GB2085960A - Opening and closing gates by a motor-driven ground-engaging wheel - Google Patents

Abstract

A gate operator includes a motor driven ground wheel 16 which is biassed into contact with the ground or floor. The motor 17 is secured to a part of the gate 3, 4 to be moved, and in the case of a hinged gate this is preferably a part most remote from the hinges, so as to secure the most mechanical advantage. The drive motor may thus be a small, low voltage D.C. motor, and is mounted on the gate by means of channel member 11 having rails 12 cooperating with rollers 10 on a carrier 1 fixed to the gate. <IMAGE>

Description

SPECIFICATION Automatic gate operator This invention relates to a power-operated device or operator for opening and shutting gates or doors. Where the term gate is used in the specification it is to be understood as including also a door.

Existing automatic gate operators for swing type gates actuate at or close to the hinge or pivot and so require comparatively large electric or other motors and power to exert the necessary force to move the gate; the equipment is large and unsightly, is costly and is complex enough to require specillist installation.

An object of the invention is to privide a device which is relatively simple and inexpensive and which can eliminate the need for specillist installation.

According to one aspect of the invention a gate operator comprises a motor-driven ground wheel and is arranged to be secured to a part of the gate to be moved relative to the ground or floor so as to drive the gate open or closed, and so connected to the gate that it can move vertically with respect thereto, the wheel being biassed into contact with the ground or floor. Vertical movement of the wheel may be achieved in various ways, for example the operator may be carried by a single or double pivoted arm, but preferably is arranged for attachment to the gate by means of a sliding connection and the necessary bias may be provided by the weight of the operator itself.

As applied to hinged gates, the operator is preferably arranged as far from the hinge as possible so as to give the most favourable machanical advantage, but the invention is also applicable to operators for sliding doors or gates, in which case the positioning is not important from this point of view. The motor is preferably a low voltage motor and may be powered by a battery or from the output of a transformer. Since the drive needs to be reversible a D.C. motor is to be preferred.

In order to permit a gate to which the operator is attached to be opened manually, some means for allowing the gate to be opened independently of the mechanical drive may be incorporated. This may take the form of means for manually lifting the drive wheel from the ground or by providing a slipping clutch and the invention includes a novel form of such clutch, which may be incorporated in the drive wheel itself. The invention also includes a novel form of limit switch.

Other features of the invention will appear from the following description of one form thereof with reference to the accompanying drawings in which: Figure 1 is an exploded perspective view of part of an iron gate, a mounting plate and a drive unit, Figure 2 is a sectional view of a slipping clutch, Figure 3 is a scrap view of a limit switch arrangement, and Figure 4 is a circuit diagram of a manual switching control circuit for opening and shutting a gate to which the operator is attached.

In Fig. 1 a base plate comprises essentially a channel shaped member 1 to the rear of which is welded a pair of channel shaped mounting bars 2. In this case the base plate is intended for mounting on an iron gate, two of the vertical members of which are shown at 3 and 4. Each bracket is completed by a channel shaped clamp bar 5, shown spaced away to the rear so that the construction may be clearly seen. Each clamp bar 5 has welded to it a stud 6 arranged to project through a hole in the base plate 1 and secured by a nut 7 which, when tightened, draws the clamp bar 5 towards the corresponding bar 2 so as to clamp the base plate 1 firmly to the members 3 and 4.Access to the shanks of the studs 6 is prevented by tabs 9 of a stirrup member located in the channel of the clamp bar 5 by the stud 6 which passes through it, and the tabs 9 also locate the base plate 1 with respect to the gate members 3 and 4.

In the event that the base plate is to be attached to a wooden gate, wood screws are used through suitable holes in the base plate, but in either case the heads of the securing elements are housed within the channel shaped base plate 1.

The base plate 1 has on its inner sides a series of rollers 10 and the drive unit of the invention is arranged to slide up and down on these rollers. This is achieved by constructing the drive unit as an enclosed gear housing 8 to which a drive motor 1 7 and a ground wheel 1 6 are attached, the housing 8 thus protecting the gears and being secured to a channel member 11 within which is fixed a double rail member 12. The rollers 10 are engaged with suitable clearance by the surfaces of the rail member 1 2 and the channel member 11.The housing 8 which may be of sheet metal or may be a die-casting is attached to the channel member 11 by side plates 1 3 which pass through apertures in the member 11 and are secured in position by a headed pin 1 4 which extends transversely through suitable holes in the sides of the member 11 and in the side plates 1 3. The pin 14 may be locked in position by means of a padlock (not shown) the hasp of which can pass through the hole 1 5. The pin 14 also serves to lock the unit to the base plate 1 since it is trapped in the cut-away portions of the sides of the base plate. Thus, the channel member 11 has only a limited vertical movement, and in all positions covers the nuts 7 or other fastenings. The security of the whole unit is thus obtained by a single padlock.

