WO2009115815A1

WO2009115815A1 - Folding leaf gate

Info

Publication number: WO2009115815A1
Application number: PCT/GB2009/000748
Authority: WO
Inventors: David Michael Ashby; Peter Malcom Philip Hylton
Original assignee: Eagle Automation Systems Ltd
Priority date: 2008-03-20
Filing date: 2009-03-19
Publication date: 2009-09-24
Also published as: GB0805283D0; GB2458510B; GB2458510A; GB2458510B8

Abstract

A folding leaf gate (1) is formed by a post hung section (2) hingedly mounted on a gate post (4) and a one leaf section (3) hingedly mounted in concertina fashion to the post hung section (2). A first hydraulic rod and piston arrangement (8) rotates the post hung section (2) and a second hydraulic rod and piston arrangement (15) rotates the leaf section (3) by means of a link chain (20), which is driven linearly by the second hydraulic rod and piston arrangement (15) and which causes rotation of the leaf section (3).

Description

FOLDING LEAF GATE

Field of the Invention

This invention relates to folding leaf gates, and particularly, though not exclusively, to folding leaf gates which can be mounted without the need for tracks to maintain the orientation of the various section of the gate as they open and close.

Background of the Invention Folding leaf gates are generally formed of a pair of post hung sections, each hingedly mounted on an opposite gate post so as to open and close a gateway defined between the gate posts. In order to allow gateways of larger widths to be opened and closed, the post hung sections are each provided with one or more leaf sections, which are hingedly mounted to the post hung sections. Such an arrangement also enables the overall extent of the gate in the open position to be substantially reduced as compared to the width of the gateway. The post hung sections usually move 90° between the open and closed positions. At the same time, however, the leaf sections would need to move through 180°. In the open position, the leaf section(s) rests parallel to the post hung section, in a concertina fashion.

It will be appreciated that, in order for the leaf section to swing through 180° and to maintain the correct orientation to the post hung section it must be constrained in some way in order to move correctly relative to the post hung section. A freely hinged and hanging leaf section would not move as required. A common way to provide the constraints on the leaf section(s) is to mount a small wheel on an edge of the leaf section opposite to the edge that is hinged to the post hung section. The wheel is then constrained to move within a track, which may be provided in the ground across the gateway, or, in some cases, above the gateway. In this way, when the post hung section is moved, for example from a closed to an open position, the wheel is constrained to remain in the track, thereby constraining the edge of the leaf section to remain in the plane of the gateway, so that, as the post hung section rotates by 90°, the leaf section has to rotate by 180° so as to maintain its hinged edged attached to the post hung section as it swings open and its opposite edge within the plane of the gateway.

However, in some installations, it is undesirable or difficult to have a track fitted into the ground across the gateway, especially if the ground is uneven. Similarly, it may be undesirable to have an overhead track fitted because this would limit the height of vehicles that could pass underneath it, and it may be considered to be unsightly.

Folding leaf gates have therefore been developed which are trackless. One such trackless folding leaf gate is known from European Patent No. 1 595 050 (Cova Security Gates Ltd) in which several embodiments of trackless folding leaf gates are described. In a first embodiment, there is provided a rod rotatably mounted adjacent the gate post on which the post hung section is mounted. The rod is arranged to rotate about an axis which is parallel to the axis about which the post hung section rotates, so that the other end of the rod forms an acute angle with the other end of the post hung section at which the leaf section is mounted. The other end of the rod is provided with a rack, the teeth of which engage with teeth on a pinion, which is mounted on the leaf section at its axis of rotation. Thus, as the post hung section is swung open, the rack on the rod moves linearly against the pinion, which is caused to rotate, thereby rotating the leaf section. Clearly, a mechanism for keeping the rack and pinion in engagement is also necessary.

