US2052059A - Switch mechanism - Google Patents

Description

Aug. 25, 1936. H.' sENGl-:BUSCH SWITCH MECHANI SM Filed Feb. 25, 1935 3 SheeLs-Sheeil l INVENTOR. HANS SE NGEBUSCH Aug. 25, 1936. ||l SErqGf-:BLJSCl-iv 2,052,059

' SWITCH MECHANISM Filed Feb. 25, 1935 3 Sheets- Sheet 2 ,33 94 ,l- 3o a2 Ff L/es INVENTOR. HANS SE NGEBUSCH ATTORNEY.

Aug. 25, 1936. H. SENGEBUSCH SWITCH MECHANISM Filed Feb. 25, 1955 3 Sheets-Shee'Il 3 FIG. I4

FIG. I3

FIG. 8

,H W. TS N NU R EB O VE u mm A E HANS s BY Patented Aug. 25, 1936 UNITED STATES PATENT OFFICE SWITCH MECHANISM Application February 25, 1935, Serial No. 7,983

17 Claims.

The present invention relates in general to automatic switching apparatus, but is particularly concerned with the production of an improved switch of the dat type in which the wipers are moved in one plane in two directions at right angles to each other.

The main object of the present invention is to provide automatic switches of simple structure, which are rapid and accurate in operation and which take up only a small amount of mounting space as compared with the present day automatic equipment.

Another object of the invention is to provide improved switchbanks which are easily assembled, cheaper in construction, and reliable for use with switches of this type.

One of the features of the invention relates to a spring driven escapement mechanism controlled by a single spring and a single operating 20: magnet for moving the wipers in both its selecting movements in the same plane.

Another feature relates to the changeover mechanism for changing the direction of travel of the wipers.

A further feature relates to the mechanism by means of which a single release magnet automatically restores the wipers back to their normal positions thereby tensioning the operating spring.

Other objects and features will be evident and a'complete understanding of the construction and operation may be had from a perusal of the description in conjunction with the accompanying drawings, in which:

Fig. 1 is a perspective view showing the main part of the switch with certain details and spring assemblies omitted.

Fig. 2 shows two slightly different cross sections n in part to more readily show the construction ofthe switch, the switchbanks and the mountingV arrangement.

Fig. 3 shows a detail view of the spring assemfl blies operated by the changeover and release magnets.

Fig. 4 shows a detail view of the escapement controlling mechanism and the spring assembly operated by the operating magnet.

Fig. 5 shows a detail view of the wiper guard for preventing vibration of the wipers.

Fig. 6 shows a detail view of the changeover magnet and mechanism.

Fig. 7 shows the ol normal spring assembly controlled by the escapement carriage.

8 shows the ,scam vspring assembly. which:

is operated by armature 93 when the wipers are operated to a point beyond the bank contacts.

Fig. 9 shows a cross section of one of the bank contact strips.

Fig. l0 shows a plan view of one of the bank 5 strips.

Fig. 11 shows a front view of the mounting arrangement for mounting the bank strips shown in Figs. 9 and 10.

Fig. 12 shows a side view of the mounting ar- 10 rangement.

Figs. 13 to 16, inclusive, show a modified bank structure.

Fig. 13 shows an end assembly View.

Fig. 14 shows a top View. 15

Fig. 15 shows a perspective of part of the bank assembly.

Fig. 16 shows in part a side view.

Referring now in detail to Figs. 1 and 2 the s switch mechanism is supported on a flat base 20 plate and two end brackets 2 and 3 which are rigidly secured to the base plate Rods 4 and 5 extend between the two end brackets 2 and 3 and are rigidly secured thereto. Slidably mounted on the rods 4 and 5 are the main carriage 6 and the 25 escapement carriage 7. Main carriage 6 comprises a metal plate provided with turned down edges, such asl 40, having bushed holes therein through which the rod 4 extends. On the uppermost portion of the main carriage 6 is pro- 30 vided a turned up edge 42 and a flat portion upon which the guide plates and 36 are mounted.

