EP1709606A1

EP1709606A1 - Fire detector

Info

Publication number: EP1709606A1
Application number: EP04820355A
Authority: EP
Inventors: Bernd Siber; Stefan Sittenauer
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2004-01-16
Filing date: 2004-11-23
Publication date: 2006-10-11
Anticipated expiration: 2024-11-23
Also published as: WO2005069243A1; JP4083199B2; JP2006520057A; DE502004006154D1; DE102004002592A1; US20080246618A1; EP1709606B1; US7696896B2

Abstract

The invention relates to a fire detector comprising a base (20) and a fire detector insert which can be connected to the base (20). The fire detector insert is essentially connectable to the base (20) by means of an axial movement and can be detached from the base (20) by a consecutive axial movement.

Description

fire alarm

State of the art

The invention relates to a fire detector according to the preamble of claim 1. Fire detectors for

Early detection of fires in areas with a corresponding fire load to protect people and property. Fire detectors are usually mounted on the ceiling and have a round, white housing with a diameter of approx. 10 cm and a height of approx. 7 cm to 10 cm. Due to their function, the housing sits on the ceiling. Fire detectors are industrial series products and fire detectors of one type and manufacturer usually look the same. The corresponding housing size can usually be recognized immediately on the ceiling as a fire alarm in rooms with public traffic. The uniformity of series production and the shape of the housing always represent a compromise between the function of the fire detector and the taste of the user and the visual requirements of the environment. Scattered light fire detectors are mainly installed on ceilings because the smoke is first transported to the ceiling due to the thermal generated by the fire and then spreads along the ceiling. This has the disadvantage that the installation, maintenance and functional testing of the fire detector must be carried out on the ceiling. At least one ladder is required for these activities, and often even a lift is required for higher rooms. This leads to a high expenditure of time and money in the activities mentioned. It is therefore desirable to be able to carry out the maintenance and regular functional tests of the fire detectors with test devices mounted on a long rod. A defective fire detector should also be easy to replace with a tool insert mounted on a rod. For this reason, almost all fire detectors are installed in a base to which the necessary supply and transmission lines are permanently connected. There are contacts in the base via which the fire detector is connected to these lines. Even when commissioning a fire alarm system for the first time, the fire alarm should be mountable in the base using such a tool insert, since the installation and wiring of the base is often carried out by another company and sometimes at greater intervals before installing the fire alarm itself. A ladder or lifting platform is only required for wiring the base. The fire detectors are installed in the base, as is known, for example, from WO 97/05586, predominantly by the fact that the fire detector, in the manner of a bayonet catch, is in a certain position

Orientation inserted in the base and fastened with a rotary movement. The tool insert on the installation tool used to install the fire detector in the base is therefore adapted to the shape of the fire detector to apply the frictional force required for the rotary movement via a positive connection.

From DE 101 18 913 AI a scattered light smoke detector is known which has a light transmitter and a light receiver, which are arranged such that a scattering point is outside the scattered light smoke detector, the scattered light smoke detector being a cover for protecting the light transmitter and the light receiver, and means for Distinction between smoke and other foreign bodies that are in an area around the scattering point. The means for differentiating between smoke and other foreign bodies have a processor for analyzing the time profile of received signals from the light receiver, the processor being connectable to the light receiver. The technology used to detect a fire on this scattered light smoke detector enables the scattered light smoke detector to be installed essentially flush with the ceiling. This is an important step in terms of an inconspicuous installation of such fire detectors. However, such a fire detector that can be installed flush with the ceiling requires that it essentially only has a flat, or only slightly curved and smooth surface, which is formed by a cover plate covering the fire detector. It is therefore extremely difficult to install such fire detectors with a rotary movement in a base. On the one hand, only comparatively low frictional forces can be transmitted via the smooth, flat surface of the fire detector. Much lower frictional forces than a form fit that is common with conventional fire detectors. In the worst case, the friction force that can still be applied is no longer sufficient to achieve the

Snap fire detector contacts to the base contacts. On the other hand, since the fire detector is now flush with the ceiling after being inserted into the base It is likely that the assembly tool will drag along the ceiling during the required rotational movement and become dirty or even damaged.

