Patent GB-819283-A (GB)
Abstract: 819,283. Calculating-apparatus; transfer mechanism. UNDERWOOD CORPORATION. Dec. 20, 1956 [Dec. 29, 1955], No. 38803/56. Class 106 (1). [Also in Group XVI] A calculating-machine has differential mechanism comprising a setof actuators each associated with a driving member, which as the driving members are moved together through a predetermined distance, drives the actuator against a selectively set stop corresponding to the digit to be entered in that order, causes an aligning or justifying element to engage the actuator and retain it in its set position and then re-sets the stop. As described, the stops are pins of a pin-carriage set by means of a ten-key mechanism. By means of the invention, the carriage may be restored relatively early in the cycle and need not be restored beyond its initial position. Moreover, the operator may commence setting of the next item prior to the end of the operation. Driving mechanism.-Depression of any control key rocks a machine-release shaft 79, Fig. 3, which acts through a link, Fig. 27 (not shown), to trip a one-revolution clutch, driven by an electric motor, having an anti-rebound arresting device, and driving a main-shaft comprising three coaxial sections 41, 42, 43, Figs. 3, 4 and 5, which always rotate as a unit by virtue of interconnected crank pins. Setting pin-carriage.-Depression of a key 100, Figs. 1 and 29, rocks a corresponding lever 106 to push a bar 108 rearwardly. A lever 118 on the bar engages a pin-setting slide 122 and moves it rearwardly, but is also rocked by engagement with a stop 121, so that on full depression of the key, it disengages the slide 122 and allows the latter to be restored by a spring. Thus another key may be depressed prior to the restoration of the first. The bars 108 are connected individually by springs 110 to a plate 112 adjustable by a thumbscrew on the keyboard to vary the key pressure required. The slides 122 for the " 0 " to " 8 " keys co-operate with a bail rod 125 embraced by the slide 122 for the " 9 " key which is thus actuated on depression of any amount key. On depression of the " 9 " key, the corresponding lever 118 acts directly on the bail carrying the rod 125. The slides 122 actuate the pins 148 of a pin-carriage 134 (see also Fig. 7) laterally movable on rollers which engage a rod 138. An escapement pawl 153 co-operates with the " 9 " pins 148 so that when any amount key is depressed and the " 9 " pin for the order being set is actuated, the carriage is advanced one step by a spring 152. The support rod 138 and escapement pawl 153 are mounted within a frame 140, itself laterally movable, to a small extent. Back-spacing pin-carriage.-Depression of a back-space key, through a link 162, Fig. 7, rocks a lever 164 and a pawl 166 carried thereby engages a rack 169 fast with the pin-carriage to return the latter by one step. The lever 164 then rocks a plate, Fig. 7A (not shown), which restores the actuated pin or pins 148 in the column last set. Differential mechanism.-The differential actuators 177, Fig. 1, are guided for vertical movement by a bar 178 and a comb 180. They are driven by means of a vertically movable frame 181 reciprocated by mainshaft cams during each cycle and carrying on a rod 185 a drive lever 186 for each actuator. Initially, a roller 192 on each lever 186 is positioned in a slot of the actuator and consequently, when the frame 181 is raised, the actuators 177 are moved upwardly. However, when the foot of an actuator engages a projected pin 148 of the pin carriage, its drive lever 186 is cammed clockwise, as shown in Fig. 33, and a pawl 188 carried thereby rocks an associated aligner or locking lever 193 about its fixed pivot 194 so that a stud 196 engages teeth of the actuator to prevent further upward movement. A forward extension of the lever 186 then restores the set pin 148 as the lever 186 continues its upward movement with its roller 192 running along the front of the actuator. During the return movement, the rollers 192 re-engage the notches in the actuators and so disengage the aligner levers 193 and then restore the actuators. A plate 205 mounted to move laterally with the pin carriage arrests in zero position any actuators for the higher orders in which no digit is to be entered. It is moved rearwardly to effective position at the beginning of a machine cycle by a cam-operated link 212, which acts on a plate 206 coupled to the plate 205. The plate 206 is moved into the path of the link 212 when the pin-carriage makes its first step on depression of an amount key. A detent 208 holds the plates 205, 206 effective until after they have arrested the actuators, when they are restored by the drive levers 186. Restoration of pin-carriage.-During the second half of a machine cycle while the actuators are being restored, a cam-operated linkage acts on a roller 146, Fig. 7, secured in the pincarriage to restore the latter to its initial position in which it is held by the engagement of the escapement pawl 153 behind the highest order " 9 " pin 148. Locking keys.