Many types of electrical connectors are known. One known type of connector system, used in the aerospace industry in particular, comprises a plug and socket, each for fitting to the end of a respective signal-conveying cable. The cables contain up to a predetermined maximum number of signal conductors. The plug contains an array of passages equal in number to the predetermined maximum number of conductors in the cable. Pin elements are then provided in a sufficient number of the passages to provide a pin for each conductor in the cable. Each pin element contains a conductor receiving portion at one end for receiving a conductor of a cable and a pin at the other end for connecting to a corresponding socket element in the socket. The remaining passages may remain empty. It will be appreciated that, in a sense, the plug is configurable in that the number and disposition of pin elements in the array can be varied in dependence upon the number of conductors in the cable.

In the same way, the socket is provided with an array of passages equal in number to the predetermined maximum number of conductors in the cable. A sufficient number of the passages in the socket, equal to the number of conductors actually present in the cable, contain socket elements. One end of each socket element is adapted to receive a cable conductor and the other end is adapted to receive a pin of a respective pin element of the plug.

Each passage in the plug contains an enlarged chamber, the ends of which define shoulders in the passage. A collet extends between one of the shoulders and a pin element in the passage, and urges the pin element against the other shoulder to hold the pin element in the passage. Each collet can be disengaged from its respective pin, allowing the pin to be withdrawn from the plug body. Thus, the arrangement of pins in the array can be configured or reconfigured as desired.

The plug is manufactured in two parts, each containing an array of passage portions having a stepped diameter. The two parts are joined together using an adhesive.

The socket has a similar two piece construction which provides passages having chambers with shoulders and containing collets for restraining socket elements.

A disadvantage of this known design of connector is that the interface in the plug or socket is vulnerable to electrical leakage between the different pin or socket elements. This means that the connectors need to be tested and leads to a high wastage rate. Even worse; if the adhesive fails, electrical leakage can have potentially serious consequences in use.

The present invention aims to ameliorate at least some of the aforementioned disadvantages.

According to one aspect, the invention provides a method of making an electrical connector body comprising forming a number of passages in the body and, in each passage, creating a chamber by: inserting a tool into the passage and using the tool to laterally enlarge a part of the passage to form a chamber defining shoulders for holding in place an electrical connection element located in the passage.

The invention also consists in an electrical connector body having a number of passages through it, each passage having a laterally enlarged section forming a chamber, the ends of the chamber defining shoulders for holding in place an electrical connection element located in the passage, wherein the body is of unitary construction.

Thus the electrical connector body does not have a join and avoids the attendant disadvantages.

In a preferred embodiment, a plurality of passages are formed, each passage having a chamber for holding in place an electrical connection element located therein.

Electrical connection elements may be inserted in one or more of the passages in the electrical connector body. Preferably a connection element is held in place by being urged against a shoulder of the chamber in the respective passage by a resilient means, such as a collet, which extends between the connection element and the other shoulder of the chamber. The resilient means is compressible for insertion through the passage into the chamber, and is expandable in the chamber so as to be retained therein. Preferably, the resilient means can be disengaged from the connection element to allow the latter's removal from its corresponding passage. A connection element may be provided with a collar for engaging a shoulder of the chamber and the resilient means.

The electrical connection element may be a pin element and the connector body may be a plug body. A pin element may be a pin connected to a conductor receiving portion.

Alternatively, the electrical connection element may be a socket element and the connector body may be a socket body. A socket element has a conductor receiving portion and a socket for receiving a pin.

In a preferred method of manufacture, the or each passage is cut from the connector body, e. g. by drilling. Optionally, the radially enlarged section or sections can be machined using a circular interpolation technique.

By way of example only, an embodiment of the invention will now be described with reference to Figures 1 to 4, in which: Figure 1 is a partial cross-section through a prior art plug; Figure 2 is a partial cross-section through a prior art socket; Figure 3 is a partial cross-section through a plug according to the invention; and Figure 4 is a partial cross-section through a socket according to the invention.

