GB1571919A - Fixturesfor positioning cables and electrical connectors prior to their connection - Google Patents

Description

(54) IMPROVEMENTS IN FIXTURES FOR POSITIONING CABLES AND ELECTRICAL CONNECTORS PRIOR TO THEIR CONNECTION (71) We, AMP INCORPORATED, a corporation organised and existing under the laws of the State of New Jersey, United States of America, of Eisenhower Boulevard, Harrisburg, Pennsylvania, United States of America, 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-: The present invention relates to fixtures and in particular to a fixture for positioning accurately the conductors of a multiconductor flat flexible cable relative to a multi-contact electrica'-connector prior to the simultaneous connection of each contact to an individual conductor of the cable.

According to the present invention, a fixture for locating a multi-conductor flat flexible cable relative to a multi-contact electrical connector prior to the simultaneous connection of each contact to an individual conductor of the cable, each contact having a conductor receiving portion extending from a first surface of the electrical connector housing and including a pair of spaced contact arms defining between them a conductor receiving slot, comprises a connector support having a surface for engaging a second surface of the electrical connector housing which second surface is opposite the first surface, means for locating the electrical connector in a predetermined position in the fixture, a cable support including at least one surface for supporting the cable, means for locating the cable on the cable support surface so that a portion of the cable is in alignment with a connector when operatively positioned in the fixture and a clamping bar for clamping the cable to the cable support surface, the cable support being attached to the connector support but capable of limited movement towards and away from the said surface of the connector support, means for biasing the cable support away from the said surface of the connector support and a pressure plate positioned on the cable support for movement therewith adjacent the surface of the cable, when operatively positioned in the fixture, which cable surface is remote from the said surface of the connector support, the pressure plate having apertures each in alignment with a conductor receiving portion of a contact, the arrangement being such that on the application of pressure to the cable support, the cable will move relatively towards the first surface of the electrical connector housing and the conductor receiving portions of the conttacts will penetrate simultaneously the cable and establish electrical contact with the conductors.

An embodiment of the invention will now be desribed, by way of example, reference being made to the Figures of the accompanying diagrammatic drawings in which: Figure 1 is a transverse cross-section through a multi-conductor flat flexible cable; Figure 2 is a plan view of a multicontact electrical connector intended for connection to the cable of Figure 1; Figure 3 is a perspective view of a fixture for locating the flat flexible cable of Figure 1 relative to the electrical connector of Figure 2; Figure 4 is a cross-section on the line 4-4 of Figure 3; Figure 5 is a perspective view of the fixture of Figure 3 and a cable loaded but not clamped within the fixture; Figure 6 is a perspective view similar to Figure 5 but showing the cable clamped in the fixture; Figure 7 is a perspective view of the fixture of Figure 1 which is clamped to a cable intermediate its ends; Figure 8 is a fragmentary detail of the fixture of Figure 3; Figure 9 is a fragmentary cross-section of a modified detail of the fixture of Figure 3; Figure 10 is a diagrammatic view of the modified fixture of Figure 3 with a cable loaded in the fixture; Figure 11 is a view similar to Figure 10 but showing the cable clamped in the fixture; and Figure 12 is a fragmentary cross-section similar to Figure 9 but illustrating a further modification of the detail.

As shown in Figure 1, a multi-conductor flat flexible cable 2 comprises a plurality of spaced, parallel conductors 4 embedded in insulation 6. The insulation between adjacent conductors 4 is in the form of a thin land 8. The conductors 4 are spaced apart by a nominal uniform pitch distance d and there is usually a manufacturing tolerance t on the dimension d. For example, where the nominal pitch distance d equals 0.050 inches the tolerance t is frequently +0.003 inches. From time to time, a given length of cable 2 may have certain conductors 4 which are spaced apart a distance which falls outside the tolerance as a result of faulty manufacture or handling subsequent to manufacture.

A multi-contact electrical connector 12 shown in Figure 2 is intended for connection to the cable 2. The connector 12 includes a plurality of spaced contacts 14 each having a conductor receiving portion 15 extending from a surface 16 of an insulating housing 18. Each contact includes a pair of spaced contact arms defining between them a conductor receiving slot and is connected to an individual conductor 4 of the cable 2 by moving the cable 2 relatively towards the surface 16 so that the portions 15 penetrate the cable 2 and establish electrical contact with individual conductors 4. The spacing between adjacent portions 15 is d. The housing 18 includes two opposed laterally extending flanges 17.

