The invention is particularly suitable for use with coiled elements in the form of coiled service supply lines such as are used on articulated vehicles for providing connections between the traction vehicle (cab) and the trailer.

Typically the service lines comprise electrical power supply cables and pneumatic and/or hydraulic lines, e. g. for supply of compressed air from a source associated with the cab to the braking system of the trailer.

The service lines are produced in a coiled form to allow them to accommodate for variations in distance between the connection points on the cab and the trailer as this distance can vary significantly as the trailer orientation varies from an in- line position and extreme angular positions relative to the cab during turning and tight manoeuvring. Also, the service lines are required to contract to a relatively small size when the cab is not coupled up to the trailer.

A drawback with coiled service lines is that usually two or more (e. g. six) are connected to the cab and when it becomes necessary to couple a trailer to the cab, they are invariably tangled up with each other and time is spent untangling them for connection to the appropriate points on the trailer.

Often a driver, after executing tight turning manoeuvres in a restricted space, will check that whether the service lines have become tangled and untangle them if necessary before proceeding further. In this context, tangled service lines are liable to

be unduly stressed during vehicle manoeuvring, possibly causing kinking and damage to the service lines. In the case of air supply lines, this can for instance lead to rupture of the air line with consequent loss of air supply to the trailer braking system, giving rise to a potential road safety hazard through locking of the trailer brakes.

The problems are compounded by the fact that the coiled service lines are often covered in grease and grime and are therefore awkward and messy to handle.

According to one aspect of the present invention there is provided a coiled service line for use for example in providing electrical, hydraulic and/or pneumatic connections between a traction vehicle and trailer, the service line being provided with an anti-tangling element or elements capable of expanding and contracting with the coiled service line so as to prevent tangling together of service lines in use.

The anti-tangling elements may be afforded by a tubular sleeve which is in nested relation with the service line (usually with the sleeve receiving the service line), the sleeve being expansible and contractible with the coil.

According to a second aspect of the present invention there is provided a coiled service line for use for example in providing electrical, hydraulic and/or pneumatic connections between a traction vehicle and trailer, the service line being provided with a tubular sleeve receiving the coil, the sleeve being expansible and contractible with the coil.

The anti-tangling element or sleeve may be provided with an opening or openings in the tubular wall thereof.

The opening or openings may enlarge and close up in response to expansion and contraction respectively of the anti-tangling element or sleeve.

There may be a large number of such openings so that the anti-tangling element or sleeve is of openwork structure. Such an arrangement may be particularly advantageous in terms of weight reduction. If desired, the openings may be confined to a localised region of the anti-tangling element or sleeve, e. g. approximately midway along its length, so that the weight reduction is greatest that region corresponding to the lowermost section of the sagging profile assumed by the service line in use, i. e. as a result of the tendency for the service line to sag between its points of connection to the tractor and trailer.

The anti-tangling element or sleeve may be formed with means for draining any water that may, in use, collect in use. Such drainage means may comprise one or more apertures in the wall of the sleeve, the aperture or apertures preferably being provided at a location or locations intermediate the end regions of the sleeve with at least one aperture being provided at a location approximately midway between the end regions of the sleeve so that, in use of the sleeve/service line on a tractor/trailer combination, water collecting in the lower region of the sagging sleeve/service line can drain from the sleeve at such lower region.

The aperture or apertures may be of helical configuration in which case the sense of the helix may be opposite to that of the coiled service line.

One or more fastening elements may be provided for fixing the opposite ends of the sleeve relative to opposite ends of the service line. Such fastening elements may be arranged to secure the sleeve to the service line.

The sleeve may be in close fitting relation with the coil so that coil expansion and contraction is accompanied by sleeve expansion and contraction. If desired, the sleeve may be fastened to the coil at one or more locations.

The anti-tangling element or sleeve desirably has some degree of resilience so as to be self-contractible, typically so that when extended and then allowed to self- contract, it is capable of self-contracting by at least 50% of the extension.

The anti-tangling element or sleeve is conveniently made of a plastics material and may comprise a composite material such as a layer of textile material combined with or coated with a layer of plastics material. Such composite materials are often used in the fabrication of hose-type products.

In its fully expanded condition, the length of the anti-tangling element or sleeve is at least twice it fully contracted condition. Typically, in its fully expanded condition, the length of the anti-tangling element or sleeve is at least three, preferably at least four and more preferably at least five, times its fully contracted condition.

