GB2459884A

GB2459884A - A door handle mechanism

Info

Publication number: GB2459884A
Application number: GB0808398A
Authority: GB
Inventors: Rodney Caleb Dummer
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-05-09
Filing date: 2008-05-09
Publication date: 2009-11-11
Also published as: GB0808398D0

Abstract

A door handle mechanism 20, operable to be surface, recess or flush mounted to a door having a door latch 10 and/or lock 11 assembly, comprising: a body (21, fig.3), a substantially cylindrical handle (22, fig.3) rotatable about a first axis 23 on the body and a drive member 24 rotatable about a second axis 25 on the body, and operable to receive and rotate a spindle 16A of the door latch/lock assembly. Rotation of the handle causes rotation of the drive member 24 and the axes 23, 25 are substantially parallel to and spaced from one another. As shown the handle and drive member are interconnected by gearing but other means can be used such as belt or chain drives and electric or fluid motors. A clutch can be arranged in the transmission to effect force or movement limitation. The arrangement allows a handle which resists the attachment of a line, which can be large enough to provide effective grip without obstruction and which has a low rotational force. The handle mechanism is shown driving a latch bolt 13 and can accommodate a lock mechanism to drive a lock bolt 17. Alternatively the handle mechanism can be used to operate the lock bolt 17 (fig.9).

Description

A DOOR HANDLE MECHANISM

Description of Invention

THE PRESENT INVENTION relates to a door handle mechanism intended to be mounted on a door for operating a door latch assembly and/or door lock assembly. The door latch or lock assembly may be conventional and comprise a latch or lock mechanism and, in particular, may be of the kind known as a mortise sash lock and the handle mechanism according to the invention is suitable for retrofitting to these known door latch or lock assemblies.

A door is often provided with some sort of handle, which the user rotates in a given direction to operate a latch mechanism to open the door. A known door handle comprises a lever arm, rotatable about one end. The length of the lever arm provides a suitable moment arm for the user to open the latch mechanism with minimum effort. Another known door handle comprises a rotatable knob, which the user grips with their hand and rotates in a predetermined direction to operate the latch mechanism.

Further, a door is often provided with a lock mechanism, in addition to or instead of the latch mechanism. It is known to provide a rotatable knob to operate the lock. The knob may be of a similar shape to that used on the latch mechanism but is generally smaller. Some latch and lock assemblies comprise a single handle which is used to operate both the latch and lock mechanism. In some doors, there is no operable latch mechanism provided but only a locking mechanism. In addition, such arrangements may comprise a roller ball latch, which does not need to be "operated", per Se, but is biased so as to engage the door with the door frame.

The above types of door handle are suitable for most domestic and commercial applications. However, they may pose a significant risk when used in environments accommodating people with mental health problems, people who are liable to suicide attempts or self harm; or otherwise violent individuals.

When used in such environments, known door handles provide a suitable attachment point for a ligature, with which a person may attempt suicide.

Furthermore, because the door may be the only access route into a room, it may be difficult to access the room to administer medical attention because the person may be blocking the door or have jammed the handle with another object. Moreover, these known door handles may pose a risk of impalement for the occupant.

However, simply removing the handle is not possible, because there is still a requirement for doors in these environments to have a latch and/or lock assembly, for reasons including privacy and fire regulations.

Attempts have been made to provide an improved door handle for use in such environments. For example, GB2413068 discloses a door handle which is arranged such that a ligature or barricade cannot easily be attached thereto. It is similar to a known lever door handle, but is fixable to the door such that the lever arm is always pointing downwards in any configuration. It is intended that any ligature or barricade wrapped around the handle will likely release due to the taper and gravity.

However, such handles still pose a significant danger, as they provide an anchor point to which one end of a ligature may be attached and tensioned upwards or outwards. The other end of the ligature may be tied to a further anchor point, for example another item of furniture or wall fitting within the room. The downward sloping handle may also facilitate a barricade.

