US-12617131-B2 - Continuous roll molding system and method; frangible cap strip and method of making using continuous roll molding

US12617131B2US 12617131 B2US12617131 B2US 12617131B2US-12617131-B2

Abstract

A continuous roll molding system and method are provided. The system and method may be for manufacturing parts and may include conveying a thermoplastic material through a sheet die to form a thermoplastic sheet material, conveying the thermoplastic sheet material through a calendering system, and conveying the thermoplastic sheet material through a continuous roll molder to form the thermoplastic sheet material into parts. Parts formed by the continuous roll molding system and method may include frangible cap strips.

Inventors

FREDERICK WILLIAM LAMB
FREDERICK WILLIAM LAMB, II

Assignees

PNEU-TOOLS, INC.

Dates

Publication Date: 20260505
Application Date: 20250121

Claims (17)

1 . A method of forming a strip of frangibly connected parts comprising: providing a thermoplastic sheet material; and conveying the thermoplastic sheet material through a continuous roll molder comprising a first roller and an opposing second roller, the first roller comprising a circumference, and further comprising a first series of first shapes arranged around the circumference of the first roller, the second roller comprising a circumference, and further comprising a second series of second shapes arranged around the circumference of the second roller, the first and the second rollers configured so that the first series of first shapes opposes the second series of second shapes to form the strip of frangibly connected parts comprising a three dimensional shape on both sides of the strip of frangibly connected parts, a first shape of the first series of first shapes and a corresponding second shape of the second series of second shapes are configured to form a first part of the strip of frangibly connected parts, at least one of the first shapes and the second shapes comprising a projection portion projecting radially from the circumference of the respective first and second roller and is configured for imparting a three-dimensional shape on a surface of the first part of the strip of frangibly connected parts, the first shape of the first series of first shapes further comprising one or more knives configured to cut the thermoplastic sheet material, the second shape of the second series of second shapes further comprising one or more anvil surfaces against which the one or more knives of the first shape of the first series of first shapes are configured to cut against, adjusting a temperature control system to maintain a gap between the one or more knives and the one or more anvil surfaces, wherein the continuous roll molder further comprises one or more channels configured to receive a temperature-controlled fluid of the temperature control system; cutting the thermoplastic sheet material into the strip of frangibly connected parts utilizing the one or more knives of the first shape of the first series of first shapes and the one or more anvil surfaces of the second shape of the second series of second shapes; forming a frangible zone between adjacent parts of the strip of frangibly connected parts utilizing the one or more knives of the first shape of the first series of first shapes and the one or more anvil surfaces of the second shape of the second series of second shapes; separating the strip of frangibly connected parts from a waste thermoplastic sheet material such that the strip of frangibly connected parts and the waste thermoplastic sheet material are separated after cutting the thermoplastic sheet material into the strip of frangibly connected parts.
2 . The method of claim 1 , wherein providing a thermoplastic sheet material comprises conveying a thermoplastic material through a sheet die to form a thermoplastic sheet material, the thermoplastic sheet material comprising a first surface, a second surface, and an intermediate portion disposed between the first surface and the second surface.
3 . The method of claim 2 , wherein the thermoplastic sheet material comprises a single layer.
4 . The method of claim 2 , further comprising: between conveying the thermoplastic sheet material through the sheet die to form a thermoplastic sheet material and conveying the thermoplastic sheet material through the continuous roll molder: conveying the thermoplastic sheet material through a calendering system configured to reduce a temperature of the first surface and the second surface when conveying the thermoplastic sheet material through the calendering system.
5 . The method of claim 1 , wherein the continuous roll molder comprises a bar and a nip roller, the bar configured to receive the strip of frangibly connected parts being conveyed along a first stream released from the one or more knives, and the nip roller configured to receive the waste thermoplastic sheet material being conveyed along a second stream released from the one or more anvil surfaces.
6 . The method of claim 5 , wherein the first stream and the second stream are angled away from one another, an angle between the first stream and the second stream being an obtuse angle.
7 . The method of claim 1 , wherein the gap comprises a distance of approximately five microns.
8 . The method of claim 2 , wherein the thermoplastic material comprises high density polyethylene and calcium carbonate.
9 . The method of claim 8 , wherein the thermoplastic material comprises between about 20% and about 30% calcium carbonate by weight.
10 . The method of claim 1 , wherein the strip of frangibly connected parts comprises a frangible cap strip comprising: a plurality of fastening caps arranged consecutively along the frangible cap strip, the fastening caps being spaced from one another; a plurality of frangible tabs, each of the frangible tabs configured to join adjacent fastening caps and to extend along a first axis extending through a center of each of the fastening caps along the frangible cap strip, each of the frangible tabs comprising: the frangible zone comprising a divot, the divot being closer along the first axis to a first one of a pair of adjacent fastening caps than to a second one of the pair of adjacent fastening caps; a first tab portion formed between the divot and the first one of the pair of adjacent fastening caps; and a second tab portion formed between the divot and the second one of the pair of adjacent fastening caps.
