GB2223701A

GB2223701A - Nut

Info

Publication number: GB2223701A
Application number: GB8920981A
Authority: GB
Inventors: David Woods; Paul Jackson
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-09-15
Filing date: 1989-09-15
Publication date: 1990-04-18
Anticipated expiration: 2009-09-15
Also published as: GB2223701B; GB8821613D0; GB8920981D0

Abstract

A conduit nut 28 has projections 29 on at least one side thereof arranged and disposed to encounter material of an electrical enclosure to restrain the nut 28 against rotation during securement of a fitting thereto. The nut is fabricated from an annular blank having a central aperture and a multi-pointed outer periphery. The pointed positions of the blank are deformed out of the plane of the blank to form the projections 29. <IMAGE>

Description

NUT This invention relates to a gland or conduit nut, that is to say a nut which is used within an electrical enclosure to secure a conduit fitting passing through wall of the enclosure, and to a filling incorporating such a nut.

Fig. 1 illustrates one known type of conduit fitting 10 in combination with an electrical enclosure 11 enclosing apparatus 12 to which cables 13 within conduit 14 are connected. The conduit is usually secured to a fitting 10 by means of an olive ring 15.

When the fitting 10 is to be secured to the wall 16 it is screwed onto a threaded spigot of the fitting 10. It will be appreciated that it is quite difficult, in the confined space of the enclosure 11, to fit a reasonable spanner onto the nut 17 to tighten it securely against the wall 16. Further, when the olive ring 15 is tightened against the fitting 10 it is not at all unusual for the whole fitting 10 and the nut 17 to turn together, thus preventing the olive ring 15 from becoming properly tight. It is possible to use a grip washer between the nut 17 and the wall 16, but the use of a separate component increases costs. Further, to manipulate a separate locking ring between the nut 17 and the wall 16 is quite difficult in the confined space of the enclosure 11.There is a further requirement of such fittings that they provide an earth connection whereby the fitting 10 and the wall 16 (if it is of metal) can be connected to an earth within the circuitry. It is known to use an annular tag washer between the nut 17 and the wall 16 but, this again, complicates matters and can interfere with the function of any grip washer.

Further gland nuts are known, for example from U.S. Specification No. 4022262 and British Specification 1206690 to provide gland nuts which have projections for engaging material of junction boxes in order to achieve a secure connection which firstly makes a good earth connection and secondly resists untwisting.

However, in each of these prior documents the nut in question is provided with outwardly extending castellations which are bent out of the plane of the body of the nut and which present an edge of some significant peripheral extent for engagement with the material of the box. Such nuts are satisfactory when, for example, light or flexible conduit is being secured, because the loads applied thereto are relatively small. For rigid metal conduit and heavier uses, such nuts are ineffective. The significant circumferential length of the "biting" portions is so great that the force applied to the nut is not sufficient to maintain their engagement with the material of the box when under strain.

It is an object of the present invention, therefore, to provide a method of manufacturing a gland nut results in a nut which has superior locking and earthing qualities to those described above and also to a nut manufactured by the method.

According to the invention there is provided a locking nut which is formed by a method involving the following steps: forming an annular blank having a central circular aperture and an outer periphery having a plurality of points; deforming portions of said annulus adjacent said points out of the plane of the blank to form; pointed projections extending out of the plane of the blank; and forming a thread on walling of said aperture within the thickness of the said annulus.

Preferably the entire thickness of the blank over said portions is deformed.

The annular blank can be polygonal in plan, for example rectangular, pentagonal or hexagonal, preferably hexagonal. Alternatively, the blank can be generally circular with spaced projections around its periphery.

Preferably, the bending is done by supporting the blank against an anvil whose size is less than that of the blank, those portions to be bent overhanging the anvil and being contacted by punchment so as to move them out of their plane of the blank.

Preferably said anvil has an edge which faces each portion to be bent. Preferably, each said face has an end which coincides with an edge portion of the blank to ensure that each portion of the blank which is bent is bent about a line which meets the periphery of the blank.

This ensures that the bending of each portion is independent of the bending of the each other portion.

Preferably in the case where the blank is polygonal the anvil is polygonal and has apices at or adjacent the mid point of each side of the blank.

