US2420802A - Selective-speed telegraph code instruction system - Google Patents

Description

May 20, 1947. o. THOMPSON SELECTIVE-SPEED TELEGRAPH CODE INSTRUCTION SYSTEM Filed. NOV. 14, 1942 TONE INPUT DUDDDDIJUDUU XMM Oraz'lle J. Tfzom 5027/ Ms Ufa/away Patented May 20, 1947 SELECTIVE-SPEED TELEGRAPH CODE INSTRUCTION SYSTEM Orville I. Thompson, Chicago, 111., assignor to De Forest's Training, 'Inc., Ghicago, 111., a corporation of Illinois Application November 14, 1942, Serial No. 465,596

ticularly to an apparatus whereby a plurality of code speeds may be automatically transmitted simultaneously by a single sending unit.

It is a principal object of this invention to provide a manifold code speed transmission device which is simple in construction, economical in manufacture and highly efiicient in use.

Another object of this invention is to provide a single signal bearing means bearing a plurality of signals at graduated speeds and operative by a common drive for simultaneously transmitting a plurality of signals each at a different ratio of words per minute.

A further object of this invention is to provide a device on which the sound of code characters can be made the same for a wide range of code speeds.

Other objects and advantages of the invention will appear hereinafter.

The invention consists in' the novel combination and arrangement of parts to be hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawings showing the preferred form of construction, and in which:

Fig. 1 is a schematic diagram of a multi-speed code sending system embodying my invention;

Fig. 2 is a fragmentary perspective view .of a gang sound-sensitive unit embodied in my invention;

Fig. 3 is a fragmentary vertical sectional View through a drive means and associated parts embodied in my invention;

Fig. 4 is a fragmentary vertical section through an individual signal detector device employed in my invention;

Fig. 5 is a view of a portion of signal bearing tape illustrating the graduated signallimprinted on the tape; and

Fig. 6 is a schematic diagram of another form of signal distributing system which may be used with my invention.

Heretoforein thepractice of code instruction,

various types of automatic senders have been used whereby to transmit code messages :from a code bearing strip 1 or :drum :to receiving stations.

However, all existing automaticsenders are'limited to the sending of a single message and are set to a desired speed by the driving means for the code bearing members. Such devices are best represented by the disclosure in Patent No. 2,284,024 issued May 26, 1942, to Stevens on Tape actuated reproducer, etc. These former automatic senders required a separate drive and an individual code bearing tape for each of the code speeds, which, for example, might range from six to sixty words per minute at two-word intervals, thus requiring separate sending units in an instructionsystem in order that all code speeds might be available for sending simultaneously during a course of instruction.

This invention contemplates the provision of an. automatic code sending apparatus whereby the full range of code speeds will be automatically transmitted simultaneously by the use of a multitracked tape driven by a single drive means. In carrying out the invention 1' provide a frame structure Ill upon which is mounted a motor H or any other suitable power transmission means. A drive shaft I2 extending from the motor I! has bearing in the frame It and carries on its outer end for rotation therewith a reel or spool [3 on which a web M in the form of transparent tape may be wound. A feed roller l5 in the form of a reel is mounted on the frame Ill through the medium of a shaft l6 carried by the frame l G and has wound thereupon the web [4 for feeding the latter in accordance with the speed of the reel I3 under power of the driving motor ii.

Arranged between the feeding roller l5 and the driving reel [3 is aninsulated panel H which is supported upon brackets I8 attached to the frame [0; this panel supports a plurality of light-sensitive units l9 which correspond in number to the number of different speeds of message to be transmitted. It is apparent that any numberof units I9 may be employed and, as heretofore explained, that the range may be from six words per minute on up, at varied intervals of words per minute. However, for the present description only five units I9 are shown to illustrate the principle of the invention.

Each light-sensitive-unit L9 comprises a socket '29 mounted upon the panel [fl-to disposea-receiving seat :2I on. the side of the panel so to laterally support, a photo-electric cell the plane of movement of theweb Mr'frcm'faading roller to driving roller l3. Each unit [9 is completed by having a tubular light shield 23 arranged on the socket 20 to surround the respective photo-electric cell 22'. As shown in the drawing, the light-sensitive units are arranged with their centers spaced equidistant on a segmental arc and thus together form a guideway over which the web l4 may be trained. A floating sprocket 24 is arranged on the frame II] for rotative movement adjacent the feeding roller I and is adapted to guide the web M from a uniform position over the light-sensitive units I9, the web traveling around the guideway formed by the units onto another floating sprocket 25 which is carried by the frame If) and acts as, a tensioner for the web 14 to assure at all times that it will cling to the light-sensitive units for reasons hereinafter to become more apparent; the web finally being aflixed to the driving reel I3 in a Well-known manner, the reel l3 being driven by motor H to pull the web over the aforesaid train of movement.

