Folding column

FIELD OF THE INVENTION

The present invention relates to a folding column.

BACKGROUND ART

Lighting columns are commonly used for mounting a lamp, television camera or the like at an elevated location. These are used for the provision of street lighting and the like, and for surveillance of selected areas. Generally, columns need to provide adequate mechanical support to the equipment held at the top of the column, to retain the cables that must be run to that equipment, and to allow access to those cables and any associated electrical equipment for maintenance and repair purposes.

From time to time it is necessary to service the mounted equipment, for example to replace bulbs where the column is being used to support lamps. This is often done by the use of a vehicle mounted access platform which can be raised on an articulated arm so as to lift personnel to the top of the column. This is not always possible, however, as there are circumstances such as station platforms, pedestrian walkways, sports grounds etc, where a raiseable platform cannot be taken. There are also areas where it would not be safe to raise personnel to the top of the column, such as in proximity to overhead electrical cables. In such circumstances, a foldable column is advantageous since a lower section thereof (below the folding point) can remain fixed in the ground, whereas the upper section (above the folding point) can be folded down to a lowered position approximately parallel to the ground, by which the (normally) upper end thereof is made accessible to personnel standing on the ground.

Previous designs of folding column are shown in GB2224292 and GB2362396. GB2224292 shows a simple design in which there is a break point in the column allowing the upper section to be lifted out of engagement with the lower section and then folded. This does however

require a relatively complex manipulation tool which is able to lift the entire weight of the upper section so as to disengage the two parts and then support the upper section while it is folded down. GB2362396 includes a counter balance and an actuator within the lower section which together control the descent of the upper section. Whilst this addresses the difficulties of GB2224292, it introduces significant additional complexity (and therefore cost) into the column in order to provide a function that will only be exercised very occasionally.

FR2811003 shows an articulated mast for a directional microwave Ink antenna. A hinge is formed in the mast, and attachment points are provided on either side for an actuator which causes the hinge to open thereby lowering the mast.

US 4,903,442 and EP-A-0, 290, 208 each show a lighting column hinged at its base. The hinges can be opened to lower the column, by actuating a hinge located at ground level.

SUMMARY OF THE INVENTION

The present invention therefore provides a folding column comprising a substantially hollow lower section, the interior of which is accessible via a removable hatch, and an upper section attached to the lower section via a hinge located on the lower section above the hatch, the upper section having an attachment point spaced from the hinge and the lower section having an attachment point, both attachment points being adapted to temporarily receive respective parts of an external actuator for urging the attachment points apart and thereby rotating the upper section on the hinge.

By locating the hinge above the hatch, the invention allows an operator to work at comfortable height and lifts the hinge mechanism away from the ground level at which corrosion and other forms of damage are more likely to progress.

Also, for a lighting column it is usual for power cables to arrive in the lower section from a conduit passing nearby or beneath the column;

generally, two mains power cables will need to be fed into the lower section, one being the incoming power feed and the other leading to columns further along the conduit. Within the lower section, these will be connected to a distribution unit from which a cable will be connected via a switched and/or fused connection to form a spur running up the column. The distribution unit will typically be located behind the hatch to allow for installation and maintenance thereof. The spur cable need only carry the power for one light, whereas the mains cables need to carry power for all the lights on that circuit, so the mains cables are much more substantial than the spur cable.

Thus, by locating the hinge above the hatch rather than at the base, operation of the hinge only requires the lighter gauge spur cable to bend rather than both heavier gauge mains cables. This reduces wear and tear on the cables and thus enhances the reliability of the system as a whole, and also reduces the force needed to operate the hinge.

The hinge can include two opposing plates, one attached to the upper section and one attached to the lower section, each having a bore therethrough, the bores being aligned to accept a locking means. One or both of the bores can be threaded to accept a bolt to lock the hinge, for example. Alternatively, a bolt can be passed through the bores and secured with a nut.

