US2406350A - Switching mechanism for signal systems - Google Patents

Description

Aug. 27, 1946. H. c. HARRISON 2,406,350

7 SWITCHING MECHANISM FOR SIGNAL SYSTEMS Filed July 25, 1944 15 Sheets-Sheet .1

FIG.

CODE 80X N0. 2

C905 BOX NO. I

lNl/ENRDR By H. C HARRISON ATTORNEY g- 1945- H. c. HARRISON 2,406,350

SWITCHING MECHANISM FOR SIGNAL SYSTEMS RADIO TRANS.

INVENTOR H C. HARRISON 0%. QMQZ ATTORNEY Aug. 27, 1946. HARRISON v 2,406,350

- SWITCHING MECHANISM FOR SIGNAL SYSTEMS Filed July 25, 1944 13 Sheets-Sheet 3 FIG. 6'

DE! DIZEUDEU DDDIZEEDEE C005 CARDS 80 INVENTOR h. C. HARRISON Qgw i ATmRNE) 7, 1946. H. c. HARRISON 2,406,350

SWITCHING MECHANISM FOR SIGNAL SYSTEMS Filed July 25, 1944 13 Sheets-Sheet. 4

J 'l45 mmmlmcnmlmlmm 6- 24 mmmmnmmuammmu mmrmmmmmummlm m mun-1mm mlmlmlmlmrm mmzmmmlmmlmmu mmmulmmlmcmuu mmmlmmlmmmmm mmmmmmmmmu -evmummmnammmu A 12:; 124 10/ @I guuuuuuuuu' COVER REMOVED TOP lNl NTOR H. C. HARRISON ATTORNEY ug. 27, 3946. H. c. HARRISON SWITCHING MECHANISM FOR SIGNAL SYSTEMS Filed July 25, 1944 FIG. /3

r F n 13 Sheets-Sheet 5 lNVENmR c. HARRISON agm ATTORNEY Aug. 27, 194s.

x H. C. HARRISON S WI'I'CHING MECHANISM FOR SIGNAL SYSTEMS Filed July 25, 1944 13 Sheets-Sheet 8 lNVE/W'DR H C. HARRISON Q0 2&2.

ATTORNEY Aug. 27, 1946. H. c. HARRISON SWITCHING MECHANISM FOR SIGNAL SYSTEMS Filed July 25, 1944 IS'Sheets-Sheet 9 INVENRDR HARRISON ATTORNEY g- 1946;} H. c; HARRISCSN 2,406,350

swrrcnme MECHANISM FOR SIGNAL SYSTEMS Filed July 25, 1944 l3- Sheets-Sheet 10 INVE N 70/? a c. HARR/SGN f" Q m ATTQRNEV Aug. 27, 1946. I c, HARRISQN I 2,406,350

SWITCHING MECHANISM FOR SIGNAL SYSTEMS Filed July 25, 1944 '13 Shets-Sfiget 11 FIG. 40

lNVENTOR H C. HARRISON Q Ga a;

ATTORNEY Aug. 27, 1946. HARRISON 2 063 S WITCHING MECHANISM FOR SIGNAL SYSTEMS Filed July.25, 1944 '13 Sheets-Sheet 12 FE Q INVENTOR H CHARR/SON I ATTORNEY Aug. 27, 1946. H'. c. HARRISON 2,406,350

SWITCHING MECHANISM FOR SIGNAL SYSTEMS Filed July 25, 1944 13 Sheets-Sheet 15 FIG. 37

FIG. 38

I 1 1228 FIG. .390 $0 I INVENTOR ATTOPNEV Patented Aug. 27', 1946 SWITCHING MECHANISM FOR SIGNAL SYSTEMS Henry C. Harrison, Port Washington, N. Y., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application July 25, 1944, Serial No. 546,447

14 Claims. 1

This invention relates to a speech privacy system in which the speech waves are divided into fragments on a time basis and'the individual fragments are transmitted with different amounts of time delay in accordance with a code. Particularly, the present invention relates to a code changing apparatus for use in such privacy system so that one of a plurality of codes for varying the time delay between the individual speech fragments can be selected manually when desired or automatically at preselected time inintervals.

As the security afforded by a fixed code privacy system cannot be relied on beyond the time period required by an unauthorized interceptor to'break the code, it is desirable to be able to change the code from time to time. In the case of a mission of airplanes, for example, requiring a time in excess of the security time period, one or more changes of the code might be desirable during the mission. Under the stress of circumstances attending the mission the changing of codes might be neglected or overlooked entirely if it involved several hand manipulations which were cumbersome, particularly when they were to be performed by an operator with a gloved hand. Accordingly, the present invention contemplates code changing apparatus adapted for the automatic selection of individual codes at predetermined time intervals, or for the manual selection of individual codes by a single hand operation.

A general object of the invention is to provide for the expeditious selection of each of a plurality of individual codes in a speech privacy system.