An improved door knob has also been proposed, having a substantially frustoconical shape. (The diameter may be in the region of 50 mm, though could be smaller or larger). In much the same way as the improved door handle described above, the shape is such that any ligature wrapped around the handle will likely fall off due to the taper or gravity. However, one noted disadvantage with such a knob is that its shape and/or size may not allow the user to achieve an adequate grip to turn the knob. This may be dangerous when an occupant of the room needs quickly to escape. Disabled users may be unable to turn the knob. Another disadvantage is users may need to pull on a separate handle at the same time to pull open the door.

There is a need to provide a door handle mechanism which overcomes at least some of the above noted problems.

However, at the same time, there is a requirement that such an improved door handle mechanism is compatible with known door latch or lock mechanisms, so that wholesale replacement of the latch or lock mechanism or other door furniture is not necessary.

One known door latch assembly includes or comprises a mortise sash lock 1, shown in figures 1 and 2. A mortised aperture is formed in a sidewall 2 of a door 3. A further aperture is formed in one or both of the front 4 and rear 5 surfaces of the door, the aperture(s) communicating with the mortice. The mortice lock 1 is then inserted into the mortised aperture. The mortice lock 1 may fit the mortice with an interference fit. A door handle mechanism 6 may be affixed to either or both of the front 4 and rear 5 surfaces of the door 3, such that the door handle mechanism 6 is operably connected to the mortice lock I, through the corresponding aperture. The mortice sash lock 1 may be operated by turning the, or either, door handle mechanism 6.

The known mortise sash lock I as shown in figure 2 comprises a mounting plate 7 and a main body 8. The main body 8 is inserted into a mortice in a door 3. The mounting plate 7 preferably sits within a recess in the sidewall surface 2 of the door 3 and its top surface is flush with that of the sidewall 2. The mounting plate 7 may be secured to the door 3 by screws. The mortice lock 1 comprises a latch mechanism 10 and a locking mechanism 11.

The latch mechanism 10 comprises a latch member 13 protruding from the mounting plate 7. In use, the latch member 13 may engage with and be received in a corresponding aperture provided in a striker plate 14 fitted to the door frame 15 or another door. The latch mechanism 10 is operated by the rotation of a square-section spindle 16A insertable into the spindle aperture 16 in the mortice lock 1. The latch member 13 may be biased to a protruding position. A surface of the latch member 13 may be ramped or curved so as to aid the latch member being received in the striker plate 14. In another embodiment, the latch may comprise a roller latch, as is known in the art.

The locking mechanism 11 comprises a locking bar 17, which acts as a bolt.

The locking bar 17 is movable between a protruding (locked) position; and a position where the locking bar 17 is held substantially within the locking mechanism 11 (open position). The locking bar 17 may also be receivable in a corresponding aperture in the striker plate 14. The locking mechanism 11 is operable to move the locking bar 17 between an open and closed position.

The locking mechanism 11 may comprise a key lock cylinder (not shown), into which a user may insert a key. If the correct key is used, the user may rotate the key in a predetermined direction, and the key lock mechanism moves the locking bar between an open and locked position. Alternatively, the locking mechanism may be operated by a turn knob (e.g. a thumbturn). The knob may be provided on both sides of a door, or one side may have a knob; the other a key lock. In other arrangements, the key operated double cylinder may be replaced with a single cylinder which only protrudes on one side of the door, limiting access rights to users on the other side of the door.

As shown in figure 2, the locking mechanism 11 may comprise an aperture 18 to receive the key lock cylinder. The key lock cylinder may be removably securable in the locking mechanism 11. The benefit of such an arrangement is that the key lock cylinder may be replaced without the need to replace or disassemble the locking mechanism 11 or door latch assembly I itself. A well-known key lock cylinder is a Euro-profile cylinder, which is widely used in the industry and is securable in known mortice locks and other latch assemblies.

Other well known cylinders are Oval-profile cylinders or rim cylinders.

In another arrangement the locking mechanism 11 may be operated in a similar fashion to the latch mechanism described above -i.e. by the use of a spindle that may have a square-section Known door handles are normally designed so that they are compatible with known mortise sash locks 1, latch mechanisms 10, lock mechanisms 11 and key and/or turn lock cylinders. It is possible, therefore, to select a door handle and/or door handle mechanism largely based on aesthetic form only, because they will be compatible with the existing parts in or on the door 3. Users do not want to have to replace existing parts in or on the door 3.