The edge 42 and the assembled guide plates 35v and 36 act as guides for the wiper carriage 8 which is slidably mounted on carriage 6. The left-hand 35 portion of carriage 6 is a recessed portion 43 in which a pinion 30 is rotatably mounted on shaft 3| secured to the carriage 6. The lower portion of carriage 6, or the left-hand portion as shown in the lower section of Fig. 2, is slightly bent so 40 that it rests on top of the rod 5. A bracket 44 secured to the lower portion of carriage 6 is arranged to engage the rod 5 on the opposite side from the carriage 6 so as to form a guide to permit movement of the carriage 6 on rod 5 in a 45 horizontal direction. The right-hand portion of carriage 6 is provided with turned down portions 4| and 40 in order to provide a mounting space for the changeover mechanism or locking dog which is rotatably mounted on rod 5| which extends through the turned down portions 40 and 4|. A leaf spring 90 secured to carriage 6 normally maintains the locking dog 50 in the position shown in Figs. 1 and 6. 55

The wiper carriage 8 is slidably mounted on main carriage 6 and has teeth on its left-hand edge which mesh with the pinion 39. A pin 29 mounted on the wiper carriage 8 rests against the top plate 32 and is provided to engage and operate armature 93 when the wipers are extended beyond the bank contacts. The top plate 32 is secured to the main carriage 6 in the manner shown in Fig. l and is provided with two po- inters 33 and 34 which point to numerals on the bar 94 and escapement carriage 'I to indicate the position the wipers are operated to. plate 32 is also provided with a hole in which the rod 3| extends. As will be seen from the drawings plate 32, guide plates 35 and 36 and the upturned edge 42 guides the wiper carriage in its lateral, or forward, movement whenthe pinion 30 is rotated. The upper portion vof wiper carriage 8 is secured to the bracket 83 which carries the wipers I6 to 8I, inclusive.

The escapement carriage 'I is made oftwo pieces of Isheetmetal, the piece 9 being secured to the piece 'I in any suitable manner. The piece 9 has a hard rubber bushing at its left-hand end for f riage ,'I have bent down portions 23 provided with bushed holes to permit carriage l' to slide on rod 5.- The left-hand end YZIio-carriage I extends in a forward direction where a slotted or U- shaped portion extends over the rod 4 to act as a guide for the carriage. Thefront portion of c'ar- Aresting on after the same have been moved. A

rage 6 willrmove horizontally with the escapepivotally connected to the spring actuated arm riage l is bent down in an L-shape as shown in Fig. 2 to form a rest for the toothed piece 9 which is riveted,ior otherwise secured, to carriage '1. .The bent down vertical portion has numbers thereon for indicating the lateral or forward movement of the wipers. The arm 94 likewise has numbers thereon for indicating the horizontal, or longitudinal, movement of thewipers. Both sets of numbers together with the pointers 33 and 34 indicate the set of bank contacts the wipers are hole 39 near'the right-hand end of carriage I is provided to allow the catch 52 of the locking dog 50 to drop Vinto and lock the main carriage 5 to the escapement carriage 'I so that the main carment carriage 'I. 'Y The left end piece 25 of the escapement carriage 'I also has a turned edge, shown more clearly1in Fig. 2, to which the link 85'is-pivotallyconnected. The link 35 is also 86 which is pivoted at 88 `to the base plate I. The spring 89 at one end is fastened to arm 85 at 87, and at the other end is fastened to base plate I. Spring 89 is normally tensioned to move the. escapement carriage to the right as seen in Fig. l. A spring and armature mounting plate 92 is secured to the end bracket 3r and is provided with turned edges to provide mounting space for Varmature 93 which is pivotally connected thereto.

