| respectively.

The

plates

36 and 31 have the

flexible contact portions

42 and 43 respectively extending toward one another in the space between the

plates

32 and 33, the

plates

36 and 31 having

inclined shoulders

44 and 45 respectively for the purposes hereinafter to be described.

The U-shaped contact plate 28 is insulated from J the edges of the

plates

32 and 36 by the sheet 46 composed ofsome suitable insulating material and preferably extending up inside of the U- shaped plate28 around the free edge of the plate 32, one portion of the bar I9 and then upwardly between the opposing edges of the plate 28 and -plate.36. Similarly, the U-shaped plate 28 is insulated from the plate 33 and the plate 31 by the sheet 41 composed of a suitable insulating Ematerial which is disposed on the inside of the plate 35 and between the upper edge of the plate 35 and the plate 29 and then up over a portion i of the bar I8 to extend between the opposing edges of the plate 29 and the plate 31.

Mounted to slide on the bars I6 and I1 is the plate 48 composed of insulating material and having around its edges the U-shaped

contact plates

49 and 50.

The plate 43 in the present instance is common to the three switches I, 2 and 3 but each of the switches has an individual pair of

contact plates

29 and 53.

For operating the plate 48 and its three sets of

contact elements

49 and 50 commonly known as an interposer, there are provided the two-arms 5i and 52. The bars 5I and 52 are pivotally connected by the

pins

53 and 54 to the upper ends of the cheek plates 2I and 22' and the lower ends of the bars 5i and 52 are enlarged, see Fig. 4, and have three fingers, 55, 56 and 51 cooperating in three openings formed in the plate 48. The arms 5I and 52 are operatively connected to two

springs

58 and 59. These springs are substantially identical to one another and cooperate with the arms 5i and 52 to anchor the arms in neutral position against accidental displacement and also to anchor the arms in either of its two circuit closing positions and still furthermore cooperate with the arms to effect a quick opening and quick closing in order to reduce arcing to a minimum.

The spring as an instance has one arm 60 disposed against the screw 6| constituting an abutment secured to the cheek plate 2!. This arm makes a single turn around the screw 62 secured to the cheek plate 2! and then passes over to and under the projection 63 on the arm 5i and terminates beyond the projection 63 in the free arm element 64. The wire 58 isbent at 55 to form a seat for the projection 53 when the arm 5! is in neutral or open position of the switch. The portion 66 of the wire cooperates with the abutment 63 to lock the arm 5| in one closed position, and the arm portion 64 cooperates with the abutment 63 to anchor the arm 5! in its other closed position.

The wire 59 of the arm 52 is similar to the wire 59 except that it is not in alinement with the arm 53 but to a certain extent is the complement oi the wire 58, the wire 59 having an arm portion 51 abutting against a screw similar to the screw 55 and. then making a complete turn around another screw similar to the screw 62 and then extending down along the cheek plate 22 and engaging the abutments 63 in the arm 52, the abutment 53 being similar to the abutmerit on the arm 5!. The wire 59 also has a depression forming a seat cooperating with the abutment 98. It will be noted, however, that in the present instance, the arm 60 of the wire 58 extends adjacent to one end of the cheek plates 2i and 22 while the similar free arm of the wire 59, see Fig. 2, extends adjacent the other end of the switch. By this arrangement of the springs, the tension on the arms 5I and 52 to maintain them in either closed position will be substantially equal. 4

In order to actuate the two arms SI and 52 by a common lever, the lever handle 69 is provided mounted on the blade 19 which is pivotally connected at one end to the arm 52 and slidably connected in a recess in the arm 5i. When the handle 89 and blade 15 are positioned in the full line position shown in Fig. 3, the handle 69 is ready to actuate the arms 5i and 52 into either of its closed positions or into neutral position. When it is desired to ship the switch, however, in order to conserve space, the handle 69 is swung edge of the cheek plate 2|.

down into the dash and dotlline position show in Fig. 3 ad-jacentthecheek plate 22..

