US2627554A

US2627554A - Crossbar system switchboard construction

Info

Publication number: US2627554A
Application number: US123431A
Authority: US
Inventors: Edwin L Earle; Richard P Arthur
Original assignee: Kellogg Switchboard and Supply Co
Current assignee: Kellogg Switchboard and Supply Co
Priority date: 1949-10-25
Filing date: 1949-10-25
Publication date: 1953-02-03
Anticipated expiration: 1970-02-03

Description

Feb. 3, 1953 E. L. EARLE ETAL 2,627,554

i m if INVENTORS= EDWIN 1.. EARLE m1 hm Ebm 0 5 6 m mwUm IU NON E L EARLE ETAL CROSSBAR SYSTEM SWITCHBOARD CONSTRUCTION Feb. 3, 1953 Filed Oct. 25, 1949 Feb. 3, 1953 E. 1.. EARLE ETAL 2,627,554

CROSSBAR SYSTEM SWITCHBOARD CONSTRUCTION Filed Oct. 25, 1949 ll Sheets-Sheet 4 WORK BENCH F114 PART 2 INVENTORS EDWIN L. EARLE RICHARD P. ARTHUR MMQ-M H ATTORNEY Feb. 3, 1953 E. L. EARLE ET AL 2,627,554

CROSSBAR SYSTEM SWITCHBOARD CONSTRUCTION INVENTORS= EDWIN L. EARLE RICHARD P. ARTHUR M Mia m7 ATTORNEY CROSSBAR SYSTEM SWITCHBOARD CONSTRUCTION Feb. 3,, 1953 E. L. EARLE ETAL 2,627,554 1 i Filed Oct. 25, 1949 11 Sheets-Sheet 7 FIG.

LLD

INVENTORS= EDWIN L. EARLE RICHARD P. ARTHUR BYM ATTORNEY Feb. 3, 1953 E. L. EARLE ET AL 2,627,554

CROSSBAR SYSTEM SWITCHBOARD CONSTRUCTION A Filed 001;. 25, 1949 ll Sheets-Sheet 8 Feb. 3, 1953 E. L. EARL! ETAL CROSSBAR SYSTEM SWITCHBOARD CONSTRUCTION 11 Sheets-Sheet 10 Filed Oct. 25, 1949 Ill Ill

IIH

|NVENTORS= EDWIN L. EARLE RICHARD P. ARTHUR BM ATTORNEY Feb. 3, 1953 E. L. EARLE ET AL CROSSBAR SYSTEM SWITCHBOARD CONSTRUCTION ll Sheets-Sheet 11 Filed Oct. 25, 1949 S R .m E W U TLT N R R R mmA o v P V W m L D A mm H Mm ER m w L Patented Feb. 3, 1953 CROSSBAR SYSTEM SWITCHBOARD CONSTRUCTION Edwin L. Earle and Richard P. Arthur, Chicago, Ill., assignors, by mesne assignments, to Kellogg Switchboard and Supply Company, a corporation of Delaware Application October 25, 1949, Serial'No. 123,431

Claims. 1

This invention relates to a crossbar-system switchboard construction, but is not necessarily limited thereto. Its primary object is to provide a switchboard of new and improved construction on which the apparatus units required in a crossbar-switching system may be economically and efficiently mounted in a switchroom of a relatively small floor area and of a relatively low ceiling height.

A further object is to enhance the handling. of the switchboard apparatus in transit to the site of installation. This object is attained by (1) providing a switchboard of the foregoing character which comprises separate frame uprights so constructed that they can be manufactured, fully wired, and shipped to the site of installation before the pertaining apparatus units are mounted thereon, and (2) by providing fully wired apparatus units which can be packed and shipped to the site of installation separately from the frame uprights and can be readily mounted thereon. and connected to the frame wiring. These provisions operate to substantially lessen the weight of the items to be shipped and handled.

Additional objects are (1) to provide frame uprights of the foregoing character which, whether used singly or in groups to form a switching frame, may have suitable fully enclosing members attached thereto which include panels that. are readily removable to give access to the apparatus units thereon, and (2) to provide standardized cable-runway parts to support the cables required to interconnect the several frames of the switchboard.

One feature of the invention is that the apparatus units are, for the most part, so mounted within the concerned frame uprights as to slide in and out in the manner of drawers. This arrangement permits efficient use to be made of frames which are relatively deep and which therefore are not required to be of great height to accommodate a desired amount of apparatus.

Further features are that (1) each drawermounted apparatus unit is provided with a flexible terminal cable connecting it to the frame wiring, permitting the unit to be slid out for inspection without disturbing its association with the frame wiring, and (2) each terminal cable connects to the frame wiring through readily attachable and detachable connecting members, permitting easy installation and removal of any such apparatus unit.

Other features are that (1) each frame uprights includes a built-in local cable runway at the top thereof, formed by cable slats attached at with the service compartment and the individual drawer. spaces.

Other objects and features will appear as the description progresses.

I. GENERAL DESCRIPTION It has been chosen to illustrate the invention as applied to a switchboard serving a primarysecondary-spread crossbar telephone system specifically as disclosed in the application of Bellamy and Bowser Serial No. 85292, filed April 4, 1949.

IA. THE DRAWINGS The accompanying drawings comprising Figs. 1 to 21 show views of the chosen preferred embodiment of the invention as follows:

Fig. 1 is a general view of the switchboard, together with the associated powerboard PB and main distributing frame MDF;

Figs. 2 and 3 show the disposition of apparatus units within the drawer spaces in any line-link frame and in the block-link frame;

Fig. 4 is a plan view of a switchroom containing the apparatus of Fig. 1, with the covers removed from the cable runways which are shown empty;

Fig. 5 is a view similar to Fig. 4, but showing the runway cables in place;

Figs. 6, 6A, and 6B are respectively a front view, a plan view, and a right-end view of a fully equipped line-link frame;

Fig. 7 is a general view of a line-linkframe only partially equipped, showing the basic construction;

Fig. 8 is a general sectional view of the ap largement of the lower-left corner of Fig. 9 to show the construction of panel-retaining pins I03;

Fig. 12 is a general rear view of a cover panel H;

Fig. 13 shows a typical frame cable;

Fig. 14 is a sectional plan view of the primary bay of a line-link taken along line I4I4 of Fig. 6, to show a typical flexible terminal cable;

Fig. 15 is an enlarged view taken along line I5-I5 of Fig. 14.;

Figs. 16 and 17 show constructional details of runway bridges used between frames;

Figs. 18 and 18A are respectively, a general rear view and an end view of a double-height drawer unit composed of relay equipment and terminal-pin blocks;

Fig. 19 is a perspective view of a single-height drawer of relay equipment;

Fig. 20 is an enlarged general view of a portion of the block-link frame of Fig. 1, but with parts of the enclosing panels broken away to show apparatus underneath; and

Fig. 21 is a fragmentary sectional view taken generally along line 2I2I of Fig. 20.

