WO2008105676A1

WO2008105676A1 - Lock ring system for an electrical connector or appliance

Info

Publication number: WO2008105676A1
Application number: PCT/NZ2008/000037
Authority: WO
Inventors: Ian Wickens
Original assignee: Schneider Electric New Zealand Limited
Priority date: 2007-02-27
Filing date: 2008-02-27
Publication date: 2008-09-04
Also published as: AU2007203020A1; NZ553514A; AU2007203020B2

Abstract

An electrical connector or appliance comprising a body part (herein: body) of the electrical connector or appliance which includes a cord aperture through which a cord enters the connector or appliance, a locking ring engagable on said body so that a passage through the locking ring aligns with the cord aperture, the locking ring comprising two connected parts rotatable relative to one another and about the passage through the locking ring, and locking means which in one relative rotational position of the locking ring parts allows rotational movement of the locking ring on the body and in another relative rotational position of the locking ring parts engages the body to inhibit rotation of the locking ring on the body.

Description

LOCK RING SYSTEM FOR AN ELECTRICAL CONNECTOR OR APPLIANCE

FIELD OF INVENTION

The invention relates to a lock system, for example for a cord clamp locking ring for an electrical connector such as a plug or socket connector, or an electrical appliance.

BACKGROUND OF INVENTION

Electrical connectors such as plug or socket connectors which are sold for installation after sale, to an electrical cord, commonl) comprise a locking ring which is tightened onto the body of the plug or socket connector around a cord apertuie into the connector , usually to form a strong physical connection between the bod) of the connector and the cord, additional to the electrical connections that are made between the wires of the cord and the pins of the plug or socket . The connector may also comprise a separate cord clamp for clamping the connector to the exterior of die cord.

SUMMARY OF INVENTION

It is an object of the invention to provide an improved or at least alternative form of lock system for example for a cord clamp locking ring for an electrical connector or appliance. In broad terms die invention comprises an electrical connector or appliance comprising a body (as herein defined) of the electrical connector or appliance which includes a cord aperture through which a cord enters the connectoi or appliance, a locking ring engagable on said body so that a passage thiough the locking ring aligns with the cord aperture, the locking ring comprising two connected parts rotatable relative to one another and about the passage through the locking ring, and locking means which in one relative rotational position of the locking ring parts allows rotational movement of the locking ring on the body and in another relative rotational position of the locking πng parts engages the body to inhibit rotation of the locking ring on the body.

Preferably said one or more locking parts which in said another relative rotational position of the locking ring parts is caused to protrude from the interior of the locking ring to engage the body to inhibit rotation of the locking ring on the body comprises one or more movable locking tabs associated with one of the locking ring parts, and wherein the other locking ring part comprises one or more cams which on movement of the two locking ring parts from said one relative rotational position to said another relative rotational position engage said one or more locking tabs to move said locking tabs to protrude from the interior of the locking ring. The movable locking tabs may be flexible locking tabs, which may be carried by, including integrally formed as pait of, an arcuate element around said passage through the locking ring tabs.

In a preferred form the locking ring also comprises second locking means which locks the two locking ring parts lelative to one another after movement of the locking ring parts from said one relative rotational position to said another relative rotational position, against return of the locking ring parts to said one relative position. A detent may be provided which is caused after movement of the locking ring parts from said one relative rotational position to said another relative rotational position to engage an outer part of the other locking ring part to lock against return of the locking ring parts to said one relative rotational position. Release means may enable manual release of the detent to enable movement of the locking ring parts back to said one relative rotational position.

In this specification the terms "cord" and "flex" are used interchangeably and as indicating one or more wires usually but not necessarily with a surrounding sheath often of a plastics material In this specification the term "body part" indicates that part of the body of the connector or appliance onto which the locking ring engages. The body part may be the whole of the body, of the plug or connector which will typically be a plastic moulded body, or a part of the bod) of the plug connector or appliance, such as a smaller part fixed to a larger body of an appliance, which a smaller part defines an aperture through which a cord passes into the appliance and has a threaded exterior onto which the locking ring engages.

