AU740436B2 - A transformer - Google Patents

Description

Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

(ORIGINAL)

E b Name of Applicant: Actual Inventors: Address for Service: ATCO CONTROLS PTY. LTD., A.C.N. 005 182 481, of 130 Melrose Drive, Tullamarine, Victoria 3043, Australia Zeljko LUKIN; Daniel Shoon Chong YONG; and Barry John

FOREMAN

DAVIES COLLISON CAVE, Patent Attorneys, of 1 Little Collins Street, Melbourne, Victoria 3000, Australia "A TRANSFORMER" Invention Title: Details of Associated Provisional Application No: P05812/97 The following statement is a full description of this invention, including the best method of performing it known to us: P:\OPER\DBW\PO5812.97 2513/98 -2- A TRANSORMiER The present invention relates to a transformer, and in particular to a transformer for domestic lighting applications.

Transformers for domestic lighting applications are configured for connecting the primary winding to a first power cord, which is connected to the mains supply, and for connecting the secondary winding to a second power cord which provides extra low voltage for a light assembly. The cords are normally clamped to the transformer by a screw and clamp arrangement. Difficulties are commonly encountered by an installer when the mains power cord available at the installation location cannot be connected directly to the transformer, because the transformer caters for only one type of cord. Installers normally deal with this problem by connecting the type of power cord which the transformer is able to 15 accept and then splicing that power cord to the one which is connected to the main supply.

This of course is inefficient and cumbersome, and can also prove dangerous when splicing is not performed correctly. The current clamping arrangement for power cords has also proved cumbersome for installers.

S 20 Additionally for the primary side of the transformer there are a number of Srequirements which should be met. Installers or people handling the transformer should not be able to make any accidental contact with live parts, and accordingly a cover should be provided for all terminals, but which also allows access to the terminals for installation. At least three terminals and an optional connection of an earth conductor should be allowed. It should also be possible to loop the main supply off to another transformer.

In accordance with the present invention there is provided a transformer including an enclosed terminal bay having both an opening and an anchorage structure for different types of power cord, said anchorage structure being a structure about which said cord is bent to anchor said cord in said bay.

P:\OPER\DBW\PO5812.97 25/3/98 -3- Advantageously the anchorage structure allows different types of power cord to be anchored in the bay without the use of any additional fixing device, such as a clamp and screw.

Preferably the terminal bay includes a plurality of terminals which allow termination of conductors of the cord. Preferably the terminal bay includes a lid to allow access to the anchorage structure and terminals. The lid preferably has a hinged attachment to the bay and can be snap fitted into a closed position to cover an end of the cord engaged in the anchorage structure and connected to the terminals.

Preferably the terminal bay includes two of said opening which allow passage of said different types of power cord and inhibit passage of human digits.

o Preferably the anchorage structure includes a plurality of spaced walls in the terminal bay which establish a labyrinth of passages allowing the different types of power cord to be bent differently in the labyrinth and abut parts of said walls.

Preferably the terminal bay is for the primary end of said transformer and the secondary end includes a secondary anchorage structure and a secondary conductor terminating part. The secondary anchorage structure preferably includes a pillar around which different types of power cord can be bent before being terminated by the terminating part.

Preferably the secondary anchorage structure includes a hinged lid to close at least part of the structure and contain the power cord.

Preferred embodiments of the present invention are hereinafter described, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is a perspective view of a preferred embodiment of a transformer; Figure 2 is a plan view of the transformer of Figure 1; Figure 3 is a perspective view of the transformer with lids of the primary and secondary ends closed; P:\OPER\DBW\PO5812.97 25/3/98 -4- Figure 4 is a plan view of a terminal bay of the primary end of the transformer; Figures 5 to 8 are plan views of the primary end of the transformer with different types of power cord anchored therein; and Figure 9 is a plan view of the secondary end of the transformer.

A transformer 2, as shown in Figures 1 to 9, has an elongate housing 4 with a central part 6 and a primary end 8 and a secondary end 10. The central part 6 houses a transformer that can step down a mains voltage of about 240 volts to an extra low voltage of less than volts, which is particularly useful for domestic lighting applications. At least three terminals 12 for the primary winding of the transformer are provided in a terminal bay 14 of the primary end 8 of the housing 4. Terminals for the secondary winding are provided in an enclosed terminal part 16 of the secondary end The terminal bay 14 of the primary end 8 has two openings 20 and 22 and an 15 anchorage structure established by different parts in the primary end 8. The anchorage structure is able to receive and anchor different types of power cord which have conductor sizes ranging from about 0.75 mm 2 to 2.5 mm 2 The anchorage structure provides a labyrinth of different passages about which the different types of cord can be bent and secured. The anchorage structure is defined by: The outer walls 24 and 25 of the primary end, and in particular the ends 26 and 28 of the walls 24 adjacent the openings 20 and 22, respectively.

