Title: Raising and Lowering of Columns
The present invention relates to an improved arrangement for the raising and lowering of masts, in particular 1 ighting masts, which require to be raised and lowered for repair and routine maintenance
The present invention furtherrelates to an improved method for the raising and lowering of amast,
in particular a lighting mast.
In the development of lighting systems, (for example those used in the lighting of locations such as road systems, car parks and sports stadia), there has been acontinuous requirement forincreased height and size of lighting installations, leading to lighting masts having a greater cross-section and increased weight.
Currently available systems forraisingand lowering masts of this type, for ex ample the systems described in GB Patent No 2 349 653 are manually operated and controlled, rather than automatic, and are suitable for use with the previously used smaller systems, but are not ideally sui ted for the raising and lowering of the larger systems, because of the need for manual intervention by an operator working in close proximity to the base of the mast.
It is an object of the present invention to provide an arrangement for the raising and lowering of a mast, in particular a lighting mast, in which the above disadvantages are reduced or substantially obviated.
It is a further obj ect of the presenti nvention to provide a method for the raising and lowering of a mast, in particular a lighting mast, in which the above disadvantages are reduced or substantially obviated.
The present invention provides an arrangement for the raising and lowering of amast, which comprises an upper mast portion and a base which upper mast portion is rotatable about a
horizontal- pivot axis located in the base of the mast, which arrangement comprises
(i) docking means selectively engageable for restraining the upper mast portion against rotation,
(ii) attachment means for attaching drive means for driving the docking means between a first engaged configuration wherein the upper mast portion is restrained against
rotation and a second disengaged configuration wherein the upper mast portion is free to rotate, and
(Hi) locking means, selectable via an intermediate unlocked configuration between a first locked configuration in which the docking means is engaged and a second locked configuration in which the docking means is disengaged,
characterised in that the locking means is controllable remotely to allow automatic operation of the raising and lowering sequence.
A preferred embodiment of the arrangement according to the invention further comprises sensors for sensing the vertical alignment of the uppermast portion and/or the configuration of the locking means and/or the configuration of thedocking means and/ortlie proximity ofthe upper mast portion to the ground (in the lowered position).
A further preferred embodiment ofthe arrangement according to the invention comprises drive means for driving the docking means preferably in the form of hydraulic rams, wh ich attach to the attachment means. The drive means for driving the docking means are preferably adapted also to drive the locking means.
In a particul arly preferred embodiment ofthe arrangement according to the invention, the locking means is located in the baseof the mast and provides the horizontal axis about which the upper
mast portion is rotatable.
A particularly preferred form of locking means is described and claimed in the applicant's co-pending GB Patent Application No. 0426208.5.
The arrangement according to the invention is preferably provided with a manual override to allow controlled raising and lowering of the mast in the event of a failure of the automatic system.
The present i nvention further provides a method for the raising and lowering of a mast comprising an upper mast portion and abase which upper mastportion is rotatable about a horizontal pivot axis located in the base ofthe mast, in which an arrangement comprising
(i) docking means selectively engageable for restraining the upper mast portion against rotation,
(ii) attachment means for attaching drive means for driving the docking means between a first engaged configuration wherein the upper mast portion is restrained against
rotation and a second disengaged configuration wherein the upper mast portion is free to rotate, and
(iii) locking means, selectable via an intermediate unlocked configuration between a first locked configuration in which the docking means is engaged and a second locked configuration in which the docking means is disengaged,
is operated remotely according to a sequence of steps comprising
(a) confirming that the upper mast portion is raised in the vertical position that the docking means is in the first engaged configuration and that the locking means is in the first locked configuration;
(b) releasing the locking means into the intermediate configuration and confirming that it is
released; .
(c) driving the docking means into the second disengaged configuration and confirming that it
is disengaged;
(d) engaging the locking means in the second locked configuration and confirming that it is
locked;
(e) lowering the upper mast portion;
(f) raising the upper mast portion into the vertical position and confirming that it is raised;
(g) releasing the locking means into the intermediate configuration and confirming that it is
released;
(li) driving the docking means into the first engaged configuration and confirming that it is engaged; and
(i) engaging the locking means in the first locked configuration and confirming that it is locked.
