GB2343794A - A device to prevent chafing of cables - Google Patents

Abstract

A device to prevent chafing of, e.g. cables extending through a junction between an upright tubular column (10) and an outreach tubular arm (11) connected thereto. The device comprises a plastics insert (20) introduced along the outreach arm (11) to overhang the inner end thereof and provide a soft edge (24) over which the cable (23) may pass. This prevents the cable from bearing against any sharp metal surfaces which may otherwise cause chafing both during introduction of the cable and in use. The insert (20) preferably includes keyways (27) whereby it may be introduced in the correct orientation with an aperture (22) facing downwardly.

Description

A DEVICE TO PREVENT CHAFING OF CABLES THIS INVENTION, particularly, though not exclusively, is concerned with lighting columns and the like carrying internal electrical means such as cables.

One typical form of column comprises an upright tube from the top of which extends a slightly smaller diameter upright spigot over which there fits closely a tubular collar. The collar carries an outreach arm extending more or less normal to the vertical axis of the column and having, at its outer end, a lamp. The collar which fits over the spigot is usually pierced, at a height above the spigot, to receive the inner end of the outreach arm, and the top of the collar is closed by a welded metal or plastics weather cap.

Cable means supplying the lamp must therefore extend through the junction of the two angularly connected tubular members and it is at this point that the cable tends to become chafed, being usually introduced through the outreach arm and pulled downwardly through the column for connection to the supply. The chafing occurs when the cable insulation rubs against sharp edges of zinc or so-called "dross"which can build up on edges during the process of galvanizing the column and arm after assembly. Chafing can also occur during the service life of the column due to its movements in windy weather with consequent flapping of the cable and chafing at the same column/arm junction.

To avoid this difficulty, there is provided, according to the present invention, a device to prevent chafing of pipes or cables extending through a junction of two angularly connected tubular members, comprising an insert adapted to be located at the junction and to provide thereat a fairlead over which a pipe or cable may pass without local contact with an inner wall of one or both of the tubular members.

The insert may be tubular thus to be insertable by passage along one of the tubular members to a position at the junction thereof there being an aperture in the tubular insert for passage of the cable or pipe.

The insert may include means to receive an insertion tool.

Said insertion tool receiving means may have keyways or the like to ensure correct orientation of insertion.

The insert may include a formation providing an interference fit within one of the tubular members adapted easily to pass over any protuberances on the inner wall of the tubular member.

The insert may be formed from a plastics material.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a side view of an outreach arm mounted on the upper region of a typical lighting column having an outreach arm extending therefrom; Figs. la and lb show two other examples of possible end terminations of the arm inside the column; Fig. 2 is a plan view of the assembly illustrated in Fig.

1; Figs. 3 and 3a are vertical cross-sections illustrating two examples of the device made in accordance with the invention; Fig. 4 is a section taken on line IV-IV of Fig. 3. and Figs. 4a and 4b are side and end elevations respectively of the insert illustrated in Fig. 3a.

Referring now to the drawings, there is shown the upper region of a galvanized steel lighting column 10 with a tubular collar 32 mounted on an upright column spigot 33 and from which there extends an outreach arm 11 to the free end of which is attachable a lamp (not shown). The arm 11 pierces the wall of the collar 32 at 12 and typically has a mitred cut end 13 thus providing a passage of communication between the interior of the column 10 and that of the outreach arm 11.

In the examples shown in Figs. 1 and la the arm 11 extends to a position 14 where it contacts the opposite inner wall surface of the collar 32. In the example shown in Fig. lb, the arm 11 does not extend to a position 14 but is cut short and is welded to a supporting web 36 above it.

The mitred face 13 of the arm 11 in Fig. 1 is provided by sawing, and the collar 32 and arm 11 are welded together at 12. A reinforcing fillet 15 provides additional support and strength for the arm 11.

The top 16 of the bracket may be closed by a welded plate or, after manufacture, by a weatherproof cap usually of plastics.

After assembly the collar and outreach arm are galvanized and during this process a certain amount of zinc and/or socalled'dross'can build up on the end face 13 of the arm 11 and on the internal walls of both tubular parts.

