The present invention relates to gland assemblies. The invention has particular, but not exclusive, application to gland assemblies for sealing around electrical cables. However, the invention also has application to gland assemblies for sealing around fibre optic cables, pipes and other conduits.

Cable gland assemblies are commonly used for sealing around a cable passing through an opening in a wall through which the cable passes. For example, cable gland assemblies may be used to seal around a cable entering an enclosure such as a junction box containing electrical equipment to prevent fluids entering or exiting the enclosure. A typical sealing arrangement employs a seal member that surrounds a cable extending through the gland assembly and is urged inwardly to engage and seal around the cable when two parts of the gland assembly are screwed together. With this type of sealing arrangement, problems can arise due to incorrect tightening of the gland parts.

Thus, over-tightening of the gland parts can cause cold flow of the material forming the outer sheath of the cable under the seal member which can have an adverse effect on the efficiency of the seal obtained. Under-tightening of the gland parts may reduce the efficiency of the seal obtained. The gland parts may also be susceptible to becoming loose due, for example, to vibration reducing the efficiency of the seal obtained.

Controlling tightening of the gland parts can be a particular problem in cable gland assemblies designed for use with a range of cable sizes where the degree of tightening required for different cable sizes may vary with the result that achieving the required degree of tightening depends on the skill and care of the operative installing the gland assembly.

The present invention has been made from a consideration of the foregoing and seeks to provide a gland assembly which overcomes or at least mitigates the aforementioned problems.

It is a desired aim therefore of the present invention to provide a gland assembly in which movement of a gland part by applying a torque to the gland part to create a seal around an elongate member extending through the gland is controlled to prevent over-tightening the gland part regardless of the torque applied.

It is another desired aim of the present invention to provide a gland assembly in which loosening of threadably engaged gland parts is prevented.

According to one aspect of the invention, we provide a gland assembly for an elongate member extending, in use, through the gland assembly, the gland assembly including a gland member that is movable in response to an applied torque to cause a seal member to seal around the elongate member, wherein the gland member is provided with a torque transmitting device operable to inhibit over-tightening the gland member.

By inhibiting over-tightening of the gland member, the force exerted on the seal member by the gland member can be controlled, regardless of the torque applied to the torque transmitting device. In this way, where the elongate member is a cable, for example an electric cable or fibre optic cable, problems due to cold flow of the material of the outer sheath of the cable caused by the seal member when the gland member is over-tightened can be avoided or significantly reduced.

It may be that rotation of the gland member in a first direction tightens the gland member and applies a force to cause the seal member to seal around the elongate member. It may be that rotation of the gland member in a second direction loosens the gland member. Rotation of the gland member by an applied torque in the first direction may cause axial movement of the gland member to tighten the gland member and apply a force to the seal member so as to urge the seal member to seal around the elongate member.

The torque transmitting device may comprise a sleeve member. The sleeve member may fit over and/or around all or part of the gland member. The sleeve member may have a hollow body portion. The hollow body portion may receive all or part of the gland member.

The sleeve member may transmit torque to the gland member for tightening the gland member. Torque may be transmitted up to a pre-determined level above which torque is not transmitted to prevent over-tightening the gland member. It may be that the sleeve member is rotatable with the gland member to transmit torque applied to the sleeve member to the gland member for tightening the gland member and is rotatable relative to the gland member to isolate the gland member from torque applied to the sleeve member for preventing over-tightening of the gland member. The sleeve member may rotate with the gland member in a direction to tighten the gland member to a required degree and then rotate relative to the gland member so that over-tightening of the gland member can be avoided.

The sleeve member may have one or more formations arranged to engage the gland member so that the sleeve member can rotate with the gland member whereby torque applied to the sleeve member is transmitted to the gland member for tightening the gland member. The or each formation may be capable of deforming to disengage the gland member so that the sleeve member can rotate relative to the gland member whereby torque applied to the sleeve member is not transmitted to the gland member for preventing over-tightening of the gland member.

The or each formation may be arranged on an internal surface of the sleeve member. The or each formation may extend in an axial direction. The or each formation may extend substantially parallel to an axis of rotation of the gland member. The or each formation may be engageable with an abutment on the gland member for transmitting torque applied to the sleeve member to the gland member. The or each abutment may be arranged on an external surface of the gland member. The or each abutment may extend in an axial direction. The or each abutment may extend substantially parallel to an axis of rotation of the gland member. The or each formation may be configured to ride over the abutments to prevent over-tightening the gland member.

The sleeve member may transmit torque to the gland member for loosening the gland member.

The or each formation may be engageable with a further abutment on the gland member for transmitting torque applied to the sleeve member to the gland member in the second direction to release the gland member, i.e. to loosen the gland member. The or each formation may be configured to maintain engagement with the further abutments to release the gland member. The or each further abutment may be arranged on the external surface of the gland member. The or each further abutment may extend in an axial direction. The or each further abutment may extend substantially parallel to an axis of rotation of the gland member.

It may be that the gland member is engageable with a further gland member. The sleeve member may be operable to transmit torque for rotating the gland member relative to the further gland member for tightening the gland member on the further gland member. The sleeve member may be operable to inhibit rotation of the gland member relative to the further gland member for maintaining a tightened position of the gland member and inhibiting loosening of the gland member. The gland member may be engageable with the further gland member by means of mating screw threads.

The sleeve member may be movable in an axial direction relative to the gland member between a release position for rotation with the gland member relative to the further gland member when tightening the gland member and a locking position for engaging both gland members to inhibit relative rotation of the gland member and further gland member.

According to another aspect of the invention, we provide a method of assembling a gland assembly to control a force exerted on a seal member by a gland member that is movable in response to an applied torque to tighten the gland member and cause the seal member to seal around an elongate member extending through the gland assembly, the method including providing the gland member with a device for transmitting an applied torque to the gland member for tightening the gland member wherein the device is configured to inhibit over-tightening the gland member.

By employing a torque transmitting device to inhibit over-tightening of the gland member, the force exerted on the seal member by the gland member can be controlled regardless of the torque applied to the torque transmitting device so that cold flow of the material of the outer sheath of the cable can be avoided or significantly reduced.