Preferably the blank is of mild steel having a thickness of from 2mm to 4mm. The maximum radial width of the blank can be from 20% to 50% of the diameter of the central aperture. The minimum radial width of the blank can advantageously be from 16 to 30% of the diameter of the central aperture. The ratio of the minimum radial diameter to the maximum radial diameter can be from 1:1.5 to 1:4.

Preferably the deformation is done in such a way as to ensure that each corner of the blank, after forming has an edge line which extends parallel to the axis of the aperture.

The invention also provides a method of forming a connection between a gland body and a junction box comprising providing an aperture in the box, passing a threaded male portion of the gland through the aperture in the box and engaging it with a gland nut having a plurality of pointed projections extending towards the wall of the box, holding the nut stationary with its projections in engagement with the wall of the box whilst rotating the gland to cause the nut to be urged towards the box so as to cause its points to penetrate the material of the box to restrain it against rotation.

The non-rotation of the nut means that other items can be secured by means of the nut which is not really possible when the nut is rotated. An example of these is a washer bearing an earth tag.

Alternatively, the nut itself can be provided with an earth terminal, which terminal could be pre-positioned within the box.

The invention also provides a gland nut having a plurality of projections extending from one face thereof for engagement with material of a wall of a conduit box the nut being provided with an earth terminal.

The invention additionally provides a gland or conduit nut having on at least one face thereof one or more projections adapted to penetrate a surface of an enclosure wall and restrain the nut against rotation relative thereto, said projections having been formed by deforming peripheral parts of a nut-forming blank to extend out of the plane thereof on one side of the blank.

Preferably there are a plurality of such projections. For cheapness the projections can be on one side only of the nut.

The deformation can be effected by pressing over peripheral portions of the nut, for example at the apices of the nut.

Alternatively, the projections can be formed by pressing portions of the nut web out of their normal plane.

For stability, it is desirable that there are at least three so-formed projections on one side of the nut. Preferably, there at least four such projections. When less than three projections are provided in a gland nut whose central aperture is large compared to the radial width of the nut, small numbers, i.e. one, two or, some times, three projections can lead to instability and possible malfunction. Further, few projections can give inadequate grip, or can result in unacceptable deformation of the material of the box and/or the nut.

To facilitate the formation of the nut the material of the blank can be rendered thinner adjacent the projection positions.

To provide for an earth connection an earth terminal can be secured to the nut. Because the nut is adapted to be restrained against rotation, the position of the earth terminal within the enclosure can be determined by the user and is not dependent upon turning of the nut.

The invention also provides a gland assembly including a gland body having: a through-passage; a small threaded spigot for entering a conduit box; and a part for receiving a length of conduit, a conduit-securing sleeve attachable to said part, and a gland nut engaged with said spigot, said nut having projections extending towards the body.

In using this gland assembly the nut is removed from the spigot and the spigot passed through an aperture in a conduit box or like fitting. The nut is then lightly screwed towards its securement position.

If the nut carries an earth terminal, the desired position of the earth terminal within the box or other fitting can now be determined and the nut held in position (for example manually) whilst the body of the gland assembly is rotated so as to draw the body and the nut together, the nut projections moving in an axially parallel direction into the material of the box or fitting to make a secure contact therewith which resists unfastening due to vibration and which, in the case of a metal box forms a secure earth connection therewith. The provision of the nut with the projections enables the user to dispense with any spanner or like tool within the box. This is most advantageous because the interior of such boxes is often cramped and the use of tools therein is not always easy.Further, the ability to have an earth terminal either on the nut or on a separate washer fixed in position and which does not rotate during tightening of the fixture is very advantageous, it enable an earth terminal to be secured and located at a desirable position in relation to other fittings and other connections.

The invention will be described further, by way of example, with reference to the accompanying drawings wherein Fig. 1 is a part sectional view illustrating a prior known electrical enclosure and an associated prior known fitting and nut; Fig. 2 is an enlarged fragmentary view illustrating comparable parts of an enclosure provided with the nut of the invention; Fig. 3 is an enlarged cross-sectional view of a preferred nut of the invention illustrating a first manner in which projections can be formed.

Fig. 4 is a front elevation of the nut of Fig.3; Fig. 5 is a view comparable to Fig. 3 but illustrating a different mode of formation of the projections; Fig. 6 is a perspective view illustrating a further possible way in which the projections on the nut can be formed; Fig. 7 is a cross-sectional view illustrating a running coupling using the nut of the invention.

