US1514625A - Line switches and connection therefor - Google Patents

Description

Nov. 11 1924.

F. A. LUNDQUIST ET AL LINE SWITGHES'AND CONNECTIONS THEREFOR 8 Sheets-Sheet 1 NOV. 11. 1924. 1,514,625

F. A. LUNDQUIST ET AL LINE SWITCHES AND CONNECTIONS THEREFOR Filed Auz.,26 1920 8 Sheets-Sheet 2 QM JW N Nov. 11 1924. 1,514,625

F. A. LUNDQUIST ET AL LINE SWITCHES AND CONNECTIONS THEREFOR Filed Auz. 26 1920 8 Sheets-Sheet 5 11114-1 I//// 35 IMP mx F2613 Nov. 11 1924.

F A. LU-NDQUIST ET AL LINE SWITCHES AND CONNECTIONS THEREFOR Filed Aug. 26 1920 8 Sheets-Sheet 4.

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Nov. 11. 1924. Y 1,514,625

F. A. LUNDQUIST ET AL LINE SWITCHES AND CONNECTIONS THEREFOR Filed Auz. 26 1920 8 a 8 r 6 t 5. M 4 L l A 0Q m TOP H 1 W mum w/ZK W M5 Hw Em c/JB flmJxw WW1. M QC. mm i Am m m m Nov. 11 1924,

Patented Nov. 11, 1924.

UNITED STATES PATENT OFFICE.

FRANK A. LUNDQUIST AND JOHN A. KROPP, OF CHICAGO, ILLINOIS, ASSIGNORS, BY MESNE ASSIGNMENTS, TO HENRY S. CONRAD, TRUSTEE.

LINE SWITCHES AND CONNECTION THEREFOR.

Application filed August 26, 1920. Serial No. 406,145.

T aZZ whom it may concern.

Be it known that we, FRANK A. LUND- QUISI and JOHN A. KRoPP, citizens of the United States of America, and residents of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvement in Line Switches and Connections Therefor, of which the following is a specification.

Our invention relates to line switches and their connections for use in automatic telephone exchanges, and has for its object improvements in such switches and in the bank connections through which subscribers at local stations make connections to idle trunks leading to selectors.

In the accompanying drawings-- Fig. l is a front elevation of part of the bank connections for the line switches. The lower part of the figure represents the condition when the trunks are busy, and the upper part represents the condition when the trunks are idle;

Fig. 2 is a section on line 2-2 of Fig. 1, showing the bank connections in plan;

Fig. 3 is a section on line 3-3 of Fig. 1;

Fig. 4 is an end elevation of the right hand end of the line switch banks, together with part of the supporting frame;

Fig. 5 is a side elevation of a line switch in normal position, together with a part of the banks and supporting frame shown in section;

Fig. 6 is a section on line 6-6 of Fig. 5;

Fig. 7 is an enlarged elevation of certain contacts, being a section on line 77 of Fig. 5;

Fig. 8 is an enlarged section on line 88 of Fig. 5;

Fig. 9 is an elevation (partly in section) which corresponds to Fig. 5, but with the line switch moved to its next to highest position;

Figs. 10 and 11 are sections on lines 10-1O and 1111, respectively, of Fig. 9;

Figs. 12 and 13 are elevations, at right angles to each other, of the line switch relay;

Figs. 14, 15 and 16 are sections on line 14:-14 of Fig. 12, but with the parts in different positions;

Fig. 1'7 is a section on line 1717 of Figs.

12 and 14 showing the parts in normal, or idle position;

Fig. 18 is a section on line 18-18 of F ig. 15;

Fig. 19 is a front elevation of the left hand ends of the crank shafts in the bank connections, with one of the crank turner-s and connections for two others. In this view the lower ten trunks and the twelfth are shown in busy position. The others are in normal or idle position;

Fig. 20 is a section on line 20-20 of Fig. 19, but with all parts in normal position;

Fig. 21 are magnets which are supported below the apparatus shown in Fig. 20 in the manner illustrated in Fig. 22;

Fig. 22 is a view similar to Fig. 20 but with the apparatus in the act of selecting the eleventh trunk, the other parts being in the position shown in Fig. 19;

Fig. 23 is a section on line 23-23 of Fig. 19;

Fig. 241 is an enlarged detail in side elevation, the same being a section on line 24=2 1 of Fig. 19;

Fig. 25 is a front elevation of Fig. 24:;

Fig. 26 is a section on line 2626 of Fig. 25;

Fig. 27 is a section on line 27-27 of Fi 22; and

Fig. 28 is a sectional elevation of the valve used.

