US2498724A - Telegraph transmitter - Google Patents

Description

1950 A. E. THOMPSON ETAL 2,498,724

P SMITTER Patented Feb. 28,1950

TELEGRAPH TRAN SMITTER Alfred Edward Thompson and Reginald Dennis Salmon, Croydon, England, assignors to International Standard. Electric Corporation, New York, N. Y., a corporation of Delaware Application May 23, 1947, Serial No. 750,108

In Great Britain June 13, 1941 Section 1, Public Law 690, August 8, 1946 Patent expires June 13, 1.961

I This invention relates to telegraph transmitter's.

I Start-stop teleprinter systems commonly employ keyboard-controlled signal transmitters. Under some conditions, as, for example, in aircraft, it is difiicult to operate a keyboard; the operator may be wearing thick gloves and consequently will not be able to select and depress individual keys without, at the same time, partially depressing others. In other circumstances, it may be necessary for personnel untrained in the use of a keyboard to transmit messages. It is, therefore, the purpose of this invention to provide means whereby telegraph signals may be transmitted by unskilled personnel and without .the use of a keyboard. It is a particular object of the invention to provide means whereby startstop teleprinter signals may be transmitted withoutthe use of a keyboard. i The nature of the invention is particularly devscribed and ascertained in the following descrip- "tion of one, embodiment thereof taken in conjunction with the accompanying drawing.

Claims. (Cl. 178-80) Referring to the diagram, a start-stop teleprinter'transmitter is provided of the kind described'in British Patent No. 315,244 and having keybars I controlling combination bars 2 in the normal manner. Guiding rail or rails I are mounted in a framework, not shown, above the teeth between each slot being cut in the form of a knife-edge, there being one slot corresponding to each keybar. The chariot carries a pivoted frame 4, which extends in a ,forward .and downward direction and terminatesin'a' handle 5, formed to a shape convenient for the grip of the operator. The frame is provided with a knife-edged extension 4a adapted to co-operate with the corrector bar. The frame'is provided with an extension 3, adapted to engage with any keybar above which the frame may be brought. The frame is provided with extensions Ma and Nb, adapted to co-operate with arms In and I2?) when the frame is brought over the figure or letter shift keybar. A spring 4b is provided holding the frame 4 in an upper position so that the knife-edge extension 3 is held clear of the corrector bar I5.

The chariot also carries a pointer or cursor 8,

adapted to move in front of a cylinder 9, upon which are inscribed the letters of the alphabet and other characters, arranged so that, in the first and third quadrants of the cylinder, letters appear while in the second and fourth quadrants other characters, for example, figuresjand conventional signs, appear, the characters in the opposite quadrants being the same.

The cylinder may be viewed through a window so that only one quadrant is visible atany one time, the pointer or cursor being seen through the window. The cylinder is mounted in the frame.- work, so that it may be rotated to bring either the' letter or figure set of characters into view, as required. Forthis purpose, the cylinder carries at one end a toothed ratchet Illa, and at the other end, mounted at right angles to Illa, the two-toothed ratchet I012. The pawls Ha and MD are arranged to rotate the cylinder through one-quarter of a revolution, when the arm I2a or I'll) oftoothed sector I3a or [3b is depressed. In the position shown, whenthe chariot is moved so that figures appearsto view in the cursor, the extension Ma is brought over the arm 12a. When the handle is depressed, the downward movement of extension I la will rotate arm I2a about its pivot, andsector I30; will cause pawl l Ia, to rotate the drum through one-quarter of a revolution and bring the figure set of characters into view. I Y g A spring is attached to sector l3a to restore this sector and pawl I Ia to initial position when the handle is raised.

When the cylinder has been rotated to the figures position, further depression of the handle,

when the frameis over the figure shift key, will not cause the cylinder to revolve, since the ratchet .teeth I 0a are now a quarter of a revolution out of phase. The teleprinter transmitter will, however, transmit the start-stop code signal for figure shift. The ratchet teeth IIlb are now in such position that pawl I Ib engages with one of the teeth. .When the chariot is moved so that letters? appears'to view in the cursor, the exand exactly positioning the chariot in an endwise position.