The off-normal spring assembly III (Fig. 7) is also mounted on this plate. The upper portion of end bracket 2 is turned to the left, as seen in Fig. l, to forma mounting space for mounting the combedV locking plate and the back stop 46. Thecombed locking plate 55 has notches in its forward edge'in which the upturned lug 53 of locking dog 59 may be'positioned in order to lock themain carriage tothe switch frame when the locking dog 59 is operated from its normal The top position. As long as the locking dog 59 is in its normal position the lug 53 passes underneath the combed locking plate 45 when the carriages I and 5 are moved to the right. When the armature 55 of the changeover magnet 5l is operated, the 5 locking dog is operated to disengagelug 52 from the hole 39 in carriage 'I thereby unlocking carriage 'I from carriage 5 and the lug 53 is projected into one'of the notches in loclfning plate 45 dependent upon the initial movement of the carriages to the right. The lug 53 in engagement with one of the notches in the combed plate I5 locks carriage E to the switch frame to prevent further movement of carriage 5 when the escapement carriage is again moved. Lug 53 is -maintained in its locking position after deenergization of the changeover magnet 5l by the lug 52 riding on top of carriage ll. Back stop 53 has a turned down end which engages and limits the back stop of the release magnet armature 55.

The iron core II of operating magnet III is secured to the base plate I by means of brass lug 98 and brass machine screws. A portion of the base plate I directly below the iron core II is cut outto reduce or prevent flow of magnetic flux in the base plate I.

Heel piece I2 of magnet I9 is formed of magnetic iron in the' shape of a letter L and is fastened at its upper end to core II and near its lower end is fastened to the base plate I by means of brass screws and a brass lug (not shown). Armature I3 is pivotally mounted to the base plate Irin close proximity to the heel piece I2 so that the magnetic flux set up in the core II will extend from the core II throughthe heel piece I2 and armature I3 back to core II. Armature I3 has two turned ears I4 through which the rod I5 extends for pivotallyrmounting armature I3 to base plate I. Arm I8 on armature I3 extends at right angles from the main body of armature I3 and'is provided with a hard rubber bushing for operating the spring assembly H9 whenever the armature is attracted by magnet I9. Lug I9 on armature I3 is also bent at right-angles to the main body of armature I3 and is provided to engage and operate the bent portion 2| of pawl 23 when the armature I3 is actuated. The end portion or detent 29 of armature I3 is bent in the manner shown to limit the movement of the escapement carriage I to one step when armature I3 and lug I9 has rotated the pawls 23 and 68 from in engagement with the teeth 33 of escapement carriage I. The pawl 23 is pivoted on rod 22 and is normally held in engagement with teeth 33 by spring 24 except when armature I3 is actuated. 'A lug Il in base plate I acts as a back stop for armature I3 while spring I5 secured to armature I3 normally holds the armature against lug Il except when magnet I is energized.

The U-shaped iron core of changeover magnet I0 is secured to base plate I by means of brass screws and brass lugs 55' as shown in Fig. 6. Base plate I also has a cutout portion paralleling the iron Vcore 55 to restrict or prevent the flow of magnet flux in base plate I. Armature plate 56 65 is formed of a flat piece of magnetic iron and hasv two lugs on its lower edge which extend through holes in base plate I. Two holes lin these lugs are provided to allow the longitudinal portions of spring 56 together with the vertical 70 portion of spring 56 to hold the armature plate 56 in the position shown. The locking dog 50 has a curved portion 54 which by means of spring 90 normally holds armature 56 a short distance away from the core or pole piece 55. When the 'now be given. The switch as ShQWIl,-in Fig. 1 is changeover magnet 51 is energized armature 56 is attracted to pole piece 55 thereby rocking locking dog 50 onV itspivot 5|v against the" tension of' spring 90 to remove lug 52 from the hole 39 in carriage 1 and to project the lug 53 in one of the` notches of combed plate to lock carriag'ef 6 to the switch frame. The operation` of armature plate 56 also rotates the armature 58 `on itsv pivot 59 secured to base plate I. Armature 58 has a hard rubber bushing on its right-handarrn; for operating spring assembly I 09` whenever ar'^ mature plate 56 is attracted. The middle spring of assembly |09 helps to retain armature plate 56 in its normal position. The spring assembly is mounted on base plate I in the manner shown 1n Fig. 3. Y-

