WO1994013916A1 - Improvements relating to gate opening mechanisms - Google Patents

Abstract

The invention provides a gate opening mechanism wherein a vehicle approaching a closed gate (10), for example of a field or forest where there is no power is used to displace liquid from a fluid displacement device (40, 42) and the displacement of that liquid is used to open the gate. This can be done by charging the displaced fluid into a tank (36) which descends under gravity and opens the gate, or it could be used to pressurise a pressure operated device such as an arm which in turn opens the gate. Arrangements are made to provide that the gate will return to the closed position automatically.

Description

Improvements Relating to Gate Opening Mechanisms

This invention relates to a gate opening mechanism which in particular has application in situations where gates are remotely located for example in the countryside in forestry land and the like, where power supplies are not available.

In such locations, gates are utilised to control the movement of animals such as sheep or cows or generally to provide barriers controlling the free movement of people and vehicles.

Where no power is available, it is necessary that these gates have to opened by hand and likewise closed by hand. If the gates are in encountered by people on foot, then there is no difficulty in opening and closing the gate but for people travelling in vehicle to encounter such gates, they must leave their vehicles open the gate, drive through and then reclose the gate and finally drive on. This is at best a nuisance for vehicle travellers, and at worst is a representation of a considerable loss of efficiency in the case of personnel such as farmers who may have to pass through such gate openings many times during the course of a working day.

The present invention seeks to provide a door opening arrangement which overcomes these disadvantages.

The present invention is based upon the utilisation of a fluid or vacuum for opening a gate, and whilst the opening of gates only is referred to in this specification, I do recognise that the invention may also have application to the actuation of other mechanisms and if the features of the invention are adopted in relation thereto I would take the view that the patent granted on this application ..would extend to any such application.

Liquid, for example, can be used in several ways to actuate a device which can open a gate. In one application, the weight of the liquid is used and the gate opening device is gravity actuated. In this case, a quantity of liquid is positioned so that it's gravitational effect operates the gravity actuating mechanism, and the gate opens. The gate opening device may be such as to lift the gate in the nature of a railway barrier arm, the gate being of suitable construction to operate in this manner, alternatively the gravity effect may be converted into a force causing the gate to swing open, where the gate is a swing opening type gate.

Secondly, the pressure in liquid may be utilised for operating a liquid pressure operated device such as a hydraulic ram or adaptation of a hydraulic ram, the movement of which is a result of the applied liquid pressure causes the gate to raise or swing as described above.

The invention also provides arrangements for closing of the gate in an automatic fashion. Where the gravity effect of a quantity of liquid is utilised for the opening of the gate, the automatic closing may be achieved by allowing that liquid slowly to drain from a position in which the gravity effect applies, to a location where the gravity effect is eliminated. For example, if the quantity of liquid is placed in a tank which descends to give the gravity effect, the liquid may be allowed to drain from that tank passed a restrictor member or the like to a storage vessel so that the gravity effect gradually is eliminated. Where the gate is one which is raised by being pivoted upwardly, the weight of the gate may serve as the means for returning same to the initial closed position as the gravity effect of the quantity of liquid gradually is removed. In the case where the gate is a swinging gate, spring means or the like may be utilised for automatically returning the gate to the closed position as the gravity effect is removed by the draining away of the liquid as mentioned above.

Where the gate is displaced by the pressure in the liquid, the return of the gate may again be achieved by a spring or the like which forces the liquid out of the pressure actuator when the force causing the pressure is removed.

With all of the arrangements, a gate opening mechanism can be provided which does not require the local provision of power insofar as the opening mechanism can be put into effect by several means available at the location of the gate.

In a particularly simple arrangement, there may be provided at the location of the gate a reservoir of liquid and a container which a person arriving at the gate can fill and poor into a gravity tank to cause the gate to open, and in this arrangement there would be an automatic return mechanism as indicated above enabling the automatic return of the gate to the closed position by the draining back of the liquid.

Such an arrangement provides only a partial advantage however, because if it involves the manual manipulation of a container, the filling of same with liquid, and the pooring of that liquid into a gravity tank, then obviously the person arriving at the gate could simply open it manually. There would however be some advantage in that the person operating the mechanism would not have to close the gate as closing would be automatic. This could be of some advantage in a case where the person controlling the gate arrives at same in a vehicle because after opening the gate he can return to his vehicle and simply drive through when the gate is opened, leaving it to close automatically. The best advantage however lies where the person wishing to open the gate arrives in a vehicle and the opening of the gate is effected by using the vehicle mass to displace liquid from a suitable member either to charge a quantity of liquid into a gravity operating tank on the one hand, or to pressurise a gate actuator on the other hand.