(ii) The side walls 30 and 32 of a central portion 34 of the primary end i which are substantially parallel to and define the openings 20 and 22 with the wall ends 26 and 28, respectively. The openings 20 and 22 have a minimum width of 7.4 mm (iii) Pillars 36 and 38 which extend into the terminal bay 14 from the walls 24 and 25, respectively.

(iv) A clamping structure 40 which has a first doglegged end 42 which defines a first passage (width 3.6 mm) with a back wall 33 of the central portion 34 and a second end 44 which defines a second passage (width P:\OPER\DBW\PO5812.97 25/3/98 6.7 mm) with the back wall 33 of the central portion 34. The clamping structure 40 has a space 35, as shown in Figure 4, between walls of the first and second ends 42 and 44 which defines a third passage (width 6.7 mm).

The second and third passages hold and allow a cord with conductor sizes up to mm 2 to be placed therethrough, whereas the first passage allows cord with conductor sizes up to 1 mm 2 to be held and passed therethrough. Fourth and fifth passages (width 8.6 mm) are defined between each of the pillars 36 and 38 and the first and second ends 42 and 44, respectively, of the clamping structure 40. A power cord which enters one of the openings 20 and 22 is bent around the wall 30 or 32 of the central portion 34 and through at least one of the passages, as described hereinafter, so as to be engaged by the anchorage structure and held in place thereby. The primary end 8 has a lid 50 which is hinged to the central part 6 and can be closed so as to enclose the terminal bay 14 and snap fits onto a cooperating part 52 of the central portion 34. By enclosing the terminal bay 14, the terminals 12 are protected and 15 the openings 20 and 22 are configured such that human digits cannot be inserted therein to contact the terminals 12.

For a first cord 54, as shown in Figure 5, the cord 54 is passed into the first opening and bent about the first wall 30 of the central portion 34. The cord is passed through the first passage so as to be held between the first end 42 of the clamp structure 40 and the back wall 33 of the central portion 34. The cord is then bent again so as to pass through the third passage, where the cord is then stripped so its conductors can be connected to the terminals 12, as shown in Figure 5. The manner in which the cord 54 is bent around the central portion 34 and the clamping structure 40 and held by the clamping structure 40 against the central portion 34, prevents the cord 54 from being pulled so as to exert a force on the conductors at their point of termination to the terminals 12. The cord 54 may be 2 core flat LD/OD flex or 2 core light (ordinary) duty flex 54, which can have conductor sizes of about 0.75 mm 2 to 1 mm 2 For a thicker cord 56, as shown in Figure 6, the cord 56 can be passed through the P:\OPER\DBW\PO5812.97 25/3/98 -6second opening 22 and bent on the second wall 32 of the central portion 34. The cord is then passed through the second passage between the second end 44 of the clamping structure and the back wall 33 of the central portion 34 and then bent again so as to be passed through the third passage. The cord is then stripped so its conductors can be connected to the terminals 12. The cord 56 is effectively clamped in the second and third passages. Similar to the thinner cord 54, the manner in which the cord 56 is bent around the central portion 34 and the clamping structure 40 and held by the clamping structure 40 against the central portion 34, prevents the cord 56 from being pulled so as to exert a force on the conductors at their point of termination to the terminals 12. The cord 56 may be 2 core heavy (ordinary) duty flex which can have a conductor size between 0.75 mm 2 to 1.5 mm 2 For an even thicker power cord 58, as shown in Figure 7, the cord 58 can be placed through one of the openings 20 or 22 and bent around the wall 30 or 32 of the central portion 34 and then passed through the fourth passage so as to be clamped between the first pillar 38 15 and the second end 42 of the clamping structure 40. The cord is then stripped so that the conductors can be connected to the terminals 12 and if an earth conductor is included, this can S" be connected to a fourth earth terminal 14, as shown in Figure 7. The cord 58 is held in the opening 20 by abutting the end 26 of the wall 24 and also engaging the wall 30 of the central part 34, whilst also being bent and held between the pillar 36 and the clamping structure so as to prevent the cable 58 being pulled so as to exert a force on the terminating points of the conductors. The thick cable 58 may be a power cable, such as a thermoplastic sheath (TPS), copper PVC 2 core flat, with or without the earth, 0.6/1 KV PVC insulated PVC, with a conductor size that can vary between 1 mm 2 to 2.5 mm 2 The terminal bay 14 can accommodate two power cables 58 inserted through respective openings 20 and 22 and held in the openings 29 and 22 and the fourth and fifth passages between the pillars 36 and 38 and the clamping structure 40, as shown in Figure 8.

