US2942069A - Coordinate switch - Google Patents

Description

June 21, 1960 w. HATTON ETAL COORDINATE SWITCH 2 Sheets-Sheet 2 Filed Sept. 6. 1955 MEMMRES' INVENTORS Y M Am N w A M0 #7 Y B COORDINATE SWITCH William Hatton, South Orange, and George F. McCarthy, Teaneck, N.J., assignors to International Telephone and Telegraph Corporation, Nutley, N.J., a corporation of Maryland Filed Sept. 6, 1955, Ser. No. 532,719

15 Claims. (Cl. 179--27.'54)

This invention relates to electrical switching systems and more patricularly to a coordinate contact switch.

The coordinate or cross-bar switch heretofore commonly used in automatic telephone switching systems is a rather delicately adjusted instrument requiring numerous parts assembled in a compact arrangement. The numerous contacts and selective actuating mechanism must, after assembly, be carefully adjusted for proper operation and since the switch is compact, this calls for painstaking manipulation in order not to disturb other adjusted parts. Where a part becomes worn or otherwise inoperative, the switch assembly usually requires a major disassembling job before the particular part canv be repaired or replaced. Furthermore, most contacts in such switches have a rubbing action which limits the life ofthe contacts and also produces objectionable dust on the working parts, thus interfering with good contact operation.

One of the objects of this invention is to provide an improved coordinate contact switch which overcomes the above-mentioned and many other disadvantages of prior coordinate switches. More particularly, the objects of this invention include the following: a simplified and sturdier switching mechanism; a horizontal multiple contact panel arrangement to which terminals may be coupled'at both ends of the panel and which can be easily divided into separate switching groups, as may be desired; a novel flexible active contact conductor strip; and a selective contact actuating arrangement including spring elements for selecting contact pusher members for actuation and mechanism for actuating a selected pusher member.

One of the important features of this invention is the panel construction containing passive contacts for the switch. The panel comprises twocards or sheets of dielectric, one being provided with printed horizontal multiple circuitry and the other with passive contact areas which are connected through to the printed circuitry.

Other features include the arrangement of the active contacts in the form of one or more flexible ribbon-like strips disposed in overlying relation to a row of the printed passive contacts, a pluralityof resilient pusher members corresponding in number tothe number of passive contacts, disposed for movement relative thereto to engage the active conductor strips and elfect electrical connection between the. strips and the passive contacts. The ribbon-like strips are provided with U-shaped portions to permit flexing thereof when the strip is engaged by a pusher member, the strips being also slotted and provided with dimpled contact portions which are flashed with nickel and coated with a layer of rhodium for making pressure contact with the passive contact. areas which may also be similarly coated with nickel and rhodium. Each selective pusher member is arranged with a cushionlike pad adapted to engage a plurality of conductive strips for multiple contact actuation, the pad operating to insure satisfactory pressure contact for all of the contact. strips and further, to transmit pressure to each of the 2 strips substantially directly proportional to the pressure exerted upon the pusher member. The member for actuating and holding the pusher members include a simple helical spring which is exceptionally durable and positive in its selective operation.

The above-mentioned and other features and objects of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a fragmentary view in side elevation of one panel of a coordinate switch for use in an automatic telephone switching system embodying the contact units of this invention;

Fig. 2 is a sectional view taken alongline 22 of Fig. 1;

Fig. 3 is a view in plan of one section of the switch, the view being taken along line 3-3 of the central portion of Fig. 2;

Fig. 4 is an enlarged sectional view taken along line 4-4 of Fig. 3;

Fig. 5 is a cross-sectional view taken along line 5-5 of Fig. 4; and

Fig. 6 is an enlarged cross-sectional view of one of the ribbon strips shown in Fig. 5.

While this invention is shown as a part of an automatic telephone switching system, it will be understood, however, that the invention is also useful in other switching systems wherever selective switching is required.

Referring particularly to Figs. 1, 2, 4 and 5, it will be observed that the switch is provided with a passive contact panel 1 which includes abase frame member 2 and two layers or cards of insulatingmaterial 3 and 4.Card 3 has thereon printedcircuitry 5, Fig. 1, which constitutes horizontal multiples having terminals at each end of the panel as indicated at 6 and 7. Thecircuitry 5 may be formed on thecard 3 by any one of the many different printed circuit techniques, the circuitry being so arranged as to avoid theopenings 8 through whichselective fingers 9 extend, and to provide groups of junctions 10. Thecard 4 overlies the printedhorizontal circuitry 5 and contains thereon in groups passive contacts 11, 12, 13 and 14, each of which is connected by a junction tab 10a to a corresponding junction ofcircuitry 5. Each such group of passive contacts is arranged in horizontal alignment and constitutes with adjacent groups of passive contacts a vertical row across the panel 1. The flat contact surface of the passive contacts is preferably flashed with nickel and plated with rhodium. While each group of passive contacts is shown to comprise four contacts, it will be recognized by those skilled in the art that each group may be less than four or greater than four depending upon the circuitry associated with each group.