113. GENERAL ARRANGEMENT (FIG. 1)

"Referring generally to the drawings, and particularly to Fig. 1, the illustrated crossbarsystem switchboard contains the switchboard apparatus required in the primary-secondaryspread crossbar telephone system, comprising a 1000-line telephone exchange, disclosed in the noted Bellamy and Bowser application. Such an exchange serves a maximum of one thousand local subscriber lines, and has porvisions for forty incoming and forty outgoing tie trunks connecting with other points.

The main distributing frame MDF of Figs. 1, 4, and 5 is of well-known construction. The conductor pairs representing the subscriber lines and the noted tie trunks terminate on one side thereof, while the conductor pairs representing switchboard terminals terminate on the other side, and the terminals on the two sides are interconnected by two-wire jumpers as indicated in the noted prior application.

The apparatus for supplying the required direct-current and alternating-current power to the switchboard frames, and for supervising it, is

mounted on powerboard PB, which may be of any desired construction, but preferably matches the switchboard apparatus in height and appearance, as shown.

Frame TC is the trunk-coupler frame of the noted application, having mounted thereon the trunk couplers required to be used in connection with the above-noted tie trunks.

Frames LLA to LLD are line-link frames A to D of the noted application, each terminating 250 subscriber lines. Frame BL, seen in the foreground in Fig. l, is the block-link frame of the noted application. It is common to trunk-coupler frame TC and line-link frames LLA to LLD, as all calls handled by the switchboard pass therethrough.

The switchboard frames are preferably of a uniform height and depth. Each frame has such width (or runninglength) as is required according to the amount of apparatus to be mounted thereon. Each frame comprises one or more frame uprights having the type of construction shown in Fig. 7 for line-link frame LLD.

Each frame is surmounted by a local cable runway extending longitudinally thereof (parts 23,

4 25, and 35 for frame LLD, Fig. '7). These runways are covered by sheet-metal covers I4 to I8, Fig. 1. .The local runways are interconnected with each other and with powerboard PB by covered runway bridges 3 to I2 of Fig. 1.

Runway sections I and 2 interconnect main distributing frame MDF with frame LLA and frame TC respectively. These runway sections are left uncovered to match the open construction of frame MDF, whereat the necessity for making relatively frequent and extensive jumper changes renders the use of enclosing members undesirable.

The enclosing members for frames TC, LLA to LLD, and BL include eleven horizontal removable panels I15 front and rear for each frame or bay thereof. The eleven spaces respectively covered by these panels comprise a service compartment indicated at SC in Figs. 2, 3, 6, and 6B, followed by ten drawer spaces numbered I to II! as indicated in Figs. 2 and 3. The service compartment S0 at any frame is the space between the cable runway thereof and the baflie I5 thereof (Figs. 6, 6A, 6B, and 7), which act as protective covers for the underlying drawer spaces.

10. DRAWERSPAGE ASSIGNMENT (FIGS. 2 AND 3) Referring to Figs. 2 and 3, the assignment of apparatus units to locations in the ten drawer spaces of the switchboard frames will be described.

ICl. Line-link frames (Fig. 2)

The identity of the apparatus units mounted in the drawer spaces (I to ID) of any line-link frame LLA to LLD is given in tabulated form in Fig. 2. Any such frame comprises a primary bay PB and a secondary bay SB. The uppermost compartment in either bay is the service compartment SC.

Ten primary crossbar switches occupy drawer spaces I to II] respectively of the primary bay PB of any such frame. They are the line-link primary switches 800 of the Bellamy and Bowser application.

Five secondary switches occupy the drawer spaces I to 5 of the secondary bay SB. They are the line-link secondary switches 900 of the lastnoted application.

Drawer spaces 6 and I of any bay SB are occupied respectively by line-controller switches I and 2. They are the line-controller switches 1000 and 1100 of the last-noted application.

Drawer space 3 of bay SB is occupied by a line controller, which is line-controller 1200 in the last-noted application.

Drawer spaces 9 and III of any secondary bay SB are vacant.

As pointed out in the Bellamy and Bowser application, each of the crossbar switches used in the system is preferably of the type disclosed in the pending application of R. P. Arthur for a Crossbar Switch, Serial No. 8,900, filed February 17, 1948. Each such switch has an overall appearance about as shown at PI, SI, and P5 of Figs. 6 and 6B, and each has a pair of rollers 51 (see Fig. 8) at each end thereof to facilitate its desired sliding operation as a drawer.

All control relay apparatus used on the disclosed switchboard is preferably of the type disclosed in the pending application of Bellamy and Arthur for Electromagnetic Relays, Serial No. 20,196, filed April 10, 1948. The noted line controllers (drawer space 8 in any secondary bay SB) each employ the noted relay apparatus mounted to comprise a relay drawer as shown at RD in Fig. 19.

1C2. Block-link frame Referring now to Fig. 3, the disposition of equipment on the block-link frame BL shown therein will now bedescribed.

Block-link frame BL is composed of seven bays, secondary bay .BL-S, control bay BLC, and primary bays BLP| to BL-P5. The uppermost compartment in each bay of the block-link frame is the service compartment SC, as explained for the line-link frames.

102a. SECONDARY BAY In secondary bay BL-S, the ten drawer spaces underneath the service compartment are occupied by secondary switches i to ID, each of which is a crossbar switch of the construction previously referred to. They are the block-link secondary switches 1400 of the noted Bellamy and Bowser application.

IC2b. CONTROL BAY Referring to control bay BL-C, Fig. 3 shows that the first two drawer spaces are vacant, while the third drawer space is occupied by miscellaneous relay appartus (Misc) This apparatus is mounted on a relay drawer such as RD of Fig. 19, relay apparatus thereon comprises section preference relays 1550 and the outgoing :5

controller 1700 of the identified Bellamy and Bowser application.

