GB2349653A

GB2349653A - Pivotable column

Info

Publication number: GB2349653A
Application number: GB9910332A
Authority: GB
Inventors: Alan John Jenvey
Original assignee: Abacus Holdings Ltd
Current assignee: Abacus Holdings Ltd
Priority date: 1999-05-06
Filing date: 1999-05-06
Publication date: 2000-11-08
Anticipated expiration: 2019-05-06
Also published as: GB2349653B; GB9910332D0

Abstract

A column (10) pivotable about a pivot (13) offset to one side of the column and having releasable locking means (30) to lock the column upright, has a ram (14) connected or connectable to raise and lower the column. The cylinder of the ram has mounting means (22) aligned in the plane of the longitudinal axis of the cylinder. The ram is mounted opposite pivot (13) and extends as the column is lowered.

Description

COLUMN UNIT This invention relates to a column unit for mounting an appliance at an elevated location, such as a street lighting column.

European Patent Application No 290 208 describes and claims a column unit comprising a normally upright column attached to a base member by way of a generally horizontal pivot which is offset to one side of the column and releasable locking means operable to lock the column relative to the base member in its upright position, characterised in that a fluid operated device in particular a ram, is connected or connectible between the column and the base member and is operable to raise and lower the column by pivoting it about the pivot.

While the column unit described in the above identified European Patent Application functions well under certain operating conditions, it has not been found to be suitable for use in mounting a heavy appliance, and has also been expensive to manufacture.

In the only embodiment of the column unit described in EP 290 208A, the base member is provided with first mounting means to which a piston of the ram is connected or connectible, and the column is provided with second mounting means to which a cylinder of the ram is connected or connectible, the first and second mounting means being disposed at closely adjacent locations.

It is a particular disadvantage of that column unit that the cylinder of the ram is connected or connectible to the second mounting means by means of mounting means offset from the plane of the longitudinal axis of the cylinder. This gives rises to a bending force which is of course increased when a heavier appliance is mounted on the column.

It is an object of the present invention to provide a column unit in which the above disadvantages are reduced or substantially obviated. The present invention provides a column unit comprising a normally upright column attached to a base member by way of a generally horizontal pivot which is offset to one side of the column, releasable locking means operable to lock the column relative to the base member in its upright position, a ram connected or connectible between the column and the base member and operable to raise and lower the column by pivoting it about the pivot and mounting means provided on the column to which a cylinder of the ram is connected or connectible characterised in that the cylinder of the ram is provided with mounting means in the plane of the longitudinal axis of the cylinder for engagement with the mounting means provided on the column.

Desirably, the ram is disposed on the opposite side of the column to the pivot, and preferably extends as the column is pivotally lowered and contracts as the column is pivotally raised.

Preferably, the base member includes a plate, the column includes a base flange which lies against the plate when the column is in its upright position, and the pivot interconnects the plate and the base flange.

The locking means can comprise one or more securing elements which pass through holes in the plate and/or in the base flange.

Advantageously, the plate is disposed at or close to ground level and the pivot is disposed substantially in the plane of the plate, so that when the column is fully lowered the height of the overall unit in the region of the base member is not substantially greater than the length of the base flange.

Conveniently, the base member is provided with mounting means to which a piston of the ram is connected or connectible.

The second mounting means provided on the column preferably comprises a yoke comprising a pair of brackets, one of each being attached, preferably by welding, to diametrically opposite sides of the column. The yoke is adapted to receive and engage location plates mounted on the column unit and spaced apart to receive the cylinder therebetween.

Desirably, the column unit further comprises a safety interlock which is operable to retain the column in its upright position after the locking means has been released and which is readily released to permit the column to be pivotally lowered. This interlock is preferably provided by a latch device which automatically re-engages as the column returns to its upright position.

This invention will now be further described, by way of example only, with reference to the accompanying drawings, in which-.

Figure lisa general view of a column unit according to the present invention.

Figure 2 is a side elevation of a lower part of the column unit shown in Figure 1 ; Figure 3 is a sectional side view of a lower part of a column which forms part of the unit; Figure 4 is a view in the direction of arrow X in Figure 3; Figure 5 is a sectional side view of an upper part of a base member which also forms part of the column unit; Figure 6 is a view in the direction of arrow Y in Figure 5 ; Figure 7 is a side view of the column unit, illustrating in particular a latch device; and Figures 8 and 9 show the manner of operation of the latch device.

