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(11) | EP 0 750 094 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Roller shutter auto-lock assembly |
| (57) A roller shutter assembly comprising a shutter formed from a plurality of hingedly
interconnected transverse slats slidably supported by spaced apart guide tracks; drive
means operable progressively to move the shutter between an open and a closed position;
connection means connecting the slats for relative movement between an open configuration
wherein adjacent slats are spaced apart to expose intermediate apertures and thereby
to allow light to pass through the shutter, and a closed configuration wherein adjacent
slats abut to substantially close the shutter; remote locking means (50) operable
to lock an end of the shutter remote from the drive means (5) in the closed position;
and a partial opening mechanism (31-41) to enable the drive means (5) to move the
shutter a predetermined amount toward the open position with the remote locking means
(50) simultaneously engaged, to draw the slats into the open configuration. |
[0002] The invention has been developed primarily for use in connection with roller shutters and will be described hereinafter with reference to this application. It will be appreciated, however, that the invention is not limited to this particular field of use.
[0003] Roller shutters are normally installed over windows so that when the shutter is open, the window is exposed and functions in the usual way. In the closed position, however, the shutter covers the window. Such shutters thereby provide a number of advantages including noise reduction, thermal insulation, control over light and air flow, protection against storms and bush fires, increased privacy, and security.
[0004] Roller shutters normally comprise a series of hingedly interconnected transverse slats which are slidably supported by spaced apart longitudinal guide tracks, disposed on either side of the window frame. A drive mechanism, either manual or electric, operates on the interconnected slats to open or close the shutter. Normally, although not necessarily, the drive mechanism operates to wind the slats to or from a roller, between the open and closed positions. In such cases, the roller and associated drive mechanism are normally housed within a head box positioned above the window frame. In other cases, such as overhead doors, the slats may simply be driven to or from a storage bay by a drive shaft.
[0005] In any event, the slats are typically connected by interlocking edge flanges which are designed with a degree of free play to permit relative translational movement between adjacent slats. Movement of adjacent slats apart from one another into an open configuration normally exposes a series of ventilation holes or slots formed in the interlocking edge flanges. This allows a limited amount of light and air to pass through, with the shutter itself remaining in the closed position. Conversely, movement of adjacent slats toward one another into a closed configuration conceals the ventilation slots and thereby substantially seals the shutter, so that neither light nor air may pass through.
[0006] Many known shutter arrangements also incorporate some form of locking mechanism to enhance security. One type of locking mechanism operates to remotely lock a lowermost slat or a bottom bar to the guide rails, with the shutter lowered in the closed position. However, there are several fundamental problems with such mechanisms. Firstly, many locking assemblies need to be disengaged manually, usually by means of a key, before the shutter can be raised. At best, this is an inconvenient and time consuming procedure. At worst, in the case of electrically driven shutters, inadvertent activation of the drive motor with the locking mechanism engaged can destroy the shutter.
[0007] In an attempt to address this problem, several shutter arrangements have been designed whereby actuation of the drive mechanism, whether electric or manual, to raise the shutter also operates to automatically release the locking mechanism. The fundamental problem with these designs, however, is that the shutter cannot be locked down with the slats apart in the open configuration to allow limited passage of light and air through the ventilation slots. This is because the cumulative back-lash effect resulting from the free play between each pair of slats can amount to a significant degree of movement at the drive roller (up to almost two full revolutions, in a reasonably long shutter). By the time this back-lash has been taken up, and the ventilation slots between all the slats are open, the locking mechanism has been disengaged. Thus, the shutter cannot be locked in a "partially open" configuration whereby the shutter itself is closed, but the slats are open to expose the intermediate ventilation holes.
