AU2685095A

AU2685095A - Apparatus for opening and closing a gate

Info

Publication number: AU2685095A
Application number: AU26850/95A
Authority: AU
Inventors: Bruce Malcom Bisdee; Stuart Macdonnell
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-06-13
Filing date: 1995-06-12
Publication date: 1996-01-05
Also published as: WO1995034736A1

Description

APPARATUS FOR OPENING AND CLOSING A GATE

BACKGROUND OF THE INVENTION

The present invention relates to apparatus for opening and closing a gate or door or similar barrier. As used herein, the term "gate" includes doors and similar barriers.

Over the last century or so, a huge number of mechanisms have been invented to overcome the problem of opening and closing a gate by automatic means i.e. without leaving the vehicle.

However, the practical difficulties of designing a reliable mechanism for this purpose are considerable:- most of the gates which it is desirable to open automatically are large and heavy, and must be opened fully and latched securely both in the "open" and "closed" positions. Thus, the mechanism must be capable of rotating a substantial load about a fixed pivot (the gatepost), and holding the gate open, and then holding the gate closed. In the past, must such mechanisms involved a relatively large number of moving parts, and because of the high loadings in use, wear was heavy and the mechanism soon wore out or became unreliable.

Another problem with previously proposed mechanisms is the high cost of manufacture and installation, which limits their usefulness since many potential users are not willing to pay high prices for such mechanisms.

It is an object of the present invention to provide apparatus for opening and closing a gate which is relatively inexpensive to manufacture, reliable in use, and contains a minimum of moving pans.

SUMMARY OF THE INVENTION

The present invention provides apparatus for opening and closing a gate, including an elongate member arranged to support one end of a gate, as hereinbefore defined, such that said gate can pivot between an open position and a closed position, characterised by a cam follower and a co- acting cam track, formed on a body, one of the cam follower and the cam track being connected to the elongate member and the other of the cam follower and the cam track being connected to the gate, the cam track and the cam follower being shaped such that as the cam follower is moved along the cam track in either direction from a central region of the cam track, the cam follower and said body are moved apart.

Preferably, the cam track is a part-circular cam track which provides two raised portions one on each side of a lower portion.

Desirably, said cam track is rotatable relative to said cam follower by means of a remotely- controlled electric motor; and said cam follower being free to roll along said cam truck under gravity.

DESCRIPTION OF DRAWINGS

By way of example only, a preferred embodiment of the present invention is described in detail with reference to the accompanying drawings, in which:-

Fig 1 is a side view of part of the apparatus of the present invention;

Fig 2 is a plan view of said apparatus; and

Fig 3 is a side view of the apparatus of the present invention secured to a gate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to Fig 3, a gate 2 of known type is rigidly secured at one end to a support standard 3 which is mounted upon pivot post 4 which is mounted in upper and lower bearings 5 (only the lower bearing is visible). The standard 3 and pivot post 4 are mutually parallel, and also parallel to a main support post 6 which replaces a conventional gatepost. An upper housing 7 is mounted on top of the post 6. The lower end of the post 6 is mounted on a baseplate 8 which is bolted or otherwise secured to the ground or other supporting surface.

The other end of the gate 2 is fitted with a conventional drop-latch 9, comprising a bar pivoted at one end to the gate and arranged to project outwards in place of the gate. The latch 9 is arranged to engage a notch formed in a projection 10 secured to the gatepost 11. The latch 9 is arranged so that to secure the gate 2 in the closed position shown in Fig 3, the latch 9 may be raised to lift it clear of projection 10, and allow the gate to swing freely on the bearings 5. A further post (not shown) is secured beside the post 6, parallel to the post 6 but spaced apart from it by a distance equal to the length of the gate 2. Said further post is provided with a projection the same as projection 10, so that the latch 9 can be engaged with said further projection to secure the gate in the open position.

Referring to Figs 1 and 2. the pivot position 4' comprises an inner post 4' which is journalled in the bearings 5, and an outer sleeve 12 which can slide up and down the inner post 4' and to which the standard 3 is secured by means of brackets 13. The outer sleeve 12 is also free to rotate about the inner post 4'.

The upper end of the standard 3 carries an arm 14, upon the upper end of which a cam follower 15 is mounted.

The cam follower 15 engages a cam track 16 which defines a part circular path and is substantially U-shaped when viewed in elevation. The cam track 16 has a central lower portion 17 and a raised portion 18, 18' at each end of the lower portion 17.

Since the whole weight of the gate 2, standard 3 and sleeve 12 rest on the cam follower 15, it tends to remain stationary in the central lower portion 17 under its own load.

The cam track 16 is rigidly secured to a toothed pulley 19 the circumference of which is formed with regularly-spaced teeth (not shown) which engage a drive-chain 21. The pulley 19 is concentric with the pivot post 4.

The drive-chain 21 extends around the pulley 19 and around a drive-pulley 22 which is rotatable in either direction by an electric motor (not shown). The diameters of the pulleys 19 and 22 are selected to achieve the desired speed of rotation of the pulley 19.