Referring first to Figures 1 and 2, the illustrated column unit comprises a hollow column 10 which normally occupies an upright position (as shown) and which at its upper end mounts an appliance (such as lighting) at an elevated location. For the sake of convenience, the appliance is not actually depicted in the drawings. At its lower end, the. column 10 is attached to a base member 11 which is anchored into the ground, ground level being indicated at 12. Such attachment is by means of a generally horizontal pivot 13 which allows the column 10 to be pivotally lowered in order to bring the appliance down to ground level, inter alia for servicing. As can be seen to advantage in Figure 2, the pivot 13 is offset to one side of the column 10. Raising and lowering of the column is performed by means of a double-acting ram 14 which is disposed on the opposite side of the column 10 to the pivot 13.

Referring now also to Figures 3 and 6, at its lower end the column 10 has a flat base flange 15. When the column is in its upright position, this flange lies against a flat plate 16 on the upper end of the base member 11. The flange 15 is provided with two spaced bushings 17 which receive between them a single bushing 18 on the plate 16, and the pivot is formed by a pivot pin inserted through aligned holes in these bushings. The pivot 13 lies generally in the planes of the flange 15 and of the plate 16.

As will be manifest from Figure 2, the ram 14 is mounted upon the column in inverted configuration. A piston 19 of the ram is connected to the base member 11 by means of a pair of laterally spaced mounting lugs 20 provided on the plate 16. The connection is made by means of a pivot rod (not shown) being passed through aligned apertures in the mounting lugs. The plate 16 is recessed between the lugs 20, to allow for unimpeded operation of the ram 14 during raising and lowering of the column.

A yoke 22 is welded to the column 10 adjacent to the plate 15. The yoke 22 comprises a pair of C-shaped brackets 22', 22"each of which defines an aperture in conjunction with the wall of the column 10. A location plate 42 is mounted on each side of the cylinder 21 of the ram 14. The location plates 42 are in the shape of a right angled triangle, with a keyhole slot 44 formed in the non-right angled corner adjacent to the plate 16. Connection between the cylinder 21 and the column 10 is made by engaging each lower arm of the C-shaped brackets 22', 22"in the respective keyhole slot 44 of the location plate 42. Locking means is provided to lock the column 10 in its upright position during normal useage, and comprises a pair of upstanding threaded posts 24 mounted on the plate 16 at a location remote from the pivot 13. These posts extend through respective apertures 25 in the flange 15, and are engaged by nuts 26 (see Figure 2). The apertures 25 are made of oblong configuration to provide the necessary clearance for the posts 24 as the flange 15 tips during lowering of the column.

Referring in particular to Figure 5, the base member 11 is generally hollow to allow for a mains electric cable to pass therethrough for powering the appliance. Since normal mains cables are not designed to undergo repeated flexing, a terminal block (not shown) can be mounted on an upstanding projection 27 extending above the plate 16, at which the mains cable can be terminated. Another, more flexible cable can then be led from the terminal block up through the interior of the column 10 to the appliance itself. It will therefore be this other cable rather than the mains cable itself which is subjected to flexing as the column is lowered and raised.

Reference numeral 28 designates an opening in the lower part of the column 10 to allow access to the internal electrics for servicing. This opening will normally be closed by a cover (not shown).

In the illustrated embodiment, the ram 14 is not permanently connected to the column unit, but rather is attached only when the column 10 needs to be lowered. In order to effect such lowering, after the ram 14 has been attached the nuts 26 are disengaged from the posts 24 to release the aforesaid locking means, whereupon power can be supplied to extend the ram and thereby push the column 10 over from its upright position. Thereafter, controlled lowering of the column continues under the action of the ram. To raise the column these actions are reversed and the ram 14 contracts to pull the column back up into its upright position.