This allows the main supply to be looped from one transformer to another.

The secondary end 10 is divided into two parts which are placed side by side, being P:\OPER\DBW\P05812.97 25/3198 -7the terminating part 16 and a cord anchorage part 17. The cord anchorage part 17 includes a recessed bay 19 in which is centrally disposed a Y-shaped pillar 60. Forked ends 62 and 64 of the pillar 60 are directed to the back comers 66 and 68 so that a cord 70 can be bent within the bay 19 around the forked ends 62 and 64 so as to engage the pillar at the ends 62 and 64, as shown in Figures 2 and 9. The cord 70 may be any size cord up to a power cable of conductor size 2.5 mm 2 After bending the cord about the pillar 60, its end can be stripped so that conductors 72 and 74 can be inserted into holes 76 and 78 of the terminating part 16.

Upper holes 80 and 82 are provided for the insertion of a screw driver so that the conductors 76 and 78 can be affixed to terminals in the terminating part 16. Once the cord is bent around the pillar 60, and the conductors terminated, a hinged lid 84 can be snapped shut onto the terminating part 16, as shown in Figures 3 and 4, so as to assist in retaining the cord 70 in Sthe recessed bay of the anchorage part 17. The cord 70 is bent within the anchorage part 17 so as to be held by the side walls 86 and 88 of the recessed bay 19 and the pillar 60 so that any pulling force exerted on the free part of the cord 70 is not exerted on the conductors 76 15 and 78. The width between the forked ends 62 and 64 and the side walls 86 and 88 is 6.2 mm.

The transformer 2 includes primary and secondary terminating ends 8 and 10 which allow different types and sizes of power cords to be terminated and securely anchored without requiring the use of cumbersome fixing devices, such as a screw and clamp arrangement.

Particularly for the primary end the terminals are safely enclosed and live parts shielded from .human digits, whilst also allowing for the main supply to be looped from transformer to -transformer.

Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention as' herein described with reference to the accompanying drawings.

Claims (13)

1. A transformer including an enclosed terminal bay having both an opening and an anchorage structure for different types of power cord, said anchorage structure being a structure about which said cord is bent to anchor said cord in said bay.

2. A transformer as claimed in claim 1, wherein said anchorage structure includes a plurality of spaced walls in the terminal bay which establish a labyrinth of passages allowing the different types of power cord to be bent differently in the labyrinth and abut parts of said walls.

3. A transformer as claimed in claim 2, wherein said different types are bent in different .oo. ones or combinations of said passages. *o

4. A transformer as claimed in claim 1, 2 or 3, wherein said terminal bay includes a plurality of terminals which allow termination of conductors of the cord.

5. A transformer as claimed in claim 4, wherein said terminal bay includes a lid to allow access to the anchorage structure and terminals.

6. A transformer as claimed in claim 5, wherein said lid has a hinged attachment to the too' bay and can be snap fitted into a closed position to cover an end of the cord engaged in the to anchorage structure and connected to the terminals.

7. A transformer as claimed in any one of the preceding claims, wherein said opening inhibits the passage of human digits.

8. A transformer as claimed in claim 7, -wherein said terminal bay includes two of said opening which allow passage of said different types of power cord and inhibit passage of human digits. P:\OPER\DBW\59524-98 clains.doc-6 September. 2)I1 -9-

9. A transformer as claimed in any one of the preceding claims, wherein a primary end of said transformer includes said terminal bay and a secondary end of said transformer includes a secondary anchorage structure and a secondary conductor terminating part.

10. A transformer as claimed in claim 9, wherein the secondary anchorage structure includes a pillar around which different types of power cord can be bent before being terminated by the terminating part.

11. A transformer as claimed in claim 10, wherein said secondary anchorage structure 10 includes a hinged lid to close at least part of the secondary anchorage structure and contain the power cord. S

12. A transformer as claimed in any one of the preceding claims, wherein said different types of power cord have conductor sizes ranging from about 0.75 mm 2 to 2.5 mm 2

13. A transformer substantially as hereinbefore described with reference to the accompanying drawings. 20 DATED this 6 t h day of September 2001 ATCO Controls Pty Ltd By its Patent Attorneys DAVIES COLLISON CAVE