The plug 100 of Figure 1 comprises a two part body, having a front part 110 and a rear part 112. The two parts 110 and 112 are joined together by adhesive along line 114. The plug 100 contains an array of passages extending between its front and rear faces, and one of these is shown and is illustrated as containing a pin element 116. Pin element 116 is shown in side elevation and not in cross-section.

The pin element 116 is loaded into the passage from the rear face until the pin 118 of the pin element protrudes from the front face of the plug, with collar 120 of pin element 116 abutting a spacer ring 122 in the passage. The rear section of the pin element 116 comprises a conductor receiving part 124. The conductor receiving part 124 receives a conductor of a cable which is to be attached to the plug 100. Other passages in plug 100 contain pin elements like 116 for connecting to other conductors of the cable.

With regard to pin element 116, the face of its collar 120 distant from spacer ring 122 is contacted by a resilient collet 126 positioned in the passage. The collet 126 extends in compression between the collar 120 and a shoulder 129 in the passage. The collet 126 urges the collar 120, and hence the spacer ring 122, against a shoulder 128 in the passage.

Effectively, shoulders 128 and 129 define a radially enlarged chamber extending between them, the chamber containing the spacer ring 122, the section of the pin element 116 bearing collar 120, and collet 129. The portions of the passage extending away from the chamber obviously have a smaller diameter than that of the chamber. It will be apparent that the portion of the passage extending away from the chamber to the front of the body has a smaller diameter than collar 120 so that shoulder 128 restrains forward movement of the pin element 116. The portion of the passage extending away from the chamber to the rear of the body has a larger diameter than the aforementioned passage portion since it must be large enough to admit the collar 120 in order to allow insertion and withdrawal of the pin element 116 through the rear face of the body.

A tool can be inserted into the passage from the rear end of the plug 100 to depress the collet 126 allowing the pin element 116 to move rearwardly and thus be removed from the passage. In this way, the plug 100 can be configured so as to provide a desired number of the passages with corresponding pin elements 116. The front face of the plug 100 is provided with a face seal 130 to prevent contamination of the plug and to cushion the front surface of the plug when connected to a corresponding socket.

Figure 2 shows a socket body 200 comprising a front part 210 and a rear part 212. The parts 210 and 212 are joined together by adhesive along join line 214. The socket contains an array of passages extending between its front and rear faces. One of the passages is shown and is illustrated as containing socket element 216. Socket element 216 is shown in side elevation and not in cross-section.

The socket element 216 comprises a socket portion 218 extending to a mouth 220 on the front of the front socket part 210. The mouth 220 is flared so as to help guide a pin of a corresponding plug into the passage to connect to the socket portion 218. The socket portion 218 comprises a sleeve into which the pin 118 is received. The socket portion 218 has an internal collet into which the pin 118 is received. The socket element 216 also comprises a conductor receiving portion 222 at its rear end. The purpose of the conductor receiving portion 222 is to establish a connection with a conductor of a cable associated with the socket 200.

Like the passages provided in plug 100 the passage containing socket element 216 comprises a chamber of enlarged diameter which extends between shoulders 224 and 225.

A spacer ring 226 is located in the chamber adjacent shoulder 224. The socket element 216 has a collar 228 which is urged against the spacer ring 226 by collet 230 which is also located in the wider portion of the passage. The collet 230 is resilient and extends in compression between collar 228 and shoulder 225. The socket element 222 may be removed from the passage using a tool to disengage the collet 230 from the collar 228.

Spacer ring 226 and collet 230 position the socket element 222 correctly in the passage.

The portions of the passage extending away from the chamber have smaller diameters than the chamber. The portion extending to the front of the body has a diameter smaller than collar 228 and the portion extending to the rear of the body has a diameter greater than collar 228.