From DE 101 18 913 AI a scattered light smoke detector is also known which has two light receivers or an imaging optics for a light receiver for setting a defined measurement volume.

10 advantages of the invention

The fire detector designed according to the invention with the features of claim 1 offers the advantage of easy installation and

15 Disassembly for maintenance purposes or the like. In the present invention, a fire detector is described in which a fire detector insert of the fire detector can be installed in its base and removed again by a movement in the axial direction, that is, perpendicular to the ceiling in the base. The fire detector insert is pressed into the base during installation and is firmly locked in the base after being released. The fire detector insert is removed from the base by pressing the fire detector insert again in the axial direction and

25 then relieve the pressure on the fire detector insert. Since there are essentially two defined mounting states here, this solution can also be referred to as a "mechanical flip-flop". This type of mounting is made possible by latching means which have a linkage that is mounted centrally and rotatably in the base

, 0 include. With this backdrop, lugs arranged on the fire detector insert interact, which cooperate with obliquely running control surfaces of the backdrop and convert axial movements of the fire detector insert into a rotary movement of the backdrop. A convenient mounting position between is particularly useful

.5 the fire detector insert and the base by a mechanical Ensured coding that an assembly of the

Fire detector insert in the base only in a certain position.

drawing

The invention is explained in more detail below with reference to the drawing. It shows

FIG. 1 shows the rear of the fire detector insert of a flush-mounted fire detector,

Figure 2 shows the base of a flush-mounted fire detector;

FIG. 3 shows a backdrop in perspective,

FIG. 4 shows a longitudinal section through the backdrop shown in FIG. 3,

FIG. 5 is a backdrop with a representation of the rotary movement of a nose engaging in the backdrop during the assembly of the fire detector insert,

FIG. 6 shows a backdrop with the rotation of a nose engaging in the backdrop during the dismantling of the fire alarm insert,

Figure 7 shows another embodiment of a backdrop.

Description of the invention

Figure 1 and Figure 2 of the drawing show components of a flush-mounted fire detector. 1 shows a view of the rear of a fire detector insert 1. FIG. 2 shows a view of the inside of a base in which the fire detector insert shown in Figure 1 can be installed. A cover plate still required for covering the fire detector insert is not shown in the drawing, since the invention relates essentially only to new features of the fire detector insert 1 and the base 20. The fire detector insert 1 has on its rear side an essentially hollow cylindrical projection 9. Both on the inner circumference and on the outer circumference of the projection 9 there are projections 3, 5 projecting radially inwards and radially outwards, the function of which will be discussed further below becomes. Furthermore, grooves 6, 7, 8 are arranged on the outer circumference of the fire detector insert 1. In its central area, the fire detector insert 1 continues to carry electrical contacts 2, which correspond to the corresponding ones

Contacts 21 in the base 20 of the fire detector correspond. The base 20 of the fire detector shown in FIG. 2 is essentially hat-shaped and is intended for installation in a correspondingly deep recess in a ceiling. The brim of the hat-shaped base 20 lies in the installed position on the ceiling. Radially inwardly projecting lugs 25, 26 are arranged on the inner circumference of the base 20, which correspond to the grooves 6, 7, 8 arranged on the fire detector insert 1 and form a mechanical coding in order to achieve a specific orientation of

Fire detector insert 1 and base 20 to guarantee each other. A dome 35 is arranged concentrically in the interior of the base 20. The dome 35 is surrounded by a rotatably mounted link 23 which is held by a washer 24 fastened by means of a screw 33. The disc 24 is rotatably connected to the dome 35. The link 23 rotatably arranged around the dome 35 is also arranged rotatably with respect to the disk 24. However, locking means 31, 34 allow defined locking positions between the link 23 and the disk 24. The link 23 shown in FIGS. 3, 4, 5, 6 and 7 bears on its outer circumference inclined control surfaces, which correspond to the lugs 3 present in the fire detector insert 1. In the case of the axial movement of the fire detector insert 1 with respect to the base 20 necessary for the assembly or disassembly of the fire detector insert 1, a force is transmitted to control surfaces of the link 23 via the lugs 3, which results in a rotational movement of the link 23. The base 20 further comprises a compression spring 22 which concentrically surrounds the dome 35. This compression spring 22 loads the fire detector insert in the installed position with a compressive force and thereby secures it in a latched position.

