| 摘要 |
1513773 Weighing mail PITNEY-BOWES Inc 5 June 1975 [5 June 1974] 24241/75 Headings G1A and G1W A scale for weighing a piece of mail comprises a weighing tray 33 for supporting a piece of mail on edge, the tray having a base section 35 and a wall member 34 extending therefrom, means for supporting the tray for movement through a weighing range, and means for measuring the movement of the tray. The tray is supported by a pair of leaf springs 44, 45. The movement of the tray is measured by a photo-electric system comprising a light source 53, a shutter 51 mounted on the tray, a window 52, a prism 56 and an array of photodiodes 57, the photodiodes in the array being successively darkened as the tray descends. The photodiode array may be pivotally adjusted about its bottom end to vary the vertical spacing of the photodiodes so that the sensitivity of the photo-electric system matches the particular leaf springs used (Fig. 3). A spiral spring 65 connected to the tray has its tension automatically adjusted by a motor 63 and a screw and nut arrangement 64, acting under the control of the first photodiode, to zeroise the scale. On the input side of the scale are a pair of input drive rollers 32, and on the output side of the scale are a pair of output drive rollers 58, and a set of arrestment fingers 37. The rollers 58 are mounted on levers 74 for movement between inner and outer positions by means of an eccentric cam 20 acting on a wheel 202 carried by a pivoted arm 204 which engages a pullpush rod 208 linked to cranks 223. The arrestment fingers 37 are rotatable from the closed position shown to an open position under the action of a solenoid 241 which moves member 242 to the left, member 241 having slots engaging drive pins 251 of the shafts 43 of the fingers 37. In use, a letter propelled forwards by input rollers 32 is arrested and held by fingers 37, thus breaking the light transmission path from source 61 to detector 59. This breaking of the path causes solenoid 241 to be actuated to release the letter to fall on to the tray 33, and causes the commencement of the rotation of cam 200 to move rollers 58 towards their inner position, the letter being ejected when engaged by rollers 58. When the light path to detector 59 is restored, the fingers are moved to their closed position and rollers 58 towards their outer positions and another letter is propelled forwards by rollers 32. A further photo-electric detector (81, 82), Figs. 4-7, (not shown), is provided to detect the presence of a letter at the input rollers 32.
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