The bank connections through which connections are made to selectors consist of lon insulated contact strips 30 and 31 arranged in pairs, and a plurality of pairs of strips are clamped between bars 32 by bolts 33 surrounded by insulation 34. The bars 32 are supported in a framework 35 by bolts 36. To make it possible to have the bank connections of any desired length, they are made in sections of moderate length, and these sections are placed end to end, with a small space between the sections. The bolts 36 pass through these spaces as shown most clearly in Fig. 2. Corresponding strips in the different sections are then electrically connected by wires 37.

The contact strips 30 and 31 are provided with contact projections 38 and 39. respectively These projections are uniformly spaced longitudinally on the strips and areconveniently located adjacent to the clamping bolts 33. The projections 38 are offset to the right, and projections 39 are offset to the left.

Secured to the upper and lower bars 32 are vertical bars 40 which furnish bearings for a series of crank shafts 41 which lie parallel with the strips 3031, and have cranks 42. There is one shaft 41 for each pair of strips 3031, and the cranks lie between the projections 38 and 39, as shown in Figs. 1 and 2. These shafts are made up in sections and are connected together by couplings 43. The connection is such that when the shafts are in normal position, the cranks all he horizontally. On the right hand end of each shaft (Fig. 4) is a. spring 44 which. acts to return the shaft to normal position after it has been moved as will be described hereinafter.

At the left, the left hand section of each crank shaft 41 is of a different length, and each is supported near its end by bearings in an inclined bar 45. (Figs. 19 and 23). The end of each shaft beyond these bearings is bent to form a laterally projecting arm 46, and on each arm is clamped a block 47, part only of which are shown. Pivotally suspended from each block 47 is a bar 48, the structure and function of which will be described hereinafter.

The line switch is contained within a frame 49 bent from flat bar iron so as to form three sides of a rectangle. The ends of these bars slip into grooves in the framework 35 and have their position determined by stops 50 secured to the frame 35. A pivoted catch 51 secured to the frame 35 holds the upper part of the line switch frame 49 from displacement, and a similar catch (not'shown) holds the lower part in position.

Secured between the upper and lower branches of the frame 49 are rods 52 and 53 which are insulated from the frame so that they may serve as electrical conductors.

Tnsulatingly mounted upon these rods is a cross head 54 which has its lower face secured to the upper end. of a vertical tube The tube 55 is telescopically connected to and slides upon an inner tube 56 which has its lower portion secured to a bracket 57, the bracket in turn being secured to the frame 49. The. lower end of the tube 56 has an air pipe '58 secured thereto. Vhen compressed air flows through the pipe 58 to the inner tube 56, the outer tube 55 rises and carries the crosshead 54 up ward on the rods 52 and 53.

Mounted upon the crosshead 54 is some insulating material 59, and secured to thisv material so as to be insulated from each other are brushes 60 and 61 which make electrical connection with the rods 52 and 53, respectively. In electrical connection with the brush 60 is a spring arm 62, and in electrical connection with the brush 61 is a spring arm 63. These spring arms have a tension toward each other, but are normally forced apart by a wedge 64 of insulating material. This wedge is carried on a slide 65 which is guided by pins 66 on the crosshead 54. Slots 67 in the slide permit it to move on said pins, and spring 68 normally holds the slide to the right, as seen in Figs. 5 and 9, so that the wedge 64 spreads the spring arms 62 and 63. Pivoted on the slide 65 is a hook 69 which is normally held against a stop 70 on the slide by a spring 71.

