Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – Shaping against forming surface
Reexamination Certificate
1994-05-31
2001-04-17
Ortiz, Angela (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
Shaping against forming surface
C264S318000, C264S334000
Reexamination Certificate
active
06217813
ABSTRACT:
BACKGROUND OF THE INVENTION
The present Invention generally pertains to injection molding of elongated articles, such a cable ties, and is particularly directed to methods for reducing the cycle time for injection molding of such elongated articles.
A cable tie is an adjustable strap for bundling together articles such as cables or the like. Cable ties are also known as cable straps, cable clamps, cable clips, bundling ties, bundling straps, bundling clips, bundle ties, bundling belts, wire ties, ring clamps, adjustable clamps, harnessing devices, strap seals, binding straps, and ties. A typical cable tie includes an elongated strap with an adjacent locking head at one end of the strap, a tip at the opposite end of the strap and ratchet teeth on one side of the strap. The locking head defines an opening for allowing the tip end of the strap to be pulled through the opening and thereby form a closed loop around a bundle of articles. The locking head typically further includes a pawl having teeth with surfaces for engaging the ratchet teeth to lock the strap in the locking head after the tip end of the strap has been pulled through said opening. Examples of cable ties are described in U.S. Pat. Nos. 3,739,429, 3,924,299, 3,965,538, 4,473,524 and 4,573,242.
Cable ties are manufactured economically by a cyclic injection molding method, in which molten plastic material is injected into a mold cavity defining the cable tie and then allowed to solidify within the mold cavity. The mold parts defining the mold cavity are then separated and the cable tie is ejected, first from the mold parts and then from the space between the mold parts. A preferred material for cable ties is nylon.
SUMMARY OF THE INVENTION
The present invention provides methods for rapid injection molding of elongated articles, such as cable ties.
In accordance with one aspect of the present invention, a method of injection molding a cable tie having a locking head, and a strap terminating in a tip for passing through said head and ratchet teeth on one side of the strap, wherein the locking head includes a pawl having teeth with surfaces for engaging the ratchet teeth to lock the strap in the locking head after the tip end of the strap has been pulled through the head, includes the steps of (a) forming the cable tie by injecting molten plastic material into a mold cavity defined between a first mold part and a second mold part, wherein the first mold part includes a head region defining a portion of the head of the cable tie and the second mold part includes a tip region defining a portion of the tip of the cable tie; (b) separating the first mold part from the second mold part while retaining said portion of the head of the cable tie in the head region of the first mold part and said portion of the tip of the cable tie in the tip region of the second mold part, to separate the head from the second mold part, to separate the tip from the first mold part, and to separate a major portion of the strap of the cable tie from the first and second mold parts: (c) further separating the first mold part from the second mold part while retaining said portion of the head of the cable tie in the head region of the first mold part to thereby remove said portion of the tip of the cable tie from the second mold part; and (d) ejecting the head of the cable tie from the head region of the first mold part. By retaining a portion of the head in the first mold part and a portion of the tip in the second mold part, while the first and second mold parts are separated from each other, the major portion of the strap is quickly peeled from the first and second mold parts to reduce the overall cycle time.
Additional features and advantages of the present invention are described in relation to the description of the preferred embodiment.
REFERENCES:
patent: 3093865 (1963-06-01), Peters et al.
patent: 3159878 (1964-12-01), Scott, Jr. et al.
patent: 3537676 (1970-11-01), Miller
patent: 3776676 (1973-12-01), Kessler
patent: 3898315 (1975-08-01), Haag
patent: 4076483 (1978-02-01), Smirne
patent: 4238106 (1980-12-01), Willingham
patent: 4354995 (1982-10-01), Wiechard
patent: 4427618 (1984-01-01), Sorensen
patent: 4432127 (1984-02-01), Diazzi
patent: 4666323 (1987-05-01), Kessler
patent: 4776067 (1988-10-01), Sorenson
patent: 4880587 (1989-11-01), Fichlseder et al.
patent: 4902218 (1990-02-01), Leonard
patent: 4944475 (1990-07-01), Ono et al.
patent: 5006288 (1991-04-01), Rhodes, Jr. et al.
patent: 5028225 (1991-07-01), Staheli
patent: 5053179 (1991-10-01), Masu et al.
patent: 1485656 (1970-02-01), None
patent: 1800861 (1970-05-01), None
Sorensen Jens Ole
Sorensen Soren Christian
Callan Edward W.
GB Electrical Inc.
Ortiz Angela
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