Patent GB-711490-A (GB)
Title: Improvements relating to printing mechanism for use in association with weighing apparatus
Inventor: PULFORD ERNEST ALFRED
IPC: G01G23/18
Filed: 1951-05-25
Abstract: 711,490. Weighing-apparatus. ASHWORTH, ROSS & CO., Ltd. Aug. 5, 1952 [May 25. 1951], No. 12244/51. Class 143 Relates to weighing machines of the kind in which type bars are set by feelers which co-operate with toothed or stepped discs rotatable with the weight indicator and comprises manually - operated means which grip the discs after a weighment and ensure the previous engagement of an anti-fraud device with the disc of smallest denomination. In the embodiment described, the stepped and toothed, tons, cwts., and quarters type - setting discs 14, 15, 16 respectively, Fig. 2, are mounted on the indicator spindle 13. The corresponding feelers 17, 18, 19 respectively are carried by dependent type-setting arms 26, 27. 28, each gravitationally loaded by weights 29, 30, 31, in a direction to engage the feelers with the discs. The feelers are normally held out of engagement with the discs by manually - operated cams 32, 33, 34, Fig. 3, and'push rods 38, 39, 40, engaging plates 35, 36, 37. mounted on the arms 26, 27, 28. The cams are mounted on a shaft 44 bearing a clutch disc 45 having a hole 46 which can be engaged by a peg 47 on the rotatable and slidable member 48 splined to a sleeve 49 carrying a bevel gear 50. If the member 48 is slid towards disc 45, rotation of gear 50 rotates the cams 32, 33, 34 to enable the feelers 19, 18, 17, to move successively into engagement with the discs 16, 15, 14. Whether the clutch can be engaged is determined by an anti-fraud device. Rotation of the gear 50 is effected by the handwheel 56, Fig. 2, gears 51, 53, 54 and shaft 52, one rotation of which effects a weight-printing operation. When the cams 32, 33, 34 are rotated, the arms 26, 27, 28 are released and set by the feelers 17, 18, 19 and discs 14, 15, 16 to set three slidable type bars, two of which 59, 60 are shown, through push rods 57, 61. The printing then takes place and the feelers are removed again from the discs, ready for the next weighing. The tons type bar 59 is rotatable, bearing several rows of indicia corresponding to the different capacities to which the apparatus may be set. The rotation is effected by a pulley 70 operated through a Bowden cable from a pulley on the capacitychanging handwheel shaft To avoid errors, the type-setting arms 28, 27, 26 are released in succession and feelers 17, 18 are each rotated by an amount depending on the movement of the previous arm. Thus the arm 28 carries a cam surface 77 which operates a lever 79 to control the vertical position of a plunger mounted in a fixed member 81. The feeler 18 on the arm 27 is controlled by a roller 85 restrained by an arcuate cut-away portion of a plate 83 mounted on the plunger. The distance through which the feeler tip 18 is thus lowered depends on the distance moved by the arm 28, and the path it traces out is a horizontal straight line. The cam plate 86 on the arm 27 controls the position of a plate 88 mounted on a second plunger in the member 81 and the feeler 17 on the arm 26 is controlled by an arcuate opening in the plate 88, in a manner similar to that described for feeler 18. The anti-fraud device comprises a T-shaped feeler 91, Figs. 2, 3, mounted on a sliding block 93 above the disc 16 and furnished with a hard rubber strip adapted to be lowered on to the teeth of the disc when block 93 is pushed downwards on the vertical guides 97 by a cable 94. If the scale is not in equilibrium when the feeler 91 is lowered, the feeler is moved sideways along a rod 96 so that a peg 99 is moved out of register with a gap 105 in a plate 103 carried by the clutch-operating arm 100. This prevents movement of the latter to engage the clutch members 45 ... 48, and thus prevents the setting of the type bars. The feeler 91 is returned to its central position, when raised, by a pair of guides engaging the peg 99, but this operation cannot be performed until the hand wheel 56 has received a complete revolution. During the type setting and printing the disc 16 is gripped by jaws held together by a spring 110 when a lever 111 is released by movement of the clutch-operating lever 100. A hand lever 95 is provided to unlock and grip the disc 16, subsequent to the operation of the antifraud device. The lever 95 is mounted on a shaft 121, Figs. 9, 10, upon which is also mounted a lever 122 which is cocked when a catch 125 holds the block 123 against a compression spring. The block 123 carries a peg 124 which in the cocked position engages the block 128 on a lever 127 and raises the latter when lever 95 is raised. A slot in lever 127 engages a peg which operates the Bowden cable 94, Fig. 2, of the anti-fraud device. The lever 127 also engages projections 144, 145, Fig. 11, on plungers 140, 142 which are raised to unlock discs 136, 137 on the shaft 55 of the handwheel 56 and allow its rotation. Plunger 140, in addition, actuates a lever 146, Fig. 2, link 147 and lever 148 which rotates shaft 102 to move the clutch-operating lever 100. An override spring 149 absorbs movement of link 147 when the clutch cannot be engaged. The lever 127 is locked in the raised position, after the handwheel 56 has been unlocked, by a lever 150, Fig. 10, having a peg 152 which engages an inclined slot in the projection 144 on the locking plunger 140, and brings the pawled tip of lever 150 under the lever 127. Lever 122 is locked in the raised position by a projection 154, Fig. 2, on a spring-loaded arm 153. The cam 134, Fig. 11, operates a lever 156, Fig. 2, to operate a push-rod 157, Figs. 2, 9, which uncocks the lever 122, which thereupon loses control over lever 127. The printing operation is performed by cam 135 which depresses the printing hammer 65. A short delay in the rotation of shaft 55 to ensure sufficient time for the correct setting of the tons feeler 17 is produced by a cam 133, set a few degrees ahead of cam 135, and opeating a further spring-loaded plunger. To free the mechanism and accomplish zeroizing, the lever 146 has an extension 162 contacting the locking lever 153. The heavy spring 165 operating through the link 147 returns the clutch-operating lever 100, to remove the disc-gripping jaws, and releases the locking lever 153 to enable lever 122 to fall. The latter is recocked by the cam-plate 159, Fig. 10, engaging the peg 124, while lever 127 is released by the withdrawal of the locking lever 150. so that the anti-fraud device is released and zeroized. Specification 452,170 is referred to.