GB2144585A - A transformer bobbin - Google Patents

Abstract

A transformer bobbin (2) has a hollow coil portion for receiving a wound coil, and at least one terminal block (10), the terminal block having a plurality of spaced apart apertures (14) for receiving terminal pins, the terminal block having a plurality of outwardly projecting separator members (30) which are spaced apart to define slots (32) and which are for separating wires for the terminal pins, and the terminal pins being positioned one in each slot. <IMAGE>

Description

SPECIFICATION A transformer bobbin This invention relates to transformer bobbins.

Transformer bobbins are used to support the wound coils in transformers and are well known. The winding of the coils on the transformer bobbins can, however, be time consuming. Attempts to fully automate the winding of the coils on the bobbins has been frustrated by the coil winding apparatus having a tendency to foul the separator members which are employed in terminal blocks of the transformer bobbins for separating the wires which may form the wound coils and which are connected to terminal pins. The terminal pins are normally located in the separator members of the transformer bobbin.

It is an aim of the present invention to provide a transformer bobbin which reduces or obviates the above mentioned problem so that a wound coil can be provided on a hollow coil portion of the transformer bobbin by a substantially fully automated coil winding apparatus.

Accordingly, this invention prides a transformer bobbin comprising a hollow coil portion for receiving a wound coil, and a terminal block having apertures for receiving terminal pins and separator members defining slots therebetween, wherein the apertures are located in the slots between the separator members.

Hitherto, the terminal blocks have had the terminal pins positioned one in each of a plurality of the separator members, and the separator members have been separated from each other by slots. With the present inverition, the provision of the terminal pins in the terminal block but not in the separator members is itself a radical departure from the well established transformer bobbin design. The provision of the separator members in the slots is a further radical departure from the established transformer bobbin design. The two design departures together enable a much wider slot space to be achieved between adjacent separator members than in the known transformer bobbins. This larger spacing can then accommodate a pen-type coil winding apparatus, which could not be accommodated by the existing slots in the known and well established transformer bobbins.Thus the desired automated winding of the coils on the transformer bobbins can be achieved.

Usually, the transformer bobbin will be formed as a moulding of an electrically insulating material, the core portion, the terminal block and the separator members being integrally formed with each other.

Usually, there will be two terminal blocks and there may be seven or eleven terminal pins in the or each terminal block.

The terminal pins may be made from electro-soldar coated copper wire and, advantageously, the terminal pins are self-locking terminal pins of the type described and claimed in our co-pending Patent Application No.

8231822. Other types of terminal pins may however be employed if desired and for example, the terminal pins may have small swaged portions to enable them to be retained in their apertures.

The transformer bobbin may include the terminal pins and/or the wound coil.

The wound coil may be wrapped in an insulating tape.

The transformer bobbin may include soft iron laminations positioned in the core portion.

The soft iron laminations may be interlocking C-shaped laminations which interlock to form a rectangle.

The wrapped coil and the soft iron laminations may be coated in a resin or a varnish.

An embodiment of the invention will now be described solely by way of example and with reference to the accompanying drawing in which: Figures la and ib illustrate a top plan view of part of a transformer bobbin in accordance with the present invention; Figure 2 is a part section on the line AA shown in Fig. la; and Figure 3 is a part end view of the transformer bobbin illustrated in Fig. 1 a.

Referring to the drawings, there is shown a transformer bobbin 2 comprising a hollow coil portion (not shown) for receiving wound coils (not shown) on its surface. The coil portion may be provided with a circumferential upstanding wall member (not shown) for enabling the coils to be wound on the core portion in clockwise and anticlockwise directions.

The transformer bobbin 2 further comprises a pair of terminal blocks 10, only one of which is shown. Each terminal block 10 has seven spaced apart apertures 14, each for receiving a terminal pin, one of which terminal pins is shown schematically in Fig. 2 as terminal pin 1 6. The terminal pin 1 6 has an upper portion 1 8 which projects above the upper surface 20 of the terminal block 10.

The upper portion of the apertures 14 are of greater diameter than the lower portion and each terminal pin 1 6 has a kinked portion 22 which locates inside the upper portion of apertures 14 such that the terminal pins self lock in the apertures 14. The pin 1 6 also has a lower portion 24 which locates in and projects from the lower part of the aperture 14 which is formed as a slot 26. The portion 24 extends at right angles to the surface 28 surrounding the slot 26.

The terminal blocks 10 further comprise a plurality of separator members 30 which, as shown, define slots 32. The separator members 30 are for separating wires (not shown) which may be connected to the terminal pins 1 6. Normally, the wires for connection to the various terminal pins 1 6 must be kept separate from each other as otherwise electrical short-circuiting may occur. The terminal pins 1 6 are positioned in the slots 32.

It will be noticed that the slots 32 between the separator members 30 are relatively wide and, in the embodiment shown, have a width approximately twice the diameter of the widest portion of the apertures 14 which receive the kinked portion 22 of the terminal pins 1 6.

This is approximately twice the spacing achievable between the separator members 30 with hitherto transformer bobbins. These wider slots between the separator members 30 are extremely useful because the coils can be wound on the surface of the core portion from pen-like coil winding apparatus as the tip of the pen-like coil winding apparatus may be accomodated by the slots 32 between the pins 1 6 and their separator members 30 without fouling on the separator members 30 as was hitherto often the case. Thus the wound coils can be provided on the transformer bobbin 2 by a substantially fully automated and speedy process.

Usually, the hollow centre of the core portion will be provided with soft iron laminations which may comprise C-shaped laminations which are arranged to interlock to form annular laminations of rectangular shape.

The terminal blocks 10 may terminate in apertured portions which are each provided with a mounting hole which can be employed for mounting the transformer bobbin to a printed circuit board (not shown). The apertured portion at one end of the terminal blocks 10 may also be provided with a blind hole which may be used to support the transformer bobbin 2 when the bobbin is to be dipped in shellac or other resin.

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, as shown in Fig. 1 b, the apertures 14 can be off-centre in the slots 32, or the separator members 30 can be of narrower section than as shown in Fig. la.

Claims (11)

1. A transformer bobbin comprising a hollow coil portion for receiving a wound coil, and a terminal block having apertures for receiving terminal pins and separator members defining slots therebetween, wherein the apertures are located in the slots between the separator members.

2. A bobbin according to claim 1 wherein the terminal block is formed integrally with the coil portion.

3. A bobbin according to claim 1 or claim 2 wherein the coil portion and the terminal block are moulded from an electrically insulating material.

4. A bobbin according to any one of claims 1 to 3 wherein there are two terminal blocks.

5. A bobbin according to any one of the preceding claims wherein each terminal block has seven apertures.

6. A bobbin according to any one of the claims 1 to 4 wherein each terminal block has eleven apertures.

7. A bobbin according to any one of the preceding claims including soft iron iaminations located in the hollow coil portion.

8. A bobbin according to claim 7 wherein the soft iron laminations comprise C-shaped laminations arranged to interlock to form annular laminations of rectangular shape.

9. A bobbin according to any one of the preceding claims including the wound coil and the terminal pins.

10. A bobbin according to claim 9 wherein the terminal pins are arranged to self lock in the apertures.

11. A bobbin substantially as hereinbefore described with reference to the accompanying drawings.