An improved anti-ligature door handle mechanism has been proposed having a large circular handle in order to offer a suitable grip to users but the handle is of such a diameter and size that it is not compatible with a standard mortice lock or door latch assembly. As a result in general, a special mortise lock or door latch assembly is required such that the edge of the handle is located a sufficient distance from the door edge or door frame. If this known anti-ligature door handle mechanism was used with a standard mortise lock or door latch assembly, the handle would interfere with the door edge and/or frame, hindering effective operation (i.e closing) of the door and even causing damage thereto. The known anti-ligature door handle mechanism may also interfere with the locking cylinder on a standard mortise lock or door latch assembly.

There is an additional requirement, therefore, that an improved door handle mechanism must be compatible with known mortise locks and door latch assemblies 1.

Accordingly, the present invention provides a door handle mechanism intended to be mounted on a door for operating a door latch and br door lock assembly, the mechanism comprising: a body; a substantially cylindrical handle, mounted on the body and rotatable aboutafirstaxis;and a drive member mounted on the body and rotatable about a second axis to engage and rotate a spindle of the door latch and/or lock assembly, wherein the handle and drive member are operably connected to one another within the body such that rotation of the handle causes rotation of the drive member; and wherein the first and second axes are substantially parallel to and spaced from one another.

The door handle mechanism may be surface, recess or flush mounted on the door.

The present invention further provides a door handle mechanism, an anti-ligature door handle mechanism, and a door as claimed in the appended claims.

Embodiments of the present invention will now be described, by way of example only, with reference to the figures, in which: FIGURE 1 shows part of a door fitted with a known mortise lock (commonly termed a sash lock) and a known door handle mechanism; FIGURE 2 shows a perspective view of the mortise lock of figure 1; FIGURE 3 shows a perspective view of one embodiment of a door handle mechanism embodying the present invention; FIGURE 4 shows a side view of the door handle mechanism of figure 3; FIGURE 5a shows a perspective view as seen from above of the door handle mechanism of figure 3, with the cover removed; Figure 5b shows a perspective view as seen from below of the door handle mechanism of figure 3 with the back plate removed.

FIGURE 6 shows a plan view of the door handle mechanism of figure 3, with the cover removed; FIGURE 7 shows a modification of the door handle mechanism of Figures 3 to 6 in use on a door; FIGURE 8 shows another modification of the door handle mechanism in use on a door; and FIGURE 9 shows another modification of the door handle mechanism in use on a dead bolt on a door.

Figure 3 shows a door handle mechanism 20 embodying the present invention, for operating a mortice lock such as shown in figure 2. The mechanism 20 comprises a body 21 and a substantially cylindrical handle 22.

The handle 22 is mounted on the body 21 and is rotatable about a first axis 23 (see figures 5a, 5b and 6). Further, the mechanism 20 comprises a drive member 24 including a gear wheel 31 (shown in figures 5a, 5b and 6) rotatable about a second axis 25 and operable to drive a spindle such as square-section spindle 16A of figure 2. The drive member 24 comprises a recess 26 to receive the spindle (see figure 5b and 6). The recess may be provided in the gear wheel 31 of the drive member 24. The recess 26 may be a blind recess 26. Advantageously, the recess 26 may be substantially square in cross section. The spindle may be received in the recess 26 with an interference fit and/or the spindle may be secured therein by the use of a grub screw or adhesive. Rotation of the drive member 24 causes rotation of the spindle. The spindle is connected, in use, to a latch mechanism 10 and rotation of the spindle in a given direction causes the latch assembly to operate in a known manner.

As more clearly shown in figures 5a, 5b and 6, the handle 22 is operably connected to the drive member 24. As a result, rotation of the handle member 22 causes a corresponding rotation of the drive member 24. In the embodiment shown, the handle 22 and drive member 24 are mechanically connected to one another with gearing as described below such that rotation of the handle 22 in one direction causes rotation of the drive member 24 in the same direction. A belt or chain drive may alternatively be used. There alternatively may be a magnetic or fluid drive. There may be two 90° (right angle) drive gearboxes with a drive shaft therebetween. The connection may be a linkage.

