Patent GB-520430-A (GB)
Abstract: 520,430. Typewriters. NATIONAL CASH REGISTER CO. Oct. 13, 1938, No. 29662. Convention date, Oct. 13, 1937. [Class 100 (iv)] [Also in Groups XIX, XXIV and XXIX] In a calculating and similar accounting machine with a travelling carriage power means are provided for moving the carriage in both working and return directions, the motion transmitting connections being under the control of means operable by the power means. In a preferred form a fluid coupling is provided between the power means and the controllable connections and the power means is separate from the power means utilised to drive the main operating mechanism of the machine. The invention is shown applied to a machine of the Ellis type described in Specifications 28,253/08, [Class 100], 445,281, [Group XIX], and 461,347. Carriage -driving mechanism.-The calculating mechanism is driven by motor 36, Fig. 8, whereas the carriage-driving mechanism is driven by a separate continuously running motor 119 connected through gearing 122 to a shaft 125. The shaft 125 drives pinions 126, 127 driving a hydraulic clutch 135 described below the clutch forming a non-positive driving means for a shaft- 145 connected by gears 147, Fig. 10 to a  driving shaft 110. 'Two bevel wheels 109, 115 are freely mounted on the driving shaft 110 and either one or the other is connected thereto by a pair of sliding dog clutches 113, 117. A bevel wheel 108 meshes with the bevel wheels 109, 115 and is secured to a shaft carrying a pinion 103 engaging a rack 102 secured to the carriage 96 so that the carriage is moved or tends to move, in one direction or the other depending on which dog clutch is engaged. The carriage is controlled in its right-to-left movement by escapement and tabulating mechanism referred to below. The dog clutches 113, 117 are changed over, whenever the carriage reaches either end of its travel by power operated carriage-controlled mechanism. When the carriage reaches its extreme left-hand position a cam 198 on the carriage pushes rearwardly a bar 195 to rock a lever 193 about its pivot 194 Fig. 11 the lever engaging a pin 189 to rock a latch 186 which releases a yoke 173 for clockwise movement under the action of a spring 185. The yoke moves a clutch member 176 splined to a shaft 165 into engagement with clutch teeth 179 secured to a helical cam 164. The shaft 165 is continuously driven from the carriage-driving motor 119 through the shaft 125 and gears 181. The helical cam 164 rotates through 180 degrees and by engaging a pin 163 on a slide 156 carrying pins 153, 154 operating the dog clutches moves the slide to the left to disengage the clutch 117 and engage the clutch 113. The drive to the carriage is thus reversed and the carriage is returned to the right. When the helical cam 164 has rotated through 180 degrees a cam projection 170, Fig. 14, upon, it engages a pin 171 on the yoke 173 and returns this yoke anticlockwise to break the drive to the helical cam, the yoke being latched by the latch 186. When the yoke was moving clockwise to engage the drive, an ear 199, Fig. 11, upon the yoke rocks an arm 190 carrying the pin 189 whereby a slot in the latch 186 allows this latch to return immediately to latching position. When the carriage reaches its initial right hand position another cam 199 upon it engages the bar 195 the helical cam 164 then being given another rotation of 180 degrees and the dog clutches 113, 117 again being changed over to drive, or tend to drive the carriage to the left again. Tabulating mechanism; escapement mechanism. -Mechanism similar to that described in Specification 514,973 is provided for :-(a) letterspacing upon operation of a typewriting key; .(b) releasing the carriage (by depressing a finger lever) for movement to the left until stopped by typewriter tabulator stops mounted on the carriage; (c) automatic column-spacing, the carriage being released for this by the calculating mechanism the resulting tabulating movement being terminated by co1umn spacing stops on the carriage; (d) releasing the carriage for a column-spacing movement by depressing a key, the movement being terminated by the column spacing stops. Hydraulic clutch.-The driving shaft 128, Fig. 4, drives the plate 129, casing 135 and plates 136, 137, 138. The casing 135 is shaped as shown in Fig. 9 and contains pinions 141, 142 freely pivoted to the plate 129 and gearing with a pinion 140 secured'to the output shaft 145. The two chambers of the casing are connected by passages. The effective area of these passages is varied by screws 149, 150 which can thus be set to control the torque transmitted. The plate 136 forms an oil reservoir. A conical member 152 secured to the driven shaft minimises oil seepage. An oil seal 146 is also provided. Specification 497,640, [Group XIX], also is referred to.