[0008] Thus, EP-B-040,800 discloses a roller shutter assembly comprising a shutter formed from a plurality of hingedly interconnected transverse slats slidably supported by spaced apart guide tracks; drive means operable progressively to move the shutter between an open and a closed position; connection means connecting the slats for relative movement between an open configuration wherein adjacent slats are spaced apart to expose intermediate apertures and thereby to allow light to pass through the shutter, and a closed configuration wherein adjacent slats abut to substantially close the shutter; and remote locking means operable to lock an end of the shutter remote from the drive means in the closed position. In the case of such designs, the unlocking mechanism can usually be activated externally by a potential intruder. This is often possible simply by manually lifting the top of the shutter upwardly by an amount corresponding to the cumulative degree of free play between the slats, thereby rotating the drive roller in an opening direction by an amount sufficient to activate the automatic unlocking mechanism. This negates most of the benefit in providing a lockable shutter in the first place. Because of this problem, some shutters lock from the top, for example by locking the drive roller itself rather than a remote slat or bottom bar. However, the security of such designs is easily breached, simply by wedging a lever or crow-bar under the bottom slat or bar, particularly if the slats themselves are spaced apart in the open configuration, with the ventilation holes exposed. This affords sufficient leverage to pull the entire shutter from its guide tracks.
[0009] It is an object of the present invention to provide an improved roller shutter assembly which overcomes or substantially ameliorates at least some of these disadvantages of the prior art.
[0010] Starting from EP-B-040,800 the present invention is characterised in that a partial opening mechanism is provided to enable the drive means to move the shutter a predetermined amount toward the open position with the remote locking means simultaneously engaged, to draw the slats into the open configuration, thereby allowing a degree of light to pass through the open slats with the shutter remaining locked in the closed position.
[0011] The drive means preferably include a drive roller adapted to wind the shutter between the open and closed positions.
[0012] In the preferred embodiment, each pair of adjacent slats is connected by complementary interlocking edge flanges, at least one of which incorporates a series of said apertures. The apertures preferably take the form of ventilation slots formed in the edge flanges and disposed to permit the passage of both light and air with the slats spaced apart in the open configuration, and to substantially seal the shutter with the slats moved together in the closed configuration. It will be appreciated, however, that the apertures may also take the form of transparent or translucent windows, in which case light, but not necessarily air, would be permitted to pass through the open slats. The interlocking edge flanges preferably also provide the degree of pivotal interconnection between the slats required to enable the shutter to be wound onto the drive roller. Alternatively, however, the slats may simply be interconnected by flexible backing tape, or other suitable means.
[0013] The drive roller is preferably housed within a head box, and extends axially between spaced apart end plates. The roller preferably cooperates with a bearing assembly at each end. In one particular embodiment, a bearing assembly is incorporated at each end of the roller, each bearing engaging a complementary spigot protruding inwardly from the respective end plate. In an alternative embodiment, however, the roller may be journalled at each end in a bearing aperture or cavity provided in the respective end plate.
[0014] The locking means preferably comprise a spring loaded or gravity actuated latch mechanism disposed automatically to lock a lowermost slat or a bottom bar upon closing of the shutter.
[0015] The partial opening mechanism preferably comprises a ring gear mounted within one of the end caps, and driven by a complementary pinion mounted on the shutter drive roller. The ring gear preferably includes a trigger formation disposed to actuate a lock release mechanism once during each period of rotation of the ring gear. The gear ratio between the pinion and ring gear is preferably 2:1, so that the lock release mechanism is activated only once for each two full rotations of the shutter drive roller.
[0016] The preferred trigger mechanism includes a cam profile formed on the outer periphery of the ring gear. The cam preferably defines a ramped profile terminating in a protruding shoulder portion. The shoulder portion is preferably adapted to engage an actuating rod upon rotation of the drive roller in a shutter opening direction. The actuating rod preferably extends down one of the guide tracks to release the remote locking mechanism.
[0017] The cam profile preferably has an effective duration corresponding to around 16° of rotation of the drive roller, so that a minimum of approximately 16° of rotation of the drive roller is required to activate the trigger.