The assembly of the fire detector insert 1 in the base 20 of the fire detector is described below. The fire alarm insert 1 is first carefully placed on the base 20 and rotated until a position is reached in which the fire alarm insert 1 can be pressed into the base 20 due to a mechanical coding in the fire alarm insert 1 and in the base 20. The mechanical coding is provided by lugs 25, 26 protruding inwards in the radial direction

The inside of the base 20 causes the form-fitting grooves 6, 7, 8 to engage on the outer circumference of the fire detector insert 1. The mechanical coding ensures that contacts 2 on fire detector insert 1 and contacts 21 on base 20 meet in the correct position. In contrast to conventional fire detectors, only a very small amount of force is required for the rotary movement mentioned, since only the appropriate position for the coding means has to be brought about. This low effort can also be easily applied to fire detectors that can be installed flush with the ceiling. After the coding means have been brought into line, the final installation of the fire detector insert 1 in the base 20 takes place by pressure on the fire detector insert 1 in the axial direction. Due to this pressure, the fire detector insert 1 moves into the Interior of the base 20. The contact surface 4 on the back of the fire detector insert 1 meets the compression spring 22 arranged centrally in the base 20. An essentially hollow cylindrical projection 9 protrudes from the back of the fire detector insert 1. This approach 9 carries on its outer surface four radially outwardly projecting lugs 5, which hold the compression spring 22 on the support surface 4 and prevent the compression spring 22 from sliding sideways during the relative movement between the fire detector insert 1 and the base 20. The spring force of the compression spring 22 is appropriately dimensioned such that it together with the weight of the fire detector insert 1 is sufficient to overcome the frictional force of the contacts 2, 21 between the fire detector insert 1 and the base 20 when the fire detector insert 20 is removed from the base 20. The

The length of the compression spring 22 is dimensioned such that when the fire detector insert 1 is inserted into the base 20 there is still no connection between the compression spring 22 and the support surface 4, as long as the mechanical coding prevents the fire detector insert 1 from being pressed into the base 20. This is necessary, otherwise rotating the

Fire detector insert 1, due to the friction between the spring 22 and the bearing surface 4, the spring 22 would be biased, which could make it more difficult to push the fire detector insert 1 into the base 20. Pushing the

Fire detector insert 1 in the base 20, both lugs 3 meet the backdrop 23. The backdrop 23 is rotatably mounted in the base 20 and is supported by a washer 24 which is fastened by means of a screw 33 (FIG. 2, FIG. 3, FIG. 4) , The setting 23 is aligned in the base 20 such that the lugs 3 meet the setting 23 in two mutually opposite regions M (FIG. 3). In these areas M, the backdrop 23 each has two sloping surfaces. The correct orientation of the areas M relative to the lugs 3 is ensured as follows: The mechanical coding between the fire detector insert 1 and the base 20 by means of grooves 6, 7, 8 and lugs 25, 26 defines the relative orientation of the fire detector insert 1 and thus also the position of the two lugs 3 relative to the base 20. The disk 24 is fastened with a screw 33 to a dome 35 protruding from the base 20 (FIG. 4). The orientation of the pane 24 relative to the base 20 is also determined by mechanical coding. In this case, this is achieved by a recess 32 in the disk 24, into which correspondingly shaped projections 36 engage, which protrude from the end face of the dome 35. Further bores 31 are made in the disk 24, into which lugs 34 protruding from the link 23 engage. Four bores 31 are expediently provided, which are evenly distributed on one