Heel-piece 62 of release magnet 6| is fastened; tothe left-hand pole piece and to the b ase platein a manner somewhat similar to that described for magnet I 0. Armature mounting plate 64 --is secured to heel piece 62 and is provided with bent ears to which armature 66 is rotatably fastened.

ture 66 at 10. A spring 1| havingone end fas-- tened to armature 66 and the other end fastened to the turned up -portion v12 of pawl 68 normally holds the bent left-hand portion 68 against teethy 36. Lug 13 in plate I is provided to limit the stroke of pawl 68 when magnet 6| is actuated. As `previously stated whenever armature I3 or magnet I0 is attracted the lug I9 rotates the pawl 23 from engagement with teeth 38.v This same rotation of pawl 23 also moves pawl68 from engagement with teeth 30 to permitcarriage 1-` to move one step or until the detent 20 of armature I3 limits its further movement.

The fork shaped member I 04 is secured to car-` rlage 6 as shown in Fig. 5 and has arms |05-, 06, and |01 on their upper ends to maintainthe wipers, separated and to prevent such wipers vibrating when the wipers are moved.

The female jack assembly 9| is mounted on base plate I near the rear of the switchfas shown in Fig. l. on the upright 95. The bank contact assembly, such as shown in Figs. 13 to 16, inclusive, are shown in Fig, 2 in order to show the relative position of the switch wipers Aand .the bank contacts, such bank contact strips being mounted on the uprights 95 in any suitable mannen- In order to mount 'the switch the same is pushed in on two angle irons 99 on side uprights-91- untilthe Jack assemblies mesh and until baseplate I has been pushed to its proper position in which posi. tion said base plate is locked by alug (not shown)- on the angle irons Y9.9.

Abrief description ofthe switch operation will in normal position with the operating spring 89 tensioned. Whenoperating magnet I0 actuates its armature I3 to operate the-escapement mech-Y anism, pawl 23 and pawl 68' are vdisengaged from teeth 36. The. escapement. carriage 1 is` then moved by spring 89 to the right one step vuntil detent 20 yof armature I3 engages one of the teeth 38. Since carriage 6 is locked to carriage 1 both carriages are therefore moved to the right The male jack assembly 96 is mounted' one step. The wiper carriage 8 is moved to the right with carriage 6. When armature I3 restores,- spring 24 rotates the pawl 23 and spring 1| rotates the pawl 68 to engage teeth 38 of the escapement carriage. Subsequent operations of armature I3 move all the carriages to the right as just described to cause the wipers on the wiper carriage to be positioned opposite a desired set of bank contact strips. When the changeover mag-net- 51 is operated locking dog 50 at lug 52 unlocks carriage 6from carriage 1 and at lug 53 locks carriage 6 to the switch frame to prevent further movement of carriage 6 to the right. Now when operating magnet I0 again operates the escapement mechanism, spring 89 again moves escapement carriage 1 to the right. Since the main carriage 6 is locked against movement, the teeth on the upper edge of escapement carriage 1 rotates pinion 30. The rotation of pinion 30 now moves the wiper carriage 8 in a forward or lateral movement to cause the wipers to successively engage the contacts of the selected bank strips and to stop on a certain set of contacts dependent upon the number of actuations of magnet I0. If for any reason the wipers are moved ybeyond the last contact set in their lateral movements, then pin 29 on carriage 8`strikes bar 93 of armature 93 to actuate said armature and spring assembly ||2 which closes circuits (not shown) to restore the wipers to their normal position. In addition the first step of escapement carriage 1 to the right removes the rubber bushing on bar 9 of the escapement carriage from engagement with the off normal spring assembly I I I thereby causing the operations of such springs to their alternate positions. The operation of the magnet I0 also operates spring assembly ||0 and the operation of changeover magnet also operates spring assembly I 09.

