Flat embossing machine with a foil loop store

An embossing machine for embossing a flat material (5) comprising the combination of

• a flat press (2) with an embossing table (3) and a tool plate (4);
• control means for operating said press in a press cycle (TO) comprising alternately an embossing phase (TP) and an embossing-free phase (TL);
• a plurality of elongated foil webs (6.1, 6.2, 6.3) for conveying material to be embossed;
• means for separately guiding said plurality of foil webs from unwinding rolls (7) across said embossing table to a foil removal device (8);
• at least one foil loop store (10) having a differential pressure device (30) for forming at least one foil loop (12) in said foil webs (6) by establishing an air pressure difference across said foil webs;
• a plurality of foil feed devices (24.1, 24.2) on one side of said press and tensioning devices (25) for exerting a tension force on said foil webs on the other side of said press for feeding said foil webs at different feed speeds (VV1, VV2);
• said control means further comprising means for controlling said foil feed devices and said tensioning devices such that said foil web is kept stationary with a longitudinal web speed of zero in an embossing position on said embossing table during the entire duration of said embossing phase (TP) and such that said at least one foil web is longitudinally advanced to a next embossing position during said embossing free phase (TL) by continuously accelerating and then continuously decelerating to zero web speed said foil webs, said webs having feed speeds (VV1, VV2) at said embossing location, an unwinding web speed V7 at said unwinding roll (7) and a web speed V8 at said foil removal device, wherein said feed speeds .noteq.V7.noteq.V8 during at least portions of said press cycle;
• said control means controlling said at least one foil loop store to increase and decrease the size of said at least one loop in response to inequalities of said speeds to compensate for differences in said speeds and to permit movement of said foil webs.

A flat embossing machine for a flat material to be embossed comprising the combination of

• a flat press (2) with an embossing table (3) and a tool plate (4);
• control means for operating said press in a press cycle (TO) comprising alternately an embossing phase (TP) and an embossing-free phase (TL);
• at least one elongated foil web (6) for conveying material to be embossed;
• means for guiding said at least one foil web from an unwinding roll (7) across said embossing table to a foil removal device (8),
• at least one foil loop store (10) having a differential pressure device (30) for forming at least one foil loop (12) in said at least one foil web (6) by establishing an air pressure difference across said at least one foil web, said at least one loop store including guide walls having means for reducing frictional forces acting on said foil web as said web passes over said guide walls so that said frictional force along an entry wall of said loop store is smaller than frictional force on an exit wall thereof;
• a foil feed device (24) on one side of said press and a tensioning device (25) for exerting a tension force on said at least one foil web on the other side of said press;
• said control means further comprising means for controlling said foil feed device and said tensioning device such that said at least one foil web is kept stationary with a longitudinal web speed of zero in an embossing position on said embossing table during the entire duration of said embossing phase (TP) and such that said at least one foil web is longitudinally advanced to a next embossing position during said embossing free phase (TL), said web having a feed speed VV at said embossing location, an unwinding web speed V7 at said unwinding roll (7) and a web speed V8 at said foil removal device, wherein VV.noteq.V7.noteq.V8 during at least portions of said press cycle;
• said control means controlling said at least one foil loop store to increase and decrease the size of said at least one loop in response to inequalities of said speeds to compensate for differences in said speeds and to permit movement of said at least one foil web.

A flat embossing machine for embossing a flat material comprising the combination of

• a flat press (2) with an embossing table (3) and a tool plate (4);
• control means for operating said press in a press cycle (TO) comprising alternately an embossing phase (TP) and an embossing-free phase (TL);
• said flat press comprising a bent lever press and means for adjusting bent lever geometry of said press so that movement of said embossing table and said embossing phase are variable;
• at least one elongated foil web (6) for conveying material to be embossed;
• means for guiding said at least one foil web from an unwinding roll (7) across said embossing table to a foil removal device (8),
• at least one foil loop store (10) having a differential pressure device (30) for forming at least one foil loop (12) in said at least one foil web (6) by establishing an air pressure difference across said at least one foil web;
• a foil feed device (24) on one side of said press and a tensioning device (25) for exerting a tension force on said at least one foil web on the other side of said press;
• said control means further comprising means for controlling said foil feed device and said tensioning device such that said at least one foil web is kept stationary with a longitudinal web speed of zero in an embossing position on said embossing table during the entire duration of said embossing phase (TP) and such that said at least one foil web is longitudinally advanced to a next embossing position during said embossing free phase (TL), said web having a feed speed VV at said embossing location, an unwinding web speed V7 at said unwinding roll (7) and a web speed V8 at said foil removal device, wherein VV.noteq.V7.noteq.V8 during at least portions of said press cycle;
• said control means controlling said at least one foil loop store to increase and decrease the size of said at least one loop in response to inequalities of said speeds to compensate for differences in said speeds and to permit movement of said at least one foil web.