GB2353414A - Coaxial cable harness production - Google Patents

Abstract

A cable harness having a complex connector arrangement is produced by stripping first ends of cables in a stepped formation to expose a braid 3, a dielectric 4 and an inner insulation jacket 5. A drain wire 10 is soldered onto the exposed braid and subsequently wound around the braid so that both ends of the wire extend along the length of each cable. The first ends are then terminated into individual connector parts 15 which are subsequently clipped together eg in pairs to form one or more complete connectors each surrounded by a housing 20. Second ends of the cables are then stripped and the conductors 6 are soldered to respective socket centre pins 31. Outer bodies 32, 33 are crimped onto the braids 3 and the cable ends are placed in a ledged slot (37, Figures 3(a), (b)) in a jig (35) with the connector bodies 33 passing through apertures in a common connector plate (42). Outer sockets (34) are then screwed onto the connector bodies 33.

Description

2353414 "A coaxial cable harness production procesf The invention relates

to a process for producing coaxial cable harnesses, and particularly such harnesses of a complex nature having a connector block at one end and having interconnected connectors at the other end.

One object of the invention is to provide for production of such harnesses in a manner whereby quality of the harnesses is excellent at the end of the process, and the harnesses are subsequently reliable in use for lengthy periods of tirne. 10 Another object is that the process be efficient.

According to the invention, there is provided a process for producing a coaxial cable harness, the process comprising the steps of15 cutting at least two coaxial cables to pre-set lengths; stripping first ends of the cables in a stepped configuration to successively expose a braid, a dielectric, and an inner jacket; applying a drain wire to each exposed braid, at the first end; terminating the exposed conductors and drain wires into a connector at the first end; 25 stripping the opposite, second, ends of the cables to expose the conductor and soldering the exposed conductor to a coaxial centre pin and mounting a connector around the centre pin; and mounting a plate of a connector block onto an upper surface of a jig having a slot comprising ledges, supporting the connectors at the second ends on the ledges so that they extend through apertures of the plate, and screwing outer sockets onto the connectors while they are supported in the jig.

In one embodiment, the jig comprises a plurality of side-by-side slots aligned with apertures of the plate, and the upper surface is recessed.

Preferably, the connector block is removed by pressing a pair of opposed ejection levers 10 pivotally connected to the jig and forming part of a side wall of each jig slot.

In one embodiment, the cables are stripped by an automatic tool having a pair of rotating blades.

Preferably, the drain wire is soldered to the braid and is wrapped around the braid whereby both ends of the drain wire extend alongside the cable end.

In a further embodiment, the first ends of the cables are terminated into a plurality of connectors and the connectors are subsequently connected together by a housing.

The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only with reference to the accompanying drawings in which:-

Fig. I is a cross-sectional view of a quadrant of a cable used in a production process of the invention; Fig. 2(a), 2(b), and 2(c) are together a flow diagram illustrating the process in detail; and 30 Figs. 3(a) and 3(b) are cross-sectional and plan views respectively of ajig used in the process.

Referring to Fig. 1, the construction of the cables used for the process is illustrated. A 5 cable is indicated by the numeral 1 and it comprises an outer insulation jacket 2, a braid 3, a dielectric layer 4, an FEP insulation inner jacket 5, and a copper conductor core 6.

Such cable is cut as it is drawn from a cable reel and in this embodiment four lengths are cut for a single harness.

A first end of each of the cables is then prepared. In step 50 the outerjacket 2, the braid 3, and the inner jacket 4 are stripped. In step 51 the outer jacket and the braid are stripped and in step 52 the outer jacket alone is stripped to provide a stepped configuration as shown next to the step 52 in Fig. 2(a). This is perforTned using an automated stripping machine having a pair of rotating blades.

In step 53 the four cables are wrapped at two locations with heat shrink tape to hold the harness together during production, and also subsequently. In step 54 a drain wire 10 is soldered at a central location to the exposed braid 3 at each of the cable first ends. The drain wire 10 is wrapped in two turns around the braid 3 to ensure that there is excellent contact and both ends of the drain wire 10 are then trained towards the first end, generally parallel with the cable. This is illustrated next to step 54 in Fig. 2(b).

In step 55 the conductors 6 with insulation 5 and the drain wires 10 are terminated by insulation displacement to a connector 15. This is performed with an automated connectorising machine.