The banks of Figs. 1 and 2 are so arranged that the contact projections 38 and 39 of different strips 30 and 31, lie directly over each other in vertical rows, and the cranks 42 of shafts 41 lie over each other in vertical rows. Each line switch is so located in the framework that the hook 69 lies directly under a vertical row of cranks, and the center point between the contact springs 62 and 63 coincides with the center line of a vertical row of contact projections. When the crosshead of a line switch moves upward, the hook 69 engages the first crank 42 found in normal position, and turns it by lifting" it. This action serves to stop the upward movement of the cross head, and also to start a movement of the slide 65 to the left. The tubes 55 and 56 (Figs 5 and 9) constitute a motor for moving the line switch upward, or, more properly speaking, for moving upward the contact makers 62 and 63 for engaging the contact projections 38 and 39, and the hook 69 for engaging the cranks 42. There is one of these motors for each line switch, and hereinafter these motors will be referred to line switch motors, or as motors 55.

For each crank shaft there is a similar motor 72 consisting of an outer tube 72 and an inner tube 73. (Figs. 19, 20, 22 and 27). These may be designated as trunk motors. Clamped at a suitable position on each mo- "tor 72 is a bracket 83, and pivoted upon screw 74 in said bracket are dogs 75 and 76. A spring 77 connected at a suitable place on the framework serves to retract the trunk motor 72 after it has been raised and released. A spring 78 serves to normally hold the dog 75 in the position shown, and springs 79 serve to hold the dog- 76 in proper position to engage a notch 80 on the bar 48 when the motor rises from normal position. The dogs 75 are guided in slots 81 in a plate 82. An arm 84 on bracket 83 serves as a means for limiting the action of the springs 79 on the dog 76.

011 a bracket 85, and back of each motor 72, is ,pair of con-tact springs 86 and 87. These springs are insulated from each other and from the bracket 85. (Figs. 20, 22 and 27). Supported in another bracket '88, and in line with the motors 72 and their contact springs 86 and 87, are a series of pivot-ed levers 89. The inner ends of the levers 89 engage ends of springs 90 which are secured to the bracket 85. The springs 90 act in compression on the levers '89 so that when one of said levers is at either extreme from mid-position, the spring tension acts to hold spring and lever at that position. When parts 89 and 90 are in the position shown in Fig. 20, they hold the springs 86 and 87 in electrical connection with each other. When 89 and 90 are in the position shown in Fig. 22, the springs 86 and 87 are permitted to "open under the initial tension provided in spring 86. The outer end of each lever 89 projects into the space between two shoulders shown on the inner edge of dog 76. Vhen a motor 72 is in its normal position, the upper shoulder on its dog 76 engages the corresponding lever 89 to close springs 86 and 87. (Fig. 20). Then a motor 72 rises, the lower shoulder on its dog 76 moves the lever to permit said springs to open. (Fig. 22). 7

Running through the telephone exchange is a main air pipe 91, and from this main are branch pipes 92 leadingto valves 93 controlled by armatures 94 of magnets 95. There is one of these valves with its associated magnet and connections for each motor 72. The interior structure of these valves is illustrated in Fig. 28, in which 93 represents the valve body. In this bodyare upper and lower chambers 96 and 97 which contain valves 98 and 99. The valve 99 has a stem 100 which rests upon the armature lever 94. Air pressure exists in the pipe 92, and when the armature 94 is in its retracted position, valve '98 is on its seat and pipe 101 is in free communication with the outside air through the space around stem 100. When the armature 94 is attracted, valve 99 is moved to its seat. and valve 98 is lifted so that compressed air may flow from pipe 92 to pipe 101. For convenience, this entire valve structure is designated by. the character applied to the exterior shell or body.

In the case of the trunk motors 72, but not of the line motors 55, the pipe from the valve to the motor leads through a casing 102- which contains a check valve that permits a ready flow of air to the motor, but not a flow in the contrary direction for exhaust. To provide for the latter there is a by-pass 103 around the check valve. and in this bypass is an adjusting screw 104. The object of this structure is'to permit. the motors 72 to rise quickl when air is admitted to them,

and to retard the return movement under the action of springs 77. This retarded return movement is for the purpose of giving time to complete the trunk selecting operation and to break the circuit for the magnet as at another place before it is remade at springs 86 and 87 by the return of the trunk motor 72 to its lower position. The complete circuit is not shown because it extends into another part of the exchange and involves matters forming no part of the present invention.

