US1125682A - Selector-switch. - Google Patents

Description

0. F. PORSBERG.

SELECTOR SWITCH.

APPLICATION FILED JAN.13,1913.

1,125,682. Patented Jan. 19, 1915.

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//7 van/0r. Oscar F Farsberg.

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O. F. FORSBBRG.

SELECTOR SWITCH.

APPLICATION FILED JAN.13,1913.

1,125,682. Patented Jan. 19, 1915.

4 SHEETS-SHEET Z.

//7\/e/7/0/.' Oscar f. Fomberq.

Wf/H ewes O. F. FORSBERG.

SELECTOR SWITCH.

APPLICATION FILED JAN.13,1913.

Patented Jan. 19, 1915.

4 SHEETSz-SHEET 3.

/\/em0/ Oscar Farsberq.

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NORRIS PETERS c0 4 FHOTG u 0. F. FORSBERG.

SELECTOR SWITCH.

APPLICATION FILED JAN.13,1918. 1,125,682. Patented Jan. 19, 1915.

4 SHEETSSHEBT 4,

TED srarnsrarnn'r OFFICE.

OSCAR F. FORSBERG, OF YONKERS, NEW YORK, ASSIGNOR TO WESTERN ELECTRIC COlVIPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

SELECTOR-SWITCH.

To all whom it may concern:

Be it known that I, OSCAR F. Fonsnnno, a citizen of the United States, residing at Yonkers, in the county of Westchester and State of New York, have invented a certain new and useful Improvement in Selector-Switches, of which the following is a full, clear, concise, and exact description. 0

This invention relates to automatic switches of the rotary type such as are particularly useful in telephone exchange systems.

The object of this invention is to improve the construction and arrangement of the parts of the switch mechanism whereby the interconnection of lines may be effected with greater rapidity and precision.

One feature of this invention relates to the movable brush structure and the means for controlling the activity of the several brush sets.

Another feature resides in the improved manner of mounting the stationary terminal blocks in the frame.

Another feature relates to the improved means for extending the telephone circuits to the brushes and to the interrupter device.

A further feature resides in the improved manner of assembling the frame members of the switch mechanism.

In this switch a plurality of sets or normally inactive movable terminals or brushes are provided for connection with the stationary terminals. These brushes are retained in their inactive or retracted position until they are released by the operation of the brush selecting means. They are preferably arranged in alinement upon a rotary carriage and held in their retracted position by a plurality of cams, any desired one of which may be rotated by the brush selecting device to permit the release of the corresponding set of brushes. The coiiperating terminals are held stationary and are arranged in semi-circular rows, transverse to the row of brushes, in such a manner that the movable terminals will traverse their respective rows of stationary terminals on rotation of the carriage. The brush selecting means is adapted to effectively engage one and only one of the brush cams during the initial movement of the carriage from its normal position.

The brushes are arranged in sets of three each, each set being held retracted by a sin- Specification of Letters Patent.

Patented J an. 19, 1915.

Serial No. 741,864.

gle cam and the corresponding brushes of the several sets are joined electrically in multiply connected groups. In the structure here shown this multiple arrangement is secured by forming the correspondin brushes of the several sets as the teeth of metallic combs. These combs are so formed that the space of two brushes is provided between each tooth and the next adjacent one, and the teeth of the three combs are arranged in staggered relation so as to cause the teeth of the first comb to engage the contacts of the first, fourth, seventh, etc. rows of stationary terminals, the teeth of the second comb to engage the contacts of the second, fifth and eighth rows of stationary terminals, and the teeth of the third comb to engage the contacts of the third, sixth and ninth rows of stationary terminals, and so on.

The rotary movement of the brush carriage and also of the brush selecting device is effected by means of electromagnetic clutches. Each of these clutches has a mem ber arranged onthe same power shaft. This power shaft may be rotated continuously or intermittently as desired. In the operation of my invention the brush selector is first rotated to a position to subsequently engage a particular one of the brush cams; then the operating shaft is connected to the brush carriage to advance the same, and in its initial movement the cam of the selected set is rotated by engagement with a lug projecting from the brush selector. The rotary movement of the carriage is then continued to cause the particular set of brushes to traverse their respective rows of stationary terminals until the terminals of the desired line are reached. The brush selector by means of which the desired set of brushes is released, comprises a shaft having a plurality of outwardly extending fingers spirally arranged thereon, one finger or trip lug being provided for each set of brushes and in such a position that when said brush selecting device is rotated to a particular position, one of said fingers and only one will engage its respective brush cam. The rotation of this shaft, as previously stated, is caused by an electromagnetic clutch which effectively associates it with the rotating power shaft.

