GB758717A - Improvements in or relating to machines organised for the treatment of sewn seams inflexible workpieces - Google Patents

Abstract

A machine for applying flexible thermoplastic coating material to sewn seams in flexible workpieces such as the back seam in shoe uppers, has a receptacle in which the coating material is melted, a pump which circulates and extrudes it in a viscous state through a passage ending in a nozzle past which a workpiece is progressively carried by feed rolls which engage it on opposite sides of the seam and move it over a support, and a device responsive to the approach of a workpiece towards the nozzle to control the supply of coating material therethrough. As shown, a workpiece W, comprising a pair of shoe quarters stitched together at S and everted, leaving a seam ridge R is supported on a stationary disc 10 and a supporting roll having freely rotatable frusto-conical side portions 12. A guide 14 is received in the seam crease, and its end 15 engages a recess 17 in the disc 10 to prevent rotation thereof. A grooved feeler 16 engages the upper W shortly in advance of a notched nozzle which extrudes coating material on the workpiece. Feed rolls 22 stretch the workpiece over the supports 10, 12 and carry it past the nozzle. The roll 10 is mounted on a pivot 51 in a spring-urged plunger 52 yieldably mounted in a carrier 54 which is secured to a plate pivoted in lugs 58 on a base 24, and lockable in operative position by a spring-pressed bolt 60. The base 24 also carries standard 26 which supports extruding means E and a bracket 30 which supports the feed rolls 22 and gearing by which these are driven in the same direction by a shaft 42 which is driven through a sprocket and chain 44 by a power shaft 46 having fast and loose pulleys 48 and 50. One of the feed rolls 22 is fixed axially, the other being spring-urged towards it. The extruding means E includes a receptacle 100 provided with a thermostat-controlled <PICT:0758717/III/1> <PICT:0758717/III/2> <PICT:0758717/III/3> <PICT:0758717/III/4> heating unit 104. A gear pump 94 is driven from the shaft 42 through a crossed belt 115, pulley 114, shaft 112, spiral gears and a vertical shaft 110, and its output is delivered under pressure determined by a thumb-piece 118 which controls a by-pass valve, to the passage 92 of the nozzle. A valve 81 closed by a spring-loaded conical head 82 controls the flow of material to the nozzle. The stem 84 of the valve-head 82 is connected by levers 122, 123, pinned to a shaft 128, to the core of a solenoid 120, which is energized on operation of a sensitive switch 156. This is effected by the feeler 16, the rod 140 on which it is mounted carrying an arm 144 connected by an adjustable link 148 to a bell-crank lever 150 positioned beneath the button 154 of the switch 156. Movement of the feeler 16 by a workpiece thus causes supply of the coating material to the nozzle to be initiated before the workpiece reaches the latter, and to be cut off before the workpiece has passed from beneath it. Specifications 404,647, [Group XV] and 707,407, are referred to.