The electrical connector includes a cover 100 which is releasably attached to the housing 18 by latching arms 102. Throughholes 104 are provided in the cover 100, which holes 104 each receive a conductor receiving portion 15 of an individual contact 14.

Referring now to Figures 3 to 6, a fixture 22 for locating the flat flexible cable 2 relative to the electrical connector 12 prior to the connection of the connector 12 to the cable 2, includes a connector support 24 and a cable support 26. The connector support 24 includes a base plate 28 having a surface 30. At each end of the surface 30 is a locating boss 34. Each boss 34 has a laterally extending ear 36.

The cable support 26 includes a generally rectangular frame having spaced parallel slide rails 40 connected to each other by end blocks, 42,43. The opposed surfaces of the end blocks 42,43 have recesses 46 and the ears 36 each extend into a recess 46 so that the connector support 24 and the cable support are attached to each other although limited movement of the cable support 24 towards and away from the surface 30 is possible since the recesses 46 are oversized relative to the thickness of the ears 36. The cable support 26 is normally biased upwardly (as shown) to the limit of its travel by springs 44 which extend into respective recesses in a block 42,43 and the upper surface of the base plate 28.

Each side rail 40 has a laterally outwardly extending flange 48,49 at its upper (as shown) end, the upper fluted surfaces 50,51 of these flanges constituting cable supporting surfaces when the connector is intended to be installed on a cable 2 intermediate its ends. Only the surface 50 is used as a cable supporting surface when the connector 12 is installed on the end of the cable 2 as will be explained below.

The cable supporting surface 50 has parallel shallow flutes which are dimensioned to receive the cable 2, the spacing between the deepest portions of adjacent flutes being the same as the spacing between adjacent conductors 4 in the cable 2, that is d. Opposed shoulders 52,54 are provided at the ends of the support surface 50 so that the side edges of the cable 2 can be located against these shoulders when the cable 2 has a width which is the same as the width of the support surface 50. When a connector 12 is being connected to a narrower cable one edge of the cable is positioned against shoulder 52 and the cable is otherwise aligned by the flutes in the surface 50.

The end block 43 has an upwardly facing surface 56 (Figure 4) which supports one of the flanges 17 of the connector housing 18 when the cable support 26 is biased upwardly (as shown) by the springs 44 away from the surface 30 of the connector support 24. The other flange 17 is supported on the upper surface of a support plate 58 which extends across the gap between the side rails 40. The support plate 58 is L-shaped having an arm 60 which is received in a channel 62 in a surface 90 of a side rail 40, the side edge of the plate 58 being received in a corresponding channel in the opposite side rail 40. The position of the support plate 58 is adjustable leftwardly as seen in Figure 4 towards the end block 43 so that a smaller size connector can be accommodated in the fixture 22 and its flange 17 will be supported on the surface 56 and the upper surface of support blade 58. A locking pin (not shown) can be provided to lock the support plate 58 in any desired position. The surface 90 acts as a stop for the end of a cable 2 as will be explained.

The cable 2 is clamped by clamping bars 66,67 which differ from each other in certain respects. The clamping bar 66 is used when a connector 12 is being installed on the end of a cable 2 and will be described first.

The clamping bar 66 is pivotally mounted on a pin 70 extending from a pivot block 68. This permits the clamping bar 66 to be moved from the position shown in Figure 5 to that shown in Figure 6. The pivot block 68 is mounted for pivotal movement on a pin 72 which extends through the flange 48 and into the end block 43. This permits the clamping bar 66 to be moved upwardly from the position of Figure 6 to the position shown in Figure 3.

Referring also to Figure 8, at its opposite end, the clamping bar 66 has a round pin 78 which is provided adjacent its end with flats. The pin 78 is rotable relative to the bar 66 and is received within a key-hole slot 82 in a plate 81 extending from the end block 42.

An additional pivot pin 84 extends from the free end of the clamping bar 66 and a handle pin 85 extends laterally from a cylindrical latching bush 86. The latching bush 86 is a snug fit in a recess 87 between the righthand end (as shown) of the flange 48 and the plate 81.

The pin 84 is received within a slot 83 in the plate 81. The clamping bar 66 is formed along a substantial part of its length with a recess 74.

Clamping bar 67 is of more simple construciton than clamping bar 66 in that a pivot block 69 is integral with the clamping bar 67 and pivots about the pin 72. Thus the clamping bar 67 can be moved upwardly from the position shown in Figure 6 to the position shown in Figure 3. A fixed latching bush 88 is provided on the end of clamping bar 67, but it is not necessary that the bush 88 be pivotally mounted as is the bush 86.

