Electrical Connector Housing

Abstract

An electrical connector housing comprising a tubular body of resilient insulation material internally formed with an integral detent presenting a forward facing shoulder and with a stop for limiting forward movement of an inserted contact receptacle, at least a portion of the body being of generally rectangular cross-section, is characterized according to the present invention in that, the detent extends across a corner of the portion of rectangular cross-section, and presents a forward facing shoulder of triangular cross-section and a rear surface inclined rearwardly, outwardly and between the adjacent walls of the portion of rectangular cross-section.

Description

This invention concerns an electrical connector housing of the kind adapted to contain a contact receptacle for mating with a contact tab. Housings of this kind are generally referred to as pods and are adapted for manual application to an individual contact receptacle after the receptacle has been connected to a wire. Generally such housings comprise a tubular body molded from plastics material such as polyethlene in a generally rectangular cross-section. The body is formed internally with a forward facing detent shoulder arranged so that on insertion of the contact receptacle through the rear end of the body, the detent shoulder is deflected by resilient deformation of the detent, and/or of the body to admit passage of the receptacle past the detent until the detent shoulder can relax into its normal position and engage behind a rear facing shoulder of the contact receptacle to resist withdrawal.

Several different product designs have been developed but generally two difficulties arise. Firstly, in order to allow for facility of insertion of the contact receptacle with relatively low insertion forces, an easily flexible housing is required, and it is difficult to obtain this without adverse effect on the withdrawal force. Secondly, the first difficulty often results in the use of an easily deformed material for the housing which may offer insufficient protection to the contact receptacle.

It is an object of the present invention to provide a connector housing of the kind in question with which relatively higher pull-out or withdrawal forces can be obtained with an acceptably low insertion force and which can be made for example of NYLON.

An electrical connector housing comprising a tubular body of resilient insulation material internally formed with an integral detent presenting a forward facing shoulder and with a stop for limiting forward movement of an inserted contact receptacle at least a portion of the body being of generally rectangular cross-section, it is characterized according to the present invention in that, the detent extends across a corner of the portion of rectangular cross-section, and presents a forward facing shoulder of triangular cross-section and a rear surface inclined rearwardly outwardly and between the adjacent walls of the portion of rectangular cross-section.

In operation the rear surface of the detent exerts a camming action on insertion of a contact receptacle to engage the rear surface, and a force is developed diagonally of the body cross-section tending to deform the cross-section into a parallelepiped with minimal material deformation. The rectangular section is less stiff to such deformation than to strain in a direction perpendicular to either pair of walls, and as a result stiffer or harder insulating materials can be used. Furthermore, pull-out forces on the contact receptacle are applied to the forward facing shoulder and are essentially axial of the housing. There is substantially no reaction force developed along the cross-section diagonal to move the detent in a release direction and substantially improved pull-out resistance is obtained.

Preferably, a wall of the body remote from the corner formed with the detent, and defining a longer side of the rectangular cross-section, is formed intermediate its width with a pair of spaced longitudinal, internal ribs. In operation the diagonal reaction force of the detent drives the contact receptacle against the ribs tending to flex that wall outwardly in bowed manner.

In another embodiment, the wall of the body remote from the detent latch and defining a longer side of the rectangular cross-section is formed at the corners of the cross-section with a pair of longitudinally extending ribs. The rib closer to the detent latch extends rearwardly from the forward end of the body and terminates forwardly of the detent shoulder in a ramp inclined rearwardly away from the detent latch. The other rib which is diagonally opposite to the detent extends substantially throughout the length of the body.

In operation, on initial insertion of a contact receptacle, the base of the receptacle at one side engages the longer rib and is elevated above the floor of the body whereas the receptacle at the other side rides along the floor so that in cross-section the receptacle is tilted in relation to the floor laterally of the body. The lower side of the receptacle passes beneath the detent latch before engaging the ramp of the shorter rib which then elevates that side of the receptacle to engage the detent and flex the body cross-section. As the contact receptacle is fully inserted, it reaches a position where the latch detent relaxes behind the receptacle portion which is elevated by the shorter rib to a position generally parallel with the floor.

This has the advantage that on initial insertion, tendency for the leading edge of the contact receptacle to cut into the leading lower edge of the detent is guarded against.

