GB2576833A

GB2576833A - Safety mechanism for a door or gate

Info

Publication number: GB2576833A
Application number: GB1914179.5A
Authority: GB
Inventors: Clewer-Evans Morgan
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-01
Filing date: 2019-10-01
Publication date: 2020-03-04
Anticipated expiration: 2039-10-01
Also published as: GB201914179D0; GB2576833B

Abstract

The safety mechanism 100 for a door closer comprises a housing 10 for mounting to a barrier 8, a carriage to move along the housing, a resiliently biased cam 2 rotatably mounted to the carriage, an arm 4 with a first end connected to the cam at a position which is offset from the rotational axis such that, when rotational movement of the barrier exceeds a threshold, the cam engages with the housing and slows further motion of the carriage, and the second end of the arm is connected to a structure 40 defining the opening. The arm may comprise a damper and a moveable stopper may be arranged to limit the travel of the carriage within the housing. A series of holes may be distributed along the housing to receive the moveable stopper. Also claimed is an opening arrangement comprising a barrier hinge and the safety mechanism 100.

Description

Safety mechanism for a door or gate

Field of the Invention

The present invention concerns a safety mechanism for a barrier such as a gate or a door. More particularly, but not exclusively, this invention concerns a safety mechanism for preventing a barrier from slamming open or shut.

Background of the Invention

Barriers, such as doors and gates, may be caused to move by incident airflow, such as wind. This is particularly likely for barriers that are situated at least partially outside. It is a problem that airflow, such as wind gusts, may act against such barriers, sometimes unpredictably, with the possible effect of accelerating the barriers to high speed. Such fast moving barriers can be a hazard to those in the vicinity, and/or such fast movement may cause the barrier to slam open or shut, which may cause damage to the barrier or to the structure to which the barrier is mounted.

The present invention seeks to mitigate the above-mentioned problems. Alternatively or additionally, the present invention seeks to provide an improved safety mechanism for a barrier such as a door or gate.

Summary of the Invention

The present invention provides a safety mechanism for a barrier, such as a gate or a door, hinge mounted to a structure defining an opening, the safety mechanism comprising: a housing arranged to be mounted on the barrier; a carriage arranged to move along the housing; a cam rotatably mounted to the carriage; a resilient bias arranged to bias the cam in an orientation in which the carriage can move freely along the housing; an arm having a first end connected to the cam and a second end connectable to the structure such that, in use, rotational movement of the barrier relative to the structure causes the arm to translate the carriage along the housing; and wherein the arm is mounted to the cam at a position which is offset from the rotational axis of the cam such that, when rotational movement of the barrier exceeds a

-2threshold rate, the arm rotates the cam against the bias causing the cam to engage with the housing and thereby slow further motion of the carriage relative to the housing.

The safety mechanism according to the present invention may improve safety by limiting the rate at which the barrier can move. Preferably the threshold rate is set such that the barrier is unable to reach a potentially dangerous or damaging speed. The threshold rate may be a threshold speed and/or threshold acceleration. It will be appreciated that an appropriate threshold rate may depend on several factors, for example, the particular situation in which the barrier is used, the type of the barrier, the size of the barrier and/or the weight of the barrier. The present invention may have particular application for external barriers, such as sheeted gates (also referred to as sheeted doors), which comprise a solid door leaf.

Engagement of the cam with the housing may prevent further motion of the carriage relative to the housing. The cam may engage with the housing by jamming against the housing. Further movement of the carriage relative to the housing may be slowed or prevented by frictional engagement of the cam with the housing.

The arm may comprise a damper for damping movement of the first end of the arm relative to the second end of the arm. The damper may thereby, in use, damp the rate at which the barrier is caused to slow (i.e. decelerate) upon engagement of the cam with the housing. The damper may help prevent the barrier from coming to an abrupt stop upon engagement with the cam and the housing. The damper may be a shock absorber. Abruptly stopping the barrier may cause increased levels of stress on the barrier and the structure to which it is mounted.

The safety mechanism may comprise a stopper for limiting the travel of the carriage within the housing. For example, the stopper may be used for preventing the barrier from reaching a fully open and/or a fully closed position. The stopper may be movable between a plurality of different stopping positions. The stopper may be movable between a plurality of discrete stopping positions. A plurality of stoppers may be provided to limit the travel of the carriage in both the open and close directions.

The housing may comprise a series of holes arranged to receive the removable stopper therein. Each hole may define a stopping position. The holes may be distributed along the housing. The holes may be distributed along a line of motion of the carriage. In an embodiment, the housing comprises opposing surfaces, each opposing surface having a series of holes. The surfaces may be arranged to receive a

- 3 pin that extends through two opposing holes. The pin may act as the stopper to limit movement of the carriage.