Drawer space 4 is occupied by a crossbar switch serving as the block-controller switch 1500 of the Bellamy and Bowser application.

Drawer spaces

5 and 6 of the control bay are occupied respectively by duplicate block controlle'rs (B. C. l and B. C. 2') each of which comprises a drawer of relay equipment such as is shown at RD in Fig. 19, and wired as shown for the block controller 1600 of the Bellamy and Bowser application.

Drawer spaces 1 and. 8 of the control bay are occupied by equipment which is shown in circuit diagram in Figs. 18 and 19 of the Bellamy and Bowser application and identified as block translator 1800. Physically, this unit of equipment comprises apparatus mounted on the double height drawer shown herein in Figs. 18 and 18A. The apparatus mounted on the front portion of the drawer comprises the relay apparatus of Fig. 18 of the Bellamy and Bowser application, while the apparatus mounted on the rear (at 131) comprises the terminal-pin blocks shown in Fig. 19 of the Bellamy and Bowser application.

Drawer spaces 9 and H) of the control bay BL- C are vacant, as noted for drawer spaces 1 and 2 thereon.

1620. PRIMARY BAYS Referring now to the five primary bays, B'LPl to BL-P5 of the block-link frame BL, each has two sections of block couplers mounted thereon in drawer spaces I to 8 as shown in Figs. 20 and 21 for the final primary bay BLP 5. There is a section of twenty block couplers I mounted on the rear of each bay as shown in Fig. 20, and a similar section of twenty block couplers 150 mounted on the front of the bay as indicated in Fig. 21. Each block coupler includes a separate angularly shaped common magnetic return plate, together with relay apparatus mounted thereon, together with countingapparatus preferably of the general type disclosed in the application of Bella-my and Arthur for Electromagnetic Counting Devices, Serial No. 43,436, filed August '7, 1948. Any such block coupler has its relay and counting apparatus interconnected for operation as disclosed, for example, in Fig. 5 of the Bellamy and Bowser application.

'I en primary switches (PRI. SWI to PR1. SWIG) are mounted in pairs in drawer spaces 9 and ID of the five primary bays BLPI to BL--P5. These are the block-link primary switches 1300 of the Bellamy and Bowser application. The section of block couplers mounted on the front of any primary bay is associated with the primary switch in drawer space 9, while the section of block couplers mounted on the rear of the bay is associated with the primary switch in drawer space H] of the same bay.

ID. SERVICE COMPARTM-aNT EQUIPMENT (FIG. 4)

Fig. 4 shows the floor plan of a switch. room containing the switchboard apparatus of Fig. 1 and associated powerboard and distributing frame, together with battery 20! for supplying direct current to the switchboard apparatus, charger 202 for charging the battery, and the customary workbench 203. The switchboard apparatus is illustrated in Fig. 4 as it appear with covers removed from the cable runways, and with the runway cables uninstalled to permit an unobstructed view of equipment in the service compartment of the switchboard frames.

In any line-link frame LLA to LLD, a fuse panel 82 is located in the service compartment of the secondary bay, as seen most clearly in Figs. 6, 6A, and 6B. Items BI and 83 are similar fuse panel-s located in the service compartment of trunk-coupler frame TC, and secondary bay BLS of the block-link frame BL, respectively.

Items 19 and B0 in Fig. 4 are terminal-pin blocks located in the service compartment of the primary and secondary bays respectively of any one of the line-link frames LLA to LLD, a seen most clearly in Figs. 6, 6A, and 6B. Items ll 53 in each of the primary bays BL-Pl to BIL-P5, together with the two items I54 in control bay BL-C and item I55 in secondary bay BL-S, are similar terminal-pin blocks located in the service compartment of the bays of block-link frame BL.

When the usual connections (not shown) have been made and cables have been run as shown in Fig. 5, direct current from battery 20! is supplied through powerboard PB tothe noted fuse panels located in the respective frames, and through separate fuses on the fuse panel of any such frame is supplied to respective apparatus units thereon.

Generally speaking, the control wires and talking-path wires which require to be connected externally at any switchboard frame are carried through frame cables to terminal pins in the associated one of the noted terminal-pin blocks 19, 80, and I53 to I55. Desired ones of the terminals in these pin blocks are interconnected with terminals on one or another of the switchboard frames, on the distributing frame MDF, or on powerboard PB, by cables installed in the cable runways as shown in Fig. 5.

IE. RUNWAY Cinemas (FIG. 5)

Referring now to Fig. 5, the runway cables comprise groups '30! to 306 as follows:

The cables in group 353i extend from powerboard PB to. each of the switchboard frames 'IC, LLA to LLD, and BL, carrying the necessary direct-current and alternating-current and signal or supervisory wires to any such frame;

The cables in group 3E2 carry the conductor pairs between frames TC and MDF required for the noted two-conductor incoming and outgoing tie trunks;

The cables in group 303 extend between frame MDF and line-link frames LLA to LLD to .carry the two-conductor subscriber lines betweenth frames;

The cables in group 3% contain the three-wire outgoing-trunk branches and the three-wire incoming-trunk branches between trunk-coupler frame TC and block-link frame BL;

The cables in any one of four groups 305 carry the originating and terminating trunks, along with associated control conductors between the concerned line-link frame LLA to LLD and the block-link frame BL; and

The cables in group 383 interconnect the control bay BL-C of the block link frame with the block-link primary switches mounted on primary bays BLPi to Elli-P5.

For the most part, the Wires in the foregoing cables connect to individual terminal pins in the pin blocks l9, Bi! and IE3 to I55 shown in Fig. i but omitted in Fig. 5 to avoid crowding and confusion.

II. DETAILED DESCRIPTION llA. FRAME CONSTRUCTION (Fins. 6 AND 7) Referring particularly to Figs. 6, 6A, 6B, and

7, the construction of line-link framde LLD of Figs. 1.3, i, and5 will be given, keeping in mind that frames LLA to LLD are all like in construction.

As seen best in Fig. 7, frame LLD includes three principal front members 2

l

22, and 23, and

three oppositely disposed principal

rear members

24, 25, and 26. Considering the noted principal front members. 2! and 22 are upright channel bars on which member 23, a horizontal angle bar, is laid and welded to the ends thereof, providing a rigid inverted U-shaped configuration.