The torque transmitting device may be configured to rotate with the gland member in a direction to tighten the gland member to a required degree and then to rotate relative to the gland member so that over-tightening of the gland member can be avoided.

The torque transmitting device may comprise a sleeve member. The sleeve member may fit over and/or around all or part of the gland member. The sleeve member may have a hollow body portion. The hollow body portion may receive all or part of the gland member. The sleeve member may be provided with one or more formations engageable with the gland member for transmitting torque applied to the sleeve member to the gland member for tightening the gland member. The formations may deform when the gland member has been tightened to the required degree to permit the sleeve member to rotate relative to the gland member. The or each formation may be arranged on an internal surface of the sleeve member. The or each formation may extend in an axial direction. The or each formation may extend substantially parallel to an axis of rotation of the gland member. The or each formation may be engageable with an abutment on the gland member for transmitting torque applied to the sleeve member to the gland member. The or each abutment may be arranged on an external surface of the gland member. The or each abutment may extend in an axial direction. The or each abutment may extend substantially parallel to an axis of rotation of the gland member. The or each formation may be configured to ride over the abutments to prevent over-tightening the gland member.

The sleeve member may transmit torque to the gland member for loosening the gland member. The or each formation may be engageable with a further abutment on the gland member for transmitting torque applied to the sleeve member to the gland member in the second direction to release the gland member, i.e. to loosen the gland member. The or each formation may be configured to maintain engagement with the further abutments to release the gland member. The or each further abutment may be arranged on the external surface of the gland member. The or each further abutment may extend in an axial direction. The or each further abutment may extend substantially parallel to an axis of rotation of the gland member.

It may be that the gland member is engageable with a further gland member. The sleeve member may be operable to transmit torque for rotating the gland member relative to the further gland member for tightening the gland member on the further gland member. The sleeve member may be operable to inhibit rotation of the gland member relative to the further gland member for maintaining a tightened position of the gland member and inhibiting loosening of the gland member. The gland member may be engageable with the further gland member by means of mating screw threads.

The sleeve member may be movable in an axial direction relative to the gland member between a release position for rotation with the gland member relative to the further gland member when tightening the gland member and a locking position for engaging both gland members to inhibit relative rotation of the gland member and further gland member.

The method may include, use or provide any of the features of the preceding aspect of the invention.

According to yet another aspect of the invention, we provide a gland nut for a gland assembly, the gland nut being provided with a torque transmitting device to inhibit over-tightening the gland nut.

The gland nut may include, use or provide any of the features of the preceding aspects of the invention.

According to a still further aspect of the invention, we provide a gland assembly for an elongate member extending, in use, through the gland assembly, the gland including two relatively rotatable gland members, and an anti -rotation device operable to inhibit relative rotation of the gland members. By inhibiting relative rotation of the gland members, loosening of the gland members due to vibration or any other reason may be prevented. It may be that efficiency of a seal within the gland is controlled by tightening the gland members and that by preventing loosening of the gland members, the seal efficiency may be maintained.

The anti-rotation device may comprise a sleeve member that is co-operable with both gland members to inhibit relative rotation of the gland members. The sleeve member may fit over and/or around all or part of one or both gland members. The sleeve member may have a hollow body portion. The hollow body portion may receive all or part of one or both gland members.

The sleeve member and a first gland member may have co-operating formations configured to prevent relative rotation therebetween. For example the first gland member may have an external flange of hexagonal or other non-circular form and the sleeve member may have a complementary internal socket in which the flange is received.

The sleeve member and a second gland member may have co-operating formations configured to inhibit relative rotation therebetween. For example one of the sleeve member and the second gland member may have a plurality of axially extending grooves and the other of the sleeve member and the second gland member may have one or more axially extending ribs that are engageable with the grooves.

The co-operating formations may be configured to inhibit relative rotation between the sleeve member and the second gland member if a torque is applied to the sleeve member or the second gland member up to a pre-determined limit. The co-operating formations may be configured to allow relative rotation between the sleeve member and the second gland member if a torque is applied to the sleeve member or the second gland member that exceeds a pre-determined limit.

In one arrangement, the sleeve member may be axially slidable along the second gland member from a release position to a locking position. In the release position the sleeve member is disengaged from the first gland member and relative rotation of the gland members is permitted. In the locking position the sleeve member is engaged with the first gland member and relative rotation of the gland members is inhibited.

In this arrangement, the gland members may be tightened with the sleeve member located in the release position on the second gland member and rotating relative to the first gland member When the gland members have been tightened, the sleeve member may be slid axially to the locking position to engage the first gland member and secure the gland members so that relative rotation of the gland members to loosen the gland members is inhibited. If necessary, the sleeve member may be rotated on the second gland member to align the co-operating formations on the sleeve member and the first gland member such that the sleeve member can be slid axially to the locking position to engage the first gland member and secure the gland members so that relative rotation of the gland members to loosen the gland members is inhibited. In another arrangement, the sleeve member may be located on the first gland member and the second gland member may be rotatable relative to the sleeve member and the first gland member to tighten the gland members by applying a torque sufficient to overcome the engagement of the co-operating formations.

In this arrangement, the gland members may be tightened with the sleeve member located on the first gland member and the second gland member rotating relative to the sleeve member. When the gland members have been tightened, the co-operating formations on the sleeve member and second gland member may engage to inhibit relative rotation of the gland members so that relative rotation of the gland members to loosen the gland members is inhibited.

The sleeve member may also inhibit over-tightening of the gland members in accordance with preceding aspects of the invention. For example, rotation of the sleeve member may be transmitted to one of the gland members for tightening the gland members up to a required degree at which the sleeve member is rotatable relative to said one gland member to prevent over-tightening the gland members whereupon the sleeve member may be axially slidable to engage the other gland member to lock the gland members together and prevent relative rotation of the gland members to loosen the gland members.

According to another aspect of the invention, we provide a method of assembling a gland assembly including connecting two relatively rotatable gland members and providing a device co- operable with both gland members in a tightened condition that inhibits relative rotation of the gland members to loosen the gland members.

