Patent GB-732352-A (GB)
Title: Improvements in machine for heat treating the tread grooves of pneumatic tyres
IPC: B29C35/00
Filed: 1951-10-31
Abstract: 732,352. Pneumatic tyres. UNITED STATES RUBBER CO. Oct. 31, 1951 [Feb. 2, 1951], No. 25426/51. Class 144 (1). A machine for heattreating the tread grooves of pneumatic tyres comprises a carriage movable from a loading station to a heating station, the tyre being clamped concentrically on the carriage at the loading station in such manner as to squeeze the tyre so that the tread grooves are opened out and the carriage thereafter being moved to position the tyre at the heating station. During the heating operation the tyre is rotated and a protective liquid coating is applied to the tyre tread. Thereafter the carriage is returned and the tyre cooled and unloaded. The machine may have a loading station at each end and a heating station in the middle so that while one tyre is being treated at one end of the carriage an already treated tyre at the other end of the carriage may be removed and a fresh tyre loaded for treatment. The carriage 10 and tyre-clamping means 11, 12 are supported from a pair of overhead tracks 13, lifts 18, 19 being provided at the loading stations A, C respectively for moving a tyre into and out of operative position on the carriage whilst one of its ends is at a loading station and the other end at the heating station B. The carriage is reciprocated by means of a doubleacting power-cylinder C9, the piston-rod 44 of which is connected to a bracket 45 on a trolley 20 from which the carriage 10 is suspended. As seen in Figs. 1 and 2, the tyre-clamping means 12 (identical with that at the other end of the carriage) comprises a rotatable plate 57 dependingly carried by a trolley 50 and movable towards and from a rotatable plate 27 on the carriage 10 by means of a double-acting power cylinder C-6 connected to the trolley 50. The clamping plate 57 carries three pins 79-81, Fig. 7 (not shown), for centralizing the tyre and is adapted to be held to the carriage 10 by a locking head 64, Fig. 6, provided on the rod of a piston and cylinder unit C-7 to engage a shoulder 62 on the piston-rod 59 of a piston a cylinder unit C-8 by which the squeezing of the positioned tyre is effected. Gearing is provided to effect synchronized rotation of the plates 57, 27. With the carriage in the position shown in Fig. 1, the tyre to be operated upon is placed in a V-shaped trough of the lift 18 which is actuated, to bring the tyre into axial alignment with the carriage, by means of a power-cylinder C-1 the lift 19 for operating at the other end of the carriage being similarly actuated. Means are provided to prevent the actuation of the lifts to engage the treated tyre before the clamping means have been moved away from the carriage. The heating device, Fig. 10, positioned at station B, comprises a fixed frame 120 and a frame 121 movable towards and from the frame 120 by means of a power-cylinder C-5 so as to enclose the tyre or allow passage of the carriage suspension 24. Arranged in semi-circular layout within the frames 120, 121 are electrical heating units 130 which are mounted for radial movement towards and from the tyre by means of electric motors M-3, M-4. For properly positioning the heaters relatively to the tyre, one of the units is fitted with a photo-electric switch and a light source on opposite sides of the tyre, the motors M-3, M-4 being automatically cut-out by the interruption of the light-beam at a predetermined radial location of the heating units. Cooling liquid, for preventing scorching of the tread during the heating operation, is applied by means of a flexible rubber &c. roller 159, Fig. 12, freely rotatable, and slidably mounted, in the end walls of a liquid reservoir 163 into which the roller dips. The roller is urged upwardly by springs 164, the reservoir and its devices being counterbalanced by a suspended weight 175 and moved with the heating elements up to the tyre by bevel gearing 174, 138. The effective pressure of the roller on the tyre is controlled by a valve V-15 in a compressed-air circuit 165 connected to the hollow spindle 160 of the roller. For cooling the tyre, jets arranged at the loading stations A, C are supplied from a coldwater conduit through normally-closed solenoidoperated valves. Conduits for the distribution of pressure-fluid to the various power-cylinders are arranged between main supply and exhaust lines, each conduit being fitted with a solenoicloperated reversing valve and a speed-control valve whereby the operational time of each piston is determined. The operation is controlled by limit switches actuated by the movements of the carriage, the associated clamping plates loading lifts, heater frames, heater elements, and tyre-rotation gearing; the electric heating and spray cooling are controlled by timer devices. Specification 699,875 is referred to.