The term 'comprising' as used in this specification and claims means 'consisting at least in part of, that is to sa₎ when interrupting independent claims including that term, the features prefaced by that term in each claim will need to be present but other features can also be present.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described with reference to the accompanying drawings which show preferred embodiments of an electrical connector and appliance of the invention, by way of example and without intending to be limiting. In the drawings:

Figure 1 is a perspective view of the exterior of a plug connector which comprises a preferred embodiment locking ring of the invention;

Figure 2 is a longitudinal cross-section of the plug of Figure 1;

Figure 3 is an enlarged longitudinal cross-section of the plug of Figures 1 and 2, of the locking ring and plug at one end of the plug also showing the end of a length of an electrical flex passing through the locking ring and a cord clamp, after the locking ring has been initially engaged onto the body of the connector but before the locking ring has been rotated fully home on the connector;

Figure 4 is a view similar to that of Figure 6 but after the locking ring has been rotated fully home on the connector;

Figure 5 is an exploded view of the locking ring of the plug of Figures 1 to 4;

Figure 6 is a perspective view of the locking ring and the end of die plug body on which the locking ring engages, with die locking ring parts in a relative rotational position that locking tabs of die locking ring do not protrude into the passage through the locking ring to lock the locking ring to the plug body;

Figure 7 is a view of the locking ring and end of the plug body similar to Figure 6 but showing the locking tabs protruding into the passage through the plug body to lock the plug body to die plug end;

Figure 8 is a view into the interior of the locking ring from one end in the direction of arrow C in Figure 6;

Figure 9 is a view similar to that of Figure 8, in the direction of arrow D in Figure 7;

Figure 10 shows an electrical appliance comprising the preferred forms of cord clamp at i.e. the end of the appliance.

DETAILED DESCRIPTION OF PREFERRED FORMS

Figures 1 and 2 show a preferred electrical plug. The plug comprises a body generally indicated at 1 and electrical (metallic) pins 2. The plug shown is a three phase plug of an industrial grading and optionally comprises a threaded locking ring 3 captive on the body 1 of the plug, which is screwed onto a complementary threaded body of a connector or appliance to which the plug is coupled in use.

In the particular form shown, within the body of the plug is retained a module 4 which comprises the pins 2. The individual wires (not shown) of a length of electrical cord or flex to which the connector is coupled are terminated at the other side of the module 4 within the body 1. A cord clamp is provided at the other end of the plug (herein sometimes referred to as the back end), generally indicated at 6. The cord clamp physically clamps the plug to the cord where the cord enters the body of the plug. When the plug is coupled to a cord or flex the cord C passes through an aperture 8 in an entry end of a locking ring 7, through an annular clamp component 6, and through an aperture 9 in the end of the connector body 1 as shown, into the interior of the plug body. - A -

Th e locking ring 7 in the prefeired form screw threads onto the body 1 of the plug At the back end of the plug the body 1 is externally threaded as indicated at 13, and a passage through the locking ring comprises an internally threaded portion 14 for threading the locking ring onto the plug body 1 Figure 3 shows the locking ring 7 after initial threading onto the bod_} Figure 4 shows the locking ring 7 after it has been screwed fully home onto the plug body. When the locking ring 7 is screwed fully home, the interior of the locking ring compresses the cord clamp component 6 tightly around the cord, to clamp and form a physical connection between the plug and the cord at the back end of the plug.

In the particular form shown a thrust washer 18 is provided within the locking ring adjacent the entry 8 to the locking ring and between the nut 7 and clamp component 6. The thrust washer 18 does not rotate as the locking ring is tightened on the clamp component 6, to assist in preventing rotational distortion of the clamp component 6, but a thrust washer 18 oi equivalent may not be essential Preferably the thrust washer 18 is retained within the interior of the locking ring so that it is not lost when die locking ring is removed. The thrust washer in the preferred form has a frusto-conical shape as shown

