GB2345087A

GB2345087A - Drive mechanisms

Info

Publication number: GB2345087A
Application number: GB9924486A
Authority: GB
Inventors: Poi-Heong Tan
Original assignee: WHEELS ELECTRONICS MANUFACTURI
Current assignee: WHEELS ELECTRONICS MANUFACTURI
Priority date: 1998-10-19
Filing date: 1999-10-15
Publication date: 2000-06-28
Anticipated expiration: 2019-10-15
Also published as: GB9822835D0; GB2345087B; GB9924486D0

Abstract

A mechanism (1) for opening and closing doors or gates comprises an input shaft connected to a motor, an output shaft (5) connected to the door or gate and a linking assembly. The linking assembly connects the input shaft, carrying worm (6), to the output shaft (5) to transmit movement. The linking assembly includes a selectively operable coupling, preferably a clutch, which has a replaceable friction regulator. Preferably the friction regulator is a replaceable component such as a flat washer or a curved spring plate (12, 20). In an engaged state the coupling transmits movement from the input shaft to the output shaft. The linking assembly also includes an adjustment means (18) for varying the coupling engaging force. The force required to manually override the coupling and open the door is established by varying or setting the adjustment means which are readily accessible.

Description

IMPROVEMENTS IN DRIVE MECHANISMS The present invention relates to drive mechanisms in particular those for opening and closing doors and gates.

Mechanisms for opening and closing doors and gates are known. A typical known mechanism uses an electrically-powered motor to mobilise a gear mechanism to swing a gate. A general problem with this mechanism is that it is difficult to adjust the mechanism to optimum tension. Usually the whole mechanism is embedded below ground and this poses problems when it is necessary to operate the gate manually or repair or adjust the mechanism. In particular this positioning of the mechanism means that it is necessary to remove the mechanism from the ground whenever it is necessary to adjust the operating tension.

GB-A-2,264,534 describes a drive mechanism for powered opening and closing of a gate. Such a mechanism may be overridden when the gate is operated manually.

However, disadvantageously, since an essentially non-slip gear mechanism similar to other known mechanisms is used, repeated manual overriding of such a mechanism will soon result in degenerative deterioration of grooved component parts. This will lead to premature failure of the mechanism unless, inconveniently, the operating tension is reduced before manual operation and increased thereafter. Furthermore, the cost of replacing the grooved component parts is not insignificant since these parts are specific to the mechanism.

A general object of the invention is to provide an improved form of drive mechanism which solves the aforementioned problems. It is also an object to provide means by which the operating tension is easily adjustable and it is a particular object to provide means by which the operating tension is generally adjustable from the top. This can be done by the use of an Allen key or some other simple screwing device. It is also a particular object of the invention to provide a mechanism which can withstand repeated manual overriding without detrimental wearing of mechanism-specific component parts.

It is also a particular object of the invention to provide a mechanism which can be overridden without the need for adjustment immediately before and/or after manual use of the door or gate.

According to the invention there is provided a mechanism for opening and closing doors and gates, said mechanism comprising input means, output means and linking means, said input means being connectable to a motor, said output means being connectable to a door or gate for opening and/or closing thereof and said linking means connecting said input means to said output means to allow movement to be transmitted therebetween, said linking means including selectively operable coupling means having a replaceable friction regulator, the coupling means being adapted in an engaged state to transmit driving movement from the input to the output means and said linking means also including adjustment means for varying the coupling means engaging force so that the force required to manually override the coupling means and open the door is established by varying or setting the adjustment means, said adjustment means being readily accessible when the mechanism is in its operating environment.

If a mechanism constructed in accordance with the invention is persistently manually overridden the friction regulator may wear. Advantageously, with the friction regulator as a conventional non-mechanism-specific component, such as a washer or a spring plate, an inexpensive replacement may be fitted to maintain the mechanism in working order.

Preferably the friction regulator has a uniform or regular areal contact friction surface so that any wear is evenly distributed rather than being unevenly borne by discrete projections or the like.

Preferably, the coupling means is a clutch comprising at least one friction surface, a pressure plate and clutch engaging means which can comprise the friction regulator.

In a preferred embodiment the linking means include a drive pin which connects the output shaft to the clutch. The drive pin may be located in a transverse bore, e. g. a radial bore, of the output shaft and may be moveable axially of the output shaft to vary the engaging force applied to the components of the clutch.

The mechanism can have an axial bore at its top which connects with the transverse bore. The shaft can protrude beyond a cover plate of the mechanism so that the clutch engaging means can be adjusted using a set screw or the like.