The anti-tangling element or sleeve in its fully contracted condition may be less than 36, typically less than 24 inches in length, e. g. less than 18 inches in length.

The anti-tangling element or sleeve may be of an openwork or net-like structure (e. g. an extruded plastics netting), particularly when expanded.

According to another aspect of the present invention there is provided a vehicle comprising a traction vehicle and a trailer with at least one coiled service line which extends between the traction vehicle and the trailer and is provided with an anti- tangling element or elements capable of expanding and contracting with the service line

while preventing tangling together of that service line with an adjacent service line or lines.

Anti-tangling may be achieved by provision of an element or elements which serve to bridge the gaps present between the coil convolutions of a service line in use thereby preventing entry of the coils of one service line into the gaps between the coils of another service line to such an extent that the two service lines become entangled with each other.

The vehicle may be provided with two or more service lines each of which is provided with an anti-tangling element or elements as aforesaid.

The anti-tangling elements may if desired be physically connected or united with, e. g. integrally formed with, the service line.

For instance, the service line may have an outer layer or sleeve and the anti- tangling elements may be connected to or integrally formed (e. g. by moulding or by bonding techniques such as heat bonding, ultrasonic welding, friction welding etc) with the outer layer or sleeve in such a way that the anti-tangling elements can accommodate expansion and contraction of the service line while bridging the gaps between the coil convolutions so as to prevent adjacent service lines becoming entangled with each other in use.

Typically the outer layer or sleeve of the service line is made of a plastics material and the anti-tangling elements are of the same plastics material, being arranged to extend between and connected to the outer layer or sleeve of the service line to bridge the gaps between adjacent coil convolutions.

There may be one or more anti-tangling elements extending between each pair of adjacent convolutions of the service line. The anti-tangling elements may for instance comprise a network of strands and the strands may be linked together, e. g. in the manner of a net-like structure, such as an extruded plastics netting..

The anti-tangling element (s) may be external to, or otherwise associated with, the service line. For instance, the anti-tangling element (s) may be located internally of the service line (or at least inboard of an imaginary cylinder coinciding with the outer periphery of the coil convolutions) and/or between the coil convolutions of the service line.

Each anti-tangling element may extend between locations on successive coils which are circumferentially offset from each other so that, when the service line is substantially fully contracted, the anti-tangling elements extend in a predominantly circumferential direction relative to the central axis of the service line (about which the coil convolutions extend generally circumferentially). Thus, when the service line is extended significantly, the anti-tangling elements become re-orientated and extend predominantly parallel to the central axis of the service line.

The anti-tangling elements are preferably flexible so that they may fold when the service line is contracted and straighten out when the service line is expanded.

The arrangement may be such that the folded elements extend generally circumferentially when the service line is substantially fully contracted, or alternatively such that they extend outwardly or inwardly of the coiled service line when latter is substantially fully contracted.

Each anti-tangling element may be connected to the service line at any point around the outer periphery of the service line as seen in cross-section. For example, each

anti-tangling element may extend between points on adjacent convolutions that are located internally or externally relative to the fully contracted coiled service line or each element may extend between points which would touch if the service line is fully contracted.

The anti-tangling elements may comprise strands of material, preferably a flexible and/or foldable material such as a plastics material or a composite material (e. g. textile/plastics). Such strands may for example be generally round in cross-section or they may be in the form of strips.

The anti-tangling elements may be provided by a tubular sleeve which is in nested relation with the service line.

The anti-tangling elements associated with the or each service line may be provided by a sleeve as defined hereinabove.

In one embodiment of the invention the sleeve may be of a flexible net-like material or of a flexible tubular openwork structure, such as webbing, so as to allow the sleeve to be expanded and contracted, e. g. to the extent mentioned above.

Such a sleeve may be produced in any convenient manner; for instance, it may be woven from strands of material or it may be a sheet material formed with an array of slits or elongate openings extending generally circumferentially with respect to the longitudinal axis of the tubular sleeve.

The sleeve in this instance may comprise an array of elongate strands interconnected by nodes such that, in a substantially contracted condition of the sleeve, the strands extend primarily laterally of the longitudinal axis of the sleeve and, in a

substantially fully extended condition of the sleeve, they extend primarily axially relative to said longitudinal axis.