The selected brushes-are restored to their normal or retracted position by a yokeshaped lever rotatably mounted on the switch carriage, which upon the return of the carriage to its normal position engages a cooperating stationary element in such a manner that the actuated cam will be engaged and rotated to its normal position, thus retracting or restoring the released brushes. The return to normal of the switch carriage is accomplished by continuing the rotation of the brush carriage, in the same direction as in its advance, to trail the brushes over the terminals until one complete revolution has been made. The general arrangement is, therefore, one in which the brush selector is set into position to release a set of brushes, after which the brush carriage is moved first into operative relation with the brush selector, then over the rows of stationary terminals, until the desired terminal is reached, then upon disconnecticn the rotation is continued to effect the actuation of the restoring device, and finally back to normal.

The brush carriage as a. whole possesses considerable inertia or momentum and as it is desirable to move the same at high speed in making the connection between the brushes and the stationary terminals, and also in returning the brush carriage to its normal position, a device is therefore provided for stopping the brush carriage quickly when the driving mechanism is disconnected therefrom. This device, as herein shown, is in the form of an electromagnet which is adapted to be energized simultaneously with the disengagement of the driving mechanism. Upon energization of this stop magnet a part of the carriage is drawn into frictional contact with a portion of the electromagnet, such as its core,

thus arresting its movement.

For a more complete description of my invention, reference is now made to the accompanying drawings in which,

Figure 1 is a front elevation of the switching device; Fig. :2 is a plan view of the same; Fig. 3 is a section on the line 33 of Fig. 1 showing one of the brush cams in its tripped position; Fig. 4 is a similar view showing the brush restoring device in operative position; Fig. 5 is a View of one of the brush cams detached; Fig. 6is a plan view of a portion of the stationary terminals showing a spacing lug forming one of the features of this invention; Fig. 7 is a perspective View of a portion of the stationary terminal set and the framework thereof, showing the means for holding the terminal blocks in position; Fig. 8 is an end view of the stationary terminal bank Fig. 9 is a view showing the manner of mounting the frame members of the switch; Fig. 10 is a sectional view on the line 1010 of Fig. 9; Fig. 11 is a side View of the upper end of the'carriage shaft showing the circuit coming the rotation of the brush carriage and I the other for causing the rotation of the brush selector.

The stationary terminals 8 are secured in terminal blocks 9 of hard rubber or other insulating material, there being a single row of terminals in each block. These blocks are vertically arranged between the upper and lower arcuate supporting members 10 and 11 so that the terminals 8 will occupy a substantially radial position. Each of the terminal blocks is provided at each end with a pair of depressions 12 and each of the arcuate members 10 and 11 are provided with corresponding pairs of lugs 13 adapted to be positioned in the de ressions when. the bank is assembled, whereby the terminal blocks may be rigidly retained in position. The lugs 13 are formed by extruding the metal from the plates as shown most clearly in Fig. 7. The arcuate supporting members 10 and 11 are secured at .ach end to the upper and lower ends, respectively, of the Vertical members 14, by the screws 15, thus clamping the terminal blocks 9 between their supporting plates.

