GB2130024A

GB2130024A - A transformer bobbin and method of producing the transformer bobbin

Info

Publication number: GB2130024A
Application number: GB08231823A
Authority: GB
Inventors: Terence Norman Turnber; John Edward Gard
Original assignee: Plessey Co Ltd
Current assignee: Plessey Co Ltd
Priority date: 1982-11-08
Filing date: 1982-11-08
Publication date: 1984-05-23
Also published as: GB2130024B

Abstract

A transformer bobbin (2) having at least one self-locking terminal pin (4), the terminal pin (4) being self-locking by being bent through substantially 90 DEG in two different planes which are at substantially 90 DEG to each other. A sequence of operations in which a bobbin receives the end of wires for subsequent in situ machining into the required form is disclosed. Bending operations lock the terminal to the bobbin. <IMAGE>

Description

SPECIFICATION A transformer bobbin and method of producing the transformer bobbin This invention relates to a transformer bobbin and to a method of producing the transformer bobbin.

Transformer bobbins are well known and difficulty often arises in providing the transformer bobbins with terminal pins. Often relatively complex and time consuming operations are required.

It is an aim of the present invention to provide as transformer bobbin having an easily fitted terminal pin.

Accordingly, this invention provides a transformer bobbin having at least one selflocking terminal pin, the terminal pin being selflocking by being bent through substantially 900 in two different planes which are at substantially 900 to each other.

Preferably, the transformer bobbin is provided with four of the self-locking terminal pins.

The or each terminal pin will usually be made from electro solder coated copper wire.

The transformer bobbin may be one comprising a moulded bobbin body formed of an electrically insulating material, the said at least one selflocking pin being mounted on the moulded bobbin body, a coil wound around a central hollow core part of the moulded bobbin body, and soft iron laminations supported by the moulded bobbin body.

The coil may be wrapped in insulating tape. The soft iron laminations may be E-shaped laminations. The coil and the laminations may be coated in a resin or varnish.

This invention also provides a method of producing a transformer bobbin having at least one terminal pin, which method comprises feeding a length of wire from a roll through an aperture in a moulded bobbin body such that the wire rests on a forming blade which itself rests in a slot in the moulded bobbin body, rotating the forming blade through 900 to bend the wire in a first plane through 900, cutting the wire to form the terminal pin, and bending the cut end of the wire in two substantially 450 stages so that the cut end of the wire is bent through substantially 900 in a second plane which is at substantially 900 to the first plane.

Usually, the cut wire will be slightly displaced during the cutting step, and, in this case, the cut wire will preferably be repositioned to its former position before being bent in the two 450 bending stages.

Preferably, the method of the invention is such that the transformer bobbin is formed with four terminal pins, the terminal pins being formed in pairs on opposite sides of the transformer bobbin.

An embodiment of both the transformer bobbin and the method of producing the transformer bobbin will now be described solely by way of example and with reference to the accompanying drawings which have been given in tabular form to illustrate the formation of a transformer bobbin having four self-locking terminal pins, the four self-locking terminal pins being produced in twelve separate stages as illustrated.

In the drawings, each of the separate stages is illustrated as Nos. 1 to 12 in the left hand column.

In the middle column, there is described each method stage appropriate to the stage number illustrated in the left hand column. In the right hand column, the appearance of the bobbin at each stage is illustrated. At each stage, the bobbin is illustrated twice, the upper diagram being a top plan view of the transformer bobbin and the lower diagram being a side view of the transformer bobbin.

Referring to the drawings, the precise stages will not be described in detail because the drawings are self-explanatory. In the diagram given for stage 12, it will be seen that there is illustrated a transformer bobbin 2 having four selflocking terminal pins 4. Each terminal pin 4 is self locking because it has been bent through substantially 900 in two different planes which are at substantially 900 to each other. The first bend is that shown by the legs 6, 8. Each leg 8 passes through a hole in a moulded bobbin body 10. The moulded bobbin body 10 comprises a central hollow core part 12 supporting a lower flange 14 and an upper flange 1 6. On the upper flange 16 three raised portions 18, 20, 22 are formed as shown. The portion 1 8 extends along the entire left hand side of the transformer bobbin 2 whilst the portions 20, 22 are just corner portions.