In the preferred form there is also provided a seal element 21 at the proximal end of the clamp component 6 for also sealing the clamp component to the body of the coupling as shown This seals against die potential ingress of moisture and dirt through the aperture 8 into the interior of the locking ring 7, and then around the lower annular face of the clamp component 6 The seal 21 ma) also be formed of the same material as, and as part of, die clamp component 6. In accordance with the invention means is provided for locking the locking ring 7 full) home on the plug body, to for example prevent the locking ring from loosening unintentional!) The locking ring 7 comprises two parts 10 and 11 which are connected but rotatable relative to one another about the passage through the nut. In the preferred form shown one of the parts 10 is relatively larger than the other part 11, so diat die part 11 forms a ring rotatable about the laigei part 10. Also die two locking ring parts 10 and 11 have a similar diameter, but alternatively the locking ring part 11 could have larger or smaller diameter than the part 10 Figure 5 shows the locking ring 7 in exploded form, and the assembled locking ring is shown in Figure 6 and 7 in it's relative rotational positions. To rotatably connect the locking ring parts 10 and 11, in the preferred form connection tabs 12 on the part 10 snap-fit into groves inside the part 11, when the two locking ring parts 10 and 11 which may be manufactured from a plastics material b} injection moulding for example, are assembled together. The connection of the parts 10 and 11 to form the locking ling 7 allows the two parts 10 and 11 to be rotatably moved relative to one anothei through at least a limited angle such as approximately 10 to 30 degrees of rotational movement for example. In the preferred form an arcuate element 15, which in the pieferred form comprises a metal strip, carries movable locking tabs 16 one at each end as shown, and in the assembled locking ring extends around a waisted portion 17 of the nut part 10 above the annular ride 20. The arcuate element 15 includes cut outs 19 to accommodate the connection tabs 12 on the nut part 10. The element 15 is associated with to move with the locking ring part 10. Locking tabs 16 are formed as cut outs from the arcuate metal strip 15, which may be formed of spring steel for example, so that the locking tabs 16 move by flexing relative to the main part of the arcuate element strip 15. Alternatively the locking tabs 16 may be otherwise hingably connected to the metal strip 15, or may alternatively for example be small plastic tabs which are formed as part of the waisted portion 17 of the locking ring part 10 rather than on a separate element strip 15. Cam parts 22 are provided on the interior of the other locking ring part 11, and are positioned so that in one relative rotational position of the locking ring parts 10 and 11 the cams 22 will contact the flexible locking tabs 16 and cause them to move or protrude into the passage through the locking ring. This is shown in Figures 4 and 7 The arcuate metal strip 15 carrying the locking tabs 16 is associated with and moves with the locking ring part 10, so that parts 10 and 11 can be rotated relative to one another to move the cams 22 relative to the flexible locking tabs 16. When the locking ring parts are in the relative position shown in Figures 3 and 6 the cams 22 on the locking ring part 11 do not align with the flexible locking tabs 16 which therefore are not caused to protrude into the passage through the locking ring, to engage the plug body. When the locking ring parts are moved to their relative position shown in Figures 4 and 7, the cam parts 22 on their locking ring part 11 move against the flexible locking tabs 16, causing them to engage with the plug body to lock the locking ring against further rotation on the plug body. Referring to Figure 6 to move the locking ring parts from the relative position shown in this Figure to that shown in Figure 7 it is necessary to rotate the locking ring parts 10 and 11 relative to one another in the direction(s) of arrow A in Figure 6. Referring to Figure 7 to move the locking ring from the relative position shown in Figure 7 to that of Figure 6 it is necessary to move the locking ring part(s) in the direction of arrow(s) B in Figure 7. Figuies 4 and 7 show the locking ring with it's two parts 10 and 11 in another relative rotational position, in which the cams 22 contact the flexible locking tabs 16 causing them to protrude into the passage through the locking ring. A series of ridges 23 are provided around the end of the plug body below the threaded portion 13 on the plug body, which are engaged by the protruding locking tabs 16 As stated, the arrangement is such that one relative rotational position of the locking ring 7 allows rotational movement of the locking ring on the plug body, enabling the locking ring to be threaded onto the plug body, and screwed home fully which in the pieferred form also compresses the cord clamp component 6 as ieferred to previously, while the other relative rotational position of the locking ring causes the locking tabs 16 to engage the ribs 23 on the plug body.