Fig. 8 is a plan view of a blank for use in making a nut of the invention; Fig. 9 is a cross-sectional view on line 1X to 1X of Fig. 8; Fig. 10 is a cross-sectional view on line X to X of Fig. 8; Fig. 11 is a view similar to that of Fig. 8 but showing the blank on a large scale; Fig. 12 is a cross-sectional view on the line Xll to Xll of Fig. 11 illustrating deformation of material of the blank; Fig. 13 is a sketch also on the line Xll to Xll of Fig. 11 illustrating the blank after deformation; and Fig. 14 is a side view of the preferred nut of the invention and Fig. 15 is a view similar to that of Fig. 12 but illustrating a variation.

Referring to Fig. 2 it will be seen that there is an electrical enclosure 18 which has a side wall 19 with an aperture 20. A conduit fitting 21 has a body 22 and a spigot 23 which is externally threaded and which projects into the enclosure 18. The body 22 has a knurled or non-circular portion 24 and an external grip spigot 25. A solid or flexible conduit 26 can be secured to the spigot 25 in conventional manner by means of an olive ring 27. Spigot 23 is threadedly engaged with a nut 28 of the invention which is of conventional hexagonal form. The nut 28 has a plurality of sharp projections 29 formed one at each of its apices. Each projection 29 is formed by deforming material of the nut outwardly from its plane after manufacture.

When assembling the fitting 21 to the wall 19 the spigot 23 is passed into the enclosure and the nut 28 turned by hand so that its projections 29 engage the wall 19. The position of an earth terminal 30 can be pre-positioned around the periphery of the spigot 23 to be in an outer accessible place. Once the nut has been positioned the body 22 can be turned by means of the knurled ring 24. There is no need for the nut 28 to be held during final tightening of the body 22. The union is particularly tight and hard and afterwards even when the olive ring 27 is tightened there is no tendency for the body 22 to rotate.

Referring to Figs. 3 and 4 it will be seen that in a nut 28 projections 29 can be formed by holding the nut in a press with apices of the nut slightly overhanging an edge and causing a downwardly deforming force in the direction of arrow 31. As such nuts are normally made from mild steel such a deformation is quite simple and within the capacity of a relatively small press.

An alternative form of effecting a comparable deformation is shown in Fig. 5 wherein the angle of bending is less severe and the point 32 is formed by the angle between the end face 33 and the major face 34 of the nut.

Fig. 6 illustrates a further possibility wherein a nut 36 has, in each of its sides 37 a tooth 38 which is formed by pressing outwardly from the plane of the nut a small portion of that side part. The direction of the teeth 38 should be rendered compatible with the direction of rotation of the nut. In Fig. 6 the normal direction of the nut tending to unfasten would be in the direction of arrow 39. It will be appreciated that the nut of Fig. is a left-handed nut, however, the application of the same principle to a right handed nut will easily be appreciated.

From the aforesaid description it will be appreciated that the nut of the invention allows for particularly simple union to be made between a conduit fitting and an electrical enclosure. The projections on the nut allow it to remain non-rotatably secured to the wall during all operations on the fitting.

Further, the projections provide a good earth contact with metal wall enclosures and can be used to mount a small simple earth terminal which is positioned in relation to the enclosure at the will of the operator and is not dependent upon random turning effects of the nut.

It will be appreciated that the shape, size and dimensions of the various points can be chosen to suit any convenient manufacturing process. In particular, it is expected that by knurling a nut on its operative face appropriate projections could be created. Again, comparable projections could be created by coarse grinding or sanding perhaps transversely across the whole nut. The nut of the invention eliminates both the need for a separate locking washer with its attendant possibility of loss and very fiddling manipulation inside the box and also the need for a separate annular earth tag washer in circumstances where such is needed. The use of a spanner within the confines of an electrical enclosure is eliminated and thw whole process is greatly accelerated.

The nut of the invention can also be used in combination with a running coupling which is used in situations where there is insufficient room to manipulate independent lengths of conduit in order to make a neat fitting. This is illustrated very briefly in Fig. 7. In the running coupling two pieces of conduit 40,41 have to be joined end-to-end and there is not sufficient space to move either longitudinally to accommodate a conventional coupling. In these instances each end of the two pieces of conduit 40,41 is threaded and a threaded sleeve 42 is slid over one of them. After alignment of the two pieces of conduit the threaded sleeve 42 is turned to the operative position illustrated at 43 in dotted lines.

