WO2007122461A2

WO2007122461A2 - Electrical contacts for conductive -material -saving electrical plugs and sockets

Info

Publication number: WO2007122461A2
Application number: PCT/IB2007/000665
Authority: WO
Inventors: Renato Rosi; Romano Rosi
Original assignee: Rosi S.N.C. Di Rosi Romano & Renato
Priority date: 2006-03-13
Filing date: 2007-03-09
Publication date: 2007-11-01
Also published as: ITPC20060011A1; WO2007122461A3

Abstract

The present invention refers to a conductive -material - saving electrical contact for electrical plugs and sockets for industrial and/or tertiary use characterised by comprising at least one core support (30, 30’) made from sturdy material, and a cover sleeve (20) supported by said core (30, 30’) and made from conductive material, said core (30, 30’) and said sleeve (20) being joined so as to form a single body (10, 10') .

Description

ELECTRICAL CONTACTS FOR CONDUCTIVE-MATERIAL-SAVING ELECTRICAL PLUGS AND SOCKETS

The present invention refers to an electrical contact for conductive-material-saving electrical plugs and sockets.

By the term electrical plug is meant a mechanical connector comprising a connecting body made from insulating material supporting a plurality of pin-like male electrical contacts. Analogously, the electrical socket comprises a connector made of insulating material containing a plurality of socket-like (female) electrical contacts which are complimentary to the pins of the corresponding plug, in order to allow one to couple with the other.

The contacts of the electrical socket are preferably female in nature for reasons of safety. Indeed, it is preferred that said contacts not be exposed externally since they are perpetually maintained at a potential difference (voltage) .

The most commonly used electrical plugs and sockets have one live contact and one reference contact, known as neutral. In many electrical plugs and sockets, besides the live and neutral contacts, there is also a third earth contact .

On the other hand, industrial devices which use single- phase and three-phase supplies use special electrical sockets and plugs which can have up to four or five contacts, depending on the type of connection. Furthermore, there are a range of electrical sockets and plugs having one, two or more contacts, which are used to supply DC current to electrical or electronic equipment .

At the most interior end of the electrical contacts within the socket or plug, said contacts have a part for connecting to electrical cables . The connections can vary according to how the electrical contacts are made, and in particular may be screw type (figure 2.1), faston type (figure 2.2), plate type (figure 2.3), soldered (figure 2.4) or some other type of connection. The material generally used to date to make the contacts of electrical plugs and sockets (pins and sockets) is brass, optionally tin or nickel plated. Furthermore, the dimensions of such contacts depend on the electrical capacity, and are dictated by current regulations . Brass is a copper and zinc based metal alloy and has significant technical importance in the manufacture of electrical contacts due its excellent conductance. Furthermore, said material has good mechanical stability, despite occasionally being prone to wear due to the mechanical stresses envisaged during use of the electrical contacts. In recent years, in the light of declining availability and increasing demand for the acquisition of brass, the market for this material has experienced significant growth in terms of competition, reaching very high prices and poor availability.

Furthermore, the market for the raw materials from which brass alloy is made is also susceptible to significant price rises, and forecasts predict further increases. Thus the price of brass impacts ever more on the production costs of electrical plugs and sockets, reducing the profitability of such products, forcing the prices of the finished products to increase. Furthermore, considering that making the connectors of the electrical contacts involves starting from full rough bars in order to achieve the desired shape, there is further waste of said conducting material. The scope of the present invention is that of obviating the above-mentioned drawbacks, particularly that of realising an electrical contact for electrical plugs and sockets which has low manufacturing costs while offering optimal electrical conductivity. Another scope of the present invention is that of providing an electrical contact for electrical plugs and sockets with improved mechanical characteristics.

A further scope of the present invention is that of devising an electrical contact for electrical plugs and sockets with less susceptibility to wear, and hence greater durability, with respect to traditional contacts .

The last, but by no means final scope of the invention is that of reducing the waste of conductive material during the manufacture of an electrical contact .