In order to prevent the column 10 from toppling over if the locking means is inadvertently released without the ram 14 connected, a interlock can be employed which retains the column in its upright position but which is readily released when the ram is connected to permit lowering of the column to commence. One example of such a safety interlock (in the form of a latch device 29) is depicted in Figure 7, which comprises a latch member 30 pivotally mounted on the flange 15. The latch member 30 has a curved slot 31 which normally engages a pin 32 on the plate 16. Before pivotal lowering of the column can commence, the latch member 30 must be rotated about its pivot to the position shown in Figure 8, wherein an abutment surface 33 (normally at the top of the member 30) rests against the pin 32. As the flange 15 moves away from the plate 16 during lowering of the column 10, the latch member 30 is free to pivot under gravity to the position indicated in Figure 9. When the column 10 is subsequently raised back into its upright position, an inclined surface 34 at the bottom of the member 30 engages the pin 32 and causes the member 30 to pivot slightly to one side: when the pin 32 becomes aligned with the slot 31, the latch member 30 can then pivot back again to re-engage the latch device. Thus, the interlock is automatically reengaged each time the column 10 is returned to its upright position.

If desired, a vandal-proof security device can be fitted to the column unit to prevent the column from being lowered by unauthorised persons.

The column unit described above provides an effective way of allowing for the appliance to be lowered e. g. for servicing at relatively modest cost. For column units which are not particularly high, the ram 14 and its associated power source can be a fairly lightweight unit which is easily managed by a single operator, thereby minimising the personnel needed for the lowering/servicing operation. Indeed, for certain applications the power source for the ram can be hand-operated thereby reducing the overall cost even more.

Because the plate 16 is positioned close to ground level and the pivot 13 is positioned generally in the plane of the plate 16, when the column 10 is fully lowered the overall height H of the unit in the region of the base member 11 is little more than the length of the f lange 15, as is illustrated in broken lines in Figure 2. Therefore, the column unit is extremely useful in situations where lighting must be periodically lowered to allow for the passage of wide loads having a relatively small ground clearance. This would otherwise require the lighting columns to be totally uprooted, thereby greatly increasing the cost of the exercise For relatively heavy columns, the inverted mounting of the ram 14 provides an effective way of lowering the column safely, which has previously been a problem with column units incorporating a simple pivot or hinge. This is because the ram 14 extends while the column is lowered, and contracts during raising.

Claims

Claims 1. A column unit for mounting an appliance at an elevated location, comprising a normally upright column attached to a base member by way of a generally horizontal pivot which is offset to one side of the column, and releasable locking means operable to lock the column in its upright position, a ram (14) connected or connectible between the column (10) and the base member (11) is operable to raise and lower the column (10) by pivoting it about the pivot (13), and mounting means (42) provided on the column (10) to which a cylinder (21) of the ram (14) is connected or connectible, characterised in that the cylinder (21) of the ram (14) is provided with mounting means (42) in the plane of the longitudinal axis of the cylinder (21) for engagement with the mounting means (42) provided on the column (10).
2. A column unit according to claim 1, characterised in that the ram (14) is disposed on the opposite side of the column (10) to the pivot (13).
3. A column unit according to claim 1 or claim 2, characterised in that the ram device (14) extends as the column (10) is pivotally lowered and contracts as the column (10) is pivotally raised.
4. A column unit according to any preceding claim, characterised in that the column (10) has a base flange (15) which lies against a plate (16) on the base member (11) when the column (10) is in its upright position and the pivot (13) interconnects the base flange (15) and the plate (16).
5. A column unit according to any of claims 1 to 4 characterised in that the mounting means (42) comprises a pair of location plates (42) welded to the column (10).
6. A column unit according to claim 5 characterised in that each of the location plates (42) is provided with a keyhole slot (44).
7. A column unit according to claim 5 or claim 6 characterised in that the mounting means (22) provided on the cylinder (21) comprises a yoke (22).
8. A column unit according to claim 7 characterised in that the yoke (22) comprises a pair of C-shaped brackets (22', 22").
9. A column unit according to any of claims 4 to 8, characterised in that the locking means comprises one or more securing elements (24) which pass through holes (25) in the plate (16) and/or in the base flange (15).
10. A column unit according to claim any of claims 4 to 9, characterised in that the plate (16) is disposed at or close to ground and the pivot (13) is disposed substantially in the plane of the plate (16).
11. A column unit according to any preceding claim, characterised by the provision of a safety interlock for retaining the column (10) in its upright position after the locking means has been released, the safety interlock being readily releaseable to permit the column (10) to be pivotally lowered, the safety interlock (29) preferably being in the form of a latch device which automatically re-engages as the column returns to its upright position.