Patent EP-1048772-A1 (EP)
Inventor: KROPF MANFRED
IPC: D05B35/04
Filed: 1999-04-29
Abstract: The sewing machine, for automatic stitching of two fabric layers, has a clamp (23) to hold the materials together, and feed to the sewing machine (3). The fabrics are assembled by a transfer unit (9) to be passed to the clamp (23). The system has an assembly of up to seven sewing machines (3), each with a fabric clamp (23), charged by the fabric transfer (9). The sewing machines (3) are arranged in a circle. The clamps (23) are in a star-shaped layout, offset towards the center of circle. The fabric transfer unit (9) rotates at the center of the circle of sewing machines (3). A fabric feed acts with the transfer unit (9), which is charged with the fabric by an operative or automatically. The fabric feed has a length setting unit, ensure that the correct length is passed to the transfer unit (9). The length setting unit has at least one longitudinal strut a at least one lateral strut. The longitudinal strut has an end limit stop at its free end, for the fabric length, and the lateral strut has a handle. The fabric clamp (23) has two clamp units, linked together by a toggle lever which is operated to open and c the clamps. A spacer link is between the clamps, as a perforated rail, which grips at one clamp and a pin at the other clamp is through one of the holes in the rail according to the required clamping gap. The fabric clamp (23) has at least one transport sy (25), with a sliding rail where the clamps have a sliding movement. A drive moves the clamps, using a motor and a toothed belt transmission to at least one of the clamps. At least one clamp has a pin which engages an opening the transmission link. Each cl can have a double toggle lever, rotating on a pivot mounting, with a clamp pincer at one end to be moved in an opening and closi action with a fixed clamp pincer. An operating unit is at the other end of the double toggle lever to give it movement. The doub toggle lever is moved through a dead point between the open and closed settings, and the lever operating unit has a linear movem to set the required position of the clamp pincers. The lever operating unit has a horizontal U-shaped rail to take the operating unit, and the rail can be given a vertical movement to set the clamp positions. The fabric transfer unit (9) has a grip or clamp a folding mechanism, to fold the fabric into two layers. The folder has a folding blade in a flat support section, and a clamp w at least one rail and one clamping beam. The clamping beam is operated by a lifting mechanism using at least one toggle lever. T toggle lever has a further clamping or linkage lever which, in the dead point setting, presses the clamping beam against the rai The clamp (23) is linked to the buttonhole sewing machine (3) by a transport slide, with synchronized movements along a sliding section separated from other rail sections. The sliding rail section is locked to the sewing machine (3) by a U-shaped bonding plate, with a sliding movement along longitudinal rails, and rotation with a bonded rotating linkage plate for connection to the transport slide. A feed station passes the fabric to the transfer unit (9), with a folding blade of a folding unit. The fabric i taken off by a ring disk (15), under the clamp (23). An Independent claim is included for an automatic sewing machine operation, where a number of fabric workpieces are stitched simultaneously by a number of sewing machines (3). Each sewing machine (3) has clamp unit (23) which is charged by a fabric transfer unit (9). Preferred Features: The fabric folding is in two stages. In the first stage, a relatively light folding pressure is applied, and a relatively large folding pressure is applied in the second st The fabrics are fed separately, or are gripped and taken from a fabric stack.