In the first case, the vehicle may be adapted to drive over a member which contains liquid, and the weight of the vehicle pressurises the liquid to displace same to cause it to be charged into a gravity tank which in turn causes automatic opening of the gate. The vehicle driver can then drive through, the gate being opened without his having to leave the vehicle, and when he has driven through, the automatic return is operative to return the gate to the closed position. There is also an aspect of the invention which provides that the vehicle can cause automatic opening of the gate, but closing of same requires some manual operation on the part of the driver. This may be achievable by pulling a lever or some other device located at the downstream side of the gate to release catch which causes automatic return of the gate.

In a particular example, the member over which the vehicle runs is an elongated flexible tube containing liquids. As the vehicle arrives at the gate, the driver causes the wheel of the vehicle to ride along the flexible tube which preferably lies lengthwise of the road or track, so the liquid therein is pumped from the tube upwardly into a gravity tank. This tank is carried by a pivotable lever which swings under the gravitational effect of the addition of the water to the tank, against a counterbalance mass at the other end of the lever, and the pivoting of the lever effects . pulling on a cable which is wrapped around a gate post, the gate post being mounted for the pivotal movement about a vertical axis and carrying the gate style. The result is that the gate swings open and the driver can drive through. The swinging open is against the tensioning of the return spring and when the driver has driven through, the mechanism is designed so that the liquid charged quickly into the tank by virtue of the vehicle's movement will drain back slowly into the flexible tube whereby the gravitational effect will be removed and the counterbalance and return spring cause the gate to swing back to the closed position.

In an alternative arrangement the member over which the vehicle runs is a plate which lies transversely of the road or track along which the vehicle travels towards the gate. In such a case for example the depression of the plate by a vehicle may pump liquid in a flexible tube directly into the gravity tank so that the gate may be opened as described above. Alternatively when the aforementioned plate is depressed by the vehicle wheels liquid in a flexible tube beneath the plate may be pumped upwardly to a first tank where it is initially retained. On reaching the gate the driver can then pull a chain or lever at the side of the road or track to actuate the release of a fixed volume of liquid through an openable valve in the said first tank. The liquid thus released flows under gravity through an interconnecting pipe to the gravity tank. The gate opening mechanism is then effected as discussed in the preceeding paragraph.

Upon exiting the gravity tank liquid passes through an additional one way valve before returning to the tube. This one way valve prevents the passage of liquid directly to the gravity tank. In this instance the amount of liquid pumped to the first tank may be greater than that which is required to operate the gate opening mechanism such that after the chain or lever has been pulled surplus liquid remains in the. first tank and may be released by a subsequent driver.

In this instance only a single plate would be required as a vehicle travelling towards the gate from the side of the gate remote from the plate would be able to pull a chain or lever on his side of the gate to open said gate and then by subsequently passing over the plate recharge the first tank for further use. Preferably in such an example said first tank contains a volume of liquid which is at least double that of the fixed volume released by actuation of the chain/lever.

It is preferred that the gate is also manually openable and closeable by pedestrians.

Preferably, the gate is provided with a spring damper arrangement so that at the end of its swinging stroke in either direction it will abut a damper spring to retard its movement smoothly down to zero.

In an alternative arrangement, the pivotal action of the lever is used to raise the gate where the gate is of the lifting type.

Finally, the gate may be provided with a catch which locks the far side of the gate to a gate post at the other side of the road or track, the catch is automatically released by the gate opening mechanism. The catch is to prevent the gate from being pushed open by animals or the like accidentally.

Where the displacement of the liquid by the vehicle is used to pressurise an actuator, the actuator can simply be directly coupled to the gate in appropriate fashion to cause it to swing open. In this arrangement, it may be necessary to have a pressure release valve to allow the escape of excess liquid into a holding tank from which it drains back into the actuator member in due course. Thus, if the vehicle moves over the actuator member and the liquid is displaced into the actuator, more than enough liquid to operate the actuator may be displaced, and provision has to be made for overspill. When the vehicle has passed through the opening gate, return of the actuator and the liquid in the system is achieved by the force of the return spring on the gate and the liquid is returned through a restrictor so that closing of the gate does not take place too quickly.

