US2579101A

US2579101A - Telegraphic printing system

Info

Publication number: US2579101A
Application number: US779320A
Authority: US
Inventors: James A Spencer
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1947-10-11
Filing date: 1947-10-11
Publication date: 1951-12-18
Anticipated expiration: 1968-12-18

Description

Dec. 18, 1951 J, SPENCER 2,579,101

TELEGRAPHIC PRINTING SYSTEM Filed Oct. 11, 1947 3 Sheets-Sheet 1 INVEN'IFSR. JAM ES A. SPENCER ATTORNEY Dec. 18, 1951 J SPENCER 2,579,101

I TELEGRAPHIC PRINTING SYSTEM Filed Oct. 11, 1947 S Sheet's-Sheet 2 Q Fig.2

liq-3 Q I2 v JAMES A. SPENCER BY/ [M ATTORNEY INVENTOR.

Dec. 18, 1951 J. A. SPENCER 2,579,101.

TELEGRAPHIC PRINTING SYSTEM Filed Oct. 11, 1947 s Sheets-Sheet 5 SIGN/IL INPUT 4 I v ATTORNEY 4 y INVEN'I OR. 54 JAMES A. SPENCER Patented Dec. 18, 1951 TELEGRAPHIC PRINTING SYSTEM Alames .A. Spencer, .Teaneck, N. -J., assignrlto Radio Corporation of America, a corporation of Delaware 'Application"0ctober.11, 1947, SerialzNto; 79,320 20mins. (chive-135.)

Thepresent invention relates to telegraphic =printi ng .systemsandmore particularly to print- ,ingsystems based on the step-by-step method of transmission and reception. That is, the present.inventionis particularly directed to a ,printingsystem which :will produce, on a paper ,tape, --a printedmecord in .response to a series w-iofunequallength trains of signal reversals. Simvilar -s.tep,=by.-step..systems which have previously been developed. such-as )the .I-Iealy Stock Ticker land ,lBurry Printer, generally require auxiliary ,drivirig, .phasing and printing signals or equivalent expedients Whiohlincrease their complexity and cost.

'Thus, an object of the .present invention is to producea simple, low cos'tmachine capable of translating variablerlength trains of two .ele-

v.ment ,code .signals .into Zprinted .records without the,us'e .o'f special drivingor phasing signals.

Another object of the present. invention is the provision of .a simplified telegraphic printer which will operate .over long periods ,.of :time I, without ,,.requiring expert, attention.

.Still anotherobjectof the present invention iisthe provision of a telegraphic printer which. at each printing operation, automatically ,restores itself to a homing positiontfrom which position, all printing .operations are based.

Still another object of the present invention is the-provision of a telegraphic printer which .is adapted to be operatedby signals oflaohar- ,acter which may .be .transmitted over normally .unused facilities of a radio broadcasting system. Thus,the printer of the present invention may, for example, be coupled to a farmers radio broadcast receiver tuned to .a station transmitting marketingreports and allowed to operate ,:during the night. 'Thus, "the farmer is provided "with completemarket reports the first/thing in the morning sothat'he mayplan his days activities'intaccordance'jtherewith. Since in many 'suchcases -commercia1power lines are unavail- Jable, it is necessary that such a printer be independent of power ,line frequencies ,and that it require little electrical power for its. operation. The printer of .the ,present invention fulfills these requirements.

"The foregoing objects and others which may appear from theflfollowing detailed description :are-attainedby providing a telegraphic printer .iincluding .an,.ele.ctrome.chanica1 device ,for :ad-

vancing, a carrierlhaving character .indicia ,such as rotat n .a itxpewheellon a step-.Lby-stepv basis in ,response vto the .variableQ-length trains .of signal -reversals. ,A second electromechanical.

ilowerl contact spring leaf 2 4 moving its contact supporting lplate l2. by: resilient. material ;.acting to cushion the blow cofwthe stop member 22 striking th elstop '23.

v.meansis provided: forinitiating the printingppjeration, advancing the recording media and re- :setting the typewheel to a home position ,in

response .to aspacing signal of greater .time duration than-the normal spacing signal ele ments in=theitrains of signalreversals. .Thus,

.after ,printing each character, the printer is returned to ,a position of .rest forming a, base from :which .the next letter v.to be :printed .is

established.

