GB2047013A - Fire or smoke detector apparatus - Google Patents

Abstract

A fire or smoke detector apparatus includes a socket 1 adapted to be electrically coupled to a selected one of a plurality of different types of detector head (not shown). In the embodiment shown, the socket 1 includes a resiliently deformable portion 8 having projections 7 selectively engageable with recesses 5 or recesses 6 to locate the portion 8 in one of three positions. The portion 8 defines a gap 12 and a recess 9, and a part-circular projection 4 on the socket defines a further gap 3. The positions of the projections on the different heads are such that only a head whose characteristic corresponds to that selected by the position of the portion 8 can be coupled to the socket 1. Markings 13 on the socket 1 indicate the selected detector head characteristic. In other embodiments, screws or screwed on projection members are selectively positioned on the socket to determine which of the plurality of detector heads may be electrically connected thereto. <IMAGE>

Description

SPECIFICATION Fire or smoke detector apparatus This invention relates to a fire or smoke detector apparatus comprising a detector head and a socket plate, and more particularly to a fire or smoke detector apparatus wherein the detector head and the socket plate are provided with an improved coupling mechanism.

A detector apparatus which serves as a transmitter for transmitting a fire or smoke detection signal, generally comprises a socket plate secured to a ceiling or other surface and a detector head assembly including an electric circuit. Coupling terminals are respectively provided on the socket plate and the detector head, so that the detector head may be inserted into the socket plate. Preferably subsequent rotation between the plate and head can be carried out to provide locking engagement therebetween.

Generally, these detector heads are classified into types such as ionization smoke detectors, photoelectric smoke detectors, rate of heat rise detectors, a fixed temperature detector and the like, selection being dependent on the intended circumstances of use. These devices may be required safety equipment in homes as well as commercial areas. A socket plate which may commonly be used with any of the above types of detector heads, has been required in recent designs. That is, the engaging position of the metal coupling terminals is required to be identical regardless of the type of detector head so that each type of detector head can be lockingly coupled to a common socket plate. However, it is necessary to select a suitable detector head applicable to the location where the detector is to be utilized.For example, in view of a probability of explosion, a detector head having an electric switch or circuit breaker cannot be employed in the place where an explosive material is stored. Furthermore, a smoke detector cannot be employed in the place where dust scattered in the air exceeds allowable ranges. Accordingly, the selected detector head is required to be readily coupled to the corresponding socket plate. In this case, however, a possibility that an incorrect type of detector head may be coupled to the socket plate, either in initial installation or as a result of maintenance and inspection.

An object of this invention is to eliminate the above described difficulties accompanying conventional detectors.

According to the invention there is provided a fire or smoke detection apparatus comprising a socket and a detector head adapted to be electrically coupled to said socket, said socket including a portion which can selectively be positioned relative to the remainder of the socket to indicate a desired functional characteristic of the detector head to be coupled to the socket, and said detector head having a portion whose position on said head corresponds to said functional characteristics, inter-engagement of said socket and detector head portions being such that only a head having the characteristic indicated by the position of said socket portion can be coupled to said socket.

Preferred embodiments of the invention will be described with reference to the accompanying drawings, in which: Figure 7A shows the bottom view of a socket plate adapted to receive a photoelectric type smoke detector head; Figure 1B shows the top view of a photoelectric type smoke detector head for fitting to the plate of Figure 1A; Figure 1C shows the side view of the coupled socket plate and the detector head of Figures 1A and 1 B, including a part cross-sectional view taken along a line A-A in Figures 1A and 1 B; Figure 1D shows a bottom view of an embodiment of a socket plate adapted to receive an ionization smoke detector head; Figure shows a top view of a detector head for coupling to the socket plate of Figure 1 D;; Figure 2A shows a bottom view of an alternative form of socket plate adapted to receive a photoelectric type smoke detector head; Figure 28 shows the top view of a detector head for coupling to the socket plate of Figure 2A; Figure 2C shows a partially cross-sectional view of the coupled socket plate and the detector head of Figures 2A and 2B, taken along a line B-B of Figures 2A and 2B; Figure 3A shows the bottom view of an alternative form of socket plate adapted to receive a photoelectric type smoke detector head; Figure 3B shows the top view of a photoelectric type smoke detector head for coupling to the socket plate of Figure 3A; Figure 3C shows a partially cross-sectional view of the coupled socket plate and the detector head of Figures 3A and 3B, taken along lines C-C in Figures 3A and 3B;; Figure 4A shows the bottom view of a further embodiment of a socket plate; Figure 4B shows the top view of a photoelectric type smoke detector head adapted to cover the socket plate shown in Figure 4A, and Figure 4C shows the partially cross-sectional view of the coupled socket plate and the detector head of Figures 4A and 4B, taken along line D-D in Figures 4A and 4B.