In the preferred embodiments it can be seen therefore that a vehicle is used for the displacement of liquid and the displacement of that liquid is used for opening the gate. The liquid returns to the initial position, preferably through a restrictor so that return of the gate is not too quick, which will enable the vehicle driver to drive through the gate and carry on without stopping knowing that the gate will close automatically and in controlled fashion. Obviously the gate must be opened for sufficient time to enable the driver to pass through but this time can be established by trial and error.

The advantage of all of the embodiments is that at least some of the manual operations or gate opening/closing take place automatically and in the preferred case the driver of a vehicle will not be obliged to leave his vehicle at all upon arriving at a gate to be opened. This is achievable furthermore in locations where no power to operate the gate is available.

The liquid which is usable for operating the mechanism preferably is water, and therefore the mechanism can be inexpensively maintained. Where the mechanism is usable in a region where freezing may occur, it is preferred that the water should be appropriately treated with antifreeze material to prevent freezing of the water from taking place.

It is clear that other fluids such as compressed air and or indeed a vacuum could be used to actuate a gate opening mechanism of the type described in this invention.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein:-

Fig. 1 is a side view showing a gate and a gate opening mechanism according to the embodiment of the invention;

Fig. 2 is a perspective view of the mechanism shown in Fig. 1;

Fig. 3 is a sectional view of a gravity tank shown in Fig. 2;

Figs. 4 and 5 are view illustrating how the gate latch is operated; and

Fig. 6 is a sectional view of the gate post shown in Fig. 2 but also showing a movement damper arrangement.

Fig. 7 is a plan view of an alternative means of supply of liquid to the gravity tank.

Referring to the drawings, and firstly to Fig. 1, a swing gate is indicated by the reference numeral 10, and it is shown as being made up of a pair of gate styles 12 and 14. The gate could take any convenient form, and although the gate 10 is swingable about a gate post 16, it could be designed to be raised in the nature of a level crossing barrier. A second gate post 18 at the other side of the opening which is closed by the gate, and the gate furthermore carries a spring loaded gate bolt 20 which engages in an appropriate bolt aperture to keep the gate closed so that it will not accidentally be opened by animals or the like. Bolt 20 is of the type which will spring into locking engagement with the post 18 as the gate closes but needs to be retracted to allow the gate to be opened.

The opening of the gate 10 is controlled by a gate opening mechanism indicated generally in Fig. 1 by reference numeral 22, and this mechanism is shown in greater detail in Fig. 2 to which reference is now made.

In Fig. 2 the gate post 16 about which the gate is swingable is shown, and part of the gate 10 is shown in full lines in the closed position, and in dotted lines in the opened position.

The gate opening mechanism comprises a fixed support post 24 which is located side by side with the post 16, and at its top end it is bifurcated to define a pair of lugs 26 and 28 which form supports for a pivot pin 30 which carries in pivotal fashion a swing lever 32. The lever 32 has at one end a counterbalance weight 34, and at the other end it carries two gravity displacement tanks 36 and 37 for the receipt of water as will be explained hereinafter.

Additionally, lever 32 has an operating arm 34 which extends upwardly, and to which is attached the end of an operating wire or cord 33. Cord 33 is wrapped around the top end of the post 16 as shown at 38.

Tank 36 is fed with water from flexible tube 40 and tank 37 is fed with water from flexible tube 42. Tubes 40 and 42 lie on the ground, and extend along the edge of the road or path leading to the gate, but in opposite directions.

It is to be understood that the tanks 36,37 and tubes 40,42 are identical. As shown in Fig. 3, inside the tank 36 is a restrictor plate 46 which is pivotally mounted at location 48 so that the plate 46 can pivot between the full line open positions shown in Fig. 3, and the dotted line restricting position 50 shown in Fig. 3.

Figs. 4 and 5 show a latch operating mechanism for releasing the bolt 20 when the gate is to be opened, and referring to these figures, it will be seen that the latch mechanism includes an operating rod 52 which extends along the top of the gate, and that rod is slidably supported in a bracket 54 passed with the gate style member 12. A spring 56 acts between a collar 58 on rod 52 and the bracket 54 so as to urge the rod 52 to the door bolt closing position.

At its end adjacent post 16 the rod 52 has a pair of stop members 60 and 62 between which an operating pen 64 which radiates from the post 16 and is fast therewith passes between.

