Method of and apparatus for butt splicing self-adherent sheet material

摘要

Sheets of self-adherent material are buttspliced by clamping edge portions to be spliced together in spaced parallel relation by exerting clamping pressure between two pairs of pivotally movable jaws 12, 13, 21, 22, one pair clamping each edge portion, and moving the jaws pivotally to bring the edge portions intimately into contact by an arcuate motion to exert mutual pressure on the edge portions to splice them. The uncut edges of bias-cut pieces from a calendered strip of tyre cord fabric in which strip the cords are parallel to the longitudinal edges thereof are spliced together to form a fabric with parallel cords extending diagonally thereof. In a modification, the lines of severance are perpendicular to the cords. The splicing head D supporting a toggle action splicer unit E is situated between infeed and outfeed sections B, C respectively. The head D comprises upper clamping jaws 12, 13 mounted on blocks 9, Fig. 3, rigidly mounted on shafts 7 to turn therewith. Grippers 14, 15, preferably metal plates, are mounted on the jaws 12, 13 and have fingers 16, 17 respectively, which interfit during the splicing operation. Lower clamping jaws 21, 22 are mounted on blocks 20 each rigidly mounted on a sleeve 18 pivoted to an end 8 of the shaft 7. Grippers 23, 24 are mounted on the jaws 21, 22 and have interfitting fingers 25, 26, Fig. 8. The grippers 14, 15, 23, 24 preferably have opposed roughened or serrated faces 27 to grip the fabric. An aligning bar 31 is mounted on brackets 30 on a beam 29 and is tapered to provide a narrow lower edge which lies between the grippers 14, 15 when they are in their uppermost positions, Fig. 4. Grooves 32 are provided in the bar 31 to accommodate the fingers 16, 17. Resistance to downward movement of the jaws 21, 22 is provided by a number of inflatable pneumatic bags 44 resting on a plate 42 and acting on a plate 45 to which a web 46 is attached. The web 46 simultaneously engages the inner edges of the jaws 21, 22. Adjustable stops 47, Fig. 3, are provided to limit the downward movement of the jaws 21, 22 and the uppermost position of these jaws is determined by adjustable screws 50 engaging bars 51. The section B comprises a plurality of narrow feed belts 60 driven by rollers 62 and which pass over idle rollers 66 carried by adjustable supports 68 positioned in a line extending across the section at approximately the same angle as that at which the head D is set. Each belt 60 is maintained under tension by a roller 70 mounted on a pivoted arm 71 against which a rod 73 loaded by a spring 72 bears. A rail 74, Fig. 1, is provided to guide the infed fabric. Idler rollers 75 provided with bristles 76 on the peripheries thereof urge the fabric into engagement with the rail 74. The section C comprises a take-off table 77, attached to rods 80, 81 slidable in guides 78, 79. A cylinder 83 shifts the table 77. A pull roller 85 engaged by an idler roller 89 advances the spliced strip after each splicing operation. A metal guide strip 90 and a wrinkler bar 91 are also provided. In operation, the jaws 12, 13, 21, 22 are initially in the position shown in Fig. 4. The already formed strip is positioned with its trailing edge engaging the bar 31 and the roller 85 is stopped. A piece of fabric to be spliced is placed on the belts 60 which are driven to advance the piece to abut the bar 31. The belts 60 are stopped and four cylinders 36 are actuated to press the jaws 12, 13 downwardly to grip the pieces to be spliced. The grippers 14, 15, 23, 24 are then swung simultaneously downwardly to the position of Fig. 5, whilst the edges are maintained in horizontal alignment and subjected to the toggle action of the grippers for a sufficient time to allow the uncured rubber to form a splice. At the beginning of the downward movement of the jaws, pressure in the air bags 44 is relieved so that the pressure exerted by the jaws on the work is gradually decreased, a valve 99 (not shown), being set to obtain a predetermined minimum pressure in the bags. Biasing springs (not shown), return the pistons 39 of the cylinders 36 to their uppermost positions and lift the jaws 12, 13 whilst the jaws 21, 22, remain horizontal, Fig. 11 (not shown). The roller 85 is driven to pull out a length of spliced strip corresponding to the width of the piece spliced thereto and simultaneously the cylinder 83 pulls the table 77 away from the head D to move the trailing end of the strip clear of the grippers. Pressure is applied to the air bags 44 to raise the jaws 21, 22 to the position of Fig. 4. The roller 85 is stopped and the cylinder 83 is actuated in the reverse direction to move the table 77 towards the head D to position the trailing end of the strip against the bar 31. The next piece of fabric to be spliced is placed upon the belts 60 and the cycle repeated. The pneumatic system of the apparatus and an electrical system for controlling the successive operations are described in the Specification.