In a second embodiment, the pinion is replaced by a driven sprocket wheel, which is, of course, mounted to rotate on the same axis of rotation as the hinges mounting the leaf section to the post hung section. A drive sprocket Wheel is provided on the post hung section mounted so as to rotate with the post hung section and rotating on the same axis of rotation as the post hung section. The drive sprocket wheel is provided with twice as many teeth as the driven sprocket wheel so that a drive chain, which is provided around the drive and driven sprocket wheels, causes the driven sprocket wheel to rotate twice the angle that the drive sprocket wheel does when the post hung section is opened and closed. Other embodiments described in this patent specification replace the chain drive arrangement by a bevel gear arrangement and describe various mechanisms for driving the post hung section to open and close. Another trackless folding leaf gate is described in US Patent No. 4,699,197 (Jerry Hamrick, et al), in which a drive rod is mounted along the width of the post hung section so as to drive a hinge mounting the leaf section.

Such trackless folding leaf gates require a precise relationship to be maintained between the post hung section and the leaf section(s) in order that they rotate together at the appropriate rates to open and close together. This requires complicated drive mechanisms that rely on a relationship between movement of the post hung section to control movement of the leaf section(s). This can be complicated, which, in turn can be difficult to install and costly.

Brief Summary of the Invention

The present invention therefore seeks to provide a folding leaf gate that overcomes, or at least reduces the above-mentioned problems of the prior art.

Accordingly, in a first aspect, the invention provides a folding leaf gate comprising a post hung section for hingedly mounting to a gate post and at least one leaf section, the or each leaf section being hingedly mounted in concertina fashion to the post hung section, a first linear actuator for rotating the post hung section, a second linear actuator, and a linear-to-rotatable motion converter having a first, linear part and a second, rotatable part, wherein the second, rotatable part of the converter comprises a first wheel mounted on the axis of rotation of the leaf section, a second wheel being mounted on the post hung section spaced from the first wheel, and the first, linear part of the converter comprises a continuous web moving around and between the two wheels, the second linear actuator comprises a first end coupled to impart linear motion to the continuous web, which, in turn causes rotational movement of the first wheel for rotating the leaf section, when operated.

In a preferred embodiment, the web comprises a link chain and the first and second wheels comprise sprocket wheels around which the link chain moves, the first end of the second linear actuator being connected to the link chain to move it linearly.

Alternatively, the web comprises a belt, the first end of the second linear actuator being connected to the belt to move it linearly.

The second wheel may be an idler wheel provided to enable the web to move, but requiring no particular size or position. Preferably, the first actuator comprises a rod and piston arrangement having a first end for rotatable mounting to the gate post at an axis of rotation adjacent to an axis of rotation of the post hung section, and a second end for engaging the post hung section to rotate it, when operated. Preferably, also, the second linear actuator comprises a rod and piston arrangement, having a first end coupled to impart linear motion to the continuous web and a second end mounted on the post hung section.

A guide arrangement may be provided for guiding the first end of the rod and piston arrangement in a linear direction in a linear direction parallel to that of the first linear part of the converter.

The first linear actuator may be pneumatic, hydraulic or electromechanical and/or the second linear actuator may be pneumatic, hydraulic or electro-mechanical.

In one embodiment, the folding leaf gate further comprises a pneumatic, hydraulic or electro-mechanical pump coupled to the first and second linear actuators and a controller for controlling the pump and the actuators.

In an alternative embodiment, the second linear actuator comprises a rod arrangement having a first end coupled to impart linear motion to the continuous web and a second end for rotatable mounting to the gate post on the axis of rotation of the first linear actuator. Preferably, a guide arrangement for guiding the first end of the rod in a linear direction parallel to that of the continuous web may be provided.

A linear stroke of the rod of the second linear actuator is preferably equivalent to 180° rotation of the leaf section. According to a second aspect, the invention provides a folding leaf gate comprising a post hung section for hingedly mounting to a gate post and at least one leaf section, the or each leaf section being hingedly mounted in concertina fashion to the post hung section, a first actuator for rotating the post hung section and a second actuator for rotating the at least one leaf section independently of the rotation of the post hung section.

In one embodiment, the first actuator is a first linear actuator, which preferably comprises a rod and piston arrangement, having a first end for rotatable mounting to the gate post and a second end for engaging the post hung section to rotate it, when operated, and may be pneumatic, hydraulic or electro-mechanical.