In the present instance, the arm is provided with an extension having a finger .72 to rest-inthe-recess I3'formed in thespring plate-l4 which is secured-by the spring I5 to the upper The spring plate "l4 when its recess receivesthe pin i2 yieldably maintains-thearms 5| and52 in neutral position. The spring plate 14: has a pro'ection it which, seeFig-l, will be'engaged-by the cover ll to depress the spring-plate l4 and thereby free the finger 1:2 from-the recess 13.

As will be herein-after described, the cov r 5 cooperates with the handle 69 -tobring it into neutral position before thecover H can be re 1noved.- When it returns the arm or handle B l 'intoneutra-l position, then the linger will register with the recess l3 and consequently immediately that the cover II is raised, the spring plate I l will flex outwardly and receive the finger-l2 andanchor the arms 5| and and the "handle B9=inneutral position. When it desired-to release the handle -69, it will be necessary to hex the spring plate 14 toward the cheek plate 2!. I This flexing can beachieved by merely closingthe cover linto the position shown in Fig. 1.-

The handlefifi, see Fig. 1, has an enlargement 16 with a cam face Tito cooperate with the edge "I8" ofthe-slot-IS in the cover Ii. The rear edge 99 of the handle 69 will in turn cooperate with the edge 8| of the opening 19. In other words, whenthe cover H is in closed position, the main die 69 extends through the opening is. The

opening 19 is so conformed that the handle Gil can -'be moved into either of its circuit closing positions, when the cover H is closed, but when the cover H is swung around its hinge it into open'position, if the handle 69 is in either of its closed. positions, then either the edge l8 of the opening 19 will cooperate with the cam face ll of the handlett or the edge 8! of the opening '19 will cooperate with the edge-B8 of the handle lifiinitially to return the handle 69 to its neutral position as shown in Fig. 1, when the finger I2 will register with the recess 13 ready to be anchored bythe-spring plate 14 immediately that the cover H clears the extension I5.

Inbperation the handle 59 from neutral position'may'actuate the arms 5| and 52 in turn to actuate the interposer 48 either to bring the contact '49 into engagement with the contact portions 34 and 3D and the contact 53 on the plate 48 into engagement with the contacts 3! and 25 or else swing the interposer48 into the other circuit closing position where the contact will engage the

contacts

35 and 3| and the contact as on :the plate 48' will engage the

contact plates

42 and 25. Looking at Figs. 5 and 6, assume that the binding posts'24 of the three switches l, 2 and 3 are connected to the three conductors oi a generator; then when the handle 69 is swung from neutral into closed position where the interposer 48 causes, see Fig, 5, the contact 49 to engage theplates 32 and 30 and causes the contact 59 to engage the contact plates 31 and then the current will pass from a binding post 2d through the contact plate 25 to the contact 553, then the contact plate 31, then the clip 4! of the fuse, then the fuse 82 and then the fuse clip and from the fuse clip 40 to-thecontact plat the-contact 49 on the-interposer 48'and then the contact plate 3|l-to the-binding post or terminal 83 of the power line connected to the contact sired to remove a fuse 92, the .bar

plate 30. .Inturn, see Fig. .6, whereitxis still assumed that the binding posts 24' are connected to the conductor of a generator and .the interposer 43 is swung into the otherclosed position of the switch, the current .will pass from the binding post 24 through the contact plate 25, then the contact 49 on the interposer '48, then the contact plate to the clip 4t and through the fuse 82 to the clip 4|, and from the clip 4| to the contact plate 31, then the contact plate 33 to the contact on the interposer 48, then to the contact plate 29' to the binding post or terminal 84 of the second power line.