Circular arcs are arranged horizontally, i.e. they are 90 ° apart. Correspondingly, four lugs 34 are provided which engage in the bores 31. With the help of these bores 31 and lugs 34, the correct position of the areas M of the link 23 in relation to the base 20 is set. If the lugs 3 hit the backdrop 23 outside the areas M of the backdrop 23, then it would not be possible to insert the fire detector insert 1 into the base 20. The backdrop 23 is geometrically designed such that there is sufficient space between the backdrop 23, the base 20, the dome 35 and the disk 24 mounted on the dome 35. This ensures that the link 23 remains rotatable even after the disk 24 has been installed. In the installed position of the base 20, the base 20 is mounted in a corresponding recess in the ceiling, the four lugs 34 of the link 23 are then held in the associated bores 31 of the disk 24 by gravity. In the ideal case, the height h2 of the link 23 above the lugs 34 is dimensioned such that it corresponds exactly to the distance h1 between the disk 24 and the base 20 or is somewhat smaller. This ensures that the noses 34 in - lü ¬

the corresponding holes 31 remain. Now, as a result of an axial movement of the fire detector insert 1 inserted correctly into the base 20, the lugs 3 meet in the areas M, e.g. at position 1 (Figure 5) on the backdrop 23, then the backdrop 23 rotates with the other

Push fire detector insert 1 into base 20 until position 2 is reached. Here the rotational movement of the link 23 ends first, since the lugs 3 now slide along a surface of the link 23 aligned parallel to the longitudinal axis of the link 23 and therefore do not exert any torque on the link 23. In the further course of the axial movement of the fire detector insert 1, the lugs 3 again meet in position 3 on an inclined surface of the link 23, as a result of which torque is again exerted on the link 23. As a result, the link 23 continues to rotate about the dome 35 until position 4 is reached. In position 4, the fire detector insert 1 is pushed furthest into the base 20. If the fire detector insert 1 is relieved of the axial pressure again, then the compression spring 22, supported by the weight of the fire detector insert 1, pushes the fire detector insert 1, seen from the surface of the ceiling, vertically downwards until the nose 3 in position 5 again meet the backdrop 23. This in turn exerts a torque on the link 23, which then continues to rotate until position 6 is reached. In this position, the fire detector insert 1 is firmly locked in the base 20. Compared to its starting position, the link 23 is now rotated by approximately 45 °. The sequence of movements when the fire detector insert 1 is removed from the base 20 will now be described with reference to FIG. 6. To remove the fire detector insert 1 from the base 20, pressure is again applied to the fire detector insert 1 in the axial direction. As a result, the fire detector insert 1 again moves in the axial direction and is thereby pressed deeper into the base 20 again. Starting from the locking position of the lugs 3 in position 6 of the link 23, the lugs now return to an inclined surface of the link 23 in position 7 and therefore apply torque to the link 23 again. Under the influence of this torque, the link 23 continues to rotate until the lugs 3 have reached the position 8. If the fire detector insert 1 is now relieved of the applied axial pressure, then it moves, acted upon by the pressure of the compression spring 22 and gravity downward, that is, seen in the axial direction out of the base 20. The lugs 3 of the fire detector insert slide along a surface which is again parallel to the longitudinal axis direction of the link 23, and do not exert any torque on the link 23. In position 9 the lugs 3 in turn meet an obliquely positioned control surface of the link 23. As a result, a torque is exerted on the link 23, which now continues to rotate until the lugs 3 of the fire detector insert in position 10 are parallel to the longitudinal axis direction of the link 23 Reach aligned control surface of the backdrop 23 and are now released from the backdrop 23. Overall, the setting 23 has rotated by approximately 90 "in comparison to its initial state before the fire detector insert 1 was inserted into the base 20. After the fire detector insert 1 has been removed from the base 20, the setting 23 is in turn fixed by the lugs 34 which are shown in FIG the holes 31 arranged in the disk 24 snap into place.