These and other scopes according to the present invention are achieved by realising an electrical contact as divulged in claim 1. Further characteristics of the device are the subject of the ancillary claims.

The characteristics and advantages of an electrical contact according to the present invention will be clearer from the following description, by way of non- limiting example, referring to the enclosed schematic diagrams, wherein:

- figure 1.1 shows a raised side view of an electrical plug pertaining to the state of the art;

- figure 1.2 is a cross sectional view along axis I-I of the plug of figure 1.1_/

- figure 1.3 is a plan view of the plug of figure 1.1;

- figure 2.1 is a perspective view of a first known Plug;

- figure 2.2 is a perspective view of a second known plug;

- figure 2.3 is a perspective view of a third known plug; - figure 2.4 is a perspective view of a fourth known Plug;

- figure 3.1 is a plan view of a first embodiment of the electrical pin contact according to the invention; - figure 3.2 is a cross sectional view of the electrical contact of figure 3.1;

- figure 4.1 is a raised side view of the core of a first embodiment according to the invention;

- figure 4.2 is a perspective view of the core of figure 4.1;

- figure 5.1 is a side view of the partial cover sleeve of a first embodiment according to the invention;

- figure 5.2 is a perspective view of the sleeve of figure 5.1; - figure 6 shows a pin-socket assembly according to the present invention;

- figure 7.1 shows the core of a second embodiment of the electrical contact pin according to the present invention; - figure 7.2 is a plan view of the electrical contact of figure 7.1; figure 7.3 is a cross sectional view of the electrical contact of figure 7.1;

- figure 8 shows a raised side view of a contact rod used in a second embodiment of the electrical contact pin according to the present invention; - figure 9.1 is a perspective view of a first variant of the rod of figure 8;

- figure 9.2 is a perspective view of a second variant of the rod of figure 8 ; - figure 9.3 is a perspective view of a third variant of the rod of figure 8 ;

- figure 9.4 is a perspective view of a fourth variant of the rod of figure 8; figure 10.1 shows a raised side view of the electrical contact pin according to the second embodiment;

- figure 10.2 is a plan view of the electrical contact of figure 10.1; figure 10.3 is a cross sectional view of the electrical contact of figure 10.1.

With reference to the above figures, an electrical contact pin according to a first embodiment of the invention, indicated overall by the number 10, is shown first of all. Said pin has an essentially cylindrical shape and has a first forward section 11 capable of protruding from an electrical plug, inside which it is housed, and a second rear section 12 capable of being housed inside said plug. The size and shape of the front section 11 are dictated by the regulations, while the rear section 12 is made differently according to need, and particularly in the variations with screw connectors 13, faston connectors 14, plate connectors 15, soldered connectors 16 or other types of connectors .

According to the invention, the electrical contact 10 is constituted by at least two pieces 20,30 made from different materials.

A first piece, known as the core support 30, is made from a support material with sufficient conductivity characteristics, and acts as a mechanical support frame for the second piece 20, known as the cover sleeve, made from a conductor with excellent conductivity, usually a noble material.

The core support 30 comprises a first part 33 which forms the electrical cable connector 13-16, a second cylindrical part 32 with diameter corresponding to the overall diameter of the electrical contact 10 and a third housing section 31 of the sleeve 20. The cover sleeve 20 is a hollow cylindrical body, open on one side and with outer dimensions corresponding to the dimensions dictated by the regulations in relation to the first part 11 of the electrical contact pin 10, in relation to the capacity, in Amperes, which said contact pin 10 must carry. The housing section 31 of the core 30 is made with a reduced diameter with respect to the diameter of the second part 32, and in particular has a cross section complimentary to the cross section of the cavity of the sleeve 20.

The cover sleeve 20 is thus fitted over the housing section 31 of the core support 30 and indivisibly bound to the same so as to form a single body 10.

The electrical contact pin 10 thus formed is predominantly made from a sturdy material capable of withstanding the mechanical stresses envisaged for the electrical contact during use and having sufficient conductivity, but with a much reduced cost with respect to the noble conducting material.

