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Publication numberUS1264826 A
Publication typeGrant
Publication dateApr 30, 1918
Filing dateJul 10, 1916
Priority dateJul 10, 1916
Publication numberUS 1264826 A, US 1264826A, US-A-1264826, US1264826 A, US1264826A
InventorsFrank A Lundquist
Original AssigneeCasper L Redfield
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Automatic telephone-exchange.
US 1264826 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)




1 364,826. v Patented Apr. 30, 1918.




APPLICATION man JULY 10. \9l6.

Patented Apr. 80, 1918.




Patented Apr. 30, 1918.





Application filed July 10, 1916.

To all whom it may concern Be it known that'I, FRANK A. LUNDQUIST, a citizen of the United States of America, and a resident ofthe city of New York, county of Kings, and State of New York, have invented certain new and useful Improvements in Automatic Telephone-Exchanges, of which the following is a specification.

My invention relates to automatic telephone exchanges, and has forits object improvements in the construction and operationv of such exchanges.

In the present application the trunk selecting switches are in the front of drops which are operated by gravity and which slide down rods or wires used both as guides and as electrical conductors. The switches are arranged in rows and are normally supported in an elevated position. The trunk terminals are shafts supported one above another in the path of falling switches. lVhen a falling switch engages one of these shaftsit makes electrical connection thereto and at the same time pushes it out of the path so that it will not be engaged by a second falling switch.

The drawings hereunto annexed are diagrammatic in character. Those which appear to represent structure are not to be con strued as representing actual structure, but rather as representing so much of the general characteristics of structure as will enable the operation to be understood.

In the said drawings- Figure 1 represents three primary switches inthreepositions, and the shafts with which they make connection;

Figs. 2 and 3 are rear and top views, re spectively, of one of the switches;

Figs. 4 and 5 are side and rear views, respectively, of a secondary switch;

Fig. 6 is an enlarged view showing the electrical connection which a drop makes to a trunk terminal;

Fig. 7 is a plan of a trunk terminal; and

Fig. 8 is a diagram of so much of the exchange as is necessary to illustrate the manner of operating,

The drop D is preferably made of some insulating material, such as wood fiber, and is arranged to slide vertically on guide, wires Specification of Letters Patent.

Patented Apr. 30, 1918. Serial No. 108,265. I

35 and 65. Pivoted to the drop D is a contact arm 38 normally heldin the position shown on the upper drop in Fig. 1. A wire or ribbon 116 is connected to one branch of the arm 38, and extends to a spool 127 loosely mounted upon a constantly running shaft 125.

In its upper position the drop D is supported by an arm 23 (Figs. 1 and 8) on armature 33 of magnet R. When themagnet R operates it withdraws the support and the drop falls. A certain amount of friction is provided in the form of a contact spring 36 engaging the guide wires 35. To illustrate the action here involved it will be assumed that the drop weighs eight ounces, and that the friction between 35 and 36 accounts for four ounces. Under these conditions the drop would fall with a force of four ounces. On the other hand, to lift the drop after it had fallen would require a pull equal, to the weight plus the four ounces of friction, or twelve ounces in all. A spring 200 and a set screw 201 (or equivalent devices) are used for determining the normal position ofan arm 38. WVhen the pull on the wire 116 is considerably less than the weight of the drop, the arm 38 will be held in its normal position. When the pull is considerably more than the weight of the drop the spring 200 will be deflected and the arm 38 will take the posit-ion shown in the lower part of Fig. 1.

Supported in brackets 202 are shafts 67 which are bent into crank form as shown in Fig. 7. On the crank-pin parts of each shaft are insulated pieces 39 which are connected together by wires 203 so that all of the insulated parts on one shaft form a conductor. Any convenient stops (such as 204%, Fig. 7 may be used to limit the inward movement of the crank parts.

