Method and apparatus for scrap removal from rotary dies
OwnerAlan R. Pfaff, JR.inventor
Life of this patent
Estimating the term…
Abstract
An improved rotary die cutting apparatus and method for removing scrap material from work pieces such as paperboard blanks. One of the dies of a pair of rotary cutting dies is provided with gripper elements that extend over at least a portion of the area of the die corresponding to the areas over which the scrap portions are generated. The gripper elements grip, without piercing completely through, the scrap portions generated by the cutting operation of the dies. A stripping knife extends across the die carrying the scrap portions at a height above the gripper elements that provides clearance between the gripper elements and the stripping knife but contacts the scrap portions retained on the gripper elements.
Claims19
An improved rotary die cutting apparatus for cutting a moving web of material into blanks, said apparatus comprising:
- a pair of carrier cylinders;
- upper and lower rotary dies removably mounted to said carrier cylinders, at least one of said rotary dies having cutting elements thereon adapted to generate blanks and scrap portions from the moving web of material;
- gripping elements extending from at least one of said rotary dies, said gripping elements registering with said scrap portions as said rotary dies rotate, said gripping elements sized and positioned so as not to pierce completely through said scrap portions, said gripping elements having the shape of truncated cones having an undercut upper portion;
- and
- a stripping knife having a blade edge for contacting the leading edges of said scrap portions as said scrap portions are stripped away from said gripping elements.
An improved rotary die cutting apparatus for cutting a moving web of material into blanks, said apparatus comprising:
- upper and lower rotary dies, at least one of said rotary dies having cutting elements thereon adapted to generate blanks and scrap portions from the moving web of material;
- gripping elements extending from at least one of said rotary dies, said gripping elements registering with said scrap portions as said rotary dies rotate, said gripping elements sized and positioned so as not to pierce completely through said scrap portions, said gripping elements arranged in a closely spaced pattern in a range of about 25 to about 400 gripping elements per square inch;
- and
- a stripping knife having a blade edge for contacting the leading edges of said scrap portions as said scrap portions are stripped away from said gripping elements.
The apparatus of claim 111 and further comprising a tool carrying cylinder and wherein at least one of said rotary dies is removably mounted to said tool carrying cylinder.
A method for removing scrap pieces from blanks cut from a moving web of material in a rotary die cutting operation, comprising the steps of:
- advancing the web of material between upper and lower rotary dies having cutting elements on at least one of said rotary dies;
- forming blanks and scrap pieces from said web material by cutting the web material with said cutting elements;
- gripping said scrap pieces onto gripping elements positioned on one of said rotary dies;
- and
- stripping said scrap pieces from said gripping elements with a stripping knife.
Dependencies are inferred from the claim text.