In another arrangement, the handle and drive member could be operably connected by electrical connection means. For example, rotation of the handle 22 may operate a switch (not shown). The switch may, in turn, operate a motor connectable to the spindle. In another embodiment, the door handle mechanism may comprise motor drive means to at least partially assist with the rotation of the drive member.

The handle 22 is concentric and integral with a gear wheel 27 and is mounted on a shaft (not shown). The door handle mechanism 20 further comprises a gear hub 28, pivotably mounted in the body 21 about an axis 35. The gear hub 28 has a first gear wheel 29 and a second gear wheel 30. The teeth of first gear wheel 29 of the gear hub 28 mesh with the teeth of the gear wheel 27 of the handle 22.

The teeth of the second gear wheel 30 of the gear hub 28 mesh with the teeth of the gear wheel 31 of the drive member 24. The diameter of the first gear wheel 29 of the gear hub 28 is larger than the diameter of the second gear wheel 30 of the gear hub 28, thereby providing a mechanical advantage.

Preferably, the mechanical advantage is 2:1. In another embodiment, the mechanical advantage may be 3:1, 4:1 or greater. The mechanical advantage may be chosen based on the force needed to operate the latch mechanism 10.

The mechanical advantage may be adjustable. There alternatively may be no mechanical advantage (1:1).

A known door latch assembly I may be operated (between a closed and open state) by rotating of the spindle 16A 1/8 of a turn. With a door handle mechanism 20 embodying the present invention having a mechanical advantage of 2:1, the handle therefore needs to be turned 1/4 of a turn to turn the drive member 1/8 of a turn.

In modifications there may be a clutch provided between the handle 22 and drive member 24. For example, the handle 22 and the gear wheel 27 provided thereon may be rotatable with respect to one another. The clutch may be provided between the handle 22 itself and the gear wheel 27. The clutch may be configured such that any excess force imposed on the handle 22 will be taken up by the clutch and not imparted on the gear mechanism or, more importantly, the drive member 24, which may otherwise damage the latch mechanism 10. Further, the clutch may be configured such that any rotation of the handle 22 beyond a predetermined point or angle is taken up by the clutch and not transferred to the gear mechanism or drive member 24.

Alternatively, or additionally, a clutch may be provided between the first 29 and second 30 gears of the gear hub 28. Alternatively, or additionally, the gear 31 of the drive member 24 may be rotatable with respect to the drive member 24 itself, and a clutch may be provided between the two.

The clutch may be adjustable, so that its sensitivity can be set according to the intended operating conditions.

The handle 22 may be biased in a particular rotational position. In one embodiment, the biasing may be provided by a torsional spring arranged between the handle 22 and the shaft on which it is mounted. The handle 22 may be biased to a position which causes the drive member 24 -by means of the operable connection -to urge the latch member 13 into a closed condition.

The biasing means may be provided elsewhere in the door handle mechanism 20, as with the clutch described above. The biasing means may be integral with the clutch mechanism.

The handle 22 is of a substantially cylindrical shape. As shown in figure 5a, the handle may comprise a raised portion 32 for gripping the handle 22 to impart a rotational force thereto. The raised portion 32 may be diametric -extending across the front face of the handle 22. The diameter of the handle 22 is such that it affords a suitable moment arm, allowing the user to impart a rotation force on the drive member 24 with relatively little effort. Thus, the handle embodying the present invention may readily be used by the infirm.

Alternatively, the front surface of the handle 22 may be provided with blind apertures therein, allowing a user's fingers to engage therewith and to turn the handle 22.

The handle is preferably configured so that a user may apply a pulling force thereto, thereby being able to open the door.