In a speech privacy system of the type disclosed in the copending application of F. G. Buhrendorf, Serial No. 450,418, filed July 10, 1942, speech waves are recorded n a suitable medium, such as a moving magnetic tape, and are reproduced from this record by a plurality of reproducer magnets spaced along the medium such that the time order of sending out fragments of the speech waves can be varied. A rotary distributor comprising a plurality of interlaced sets of segments and a brush passing thereover breaks the recorded speech waves into fragments of definite length, each being of a small fractionof a second duration. A card perforated in accordance with a preselected code controls the effective connection of any reproducer magnet to any distributor segment of each interlaced set, and thereby varies the time delay between speech fragments. In receiving, each speech fragment is again delayed between the recording medium and distributor brush so as to be supplied to aspeech wave translator in its proper time order.

In a specific embodiment, which is intended for use with a speech privacy system of the above Buhrendorf type, the present invention is con-- cerned with a switching mechanism" associated with each interlaced set of distributor'segments for varying the time sequence with which the speech fragments are supplied to the distributor brush, and comprises a plurality of normallyopen contact pairs each of which includes an elongated contact capable of being flexed at one end and a relatively fixed'contac't. The contact pairs are arranged in spaced relation in a plurality of vertical and horizontal rows such that each vertical row of fixed contacts is connected to a distributor segment of one interlaced set, and each horizontal row of fixible contacts is connected to one reproducer magnet. A plurality of cards each of which is provided with two diiferent sizes of perforations, whose total number is equivalent to the total number of contact pairs but the smaller ones limited to the number of distributor segments in the one interlaced set, intermingled and arranged in vertical and horizontal rows corresponding to those of the contact pairs, is stacked on the upperends of the flexible eontacts.

The uppermost ends of these contacts are disposed in proximity of their associated fixed contacts which are also positioned above the top card of the stack. Each card touches the flexible contacts at the smaller perforations so that such contacts are flexed when'the card is moved in a horizontal direction a predetermined distance. Thus, each card serves" to connect the reproducer magnets to the distributor segments of the one interlaced set in a sequence in accordance with the coding of the smaller perforations alone. A device manually or automatically operated selects individual code cards in the stack and moves them the predetermined horizontal distance for effecting a difierent interconnection of the reproducer magnets and distributor segments of the one interlaced setI As there are two interlaced sets of distributor segments in the specific embodiment of the invention, the two switching mechanisms for such two interlaced sets are operated simultaneously for connecting any reproducer magnet to any distributor magnet of each interlacedset.

The invention will be readily understood from the following description taken together with the accompanying drawings in which:

Fig. 1 is a schematic circuit diagram of a complete two-way terminal of a speech privacy system with which th specific embodiment of the invention can be employed;

Fig. 2isa-f-ragmentary' view, in perspective, of

the cross bar code switch and one perforated code card;

r Fig. 3 shows in outline how a single code box would be connected in the system;

Fig. 4 is a block diagram showing how the apparatus of Fig. 1 would be disposed for four-wire transmission; 7

Fig. 5 shows a detail modification of a portion of the circuit of Fig. 1;

Fig. 6 is a plan view of one accordance with one code;

Fig. 7 is an exploded perspective view of the code box for containing a stack of perforated code cards;

Fig. 8 is a fragmentary plan view of the righthand end of the code box in Fig. 7 showing unoperated and operated positions of the code cards therein;

Fig. 9 is a rear view of a single code switching mechanism;

Fig.- 10 is a plan view of a single code switching mechanism;

Fig. 11 is a front view of a single code switching mechanism;

Fig. 12 is a side elevational view, partly in section, of a single code switching mechanism;

Fig. 13 is a perspective view of one row of contacts in the cross bar switch of the specific embodiment of the invention in Figs. 1 and 2;

Fig. 14 is a perspective view of another row of card perforated in contacts in the cross bar switch of the specific embodiment of the invention in Figs. 1 and 2;

Fig. 15 is a fragmentary perspective view showing the assembly of one row of contact pairs controlled by one operated code card;

Fig. 16 is a sectional view taken along the line iii-I6 of Fig. 12;

Fig. 17 is a side elevation of the housing for a single code switching mechanism;

Fig. 18 is a plan view of the housing for a single code switching mechanism;

Fig. 19 is a sectional view taken along the line I lS-lil of Fig. 12 showing the pawl and ratchet .wheel in its final position after rotating the code card selecting drum one full step;

Fig. 20 is a view taken similarly to Fig. 19 but showing the pawl and ratchet in the position due to the energization cycle of the magnet coil;

Fig. 21 is a partial side elevational view showing how the card selecting drum is disengaged from the code cards to enable the changing of the code box without damaging the code cards;

Fig. 22 is a partial side elevational view showing the code card selecting drum provided with a finger grip for manual operation;

Fig. 23 is a front view of a modification operated by a clock apparatus;

Fig. 24 is a fragmentary side elevational view of the modification of Fig. 2'3;

Fig. 25 is a bottom view of the modification shown in Fig. 24;

Fig. 26 is a view taken along the line 2B-26 of Fig. 24;

Figs. 27A, B, C and D show various operating positions of certain cams in the clock apparatus brush I1 is on start segment 25. tion a release magnet 30, when energized, releases latch 35, Figs. 1 and 5, and thereby allows the Aoass normally opened contact pairs and one closed con tact pair;.