Rear members 24 to 26 are similarly welded together to form a mirror image of the welded front member.

The noted front and rear U-shaped assemblies are placed in the relative locations shown in Fig. 7 and are welded to end floor plates 35 which hold the bottom of the assemblies at the desired distance from each other. Cable slats 36 are welded to the horizontal webs of

top angle members

23 and 25 to hold the top of the assemblies at the desired distance from each other.

Parts

3 and 36 combine the front and rear assemblies into a comparatively rigid frame.

Frame LLD is divided into the two bays, primary bay PB and secondary bay SB, by the intermediate

upright channel members

21 and 28, which are welded to intermediate floor plate 35 and to the underside of horizontal

top members

23 and 26.

The E-shaped frame structure thus far described is brought into constructional four- 1 sided shape by the addition of the centrally disposed longitudinal channel member 33, which is welded to cross angles 29 and 39, welded in turn to the left-end and right-end upright channels, respectively- Channel 33 is further welded to members (such as 21, 28) as needed. That is,

trunk-coupler frame TC is a single-bay frame upright; the starting section of block-link frame BL is a two-bay frame upright similar to any linelink frame; and each of the primary bays BL-Pl to BLP5 is a single-bay frame upright.

The several frame uprights comprising frame BL are preferably bolted together, as by bolts passing through holes (not shown) in adjacent upright end members, similar to end

channels

2 l, 22, 24, 25 of Fig. 7. This sectionalized construction of frame BL promotes handling and shipping, as well as permitting unneeded primarybay sections to be omitted as in small initial installations.

IIB. SLIDE Sorrows Ten pairs of slide supports 40, for drawer slides 50 (Fig. 8) are secured to the defining uprights (2|, 2%, 21, 28) of primary bay PB and ten similar pairs of slide supports 39 are installed in secondary bay SB, on its defining uprights, (21, 28, 22, 25 Slide supports #6 are secured to the upright members by screws 43 as shown best in Fig. 8. When installed, these slide supports add to the previously noted rigidity of the frame structure.

Any one of the first nine drawer spaces discussed hereinbefore is the space between the top 7 of the concerned pair of slide supports 40 and the top of the next underlying pair of slide supports, while the tenth drawer space extends from the top of the lowermost pair of slide supports to the top of angle members such as 29 and 31.

11-0. RAFFLE PLATES A sheet-metal baffle plate 15, having its front and rear edges turned up for rigidity, is laid on the two uppermost slide supports 40 in the primary bay PB, as a protective cover for the equipment units mounted in the underlying drawer spaces, and a similar baiiie plate 25 is provided for the secondary bay SB. Baffle plates 15 may be secured in place by screws entering tapped openings 44 provided in each slid support 46, as seen best in Fig. 8.

Bafrle plates 15 define the lower limit of the service compartment indicated at SC in Figs. 6 and 6B.

IID. DBAXVER MoUN'rmcs As previously pointed out, each equipment unit is fitted into its assigned drawer space within the concerned switchboard frame so as to move in and out as a drawer. Most of the drawermounted equipment units are crossbar switches, and each is equipped with a pair of studsupported rollers at each end. These rollers and studs are shown at 10 and 11 of Figs. 1 and 2 of the previously noted application of Arthur.

In Fig. 8 and in Fig. 10, the two rollers at one end (the left) of the eighth and tenth crossbar switches, respectively, of primary bay PB of frame LLD (Fig. 7) are shown at 57. Their supporting studs 58 are shown in section, as the noted switches are omitted from the drawings to permit an unobstructed view of the slide mechanism.

At any slide mechanism, rollers 51 are resting within a roller channel formed indrawer slide Si! by turning the lower portion thereof inwarda sets;

'9 ly and turning the edge portion upwardly as shown at Fig. 8.

In Fig. 10, the rollers 51 and slide 50 are shown in the position they occupy when the associated apparatus unit is entirely within the frame,

while in Fig. 8, drawer slide 50 and rollers 51 are shown in the position they occupy when the concerned apparatus unit has been pulled part way out. Incident to this operation, each outward roller 5': has engaged outward stop 55 (a bentover tongue attached to slide '50), and has pulled drawer slide 50 outwardly to the illustrated position. This movement of part 55 occurs within the slide-support channel formed within the lower portion of member 40 by a latoral and an upward forming operation to provide guide portion 42.

As seen best in Fig. 8, tipping of slide 50 within slide support 48 is limited by the shank and enlarged head of stud 45, rigidly secured to member 40 as by having a reduced portion of the stud passed through a hole 46 (see next underlying slide 45, Fig-8) and riveted over on the other side. In the noted guiding action, the upper surface of the inwardly shear-formed portion 52 cooperates with the shank of the stud 45, while the inner edge thereof cooperates with the enlarged head of the stud.

Referring further to Fig. 8, when the apparatus unit in question is pulled further out, the

limit is reached when the shank of stud is encountered by the abutment 54 left in part by shear-forming as noted to produce part 52. The unit then occupies a position as shown at Pl, Fig. 6B.

When the fully withdrawn apparatus unit in question is pushed inwardly into place within the confines of the switchboard frame, its rollers 51 first rotate about studs 58 to allow the unit to roll inwardly a considerable distance before the isfirst completely assembled, by telescoping

parts

44 and 50 together and then riveting stud in place, following which the assembled slide mechanisms are secured in place by screws 45,

inreadiness for the roller-equipped apparatus units to be installed. It should be noted that parts 45 and 51! are omitted from parts 49 in Fig. 7, and in one instance in Fig. 8, merely for clarity of illustration and to avoid crowding the drawing, ratherthan to indicate that parts 45 and '59 are applied after parts 40 are secured to the framework.