Each of the vertical members 1a is provided with wo integral screw threaded lugs 16, see Figs. 6 to 10. Openings 17 in the uprights 18 are arranged to receive these lugs, the vertical members 14 being secured to said uprights by the screws 19. The shouldered outer ends of the lugs 16 are arranged to fit in depressions 20 formed in the vertical side members of the frame 1 and are secured therein by the screws 21, as shown in Fig. 10. This assures that the shaft 22 of the switch carriage will occupy a definite relative position in regard to the stationary terminal bank notwithstanding variations in the thickness of the uprights 18. Thus it will be seen that the stationary terminals are secured to the frame and are arranged so that their inner ends are disposed about a semi-cylindrical surface and form horizontally curved rows and intercepting vertical rows. The rearwardly projecting ends of the terminals form soldering clips to which the circuit wires may be connected. The brush carriage 2 comprises the shaft 22 nearthe upper and lower ends of which are secured the triangular frame members 23 and 24. At the outer ends of these frame members and extending vertically between them is a bar 25 to which are insulatively secured the backs of the comb punchings 26, 27, 28 respectively, the teeth 29 of which are bent at the outer ends to form the brushes 30. Also between the outer ends of these frame members and parallel to the bar 25 but spaced therefrom is a pivot rod 31 upon which are mounted the several brush controlling cams 32. This pin also forms a pivotal mounting for the brush restoring yoke or lever 3. The teeth of the brush combs are so formed that their resiliency tends to thrust the brushes outwardly, this outward movement being normally restrained by the action of the brush cams but upon rotation of the cams the teeth of the combs are allowed to move outwardly, as shown in dotted lines in Fig. 4, so that the angularly extending surfaces at the ends thereof may trail over their respective rows of stationary terminals. The restoring member which, as before stated, is mounted on the pivot rod 31 with the brush cams, is made in the form of a yoke as shown most clearly in Fig. 1, and is so placed that the vertically extending portion 33 thereof is adjacent to the outwardly extending levers 34 on the several brush cams. At the lower end thereof and integral therewith is a lateral extension or lever 35. Upon the operation of one of the brush cams to release a set of brushes, the restoring device 3 is rotated and the lever 35 is caused to assume a radial position with respect to shaft 22, as shown in Fig. 3. When the carriage returns to normal, the travel of this lever is intercepted by the restoring roller 36 secured to the lower part of the frame and the restoring member is rotated carrying with it the brush cam of the released set, thus insuring that all the brush sets will be in their normal positions ready for another selecting operation. The advantage of this arrangement is that only sufficient force to retract the brushes actually released need be expended.

Secured at the upper end of the bar 25 is an interrupter device comprising a pair of flexible arms or levers 37 and 38. At the free end of the arm 37 is a roller 39 adapted when the brushes are moved over the stationary terminals to engage the teeth 40 and depressions 41 of the serrated edge of the semi-circular plate 10 which forms the upper supporting plate for the stationary terminal blocks 9. Insulatively mounted on the same bar 25 between the levers 37 and 38 is a pair of contact springs 42 and 43. Each of these levers carries at the outer end thereof a block of insulation 44. This prevents contact of the springs 42 and 43 with the levers 37 and 38, respectively. The arm 38 is provided at its outer end with a curved surface adapted to engage the upwardly extending smooth surface of the semi-cylindrical rim 45 mounted on the member 10 and substantially concentrically therewith.

In the normal position of the brush carriage the roller 39 of the arm 37 engages a cam plate 48 insulatively secured to the switch frame at one side thereof. This cam plate is shaped to form a depression 47 for the rolzer, in which said roller normally rests. The purpose of this arrangement wili be hereinafter disclosed. Nhen the brush carriage is rotated to trail the movable brushes over the stationary terminals, the arm 37 is rocked back and forth by the engagement of the roller 39 with the serrated edge of the plate 10, while the curved end of the lever 38 rides smoothly over the rim 45. This to and fro movement will be communicated to the springs 42 and 43 by blocks of insulation 44, thus causing the springs to make and break their contact. Vhen the roller 39 occupies a position in any of the depressions 41 of the plate 10, the contact between the springs 42- and 43 will be open. The movable terminals at this time will be in a position to engage a certain vertical row of stationary terminals.

When, however, the roller 39 is riding over the teeth 40 the contact springs 42 and 43 will be closed and the brushes will at this time be in transit between the rows of stationary terminals. Thus as the switch carriage is rotated to trail the brushes over the stationary terminals, the contact between springs 42 and 43 will be opened, once for each terminal traversed by the brushes, and will be closed while the brushes are traveling between successive terminals. The function of this switching device is to measure the movement of the brushes over the stationary terminals and by cooperation with suitable controlling or sending mechanism will cause the brush carriage to be stopped with the selected brushes in engement with the desired set of stationary terminals.