Further downwardmovement of the handle causes the extension 3 to depress the ,keybar above which the frame has been brought, thus causing the teleprinter transmitter to be operated in the normal manner and transmit the startstop signal corresponding to the character selected. Means are provided as usual in the teleprinter transmitter whereby the combination bars are locked, so that they cannot be moved into another position until the teleprinter signal has been transmitted. When the handle is moved to bring the cursor opposite either the letter shift or figure shift, the depression of the handle causes the transmission of the figure or letter shift signal and, at the same time, will rotate the cylinder to the shift selected unless the cylinder was already in the shift selected, in which case it will not revolve.

The handle is not locked in its downward position while the teleprinter signal is being transmitted, but is free to rise and be moved into the position corresponding to the next character required. It cannot be depressed again, however, until the transmission of the first signal is completed, because all thekey bars are locked against operation during this ,period.

What is claimed is:

1. In a telegraph transmitter, in combination, a teleprinter base having .a plurality of substantially parallel key bars and combination bars selectively displaceable on depressing any of said key bars, said combination bars being adapted to efiect the transmission of a signal in teleprinter .code corresponding to the key bar depressed, said key bars including first and second shift bars adapted to cause the transmission of a first and second shift signal, respectively, a chariot movable transversely of said key bars, guide means slidably supporting said chariot, a lever extending from said chariot above said base, said lever having an extension positionable adjacent a selected key bar and-being actuatable to depress a key bar thus selected 'bymeans of said extension, a roller extending along the path of travel of said chariot, said roller bearing character indications in at least two angularly spaced rows, a cursor displaceable with said chariot to indicate on said roller a character corresponding to the key bar selected, and mechanism actuatable by said lever upon engagement of either of said shift bars for rotating said roller so as to bring arespective row of characters into alignment with said cursor.

2. The combination according to claim 1 wherein said roller bears at least four rows of characters, one in each quadrant, the characters in opposite vquadrants'being identical, and wherein said mechanism is arranged to rotate said roller in one direction only'regardless which shift 'bar has been selected.

3. The combination according to claim 2 wherein said mechanism comprises two pawl-andratchet'a'sse'mblies each effective to displace said roller by substantially 90 degrees only, in response to selection of a respective shift bar, said two assemblies being staggered by 90 degrees.

' Number 4. A telegraph transmitter comprising a phirality of substantially parallel key bars, a plurality of combination bars selectively displaceable on depressing any of said key bars, said combination bars being adapted to efiect the transmission of a signal in teleprinter code corresponding to the key bar depressed, said key bars including a figure shift bar and a letter shift bar adapted to cause the transmission of a figure shift signal anda letter shift signal, respectively, a chariot movable transversely of said key bars, guide means slidably supporting said chariot, a lever extendin from said chariot above said key bars, said lever having an extension positionable above a selected key bar and being actuatable to depress a key bar thus selected by means of said extension, a corrector bar extending along the path of travel of said chariot, said bar having' teeth adapted to cooperate with said lever so as accurately to locate :the latter with respect to a selectedkey bar, a .roller extending along the path of travel of said chariot, a cursor mounted on said chariot for indicating on said roller a character corresponding to the key bar selected, said characters comprising identical rows of letters in the first and third quadrant of said roller and identical rows of figures in the second and fourth quadrant thereof, a first and a second ratchet each secured to said roller and having two teeth 180 degrees apart, the teeth of said ratchets being staggered by degrees, first and second paWls cooperating with said ratchets,respectively, and arms on said lever adapted to engage said first and second pawls', respectively, when said extension is aligned with a respective one of said shift bars, whereby said cursor 'will'be brought into alignment with either letters or figures on said roller depending upon the shift bar selected.

5. The telegraph transmitter according to claim 4 wherein said'shift bars are'the two'extreme key bars, said ratchets being mounted at opposite sides of said roller on a common shaft therewith.

ALFRED EDWARD THOMPSON. REGINALD DENNIS SALMON.

REFERENCES CITED The following references .are of recordin the file of this patent:

UNITED STATES PATENTS Name Date 432,453 Taylor July 15,1890 1,056,269 Fastnacht Mar. 18, 1913 2,085,609 Schonfelder June 29, 1937 2,169,158 Miller Aug. 8, 1939 2,406,865 Thompson et a1. Sept. 3, 1946 FOREIGN PATENTS Number Country Date 549,978 Great Britain Dec. 12, 1942

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