Patent GB-191512671-A (GB)
Title: Improvements in Impulse Transmitters for Automatic Telephone Systems.
Inventor: BETULANDER GOTTHILF ANSGARIUS
IPC: H04M1/23
Filed: 1915-09-03
Abstract: 12,671. Betulander, G. A. Jan 26. [Convention date]. Impulse-transmitters are set by the operation of a rectilinear movement upon a screwed spindle the threads of which operate the contact springs through a pawl. The receiver is short-circuited during the period of sending the impulses, while the setting movement must be carried to a limiting position before the impulses can be sent. In the arrangement shown in Figs. 3 and 4, a three-threaded spindle 6 is journaled in two disks 4, 5 mounted on rods 1, 2. Secured to the rods 1, 2 is a plate 13 upon which are mounted the transmitter contacts 15, 16, contacts 17, 18 adapted to short-circuit the receiver while the impulses are being sent and a pawl 22 one end of which engages the contact 16 through an insulating-piece 25, while the other end 21 engages the ends of the screwthreads. The spindle 6 is resiliently mounted on a leaf spring 7 and carries at its upper end a spur-wheel 9 gearing with a toothed wheel 11 loosely mounted on a shaft 10 and secured to a spring-drum 12. The spindle 6 is connected at its lower end to a governor shaft 43 through gearing 44, 45 and a one-way clutch comprising the toothed wheel 45 loosely mounted on the lower journal of the spindle 6, and a spring- controlled member 46 adapted to rotate with the shaft by means of a pin 47 and slot 48. The wheel 45 is provided with radial ratchet teeth meshing with teeth on the member 46. The lower end of the spindle 6 is provided with a collar 35, which, when the spindle is depressed against the action of the spring, is forced under a projection 34 at the lower end of a short tube 33 pivotally mounted on pins 51, thereby keeping the spindle 6 in its lowered position. A pawl 39 pivotally mounted in the disk 5 " engages the lower ends of the threads when the spindle is in its lower position, thereby preventing the backward rotation of the spindle before this pawl and the threads are disengaged. The operation of the arrangement is as follows. When the receiver has been removed and the finger or a pin is placed between the threads at a selected point, the pawl 22 prevents the rotation of the spindle 6 until the spindle is lowered out of the path of the pawl 22 and into the path of the pawl 39, in which position the collar 35 is placed under the projection 34. The subsequent downward movement of the finger rotates the spindle against the action of the spring in the drum 12, while the first movement of the wheel 11 causes a projection 34<1> thereon to disengage the lever 27, thereby allowing the contacts 17, 18 to short-circuit the receiver. The members 45, 46 of the one-way clutch pass over each other, while the pawl 39 engaging the lower ends of the threads prevents the backward rotation of the spindle if the finger is withdrawn before it reaches its limiting position. When the finger reaches its limiting position, it strikes a member 37, thereby oscillating the tube 33 to disengage the collar 35 and projection 34 when the spindle 6 is raised by the spring 7, and in its backward movement operates the contacts 15, 16 through the pawl 22, the governor controlling the speed of this movement.