In order to provide for circuit connections to the combs 26., 27, 28 forming the movable brushes and. also to the springs 42 and 43 of interrupter, a set of collector rings 48 is mounted near the upper end of the shaft 22. The structure of this set of rings is clearly shown in Fig. 12 wherein it may be noted that the several contact rings 49 of this device are separated by perforated insulating disks 50. Each of the contact rings 49 is provided with a hollow proiection or thimble 51 having an opening at the tip thereof through which a conductor is adapted to project and in which. it may be secured by solder. These projections on the several disks are placed out of alinement and the circuit wires, respectively, individual thereto are threaded through openings in preceding disks as shown by dotted lines in said Fig. 12. These hollow projections also serve the additional function of preventing relative rotation of the rings 49 and the disks 50 of insulating material thereunder.

On the other side of each of the conductor rings 49 is a. similar projection 52 which,

-howe'ver, need not be hollow and which entering a perforation in the insulating disk on the opposite side of the ring 49 serves to hold the entire set in non-rotatable relation when mounted on the insulating sleeve through which passes the hollow bolt 54.

represents a screw-threaded washer adapted to engage the threads 56 on the bolt and by means of which the several disks are clamped between the head 57 of the bolt and said washer.

The upper end of the shaft 22 has a cylindrical projection 58 on which the hollow bolt 54 is placed, being retained thereon by the nut 59. The segmental projections 57 on the head of said bolt serves to prevent relative rotation of the shaft and bolt. The upper horizontal portion of the frame memher 1 is provided centrally thereof with an opening 60 through which extends the pivot pin 61, the shouldered end 62 of which is received by the upper end of the projection 58, thus providing a pivotal mounting for the upper end of the carriage shaft. The pivot pin 61 is held in the opening 60 of the frame by a set screw 68. \Vires 64 join each of the multiply connected sets of brushes to a soldering thimble on'its respective collector ring and Wires 65 similarly join the springs 42 and 43 to other collector rings.

Insulatively mounted on the frame and bearing against the collector rings, as shown in Fig. 11, is a group of brushes 100 to which the circuit wires may be connected.

The brush selector 5 comprises a shaft having a plurality of outwardly projecting fingers 6'7 spirally arranged about the surface thereof. There is one finger for each brush cam and these fingers are so arranged that only one of them can be placed in the path of travel of a brush cam at one time. Secured to the lower end of the shaft is a starwheel 68. Mounted on the frame in operative relation to the starwheel is a set of contact springs 69, and 71. The spring 69 is provided at the inner end thereof with a roller 72 adapted to ride over the serrations of the starwheel when the shaft is rotated, the roller 72 being held firmly against the starwheel by the resiliency of its supporting arm 69. One of the depressions in the starwheel is deeper than the others and in the normal position of the brush selector the. roller 7 2 rests in this depression. When the shaft is rotated away from its normal position, the arm 69 is lifted and rocked back and forth as the roller 72 engages the teeth and depressions of the starwheel 68. The contact springs 70 and 71 are engaged by the oscillating arm 69 in the movement of the shaft 66, contact being made continuously with the spring 70 and intermittently with the spring 71 when the shaft is away from normal position. The function of this switching device, comprising the movable arm 69 and the spring 71, is substantially the same as that of the interrupter or switching device which controls the movement of the hrnsh carriage; that is, the intermittent connection of spring 69 with spring 71 serves by cooperation with suitable controlling mechanism to measure the rotation of the brush selecting device and hence determines which of the several brush sets will be released. The function for the spring 70 will appear later.

Mounted at the top of the stationary terminal bank at one side thereof is a pair of spring 73, 74. The spring 74 has secured thereto inwardly extending arms 75 between which is mounted the roller 76. Upon the upper end of the brush carriage at the outer edge thereof is a cam member 77. This cam is adapted to engage the roller 76 when the carriage leaves its normal position to separate the springs 73 and 74 and hold them open until after the carriage has passed its brush selecting position. These springs are in the circuit of the clutch magnet 7 by means of which the brush selecting shaft is rotated. It will, therefore, be seen that movement of the brush selecting device is positively prevented during the brush selecting travel of the carriage.