The second actuator is preferably a second linear actuator, and may comprise, for example, a rod and piston arrangement having a first end mounted on the post hung section and a second end for rotating the leaf section hingedly mounted to the post hung section, when operated.

In a preferred embodiment, the folding leaf gate further comprises a linear-to-rotatable motion converter having a first, linear part and a second, rotatable part, wherein the second end of the rod and piston arrangement comprises an end of the rod coupled to impart linear motion to the first linear part of the converter, and the second rotatable part of the converter being mounted to impart rotation to the leaf section, when operated.

Preferably, the second, rotatable part of the converter comprises a first wheel mounted on the axis of rotation of the leaf section, a second wheel being mounted on the post hung section spaced from the first wheel, and the first, linear part of the converter comprises a continuous web moving around and between the two wheels, whereby linear movement of the rod causes linear movement of the web, which, in turn causes rotational movement of the first wheel for rotating the leaf section. In one embodiment, the web comprises a link chain and the first and second wheels comprise sprocket wheels around which the link chain moves, the end of the rod being connected to the link chain to move it linearly.

Alternatively, the web comprises a belt, the end of the rod being connected to the belt to move it linearly. The second wheel may be an idler wheel provided to enable the web to move, but requiring no particular size or position.

A linear stroke of the rod of the rod and piston arrangement is preferably equivalent to 180° rotation of the leaf section.

The second linear actuator may be pneumatic, hydraulic or electro- mechanical.

In another embodiment, the converter comprises a rack and pinion arrangement, the rack being connected to the end of the rod, and the pinion being mounted to the leaf section, whereby linear movement of the rod causes linear movement of the rack, which, in turn causes rotational movement of the pinion for rotating the leaf section.

In a still further embodiment, the second actuator is a second rotary actuator mounted for rotating the leaf section(s), when operated, and may be, for example, a hydraulic motor.

The folding leaf gate preferably further comprises a controller for controlling the first actuator and the second actuator such that the first and second actuators can be operated independently of each other whereby the leaf section can be rotated without rotation of the post hung section or the post hung section can be rotated without separate rotation of the leaf section so that both sections rotate together about the gate post.

Brief Description of the Drawings

Several embodiments of the invention will now be more fully described, by way of example, with reference to the drawings, of which:

FIG. 1 shows a schematic front elevational view of a folding leaf gate according to a first embodiment of the invention in the closed position;

FIG. 2 shows a schematic plan view of the folding leaf gate of FIG. 1 ; FIGs. 3 - 5 show schematic diagrams of alternate ways of coupling and controlling actuators used in the first embodiment of the folding leaf gate of FIG.

1 ;

FIG. 6 shows a schematic front elevational view of a folding leaf gate according to a second embodiment of the invention in the closed position;

FIG. 7 shows a schematic plan view of the folding leaf gate of FIG. 6; FIG. 8 shows a schematic front elevational view of a folding leaf gate according to a third embodiment of the invention in the closed position;

FIG. 9 shows a schematic plan view of the folding leaf gate of FIG. 8; FIG. 10 shows a schematic plan view of the folding leaf gate of FIG. 8 in a part open position; and FIG. 11 shows a schematic plan view of the folding leaf gate of FIG. 8 in a fully open position.

Detailed Description of the Drawings Thus, as shown in the Figs. 1 and 2 of the drawings, a folding leaf gate 1 has a post hung section 2 and a leaf section 3. The post hung section 2 is rotatably mounted on a gate post 4 by means of hinges 5. The leaf section 3 is rotatably mounted to the post hung section 2 by means of hinges 6. The post hung section 2 and the leaf section 3 are shown in the closed position. In order to open, the post hung section 2 is caused to swing 90° (downwards as shown in Fig.2) and the leaf section 3 is caused to swing 180° (upwards as shown in Fig. 2) in the direction of arrow 7. Clearly, although only one leaf section is shown, it will be appreciated that more than one such leaf section could be provided, with each leaf section being mounted to the preceding adjacent leaf section in a concertina fashion.

