Patent GB-191412913-A (GB)
Title: Improvements in Electric Impulse Producing Mechanisms.
Inventor: KROPP JOHN ALBERT
IPC: H04M1/32
Filed: 1914-05-26
Granted: 1915-04-29
Abstract: 12,913. Kropp, J. A. July 29, 1913, [Convention date]. Impulse-transmitters for automatic exchange systems. The forward movement of the fingerhold 7, Figs. 1 and 4, from its normal position to a point over the required number is without effect, but during its return movement, a spring 14 is tensioned; the impulse-wheel 17 is, however, only released when the finger-hold reaches its normal position. The finger-hold is then locked until the transmission of the impulses is completed. The shaft 6 has fixed to it the finger-hold 7, an arm 8, and a ratchet-wheel 9, which, during the forward movement of the finger-hold, rotates idly under a pawl 12 carried by a spring drum 11 mounted loosely on the spindle 55, one end of the spring 14 being secured to the drum 11, and the other to a hub 15 loosely mounted on the spindle 55 and carrying the impulse-wheel 17 and a wheel 16 geared to a worm-wheel and governor. During the return movement of the finger-hold, the ratchet-wheel 9 tensions the spring 14, but movement of the impulse-wheel is prevented by the engagement of a lug 26 on the worm shaft 22 with a catch 48. This catch 48 and a similar catch 49, which prevents movement of the impulse-wheel 17 during the forward movement of the finger-hold, are attached to springs 40, 41 fixed at one end to the back of the casing and at the other end to sliding bars or rods 39, 34 respectively. The rod 34 and catch 49 are controlled as follows: in the normal position of the parts, a pair of balls 45 mounted in the gear 16 engage corresponding depressions 43 in the drum 11, but during the backward movement of the finger-hold, the drum 11 rotates relatively to the gear 16, thus giving the gear 16 &c. an axial movement as shown in Figs. 6 and 7, whereby the spring 41 moves the rod 34 upwardly so as to move the catch 49 out of the path of the lug 26. The bar 39 and catch 48 operate as follows. The forward end of the bar 39 has a double cam-surface 50, 51, Fig. 2, the cam 51 terminating in a straight stop-surface 52 adapted to engage the arm 8 on the shaft 6, and the arrangement being such that during the forward and return movements of the finger-hold, the bar 39 is forced downwards, Figs. 6 and 7, by its spring 40, but when the finger-hold again reaches normal, the arm 8 engages the cam-surface 51 so as to force back the bar 39 and catch 48, thus freeing the lug 26. The spring 14 then rotates the impulsewheel 17, operating the contact 30, 32 until the balls on the gear 16 engage the recesses in the drum 11, when the spring 41 moves the rod 34 downwards. Figs. 6 and 7, and arrests the wheelwork. During the transmission of the impulses, the finger-hold is locked by the engagement of the bar 8 under a cam-lug 38, Fig. 2, on a thin plate 37, which is connected to the rod 34. The gear 16 has a number of holes 56, Fig. 3, one for each position of the finger-hold 7, and the bracket 35 is formed with a finger 57, Fig. 2, so arranged that, when the gear 16 moves towards the drum 11 as the parts of the sender approach normal, the finger 57 enters one of the slots 56 and prevents further rotation of the gear-wheel.