Beneath the bracket 88 is another bracket 105, the upper portion of which serves as a guide for the lower ends of the bars 48 which project through openings in the horizontal part of said bracket. livoted to the vertical part of the bracket 105 is a series of arms 106, each one of which is pushed from the bracket 105 by a spring 107. There is one of these arms 106 for each bar 48. When a bar 48 is in its normal (lower) position the corresponding arm 106 rests against it. Vhen a rising motor 72 lifts a bar 48 to turn a crank shaft 41, the corresponding arm 106 is pushed under the lower end of the bar 48 and serves to support it in itsupper position. When the motor 72 falls. the dog 75 turns on its pivot 74 and passes beneath the arm 106. lVhen the motor 72 again rises, the dog 75 pushes the arm 106 back and permits the bar 48 to fall to normal position.

The last crank 42 at the left on each crank shaft 41 is special, and is used to control a pair of contact springs 108 and 109 which are insulatingzly supported at a convenient point on the framework. lVhen a crank shaft 41 is in its normal position, this special crank engages insulation on the face of spring 109 and holds it from engagement with its companion spring 108. When an operating line switch engages some other crank 42 on a crank shaft to turn it, such movement permits springs 108 and 109 to engage each other and close a circuit for the corresponding magnet 95. This in turn opens the corresponding valve 93 to permit compressed air to flow to the motor 72 which rises and completes the turning of the shaft 41, as will be more fully described hereinafter.

The relay shown in Figs. 12 to 18 con.- sists of two spools 110 and 111 which are connected by wires 112 and 113 to a local station. lVhen the subscriber at the local station connects wires 112 and 113 together. he completes a circuit through both coils of the relay. There are other connections. not shown, by which an electrical impulse may be sent through spool 110 and not through spool 111. The matter here involved is the mechanical effect produced upon the structuies shown, and not the circuits by which the coils are energized.

The spools 110 and 111 are mounted in a frame 114, and pivoted to this frame are armatures 115 and 116 which swing transversely toward and from the sides of the projecting cores 117 and 118. The free ends of the armatures 115 and 116 are connected together by a link 119 which has a projecting arm 120. The connections between the link 119 and the armatures 115 and 116 is by pins operating in short slots as will be readily understood by inspection of Figs. 14, 15 and 16. Springs 121 act to retract the armatures to the position shown in Fig. 14, which is the normal position.

When an impulse flows simultaneously through both coils 110 and 111, both armatures 115 and 116 are attracted and the arm 120 is caused to project through an opening 122in the central part of a bridge 123 secured to the frame 114. If, however, an impulse should flow through coil 110 before one flows through coil 111, then the parts will take the position shown in Fig. 16 with the arm 120 thrown over to one side of the opening 122 in bridge 123. If now an impulse should fiow through the coil 111, the arm 120 would engage the inside wall of the bridge 123 and the armature 116 will be retained in its retracted position. Pivotally supported on the bridge 123 is a lever 124, one endof which is in contact with the armature 116, and the other end of which lies under the projecting stem of a valve 125 which is like the valve 93 previously described. If both arinatures are attracted at the same time, then valve 125 is opened and compressed air flows from the main pipe 91 through the valve 125 and the pipe 58 to the motor 55 of Fig. 5. If armature 115 is attracted first, then valve 125 is not opened, and no air flows to motor 55. In the connection between pipe 91 and valve 125 is an adjusting screw 126 for regulating the quantity of air flowing through pipe 58 in a unit of time, and hence the speed with which the motor 55 rises when air is supplied to it.

On the line switch (Figs. 5, 6, 9 and 11) is a long bar 127 pivoted above at 128 and below at 129. A. spring 130 normally hdlds bar 127 so that a catch 131 on the lower portion engages and holds the pivoted lever 132 in a depressed position. In this depressed position, lever 132, pivoted at 133, holds contact springs 134 and 135, and also springs 136 and 137, in electrical connection with each other as shown in Fig. 5. The slide on orosshead 54 has a lip 138 (Fig. 6) which extends part way around the bar 127. 'When the crosshead is raised by the motor 55, the lip slides along adjacent to the bar 127, and when the slide is moved to the left by reason'of its hook 69 engaging a, crank 42, the lip 138 turns the bar 127 on its pivots to release lever 132 and consequently to permit the adjacent contact springs to separate. When the crosshead 54 later falls tact strips shown in plan in Fig. 8, and on the line switch are some coacting contact strips shown in elevation in Fig. 7 When the line switch is placed in the framework, the strips in Fig. 7 enter the spaces between the strips of Fig. 8 and extend electrical connections from one to the other. The wires from the local station go to the strips on the framework and then extend throughthe contact springs on the line switch to the rods 52 and 53, and to the relay of Fig. 12. The circuit arrangement for these connections is not shown because it is not a part of the present invention, but the matter is mentioned here because the operation of the relay, as will be set forth hereinafter, depends upon the condition of the springs on the line switch, and these in turn depend upon mechanical operations to be described.