Of course, in a further exemplary embodiment of the invention it is also possible to interchange the position of the link 23 and the position of the lugs 3 interacting with the link 23. This means that in this exemplary embodiment the backdrop would be connected to the fire detector insert 1 itself, while the lugs 3 interacting with the backdrop 23 would be connected to the base 20 of the fire detector. Since, as described above, essentially only a force has to be applied in the axial direction in order to To fix the fire detector insert 1 in the base 20 or to detach it from the base 20, the inventive solution is particularly advantageous for so-called flush-mounted fire detectors which have no parts protruding from the level of the ceiling to which a force acting in the radial direction is applied could.

The behavior of the locking mechanism described above can be optimized by the following influencing variables. When the link 23 rotates, a certain frictional force must be overcome. If the fire detector insert 1 is pressed into the base 20 with a predeterminable force F, then the fraction Fsin (α) is available for the rotary movement, where α is the slope of the control surfaces connected to the link 23. Furthermore, during the rotation of the link 23, the lugs 3 move on the link 23, which leads to an additional frictional force. This frictional force is proportional to Fcos (α). The greater the slope of the control surfaces, the lower the force F with which the fire detector insert 1 must be pressed into the base 20 in the axial direction in order to move the link 23 due to this relationship.

The slope α can expediently be increased by increasing the number of regions M for a given diameter of the link 23. Furthermore, the slope can be increased by reducing the diameter of the link 23 for a predeterminable number of areas M. Finally, the slope ex can also be increased by the fact that the area between two end points of the obliquely extending control surfaces of the link 23 is not designed as a straight line, but rather a larger slope ot> α is provided in the middle area between the end points. With the same height h3 (FIG. 3), the slope near the two end points of the end faces must then be reduced. If the size of the area in which the slope is reduced is smaller than the dimensions (diameter) of the lugs 3, then the function of the backdrop is not affected. Then it is ensured that when the nose 3 strikes the link 23 (in position 3) the point of contact between the nose and the link comes to lie in the area of the control surface with the larger slope α. If the end of the control surface is reached in position 4, the point of contact between the nose 3 and the control surface is still in the region of the control surface with the larger slope α.

An advantageous further embodiment variant of a link 23 is described below with reference to FIG. 7. The backdrop 23 is designed such that the area M of the backdrop 23, which the nose 3 arranged on the fire detector insert 1 meets, now forms an opening angle of 90 °. In addition, at least one projection 23.1 of the link 23 is designed as a triangle. In addition, the nose 3 is designed as a triangle. This has the advantage that the nose 3 can now meet the backdrop 23 in any relative orientation with respect to the backdrop 23. The orientation of the link 23 relative to the base 20 therefore no longer necessarily has to be set by the disk 24.

After the fire detector insert 1 has been pushed into the base 20 and locked there, the weight of the fire detector insert 1 must be borne by the two lugs 3. In addition, the lugs 3 must withstand the spring force of the now tensioned compression spring 22. The larger the dimensions of the lugs 3, the more stable they are. However, as the size increases, the dimensions of the link 23 inevitably increase, and thus the path that the fire detector insert 1 has to travel perpendicular to the ceiling when it is inserted. The larger this path, the larger the dimensions of the base 20 and thus also the recess required for the installation of the fire detector in the ceiling. It may therefore be more than two lugs 3 may be necessary to increase the mechanical stability with small dimensions of the lugs 3.

Claims

Expectations

1. Fire detector comprising a base (20) and a fire detector insert (1) which can be connected to the base (20), characterized in that the fire detector insert (1) can be connected to the base (20) essentially by an axial movement and by a subsequent axial movement of the base (20) is detachable.

2. Fire detector according to claim 1, characterized in that the fire detector comprises latching means which lock a fire detector insert (1) introduced by a first axial movement into the base (20) in a first latching position and the fire detector insert (1) after a subsequent second axial movement release a second locking position.