A pin 89 is fixed to the bush 88 and is received in a slot in a plate extending from the end block 42.

Each end block 42,43 has, extending from an upper (as shown) surface a locating pin 98. A rectangular pressure plate 94 is locatable on the pins 98. The pressure plate 94 has through apertures 95.

In use when it is desired to connect an electrical connector 12 to the end of a cable 2, the electrical connector 12 less the cover 100 is placed in the connector support 24 and located between the bosses 34 with its flanges 17 supported on the surface 56 of the end block 43 and on the upper surface of the support plate 58. The conductor receiving portions 15 of the contacts 14 will extend upwardly (as shown). Next the clamping bar 66 is moved to the position shown in Figure 5. The cable 2 is inserted through the recess 74 until the end of the cable engages the stop surface 90 on the rear (as shown) side rail 40. The clamping bar 66 is then pivoted about pin 70 to the position shown in Figure 6, to clamp the cable 2 to the surface 50 of the flange 48.

The pressure plate 94 is then located on the pins 98, the conductor receiving portion 15 of the contacts each being aligned with a through aperture 95.

Pressure is then applied to the pressure plate 94 and to the clamping bar 66, for example, by a hand compression tool as described and claimed in our co-pending application No.6615/77 (Serial No.1 569 351) so that the entire cable support 26 is moved downwardly (as shown) relative to the electrical connector 12 against the bias of springs 44. The surface 30 of the connector support 24 will engage the surface of the connector housing 18 opposite the surface 16 thereby causing the conductor receiving portions 15 of the contacts to pierce the insulation 6 of the cable 2 and electrically engage the conductors 4. The conductor receiving portions 15 are each received in a through aperture 95 of the pressure plate 94.

After the connection of the connector 12 to the cable 2, the pressure plate 94 is removed and the clamping bar 66 moved to the position of Figure 4 to release the cable with its assembled electrical connector.

The clamping bar 67 remains in its lowered or closed position (Figures 5 and 6) when a connector 12 is being installed on the end of a cable 2 and as explained the surface 90 and also the edge of clamping bar 67 serve as a stop for the end of the cable 2. Clamping bar 67 is used only when the connector 12 is installed on an intermediate portion of the cable 2 as shown in Figure 7.

When it is desired to install a connector 12 on an intermediate portion of the cable 2, both of the clamping bars 66,67 are swung upwardly and the intermediate portion of the cable 2 is positioned on the surfaces 50,51 so that it extends across the connector 12 which is placed in the connector support 24. Thereafter, the clamping bars 66,67 are swung downwardly, so that the cable 2 is clamped by both clamping bars 66,67. The pressure plate 94 is positioned on the pins 98, and pressure is applied to the pressure plate 94 and also the upper surfaces of the clamping bars.

The cable support 26 is thereby moved relatively downwardly so that the conductor receiving portions 15 of the contacts 14 pierce the cable.

The fixture 22 may be modified by the addition of a tension member 120 which forms an integral part of the fixture 22 (see Figures 4 and 7). The tension member 120 is of particular utility when the fixture 22 is used with the compression handtool described and claimed in our co-pending application No.6615/77.

Under some circumstances, it may prove feasible to use the cover 100 as a pressure plate. If this procedure is followed, the cover 100 rather than the pressure plate 94, is positioned in the fixture 22 prior to the step of applying pressure on the fixture to move the cable 2 towards the connector 12.

When this procedure is followed, the conductors 4 of the cable 2 are connected to the contacts 14 and the cover 100 is assembled to the housing 18 in a single step.

The fixture 22 has utility for locating a multi-contact electrical connector 12 relative to a multi-conductor flat flexible cable especially when used with the compression handtool of our co-pending application No.6615/77 (Serial No.1 569 351).

However, from time to time as previously explained, a given length of cable 2 may have certain conductors 4 which are spaced apart a distance which falls outside manufacturing tolerances.

When this occurs, it is an advantage to use a fixture 22 which has been modified as explained below.

As mentioned previously, the surfaces 50,51 are fluted as are the associated opposed surfaces 71,73 of the clamping bars 66,67.

The geometry of the flutes in the opposed surfaces 50,71 of the flange 48 and the clamping bar 66 is shown in Figure 9. The surface 71 has side-by-side flutes 106,108 which extend thereacross and which have a radius of curvature which is substantially greater than the diameter of the insulation 6 as will be described more fully below. The flutes 106 are recessed into the surface 71 relatively more deeply than the flutes 108. The surface 50 has recessed flutes 112 which are opposed to the relatively shallow flutes 108 of the surface 71 and the surface 50 has relatively shallow flutes 114 which are opposed to the recessed flutes 106 of the surface 71.