The diameter of the handle 22 may be between 50mm and 150mm and is such that the handle cannot directly be mounted coaxially with the spindle 16A of a known door latch assembly 1. This is because the distance (marked D in figure 2) between the axis of rotation of the spindle 16A in the door latch assembly I and the mounting plate 7 of the door latch assembly 1 is normally a standard size which is 50mm and the handle would extend up to or beyond the edge of the door. Further, the handle would impact upon, or otherwise interfere with the door edge and/or door frame.. The distance A in Figure 2 is measured between the axis of rotation of spindle 16A and the centre of the aperture 18 of the locking mechanism 11 (e.g. the axis of rotation of a cylinder lock insertable in the aperture 18). Distance A may be 45 mm, although may vary depending on the manufacturer or the mortise lock 1. Preferably, the diameter of the handle of the present invention is greater than twice the distance D of the door latch assembly to which it may be fitted, i.e.greater than 90mm A particular advantage brought about by the use of a cylindrical handle 22 of the present invention is that there is a reduced risk of a ligature being attached to the handle but also the shape and size of the handle 22 does not require a high rotational force to operate the latch assembly. The handle can also be used to pull open the door, as described above.

The present invention provides a handle 22 rotatable about a first 23 axis and a drive member 24 rotatable about a second 25 axis, which axes 23, 25 are substantially parallel to and spaced from one another. A synergistic benefit of this is that the handle 22 may be shaped and sized so to allow ease of use but also that the door handle assembly 20 may readily be operably engaged with a spindle of a standard door latch assembly 1. There is no need, with a door handle mechanism 20 embodying the present invention, to provide a new door latch assembly 1 having a larger distance D (and requiring a larger space to be mortised in the door) or to replace any other parts of the door latch assembly 1 (e.g. new lock cylinders).

Conveniently, therefore, the door handle mechanism 20 of the present invention may readily be retrofitted to an existing door latch assembly I as a complete and self-contained unit.

The body 21 comprises a rear mounting plate 33 and a cover 34. The mounting plate 33 has a surface to allow it to be surface, recess or flush mounted to a door 3. The handle 22, drive member 24 and gear hub 28 may be rotatably mounted on the mounting plate 33. The cover 34 substantially encloses the gear hub 28 and drive member 24 therein. Only a top portion of the handle 22 may protrude through an aperture in the cover 34. Preferably, the cover 34 is tamper proof. The cover 34 may be ruggedised to withstand attack. The cover 34 may comprise strengthening ribs. Preferably, the cover 34 is made of impact resistant plastic or equivalent.

The perimeter of the handle 22 is substantially flush with the front surface of the body 21, as shown in figures 3 and 4. Preferably, the entire front surface of the handle 22 is flush with the front surface of the body 21.

The form of the handle 22 of the present invention is particularly advantageous because it is free from any protrusions around which a ligature may be tied, but enables the door to be pulled open at the same time. Preferably, the aperture in the body cover 34 has a diameter slightly smaller than the largest diameter of the handle 22. Preferably, the aperture provides a skirt, preventing any foreign object, such as a ligature, being inserted into the mechanism between the aperture and handle.

The door handle mechanism 20 may comprise an anti-ligature door handle mechanism.

As described above, the door latch assembly 1 may also comprise a conventional locking mechanism 11 and the body 21 of the door handle mechanism 20 is configured so as to allow free access to the locking mechanism 11 by the key of a user. As shown in Figure 7, the door handle mechanism may comprise an aperture 37 to allow free access to a lock mechanism on or in the door 3. The lock mechanism may be a Euro-profile cylinder as described above. It may be a lock having a thumb-turn handle or knob, which protrudes through the aperture. There may be provided a lock having a key cylinder on one side of the door and a thumbturn knob which may be have a clutch on the other side. This further demonstrates how the door handle mechanism 20 of the present invention may be retrofit to an existing door latch assembly I without hindering its operation or requiring the replacement of any parts.

The door handle mechanism 20 may itself comprise at least a part of a locking mechanism 11. The locking mechanism may be housed within the body of the door handle mechanism 20 and may be arranged so as to engage with a further part of a locking mechanism 11 in the door latch assembly I itself. For example, the locking mechanism 11 in the door latch assembly I may be driven by a spindle, as with the latch mechanism 10. The door handle mechanism 20 may comprise a locking drive member (not shown), operable to receive and rotate the spindle of the locking mechanism.