Thepresent invention .willbe more fully understood by. reference .to ,the following detailed de- .scription which .is accompanied by a drawing in .which:

Figure 1 illustrates in elevational view an embodiment of .the present invention, while tonlof thearrows 4, 4 of Figure 2;

,Figure '5 is a fragmentary viewshowing, .in section, the spring return I for the typewheel of the device 'otFigurel, while I Figurefi is,an,electrica1 circuit diagram of the invention. I

Referring now to Figure .1 there is shown/a I base member generally indicated by reference character 10 carrying ,a vertical supporting plate l2 on whichismounted a typewheel.shaft;l4.

Shaft [4, as shown in more detailin the. section of1Figure,2, 'carriesa type carrier in the "form of a typewheell5 thereon. 'Typewheel, 15 is urged to a position of rest by spring l6 attached at -.one end to theghub l5 of typewheel l5 and at the other end to a spring barrel [8. As shown infidetailinFigure 5 spring barrel l8 issecure'd to the vertical support member IZ'by clamp dogs .I 9 and screws '20. By loosening screws :20 the spring barrel j'l8.m ay be rotated as desired-Yin order ,to .increasaor decrease the tension ;on

spring lfiacting \toreturn the typewheel :l5fto its'homing position. Typewheelhub I5 carries, in addition ,to ,.the typewheel, an operating ratchet'wheeli2l and a stop memberJZZ. ('Fig. 1).

.The typewheel is rotated by :a mechanismfto be described later, operating against ratchet wheel 2|. win :the position of rest the stop member}! bearsagainst a fixed stop '23 .mOunted. on the The stop may be .iaced TIfhestop pin,22 also, normally rests against the energized.

24 away from the contact carried by spring 25. These contacts are thus closed only while the typewheel is away from its home position. The contacts are thus shown in Figure 4.

A magnet 3|] having an armature 32 is mounted on the vertical supporting plate |2. The armature 32 carries a ratchet pawl 33 adapted to cooperatewith ratchet wheel 2|. When the magnet 30 is energized, armature 32 is attracted against the tension of spring 34, pressing pawl 33 against a tooth on ratchet wheel 2|, rotating it clockwise against the j,tension of spring I6. Pawl 33 wedges under a stop 35 at the end of its travel, jamming the ratchet wheel against further rotation and thus preventin overfeeding. A second pawl 36 engaging with ratchet wheel 2| and journalled on support 12 is provided to hold the wheel in its advanced position after pawl 33 is withdrawn by the action of spring 34 when magnet 30 becomes de- In order to prevent excessive rotation of the typewheel so that stop member 22 jams against the back of stop 23, one or more teeth may be omitted from ratchet wheel 2| in such position that excessive rotation is prevented. The angular movement of ratchet wheel 2| about the typewheel shaft l4 positions a selected one of the typefaces on the periphery of typewheel over a platen or print roller 40.

Recording media such as record tape 42 coming from reel 44 threads through guides 45 between the print roller and the typewheel l5, After passing through the second guide 45 the record tape passes between a pair of feed rollers 46 and 41. Tape feed roller 41 is carried by a pivoted carriage 49 and resiliently pressed against the feed roller 46 by means of spring 48. Feed roller 46 journalled on support Ratchet wheel 50 is adapted to be rotated by the action of pawl 5| l2 carries a ratchet feed wheel 50.

engaging the teeth on the ratchet wheel 50 as pawl 5| is moved by the operation of armature tape 42 against a selected type character on 'wheel |5 whenever magnet 54 is energized.

As shown in Figure 6 the Winding of magnet 54 is connected in series with the contact springs 24 and 25 and the armature 6| of a slow-torelease relay 60 to a source of potential as indicated by the plus mark. When the ratchet and typewheel occupies a homing position, the contacts carried by

springs

24 and 25 are separated and the circuit through the printing magnet 54 cannot be completed, whatever the condi-' tion of relay 60. The signal input is applied to a series circuit running through the winding of the slow-to-release relay 60, and the winding of the stepping magnet 30 to ground. The incoming selectin signals of the character indi-' cated at the upper left-rhand portion of Figure 6 are comprised of square wave impulses having .marking and spacing elements of approximately equal time duration. Relay 60 is adjusted to operate and open its contacts 6| in response to a single marking signal element and to remain operated for a period of time greater than that of one spacing element. Magnet 30 is adjusted to operate and release in response to the marking and spacin elements. The contacts carried by