The cam may comprise an engagement surface for engaging the housing. The engagement surface may comprise a high friction surface. For example, the engagement surface may comprise a series of projections. The projections may be in the form of knurls, grooves, and/or teeth. The grooves may be oriented to resist sliding of the cam along the housing. In another example, the engagement surface may comprise a rubber material or the like. The projections and/or rubber material may help increase the friction between the cam and the housing. This may help reduce slipping of the cam along the housing. This may help provide faster and/or more reliable slowing of the barrier.

The projections and/or rubber material may be provided around the extent of the cam. In embodiments, the projections and/or rubber material may only be on segments of the extent of the cam. Those segments may be the portions of the cam that come into contact with the housing upon rotation of the cam.

The surface of the housing with which the cam engages may be arranged so as to increase the friction between the housing and the cam. For example, the surface may comprise a rubber material. The engagement surface may comprise a series of projections. For example, the projections may be in the form of knurls, grooves, and/or teeth.

The safety mechanism may be arranged such that, when rotational movement of the barrier exceeds the threshold rate, two opposing ends of the cam engage with the housing. The housing may provide opposing surfaces with which the opposing ends of the cam engage. By providing a cam with two opposing ends arranged to engage with two opposing surfaces of the housing, the forces on the cam may be more balanced about the rotational axis of the cam, and the stopping power of the safety mechanism may be similar in both directions of movement of the barrier.

The cam may be elliptically shaped. The cam may be arranged so that the major axis (the widest diameter) of the cam is parallel to the direction of movement of the carriage relative to the housing when the carriage moves freely. The cam may be an elliptical cylinder. The thickness of the cylinder may vary, but preferably the thickness does not exceed the diameter of major axis of elliptical surface. The cam may be provided with the aforementioned high friction surface at regions proximate each vertex of the ellipse.

-4The housing may comprise one or more tracks in which the carriage is arranged to slide. One or more of the tracks may define a surface of the housing. The carriage may comprise a spindle on which the cam is mounted. The carriage may comprise a second spindle. The resilient bias may be mounted to the second spindle.

Each track may comprise a slot in which the spindle(s) moves.

The carriage may comprise a bearing, preferably a pair of bearings, arranged to engage the one or more tracks. The bearings may be mounted at opposing ends of the spindle. The bearings may reduce the friction associated with movement of the carriage relative to the housing. The bearings may be circular. The bearings may have a greater diameter than the minor axis of the cam.

In order for the cam to be rotated by the arm against the bias, there may need to be a certain amount of force (e.g. friction) opposing movement of the carriage relative to the housing and/or opposing rotational movement of the arm about its second end. The arm may be pivotally mounted to the cam.

The resilient bias may be mounted to the cam at or near the periphery of the cam. The resilient bias may be a spring, such as a coil spring or a leaf spring. The resilient bias may be an elastic chord (e.g. an elastic band).

The housing may provide an enclosure. The housing may enclose the carriage and the track. Enclosing the carriage and the track may help protect those moving parts from contamination and exposure to weather. The housing may comprise an opening, such as in the form of a slot, through which the arm extends. The housing may be formed of galvanised steel, although it will be appreciated other materials may be used that can withstand the environmental conditions the safety mechanism is to be exposed to.

The housing may comprise flanges arranged to lie flush with the side of the barrier, through which the housing may be bolted to the barrier. This may help ensure that the safety mechanism is securely mounted to the barrier.

The second end of the arm may be rotatably mounted to a mount. The mount may be arranged for mounting to the structure. The mount may, for example, include holes to received bolts for bolting the mount to the structure. The mount may be arranged for mounting to, for example, a fixed structure such as a gate post or a wall.

The present invention provides, according to a second aspect, an opening arrangement comprising: a barrier hinge mounted to a structure defining an opening, and a safety mechanism according to any preceding claim; wherein the housing is

- 5 mounted to the barrier and the second end of the arm is pivotally mounted to the structure such that rotational movement of the barrier relative to the structure causes the arm to translate the carriage along the housing. The barrier may be a door or a gate.

It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention. For example, the method of the invention may incorporate any of the features described with reference to the apparatus of the invention and vice versa.

Description of the Drawings

Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which:

Figure 1 shows a plan view of a safety mechanism according to a first embodiment of the invention mounted to a gate in a closed position;

Figure 2 shows a cross sectional side view of the safety mechanism;

Figure 3a shows a second plan view of the safety mechanism;

Figure 3b shows a side view of the safety mechanism;

Figure 4 shows a plan view of the safety mechanism with the gate in both an open position and the closed position; and

Figure 5 shows the safety mechanism according to a second embodiment of the invention.