From the foregoing description and reference to Figs. 1-5, it is clear that the groups of passive contacts are arranged in ten vertical rows and that each row has in overlying relation thereto acontact'unit 15. Eachcontact unit 15 comprises a housing havingside walls 16 and 17,end walls 18 and 19 and acover plate 20. The bottom side of the housing is open so that when placed on the panel 1, it encloses a vertical row of passive contact groups. The open side, however, has bridge elements as indicated at 21 and 22, Fig. 4, so arranged as to lie at least between'certain groups, or as shown, between adjacent groups of passive contacts. In overlying relation to each horizontal group of passive contacts is acontact pusher member 23 guided by tworibs 24 and 25 contained on theside walls 16 and 17, Fig. 4. The pusher member comprises asemi-tubular frame 26 which has astem 27 adapted to extend through an opening 28 in the vided with aresilient pad 29, of double tubular stock Patented June 21, 1960 preferably of silicon rubber for engaging the ribbon contact strip.

While thepad 29 is shown of double tubular stock, other shapes or even a single tube may be used so long as it has a tubular or hollow portion exposed for unrestricted fiexing when subjected to compressive action and thereby equalize the pressure of the pusher member onto a plurality of associated ribbon contact strips. One of the advantages of the tubular pressure pad is that its resilient resistance to compression is directly proportional, i.e., a straight line function, within rather wide limits as compared to the logarithmic pressure curve of a solid pad. Thesemi-tubular frame member 26 may also be of other shapes depending upon the shape of the pad stock selected.

Eachunit 15 is also provided with fourribbon contact strips 30, 31, 32 and 33. Each strip is preformed by a stamping or other shape forming operation and is mountedat its ends on the step portions 34 of theend walls 18 and 19, the strip overlying the bridge elements such as 21 and 22 and being slotted lengthwise thereof at least in the portions between adjacent bridge elements. Each strip is also provided with U-shapedportions 35 adjacent its ends which enhances the flexibleness of the strip to permit movement of the strip by any one or more of the pusher members. As shown in Fig. 2, the ends of the strips are provided withterminals 36 and 37 which are receivable in thesockets 38 and 39 on the panel 1.

Referring to Fig. l, the panel 1 is normally chosen of a size such that ten. vertical rows of horizontal contact groups and tenunits 15 of active contact strips are employed. Eachcontact unit 15 has ten pusher members and each vertical row has ten groups of horizontal passive contacts This provides for a possible selection of 100 difierent switching connections between the. horizontallines represented by the horizontal groups of pas.-

sive contacts and those lines represented by the ribbon Panels having still larger or a smaller number of switching connections are,v

strips of each of the contact units.

of course, contemplated. The horizontally disposed conductors which are connected to the passive contacts may be connected from the panel to each of the terminal blocks 6 and 7 or if desired they may be divided between the two terminal blocks. In Fig. 1 such a division is indicated at 40 simply by severing circuitry between the third and fourth units. In such a division, 30 switch.

connections are associated to terminal block 6 and. 70 switch connections are associated with terminal block 7. Other ratios such as 40-60 or 5050 etc., may be provided by suitably severing thecircuitry 5.

As previously mentioned thepusher members 23 are provided withstems 27 which extend through openings 28 in the cover plate of. the contact unit. The fit between the stem and the opening is close so that there is little chance of dust working into the contact unit by way of M the openings 28. Thestem 27 is provided with ashoulder 41 which is adapted to be engaged by a selectingspring 42, Figs. 3 and 4. Thespring 42 is anchored on a holding orvertical bar 43 as indicated at 44. While thespring 42 is preferably a simple helical coil to insure proper resilience and durability, it may take any one of several different forms so long as it is sufficiently resilient and yet provide the desired interlocking operation between the stem of thepusher member 23 and thevertical bar 43. As shown in Fig. 5, oneend 42a is clamped between the twoparts 43a and 43b while the other end 4212 is free for limited movement in the slot 430, Fig. 4. The position of the selectingspring 45 represents the normal position of the selecting springs while the position of thespring 42 is that assumed upon actuation by a selectingfinger 9. It will be understood by those skilled in the art that the sequence of operation is first the movement of the selectingfinger 9 to move one or the other of thesprings 42 or 45 to a selecting position overlying theshoulder 41 on the associated pusher.

