GB2239463A - Hinged mast - Google Patents

Abstract

A folding mast of the kind in which the upper section 12 has to be raised relative to lower section 10 prior to tilting about a pivot 13 includes a gravity actuated latch 15 which, on raising the upper section, moves to support the pivot in the raised position. The pivot 13 may be contained in a cylindrical bearing 23 having end plates 24 slidable in the lower section 10. The mast can be used for street lights, flags, aerials and signs. <IMAGE>

Description

HINGED NBS THIS INVENTION relates to masts and the like, and, in particular, to improvements in the means by which masts may be raised and lowered.

Prior Australian Patent No. 494746 describes one such folding mast. Other similar masts are seen in prior Australian Patent Application No. 23889/84 and in PCT/AU83/00171. Folding masts are hinged at some point and a mechanism is provided whereby the mast is locked at the vertical, can be unlocked, and lowered to ground level, being angled down about its hinge. Various proposals exist whereby this is achieved as seen in the above references but no totally satisfactory means of operating a mast exists.

It is an object of the present invention to provide a mast whereby the mast may be lowered about its hinge utilising an operation which is simpler to perform.

Other objects, and various advantages of the invention will hereinafter become more apparent.

The invention achieves its object in provision of a folding mast able to be lowered comprising: a bottom support section; an upper section; a pivot means interconnecting the bottom and upper sections; and a latch means operative to permit angular movement of the upper section about the pivot; the upper and lower sections being locked in a first position against relative angular movement; the upper section being movable vertically from the first position to a second position whereat relative angular movement is permitted; the upper section being retained in the second position by the latch means when the upper section may be lowered; and the latch means comprising an overbalanced member arranged to fall under gravity to a locking position when the upper section is in its unlocked state.

The bottom support section may extend vertically as a post to provide a pivot at relatively low level at which folding may take place with an upper clevis at a readily accessible height to enable folding with little difficulty. The bottom support section may be firmly anchored to ground either being bolted thereto or otherwise fixed by any suitable means.

The upper section may be elongate as a mast or pole extended generally vertically in the locked position to support fixtures at an elevated position.

The upper section may serve as a light pole, flag pole, sign support, support for aerials, etc..

The above set out folding mast may pivot about a simple pin as described below or it may be provided in a bearing which bearing can be arranged to move with the upper section but remain constrained against rotative movement. This way the load on the pivot pin, the weight of the upper section, is better distributed.

This way greater load capacities are achieved and excessive wear on the pivot shaft is reduced.

The invention will now be described with reference to a preferred embodiment as shown in the accompanying drawings in which: FIG. 1 is a side elevation of an embodiment of the invention; FIG. 2 is a front elevation of the embodiment of FIG. 1; FIG. 3 is a side elevation of the embodiment of FIG. 1 that shows the disposition of elements at a partially lowered point in operation of the invention; FIG. 4 illustrates the relative positions of latches and pivots when the embodiment of FIGS. 1 to 3 is locked at the vertical; and FIG. 5 illustrates the relative positions of latches and pivots when the embodiment of FIGS. 1 to 3 is rotated; FIGS. 7 to 9 illustrate features of the folding mast of FIG. 6.

In FIGS. 1 to 3, a mast 22 is mounted above a bottom support section or lower section 11 which serves as a base support of the mast and which can be flanged, etc, with provision for being bolted down in place to hold the upper section or mast 22 erect. The mast 22 is connected to the lower section 11 with an intermediate rotating section 12 which is joined to lower section 11 by a pivot means or shaft 13 by which mast 22 may be lowered. The rotating section 12 drops down over the top of the lower section to telescope the two to a degree and lock the two in the vertical position. So as to be able to fold the mast down a jacking screw 18 may be provided, acting between an upper clevis point 19 on the rotating section 12 and a lower clevis point 20 on the lower section 11.Operation of the jacking screw 18 is to raise the rotating section 12 above the lower section 11 to a point whereat the rotating section 12 is clear of the lower section 11 and is able to rotate angularly thereabout on pivot shaft 13. The raising of rotating section 12 is permitted at the pivot shaft 13 by providing slot 14 in the lower section for passage of pivot shaft 13 which can then rise in the slot 14 as jacking screw 18 operates to raise rotating section 12.

