US2772878A - Device for advancing tape records in telegraph apparatus - Google Patents

Description

1956 H. WUSTENEY ETAL 2,772,878

DEVICE FOR ADVANCING TAPE RECORDS IN TELEGRAPH APPARATUS Filed Oct. 9, 1952 Jizoavgfors. ufzrea Jam /77% Jazzder; 5

1906651 J enw.

DEVICE FOR ADVANCING TAPE RECORDS IN TELEGRAPH APPARATUS Herbert Wiisteney, Munich-Thalkirchen, Josef Bauder,

Munich-Solln, and Robert Stabenau, Berlin-Spandau, Germany, assignors t Siemens & Halske Aktiengeselischaft, Berlin and Munich, Germany, a corporation of Germany Application October 9, 1952, Serial N 0. 313,962 Claims priority, application Germany October 29, 1951 2 Claims. (Cl. 271--2.4)

This invention is concerned with a device for driving the record tape in telegraph transmitter apparatus.

The drive for advancing the record tape is in known telegraph transmitters usually accomplished by a device comprising a toothed wheel which is driven in step-bystep manner by a drive wheel disposed on the same shaft. This known tape drive includes a relatively great mass which is set in motion incident to each advance of the tape. The resulting forces operate to the detriment of .the operating speed and cause wear of associated parts.

The purpose and object of the invention is to simplify the device for advancing the tape and to reduce the masses that have to be set in motion. This object is realized by .the provision of a toothed wheel which is rotatable on a fixed shaft and operable by a pawl. directly actuated by .a'cam disposed on the drive shaft of the transmitter. .Resiliently operable brake means is provided for holding the toothed wheel in any angularly set position.

The device according to the invention has a minimum of mass that has to be set in motion, thereby reducing the material costs, simplifying adjustments, stepping up the operations, and securing in addition relatively noiseless operation due to the resilient action of the brake means on the toothed tape drive wheel.

The pawl for advancing the tape drive wheel is in accordance with another feature of the invention operative at the roots of the teeth thereof, thereby preventing damage to the tape record which is usually made of paper and also avoiding deformation, by the action of the pawl,

of the free ends of the teeth of the drive wheel where they engage the perforations of the tape.

An embodiment of the invention will now be described with reference to the accompanying simplified and diagrammatic drawing wherein Fig. l ShOWs the new tape drive device in simplified perspective view; and

Fig. 2 indicates on an enlarged scale the coaction of the pawl with the teeth of the drive wheel and of the latter with the tape.

Referring now to the drawings, the drive wheel 1 for advancing the record tape 2 is freely rotatable on the fixed shaft 3 and is in step-by-step manner advanced by the pawl 4 by direct engagement of the pawl with the teeth thereof. The pawl 4 is pivotally mounted on the lever arm 4a and biased angularly in the direction of the drive wheel 1 by a spring 15. The lever arm 4a is adjustably mounted on the left hand arm of the elbow lever 5 for the purpose of adjusting the position of the pawl 4 with respect to the drive wheel 1, thus determining the correct position of the tape 2 relative to the scanning means (not shown). After the position of the lever arm 411 has been adjusted on the left hand arm of the elbow lever 5, the adjustment is tightened to secure the lever 4a in fixed connection with the elbow lever 5. The pawl 4 is driven by the elbow lever 5 which is pivotally journalled at 8 and actuated by the cam 6. The cam is disposed on the shaft 7 which may be the drive shaft of the transmitter. The means for rotating the shaft do not form part of the invention and therefore have been omitted. Incident to each rotation of the shaft 7, the cam 6 will press against the downwardly extending limb of the elbow lever 5 to rotate such lever clockwise again-st the pull of the spring 9 extending from the lever arm 4a. The generally horizontally extending left hand limb of the elbow lever 5 will accordingly move upwardly against the pull of the spring 9 on the intermediate lever arm 4a which links the elbow lever with the pawl 4. The pawl will respond and move upwardly to advance the drive wheel 1 counterclockwise by an increment corresponding to one or more teeth, thereby correspondingly advancing the record tape 2. The drive wheel 1 is in this manner advanced incident to the feeding stroke of the pawl 4. The return motion of the pawl is prompted by the pull of the spring 9 responsive to further angular rotation of the cam 6. The elbow lever 5 and with it the intermediate lever 4a are rotated counterclockwise, carrying the pawl along. The operative end of the pawl glides along the next successive tooth on the drive wheel 1 into position in back of such next successive tooth. The relatively slight frictional force exerted by the pawl 4 on the corresponding tooth of the drive wheel 1, during the return stroke, is insufficient for rotating the drive wheel which is held by the brake members 10 and 11 in a manner which will be presently explained.

