GB2192101A

GB2192101A - Insulation piercing crimp terminal

Info

Publication number: GB2192101A
Application number: GB08615940A
Authority: GB
Inventors: Patrick Shui-Chung Wang
Original assignee: Johnson Electric Industrial Manufactory Ltd
Current assignee: Johnson Electric Industrial Manufactory Ltd
Priority date: 1986-06-30
Filing date: 1986-06-30
Publication date: 1987-12-31
Also published as: GB8615940D0

Abstract

A terminal for enamel coated wire comprises a crimping portion 14 having grooves 9 formed in its base. Each groove 9 has cutting edges 10 which penetrate the wire coating as the terminal is crimped on the wire. Two crossing grooves may be provided, and a bulge 20 may be formed in the material below the grooves to cause the internal corners 19 formed by the grooves to point upwardly. <IMAGE>

Description

SPECIFICATION Terminal The present invention relates to a terminal, and more particularly to a terminal which may be crimped onto enamel coated wire, making electrical connection with the wire without the need to strip the wire. The terminal finds particular application for connection to the wiring of stator field windings in electric motors.

Typically, stator field windings, and other motor windings, are wound with copper wire which has a high temperature enamel coating which is non-conductive, to avoid shorting between adjacent coil turns. When crimping a terminal onto the wire, it is necessary to strip the coating off the wire first, so that the terminal is in electrical contact with the bare copper.

The present invention aims to obviate the step of stripping off the wire coating.

According to a first aspect of the invention there is provided a terminal for a coated wire, the terminal having a crimping portion to be crimped on the wire to make electrical connection therewith, wherein the crimping portion is provided with a formation which will penetrate the wire coating as the terminal is crimped on the wire.

Preferably, the crimping portion has a Ushaped cross-section prior to crimping, and an edge is provided in the base of the U, the edge cutting into the wire coating as the wire is urged into the base of the U during crimping.

Preferably the formation is formed by stamping or cutting the material of the crimping portion. Preferably the formation comprises a cut or incision made in the base of the U to form an upwardly projecting edge.

Preferably a cross-shaped cut or incision is made. Preferably the cut penetrates the material of the crimping portion at the centre of the cross. Very preferably a cut extends in a longitudinal direction of the crimping portion.

Preferably the material of the crimping portion in the region of the cut or incision is defomed inwardly from below to raise the edges of the cut.

Another aspect of the invention provides a method of electrically connecting a terminal to a coated wire, comprising forming a blank for the terminal, the blank having a crimping portion, stamping a V-shaped groove in the crimping portion, folding the crimping portion, to form a U shape, placing a coated wire in the base of the U shape and crimping the terminal on the wire coating.

Preferably, the groove extends in the direction of a fold line of the crimping portion.

Preferably two grooves are formed, the second groove meeting or crossing the first groove at an angle, preferably about 90". The groove preferably extends to about 75" of the depth of the material of the crimping portion.

Preferably material below the groove is bulged upwardly with respect to the groove to raise the edges of the groove, it is particuiarly preferably to form the bulge at the cross-over point of two grooves. The bulge may be formed at the same time as or before or after the grooves.

Other preferred features and advantages of the invntion will be apparent from the following detailed description and the accompanying claims.

The invention will be further described by way of example with reference to the accompanying drawings, in which: Figure 1 is a plan view of a blank for a terminal according to the invention; Figure 2 is an enlarged cross-section along the line ll-ll of Fig. 1; Figure 3 is an underneath view of the terminal of Fig. 1 after folding; Figure 4 is a plan view of the terminal of Fig. 3; Figure 5 is a cross-section along the line V-V of Fig. 4; and Figure 6 is an enlarged end view on arrow A of Fig. 5.

Referring to Fig. 1, a blank 1 for a terminal according to the invention is cut or stamped from sheet metal, and comprises a crimping part 2 and a connector part 3. Connector part 3 has two wing portions 4, 5 which are folded over to form a female connector portion 13 (Fig. 6). Tongues 6, 7 are stamped on the connector part 3 of the blank for securing the formed connector portion 13 to a male terminal (not shown), as is known in the art.

A neck 8 joins the connector part 3 to crimping part 2. Crimping part 2 has a pair of cross-shaped, V-section groove formations 9 indicated in outline in Fig. 1, stamped in its upper surface. Referring to the enlarged crosssection of Fig. 2, walls 11 of the V-shaped grooves subtend an angle of about 60 and the depth of the grooves is about 75 percent of the thickness of the material.

An upstanding edge or pointed lip 10 is formed at the top of each groove wall 11.

The material below the cross-over of the grooves is bulged upwardly, see Figs. 3 and 5, to raise corners 19 formed at the crossover of the grooves. This may be done by a stamping process, preferably when forming the grooves.

After forming the tongues 6, 7 and formations 9, the blank 1 is folded to form a terminal 12, as seen in Figs. 3 to 6.

The folding operation is performed in a manner generally known in the terminal production art. Wing portions 4, 5 are folded over to form female connector 13 and neck 8 is pressed downwardly to move the crimping part 2 below the plane of the connector and is dished 15 in transverse cross-section.

The crimping part 2 is folded into a U shape (Fig. 6) to form a crimping portion 14.

Side walls 17 of the crimping portion 14 are chamfered at their edges 16 and a cutaway portion 18 is provided to facilitate crimping.

During the folding of the crimping part 2 the V-shaped grooves 9 are distorted. The formations and function of these grooves will now be described in more detail.