[0018] A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:-
Figure 1 is a diagrammatic perspective view showing the basic layout of a conventional prior art roller shutter assembly;
Figure 2 is an exploded perspective view showing in more detail a conventional drive mechanism for a roller shutter of the general type shown in Figure 1;
Figure 3 is a cross-sectional end elevation showing a shutter drive assembly incorporating a partial opening mechanism according to the present invention;
Figure 4 is a cross-sectional plan view showing the drive mechanism of Figure 3;
Figure 5 is a cross-sectional front elevation showing the shutter drive mechanism of Figures 3 and 4; and
Figures 6 to 8 are a series of diagrammatic cross-sectional side elevations showing progressively the operation of the remote locking mechanism according to the invention.
[0019] Referring to the drawings, Figures 1 and 2 show the general layout of a conventional prior art roller shutter assembly 1. This assembly comprises a plurality of hingedly interconnected transverse slats 2 slidably supported by spaced apart guide tracks 3 which are normally disposed on either side of a window or door (not shown). A drive mechanism 5 is housed within a head box 6 which is normally positioned above the window, between the guide tracks. The drive mechanism 5 includes a main drive roller 10, each end of which incorporates a threaded insert or plug 11 which in turn supports a central bearing assembly 12 (see Figure 2). Each bearing is engaged by a corresponding axial spigot 13 protruding inwardly from the adjacent end cap 14 of the head box.
[0020] The drive means further includes a drive spool 15 keyed internally to one end of the drive roller 10. The drive spool is actuated remotely by means of a flexible tape 17, which may be drawn either manually, electrically, or by any other suitable means, to progressively wind the shutter to or from the drive roller, between the open and closed positions.
[0021] Each adjacent pair of slats is connected by a corresponding pair of interlocking edge flanges (not shown), which define a series of longitudinally extending ventilation slots 20, as best seen in Figure 1. The edge flanges are designed to provide a degree of free play between adjacent slats which allows the slats to move apart from one another into an open configuration, wherein the ventilation slots 20 are exposed, to allow a limited degree of light and air to pass through the shutter whilst remaining in the closed position. The slats are also able to butt together into a closed configuration wherein the ventilation apertures 20 are concealed, and the shutter as a whole is thereby substantially sealed.
[0022] Thus, it should be appreciated that a distinction is being drawn between the open (wound up) and closed (wound down) positions of the shutter as a whole, and the open (spaced apart) and closed (butted together) configuration of the individual slats.
[0023] The interlocking edge flanges also provide the degree of pivotal interconnection required between the slats to enable the shutter to be wound onto the drive roller as the shutter is progressively closed.
[0024] Referring now to Figures 3 to 5, wherein corresponding features are denoted by corresponding reference numerals, the present invention is adapted to be integrated with the basic framework and components of a conventional shutter assembly as described above. However, the invention additionally provides a partial opening mechanism.
[0025] The partial opening mechanism 30 comprises an internal ring gear 31 which is rotatably supported by a housing 32 mounted to one of the end plates 14, and optionally retained by means of a cover plate 33. The internal ring gear is in constant meshing engagement with a pinion 35 which is integrally formed in the corresponding roller insert 11, and is thereby effectively integral and coaxial with the drive roller 10.
[0026] The external periphery of the ring gear incorporates a trigger mechanism in the form of a lifting cam 36 comprising a ramped portion 37, which terminates in a protruding shoulder portion 38. During counterclockwise rotation (when viewing Figure 3) of the ring gear, the cam shoulder 38 is adapted to engage a lifting finger 40 formed in the upper end of an actuating rod 41 which extends down the adjacent guide track 3 to remote locking mechanism (described below). As the cam 36 moves upwardly during anti-clockwise rotation, the outwardly protruding shoulder 38 engages and begins to move the lifting finger 40 upwardly. The lifting finger is constrained for movement along guide slot 43, whereby it is constrained progressively to move upwardly and outwardly, away from the lifting cam, against the action of return spring 45. At a predetermined point near the top of the guide slot 43, the lifting finger is released from the shoulder of the lifting cam, and returns together with the actuating rod to its original position, downwardly under the influence of gravity, and inwardly under the influence of the return spring 45. The gear ratio between the pinion and ring gear is preferably 2:1, so that the lock release mechanism is activated only once for each two full rotations of the shutter drive roller.