The shafts 67 are supported one above another and are normally held, by any convenient means, so that the insulated parts 39 will be in position to be engaged by the lower end of arm 38 when drop D falls. The effect of such engagement is to swing the shaft 67 on its pivots so that it will beout of the path of another falling drop, and also to move the arm 38 so as to complete certain electrical connections. The shafts 67 represent trunks leading to secondary switches, and usually there would be ten such shafts in front of a bank of primary switches. Any convenient number of primary switches, as one hundred, would be in front of each bank of shafts, and each switch, when dropped, would engage the first idle one of said shafts. Several primary switches are assumed to be in front of each crank part of shafts 67, and each shaft is assumed to be long enough to provide connections for the one hundred, more or less, primary switches in a bank. Contact strips 118 are back of each crank part and are made into a continuous conductor by wires 205.

The spools 127 are loosely supported on shaft 125 which is continuously running in a direction to wind up wire 116 and lift drop 1) when the spool is driven by the shaft. A clutch member 129 (Fig. 8) and spring 128 provide means for driving the spool, and an arm 121 provides means for disengaging the clutch. The operations involved will be described hereinafter.

The slight friction between the spool 127 and the running shaft 125 is sufficient to keep the wire 116 taut, but the pull is not enough to influence the position of arm 38 or to prevent the fall of drop D when arm 23 is removed. When, however, the clutch is thrown into operation, the strain necessary to lift the weight of the drop and to overcome the friction between 35 and 36 will move the arm 38 on its pivot so that said arm and parts carried thereby will clear any released shafts 67 which may be above the particular trunk which the drop selected in falling.

From the foregoing it will be obvious that the primary switches are trunk selecting switches which are moved by gravity to per form the trunk selecting act, and that this act consists in mechanically moving the trunk terminal from an idle to a non-idle or busy position. Also, that in selecting an idle trunk and in moving it from an idle position, the falling switch comes to a stop and makes certain electrical connections. The apparatus described is simply that considered most convenient for the purpose, and the drawings are largely diagrammatic. Some parts not shown in Figs. 1, 2 and 3 appear diagrammatically in Fig. 8, and will be described in connection with the operation of the exchange.

A secondary switch is shown in Figs. 1 and 5, and in the central part of Fig, 8. It consists of a similar drop D guided on wires 41 and 69. In this case the contact arm 1% is controlled by an arm T, which is controlled in turn by projections S on shaft S. The elevating wire 17 is insulated from the arm 14, and similar insulation is used on the primary switches between arm 38 and wire 116.

The drops D are arranged in banks along side of each other, and associated with each drop D is a shaft S rotated by action of a magnet E. On the shaft S is a pin 206 which, when shaft S is in its normal position, is located under the latch 207 and serves to hold drop D in elevated position. When, however, the magnet E turns shaft S one step, pin 206 is moved from under latch 207 and drop D is permitted to fall.

In front of the primary switches D there is placed one group of about ten shafts 67. In front of the secondary switches there is a pluralityof groups of similar shafts 71, the groups being placed one above another in the same vertical plane. In other words, the bank of shafts 71 in front of the drops D consists of about one hundred shafts one above another instead of about ten shafts as shown in Fig. 1 for shafts 67. The division of this vertically long bank into groups is an electrical division made by grouping the conductors extending from them.

The projections S S etc., on the shaft S are arranged spirally and correspond in spacing to the teeth on the ratchet wheel which moves the shaft. Thus, when the shaft S has been moved one step to release the drop D so that it may fall, the uppermost projection S lies in the path of the arm T and is engaged thereby to move said arm T to push contact arm 44 outward. If, however, the shaft S should be moved two steps instead of only one, then the arm T would pass the first projection S and engage the second projection S If the shaft should be moved three steps, then the drop D would pass the first two projections and the arm T would engage the third one: And so on.

The contact arm 4: 1 is normally held in such a position that, when the drop D falls, said contact arm 14 will not engage any contact shaft 71 unless the arm T previously engages a projection to force said arm 44 outward. The projections S S etc., correspond to the electrical divisions of the shaft 71. Thus, the uppermost projection S corresponds, in position and length, to the uppermost group of shafts 71; the second projection S similarly corresponds to the second group of shaft; and so on. It will be evident that the shaft S with its projections is a group selector, the size of any group being determined by the vertical length of the corresponding projection S S etc.