Figs. 7 and 8, it is assumed that there are two generators or two generator systems connected to a single power line. lnFig. 7 it is assnrned that the conductor '85 connected to one generator is connected to the binding post or terminal 83, the conductor 85 of another 1gcnerator is connected to the binding post or terminal 84 and the conductor B! of the power line is connected to the terminal or binding posti l. if the handle .59 is moved into the closing position of the switch shown in Fig. 7, then the contact 355 of th interposer 43 will engage the contact plate 39 and the contact plate 32 and the com tact 59 of theinterposer will engage the

contact plates

25 and 31. Consequently, the generator connected to the conductor 85 will be brought into connection with the power line 8? and the current will pass from the conductor 85 through the contact plate 39 to the contact plate :49 on the interposer 48, then the contact plate 32,..then the contact plate 39 to the clip 40,.frorn theclip to through the fuse 82, to the clip 4| and from the clip ll to the contact plate 3; tothe contact in engagement with th contact plate and from the contact plate 25 out to the binding post it to the power line 81.

In turn if the interposer 423 is swung into t e position shown in Fig. 8, the generator I nected to the conductor E35 will be thrown connection with the power line 87 and the current will pass from the conductor Bil through the contact plate to the contact 59, from the contact 59 to the contact plate 33 to the contact plate 3?, to the clip 45, from the clip 4i thro the fuse 82, from the fuse 82 through the clip to the contact plate 35, from the contact plate to the contact 49 and then to the contactiplate to the binding post 2=i in turn to the power line 83',

The several fuses 32 are ofconventional construction, each having at their

ends knife blades

83 and 89, the blade 83 being adapted to be clamped by a clip iii and the blade :89 to be clamped by a clip 4|.

When the switch as illustrated consists three switch elements, the several in niay be lockedin position by the bar 99, it b the present instance screw-threadedly cm W t to the upper edges of the cheek plates 2i and at by the screws 9| and 92 respectively. in the present instance is preferably with a pin 2 3 so that the bar 9E3 with its 1." may serve a second function. In other words, when the bar99 is in the position shown in Fig, 2, it will anchor the fuses 32 from being a withdrawn. On the other hand, i

- 7- .1 removed and then its pin may be u d to ssed into the space 94, see 3, N- ath the

blade

88 or 85 of afuse 82 and then the pin 523 be caused to press against the blade 19% crate and withdraw upwardly a fus -82.

Furthermore, access is had to the fuse 82 located between the cheek plates 2| and 22 when the handle 69 is swung from the full line position shown in Fig. 3 to the dash and dot line po sition shown in that figure.

It is obvious of course that in place of the fuse 82 of each unit where it may be desired to dispense with a fuse, any suitable conductor such as a copper bar may be substituted, in which case of course the advantages of compactness afforded by the switch here disclosed will still be retained, and the incidental features that flow from such compact arrangement as herein before discussed will also b retained.

It is obvious that various changes may be made to the details of construction without departing from the general spirit of the invention as set forth in the appended claims.

I claim:

1. In an electric switch, the combination of a main terminal, a pair of secondary terminals, and means for alternately connecting said main terminal with either of said secondary terminals, said connecting means including a common fuse, a fuse contact plate connected to each end of fuse, a main contact plate connected to said main terminal, a secondary contact plate connected to each of said secondary terminals, and an in terposer slid'ably mounted between said main contact plate and the contact plates of said fuse and of said secondary terminals, said interposer having two contacts and three main positions, an intermediate neutral position where its two contacts are free, one closed position where one of its contacts bridges the gap between one fuse contact plate and the contact plate of one of said sec ondary terminals, and where the other of its contacts bridges the gap between the other fuse contact plate and the main contact plate, and the other closed position where said other of its contacts bridges the gap between the other of said fuse contact plates and the contact plate of the other of said secondary terminals, nd where in turn the said first-mentioned of its contacts bridges the gap between said first-mentioned of its fuse contact plates and said main contact plate.