By employing a device to inhibit loosening of the gland members in the tightened condition, efficiency of a seal provided by tightening the gland members can be maintained if the gland assembly is exposed to vibration or other forces tending to loosen the gland members.

The method may include, use or provide any of the features of the preceding aspect of the invention.

According to yet another aspect of the invention, we provide a gland nut for a gland assembly, the gland nut being provided with an anti-rotation device to inhibit loosening the gland nut.

The gland nut may include, use or provide any of the features of the preceding aspects of the invention.

According to a still further aspect of the invention, we provide a gland assembly for an elongate member extending, in use, through the gland assembly, the gland including two gland members that are relatively rotatable in a first direction to tighten the gland members and in a second direction to loosen the gland members, and a device operable to control relative rotation of the gland members in the first direction and/or the second direction. It may be that relative rotation of the gland members in the first direction causes a seal member to seal around the elongate member, and the device is operable to inhibit over-tightening the gland members.

It may be that the gland members are engageable by means of mating screw threads whereby rotation of a first gland member by an applied torque in the first direction causes axial movement of the first gland member to tighten the gland member and apply a force to the seal member so as to urge the seal member to seal around the elongate member.

It may be that the device comprises a sleeve member that is rotatable with the first gland member to transmit torque applied to the sleeve member to the first gland member for tightening the gland member.

It may be that the sleeve member fits over and/or around all or part of the first gland member. The sleeve member may have a hollow body portion. The hollow body portion may receive all or part of the first gland member.

It may be that the sleeve member can rotate relative to the first gland member to isolate the first gland member from torque applied to the sleeve member for preventing over-tightening of the gland member.

It may be that the sleeve member has one or more formations arranged to engage the first gland member so that the sleeve member can rotate with the first gland member. In this way, torque applied to the sleeve member can be transmitted to the first gland member for tightening the gland member. The or each formation may be arranged on an internal surface of the sleeve member. The or each formation may extend in an axial direction. The or each formation may extend substantially parallel to an axis of rotation of the gland member.

It may be that the or each formation is capable of deforming to disengage the first gland member so that the sleeve member can rotate relative to the first gland member. In this way, torque applied to the sleeve member is not transmitted to the first gland member for preventing overtightening of the gland member.

It may be that the or each formation is engageable with an abutment on the first gland member for transmitting torque applied to the sleeve member to the gland member. The or each abutment may be arranged on an external surface of the gland member. The or each abutment may extend in an axial direction. The or each abutment may extend substantially parallel to an axis of rotation of the gland member.

It may be that the or each formation is configured to ride over the abutments to prevent overtightening the gland member.

It may be that the or each formation is engageable with a further abutment on the first gland member for transmitting torque applied to the sleeve member to the gland member in the second direction to loosen the gland member. The or each formation may be configured to maintain engagement with the further abutments to release the gland member. The or each further abutment may be arranged on the external surface of the first gland member. The or each further abutment may extend in an axial direction. The or each further abutment may extend substantially parallel to an axis of rotation of the first gland member.

It may be that the or each formation is configured to maintain engagement with the further abutments.

It may be that the sleeve member is operable to inhibit relative rotation of the gland members for maintaining a tightened position of the gland members and inhibiting loosening of the gland members.

The sleeve member may be movable in an axial direction relative to the first gland member between a first position for rotation with the first gland member relative to the second gland member when tightening the gland members, and a second position for engaging both gland members to inhibit relative rotation of the gland members.

The invention further provides a gland assembly as defined in claims 1 to 16 and a method of assembling a gland assembly as defined in claims 17 to 22.

These and other features benefits and advantages of the invention will be apparent from the description hereinafter of embodiments of the invention, provided by way of example only, with reference to the accompanying drawings wherein: -

Figure 1 is a perspective view of a gland assembly according to an embodiment of the invention;

Figure 2 is longitudinal section of the gland assembly of Figure 1 showing the seal member uncompressed;

Figure 3 is a longitudinal section of the gland assembly of Figure 1 showing the seal member compressed;

Figure 4 is a perspective view showing the cap nut and cap nut sleeve of the gland assembly of Figures 1 to 3 disassembled;

Figure 5 is a side view showing the cap nut and cap nut sleeve of Figure 4 assembled;

Figure 6 is a section on the line 6-6 of Figure 5;

Figure 7 is an end view showing the cap nut and cap nut sleeve of Figure 4 assembled;

Figure 8 is a section on the line 8-8 of Figure 7;

Figure 9 is a perspective view showing a modified cap nut and cap nut sleeve disassembled; Figure 10 is a side view showing the cap nut and cap nut sleeve of Figure 9 assembled;

Figure 11 is a section on the line 1 1-1 1 of Figure 10;

Figure 12 is an end view showing the cap nut and cap nut sleeve of Figure 9 assembled; Figure 13 is a section on the line 13-13 of Figure 12; Figure 14 is a perspective view showing another modified cap nut and cap nut sleeve disassembled;

Figure 15 is a side view showing the cap nut and cap nut sleeve of Figure 14 assembled; Figure 16 is a section on the line 16-16 of Figure 15;

Figure 17 is an end view showing the cap nut and cap nut sleeve of Figure 14 assembled;

Figure 18 is a section on the line 18-18 of Figure 17;

Figure 19 is a perspective view showing a further modified cap nut and cap nut sleeve assembled;

Figure 20 is a side view showing the cap nut and cap nut sleeve of Figure 19 assembled; Figure 21 is a section on the line 21-21 of Figure 20;

Figure 22 is an end view showing the cap nut and cap nut sleeve of Figure 19 assembled; Figure 23 is a section on the line 23-23 of Figure 22;

Figure 24 is a perspective view showing yet another modified cap nut and cap nut sleeve disassembled;

Figure 25 is an end view showing the cap nut and cap nut sleeve of Figure 24 assembled;

Figure 26 is a section on the line 26-26 of Figure 25;

Figure 27 is a perspective view of a gland assembly according to another embodiment of the invention;

Figure 28 is a perspective view from one end of the sleeve member of the assembly of Figure 27;

Figure 29 is a perspective view from the other end of the sleeve member of the assembly of Figure 27; and

Figure 30 is a sectional view of the gland assembly of Figure 27.