When the subscriber at a local station lifts his receiver from its hook he connects the two limbs of his line and thus closes a' cirunit through a battery and both coils of the relay associated with his line switch. This attracts both armatures (Fig. 15) and causes the lever 124 to open valve 125. (Fig. 18). This permits compressed air to flow from the main ipe 91 through pipe 58 to the motor 55 of ig. 5. This starts the motor upward.

When the hook 69 comes to a crank 42 which is in its normal position, the body part ward and causes dog 76 to engage rod 48 and complete the turning of the shaft through a total distance of about ninety degrees from normal position. As the dog 76 approaches its uppermost position, the lower shoulder on said dog engages lever 89 to move it from the position shown in. Fig. 20 to that shown in Fig. 22, with the result that the electrical connection between springs 86 and 87 is broken. The springs 86 and 87 associated with each motor 72 are in the circuit for the magnet 95 which controls that motor with the result that when these springs are opened as described, the valve 93 closes and the mo tor 72 falls back. But as; the motor 72 reaches its upper position, the lower end of rod 48 rises above the arm 106 which slips under the rod and supports it after the motor 72 falls back.

When the motor 55 moved the hook 69 into contact with the crank 42 and turned it a short distance, that crank moved laterally into the undercut part of the hook, but before the turning of the crank reached the point of moving the slide 65 on the crosshead 54 to an appreciable extent, the motor 72 came into play and completed. the crank turning operation. This turning moves the slide 65 from the position shown in Fig. 5 to that shown in Fig. 9, and causes the lip 138 on slide 65 (Fig. 6) to turn the bar 127 and release the lever 132. This last opens the springs shown at the right on the line switch and consequently breaks the circuit for the line relay of Fig. 12. Breaking the circuit for the relay permits its armature to return to normal and shuts air from the motor 55. This motor, however, does not fall back because the hook 69 embraces the crank 42 and the spring 68 on the crossthe contact projections 38 and 39 by force of their initial spring tension. As these projections are the terminals of a trunk, and as the contact makers 62 and 63 are connected to the local station through the rods 52 and 53, the operation of finding a crank shaft4 1 in normal position and moving it as described is an operation of selecting an idle trunk.

The release of the apparatus is brought about by causing a second electrical impulse to flow through the magnet 95 of the particular trunk which was selected. This causes the motor 72 to rise a second time. When this motor rose before, the dog 76 swung on its pivot 74 to the right, as shown in Figs. '20 and 22, against the action of the adjacent spring 79. This swinging is due to the fact that the upper end of the dog 76 engages an undercut notch 80, and the upper end of the bar 48 swings on the pivotal center of a crank shaft 41 while dog 76 engages notch 80. This swinging of the bar '48 carries the notch 80 out of the normal path of the dog 76, and as the bar 48 remained elevated after the motor 72 fell back, it will be evident that upon the second rising of the motor the dog 76 will not engage the notch 80. In this second rising, the dog 75 pushes the arm 106 from under the bar 48, and as the dog 76 misses the notch 80, there is nothing to prevent the bar 48 falling to normal position impelled by gravity and the spring 44 on the other end of the moved crank shaft. Returning the crank shaft to normal position permits the spring "68 to move the slide 65 to the right and drive the wedge 64 to spread contact makers 62 and 63 so as to release connection with the projections 38 and 39. The return of the crank to its normal position releases it from the hook 69, whereupon the motor 55 falls back by gravity and all parts return to normal position. In thus falling back the hook 69 is enabled to pass any crank which is in its normal position by said hook turning on its pivot against the tension of spring 71.

