Patent GB-196527-A (GB)
Title: Improvements in weighing mechanism
IPC: G01G1/38
Filed: 1922-07-26
Abstract: 196,527. Merrick, H. L. July 26, 1922. Relates to weighing apparatus of the kind having an automatically adjusted counterpoise and comprising improved means for adjusting the counterpoise, means for restraining and damping the vibrations of the beam and apparatus for giving a printed record of the weighings. Sliding-weight apparatus.- The counterpoise is adjusted by frictionally contacting travelling elements one of which is movable with the counterpoise, and rotated by a motor, the direction cf travel of the other element being changed in angular relation to the former element to impart longitudinal movement thereto. In the no-load position the counterpoise 22 is in position on the scalebeam 17 adjacent to the pivotal support 18' and the disc 26 is in position to rotate on an axis parallel with the axis of the drum 25, which is rotated by the motor M, and thus the drum is held against axial movement. When a load is placed on the platform 15 the end of the scale-beam is deflected through the connection by the rod 16, and the disc 26 is thereby adjusted to a position 26<a>, Fig. 11, in angular relation to the axis of the drum by means of a pair of fingers 53 adjustably mcunted in a slot of a bracket 54 sus. pended from the scale beam. In this position the disc exerts an axial pushing force on the drum, which therefore moves on carriage-members 27, 28 along the rails 30, 31, thus moving the counterpoise, to which the drum is connected by the arm 34 and the rod 33, towards the higher end cf the beam. As the counterpoise approaches the position of equilibrium the movement of the counterpoise is gradually retarded in accordance with the angular position of the disc relative to the drum. When the load is removed the counterpoise is moved in the opposite direction in a similar manner. To prevent the drum-carriage from over-riding the length of the scale-beam a stop 58 is provided, which comprises an arm carried by a rock-shaft 59 and adapted to engage the drum carriage 27. This engagement rocks the shaft 59 and thereby moves a rod 60 to engage an actuator-arm 61 on the disc-support 44, thus adjusting the disc 26 to the position with its axis in alignment with the axis of the drum. According to a modification of the invention the drum is arranged concentrically with and is driven by a shaft, along which it moves. The shaft is square and the drum carries two rollers at both ends to engage opposite sides of the shaft, and the rollers at one end are at an angle to those at the other. Pendulum-weights are provided supported independently of the beam with which the beam is adapted to co-operate as it is deflected beyond a predetermined point. The levers 158, 159, Fig. 22, have arms 163, 164 carrying adjustable weights 165, 166. The levers are also arranged with auxiliary weights adjustably mounted on arms 167, 168 substantially at right angles to the arms 163, 164 to regulate the pendulum weights. A rod 169 pivotally connected to and suspended from the long end of the beam is arranged with a 'bifurcation having one leg 170 with a hook to engage a pin 172 on the lever 158, and a larger leg 171 upwardly hooked to engage a pin 173 on the lever 159. The reverse movement of the levers is limited by the stops 174, 176, 177, 179. In a modification of the means for restricting the deflecting movement of the beam auxiliary pendulum-weight mechanism is mounted on the levers to act between them and the bifurcated rod 169. To steady the beam as the counterpoise approaches the point of balance, a dash-pot is connected to the long end of the beam. The dash-pot comprises a liquid-carrying cylinder 195, Fig. 20, with an annular central restricted portion 199 and a piston 196 with an annular enlargement 201 of substantially the same diameter as the restricted cylinder portion, so that when the load is first applied or removed or the counterpoise is approaching the point of equilibrium, the movement of the beam is slow. The cylinder also has restricted portions 205, 206 at opposite sides of the central restricted portion to restrict extreme movements of the beam. Recesses 200 are arranged in the cylinder wall at opposite sides of the central restricted portion, and the piston has recesses 202 in its wall at opposite sides of the enlargement to serve as bypasses. Printed records, apparatus for giving.-The bar 66, Fig. 7, is fixed at each end to the carriagemembers, which carry the rotatable drum, and has raised digits and graduations corresponding with the graduations on the weigh-beam, but reading in the reverse direction. The printed record is made on a strip 69 fed transversely to the beam by the rollers 71 and 72, an ink-ribbon being interposed between the bar and the paperstrip. An impression is made on the paper-strip by impinging it against the bar by means of the platen 87, which is actuated by the magnet 90. To make consecutive printed record numbers of the successive weighings a numbering device N is provided to impinge the ink-ribbon and recordstrip against a fixed platen 105 and is operated electromagnetically. The record-strip, Fig. 8, has a series of longitudinal parallel lines of width equivalent to the space between adjacent digits in the bar, so that the space between successive lines represents a predetermined weight smaller than the interval between the graduations on the bar. To indicate whether the scale-beam was in equilibrium at the time the record was made, means are provided to print a dot in relation to a heavy line on the record-strip. The impression device 95', Fig. 10, is carried by a member 96 connected through bell-crank lever 97, link 98, Fig. 7, arm 99, arm 101 and link 102 to the discsupport 44, so that the dot is printed on the heavy line when the disc 26 is vertical. To indicate the total weight of successive weighings a counter 120, Fig. 2, is provided. The bar 66 has rack-teeth 122, which rotate, through intermediate gear-wheels, the gear-wheel 125 being loose on the shaft of the number-wheels of the counter and carrying a spring-influenced pawl 126 so arranged that the numbering wheels are rotated as the counterpoise is moved to its ir.itial position after the removal of each load.