Fig. 32 is a side elevational view of a double code switching line mechanism;

Fig. 33 is a sectional View taken along the line 3333 of Fig. 32;

Fig. 34 is similar to Fig. 32, showing the condition for the insertion and removal of the code boxes in the double. code switching mechanism;

Fig. 35. is a sectional view taken along the line 3535 of Fig. 29;

Fig. 36 is a' cross-sectional view taken along the line 363t of Fig. 29;

Fig. 37 is a sectional View taken along the line 31'31 of Fig. 32;

Fig. 38 is a sectional view taken along the line 3838 of Fig. 29;

Figs. 39A, B, C and D are sectional views taken along the line 39-39 of Fig. 29, showing various positions of the locking cam, including the device for releasing and locking such cam; and

Fig. 40 is a sectional view taken along the line 58-40 of Fig. 34.

Referring to Fig; 1, the privacy system shown enables speech spoken into microphone iii to be sent out in scrambled form over radio transmitter H, and enables speech so transmitted when received on radio receiver [3 to be received as intelligible speech in headset I4. Transmission and reception could also be by wire as Well.

The scrambling of the outgoing speech and the unscrambling of the incoming speech is accomplished by magnetic tape i5, commutator l5 (laid out in a straight line) traversed by brush l7, and the plurality of magnets associated with the magnetic tape and comprising recording magnet R, and reproducer magnets A I. The usual erasing magnet is not shown. The commutator segments and reproducer magnets are interconnected through code boxes l8 and it. Each of these boxes contains a plurality of cards periorated in advance in accordance with a preselected code and arranged in stacked relation. One card from each box serves to condition the system for transmitting and/or receiving scrambled speech in accordance with two codes interlaced with each other. The mechanism which selects individualcards in each code box and which constitutes the subject-matter of the pres- .ent invention will be described in detail hereinafter.

The operation of the system shown in Fig. 1 will now be briefly described to provide such background as is necessary to a full understanding of the code card selecting mechanism constituting the present invention. Let it be assumed that the communicating parties have agreed on the codes that are to be used at a particular time and that perforated cards embodying such codes are selected in the code boxes i8 and I9 at each station, in accordance with the present invention to be explained later, of which stations there may be two or more. The sending of a start impulse from contacts 35 of the transmitting station release all brushes ll at all stations when At each stabrushes I! at all stations to start out on a revolution in phase with each other.

Assuming first that the station shown in Fig.

' 1 is to transmit scrambled speech and as such station is normally in the receiving condition the talking party presses button E2 to supply talking current from battery M via key 4!, winding 42,

radio choke 43 and contact 44 of button 12 to microphone Ill, and at the same time speaks thereinto. Contact 45 of button l2 closes an energizing circuit for relay 32 from battery, through the operating winding of relay 32 and radio choke it which relay operates and locks up through latch 3 to ground. The operation of relay 52 serves to supply energizing current from the battery associated with its outer armature and lead 47 to relays 25, 2t, 21, 28 and 29, all of which operate to condition the system for the transmission of speech. Relay 25 disconnects receiving lead 28 from radio receiver l3. Relay 26 opens receiving branch conductor lead 48 leading to receiver i i and closes sidetone lead 49 thereto. Relay 27 connect lead 50 to radio transmitter l i. Relay 28 opens the receiving circuit for the start pulse. Relay 2 9 closes the start pulse generating circuit which will be hereinafter pointed out.

Speech current from microphone l are applied through button 22, key 4!, primary winding d2 of input transformer 5i, amplifier 52, output transformer 53 including winding E i and lead 55 to the recording magnet R. Filter 55 eliminates a signal band of frequencies of the order of 2000 cycles which frequency band is reserved for transmitting the starting pulse to be explained later. The speech currents are recorded on the moving magnetic tape l5 and then passed along to the reproducer magnets A I. A portion of the speech originating in microphone I0 is diverted from the output of amplifier 52 via output transformer 53 including winding 54 and over lead 29 to the headset I l so that the talking party can gauge the loudness of his speech input to the system via microphone IS.

The code boxes l8 and it permit crossconnections between any commutator segment and any reproducer magnet of each interlaced set so that as brush il sweeps over any given segment any preselected reproducer magnet can be connected at that time to the brush. By properly placing certain perforations in the code cards, as will be more fully explained later, the

individual reproducer magnets A I can be connected to the brush i? in any order and at any given time in the cycle. Brush l! is connected over lead input transformer E0, am-

plifier 59, output transformer ti, and potentiometer 62 to radio transmitter ll. Amplifier 59 serves to amplify the scrambled speech.

Once each revolution of the brush 11, when it is in contact with short synchronizing commutator segment the contacts 35 are closed.