Keeping in mind that each drawer space is equipped with two slide mechanisms (2. lefthand one as shown in Fig. 8), and a right-hand one (not shown in detail), when a roller-equipped apparatus unit is to be mounted within a drawer space the left and right slides 55 are first pulled out until each is stopped by contact between the associated stud 45 and surface 54. Then, the inward left and right rollers 510i the apparatus unit are introduced into the portion of their slides 5!} which lies outwardly from guide portion 52, as by tiltin downwardly the inward portion of the otherwise horizontally held unit. The unit is then moved partially into its drawer space to pulled out to the position shown at PI, Fig. 6B,

it may be inspected from above and below. If further access is desired, it may then be tilted upwardly to disengage its outward rollers 51 (Fig. 8) from their slides 59, following which the entire unit may be pulled forwardly until the inward rollers 57 thereof are stopped by outward stops 55. The apparatus unit may then be held firmly and rotated upwardly about its inward rollers until the under side of the unit is exposed to hori zontal View, or it may be rotated downwardly to bring "its top side into horizontal view when it reaches the pendant position shown at P5 in Fig. 6B. The pulled-out and partially detachedap paratus unit may thus be rotated more than 180 degrees about the horizontal axis defined by its inward rollers. This may be done quite readily even with a comparatively heavy apparatus unit, as the weight of the unit, or a large part of it is borne by the inward rollers, which are left attached to their respective slide mechanisms. Keeping in mind that the slides 51] are in fully pulled-out position when the noted rotation of the apparatus unit occurs, the net external force applied to the apparatus unit should be outwardly, against outward stops 55, to avoid undesired drawer action.

Following its noted partial detachment from the slide mechanisms, the apparatus unit may be returned to its normal fully attached position by a reversal of the described partial detaching operations.

HE. FRAME WIRING Each switchboard frame (each frame upright in the case of sectionalized frame BL) contains frame wiring suitably related to the wiring represented by the described runway cables, groups 30| to 306, Fig. 5. In describing the frame wiring, line-link frame LLD of Figs. 1, 2, and 4 to 7 has been selected as typical, and the frame wiring required in the primary bay PB of this frame to connect the concerned subscriber lines to the ten primary switches thereof has been selected as a typical example. This latter frame wiring is contained in cable 50, Fig. 13, shown detached from the switchboard for clarity of illustration. Cable 95 extends from line-terminal blocks 79 in the service compartment of the primary bay to the respective drawer spaces of the primary bay, having a separate horizontal leg 92 for each drawer space.

When cable is installed, the vertically disposed portion thereof lies in the space between the upright left-end members 2! and 24 of frame LLD as shown in section in Fig. 14. The main horizontal portion iii of cable 9i lies within the service compartment SC (Fig. 6) of the frame, where the individual wires are connected to respective terminal pins in blocks 79.

Cable 90 and legs 92 thereof also may contain local wires extending between drawer spaces as desired. Frame cables interconnecting the units of bay PB with units of bay SB may have the vertically disposed portions thereof located in the space between intermediate vertical members 2'! 11 and 28 (as shown at 96a, Fig. 14), still further cables (not shown) may be located in the space between right-end

vertical members

22 and 25 to serve the apparatus units of secondary bay SB of the frame.

lIF. CONNECTING STRIPS AND TERMINAL GABLES Pursuant to (1) permitting the frames to be fully wired separate from the apparatus units, (2) permitting the fully wired units to be readily installed, and (3) permitting the installed drawer-mounted units to be withdrawn and returned as described while remaining operationally connected to the frame wiring, the individual wires (such as 93, Fig. 13) in any drawer leg such as 92 of cable 93 are connected to individual terminals (-31 in a pair of aligned terminal strips 6t, and each drawer-mounted apparatus unit is provided with a flexible terminal cable ending in one or more similar terminal strips having terminals which register respectively with the terminals in the first-noted strips when the strips are placed together.

The noted terminal strips are preferably compression-connecting strips of the type fully disclosed in the application of Earle et al. for Compression-Connecting Terminal Apparatus, filed December 20, 1948.

The compression-connecting terminal apparatus for any drawer space is carried on horizontal angle bars 60 of Figs. '7, 14, and 15. Those for any drawer space i to 9 in a bay are mounted on brackets 62 secured to the upper surface of slide supports 4% of the next underlying drawer space, while those of the tenth drawer space are mounted on brackets 13 and 62 (Fig. secured to the underlying angle bars 29 to 32.

While Fig. 7 shows support bars 6!! installed for only one drawer space (#4 in bay SB), it will be understood that each drawer space in each bay of the frame (excepting the two labelled vacant in Fig. 2) is equipped with a set of bars Ell. Each bar 66 has a number of studs 6! disposed therealong to locate and clamp the terminal srips to be placed thereon. Referring to Fig. 10, two support angles 85], extending across the lower portion of the tenth drawer space of bay PB, Fig. 7, are welded at their left end to the two arms of bracket 62, and are similarly secured at the other end (not shown). Bracket 62 is secured to the upper face of adapting bracket i3, secured to the lower web of angle bar 29 by screws M.

As shown in Figs. ll) and 15, the bracket 62 at either end angle bars 69 for any any drawer space I to 9 of bay PB (Fig. 7) is secured by a screw 63 to the upper flange ll of the next underlying slide support 40.

As shown best in Fig. 15, the compression-connecting terminal assembly for any angle bar 56 is applied to the rear sloping surface thereof, the one to Which studs 6! (Figs. 7, 10, 15) are attached, as by spot welding.

Thin insulator strip 3 is first applied to *bar 60, studs 6| being received by location holes (not shown) in strip 64. Spacing insulator strip 65 is next applied, followed by a terminal strip 66 (see Fig. 13) to the terminals 57 of which respective wires 93 of the concerned leg 92 of cable 90 have been secured. The cable leg 92 is conveniently sheltered within the confines of the associated angle bar til. The

noted parts

64, 65, 66, and 6! correspond respectively to

parts

5, 2, 4, and 16 of Figs. 1 to 10, in the noted application of Earle et a1.

During manufacture and assembly of the switchboard frame under discussion, the noted assembly of the wired terminal strips 66 on support bars 68 is followed by the assembly of insulating strips H1, bars fl, and clamp nuts 12, which are tightened for shipment. The parts may remain so assembled until the frame wiring has been tested; the frame has been shipped and installed; the switchboard frames have been connected together by the described runway cables; and the drawer-mounted apparatus units have been installed and are ready for connection to the frame wiring.

As shown in Figs. 6, 6B, 14, and 15, each drawer-mounted apparatus unit is provided with a terminal cable 34 having flexible forward branches 85 connected to the unit, and having fixed rearward branches 86 which afford connecticns to the frame wiring. When such a unit is undergoing the manufacturing operations, the wires in branches 85 of its terminal cable are connected to respective terminal members (not shown) of the apparatus unit, and the wires in fixed branches 86 of the cable are connected to respective terminal members 69 contained in terminal strips 8 (Fig. 15), which are reversed in position to adapt them to cooperatively overlay the respective strips 66 at which the frame wiring has been terminated.