The nodes may be arranged in substantially circumferentially aligned groups with usually no less than 3 and no more than 5 nodes in each such group, 4 nodes per group being preferred.

In this embodiment of the invention, the sleeve may comprise a sheet material formed with an array of slits which extend generally circumferentially of the longitudinal axis of the sleeve and open up to allow expansion of the sleeve.

The slits may be arranged in circumferentially aligned groups with a node between successive slits and the slits in each group are desirably offset with respect to the groups of slits extending along each side thereof. The degree of offset is typically such that each node separating the slits in one group lies substantially midway along the length of the slits in the bordering groups.

The invention may also be implemented by means of an expansible sleeve in the form of a flexible hose which is capable of expanding and contracting with the service line.

The hose may be so configured that it can be extended from a substantially fully axially contracted condition to a length which is in excess of twice (e. g. at least three, four or even five times) its fully contracted condition.

The hose may be of substantially the same or similar design to the form of flexible hose that is used for example in conjuction with clothes drying machines for the purpose of exhausting moisture laden air from the machine.

The wall of the hose may be provided with one or more apertures for drainage purposes, as mentioned above. The hose wall may be provided with a large number of apertures so that it is of openwork structure thereby reducing the weight of the hose. If desired, the apertures may be confined to a localised region of the hose, e. g. to that region which will be lowermost in use as a result of the service lines tending to sag between their points of connection to the tractor and trailer.

The hose may for instance comprise a helical wire or like element linked or sheathed with a plastics material of tubular configuration which is sufficiently flexible to expand and contract over the full range of expansion and contraction that the service line undergoes in use when installed between the truck and trailer of an articulated vehicle.

The material forming the sheath will typically be suitably tough and durable so as to withstand constant expansion and retraction and also the abrasion that it may be subjected to during use in conjunction with a service line.

The hose, e. g. through the helical coil, may have some degree of resilience such that it will tend to self contract, i. e. close up towards the contracted condition when not subject to extension forces.

The helical coil may be a coil of a design similar to the type commonly used as a child's walking spring toy and known under the name"Slinky"but suitably designed for use with a coiled service line.

The coiled material may be in the form of coiled wire or strip, e. g. metal wire or a plastics strip. The material from which the coil is formed may be round in cross-section or it may be of other cross-sectional shape such as square or rectangular.

The thickness of the coiled material is typically substantially less than the cross-sectional diameter of the coiled service line. For instance, the thickness of the material forming the helical coil of the sleeve may be less than the diameter of the service line it is associated with by a factor of at least 50%, e. g. by a factor of at least 75% and typically at least 100%.

Irrespective of the particular configuration of the sleeve used (viz. openwork or hose type), it may be a close fit to the service line or it may be a relatively loose fit and, in both cases, the sleeve and/or the service line may be provided with one or more fasteners for coupling the two together so that, as the service line, lengthens and contracts, the expansible sleeve lengthens and contracts with it. For instance, there may be fasteners at least at or adjacent each end of the sleeve and possibly also fasteners at a location or locations intermediate the ends of the sleeve.

Although the service line is normally inserted into the expansible sleeve, the possibility is not excluded of the expansible sleeve or other element being otherwise associated with the service line so as to prevent tangling.

The anti-tangling element (s), e. g. an expansible sleeve, may be located externally or internally of the coiled service line. At least one or at least some of the anti- tangling elements may be located internally of the coiled service line.

In a further implementation of the invention, the anti-tangling element (s) may comprise a helical coil which may, but need not necessarily, be linked or sheathed with a plastics material of tubular configuration and the helical coil may have any one or more of the features referred to above. For instance, the anti-tangling element may comprise a helically extending strip of plastics material, e. g. nylon, forming a sleeve in

which the service line may be received. Where the anti-tangling element (s) are of a helical configuration, the sense of the helix may be opposite to that of the coiled service line.

The anti-tangling element may, in another implementation of the invention, be in the form of a woven or braided sleeve in which the filaments or other woven/braided elements allow the sleeve to be contracted and expanded in its lengthwise direction. The sleeve may be braided or woven in such a way that it is contracted when relaxed and, when expanded, tends to revert to its contracted state if allowed to relax.

