GB1583149A - Transformer assemblies - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO TRANSFORMER ASSEMBLIES (71) We, THE PLESSEY COMPANY LIMI TED, a British Company of Vicarage Lane, Ilford, Essex, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to transformer assemblies, and more particularly but not exclusively it relates to hybrid transformer assemblies.

According to the present invention a transformer assembly comprises a transformer, the windings of which are connected to terminals which are integral parts of the transformer, a printed circuit board on which the transformer is mounted with said terminals projecting through holes in the board and electrically connected to printed circuit track on the board, a base positioned orthogonally with respect to the printed circuit board and including terminals coupled to the transformer windings via the printed circuit board track, and a frame connected to the base and supporting the printed circuit board.

The frame may be adapted to support a screening can arranged to enclose the assembly, the open end of the can being fitted to the base.

Two transformers may be mounted on the board so as to define a hybrid transformer of the kind used in telephone circuitry to facilitate two or four wire splitting or four to two wire combining. The frame may comprise a generally C-shaped member the printed circuit board being secured to the generally vertical limb of the C-shaped member, the can being secured to one of the generally horizontal limbs and the base being secured to the other generally horizontal limb. The C-shaped member may be fabricated of plate having press-formed upstanding portions which locate in complementary slots in the printed circuit boards, the upstanding portions being bifurcated to facilitate stagging whereby the printed circuit board is firmly secured to the frame and held in spaced apart relationship with the frame by shoulders on the up- standing portion.

One embodiment of the invention will now be described by way of example with reference to the drawings, in which; Figure la is a side view partly in section of a hybrid transformer assembly, Figure ib is a sectional end view along the line A-A of the transformer assembly shown in Figure la, and Figure 2 is a schematic block diagram of a circuit arrangement utilising a hybrid transformer as shown in Figures la and Ib.

Referring now to the drawings, the hybrid transformer assembly comprises two similar transformers 1 and 2 having lamination stacks la and ib respectively. The transformers include windings supported on bobbins 3 and 4, the windings being terminated at tags5 which are connected to terminals 6 which are arranged to locate in complementary holes in a printed circuit board 7 on which the transformers 1 and 2 are mounted. The transformers are rigidly secred to the board by means of screws 8. By providing the tags 5, connection between various parts of the windings carried on the bobbins 3 and 4 can be made externally of the windings which simplifies construction and avoids the need for providing connections within insulation layers on the bobbin.

Connections between the transformers are affected by means of the copper conductors carried on the printed circuit board and terminal lands on the printed circuit board 7 are connected to output terminals 9 carried on a base 10 via leads such as the leads 10a shown in Figure la.

The printed circuit board 7 is mounted on a press-formed C-shaped frame 11, upstanding lugs 12 being provided on the frame which locate in complementary slots in the board 7, the upstanding lugs being bifurcated at their ends so as to facilitate stagging whereby the printed circuit board 7 is rigidly secured to the C-shaped frame 11, the lugs 12 being formed to define shoulders on which the board 7 is supported and spaced from the frame 11. Whilst the substantially vertical part 11a of the C-shaped frame 11 supports the printed circuit board 7, one horizontal part 1 lb is secured by means of screws 12a to the base 10 and the other substantially horizontal part 11c supports a screening can 13 which encloses the transformers 1 and 2 and fits on to the base 10.

A hybrid transformer assembly of the kind shown finds application in telephone cicuitry and as shown in Figure 2 usually serves to provide two to four wire splitting or four to two wire combining. In Figure 2 a pair of hybrid transformers 14a and 14b are shown, the transformers receiving a two-wire input and providing a four-wire output in opposite directions to or from amplifiers 15 and 16 as appropriate. Such transformers are very well known to those skilled in the art and will not therefore be further described herein.

WHAT WE CLAIM IS: 1. A transformer assembly comprising a transformer the windings of which are connected to terminals which are integral parts of the transformer, a printed circuit board on which the transformer is mounted with said terminals projecting through holes in the board and electrically connected to printed circuit track on the board, a base positioned orthogonally with respect to the printed circuit board and including terminals coupled to the transformer windings via the printed circuit board track, and a frame connected to the base and supporting the printed circuit board.

2. A transformer assembly as claimed in claim 1, wherein the frame is adapted to support a screening can arranged to enclose the assembly, the open end of the can being fitted to the base.

3. A transformer assembly as claimed in claim 1 or claim 2, wherein two transformers are mounted on the said board so as to define a hybrid transformer.

4. A transformer assembly as claimed in claim 2 or claim 3, wherein the frame comprises a generally C-shaped member, the printed circuit board being secured to the generally vertical limb of the C-shaped member, the can being secured to one of the generally horizontal limbs of the C-shaped member and the base being secured to the other generally horizontal limb.

5. A transformer assembly as claimed in claim 4 wherein the C-shaped member is fabricated from plate so as to have pressformed upstanding portions which locate in complementary slots in the printed circuit board, the upstanding portions being bifurcated to facilitate stagging whereby the printed circuit board is firmly secured to the frame and held in spaced apart relationship with the frame by shoulders on the upstanding portion.

6. A transformer assembly substantially as hereinbefore described with reference to the drawings accompanying the Complete Specification.

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

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. from the frame 11. Whilst the substantially vertical part 11a of the C-shaped frame 11 supports the printed circuit board 7, one horizontal part 1 lb is secured by means of screws 12a to the base 10 and the other substantially horizontal part 11c supports a screening can 13 which encloses the transformers 1 and 2 and fits on to the base 10. A hybrid transformer assembly of the kind shown finds application in telephone cicuitry and as shown in Figure 2 usually serves to provide two to four wire splitting or four to two wire combining. In Figure 2 a pair of hybrid transformers 14a and 14b are shown, the transformers receiving a two-wire input and providing a four-wire output in opposite directions to or from amplifiers 15 and 16 as appropriate. Such transformers are very well known to those skilled in the art and will not therefore be further described herein. WHAT WE CLAIM IS:

1. A transformer assembly comprising a transformer the windings of which are connected to terminals which are integral parts of the transformer, a printed circuit board on which the transformer is mounted with said terminals projecting through holes in the board and electrically connected to printed circuit track on the board, a base positioned orthogonally with respect to the printed circuit board and including terminals coupled to the transformer windings via the printed circuit board track, and a frame connected to the base and supporting the printed circuit board.

2. A transformer assembly as claimed in claim 1, wherein the frame is adapted to support a screening can arranged to enclose the assembly, the open end of the can being fitted to the base.

3. A transformer assembly as claimed in claim 1 or claim 2, wherein two transformers are mounted on the said board so as to define a hybrid transformer.

4. A transformer assembly as claimed in claim 2 or claim 3, wherein the frame comprises a generally C-shaped member, the printed circuit board being secured to the generally vertical limb of the C-shaped member, the can being secured to one of the generally horizontal limbs of the C-shaped member and the base being secured to the other generally horizontal limb.

5. A transformer assembly as claimed in claim 4 wherein the C-shaped member is fabricated from plate so as to have pressformed upstanding portions which locate in complementary slots in the printed circuit board, the upstanding portions being bifurcated to facilitate stagging whereby the printed circuit board is firmly secured to the frame and held in spaced apart relationship with the frame by shoulders on the upstanding portion.

6. A transformer assembly substantially as hereinbefore described with reference to the drawings accompanying the Complete Specification.