When the terminal wiring of an installed drawer-mounted apparatus unit is to be connected to the frame wiring, the nuts 12, clamp strips H, and outer insulator strips H1 (Fig. 15) are removed from the concerned terminal-assembly groups, following which the terminal strips 68 to which the terminal-cable wires 81 have been attached are laid upon respective frame strips in the relative positions shown in Fig. 15. Parts I0 and H are reapplied to studs 61 and nuts 12 are reapplied and are tightened securely. The wires 81 in the terminal cable are thereby connected respectively to the frame wires 93 through terminals 69 and 81, which are in contact with each other in overlying registry in the

strips

63 and 66 by being woven through the openings in the strips, as clearly disclosed in the noted Earle et al. application. Preferably the main part of cable 84 is fixed rigidly with the support bars 6B, as by lashing the butt ends of cable legs 86 thereto by lacing twine.

Fig. 14- shows a cable 90a lying between intermediate

vertical channels

21 and 28 in association with the forward support bar 69 at the indicated drawer space, while cable 90 of Fig. 16 is shown associated with the rearward support bar 69. The portion of the terminal assembly associated with cable 99a has been omitted from Fig. 15 as unnecessary duplication of the assembly shown therein.

Referring further to Fig. 14, the apparatus unit served by the illustrated terminal cable 84 does not show because of the level (see Fig. 6) at which the view was taken. It has been found desirable to locate each terminal cable 84 along the center of the drawer space as seen best in Fig. 14. This leads naturally to a symmetrical construction providing two smaller flexible legs The central location of cable 3 is rendered feasible by providing two similar terminal assemblies on each support bar (in, a left assem bly and a right one as seen best in Fig. 1 .1..

The outer ends of flexible legs are attached to the apparatus unit as shown at PI and P5 (Fig. 6E). Legs 35 are shown by the full lines in Fig. 14 in the approximate position they occupy when the apparatus unit is in its normal position within the frames. The dotted :lines show the approximate position to which cable legs05 flex when the unit is fully withdrawn to the position shown at PJI, Fig. 618. Parts 85 flex the required further amount when the apparatus unit is manipulated as hereinbefore explained to detach the outward rollers thereof and is then pulled clear and rotated upwardly, or downwardly as at P5, Fig. 6B.

IIG. 'ENcLosrNc MEMBERS The enclosing membersemployed will now be described with particular reference to line-link frame LLD, chosen as typical. The enclosing members at this frame are (1) two end panels I (Figs. 6 to 10), (2) two mullions I06 (Figs. 1, 6, and 7), (3) forty-four removable door panels H5, eleven front and eleven rear for each of the bays PB and SB (Figs. 1, 6, and 12) and (4) four bottom panels H0 (Figs. 6, 613, 7,9, and 10). All of the noted parts bearing the same reference character maybe identical except that the greater width .of primary bay PB requires longer bottom and door panels H0 and H5 than for the corresponding parts used at'secondary 1 bay SB.

As shown in Figs. 6A, and 9, each end panel I00 is of channel-1ike constructionand encloses the end and a small portion of the front and rear faces of the frame. The width of amember I00 is sufliciently greater than the depth of the frame that it may be offset inwardly to form corners ml to receive the ends of door panels H5 flush with the end panels (Figs. 1 and 63).

End panels I00 are secured to the end'members (2|, 24; 22, 25) of frame LLD by a suitable number of oven-headed screws I02, Fig. 11. Each panel I00 is preferably cut square at the top (Figs. 1 and 7) at the level of the upper edge of the uppermost door panels H0, while the lower end of each may have the tongue-like cen tral portion shown in 6B which extends down sufficiently to conceal the ends of longitudinal bar 33, while the front and rear portions of the end panels preferably terminate on the same level as the lower line of bottom enclosures H0.

Each end panel I00 is provided with twentytwo inwardly extending pins I03 (Fig. 11) eleven front and eleven rear for supportingcover panels H5 in cooperation with notches II 9 (Fig. 12) in the cover panels. Each pin I03 has'a threaded portion of reduced diameter passing through a hole in panel I00 and held by anut I04.

Each mullion I00 of frame LLD has a narrow finish portion flush with the covers I I5. finish portion lies between two portions of the mullion which are inwardly offset to provide corners such as corners I0I in end panels I00. 'The mullions are secured to the framework as described for end panels I00, and are similarly provided with pins such as I03, Fig. 11, for supporting the inside ends of cover panels H5.

As shown in general rear view in Fig. 12, each door panel H5 has top, bottom, and side flanges H5, H1, and H0 turned up for rigidity. These flanges may be tack-welded at their intersection points if added rigidity is desired. A depending flange I20, of slightly reduced width and having the tapered corner portions indicated at I2I, extends downwardly from the inner edge of bottom flange H'I. When a door panel II 5 is installed, the tapered tip of its depending flange I20 is behind the upper part of the next underlying cover panel H5. Flange I20 thus closes the rear of the horizontal inter-panel opening The.

"114 left between adjacent door-panels to permit the hereinafter described vertical sliding action rev,quired to engage and disengage the door panels incidental to installing and removing them.

7 Each of the two bottom panels H0 for primary bay PB, for example, closely underlies angle bars 29 and 3I (Figs. '7 and 10), and each has .an inner portion H2 of a reduced width which will pass between the angle bars 29 and 31 .tion H2 is upwardly offset to overlap the upper surface of channel bar 33. The outward edge of Poreach panel I I 0 is turned upwardly to provide a strengthening finish flange III. Two screws H3 (Figs. 7 and 10) pass through each flange III to hold the panel H-0 to the frame members such as 2| and 24. Spacers H4, which may be bentover end tabs of flange II I, hold'the flange spaced outwardly a sufiicient distance to permit the tip of the depending flange I20 of the lowermost door panel H5 to slide down behind it when the door panel is installed.

With the end panels I00, mullions I06, and bottom panels I I0 installed on frame LLD as described, the forty-four door panels H5 may be installed, eleven for the front and eleven for the rear in each bay PB and SB. During installation, any cover panel H5 is held opposite its opening shaped notch H9 receives the associated support pin I03 (Fig. 11),.carried by end panel I00 and mullion I06, permitting the cover panel to move inwardly to the desired flush position. Then the panel H5 is allowed to drop bodily to its final position wherein the toppart thereof is held against outward movement by the noted pins I 03 being received in the vertical portion of notches I I9, and the bottom part of the panel is held against outward movement by the tip of depending flange I20, which has slid behind the upper portion of the next underlying cover panel, or

A behind the upstanding flange I I I 0 (Figs. 7, 9, 10) of the associated bottom panel I I0.