The anti-tangling element (s), irrespective of how implemented, may be coupled, e. g. by fasteners, to the coiled service line so that the element (s) in use can expand and contract with the service line. The coupling means may be normally carried by the anti-tangling element (s) and/or by the service line and designed for engagement with the other component.

Where, in any of the forms that the invention may take, coupling means are used to secure the anti-tangling element to the coiled service line, the coupling means may comprise so-called cable ties for linking the anti-tangling element to the service line at one or more points along the length of the latter.

The coupling means, e. g. cable ties, may be releasable or non-releasable.

Usually the cable ties will be located at or adjacent the ends of the anti-tangling element (s) and optionally at one or more locations intermediate the ends of the latter.

The cable ties may be linked to the anti-tangling element (s) so that, in use, the anti-tangling element may first be fitted in nested relation with the service line and then secured thereto by looping the cable ties around the convolutions of the service line.

The cable ties may be linked to the anti-tangling element during the production of the latter and prior to assembly to the service line. Alternatively the anti-tangling element (s) and cable ties may be supplied as a kit with the cable ties being separate from the anti- tangling element (s). In the latter event, the anti-tangling element (s) may be manufactured with linkage points such as apertures by means of which the cable ties can be coupled thereto during assembly of the anti-tangling element (s) to the service line.

Each cable tie may for instance comprise a one-piece cable tie including a flexible strap having a row of teeth thereon and a frame integral with one end thereof and a strap-receiving opening therethrough, there being a pawl hingedly mounted on the frame for engagement with the teeth so as to allow movement of the strap in one direction through the opening but prevent movement in the opposite direction until the pawl is moved to a strap-releasing position.

Although the anti-tangling element (s) may be provided over substantially the entire length of the service line, the possibility is not excluded of the anti-tangling element (s), however, implemented, being located at one or more strategic points along the length of the service lines, particularly at locations where the service lines are more prone to become entangled.

The anti-tangling element (s) may typically be designed so as to follow the contour of the service line in use. For instance, the service lines when in use are coupled at each end to a truck and trailer respectively and will tend to sag over their unsupported span extending between such connections. The anti-tangling element, e. g. an expansible sleeve, of the present invention may be sufficiently flexible that sagging of the service lines is not unduly impeded in use, i. e. the sleeve or other element (s) may flex and follow the contour taken up by the sagging service line. Also, it is preferred that the anti-

tangling element (s) should be lightweight so that they do not cause the service lines to sag to a significantly greater extent than they would otherwise do in the absence of the anti-tangling element (s).

Where the anti-tangling element (s) comprise (s) a helical component, the latter may be fitted to the service line in such a way that the sense of the helix corresponds to, or is opposite to, that of the helically coiled service line.

The invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a diagrammatic plan view showing a coiled service line connected between a tractor and trailer of an articulated vehicle, the extent of articulation and the effect on the service line being depicted in phantom outline; Figure 2 illustrates a sheet of material from which a sleeve in accordance with the invention is fabricated; Figure 3 is a view showing expansion of part of the sleeve, a coiled service line being shown diagrammatically in outline; and.

Figure 4 is a diagrammatic view of a pair of service lines, one of which is provided with an anti-tangling element according to the present invention.

Referring firstly to Figure 1, an articulated vehicle comprising a cab 1 and trailer 2 has a number of helically coiled service lines 3 (commonly referred to as "suzies") connected between the cab and trailer, the service lines being in close proximity with each other whereby they tend to tangle with each other in use. For simplicity, only one service line is illustrated in Figure 1. The normal position of the cab and trailer combination are shown in full outline while the trailer 2 in an articulated position is shown in phantom outline. The service line 3 is shown in its contracted state (full outline) and its extended state (phantom outline). In Figure 1, an anti-tangling element in the form of an expansible tubular sleeve 4 is also illustrated and it will be seen that this is arranged to contract and expand with the service line. A number of fasteners (not shown) serve to couple the tubular sleeve 4 to the service line 3 at opposite ends thereof. Alternatively, instead of being fastened directly to the service line 3, the ends of the sleeve may be fixed in relation to the ends of the service line by coupling the sleeve at or adjacent the ends thereof to suitable anchorage points on the cab 1 and trailer 2 respectively.