member. The next movement is that of thevertical bar 43 which pivots downwardly against the end 42b of the actuatedspring 42, thereby forcing thepusher member 23 against the ribbon contacts. These' two movements are caused by electromagnets, the selectingfinger 9 being connected to a selecting horizontal bar 46 which in turn is connected to anarmature 47 adapted to be attracted by one or the other ofmagnets 48 and 49. The horizontal bar 46 is pivoted by journals 51 and 52. As shown in Fig. 2, themagnet 48 has attracted thearmature 47, thereby causing the selectingfinger 9 to move to the right, Figs. 2 and 4, thereby actuating the spring42 to engage theshoulder 41 ofpusher member 23. Should the magnet 49 attract thearmature 47, theselector finger 9 would then move to the left and engage the spring '45. in association with each of the horizontal bars 46 is a horizontalnormal contact unit 53 and a restoringspring 54 which are engaged by anarm 55 carried by the bar 46. Thevertical bar 43 is pivoted on the frame of the panel 1 as indicated atjournals 56 and 57, Figs. 1 and 2. Each of thebars 43 is provided with anarmature 58 which is associated with anelectromagnet 59 whereby thebar 43 is pivotally actuated in a clockwise direction as viewed in Figs. 1 and 5 to actuate any pusher member that may be engaged by a selecting spring.

Each of the ribbon contact strips 30-33 is provided with longitudinal slots to render the strip more flexible and also to provide the strip with a pair of relatively independent contact dimples in overlying relation to the adjacent passive contact. Two such dimple contacts are shown at 60 and 61 in Fig. 6. The strip isdivided between the two dimple contacts by theslot 62. The slot adds independent resilience to the'contact points. It is also preferred to have theU-shaped portion 35 slotted as indicated at 63. The material for the ribbon strips is preferably copper or brass clad at least on the-contact side with a flash of nickel60a and coated in thearea of the dimple contact with a layer of rhodium 60b. The

nickel flash found most suitable is .0007 inch minimum thick while the rhodium layer was preferably 200 millionths of an inch thick. These proportions are preferred since the nickel provides a good base for the rhodium and the latter does not thin down or otherwise migrate under repeated pressure contact engagement; The passive contacts'llto 14 as well as the dimpled portions of the strip are plated and coated with rhodium to insure durable pressure type contacts. If desired, the dimpling effect may be provided on the passive contacts 11-14 instead of on the strips 30-33, although the latter is preferred.

To summarize the operation of the switchingactiom it may be assumed that theelectromagnet 48 is energized for each of-the ribbon strips 30-33 forcing thecontactdimples 60 thereof into pressure engagement with the associated group of passive contacts 11-14. The holdingbar 43 remains in a holding position until its associated magnet 49 is deenergized whereupon the bar rotates: counterclockwise to another position thereby releasing:

spring 42 andpusher member 23 to return to their normal positions. position, the selectingfinger 9 is left free to move for selective actuation of thespring 45. It should also be recognized that in an installation having more thanone" panel 1 that thefinger 9 may be extended onthe other side. of thebar 46 for use in a second panel.

While we have described above the principlesof -our invention in'connection with specific apparatus, .it is to While thevertical bar 43 is in holding.

be clearly understood that this description is made. only by way of example and not as a limitation to the scope of our'invention as set forth in the objects thereof and in the accompanying claims.

We claim:

1. ha coordinate switch, a panel having a plurality of discrete flat passive contacts spaced apart in a row, an elongated active fiat conductor disposed in overlying relation to said row of passive contacts, pusher members corresponding in number to the number of passive contacts of said row, means disposing each of said pusher members in overlying relation to said active conductor and in alignment with one of said passive contacts whereby movement of any of said members against said active conductor forces said conductor into engagement with the corresponding passive contact, over a corresponding wide area, a holding device disposed for movement rela tive said row of passive contacts, selector elements associated with said holding device, selecting means to selectively position said selector elements relative to said pusher members to effect transfer of an actuating force from said holding device to a selected one of said pusher members when said holding device is actuated, and means for actuating said holding device.

2. A coordinate switch according to claim 1, wherein said active conductor presents a first set of contact engaging surfaces, said passive contacts present a second set of contact engaging surfaces plated with rhodium, and one of said sets of contact surfaces comprises distinct dimples disposed toward the other of said sets of contact engaging surfaces.

3. A coordinate switch according to claim 1, wherein said active-conductor comprises a ribbon-like strip and each of the contact engaging portions of said strip is provided with distinct dimples, covered with rhodium for contact purposes.