2. In an electric switch, the combination of a main terminal, a pair of secondary terminals, and means for alternately connecting said main terminal with either of said secondary terminals, said connecting means including a common fuse and an interposer having two contacts, said interposer being slidable into three positions, a neutral position where its two contacts are free, one

closed position where one of its contacts bridges a gap between one end of said fuse and said main terminal, and the other contact bridges a gap between the other end of said fuse and one of said secondary terminals, and the other closed position where one of the contacts of said interposer closes a gap between one end of said fuse and said main terminal, and the other contact closes a gap between the other end of said fuse and the other of said secondary terminals.

3. In an electric switch, the combination of a main terminal, a pair of secondary terminals, and means for alternately connecting said main terminal with either of said secondary terminals, said connecting means including a common fuse, an interposer having two contacts, and separate contact plates connected to said main terminal, to said secondary terminals and to said fuse, being spaced from one another to form gaps, said interposer being slidable into three positions, a

neutral position where its two contacts are free, one closed position where its contacts close a gap between said main terminal and one end of said fuse and another gap between the other end of said fuse and one end of said secondary terminals, and another closed position where the contacts of said interposer close a gap between said main terminal and one end of said fuse and another gap between the other end of said fuse and said other secondary terminal.

4. In an electric switch, the combination of a plurality of switch units, each unit having a main terminal, a pair of secondary terminals, and means for alternately connecting the main terminal of each unit with either of the secondary terminals of each unit, said connecting means including a fuse for each unit, separate connecting plates connected to said main terminal, to said secondary terminals and to said fuse of each unit being spaced from one another to form gaps, a common slidably mounted interposer having a pair of contacts for each unit, said interposer being slidable into three main positions, a neutral position where its contacts are free, one closed position where the contacts of each unit close a gap between the main terminal and one end of the fuse and another gap between the other end of a fuse and one of the secondary terminals of each unit, and the other closed position where the contacts of each unit close a gap between the main terminal and one end of a fuse and another gap between the other end of a fuse and the other secondary terminal of each unit.

5. In an electric switch, the combination of a main terminal, a pair of secondary terminals, means for alternately connecting said main terminal with either of said secondary terminals, said connecting means including a common fuse and an interposer having two contacts, said interposer being slidable into three positions, a neutral position where its two contacts are free, one closed position where one of its contacts bridges a gap between one end of said fuse and said main terminal and the other contact bridges a gap between the other end of said fuse and one of said secondary terminals, and the other closed position where one of the contacts of said interposer closes a gap between one end of said fuse and said main terminal and the other contact closes a gap between the other end of said fuse and the other of said secondary terminals, a pivotally mounted arm, the free end of said arm being operatively connected to said interposer, and a handle operatively connected to the other end of said arm for actuating said arm and in turn said interposer.

6. In an electric switch, the combination of a main terminal, a pair of secondary terminals, means for alternately connecting said main terminal with either of said secondary terminals, said connecting means including a common fuse and an interposer having two contacts, said interposer being slidable into three positions, a neutral position where its two contacts are free, one closed position where one of its contacts bridges a gap between one end of said fuse and said main terminal and the other contact bridges a gap between the other end of said fuse and one of said secondary terminals, and the other closed position where one of the contacts of said interposer closes a gap between one end of said fuse and said main terminal and the other contact closes a gap between the other end of said fuse and the other of said secondary terminals, a pivotally mounted arm, the free end of said arm being operatively connected to said interposer, a handle operatively connected to the other end of said arm for actuating said arm and in turn said interposer, and a spring for yieldably anchoring said arm in its neutral and closed positions.

7. In an electric switch, the combination of a main terminal, a pair of secondary terminals, means for alternately connecting said main ter-- minal with either of said secondary terminals, said connecting means including a common fuse and an interposer having two contacts, said interposer being slidable into three positions, a neutral position where its two contacts are free, one closed position where one of its contacts bridges a gap between one end of fuse and said main terminal and the other contact bridges a gap between the other end of said fuse and one of said secondary terminals, and the other closed position where one of the contacts of said interposer closes a gap between one end of said fuse and said main terminal and the other contact closes a gap between the other end of said fuse and the other of said secondary terminals, a pivotally mounted arm having its free end operatively connected to said interposer, a handle pivotally connected to the other end of said arm in one position to actuate said arm and in turn said interposer and the other position to be rocked out of the way to conserve space.

