Patent GB-866011-A (GB)
Title: Improvements in or relating to automatic processing plant
Inventor: HADLEY GEORGE
IPC: B65G49/04
Filed: 1956-09-07
Abstract: 866,011. Conveyers. SILVERCROWN Ltd. July 23, 1957 [Sept. 7, 1956], No. 27532/56. Class 78 (1). [Also in Group XXXVI] An electroplating apparatus comprises a main drive for locating each of a number of articles for equal periods in each of a series of successive treatment stations, i.e. lateral transfer of articles either submerged in an electrolytic bath or between two baths, and lowering and lifting means where appropriate, and at least one auxiliary drive for locating the articles in one of the treatment stations for a time less than one of the periods. The auxilary drive is called "(the sub-lift mechanism," and is a modified lowering and lifting means. All the lowering and lifting means do one complete down and up movement between each lateral transfer movement. The plant comprises treatment stations S1 ... S32 arranged in baths B1 ... B14, of which B9 is the electroplating bath, and at the loading and unloading points S1, S31, S32. The four lifting and lowering mechanisms are positioned adjacent stations S1-S2, S6- S8, S11-S15 and S25-S30, the last mechanism including the sub-lift structure for ensuring a reduced time of immersion in the passivating bath B12. Articles to be plated are supported on jigs 65, Fig. 6, carried by cages 58 which have rollers 61 adapted to run up and down pairs of tubes 51 which extend between a pair of endless chains 46, 47 which encircle the plant, the chains engaging respectively sprockets 44, 45 on shafts 40 which are mounted at each corner of the plant. One of the shafts 40 is adapted periodically to be rotated by an electric motor and thus move the jigs 65 around the plant in stages, the chain 46 having rollers 50 which engage a track 37. Conductor plates 213 on the cages 58 rest on a copper bus-bar, which runs round the plant, when the jigs 65 are in their lowered positions, the bus-bar being suitably interrupted and electrically connected. The four lifting and lowering mechanisms are similar to that near stations S6-S8, Fig. 8, which comprises two cages 90 having grooved rollers 95 which run on the flanges 12b of vertical H-beams 12 (see also Fig. 1), which support the parts of the plant. Secured to the cages 90 is a lift beam 101 which supports a box-like assembly, including a top plate 103, in which slides an extendable toe 107, Fig. 12, having an upstanding lug 114 engageable by an arm 68 on the cages 58, Fig. 6. During lateral transfer of a jig 65 between baths a roller 67 on the jig runs along the plate 103 and along a plate 113 on the toe 107, which is withdrawn from the box-like assembly by the engagement of the arm 68 with the lug 114. The toe is retracted during lowering after the plate 213 has engaged the bus-bar, and has thus arrested descent of the cage 58 by a resiliently mounted bar 140, Fig. 12, which contacts a roller 117 on the toe 107 thereby ensuring that raising of the beam 101 will not lift the cage 58 at stations S8, S16, S31. The plant, which is automatically controlled by electric circuits operated by limit switches engaged by the jigs 65, operate as follows, assuming all cages 58 are resting on the bus-bar and a new jig 65 is loaded at S1 : A motor 70, Fig. 1, is energized to drive the four -lifting mechanisms through suitable shafts, as e.g. 73, 83 for that near S6-S8, which drive endless vertical chains to which the cages 90 are secured, which thereby lift the beams 101 which contact the rollers 67 on the cages 58 which are hence raised at the stations S1, S6, S7, S10 to S15, and S25 to S30 i.e. the localities at which are the lifting mechanisms. Limit switches de-energize the motor 70, and after a delay of two seconds, the motor for the chains 46, 47 is actuated to cause transfer of all cages 58, including those still submerged, by one station after which a cam-operated limit switch de-energizes the motor. At this stage, cages 58 now at S2, S8, S16, S31, i.e. those which will not require lifting prior to the next lateral transfer, have withdrawn the toes 107, which are subsequently retracted, as described, on lowering of the beams 101 by energization of the motor 70. (The lift beam adjacent S1, S2 has no toe 107, being itself laterally movable by the roller 67. The beam is returned by a construction similar to that described with reference to Fig. 12.) The lift beams, except that at S1, S2, have hinged heel members 126, Fig. 8, which are knocked upwards about the axis H-H, Fig. 8, by the rollers 67 at S6, S10, S25 as the cages 58, at rest on the bus-bar, are passed by the continuing downward movement of the lift beams, which are arrested below the cages 58. The heels 126 are thus in position to contact the rollers 67 on next being raised. Sub-lift mechanism.-The lift beam 207, Fig. 16, of the lift mechanism at S25 to S30 has a cut-out portion 205 adapted to accommodate a sub-lift beam 202 carried by an independently driven sub-lift cage 196 which runs by grooved rollers 199 on tubes 195. The recess 205 is positioned opposite the passivating bath B12. The motor for the cage 196, which is moved through the intermediary of an endless chain and a driving cage similar to the cage 90, is operated simultaneously with the motor 70 to lift jigs 65 out of baths B9 ... B14 but is operated to lower its jig 65 into the bath B14 a predetermined time, e.g. 25 seconds, after lowering of the beam 207 to ensure a reduced time of immersion in the bath B14. The sub-lift beam 202 may be arranged to act on more than one cage 58, simultaneously, and may be arranged to be lowered simultaneously with the main beam and raised prior to the raising of the main beam.