GB2078004A - Fire alarms - Google Patents

Fire alarms Download PDF

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Publication number
GB2078004A
GB2078004A GB8107286A GB8107286A GB2078004A GB 2078004 A GB2078004 A GB 2078004A GB 8107286 A GB8107286 A GB 8107286A GB 8107286 A GB8107286 A GB 8107286A GB 2078004 A GB2078004 A GB 2078004A
Authority
GB
United Kingdom
Prior art keywords
pin
terminal device
alarm terminal
casing
frangible member
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB8107286A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ashworth Thomas & Co Ltd
Original Assignee
Ashworth Thomas & Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ashworth Thomas & Co Ltd filed Critical Ashworth Thomas & Co Ltd
Priority to GB8107286A priority Critical patent/GB2078004A/en
Publication of GB2078004A publication Critical patent/GB2078004A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B53/00—Internal-combustion aspects of rotary-piston or oscillating-piston engines
    • F02B53/04—Charge admission or combustion-gas discharge
    • F02B53/08—Charging, e.g. by means of rotary-piston pump
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C1/00—Rotary-piston machines or engines
    • F01C1/30—Rotary-piston machines or engines having the characteristics covered by two or more groups F01C1/02, F01C1/08, F01C1/22, F01C1/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
    • F01C1/34—Rotary-piston machines or engines having the characteristics covered by two or more groups F01C1/02, F01C1/08, F01C1/22, F01C1/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F01C1/08 or F01C1/22 and relative reciprocation between the co-operating members
    • F01C1/356—Rotary-piston machines or engines having the characteristics covered by two or more groups F01C1/02, F01C1/08, F01C1/22, F01C1/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F01C1/08 or F01C1/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the outer member
    • F01C1/3566—Rotary-piston machines or engines having the characteristics covered by two or more groups F01C1/02, F01C1/08, F01C1/22, F01C1/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in group F01C1/08 or F01C1/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the outer member the inner and outer member being in contact along more than one line or surface
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
    • F01C11/00—Combinations of two or more machines or engines, each being of rotary-piston or oscillating-piston type
    • F01C11/002—Combinations of two or more machines or engines, each being of rotary-piston or oscillating-piston type of similar working principle
    • F01C11/004—Combinations of two or more machines or engines, each being of rotary-piston or oscillating-piston type of similar working principle and of complementary function, e.g. internal combustion engine with supercharger
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
    • G08B25/12—Manually actuated calamity alarm transmitting arrangements emergency non-personal manually actuated alarm, activators, e.g. details of alarm push buttons mounted on an infrastructure
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fire Alarms (AREA)

Abstract

A fire alarm comprises a frangible member 3 which is supported in a predetermined position so as to restrain the actuating member of an electrical switch from assuming an actuating position, whereby the fire alarm may be actuated by breaking the frangible member 3, and means for releasing the frangible member 3 from the predetermined position to test the fire alarm. The releasing means comprises a pivotal member or a rotatable pin 2 which is movable between a first position in which the frangible member 3 is retained and a second position in which the frangible member 3 is released. The rotatable pin 2 may have lugs or bars 5, 6 which engage abutment surfaces in a casing of the device. <IMAGE>

