Removal of cable tie from mold parts

• US 6,616,884 B1
• Filed: 03/26/2001
• Issued: 09/09/2003
• Est. Priority Date: 03/26/2001
• Status: Expired due to Fees

• Current Assignee: Carol Sorensen
• Original Assignee: Soren Christian Sorensen
• Inventors: Sorensen, Jens Ole, Sorensen, Soren Christian
• Primary Examiner(s): HEITBRINK, JILL LYNNE
• Application Number:
  US09/817,816
• Time in Patent Office: 897 Days
• Field of Search: 264/328.1, 264/318, 264/334, 264/335, 264/336, 425/437, 425/443, 425/556, 425/DIG.58
• US Class Current: 264/318
• CPC Class Codes: B29C 2045/4084 Progressive ejection
• CPC Class Codes: B29C 45/40 Removing or ejecting moulded articles
• CPC Class Codes: B29L 2031/7276 Straps or the like

Abstract

A cable tie having a locking head and a strap terminating in a tip is formed by injecting plastic material into a mold cavity defined by a first mold part that includes a head region defining a portion of the head and a second mold part that includes a tip region defining a portion of the tip. Upon initial separation of the mold parts a portion of the head is retained in the head region of the first mold part and a portion of the tip is retained in the tip region of the second mold part. Upon further separation of the mold parts, the tip is still retained in the tip region of the second mold part and the head is removed from the head region of the first mold part. Subsequently, the tip of the cable tie is ejected from the tip region of the second mold part.

Claims

1. A method of injection molding a cable tie having a locking head, a strap extending from the head and terminating in a tip for passing through an opening in the head, and ratchet teeth on at least 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 opening in the head, the method comprising the steps of

(a) forming the cable tie by injecting molten plastic material into a mold cavity defined by a first mold part combined with 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 still retaining said portion of the tip of the cable tie in the tip region of the second mold part;

(d) removing said portion of the head of the cable tie from the head region of the first mold part; and

(e) subsequent to steps (c) and (d), ejecting the tip of the cable tie from the tip region of the second mold part.

7. A method according to claim 1, 2, 3, 4 or 6, wherein step (a) includes the step of:

(f) injecting said molten plastic material through a gate that is located in the first mold part.

8. A method according to claim 1, 2, 3, 4 or 6, wherein step (a) includes the step of:

(f) injecting said molten plastic material through a gate that is located in the second mold part.

9. A method according to claim 1, 2, 3, 4, 5 or 6, wherein step (a) includes the step of:

(f) injecting said molten plastic material through a gate that is located adjacent the tip region.

10. A method according to claim 1, 2, 3, 4, 5 or 6, wherein step (a) includes the step of:

(f) injecting said molten plastic material through a gate that is located adjacent the head region.

11. A method according to claim 1, 2, 3, 4, 5 or 6, wherein step (b) comprises using an undercut located in the second mold part to retain said portion of the tip of the cable tie in the tip region of the second mold part.

12. A method according to claim 1, 2, 3, 4, 5 or 6, wherein step (d) of claim 2 or 3 or step (e) of claim 1, 4, 5 or 6 comprises using at least one ejector pin to remove the tip of the cable tie from the tip region of the second mold part.

2. A method of injection molding a cable tie having a locking head, a strap extending from the head and terminating in a tip for passing through an opening in the head, and ratchet teeth on at least 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 opening in the head, the method comprising the steps of

(a) forming the cable tie by injecting molten plastic material into a mold cavity defined by a first mold part combined with 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) subsequent to step (b) while still retaining said portion of the tip of the cable tie in the tip region of the second mold part, ejecting said portion of the head of the cable tie from the head region of the first mold part; and

(d) subsequent to step (c), ejecting the tip of the cable tie from the tip region of the second mold part.

13. A method according to claim 2, wherein step (c) comprises using at least one ejector pin to eject said portion of the head of the cable tie.

3. A method of injection molding a cable tie having a locking head, a strap extending from the head and terminating in a tip for passing through an opening in the head, and ratchet teeth on at least 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 opening in the head, the method comprising the steps of

(a) forming the cable tie by injecting molten plastic material into a mold cavity defined by a first mold part combined with 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 still retaining said portion of the tip of the cable tie in the tip region of the second mold part to thereby remove said portion of the head of the cable tie from the head region of the first mold part; and

(d) subsequent to step (c), ejecting the tip of the cable tie from the tip region of the second mold part.

4. A method of injection molding a cable tie having a locking head, a strap extending from the head and terminating in a tip for passing through an opening in the head, and ratchet teeth on at least 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 opening in the head, the method comprising the steps of

(a) forming the cable tie by injecting molten plastic material into a mold cavity defined by a first mold part combined with 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 still retaining said portion of the tip of the cable tie in the tip region of the second mold part;

(d) removing said portion of the head of the cable tie from the head region of the first mold part; and

(e) subsequent to steps (c) and (d), ejecting the tip of the cable tie from the tip region of the second mold part;

wherein step (a) comprises injecting said plastic material through a gate located in either the first mold part or the second mold part; and

wherein either step (d) or step (e) comprises using at least one ejector pin located in the one of the first or second mold parts in which the gate is not located.

5. A method of injection molding a cable tie having a locking head, a strap extending from the head and terminating in a tip for passing through an opening in the head, and ratchet teeth on at least 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 opening in the head, the method comprising the steps of

(a) forming the cable tie by injecting molten plastic material into a mold cavity defined by a first mold part combined with 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 still retaining said portion of the tip of the cable tie in the tip region of the second mold part;

(d) removing said portion of the head of the cable tie from the head region of the first mold part; and

(e) subsequent to steps (c) and (d), ejecting the tip of the cable tie from the tip region of the second mold part;

wherein step (a) comprises injecting said plastic material through a gate located in the first mold part; and

wherein step (b) or step (c) comprises using an undercut located in the second mold part to retain said portion of the tip of the cable tie in the tip region of the second mold part.

6. A method of injection molding a cable tie having a locking head, a strap extending from the head and terminating in a tip for passing through an opening in the head, and ratchet teeth on at least 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 opening in the head, the method comprising the steps of

(a) forming the cable tie by injecting molten plastic material into a mold cavity defined by a first mold part combined with a second mold part, wherein the first mold part includes a head region defining a portion of the head of the cable tie, the second mold part includes a tip region defining a portion of the tip of the cable tie, and said mold parts further define a strap region for forming the portion of the strap that extends between the head and 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 still retaining said portion of the tip of the cable tie in the tip region of the second mold part;

(d) removing said portion of the head of the cable tie from the head region of the first mold part; and

(e) subsequent to steps (c) and (d), ejecting the tip of the cable tie from the tip region of the second mold part;

wherein step (a) comprises injecting said plastic material through a gate located adjacent either the tip region or the head region; and

wherein step (b) comprises using an undercut located in the strap region of the one of the first or second mold parts in which the tip region or the head region that is adjacent the gate is not located to pull at least a portion of the strap from the portion of the strap region defined by the one of the first or second mold parts in which the tip region or the head region that is adjacent the gate is located, as said mold parts are separating.