Patent GB-973693-A (GB)
Title: Improvements in or relating to tyre building machines
Inventor: RICHARDS FRANCIS ARTHUR
IPC: B29D30/26
Filed: 1960-03-31
Abstract: 973,693. Building pneumatic tyres. DUNLOP RUBBER CO. Ltd. March 23, 1961 [March 31, 1960], No. 11310/60. Heading B7C. [Also in Division G1] In an arrangement for automatically positioning a pocket of rubberized cord-reinforcing material around a tyre-building former symmetrically with respect to the mid-circumferential plane of the former, and including an electrical control system, the former is rotated and the pocket fed axially in to the former until the ends of the pocket are in alignment with a pair of pocket - end locating means disposed symmetrically with respect to said plane, the ends of the pocket being associated with the respective end-locating means, and when said pocket has been correctly positioned, terminating the axial feed of the pocket on to the former, which is, or is not, brought to rest. The pocket 21 is fed on to the former 1 by a pocket stick 16 having a threaded extension 16a driven from a motor 19 through a screw-threaded shaft 17. The detecting and locating means comprise photo-electric cells 11, 13 and 12, 14 mounted in brackets 9a, 9b engaging threaded shafts 4, 5 driven from a motor 7, the brackets 9a, 9b being moved simultaneously inwardly or outwardly according to the direction of rotation of the motor 7. The cells 11, 12 are symmetrically disposed with respect to the central circumferential plane of the former 1, and the distance between the cells 13, 14 is equal to that between the cells 11, 12. Light sources 15a, 15b are provided for the two pairs of cells. Initially, the pocket 21 is fed at a rapid rate on to the former 1 with the cells 12, 14 obscured, and the cells 11, 13 illuminated, as indicated in Fig. 2 (not shown). Subsequently, if the length of the pocket is less than the distance between the cells 13 and 14, the cell 14 becomes illuminated before the cell 13 is obscured, Fig. 3, and the circuit of the motor 7 is controlled to rotate the shafts 4, 5 so that the brackets 9a, 9b move inwardly simultaneously, and at the same time the axial feed rate of the pockets 21 is much reduced. The brackets 9a, 9b move inwardly until the illumination of the cells 13, 14 is substantially equal, and this condition is utilized to arrest the operation of the motor 7. The slow feed of the pocket 21 then continues until, as shown in Fig. 5, the illumination of the cells 11, 12 is substantially equal and this condition is utilized to stop rotation of the former 1. If, as indicated by Fig. 4 (not shown), the distance between the cells 13, 14 is less than the length of the pocket 21, the cell 13 will be still obscured when the cell 14 is illuminated, and this condition is used to control the motor 7 to rotate the shafts 4, 5 so that both the brackets 9a, 9b move outwardly until the cells 13, 14 are equally illuminated whilst the pocket is fed slowly until the condition of the cells 11, 12 as shown in Fig. 5 is reached, when the former 1 is brought to rest. Each pair of photo-cells 11, 13 and 12, 14 on the brackets 9b, 9a may be replaced by a single cell. In a modifled operation of the arrangement the pocket stick is mounted to be movable between positions in which its axis is respectively inclined and parallel to the axis of rotation of the former by means of sprockets on the casing 18 engaging fixed arcuate toothed segments on the frame 3. One of the sprockets is driven by a motor energized when the cells 11, 12 are equally illuminated to rotate the casing 18 to the position in which the stick 16 is parallel to the axis of the former 1 so that further axial feed of the pocket does not take place, although the former continues to rotate.