Referring to Figure 2, an anti-tangling element in accordance with one embodiment of the invention may be fabricated as a sleeve from a sheet 10 of flexible material. The sheet 10 is rectangular having long edges 12 and short edges 14. The sheet can be formed into a tubular sleeve by folding it to bring together its long edges 12 and securing them together at those edges. The edges 14 are left free to provide openings at each end of the sleeve so formed. The tubular sleeve may then be slipped over a coiled supply line (a so-called"suzy") so as to prevent a number of lines becoming entangled with each other in use.

The length of the sleeve as initially formed may correspond to the contracted length of the coiled service lines with which it is to be used and its diameter may correspond to the coil diameter. Thus, the length of the long edges 12 may range from 12 to 14 inches upwards, typically of the order of 18 to 24 inches, while the length of the short sides will be such that the diameter of the resulting tubular sleeve is typically of the order of 4 to 8 inches. However, the contracted length of the sleeve need not necessarily correspond to the length of the coiled section of the supply line; e. g it may be longer in which case means may be provided for fastening the sleeve to the coiled service line, usually at or adjacent the open ends of the sleeve. Also the sleeve may, if desired, be a relatively loose fit around the coiled service line and, in this instance also, means may be provided for fastening the sleeve to the coiled service line, usually at or adjacent the open ends of the sleeve. Thus, a suzy having a diameter of 112 mm and a sleevable length of 14 inches in the contracted condition may be fitted with a sleeve 24 inches in length and having a diameter of say 120 mm. The sleeve can then be readily pulled over the contracted service line which would then be expanded by about 10 inches within the sleeve and clipped or otherwise fastened to the sleeve.

Examples of coiled service lines with which the sleeve may be used include those produced by the manufacturers Euroflex and Abal. These service lines for instance typically have a contracted length of about 24 inches and upwards (including end fittings) of which about 14 inches (and upwards) comprises a sleevable length constituted by the coil convolutions. The diameter of these service lines when in the contracted condition is typically about 100/115 mm.

The sleeve is required to accommodate extension of the coiled services lines and must therefore be capable of longitudinal expansion well in excess of its original length (i. e. the length of the long sides 12). To allow this to be achieved, in the illustrated

embodiment the sleeve is formed with an array of slits extending through the thickness of the sheet material, the slits 16 being arranged in generally parallel rows 18 of slits extending between the long edges of the sheet 10 and hence generally circumferentially around the axis of the tubular sleeve formed from the sheet 10. The slits are all of substantially the same length.

The slits in each row 18 are generally aligned with one another and are spaced from each other by nodes 20. The slits of each row are offset relative to those in the adjacent rows so that nodes 20 in one row lie approximately midway along the length of the slits on each side. Thus, the node depicted 20a in row A lies midway between the ends of slits 16b and 16c of rows B and C.

The slits in alternate rows terminate short of the long edges (see for instance row D) while the other rows (e. g. E) include slits which extend to, and are open at, the long edges. In this way, short sections 22 of the long edges are uninterrupted by the slits 16 so that the long edges of the sheet material can be united by bringing together the short sections along one long edge and the short sections along the other long edge and securing together each short section 22 with a respective short section 22 at the opposite edge of the sheet. Thus, for example, in forming the tubular sleeve, short section 22a would be connected to short section 22b. However, the possibility of staggering the short sections, e. g. connection of short section 22a with short section 22c, is not excluded. In this way, those slits which open at the long edges 12 are registered with one another, e. g. half-length slits 16e and 16f will register with each other to form a full length slit.

From the foregoing, it will be seen that each slit, whether a full length slit or one formed by two half length slits, is bounded on each side by strands of material and

at each end by nodes (see for instance, slit 16g bounded by strands 20g and 20h and by nodes 20g and 20h). Typically the strands have a width of about 5 mm and the slits are about 6 to 7 cms in length. However, these dimensions will in practice be varied according to requirements. For example, for a given slit length, a sleeve fabricated with 200 strands having a width of 2 mm will tend to have greater extensibility than one fabricated with 80 strands of 5 mm width.

As will be understood from Figure 2, when the sheet is formed into the tubular sleeve, there will be four slits 16 in each row and hence four nodes. This is the presently preferred arrangement since with fewer slits, the strands 24 may tend to become trapped between the coil convolutions and will also be less effective in preventing the convolutions of one coiled line tangling with those of an adjacent coiled line. Although there may be more than four slits in a row, as the number increases this will tend to reduce the extent to which the sleeve can expand.