In order to rotate the post hung section 2, a hydraulic rod and piston arrangement 8 is provided. The rod and piston arrangement 8 incorporates a cylinder 9 having one end rotatably mounted by one end on a bracket 10 that is mounted to the gate post 4 so that an axis of rotation 11 of the rod and piston arrangement is positioned adjacent the axis of rotation 12 of the post hung section 2. An end of the rod 13 of the rod and piston arrangement 8 is rotatably engaged on a spigot 14 attached to the post hung section 2. Thus, when the hydraulic rod and piston arrangement 8 is actuated by means of a hydraulic pump and controller (not shown in Figures 1 and 2), this causes the post hung section to be swung about its axis of rotation 12, whilst the rod and piston arrangement rotates about its axis of rotation 11.

In a similar manner, in order to rotate the leaf section 3, a second hydraulic rod and piston arrangement 15 is provided. The rod and piston arrangement 15 incorporates a cylinder 16 mounted to the post hung section 2. An end 17 of the rod 18 of the rod and piston arrangement 15 is attached to a link 19 of an endless link chain 20, which is arranged to move about a pair of sprocket wheels 21 and 22. The end 17 of the rod 18 is also attached to an annular guide member 35, which is arranged to slide reciprocatably on a guide post 34 mounted to the post hung section 2. Thus, the end 17 of the rod 18 is constrained to move backwards and forwards linearly moving the link 19 linearly backwards and forwards when the hydraulic rod and piston arrangement 15 is actuated by means of a hydraulic pump and controller (not shown in Figures 1 and 2). Sprocket wheel 21 is mounted in a non-rotatable fashion to the leaf section 3 to have a coincident axis of rotation to that of the leaf section 3. Sprocket wheel 22 is mounted on the post hung section 2 and is merely an idler wheel used to allow the link chain 20 to move about the sprocket wheels, without needing to have any other special size or position in relation to the sprocket wheel 21. Thus, the linear movement of the link 19, moved by the end 17 of rod 18, causes the link chain 20 to move and thereby rotate the sprocket wheel 21 , which causes the leaf section 3 to rotate.

As will be appreciated, and as shown in Figs. 1 and 2, since the post hung section 2 and the leaf section 3 rotate in opposite direction, when they are in the closed position, the rod 13 of arrangement 8 is in the extended position, whereas the rod 18 of arrangement 16 is in the retracted position. In order to open the folding leaf gate 1 , rod 13 is caused to retract, pulling the post hung section 2 open and rod 18 is caused to extend, pushing the link 19 linearly and causing the leaf section 3 to open. In order to close the gate 1 , the rod and piston arrangements are actuated in the opposite directions. However, it will also be appreciated that the rod and piston arrangements can be actuated independently of each other. Thus, for example, arrangement 8 can be actuated so that post hung section 2 remains closed, whereas arrangement 15 can be actuated to open the leaf section 3 only. This may be useful, for example, if only part of the gateway needs to be opened to let through only a pedestrian -or a bicycle or motor bicycle, without needing to open the whole gate 1. Of course, in such a case, perhaps, only one side needs to be opened, rather than both sides simultaneously.

It will be appreciated that although the rod and piston arrangements 8 and 15 were described above as being completely independent and having separate hydraulic pumps, it is possible for them to be coupled to a single hydraulic pump, as shown in Fig. 3. In this case, arrangement 15 is shown, as in Figs. 1 and 2, in the retracted position with rod 18 retracted into cylinder 16 and arrangement 8 is shown, as in Figs. 1 and 2, in the extended position with rod 13 extended from cylinder 9. A reversible motor/pump 23 is connected by a hydraulic line 24 to a full bore end of cylinder 16 and by a hydraulic line 25 to a full bore end of cylinder 9, a hydraulic line 26 being provided between annulus ends of the cylinders 9 and 16. Thus, when the motor/pump 23, which is controlled by means of a controller (not shown), pumps hydraulic fluid through hydraulic line 24 into the full bore end of cylinder 16 so as to force the rod 18 to start to extend from cylinder 16, hydraulic fluid is forced out from the annulus end of the cylinder 16 through hydraulic line 26 and into the annulus end of cylinder 9, where it forces rod 13 to retract into cylinder 9, causing hydraulic fluid to be forced out from the full bore end of cylinder 9 and into hydraulic line 25. When the motor/pump 23 is controlled to pump hydraulic fluid in the other direction, the opposite will, of course, occur.

