Patent GB-1000776-A (GB)
Title: Electrically powered keyboard and transfer mechanism for ten key adding or calculating machine
IPC: G06C7/08
Filed: 1963-06-10
Abstract: 1,000,776. Mechanical calculating apparatus. R. M. STARRETT. June 10, 1963, No. 23087/63. Heading G4B. A ten-key machine has a set of toothed transfer wheels which are held in turn in engagement with a toothed setting wheel while the latter is adjusted by a powerdriven member moved differentially under the control of the number keys. As described, actuation of any one of the keys 6 depresses a bail 74 to lower a link 81 which in turn depresses a link 30 carrying a depending arm 28. The arm engages a stop 26 on a bell-crank 25, 42 to trip a pawl 21 into engagement with a ratchet wheel 23. The pawl and an arm 38 are mounted on a member 19, idling on a shaft 12 from which the wheel 23 is continuously driven, so as to form a " snatch roll " assembly. The portion 42 of the bell crank carries one end of a spring 46 and co-operates with a portion 40 of arm 38 pivoted to the member 19 and 39 and carrying the other end of the spring, to sweep the spring over the pivot and so lock the pawl 21 by this " overcentre " action. As a result of this action the member 19 commences to rotate anti-clockwise with the wheel 23 against the action of a spring 19a and driving through the action of a link 49 and a spring 57 a differential member 51. When a projection 82 contacts an abutment on the depressed digit key or a projection 83 contacts the stem of the zero key 6a, further motion of the member 51 is prevented but the member 19 continues to rotate expanding spring 57 until a pin 48 on the link 49 contacts a portion 43 of the member 19 tripping it back to the position shown and thus releasing the pawl 21, causing the member 19 together with the member 51 to return under the action of the spring 19a. Reciprocation of the link 51 oscillates through a toothed sector 60 a ratchet wheel 62 through the number of teeth corresponding to the numeral key depressed, clockwise movements of the wheel 62 being transferred through the ratchet connection to a toothed setting-wheel 72. An arm 96 attached to the lower end of the member, reciprocates through an elastic connection 96a an arm 92 carrying a pawl 93 so as to index a wheel 89. The wheel 89 steps a carriage 85 bearing a row of transfer wheels 100 and a row of indicator wheels 106 through a distance equal to the distance between a pair of wheels 100 so as to engage successive wheels 100 with the wheel 72 so that they are set with successive settings of the wheel 72. Locking bars 109, 115 are provided to lock the wheels 100 before and after setting. When the wheels 100 have been set the carriage 85 is released by an enter key and allowed to move to the left, as shown in Fig. 1, to disengage the wheels 100 from the wheel 72 and to engage them with a set of actuator wheels 170. It also releases corresponding release pawls 175 and engages a clutch causing a bail 171 on an arm 168a to move around a slot 172 so as to allow those wheels 170 which have been engaged with the wheels 100 to rotate under the action of springs 173 to zero the wheels 100 (stops 101 on the wheels engaging a fixed stop 102) and pass their information to a printer 219 and either add or subtract wheels 217, 216 in known manner. A row of zero keys is provided so that a string of zeros may be entered by depression of a single key. These operate a second snatch roll and differential member similar to the one constituted by the members 19, 21 and 51 &c. to reciprocate an arm 201 so that a pawl 93a on it indexes the wheel 89 through a desired number of steps to pass a corresponding number of the wheels 100 past the setting wheel 72 so that they are effectively set at zero.