The plan view in the diagram given for stage 12 illustrates the second bend through 900. The leg 8 forms part of the second bend and the other leg of the second bend is 24. The leg 24 is bent at right angles to the leg 8 in two stages, the first of these stages being illustrated at stage 10 and the second of these stages being illustrated at stage 11.

After the cutting stages 4 and 8, it will be noticed that the cut wire gets pushed downwards slightly. This is corrected by repositioning the cut wire as illustrated at stage 9.

The finished bobbin illustrated in Figure 12 is provided with the terminal pins 4 in a particularly efficient manner and one which lends itself to mass production.

It is to be appreciated that the embodiment of the invention described above has been given by way of example only and that modifications may be effected. Thus, for example, the shape of the forming blade 26 (which locates in a top slot 28 in the moulded bobbin body 10) could be thicker and/or shorter than is shown. The precise apparatus shown for cutting and bending the terminal pins has been illustrated diagrammatically and it will be appreciated that such apparatus can be operated electrically, pneumatically or hydraulically.

1. A transformer bobbin having at least one self-locking terminal pin, the terminal pin being

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A transformer bobbin and method of producing the transformer bobbin This invention relates to a transformer bobbin and to a method of producing the transformer bobbin. Transformer bobbins are well known and difficulty often arises in providing the transformer bobbins with terminal pins. Often relatively complex and time consuming operations are required. It is an aim of the present invention to provide as transformer bobbin having an easily fitted terminal pin. Accordingly, this invention provides a transformer bobbin having at least one selflocking terminal pin, the terminal pin being selflocking by being bent through substantially 900 in two different planes which are at substantially 900 to each other. Preferably, the transformer bobbin is provided with four of the self-locking terminal pins. The or each terminal pin will usually be made from electro solder coated copper wire. The transformer bobbin may be one comprising a moulded bobbin body formed of an electrically insulating material, the said at least one selflocking pin being mounted on the moulded bobbin body, a coil wound around a central hollow core part of the moulded bobbin body, and soft iron laminations supported by the moulded bobbin body. The coil may be wrapped in insulating tape. The soft iron laminations may be E-shaped laminations. The coil and the laminations may be coated in a resin or varnish. This invention also provides a method of producing a transformer bobbin having at least one terminal pin, which method comprises feeding a length of wire from a roll through an aperture in a moulded bobbin body such that the wire rests on a forming blade which itself rests in a slot in the moulded bobbin body, rotating the forming blade through 900 to bend the wire in a first plane through 900, cutting the wire to form the terminal pin, and bending the cut end of the wire in two substantially 450 stages so that the cut end of the wire is bent through substantially 900 in a second plane which is at substantially 900 to the first plane. Usually, the cut wire will be slightly displaced during the cutting step, and, in this case, the cut wire will preferably be repositioned to its former position before being bent in the two 450 bending stages. Preferably, the method of the invention is such that the transformer bobbin is formed with four terminal pins, the terminal pins being formed in pairs on opposite sides of the transformer bobbin. An embodiment of both the transformer bobbin and the method of producing the transformer bobbin will now be described solely by way of example and with reference to the accompanying drawings which have been given in tabular form to illustrate the formation of a transformer bobbin having four self-locking terminal pins, the four self-locking terminal pins being produced in twelve separate stages as illustrated. In the drawings, each of the separate stages is illustrated as Nos. 1 to 12 in the left hand column. In the middle column, there is described each method stage appropriate to the stage number illustrated in the left hand column. In the right hand column, the appearance of the bobbin at each stage is illustrated. At each stage, the bobbin is illustrated twice, the upper diagram being a top plan view of the transformer bobbin and the lower diagram being a side view of the transformer bobbin. Referring to the drawings, the precise stages will not be described in detail because the drawings are self-explanatory. In the diagram given for stage 12, it will be seen that there is illustrated a transformer bobbin 2 having four selflocking terminal pins 4. Each terminal pin 4 is self locking because it has been bent through substantially 900 in two different planes which are at substantially 900 to each other. The first bend is that shown by the legs 6, 8. Each leg 8 passes through a hole in a moulded bobbin body 10. The moulded bobbin body 10 comprises a central hollow core part 12 supporting a lower flange 14 and an upper flange 1 6. On the upper flange 16 three raised portions 18, 20, 22 are formed as shown. The portion 1 8 extends along the entire left hand side of the transformer bobbin 2 whilst the portions 20, 22 are just corner portions. The plan view in the diagram given for stage 12 illustrates the second bend through 900. The leg 8 forms part of the second bend and the other leg of the second bend is 24. The leg 24 is bent at right angles to the leg 8 in two stages, the first of these stages being illustrated at stage 10 and the second of these stages being illustrated at stage 11. After the cutting stages 4 and 8, it will be noticed that the cut wire gets pushed downwards slightly. This is corrected by repositioning the cut wire as illustrated at stage 9. The finished bobbin illustrated in Figure 12 is provided with the terminal pins 4 in a particularly efficient manner and one which lends itself to mass production. It is to be appreciated that the embodiment of the invention described above has been given by way of example only and that modifications may be effected. Thus, for example, the shape of the forming blade 26 (which locates in a top slot 28 in the moulded bobbin body 10) could be thicker and/or shorter than is shown. The precise apparatus shown for cutting and bending the terminal pins has been illustrated diagrammatically and it will be appreciated that such apparatus can be operated electrically, pneumatically or hydraulically. CLAIMS