Since relay :3 is energized and therefore operated at this time, condenser 53 discharges through inductance it which forms a part of a filter also including condensers 6 and 68, and inductance 69. Condenser E3 was previously charged up from battery 6d through resistor 65. This filter generates a damped wave whose frequency is about 2099 cycles per second and which serves as the starting pulse above mentioned. One portion of the damped wave is applied through coil d9, 19, upper contact of relay 28, and filter ii to the input of gas-filled tube 12. This tube breaks down on the first suificiently large positive swing of its grid, and thereby causes the energization of tripping relay 3%, Figs. 1 and 5, which releases the brush arm for another r0- tation. At the same time another portion of the damped wave is applied over lead 73 to amplifier -59 for transmission to the distant station.

control grids of amplifier 52 and gas tube 72, varying as the level of the input varies, so as to maintain a substantially constant output level. The bias on the amplifier 52 controls the sensitivity of the gas tube 72, increasing or decreas ing it as a function of signal level to maintain the time of release of the latch 3! independent of receiving level and to maintain the discrimination between signal and speech level approximately constant.

The system of Fig. 1 may also be used for sending tone telegraph by means of a key 31 when switching key M is thrown to the left. Tone for this purpose is derived from a pilot generator 34 driven from 7 a motor 33. Side switch 38 associated with the telegraph key is closed to energize relay 32 when sending and is opened to deenergize relay 32 when receiving. The dot and dash telegraph signals are transmitted in scrambled form as in the case of transmitted speech.

When the talking party stops talking he releases button l2 thereby causin the system to revert eventually to the receiving condition. In due course relay releases to reconnect lead 233 to the radio receiver l3 whereby incoming scrambled speech is now applied through primary winding 2! of input transformer iii and amplifier 52 to the recording magnet R for recording on the magnetic tape it. The reproducer magnets and commutator segments through the perforated code cards of code boxes is and I9 render intelligible the incoming scrambled speech. The intelligible speech is then applied through amplifier 5i; and outer contact of deenergized relay 25 to headset M.

In releasing, relay 29 disables the pulse generating circuit under control of cam operated contacts 35; and relay 28 connects secondary winding 3%: of output transformer 53 of amplifier 52 to the 2000 cycle band-pass filter ll so that the tripping tube :2 and relay are placed under control of the 260i) cycle start pulses from the distant transmitting station. Band elimination filter 56 attenuates such pulses and thereby precludes them from reaching recorder magnet R.

Fig. 5 shows the tripping relay 33 arranged to prevent the release of latch 31 and thereby the brush H for another revolution, in the absence of starting pulse, in order to prevent false signaling b an enemy When the system of Fig. l is arranged for receiving normal speech, In Fig. 5 tripping relay 30, latch 3!, brush H are shown together with relay 39 energized when the brush H is stationary and provided with contacts which shunt both radio transmitter l! and receiver l4. Relay 39 is sufficiently slow so as not to close itscontacts when brush I! is stopped during normal operation. Speech can only be heard, therefore, if the brush I7 is operating normally. If the talking party .fails to hear his own speech while he is talking he knows that his speech is not being transmitted, This could occur if the system fails for any reason to operate or if the brush I! should accidentally fail to start but remains stationary for an abnormal time. The talking party is thus Warned against sending out non-secret transmission and is enabled to distinguish between a received secret transmission and a false message.

Fig. 3 shows a single code box l8 employed with a ten-segment commutator l6 and nine-reproducer magnets A I. The single code box i8 is constructed similarly to the individual code boxes I8 and H] of Fig, 1. In Fig, .4 there is illustrated a, system whereby any number of stations can communicate with one another secretly by four-wire transmission. The circuit elements are identified in the drawings by the same reference characters as in Fig. l, with prime works to indicate circuit elements that are required in duplicate. As two separate machines are required, this arrangement permits the use of a very great number of code combinations since the two codes used for transmitting can be entirely independent of the two codes used for receiving. The converse of the two codes used inv the transmitting machine is set up on the receiving machine. The individual code boxes l8" and I9" are constructed similarly to code boxes 58 and I9. A complete description of the above may be had by referring to the copendin application of F, G. Buhrendorf,

supra.

In accordance with the present invention the interconnection of twenty commutator segments and nine reproducer magnets is controlled by code boxes i8 and i9, Fig. 1, each of which embodies a plurality of code cards formed with a plurality.

of perforations of suitable shape in two different sizes in accordance with a preselected code and arranged in stacked relation. In one illustration, for example, each code box included twenty code cards. Referring to Fig. 6, code card 80 is provided with ninety perforations arranged in ten vertical rows andnine horizontal columns. Each row corresponds to a commutator segment and each column to a reproducer magnet. Eight of nine perforations I23 in each row are of the same size, for example, inch X inch, and the ninth perforation I2 3 is of a smaller size, for example, inch x A; inch.

Each of eight horizontal columns contains one smaller perforation and the ninth column in chides two smaller perforations. This is so for the reason that as nin reproducer magnets are to be connected to ten commutator segment of each interlaced set at least one reproducer magnet must be connected to two commutator segments. The preselection of codes is not influenced by the larger perforations but by the smaller perforations alone as will b pointed out hereinafter. The code card 8E3 also embodies a projection 8| on its upper right-hand edge and a tongue-like projection 82 substantially at the center of its lefthand edge. The functions of these projections will be mentioned later. The individual code cards are composed of a suitable electrical insulating material of proper dimensions which in one illustration comprises mil phenol linen.