It will however be appreciated that if the hydraulic rod and piston arrangements are configured in this fashion they cannot be actuated independently. Therefore, as shown in Fig. 4 electro/hydraulic control valves may used to control the flow of liquid. In this case, as in the embodiment of Fig. 3, a reversible motor/pump 23 is connected by a hydraulic line 24 to a full bore end of cylinder 16 and by a hydraulic line 25 to a full bore end of cylinder 9, a hydraulic line 26 being provided between annulus ends of the cylinders 9 and 16. In this embodiment, however, an electro/hydraulic valve 43 is inserted into hydraulic line 24 between the reversible motor/pump 23 and the cylinder 16 and an electro/hydraulic valve 44 is inserted into hydraulic line 25 between the reversible motor/pump 23 and the cylinder 9. A further electro/hydraulic valve 45 is inserted into hydraulic line 26. Each of the electro/hydraulic valves 43 and 44 are three port valves, with further hydraulic lines 41 and 42 extending between the electro/hydraulic valves 43 and 44 and electro/hydraulic valves 45, which is a four port valve. All of the valves are independently controllable from the controller (not shown) which also controls the motor/pump 23. Thus, if valves 43, 44 and 45 are controlled so as to isolate lines 41 and 42, the hydraulic circuit operates exactly as the one described above with reference to Fig. 3. However, when it is desired to operate arrangement 8 independently of arrangement 15, allowing either the post hung leaf or the leaf section to be moved independently of the other section, the valves 43, 44 and 45 are controlled appropriately. For example, by isolating line 41 and arrangement 9 but opening line 42 allows fluid to flow from motor/pump 23 into the full bore end of cylinder 16, causing arrangement 15 to move, with the fluid return being via part of line 26, line 42 and line 25. Pumping in the opposite direction with the valves in the same positions, simply reverses motion of arrangement 15. In order to actuate arrangement 8, but not arrangement 15, requires the valves to be controlled so as to isolate line 42 and arrangement 15 but opening line 41 , thereby allowing fluid to flow from motor/pump 23 into the full bore end of cylinder 9, causing arrangement 8 to move, with the fluid return being via part of line 26, line 41 and line 24. Fig. 5 shows a further alternate embodiment, similar to that of Fig. 4, in which the valves 43, 44 and 45 and lines 26, 41 and 42 are essentially replaced by a manifold block 31 and lines 28 and 29. In this case, the motor/pump 23 is hydraulically connected by hydraulic line 30 solely to the manifold block 31 , which is also connected to hydraulic lines 24, 28, 29 and 25. The manifold block 31 is provided with pressure balanced in-line flow restrictors and is controlled by means of a controller (not shown) to control the hydraulic fluid flow in a similar manner to that of Fig. 4 to permit either flow through a circuit formed by lines 24 and 28 through arrangement 15 or through a circuit formed by lines 25 and 29 through arrangement 9, or through both circuits either to actuate the arrangements independently or together.

Figs. 6 and 7 show a second embodiment of a folding leaf gate 1 , in which similar elements have the same reference numerals as in Figs. 1 and 2 and will not be further described here. In this embodiment, although the first rod and piston arrangement 8 is the same as previously described, the second arrangement 18, together with the link chain 20 and the sprocket wheels 21 and 22, is replaced by a hydraulic motor 32 mounted on the post hung section 2, with a rotor 33 arranged to have a coincident axis of rotation to that of the leaf section 3 and connected to the leaf section 3 to drive it to rotate. Again, rotation of the leaf section 3 can thus be made independent of rotation of the post hung section 2.