\Vhat we claim is:

1. A series of crank shafts each of which has an idle and a busy position, a series of line switches each of which is movable to engagement with a crank shaft in idle position, means for so moving them, said means serving to cause a partial turning of a crank engaged by such movement, a power device associated with each shaft for completing the crank movement to busy posit-ion, contact makers carried by said line switch, and trunk connections engaged by said contact makers when said crank is moved to busy position.

2. A shaft having a series of cranks there on, a motor for moving said shaft from idle to busy position, a line switch, means for operating said line switch to engage one of said cranks to cause the operation of said motor and shaft, means for returning said motor to normal position, and means controlled by the moved shaft for holding the line switch in moved position after said motor returns to normal position.

3. In the trunk connections for a telephone exchange, a crank shaft having a bar secured thereto, a motor, means for operating said motor to engage said bar to move said shaft from idle to busy position, means for releasing said motor, said bar holding said shaft in busy position after said motor falls back, and means for releasing said shaft by a second operation of said motor.

4. In the trunk connections for a telephone exchange, a shaft having a series of cranks thereon, a bar secured to the shaft and serving as a means by which the shaft may be turned, a motor for engaging the bar to turn the shaft, and means operating through a crank on the shaft for starting said motor into operation.

5. In the trunk connections for a telephone exchange, a shaft, a pneumatic motor for turning the shaft, a valve for admitting compressed air to the motor, electrical devices for controlling said valve, and means operating through a preliminary movement of the shaft for controlling the electrical devices.

6. In the trunk connections for a telephone exchange, a switch-stopping device arranged to be slightly moved by the switch which it stop-s,-a motor arranged to quickly move the stopping device from stopping position and to slowly return to its normal position, means controlled by the preliminary movement of the stopping device for starting the motor, a holding device for retaining the stopping device in moved position after motor returns to normal position, and means for releasing the holding device by a second movement of said motor.

7 In the trunk connections for a telephone exchange, a movable element having wipers thereon, a stopping device having an idle and a busy position and normally disengaged from said element, means for causing the engagement of said element with said stopping device, a motor for moving said stopping device from idle to busy position, means for returning said motor to normal position after said stopping device is moved to busy position, a holding device for retaining said stopping device in moved position when said motor returns to normal position, and means for releasing said holding device by a second operation of said motor.

8. In the trunk connections for a telephone exchange, a movable element having wipers thereon, a stopping device normally disengaged from said element, means for causing the engagement of said element with said stopping device, a motor for moving said stopping device, aholding device for retaining said stopping device in moved position, and means for releasing the holding device by a second movement of said motor.

9. In the trunk selecting devices of a telephone exchange, a movable element having wipers thereon, a stopping device having a normal and a busy position and normally disengaged from said element, means for causing the engagement of said element with said stopping device, a motor, means operated by the engagement of said element with said stopping device for causing the operation of saidmotor, connections so arranged that upon a first operation-of said motor said stopping device will be moved r' om normal to busy position and held at position, means for releasing said motor, and means for returning said stopping device to normal position by a second operation of said motor.

10. In the trunk selecting devices of a telephone exchange, a movable element having wipers thereon, a stopping device havinga normal and a busy position and normally disengaged from said element, means for causing the engagement of said element with said stopping device, a motor, means operated by the engagement of said element with said stopping device for operating said motor to move said stopping device from normal to busy position, means for releasing said motor, means by which the advance of said motor is rapid and the return 1s slow, and a holding device for retaining the stopping device in moved position while said motor is returning.

11. A series of insulated strips arranged in pairs, each strip having a series of contact projections thereon, a crank shaft associated with each pair of strips, each shaft having a crank associated with a projection on each of said strips, a line switch having thereon a hook arranged to engage a crank and a pair of contact makers arranged to engage corresponding projections on the strips, and means by which upon a hook engaging a crank the contact makers associated with the hook will engage the projections associated with the crank.