Code box 84, Fig. 7, comprises two complementary frames 85 and 88 arranged substantiall in a U-shape so that its right-hand end is entirely open to allow the insertion of the individual code cards and its left-hand end is entirely closed ex- V cept for a vertical center opening 81 which accommodates the tongue-like projections 82 of the individual code cards. The extreme right-hand end of the frame 85 embodies an L-shaped cutout portion 83 which receives the projections 8| of the individual code cards so as to insure the insertion of the individual code cards into the code box with the top side of the cards always up. The inner surfaces of the longitudinal sides of the frame 85 and 86 and the portions of both thereof in proximity of opening 81 are formed with recesses 89 to provide suitable spacing between adjacent code cards to permit their movement in a manner and for a purpose both of which will become apparent later. 7

. Upper clamping member 90 and lower clamp-- ing member 9! maintain the frame 85 and 86 in assembled relation by machine screws 92. These project through suitable openings 93 in the'upper clamping member 86 and frames 85 and 8S, and are anchored in internally threaded openings 94 formed in the lower clamping member 9|. Back plate 95 secured to the frames 85 and 86 by machine screws 96 encloses the code cards within the code box 8-3. Referring to Fig. 8 it will be observed that a space intervenes between the right-hand edges of the code cards 80 in their normal position and the inner surface of the back plate 95. This is to permit sliding movement of the code cards in a manner that will be subsequently described.

Figs. 9, 10, 11 and 12 disclose a single code switching mechanism embodying ninety fixed electrical contacts Hi8 and ninety flexible contacts Nil, one of which is associated with'each fixed contact and flexed at one end by code cards Bil in a manner that will be subsequently described. Fig. 13 shows an electrically conductive member 98 formed with nine contacts Nil having their adjacent ends integral therewith and arrangedin spaced relation in a vertical plane, and

their opposite capable of being flexed and terminating in a horizontal plane. Thus the nine contacts ml terminate efiectively in a common contact H33. Each contact llil includes on one surface a contact point I64 composed of a precious metal. Fig. 14 shows nine fixed contacts l0!) having corresponding end portions mounted in spaced relation in a vertical plane in electrical insulating member Hi5. Thus approximately four-fifths of each contact lei! projects above the insulating member I and terminates in a horizontal plane and approximately one-fifth extends therebelow and terminates in a horizontal plane. Each contact I86 embodies on one surface a contact point 266 formed of a precious metal.

Ten contact assemblies of Figs. 13 and 14 are that contact points I84 and I6 of the respectively associated contacts HM and I are oppositely disposed and capable of engagement with each other.

Referring to Fig. 16, the associated pairs of contacts H39 and I0! comprise ten individual vertical rows and nine horizontal columns. As contacts Iii! are longer than contacts I30, the former constitute ten vertical rows and nine h'orizontal columns which correspond to the previously described spacing of the perforations in the code cards 8. As hereinbefore pointed out, each vertical row of contacts lfll terminates in common contact I03, Figs. 11, 12, 13 and 15; and each contact I90 terminates individually in both rows and columns, Figs. 11, 12 and 14, except as hereinafter modified.

Figs. 17 and 18 show a U-shaped housing I09 having a cut-out portion H0 in each of its two horizontal side walls; This provides effectively the upper portion of-support l 09 with an upright H2 at each of four spaced points arranged in a rectangular manner. Each upright IIZ contains a vertical recess H3 which terminates at its lowermost point in a shelf-like portion IIG. Extending transversely of each of the horizontal side walls of housin is a plurality of spaced grooves H5 arranged such that corresponding grooves in each side wall are oppositely disposed for a purpose that will appear subsequently. In the lower portion of front wall H6 of the housing I69 is a pair of vertically spaced and threaded openings I E? which pairs are horizontally spaced as shown in Fig. 18.

The contact assembly of Fig. 15 i mounted in the lowermost portion of the housing I09 as indicated in Figs. 9 and 12. To accomplish this, the extreme left-hand ends of the screws Illl' are positioned in threaded openings III of housing I09. Also, each screw Iill is mounted in a tube N8 of electrical insulating material, Fig. 12. P- sitioned in each pair of aligned openings H5, Figs. 12' and 17, is an insulator strip H9 which serves normally to maintain associated contacts we and It'll of each pair out of engagement with each other, Figs. 15 and 16, and to control the movements of such contacts when engagement therehetween is being effected in a manner that will be presently explained. A cover I25, Figs. 9. l1 and 12, is pivoted on a pair of pins I2! secured by a drive fit in the uppermost portion of the two left-hand vertical uprights H2, Figs. 10 and 2.

The code box assembled as shown in Fig. '7 is inserted in the housing I22, assuming cover I22 in Fig. 12 to be rotated 9t degrees in a countor-clockwise direction, by lowering vertically from a position thereabove. In arranging the code box for such insertion, the tongue-like projections 32 of the code cards 88 are disposed on the left, and the label Top on the code box is in its uppermost position. As the code box it is being lowered, the individual contacts II project into associated aligned openings of the code cards 82. This continues until the lowermost edges of the four corners of the code box are seated on the shelf-like portions Ild, Figs. and 12. Now the uppermost portions of all contacts ill! are disposed slightly above the top of the code box 8 1, and the uppermost portions of all contacts I29 are positioned slightly therebelow. Fig. 12.