Referring first to Figures 1 to 8 of the accompanying drawings, a cable gland assembly indicated generally at 1 includes a body 3, a cap nut 5, a cap nut sleeve 7, a seal member 9, and a seal urging member 1 1. Depending on the application, the gland assembly may include other parts such as an adaptor connectable to the body 3 for securing the gland assembly to the wall of an enclosure, a clamping arrangement within the gland assembly for securing cable armour, a barrier sleeve containing a hardenable filler compound within the gland for providing a flameproof seal. These and other features of gland assemblies will be familiar to those skilled in the art and are not described in detail as they do not form part of the present invention. It will be understood that the invention has application to such gland assemblies and the following description is provided by way of non-limiting example of the application of the invention to the gland assembly depicted in the drawings.

The body 3 and cap nut 5 may typically be made of metal, for example brass, although other materials including plastics and metal/plastics composites may be employed. The cap nut sleeve 7 may typically be made of plastics, for example thermoplastics such as acetal (polyoxymethylene), nylon (polyamide), PBT (polybutylene terephthalate), although other materials including metal and metal/plastics composites may be employed. The seal member 9 may typically be made of elastomeric material, for example silicone, neoprene, natural rubber, although other polymeric materials may be employed. The seal urging member 11 may typically be made of plastics, for example thermoplastics such as acetal (polyoxymethylene), nylon (polyamide), PBT (polybutylene terephthalate) although other materials including metal and metal/plastics composites may be employed.

The body 3 preferably has a feature such as a hexagonal flange 13 between the ends for gripping the body 3 with a tool (not shown) such as a spanner. To one side of the flange 13, the body 3 has an externally threaded portion 15 for engagement with an internally threaded portion 17 of the cap nut 5. To the other side of the flange 13, the body 3 may have an externally threaded portion 19 for securing the body 3 to the wall (not shown) of an enclosure, for example a junction box, by inserting the threaded portion 19 through a hole in the wall and attaching a nut (not shown).

The seal member 9 has a body 21, preferably a generally cylindrical body. The body 21 may have an external flange 23 at one end. The body 21 may have an external rib 25 at the other end. The seal urging member 11 has a plurality of fingers 27 extending from a support ring 29. The fingers 27 are preferably arranged in a cylindrical formation on the support ring 29. The seal urging member 11 surrounds the body 21 of the seal member 9. The support ring 29 preferably seats against the external at flange 23 one end of the body 21. The fingers 27 preferably extend to the other end of the body 21 and are preferably provided with a recess 31 in which the external rib 25 at the other end of the body 21 may be located.

Figure 2 shows the cable gland assembly 1 with a cable 33 extending therethrough and the seal member 9 uncompressed and Figure 3 shows the cable gland assembly 1 with the cable 33 extending therethrough and the seal member 9 compressed. The cable 33 may be an electric cable or fibre optic cable. On initial assembly, the flange 23 of the seal member 9 seats against the body 3, preferably against the end of the body 3, and the ends of the fingers 27 seat against the cap nut 5, preferably against an angled internal face 35 of the cap nut 5, with the seal member 9 spaced from the cable 33 as shown in Figure 2.

Each finger 27 is preferably pivotable about the connection to the support ring 29 such that, as the cap nut 5 is screwed onto the body 3, the fingers 27 can pivot inwardly and urge the end of the seal member 9 remote from the flange 23 inwardly to engage and seal around the cable 33 as shown in Figure 3. The fingers 27 are preferably relatively stiff and remain substantially straight while pivoting about the connection to the support ring 23, i.e. the fingers will not bend or flex intermediate their ends. The seal member 9 and the seal urging member 11 are disclosed and claimed in our granted European patent No.1362399 to which the reader is directed for further details. In order to control the degree of tightening of the cap nut 5 and thus the force exerted on the seal member 9 by the cap nut 5 and in turn the pressure exerted on the cable 33 by the seal member 9, the cap nut sleeve 7 is provided. The cap nut sleeve 7 preferably fits over and/or around all or part of the cap nut 5. The cap nut sleeve 7 preferably has a hollow body portion 7a. The hollow body portion 7a preferably receives all or part of the cap nut 5. The cap nut sleeve 7 preferably has a feature such as an external hexagonal form 36 at one end for gripping with a tool (not shown) such as a spanner.

The cap nut sleeve 7 and cap nut 5 preferably have co-operating formations to axially retain the cap nut sleeve 7 on the cap nut 5. For example, the cap nut sleeve 7 may have an internal flange 37 at the same end that locates in an annular groove 39 in the outer surface of the cap nut 5. The flange 37 may be a snap-fit in the groove 39. The cap nut sleeve 7 may be permanently attached to the cap nut 5 by engagement of the co-operating formations. Alternatively, it may be that the cap nut sleeve 7 may be detachable from the cap nut 5.

To one side of the groove 39, the cap nut 5 may have a feature such as an external hexagonal form 41 that is accessible for gripping with a tool (not shown) such as a spanner if required with the cap nut sleeve 7 mounted on the cap nut 5. To the other side of the groove 39, the cap nut 5 may have a plurality of axially extending grooves 43. The grooves 43 may be uniformly spaced apart in the circumferential direction on an external surface of the cap nut 5. The grooves 43 may extend between the groove 39 and the end of the cap nut 5 remote from the hexagonal form 41.

Each groove 43 may have a steep abutment face 45 on one side and a shallow abutment face 49 on the other side. The steep abutment face 45 may extend at approximately 90 degrees to the base 47 of the groove and the shallow abutment face 49 may extend at approximately 45 degrees to the base 47 of the groove 43. These inclinations are not limiting and variations in the inclination of one or both faces 45, 47 can be envisaged.

The cap nut sleeve 7 may have at least one, preferably a plurality, of axially extending fingers 51. The fingers 1 may be uniformly spaced apart in the circumferential direction on an internal surface of cap nut sleeve 7. The fingers 1 may extend between the flange 37 and the end of the cap nut sleeve 7 remote from the hexagonal form 36. The fingers 51 may be inclined with respect to the circumferential direction. Each finger 51 preferably locates in a groove 43 on the cap nut 5 when the cap nut sleeve 7 is mounted on the cap nut 5. The fingers may be inclined at approximately 45 degrees to the circumferential direction. This inclination is not limiting and variations in the inclination of the fingers 51 can be envisaged.

