Patent GB-1376894-A (GB)
Title: Machines suitable for use in performing hf operation on workpieces
IPC: B29C65/48
Filed: 1970-12-02
Abstract: 1376894 Seaming non-metallic sheet material BRITISH UNITED SHOE MACHINERY CO Ltd 1 Dec 1971 [2 Dec 1970] 57151/70 Headings B5K and B5N [Also in Division B6] A machine for performing a HF welding operation on a workpiece V comprising upper and lower platens, means for effecting relative movement of approach between the platens whereby, when the machine is in use, a die 76<SP>1</SP> and a workpiece supported between the platens can be pressed so that an operation is performed by the die on the workpiece, means for limiting the amount of relative movement of approach, heating means 316 whereby a die 76<SP>1</SP> supported as aforesaid can be heated, and means to connect the platens, which serve as electrodes, to a high frequency electric cource. The HF operation may be a welding, welding and cutting, or an embossing operation. A machine for applying an applique layer to a base layer, e.g. a shoe vamp V, with or without the interposition of a separate heat-activatable adhesive layer, comprises two stations at each of which there is provided a lower platen 44 comprising an aluminium block having an aluminium wear sheet thereon to support a workpiece. An upper platen (not shown), is movable between the two stations and is movable, by an hydraulic ram, towards and away from the lower platen at each station. A workpiece locating and die supporting means 48 is provided at each station so that a die 76<SP>1</SP> on a plate 300 supported on an arm 54 thereof overlies the platen 44. The die 76<SP>1</SP> is secured to the plate 300 by clamping screw 310 engaging blocks 308 on the die 76<SP>1</SP>, the blocks 308 being received in two of eight apertures 304 in the plate 300. A number, e.g. twelve, of electric cartridge heaters 316 are received in the plate 300 to heat blade portions 82<SP>1</SP> of the die 76<SP>1</SP>. Each platen 44 is provided with two grooves 320 inclined at 322 at opposite ends and which accommodate insulating strips 324 to the underside of which, at each end, are secured wedges 326 supporting the strips on the inclined surfaces 322. Thus, movement of the strips 324 in the grooves 320 alters the amount by which they project above the work surface of the platen 44. This movement is effected by rotation of a pin 330 acting on one member 326 urged into engagement therewith by a spring 332, the rearward ends of the strips 324 being interconnected by a link 336. In use, at one station, the operator mounts a die 76<SP>1</SP> on the plate 300 and locates on the platen 44 a sheet of pattern board (not shown), constituting a locating means and having a cut-out shaped to the workpiece V. Four studs 338, spring urged upward, resiliently support the pattern board. The die 76<SP>1</SP> is brought into engagement with the workpiece, the height of the elements 324 having been adjusted so that movement of the die is arrested when the edges of the blade portions 82<SP>1</SP> are spaced from the workpiece supporting surface by the depth of the base layer. The HF operation is performed so that the applique layer is sealed to the base layer along the outline of the portions 82<SP>1</SP> and is cut by the portions 82<SP>1</SP> to the pattern of the die. In a modification (not shown), the arm 54, the plate 300 and the studs 338 are omitted. Mounted on the machine bed, at each station, is a heat insulating board on which the lower platen, comprising an aluminium block with an aluminium wear sheet thereon, is secured. The lower platen is earthed and the aluminium block is provided with electric cartridge heaters. The workpiece is located in a cut-out of a sheet of pattern board pivotally mounted on the machine bed between operative and inoperative positions. An insulating sheet is also pivotally mounted to the machine bed so as to overlie the workpiece and the pattern board in operation.