GB1075947A - Improvements in or relating to adhesive applying apparatus - Google Patents

Abstract

1,075,947. Coating appartus. BOSTIK Ltd. Aug. 4, 1964 [July 23, 1963], No. 30622/64. Heading B2L. Apparatus for applying molten adhesive composition to a workpiece comprises a casing 10 provided with a recess 20 to which molten adesive composition is supplied, an applying wheel 22 mounted for rotation in the recess, a bearing which supports the wheel for rotation, and a continuous passage which extends in the casing and through the bearing to the recess, through which passage, when the apparatus is in use, a continuous stream of molten adhesive composition flows. As illustrated the casing 10 consists of a body portion 12 having a surface 13 of irregular contour, a rear portion 14 and a front portion 16. The wheel 22 is carried by a shaft 24 and has a circumferential surface 23 bounded by flanges 72, 74. The shaft 24 is mounted in two bearings a bush bearing 56 having interior and exterior axial grooves 102, 100; and a bearing block 58 there being a cup-shaped passage 124 between wheel 22 and block 58. The faces of wheel 22 bear against the respective faces of portions 14, 16; the face 15 of portion 14 having grooves 122, 126 therein. A stringer roll 26 carried by shaft 28 is located adjacent wheel 22, the shaft 28 being located in a bush bearing 114 having an axial groove 116, and the shafts 24 and 28 are driven from a suitable power source. Adjustable on the body portion 12 is a metering bar 30 and also a member 38 which co-operates with wheel 22 to divide the recess 20 into a first chamber 40 and a second chamber 42. Leading from chamber 40 is a recess 80 having located therein a control device 81 comprising a bellows 82 for operating a microswitch 94, said control device controlling the operation of a feed device (not shown) for feeding a rod of solid adhesive into the apparatus via bore 60. When in use the casing 10 is heated by elements 70 and shafts 24, 28 rotated by the power source. A solid rod of thermoplastic adhesive composition is fed into the bore 62 of bushing 64, passing into bore 60 and is progressively melted therein. The melted adhesive passes along passageway 66 into spiral groove 68 in the face 17 of portion 16, the side face of wheel 22 providing a pumping action to pass the adhesive into chamber 40. The chamber 40 is substantially closed to the atmosphere and adhesive is supplied thereto at a rate slightly in excess of that at which it is used so that the pressure in chamber 40 increases to a pressure greater than atmospheric. Two continuous streams of molten adhesive are urged by this pressure along first and second continuous passages to the second chamber 42 which is substantially at atmospheric pressure. The first stream is via the passages in bush bearing 56, bores 108, 110, bush bearing 114 to the face 17 of front portion 16 against which stringer roll 26 bears and thus into chamber 42, and the second stream is via passages in bearing block 58 and grooves 122, 126. Thus the bearings 56 and 114 and shafts 24, 28 and the various bearing surfaces are kept lubricated by a continuous stream of molten adhesive passing through. Extraneous adhesive from chamber 42 is fed back to chamber 40 through the clearance space between member 38 and wheel 22. As the pressure in chamber 40 increases the bellows 82 is compressed to operate microswitch 94 to stop the adhesive rod feeding device and when thereafter the pressure decreases to a predetermined value the bellows expands to cause the microswitch to again start the feeding device.