A nut 44 of the invention can then be tightened, in the position shown at 44a in Fig.7 against the end of the sleeve 43. The nut 44 with its projections 45 forms a firm lock with the sleeve 43 and secures it against loosening due to vibration or the like.

In manufacturing a preferred nut 50 of the invention a blank 51 is formed (Figures 8, 9, 10 and 11) which has a thickness of from 2 to 4mm (preferably 3mm) and whose dimensions D (Figures 9 and 10) is 19mm. Dimension W is 6mm and w is 4mm. The maximum radial width of the blank (effectively defining the distances of the eventual points from the central aperture can vary from 20 to 50% of the diameter of the central aperture. If the radial width falls below 20% the overall strength of the nut tends to be reduced below an acceptable level. Above 50%, and the distance of the points from the edge of the central aperture tends to allow the material of the nut to bend, when made from material of a reasonable thickness. The minimum radial width of the blank can be from 15 to 30% of the diameter of the central aperture.Below 15%, the nut again tends to become rather flimsy and above 30% adding further material does not add significantly to the strength necessary.

The above ratios are, of course, subject to the inter-relationship between the minimum and maximum radial diameter. It has been found that the ratio of the minimum radial diameter to the maximum radial diameter can be in the range from 1:1.5 to 1:4.0.

Below the first limit, the difference between the two diameters is so low that the pointed portions of the blank are not sufficiently prominant to allow relatively simply bending of the material of the blank. Beyond the second range, the points tend to be so far spaced from the central aperture that the nut becomes rather too large, and bending of the material of the nut can occur in use. Further, such a large ratio does lead to a nut which is, for example, approaching squareness, which nut is quite difficult to manipulate in a relatively small space in that it requires a lot of radial room in which to rotate. The ranges chosen are, of course, practical ranges, chosen from a spectrum of values wherein the properties range from good towards indifferent.

In deforming the blank 51 to make the nut 50, a central portion 52 is supported on an anvil 53. It will be noted, of course, that the blank 51 has a hexagonal outer profile. This is much the preferred shape as it allows a conventional spanner to be used to turn the nut. Although a square or other shaped nut could be manufactured, a square nut tends to have relatively weak areas between its points (see the reference to ratios above) and also requires a significant space in which to rotate. This is detrimental when use inside a conduit box is envisaged. We have found it very convenient to use an anvil which matches the polygonality of the blank, that is to say in the present example the anvil is itself hexagonal, having an apex coincident with or very close to the mid point of each side of the hexagon of the blank. The outline of the anvil is shown at Figure 3 and Figure 11.As is shown in Figure 12, the central portion 52 is clamped on the anvil 53 by means of a holder 54. A hexagonal hollow punch member 55 (only one portion of which is shown) is then urged towards the anvil 53 to contact the outer portion 56 of the blank 51 and deform them downwardly to the position illustrated in the sketch of Figure 13. Clamping of the central portions ensures that the material surrounding the central aperture 57 ensures that the shape of the aperture 57 is not significantly changed and can very easily be threaded in a subsequent conventional threading operation.

With reference to Figures 13, 14 and 15 it will be seen that the deformation of the outer portions 15 results in the creation of six pointed projections 58, one at each apex of the nut. As can be seen from Figs. 14 and 15, each point is defined by three lines, a line 59 which is a junction between two of the faces of the blank 51 and which line 59 extends generally parallel to the axes of the aperture 57 and two lines 60. It will be seen that each line 60 is the edge between the face of one side of the hexagon of the blank and that face junction with the underside of the blank (as shown in the drawings). The sharpness of the point can be controlled quite accurately to suit the materials being used by control of the angle (Fig. 14) by which the portions 56 are bent downardly from the plane of the blank 51.Desirably, the angle a has a minimum value of 10 (below which the point is rather ineffective) and a maximum value of about 350. A preferred angle for a mild steel nut has been found to be about 25 .