On site, during f itment of the lamp to the outer end of the outreach arm 11 an electrical supply cable is passed along the arm through the mitred aperture at 13 and down the column 10 to be connected to the supply. After initially feeding the cable through the junction, it is necessary for it to be pulled through the assembly to its required length. In this process there is a tendency for the cable insulation to be stripped where it is chafed at the junction between the two tubular parts.

Thus, in accordance with the invention, there is provided a device in the form of a plastics insert 20 (Fig. 3) which is inserted through the arm 11 such that it overhangs the vertical space within the collar 32 and the column 10. The insert in this example has a formed end 21 which abuts the opposite inner wall surface of the collar 32 when correctly located and has an opening 22 through which the cable illustrated at 23 may pass. The inner extremity of the opening 22 is shown at 24 and provides a soft edge over which the cable may easily pass without damage.

The outer cylindrical wall 25 of the insert 20 includes a feathered or ribbed formation 26 to provide an interference fit for the insert in the arm 11 and which will pass over any small protuberances or obstructions on the inner wall surface thereof.

One or more keyways 27 are provided to receive an insertion tool (not shown) which may be used to guide the insert along the arm 11 and to ensure correct orientation such that the aperture 22 faces downwardly.

By this simple means there is ensured the avoidance of any damage to the cable as it is pulled through the arm 11 and down into column 10.

As shown in Figs. 1 and 2, there is typically provided, in the collar 32 a crossbar 30 which locates in diametrically opposed slots 31 in the upper end of the spigot 33 mounted on the column 10. This bar prevents rotation of the collar 32 on the spigot 33 and thus ensures that the outreach arm 11 remains in the correct directional position even if fixing screws 35 fail to provide the necessary locking force. This anti-rotation crossbar 30 can also present a rough surface (due to galvanization) with which the cable may come into contact.

To avoid this difficulty, the bar 30 may be discontinuous and provided in the form of a pair of opposed studs 34 as illustrated in Fig. 2. The provision of these studs as opposed to a continuous bar is incidental to the present invention but is complementary to the provision of insert 20.

As will be seen from Figs. la, lb and 3, with the inclusion of an insert 20 in accordance with the invention, the inner end region of the arm 11 may be simply cut away as illustrated at 28 rather than have a mitred cut as shown at 13.

It is not intended to limit the invention to the above details. For example, the insert may be a simple length of tubular plastics inserted such as to overhang the opening in the tube 11 but the formation of the insert as illustrated in Figs. 3 and 3a is preferable since it provides a stop against the wall of the column 10 and also a flared end 29 to avoid the difficulty of the cable end snagging the insert as it is introduced along the arm. The insert may be made from a somewhat resilient plastics such as polyethylene or polypropylene.

Claims (9)

1. CLAIMS 1. A device to prevent chafing of pipes or cables extending through a junction of two angularly connected tubular members, comprising an insert adapted to be located at the junction and to provide thereat a fairlead over which a pipe or cable may pass without local contact with an inner wall of one or both of the tubular members.
2. 2. A device according to Claim 1, wherein the insert is tubular to be insertable by passage along one of the tubular members to a position at the junction thereof, there being an aperture in the tubular insert for passage of a cable or pipe.
3. 3. A device according to Claim 1 or Claim 2, wherein the insert includes means to receive an insertion tool.
4. 4. A device according to Claim 3, wherein the insertion tool receiving means includes a keyway or the like to ensure correct orientation of insertion.
5. 5. A device according to Claim 3 or Claim 4, wherein the insert includes a formation providing an interference fit within one of the tubular members and adapted easily to pass over any protuberances on the inner wall of the tubular member.
6. 6. A device according to any preceding claim, wherein the insert is formed from a plastics material.
7. 7. A device according to Claim 5, wherein the formation is ribbed.
8. 8. A device according to Claim 1, wherein the insert is a length of tubular plastics material inserted in one of the tubular members such as to overhang the inner end opening thereof.
9. 9. A device according to Claim 1, wherein the insert includes an outer flared end to prevent a cable or pipe from snagging the insert as it is introduced along the tubular member.