Referring to Fig. 1, two groove formations 9 having a cross-shape when viewed in plan are stamped in the crimping part 2. Each formation comprises two grooves which cross each other and are formed with a sharp edge, in the form of a lip 10 in the present embodiment. One leg of each cross-shape extends in the longitudinal direction of the crimping part 2. A bulge 20 is formed in the material beneath the grooves, which cause the internal corners 19 of the cross-shaped formations 9 to project upwardly as sharp points.

Crimping part 2 is folded about the longitudinal direction. The grooves extending transversely across the bottom of the Ushaped crimping portion are dimensioned to extend part way up the sidewalls 17, see Figs. 4, 5 and 6. As the crimping part 2 is folded the internal corners 19 of the cross shape which are opposite one another across the fold line move together, i.e. there is a tendency to close the longitudinal grooves.

During a crimping operation, the coated wire is laid in the bottom of the U-shaped portion and the chamfered ends of the walls 17 are turned over and pressed down towards the base of the U during crimping.

This flattens the base of the U and so moves the opposed corners 19 apart, causing them to tear into the insulation and make electrical contact with the revealed wire. The crimping operation may cause the material in the bulged part, at the base of the V-shape groove, to split. This is not disadvantageous since the grooves do not extend along the complete length of the connector portion.

It will be appreciated that the invention is applicable to other types of terminals or connectors where a crimping operation is used.

Various modifications will be apparent tothose in art and it is desired to include all such modifications as fall within the scope of the accompanying claims.

Claims

1. A terminal for a coated wire, the terminal having a crimping portion to be crimped on the wire to make electrical connection therewith, wherein the crimping portion is provided with a formation which will penetrate the wire coating as the terminal is crimped on the wire.

2. A terminal as claimed in claim 1, wherein the crimping portion has a U-shaped cross-section prior to crimping, and the formation comprises an edge provided in the base of the U to cut into the wire coating during crimping.

3. A terminal as claimed in claim 1 or 2, wherein the formation is formed by cutting or stamping the material of the crimping portion.

4. A terminal as claimed in claim 1, 2 or 3, wherein the formation comprises a V-shape groove.

5. A terminal as claimed in claim 4, wherein the groove has a pointed lip which extends above the surface of the crimping portion.

6. A terminal as claimed in claim 4 or 5, wherein the groove extends along a fold line of the criimping portion.

7. A terminal as claimed in claim 4 5 or 6, wherein the or a groove extends to about 75% of the depth of the material of the crimping portion.

8. A terminal as claimed in anyone of claims 4 to 7, wherein two grooves are provided, the grooves crossing one another.

9. A terminal as claimed in claim 7 or 8, wherein a bulge is provided in the material of the crimping portion below the region where the grooves cross over.

10. A method of electrically connecting a terminal to a coated wire, substantially as hereinbefore described with reference to the accompanying drawings.

10. A terminal as claimed in any one of claims 1 to 8, wherein two formations are provided.

11. A terminal for a coated wire, substantially as hereinbefore described with reference to the accompanying drawings.

12. A method of electrically connecting a terminal to a coated wire, comprising forming a blank for the terminal, the blank having a crimping part and a V-shaped groove in the crimping part, folding the crimping part to form a U-shaped, placing a coated wire in the base of the U and crimping the terminal on the wire, whereby an edge portion of the Vshaped groove penetrates the wire coating.

13. A method as claimed in claim 11, wherein an edge of the groove is proud of the surface of the crimping part.

14. A method as claimed in claim 12, wherein the groove extends in the direction of a fold line of the crimping part.

15. A method as claimed in claims 11, 12 or 13, wherein the groove extends to about 75% of the depth of the material of the crimping part.

16. A method as claimed in any one of claims 11 to 14, wherein a second groove is formed crossing the first groove.

17. A method as claimed in claim 16, wherein an upwardly directed bulge is formed in the material of the crimping portion below the cross-over region of the grooves.

18. A method of electrically connecting a terminal to a coated wire, substantially as hereinbefore described with reference to the accompanying drawings.

Amendments to the claims have been filed, and have the following effect: Claims 1 to 18 above have been deleted or textually amended.

New or textually amended claims have been filed as follows: CLAIMS

1. A terminal for a coated wire, the terminal having a crimping portion to be crimped on the wire to make electrical connection therewith, the crimping portion being of Ushaped cross-section prior to crimping and being provided in its base with a formation which will penetrate the coating as the terminal is crimped to the wire, the formation comprising two V-shaped grooves crossing one another, the internal corners of the crossshaped formation projecting upwardly as sharp points.

2. A terminal as claimed in claim 1, wherein the formation is formed by cutting or stamping the material of the crimping portion.

3. A terminal as claimed in claim 1 or 2, wherein one of the grooves extends along a fold line of the crimping portion.

4. A terminal as claimed in claim 1, 2 or 3, wherein the grooves extend to about 75% of the depth of the material of the crimping portion.

5. A terminal as claimed in anyone of the preceding claims, wherein two formations are provided.

6. A terminal for a coated wire, substantially as hereinbefore described with reference to the accompanying drawings.

7. A method of electrically connecting a terminal to a coated wire, comprising forming a blank for the terminal the blank having a crimping portion and a formation comprising two V-shaped grooves crossing one another in the crimping portion, forming an upwardly directed bulge in the material of the crimping portion below the cross-over region of the grooves so that the internal corners of the cross-shaped formation project upwardly as sharp points, folding the crimping portion to form a U-shape, placing a coated wire in the base of the U and crimping the terminal on the wire, whereby the internal corners of the cross-shaped formation penetrate the wire coating.

8. A method as claimed in claim 7, wherein one of the grooves extends in the direction of a fold line of the crimping portion.

9. A method as claimed in claim 7 or claim 8, wherein the grooves extend to about 75% of the depth of the material of the crimping portion.