Mounted on the stationary terminal bank adjacent to the springs 73 and 74, but insulated therefrom and from each other, is a pair of contact springs 78, 79. Between these springs is an insulating lug 80 carried by the lever 81 pivotally mounted at 82 on the plate 10.

Pivotally mounted at 83 at the center of the stationary terminal bank is a trip lever 84 having thereon a projecting catch 85 against which the rear end of the lever 81 is adapted to rest in such a position that the pressure of the lug 80 on the spring 78 will force it from contact with the spring 79. 'he stationary terminals are divided centrally into two sections or groups and upon the rotation of the carriage at the instant the brushes pass from one stationary terminal section to the other, the projecting lug 86 on the upper carriage frame member 24 is adapted to engage the projecting end of the lever 84, thus releasing the lever 81 to allow engagement of the springs 78 and 79. The purpose of these springs is to accompli sh certain circuit changes incident to the arrangement of the stationary terminals in two sections. Upon the return to normal of the switch mechanism, these springs are returned to their normal separated position by the engagement of the cam member 87 carried at the upper end of the brush selector shaft 66 with the roller 88 carried at the inner end of the lever 81. This causes the separation of the brushes and also forces the rear end of the lever 81 forwardly. A spring 89 serves to move the trip lever 84: to again position the catch 85 in the path of the inner end of the lever 81.

The electromagnetic switch 6 comprises a coil through the center of which a continuously rotating shaft 91 passes. A portion of this shaft forms the magnetic core of said coil. At one end of the coil 90 and fixed to the shaft 91 is an iron roller or disk 92. This disk rotates in close proximity to the under surface of an annular iron disk 93 flexibly secured to the shaft 8 by means of the radial metal fingers 94-. T he coil 90 is held stationary by extensions of the spool head being secured to the switch frame. WVhen current is passed through the coil 90, the disk 93 is drawn into engagement with the periphery of the friction disk or roller 92 and the brush carriage is caused to rotate. The electromagnetic clutch 7 is similar in construction to the one just described. It comprises a coil 95 rigidly secured to the frame below the selecting shaft 66. Above this coil and carried by the shaft 66 is a friction disk 96, and flexibly secured to the shaft 91 in proximity thereto is a disk 97 in all respects similar to the disk 93. lVhen current flows through the coil the disk 97 will be drawn into engagement with the friction disk 96 to rotate the brush selecting shaft. A pair of electromagnets 98 is provided for the purpose of quickly stopping the movement of the carriage when the power is disengaged therefrom. These electromagnets have pole pieces 99 projecting in proximity to the disk 93 of the brush carriage. lVhen current is directed through the windings of these electromagnets, the disk 93 will be forcibly drawn into frictional engagement with the pole pieces 99 to quickly stop the carriage.

The operation of the switch mechanism above described is as follows: Current being directed through the coil 95 of the clutch magnet 7. the disk 97 secured to the powe shaft is drawn into engagement with the roller 96 upon the brush selecting shaft and causes the said shaft to be rotated. The fingers 67 on the shaft are thereby brought one after another into a position where they may engage the corresponding brush cam 32 on the carriage. The extent of movement of the brush selecting shaft 66 is controlled by the interrupter springs 69 and 71. When the desired position is reached, current will be cut off from the coil 95 and the shaft will stop with one of the fingers 67 in position to engage a particular one of the cams 32. The engagement of the roller 72 at the free end of the spring arm 69 with the starwheel 6S insures the stopping of the shaft in proper position for the release of the desired set of brushes, that is, the roller will be forced into a depression between teeth on the starwheel, thus insuring that the finger 67 will be in the correct position to effectively engage the desired cam The brush selecting device having been adjusted, current will be sent through the coil 90 of the clutch for driving the brush carriage and the brush carriage will then leave its normal position and move toward the brush selecting device. In its initial movement one of the brush controlling cams 32 will be engaged by its respective finger 67 of the brush selecting device and a set consisting of three brushes will be released and forced outwardly by the resiliency of their supporting arms, the outward movement being limited by the surface of the cam. The further rotation of the brush carriage will cause the selector brushes to make contact with the terminals one after another on their corresponding rows. It will be noted that during the passage of the row of cams past the brush selecting device, the contact springs 73 and 7% will be opened, thus insuring that the brush selector will remain stationary at this time so that only one brush set may be tripped. As the brushes pass over the stationary terminals, the springs 42 and 43 controlled by the levers 37, 38 respectively, will measure the extent of movement of the brush carriage as before described. After a predetermined number of impulses have been sent to the controlling mechanism, current may be cut elf from the clutch coil 90 and simultaneously the circuit will be completed through the coils 98 of the stop clutch. The brush carriage will thus be stopped with its selected set of brushes in contact with the desired set of fixed terminals. The brushes will now be centered upon the desired terminals by the engagement of the roller 39 at the free end of the lever 37 in one of the depressions 41 in the plate 10.