In the preferred form the locking tabs 16 are flexibly biased radially outwardly of the passage through the nut, so that when they are not contacted by the cams 22 the locking tabs 16 will return to a non-locking position. ^L

In the preferred form shown the ribs 23 are provided on the connector body below the threaded portion 13 thereof but alternatively the relative positions of the ribs 23 and threaded portion 13 on the body 1 may be reversed.

As referred to previously the locking tabs 16 may be flexible or one or more tabs may be provided which will move otherwise by pivoting or hinging for example, relative to one of the nut parts In the preferred form two locking tabs 16 are carried one each at or near the opposite ends of an arcuate spring steel element 15 but other arrangements are possible as referred to previously.

The preferred form electrical connector also comprises second locking means for locking the two locking ring parts in one relative position, which is releasable to enable the locking ring to be returned to it's original relative position to enable in turn the locking ring 7 to be unscrewed from the body of the plug. In particular the arcuate element 15 associated with the locking ring part 10 is bent intermediate of its length to define an outwardly facing detent 25, which interengages with a part (in particular shoulder 26b referred to subsequently) on the interior of the other locking ring part 11. The arrangement is such that when the locking ring part 11 is moved relative to the other part 10, from the one position in which the cams 22 do not engage the locking tabs 16, to the other relative position in which the cams 22 engage the flexible locking tabs 16, the detent 25 drops outwardly from recess 26a into recess 26b on the interior of the part 11 This prevents the locking ring part 11 from being returned to the first relative position until the detent 25 is first manually released from the recess 26b. In the preferred form shown an aperture 27 radially through the locking ring part 11 aligns with the detent 25 when the locking ring is in this second relative position, which enables a tool such as the end of a small screw driver for example, to be inserted through the aperture 27 to depress the detent 25 while parts 10 and 11 are then rotated back to their original position to withdraw the locking tabs 16, enabling the nut to be unscrewed from the plug body. This movement also returns the detent 25 to recess 26a, in the part 11.

Alternatively at the position of the aperture 27 a small button component may be provided in the locking ring part 11 , which may be depressed manually to release the detent 25 while the locking ring 11 is rotated, or a larger aperture 27 may be provided through which the detent 25 ma_} be direcdy pushed by a finger. In use the locking ring 7 may be screwed onto the body of the connector and then the locking ring part 11 rotated to through a small angle cause the detent 25 to drop into the recess 26 to lock the locking ring onto the plug body. Alternatively the orientation of the flexible locking tabs 16 is such that the locking ring part 11 may be rotated to cause the detent 25 to engage the recess 26 before the locking ring is engaged and rotated fully home on the plug body, with the locking tabs 16 riding over the ribs 23 on the plug body as the nut is screwed onto the plug body, with the locking tabs 16 engaging with the ribs 23 to prevent rotation of the locking ring in the opposite direction to unscrew the locking ring 7 from the body (until the detent 25 has been released as described above). The preferred form lock nut system described above is described in relation to a plug but alternatively may be provided at the back end of a socket connector and alternatively again may be used where a cord enters an electrical appliance. Figure 10 shows socket connector forming part of an appliance comprising a locking ring system of the invention. In Figure 10 similar reference numerals indicate similar components. The description of the preferred form above in relation to a plug connector is given by way of example only

In the preferred form shown the locking ring 7 threadedly engages onto the body 1 of the plug and in particular onto the back end of the plug. In an alternative form however the locking ring may engage onto the back end of the plug (or alternatively a connector or appliance) via a twist lock-type connection. In the preferred form the plug connector comprises the cord clamp component 6 but in other embodiments the cord clamp (if provided) may be in other forms. The cord clamp may be fingers integral with the end of the body which are compressed to engage the cord when the lock ring is tightened, rather than a separate component for example

The foregoing describes the invention including preferred forms thereof. Alterations and modifications as will be obvious to those skilled in the art are intended to be incorporated in the scope hereof as described in the accompanying claims.