4. A coordinate switch according to claim 1, wherein said active conductor comprises a flat ribbon-like strip and said strip is provided with means to enhance flexing thereof when said strip is engaged by one of said pusher members.

5. A coordinate switch according toclaim 4, wherein said strip is slotted lengthwise throughout the portions adapted to engage said passive contacts and the parts of the strips divided by the slot are each provided with a contact dimple plated with a non-corroding metal.

. 6. A coordinate switch according toclaim 4, wherein the means to enhance flexing of said strip includes a U-shaped bend in said strip disposed transversely of the flat surface of said strip. 7

7. A coordinate switch according to claim 1-, wherein said panel has associated therewith a plurality of ridgelike elements one each disposed between adjacent passive contacts to limit contact engagement between said active conductor and the particular passive contact associated with an actuated pusher member.-

8. A coordinate switch according to claim 1, wherein each of said selector elements comprises a helical spring and said holding device includes means to support one end of said helical spring while permitting the other end thereof to be moved by said selecting means into a pusher member engaging position. i i

,9. A coordinate switch according to claim 1, wherein each of said selector elements comprises a helical spring and said holding device comprises a bar pivoted for movement about a longitudinal axis parallel to said row of passive contacts, said bar having means to anchor one end of each of said helical springs and leave the other end thereof free for movement by said selecting means into a pusher member engaging position.

, 10. A coordinate switch according to claim 1, comprising a plurality of said rows of passive contacts which present a first set of contact engaging surfaces, a plurality of said active conductors corresponding in number to the number of said rows which present a second set of contact engaging surfaces, with all said contact eng'ag ing surfaces of said first set lying in a first plane, and

with all of said contact engaging surfaces of said second said contactsbeing arranged in groups with the'cohtac'ts of each group spaced apart in a horizontal row and said groups being arranged in a row at an angle to said horizontal row, flat, ribbon-like active conductors disposed as parallel bands of contacts in overlying relation to corresponding ones of the passive contacts of said groups, pusher members corresponding in number to the number of said groups, means disposing each of said pusher members in overlying relation to said active conductors and in alignment with the passive contacts of one of said groups whereby movement of any of said members against said active conductors forces said conductors into engagement with the passive contacts of the corresponding group, a holding device disposed for movement relative of passive contacts of all said groups, selector elements associated with said holding device, means to selectively position said selector elements relative to said pusher members to effect transfer of an actuating force from said holding device to a selected one of said pusher members, and means for actuating said holding device.

12. A coordinate switch according to claim 11, comprising a plurality of said rows of groups, wherein said passive contacts present a first set of contact engaging surfaces, said active conductors present a second set of contact engaging surfaces, all of said contact engaging surfaces of said first set lie in a first plane, and all of said contact engaging surfaces of said second set which are in the normal position lie in a second plane in spaced relation parallel to said first plane.

13. In a coordinate switch, a panel having a printed board with a plurality of passive contacts arranged in a given plane, said passive contacts being arranged in groups with a number of such groups arranged in a row, the contacts of each group being spaced apart in a row transversely of the row of said groups, a plurality of flat strips adapted to be flexed and forming moveable, active conductors disposed in contiguous relation, spacing means supporting said active conductors in spaced parallel relation to correspond with the spaced relation of the passive contacts in each of said groups, pusher members corresponding in number to the number of said groups, means to locate each pusher member in crosswise relation to said active conductors and in alignment with the passive contacts of one of said groups and to guide said pusher member for movement against said active conductors to thereby flex said active conductors into contact engagement with the passive contacts of said one group, selecting means to select one of said pusher members, and means to actuate the selected pusher member to effect a selected switching opera-tion between said active conductors and said passive contacts.

14. A coordinate switch according to claim 11, wherein, each of said flat strips is slotted lengthwise thereof and the two parts of the strips divided by the slot are each provided with a contact projection.

15. In a coordinate switch, an insulating panel with a printed board having a plurality of fiat passive contacts arranged in rows in a given plane, a plurality of flat, thin, flexible active conductors one each being disposed in overlying relation to a row of said passive contacts, a pair of terminal blocks, each of said blocks having terminals corresponding in number to the number of passive conother of said rows to corresponding terminals of theother of said blocks, and a pivoted contacted pusher for 7 8 flexing and for selectively pressing said active conductors 2,117,702 Burwell May 17, 1938 to client contact closure between a selected active con- 2,300,371 Malinna Oct. 27, 1942 tact and a selected passive contact. 2,447,010 Harrison Aug. 17, 1948 2,516,772 Hickman July 25, 1 950 References Cited in the file of thispatent 5 2,735, 95 01 7,1, 195

UNITED STATES PATENTS 2,066,491 Sheatsley I an. 5, 1937

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