When disconnection is desired the switch carriage will be returned to its normal position by the current being again directed through the coil 90, the brush carriage at this time advancing to complete its revolution. Shortly after the brushes leave the bank of stationary terminals, the lever 35 which occupies a radial position at this time will engage the restoring roller 36, thus rotating the restoring yoke about the pivot 31 and forcing the controlling cam of the released set back into its normal position. The rotation of the brush carriage will continue until it approaches its normal position, when the roller 39 will pass over the cam member 46 and stop in the depression 47, this being its normal position, the passing of the roller 39 over the cam 46 causing a momentary engagement of the springs 42 and 43. This impulse may act through a sequence switch or relay or other device to cut off current from the clutch ma net 90 so the brush carriage will stop. The stop magnet 98 may be again brought into operation at this time to prevent the momentum of the switch carriage from advancing it beyond its normal position. In a like manner the brush selector may be returned to its normal position by current being again directed through the clutch magnet 95. This will cause the driving disk 97 to engage the friction disk 96 to complete the revolution of the brush selecting shaft. Upon reaching its normal position the roller 7 2 will enter the depression in the starwheel in which it normally rests, n hirh, beiit'ore stated, is deeper than the other depressions. This will act to cause disengagement of the spring arm 69 from the contact spring 70, which act may be used to cut oli current from the clutch coil 95 and stop rotation of the shaft.

is many modifications of the device here in set forth will be readily suggested to any one skilled in the art, the disclosure herein is to be taken merely as typical and the invention should be limited only by the scope of the appended claims.

I claim 1. In a selector, a rotary carriage, a plurality of independently adjustable brushes thereon, and cams whereby said brushes are normally retained in their retracted position.

2. In an automatic switch, a rotary carriage, a plurality of independently adjustable brushes resiliently mounted thereon, and independently operable cams for controlling the activity of said brushes.

3. A switch carriage comprising a plurality of normally retracted and independently adjustable brushes arranged to travel in unison, independently operable cams for controlling the activity of said brushes, and a rotatable tripping device common to said cams whereby the brushes may be selectively released.

4. A rotary switch carriage comprising a plurality of spring arms having brushes at the outer ends thereof, said arms tending to force said brushes outwardly, and means for selectively maintaining said brushes in their inoperative position.

5. An automatic telephone switch comprising comb-shaped elements having teeth, the outer ends of which form the movable terminals.

6. A movable element of a. telephone switch comprising a plurality of metallic comb-shaped members, brushes arranged in sets, the corresponding brushes of which sets are multiply connected by being formed as the teeth of said metallic comb-shaped members.

7. In an automatic telephone switch, a plurality of normally alined and independently adjustable brushes arranged to move in unison, and cams for normally maintaining said brushes inactive.

h. In a switch, a carriage, a row of brushes supported thereon by spring arms which tend to thrust said brushes outwardly, and cam members for normally maintaining said brushes inactive.

9. In a switch, a carriage, a row of brushes thereon, resilient supporting means for said brushes, said supporting means tending to thrust said brushes outwardly, and a plural ity of alined cam members normally maintaining said brushes inactive.

10. In a switch, a carriage, a row of independently adjustable brushes mounted thereon, means tending to thrust said brushes outwardly, and a plurality of independently movable co-axial cams normally maintaining said brushes retracted.

11. In a telephone switch, a plurality of movable brushes arranged in sets, means tending to thrust said brushes outwardly, and a cam for each set normally maintaining the brushes thereof retracted, said cams being mounted on a common pivot.

