Patent GB-741586-A (GB)
Abstract: 741,586. Calculating-apparatus; transfer mechanism. BURROUGHS CORPORATION. July 23, 1953, No. 20492/53. Class 106 (1). In a calculating machine wherein tens transfer is effected by the displacement of zero abutments to permit an extra step of return movement of the differential actuators, the resetting of displaced zero abutments and corresponding actuators is effected by spring means, which are released and re-energized by the cyclic operating mechanism but, in total-taking, are released immediately upon operation of the total-taking key in order to obviate an initial resetting cycle. The invention is applied to the apparatus described in Specification 741,583, which has differential racks 76 normally arrested in home position, each by engagement with a face 85 of a rocker 82 held by a transfer latch 86. At transfer, the latch is tripped and the rocker moves under spring action to present a second face 84 to the rack, so allowing the rack an additional step of movement. During the next cycle, a rod 107 moves rearwardly to restore released rockers, and a rod 112 restores the racks forwardly to home position. The invention provides spring power means for operating these restoring rods and adapted to exert maximum power towards the end of the restoring movement. In add/subtract operations, the spring power is released and operates with the forward movement of a main operating member OP. In total-taking, the spring power is released by operation of the total key to effect immediate restoration of the racks and rockers before the racks move forwardly under control of the operating member to zeroize the totalizers. The spring power means comprises a power lever 120 pivoted at 121 and connected through an intermediate lever 130 with a set of tensioned springs 128. The lever 130 is pivoted at 132 to a fulcrum arm 133, and a dash-pot 148 controls leftward movement of the power lever 120 when released to the action of the springs. A link 123 and stirrup 103 connect the power lever 120 with a transverse bar 104, a resilient linkage (see Specification 741,583) connecting the bar 104 with the restoring rods 107, 112. Leftward movement of the power lever 120 to actuate the bar and restoring rods is normally prevented by engagement of a nose flange 140 of the lever with a rocker 135, which is pivotally mounted below the transverse bar OP (shown broken-away over its middle part) of the main operating member and restrained against counterclockwise movement under the pressure of the power lever by contact with a blocking plate 141. During the first half cycle of an add/subtract operation, the power lever 120 follows the forward movement (to the left) of the bar OP, the rocker 135 moving round to the front of the nose flange 140 (see broken-line position); the bar 104 moves with the power lever and actuates the restoring rods 107, 112 for the differential racks and their rockers. The lever 120 is returned and the springs 128 retensioned by return of the bar OP, the rocker 135 moving back round the nose flange 140 of the lever, and finally abutting the blocking plate 141 to hold the lever. In the event of the power lever 120 failing to follow the bar OP, a slotted link 200 on the bar is adapted to pick up a pin 201 on the stirrup 103 and so effect actuation of the bar 104. Depression of a total key to initiate a total operation shifts a rod 149 rearwardly, a cam 152 thereon rocking a bell-crank 155 on ear 153 of which engages a notch behind the cam to retain the rod in set position. These movements of the rod and bell-crank result in forward and return movement of a link 172, forward movement due to a pin-and-slot connection 174 with the bell-crank and return movement due to a spring-loaded arm 166 on the rod brought up to a pin 171 on the link. In its forward movement, the link 172 picks up a rod 179 on a lever 187 by means of a notch 176, moving the rod 179 rearwardly and the lever 187 downwardly as it returns. The conscquence is that a rod 189 on the lever 187, which normally maintains the blocking plate 141 in effective position, is moved down clear of the blocking plate. The blocking plate is now free to turn clockwise about a vertical pivot 143 so that the rocker 135 is no longer able to hold the power lever 120. The released power lever consequently moves forwardly under the action of its springs 128 to actuate the restoring rods 107, 112 and before the total cycle is initiated. The usual motor clutch is tripped to initiate the cycle by means of a lever 192 connected with the power lever 120. As the operating bar OP moves forwardly during the cycle, the rocker 135 cams over the nose of the power lever and resumes its normal (broken-line) position in front of the flange 140; the power lever is consequently returned and the springs 128 retensioned as the bar OP returns rearwardly. Initial disengagement of the totalizer is effected by means of a link 162 connecting the bell-crank 155 with a lever 24; this lever is referenced 119 in Specification 741,583 and is adapted to engage and disengage the totalizer in the manner described in that Specification.