GB2367409A

GB2367409A - Shutter latch sensing switch

Info

Publication number: GB2367409A
Application number: GB0017102A
Authority: GB
Inventors: David Chisnall
Original assignee: AS Fire and Rescue Equipment Ltd
Current assignee: AS Fire and Rescue Equipment Ltd
Priority date: 2000-07-13
Filing date: 2000-07-13
Publication date: 2002-04-03
Anticipated expiration: 2020-07-13
Also published as: US6326899B1; GB2367409B; AU5411801A; AU776524B2; GB0017102D0

Abstract

A shutter, as used on a fire engine, consists of a number of hinged laths which can be drawn across an opening and latched in the closed position by a latch member 11 which closes on a bight 16. A sensor is housed within the bight 16 and comprises an emitter and detector. In the absence of the latch member 11, the signal transmitted by the emitter is not received by the detector. When the latch is closed, the signal transmitted by the emitter is reflected by the latch member 11 and received by the detector. The detector controls an electrical circuit that may be used, for example, to operate a warning light. The sensor may contain a second detector, which does not receive the signal transmitted by the emitter, but receives all other signals which are also received by the first detector when the latch member 11 is absent, to avoid false registration.

Description

1 2367409 This invention relates to shutters and is concerned in

particular with a sensor which registers if such a shutter is opened or closed by sensing whether the latch mechanism by which such a shutter is latched closed is engaged, and switching an electrical circuit accordingly.

5 U.S. Patent Specification No. 571361 discloses a vehicle rolling shutter with door-ajar and compartment light switch which uses a magnetically operated switch and requires a magnet to be fitted to the shutter latch to indicate whether the shutter is closed and that the latch is engaged. Other forms use mechanical switches that are operated by the latch whilst it is engaged, these having moving 10 parts which can be affected by water and movement of the latch during use of the vehicle.

An object of this invention is to provide a shutter with a latch sensing switch that has no moving parts and is less affected by water or the movement of the latch due to vehicle motion and that does not require the installation of a 15 magnet on the shutter latch.

According to this invention there is provided a shutter assembly comprising a structure which surrounds an opening, a shutter which comprises a plurality of laths hingedly connected together at their longitudinal edges and moveable across the opening in a direction substantially normal to those 20 longitudinal edges to open and close the opening, and a latch mechanism operable to retain the shutter in location in which it extends across the opening, the latch mechanism comprising at least one member mounted on the shutter and, for each latch member, at least one keeper which is mounted on the said structure and which has a portion with which the respective latch member co 25 operates to latch the shutter in the closed condition, and a sensor which detects and registers the presence of the latch member, movement of the latch member beyond a distance away from the sensor causing the sensor to register the latch members absence. The sensor being formed by an emitter and a detector, the emitter transmits a signal which is then reflected by the latch member and 30 received by the detector thereby registering the presence of the latch member, or in the absence of the latch member no signal is received by the detector registering the latch members absence. The said detector forms part of and controls an electrical circuit connected to it. Each sensor may contain a second detector that only receives signals transmitted by sources other than the said emitter which are also received by the first detector, the comparison of the 5 signals received by both detectors enabling incorrect registration of the presence of the latch member to be avoided. The signal may be in the form of, but not restricted to, light waves in the infrared spectrum. Conveniently the sensor can be totally contained within a keeper and can be used, with or without the use of an electrical relay switch included within or outside of the keeper, to 10 operate a warning light or other electrical or electrically controlled items.

Specific embodiments of this invention will now be described, by way of example only, and with reference to the accompanying drawings, of which-. Figure 1 is a fragmentary view in perspective showing the lower left hand corner of the shutter and the respective latch mechanism when the shutter is latched in 15 its closed position, the latch mechanism being viewed from outside the opening at a location displaced from the opening to the left of the opening; Figure 2 is a view similar to figure 1 illustrating disengagement of the latch mechanism during initial opening of the shutter; Figure 3 is a view similar to figures 1 and 2 illustrating the sensor within the keeper being viewed from outside the opening 20 at a location displaced from the opening to the left and below the opening; figure 4 is a diagrammatic illustration of a sensor with the latch member present and indicates -the path of signals; figure 5 is a diagrammatic illustration similar to figure 4 of a sensor with the latch member absent.

A vehicle such as a fire engine, has an opening which provides access to 25 a storage compartment. The opening is surrounded by a frame 10 (see figures 1 to 3) and is normally closed by a roller shutter. The roller shutter comprises a plurality of elongate laths, which are hinged together along their longitudinal edges. Any convenient hinge arrangement such as that which is described in British Patent No. 2,113,749, may be used. The lath (not shown) at one end of 30 the shutter is fixed to a storage roller which is mounted within the compartment adjacent to and substantially parallel to the upper edge of the opening. The storage roller is spring loaded in the direction in which it must rotate to draw the shutter across the opening so as to open the opening, the shutter being rapped around the roller as it is so drawn. A handle is provided on the outer surface of the shutter so that an operator can apply a load assisting the spring to open the 5 shutter or to restrain opening movement of the shutter so that it does not open too quickly and can move the shutter against the spring loading to close it.