As rotating section 12 is raised, the pivot shaft 13 eventually clears a latch 15 which may then fall onto latch stop 17 whereat pivot shaft 13 may not drop back to the bottom of slot 14 and the rotating section 12 is held above the lower section 11 at a point where it is free to rotate about the pivot shaft. The mast 22 may then be lowered. To reverse the process, the jacking screw needs be operated, the latch withdrawn and the rotating section lowered to its locked position.

In the locked position, a safety locking screw 21 may be utilised to lock the upper and lower sections together.

In operation of the latch 15, a latch bolt 16 may be provided, which bolt may be undone to release the latch to allow its fall onto latch stop 17 when clear by raising pivot shaft 13. In reverse, action of latch bolt 16 may be to catch latch 15 and pull it back off latch stop 17 to clear pivot shaft 13 for movement back to the bottom of slot 14 and the locked position of mast 12.

In FIG. 3, mast 22 is shown partly lowered.

Its weight can be taken on jacking screw 18 as it is lowered by action of the jacking screw. FIGS. 4 and 5 show schematically the relative dispositions of latch 15 in relation to pivot shaft 13 in slot 14 in the vertical mode of FIG. 4 and the free for rotation disposition of FIG. 5.

In the above, the latch stop 17 may assist in carrying loads when turning the rotating section. The jacking screw might be replaced by a hydraulic cylinder or the like. The jacking screw or hydraulic cylinder can be the means by which the mast is returned to the vertical with the screw or ram being expanded to do the raising. when the safety locking screws are in place, the screw or ram can be removed.

In the above, the latching mechanism used in the raising and lowering operations can be enclosed within the base section, which secures it frdm being tampered with, and avoids ingress of foreign matter into the working parts.

In practice of the invention, the mast 22 is locked in the vertical position and held by safety locking screws. If the mast is to be lowered, a jacking screw, ram, etc, is fitted between clevis points on respective upper and lower sections. The locking screws are undone and the latch bolt unscrewed to release the latch. The jack is operated to lift the mast when the latch falls beneath the pivot to hold the mast aloft in its unlocked position when the jack may be used in lowering the mast down angularly about the pivot. When desired, the mast may be raised by reversal of the above procedures. The falling of the latch when cleared by the pivot enables a simpler more efficient means of lowering a mast.

The folding mast of FIGS. 6 to 9 illustrates an improved form of the invention with a modification to the pivot. In these drawings the pivot shaft 13 operates in a pivot shaft bearing 23 which is guided in slots 14 in the base section 11. The purpose of the pivot shaft bearing 23 is to provide an efficient bearing for the shaft 13 and the ends of the bearing are guided by end plates 24 in the slots 14 preventing the bearing from rotating, thus ensuring that the shaft 13 rotates in the bearing without pivot shaft bearing 23 rotating in the slots 14 and on the latch 15 which may comprise two latch plates 25 and 26 interconnected by rods 27 and 28 and it holds the pivot shaft bearing 23 in the up position to enable the rotating section 12 to be rotated from the vertical to the horizontal position and vice versa.A latch bolt 16 is used to hold the latches in the vertical position and to assist in placing the column in the vertical locked position.

Latch stop 17 stops the latch in the forward position and assists in carrying the load when turning the rotating section. Latch 15 may turn about rod 28.

Operation of the device is achieved by attaching a raising and lowering mechanism such as a hydraulic cylinder or a jacking screw 18 to clevis points 19 and 20. To lower the mast 22 the latch screw 16 is released to allow the latch 15 to fall against the latch stops 17 when the rotating section is raised to its uppermost position. The uppermost position of the rotating section 12 is reached when the pivot shaft bearing 23 reaches the top of the slots 14 in the base 11. Expanding the raising and lowering device 18 raises the mast and allows the latch 15 to fall against the stops 17. The raising and lowering mechanism 18 is then operated to retract and the mast 22 will rotate to the horizontal position.