[0027] It will be appreciated that with the ring gear rotating in the clockwise direction (again in the orientation of Figure 3), the ramped portion 37 of the cam will simply displace the lifting finger radially outwardly against the return spring 45, without lifting the finger 40 or the associated actuating rod 41. When the cam profile has passed the lifting finger, it is displaced horizontally to its rest position by the return spring.
[0028] Figures 6 to 8 show the lower end of the actuating rod 41, and the associated remote locking mechanism, indicated generally as 50. In the preferred embodiment, the locking mechanism is integral with a transverse lower bar 51, which effectively comprises the lowermost slat of the shutter. The locking mechanism incorporates a pivotal latch 55 which, as best seen in Figure 6, is biased outwardly by latch spring 56. A locking tab 57 is mounted within the corresponding guide rail to prevent the shutter from being opened from the closed position with the pivotal latch protruding in the locked configuration (Figure 6).
[0029] As best seen in Figure 7, an upward stroke of the actuating rod 41, under the influence of lifting cam 36, draws a lock release cam 60 upwardly which retracts the pivotal latch 55 against the bias force of the latch spring 56. In this position, the latch clears the locking tab 57, thereby allowing the shutter to be opened.
[0030] As will be seen from Figure 8, once the latch clears lock release cam 60 and the locking tab 57, it is biased outwardly again by latch spring 56, ready to engage the locking tab automatically whenever the shutter is returned to the closed position.
[0031] Turning now to describe the operation of the partial opening mechanism in more detail,the shutter drive mechanism is installed with the meshing relationship or "timing" between the pinion and ring gear pre-set. This ensures that the lifting cam on the ring gear is positioned correctly relative to the lifting finger 40 on the actuating rod for a given length of shutter. This would normally be pre-set at the factory or on site, and would not change in use.
[0032] Commencing the description with the shutter fully open, the drive mechanism is initially activated to commence lowering of the shutter. During this movement, the drive roller 10 and associated pinion 35 rotate in a clockwise direction, when viewing Figure 3. The outer ring gear will of course rotate in the same direction and so the lifting cam will have no effect on the actuating rod, aside from periodically displacing it horizontally outwardly against the return spring 45.
[0033] When the shutter reaches the closed position, the pivotal latch 55, having cleared the locking tab 57, will be urged outwardly by spring 56 (Figure 6) thereby automatically locking the shutter in the closed position. At this point, the lifting cam 36 and lifting finger 40 (Figure 3) will be positioned in the pre-set relationship, ready for the opening phase of the cycle.
[0034] When the drive mechanism is subsequently activated, the drive roller, the associated pinion, and hence the ring gear will all begin to rotate in the anti-clockwise direction, thereby drawing the shutter upwardly from the top. During this initial opening phase, each slat is progressively lifted into the open configuration, thereby exposing the ventilation slots directly below it. This process continues downwardly toward the bottom of the shutter until all the slats are moved apart into the open configuration, with the remote locking mechanism still fully engaged. In this "partially opened" configuration, the ventilation slots allow a limited amount of light and air to pass through, whilst the shutter remains securely and positively locked in the closed position. The timing of the system is calibrated so that just prior to this point, the lifting cam 36 on the ring gear 31 begins to engage the lifting finger 40 of the actuating rod. Consequently, subsequent rotation of the ring gear by further actuation of the drive mechanism lifts the actuating rod upwardly. As the actuating rod 41 is elevated, the lock release cam 60 at its remote end is correspondingly lifted to retract the pivotal latch 55 from the locking tab 57. This effectively releases the locking mechanism, and allows the shutter to open. The guide slot 43 is configured such that, as soon as the pivotal latch 55 has cleared the locking tab 57, the lifting finger of the actuating rod is released from the lifting cam, thereby allowing the actuating rod 41 and the lock release cam 60 to drop down to their rest positions (see Figure 8). Further operation of the drive mechanism progressively winds the slats onto the drive roller, and thereby opens the shutter in the usual way.
