Patent GB-1486608-A (GB)
Title: Ring forming machine
IPC: B29C69/00
Filed: 1974-10-30
Abstract: 1486608 Seaming non-metallic sheet material SPHEREX Inc 30 Oct 1974 46980/74 Heading B5K Apparatus for producing an annular article from an elongate workpiece having a longitudinal groove therein and formed of thermoplastics material comprises first and second clamps 10, 11 attached to a base 34 and adapted to grasp the ends of the workpiece, each clamp 10, 11 including a protuberance of a shape corresponding to and positioned to engage the groove in the workpiece, a heating plate 16 movably mounted on the base 34 and having first and second opposed parallel surfaces, means for presenting the two workpiece ends one to each surface of the plate 16, with bending of the workpiece into annular form, means for causing at least one of the clamps 10, 11 away from the plate after heating, and means for causing the clamps 10, 11 to bring the heated workpiece ends together to effect joining thereof to produce an annular article. Preferably, the annular article is a solid baby carriage tyre 25, Fig. 19, of extruded thermoplastics material having circumferential lands and grooves 26 on the outer surface and an annular V-shape groove 27 on the inner surface. As shown in Fig. 2, clamps 10, 11 mounted on pivots 12, 13 grip a portion of an extruded cylinder 14 with the clamp 10 holding the cylinder 14 tightly and the clamp 11 holding the cylinder 14 in a sliding grasp. The clamp 10 moves a predetermined distance to the left and draws with it the cylinder 14. A cutting blade 15 descends to sever the cylinder and form a workpiece (17), Fig. 3 (not shown). The blade 15 is retracted and the clamps 10, 11 begin turning inwardly on the pivots 12, 13, Fig. 4 (not shown). When the clamps 10, 11 have turned through 180 degrees,Fig. 5, the clamp 10 moves to the right and a hot plate 16 descends so that the ends of the workpiece contact the plate 16, Fig. 6 (not shown), to effect heating. The clamp 10 is retracted slightly to the left, Fig. 7 (not shown), the plate 16 is removed and the clamps 10, 11 force the workpiece ends together to effect sealing, Fig. 8 (not shown). The workpiece is released and the system is returned to its initial position. A ring forming machine 18, Fig. 1, comprises an extruder 19, an acceptor section 20, a take-up section 21, a pre-feed section 22, a processing section 23 and a control system 38. The section 20 comprises wheels 28, 29, Figs. 10 and 12, of which the wheel 28 is an idler rotatably mounted on an arm 33 attached to the base 34 and the wheel 36 is rotatably mounted in the base 34 and driven by a motor 37. A guide 30 is attached to the arm 33 and defines a path 31 for the cylinder 14. The section 21 comprises two arms 39 and a photocell 40, Fig. 1. The section 22 comprises wheels 40, 41, Figs. 10 and 11, of which the wheel 41 is an idler rotatably mounted on an arm 46 on the base 34 and the wheel 42 is rotatably mounted on the base 34 and is rotatable back-and-forth through about 45 degrees by a cylinder 44 acting on an arm 47. A guide 43 is mounted on the arm 46. The section 23, Fig. 10, comprises the clamps 10, 11 and the cutting blade 15 and the hot plate 16 drivable by pneumatic cylinders 48, 49. The blade 15, Fig. 13, the cylinder 48, a blade track 51 and a cutting bed 52 are carried by an arm 50 which also carries the clamp 11 having a stationary jaw 53 and a moving jaw 54 closable by a cylinder 55. The clamp 11 is rotatable by a cylinder 56 through a rack 57 and a pinion 58, the rotation being about the axis of the pinion 58. The jaw 54 is provided with a wedge 54a to engage the groove 27, Fig. 19, on the cylinder 14. The arm 50 also carries cylinders 59, 60, Fig.s 10 and 11, the plate 16 and the cylinder 49. A connector 61, Fig. 10, connects the plate 16 and the cylinder 49 and carries on its periphery a heat insulator 62 and a resilient bumper 63 which biases the plate 16 away from the arm 50 and the clamp 11. Tracks 64, 65, Fig. 11, are provided and along which the base 68, Fig. 15, of the clamp 10 (or 66) is movable by the cylinder 59. A cylinder 67 monitors movement of the clamp 66 at the left hand end of the tracks. The clamp 66 comprises a support arm 69 rotatably mounted on the base 68 and carrying a stationary jaw 71 and a jaw 72 movable about a pivot 73. A cylinder 74 acts through a toggle 75 to open and close the jaws. The arm 69 is rotated by a rack 76, Fig. 14, acting on a pinion 77 on the arm 69, the rack 76 being driven by a cylinder 79. Electrical and pneumatic circuits, Figs. 18 and 20 (both not shown), are described for the operation of the machine in the manner described above with refernce to Fig. 2.