Referring now to the accompanying drawings, and initially to Figures 1Ato 1 E, there is shown a first embodiment of a detector according to this invention, which includes a coupling mechanism for detachably coupling a detector head to a socket plate.

A socket plate 1 has a concave portion 100 adapted to receive a photoelectric type smoke detector head 15 therein. Metal coupling terminals 2a to 2d are provided on a base surface concentrically with respect to the centre thereof as shown in Figure 1 A.

One of these metal coupling terminals composes a pair of metal coupling pieces 2d and 2d' for instance, which are isolated from each other. A circular projection 4 having a cut-off portion 3 is integrally formed on the base surface of the concave portion 100. Two pairs of receiving holes 5 and 5', and 6 and 6' are provided to an inside periphery of the concave portion 100. In order to provide for selective cou pling of a photoelectric type detector head, a Cshaped resiliently deformable member 8 having a pair of protrusions 7 and 7' is fittingly inserted into concave portion 100 in such a mannerthat the protrusions 7 and 7' engage with the receiving holes 5 and 5', respectively. The receiving holes 6 and 6' will be described later in detail.Furthermore, abase end portion 10 of the C-shaped member 8 is formed to define a receiving recess 9, whereas two end portions thereof are configured to serve as grippers 11 and 11'. The interval between the grippers 11 and 11' defines a receiving portion 12. In the case where the C-shaped member 8 is positioned as shown in Figure 1a, it is desirable that an indication mark 13 of "PHOTO" appears on the receiving portion 12to visually designate the type of detection head to be coupled.

In order to move the position of the C-shaped elastic member 8 for the purpose of changing the designation ofthe detector head, the grippers 11 and 11' are squeezed together to release the engagement between the protrusions 7 and 7' and the receiving holes 5 and 5'. The member 8 may then be rotated to shift it to a desired position.

The outer periphery of photoelectric smoke detector head 15 is configured to fit with the inner periphery of the concave portion 100. On the top surface of the detector head 15, metal coupling terminals 16ato 16dare provided in such a manner that they can be coupled to the corresponding metal coupling terminals 2a to 2d of the socket plate 1, respectively. Three protrusions, 17, 18 and 19 are also provided on the top surface of the detector head 15, so that they are allowed to enter into the cut-off portion 3, the receiving recess 9 and the receiving portion 12 of the socket plate 1, respectively, and the detector head 15 can also be subsequently rotated in a clockwise direction in order to fixedly couple the detector head 15 to the socket 1 by interengagement of the terminals, in a known manner.As a result, the coupling between the socket plate 1 and the photoelectric type smoke detector head, which is best shown in Figure 1C, can be obtained. Upon the completion of coupling, the above described metal coupling pieces 2d and 2d' of the socket plate are electrically connected to each other through the corresponding metal coupling terminal 16d of the detector head to thereby produce a signal indicating the completion of coupling. Absence of this signal can provide an indication if the detector head is not fitted or is removed in error.

Where it is required to use an ionization type smoke detector head whose top surface is shown in Figure 1 E, the C-shaped elastic member 8 is moved in the aforementioned manner, so that the protrusions 7 and 7' engage with the other receiving holes 6 and 6', respectively, as shown in Figure 1 D. In this case, it is also desirable that an indication mark 14 of "ION" is shown in the receiving portion 12' defined by the gripppers 11 and 11', to visually indicate the kind of detector head to be fitted.

As shown in Figure 1 E, a difference between the photoelectric smoke detector head and an ionization smoke detector 20 in their top surfaces only exists in that protrusions 18' and 19' are positioned different lyfrom the protrusions 18 and 19. Accordingly, the ionization smoke detector head 20 cannot be coupled to the socket plate 1 when the latter is arranged for the photoelectric smoke detector 15 as shown in Figure 1A, since simultaneous insertion of the protrusions 17, 18' and 19' into the cut-off portion 3, the receiving recess 9 and the receiving portion 12 cannot be effected.