The particular points formed are particularly suitable for use in the manufacture of mild steel nuts for use with conduit boxes of mild steel or other metal such as brass or alloy. It has been found that the point 58 are adequate to engage the material of the box not only to restrain the gland or comparable fitting against rotation but also, in the case of metal boxes, to form a good earth contact with the box. Further, as the fitting can be secured to the box without rotation of the nut, it is possible for the nut to be provided with an earth terminal such as a terminal 30 for connection to other structure within the box. or like fitment. Such arrangement is particularly suitable in a box made of non conducting material when there is a need for earth continuity between the gland or comparable fitting and the other components in the box.Because the nut does not rotate during fitting of the gland or other fitments, the position of the terminal can be predecided within the box and placed in a position where it can be conveniently accessed and tightened. This advantage is particularly great in relation to the three part gland fitting which is illustrated in Fig. 2. When the gland body 24 is provided with means whereby which it can be turned (for example a knurled annulus or a body containing one or more flats or the like, the use of a non-rotatable nut within the box has many advantages as outlined above. When the body 24 has been secured, the gland nut 27 can be attached, as by screwing to secure the conduit 26. It will be appreciated, of course, shapes of anvil other than that described can be used. Fig. 15 illustrates how an anvil of the same shape as the anvil 53 can be used, but in comination with a pressing tool in the form of a circular annulus 61 which is effective to contact only outer portions of the blank and deflect them downwardly. In a similar manner a central circular anvil can be used and a press tool provided which contacts only outer portions of the blank 51.

However, it should be noted that it is extremely desirable that the bend lines formed in the material of the blank extend for a significant distance. Such lines can be seen at 62 in Figures 13 and 15. It will be seen that the provision of the relatively elongate bend lines 62 form the material of the blank into channel section portions. This shaping of the blank to a plurality of channel sections (whether they are continuously connected or spaced apart by unbent portions) gives the formed blank much greater rigidity than a plain nut. This enables relatively lower quantities of material to be used for the nut than will be necessary without such bending to give the channel sections strength.

Preferably, each face of the anvil has an end which coincides with an edge portion of the blank.

this is mentioned above, this ensures that each portion of the blank when it is being bent, is bent about a line which meets the periphery of the blank.

this has the effect that the bending of each portion is independent of the bending of each other portion and therefore there is no part, at the junction of two bends, in which the material is being doubly deformed with the possibility of excessive strain in the material resulting in excessive resistance to bending.

As described, it will be seen that there are six projection on the periphery of the nut. For stability it is desirable that there are at least three projections and they only need to be on one side of the nut. A double sided nut having three projections on each side could be used, but it is not thought to be a necessary or practical embodiment. Preferably there are at least four projections on the nut and desirably the projections are equally spaced around the nut. Thus, it is felt that a four projection square nut will be the minimum size of nut which could operate with reasonable efficiency. When less than three projections are provided in a gland nut whose central aperture is large compared to the radial width of the nut, small numbers i.e. one, two or (sometimes) three projections can lead to instability and possible malfunction.Further, few projections can give inadequate grip or can result in unacceptable deformation of the material of the box and/or the nut.

The nut of the invention is quite simple and easy to manufacture. It is envisaged that the nut will normally be embodied in a hexagonal form or, in possible applications in a square form wherein there are four projections. The great advantage of the hexagonal form is, of course, that it takes up relatively little radial room beyond the periphery of the aperture. In order that a square nut can be sufficiently strong at the junctions between its points, the side thereof has to be quite long leading to a relatively large diagonal diameter which increases the space needed within a conduit box.

Further, the advantage of both the square and hexagonal nut is that it is compatible with common spanners and does not require special tools as do castellated nuts. When the nut has to be removed (for example if, upon removal, of the fitting corrosion has tightened it upon the spigot) it can be turned using conventional spanners. As will be appreciated from the various dimensions given in relation to Figures 8 to 14, the body of the nut must be essentially non-resilient in order that the force applied to the points 58 by the relative screwing between the nut and the spigot in use urges the points to penetrate the material of the box without any significant springing.

Above it has been mentioned that the bend line 62 creates a channel section structure which is best seen in Figure 13. A further advantage of the rather long bend lines within the material of the annulus, are virtually continuous throughout the circumferential direction of the annulus is that such lines create a degree of work hardening in use which again reduces springiness of the material and makes the material rather stronger and less likely to deform in use.

Many other variations can be made to the invention within the scope of the following claims.