In carrying out the principle of this invention, I provide the web M with a number of tracks 26 which correspond in number with the number of speed variations desired. Each of the tracks 26 comprises a message in code by printing, perforating or otherwise marking the hieroglyphics of the code along the tracks. As shown in Fig. 5, the web l4 comprises a Celluloid ribbon having eight different tracks 26 each bearing a message. In this form of web the message is recorded by photography, and while this is a very practical method of recording the messages on the web, it is essential to this invention that the production of the code on the web be done at a fixed linear speed but in a manner to render each track 26 a different code speed with respect to each other. Thus, as seen in Figs. 2 and 5, the same code character starting from a fixed point on the web will be of increased spacing along its respective track in proportion to the ratio of number of words per minute. The lowermost track 26 (Fig. 5) represents a code message which will bear six words requiring a minute of travel of the web to pass a fixed point. Each track from bottom to top increases in speed by a speed of two words a minute so that the uppermost track 25 represents a code speed of twenty words per minute of travel of the web past a fixed point.

Thus, as seen in Figs. 2 and 5, the code characters remain-the same but the characters of one track 28 are spaced from succeeding characters a greater or lesser distance with respect to the spacing of characters on adjacent tracks, thus assuring at all times that each character, regardless of whichever sound track it be on, will be of a constant phonetic pitch. In former type tapes with a single track, a change of speed of travel of the tape although changing the number of words per minute in transmission had the undesirable characteristic of likewise changing the tone pitch of eachcharacter. Since it is important that the student at an early state become accustomed to the uniform tone pitch at which telegraphic code is transmitted it is a great advantage that he receive the message at such uniform tone pitch at a greater or lesser number of characters per minute. It is therefore obvious that in the present invention it is an advantage in having numerous tracks with characters each of which will transmit a constant tone value regardless of the number of words transmitted per minute.

Each of the light shields 23 has an aperture 21 formed therein in its side wall along which the web [4 travels. When considering the lightsensitive units as a gang as shown in Fig. 2, each aperture 21 is spaced relative to the aperture 2'! of the adjacent unit l9 a distance corresponding to the distance between tracks 26 on the Web Id. In this manner each track 26 cooperates with its respective aperture 21 to affect a separate light-sensitive unit. In conjunction with the apertures 21 and code tracks 26, there is a light source 28 arranged on a bracket 29 carried by the frame Ill. A reflector 30 shields the light source 28 but permits the light to be reflected in the direction of the apertures 21 so that when a clear image is presented on the track 26, light will impinge upon the photo-electric cell 22 to excite electronic activity within the cell 22 to permit an impulse to bridge the anode and cathode of the cell 22.

As shown in Fig. 1 of the drawing, each photoelectric cell 22 is arranged in a block grid keying tube circuit 3! in a manner such that when an impulse is permitted to pass through the cell as aforesaid, a blocking tube 32 is caused to operate, which operation will permit transmission of the signal to head phones Each circuit is provided with a commutator switch 34 whereby the different photo-electric cells may be thrown in circuit with a particular receiving set. As illustrated, station "1 on the left of Fig. 1 is connected in circuit with the lowermost photoelectric cell 22 and is receiving the slowest message from the web, while station 5 is receiving the fastest message, all of which is governed by the position of the pointer on the commutator switch 34.

In Fig. 6, a similar circuit may be employed; however, in this system the blocking or keying tubes are all built in a single unit 35 each having a series of jacks 36 whereby plugs 31 from the receiving stations may be plugged in to connect such stations to the photo-electric cell of the code speed desired.

It is obvious that various forms of circuits may be employed and that they may be amplified depending upon the form of reception desired, the main purpose being to pick up the message in a manner to carry out my invention of producing the simultaneous transmission of several code messages at different code speeds from a single automatic code sender.

While I have illustrated and described the preferred form of construction for carrying my invention into eifect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claim.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

A device of the class described comprising a plurality of independently operated receiving stations, means for transmitting a plurality of code messages, means for connecting said receiving stations to said transmitting means for the transmission by said transmitting means to one or more of said receiving stations of a selected one of said code messages, said code messages varying in speed by a single drive means, said transmitting means including a plurality of message transmitting units arranged adjacent each other to form a guideway, a web arranged for movement over said guideway, a plurality of message tracks REFERENCES CITED formed in said web and spaced relative to each The following references are of record in the othe}:s transversely of said web, said message file of this patent:

trac being made up of code characters with 5 the message tracks varying in characters per UNITED STATES PATENTS length of said web with respect to each other, Number Name Date means on said message transmitting units for 680,695 Comins Aug. 20, 1901 communicating a particular one of said message 1,804,136 Wright May 5, 1931 transmitting units with a particular message 10 2,284,024 Stevens May 26, 1942 track, and drive means for moving said web rela- 1,848,799 Papalia Mar. 8, 1932 tive to said guideway. 1,962,467 ShOlkin June 12, 1934 ORVILLE I. THOMPSON. 1,950,011 Soheibell Mar. 6, 1934

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