An arrangement according to the invention for the raising and lowering of a mast, and a method for its operation will now be described with reference to the accompanying drawings, in which:
Figure l is a perspective view of a mast (upper mast portion truncated) in the raised, docked and
locked position, with hydraulic lift rams attached;
Figure 2a is a view of the attachment face of a mast of Figure 1 in the raised, docked and locked position, with hydraulic lift rams attached;
Figure 2b is a section on the line B-B of Figure 2a;
Figure 2c is an enlarged view of the region C of Figure 2b;
Figure 2d is a side view of the mast of Figure 2a;
Figure 2e is a section on the line A-A of Figure 2d;
Figures 3a to 3e are views corresponding to Figures 2a to 2e in the raised, docked and unlocked position;
Figures 4a to 4e are vi ews corresponding to Figures 2a to 2e in the raised, undocked and unlocked position;
Figures 5a to 5c are views corresponding to Figures 2a to 2e in the raised, undocked and locked position; and
Figures 6a to 6e are views corresponding to Figures 2a to 2e in the lowered, undocked and unlocked position.
As can be seen from Figure 1, a mast shown general ly at 10 comprises an upper mast portion 2 and a base portion 4. The upper mast portion 2 is in tine form of a hollow tapering cylinder and is shown truncated in the drawings.
The base portion 4 comprises an upper base portion 6 and a lower base portion 8. The upper base portion 6 is in the form of a substantially hollow square section box. The upper mastportion 2 extends into the upper base portion 6 and is secured thereto. The lower base portion 8 is secured to the ground (not shown). A docking latch 12 is formed at the lower end of the upper base portion 6, for engagement with a co-operating notch 14 in the upper end of the lower base
portion 8. A horizontal pivot axis 16 extends through the upper base portion 6 and terminates at each end in a cam ram 18, each of which cam rams 18 comprises a cylinder 20, a shaft 22 which extends through the cylinder 20 and is slideable therein and a cam plate 24 mounted on a first end of the shaft 22. The second end of the shaft 22 projects through an aperture in the free end of the cylinder 20. One external end face only of one cam plate 24 is visible in Figure 1,
A chock plate 26, having an aperture28 in the form of a figure of eight, is provided on a side wall 30 of the upper base portion 6. A similar chock plate 26 is located on the opposite side wall of the upper base portion 6 in alignment with the first chock plate 26.
Each circular portion of the figure of eight aperture 28 has an internal diameter corresponding to the diameter of the cam plate 24.
in the position shown inFigure 1, the cam plate 24 of the cam ram 18 engages in the upper circular portion of the figure of eight aperture 28.
The neck portion of the aperture 28 is sized so as to allow the shaft 22 of the cam ram 18 to pass freely between the circular portions of the cam ram 18.
Upper U-shaped mounting brackets 32 and lower mounting brackets 34 are located on the upper base portion 6 and lower base portion 8 respectively, for receiving lift ram cylinders 36. The left rain cylinders 36 are supplied in a manner known per se by a manifold 3 8 mounted on abracket 40 secured to the cylinders 36 by means of yokes 42.
In Figure 1, the hydraulicram cylinders 36 are shown in a partially extended configuration with the mast in a raised, docked and locked position.
Figure 2a is a view of the mast ofFigure 1 in the same configuration, but showing the attachment face 44 of the upper base portion 6.
A second manifold 46, for supply to the cam ram 18 is provided.
As can be seen .from Figures 2c and 2e, the mast is provided with a plurality of sensors S1 to S8, which have the following functions:
' i Sensors S1 and S2 together sense the start of the extension of the lift rams 36 and full closure of
these rams:
Sensors SI and S3 together sense the vertical alignment of the mast 10;
Sensors S1 and S4 together sense the full extension of the lift rams 36 and the start of closure of these rams;
Sensors S5, S6 and S7 together sense the extension and closure of the cam rams 18;
Sensors SI, S2 and S4 together sense the engagement/disengagement of the docking latch 1.2 relative to the notch 14 and
Sensor S8 senses the proximity to the ground of the lowered mast.
As can be seen from Figures 2e and 3e, a pair of cam rams 18 are located aligned on the hori7,ontal pivot axis of the mast 10.
Each of the cam rams 18 is moveable between a first, locking position as shown in figure 2d and 2e, in which the cam plate 24 of the cam ram 18 is engaged in the upper cylindrical portion of the aperture 28 in the chock plate 26, and an intermediate position, which can be seem most clearly i n figure 3e, in which the cam plate 24 of the cam ram 18 projects from the side wall 30 of upper base portion 6 and the shaft 22 of the cam ram 18 extends through the aperture 28.
The operation of the system will now be described with reference to Figures 2 to 6 of tl
accompanying drawings.
