Patent GB-148292-A (GB)
Abstract: 148,292. Felt & Tarrant Manufacturing Co., (Assignees of Turck, J. A. V.). May 1, 1918, [Convention date]. Adding-apparatus; zeroizing-mechanism.- Relates to zeroizing-mechanism for calculating apparatus wherein a part of each registering train is adapted to be disengaged from those wheels of the train controlled by stops and other restraining devices to permit the numeral wheels to turn to zero, and consists in utilizing the springs of the transfer mechanisms to effect the backward rotation of the numeral wheels to zero. Toggle-mechanism is provided for holding the parts of the trains in normal engaged position, the release of the toggle being effected by operation of the usual zeroizing handle. The invention is described as applied to key-set and operated-machines of the comptometer class, as set forth in Specifications 13094/04, 26772/12, and 16036/13. The actuating-segment 18 of the machine gears with a pinion 19 on a shaft 21 carrying an internal ratchet 22 and a lantern wheel 25, Fig. 5. A wheel 26, Fig. 3, at the side of the lantern wheel normally gears with a wheel 27 driving the numeral wheel 33 through gear-wheels 29, 30. The wheels 27 and 29 are mounted in a frame 51 pivoted about the axis 30 of the numeral wheel, the frame being swung downwards to break the train of gearing when the zeroizing-handle 62, Fig. 10, is pulled forwards. The transfer mechanism includes a spring 34 attached at one end to the wheel 27 and actuating a double cam 35, Fig. 5, engaged by a roller 39 on a lever 37, which carries a transfer pawl 41 and a detent 42 engaging the pins of the lantern wheel of higher order, The lever 37 also carries a back-stop pawl 45, and is normally held rigid, to prevent overthrow, by the engagement with a tail portion 45<1> of one arm 41<1> of a three-armed dog 44. During transfer and zeroizing the arm 41<1> is moved out of locking position to permit movement of the lever 37. The connexion between the zeroizing-shaft 61, Fig. 10, and the pivoted gear frames 51 comprises a sector arm 63, having a rack and pawl full-stroke arrangement, a cranked lever 66 having a cam edge 65 engaged by a roller 64 on the arm 63, and a link 69 connected to an arm 71 on a rock-shaft 72, the lever 66 and link 69 forming a toggle system. Arms 73 on this rock-shaft 72 are connected to curved levers 74 having slotted shifting pivots on a shaft 75 and pins 76 located within the forked ends of toggle links 82, pivoted on shafts 83 carried by the gear frames 51. The other links 79 of the toggles are mounted on a fixed shaft 81, and the toggles are held in their two positions by springs 84 secured to the gear frames and to a fixed part. Normally, the toggles 79, 82 are in the dead-centre position, as shown in Fig. 3, with the wheels 26, 27 in mesh. Upon pulling forward the zeroizing- handle, the pins 76 push down the forked ends of the links 82 and break the toggle, as shown in Fig. 10, and the wheels 26 and 27 are put out of gear. The wheels 27 are then rotated by the transfer springs until one of two zero stop pins 88 thereon meet a stop-piece 85 set in position by the toggle link 82. The setting of the stop 85 also unlocks the dog arm 41'. On the return stroke of the zeroizing-handle by hand or by a spring 91 the roller 64 on the sector arm 63 moves away from the cam edge 65, and after an interval meets a projection 92 on the lever 66 and reverses the toggles, the parts being restored to normal position by the action of a spring. The roller 64 then occupies the upper part of the cam 65. The movement of the handle in both directions is limited by a stop 100, and is merely sufficient to break the toggles, the final movement of which is effected by the springs. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the following subject-matter :-The operation of zeroizing also unlocks the various devices for preventing misoperation and restores the machine to normal. The lever 66 is connected by a link 115 with an arm 112, Fig. 10, on the rock-bar 105 provided for controlling the latches 108, Fig. 1, used for preventing actuation of the segment levers 17 when a key is only partly depressed, the rockbar thus being set to the release position automatically on zeroizing. The locking-devices 117 and 121, Fig. 3, for preventing depression of a key while it or its segment is making an upstroke, and for preventing movement of the lantern wheels during the down-stroke, are also returned positively to the normal position. This is accomplished by an arm 128, Fig. 10, on a rockshaft 122 having arms 123, 124 engaging the ends of the locking-devices, the arm 128 being moved by a roller 129 on the lever 66. Provision is made for delaying the re-engagement of the gearwheels 26 and 27 until all the keys and segment levers are in the upper normal position. The brake-arms 131, Fig. 1, formerly employed to steady the segments, are utilized for this purpose. They are engaged by a cross-head 138 carried by arms on a rock-shaft 136 connected by a link 141, Fig. 10, with a curved ratchet 142. This ratchet is engaged by a pawl 144 pivoted on the sector arm 63 and prevents return movement of the sector arm until the ratchet is moved away from the pawl on the release of the key. After the return of the zeroizing-handle and under the action of the toggle springs, a cam-part 151 on the lever 66 engages a cam 152 on the ratchet 142 and moves the rock-shaft 136 over to the right to set the cross-rod 138 out of engagement with the brake arms. This subject-matter does not appear in the Specification as accepted.