As will be seen, the unit has a ground wheel 1 6 projecting from below the housing 8 and this is driven through a suitable speedreducing drive (not shown) which may be a gear train, by a small electric motor 1 7. Limit switches are provided within the housing 8 and operable by a feeler 1 8 which strikes a suitable projection 1 9 at each terminal position of the gate, the arrangement being shown in detail in Fig. 3. The feeler 18 is attached to a pivoted arm 1 8a which is held in a neutral position by a tension spring 20.

When the feeler strikes one of the projections 1 9 the spring 20 is deflected and contacts the operating button of one of the two microswitches 21, thus cutting off the power supply to the motor 17. The operation of this is clear form the circuit diagram in Fig. 4. The power is applied as a D.C. potential to the terminals 22 and thence through a double pole change-over switch 23 to the motor 1 7.

In each position of the switch 23 one polarity is applied directly to the motor and the other is applied through one of the micro-switches 21. The motor is then energised to drive the gate in such a direction that the projection 1 9 appropriate to that micro-switch is engaged, so that the gate is driven to its terminal position and then stops as the power is disconnected. For movement in the opposite direction the switch 23 is reversed when power is supplied to the motor with the opposite polarity through the other microswitch.

The switch 22 may be mounted remotely, and since only a low voltage supply is involved the installation may be carried out by relatively unskilled persons. It will be appreciated that the operator also lends itself to operation by means of radio or other indirect signals such as infra-red, in which case the switch 23 can be driven by suitable responders.

The terrain over which the operator can operate can be very uneven or steeply sloping since the movement of the unit in the vertical direction is limited only by the length of the members 1 and 11.

In some cases when the switch 23 is located in a position not accessible to all users of the gate to which the operator is fitted, it may be desirable to permit the gate to be operated manually, and to this end, a slipping clutch may be incorporated in the gear train or other speed reducing drive. Such a clutch is shown in Fig. 2 and consists essentially of a central drive element 24 having a marginal recess with a ramp surface 25. The element 24 is arranged within a concentric ring 26.

Between the ramp surface 25 and the ring 26 is a cylinder 27 urged into the position shown by a piston 28 and spring 29 located in a bore in the element 24. The parts 24 and 26 are conveniently made of a high grade alu minium alloy and the cylinder 27 can be made of the material known under the Registered Trade Mark 'Tufnol'. With these materials an appropriate amount of slip is permitted when the clutch is incorporated into the hub of the wheel 1 6 to permit the gate to be moved manually against the action of the motor 1 7. In such conditions the motor will operate to reclose the gate after it has been opened manually. The friction in the speedreducing drive will normally be sufficient to retain the gate in the terminal position to which it has been driven. In an alternative arrangement (not shown) a hand lever may be provided for operating the gate by hand which, when operated, lifts the ground wheel or the whole of the unit of which the wheel forms part so that the wheel is clear of the ground. In this case the motor and the wheel will run free while the lever is operated and again the gate will return to its original position after the lever is released.

Although the clutch of Fig. 2 is shown as having only one friction cylinder, it will be appreciated that a number of these may be provided if desired by machining the element 24 to create more ramp surfaces.

Claims (11)

1. A gate operator including a motor driven ground wheel and arranged to be secured to a part of the gate to be moved relative to the ground or floor so as to drive the gate open or closed, and so arranged that the wheel can move vertically with respect thereto, the wheel being biassed into contact with the ground or floor.

2. A gate operator according to claim 1, wherein the whole of the operator is movable to provide vertical movement for the wheel.

3. A gate operator according to claim 2, wherein the operator is mounted on the gate by means of one or more radius arms.

4. A gate operator according to claim 1, wherein the operator is slidable vertically with respect to the gate.

5. A gate operator according to any one of the preceding claims, wherein the ground wheel, an electric driving motor and a speed reduction drive are constructed as a unit and the bias applied to the ground wheel is that due to the weight of the unit.

6. A gate operator according to any one of the preceding claims, wherein the ground wheel is driven by an electric motor through a speed reduction drive and the combined friction in the motor and drive is sufficient to maintain the position of the gate when the motor is de-energised.

7. A gate operator according to any one of the preceding claims wherein the drive to the ground wheel takes place through a slipping clutch to enable the gate to be moved manu ally.

8. A gate operator according to claim 7, wherein the clutch is incorporated into the hub of the ground wheel.

9. A gate operator according to claim 1 and any one of claims 4 to 8, wherein the sliding motion is by means of interengaging channels of a mounting bracket and a drive unit support, with optional interposed antifriction elements.

10. A gate operator according to claim 9, wherein removal of the drive unit support from the mounting bracket is prevented by a locking device.

11. A gate operator according to claim 10, wherein the locking device is in the form of a pin and slot type connection with the pin being lockable in one of the components.

1 2. A gate operator according to claim 9 or claim 10, wherein the locking device also serves to secure a cover for the drive mechanism.