The under surface of the cover lid carries a pair of spaced gauges I22 which are arranged to seat on the uppermost surface of the code box 8 when the cover It!) is lowered and assuming the code box to be inserted properly into the housing its. This enables the cover I28 to attain the position shown in Figs. 9. 11 and 12. However, when the code box 2:! is improperly inserted into the housing I 99, the gauges I22 will so engage the in: errnost surface oi the code box as to prevent cover from reaching the closed position, Figs. 9, 11 and 12. Such insertion will be immediately indicated to the operator who will then proceed to make whatever adjustment of the position of the code box is necessary in order to bring about the position of the cover I28 as shown in Figs. 9, l1 and 12.

When the code box is properly inserted in the uprights I I2 as shown in Fig. 12 at least eighty of th individual contacts IEiI are out of engagement with the left-hand edges of the associated larger openings :23 of the code cards 89, Fig. 10, and at least ten of the individual contacts IElI are in engagement with the left-hand edges 10 of the associated smaller openings I25 of the code cards 80, Fig. 10.

In Figs. 11 and 12 a magnet coil I28 is suitably mounted at the center of the lower portion of the outer surface of the housing Hi5. Associated with this coil is the lowermost end of an armature I28 which extends upwardly in the form of a cross whose horizontal arms at their opposite ends are mounted on pivots I38. These are secured to a pair of spaced horizontal arms I3! formed integral with the respective horizontal sides of housing I853. The uppermost portion of the vertical section of the armature I29 terminates in a QQ-degree portion 532 extending inwardly towards the housing I09.

In Figs. 12 and 19 a screw I36 has its threaded end portion accommodated in a threaded opening I35 provided in a 90-degree portion I32 whereby the screw i3 lis vertically mounted thereon. On the upper end of screw I34 is positioned an angle member I36 whose function will be mentioned later. Immediately underneath this member is washer I37, and adjacent the opposite end of screw E34 is a further washer I38. Intermediate 1 these two washers is a bearing I39 which is freely rotatable on screw Ki l. A drum I46 is rigidly secured to the bearing I39 for rotation therewith. Intermediate the lower end of drum I48 and above washer I38 is a ratchet wheel IAiI secured to the drum for rotation therewith.

A flexible pawl I42, Figs. 12 and 19, is suitably mounted on the right-hand side of the front surface of the uppermost end of the vertical portion of armature I29, Fig. 11, so that its free end engages one tooth of the ratchet wheel Il. A flexible pawl I43 has its free end engaging another tooth of the ratchet wheel MI and its opposite end secured to one side of angle iron I44. This is secured to a transverse member I45 extending between the extreme left-hand portions of the two left-hand vertical uprights II2, Figs. 10 and 12, and is suitably attached thereto. A coiled spring I i-'5, Figs. 11 and 12, connects QO-degree portion 532 of armature I29 to a projection Ml formed integral with the mid-point of the uppermost portion of the front wall of framework I09.

A plurality of lugs I48 is spaced in helical fashion on the periphery of drum It!) such that individual lugs can be brought into alignment with individual code cards in code box 84 in a horizontal plane. The number of such lugs corresponds exactly with the number of code cards 88 included in the code box 84 so that one lug will be capable of engaging the tongue-like projection 82 of one associated code card 89 when the code box 84 is properly inserted in the U-shaped support IE9. For example, in Fig. 12, lug I48 engages tongue-like projection 82 on code card and actuates this particular code card in a right-hand direction. The larger openings I23 of code card 80' do not affect the positions or movements of the springs Elli projecting therethrough. However, the code card 86' at the left-hand edge of itssmaller openings I24, flexes in a right-hand direction. the upper ends of the associated contacts i-ill projecting therethrough and engaging therewith until the contacts ifll engage the contacts I20 associated therewith. Thus a circuit associated with each pair of engaging contacts I09 and -I III :is completed forza purpose that will become apparent later. As at least ten smaller openings are oontainedin each code card 80', this means that at least 1 3 discrete circuits will be completed.

When it is desired to complete circuits in ac- 11' r cordance with the smaller perforation I24 of the next succeeding code card in the code box, the magnet coil I28 is energized from a suitable source of electrical current, not shown. This causes armature I20 to rotate in a'co-unter-clockwise direction about its double pivots I30, against the force of coiled spring I45. This, as shown in Fig. 12, causes lug I43 to be withdrawn from engagementwith tongue-like projection 02 of code card Thereupon, code card 80' is caused to return to its normal position in code box 84 under the influence of the force exerted by the ten contacts Elli engaging the left-hand edge of the smaller openings I24 in code card 80'. At the same time pawl I43 actuates the ratchet wheel MI in a clockwise direction, Fig. 10, and thereby the drum I 40 in the same direction, or both of them in a counter-clockwise direction in Fig. 19, to bring the next succeeding lug into alignment with the tongue-like projection of the next succeeding code card. Pawl Hi2 engages the next succeeding tooth of ratchet wheel I4I to prevent further rotation of the drum I40 as armature I is rotated in the counter-clockwise direction. Fig. 19 shows the position of ratchet wheel I4I in its normal position, either after or before it has been stepped; and Fig. 20 shows the position of the ratchet wheel I il after being stepped once but is not yet returned to its normal position of Fig. 19.