If desired, suitable means may be provided for guiding the displacement of the pawl. Likewise, if desired, the intermediate arm 4a to which is attached the spring 9 may be omitted and the pawl 4 may be directly linked with the horizontally extending limb of the elbow lever 5. The spring 9 may in such a case exert a force on the elbow lever to bias it counterclockwise. means may be provided where desired or required.

Brake blocks 10 and 11 are provided for holding the drive wheel 1 in any angular position. The brake blocks are made in the form of striplike members so as to leave space between these blocks and the punched record tape for the scanning levers (not shown) which coact with the tape. The rearwardly disposed b-rake block 11 is stationary, e. g., disposed in a recess in the apparatus housing or a suitable structural part. The frontally disposed brake block 1% is provided with a V-groove 13 which is engaged by the similarly shaped end 14 of the leaf spring 12, the lower end of which isfixedly secured as shown. The leaf spring presses resiliently against the brake block 10 which in turn presses the drive wheel against the coacting brake block 11. Suitable means, not shown, may be provided for guiding the movable brake block 14 The drive wheel 1 is by the action of the brake blocks retained in any angularly advanced position incident to the return motion of the pawl 4 responsive to the action of the spring 9 and, as explained before, the slight frictional force exerted by the pawl 4 on the next successive tooth of the drive wheel, incident to its return stroke is thus unable to rotate the drive wheel.

It will be seen from the foregoing explanations that the drive Wheel 1 and therewith the record tape 2 are actuated directly by the operation of the cam 6. The pawl 4 is actuated without shocks and the teeth of the drive wheel as well as the record tape 2 are protected against damage. The record tape 2 may therefore be made of the relatively low grade paper stock even if it is intended for repeated use. The masses which are displaced are very small and the speed of operation may accordingly be increased.

The tape is guided through an arcuate path as shown in Fig. 2 so that several teeth 16 of the drive wheel always engage several tape perforations 19. This feature assures the reliable advance of the tape while protecting it against Suitable stop 3 damage. F'The tape Zrnoves'through the arcuate path between afi-xe-dguide -17 and a suitable retainer -18 which may be pivotally mounted to facilitate insertion of the tape.

It-will also bejs'een fromFigfZ thattheflctuatirrgend of'thepawlfl engages the drive Wheel at the-roots of the teeth 16. Theteeth are'at the point of engagement with the pawl fo'r'rnedflat so as to minimize the inevitable wear. The free ends of the teeth which engage the tape perforations'are'rourided to' facilitate the transport of the tape and thesafe' engagement of the teeth with the perforations thereof. These free ends ofthe teeth 16 cannot be deformed or in any way damaged by the actuation of the pawl 4. The tape is therefore protected.

The inventionis particularly adapted forthe specific use in telegraph transmitters as described, but may of coursefind'use in other or'related type of apparatus within the scopearidspititof the appended claims.

We claim:

1. In a'telegraph apparatus having a perforated tape, a device for advancing said tape step-by-step and for controlling and securing the stepwise advance thereof substantially free of blacklash, said device comprising a stationary shaft, a sprocket wheel freely rotatable on said shaft, said sprocket wheel having teeth for engaging perforations in said tape, a pawl disposed alongside said sprocket wheel, means for resiliently biasing said pawl in a direction radially inwardly of said sprocket wheel to cause the free end thereof to assume a normal position between-two adjacent'sprocket teeth, means for reciprocatingsaid pawl to impart thereto successive drive strokes during each of which said pawl exerts a driving force on a sprocket tooth engaged thereby so as to rotate said sprocketwheel by one step and-to advancesaid tape accordingly, said pawl slidingduring the return stroke thereof along a sprocket tooth to its normal position from:

which it issubsequently moved to executethe next successive drive stroke thereby exerting a force on said. sprocket wheel tending to rotate it in opposite backlash. direction, and a movable generally semicircular general-- ly flat brake member in resilient frictional engagementv with one side of said sprocket wheel along an area there- References Cited'in the file of this patent UNITED STATES PATENTS 479,659 Pierce July 26, 1892 621,277 Parsons Nov. 16, 1897 593,686 Peckha'm Mar. 14, 1899 950,473 Campbell et al. Mar. 1, 1910 1,174,236 Dixon Mar. 7, 191.6 1,436,706 'Galarnb Nov. 28, 1922 1,780,194 'Kend'e Nov. 4, 1930 1,882,014 Howell Oct. 11, 1932 2,102,860 Stoner et al Dec. 21, 1937 2,277,134 Nelson Mar. 24, 1942 2,389,929 Paulse'n Nov. 27, 1945 2,398,733 Wenz'el Apr. 16, 1946 2,404,339 Zenner July 16, 1946 2 ,643,114 Laskey June 23, 1953

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