In this embodiment, the cap nut 5 has twenty four (24) axial grooves 43 and the cap nut sleeve 7 has six (6) axial fingers 51. It will be understood that this is not limiting and that the number of grooves 43 and fingers 51 may be varied. Generally, however, it is envisaged that the number of grooves 43 will exceed the number of fingers 51 although this may not be essential and there may be equal numbers of grooves 43 and fingers 51.

In use, the fingers 51 engage the shallow abutment face 49 of the grooves 43 in which they are received to transmit torque from the cap nut sleeve 7 to the cap nut 5 to rotate the cap nut 5 in a direction to tighten the cap nut 5 on the body 3. The torque may be transmitted to tighten the cap nut 5 on the body 3as long as the force required to rotate the cap nut 5 is less than the force required to deform the fingers 51 to ride over the shallow abutment face 49. When the rotational force exceeds the deforming force, the fingers 51 can deform and ride over the shallow abutment faces 49 allowing the cap nut sleeve 7 to rotate around the cap nut 5 so that torque is no longer transmitted from the cap nut sleeve 7 to the cap nut 5 in the direction to tighten the cap nut 5 on the body 3. Deformation of the fingers 51 may be assisted by providing cut-outs 52 in the flange 37 aligned with the fingers 51 such that deformation of the cap nut sleeve 7 may also occur to some extent. As a result, over-tightening of the cap nut 5 can be prevented by the cap nut sleeve 7 slipping relative to the cap nut 5 in the direction to tighten the cap nut 5, i.e. rotation of the cap nut sleeve 7 in the direction of arrow A in Figure 6. If the direction of rotation of the cap nut sleeve 7 is reversed, i.e. rotation of the cap nut sleeve 7 in the direction of arrow B in Figure 6, the tips of the fingers 51 can seat against the steep abutment faces 45 of the grooves 43 in which they are located so that torque is now transmitted from the cap nut sleeve 7 to the cap nut 5 to rotate the cap nut 5 in a direction to loosen the cap nut 5.

As will be apparent, the degree to which the cap nut 5 can be tightened before the cap nut sleeve 7 starts to slip and prevent further tightening of the cap nut 5 will depend on various factors including, for example, the angle of the shallow abutment face 49 on the cap nut 5, the inclination of the fingers 1, the stiffness of the fingers 1, the relative interference between the fingers 51 and grooves 43. Accordingly, by appropriate selection of one or more these factors and/or any other factors affecting transmission of torque between the cap nut sleeve 7 and the cap nut 5, the degree of tightening of the cap nut 5 before slippage occurs can be controlled to prevent the cap nut being overtightened.

Referring now to Figures 9 to 13 of the drawings, there is shown a modification to the cap nut and cap nut sleeve of the first embodiment. For convenience, like reference numerals are used to indicate the same or similar parts. The cap nut sleeve 7 preferably fits over and/or around all or part of the cap nut 5. The cap nut sleeve 7 preferably has a hollow body portion 7a. The hollow body portion 7a preferably receives all or part of the cap nut 5. The cap nut sleeve 7 preferably consists of a strip member 53, for example a belt, provided with formations 55, 7 at the ends that interlock to form the cap nut sleeve 7. In other respects the operation of the cap nut sleeve 7 to control the degree of tightening of the cap nut 5 and to loosen the cap nut 5 is similar to and will be understood from the description of the first embodiment. It may be that the cap nut sleeve 7 may be temporarily attached to the cap nut 5 and can be detached from the cap nut 5. For example the cap nut sleeve 7 may be detached by releasing the formations 55, 57 to open the cap nut sleeve 7 or by sliding the cap nut sleeve 7 in an axial direction relative to the cap nut 5 to disengage the fingers 51 from the grooves 43.

Referring now to Figures 14 to 18 of the drawings, there is shown another modification to the cap nut and cap nut sleeve of the first embodiment. For convenience, like reference numerals are used to indicate the same or similar parts. The cap nut sleeve 7 preferably fits over and/or around all or part of the cap nut 5. The cap nut sleeve 7 preferably has a hollow body portion 7a. The hollow body portion 7a preferably receives all or part of the cap nut 5. The cap nut 5 and cap nut sleeve 7 are preferably provided with equal numbers of grooves 43 and fingers 51. In other respects the operation of the cap nut sleeve 7 to control the degree of tightening of the cap nut 5 and to loosen the cap nut 5 is similar to and will be understood from the description of the first embodiment. It may be that the cap nut 5 does not have an external feature for gripping the cap nut 5 with a tool. It may be that the cap nut sleeve 7 substantially conceals the cap nut 5. The hexagonal form 36 may be provided at the outer end of the cap nut sleeve 7. The cap nut sleeve 7 may be axially retained on the cap nut 5 by engagement of co-operatmg formations such as flange 37 engaging groove 39. The flange 37 may be a snap-fit in the groove 39. The cap nut sleeve 7 may be permanently attached to the cap nut 5 by engagement of the co-operating formations. Alternatively, it may be that the cap nut sleeve 7 may be detachable from the cap nut 5.