In another preferred embodiment a second drive pin is provided which is located in a second transverse bore. The mechanism may have the first and second drive pins positioned either side of the pressure plate with two friction surfaces, each interposed between each pin and the pressure plate. The clutch engaging means incorporating the friction regulator may be positioned between each pin and friction surface and a friction coupling may be positioned between each clutch engaging means and friction surface, each friction coupling being coupled to each drive pin.

Further preferred embodiments may include a gear mechanism in the linking means where the pressure plate is a gear wheel. This gear wheel can be a helical gear which may be driven by a worm gear powered by a motor or through other gear means.

A normal flat washer acting as the friction regulator may be interposed between the or each drive pin and the or each friction surface. The or each drive pin may be a tension rod which at least partially act as the clutch engaging means.

In a preferred embodiment the clutch engaging means are spring means taking the form of a curved spring plate which acts as the friction regulator and flattens under pressure to provide an opposing force thereby increasing the friction provided.

An embodiment may have both at least one tension rod and at least one curved spring plate.

An embodiment of the invention will now be described in more detail hereinafter, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is a longitudinal section through a mechanism according to the invention; Figure 2 is an exploded view of the components of the mechanism in Figure I shown together with the armature of a motor for the mechanism ; Figure 3 shows a plate to which the housing shown in Figures 1 and 2 is secured ; and Figure 4 shows the plate and housing together.

Figures I and 2 show a drive mechanism 1 composed of a housing part 2, the top of which takes the form of a plate. Holes 3 in the plate are provided to secure the housing part to the bottom of a larger plate 4 (Figures 3 and 4) which has a hole 21 designed to fit a bushing or bearing 22 which holds the protruding part of the output shaft 5. An'o'-ring (not shown) is used to prevent water from leaking into the mechanism through this hole 21. The plate 4 when fitted for use would be at ground level or above ground level.

The mechanism comprises an input shaft, an output shaft 5 and a linking assembly. The input shaft which carries a worm gear 6 is made to rotate by the use of a gear or combination of gears driven by a motor 7, usually an electrically-powered motor.

The end of the input shaft remote from the motor is supported by a bushing or bearing 8 in the housing 2.

The worm gear 6 on the input shaft serves to rotate a helical gear 9 mounted onto the main output shaft 5. This output shaft 5 is either connecte to a door or gate for which it serves as the axis of rotation or connected to two or more gears to drive a means which serve as the axis of rotation for a door or gate.

The linking assembly comprises a clutch system which is housed inside the housing part 2 along with the worm gear 6 and helical gear 9. The clutch system allows manual operation of the door or gate by slipping and is mounted on the axis of the output shaft 5. It comprises the horizontal helical gear 9 which is surrounded above and below by a friction disc 10, a friction coupling 11, a friction regulator in the form of a curved spring washer 12,20 and a drive pin 13,19. The friction discs 10 are attached to the couplings 11. The curved spring washers 12, 20 urge the friction discs 10 and couplings 11 towards the helical gear and the engaging force provided by the spring washers 12,20 in co-operation with the friction discs 10 establishes the force required to override the clutch when opening or closing the door or gate manually. Properties of any one or more of the components of the mechanism may contribute to the establishing of this force in other embodiments of the invention.

The drive pins 13,19 run through upper 14 and lower 15 horizontal bores in the output shaft 5 and engage the output shaft, connecting the shaft to the clutch through the friction coupling I 1 to enable driving movement to be transmitted from the input shaft to the output shaft 5. The lower end of the output shaft rests on a bearing or bushing 16 beneath the lower drive pin 13 of the clutch assembly. The upper horizontal bore 14 is configured to allow movement of the upper drive pin 19 axially of the output shaft 5.

Movement of this pin in this direction allows the engaging force of the curved spring washer to be varied.

A vertical bore 17 in the top of the output shaft 5 is provided to accept a screw 18. This vertical bore 17 joins the upper horizontal bore 14 of the main shaft 5 which serves to hold the upper drive pin 19. Screwing the screw 18 so that it moves down to press on the upper drive pin 19 causes this pin to move downwards to press on the top curved spring washer 20. The wide configuration of this bore allows the pin to move in this direction. The force on the top curved spring washer 20 causes the curved spring washers 12,20 to exert a greater force on the friction couplings 11 and discs 10 which, in turn, increases the engaging force. This engaging force establishes the point at which the clutch means will slip when the door or gate is manually opened.

An alternative embodiment has the friction discs attached to the helical gear rather than the couplings.