12. A pair of passive contacts, a pair of active contacts provided with a spring tension acting to move them toward each other, a device acting to spread said active contacts, and means by which upon a pair of active contacts being moved to and stopped adjacent to a pair of passive contacts said device will be automatically moved to permit the active contacts to clasp the passive contacts. i

13. A series of passive contacts arranged in insulated pairs, a pair of active contacts insulated from each other and having spring tension acting to move them toward each other, a device acting to spread said active contacts, a motor arranged to move the active contacts along a path adjacent to the series of passive contacts, a stop arranged to arrest the motor movement when the active contacts are adjacent to an idle pair of passive contacts, and means operated through such stoppage for automatically operating said device tocause the active contacts to engage the adjacent passive contacts.

14. A series of passive contacts arranged in insulated pairs, a crank associated with each pair of contacts, a motor, a hook and a pair of active contacts mounted upon the motor and movable thereby to engage a hook and its associated pair of passive contacts, and means whereby upon a hook engaging a crank the active contacts will be given a secondary movement to cause them to engage the associated pair of passive contacts.

15. In the bank connections for a telephone exchange, a pair of sheet metal strips secured together but insulated from each other, said strips having lateral projections so arranged that the projections on the upper strips are offset from the projections on the lower strip, said projections forming passive contacts, and a pair of active contacts having spring tension acting to move thenr toward each other, a device acting to spread said active contact makers, means for moving said active contact makers opposite said passive contacts, and means for moving said device whereby said active contacts are moved to clasp the offset edges of a pair of passive contacts.

16. In a line switch, a reciprocating motor, a crosshead on said motor, a slide on said crosshead, a stopping device ar'anged to be engaged by a. projection on said slide to stop said motor, said motor partially moving said stopping device and an electrical connection completed by the partial movement of said stopping device.

17 A line switch motor, a crosshead mounted upon said motor, a slide on said crosshead, a stopping device arranged to be engaged by a projection on said slide to stop said motor, a trunk motor for moving said stop and said slide from normal position, and an electrical trunk connection completed by such movement of said slide.

18. A line switch motor, a slide carried by said motor, a stopping device arranged to be engaged by a projection on said slide to stop said motor, an electrical connection completed by such stoppage, a trunk motor started into operation by said electrical con nection and arranged to move the slide on the line switch and also to move the stop from normal position, and a second electrical connection automatically completed upon such a movement of said slide.

19. In a telephone system, a trunk selecting switch, a valve for controlling the operation of said switch, a relay consisting of two coils, an armature for each coil having connections for opening said valve when both armatures are simultaneously attracted, and means for retaining said valve in its closed position when one of said armatures is attracted before the other.

20. In a telephone system, a trunk selecting switch, a relay consisting of two coils for controlling the operation of said switch, an armature for each coil and a link connecting the two armatures, said link being so arranged that should one armature be attracted before the other the second armature will be held in retracted position.

In a telephone system, a trunk selecting switch a valve for controlling the operation of said switch, a relay consisting of two coils, an armature for each coil, one of said armatures when attracted opening said valve, and connections so arranged that should the other armature be attracted betore said one armature then said one armature will be held in retracted position.

22. A shaft having a series of cranks thereon, a motor for moving said shaft from idle to busy position, a magnet for controlling the operation of said motor, means controlled by said shaft when in busy position for stopping further movement of said motor, an electrical connection for the magnet controlled by said shaft, and means for closing said electrical connection by an initial partial movement of said shaft.

23. In the trunk connections for a telephone exchange, a plurality of movable elements, a stopping device having an idle and a busy position and normally disengaged from said elements, means for causing the engagement of any one of said elements with said stopping device, a motor for moving said stopping device from idle to busy position, means for returning said motor to normal position after said stopping device has been moved to busy position, a holding device for retaining said stopping device in moved position when said motor returns to normal position, and means for releasing said holding device by a second operation of said motor.

24. In the trunk connections for a telephone exchange, a movable element having wipers and a catch thereon, a stopping device normally disengaged from said element, means for moving said element whereby said catch engages said stopping device, a motor for moving said stopping device, a holding device for retaining said stopping device and said element in moved position, and means for releasing the holding device by a second movement of said motor.

25. In the trunk connections for a telephone exchange, a plurality of movable elements, a stopping device normally disengaged from said elements, means for causing the engagement of any one of said elem'ents with said stopping device, a motor for moving said stopping device, a holding device for retaining said stopping device in moved position, and means for releasing the holding device by a second movement of said motor.

FRANK A. LUNDQUIST. JOHN A. KROPP.

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