1. A transformer bobbin having at least one self-locking terminal pin, the terminal pin being self-locking by being bent through substantially 900 in two different planes which are at substantially 900 to each other.

2. A transformer bobbin according to claim 1 and having four of the self-locking terminal pins.

3. A transformer bobbin according to claim 1 or claim 2 in which the or reach terminal pin is made from electro solder coated copper wire.

4. A transformer bobbin according to claim 1 and comprising a moulded bobbin body formed of an electrically insulating material, the said at least one self-locking pin being mounted on the moulded bobbin body, a coil wound around a central hollow core part of the moulded bobbin body, and soft iron laminations supported by the moulded bobbin body.

5. A transformer bobbin according to claim 4 in which the coil is wrapped in an insulating tape.

6. A transformer bobbin according to claim 4 or claim 5 in which the soft iron laminations are Eshaped laminations.

7. A transformer bobbin according to claim 6 in which the coil and the laminations are coated in a resin or a varnish.

8. A transformer bobbin substantially as herein described with reference to the accompanying drawings.

9. A method of producing a transformer bobbin having at least one terminal pin, which method comprises feeding a length of wire from a roll through an aperture in a moulded bobbin body such that the wire rests on a forming blade which itself rests in a slot in the moulded bobbin body, rotating the forming blade through 900 to bend the wire in a first plane through 900, cutting the wire to form the terminal pin, and bending the cut end of the wire in two substantially 450 stages so that the cut end of the wire is bent through substantially 90 in a second plane which is at substantially 900 to the first plane.

10. A method according to claim 9 in which the cut wire is slightly displaced during the cutting step.

11. A method according to claim 10 in which the cut wire is repositioned to its former position before being bent in the two 450 bending stages.

12. A method according to any one of claims 9 to 11 in which the transformer bobbin is formed with four terminal pins, the terminal pins being formed in pairs on opposite sides of the transformer bobbin.

13. A method of producing a transformer bobbin having at least one terminal pin, substantially as herein described with reference to the accompanying drawings.