The attachment point of the upper section can be on a lever extending therefore, to provide the necessary torque to control the descent and allow the ascent of the upper section. This also allows a further safety lock to be provided, by providing a member forming part of the lower section adjacent to the lever (when the column is raised). The member can then have a retractable catch for engaging with a recess on the lever such as a bore. The catch can be a spherical member such as a ball bearing, preferably spring-loaded into engagement. The lever can lie between two such members, to provide a balanced engagement force.

The attachment point of the lower section can comprise a recess for receiving a part of the actuator, preferably with an associated retractable catch for selectively retaining an actuator.

Such a column can be used for lighting purposes, for supporting cameras, or for other purposes.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will now be described by way of example, with reference to the accompanying figures in which;

Figure 1 shows a vertical section through a first embodiment of a folding column according to the present invention, viewed from one side with the separate actuator fitted;

Figure 2 shows a vertical section through the folding column of figure 1, from the front and with the separate actuator omitted;

Figure 3 shows the safety lock highlighted in area III of figure 2 in more detail;

Figure 4 shows a vertical cross section through a second embodiment;

Figure 5 shows a vertical cross section of the embodiment of figure 4, in a plane transverse to that of figure 4;

Figure 6 shows a second embodiment of a folding column according to the present invention in the upright state; and

Figure 7 shows the embodiment of figure 6 in the open state.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Figures 1 and 2 show a lighting column incorporating a folding mechanism according to the present invention. The lighting column 10 incorporates a lower section 12 connected to an upper section 14 via a hinge 16. Only part of the upper section 14 is shown, for clarity. This will

normally extend upwards by a significant distance in order to carry a light bulb, by a form of lighting, or other equipment such as CCTV cameras.

The lower section 12 comprises a foot section 18 which would generally be buried so as to support the lighting column 10. In the region of the lower section 12 that will be above the ground, a hatch 20 is provided in the generally cylindrical structure for lower section 12. This hatch is secured in place over a corresponding opening 21 in the lower section 12 using a suitable lock and/or latch mechanism as is generally known in the art, and can be removed to allow access to the interior of the lower section 12. In figure 1, the hatch 20 is shown in place but it will obviously be removed to allow access during the processes illustrated in figure 1.

The upper section 14 comprises a generally cylindrical strut 22 of somewhat narrower width than the lower section 12, which extends upwards to support equipment at the top of the column. This is seated in a base 24 connected to the hinge 16. A lever arm 26 extends from the base

24 past the hinge point 16. As can be seen in figure 1, the hinge 16 comprises a pair of upstanding flanges 28, 30 formed on an upper face of a lower section 12, between which extends the lever 26, with a pin 32 passing through the flanges 28, 30 and the lever 26 to define the hinge 16.

The flanges 28, 30 and the pin 32 are set back near to the rear of the lower section 12, the front being defined by the hatch 20. This allows space within the lower section 12 for the lever arm 26 to extend forward of and below the hinge 16 thereby to obtain some leverage as will be described later.

The base portion 24 also comprises a flat lower plate 34 which, when the upper section 14 is completely upright, abuts against a top plate 36 on the lower section 12. This allows for the weight of the upper section 14 to be transferred to the lower section 12 across the entire face of the plates 34, 36 avoiding wear on the hinge 16. It also allows for a bolt 38 to pass through bores 40 on the plates 34, 36 in order to provide a first line lock against unintended folding of a column. The bolt 38 can pass through a

bore and be secured with a suitable nut within the lower section 12, or one or other of the bores 40 within the plates 34, 36 can be threaded to retain the bolt 38.

A cover 42 is provided for the join, and sits around the cylindrical strut 22 of the upper section. It is generally frusto-conical in shape so as to conform at it's upper edge to the width of the cylindrical strut 22 and at its lower edge to the width of the lower section 12. It can be put into place to cover the hinge 16 and bolt arrangement 38, and lifted to reveal the bolt

38 for removal. Figure 2 shows the lighting column 10 with the cover 42 removed.

