Patent GB-738539-A (GB)
Title: Improvements in machines for extracting vulcanisation bags from pneumatic tyres
IPC: B29C33/76
Filed: 1953-09-03
Abstract: 738,539. Extracting vulcanizing bags from pneumatic tyre casings. SOC. ANON. DES PNEUMATIQUES DUNLOP, and NEBOUT, N. Sept. 3, 1953 [June 10, 1953], No. 24356/53. Class 87 (2). A machine for extracting vulcanizing bags from pneumatic tyre covers comprises means for separating the walls of the cover, means for gripping the bags, these means having two jaws, means for moving the gripping means along a path part of which lies substantially in the equatorial plane of the bag to be extracted, and means for opening and closing the jaws. As shown, a lever system for extracting the airbag from the tyre comprises, Fig. 1, a lever 1 fixed to a shaft 12 pivotable in bearings p, a lever 2 pivoted at m to 1, and a lever 16 pivoted at 17 to 2. Levers 1, 2 are rocked by pivoted hydraulic cylinders 9, 5, and lever 16 is rocked by hydraulic cylinder 68 pivoted at 66<1> on 2. Jaws 74, 75 for gripping the airbag are actuated by a hydraulic cylinder 58, pivoted at 581 on 16, through a spring-loaded link-and-lever system 61, 81, 87. This lever system moves from the rest position shown in Fig. 1 towards a tyre E containing an airbag X, Fig. 19, in such a manner that the jaws 74, 75 move along the path shown in broken lines in Fig. 19, the jaws rising from the rest position VI to position I to seize the airbag (the tyre beads having been spread apart), then descending to position II, then passing through position III and IV to position V where they release the bag on to an arm 150, Fig. 1. The oil supply to cylinders 9 and 5 is controlled by rotary valves 19 and 18. Valve 19 is turned by a chain 23 running over sprocket wheels 19<1>, 43. Valve 18 is turned in a similar way through chain 21 and wheel 25. The sprocket wheels 43 and 25 may be rotated by one or other of two means. One means is an electric motor 38 which, through chain 35, rotates a shaft 122 carrying a cam 29<1> which rocks a lever 32 and hence, through a spring connection, rocks sprocket wheel 43. The shaft 122 also carries a cam 29 that turns sprocket wheel 25 through lever 27. The motor 38 turns the shaft 122 through one revolution and is then stopped by a cam 121, Fig. 13, on shaft 122 acting through an electrical contactor; another cam 119 operates a valve 161, Fig. 1, that controls oil supply to hydraulic cylinder 58; and a third. cam 120 controls oil supply to hydraulic cylinder 152 that swings arm 150 into position to receive the extracted airbag. Another means for turning the wheels 43, 25 and hence the valves 18, 19 is a pair of levers 46, 47 which are a smaller replica of the levers 1, 2, lever 46 being connected to wheel 43 by link 41 and lever 47 to wheel 25 by linkages 48, 45, 44, 39. These levers 46, 47 may be moved by hand to produce small movements that are magnified by the valves 19, 18 into large movements of the levers 1, 2. If the movement of the levers 1, 2 becomes more rapid than that prescribed by the cams 29', 29, links 40 and 26, connected to levers 1 and 2 and to sprocket wheels 42 and 30 on the shafts 123 and 123' that carry the wheels 43 and 25, reduce the movement of the levers. The means for spreading apart the tyre beads include two sets of jaws 117, 117<1>, Fig. 1. Each set has four jaws. The right-hand set 117<1>, Fig. 1, is mounted on a fixed frame 139, and the left-hand set L17 is mounted on a movable frame 94. The movable frame is mounted on a trolley 116 that rolls along guides 143 and is pushed manually towards the fixed frame to position the jaw ends for engagement inside the beads; this engagement is effected by moving both sets of jaws radially outwards from a centre C, Fig. 9, each set being moved by means of a hydraulic cylinder 108 acting through rod 109, trolley 106, and chain 95 secured at both ends to the trolley and operating rack-and-pinion means 97, 98, 100. When the jaws have been inserted inside the beads, the frame 94 is pushed away from the frame 139, to spread the beads, by means of two hydraulic cylinders 146, 149. These cylinders areoperated, under the control of valves 203, 219, Fig. 16, to open the beads to a distance M only, this distance being determined by the interior and exterior diameters d and D of the tyre that is being de-bagged. When the beads have been opened through a distance M the operation of the cylinders 146, 149 is stopped by the devices shown in Fig. 16. These devices include a feeler 164<11> that rests on the outside of the tyre and a pivot 104 at the end of the rod of cylinder 108'. The feeler 164" is depressed by a hydraulic cylinder 164<1> to a greater or lesser extent, depending on the diameter D of the tyre, and the position of the feeler governs the position of a stop-rod 198 and the instant at which the rod is moved to close valve 203 and hence stop the push imparted by piston rod 147 to frame 94: this governance of the stop-rod by the feeler is effected by linkages 164, 166, 167, 170, 176, 177, 180, 181, 186, 187, 188, 190, 191, 192. The pivot 104 is moved to the left; Fig. 16, to a degree depending on the bead diameter d, and the position of this pivot governs the position of a stop-rod 211 and the instant at which this rod is moved to tilt a lever 214 and thus close valve 219 to stop the push imparted to frame 94 by piston rod 148: this governance is effected by linkages, 172, 206, 167, 170, 176, 177, 179 and 209. When the jaws 74, 75 move to grip the airbag the plane V-V<1>, Fig. 1, between them should coincide with the plane W-W<1> between the beads, and the position of W-W<1> will vary with different tyres. This means that at the moment when the jaws grip, the lever 1 must occupy a different position for different tyres, and for this purpose the movement of the controlling lever 46 is limited by a stop screw 186 which abuts a plate 185 on a lever 184 linked by means 183, 182, 180, 177, 176, 170 to the link 167 the position of which is controlled by the diameter D (and d). When the jaws 74, 75 pull the upper part of the airbag out of the tyre, Fig. 19, the end of lever 16 must stop its descent at position II: but this position varies for different bead diameters d, so position II is correspondingly automatically varied by means comprising an adjustable profiled stop 50 which co-acts with a roller 49 on the end of lever 47: the stop 50 is secured to a vertically slidable rod 51 the position of which is determined by the position of lever 172 (which is determined by the diameter d) through the linkages 205, 207, 57, 56 and 54.