In use, a cable is attached to the rear of plug 100 with the conductors of the cable connected to the conductor receiving portions 124 of respective pin elements in the plug. Similarly, a cable is connected to the rear face of socket 200, with conductors of the cable received in the conductor receiving portions 222 of corresponding socket elements 216 of the socket.

The cables can then be connected by inserting the pins 118 of the plug 100 into the mouths 220 provided in the socket 200. The front face of one of the plug 100 and the socket 200 is provided with a feature (not shown) which fits with a corresponding feature (not shown) of the front face of the other of the plug 100 and the socket 200 so that the plug 100 and socket 200 are aligned correctly when they are connected together. This ensures that the pins 118 of the plug 100 will not be inserted into passages of the socket 200 which do not contain socket elements 222. Thus, misconnection or the failure to make a connection can be avoided.

The plug 300 of Figure 3 comprises a unitary body 310 produced from a single piece of plastics material. In other respects, it is similar to plug 100. For example, it has an array of passages which can contain pin elements such as pin element 312 shown (in side elevation). The passages are formed with a small diameter section leading in from the front face of the plug body 310 to a large diameter chamber (containing collet 314, for example) which leads to, in turn, an intermediate diameter section extending to the rear face of the body 310. As previously with plug 100, the ends of the chamber define shoulders, one of which restrains a collar on the pin element 312, and the other of which provides an abutment for collet 314. The collar is urged against the adjacent shoulder by a collet 314 so as to correctly position the pin element 312 in the passage. The plug 300 is provided with a face seal 316 like that of plug 100. The main differences between plug 300 and plug 100 are that plug 300 has a unitary body 310 and does not require a spacer ring adjacent the collar of the pin element 312. The spacer ring 128 is needed in plug 100 to ensure that collet 126 is not located at join 114 to prevent electrical tracking or leakage, and also to help locate parts 110 and 112 when they are being assembled together.

Figure 4 illustrates a socket 400 to which the plug 300 can be connected. The socket 400 has a socket body 410 of unitary construction, produced from a single piece of plastics material. Like socket 300, socket 400 has an array of passages extending between its front and rear faces. One of these passages is shown, and is illustrated as containing socket element 412 (shown in side elevation). The passage shown has a first small diameter section extending inwardly from the front face of the socket body 410 to a large diameter chamber which leads, in turn, to an intermediate diameter section extending away to the rear face of the socket body 410. The ends of the chamber define shoulders. One of the shoulders restrains a collar on the socket element 412 and a collet 414 extends between the other shoulder and the collar. The collet 414 urges the collar against the adjacent shoulder.

In summary, the socket 400 is similar to socket 200, except in that the socket body 410 is a single element and no spacer ring is required.

The unitary construction of the socket body 410 and the plug body 310 provides for more economical manufacture because these parts no longer consist of two separate parts which have to be aligned precisely (to ensure that the passages are continuous and have the correct diameter) and adhered together. Further, the elimination of the use of adhesive results in a stronger connector body which can be used at higher temperatures and in the reduction of crosstalk between pin/socket elements. The component count is also advantageously reduced since spacer rings are not required.

The unitary connector bodies, i. e. plug body 310 and socket body 410 are manufactured, broadly speaking, in the same way. First, the exterior shape of the connector body is formed by moulding, cutting or otherwise shaping a piece of plastics material to produce the appropriate contours. A tool is then used to produce the passages in the connector body. The tool is positioned over the rear face of the connector body, i. e. that face which does not abut a face of another connector body in use. The tool is aligned with the axis of a passage to be drilled and drills through the connector body from the rear face to the front face to create an initial passage having a diameter equal to that of the small diameter portion of the finished passage (i. e., the portion which extends from the front face to the chamber). The tool is then positioned in the initial passage at the location where the chamber is to be created. The tool is then used to cut the large diameter chamber in the passage. The tool is then repositioned to enlarge the portion of the passage extending from the chamber to the rear face of the body to produce the intermediate diameter portion. The tool is then extracted and positioned over the rear face of the connector body at the axis of the next passage to be drilled.