12. In a telephone switch, a carriage, a plurality of metallic combs mounted upon but insulated from said carriage, the teeth of said combs being extended to form multiply connected brushes thrust outwardly by the resiliency of said teeth, and means for normally maintaining said brushes inactive. In a telephone switch, a carriage, a plurality of metallic combs insulatively mounted thereon, the teeth of each comb being spaced and extended to form multiply connected l'nushes, said combs being mounted so that the teeth thereof will be arranged in staggered relation whereby corresponding brushes of said combs may be grouped and in alinement.

14. In an automatic switch, a carriage, a plurality of brushes mounted thereon, cams for normally retaining said brushes in their retracted position, means for engaging a cam of the selected brush whereby said brush may be rendered active, a pivotally mounted lever adjacent all of said cams whereby upon the return to normal of said carriage any or all actuated cams will be returned to normal position to retract their respective brushes.

15. In an automatic switch, a carriage, a plurality of sets of brushes mounted thereon, cams for said sets, respectively, normally maintaining the brushes thereof inactive, a device adapted to engage one of said cams to select and render active one of said sets upon the initial movement of said carriage, a pivotally mounted lever operatively associated with all of said cams, and a stationary element on said switch whereby, upon the return to normal of said carriage, said lever will be rotated to return the brushes of the selected to their inactive position.

16. In a switch, a carriage, a plurality of normally inactive brushes thereon, a device adapted to select and render active one of said brushes, and a lever pivotally mounted on said carriage arranged to return the released brush to its inactive position upon the return to normal of said brush carriage.

17. In an automatic switch, a carriage, an interrupter comprising spring arms insulatively mounted thereon, a trackway for each of said arms against which they are held by their own resiliency, one of said trackways being provided with teeth so that upon movement of said carriage the arm in engagement therewith will be caused to oscillate to make and break an electrical contact.

18. In an automatic switch, a carriage, flexible arms insulatively mounted thereon, two fixed trackways of different contours over which said arms ride in the movement of said carriage and whereby said arms alternately approach and recede from one another to make and break an electrical circuit.

19. In an automatic switch, a carriage, two flexible arms insulatively mounted thereon, a pair of contact springs mounted between said arms but insulated therefrom, fixed trackways of different contours over which the respective arms ride in the movement of the carriage whereby said arms are caused to oscillate to open and close said contact springs.

20. In an automatic switch, a carriage, a support therefor, a stationary terminal bank, a frame therefor, uprights having perforations therein, spacing lugs on said frame projecting through said perforations, and means for securing said support to said spacing lugs.

21. In an automatic switch, a stationary Copies of this patent may be obtained for five cents each, by addressing the terminal bank, a frame therefor, uprights having perforations therein, spacing lugs having shouldered ends on said frame projecting through said perforations, a carriage, a support therefor, recesses in said support arranged to receive said shouldered ends, and screws securing said support to said lugs.

In an automatic switch, a carriage, a support therefor, uprights, a terminal bank, a frame therefor, said frame having spacing lugs extending through said uprights and secured to said support.

In an automatic switch, a shaft, movable brushes carried thereby, a set of collector rings carried at one end of said shaft, a hollow projection on each of said rings, insulating disks between said rings, said disks having apertures into which said projections extend, other apertures in said disks and in said rings, and circuit wires extending through said apertures, one end of each wire being connected to a brush and the other end thereof being soldered in one of said hollow projections.

In an automatic switch, a rotatable shaft, movable brushes carried thereby, a set of collector rings at one end of said shaft, a perforated hollow projection on each of said rings, insulating disks between said rings, said disks having apertures into which said projections respectively extend, other apertures in said disks and in said rings, and circuit wires, one end of each wire being connected to a brush and the other end thereof extending through a perforation and soldered within its respective hollow projection, said wires being threaded through the apertures in the preceding disks and rings.

In witness whereof, I hereunto subscribe my name this 10 day of January A. D.,

OSCAR F. FORSBERG. Witnesses O. D. M. GUTI-In, WALTER F. HOFFMAN.

Commissioner of Patents,

Washington, D. 0.

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