11 . The method of claim 10 , wherein the frangible zone further comprises a depression and a shear line, wherein the divot is disposed at the shear line, and wherein the depression is disposed at the second tab portion.
12 . The method of claim 11 , wherein the depression of each of the frangible tabs extends below a medial plane defined by a bottom side of each of the fastening caps.
13 . The method of claim 11 , wherein the depression of each of the frangible tabs is substantially T-shaped.
14 . The method of claim 10 , wherein the second tab portion is configured to form a hinge configured to increase compression, and prevent inversion of the fastening cap from overshooting or overpressing the fastening cap down onto a working surface.
15 . The method of claim 10 , wherein the frangible zone comprises a thermoplastic material having a molecular alignment, and wherein the molecular alignment is in a general direction of the first axis.
16 . The method of claim 10 , wherein the method does not comprise injection molding.
17 . The method of claim 10 , wherein each of the fastening caps comprises a top side and a bottom side opposing the top side, each of the bottom sides comprising at least one depression, and wherein the at least one depression comprises at least one of a kidney shape and a circular shape.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. patent application Ser. No. 18/613,927 filed Mar. 22, 2024, which claims the benefit of U.S. Provisional Application No. 63/454,239, filed Mar. 23, 2023, each of which is incorporated herein in their entirety by this reference. FIELD Embodiments of the present invention relate to a system and method for manufacturing parts using continuous roll molding. BACKGROUND Parts, such as plastic or metal consumer products, may be made using various manufacturing methods. Injection molding is one method that produces parts by heating material to beyond its melting point and adding molten material into a mold shaped to form the particular part. The material is then cooled to allow for part removal from the mold. Examples of parts that may be formed by manipulating plastic or metal include fasteners for securing materials to a work surface, such as staples having legs. The fasteners may beneficially protect the surface from damage while allowing the nail to secure the material to the surface. Such fasteners may be generally circular caps made from metal or plastic. Each cap may receive the legs of the nail and surround the legs as the nail is engaged with a surface. Cap feeders are powered tools that drive nails through caps to secure a material to a surface. SUMMARY Embodiments provide a method of forming a strip of frangibly connected parts. The method may include providing a thermoplastic material and conveying the thermoplastic material through a continuous roll molder including a first roller and an opposing second roller. The first roller may have a circumference, and further may have a first series of first shapes arranged around the circumference of the first roller. The second mold may have a circumference, and further may have a second series of second shapes arranged around the circumference of the second roller. The rollers may be configured so that the first series of first shapes opposes the second series of second shapes to form the strip of frangibly connected parts comprising a three dimensional shape on both sides of the strip of frangibly connected parts. A first shape of the first roller and a corresponding second shape of the second roller may be configured to form a first part of the strip of frangibly connected parts. At least one of the first shapes and the second shapes may have a projection portion projecting radially from the circumference of the respective first and second roller and is configured for imparting a three-dimensional shape on a surface of one of the parts of the strip of frangibly connected parts. The first shapes further may have knives at least partially surrounding the projection portion and configured to cut the thermoplastic sheet material, and the second shapes further may have anvil surfaces against which the knives of the first mold are configured to cut against. The method may further include one or more channels configured to receive a temperature-controlled fluid of the temperature control system; forming a frangible zone between adjacent parts of the strip of frangibly connected parts utilizing the knives and anvil surfaces; cutting the thermoplastic sheet material into the strip of frangibly connected parts utilizing the knives and anvil surfaces; and separating the strip of frangibly connected parts from a waste thermoplastic sheet material such that the strip of frangibly connected parts and the waste thermoplastic sheet material are separated after release from the continuous roll molder. In some embodiments, providing a thermoplastic sheet material may include conveying a thermoplastic material through a sheet die to form a thermoplastic sheet material, the thermoplastic sheet material comprising a first surface, a second surface, and an intermediate portion disposed between the first surface and the second surface. In some embodiments, the thermoplastic sheet material may include a single layer. In some embodiments, the method may further include between conveying the thermoplastic sheet material through the sheet die to form a thermoplastic sheet material and conveying the thermoplastic sheet material through the continuous roll molder: conveying the thermoplastic sheet material through a calendering system configured to reduce a temperature of the first surface and the second surface when conveying the thermoplastic sheet material through the calendering system. In some embodiments, the continuous roll molder may include a bar and a nip roller, the bar configured to receive the frangibly connected parts being conveyed along a first stream released from the knives, and the nip roller configured to receive the waste thermoplastic sheet material being conveyed along a second stream released from the anvil surfaces. In some embodiments, the first stream and the second stream may be angled away from one another, an angle between the first stream and the second stream being an obtus