Patent GB-1149438-A (GB)
Title: Method of and apparatus for butt-splicing
IPC: B29C65/00
Filed: 1967-07-28
Abstract: 1,149,438. Seaming non-metallic sheet material. PIRELLI S.p.A. 28 July, 1967 [4 Aug., 1966], No. 34756/67. Heading B5K. Two ends are butt spliced by positioning the two ends so that the end or section faces of the ends are positioned close to each other; either, bringing an elastic element 60 or 70, previously stretched in a certain direction, into contact with at least one surface or surface portion of at least one of the ends, or bringing an elastic element into contact with at least one surface or surface portion of at least one of the ends and thereafter stretching the element in a certain direction; and exerting a force on said one surface or surface portion, tangentially thereto and acting in a certain direction which (at least at the instant of exertion thereof) forms an angle with the splicing line, by releasing at least a part of the power stored in the elastic element 60 or 70. In one embodiment, Figs. 2 and 6, to butt splice the ends of flexible strips of adhesive material, e.g. tyre cord fabric, there are provided two elastic elements constituted as membranes 60, 70 which are initially stretched under tension. The first strip is fed into the apparatus and caused to slide over a plate 76, a plate 64, the membrane 60, a plate 65, a chamber (77), Figs. 1 and 4 (both not shown), and on to a stationary conveyer belt (78). The strip is arrested when its trailing edge reaches the median zone of the membrane 60 and is held in this position by suction applied by the chamber (77). The second strip is then fed into the apparatus until its leading edge has almost contacted the trailing edge of the first strip. Fluid under pressure is supplied to a chamber 39, Fig. 2, to move a piston 38 and guides 23 connected thereto downwardly. Stems 16 supported by the guides 23 on small wheels 22 are thus permitted to move downwardly to move an upper ledger comprising two sectors 17<SP>1</SP>, 17<SP>11</SP>, Fig. 6, carrying the membrane 70 downwardly until this membrane reaches the strips. Compressed fluid is supplied to cylinders 24 to force the stems 16 downwardly within guides 15 to compress the strips between a lower splicing plate supporting sector 14<SP>1</SP>, 1411 and the upper ledger. The suction applied to the chamber (77) is then interrupted and the sectors 14<SP>1</SP>, 14<SP>11</SP> and 17<SP>1</SP>, 17<SP>11</SP>, Fig. 6, are moved towards each other simultaneously by supplying compressed air to a chamber 40, Fig. 2, to lower a piston 44 which drags downwardly a toggle joint 46 connected thereto by a stem 45. The downward movement of the joint 46 causes levers 49, 50 to rotate about a pin 51 and compel the sectors 14<SP>1</SP>, 1411, to extensions (54), (55), Fig. 4 (not shown), of which these levers are pivotally connected, to move horizontally towards each other. This movement is guided by guides 27, Fig. 2, sliding on stems 28. Since the stems 16 carry the guides 15 integral with the sectors 14<SP>1</SP>, 14<SP>11</SP> and guides 18 integral with the sectors 17<SP>1</SP>, 17<SP>11</SP>, the downward movement of the joint 46 simultaneously moves the sectors 17<SP>1</SP>, 1711 towards each other. The horizontal movements of the sectors 14<SP>1</SP>, 14<SP>11</SP>, 17<SP>1</SP>, 17<SP>11</SP> lead to butt compression of the strips and release of tension in the membranes 60, 70 which thus exert symmetrical forces on the strips directed towards the splicing line. During these movements, fluid under pressure is supplied to tubular bags 61, 71 which expand and apply pressure to the strips in directions normal to their faces to strengthen the splice. After splicing, the upper ledger is raised by supplying fluid to the chamber 39 and permitting the discharge of fluid from the chambers 24. Simultaneously, fluid is discharged from the bags 61, 71 and air is supplied through ducts 65<SP>1</SP>, 65<SP>11</SP>, 73<SP>1</SP>, 73<SP>11</SP> and other passages to detach the spliced strips from the membranes 60, 70. While the upper ledger is being raised the sectors 14<SP>1</SP>, 14<SP>11</SP> and 17<SP>1</SP>, 1711 are moved away from each other by supply of fluid to the chamber 40 to lift the joint 46. The belt (78) is actuated to remove the joint or the strips from the apparatus. The apparatus is rotatable about the axis of a cylinder 13 secured to the base 10 so that the apparatus is adjustable to the angle of cut if the strips to be spliced are cut on the bias. In another embodiment, Figs. 7 and 8, to splice the ends of two rigid hollow bars 112, 113, rubber strips 104, 111 are stretched by spacing clamps 105, 105<SP>1</SP>, 106, 1061 apart. The bars 112, 113 are inserted between guides 102, 103 with the ends thereof, previously coated with adhesive, positioned a short distance apart. The strip 111 is lowered and, thereafter, the clamps are moved towards one another to allow the strips 104, 111 to shrink and exert tangential forces in the direction of the splicing line until the bars are joined. In modifications (not shown), the elastic elements may act upon two faces of only one of the two ends to be spliced or only one face thereof, e.g. one end of each elastic element may remain fixed whilst the other end is moved towards and away therefrom. The elastic elements may comprise a plurality of strips disposed side-by-side so that the width of the unit formed thereby is adjustable in accordance with the width of the strips to be spliced or so that their disposition is adjustable, e.g. to enclose completely bars to be spliced. The elastic elements may be stretched in a direction different to that forming an angle of 90 degrees to the splicing line. If the materials to be spliced are not self-adhesive they may be made adhesive by thermal, chemical or electrical treatment or by coating with adhesive.