-A plate 232, Figs. 3 and 5, is allowed to move forwardly early in a machine cycle into co-operation with lugs on the lower ends of the amount keys and control keys (except the Repeat key). Depression of an amount key is thus prevented and also the depressed control key is held depressed. The locking plate 232 is restored prior to the end of the cycle and amount keys may then be depressed for the next operation. Repeat mechanism.-Depression of the Repeat key 242, Fig. 39, rocks a lever 246 to release a spring-loaded slide 249 which actuates the machine release mechanism and also cams the lever 246 further counter-clockwise. A wire 256 pivoted by the lever 246 rocks a member 257 carried by a lever 260 into an operative position in which, when the lever 260 is rooked by a cam, its end will engage a stud 262 in the frame 140, Figs. 3 and 7, supporting the pin-carriage. Thus, in a cycle initiated by the Repeat Key, the frame 140 with the pin-carriage is moved laterally a small amount so that, whilst the pins 148, Fig. 33, still arrest the actuators 177, they are no longer restored by the drive levers 186. When the frame 140 is moved laterally, it also disengages the linkage which normally restores the pin-carriage to its initial position from its cam-operated driving lever. A wire 274, Fig. 3, operated by the machine release shaft 79, engages between teeth of the rack 169, Fig. 7, during machine cycles to prevent oscillation of the pin-carriage. To permit repeated operation at a higher speed when the Repeat Key is held depressed, a cam-operated restoring link 93 for the machine release shaft 79 is depressed by the Repeat Key 242 to an ineffective position. If the Repeat Key is released early in a cycle, the machine will stop at the end of that cycle but with the amount still set in the pin-carriage. If the key is held depressed until after the midpoint of the cycle, a further cycle will follow. An extension 516 of the Repeat Key is blocked by a lever 457, Figs. 5 and 39, controlled by the pincarriage if the latter has not been moved from its initial position by the setting of an amount. Hammer impression mechanism.-A type bar 280, Fig. 1, is pivoted at 282 to each actuator 177 and when the actuators have assumed their differential positions, hammers 289 are released to drive the type bars against a platen 288 to take impressions from the selected type. The hammers are guided in a comb 285 and are normally held in a withdrawn loaded position by a bail 294, 296 (see also Fig. 3) and by latches 298. As the actuator drive frame 181 moves upwardly, rollers 182 therein allow the bail rod 294 to move away from the hammers. As the actuators 177 reach the " 1 " position, studs 306 therein allow shoulders on arms 304 to engage behind ears on the latches 298. The arms 304 are pivoted on a rod 302 carried by levers 301 and when the frame 181 reaches its uppermost position, it rocks the levers 301 and the arms 304 withdraw the latches 298 in all orders in which a significant digit has been entered so as to release the hammers 289. The latter have overlapping ears so that zeros are printed where necessary to the right of the highest significant digit. Line-spacing.-A slide 313, Fig. 3, actuated by the hammer-restoring bail 294 operates a linespacing pawl 322 for the platen. Ink-ribbon.-A bi-colour ribbon passes between spools 329, Figs. 3 and 4, mounted on arms 202 and round angle guides 332 connected to those arms which are oscillated by a cam during each cycle so as to lift the ribbon into position between the platen and the type bars. Feed pawls 346, associated respectively with the pools, are carried by levers 338 interconnected by a horizontal lever 341 so that only one is in a rearward effective position at a time. The corresponding spool is advanced by its pawl as it is lifted and is held against reverse movement by a detent 352. The detent 352 on the other side is held ineffective by a pin 354 in the associated leyer 338. When the feed spool becomes exhausted, a sensing arm 356 moves over an ear 360 of the associated lever 338 when the arms 202 are raised and then, on restoration of these arms, rocks the levers 338 so as to reverse the drive. Correction cycle.-Depression of a Correction key 361, Fig. 3, rocks a lever 364 which releases a slide 366 to rock the machine release shaft 79, and actuates a link 373 to cause a bail 370, Fig. 1, to be urged against the rear of the actuators 177. In the ensuing cycle, the bail 370 engages notches in the actuators to arrest them in zero positions so as to prevent the entry of the amount set and the release of the printing hammers, the drive levers 186 restore the set pins 148, and the pin-carriage is restored to its initial position. The line-spacing mechanism is blocked by a lever 380. Addition and subtraction.- Rearward extensions of the actuators 177, Fig. 1, eac