Patent GB-898751-A (GB)
Title: Method and machine for forming on a collapsible drum annular bands from one or more endless threads, more particularly for resisting structures of tyres for motor vehicle wheels
IPC: B29D30/38
Filed: 1958-07-29
Abstract: 898,751. Winding tyre reinforcements. PIRELLIS.p.A. July 29, 1958 [Aug. 5, 1957; May 16, 1958], No. 24447/58. Class 144 (1). In a machine for winding a thread or wire in zig-zag path on the rubber-coated surface of a rotating cylindrical drum 1, the thread-laying guide 2 is moved in a closed 8-shaped path, Fig. 3a, in a plane tangential to the drum surface in order to produce the desired laying line, Fig. 3, the said path being achieved by reciprocating the guide 2 in a direction parallel to the drum axis and at the same time, and possibly at double the speed, in a direction perpendicular thereto. The thread or wire may be rubber coated and stretched before supply to the guide 2, and the pitch of the zig-zag winding path may be such that successive convolutions are contiguous whereby the drum surface is eventually covered with a two-layer band forming a tyre reinforcement. Fig. 2 shows the guide 2 carried at one end of a rod 41 which is reciprocated in a direction parallel to a tangent to the drum surface by a crank-pin 47 rotated about an axis 48 and slidable in a slotted cross-member 45 at the other end of the rod. The rod 41 is slidably mounted in a guide 42 carried by a rod 43 which is reciprocated parallel to the drum axis in fixed guides 44 by a rotary crankpin 51 sliding in a slotted cross-member 49 of the rod 43. Fig. 9 shows an alternative arrangement wherein the guide 2 is carried at the articulated junction of two ends of two co-planar connecting rods 64, 65 normally at right angles to each other and each driven at its other end by a rotating circular crank 67, 68 respectively, the rods being pivoted to crank pins 51, 47 which are adjustably mounted in a diametral slot 69, 70 of the respective crank 67, 68. In an alternative arrangement, the crank 68 may be replaced by a double-lobe cam acting on a roller at the end of rod 65, the rod being constrained by a spring-loaded, normally horizontal pivoted anchor link. In all cases, the cranks and the drum may be driven from a common motor through linked gearing and transmission to provide the desired relative rates of rotation. To ensure that a laying roller 34 carried by the guide 2 is always oriented with its axis perpendicular to the laying line, the guide tube 31 on the lower end of which the roller is transversely mounted is keyed to a lever arm 83 connected, by a rod 82 parallel to the rod 64, to an arm 55<SP>1</SP> of a bell-crank lever, the other arm 55 of which carries a cam follower 54<SP>1</SP> bearing on a suitably shaped cam 53<SP>1</SP> keyed to the crank-pin 51<SP>1</SP> of the crank 67. Rotation of the crank causes the cam to pivot the bell-crank 55, 55<SP>1</SP> and thereby oscillate the lever 83 and guide tube 31 to the desired positions. In an alternative arrangement applied to the construction of Fig. 2, the rod 82 is replaced by a sheathed control cable. Fig. 16 shows the guide tube 31 rotatably received in a bush 66 which articulates the ends of the connecting rods 64, 65, the tube being retractable from the drum surface into the bush 66 against a spring 96 by means of a knob 97 slidably engaging upstanding pins 99 on the bush 66. Rotation of the knob, after such retraction, out of alignment with the pins serves to hold the tube, and thereby the roller 34 out of contact with the drum. To provide for a laying line B, Fig. 19, which diverges a little on each side of the laying line A which is obtained with the mechanism shown in Fig. 9, the connecting rod 64 is formed in two telescopic portions 101 and 64, Figs. 20, 21, the part 101 being pivoted on the crankpin 51 and the part 64, which carries the thread guide 2, being urged by a spring 107 towards the crank-pin so that a roller 106 carried by an end extension 104 of the portion 64 bears against the periphery of a cam 103 keyed to the crank-pin 51. The cam 103 is profiled so that on rotation of the crank disc 67, the effective length of the composite rod 101, 64 is varied to provide the desired laying line B.