The locking drive member may operably be connected to the handle 22 or drive member 24. Thus, operation of the handle 22 may also operate the locking mechanism 11 of the door latch assembly 1.

In one modification of the arrangement shown in Figure 7, there may be no aperture 37 in the door handle mechanism to allow access to the lock mechanism. The door handle mechanism would instead act as a shield to prevent access to the lock mechanism 11 from that side of the door. Access through the door may therefore be controllable.

In a further modification, shown in Figure 8, the arrangement of the handle, gear hub and drive member may be slightly different, where the drive member is mounted in another corner of the body. The function of the door handle mechanism is the same. Conveniently, this arrangement allows free access to an existing lock mechanism 11 (which could be a key cylinder or thumbturn).

There is no need to replace the lock mechanism 11 as the door handle mechanism 20 of the present invention may be entirely complementary with the lock mechanism 1.

In a further modification, shown in Figure 9, the door handle mechanism may operate a lock mechanism 11 only. There may be no latch, as such, but may be instead a ball or roller catch 36 as described above.

As will be seen from Figures 7 to 9, the door handle mechanism is configurable in multiple arrangements, allowing the door handle mechanism to be retrofit to an existing door latch assembly or mortice lock in any one of a number of arrangements required. Conveniently, no significant alterations or replacement of parts of the existing door latch assembly or mortice lock will be required.

The door handle mechanism 20 of the present invention may further comprise an electronic interface, connectable to a locking mechanism 11. For example, the electronic interface may comprise swipe card reader or proximity fob sensor, connectable to a solenoid operated locking mechanism 11. When a user swipes an access card or presents a proximity fob, the door handle mechanism 20 may operate the locking mechanism 11.

The door handle mechanism 20 may further comprise a status indicator (not shown), operable to indicate the state of the door latch 10 and/or locking mechanism 11. For example, the status indicator may indicate, by means of a coloured indicating disk, whether the locking mechanism 11 is in a locked or open state. The indicator could be remote and electrical, presenting the status on a control board.

The same or a further indicator may be operable to indicate when the locking mechanism 11 and/or latch mechanism 10 were last operated. This is beneficial where the occupant of a room must periodically be monitored. The indicator may monitor the time elapsed since either or both the locking mechanism and/or latch were operated. If the time is over a predetermined threshold, an alarm may sound or an indication be given.

The door handle mechanism of the present invention is also applicable to lock mechanisms 11 as described above. For example, the drive member may be operable to engage and rotate a spindle of a door lock assembly. In one embodiment, the door handle mechanism may be operable to engage the spindles of both the latch mechanism 10 and lock mechanism. 11. The same handle may operate both. For example, rotating the handle by a predetermined amount in one direction may open the latch; and rotation in the other direction may lock the lock mechanism 11.

A door handle mechanism 20 embodying the present invention may be provided on both sides of a door 3. Each end of a spindle may be received in the respective drive member 24 of each door handle mechanism 20.