With the C-shaped member 8 arranged so that the protrusions 7 and 7' engage with the receiving holes 6 and 6' respectively, as shown in Figure 1 D, insertion of the respective protrusions 17, 18' and 19' into the cut-off portion 3, the receiving recess 9' and the receiving portion 12' may simultaneously be effected. Subsequent rotation of the head 20 in the clockwise direction can be carried out to obtain the engagements of the metal coupling terminals as described above.

It will be apparent that the photoelectric type smoke detector head as shown in Figure 1 B cannot be coupled to the socket plate 1 as shown in Figure 1D.

Figure 2A shows the bottom surface of a socket plate 21. The socket plate 21 in this embodiment has a concave portion adapted to receive a fire detector head 29 shown in Figure 28. A pair of arcuate projections 22 are symmetrically provided, instead of the above-described member 8, along the inside periphery of the concave portion, to define a pair of receiving portions 23. The receiving portions accept a pair of protrusions 30 of the detector head 29, one corresponding to the receiving recess 9 of the first embodiment and the other corresponding to the receiving portion 12 thereof. The protrusions 30 are concentrically symmetrically provided on the top surface of the detector head 29 as shown in Figure 2B. Metal coupling terminals 24a to 24dare provided at the same respective positions as in the embodiment of Figures 1A and 1 D.Similarly, metal coupling terminals 31a to 31 dare also provided on the head 29 at the same relative positions as in the embodiment of Figures 1B and 1 E. Furthermore, at the centre of the bottom surface of the socket plate 21, a cylindrical projection 25 is provided having an end surface with three grooves 26a to 26c radially formed with the same angle at the circumference.

Reference numeral 28 designates a member for selecting a kind of detector head to be equipped. The member 28 can be detachably secured into one of the grooves 26a to 26c by a screw 27 and can be located according to the type of detector head to be used. It is desirablethatthe bottom portions of the grooves 26a to 26c are labeled to indicate the type of detector head to be used, that is, "PHOTO", "ION" and "HEAT". For example, in the case where the photo-electric type smoke detector head is to be coupled to the socket plate 21, the member 28 is placed in the groove 26a and then screwed by the screw 27 as shown in Figure 2A. The top surface of the photoelectric type detector head 29 has a construction shown in Figure 2B. Specifically, the detector head 29 has an outside peripheral configuration adapted to be received by the concave portion of the socket plate.

On the top surface of the detector head 29, a sector-like concave portion 32a indicated by a solid line is provided together with the pair of protrusions 30 and the metal coupling terminals 31a to 31d similar to those which have been described above.

The sector-like concaved portion 32a is formed, so that it can receive the member 28 screwed in the groove 26a and it allows the detector head 29 to be rotated in the clockwise direction in order to fixedly couple the detector head 29 to the socket plate 21 and to effect interengagement of the metal coupling terminals. Positioning of the concave portion is in accordance with the type of detector head, and determines whether a head can be coupled to a selected socket plate configuration. For example, in the case where an ionization type smoke detector head is required to be coupled to the socket plate 21 as shown in Figure 2A, the member 28 is secured in the groove 26c.

The ionization type smoke detector head has a sector-like concave portion 32c at the position as indicated by a broken line in Figure 2B. Accordingly, the member 28 can be received by the concave portion 32c, whereas the pair of protrusions 30 are received by the receiving portions 23, respectively.

As a result, the proper engagement between the detector head and the socket plate 21 can be obtained and subsequent rotation in a clockwise direction can be carried out to fixedly couple those elements together by the engagement of the metal coupling terminals. A heat detector head for coupling to the plate 21 has a sector-like concaved portion 32b at the position as indicated by a broken line in Figure 28.

It is apparent that, although this type socket plate is commonly used with the photoelectric type and the ionization type smoke detectors and several kinds of heat detector heads, once the detector head to be equipped is designated by the member 28, it is impossible to couple different detector heads other than the designated detector head to the socket plate 21.

Referring to Figures 3A to 3C, a modification of the embodiment of Figures 2A to 2C is shown. A screw 33 which is engageable with a socket plate 35 is employed instead of the member 28 of Figures 2A to 2C. Instead of the sector-like concave portion 32a shown in Figures 2B, for example, an elliptically concaved portion 37a is provided on the top surface of the photoelectric type smoke detector head.