Figures 1 and 2 show that the handle comprises at least one latch member 11 which is pivotally mounted on a respective mounting bracket 12 which is secured to the outer surface of the lath 13 of the roller shutter adjacent the 10 respective end of that lath 13. The or each latch member 11 is in a vertical plane which also contains for the or each latch member 11 a respective keeper 14 which is fixed to the frame 10 alongside the opening. The keeper 14 projects outwardly from the frame 10 parallel to the edge of the opening. Its upper surface forms a ramp 15 which slopes downwardly and outwardly from the 15 frame 10. The keeper 14 forms a bight 16 below the ramp 15. The horizontal depth of the bight 16 corresponds to the respective stop surface 17 of the latch member 11. The geometrical form of each latch member 11 is such that the stop surface 17 is located within the respective bight 16 (as shown in figure 1) whereby the shutter is latched against upward movement. Within at least one 20 keeper 14 there is a sensor 18 which comprises an emitter 19 and a detector 20 that are positioned such that when the stop surface 17 engages with the respective bight 16 the signal 21 transmitted by the emitter 19 is reflected by the stop surface 17 and is then received by the detector 20 as shown in figure 4.

The detector 20 on reception of the signal 21 allows the passing of an electrical 25 current through an electrical circuit (not shown) that is connected to said detector 20. When the respective latch member 11 is not present the signal 21 transmitted by the emitter 19 is not received by the detector 20 (see figure 5) and the said electrical current in the circuit (not shown) connected to the detector 20 is not permitted to pass by the said detector 20. The said circuit 30 connected to the detector 20 is also connected to an indicator light on the dashboard of vehicle (not shown) such that the said light is illuminated when the respective latch member 11 is registered as not being present thereby indicating that the shutter is either open or closed and not latched. An audible warning (not shown) controlled or generated by electrical means may be included together with or in place of the said warning light.

5 In certain embodiments, substantially as previously described and as shown in figures 1 to 5, where the form of the signal 21 may also be present from sources other than the emitter 19, the sensor 18 consists an emitter 19 and a first detector 20 and a second detector 22, wherein said second detector 22 is included and positioned such that it does not receive the signal transmitted by 10 the emitter 19 and or any other signals 23 whilst the latch member 11 is present (see figures 4). The said position of the second detector 22 also being such that when the latch member 11 is not present the second detector 22 receives any signals 23 that are also received by the first detector 20 thereby allowing signals 23 not originating from the emitter 19 received by the first detector 20 to be 15 cancelled by comparing the signals 23 received by both the first detector 20 and second detectors 22 by electronic means so that false registration of the latch member 11 may be avoided (see figures 5).

In other embodiments substantially as previously described and as shown in figures 1 to 5 the signal 21 is formed by light waves in the infrared spectrum.

20 Another embodiment, substantially as previously described and as shown in figures 1 to 5, where the said circuit connected to the detector 20 is connected, either directly or by the use of an electrical relay switch (not shown) which may be contained within the respective keeper or external to it, to at least one light within the storage compartment closed by the shutter. The said circuit 25 connected to the detector 20 is connected such that the said at least one light is illuminated when the respective latch member 11 is registered as not being present thereby illuminating the storage compartment when the shutter is opened. Electrically controlled items (not shown) may also be used in addition to or in place of the said at least one light.

Claims

1. A shutter assembly which comprises a structure which surrounds an opening, a shutter which comprises a plurality of laths hingedly connected together at their longitudinal edges and moveable across the opening in a 5 direction substantially normal to those longitudinal edges to open and close the opening, and a latch mechanism operable to retain the shutter in location in which it extends across the opening, the latch mechanism comprising at least one member mounted on the shutter and, for each latch member, at least one keeper which is mounted on the said structure and which has a portion with 10 which the respective latch member co-operates to latch the shutter in the closed condition, and a sensor comprising an emitter and a detector positioned such that when the latch member is engaged the signal transmitted by the emitter is reflected by the latch member and is then received by the detector which then registers the presence of the latch member by making or breaking an electrical 15 circuit for the duration of that presence, and the said position of the sensor also being such that when the latch member is not engaged with the keeper the signal from the emitter is not received by the detector and the said registration does not occur.

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2. A shutter assembly according to claim 1, wherein a second detector is included and positioned such that it does not receive the signal transmitted by the emitter and or any other signals whilst the latch member is present, and the said position also being such that when the latch member is not present the second detector receives any signals not originating from the emitter that are 25 also received by the first detector thereby allowing signals not originating from the emitter received by the first detector to be cancelled by comparing the signals received by both the first and second detectors so that false registration may be avoided.

3. A shutter assembly according to claims 1 or 2, wherein the signal transmitted by the emitter and received by the detector is composed of light in the infrared spectrum.

5

4. A shutter assembly according to any one of claims 1 to 3, wherein the sensor is housed within a keeper.

5. A shutter assembly according to claim 4, in which more than one keeper containing a sensor is used.

6. A shutter assembly according to any one of claims 1 to 5, wherein the or each sensor is connected to an indicator light which is switched on by the detector when the or a latch member is not engaged.

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7. A shutter assembly according to any one of claims 1 to 6, wherein the or each sensor is connected to at least one light fitted in a position within the boundaries of the structure and behind the closed shutter said at least one light being switched on by the detector when the or a latch member is not engaged.

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8. A shutter assembly according to any one of claims 6 or 7, wherein the switching of the at least one light is by the inclusion of an electrical relay switch.

9. A shutter assembly according to claim 8, wherein the relay switch and the sensor are both incorporated within a keeper.

10. A shutter assembly according to any one of claims 6 to 9, wherein an audio indicator or other electronic item may be substituted for or be in addition to the at least one light.

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11. A shutter substantially as described hereinbefore with reference to the accompanying drawings.