The upper surface of the toothed pulley 19 carries two spaced stops 23, 24 which project upwards from said surface. One stop 23 is located at one end of the cam track 16; the other stop 24 is located such that when the cam track is centred and the gate is closed, as shown in Figs 1 and 2, the stop 24 contacts an "off" switch 25.

The "off" switch 25 is connected to the electric motor via a reversing switch (not shown) so that once the "off switch 25 has been triggered by either stop 23 or stop 24. the electric motor is reversed when it is restarted. Thus, every time the electric motor is started, it drives in one direction, rotating the toothed pulley 19 in the same direction, until one of the stops 23, 24, contacts switch 25, stopping the electric motor. When the electric motor is restarted, it drives in the opposite direction, rotating the pulley 19 in said opposite direction, until the other stop 23, 24, contacts switch 25. The components 15 - 25 inclusive are contained within the housing 7.

The above-described apparatus is used as follows: the gate 2 is latched to the post 11 by engagement of the drop-latch 9 with the projection 10. In this position, the gate is closed, and the cam-follower 15 rests on the lower central portion 17 of the cam track 16 with the stop 24 in contact with switch 25.

To open the gate, the user starts the electric motor (which may be battery or mains powered) by means of a known remote-control device. The electric motor rotates the toothed pulley 19 in direction A (Fig.2). However, die cam follower 15, standard 3, sleeve 12 and gate 2 have sufficient inertia that they remain in the position of Fig 2, with the cam track 16 moving underneath the cam follower 15. The movement of the pulley 19 ceases when the stop 23 contacts the switch 25 and switches the motor off. At this point, the cam follower 15 engages the raised portion 18 of the cam track 16, so that the cam follower 15, arm 14, sleeve 12, standard 3 and gate 2 all are raised vertically in the direction of arrow C, so that the latch 9 is disengaged from the projection 10. Once the latch is disengaged, the gate 2 is free to swing under gravity, and the cam follower 15 rolls down the cam track 16, swinging the gate 2 to the fully open position. The gate may be allowed to rest in this position secured by the fact that the cam follower 15 is now at the lowest point of the cam track, or the gate 2 may be secured in the open position by a second post carrying a projection like projection 10, and engaging the latch 9 in the same manner.

To close the gate again, the electric motor is activated once more to rotate the toothed pulley 19 and the cam track 16 in the direction of arrow B, so that the cam track 16 moves beneath the cam follower 15 and raises the cam follower 15 vertically as the follower comes into engagement with the portion 18' of the cam track. The gate latch is disengaged from the latch as the gate is raised. Rotation of the pulley 19 ceases when the stop 24 contacts the switch 25, and the cam follower 15 rolls under gravity down the cam track to the lowest point 17, swinging the gate 2 back to the closed position in which the latch 9 engages the projection 10. The invention has been described above with the cam follower 15 connected to the gate 2. However, as an alternative, the cam track 16 and parts therewith could be connected to the gate instead of the cam follower 15. In this case the cam track is inverted with the end portions 18, 18' being lower than the central portion 17.

Claims

WHAT I CLAIM IS:

1. Apparatus for opening and closing a gate, including an elongate member arranged to support one end of a gate, as hereinbefore defined, such that said gate can pivot between an open position and a closed position, characterised by a cam follower and a co-acting cam track, formed on a body, one of the cam follower and the cam track being connected to the elongate member and the other of the cam follower and the cam track being connected to the gate, the cam track and the cam follower being shaped such that as the cam follower is moved along the cam track in either direction from a central region of die cam track, the cam follower and said body are moved apart.

2. Apparatus as claimed in claim 1 characterised in that the cam follower is free to roll along the cam track under gravity.

3. Apparatus as claimed in claim 1 or 2 characterised in that the one of the cam follower and the cam track which is connected to an elongate member is rotatable relative to said elongate member about the elongate axis thereof.

4. Apparatus as claimed in claim 3 in which the relative rotation is by means of an electric motor.

5. Apparatus as claimed in claims 3 or 4, characterised by the relative rotation being remotely controlled.

6. Apparatus as claimed in any of claims 1 to 5 characterised in that said cam track is part circular.

7. Apparatus as claimed in any of claims 1 to 6 characterised in that the cam follower is above and rests on the cam track, and the cam track provides two raised portions one on each side of die said central region which is lower.

8. Apparatus as claimed in any of claims 1 to 6 characterised in that the cam follower is below and supports die cam track, and die cam track provides two lower portions one on each side of said central region which is higher.

9. Apparatus as claimed in any of claims 1 to 8 characterised in mat the cam track is of part- circular form.

10. Apparatus as claimed in claim 3 characterised in that said relative rotation is terminated by a pair of stop means, representative of the gate open and the gate closed positions respectively.

11. Apparatus as claimed in claim 10 in which stop means includes an electrical switch.

12. Apparatus for opening and closing a gate connected and arranged and adapted to operate substantially as described herein and as shown in die accompanying drawings.

13. A gate as hereinbefore defined fitted with apparatus as claimed in any of claims 1 to 12.

14. A gate according to claim 13 fitted widi a drop latch adapted to be disengaged when d e gate is raised.

15. A gate as hereinbefore defined constructed and arranged and adopted to operate substantially as described herein and as shown in die accompanying drawings.