The invention will now be described, by way of example, with reference to the accompanying partly diagrammatic drawings, in which:

FIG. 1 is a perspective view of an insulating pod according to a first embodiment containing a tab receptacle secured to a wire;

FIG. 2 is a sectional view of the housing of FIG. 1 looking upwards into the roof with the receptacle removed;

FIG. 3 is a sectional side elevation on the line 3--3 of FIG. 2 with the receptacle in position;

FIG. 4 is a front end view of the assembly of FIG. 1;

FIG. 5 is a partially exploded perspective view of a second embodiment of the connector housing looking into the rear end;

FIG. 6 is a transverse section taken on line 6--6 of FIG. 7 of an intermediate portion of the housing with a receptacle partially inserted;

FIG. 7 is a sectional side elevation of the housing of FIG. 5 with a receptacle partially inserted and taken on line 7--7 of FIG. 6;

FIG. 8 is a view corresponding to that of FIG. 7 but with the receptacle further inserted; and

FIG. 9 is a further view corresponding to FIG. 7 but with the receptacle fully inserted and retained in the pod.

The assembly of FIG. 1, as seen more clearly in FIG. 3 comprises a housing pod 1 containing an electrical contact receptacle 2 secured to an insulated wire 3 which extends from the rear, right-hand end of the housing pod 1. The housing 1 is molded of resilient insulating material, e.g. NYLON, in one piece and is of tubular form, having a generally rectangular cross-section as seen in FIG. 4. The housing 1 is of uniform width throughout its length but, as seen in side elevation, has a forward left-hand portion 4 of reduced height compared with a rearward right-hand portion 5. A transition portion 6 slopes forwardly and downwardly from the upper surface of portion 5 to that of portion 4. The wall thickness of the housing is substantially uniform throughout so that the internal configuration substantially conforms to that described above to provide a flat floor 7, a stepped roof 8 and opposite flat sides 9, 10.

The rear end of the housing is enlarged to receive the wire 3 extending from the tab receptacle 2 disposed in the forward reduced portion of the housing. This facilitates insertion of the receptacle and also accommodates wires of enlarged diameter without impediment.

The forward end 11 of the housing is constricted to define an insertion stop for the receptacle. A lip 12 extends across the width of the forward end 11 and projects upwardly from the floor 7. The lip 12 is formed centrally with a recess 13 for accommodating a carrier-strip portion of the receptacle 2 which in practice often occurs due to imperfect shearing of a receptacle from a strip of terminals during manufacture.

A rectangular flap 14 projects downwardly from the roof at the forward end 11 and extends across approximately half of the width of the body 1 from the side wall 10, and through approximately half of the height of the body portion 4. This flap 14 serves partially to mask the forward end, to guide an inserted tab into the appropriate tab-receiving portion of the receptacle and prevent engagement of the tab between the receptacle 2 and the roof 8 of the housing. A rib 15 extends axially of the housing portion 4 along the roof 8 from the flap 10 and centrally of the housing width. This rib serves to center the receptacle 2 widthwise of the housing by engaging between the spring rolls 16 of the receptacle as seen in FIG. 4. The rib 15 terminates forwardly of the transition 6.

The floor 7 of the housing is formed internally with a pair of ribs 17 extending longitudinally and spaced apart equally from the sides 9, 10 of the housing. The ribs project upwardly from the floor 7 through less height than the forward lip 12 and extend rearwardly from the lip, to a position opposite the transition 6 where they taper rearwardly in height to merge with the floor at a ramp 18.

The housing is formed internally with a latch detent 19 presenting a forward facing shoulder surface 20 of triangular form as seen in FIG. 4 at the corner between the side 9 and the roof 8 and forwards of the transition 6. A flat ramp surface 21 extends rearwardly from the hypotenuse edge 22 of the shoulder 20 at a rearward and outward inclination in relation to the longitudinal axis or insertion direction of the housing so that the surface 21 projects from the roof 8 and the side wall 9 rearwardly of the shoulder 20. The ramp surface 21 terminates approximately midway between the front and rear of the transition surface 6.

The tab receptacle 2, which is of well-known form comprises the forward receptacle portion 2 and a rearward crimping section 23 securing the receptacle portion for the conductive core and to the insulation of the wire 3. The receptacle portion is of generally channel form having a base engaging the ribs 17 at the floor of the housing. Sides of the receptacle 2 are folded in to provide the spring rolls 16, free edges of which are opposed to the base and disposed either side of the rib 15.

In assembling the housing 1 to the terminated wire 3, the receptacle portion 2 is manually inserted in the enlarged rear end of the housing and moved forwards to engage the leading end of the base with the floor ramps 18 and the leading end of one of the spring rolls 16 with the latch ramp surface 19. Further insertion of the receptacle produces a force on the surface 19 generally diagonally of the housing rectangular cross-section to flex the cross-section into generally parallelepiped form. At the same time a flexure is applied to the pg,8 floor 7 through the ribs 17. The resulting resilient distortion of the housing allows forward passage of the receptacle past the hypotenuse edge 22 of the latch shoulder 20. When the rear end of the spring roll 16 moves forwards of the edge 22, the housing relaxes and the shoulder 20 latches behind the rear of the spring roll as shown in FIG. 3.