3. Fire detector according to one of the preceding claims, characterized in that the base (20) of the fire detector carries a centrally arranged, from the bottom (20.1) of the base (20) outstanding dome (35).

4. Fire detector according to one of the preceding claims, characterized in that the dome (35) is essentially hollow cylindrical and that the dome (35) on its end face facing away from the bottom (20.1) of the base (20) has at least one from the end face of the Doms (35) carries excellent lead (36).

5. Fire detector according to one of the preceding claims, characterized in that the base (20) comprises a disc (24) which by means of a through the bore of the dome (35) screw (33) on the dome (35) or the base (20) is attached.

6. Fire detector according to one of the preceding claims, characterized in that the disc (24) is rotatably connected to the dome (35).

7. Fire detector according to one of the preceding claims, characterized in that the disc (24) has at least one recess (32) into which a protrusion (36) protruding from the dome (35) engages, whereby the disc (24) rotatably with the cathedral (35) is connected.

8. Fire detector according to one of the preceding claims, characterized in that the disc (24) carries at least one bore (31), which runs at a distance from the center of the disc (24) parallel to a surface normal, introduced into the disc (24) is.

9. Fire detector according to one of the preceding claims, characterized in that the base (20) comprises a backdrop (23) which is rotatably mounted around the dome (35) on the dome (35).

10. Fire detector according to one of the preceding claims, characterized in that the link (23) comprises latching means for the purpose of latching with the pane (24).

11. Fire detector according to one of the preceding claims, characterized in that the latching means consist of at least one nose (34) which protrude from the end face of the link (23) facing away from the base (20.1) of the base (20).

12. Fire detector according to one of the preceding claims, characterized in that the height (h2) of the link (23), measured over the nose (34) projecting from an end face of the link (23), essentially corresponds to the height (hl) or is slightly smaller than this, the height (hl) corresponding to the distance of the disc (24) from the bottom (20.1) of the base (20).

13. Fire detector according to one of the preceding claims, characterized in that the link (23) carries obliquely inclined control surfaces on its circumference, and that a torque can be exerted on the link (23) by the action of force on the control surfaces, whereby the backdrop can be set in rotation is.

14. Fire detector according to one of the preceding claims, characterized in that the control surfaces of the link (23) with lugs (3) arranged on the fire detector insert (1) can be brought into operative connection in such a way that by an axial movement of the fire detector insert (1) the link (23) can be rotated.

15. Fire detector according to one of the preceding claims, characterized in that at least one projection (23.1) of the link (23) is designed in the form of a triangle.

16. Fire detector according to one of the preceding claims, characterized in that the fire detector insert (1) carries on its rear side a substantially hollow cylindrical projection (9), which after the installation of the fire detector insert 5 (1) in the base (20) in the base (20) arranged dome (35) concentrically surrounds.

17. Fire detector according to one of the preceding claims, characterized in that a plurality of radially outwardly projecting lugs (5) are provided on the outer circumference of the extension (9).

18. Fire detector according to one of the preceding claims, characterized in that the lugs (5) on the circumference of the approach

15 (9) are evenly distributed.

19. Fire detector according to one of the preceding claims, characterized in that on the inner circumference of the extension (9) in the radial direction inwardly projecting lugs (3) are provided

20 are.

20. Fire detector according to one of the preceding claims, characterized in that at least two lugs (3) are provided which are diametrically opposite.

> 5 21. Fire detector according to one of the preceding claims, characterized in that the fire detector insert (1) and the base (20) are provided with coding means for the purpose of unambiguous alignment with one another.

10 22. Fire detector according to one of the preceding claims, characterized in that radially inwardly projecting lugs (25, 26) are provided as coding means in the base (20), which in form-fitting grooves (6, 7, 8) in the outer circumference of the Intervene in the fire detector insert (1).

3. Fire detector according to one of the preceding claims, characterized in that the base (20) comprises a compression spring (22) which concentrically surrounds the dome (35) and which fixes the fire detector insert (1) in the latched position in the installed position.