In Aorder to restore the switch wipers and carriages to normal release magnet 6| is intermittently operated to actuate armature 66. Each actuation of armature 66 operates pawl 63 to move the carriage 1 back one step to the left and also operates interruptor springs 63. Since carriage 6 is still locked to the switch frame, the movement of carriage 1 to the left rotates pinion 30` to cause the wiper carriage 8 to slide on carriage 6 luntil such time as pin 29 strikes plate 32. At this time lug 52, which has been riding on top of carriage 1, now drops into hole 39 in carriage 1 to cause lug 53 to unlock carriage 6 from. the switch frame and to lock carriage 6 to the escapement carriage 1 so that all of the carriages are returned to the left in vresponse to the continuedoperations of release magnet 6|. When all of the carriages are restored to their normal positions the off-normal springs II I are operated to prevent further actuations of release magnet 6|. From the foregoing it will therefore be seen that the wipers of the switch are rst moved step by step in a horizontal or longitudinal direction to select a set of bank contact strips, or a group of lines, and are thereafter moved step by step in a forward or lateral direction to select a set of contacts on-the selected strips, or a line in the selected group.

g Referring now to Figs. 9 and 10, beveled metal contact strips I2I are placed on both sides of sheets |20 of uncured-bakelite in the proper locations in the form or mould and then subjected to the usual pressure and heat treatment to form the bank contact strips sho-wn in Figs. 9 and 10. Figs. -11- and l2 show how these bank strips are mounted in the plates |23 which are provided "the base plate with notches |24 in which theY bank strips" are placed. 'I'he plates V|23 are secured to channel irons |22 by means of machine screws as shown. The notches |24 facilitate the ease with which the bank strips can be assembled and replaced. Such bank strips may b-e made of any reasonable length to provide the usual bank contacts forV a plurality of switches. vIn bank s tripsof this type the usual multiple wiring between the bank contacts of adjacent switch banks such as is used in the well known Strowger systems, is eliminated. 'i e Y Figs. 13 to 16, inclusive, show a somewhat sim ilar bank arrangement, the method of assembling and the construction, however, being differ-ent. The bank strips for a plurality of switches are assembled in the following manner: The at metal base plate |28A extends the width and length of the entire contact assembly. Base plate y|2|3 is `provided. with 'holes through which the bolts, such as |21, extend to clamp the Contact strips together. A row of separator insulators, such as |29, are next assembledon the bolts |21. Ten metal contact strips,'such as |33, properly spaced are now placed on the insulators |29. A

large insulating plate ISI somewhat similar in shape to base plate |25 but having cut-out portions, as shown in Fig. 15, for permitting longitudinal movement of the switch wipers, is next assembled with the holes |28 guiding the plate |3| over the bolts |21 to the position shown in Fig. 15. Another set of contact strips |36 are then placed on thisrinsulating platev |3| followed by a row of separator insulators |29 after whichv :another set `of contact strips |39, another insulating plate |3|, a further set of contact strips I3@ and another row of separator insulators |29 are assembled in the order named. The entire bank assembly is built up in this'manner Auntil the required number of bank contact strips are assembled. After the last row of separator insulators |29 are in place'a metal plate |32 is placed on top of each insulator |29 and the bolts |21 are securely tightened. By referring to Fig. 16 it will be seen that the bank strips |3 are assembled on both sides of insulating plates |3| and that a space is left between adjacent sets of bank Contact strips through which the wipersY of the switch may be advanced in a lateral manner to engage successive bank contact strips. Due to |26 and the different sections clamped by bolts |21, the entire bank assembly is Yrigid in construction and is easily mounted on uprights for cooperation with the wipers of a number of Yswitches as shown in Fig. 2.

Having described the invention,'what is considered to be new and is desired to be protected by Letters Patent will be set forth in the following claims.