8. In an electric switch, the combination of a plurality of switch units, each switch unit having a main terminal, a pair of secondary terminals, means for alternately connecting the main terminal of each unit with either of the secondary terminals of each unit, said connecting means including a. fuse for each unit, connecting plates connected to the main terminal. secondary terminals and fuse of each unit and forming gaps, a common slidably mounted interposer having a pair of contacts for each unit, said interposer being slidable into three maic posit ons, a neutral position where its contacts are free, one closed position where the contacts of each unit close a gap between the main terminal and one end of the fuse and another gap between the other end of a, fuse and one of the secondary terminals of each unit, and the other closed position where the contacts of each unit close a gap between the main terminal and one end of a fuse and another gap between the other end of a fuse and the other secondary terminal of each unit, pivotally mounted arms having their free ends operatively connected to said interposer, a handle operatively connected to the other end. of said arm for actuating said arm, and spring means for anchoring said arm and in turn said interposer in its neutral and closed positions.

9. In an electric switch, the combination of a main terminal, a pair of secondary terminals, means for alternately connecting said main terminal with either of said secondary terminals, said connecting means including a common fuse and an interposer having two contacts, said interposer being slidable into three positions, a neutral position where its two contacts are free, one closed position where one of its contacts bridges a gap between one end of said fuse and said main terminal and the other contact bridges a gap between the other end of said fuse one of said secondary terminals, and the other closed position where one of the contacts of said interposer closes a gap between one end of said fuse and said main terminal and the other contact closes a gap between the other end of said fuse and theother of said secondary terminals, a housing for said switch having a, pivotallymounted cover having a slot therein, a pivotally mounted arm having its free end operatively connected to said interposer, a handle operatively connected to said arm for actuating the same and extending through the slot in said cover when said cover is closed, said cover cooperating with said handle to position it in neutral position before said cover can be swung into open position.

10. In an electric switch, the combination of a main terminal, a pair of secondary terminals, means for alternately connecting said main terminal with either of said secondary terminals, said connecting means including a common fuse and an interpose having two contacts, said interposer being slidable into three positions, a neutral position where its two contacts, are free, one closed position where one of its contacts bridges a gap between one end of said fuse and said main terminal and the other contact bridges a gap between the other end of said fuse and on of said secondary terminals, and the other closed position wher one of the contacts of said interposer closes a gap between one end of said fuse and said main terminal and the other contact closes a gap between the other end of said fuse andthe other of said secondary terminals, a housing for said switch, a pivotally mounted cover on said housing having, a slot, 9, pivotally mounted arm having its free end operatively connected withsaidinterposer to actuate the same, a handle operatively connected to said arm and extending through the slot in said cover, and a spring actuating means for anchoring said handle in neutral, position when said cover is raised, said cover cooperating with said anchoring means to release said handle when said cover is in closed position to enable said handle to actuate said interposer.

11.. In al'l-GIGCtliC switch, the combination of a base, three switch units mounted on said base, each switch unit having a main terminal, a pair of secondary terminals and means for each unit for alternately connecting its main terminal with either of its secondary terminals, the connecting means of each including a common fuse, and connecting plates forming gaps between the main terminal and said fuse and between the secondary terminals and said fuse, and a common interposer having a pair of contacts for each unit, said interposer being slidably mounted into three main positions, a neutral position where the contacts are free, one closed position wher the contacts of each unit close a gap between its main terminal and one end of its fuse and close another gap between the other end of its fuse and one of its secondary terminals and another closed position where the contacts of each unit close a gap between its main terminal and one end of its fuse and close another gap between the other end of its fuse and the other of its secondary terminals, said connecting plates including clips for the ends of said fuses, said fuses having blade ends connected to said clips, said fuses being mounted parallel to one another, and an anchoring bar secured in place across the ends of said fuses to lock the same against accidental displacement.