Referring now to Figures 19 to 23, there is shown another modification to the cap nut and cap nut sleeve of the first embodiment. For convenience, like reference numerals are used to indicate the same or similar parts. The cap nut sleeve 7 preferably fits over and/or around all or part of the cap nut 5. The cap nut sleeve 7 preferably has a hollow body portion 7a. The hollow body portion 7a preferably receives all or part of the cap nut 5. The cap nut sleeve 7 is preferably located and retained on the cap nut 5 between a pair of annular rings 59 located in annular grooves 61 in the outer surface of the cap nut . In other respects the operation of the cap nut sleeve 7 to control the degree of tightening of the cap nut 5 and to loosen the cap nut 5 is similar to and will be understood from the description of the first embodiment. The cap nut sleeve 7 may be permanently attached to the cap nut 5 by the rings 9. Alternatively, it may be that one or both rings 9 can be released from the associated groove 61 so that the cap nut sleeve 7 can be detached from the cap nut 5 by sliding the cap nut sleeve 7 in an axial direction relative to the cap nut 5

Referring now to Figures 24 to 26, there is shown another modification to the cap nut and cap nut sleeve of the first embodiment. For convenience, like reference numerals are used to indicate the same or similar parts. The cap nut sleeve 7 preferably fits over and/or around all or part of the cap nut 5. The cap nut sleeve 7 preferably has a hollow body portion 7a. The hollow body portion 7a preferably receives all or part of the cap nut 5. The cap nut sleeve 7 is preferably located and retained on the cap nut 5 by an annular ring 63 located in opposed annular grooves 65, 67 in the outer surface of the cap nut 5 and the inner surface of the cap nut sleeve 7. It may be that the axial grooves 43 in the outer surface of the cap nut 5 in the first embodiment are replaced by a plurality of protrusions 69 on an end face of the cap nut 5. The protrusions 69 are preferably spaced apart in the circumferential direction on the end face of the cap nut 5. Each protrusion 69 is preferably provided with a steep abutment face 45 at one end and a shallow abutment face 49 at the other end. It may be that the cap nut sleeve 7 is provided with a plurality of fingers 51 that locate between the protrusions 69. The fingers 51 are preferably inclined similar to the shallow abut faces 49 on the cap nut 5. The fingers 51 preferably co-operate with the shallow abutment faces 49 to transmit torque for tightening the cap nut 5 until the fingers 51 deform and ride over the protrusions 51 to prevent over-tightening the cap nut 5. The fingers 51 preferably co-operate with the steep abutment faces 45 to transmit torque for loosening the cap nut 5.

Referring now to Figures 27 to 30, a cable gland assembly according to another embodiment of the invention is depicted generally at 101 and includes a body 103, a cap nut 105 and a cap nut sleeve 107. The cap nut 105 preferably has an internal thread engageable with an external thread at one end of the body 103 for tightening a seal (not shown) around an elongate member (not shown) extending through the gland assembly in use. The seal may be of the type shown and described with reference to previous embodiments or any other type of seal employed in cable gland assemblies. In this embodiment, an adaptor 109 is shown having an external thread at one end engageable with an internal thread at the other end of the body 103. The adaptor 109 preferably has a spigot 111 at the other end for insertion through a hole (not shown) in a wall of an enclosure (not shown) such as a junction box to which a nut (not shown) may be attached to attach the gland assembly to the enclosure. The adaptor 109 preferably has a feature such as an external flange 113 of hexagonal form for gripping the adaptor 109 with a tool (not shown) such as a spanner. Depending on the application, the gland assembly may include other parts such as a clamping arrangement within the gland assembly for securing cable armour, a barrier sleeve containing a hardenable filler compound within the gland for providing a flameproof seal. These and other features of gland assemblies will be familiar to those skilled in the art and are not described in detail as they do not form part of the present invention.

The body 103, cap nut 105 and adaptor 109 may typically be made of metal, for example brass, although other materials including plastics and metal/plastics composites may be employed. The cap nut sleeve 107 may typically be made of plastics, for example [thermoplastics such as acetal (polyoxymethylene), nylon (polyamide), PBT (polybutylene terephthalate)], although other materials including metal and metal/plastics composites may be employed. The body preferably 103 has a feature such as an external flange 115 of hexagonal form between the ends for gripping the body 103 with a tool (not shown) such as a spanner.

The cap nut sleeve 107 preferably fits over and/or around all or part of the cap nut 105. The cap nut sleeve 107 preferably has a hollow body portion 107a. The hollow body portion 107a preferably receives all or part of the cap nut 105. The cap nut sleeve 107 may have a cylindrical form. An internal socket 117 having a form complementary to the external flange 115 on the body 103 is preferably provided at one end of the cap nut sleeve 107. In this embodiment the flange 115 is hexagonal and the socket 117 has a matching hexagonal profile but it will be understood that other shapes may be employed. The cap nut sleeve 107 is preferably also provided with an internal annular flange 119 that defines the base of the socket 117.

At least one, preferably a plurality, of slots 121 may be formed in the wall of the cap nut sleeve 107. The slots 121 are preferably spaced apart in the circumferential direction. The slots 121 preferably extend in an axial direction from the other end of the cap nut sleeve 107 towards and terminate before the flange 119. Between the slots 121, the cap nut sleeve 107 is preferably provided with one or more internal ribs 123. The ribs 123 are preferably spaced apart in the circumferential direction and extend in an axial direction. The ribs 123 are preferably shorter than and terminate before the inner end of the slots 121.

The cap nut 105 preferably has a feature such as an external hexagonal form 125 at one end for gripping with a tool (not shown) such as a spanner and a plurality of grooves 127 extending axially to the other end. The grooves 125 may be uniformly spaced apart in the circumferential direction. Each rib 123 is preferably received in a groove 127 when the cap nut sleeve 107 is mounted on the cap nut 105. In this embodiment, the number of grooves 125 exceeds the number of ribs 123 although this may not be essential and there could be equal numbers of ribs 123 and grooves 125.

In use, the cap nut sleeve 107 is mounted on the cap nut 105 with the flange 119 located against the end of the cap nut 105. The cap nut 105 is attached to the body 103 by engagement of the matching screw threads and rotated by engagement of the hexagonal form 125 with a tool to urge a seal (not shown) located between the body 103 and cap nut 105 to engage an elongate element (not shown) such as a cable extending axially through the gland. When the cap nut 105 has been sufficiently tightened to achieve the required seal, the cap nut sleeve 107 can be slid in an axial direction to locate the hexagonal flange 115 in the socket 117 as shown in Figure 30. If necessary, the cap nut sleeve 107 can be rotated relative to the cap nut 105 to align the socket 117 with the flange 115, for example by applying a rotational force in a clockwise or anti-clockwise direction to the cap nut sleeve 107 sufficient to deform the slotted end of the cap nut sleeve 107 so that the ribs 123 can disengage the grooves 127 allowing the cap nut sleeve 107 to rotate and engage the ribs 123 in the adjacent grooves 127 until the socket 117 is aligned with the flange 115. The cap nut sleeve 107 can then be slid to engage the flange 115 in the socket 117. In this position, the ribs 123 are still received in the grooves 125 and the cap nut sleeve 107 extends between and engages both the body 103 and cap nut 105 so that rotation of the cap nut 105 relative to the body 103 is inhibited. As a result, loosening of the cap nut 105 by vibration or other forces applied to the gland assembly in situ is inhibited and may be prevented entirely. If it is necessary to dis-assemble the gland for any reason, the cap nut sleeve 107 can be slid back towards the cap nut 105 to disengage the flange 115 from the socket 117 and the cap nut 105 unscrewed from the body 103.