Furthermore, tapped holes 34a to 34c are provided for threadingly engaging with the screw 33 on the socket plate 35, instead of the cylindrical projection 25 and the grooves 26a to 26c. The other elements, for example terminals 38a to 38d and 39a to 39d, are the same as those of Figures 2A to 2C. The screw 33 may be substituted by force-fit pin. In this case, the tapped holes 34a to 34c should be replaced by holes having a depth and a diameter sufficient to prevent the pin from falling off.

Selection of the detector head to be coupled to the socket plate 35 can be achieved by replacing the screw 33 or pin. Figure 3A shows that the screw 33 is screwed into the tapped hole 34a to designate a photoelectric type detector head having the elliptically concaved portion 37a as shown in Figure 3B. In contrast, the heat detector head and the ionization smoke detector heads are provided with elliptically concaved portions 37b and 37c respectively as indicated by broken lines in Figure 3B.

While the aforementioned detector heads employed in the three different embodiments are inserted into the con-cavity of the socket plate, it is apparent that, a detector head which is designed to cover a socket may also be employed. For example, the top surface of the detector head shown in Figure 18 is modified to receive a socket shown in Figure 1A. Specificaliy, as shown in Figures 4B and 4C, a circular guide member 15' is provided to define a concave portion adapted to receive a socket plate shown in Figure 4A. It should be noted that the socket shown in Figure 4A is identical to that shown in Figure 1A and the same elements in these embodiments are designated by the same reference numerals.

Because the designation of detector head to be equipped is visibly and clearly indicated on the socket plate, prevention of an erroneous coupling of detector head can be enhanced. Furthermore, because the socket plate can be commonly used for alternative kinds of detector head by moving the member for designating the detector head to a suitable position, and the coupling mechanism is simple to construct, mass production thereof and reduction of the cost can be also achieved.

Claims (13)

1. A fire or smoke detector apparatus comprising a socket and a detector head adapted to be electrically coupled to said socket, said socket including a portion which can selectively be positioned relative to the remainder of the socket to indicate a desired functional characteristic of the detector head to be coupled to the socket, and said detector head having a portion whose position on said head corresponds to said functional characteristic, interengagement of said socket and detector head portions being such that only a head having the characteristic indicated by the position of said socket portion can be coupled to said socket.

2. The apparatus of Claim 1, in which said socket is provided with a plurality of markings which can selectively be indicated by the positions of said socket portions, to show said desired characteristic.

3. The apparatus of Claim 1, wherein said socket is generally circular having an inner portion and a series of receiving holes on the periphery of said socket and wherein said socket portion comprises a resiliently deformable member fitting in said inner portion and having a projection engaging at least one of said receiving holes.

4. The apparatus of Claim 3, wherein said elastic member is part circular.

5. The apparatus of Claim 4, wherein said socket has a plurality of indicia adjacent its periphery, whereby when said resilient member is shifted such that said projections engage different receiving holes, the indicia visible in a gap in said part-circular member designate said desired characteristics of the detector head.

6. The apparatus of Claim 1, wherein said socket is generally circular and said socket portion comprises an angularly positionable projection.

7. The apparatus of Claim 6, wherein said projection is shiftable to different portions about a center axis of said socket.

8. The apparatus of Claim 7, wherein said socket has a plurality of indicia disposed in positions adapted to be selectively covered by said projection to indicate said desired characteristics of the detector head.

9. The apparatus of any of Claims 6, 7 or 8, wherein said angularly positionable projection comprises a tab member extending from the center axis of said socket to a position radially outward in a sector.

10. The apparatus of Claims 6 or 7, wherein said projection comprises rod-like member and said detector socket has a plurality of spaced holes to selectively receive said rod-like member and, said member having a portion extending from said socket for engagement with an appropriate detector head.

11. The apparatus of Claim 10, wherein said rod-like member is a screw which can selectively be screwed into said spaced holes.

12. The apparatus of Claim 10,wherein said rod-like member is a pin for force fitting into said spaced holes.

13. A fire or smoke detector apparatus, substan tialiy as hereinbefore described with reference to anyof Figures 1Ato 1C,1D and 1E,2Ato 2C,3Ato 3C or 4A to 4C.