Method and device for producing a decorative ornamental part with symbol in relief

• US 7,641,843 B2
• Filed: 07/25/2005
• Issued: 01/05/2010
• Est. Priority Date: 07/26/2004
• Status: Active Grant

• Current Assignee: Faurecia Angell-Demmel GmbH (Forvia SE)
• Original Assignee: Angell-Demmel GmbH
• Inventors: Taemmerich, Rolf, Bruennel, Elmar
• Primary Examiner(s): Del Sole; Joseph S.
• Assistant Examiner(s): Smith; Jeremiah
• Application Number:
  US11/188,008
• Publication Number:
  US 20060019065A1
• Time in Patent Office: 1,625 Days
• Field of Search: 264/328.7
• US Class Current: 264/328.7
• CPC Class Codes: B29C 2045/14147 using pins or needles penetrating through the insert
• CPC Class Codes: B29C 2045/14188 trimming the article in the mould
• CPC Class Codes: B29C 45/14073 using means being retractable during injection
• CPC Class Codes: B29C 45/14221 by tools, e.g. cutting means
• CPC Class Codes: B29C 45/14688 Coating articles provided with a decoration
• CPC Class Codes: B29K 2705/00 Use of metals, their alloys or their compounds, for preformed parts, e.g. for inserts
• CPC Class Codes: B29L 2031/466 Keypads, keytops
• CPC Class Codes: H01H 9/18 Distinguishing marks on switches, e.g. for indicating switch location in the dark; Adaptation of switches to receive distinguishing marks
• CPC Class Codes: Y10T 428/24322 Composite web or sheet

Abstract

The invention describes a method for producing a decorative ornamental part, eg a control key, having a symbol in relief that is defined by a clearance gap free as far as possible of webs and connections in the frame of the control key, wherein the decorative ornamental part is back-injected with a plastic melt by the plastic injection moulding process. In order to obtain a surface on the visible side of the inner part which is free of traces of clamping and retaining it is proposed: that the production method consists of a cutting operation to produce the clearance gap, that the stamping punch carrying out the cutting operation remains as a place-holder in the cut contour of the clearance gap during the injection operation, and that the subsequent injection operation producing a bond ensures the exact connection of the contour of the cut free inner part to the frame of the ornamental part.

Claims

1. Method for producing a decorative ornamental part, having a symbol (32) in relief that is defined by a clearance gap (34) free as far as possible of webs and connections in a frame (31) of a control key (30), wherein the decorative ornamental part is back-injected with a plastic melt (29) by a plastic injection moulding process, comprising:

a cutting operation to produce the clearance gap (34) within the frame (31),

a stamping punch (16) carrying out a cutting operation remains within the frame (31) as a place-holder in the clearance gap (34) during the injection moulding, and

the injection moulding is carried out to produce a bond enabling the exact connection of the cut free inner part (33) to the frame (31) of the ornamental part,

wherein during said injecting moulding, through the degree of filing of the mould cavity (25) or control of holding pressure of the plastic melt (29), the degree of filing of the clearance gap (34) is over filled to a distinctly palpable degree;

characterised in that in a first work step the decorative ornamental part to be back-injected is punched and optionally formed in a mould (1, 20) from a visible side (13) and in doing so punching waste (24) is pushed into an upper half (1) of the mould,

that in a second work step the stamping punch (16) is locked in an extended position passing through the frame (31) and a mould lower part with an inner part fixed by the stamping punch is moved under the upper half of the mould,

that in a third work step a plastic melt (29) is injected into the mould cavity (25) and the cut free inner part (33) is connected to the reverse side of the frame (31) by the plastic melt (29), and

that in a fourth work step after the mould cavity (25) has been filled with plastic melt (29) the stamping punch (16) is unlocked, pulled back to a defined extent and a space liberated comprising the clearance gap (34) is likewise filled with plastic melt (29).

2. Method according to claim 1, characterised in that a mould lower part (20) is used in common for said cutting and said injection moulding.

3. Method according to claim 1, characterised in that an at least partially translucent plastic is used for the plastic melt (29).

4. The method of claim 1, wherein the stamping punch (16) projects into the frame (31) from a female part (22) of an injection mould in which the injection moulding is carried out.

5. A method for producing a control key (30) having a decorative ornamental part with a symbol in relief, where the production method comprises a cutting operation to produce a clearance gap (34) and the decorative ornamental part is back-injected with a plastic melt (29) by a plastic injection moulding process, wherein

the symbol in relief (32) is defined by a clearance gap (34) free of webs and connections in a frame or body (31) of the control key (30);

a stamping punch (16) carrying out the cutting operation remains as a place-holder in the clearance gap (34) during the injection moulding process in an injection mould;

in a first work step, the decorative ornamental part to be back-injected by plastic injection moulding is punched and optionally deformed from a decorated visible side (13) in a first tool (1, 20), whereby punching waste (24) is pushed into an upper half of the first tool (1);

in a second work step, a stamping punch (16) is maintained in an extended cutting position passing through the frame or body (31), and a mould lower part with the frame or body (31) fixed by the stamping punch is moved under an upper part of the injection mould;

in a third work step, a plastic melt (29) is injected into a mould cavity (25) and the symbol in relief (32) is connected with the frame or body (31) by plastic melt (29); and

in a fourth work step, after the mould cavity (25) has been filled with plastic melt (29), the stamping punch (16) is retracted a defined extent and space liberated by the stamping punch comprising the clearance gap (34) is likewise filled with plastic melt (29),

wherein during said injecting moulding, through the degree of filing of the mold cavity (25) or the control of the holding pressure of the plastic melt (29), the degree of filing of the clearance gap (34) is over filled to a distinctly palpable degree.

6. A method in accordance with claim 5, wherein, prior to or at the same time of the cutting operation, forming of a blank (9), forming a precursor of the decorative ornamental part takes place.

7. A method in accordance with claim 5, wherein the mould lower part (20) is used in common for the cutting and injection moulding.

8. A method in accordance with claim 5, wherein at least partially translucent plastic is used for the plastic melt (29).