US4358979A — Apparatus for cutting plastic film

Claim 1

Independent Claim 122 words

Apparatus for perforating plastic film which comprises: a metal blade having an elongate serrated cutting edge; means for reciprocating the blade through a cutting cycle; a readily penetrable back-up member aligned with cutting blade and having a surface for supporting film thereon and grooves formed therein particularly shaped to receive the serrated cutting edge in close conformity, said grooves being formed by reciprocating said blade through a sufficient number of cycles to permanently shape the grooves in said back-up member by penetration of said blade to a substantial depth; whereby reciprocation of said blade through a cutting cycle causes the blade to penetrate film supported on said support surface, to enter said particularly shaped grooves, and to return to a retracted position.

Claim 2

Dependent Claim 122 words

Apparatus for perforating plastic film which comprises: a metal blade having an elongate serrated cutting edge; means for reciprocating the blade through a cutting cycle; a readily penetrable back-up member aligned with cutting blade and having a surface for supporting film thereon and grooves formed therein particularly shaped to receive the serrated cutting edge in close conformity, said grooves being formed by reciprocating said blade through a sufficient number of cycles to permanently shape the grooves in said back-up member by penetration of said blade to a substantial depth; whereby reciprocation of said blade through a cutting cycle causes the blade to penetrate film supported on said support surface, to enter said particularly shaped grooves, and to return to a retracted position.

Claim 3

Dependent Claim 23 words

Apparatus as defined in claim 1 wherein the blade is made of a metal having a hardness of at least Rockwell C 50.

Claim 4

Dependent Claim 40 words

Apparatus as defined in claim 1 wherein the blade comprises a metal member having a plurality of teeth and being flash electroplated with chromium to provide the tips of the blade teeth with convex edges to better penetrate the film.

Claim 5

Dependent Claim 51 words

Apparatus as defined in claim 1 wherein the blade has formed between at least part of adjacent teeth of the serrated cutting edge slots which extend transversely with respect to the serrated cutting edge, and wherein the cutting stroke is such that a portion of the slots enter the back-up member.

Claim 6

Dependent Claim 45 words

Apparatus as defined in claim 4 wherein the back-up member is positioned in relation to the blade such that at least a portion of the slots formed in the blade remain above the back-up member in all positions of the blade through the cutting stroke.

Claim 7

Dependent Claim 37 words

Apparatus as defined in claim 1 wherein the back-up member is balsa wood positioned in relation to said blade such that the grains of the balsa wood are aligned parallel to the cutting action of the blade.

Claim 8

Dependent Claim 104 words

Apparatus for perforating plastic film which comprises: a serrated metal blade having an elongate serrated cutting edge having a Rockwell hardness of at least C 50, said blade being reciprocable from a retracted position through a cutting stroke; and a soft wood back-up member aligned with the blade for supporting plastic film thereon during the cutting stroke, said back-up member being readily penetrable and deformable by said blade and being sufficiently rigid to provide substantially unyielding support for the film during blade penetration thereof and having grooves of a substantial depth formed therein for receiving the blade by the action of blade penetration thereof.

Claim 9

Dependent Claim 104 words

Apparatus for perforating plastic film which comprises: a serrated metal blade having an elongate serrated cutting edge having a Rockwell hardness of at least C 50, said blade being reciprocable from a retracted position through a cutting stroke; and a soft wood back-up member aligned with the blade for supporting plastic film thereon during the cutting stroke, said back-up member being readily penetrable and deformable by said blade and being sufficiently rigid to provide substantially unyielding support for the film during blade penetration thereof and having grooves of a substantial depth formed therein for receiving the blade by the action of blade penetration thereof.

Claim 10

Dependent Claim 34 words

Apparatus as defined in claim 7 wherein the blade serrations are shaped and spaced to perforate the film supported on the back-up surface to provide a longitudinally spaced perforations extending transversely along the film.

Claim 11

Dependent Claim 26 words

Apparatus as defined in claim 8 and further comprising a heater element positioned adjacent the blade to heat seal the film adjacent the longitudinally spaced perforations.

Claim 12

Dependent Claim 39 words

Apparatus as defined in claim 9 wherein the blade comprises a metal member having a plurality of teeth and flash electroplated with chromium to provide the tips of the blade teeth with convex edges to better penetrate the film.

Claim 13

Dependent Claim 37 words

Apparatus as defined in claim 10 wherein the back-up member is balsa wood positioned in relation to said blade such that the grains of the balsa wood are aligned parallel to the cutting action of the blade.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1985-11-15	1986-05-17	1986-11-16	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1989-11-15	1990-05-17	1990-11-16	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1993-11-15	1994-05-17	1994-11-16	$7700.00	Window Closed / Lapsed

Apparatus for cutting plastic film

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