Patent GB-597887-A (GB)
Title: Improvements in or relating to doffing apparatus for ring spinning and like frames
IPC: D01H9/10
Filed: 1944-11-30
Abstract: 597,887. Doffing-arrangements for spinning and like machines. BRITISH COTTON INDUSTRY RESEARCH ASSOCIATION, FOSTER, G. A. R., and GREGORY, J. Nov. 30, 1944, No. 23912. [Classes 120 (ii) and 120 (iii)] Ring spinning, doubling and twisting frames are doffed by lifting the bobbins so as to cause a few turns of the yarns on them to unwind over the lower ends of the bobbins on to the spindles, catching or picking up the yarns below the bobbins and gripping and severing the yarns below the bobbins so as to hold the ends leading to the spindles and to release the ends leading to the bobbins. These operations may be succeeded by removing the full bobbins, and fitting empty bobbins on to the spindles so as to trap the yarns on them whilst releasing the gripped ends so that spinning or doubling can be resumed. Before carrying out the initial operation, the yarns leading to the travellers from the delivery, rollers may be immobilised. All the spindles on one side of a ring frame may be doffed simultaneously but the preferred method is to operate on sets of spindles, e.g., twelve by means of apparatus mounted upon a carriage traversed along the ring frame on rails and halted in front of the successive sets of spindles. The carriage is held opposite each successive set of spindles by a latching system which releases it upon completion of a doffing cycle and may clutch-in a motor to traverse the carriage forward to the-next set. Before starting to doff the ring rail is lowered and a few turns of the yarns are wound on to the lower, parts of the bobbins. These "doffing coils" may be wound on the spindles but are preferred on the bobbins. The yarn guides or lappets 8a, Fig. 3, are-then manually, lifted clear of the top of the spindle and, to avoid undue slackening of the yarns, a rod may be provided to give a compensating deflecting action. In order to maintain the yarns passing from the lappets to the travellers in a position clear of the bobbins when-the travellers occupy positions in the front halves of the rings, the yarns and travellers may be immobilised by means of a plate 8b having arcuate serrated portions which are brought to face the spindles 4 above the rings. Each bobbin 1 is preferably provided with a flange 1b at the bottom, a neck 1c at the upper end and a shoulder 25 for engagement by a lifter. The bobbins 1 are first loosened on the spindles 4 and the ends 5a of hooks 5 are brought into position below the bobbins whereupon the bobbins and hooks are raised together for a short distance so that lengths of yarn 3 are drawn from. the bobbins to form helices round the spindles, one helix falling over each hook end 5a. It is necessary for the bends forming the hook ends 5a to be of different direction for either hand of twist. The bobbins 1 are lowered and the hooks 5 swing away from the spindles 4 causing the portions 3b of the loops of yarn extending between the spindles and the hooks to be placed in slots 7c, Fig. 5a, and the portions 3a extending between the bobbins and the hooks to be placed in indentations 7b. If the direction of twist were different the portions 3a would be placed in indentations 7d. The slots 7c and indentations 7b, 7d, are formed in a gripping and severing device, comprising a fixed backplate 7a and, for each bobbin of a set, a movable blade 7g and a cutting plate 7e. The lengths of yarn 3b are severed close to the bobbins and are gripped between the movable blades 7g and the back plates 7a until the full bobbins 1 have been replaced by empty bobbins. The bobbins 1 are loosened from the spindles and raised by forked lifters 24, Fig. 9, on a shaft 24a mounted between end-plates 10 slidable on guide rods 11 which are joined at the top by a crossbar 52 and at the bottom are attached to a shaft 53 by which they may be rocked. The end-plates 10 are lowered from their inoperative position at the top of the guide rods 11 by crank arms 12 to which they are linked by connecting rods 13. During their descent the end-plates are rocked outward so that the lifters 24 avoid the tops of the bobbins, and are then rocked inward for engagement of the bobbin shoulders 25. When loosening the bobbins from their spindles the arms 12 and rods 13 operate at a high mechanical advantage and after the initial raising and temporary lowering, for the yarns to be gripped and severed, the end plates 10, lifters 24 and' bobbins 1 are raised to the top of the guide rods 11 whereupon a tray 51 is tilted to push the bobbins from the lifters and guide them into a box 59. Empty bobbins are supplied from a magazine 60, Figs. 9 and 20, to a projector comprising a double set of V-shaped receivers fixed to bars 61c, 61d. The upper bar 61c is mounted on rods 62, movable vertically by a rack and pinion arrangement so that it may be raised for entry of the bobbins into the projector and lowered to place pegs 63 into the bores of the bobbins. The lower bar 61d is perforated with circular holes, larger in diameter than a bobbin base, each hole being supplied with a rubber tab to prevent the bobbins from falling through. The bobbins are pressed from the projector by a downward movement of the upper bar 61c, operating against the holding action of the rubber tabs, when the projector has been placed vertically .above the spindles. The yarns held by the gripping device are released as the empty bobbins are projected on to the spindles and are trapped between the bobbins and the spindles. The magazine 60 is divided into an even number of compartments spaced at a half the spindles gauge apart, and the bobbins from each compartment are pressed towards the projector by a W-shaped spring 80d, but in the normal position of the magazine are withheld by shutters 81a, 81b having openings 81c spaced one spindle gauge apart. The bobbins are fed by moving the magazine alternately to left or right to bring the compartments opposite the shutter openings. The magazine 60 is placed on a slidable carrier which is given its endways feeding motion by means of a double action face cam M. According to the Provisional Specification, when a whole side or whole frame is doffed at once by mechanism mounted on the frame, the initial loosening of the bobbins may be effected manually by a hand wheel on a shaft bearing a series of cams adapted to bear upwards against the underface of a member carrying the bobbin holders.