Claims

1. A method of making a locking nut including: forming an annular blank having a central circular aperture and outer periphery having a plurality of points; deforming portions of said annulus adjacent said points out of the plane of the blank to form; pointed projections extending out of the plane of the blank; and forming a thread on walling of said aperture within the thickness of the said annulus.

2. A method of making a locking nut as claimed in claim 1 wherein the entire thickness of the blank over said portions is deformed.

3. A method of making a locking nut as claimed in claim 1 or 2 wherein the annular blank is polygonal.

4. A method of making a locking nut as claimed in claim 3 wherein the blank is rectangular, pentagonal or hexagonal.

5. A method of making a locking nut as claimed in claim 3 wherein the blank is generally circular with spaced projections around its periphery.

6. A method of making a locking nut as claimed in any of claims 1 to 5, wherein the deformation is effected by supporting the blank against an anvil whose size is less than that of the blank, those portions to be bent overhanging the anvil and being contracted to move them out of the plane of the blank.

7. A method of making a locking nut as claimed in claim 6 wherein said anvil has an edge which faces each portion to be bent.

8. A method of making a locking nut as claimed in claim 7, wherein each said face has an end which coincides with an edge portion of the blank to ensure that each portion of the blank which is bent about a line which meets the periphery of the blank.

9. A method of making a locking nut as claimed in claim 7 or 8, wherein the blank is polygonal and the anvil is polygonal and has apices at or adjacent the mid point of each side of the blank.

10. A method of making a locking nut as claimed in any preceding claim wherein the blank is of mild steel having a thickness of from 2mm to 4mm.

11. A method of making a locking nut as claimed in any preceding claim wherein the maximum radial width of the blank is from 20% to 50% of the diameter of the central aperture.

12. A method of making a locking nut as claimed in any preceding claim wherein the minimum radial width of the blank is from 16 to 30% of the diameter of the central aperture.

13. A method of making a locking nut as claimed in any preceding claim wherein the ratio of the minimum radial diameter to the maximum radial diameter is from 1:1.5 to 1:4.

14. A method of making a locking nut as claimed in any preceding claim wherein the deformation is done in such a way as to ensure that each corner of the blank, after forming has an edge line which extends parallel to the axis of the aperture.

15. A conduit or gland nut made by the method of any of claims 1 to 14.

16. A method of forming a connection between a gland body and a junction box comprising providing an aperture in the box, passing a threaded male portion of the gland through the aperture in the box and engaging it with a gland nut having a plurality of pointed projections extending towards the wall of the box, holding the nut stationary with its projections in engagement with the wall of the box whilst rotating the gland to cause the nut to be urged towards the box so as to cause its points to penetrate the material of the box to restrain it against rotation.

17. A method of forming a connection as claimed in claim 16, wherein one or more other items are secured by means of the nut.

18. A method of forming a connection as claimed in claim 17, wherein the item is a washer bearing an earth tag.

19. A method of forming a connection as claimed in claim 16 or 17 wherein the nut is provided with an earth terminal.

20. A method as claimed in claim 1 wherein there are at least three so-formed projections on one side of the nut.

21. A method as claimed in claim 20, wherein there at least four such projections.

22. A method as claimed in any of claims 1 to 15 or claim 20 or 21, wherein to facilitate the formation of the nut, the material of the blank is rendered thinner adjacent the projection positions.

23. A method as claimed in any of claims 1 to 15 or claim 20, 21 or 22, wherein an earth terminal is provided on the nut.

24. A gland assembly including a gland body having: a through-passage; a male threaded spigot for entering a conduit box; and a part for receiving a length of conduit: a conduit-securing sleeve attachable to said part; and a gland nut engaged with said spigot, said nut having projections extending towards the body.

25. An gland assembly as claimed in claim 24, wherein the nut carries an earth terminal.

26. A method as claimed in any of claims 1 to 16, wherein the deformation of the nut is such as to render portions of the nut of channel section.

27. A gland nut having a plurality of projections extending from one face thereof for engagement with material of a wall of a conduit box the nut being provided with an earth terminal.

28. A gland or conduit nut substantially as hereinbefore described with reference to and as illustrated in Figs. 2 to 14 of the accompanying drawings.

29. A method of forming a union between a gland body and a junction box substantially as hereinbefore described with reference to the accompanying drawings.

30. A gland assembly substantially as hereinbefore described with reference to the accompanying drawings.