When the energizing current for magnet coil I28 is interrupted, coiled spring I46 moves the armature in a clockwise direction to return the drum I to its normal position. Now, the next succeeding lug engages the next succeeding code card to move the latter to the right to accomplish the completion of ten further electrical circuits in the manner above explained regarding lug I 48 and code card 80. This operation may be repeated as often as desired so that each code card in the'code box may be used one or more times. In connection with the helical spacing of the lugs I48 on the periphery of drum I40, it will be understood that such spacing is So arranged that the lug associated with the top code card in the'code box comes into operative position after the lug associated with the last code card in the'code box has been operated. This permits a continuous selection of successive code cards. Obviously, such selection may commence and terminate with a preselected code on the drum I40 scraping along such projections as the code box 84 is being inserted into the U- shaped support I90 and/or removed therefrom. Such arrangement comprises angle member I36 positioned on top of drum I40 with its vertical portion in proximity of cover I20 but not in engagement therewith when the code box 84 is properly inserted in housing I 09 as shown in Fig. 12. However, when the code box 84 is to be removed, the cover I20 is rotated 90 degrees to the position illustrated in Fig. 21 at which position the inside surface of cover I20 engages both left-hand uprights H2. When necessary the inside of cover I20 can be built out by a liner I of appropriate thickness in proximity of each upright IIZ. In Fig. 21, cover I20'engages angle iron I36 in such manner as to tilt drum I40 in a counter-clockwise direction and thereby to disengage one of its lugs I48 from the tongue-like projection 82 of one of the code cards 80 in the code box 84. This obviates the danger of damage to the tongue-like projections on all code cards as the code box is raised and lowered in housing I09.

In the operation of Fig. 1, it will be understood that the individual code boxes i8 and I 9 are provided in accordance with the switching mechanism of Figs. 2 and 6 through 21, and. that the same or a difierent combination of code cards arranged in the same or a different relation is embodied in each of the code boxes. Referring to Fig. 1, it is indicated that, for the purpose of this explanation, stacks of code cards 00 and 80" are embodied in code boxes No. 1 and No. 2 respectively. In Fig. 1, for simplicity, code cards 80 and 80" from respective code boxes No. 1 and No. 2 are shown in their operated positions after being actuated,'by lugs 540 on drum I40 in the manner previously explained in left-hand directions as indicated'by the arrows at the lower edges of both code cards 80 and 80.

In Fig. 1 individual commutator segments I through 20 are connected to terminals I 03 each of which comprises an integral part of conductive member 98, Fig. 13. Thus, each vertical bar 98 in both code'boxes embodies ten electrical contacts IOI. Also, in Fig. 1, each horizontal column of each code box includes nine individual contacts I00, Fig. 14. A lead I50 connects individual reproducer magnets A I to all contacts I00 in one of the horizontal columns of such contacts. The actual connection of the reproducer magnets and commutator segments through the contacts I00 and MI will be clear from the diagrammatic illustration in Fig. 2, in

which the brush arm I I and magnetic tape I5 are connected by a shaft I0 for driving them.

As the coding is influenced only by the smaller perforations I24 only in the code cards as previously mentioned, engagement is effected in Fig. 1 between the precious metal contacts I04 and I06 of ten pairs of engaging contacts IOI and I00 respectively, in each of code boxes I8 and I9 as schematically illustrated by the solid dots. In Fig. 1 each reproducer magnet A I is connected to at least one odd numbered commutator segment and at least one even numbered segment, and at leastone reproducer magnet is connected to two different odd numbered segments and another reproducer magnet is connected to two' even numbered segments as indicated in the following table. This is generally illustrated in Fig. 2 with reference to code box I9 shown in Fig. 1, as above mentioned.

Reproducer magnet Commutator segment Obviously, one code box can be employed in Fig. 3, and four code boxes in Fig. 4.

Fig. 22 shows a code card selector adapted for manual operation, and is similar to the electrical code card selector of Fig. 12 except the magnet coil I28 and the lower portion of the armature l 28 associated therewith are eliminated, and in their places is substituted afinger grip II mounted on the top of drum I40. This .grip enables manual performance of the same function as that achieved by the magnet coil and armature operated thereby. Obviously, as in the case of Fig. 28, two or more code changing drums could be stepped by a single finger grip, or a single magnet coil and armature for that matter.

Figs. 23, 24 and '25 show a code card selector operated by a clock mechanism, otherwise the arrangements of these figures are identical with those illustrated in Fig. 12. Referring to Figs. 23, 24 and a clock mechanism I55 is connected to shafts I55 and I5! such that shaft 55 is continuously urged to rotate in a counterclockwise direction as indicated by the arrow but is permitted to rotate intermittently under control of a braking cam I58 which is keyed to the shaft I55 and whose operation will be described later, and such that the shaft I 51. is slowly rotated in a clockwise direction at a predetermined speed. The shafts I56 and I5! are driven by suitable coiled springs, not shown, embodied in the clock mechanism 155 and operating in the familiar manner. Wing nut I59 serves to wind such springs in the clock mechanism.