In Fig. 8 one local station is shown at the upper left hand corner of the drawing, and at the lower left hand corner is one connector switch. These may be of any ap proved construction. Associated with the connector switch, and at the left of the drawing, are shown bank wires, each pair of which extends to the normal connections of a diflerent primary switch. The arrangement and connections of the bank wires are at central oflice. The operation of the magnet it moves the holder 28 to release the drop D which belongs to the calling subscriber.

In falling, the arm 38 of drop D engages the first shaft 67 which is in its normal position, and forces-that shaft inward on its pivot so that it will be out of the path of another falling drop D. At the same time arm 38 on the drop is forced outward so that its outer end engages the segment 39 on shaft 67. Simultaneously, the spring 66 engages the shaft 67 and the guide wire 65. in moving awayfroni normal position, the

' drop D permits contacts 79-80, 85-86 and 85'91 to open, and the contacts 101102 to close. The new position of the drop '1) extends the electrical connections of the local station to an idle one of the secondary switches represented by the drop D The calling subscriber, to select the desired group, then presses-his key A a required number of times to operate it as before and close contacts 32 and 33, whereupon a current-flows from battery Y30-31 3233-2234guide wire 3536-37 38-39-40guide wire l1-4243-44 45 l 6l-7-t8-l9 E5 O-5 152-5 3 st-Y. The first impulse through E rotates shaft S to release drop D so that it may fall, and to bring the first projection S in the path of the arm T. The second impulse moves the shaft S a step farther and brings S into the path of T, S being moved out of that path. If there is only one impulse throughE then the arm T will engage S} and push arm 44: on D outward so that t will engage the first idle shaft 71 in the first group of shafts, and through that shaft be connected to the first idle connector in the first group of connectors. If there are two impulses through E, then drop D willpass the first group of shafts 71 and engage the first idle one in the second group by reason of arm. T engaging S If there are three impulses through E the connection will be to the first idle shaft in the third group, and

so on.

It will be observed that if there are many impulses through E, the drop D will fall a long distance. Under the action of gravity the speed'of a falling body increases rapidly,

local guide ground. The 210131011 of magnet J connects I the generator G to the calling line and the and to keep the variations of 'fallingspeed with-in manageable limits, the armature E "carries a link E having a head E adapted to engage the wire 47 so as to checkthe falling speed of drop 19 each timeF oper and 4&5.

To operate the selected connector, A isfirst operated a required number of times, whereupon current flows from ground at station20-'2l3l-85+-36- 37 38 3 9-404:142432tl5 5-5 6 C 57Z.ground. C closes 59 to 60, whereupon current -fl0ws :Y- 58-59-60C 61Y. Magnet C advances thewipers 77 and 87 over the adjacent contacts to make connections to-the normal wires of the called station.

In ordinary telephone exchanges the 7 con nector is provided 'with a third'wiper which operates on private bankcontac-tsto'prevent the connector from making connect-ions to a busy line. concerned with these non interferi n'g connections, the drawings a show only the wipers 7 7 and 87 'which are involved in making the call itself.

To signal thecalled subscriber, the calling subscriber'presses the keyB,whereupon a current flows :ground at: calling statione 62 6864guide wire 65 '666 768 Wire 69-4 07 1 72-J 57Z ringing circuit is :G 73-747576 77-selected contact po'int'and bank wire to contact spring 79 which is closed for the called station which has its drop D in normal p o s i t i on8()-222l82+eringer- 83hook84-68-64 85 86- closed with drop in normal position-bankwire to wiper 87888990 G.

