IMPROVEMENTS IN OR RELATING TO WELDING AND CUTTING

摘要

1323672 Seaming non-metallic sheet material; laminates BRITISH UNITED SHOE MACHINERY CO Ltd 3 June 1970 [4 June 1969] 28155/69 Headings B5K and B5N [Also in Divisions B6 and H5] A machine having two operating stations at each of which a high frequency operation can be performed on a workpiece comprises an upper platen 11 mounted for movement between the two stations, a workpiece supporting surface, at each station, provided by a platen 2, means for effecting relative movement of approach between the platens 2, 11 whereby, when the machine is in use, a tool can be pressed against a workpiece supported on the platen 2 to perform a high frequency operation on the workpiece, and means for connecting the platens 2, 11 to a high frequency electric source including a contact member 401 centrally disposed between the operating stations and which is engaged by one of two contact members 391 on the platen 11 according to at which station the platen 11 is positioned. The high frequency operation may be welding, cutting or embossing. If the layers are non-thermoplastic, welding is effected using an interposed thermoplastic adhesive. As shown in Fig. 1, a carriage 6 is mounted for movement along a beam 5 between left hand and right hand operating stations and supports an upper platen assembly comprising plates 9, 11 spaced apart by insulating sleeves 10. The upper platen may be lowered by hydraulic means 7 and is urged into retracted position by springs 12. The base 1 of the machine supports a H.F. generator (not shown) from an insulated output terminal of which extends a contact blade 401, Figs. 1 and 2, disposed between the two stations. Brackets 100 of electrically conducting material extend from opposite sides of the plate 11 and each supports a conducting plate 102 having a slot 104 in which a block 106 carrying a contact spring arrangement 391 slides. Each arrangement 391 can engage the blade 401 depending upon at which station the carriage 6 is positioned. Each arrangement 391 may be adjusted heightwise relative to the plate 11 and to the blade 401 by rotation of a shaft 110 by a head 112 so that the power of the H.F. field to be applied between the platens 2, 11 can be varied and the power applied at one station is variable independently of the pswer applied at the other station. The block 106 is locked in adjusted position by rotation of a shaft 114 having a head 116. A "die set" 118, Figs. 1 and 3, comprising means for supporting a tool and means whereby a workpiece can be positioned on the platen 2 in accurate location with a tool thus supported, is provided at each station and one is a mirror image of the other. Each die set 118 comprises a plate 122 supported by a bracket 120 and having an arm 126 pivotally mounted thereon by a pin 124 to extend across the width of the station in operative position. A tool (not shown) can be supported on a frame 128 supported by the arm 126. For ensuring that a tool is held by the frame 128 in correct relationship with a workpiece, the arm 126 has a projection 125 having a surface 127 to engage a stud 129 secured to the plate 122. To facilitate movement of the frame 128 into and out of its operative position, a spring 130 acts between a fixed pillar 4 and a stub shaft 132 on the arm 126 which is provided with a pivot pin 134 having an eccentric flange portion 136 carrying the shaft 132. Rotation of the pin 134 varies the tension in the spring 130. For locking the pin 134 in an adjusted position, the pin carries an arm 138 supporting a plunger 140 engagable in one of a number of depressions 142 in the arm 126. The die set 118 also comprises a frame 144 in which means (not shown) is provided for locating a workpiece in correct relationship with a tool mounted in the frame 128. This locating means may comprise a template having a cut-out shaped to the shape of the workpiece. In a modification (not shown), the spring 130 is replaced by a piston and cylinder whereby, at the end of an operation, after the upper platen has been raised, the die set can be opened with intervention from the operator. Transparent sliding guards 146, 148 are associated with the left hand and right hand stations, respectively, and each operates a microswitch B17, B18, respectively, by a cam surface 150, 152. The arrangement is such that operation of the machine at one station cannot begin until the microswitch associated with that station is closed by the associated slide. A paper feed machanism (not shown) may be provided whereby, under the control of the operator, barrier paper may be fed between the workpiece and the platen 2. For alternate station working, the operator locates a workpiece in the die set of, e.g. the left hand station, with a tool supported thereon, closes the die set, closes the slide 146 to trip the microswitch B17 and presses a switch B2. Tripping the switches B2, B17 "calls" the carriage 6 to the l.h. station at which a H.F. operation is initiated. Once the carriage 6 has reached the l.h. station, the slide 148 can be opened and a further operation prepared for at the r.h. station. After preparation, the operator closes the slide 148 to trip the switch B18 and presses a switch B3. Tripping the switches B3, B18 "calls" the carriage 6 to r.h. station, however, if the operation at the l.h. station is not complete, the electrical control circuit "remembers" this call signal and effects movement of the carriage upon completion of the operation. If at any time during travel of the carriage 6, either slide 146, 148 is opened, this travel is arrested and can be restarted only by closing the slide and pressing the appropriate switch B2 or B3. For single station working, the operator switches a switch B15 or B16 according to the station at which he wishes to work. Assuming the l.h. station to be selected, the carriage 6 is traversed to the r.h. station whilst the l.h. station is prepared. The slide 146 is closed and the switch B2 pressed to "call" the carriage 6 to the l.h. station. At the end of the operation, the upper platen assembly rises and the carriage 6 automatically moves to the r.h. station to allow the l.h. station to be re-prepared.