By slitting the sheet in this manner, the resulting sleeve can be expanded to a considerable extent in a direction parallel to the axis of the sleeve, i. e. parallel to the long edges 12, such expansion being permitted as a result of the slits opening up in the manner illustrated by a portion of the sleeve as shown on an enlarged scale in Figure 3 which also illustrates in phantom outline the extended coiled service line 30, e. g. an air supply line or electrical cable. It will be seen that, when expanded, the sleeve forms a net-like structure or webbing around the service line to prevent the coils of adjacent services lines becoming entangled with each other.

Referring to Figure 3, expansion of the sleeve in the longitudinal direction is accompanied by expansion of the slits 16 to form openings 26 bordered by the now

distorted strands 24 and nodes 20. In Figure 3, the direction of expansion is indicated by arrow X which is generally parallel with the axis of the sleeve. In the contracted condition of the sleeve, the strands 24 extend primarily circumferentially but as the sleeve expands longitudinally the strands separate and distort and take on a component of extension axially of the sleeve and may eventually primarily extend in that direction.

Although in Figure 3, the strands 24 are shown distorted to the extent that they extend primarily in the axial direction, this degree of distortion is not essential since adequate expansion of the sleeve may be readily obtained with without distortion to such an extent.

It will be appreciated that even though the sleeve is a close fit around the coil, the strands 24 are allowed to distort perpendicular to their lengths by virtue of the fact that the coil diameter reduces as it expands. For this reason, it is not necessary that the sleeve material be of an elastic nature, although it may be if desired. On contraction of the coil enclosed within the sleeve, the strands tend to return to their original condition in which they are generally rectilinear and the slits are substantially closed.

The original contracted length of the sleeve corresponds to the length of the sides 12. For a given diameter of coiled service line, expansion of the sleeve by a factor of 3 or 4 times (or even more) its original contracted length can be realised by appropriate selection of the slit lengths and number of slits in each row. For example, the sleeve may be designed so that it can expand by a factor of 5 or more thus enabling the sleeve to expand and contract freely with the coiled service line it is fitted to when the latter expands and contracts over a typical range of 2 feet to 10 feet.

Because in practice the sleeve will be a close fit to the coiled service line, as the latter expands, the sleeve will expand with it. If desired, the sleeve may be fastened, e. g. at each end, to the coil although this will not usually be necessary if the sleeve material is sufficiently flexible and the sleeve is a reasonably close fit to the coil.

The sleeve material is one which is flexible so that the sleeve can expand and contract freely with the coil in use. The sleeve material may for instance be a plastics material such as nylon or a composite material such as a rubberised or plastic coated fabric. Where a rubberised or plastic coated fabric is used, the sleeve may be fabricated so that its external surface is that side of the sheet which is coated or rubberised.

The material used will desirably have some degree of resilience so that the sleeve will tend to self-contract, i. e. relax back towards its original shape when no longer subject to expansion forces. However, it is not usually necessary for the sleeve to contract fully to its original shape and size since the coils in any event tend to increase in length as a result of sagging even when not undergoing expansion during vehicle manoeuvring. The material chosen will also be sufficiently robust to withstand extended periods of expansion and contraction and also periodic cleaning of the coils by high pressure water spraying.

In the embodiment of Figures 2 and 3, the anti-tangling element is in the form of a sleeve produced from a sheet of material formed with slits. In an alternative implementation of the invention, the sleeve may instead comprise a hose or ducting material of a design such as that used in applications such as exhausting moisture laden air from clothes drying machines such as tumble driers, extraction of fumes and dust.

Such forms of ducting are avaiable for example from suppliers such as Flexible Ducting

Limited of Glasgow, Scotland. To allow for drainage of any water that may collect in the sleeve during use, the hose or ducting material (e. g. a lightweight, durable plastics material or composite material, such as plastics coated textile) may be perforated with one or more holes along its length..

Figure 4 illustrates a pair of coiled service lines 3A and 3B, one of which is provided with an anti-tangling element 4 such as that illustrated in Figures 2 and 3. As will be seen, the convolutions of the two lines 3A, 3B are prevented from tangling with one another since the gaps between adjacent convolutions of the line 3B are bridged by the anti-tangling element. It will be appreciated that, while only one service line is provided with an anti-tangling element, both service lines may be so provided if desired.