Method and apparatus for scoring plastic sheet material
OwnerBenjamin Rosenberginventor
Life of this patent
Estimating the term…
Abstract
Plastic sheet material used for forming box blanks are provided with soft, bendable score lines by applying frictional heat through rapid vibration. The sheet material is clamped under high pressure between a resilient make-ready and a scoring tool, and is subjected to the vibratory action which generates frictional heat sufficient to melt the plastic material at the engaged interface, thereby forming a score line along which the sheet material may be bent to form an assembled box. A completed box blank may be formed in a single operational step, by cutting the box, impressing the score lines, and impressing embossments, if required, simultaneously in a single operational cycle of seconds duration.
Claims19
A method for forming a container blank having cut edges and flexible score lines, comprising the steps of:
- providing a thermoplastic sheet capable of being formed into said container blank,
- providing at least one scoring tool member and an elastomeric make-ready member having a flat surface,
- bringing said members to an inoperative position in which said members face each other and are spaced apart,
- inserting said thermoplastic sheet between said members,
- bringing said members together to an operative position in which said scoring tool member engages a face of said thermoplastic sheet and presses the engaged portion of said sheet against the flat surface of said make-ready member under substantial pressure, whereby said sheet adheres to said elastomeric make-ready member at the interface area with said scoring tool,
- vibrating one of said members while maintaining the other member stationary to provide a rapid reciprocating movement between the scoring tool member and the engaged interface portion of said thermoplastic sheet in a direction parallel to the face of said thermoplastic sheet, said reciprocating movement being sufficient to generate frictional heat of an intensity to soften said engaged sheet portion and cause the latter to penetrate deep into said elastomeric make-ready, whereby to form a flexible score line which is intended into one face of said sheet and projects from the opposite face thereof, and
- separating said members to their inoperative position and allowing said sheet to cool while maintaining it in substantially flat condition.
Apparatus for forming a container blank having cut edges and flexible score lines from a flat thermoplastic sheet, comprising:
- a scoring tool member,
- an elastomeric make-ready member having a flat surface,
- means for mounting said members for relative movement between an inoperative position in which said members face each other and are spaced apart for insertion of said thermoplastic sheet therebetween, and an operative position in which said scoring tool member engages a face of said thermoplastic sheet and pressed the engaged portion of said sheet against the flat surface of said make-ready member under substantial pressure, whereby said sheet adheres to said elastomeric make-ready member at its engaged interface area with said scoring tool,
- means for vibrating one of said members while maintaining the other member stationary to provide a rapid reciprocating movement between the scoring tool member and the engaged interface portion of said thermoplastic sheet in a direction parallel to the face of said thermoplastic sheet, said reciprocating movement being sufficient to generate frictional heat of an intensity to soften said engaged interface sheet portion and cause the latter to penetrate deep into said elastomeric make-ready, whereby to form a flexible score line which is indented into one face of said sheet and projects from the opposite face thereof, and
- means for separating said members to their inoperative position to enable said thermoplastic sheet to cool while maintained in substantially flat condition and for removal of said sheet from between said members.
Dependencies are inferred from the claim text.