Alternatively, one side of the door may not be provided with the door handle mechanism but instead have a standard handle or be fitted with a cover plate, preventing access to all or part of the door latch assembly.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS1. A door handle mechanism, intended to be mounted on a door for operating a door latch and/or lock assembly, the mechanism comprising: abody; a substantially cylindrical handle mounted on the body and rotatable about a first axis; and a drive member mounted on the body and rotatable about a second axis to engage and rotate a spindle of the door latch and/or lock assembly, wherein the handle and drive member are operably connected to one another within the body such that rotation of the handle causes rotation of the drive member; and wherein the first and second axes are substantially parallel to and spaced from one another.
2. A door handle mechanism according to claim 1, intended to be surface, recess or flush mounted on the door..
3. A door handle mechanism according to any preceding claim, configured such that, in use, the first axis is further from the edge of the door than the second axis.
4. A door handle mechanism according to any preceding claim, wherein the handle and drive member are operably connected to one another such that rotation of the handle member in one direction causes rotation of the drive member in the same direction.
5. A door handle mechanism according to any preceding claim, wherein the handle and drive member are mechanically connected to one another.
6. A door handle mechanism according to claim 5, wherein the mechanical connection is by at least one of gearing, belt or chain drive.
7. A door handle mechanism according to any preceding claim, having a mechanical advantage between the handle and drive member.
8. A door handle mechanism according to any preceding claim, wherein the handle is mounted on a rotatable shaft.
9. A door handle mechanism according to any preceding claim, wherein a portion of the handle comprises a gear wheel.
10. A door handle mechanism according to claim 9, comprising a gear hub pivotably mounted in the housing having a first and second gear wheel, the first gear wheel engaging with the gear wheel of the handle; and the second gear wheel engaging a gear wheel provided on the drive member.
11. A door handle mechanism according to claim 10, wherein the diameter of the first gear wheel of the hub is larger than the diameter of the second gear wheel of the hub.
12. A door handle mechanism according to any preceding claim, further comprising a clutch between the handle and drive mechanism.
13. A door handle mechanism according to claim 12, wherein the clutch isadjustable.
14. A door handle mechanism according to any of claims 10 and 11, wherein the gear hub is mounted on a shaft and the mechanism comprises a clutch between the gear hub and the shaft.
15. A door handle mechanism according to claim 14, wherein at least a part of the clutch is provided within the gear hub.
16. A door handle mechanism according to any preceding claim, wherein the handle is biased in a predetermined position.
17. A door handle mechanism according to any preceding claim, wherein the handle is biased in a position which causes the door latch or lock to close.
18. A door handle mechanism according to any preceding claim, wherein the drive member comprises a recess to receive and engage the spindle.
19. A door handle mechanism according to claim 18, wherein the recess is substantially square in cross section.
20. A door handle mechanism according to claim 18, wherein the dimensions of the recess are configured such that the spindle is receivable therein with an interference fit.
21. A door handle mechanism according to any preceding claim, further comprising a motor drive means to at least partially assist with the rotation of the drive member.
22. A door handle mechanism according to any preceding claim, wherein the handle comprises a raised portion for gripping the handle to impart a rotational force thereto.
23. A door handle mechanism according to claim 22, wherein the raised portion is diametric.
24. A door handle mechanism according to any preceding claim, wherein the handle is configured for gripping the handle to impart a pulling force.
25. A door handle mechanism according to any preceding claim, wherein the perimeter of the handle is substantially flush with the front surface of the body.
26. A door handle mechanism according to any preceding claim, wherein the front surface of the handle is substantially flush with the front surface of the body.
27. A door handle mechanism according to any preceding claim, comprising an aperture to receive at least a part of a locking mechanism.
28. A door handle mechanism according to any preceding claim, further comprising at least a part of a locking mechanism
29. A door handle mechanism according to claim 28, wherein the locking mechanism is at least partially operably connected to the handle or drive member.
30. A door handle mechanism according to any preceding claim, further comprising an electronic interface, connectable to a locking mechanism.
31. A door handle mechanism according to claim 30, wherein the electronic interface comprises a swipe card reader or proximity fob sensor, connectable to a solenoid operated locking mechanism.
32. A door handle mechanism according to any preceding claim, further comprising a status indicator, operable to indicate the state of the door latch and/or locking mechanism.
33. A door handle mechanism according to claim 32, wherein the status indicator is operable to indicate when the locking mechanism and/or latch was last operated.
34. A door handle mechanism according to any preceding claim, wherein the body substantially encloses the mechanism and comprises a rear surface operable to be mounted to the surface of a door.
35. A door handle mechanism according to any preceding claim, wherein mechanism is substantially tamper proof.
36. An anti-ligature door handle mechanism according to any preceding claim.
37. A door comprising a door latch assembly, a spindle passing therethrough, and a door handle mechanism according to any preceding claim.
38. A door comprising a door lock assembly, a spindle passing therethrough and a door handle mechanism according to any of claims I to 36.
39. A door according to claim 37 or 38, comprising a door handle mechanism, according to any preceding claim, on each side of the door, the drive member of each mechanism receiving a respective end of the spindle.
40. A door handle mechanism substantially as hereinbefore described with reference to the figures 3-9.
41. Any novel matter or combination thereof hereinbefore described.