[0035] It will be appreciated that the actuating rod and hence the lock release cam 60 will be similarly displaced upon each subsequent revolution of the ring gear, and hence upon every two subsequent revolutions of the shutter drive roller. However, with the locking mechanism already disengaged by the first pre-set movement of the lifting cam in the opening direction, these movements are redundant and do not affect the operation of the shutter in any way.
[0036] The angular duration of the lifting cam profile is such that approximately 16° of rotation of the shutter drive roller is required to activate the lock release mechanism. Accordingly, by adjusting the timing of the pinion with respect to the ring gear, the lock release mechanism can be calibrated to trigger anywhere in the range of 16° to 714° of rotation of the drive roller. The desired release point within this range will depend primarily upon the cumulative degree of free play in the slats, as they move between their open and closed configurations. For a given type of slat, this in turn will be a direct function of the length or "drop" of the shutter. However, once the timing has been pre-set it cannot self adjust in service, and therefore provides consistent and reliable operation.
[0037] It will be appreciated from the foregoing description that the present invention provides a shutter assembly with a remote locking mechanism which is both engaged and released automatically. Furthermore, it allows the shutter slats to be moved into the open configuration, thereby allowing light and air to pass through the ventilation holes, which the shutter itself remaining securely locked in the closed position. Thus, the invention represents a practical and commercially significant improvement over the prior art.
1. A roller shutter assembly comprising a shutter formed from a plurality of hingedly
interconnected transverse slats (2) slidably supported by spaced apart guide tracks
(3); drive means operable progressively to move the shutter between an open and a
closed position; connection means connecting the slats for relative movement between
an open configuration wherein adjacent slats are spaced apart to expose intermediate
apertures (20) and thereby to allow light to pass through the shutter, and a closed
configuration wherein adjacent slats abut to substantially close the shutter; and
remote locking means (50) operable to lock an end of the shutter remote from the drive
means (5) in the closed position; characterised in that a partial opening mechanism
(31-41) is provided to enable the drive means (5) to move the shutter a predetermined
amount toward the open position with the remote locking means (50) simultaneously
engaged, to draw the slats into the open configuration.
2. An assembly according to claim 1, characterised in that the locking means (50) comprise
a latch mechanism (55-57) biased automatically to lock a lowermost slat or a bottom
bar upon closing of the shutter.
3. An assembly according to claim 1 or 2, wherein said drive means (5) include a drive
roller (10) adapted to move the shutter between the open and closed positions, characterised
in that the partial opening mechanism comprises a ring gear (31) mounted within an
end cap (14) of the drive mechanism (5), and driven by a complementary pinion (35)
mounted on the shutter drive roller (10).
4. An assembly according to claim 3, characterised in that said ring gear includes a
trigger formation (38) disposed to actuate a lock release mechanism (41,60,57) once
during each period of rotation of the ring gear (31).
5. An assembly according to claim 4, characterised in that the gear ratio between the
pinion (35) and ring gear (31) is 2:1, so that the lock release mechanism is activated
only once for each two full rotations of the shutter drive roller (10).
6. An assembly according to claim 4 or 5, characterised in that said trigger mechanism
includes a cam profile (37) formed on the outer periphery of the ring gear.
7. An assembly according to claim 6, characterised in that said cam profile defines a
ramped profile terminating in a protruding shoulder portion (38), and in that said
shoulder portion (38) is adapted to engage an actuating rod (41) upon rotation of
the drive roller (10) in a shutter opening direction.
8. An assembly according to claim 7, characterised in that the actuating rod (41) extends
down one of the guide tracks (3) to release the remote locking mechanism (50).
9. An assembly according to claim 6, 7 or 8, characterised in that said cam profile (37)
has an effective duration corresponding to around 16° of rotation of the drive roller
(10), so that a minimum of approximately 16° of rotation of the drive roller is required
to activate the trigger.