In another embodiment normal flat washers are used instead of curved spring washers as the friction regulator. In a further embodiment tension rods are used instead of drive pins. Curved spring washers and tension rods are used together in yet another embodiment.

All described embodiments of the invention possess a replaceable friction regulator which is a non-mechanism-specific component (i. e. it is not a component machined to be particular to the mechanism but rather a standard propriety item). The friction regulator can be inexpensively replaced, reducing maintenance costs of a mechanism constructed in accordance with the invention. Furthermore, the friction regulator in the form of one or more curved spring washers serves to compensate for any potential decrease in the engaging force caused by wear of the other components. In other words any loss in pressure caused by wearing of other components is compensated for by the curved spring washers.

Claims

CLAIMS 1. A mechanism for opening and closing doors and gates, said mechanism comprising input means, output means including an output shaft and linking means, said input means being connectable to a motor, said output means being connectable to a door or gate for opening and/or closing thereof and said linking means connecting said input means to said output means to allow movement to be transmitted therebetween, said linking means including selectively operable coupling means having a replaceable friction regulator, the coupling means being adapted in an engaged state to transmit driving movement from the input to the output means and said linking means also including adjustment means for varying the coupling means engaging force so that the force required to manually override the coupling means and open the door is established by varying or setting the adjustment means, said adjustment means being readily accessible when the mechanism is in its operating environment.
2. A mechanism according to claim 1, wherein the friction regulator is a nonmechanism-specificcomponent.
3. A mechanism according to claim 1 or 2, wherein the coupling means is a clutch having as components a pressure plate, at least one friction surface and clutch engaging means which comprise the friction regulator.
4. A mechanism according to claim 3, wherein the friction regulator is interposed between the pressure plate and a part of the adjustment means.
5. A mechanism according to claims 3 or 4, wherein the clutch engaging means comprise spring means.
6. A mechanism according to any one of claims I to 5, wherein the friction regulator is a flat washer.
7. A mechanism according to claim 5, wherein the friction regulator is a curved spring plate which constitutes at least partially the spring means and which flattens under pressure to provide an opposing force, thereby increasing the friction on the friction surface and compensating for any loss in pressure caused by wear of other components.
8. A mechanism according to any one of claims 3 to 7, wherein the linking means comprises a drive pin which is arranged to engage said output shaft and to connect said shaft to clutch.
9. A mechanism according to any one of claims 3 to 8, wherein the linking means is mounted on the output shaft and comprises a drive pin located in a transverse bore in the shaft and adapted to engage a component of the clutch.
10. A mechanism according to claim 9, wherein the position of the drive pin is movable axially of the output shaft to vary the engaging force applied to the components of the clutch.
11. A mechanism according to claim 10, wherein the output shaft has an axial bore at its top which connects with the radial bore.
12. A mechanism according to claim 11, wherein the shaft protrudes beyond a cover plate of the mechanism so that the clutch system can be adjusted by using an Allen key, set screw or screwing device engagable with the axial bore.
13. A mechanism according to any one of claims 8 to 12, wherein the linking means comprises a second drive pin which is arranged to engage said output shaft and to connect said shaft to the clutch.
14. A mechanism according to claim 13, wherein said second drive pin is located in a second transverse bore in the output shaft.
15. A mechanism according to claim 14, wherein the first and second drive pins are positioned on either side of the pressure plate and the at least one friction surface takes the form of two friction surfaces, each interposed between one of the pins and the pressure plate.
16. A mechanism according to any one of claims 8 to 15, wherein the clutch engaging means further comprise another friction regulator and each friction regulator is interposed between the or each drive pin and the or each friction surface.
17. A mechanism according to any one of claims 8 to 16, wherein a friction coupling is positioned between the or each friction regulator and the or each friction surface and is coupled to the or each drive pin.
18. A mechanism according to any one of claims 1 to 17, wherein the linking means includes a gear mechanism.
19. A mechanism according to claim 18, wherein the gear mechanism is enclosed in the housing along with the clutch means.
20. A mechanism according to claim 18 or 19, wherein the pressure plate is a gear wheel.
21. A mechanism according to any one of claims 18,19 or 20, wherein the gear wheel is a helical gear.
22. A mechanism according to any one of claims 18,19,20 or 21, wherein the gear wheel is driven by a worm gear.
23. A mechanism according to claim 22, wherein the worm gear is powered by a motor, either directly, or through another gear or other means.
24. A mechanism according to any one of claims 8 to 23, wherein the or each drive pin takes the form of a tension rod which constitutes at least partially the clutch engaging means.
25. A mechanism substantially as described herein with reference to the accompanying drawings.