Claims

CLAIMS:

1. An electrical connector or appliance comprising a body pait (herein- body) of the electrical connector or appliance which includes a cord aperture through which a cord enters the connector or appliance, a locking ring engagable on said body so that a passage through the locking ring aligns with the cord aperture, the locking ring comprising two connected parts rotatable relative to one another and about the passage through the locking ring, and locking means which in one relative rotational position of the locking πng parts allows rotational movement of the locking πng on the body and in another relative rotational position of the locking ring parts engages the body to inhibit rotation of the locking ring on the body.

2. An electrical connector or appliance according to claim 1 wherein said locking means includes one or more locking parts which in said another relative rotational position of the locking ring is caused to protrude from the interior of the locking ring to engage the bod) to inhibit rotation of the locking ring on the body.

3. An electrical connector or appliance according to either one of claims 1 and 2 wherein the locking ring comprises second locking means which locks the two locking πng parts relative to one another after movement of the locking ring parts from said one relative iotational position to said another relative rotational position, against return of die locking πng parts to said one relative position

4. An electπcal connector or appliance according to claim 3 comprising an aperture radialh through one of the locking nng parts enabling insertion of a tool through said apeituie to release said second locking means to enable return of the two locking ring parts relative to one another from said another relative rotational position to said one relative position.

5. An electπcal connector or appliance according to any one of claims 2 or 3 and 4 when dependent on claim 2 wherein said one or more locking parts which in said another relative rotational position of the locking ring parts is caused to protrude from the interior of the locking ring to engage the body to inhibit rotation of the locking ring on the body comprises one or more movable locking tabs associated with one of the locking ring parts, and wherein the other locking ring part comprises one or more cams which on movement of the two locking ring parts from said one relative rotational position to said another relative rotational position engage said one or more locking tabs to move said locking tabs to protrude from the inteπor of the locking ring

6. An electncal connector or appliance according to claim 1 wherein said locking means includes an arcuate element around said passage through the locking ring and which is carried by one of the locking ring parts or is captive between the two locking πng parts and which carries said one or more movable locking tabs.

7. An electrical connector or appliance according to eithei one of claims 5 and 6 wherein said one or more movable locking tabs are flexible locking tabs.

8. An electrical connector or appliance according to either one of claims 6 and 7 comprising at least two of said movable locking tabs, one each at or towards opposite ends of said arcuate element.

9. An electrical connector or appliance according to either one of claims 7 or claim 8 when dependent on claim 7 wherein said arcuate element comprises a metal strip which integrally comprises said flexible locking tabs

10. An electrical connector or appliance according to any one of claims 6 to 9 when dependent directly or indirectly on claim 3 wherein said arcuate element is earned by an inner part of one of the locking ring parts and comprises intermediate of its length a detent which is caused after movement of the locking ring parts from said one relative rotational position to said another relative rotational position to engage an outer pait of the other locking ring part to lock against return of the locking ring parts to said one relative rotational position

11. An electrical connector or appliance according to claim 10 wherein release means associated with said outer part of one of the locking nng parts enables manual release of said detent to enable movement of the locking ring paits back to said one relative rotational position.

12. An electrical connector or appliance accoiding to claim 11 wherein said release means includes an aperture radiall₎ through said outer part of one of the locking nng parts enabling manual release of said detent through said apertuie

13. An electrical connector or appliance accoiding to any one of claims 1 to 12 wherein one of the locking ring parts is relatively larger and the other is relatively smaller and compnses a locking nng rotatable about said larger locking ring part.

14. An electrical connector or appliance according to any one of claims 1 to 13 also comprising an annular clamp component within said passage through the locking ring and compnsing a passage axially through the clamp component, the intenor of the locking ring being arranged to engage cord engaging elements of the clamp component when the locking ring is engaged home on the body to cause the cord engaging elements to move towards one another

15. An electrical connector or appliance according to claim 14 comprising an annular seal element for sealing about a cord at a distal end of the clamp component.

16. An electrical connector or appliance according either one of claims 14 and 15 including a seal element at a proximal end of the clamp component for sealing the clamp component to the body about the cord aperture.

17. An electrical connector or appliance according to anyone of claims 1 to 16 wherein a part of the body of the electrical connector or appliance is externally threaded and the locking ring is internally threaded for threading onto the body.