An installed cover panel H5 may be removed by lifting it to clear thepins from the vertical portion of notches H9 and to clear the'tip of depending flange I20 for outward movement. Thiszlifting may be accomplished by inserting the fingers in the horizontal space between the main portion of the concerned cover panel and y as a whole.

the one below it. When so lifted, the panel may be bodily moved outwardly from the frame.

The foregoing describes the enclosing of the principal portion of the bottom of the equipment space within frame LLD, together with the ends and the front and rear faces thereof. The top of the service compartment in the frame is left open except for the runway covers hereinafter described. The top of the uppermost drawer space in each bay is closed by the previously described baflleplatesl5 (Fig. 7), which act as a cover for the ten underlying drawer spaces If desired, similar ballie plates may be applied as individual covers for the respective underlying drawer spaces.

The three cablewells between the upright structural members of frame LLD are preferably en- .15 closed at the top and bottom to complete the enclosing of the switchboard space in which ap paratus units are mounted. These cable wells comprise the one between members 2| and 24, and the ones between members 2'! and 28, and

members

22 and 25. As shown in Figs. 9 and 10, the bottom of the cable well between

members

21 and 25. is closed by well panel 95, sized to match the outline of the well. Two flanges 96, of a length of fit between members 2! and 22, are turned down at the sides. Screws 9? enter these flanges to secure the well panel to end panel lilil and to angle bar 2%.

A similar well panel (not shown) may be used at the top of the well, on a level with the baffle plates 15 and secured between the associated slide support it and end panel its. The top well panel, suitably slotted to accommodate cables such as 90 (Figs. 13 and 14) which may be suitably grommeted to fill the cable-receiving notch (not shown) without chafing the cable.

The remaining cable wells of the frame are similarly enclosed at the top and bottom.

IIH. FRAME BL From the foregoing detailed description of line-link frame LLD, which applies to any of the three similar two-bay, single-upright frames LLA to LLD, the construction of the single-bay frames PB and TC will be apparent. The construction of the multi-upright block-link frame BL, however, may require some additional explanation;

Frame BL comprises six frame uprights placed end to end as shown in Figs. 1, 4, and 5. The starting section of frame BL is the two-bay upright which contains secondary bay BL-S and control bay BL-C. Except for the somewhat different bay widths ordinarily required, this upright is similar to any one of the line-link frames LLA t LLD.

The noted two-bay starting section of frame BL is succeeded by five similar frame uprights (or frame sections) comprising primary bays BL-Pl to BL-P5, respectively. The adjacent ends of the uprights comp-rising frame BL may be bolted together as desired to maintain them in alignment, as by bolts passing through holes in the outside webs of the corner members corresponding to

parts

2I, 24, 22, 25 of Fig. 7.

The enclosing members for frame BL include end panels I90 attached to the end uprights of the frame together with bottom enclosures, baffle plates, and cable-well enclosures as described for frame BL, and door panels I I5. The door panels are removably mounted on the frame by pins supported on end panels I 00 (see Figs. 8 and 11) and on mullions I06 and 106W. Mullion loll of frame BL is similar to mullion I06 of frame LLD, and mullions IUEW are similar to mullions Hi6 except that they are wider in that each covers a portion of two adjacent frame uprights, being secured to each.

IIJ. CABLE RUNWAYS As noted, each frame upright includes a local cable runway extending along the top thereof. As seen best in Figs. 6, 6A, and '1, the local runway of frame LLD comprises the horizontal

structural bars

23 and 26, together with the slats 36 extending between them and welded thereto. The slats 35 support the cables shown in Fig. 5, which are preferably laced or otherwise secured to the slats 36 in the desired groups and layers.

bridges 3 to I2 as shown best in Fig. 4.

The described local runway of frame LLD is typical of the local runway at the other frames, as seen best in Fig. 4.

As before explained, the runways local to the several frames are interconnected by runway VJith inter-frame aisles of uniform width (Figs. 1, 4, 5) all of the runway bridges 3 to I2 are similar and interchangeable.

It will be noted that each bridge 3 to I terminates at the side of each of the two frames which it interconnects, while each bridge 3 to I2 terminates at the end of the frame to which one end of it connects, and is at the side of the frame to which the other end connects. The bridges 'i and I2, which connect with line-link frame LLD have been chosen to illustrate the two noted relationships, and are therefore illustrated in some detail in Figs. 16 and 1'7, respectively.

Each cable bridge I and I2 is a trough-like sheet-metal member having its width dimension about the same as the depth dimension of the switchboard frames. Cable slats I22 are secured to each bridge as by welding. They correspond to slats 36 (Fig. 7) of the local runways of the frames, and are upwardly offset to facilitate lacing the cables thereto.

At each end of either bridge, there is a vertical leg [25, comprising a downwardly bent extension of the bottom wall of the bridge. Leg I25 ends in a foot I26.

At frame LLC of Fig. 1 (similar to the described frame LLD) foot I26 of bridge I (Fig. 16) rests on the bottom flange of structural angle bar 26, and is secured thereto by screws I21, and the other end of the bridge (not shown in Fig. 16) terminates similarly at frame LLD.

At frame LLD (see Fig. 17) leg I 25 of bridge 12 tands between the side flanges of

structural members

23 and 26, and foot I26 rests on the bottom flanges of these members and is secured thereto by screws I21.

Each runway bridge is provided with a sheetmetal cover I23, shown broken away in Figs. 16 and 1'7 to expose the interior of the bridges, but shown in full in Fig. 1.

As noted hereinbefore, runway sections 5 and 2 (Fig. 1), which connect frame MDF with frames TC and LLA, are of the usual open construction. They may be secured to the frames in any desired manner, as by bolts (not shown).

As shown in Fig. 1, the local runways on the several frame are provided with box-like sheetmetal covers I3 to I T, which have portions of their sidewalls and endwalls removed as required for communication with runway sections I and 2 and. covered runway bridges 3 to I2.

At the single-upright frames PB, TC, and LLA to LLD, sing1e-piece runway covers I3, it, and I5 are used. They are similar except for length variations.