To fold the column, a separate actuator 44 is provided. This connects to an engagement point on the lever 26 and on the lower section 12. The former comprises a hole 46 which connects via a suitable pin to an end of the actuator 44. The engagement section on the lower section 12 comprises a suitably reinforced rectangular-section socket 48 which accepts a correspondingly shaped rectangular-section strut 50 on the other end of the actuator 44. The strut 50, when in place, extends outwards of the column 10 to provide a pivot point 52 at its tip. The strut 50 is retained in place within the socket 48 by a pin 54 within the lower section 12 which is held in a guide 56 so that, once the rectangular section strut 50 has been inserted, the pin 54 can be dropped under its own weight into a corresponding recess 58 in the rectangular-section strut 50. This then retains the strut 50 in place. The strut 50 can be disengaged by lifting the pin 54 by a suitable handle 60, which may be weighted so as to bias the pin 54 downwards into engagement.

The remainder of the actuator 44 consists of a linear actuator element 62 which is activated by a rotary drive 64 at its lower point. The linear actuator element 62 extends when the drive 64 is rotated by an external means. Such external means can comprise a crank handle or, more preferably, a suitable battery-operated power tool such as a drill. Such drills are commonly available in a portable form and can provide sufficient torque to operate the linear actuator element 62. When so operated, the linear actuator element 62 extends in length. Prior to

actuation, the tip 64 of the linear actuator element 62 is connected to the lever 26 at the engagement point 46 by a suitable pin which projects through and engages with engagement point 46. Thus, operating a linear actuator 62 forces the end of the lever 26 upwards.

The length of the rectangular-section 50 and the relative shapes of the lever 26 and location of the hinges 16 are chosen so that the linear actuator 62 is aligned with its axis as shown at 66, along a line lying forward of the hinge 16. Thus, a torque is extended by the linear actuator 44 on the upper section.

To provide a further safety lock, a pair of flanges 70, 72 extend downwards from the upper face 36 of the lower section 12 either side of the lever 26, sandwiching it between them. At a point along the lever 26, there is a circular-section bore 74, aligned with somewhat larger circular-section bores 76, 78 in the flanges 70, 72 either side of the lever 26. The longer circular-section bores 76, 78 and flanges 70, 72 each accept a spring loaded locking device 80, 82 which is externally threaded and engages in corresponding threading in the bores 76, 78. Locking nuts 84, 86 are provided on the remainder of the spring loaded locking mechanism 80, 82 to secure it in place relative to the bores 76, 78. This is shown in greater detail in figure 3.

Within the spring loaded locking devices 80, 82, there is a ballbearing 88 which is urged towards the lever 26 via a spring 90. When the upper section 14 is fully upright, the bores 74, 76 and 78 are all aligned and the two ballbearings 88 are urged into position by the springs 90 so that they project partly into the aperture 74 of the lever 26. In order to fold the upper section 14 of the column 10, a resistance must be overcome by forcing the ballbearings 88 against the spring 90 and back into the spring loaded locking mechanisms 80, 82. The flanges 70, 72 are made of a sufficient length so as to space the locking mechanisms from the hinge 16 and mean that the torque required to do so is generally more than can be applied by a person at standing height to the column section 22. However, the linear actuator 62 of the actuator 44, under the influence of an external power tool is generally able to provide a higher level of torque that

overcomes the locking device. As the device is automatic in nature, no specific use intervention is needed and the lock is released automatically once a suitable actuator 44 is fitted to the column 10 and operated.

Figures 4 and 5 show a further embodiment. This differs from the above-described embodiment only in respect of the means by which the actuator 44 is attached to the column, and therefore only this area of the column (etc) is illustrated.