In the above-described embodiment, the cap nut 105 and cap nut sleeve 107 are configured so that the cap nut sleeve 107 can be rotated in either direction relative to the cap nut 105 to align the socket 117 with the flange 115 and the cap nut sleeve 107 provides the function of an anti-rotation device operable to inhibit relative rotation of the cap nut 105 and body 103 when positioned to engage both the cap nut 105 and body 103. It will be understood, however, that cap nut 105 and cap nut sleeve 107 may also be configured so that the cap nut sleeve 107 combines the function of the anti- rotation device with the function of a torque transmitting device operable to control tightening of the cap nut 105 as described for the previous embodiments.

Thus the cap nut sleeve 107 may be provided with a feature such as an external hexagonal form for gripping the cap nut sleeve 107 with a tool such as a spanner and the ribs 123 and grooves 125 configured to transmit torque applied to the cap nut sleeve 105 to the cap nut 105 for tightening the cap nut 105 on the body 103 until the required degree of tightening is obtained whereupon the slotted portions deform allowing the cap nut sleeve 107 to rotate relative to the cap nut 105 to prevent further tightening of the cap nut 105 on the body 103. This rotation may also allow the socket 117 to be aligned with the flange 115 so that the cap nut sleeve 107 can be slid to engage the flange 115 and inhibit relative rotation between the cap nut 105 and the body 103 to loosen the cap nut 105. The ribs 123 and grooves 125 may also be configured to maintain engagement and transmit torque applied to the cap nut sleeve 107 in the reverse direction to the cap nut 105 for releasing the cap nut 105 when the cap nut sleeve 107 is positioned to disengage the body 103. It will be understood that the cap nut and cap nut sleeve may be provided with any suitable formations for achieving the required operation of the cap nut sleeve.

While the invention has been described with reference to exemplary embodiments, it will be understood that we do not intend the invention to be limited thereto and that various modifications and changes may be made without departing from the principles and concepts of the invention.

For example, the cap nut and cap nut sleeve may be provided with any suitable co-operating formations capable of providing one or more of the following functions

• transmitting torque in one direction of rotation for tightening the cap nut to a required degree · allowing the cap nut sleeve to slip relative to the cap nut to prevent over-tightening the cap nut

• transmitting torque in the reverse direction of rotation for loosening the cap nut

• allowing the cap nut sleeve to engage the cap nut and another gland part to prevent loosening the cap nut

In at least some of the above-descnbed embodiments, the cap nut sleeve is provided with one or more fingers for transmitting torque to the cap nut where the or each fmger is capable of deforming to allow the cap nut sleeve to slip over and rotate relative to the cap nut to prevent over-tightening the cap nut and thus control the pressure exerted on the seal member and in turn control the contact pressure between the seal member and the cable. In other arrangements, it may be that one or more fingers (or other suitable formation(s)) are provided on the cap nut, for example where the cap nut is made of plastics or a metal/plastics composite. In this case, the cap nut sleeve may be made of metal or a metal/plastics composite or plastics.

In at least some of the above-described embodiments, the seal member is provided with a seal urging device to urge the seal member to engage the cable in response to movement of the cap nut. In other arrangements, it may be that the seal member and seal urging device are replaced by any other suitable seal arrangement responsive to movement of the cap nut to engage the cable.

It will also be understood that the principles and concepts of the invention are not limited to the exemplary embodiments of a cable gland assembly. The provision of the cap nut sleeve configured to prevent over-tightening of the cap nut and/or to prevent loosening of the cap nut may be applied to any threadably engaged parts of a gland assembly. The gland assembly may have a seal of any type that is urged to engage an elongate member extending through the gland in response to relative rotation of two parts of the gland assembly.

For example, the invention has application including but not limited to

• gland assemblies for armoured electric cable or fibre optic cable or pipes or conduits

• gland assemblies for non-armoured electric cable or fibre optic cable or pipes or conduits

• barrier gland assemblies for electric cable or fibre optic cable or pipes or conduits

· non-barrier gland assemblies for electric or fibre optic cable or pipes or conduits

Other modifications and changes that can be made without departing from the principles and concepts described herein will be apparent to those skilled in the art and are covered herein.

It will also be understood that the invention extends to and includes any novel feature or combination of novel features described herein.

An embodiment provides a gland assembly for an elongate member extending, in use, through the gland assembly, the gland assembly including a gland member that is movable in response to an applied torque to cause a seal member to seal around the elongate member, wherein the gland member is provided with a torque transmitting device operable to inhibit over-tightening the gland member.

The gland member may be engageable with a further gland member by means of mating screw threads whereby rotation of the gland member by an applied torque in one direction causes axial movement of the gland member to tighten the gland member and apply a force to the seal member so as to urge the seal member to seal around the elongate member. The torque transmitting device may comprise a sleeve member that is rotatable with the gland member to transmit torque applied to the sleeve member to the gland member for tightening the gland member. The sleeve member may rotate relative to the gland member to isolate the gland member from torque applied to the sleeve member for preventing over-tightening of the gland member. The sleeve member may have at least one formation arranged to engage the gland member so that the sleeve member can rotate with the gland member whereby torque applied to the sleeve member is transmitted to the gland member for tightening the gland member. The at least one formation may be capable of deforming to disengage the gland member so that the sleeve member can rotate relative to the gland member whereby torque applied to the sleeve member is not transmitted to the gland member for preventing over-tightening of the gland member. The at least one formation may be engageable with an abutment on the gland member for transmitting torque applied to the sleeve member to the gland member. The at least one formation may be configured to ride over the abutments to prevent over-tightening the gland member. The at least one formation may be engageable with a further abutment on the gland member for transmitting torque applied to the sleeve member to the gland member in a direction to loosen the gland member. The at least one formation may be configured to maintain engagement with the further abutments to release the gland member. The sleeve member may be operable to inhibit rotation of the gland member relative to the further gland member for maintaining a tightened position of the gland member and inhibiting loosening of the gland member. The sleeve member maybe movable in an axial direction relative to the gland member between a release position for rotation with the gland member relative to the further gland member when tightening the gland member and a locking position for engaging both gland members to inhibit relative rotation of the gland member and further gland member.

