Patent GB-806392-A (GB)
Title: Transmitting mechanism for teleprinters
Inventor: ROSENDAHL GUNNER JULIUS JOHANN
IPC: H04L17/06
Filed: 1956-08-13
Abstract: 806,392. Printing telegraph transmitters. STORE NORDISKE TELEGRAF-SELSKAB A.S. Aug. 13, 1956 [Sept. 28, 1955], No. 24697/56. Class 40 (3). In a start-stop printing-telegraph transmitting mechanism in which at least one contact member is operated by the action of spring-operated sensing members released sequentially by cams on a rotating shaft to be advanced towards corresponding selecting members selectively set according to the elements of a signal to be transmitted, in which the contact member is constantly urged by a spring to one of its operating positions, and in which springs cooperating with the sensing members are arranged to move the contact member to its opposite position against the action of the first-mentioned spring when the movement of the sensing member is unimpeded by the associated selecting member a multi-toothed cam on the rotating shaft determines the instants for switching said contact member and a locking member driven from said cam retains the contact member until the spring action which is to be effective for the next following position of the contact member has been determined by the sensing members. The contact - operating member comprises springs 30 secured to a block 32 and carrying conducting studs 34 engaging lower or upper contacts 36. The ends of the springs 30 are held in a recess 38 of a member 40 mounted on a shaft 50 and provided with an arm 42 normally biased by a spring 48 against a stop 44 so that the lower contact 36 is engaged by a stud 34. The arm 42 is formed with a cross-piece 52 engaged by the lower part of a start element lever 24 and the downward extensions of five sensing levers, of which the 1st and 3rd, 24a and 24c, are shown, the six levers being biased in an anticlockwise direction by springs 28 and having projections 26 engaging sequentially arranged recesses or flats 16 of a start cam 14, and five cams of which 14a and 14c are shown. The member 42 is held in the position to which it has been moved and the lengths of the signal elements transmitted are controlled by the engagement of an extension 54 with the projection 56 of a pivoted latching lever 58 having a downward extension 66 engaged by a bent-up portion of a lever 74 pivotally mounted on an arm 68 having an extension engaging the five lobes 20 and a sixth lobe 201 of a multi-toothed cam 18 mounted on the shaft 12. On the depression of a key for the transmission of a signal, the shaft 12 is set into rotation and subsequent to the movement of a flat 16 to a position opposite the projection 26 the inward movement of lever 68 rocks the member 58 so that the latching projection 56 is raised. The projection 26 engages the recess or flat 16 of the cam 14 so that the lever 24 is rotated by its spring 28 which overcomes the action of spring 48 and rocks the arm 42 against the stop 46 so that the contact 34 is moved to engage the upper contact 36 to send the start element. The selecting members are selectively set with their ends in upper (full line) or lower (broken line) positions. In the upper positions 10a . . . 10c . . . , the ends of the associated sensing levers 24a ... 24c are unimpeded and when their projections 26 are opposite the recesses 16 of the cams 14a, 14c with the subsequent operation of the lever 68 to raise the latching projection 56, the spring 28 moves the lever 42 to the right to send a negative or spacing element. When a selecting lever is in its lower position, such as 10a<SP>1</SP> ... 10c<SP>1</SP> . . . , the corresponding lever 24a . . . 24c . . . is obstructed against movement by its spring 28 when the projection 26 registers with the recess or flat 16 on its associated cam and when the latching projection 56 is lifted the spring 48 retains the member 42 against the stop 44, or moves it against that stop if it had previously been against the stop 46. The arrangement may be modified for single current transmission, or to transmit positive impulses when the selecting members are in their upper positions 10a . . . 10c . . . .