12. In an electric switch, the combination of a base, three switch units mounted on said base, each switch unit having a. main terminal, a pair of secondary terminals, and means for each unit for alternately connecting its main terminal with either of its secondary terminals, the connecting means of each including a common fuse, connecting plates forming gaps between the main terminal and said fuse and between the secondary terminals and said fuse, a common interposer having a pair of contacts for each unit, said interposer being slidably mounted into three main positions, a neutral position where the contacts are free, one closed position where the contacts of each unit close a gap between the main terminal and one end of its fuse and close another gap between the other end of its fuse and one .of its secondary terminals, and another closed position where the contacts of each unit close a gap between its main terminal and one end of its fuse and close another gap between the other end of its fuse and the other of its secondary terminals, said connecting plates including clips for the ends of said fuses, said fuses having blade ends connected to said clips, said fuses being mounted parallel to one another, an anchoring bar secured in place across the ends of said fuses to lock the same against accidental dis placement, and a finger at the end of said anchoring bar for engaging the knife blades of said fuses when said bar is liberated to withdraw said fuses from said clips.

13. In an electric switch, the combination of a base, two parallel cheek plates mounted on said base forming three unit areas, an electric switch unit mounted in each unit area and including a main terminal, a pair of secondary terminals, means for alternately connecting each main terminal with either of its associated secondary terminals, the connecting means of each unit ineluding a common fuse disposed in each unit area, connecting plates for each unit connected to the main terminal, secondary terminals and fuse, of each unit to form gaps, a common interposer having a pair of contacts for each switch unit, the interposer being slidably mounted into three main positions, a neutral position where its contacts are free, one closed position where the contacts of each unit close a gap between a, main terminal and one end of a fuse and the other end of a fuse with one of its secondary terminals, and the other closed position where the contacts of each unit close the gap between a main terminal and one end of a fuse and the other end of a fuse and the other of its secondary terminals.

14. In an electric switch, the combination of a base, two parallel cheek plates mounted on said base forming three unit areas, an electric switch unit mounted in each unit area and including a main terminal, a pair of secondary terminals, means for alternately connecting each main terminal with either of its associated secondary terminals, the connecting means of each unit including a common fuse disposed in each unit area, separate connecting plates for each unit connected to the main terminal, to the secondary terminals and to the fuse of each unit spaced from one another to form gaps, a common interposer having a pair of contacts for each switch unit, the interposer being slidably mounted into three main positions, a neutral position where its contacts are free, one closed position where the contacts of each unit close a gap between a main terminal and one end of a fuse and the other end of a fuse with one of its secondary terminals, and the other closed position where the contacts of each unit close the gap between a main terminal and one end of a fuse and the other end of a fuse and the other of its secondary terminals.

15. In an electric switch, the combination of a base, two parallel cheek plates mounted on said base forming three unit areas, an electric switch unit mounted in each unit area and including a main terminal, a pair of secondary terminals, means for alternately connecting each main terminal with either of its associated secondary terminals, the connecting means of each unit including a conductor disposed in each unit area, separate connecting plates for each unit connected to the main terminal, to the secondary terminals and to the conductor of each unit spaced from one another to form gaps, a common interposer having a pair of contacts for each switch unit, the interposer being slidably mounted into three main positions, a neutral position where its contacts are free, one closed position where the contacts of each unit close a gap between a main terminal and one end of its conductor and the other end of its conductor with one of its secondary terminals, and the other closed position where the contacts of each unit close the gap between a main terminal and one end of its conductor and the other end of its conductor and the'other of its secondary terminals.

STEPHEN S. GRADY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,905,001 Sachs Apr. 25, 1933 1,839,259 Meuer Nov. 29,1932 2,209,918 Hammerly July 30,1940