Pull-out forces on the wire 3 urge the receptacle rear against the shoulder 20 with an essentially axial force which develops substantially no reaction in the diagonal direction necessary to flex the housing in the same manner as during insertion. As a result the receptacle is securely retained.

In the embodiment of FIGS. 5 to 9 like reference numerals will be used to refer to similar parts in the embodiment of FIGS. 1 to 4 and the following description will essentially be directed to the different features.

The latch detent between the forward shoulder surface 20 and the rear ramp surface 21 is formed with a flat shoulder surface 32 extending from the hypotenuse edge 22 of shoulder 21, parallel to the housing longitudinal axis, or insertion direction. The floor 7 is formed internally at the side 10 with a longitudinal rib 33 extending throughout the housing length. At the opposite side 9 the floor 7 is formed with a rib 34 of corresponding form but extending through only part of the housing length rearwardly from the forward end and terminating forwardly of the latch detent in a ramp 35 tapering to the housing floor 7.

In assembling the housing of FIG. 5 to a terminated wire, as shown in FIGS. 6 to 9, initial insertion engages one side of the receptacle base with the upper surface of rib 33 to elevate that side above the floor 7, but the other side of the receptacle engages the floor 7. As a result as seen in FIG. 6, the receptacle 2 is tilted widthwise in relation to the base 7. Further insertion causes the lower side of the receptacle to pass below the latch surface 32 as seen in FIGS. 6 and 7, without any strain being imposed on the housing 1 until the leading end of the receptacle base engages the ramp 35. The ramp 35 serves to elevate the lower side of the receptacle, as shown in FIG. 8, on further insertion to impose a force on the latch surface 32 to effect resilient distortion of the housing generally in the manner described in relation to the first embodiment. Finally the receptacle 2 reaches the position of FIG. 9 where the rear of the receptacle portion 2 clears the shoulder 20 so that the housing relaxes and the shoulder engages behind the receptacle spring roll at that side. In this condition, the ribs 33 and 34 stand the receptacle base away from the floor.

An advantage of the second embodiment is that distortion forces are applied to the surface 32 rather than the surface 21, and are more exactly in the direction of desired movement of the latch. Further, the distortion forces are not generated by engagement of the leading edge of the receptacle with the surface 21, but by engagement of the upper surface 36 of the spring roll with the generally parallel surface 32. There is a reduced risk of the receptacle cutting into the material of the latch which might cause damage or high insertion forces.

In a further embodiment, the latch ramp surface decreases progressively in height as it extends rearwardly to merge smoothly with the junction of the adjacent wall and roof of the housing adjacent the rear end of the housing and the longitudinal rib formed at the opposite corner extends from the front of the housing to a location opposite the shoulder and then is of progressively decreasing height until it merges smoothly with the base below the transition portion.

Claims

What is claimed is:

1. An electrical connector housing comprising a tubular body of resilient insulating material, at least a portion of the body being of generally rectangular transverse cross-section having four side walls; a rigid latching detent being integrally formed with the body to extend across a corner of the portion of rectangular cross-section between a first two adjacent side walls presenting a forward facing shoulder of triangular transverse cross-section having an hypotenuse facing the remaining two adjacent side walls and a rear surface inclined rearwardly and outwardly between said first two adjacent walls of the portion of rectangular cross-section; and a stop integrally formed with the body for limiting forward movement of an inserted contact receptacle, whereby insertion of a contact receptacle causes said portion of rectangular cross-section to be deformed into a parallelepiped.

2. A housing as claimed in claim 1, in which a wall of the housing remote from the corner formed with the detent and defining a longer side of the rectangular cross-section is formed internally with a pair of spaced ribs extending longitudinally of the housing.

3. A housing as claimed in claim 2, in which one of the ribs extends along a corner of the cross-section, diagonally opposite the detent and the other extends along the other corner, the one rib extending substantially throughout the housing length and the other rib extending rearwardly from the forward end and terminating forwardly of the detent shoulder in a ramp sloping rearwardly to the housing wall formed with the two ribs.

4. A housing as claimed in claim 3, in which the junction between the detent forward shoulder and the rear surface is formed as a flat surface extending parallel with the housing length.

5. A housing as claimed in claim 1, in which the housing is of uniform major width throughout its length, a rear portion having an enlarged height in relation to a forward portion and a transition surface extending between the forward and rearward portions at one side of the housing, the detent being formed internally of the housing at the junction between the transition and the forward portion, the forward shoulder being disposed forward of the transition surface.