Detailed Description

Figure 1 shows the safety mechanism 100 mounted on a barrier in the form of a gate 8. The safety mechanism 100 is located at or near the hinge 32 of the gate 8. The safety mechanism comprises a housing 10, the outline of which is shown in figure

1. Within the housing 10 there is provided a carriage comprising a cam 2. The cam 2 is pivotally mounted to the carriage and pivotally connected to a first arm 4. The cam 2 is elliptical. The arm 4 is pivotally connected at a first side of the elliptical cam 2 at a point along its major axis distal from the axis of rotation. The arm 4 is pivotally attached to the cam 2 via a fixing member comprising a shoulder bolt and a nut

- 6arranged to engage with the bolt. In alternative embodiments, the cam 2 is attached to the arm 4 with a permanent fixing means such as a weld.

The carriage comprises a first spindle 20a and a second spindle 20b. The centre of the cam 2 is mounted to the first spindle 20a. The first spindle 20a and the second spindle 20b are attached together at a fixed distance by a connecting piece (not shown). In this embodiment, the connecting piece is a sheet of metal. On a second side of the cam 2, opposite the first side where the arm 4 is connected, there is attached a resilient bias in the form of an elastic cord 6. The elastic cord 6 extends from the cam 2 and is attached to the second spindle 20b. The elastic cord 6 biases the cam in an orientation in which the major axis of the elliptical cam 2 is aligned with the longitudinal axis of the housing 10. In this orientation of the cam 2, the carriage can move freely along the housing 10.

The arm 4 has an L shape which firstly extends directly away from the housing 20 and then extends parallel to the longitudinal axis of the housing 10 towards a fixed structure 40 to which the gate 8 is rotatably mounted. The arm 4 comprises a damper 18 comprising a coiled spring. The arm 4 is mounted to the fixed structure 40 via a mount 26. The damper 18 reduces the rate at which the gate 8 decelerates when the cam 2 engages with the housing (as will be described in further detail below).

Figure 2 shows the safety mechanism as seen through a cross section of the housing 10. Only the second spindle 20b is visible with the first spindle 20a directly behind the second spindle 20b in view. The carriage further comprises bearings 22 attached at each end of the spindles 20a, 20b. The spindles 20a, 20b are received within two tracks 30. The tracks 30 each comprise a box section having a slot extending along the length thereof, the spindles 20a, 20b extend through the slot. The tracks 30 extends parallel to the longitudinal axis of the housing 10 such that the carriage can move along the housing 10 in the longitudinal direction of the housing

10.

The spindles 20a, 20b can also rotate freely within the tracks 30 such that the cam 2 can rotate with respect to the housing 10. The cam 2 can rotate between two orientations, indicated in Figure 1 by reference numerals 2’ and 2”, in which the cam 2 is engaged with lateral sides of the housing 10.

The housing comprises a generally rectangular outer casing. The tracks 30 are attached to a top side 10a and a bottom side 10b of the housing 10. In an alternative

- 7embodiment, the track 30 may be provided by the sides 10a, 10b of the housing 10.

The outer casing of the housing 10 further comprises an opening 36 in the form of a slot through which the arm 4 projects.

The housing 10 is mounted to the gate 8 via six L-shaped brackets 12 which are bolted to both the top side 10a and the bottom side 10b of the housing 10, respectively. The brackets are in turn bolted to the gate 8 through the perpendicular part of the L-shaped bracket. In an alternative embodiment, the safety mechanism 100 is attached to the gate using bolts arranged directly through the housing 10.

Figure 3a shows the safety mechanism 100 arranged on the gate 8 but with the upper side 10a of the housing visible. Also shown is three of the L-shaped brackets 12 distributed along the length of the housing 10. Figure 3b show a side view of the safety mechanism 10 with the slot 36 clearly visible. Figure 4 shows the safety mechanism 10 with the gate 8 in both an open and closed position. As can be seen, in the open position, the carriage with cam 2 has been moved to an opposite end of the housing 10 by the arm 4.

In use, when the gate 8 is pushed open by a user in the direction of arrow 200, the cam 2 and the arm 4 cooperate such that the carriage is pushed, via the cam 2, along the track 30 in the housing 10 in a direction away from the hinge 32. The resilient bias 6 acts to keep the major axis of the cam 2 substantially aligned with the direction of motion of the cam relative to the housing (i.e. parallel to the longitudinal axis of the housing). Provided that the force applied to the gate 8 does not cause the gate to travel in excess of a threshold speed or acceleration, the cam 4 travels along the housing 10 to the position A. When the gate 8 is closed, again without exceeding the threshold speed or acceleration, the cam 2 is caused to travel back along the track 30 to its starting position.