Fig. 6 shows that the post 16 furthermore is provided with a damper plate 66 having an aperture through which a curved guide bar 68 passes. The guide bar 68 is supported by a pair of end stops 70 and 72 which are in fixed position, and the bar 68 furthermore carries damper springs 74 and 76 as shown.

For the operation of the device, assume that the gate is in the closed position shown in Fig. 1. A vehicle approaches the gate and requires that it be opened and to do this the driver drives so that one of his wheels runs on the flexible pipe 40 or 42 depending upon the direction in which the driver approaches the gate. As this takes place, water is displaced from, for example, pipe 40 into gravity tank 36. This tank starts to fill with water and as it does so it becomes heavier. Its gravitational effect therefore swings the lever 32 in an anticlockwise direction shown in Fig. 2 so that the post 16 starts to turn by virtue of the movement of the cable 36. When the post starts to turn, the pin 64 operates on stop 60 and pulls the latch bar 52 to the left in Fig. 1 thereby releasing the bolt 20 and the continued movement of the tank 36 now causes the gate to swing to the opened position shown in Fig. 2 in dotted lines.

As the water is charged into the tank 36, the restrictor plate 46 is immediately raised to the open position so that there is no restriction to the inflow of water and the mechanism therefore responds quickly. The stop 70 controls the extent to which the door opens, and the spring 74 acts as a damper to retard and decelerate the movement as the gate moves to the final open position. The spring 76 in fact performs the same function as the gate closes.

The driver of the vehicle can now drive through without having to leave his vehicle, and he can continue on his journey because the mechanism is set automatically to control the closing of the door in a restricted manner.

This happens in that the restrictor plate 46 in the tank 36 is connected to a float 78 which is the means for causing the blade 46 to lift. Assuming that the water fills the tank 36 to level A, the restrictor plate 46 will remain in the fully opened position until the level sinks to that indicated by level B, being the position of which the float will then start to sink as the level falls. As the level falls so the plate 46 closes to a more restricted position, and return.of the liquid to the tube 40,42 is throttled and the door will close in a controlled fashion.

To this end, there is a return spring 79 as shown in Fig. 2 which wraps around the post 16 and is anchored to a post bearing 80, said post bearing 80 being supported on the fixed post 24 by an arm 82. There is a second post bearing 84 supported by an arm 86 which is also connected to the fixed post 24.

Fig. 7 shows an alternative arrangement comprising tanks 39 and 44, tubes 45, 47 and 49, plate 51 and lever 53. In use when a car passes over plate 51, water in tube 45, which extends beneath plate 51,is pumped into tank 39 which stands on post 39A. Upon reaching the gate 10 the driver merely has to open his window and pull lever 53 or 53A (depending on which side of the gate is being approached) which actuates the release of a fixed amount of water through valve 55 in tank 39. The released water passes through pipe 47 and into gravity tank 44 thereby actuating the gate opening mechanism as described above.

Upon leaving gravity tank 44 through a restrictor of the type described above the water passes along pipe 49 and through one way valve 57 before returning to pipe 45. One way valve 57 prevents water from passing directly to the gravity tank 44 by way of pipe 49 upon the depression of the plate 51.

A driver who opens the gate by use of lever 53A restocks the contents of tank 39 by depressing plate 51 after passing through the gate 10.

It can be seen therefore that an effective door opening control mechanism is provided, but it is to be stressed that this is only one embodiment of the invention and various other embodiments are possible as described herein. As mentioned, the displacement of the liquid may be used to operate an actuator such as a hydraulic ram for the opening of the gate, or alternatively a twin roller actuator which engages opposite sides of a flexible pipe for example as disclosed in British Patent No 1358361 may be used, except that the roller pair is mounted so as to move in a circular path to effect swinging of the gate.

It should be noted that the utilisation of a flexible pipe as the liquid displacement means should preferably be such that it will not be possible for the mechanism to be operated by an animal or a pedestrian walking on the flexible pipe. In this connection it is preferred that the flexible pipe be supported on a rigid base such as a concrete strip to ensure that there will be effective compression of the pipe and therefore effective displacement of the liquid.

Instead of the gate being adapted to swing open, it may be arranged to be pivoted upwards in the manner of a pedestrian crossing.