At the multi-upright frame BL, a separate section of runway cover (starting section IS, four intermediate sections H, and final section it) is used at each frame upright. Starting and final sections I6 and I8 each have one end closed and one end open, while each intermediate section IT has both ends open. Each section I5 and I'd may have the forward end portion expanded to telescopically receive the adjacent end portion of the next succeeding section, as is common practice in sheet-metal work.

Referring again to Figs. 6 and 6B, the cover I5 for frame LLD has side opening I9 for receiving one end of bridge I (Fig. 1) and end opening 20 1? to receive one end of bridge I2 (Figs. 1 and 6). The other covers and cover sections have similar bridge-receiving openings as required.

Each runway cover preferably has a sidewall configuration as shown best in Fig. 6B for cover I5. The sidewall is offset outwardly near the bottom thereof to provide a widened portion which receives the top structural members of the frame, while the widened portion ends in a shoulder on which the weight of the cover rests.

11K. Morn-SPACE DRAWER UNIT (FIG. 18)

Figs. 18 and 18A show an apparatus unit (block translator BT) which occupies more than one drawer space within the frame upright on which it is mounted. As indicated in Fig. 3, the block translator occupies drawer spaces '5 and in control bay BLC of frame BL.

The unit BT includes two end plates I341, secured together by the underlying longitudinal tie bar I3l, preferably welded to each. Upright angle bars I32 are secured, as by welding, to the front end of plates I39 to provide a mounting location for L-shaped members I33, detachably secured thereto as by screws (not shown).

Members I33 are magnetic return members for relay apparatus as disclosed in the noted Bellamy et al. application for Electromagnetic Relays. This apparatus includes electromagnets I33 and contact assemblies I45 controlled thereby to provide the relay apparatus of the block translator as shown in Fig. 18 of the noted Bellamy and Bowser application.

The apparatus at the rear of unit ET includes groups of terminal pins I31 assembled in blocks to provide the translator terminal pins shown in Fig. 19 of the identified Bellamy and Bowser application. The pins I31 extend through their mounting blocks as shown in Fig. 18A to permit local cable wire (not shown) to be attached ,1

thereto on the inside face of the rear assembly, and to permit local jumper wires (not shown) to be attached to pins I31 on the exposed rear face of the unit.

The blocks in which pins It? are secured are maintained in their illustrated assembled position by clamp bolts I39, extending between lower and upper clamp bars I34 and I35.

The pin-block assembly is secured to end mem bers I35 by hinge pins I35 which pass through the down-turned ends of the lower clamp bar I34, thereby enabling the pin-block assembly to be rotated outwardly when access to the local wiring between the relay and pin-block assemblies is desired. Latch bars I38, detachably secured between the front and rear assemblies as by bolts, normally maintain the illustrated upright position of the hinged pin-block assembly.

End plates I30 are each provided with a pair of rollers 51 through which the unit ET is mounted in slide mechanisms to operate as a drawer, as described in connection with Figs. 6 to 8. Rollers 51 are so placed on unit B'I that, when mounted to slide within a given drawer space, the lower part of the unit occupies that drawer space, while the upper part of the unit occupies the next overlying drawer space, but makes no use of the drawer-slide mechanism thereof. Such slide mechanism may, therefore, be omitted from the last-noted drawer space.

It is contemplated that, when required, the unit BT may be extended downward (as by longer Vertical bars I32) to accommodate depending equipment which will be accommodated in a third drawer space, the one immediately under-- 18 lying the one containing the slide mechanism in which the rollers 5! of the unit are received. Such an extended three-space. unit will thus be drawer-mounted in the intermediate one of the three drawer spaces which it occupies within the switchboard.

IIL. RELAY-DRAWER UNIT (Fro. 19)

Fig. 19 shows relay drawer RD, an apparatus unit for mounting a large amount of relays, and related equipment within a single drawer space of the switchboard. The apparatus on such a unit may be the previously noted miscellaneous relay equipment of frame BL (see Fig. 3) or may be any one of the items referred to hereinbefore as a line controller or a block controller.

structurally, relay drawer RD is composed of similar L-shaped end plates M5 and L-shaped magnet relay bars I45 connecting the end plates and removably secured thereto, as by screws (not shown) entering the inturned flanges of the end plates. Each end plate It! is provided with a pair of rollers 51 for cooperation with slide mechanisms as hereinbefore described for the crossbar switches.

Relay apparatus (including electromagnets it?) may be mounted on bars it as described for bars I33 of Figs. 13 and 18A.

IIM. Bnccn-Coormn MoUNTiNe (Free 20, 21)

As described, each primary bay GLPI to BLP5 of frame BL, has mounting locations for two drawer-mounted primary cross-bar switches in its drawer spaces 9 and Ill, and has mounting locations in its drawer spaces I to 8 for respectively associated sections of block couple-rs, one section at the front of the bay and the other at the rear. Each section includes twenty block couplers associated respectively with the verticals of the associated one of the crossbar switches, as disclosed in the noted Bellamy and Bowser application.

Twenty block couplers I50, comprising the section at the rear of the final ba BL-P5, are shown in part in Fig. 20 where the concerned door panels II5 are broken away. Each coupler I50 is an L-shaped magnetic bar, such as parts I33 and I45 of Figs. 18 and 19, together with relay apparatus and counting apparatus mounted thereon as disclosed in the two noted Bellamy and Arthur applications. Such apparatus wired as shown, for example, in Fig. 5 of the Bellamy and Bowser application. The relay and counter apparatus has not been shown in Figs. 20 and 21 to avoid crowding the lines on the drawings.

As shown in Fig. 21 for a portion of the lefthand end of bay BL--P5, the block couplers I50 of any primary bay are supported at each end on support angle bars I5I welded to the upright structural members, which correspond to El, 24, and 22, 25 of Fig. 7. The horizontal web of each support bar I5I is notched at points I52 to receive the depending web of two block-coupler angle bars I55, one for the front section and one for the rear section. The end portion of the horizontal web of each bar I50 rests on the portion of the horizontal web of its support bar I5! which extends outwardly from the concerned notch I52,.and the two webs may be fastened together, as by screws (not shown) Terminal pins I54 are mounted in blocks supported on bars I55 which lie centrally between the two front .and rear couplers I50 on the same level. Pins I54 serve to terminate the switch-