A third embodiment of the invention is shown in Figs. 8 to 11 , in which similar elements have the same reference numerals as in Figs. 1 and 2 and will not be further described here. In this embodiment, once again, the first rod and piston arrangement 8 is the same as previously described, but the second arrangement 18 is replaced, although the link chain 20 and the sprocket wheels 21 and 22 remain. A non extendible rod 36 is rotatably mounted by one end 37 on bracket 10 so that its axis of rotation is coincident with the axis of rotation 11 of the rod and piston arrangement 8. The other end 38 of the rod 36 is attached so as to drive the link 19 of endless link chain 20, which is arranged to move about the pair of sprocket wheels 21 and 22. The end 38 of the rod 36 is also connected to an annular guide member 39, which is arranged to slide reciprocatably on a guide post 40 mounted to the post hung section 2, and which is connected to link 19. Thus, when post hung section 2, rotates, it causes the end 38 of the rod 36 to move backwards and forwards on the guide post 40 and to rotate about the axis of rotation 11. As the end 38 of rod 36 moves linearly backwards and forwards, it moves the link 19 linearly backwards and forwards causing the link chain 20 to move linearly and thereby rotate the sprocket wheel 21 , which causes the leaf section 3 to rotate. As will be appreciated, since the post hung section 2 and the leaf section

3 rotate in opposite direction, when they are in the closed position, as shown in Figs. 8 and 9, the rod 13 of arrangement 8 is in the extended position, whereas the rod 36 is in the closed position, where its end 38 is as near to the gate post end of the guide post 40 as practical. As the post hung section 2 is opened, the end 38 of rod 36 is caused to move on guide post 40, pushing the link 19 linearly and causing the leaf section 3 to open. An intermediate position is shown in Fig. 10, where the end 38 of the rod 36, with the annular guide member 39, is approximately mid-way along the guide post 40, the post hung section 2 has rotated about 45° and the leaf section 3 has rotated about 90°. Fig. 11 shows the gate 1 in the fully open position where the post hung section 2 has rotated 90°, the leaf section 3 has rotated 180° and the end 38 of the rod 36, with the annular guide member 39, is at the opposite end of the guide post 40 to its position in Figs 8 and 9.

It will be appreciated that although only a few particular embodiments of the invention have been described in detail, various modifications and improvements can be made by a person skilled in the art without departing from the scope of the present invention. For example, an end leaf section (being one furthest from the gate post and nearest the centre of the gateway) can be provided with a guide wheel that fits into a closing stop in the centre of the gateway in order to help secure the gate in the closed position.

Claims

1. A folding leaf gate comprising a post hung section for hingedly mounting to a gate post and at least one leaf section, the or each leaf section being hingedly mounted in concertina fashion to the post hung section, a first actuator for rotating the post hung section, a second linear actuator, and a linear-to-rotatable motion converter having a first, linear part and a second, rotatable part, wherein the second, rotatable part of the converter comprises a first wheel mounted on the axis of rotation of the leaf section, a second wheel being mounted on the post hung section spaced from the first wheel, and the first, linear part of the converter comprises a continuous web moving around and between the two wheels, the second linear actuator comprises a first end coupled to impart linear motion to the continuous web, which, in turn causes rotational movement of the first wheel for rotating the leaf section, when operated.

2. A folding leaf gate according to claim 1 , wherein the web comprises a link chain and the first and second wheels comprise sprocket wheels around which the link chain moves, the first end of the second linear actuator being connected to the link chain to move it linearly.

3. A folding leaf gate according to claim 1 , wherein the web comprises a belt, the first end of the second linear actuator being connected to the belt to move it linearly.

4. A folding leaf gate according to any preceding claim, wherein the second wheel is an idler wheel provided to enable the web to move, but requiring no particular size or position.

5. A folding leaf gate according to any preceding claim, wherein the first actuator comprises a rod and piston arrangement having a first end for rotatable mounting to the gate post at an axis of rotation adjacent to an axis of rotation of the post hung section, and a second end for engaging the post hung section to rotate it, when operated.

6. A folding leaf gate according to any preceding claim, wherein the second linear actuator comprises a rod and piston arrangement, having a first end coupled to impart linear motion to the continuous web and a second end mounted on the post hung section.

7. A folding leaf gate according to claim 6, further comprising a guide arrangement for guiding the first end of the rod and piston arrangement in a linear direction in a linear direction parallel to that of the continuous web.

8. A folding leaf gate according to any preceding claim, wherein the second linear actuator is a pneumatic, hydraulic or electro-mechanical actuator.