Expanding the raising an lowering mechanism 18 rotates the mast 22 to the vertical position, the latches are then returned to the vertical position by means of the latch screw 16, the mast is lowered to its down position by retracting the raising and lowering mechanism 18 and the safety locking screws 21 fixed in position. The raising and lowering mechanism 18 is then removed and the mast apparatus ready for use.

In the above there is described a device for use in raising and lowering a mast from the horizontal to the vertical positions by means of a pivoting action.

The device is self locking in the vertical position to ensure the joint is stable and will not pivot until a rotating device is attached and operated. Safety locking bolts are provided as an added precaution to prevent accidental movement from the vertical locked position.

The invention is for use in applications where equipment is to be installed at various heights above ground level. Applications for the invention would include lighting used in areas such as sports fields, work places, roads, highways and airports; advertising signs; radio and television transmitting and receiving antennae etc, where ease of access for installation and maintenance are of importance.

The equipment to be mounted to the device is attached either directly to or mounted on a column attached to the rotating section of the device.

Equipment installation is carried out at ground level when the rotating section is set in the horizontal position. Maintenance of the equipment is also carried out in this horizontal position thus eliminating the necessity for the use of ladders, tower cranes, climbing rungs etc, thus avoiding problems associated with working at heights.

The raising and lowering from the horizontal to the vertical positions is accomplished by attaching either an hydraulic ram with its associated power pack to operate the ram in the expand or retract positions or by a mechanical screw jack either hand or power operated.

Various changes and modifications may be made to the embodiments described without departing from the scope of the present invention.

Claims (11)

1. A folding mast able to be lowered comprising: a bottom support section; an upper section; a pivot means interconnecting the bottom and upper sections; and a latch means operative to permit angular movement of the upper section about the pivot; the upper and lower sections being locked in a first position against relative angular movement; the upper section being movable vertically from the first position to a second position whereat relative angular movement is permitted; the upper section being retained in the second position by the latch means when the upper section may be lowered; and the latch means comprising an overbalanced member arranged to fall under gravity to a locking position when the upper section is in its unlocked state.

2. A folding mast as claimed in claim 1 wherein elongate upper and lower sections are telescopically interengaged in a first position against relative angular movement, in which position the upper section may move axially relative to the lower section to the second position and the latch means prevents relative movement back to the locked position unless it is held in a disengaged state.

3. A folding mast as claimed in either of- claim 1 or claim 2 wherein the pivot means comprises a pivot shaft passed through the upper and lower sections, the pivot shaft passing through a slot in the lower section, the slot being extended vertically to enable movement of the pivot shaft with the upper section as the upper section moves to its second position.

4. A folding mast as claimed in claim 3 wherein the latch means moves beneath the pivot shaft in the second position to prevent movement of the pivot shaft and the upper section back to the first position.

5. A folding mast as claimed in either one of claim 3 or claim 4 wherein the latch means comprises an over balanced pivoted latch rested on the pivot shaft which moves under gravity between a first open position out of the path of the pivot shaft which is defined for the pivot shaft by the slot and a second closed position in the path of the pivot shaft.

6. A folding mast as claimed in any one of the preceding claims wherein the latch is fitted with a bolt means whereby it may be retrieved from its position whereat the upper section is locked against movement.

7. A folding mast as claimed in any one of claims 1 to 6 wherein the pivot shaft is passed through a cylindrical bearing the ends of which engage in the slots of the lower member and move there along with movement of the pivot shaft.

8. A folding mast as claimed in claim 7 wherein the cylindrical bearing is fitted at each end with end plates engaged in the slots in the lower member to lock the bearing against rotation.

9. A folding mast as claimed in any one of claims 1 to 8 wherein the upper and lower sections are provided with clevis points between which a ram may be fitted for lifting the upper section to its second unlocked position and then lowering it.

10. A folding mast substantially as hereinbefore described with reference to the accompanying drawings.

11. Any novel feature or combination of features described herein.