The appropriate amount of liquid will have to be charged into the container when the gate is opened by charging liquid into a displacement tank as described in relation to the drawings, but typically a tank may be adapted to receive three gallons of liquid, with the minimum amount of liquid to operate the mechanism being in the order of one gallon. The mechanism may be designed such that the gate remains opened for about thirty seconds before automatically returning to the closed position.

The gate catch which has been described as a mechanical catch, but it could be operated hydraulically by leading a hydraulic pipe directly to the catch mechanism. Any suitable liquid may be used for the device such as a water/antifreeze mixture or an oil may be used.

The gate mechanism should be suitable for operation by a pedestrian to enable pedestrians to pass through the gate, and in relation to the embodiment described, the pedestrian would simply release the gate catch and open the gate to the extent required. The spring will return the gate to the closed position.

Any suitable form of counterbalance may be used for the mechanism and in one example a counterbalance comprises a hollow body which is filled with an appropriate amount of sand through an aperture therein, the aperture subsequently being closed by a closure device such as a rubber bung.

The mechanism of the invention should be designed so as to require very little maintenance and its use may in some cases avoid the need for cattle grids. It is also to be noted that this invention is clearly advantageous for disabled drivers.

It is to be understood that this invention may also use other suitable fluid or vacuum means to actuate the gate opening mechanism.

The gate opening mechanism described in this invention has the added advantage that it can fitted to an existing gate as well as on a new gate.

Claims

1. A gate control mechanism comprising a tank for liquid mounted to descend by gravity when a predetermined amount of liquid is charged thereinto, and said descending is used to open or close a gate.

2. A mechanism according to claim 1, wherein the descending of the tank is used to open the gate.

3. A mechanism according to claim 2, wherein the tank has an outlet from which the liquid drains and counterbalance means causes the gate to close as the liquid drains from the tank.

4. A mechanism according to claim 3, wherein the counterbalance means comprises the gate itself.

5. A mechanism according to claim 3, wherein the descending of the tank causes the gate to swing open by means of a transmission between the tank and the gate, and the counterbalance comprises a weight on one arm of a pivot level of which the other arm carries the tank.

6. A mechanism according to claims 3, 4 or 5, wherein the said outlet is restricted to control the rate at which liquid drains therefrom thereby controlling the rate of closing of the gate.

7. A mechanism according to claim 6, wherein said outlet is restricted by a float controlled valve which restricts draining of the liquid only when there is less than said predetermined amount of liquid in the tank.

8. A mechanism according to any preceding claim including a delivery means actuable by being driven over by a vehicle to pump liquid from the delivery means to the tank said delivery means being located so that it can be driven over by a vehicle approaching the gate to operate the mechanism.

9. A gate opening control mechanism wherein a liquid displacement device adopted to be driven over by a vehicle to cause displacement of liquid therefrom is hydraulically coupled to a mechanical gate opening means responsive to the displacement of said liquid.

10. A mechanism according to claim 9, wherein the liquid displacement device comprises a flexible tube which in use is placed in a position in which it is presented so that it can be run over by a vehicle approaching the gate.

11. A mechanism according to claim 9, wherein the liquid displacement device comprises a flexible bag or bellows and a plate, arranged in use to be positioned so that the bag or bellows lies under the plate, which in turn is adapted to be positioned to be driven over by a vehicle approaching the gate.

12. A mechanism according to claim 9, 10 or 11, wherein the mechanism comprises two liquid displacement devices respectively for location to opposite sides of the gate so that the gate can be opened by a vehicle approaching the gate from either side.

13. A mechanism according to any of claims 9 to 12, wherein the gate opening means comprises a liquid pressure operated actuator.

14. A mechanism according to claim 13, wherein the actuator comprises a liquid pressure operated ram.

15. A mechanism according to claim 13, wherein the actuator comprises a pair of rollers which nip a tube into which the displaced liquid is forced to displace said pair of rollers which in turn displace the gate to open same.

16. A mechanism according to any one of claims 9 to 13 including means for automatically closing the gate in a controlled manner.

17. A mechanism according to claim 16, wherein said means for automatically closing the gate comprises means for returning the liquid to the liquid displacement device through a restricter.

18. A mechanism according to any preceeding claim wherein the gate may also be manually opened and closed.

19. A gate control mechanism comprising a fluid displacement or vacuum producing device adapted to be driven over by a vehicle on said vehicles approach to the gate to cause fluid displacement or vacuum production which is used to open the gate.

20. A gate opening control mechanism substantially as any of the embodiments hereinbefore described with reference to the accompanying drawings.