What is claimed is:

.1.y In an automatic switch, an escapement carrage, a single spring'for supplying the motive power to move said'rescapement carriage, an escapement mechanismfor controlling the operation. of said escapement carriage, a'magnet for operating said escapement mechanism to permit said spring to operate said escapement carriage, a wiper carriage moved in one direction in response to the Vfirst movements of said escapement carriage, andV a pinion having teeth in mesh with teeth on said escapement carriage and with teeth on said'wiper carriage for moving said wiper carriage in another directicnrin response to subsequent movements of said escapement car- 2. In an automatic switch,v anuescape'ment ca rY-V:

rage, a single spring for supplying` themotive power to move said escapement carriage, an escapement mechanism for controlling the operation of said escapement carriage, a niagnretfforA operating said escapement mechanism to permit said springrto operate said escapement carriage;VV a Wiper carriage moved in one directicnin re.-

sponse to the rst movements of said escapement carriage, a pinion having teethv in mesh with teeth on said escapement carriage-and with teeth on said wiper carriage for moving said wiperI carriage in another direction in response to sub-I sequent movements of said escapement carriage, and means for renderingsaid pinion ineifective to move said wiper carriage on the rst movement ofv said escapement carriage and for rendering said pinion effective to move the wiper carriage only after the rst movements of Ysaid escapement carriage.

3. vIn an automatic switch, an

power to move said escapement carriage, anescap'ement mechanism lfor controlling the operation of said escapement carriage, a magnet for operating said escapement mechanism topermit"` said spring to operate said escapement carriage, a

wiper carriage moved in one direction in response. to the rst movements of said escapement car-- riage, a pinion having teeth in meshY with teeth on said escapement carriage and with teeth on said wiper carriage for moving said-wiper carf, riage in another direction in lresponse to subsequent movements of said escapement carriage, and indicating means for indicating both movements of said wiper carriage. .n Y Y:

4. in an automatic switch,ra `switch fr me, av main carriage slidable on said frame,` a wiper.

carriage slidable on said main carriage, an`es vfor locking said main carriage` to said switch,

frame to prevent,furthermovement thereof, said magnet thereafter V,operating said escapement mechanism to permit said springvto again move said escapement carriage in the same direction whereby the teeth onusaid escapement carriage rotate said pinion to move said wiper carriage in a different direction. .7 Y.

5. In an automatic switch, a switchframe, a, main carriage, a wiper carriage, anescapement carriage, locking means. normally lockingsaid main carriage to said escapementcarriage, an operating spring normally tensioned to move said escapement carriage, escapement mechanism'normally holding said escapement carriage from movement, a magnet for operating said escape-' ment mechanism to first permit said spring to move all said carriages in one direction, means for thereafter operating said,lockingV means to unlock said main' carriage from said escapement carriage and to lock said main carriageto' said switch frame, said magnet thereafter operating Y escapement car-1 rage, a single spring for supplying .the motive,l

said escapement mechanism to permit said spring to again move said escapement carriage, means including a pinion rotated in response to the last movement of said escapement carriage for moving said Wiper carriage in a different direction, means for restoring said escapement carriage to its normal position and for retensioning said spring, the first part of the restoration of said escapement carriage rotating said pinion to restore the wiper carriage from its last operated position, said locking means being returned to its normal position when the wiper carriage is restored to unlock the main carriage from the switch frame and to lock the main carriage to the escapement carriage, and the second part of the restoration of said escapement carriage thereafter causing all said carriages to be returned to their normal positions.

6. In an automatic switch, a switch frame, a main carriage slidably mounted on said switch frame, a wiper carriage slidably mounted on said main carriage, an escapement carriage slidably mounted on said switch frame, locking means normally locking said main carriage to said escapement carriage, means for operating said locking means to unlock said main carriage from said escapement carriage and for locking said main carriage to said switch frame, means including a magnet, an operating spring and an escapement mechanism for operating said escapement carriage, and means responsive to the operation of said escapement carriage for moving `said wiper carriage and the main carriage in one direction in case said locking means is in normal position and for moving said wiper carriage in another direction in case said locking means is in its operated position.

- 7. In an automatic switch, a switch frame, a main carriage slidable on said frame, a wiper carriage slidable on said main carriage, an escapement carriage slidable on said frame, locking means normally locking said escapement carriage to said main carriage, means including a magnet, an operating spring and an escapement mechanism cooperating with said escapement carriage for moving said escapement carriage and said main carriage with its associated wiper carriage in response to the rst operations of said magnet, a changeover magnet, means operated by said changeover magnet for operating said locking means to unlock said main carriage from said escapement carriage and to lock said main carriage to said frame, and means including said first magnet, said operating spring and said escapement mechanism for thereafter moving only said escapement carriage and said wiper carriage in response to the second operations of said rst magnet.