springs

24 and 25 close as soon as stop pin 22 leaves its homing position against stop 23, so that whenever ratchet wheel 2| is advanced through the action of pawl 33 and armature 32 the printing circuit is completed from the moving contact of relay 65 through

contacts

24 and 25, through coil 54 to ground. Since the windings of relay 50 and magnet 30 are connected in series, the signals that actuate magnet 30 also actuate relay 60 to open its contacts. The relay 6|] being so adjusted as to release only in response to spacing elements existing for a time duration substantially greater than that of a normal spacing element, the printing circuit remains open .at the contacts of relay 60 during the reception of each series of selecting impulses. At the conclusion of each train of impulses, a spacing signal of substantially greater than normal time duration is received. The relay 6|] then releases and causes magnet 54 to be energized and initiate the printing operation. The energization of magnet 54 causes the tape roller 40 to press the record tape 42 against the selected one of the type characters on typewheel |5. The operation of armature 52 likewise causes pawl 5| to be stepped upwardly one tooth on ratchet 50. The printing operation also causes locking pawl 36 to be withdrawn from ratchet wheel 2|, allowing the typewheel to return to its home position. The stop 22 striking contact sprin 24 opens the printing'circuit and allows armature 52 to fall back. The return of armature 52 to its normal (at rest) position, rotates the tape feed roller 40 to advance the record tape to a new printing position. 7

The type on print roller I5 is preferably arranged in accordance with the frequency of occurrence of letters in the type of messages most likely to be transmitted so that a minimum number of selecting impulses is required for the most commonly used letters. The typefaces may be inked by an inking roller 10 carried by a pivoted carriage urged against the typewheel by gravity or a light spring if desired. Alternatively, a strip of carbon paper may be carried along with, but preferably at a slower rate than, the record tape 42. I

While I have illustrated a particular embodiment of the present invention, it should be clearly understood that it is not limited thereto since many modifications may be made in the several elements employed and in their arrangement and without departing from the spirit and scope of the invention.

What is claimed is:

1. A teleprinter including a typewheel having printing characters on its periphery, a record tape, resilient means for urging said. typewheel to a predetermined home position,. a ratchet wheel carried with said typewheel, signal input means and a series circuit across said signal input including a signal responsive magnet and a sloW-to-release relay,. a pawl actuated by said magnet and engaging said ratchet so arranged as to step said typewheel away from its home position in response to signal impulses applied to said input means, a printing bar and electro-magnetic actuating means for said printing bar, a circuit including a back contact of said slow-to-release relay and its armature, a pair of contacts adapted to be closed by movement of said typewheel away from its home position and said electro-magnetic actuating means, said slow-to-release relay closing said circuit in response to cessation of each train 'of signal impulses whereby said printing bar is actuated, means responsive to actuation of said printing bar for releasing said typewheel for return to its home position and means responsive to the release of said printing bar for feeding said record tape, said last mentioned means including a feed roller for said record tape, a ratchet on said feed roller and a feed pawl adapted to engage said ratchet and operated by said printing bar.

2. A teleprinter including a typecarrier having type faces arranged in sequency thereon, a recording medium, resilient means for urging said typecarrier to a predetermined position, a ratchet carried with said typecarrier, signal input means and a series circuit across said signal input including a signal responsive magnet and a slow-torelease relay, a pawl actuated by said magnet and engaging said ratchet so arranged as to step said typecarrier away from its home position in response to signal impulses applied to said input means, a platen and electromagnetic actuating means for said platen, a circuit including a back contact of said slow-to-release relay and its armature, a pair of contacts adapted to be closed by movement of said type carrier away from said predetermined position, and said electromagnetic actuating means, said slow-to-release relay closing said circuit in response to cessation of each train of signal'impulses whereby said platen is actuated, means responsive to actuation of said platen for releasing said tpyecarrier for return to said predetermined position and means responsive to the release of said platen for feeding said recording medium, said last mentioned means including a feed roller for said recording medium, a ratchet on said feed roller and a feed pawl adapted to engage said ratchet and operated by said platen.

JAMES A. SPENCER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 139,128 Edison May 20, 1873 273,810 Burnside Mar. 13, 1883 1,291,836 Harris Jan. 21, 1919 2,353,673 Kennedy July 18, 1944 2,388,733 Fischler et al Nov. 13, 1945