The magnets R andF of the called station are bridged on this circuit. As they are liable to be effected by the ringing current-andthe operation of R would release the dropD 'of' the called subscriber, a ground connection is provided at thegenerator G so as to provide a battery circuit for F to break the connections for R at contact springs 2627. This circuit is :ground at G 90'- As the present invention is not To restore the connector and the drops to their normal position keys A and B are simultaneously pressed, and at the same time the hook is depressed by hanging the receiver upon it. The contacts closed are normally controlled in an automatic manner by the descent of the receiver hook, but are here assumed to be manually performed. When the hook rises by reason of the removal of the receiver it (the hook) causes its pin 104 to catch on the lever 103, and when the hook descends it pulls down the lever to cause it to push contact 98 against contact 99. Receiver hooks which will operate in this way are shc Wii in my Patents No. 606,7 64, issued July 5, 1898, and No. 747,197, issued Dec. 15, 1903.

The depression of lever 103 causes a current to flow: ground at calling station97 9899--100222324-R25101 102-2829Zground. Also a circuit is completed -:ground at calling station-97- 98 10}3 104 hook 8463-64-105 106--107108F932829Zground The action of magnet F and R is to close the circuit for magnet F as follows Z 29 28 27 109 110 111 112 113 114 115 w 116-117118--49-F l19120Z.

The operations of magnets F and F release the hooks on their armature levers from the pins on the levers 121 and 122 so to permit the springs 123 and 124 on shafts 125 and 126 to push winding drums 127 and 128 to the right into connection with the projecting pins 129 and 130. As the shafts are continuously running, the engagement between pins and drums serves to drive these drums to elevate drops I) and D to their normal positions. When these drops arrive at their upper positions, suitable projections thereon engage levers 121 and 122 to cause them to again force the drums 127 and 128 to the left and out of en agement with their driving pins.

bimultaneously with the current through F and R, a current also flows through J and C of the connector switch. The circuit for J is :ground at calling station-97- 98 103 104 hook 84 636465 66'6768-69'-70-71J57-Z ground. The circuit for C is :-ground at calling station9798-99100-34-35 3637383940414243-4455- 56C57-Z-ground.

Magnet C closes the circuit for C as previously described, and magnet J moves the pin of hook 131 in front of the tail on pawl 132 so that when G attracts its armature 133 the pawl 132 will strike the tail of holding pawl 134 and release the connector switch.

When magnet F operated, as before described, to release lever 122, its armature lever also released holding pawl 208 from the ratchet wheel on shaft S so that spring 209 could return said shaft to its normal position.

What 1 claim is:

1. In a telephone exchange, a drop movable from normal position by gravity, a guide for directing the fall of the drop, a stop in the path of the drop, and means by which an engagement of the drop with the stop serves to complete an electric circuit through the guide.

2. In a telephone exchange, a drop normally supported in an elevated position and movable therefrom by gravity, a contact arm pivoted upon the drop, and drop elevating mechanism connected to the arm and acting to move it on its pivot when lifting the drop.

3. In a telephone exchange, a series of drops movable from normal, position by gravity, independent guides for the difierent drops, a less number of common stopping devices for the drops, means by which a falling drop is arrested by a non-busy stop, and means by which such engagement serves to complete a circuit through the engaged stop and the guide for the falling drop.

4. In a telephone exchange, a drop movable from normal position by gravity, electrical conductors serving as guides for said drop, insulated contact makers carried by said drop, contact pieces located in the path of the contact makers when said drop is moved by gravity, and means by which electrical connections are extended from said contact pieces to said conductors when said contact makers engage said pieces.

5. In a telephone exchange, a drop, an electrical conductor serving as a guide for said drop, a contact maker insulatingly supported on said drop, a series of contact pieces in the path of the contact maker when said drop falls, and means by which upon engagement between the contact maker and a contact piece both contact maker and contact piece will be moved from normal posi tion and the falling movement of the drop will be arrested, said operations serving to extend electrical connections from the engaged contact piece to the conducting guide.