The normal operational position of the mast 10 is shown in Figures 6a to 6e. In this position, the mast 10 is raised, locked by means of the cam plate 24 in engagement with the upper circular portion of the aperture 28 in the chock plate 26. The vertical alignment of the mast 10 is checked by sensor S2 and the extension of the lift rams 36 is sensed by sensors S1 ,S2 and S4. The control system then extends the cam rams 18 until full extension is confirmed by the sensors S6,S7.
The position of the mast 10 is now as shown in Figures 7a to 7e, i .e., raised, docked and unlocked. The control system then extends the lift rams 36 so as to lift the upper mast portion 2 and the upper base portion 6 relative to the lower base portion 8 and to disengage the docking latch 12 from the notch 14. The sensors SI and S4 confirm that the disengagement is complete.
The position of the mast 10 is now as shown in Figures 8a to 8e, i.e., raised, undocked and
unlocked. The control system then retracts the cam rams 18 and hence the cam plates 24 into
engagement with the lower circular portion of the aperture 28 and the sensors S5 and S6 confirm
that the retraction is complete. .
The position of the mast 10 is now as shown in Figures 5a to 5e, i .e., raised, undocked and locked. The control system men retracts the lift rams 36, and the mast is lowered about the horizontal pivot axis 16 until the ground proximity sensor S8 senses a predetermined proximity to the ground, and retraction of the lift rams 36 is terminated.
The mast 60 is now in the position shown in Figures 6a to 6e, i.e., lowered, undocked and locked.
After the required repair or maintenance work has been carried out, the lowering sequence is repeated in reverse, so as to return the mast 10 to the position shown in Figures 2a to 2e.

Claims
I. An arrangement for the raising and lowering of a mast, which comprises an upper mast portion and a base, which upper mast portion is rotatable about a horizontal pivot axis, located in the base of the mast, which arrangement comprises
(I) docking means for restraining the upper mast portion against rotation;
(ii) attachment means for attaching drive means for driving the docking means between a first engaged configuration wherein the upper mast portion is restrained against rotation and a second disengaged configuration wherein the upper mast portion is free to rotate and
(iii) locking means selectable via an intermediate unlocked configuration between a first locked configuration wherein the docking means is engaged and a second unlocked configuration wherein the docking means is disengaged
characterized in that one or more sensors for sensing the vertical alignment of the upper mast portion and/or the configuration of the locking means and/or the configuration of the docking means and/or the proximity of the upper mast portion to the ground is also provided; and the means is controllable remotely to allow automatic operation of the raising and lowering sequence.
2. An arrangement according to claim 1 which further comprises drive means for driving the docking means, attached to the attachment means.
3. An arrangement according to claim 2 in which the drive means comprises hydraulic rams.
4. An arrangement according to any of claims 1 to 3 in which the locking means is provided with drive means.
5. A arrangement according to claims 4 in which the drive means comprises hydraulic rams.

6. An arrangement according to any of claims 1 to 5 in which the locking means is located in the base of the mast and provides the horizontal pivot axis about which the upper mast portion is rotatable.
7. An method for the raising and lowering of a mast which comprises an upper mast portion and a base, which upper mast portion is rotatable about a horizontal pivot axis, located in the base of the mast, in which an arrangement comprising
(i) docking means for restraining the upper mast portion against rotation;
(ii) attachment means for attaching drive means for driving the docking means between a first engaged configuration wherein the upper mast portion is restrained against rotation and a second disengaged configuration wherein the upper mast portion is free to rotate:
(iii) locking means selectable via an intermediate unlocked configuration between a first locked configuration wherein the docking means is engaged and a second locked configuration wherein the docking means is disengaged and
(iv) one or more sensors for sending the vertical alignment of the upper mast portion and/or configuration of the locking means and/or the configuration of the docking means/and or the proximity of the upper mast portion to the ground is operated according to a series of steps comprising
(a) confirming that the upper mast portion is raised in the vertical position, that the docking means is in the first engaged configuration and that the locking means is in the first locked configuration;
(b) releasing the locking means into the intermediate unlocked configuration and confirming that it is released;
(c) driving the docking means into the second disengaged configuration and confirming that it is disengaged;
(d) engaging the locking means in the second locked configuration and confirming that it is locked;
(e) lowering the upper mast portion;

(f) raising the upper mast portion;
(g) releasing the locking means into the intermediate unlocked configuration and confirming that it is released;
(h) driving the docking means into the first engaged configuration and confirming that it is engaged and
(i) engaging the locking means in the first locked configuration and confirming that it is locked.