8. In an automatic switch having a wiper carriage adapted to move in straight line motions in aA plurality of directions in one plane to make a selection, a single escapement spring means for moving said carriage in both directions, a single operating magnet, means responsive to the iirst plurality of operations of said magnet for operating said escapement spring means to move said wiper carriage in one of its directions, and means responsive to a second plurality of operations of said magnet for operating said escapement spring means to move said wiper carriage in its other direction.

9. In a switch mechanism of the type wherein a carriage is first moved longitudinally and then laterally in the same plane to selectively position wipers carried by said carriage; the provision of a single operating spring and a single step-by-step means for controlling the positioning of said wipers, and another single step-by-step means for restoring said wipers and retensioning said operating spring.

10. In a switch mechanism of the type wherein a carriage is rst moved longitudinally and then laterally in the same plane to selectively position wipers carried by said carriage; the provision of a single operating spring and a single step-bystep means for controlling the positioning of said wipers, a changeover magnet for changing the direction of travel of said carriage and wipers,

and another single step-by-step means for restoring said wipers and retensioning said operating spring.

1l. In a selecting switch, xed contacts, contacts movable for engagement with said xed contacts, an element carrying said movable contacts mounted for movement in two diiierent directions in the same plane, a spring for operating the movable contact carrying element in its two directions to make a selection of said xed contacts, and an escapement magnet intermittently operated during both movements of said element to control said element in its two directions of travel.

12. In a selecting switch, iixed contacts, contacts movable for engagement with said iixed contacts, an element carrying said movable contacts mounted for movement in two different directions in the same plane, a spring for operating the movable contact carrying element in its two directions to make a. selection of said xed contacts, an escapement magnet intermittently operated during both movements of said element to cause said element to move step-by-step in its two directions of travel, and a changeover magnet for changing the direction of travel of said element.

13. In the bank contacts for a plurality of switches, a plurality of unit bank assemblies, each such unit comprising in combination a iirst series of parallel bank contact strips, a second series of parallel bank contact strips, and a single insulator extending parallel with said series of contact strips for separating said two series of strips, each series acting as bank contacts for a plurality of switches and as the multiple therebetween, rows of insulators separating each unit bank assembly from another and for enabling switch wipers to pass between such units, and means for rigidly holding said units and insulators together to form a series of bank contacts accessible to a plurality of switches.

14. In a telephone system, a plurality of switches, a single bank assembly for all said switches comprising a plurality of unit bank assemblies, each such unit comprising in combination a first series of parallel bank contact strips, a second series of parallel bank contact strips, and a single parallel insulator separating said two series of contact strips, each series of strips accessible to the wipers of a plurality of switches, and assembling means for separating each of said units to enable the switch wipers of all said switches to pass between adjacent units.

l5. A bare wire bank multiple unit comprising a plurality of unit bank contact assemblies each unit bank contact assembly comprising a strip of insulating material having a series of parallel contact strips on either side thereof, and means for separately mounting each unit with suiiicient space between adjacent units to permit the passage of switch wipers, said last means spacing off lsections ofvsaid contact strips as contact banks and covering sections thereof as multiple connections.

16. In combination in a bare wire bank multiple, a plurality of unit bank contact assemblies, each unit bank contact assembly comprising a runit strip of insulating material having a rst series of parallel bank Contact strips imbedded on one side of the unit strip and a second series of parallel bank contact strips embedded in the wether side of the unit strip, each contact strip having sections acting as contacts for a plurality of switches and other sections acting as a multi- Vple between contacts, and Supporting means having notches therein for holding and spacing said unit strips with suiicient space between adjacent unit strips-to permit passage of switch wipers.

17. A bare wire bank multiple for a plurality of switches, comprising a plurality of strips of inSulating material each having a plurality of Contact

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