6. In a telephone exchange, a drop representing a subscriber and movable from normal position by gravity, insulated guides for directing the fall of the drop, means by which a drop upon falling makes an electrical connection to one of said guides, other devices operated by impulses sent over said electrical connection, and means by which the operation of said other devices establishes a talking circuit for the subscriber through the guides for his drop.

7. In a telephone exchange, a drop, an arm carried by the drop and normally held in a mid-position thereon, a series of contact pieces in the path of the arm when the drop falls, means by which engagement between said arm and a contact piece will move both from their normal positions, drop elevating devices, and means by which the drop clevating devices will act to move the arm in opposite direction and beyond its normal position.

8. In a telephone exchange, a drop having a contact device movable thereon, guides for said drop, there being a predetermined amount of frictional resistance between said drop and its guides, elevating devices for said drop for returning it to normal position after it has fallen, and means by which the friction between the drop and guides serves to modify the position of said contact device when said elevating devices lif said drop.

9. In a telephone exchange, a drop normally supported in an elevated position, a series of groups of electrical contacts adj acent to the path of said drop when it falls, a contact arm mounted upon the drop and movable with respect thereto, a group selecting device, and means by which upon operating said group selecting device to select a desired group of electrical contacts the drop will be released so that it will fall and in falling will engage the group selector to force said arm into engagement with an electrical contact in the selected group.

10. In a telephone exchange, a vertical series of contacts divided into groups, a drop having a falling path adjacent to said contacts, a contact maker carried by and movable on said drop, a group selector arranged to be adjusted for the selection of any desired group of contacts, means by which upon adjusting said selector for a desired group the drop will be released so that it may fall from its normal position and in falling will engage a predetermined part of the selector, and means by which such engagement will force the contact maker outward into engagement with a contact in the selected group. j

11. In a telephone exchange, a vertical series of contacts divided into groups, a contact maker movable by gravity in a path adjacent to said contacts, a group selector having projections corresponding to the groups of contacts, means for adjusting said selector for the selection of a desired projection, and connections by which upon the falling of said contact maker engagement with the selected projection will cause said contact maker to engage a contact in the corresponding group.

12. In a telephone exchange, a vertical series of contacts, a contact maker movable by gravity in a path adjacent to said contacts, means for moving the contact maker to engagement with some contact in a selected part of the series of contacts, and means for periodically checking the rate of fall of said contact maker in any drop thereof.

13. In a telephone exchange, the combination with a series of contacts, and a contact maker movable by gravity to connection with some contact in the series, of means for checking the acceleration due to gravity so that the actual rate of fall will approximate uniformity.

14. In a telephone exchange, the combination with a series of vertically disposed contacts of a contact maker guided to fall by gravity adjacent to but free from said contacts, and means for projecting said contact maker laterally at any predetermined point in its fall so as to cause it to engage a contact at a desired part of the series of contacts.

15. In a telephone exchange, the combination with a series of vertically disposed contacts, a contact maker guided to fall by gravity adjacent to said contacts but free therefrom, and means for selectively projecting the contact maker laterally at a desired point in its fall to engage a contact thereat, of means for checking the normal acceleration of the falling body.

16. In a telephone exchange, a series of contact pieces serving as electrical terminals, a carrier movable in a path adjacent to said contact pieces, an arm mounted upon said carrier and having a normal position on the carrier such that it will not engage a contact piece when the carrier is being moved, and selective devices for moving said arm from its normal position at a desired part of the carrier movement so as to cause engagement'between said arm and a contact piece in a desired part of the series of contact pieces.


Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, I). 0.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5456608 *Aug 25, 1993Oct 10, 1995Conx CorporationCross-connect system
US5812934 *Jan 25, 1996Sep 22, 1998Con-X CorporationMethod and apparatus for a cross-connect system with automatic facility information transference to a remote location
US6031349 *Mar 20, 1995Feb 29, 2000Con-X CorporationCross-connect method and apparatus
US6265842Jun 9, 1999Jul 24, 2001Con-X CorporationCross-connect method and apparatus
U.S. Classification200/178, 379/306
Cooperative ClassificationH01H67/12