SELF-LOCKING HEAT SHRINKABLE INSULATING SLEEVE

• US 3,678,174 A
• Filed: 01/15/1971
• Issued: 07/18/1972
• Est. Priority Date: 01/15/1971
• Status: Expired due to Term

• Current Assignee: Harry E. Ganzhorn
• Original Assignee: Harry E. Ganzhorn
• Inventors: Ganzhorn, Harry E.
• Primary Examiner(s): Clay, Darrell L.
• Application Number:
  US05/106,848
• Time in Patent Office: 550 Days
• Field of Search: 174/84R,84C,90,94R,93,DIG.8 339/275R 287/78 228/56 29/628
• US Class Current: 174/84.00R
• CPC Class Codes: B29C 61/0608 characterised by the configuration or structure of the preforms
• CPC Class Codes: H01R 4/22 End caps, i.e. of insulating or conductive material for covering or maintaining connections between wires entering the cap from the same end
• CPC Class Codes: H01R 4/723 Making a soldered electrical connection simultaneously with the heat shrinking
• CPC Class Codes: H02G 15/1806 Heat shrinkable sleeves insulation of electrical connections using a heat shrinking insulating sleeve H01R4/72
• CPC Class Codes: Y10S 174/08 Shrinkable tubes

Abstract

An insulation sleeve of the type used to provide electrical insulation around an electrical connection is disclosed. This sleeve has at least one end which has a re-entrant configuration projecting back into the interior of the sleeve such that at least a portion of the re-entrant is held away from the inside surface of the sleeve. This provides a self-locking feature when an object of an appropriate size is inserted through this end. The sleeve may then be heat shrunk around the connection or can serve as an insulator without further recovery. The sleeve may also be provided with a solder insert. A process for fabricating such a sleeve is also disclosed. Such sleeves are particularly useful for insulating an electrical connection made by a ferrule which has been crimped over the stripped ends of insulated conductors.

Claims

1. A sleeve formed of heat shrinkable material comprising:

a hollow heat shrinkable polymeric member having at least one open end and having an integral re-entrant portion projecting back into the interior of the sleeve at said open end at least a portion of said re-entrant portion being displaced from the inner surface of said hollow member.

2. The sleeve of claim 1 wherein said hollow member has two open ends.

3. The sleeve of claim 1 wherein said re-entrant means is generally pyramidal in shape and has a generally rectangular opening therein.

4. The sleeve of claim 3 wherein the width of said rectangular opening is at least 2 times its height.

5. The sleeve of claim 1 wherein said re-entrant means is generally conical in shape and has a generally circular opening therein.

6. The sleeve of claim 1 wherein said hollow member is cylindrical.

7. The sleeve of claim 1 wherein said hollow member is fabricated from a heat recoverable irradiated polyolefin.

8. The sleeve of claim 1, wherein a fusible insert is positioned within said hollow member.

9. The sleeve of claim 8 wherein said fusible insert comprises solder.

10. The sleeve of claim 6 wherein one end of said cylindrical body is closed.

11. The sleeve of claim 1 wherein said hollow member has a plurality of open ends and more than one of said open ends is provided with the defined re-entrant means.

12. The sleeve of claim 1 wherein said re-entrant portion projects back into the interior of said sleeve a distance of between one-third and two times the outside diameter of said hollow member.

13. The sleeve of claim 1 wherein said re-eNtrant portion is displaced from said inner surface of said hollow member a distance at least equal to the wall thickness of said cylindrical member.

14. A self-locking insulation sleeve for electrically insulating a junction between the stripped ends of at least two insulated conductors comprising:

a hollow heat shrinkable polymeric member having at least one open end and having an integral re-entrant portion projecting back into the interior of the sleeve at said open end at least a portion of said re-entrant portion being displaced from the inner surface of said hollow member, said re-entrant portion being shaped so that it is radially displaced by the insertion of said junction.

15. The sleeve of claim 14 wherein said hollow member has two open ends provided with the defined re-entrant means.

16. The sleeve of claim 14 wherein said hollow member has one open end.

17. The sleeve of claim 14 wherein a fusible insert is positioned within said hallow member.

18. A process for making a self-locking insulation sleeve from a generally cylindrical hollow member fabricated from a heat recoverable thermoplastic resin, comprising:

holding an end of said member against a heated surface having a temperature at least equal to the heat recovery temperature of said resin for a time sufficient to raise the temperature of the end of the member to said heat recovery temperature and to form said end inwardly;

separating the member from contact with said heated surface;

inserting a shaped mandrel into said heated end and forming said heated end into a shaped, re-entrant configuration;

cooling said heated end, and removing said mandrel.