When the two surfaces are positioned against each other as shown in Figure 9, the geometric centres of the opposed pairs of flutes, as viewed in cross-section, define a zig-zag path as is apparent from Figure 9.

The spacing between the centre lines of adjacent pairs of flutes 106,108 and 112,114 is equal to the nominal spacing d between adjacent conductors 4 of the cable 2. This centre-to-centre spacing between adjacent centres is measured between the vertically extending centre lines of the flutes as seen in Figure 9 rather than along the diagonal lines which would connect the centres. It should be noted that the cavities defined by opposed pairs of flutes 106,114 and 108,112 communicate with adjacent cavities through constricted sections which are defined by round surfaces 110,111. The land material 8 of the cable 2 is confined in these constricted sections when the cable 2 is clamped between the surfaces.

Figures 10 and 11 illustrate the manner in which imperfectly or unevenly spaced conductors 4 in a cable 2 are repositioned in the fixture 22 so that the conductors will be in alignment with the contacts 14 in the connector 12 mounted in the fixture 22.

Figure 10 shows a cable 2 which has several of its conductors offset from the positions they would occupy if the spacing between adjacent conductors were constant and uniform in the cable. Some of the conductors on the right hand portion of the cable are displaced so that they are offset from the centre lines of the flutes in the surface 50 by significant distances. This view also shows the locations of the conductor-receiving portions 15 of the contacts 14 in the background and it will be noted that each contact is precisely aligned with the centre line of one of the flutes although the conductors in some instances are offset from the centre lines of the conductor-receiving portions 15.

When a connector is being connected to the cable 2, the connector is first positioned in the fixture 22 and the cable 2 is positioned on the surface 50 as shown in Figure 10. The clamping bar 66 is then lowered from the position of Figure 10 to the position of Figure 11 and during such lowering of the bar 66, the opposed curved surfaces of the flutes will engage those conductors which are offset from their proper centre lines and displace them laterally until they are properly centred or aligned with the conductor-receiving portions 15 of the contacts 14 in the connector 12. While the conductors 4 in the cable 2 as shown in Figure 11 follow a zig-zag pattern as viewed in cross-section, the axes of the individual conductors 4 are nonetheless in precise alignment with the conductorreceiving portions 15 of the contacts 14.

When the conductors 4 in the cable 2 are repositioned as shown in Figure 11 by the opposed surfaces 50,71 the portions of the conductors 4 which are adjacent to these surfaces and which are above the conductor-receiving portions 15 of the contacts 14 will also be repositioned. The operator can then complete the process of installing the connector on the cable by placing the pressure plate 94 in the fixture 22 and applying a normal force against the pressure plate.

Some specific dimensions are presented below to illustrate the cable dimensions which can be accommodated by the modified fixture 22. With a cable 2 of the type shown in Figure 1 having a conductor pitch distance of 0.050 inches and a tolerance range of +0.003 inches, good results are obtained if the radii of curvature of all the flutes 106, 108, 112, 114 is about 0.028 inches, in other words, slightly greater than d The centres of 2 curvature of the flutes 108 on the surface 71 are offset downwardly as viewed in Figure 9 by a distance of 0.010 inches, about three times the tolerance limit, t, relative to the centre of curvature of the flutes 106. The flutes in the surface 50 are offset by the same amount, that is, the centres of curvature of the flutes 114 are offset upwardly by a distance of 0.010 inches from the centres of curvature of the flutes 112. It has been found that when these dimensions are provided on the surfaces 50,71 the conductors 4 will be brought into alignment and repositioned on precise centres even if the spacing between adjacent conductors is as much as 0.060 inches or as little as 0.040 inches; in other words, if the cable dimensions depart from the specifications by about three times the tolerance limits (+0.003 inches) of the specification. If the nominal spacing between adjacent conductors is more or less than 0.050 inches, the dimensions and radii would be different from those discussed above but the same general relationships should be maintained.