An embodiment provides a method of assembling a gland assembly to control a force exerted on a seal member by a gland member that is movable in response to an applied torque to tighten the gland member and cause the seal member to seal around an elongate member extending through the gland assembly, the method including providing the gland member with a device for transmitting an applied torque to the gland member for tightening the gland member wherein the device is configured to inhibit over-tightening the gland member.

The torque transmitting device may be configured to rotate with the gland member in a direction to tighten the gland member to a required degree and then to rotate relative to the gland member so that over-tightening of the gland member can be avoided. The torque transmitting device may comprise a sleeve member that can be fitted over the gland member. The sleeve member may be provided with at least one formation engageable with the gland member for transmitting torque applied to the sleeve member to the gland member for tightening the gland member, wherein the at least one formation may deform when the gland member has been tightened to the required degree to permit the sleeve member to rotate relative to the gland member.

An embodiment provides a gland nut for a gland assembly, the gland nut being provided with a torque transmitting device to inhibit over-tightening the gland nut. An embodiment provides a gland assembly for an elongate member extending, in use, through the gland assembly, the gland including two relatively rotatable gland members, and an anti-rotation device operable to inhibit relative rotation of the gland members.

The anti-rotation device may comprise a sleeve member that is co-operable with both gland members to inhibit relative rotation of the gland members. The sleeve member and a first gland member may have co-operating formations configured to prevent relative rotation therebetween. The first gland member may have an external flange and the sleeve member may have a complementary internal socket in which the flange is received to prevent relative rotation of the first gland member and sleeve member. The sleeve member and a second gland member may have co-operating formations configured to inhibit relative rotation therebetween. One of the sleeve member and the second gland member may have a plurality of axially extending grooves and the other of the sleeve member and the second gland member has at least one axially extending rib engageable with the grooves. The co-operating formations may be configured to inhibit relative rotation between the sleeve member and the second gland member if a torque is applied to the sleeve member or the second gland member up to a pre-determined limit, and to allow relative rotation between the sleeve member and the second gland member if a torque is applied to the sleeve member or the second gland member that exceeds a pre-determined limit. The sleeve member may be axially slidable along the second gland member from a release position to a locking position. In the release position, the sleeve member may be disengaged from the first gland member and relative rotation of the gland members is permitted. In the locking position, the sleeve member may be engaged with the first gland member and relative rotation of the gland members is inhibited. The gland members may be tightened with the sleeve member located in the release position on the second gland member and rotating relative to the first gland member. When the gland members have been tightened, the sleeve member may be slid axially to the locking position to engage the first gland member and secure the gland members so that relative rotation of the gland members to loosen the gland members is inhibited. The sleeve member may be located on the first gland member and the second gland member is rotatable relative to the sleeve member and the first gland member to tighten the gland members by applying a torque sufficient to overcome the engagement of the co-operating formations on the sleeve member and the second gland member. The co-operating formations on the sleeve member and second gland member may engage to inhibit relative rotation of the gland members so that relative rotation of the gland members to loosen the gland members is inhibited. The sleeve member may inhibit over-tightening of the gland members.

An embodiment provides a method of assembling a gland assembly including connecting two relatively rotatable gland members and providing a device co-operable with both gland members in a tightened condition that inhibits relative rotation of the gland members to loosen the gland members. An embodiment provides a gland nut for a gland assembly, the gland nut being provided with an anti-rotation device to inhibit loosening the gland nut.

An embodiment provides a gland assembly for an elongate member extending, in use, through the gland assembly, the gland including two gland members that are relatively rotatable in a first direction to tighten the gland members and in a second direction to loosen the gland members, and a device operable to control relative rotation of the gland members in the first direction and/or the second direction.

Relative rotation of the gland members in the first direction may cause a seal member to seal around the elongate member, and one of the gland members may be provided with a device operable to inhibit over-tightening the gland members. The gland members may be engageable by means of mating screw threads whereby rotation of said one gland member by an applied torque in the first direction causes axial movement of said one gland member to tighten the gland member and apply a force to the seal member so as to urge the seal member to seal around the elongate member. The device may comprise a sleeve member that is rotatable with said one gland member to transmit torque applied to the sleeve member to the gland member for tightening the gland member. The sleeve member may rotate relative to said one gland member to isolate the gland member from torque applied to the sleeve member for preventing over-tightening of the gland member. The sleeve member may have at least one formation arranged to engage said one gland member so that the sleeve member can rotate with the gland member whereby torque applied to the sleeve member is transmitted to the gland member for tightening the gland member. The at least one formation may be capable of deforming to disengage said one gland member so that the sleeve member can rotate relative to the gland member whereby torque applied to the sleeve member is not transmitted to the gland member for preventing over-tightening of the gland member. The at least one formation may be engageable with an abutment on said one gland member for transmitting torque applied to the sleeve member to the gland member. The at least one formation may be configured to ride over the abutment to prevent over-tightening the gland member. The at least one formation may be engageable with a further abutment on said one gland member for transmitting torque applied to the sleeve member to the gland member in the second direction to loosen the gland member. The at least one formation may be configured to maintain engagement with the further abutments The sleeve member may be operable to inhibit relative rotation of the gland members for maintaining a tightened position of the gland members and inhibiting loosening of the gland members. The sleeve member may be movable in an axial direction relative to said one gland member between a first position for rotation with said one gland member relative to the other gland member when tightening the gland members and a second position for engaging both gland members to inhibit relative rotation of the gland members.