In step 56, a connector at the first end is completed by snap-fitting three parts of the connector 15 together. An outer housing 20 is then slid along the cables 1 and over the connectors 15 so that it holds the three connector parts together and the cables 1 are then wrapped at the housing 20 by a tie wrap 21. The housing 20 was previously slid onto the cables before termination of the first ends. Thus, at the first end of the four cables I there are two full connectors each comprising a housing 20 and a connector 15 as illustrated in the diagrams next to steps 56 and 57 in Fig 2(b). There may in other embodiments be additional full connectors, or only one.

In step 57, the other, second, end of each cable I is stripped to expose the conductor 6 at the extremity. The braid 3 and the dielectric 4 are also exposed. A ferrule 32 is slid over the cable. The conductor 6 is soldered to a centre pin 31 at a solder joint 30 and the braid 3 is then crimped onto a connector body 33 using the ferrule 32 as shown in the diagrams next to the steps 58 and 59 in Fig. 2(b).

An important aspect of the materials handling for the process are that a trolley 75 shown in Fig. 2(c) is used. This trolley has two uprights, namely a vertical upright and a tilted upright which have cross-bars for supporting harnesses. The harnesses are typically trained across the trolley between cross-bars on both uprights so that any desired number of harnesses may be transported or stored at a workstation at any one time and there is no danger of the ends of the cables being damaged.

In step 60, a j ig 3 5 shown in Figs. 3 (a) and 3 (b) is used to mount a connector plate 42 at the opposite, second, end of the cables 1. The jig 35 comprises a plate 36 having a pair of slots 37, each having opposed ledges 38. A pneumatic screwdriver head 41 is used for applying an outer socket 34 onto the connector body 33. The jig 35 also comprises a pair of e ection levers 39 which are urged by springs 40. The ends of the ejection levers form j parts of the side walls of the slots 37.

The plate 42 is placed on an upper surface of the jig. 35. The centre pin connectors comprising the centre pins 31 and the connector bodies 33 are mounted in the slots whereby they are supported by the ledges 38 and opposed flats are in contact with the edges of the ledges 38 so that they cannot rotate. The connectors 31 extend through apertures in the plate 42 in this position. Subsequently, it is an easy and simple operation for an operator to apply the outer sockets 3 3 in step 6 1.

Finally, in steps 62 and 63 the harness is labelled and tested. Testing involves use of a 5 test fixture 70 having sockets for receiving the connectors at the first ends and the connector block at the second end and applying continuity and voltage tests.

This provides a final hamess product 80, shown in Fig. 2(c).

It will be appreciated that the invention provides a production process which provides excellent quality in the manner in which the various cable ends are connected to the socket. If even a single layer of a single cable is connected to wrong part at a connector can cause the harness is faulty. It will also be appreciated that the invention provides excellent efficiency.

Also, the jig 35 provides for very accurate registration of the cable ends and centre pins with the mounting plate of the connector block and also allows this operation to be performed very quickly.

The invention is not limited to the embodiments described but may be varied in construction and detail within the scope of the claims.

Claims (8)

-6Claims

1. A process for producing a coaxial cable harness, the process comprising the steps of5 cutting at least two coaxial cables to pre-set lengths; stripping first end of the cables in a stepped configuration to successively expose a braid, a dielectric, and an inner jacket; 10 applying a drain wire to each exposed braid, at the first end; terminating the exposed conductors and drain wires into a connector at the first end; 15 stripping the opposite, second, ends of the cables to expose the conductor and soldering the exposed conductor to a coaxial centre pin and mounting a connector around the centre pin; and mounting a plate of a connector block onto an upper surface of a jig having a slot comprising ledges, supporting the connectors at the second ends on the ledges so that they extend through apertures of the plate, and screwing outer sockets onto the connectors while they are supported in the j i g.

2. A process as claimed in claim 1, wherein the jig comprises a plurality of side-by side slots aligned with apertures of the plate, and the upper surface is recessed.

3. A process as claimed in any of claims 1 or 2, wherein the connector block is removed by pressing a pair of opposed ejection levers pivotally connected to the jig and forming part of a side wall of each jig slot.

4. A process as claimed in any preceding claim, wherein the cables are stripped by an automatic tool having a pair of rotating blades.

5. A process as claimed in any preceding claim, wherein the drain wire is soldered to the braid and is wrapped around the braid whereby both ends of the drain wire extend alongside the cable end.

6. A process as claimed in any preceding claim, wherein the first ends of the cables are terminated into a plurality of connectors and the connectors are subsequently connected together by a housing.

7. A process substantially as described with reference to the drawings.

8. A coaxial cable harness whenever produced by a process as claimed in any preceding claim.