Figure 12 shows an alternative embodiment in which the centres of curvature of the flutes in each of the surfaces are offset by a substantially greater amount than that shown in Figure 9. Specifically, the offset in Figure 12 is such that when the surfaces 50,71 are against each other, the diagonal line distance between adjacent centre lines or the centre lines of adjacent opposed pairs of flutes is 0.06 inches although the horizontal spacing remains at 0.050 inches between adjacent centre lines. This embodiment is intended for use where the cable has a nominal spacing between adjacent conductors of 0.050 inches and the tolerance range t is +0.010 inches. In practice, if the conductors are spaced-apart by as much as 0.070 inches or as little as 0.030 inches, the conductors will be brought into alignment when the cable is clamped in the fixture.

It is emphasized that the dimensions given above by way of example can be departed from under some circumstances.

Satisfactory results may sometimes be obtained if the dimensions are departed from but the accuracy of the location effect may be reduced.

The modified clamping bar 67 can be used under a variety of circumstances and it is described on the fixture 22 only by way of example. The offset flute construction for aligning conductors can also be provided on a single surface of a member and will serve to bring misaligned conductors into proper alignment.

The modified clamping bar 67 can, for example be considered as a member forming part of a fixture for positioning accurately the conductors of a multiconductor flat flexible cable in a predetermined array. The fixture includes the member which has a cable engaging surface adapted to extend across the width of the cable. Side-by-side parallel flutes extend across the surface, the flutes being spaced apart on centre lines having a predetermined pitch distance. Each flute has in cross-section a centre of curvature and the centres of curvature of alternate flutes are offset with respect to the centres of curvature of the remaining flutes. The arrangement of the flutes is such that when the cable and the surface are pressed together the conductors of the cable assume a zig-zag array as seen in transverse cross-section.

As previously explained, the cover 100 can be used as a pressure plate and the surface of the cover 100 facing the surface 16 of the connector housing 18 can be formed with flutes of the type 106,108 formed in the surface 71 of the clamping bar 66.

Fixtures as described above are also described, and some are claimed, in Application No.33227/78 (Serial No.1 571 920) which was divided from this application.

WHAT WE CLAIM IS: 1. A fixture for locating a multiconductor flat flexible cable relative to a multi-contact electrical connector prior to

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

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. with the conductor-receiving portions 15 of the contacts 14 in the connector 12. While the conductors 4 in the cable 2 as shown in Figure 11 follow a zig-zag pattern as viewed in cross-section, the axes of the individual conductors 4 are nonetheless in precise alignment with the conductorreceiving portions 15 of the contacts 14. When the conductors 4 in the cable 2 are repositioned as shown in Figure 11 by the opposed surfaces 50,71 the portions of the conductors 4 which are adjacent to these surfaces and which are above the conductor-receiving portions 15 of the contacts 14 will also be repositioned. The operator can then complete the process of installing the connector on the cable by placing the pressure plate 94 in the fixture 22 and applying a normal force against the pressure plate. Some specific dimensions are presented below to illustrate the cable dimensions which can be accommodated by the modified fixture 22. With a cable 2 of the type shown in Figure 1 having a conductor pitch distance of 0.050 inches and a tolerance range of +0.003 inches, good results are obtained if the radii of curvature of all the flutes 106, 108, 112, 114 is about 0.028 inches, in other words, slightly greater than d The centres of 2 curvature of the flutes 108 on the surface 71 are offset downwardly as viewed in Figure 9 by a distance of 0.010 inches, about three times the tolerance limit, t, relative to the centre of curvature of the flutes 106. The flutes in the surface 50 are offset by the same amount, that is, the centres of curvature of the flutes 114 are offset upwardly by a distance of 0.010 inches from the centres of curvature of the flutes 112. It has been found that when these dimensions are provided on the surfaces 50,71 the conductors 4 will be brought into alignment and repositioned on precise centres even if the spacing between adjacent conductors is as much as 0.060 inches or as little as 0.040 inches; in other words, if the cable dimensions depart from the specifications by about three times the tolerance limits (+0.003 inches) of the specification. If the nominal spacing between adjacent conductors is more or less than 0.050 inches, the dimensions and radii would be different from those discussed above but the same general relationships should be maintained. Figure 12 shows an alternative embodiment in which the centres of curvature of the flutes in each of the surfaces are offset by a substantially greater amount than that shown in Figure 9. Specifically, the offset in Figure 12 is such that when the surfaces 50,71 are against each other, the diagonal line distance between adjacent centre lines or the centre lines of adjacent opposed pairs of flutes is 0.06 inches although the horizontal spacing remains at 0.050 inches between adjacent centre lines. This embodiment is intended for use where the cable has a nominal spacing between adjacent conductors of 0.050 inches and the tolerance range t is +0.010 inches. In practice, if the conductors are spaced-apart by as much as 0.070 inches or as little as 0.030 inches, the conductors will be brought into alignment when the cable is clamped in the fixture. It is emphasized that the dimensions given above by way of example can be departed from under some circumstances. Satisfactory results may sometimes be obtained if the dimensions are departed from but the accuracy of the location effect may be reduced. The modified clamping bar 67 can be used under a variety of circumstances and it is described on the fixture 22 only by way of example. The offset flute construction for aligning conductors can also be provided on a single surface of a member and will serve to bring misaligned conductors into proper alignment. The modified clamping bar 67 can, for example be considered as a member forming part of a fixture for positioning accurately the conductors of a multiconductor flat flexible cable in a predetermined array. The fixture includes the member which has a cable engaging surface adapted to extend across the width of the cable. Side-by-side parallel flutes extend across the surface, the flutes being spaced apart on centre lines having a predetermined pitch distance. Each flute has in cross-section a centre of curvature and the centres of curvature of alternate flutes are offset with respect to the centres of curvature of the remaining flutes. The arrangement of the flutes is such that when the cable and the surface are pressed together the conductors of the cable assume a zig-zag array as seen in transverse cross-section. As previously explained, the cover 100 can be used as a pressure plate and the surface of the cover 100 facing the surface 16 of the connector housing 18 can be formed with flutes of the type 106,108 formed in the surface 71 of the clamping bar 66. Fixtures as described above are also described, and some are claimed, in Application No.33227/78 (Serial No.1 571 920) which was divided from this application. WHAT WE CLAIM IS:

1. A fixture for locating a multiconductor flat flexible cable relative to a multi-contact electrical connector prior to

the simultaneous connection of each contact to an individual conductor of the cable, each contact having a conductor receiving portion extending from a first surface of the electrical connector housing and including a pair of spaced contact arms defining between them a conductor receiving slot, comprising a connector support having a surface for engaging a second surface of the electrical connector housing which second surface is opposite the first surface, means for locating the electrical connector in a predetermined position in the fixture, a cable support including at least one surface for supporting the cable, means for locating the cable on the cable support surface so that a portion of the cable is in alignment with a connector when operatively positioned in the fixture and a clamping bar for clamping the cable to the support surface, the cable support being attached to the connector support but capable of limited movement towards and away from the said surface of the connector support, means for biasing the cable support away from the said surface of the connector support and a pressure plate positioned on the cable support for movement therewith adjacent a surface of the cable, when operatively positioned in the fixture, which surface is remote from the said surface of the connector support, the pressure plate having apertures each in alignment with a conductor receiving portion of a contact, the arrangement being such that on the application of pressure to the cable support the cable will move relatively towards the first surface of the electrical connector housing and the conductor receiving portions of the contacts will penetrate simultaneously the cable and establish electrical contact with the conductors.

2. A fixture as claimed in claim 1, in which the means for locating the electrical connector is a pair of spaced bosses each extending in the same direction from the said surface of the connector support, each boss having a laterally extending ear, the cable support including a rectangular frame having spaced, parallel side rails connected to each other by end blocks, the opposed surfaces of the end blocks each having a recess adapted to receive an ear of a boss, each recess being oversized relative to its associated ear to permit movement of the cable support towards and away from the said surface of the connector support.

3. A fixture as claimed in claim 2, in which each side rail has a laterally outwardly extending flange, the upper surfaces of which flanges constitute cable support surfaces, individual clamping bar being associated with each cable support surface, the two cable support surfaces being coplanar, parallel and spaced apart, the said surface of the connector support being arranged in alignment with the space between the two cable support surfaces.

4. A fixture as claimed in any one of claims 1 to 3, in which the or each cable support surface and a surface of the or each associated clamping bar opposed to the cable support surface are each provided with side-by-side parallel flutes extending across the surface, the flutes being spaced apart on centre lines which extend normally of the surface by a predetermined pitch distance, each flute having a centre of curvature, the centres of curvature of alternate flutes being offset with respect to the centres of curvature of the remaining flutes, such that when the cable is sandwiched between opposed surfaces the conductors of the cable assume a zig-zag array as seen in transverse cross-section.

5. A fixture as claimed in any one of claims 2 to 4, in which the pressure block is releasably located on the cable support by two pins, each pin extending from an end block.

6. A fixture for locating a multiconductor flat, flexible cable relative to a multi-contact electrical connector, constructed and arranged substantially as hereinbefore described, with reference to and as illustrated in the drawings.