9. A folding leaf gate according to any one of claims 1 to 5, wherein the second linear actuator comprises a rod arrangement having a first end coupled to impart linear motion to the continuous web and a second end for rotatable mounting to the gate post adjacent to the axis of rotation of the post hung section.

10. A folding leaf gate according to claim 9, further comprising a guide arrangement for guiding the first end of the rod in a linear direction parallel to that of the continuous web.

11. A folding leaf gate according to any one of claims 6 to 9, wherein a linear stroke of the rod of the second linear actuator is equivalent to 180° rotation of the leaf section.

12. A folding leaf gate according to any preceding claim, wherein the first linear actuator is a pneumatic, hydraulic or electro-mechanical actuator.

13. A folding leaf gate according to any preceding claim, wherein the first and second linear actuators are either pneumatic or hydraulic and further comprising a pneumatic or hydraulic pump coupled to the first and second linear actuators and a controller for controlling the pump and the actuators.

14. A folding leaf gate comprising a post hung section for hingedly mounting to a gate post and at least one leaf section, the or each leaf section being hingedly mounted in concertina fashion to the post hung section, a first actuator for rotating the post hung section and at least one second actuator for rotating the at least one leaf section independently of the rotation of the post hung section.

15. A folding leaf gate according to claim 14, wherein the first actuator is a first linear actuator.

16. A folding leaf gate according to claim 15, wherein the first linear actuator comprises a rod and piston arrangement, having a first end for rotatable mounting to the gate post and a second end for engaging the post hung section to rotate it, when operated.

17. A folding leaf gate according to either claim 15 or claim 16, wherein the first linear actuator is a pneumatic, hydraulic or electro-mechanical actuator.

18. A folding leaf gate according to any one of claims 14 to 17, wherein the second actuator is a second linear actuator.

19. A folding leaf gate according to claim 18, wherein the second linear actuator comprises a rod and piston arrangement having a first end mounted on the post hung section and a second end for rotating the leaf section hingedly mounted to the post hung section, when operated.

20. A folding leaf gate according to 19, further comprising a linear-to- rotatable motion converter having a first, linear part and a second, rotatable part, wherein the second end of the rod and piston arrangement comprises an end of the rod coupled to impart linear motion to the first linear part of the converter, and the second rotatable part of the converter being mounted to impart rotation to the leaf section, when operated.

21. A folding leaf gate according to 20, wherein the second, rotatable part of the converter comprises a first wheel mounted on the axis of rotation of the leaf section, a second wheel being mounted on the post hung section spaced from the first wheel, and the first, linear part of the converter comprises a continuous web moving around and between the two wheels, whereby linear movement of the rod causes linear movement of the web, which, in turn causes rotational movement of the first wheel for rotating the leaf section.

22. A folding leaf gate according to claim 21 , wherein the web comprises a link chain and the first and second wheels comprise sprocket wheels around which the link chain moves, the end of the rod being connected to the link chain to move it linearly.

23. A folding leaf gate according to claim 21 , wherein the web comprises a belt, the end of the rod being connected to the belt to move it linearly.

24. A folding leaf gate according to any one of claims 21 to 23, wherein the second wheel is an idler wheel provided to enable the web to move, but requiring no particular size or position.

25. A folding leaf gate according to any one of claims 20 to 24, wherein a linear stroke of the rod of the rod and piston arrangement is equivalent to

180° rotation of the leaf section.

26. A folding leaf gate according to any one of claims 19 to 25, wherein the second linear actuator is a pneumatic, hydraulic or electro-mechanical actuator.

27. A folding leaf gate according to 20, wherein the converter comprises a rack and pinion arrangement, the rack being connected to the end of the rod, and the pinion being mounted to the leaf section, whereby linear movement of the rod causes linear movement of the rack, which, in turn causes rotational movement of the pinion for rotating the leaf section.

28. A folding leaf gate according to any one of claims 14 to 17, wherein the second actuator is a second rotary actuator mounted for rotating the leaf section(s), when operated.

29. A folding leaf gate according to claim 28, wherein the second actuator is a hydraulic motor.

30. A folding leaf gate substantially as hereinbefore described with reference to the drawings.