Instead of the socket 48 and the strut 50, a bracket 100 hooks over the lower edge of the opening 21 for the hatch 20. This bracket consists of a strut 102 extending transversely from the column 10 and ending with a pivot point 104 in the form of a through-hole to which the linear actuator 44 can attach. This is held in position by a hook 106 made from two plates, one attached on either side of the strut 102, each of which extends upwardly and has a vertical slot 108 to receive the lower edge of the opening 21. This holds the bracket 100 in place and positions the pivot point 104 correctly. Thus, this embodiment of the present invention provides a secure folding column which is only capable of being folded by suitable personnel provided with the necessary actuator 44. A first line lock is provided in the form of the bolt 38, which will prevent accidental or unintended folding of the column 10. A second line lock is provided by the mechanism 68 which will further prevent unauthorised folding even by those willing to lift the cover 42 and remove the bolt 38. When operated by suitable authorised personnel, the upper section 14 of the column 10 can be folded in a steady and controlled manner so as to provide the necessary action. However, the core elements of a column 10 are simple and economic to provide in large numbers.

Figures 6 and 7 show a second embodiment of the present invention, figure 6 being in the closed or upright state and figure 7 being in the open or folded state. Referring to figure 6, a lower section 212 has an opening 221 for a hatch 220 through which an interior space of the lower section 212 can be accessed. At the top of the lower section 212, a pair of hollow box sections 214, 216 are welded in a horizontal disposition. On top of the

box sections, a flat horizontal plate 218 is welded, located toward the front of the lower section 212. Toward the rear of the lower section 212, a flange 222 extends upwardly from the lower section between the two box sections 214, 216, to which is hinged an annular ring 224 via a hinge pin 226 which passes through both a tab 228 extending from the ring 224 and the flange 222 and is secured in place via a split pin 230. A further flat horizontal plate 232 is welded to the underside of the ring 224; this and the flat horizontal plate 218 are sized so that in the closed position, they abut and allow the weight of the upper section to be supported.

A pair of aligned through-holes are formed in each horizontal plate 218, 232 to allow locking bolts to be fitted, retaining the hinge in the closed state and the upper section in the upright state. These holes can be smooth, in which case the bolts will require a suitable nut such as a locking nut. Alternatively, the holes in one plate can be internally threaded; generally it will be preferable to thread the hole in the plate 218 to allow the bolt to the inserted from above.

The upper section, generally depicted at 234, consists of an elongate column section as before, and is welded to the ring 224. The column section can carry lights or other equipment, as before. A power cable for the lights can be fed between the box sections 214, 216 and then through the ring 224. Some slack cable will need to be provided to allow for the hinging action. Figure 6 shows an end portion of the actuator 236 in place, ready to fold the column. As before, this can be a simple actuator powered by (for example) a cordless electric drill. It consists of a piston 238 which can be extended from a housing 240 under the control of an operator. A pair of struts 242, 244 are rotateably attached to the housing 240 proximate the end portion; these are shaped to fit within the box sections 214, 216 and are sufficiently long to project out of the box sections 214, 216 on the other side of the lower section 212. Here, they are secured by a pin 246 and a spring clip 248. Hence, the housing is securely attached to the lower section 212.

The tip 250 of the piston 238 has a hole to allow it to be attached to a tab extending from the ring 224, which therefore acts as a short lever for the upper section 234. The two are connected via a pin 254 which is held in place by a spring clip 256. Thus, once fitted, the piston 238 can be extended out of the housing 236, and this will open the hinge as shown in figure 7, lowering the upper section 234.

A frusto-conical cone (not shown) can be provided around the upper section 234 in order to conceal the hinge arrangement, as shown in figure 1. This can be slid up the elongate column section to allow access. Preferably, a lock is provided against such unauthorised movement; this can be in the form of a bolt passing from within the interior of the lower section 212 through the top thereof and into a suitably threaded section within the cone.

It will of course be understood that many variations may be made to the above-described embodiment without departing from the scope of the present invention.