Key assembly for vehicle ignition locks

• US 6,948,344 B2
• Filed: 07/23/2002
• Issued: 09/27/2005
• Est. Priority Date: 08/26/1993
• Status: Expired due to Fees

• Current Assignee: Strattec Security Corporation
• Original Assignee: Strattec Security Corporation
• Inventors: Janssen, David C
• Primary Examiner(s): Gall, Lloyd A.
• Application Number:
  US10/201,633
• Publication Number:
  US 20030051520A1
• Time in Patent Office: 1,162 Days
• Field of Search: 704/08, 702781-2787, 703/95, 704/13, 702/76, 702/77, 702/791, 70280-283, 702/831
• US Class Current: 70/278.3
• CPC Class Codes: E05B 19/04 Construction of the bow or head of the key; Attaching the bow to the shank
• CPC Class Codes: G06K 19/04 characterised by the shape
• CPC Class Codes: G06K 19/048 the record carrier being shaped as a key
• CPC Class Codes: G07C 9/00944 Details of construction or manufacture
• CPC Class Codes: Y10T 70/7079 Key rotated [e.g., Eurocylinder]
• CPC Class Codes: Y10T 70/7802 Multi-part structures
• CPC Class Codes: Y10T 70/7876 Bow or head
• CPC Class Codes: Y10T 70/7904 Magnetic features

Abstract

A method of decreasing resonant frequency shifting of an electrical circuit mounted on a vehicle key includes providing a frame in an opening in the head portion of a vehicle key and locating the transponder in the frame. The frame comprises substantially rigid non-metallic material, and the frame includes a support structure for supporting the transponder while decreasing forces produced on the transponder by thermal expansion and contraction of the head portion of the key, thereby decreasing shift in the resonance of the electrical circuit of the transponder. The frame, the transponder and the head portion of the key are overmolded providing an outer covering that encloses and protects the transponder.

Claims

1. A method of decreasing resonant frequency shifting of an electrical circuit of a transponder mounted on a substantially rigid vehicle key including a blade portion and a head portion, comprising the steps of:

inserting the key and the transponder into a mold;

injecting a substantially rigid, non-metallic material into the mold while the key and transponder are in the mold to form an undermold of said vehicle key, the undermold comprising a plurality of voids between the substantially rigid, non-metallic material and the transponder;

supporting the transponder in the undermold;

reducing forces produced on the electrical circuit by thermal expansion and contraction of at least one portion of the key by the plurality of voids between the substantially rigid, non-metallic material and the transponder, thereby decreasing resonant frequency shifting of said electrical circuit of said transponder; and

overmolding said undermold, the transponder, and said one portion of said key with an overmold material.

2. The method as defined in claim 1, wherein said overmolding step includes forming overmold material over at least the transponder and the head portion of said key for retaining said transponder on said key.

3. The method as defined in claim 1, further including forming said undermold to include a plurality of tabs in contact with the transponder.

4. The method as defined in claim 1, including forming said undermold to include thin support portions in contact with the transponder, wherein the thickness of the thin support portions is less than the thickness of the transponder.

5. A method of mounting a transponder on a substantially rigid vehicle key including a blade portion and a head portion, comprising the steps of:

molding a non-metallic frame including a mounting portion for mounting the transponder on said head portion of said key, said frame including a support structure for supporting the transponder primarily at sides of the transponder while allowing a majority of planar surface areas of the transponder to be located adjacent mold surfaces to reduce thermal shock due to contact with liquid molding material for said frame; and

overmolding at least a portion of said frame and the transponder with an overmold material.

6. The method as defined in claim 5, wherein the step of overmolding includes molding said overmolding material in contact with the transponder for retaining said transponder on said key.

7. The method as defined in claim 5, including forming said support structure to include a plurality of tabs in contact with the transponder.

8. The method as defined in claim 5, including forming said support structure to include thin support portions in contact with the transponder, wherein the thickness of the thin support portions is less than the thickness of the transponder.

9. The method as defined in claim 5, including forming said support structure to include at least one thin support portion having a first side contacting the transponder and having a second side contacting said overmolding material.