A U-shaped member I60 pivoted at I55 is disposed substantially in a vertical position, and embodies oppositely disposed vertical projections I62 and IE3 engageable with braking cam I58, and oppositely disposed vertical projections led and IE5 engageable with code changing cam 55 on shaft I51. Also mounted on this shaft but in an eccentric manner is a cam i 51. Engageable with substantially diametrically opposite portions of cam I61 are the adjacent free ends of a pair of leaf springs I68 and I59 whose opposite adjacent ends are fixedly mounted in U-shaped member I59 but on opposite sides of the pivot A gear lit mounted on shaft E56 engages gear IlImounted on shaft 912 on which member 513 is eccentrically mounted.

A collar 11s slidably positioned on eccentric member I13 is formed with an integral vertical projection I15 which terminates in a cylindrical portion I75, Fig. 23, provided with coaxial inr tegral shaft portions ill and 578a, Fig. 26. These portions extend coaxially from the opposite sides of portion H5. Rota-tably disposed on the free ends of the shaft portions Ill and ll'ea is the bifurcated end of a member H901, Fig. 26, pivoted at If! and carrying drum Mil, Fig. 24. lhis, as in the case of drum I Ml in Figs. 12 and 22, carries a plurality of spirally disposed lug I48, a ratchet wheel MI and pawls I 42 and I43 associated therewith.

In the operation of Figs. 23, 24 and 25, the clock mechanism I is arranged such that the shaft I51 rotates cam I66 through 186 degrees during a preselected period .of time. This causes the certain lug I48 on drum Me to select the code card 89' in code box 84 to perform a switching operation in the manner and for the purpose described hereinbefore in connection with Fig. 1 1. For example, the clock mechanism I55 can be adjusted to obtain a change of code cards 8 every fifteen or thirty minute period or other period, longer or shorten-as desired.

Referring to Figs. 24 and 27A, a U-shaped member IGI] is shown in the position resulting from its next previous operation due to cams I66 and I6! attaining certain rotary positions under control of clock mechanism I55 which is about to effect another operation of U-shaped member I55. The free end of leaf spring IE8 is flexed and under tension due to its resting substantially on .the highest peripheral portion of cam I57 relative to pivot I6! while leaf spring 59 is entirely disengaged from the latter cam. The force of the flexed leaf spring I58 tends to urge U- shaped member I60 in a clockwise direction but is precluded from doing so because its projection S55 is still resting on the higher peripheral surface of cam I56.

As the clock mechanism l55 rotates cam I55 to the position shown in Fig.2'7l3, projection IE6 is justraised to the higher peripheral surface of cam E55, and projection I65 is just dropped to the lower peripheral surface of cam Hit. This permits flexed leaf spring I68 to rotate U-shaped member ISO in a clockwise direction on its pivot 81. This disengages projection I52 from face lfil of cam I58 whereupon shaft I56 is permitted to rotate in a counter-clockwise direction and carry gear I15 with it in the same direction. This gear rotates gear MI in a clockwise direction as indicated by the arrow which rotation also moves shaft I72 in a clockwise direction. Now, eccentric member I13 is rotated in a clockwise direction in the collar I'M. This causes a substantially downwardly vertical movement of both projection I15 and its terminating cylindrical portion I75 whose shaft portions ill and Flt-a allow the bifurcated end portion of member I Isa, 'Fig. 26, to rotate thereon. The member i'IEa is now rotated in a counter-clockwise direc tion on its pivot IEI to move drum I iil away from the code box 84 in a vertical plan. This causes pawl M3 to actuate ratchet I iI and thereby rotate drum I45 in a plane perpendicular to such vertical plane until the next succeeding lug M8 is presented for engagement with the next succeeding code card 60 in code box 8:3 as hereinbefore explained regarding Figs. l2, l9 and 20.

Shaft I55 in Fig. 24 is permitted to rotate until face IBI of cam I53 engages projection I53 of U-shaped member I65 whereupon further rotation of shaft I55 is arrested. Due to a ratio of 2 to 1 between the number of teeth of gears HE! and I'll, these gears are rotated by the rotation of shaft I56 until the cylindrical portion I'lfi carrying the shaft portions Ill and Ilda, Fig. 26, attains its lowermost vertical position and thereafter is returned to the normal position shown in Fig. 24. During the time required for such movement of cylindrical portion N5, the member Ilsa is rotated in a counter-clockwise direction in a vertical plane to step the drum ME! one step, and thereafter in a clockwise direction in the same vertical plane to r turn the drum ltlil to the normal position of Fig. 24, and thereby to move the next succeeding code card in a horizontal plane as previously pointed out.

As clock mechanism I55 continuously rotates shaft i5l, cams I56 and l 51 are also continuously rotated until they attain the positions shown in Fig. 270 at which the U-shaped member IE0 is about to b operated again. Now the free end of leaf spring i139 i flexed and under tension due to its resting substantially on the highest peripheral portion of cam I61 relative to pivot IEI while leaf spring -!58 is completely disengaged from this cam. The force of flexed leaf spring use tends to urge U-shaped member I55 in a counterclockwise direction but is prevented from so doing

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