When the gate 8 is exposed to high forces, for example those caused by environmental conditions such as a gust of wind, the speed of the gate 8 and/or acceleration of the gate 8 may exceed the threshold, thereby causing the arm 4 to act against the biasing force of the resilient bias 6 to an extent that the cam 2 is caused to rotate into engagement with the lateral sides of the housing 10. When the gate 8 is moved in a closing direction, the arm 4 pulls the cam 2 such that the cam rotates to an orientation indicated by reference numeral 2’. When the gate 8 is moved in an opening direction, the arm 4 pushes the cam 2 such that the cam rotates to an orientation indicated by reference numeral 2”.

- 8The cam 2 comprises a series of grooves around its lateral extent in regions where the cam 2 comes into contact with the surface of the housing 10 when the cam 2 rotates. The grooves help lock / jam the two laterally projecting sides of the cam 2 against the surface of the housing 10, thereby slowing or stopping the movement of the carriage relative to the housing. In turn, the motion of the gate 8 is slowed or stopped. The damper 18 may allow the gate 8 to move slightly even with the cam 2 engaged with the housing 10 and jammed in position. The damper may thereby lessen the rate at which the gate 8 decelerates and may help prevent damage to the gate 8 and the safety mechanism 100.

Once movement of the door has slowed or stopped, the resilient bias 6 acts to realign the cam 2 with the longitudinal axis of the housing 10 such that movement of the door can continue. It may be that the gate 8 needs to be pulled or pushed slightly to disengage the cam 2 from the housing 10.

In a second embodiment of the safety mechanism 200, the housing 210 comprises a plurality of holes 211. The holes 211 are distributed along the upper and lower sides of the housing 210 as shown in Figure 5. The holes in the upper side face the holes in the lower side. The holes are arranged to receive a stopper in the form of a pin that can pass through the housing. The pin can be used to impede the movement of the carriage relative to the housing 210 so as to limit the range of motion of the gate 8, for example to hold the gate open at a certain angle. In embodiments, multiple pins may be provided to limit the motion of the gate in more than one direction.

Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein. Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.

Claims

1. A safety mechanism for a barrier, such as a gate or a door, hinge mounted to a structure defining an opening, the safety mechanism comprising:

a housing arranged to be mounted on the barrier;

a carriage arranged to move along the housing;

a cam rotatably mounted to the carriage;

a resilient bias arranged to bias the cam in an orientation in which the carriage can move freely along the housing;

an arm having a first end connected to the cam and a second end connectable to the structure such that, in use, rotational movement of the barrier relative to the structure causes the arm to translate the carriage along the housing; and wherein the arm is mounted to the cam at a position which is offset from the rotational axis of the cam such that, when rotational movement of the barrier exceeds a threshold rate, the arm rotates the cam against the bias causing the cam to engage with the housing and thereby slow further motion of the carriage relative to the housing.

2. A safety mechanism according to claim 1, wherein the arm comprises a damper arranged to damp movement of the first end of the arm relative to the second end of the arm.

3. A safety mechanism according to any preceding claim, further comprising a stopper arranged to limit the travel of the carriage within the housing, wherein the stopper is movable between a plurality of different stopping positions.

4. A safety mechanism according to claim 3, wherein the housing comprises a series of holes arranged to receive the movable stopper therein, the holes being distributed along the housing, each hole defining one of the stopping positions.

5. A safety mechanism according to any preceding claim, wherein the cam comprises an engagement surface for engaging the housing, the engagement surface comprising a series of projections.

6. A safety mechanism according to any preceding claim, wherein the housing comprises a surface with which the cam engages, the surface comprising a rubber material.

7. A safety mechanism according to any preceding claim, wherein the cam is elliptically shaped, wherein two opposing ends of the cam are arranged to engage with the housing when rotational movement of the barrier exceeds the threshold rate.

8. A safety mechanism according to any preceding claim, wherein the housing comprises a track in which the carriage is arranged to slide.

9. A safety mechanism according to claim 8, wherein the carriage comprises a pair of bearings arranged to engage the track.

10. A safety mechanism according to any preceding claim, wherein the second end of the arm is rotatably mounted to a mount, the mount being arranged for mounting to the structure.

11. An opening arrangement comprising:

a barrier hinge mounted to a structure defining an opening, and a safety mechanism according to any preceding claim;

wherein the housing is mounted to the barrier and the second end of the arm is pivotally mounted to the structure such that rotational movement of the barrier relative to the structure causes the arm to translate the carriage along the housing.

12. An opening arrangement according to claim 11, wherein the barrier is a door or a gate.