Furthermore, the contact 13-16 is realised by starting from the core 30 made from sturdy material, thus eliminating any waste of conductive material. In order to obtain electrical characteristics equal to an electrical contact pin made entirely from conductive material, the housing part 31 is located at the area of contact between the electrical contact pin 10 and the electrical contact female socket 50. This way, both the areas in the electrical contacts 10,50 coming into direct contact with one another are made from conductive material .

The electrical contact pin 10 thus obtained has shape, size and electrical characteristics essentially the same as an electrical contact pin made entirely from conductive material, but with improved mechanical characteristics and substantially lower manufacturing costs .

Preferably, the core 30 is made from steel, while the sleeve 20 is made from brass. The assembled pin 10 is optionally treated in order to prevent oxidation of the parts, such as for example, by nickel plating, or by processes to improve conduction, such as for example copper, silver or gold plating.

In a second embodiment of the electrical contact pin 10' according to the invention, the use of a connecting rod 40 is envisaged, itself also made from conductive material, not necessarily the same as the material used to make the sleeve 20.

In this embodiment, in the core 30' there is a longitudinal seat 34 for housing said connecting rod 40 which completely fills the aforementioned seat 34.

Indeed, the connecting rod 40 is housed so as to form a single continuous body with the sleeve 20 and the core

30' . The end 41 of the rod 40 facing towards the first part

33 of the core 30' which forms the connection with electrical cables, partly or completely forms said connection 13 ^■ -16 ' .

For this reason, said end 41 of the rod 40 has a structure capable of forming a screw connection 13 ', a faston connection 14 ', a plate connection 15 ', a soldered connection 16' or another type of connection. This way, a continuous electrical connection, made entirely using conductive material, is made between the sleeve 20, and hence the female socket 50 of the electrical socket, and the connector 13' -16 ', thus providing electrical continuity by means of the highest conducting material .

The characteristics of the device forming the subject of the present invention, just like the corresponding advantages, are clear from the above description. Finally, it is obvious that the device thus conceived can undergo numerous modifications and variations, all falling under the invention; furthermore, all details can be substituted with technically equivalent components. In practice, the materials used, as well as the dimensions, can be of any kind, according to the technical requirements .

Claims

1. An electrical contact for an electrical plug for industrial and/or tertiary use characterised by comprising at least one core support (30,30^!) made from sturdy material and a cover sleeve (20) supported by said core (30,30') and made from conducting material, said core (30,3O¹) and said sleeve (20) being joined so as to form a single body (10,10') .

2. The electrical contact according to claim 1 characterised in that said core (30,30') comprises a first part (33) shaped as a connector (13-16) , a second cylindrical part (32) with cross section corresponding to the overall cross section of said electrical contact (10) and a third housing part (31) for said cover sleeve (20) .

3. The electrical contact according to claim 2, characterised in that said third housing part (31) is made with a smaller diameter with respect to said second part (32) .

4. The electrical contact according to claims 1 to 3 characterised in that said cover sleeve (20) has a hollow cylindrical body open at one side and with outer dimensions dictated by the regulations .

5. The electrical contact according to claims 1 to 4 characterised in that within said core (30') is housed a rod (40) made from a conductive material which joins with said sleeve (20) giving said electrical contact (10') electrical continuity by means of more conductive material .

6. The electrical contact according to claim 5 characterised in that said core (30') comprises a longitudinal seating (34) for housing said rod (40) .

7. The electrical contact according to claims 5 or 6 characterised in that said first connecting part (33) of said core (30') is at least partially constituted by one end (41) of said rod (40) .

8. The electrical contact according to any of the preceding claims characterised in that said sturdy material of said core (30) is steel.

9. The electrical contact according to any of the preceding claims characterised in that said conductive material of said sleeve (20) is brass.

10. The electrical contact according to any of the preceding claims characterised in that said conductive material of said rod (40) is brass.