Description

SPECIFICATION Alarm terminal devices The present invention relates to an alarm terminal device the operation of which can be tested.
Fire alarm devices must be checked and tested periodically to ensure that they are functional. In fire alarm devices of the type which are operated by breaking a glass plate to release a spring loaded switch, testing is often time consuming and awk ward since for obvious reasons the fire alarm device cannot be tested simply by breaking the glass plate.
Instead the glass plate has to be removed. This is usually achieved by releasing a frame in which the glass plate is housed. Replacing the glass plate after testing is difficult as the glass plate and frame must be held in position against the spring pressure of the switch whilst fixing devices such as screws are manipulated into position.
It is an object of the present invention to provide a fire alarm terminal device in which the above mentioned problems are obviated or mitigated.
According to the present invention, there is pro vided an alarm terminal device comprising an electrical switch biased to a switch actuating posi tion, a frangible member, means for supporting the frangible member in a predetermined position so as to restrain the actuating member from assuming the said actuating position, whereby the alarm device may be actuated by breaking the frangible member, and means for releasing the frangible member from said predetermined position to test the fire alarm terminal device, characterised in that the releasing means comprise means pivotal between a first position in which the frangible member is retained in said predetermined position and a second position in which the frangible member is free to move from said predetermined position.
According to a first embodiment of the present invention the frangible member is retained in said predetermined position by a clamping member which is releasably secured in position by a pin which extends from the clamping member through an aperture in a portion of a casing of the fire alarm terminal device. The pin supports projections in the form of for example bars or lugs which in the said first position abut against the rear surface of the said portion of the casing, preventing removal of the pin and thereby securing the clamping member in position, and in the said second position are able to pass through at least a portion of the aperture in the casing, enabling the pin to move axially to release the clamping member, the pin being movable be tween the first and second positions by pivoting about its own axis.
Preferably the projections on the pin are lugs which in the said second position are movable through slots running the length of the aperture in the casing portion through which the pin passes. To prevent the removal of the pin from the aperture when in the second position the pin may be extended beyond the said projections and additional projections offset from the first may be provided towards the end of the pin. Preferably said additional projections are lugs. The head of the pin may be shaped so as to prevent its movement except with a suitable tool.
The end of the pin may be made from a resilient material and formed with a slot between the said additional projections, whereby the pin may be inserted into the casing by forcing the additional projections together so that they may pass through the casing aperture.
According to a second embodiment of the present invention the frangible member is retained in said predetermined position by a securing member held in said first position by resilient means and pivotal between said first and second positions by means of a lever portion of the securing member.
Preferably the lever is acted upon to pivot the securing means between said first and second positions by a pin pushed through a hole in the terminal device casing located adjacent the lever.
In both embodiments means may be provided to visually indicate the supply of power to the fire alarm terminal device and to visually indicate actuation of the electrical switch. When the electrical switch comprises contacts which are open in the nonoperating mode, this visual indication may be provided by connecting an LED and resistor in series across the contacts.
Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a rear perspective view of part of a fire alarm device embodying the present invention; Figure 2 is a section on the line 2-2 of Figure 1; Figure 3 is an end view in the direction of arrow 3 of Figure 2; Figure 4 is a perspective view of a part of the device of Figure 1; Figure 5 is a section through a portion of a second embodiment of the invention; Figure 6 is an end view in the direction of arrow 6 of FigureS; and Figure 7 is a front partially cut-away view of a third embodiment of the invention.
Referring to the drawings, Figure lisa partial rear perspective view from above of the front casing 1 of a fire alarm terminal device. The front casing 1 is normally secured by for example screws in a wall-mounted rear casing (not shown). The front face of the casing defines a frame in which a sheet of glass is supported and retained by a clamp held in position by a pin 2. The actuating button of a switch (not shown) which is supported on the front casing bears against the sheet of glass so that the switch is actuated when the glass is broken or otherwise removed from its normal position relative to the front casing.
Figure 2 is a vertical section on the line 2-2 of Figure 1 and shows the top edge of a sheet of glass 3 which is retained in position by a clamp 4, which receives the head of pin 2. The pin 2 supports bars 5 and 6, bar 6 being inserted into the pin 2 after the pin has been pushed through an aperture 7 in the body of the casing 1.
Figure 3 is a view in the direction of arrow 3 in Figure 2 and shows the end of the pin 2 extending from the casing 1. The bar 5 is located above slots 8 in the aperture 7 so that the pin 2 may be slid out of the aperture until the bar 6 abuts against the rear face 9 of the casing 1.
Figure 4 is a perspective view of the pin 2, clamp 4 and bars 5 and 6. The force exerted on the glass by the switch actuating button (not shown) biases the clamp 4 away from the casing 1. In the position shown in Figures 2 and 3, the clamp 4 can move away from the casing as the bar 5 is aligned with the slots 8. Thus simply by pivoting the pin 2 about its axis to align the bar 5 and slots 8 one can release the pin 2 so that it moves outwards until further movement is prevented by the bar 6. As a result the glass moves out of its normal position and the switch is actuated.After this testing of the terminal device, a tool can be inserted in a socket 10 in the pin head, the pin can be pushed into the casing 1, thereby returning the clamp 4 and the glass 3 to its normal position, and the clamp can be secured in position by pivoting the pin 2 so that the bar 5 moves out of alignment with the slots 8. The bar 5 moves into contact with stops 11 that prevent overturning of the pin 2. When it is desired to test the device again, the pin 2 can be pivoted back until the bar 5 again abuts the stops 11, in which position the bar 5 is aligned with the slots 8. Thus a simple means is provided for rapidly and reliably testing the device by pivoting the pin 2 between a first position in which the clamp is retained and a second position in which the clamp is released.
Referring now to Figures 5 and 6, Figure 6 being a view on line 6 of Figure 5, an alternative structure for the pin 2 of Figures 1 to 4 is illustrated, the principle of operation being the same. The bars 5 and 6 of Figures 1 to 4 are replaced by integrally moulded lugs 12 and 13 respectively and the end of the pin which is resilient is split by a slot 14. In all other respects, except for minor dimensional variations the embodiments of Figures 1 to 4 and Figures 5 and 6 are the same. The slot 14 is provided in the end of the pin to enable the pin to be forced into the aperture in the front casing. The ends of the lugs 13 are tapered so that the end of the pin can be inserted easily into the casing. Thereafter the pin is forced home, the lugs 13 moving together as they pass through the casing and then snapping out once they clearthe casing.
Figure 7 shows a partly cut away front view of a fire alarm device illustrating a third embodiment of the present invention. A glass plate 15, which holds a spring load push button 16 of a switch (not shown) in a depressed position, is itself held in position by tabs 17 moulded onto the front casing 18 of a terminal device and a clamp 19 pivotally mounted on the front casing. The clamp 19 pivots about a pin 20 secured to the front casing and is biased to the position shown by a spring 21 acting on an actuating arm 22 integral with the clamp.
In the position shown, the end of the clamp 19 extends over the top edge of the glass plate and thus prevents the glass moving outwards under the influence of the spring loaded push button 16.
When it is desired to test the terminal device, a tool (not shown) in the form of a pin may be pushed through a hole 23 in the casing in the direction of arrow 24. The end of the pin pushes the arm 22 downwards against the spring 21, the clamp pivots and the glass falls forward, releasing the push button 16. After this testing of the device, the clamp is again pivoted, the glass is pushed back into position, and the clamp is released to retain the glass in position.
The abovedescribed testing procedures have assumed that once the switch has been actuated by removal of the glass it will become apparent that the device has operated satisfactorily, i.e. as the result of an audible alarm sounding. It may be however that an indication is required at the terminal itself that a satisfactory test result has been achieved. In addition, it is desirable to indicate at a terminal that the terminal is powered so that a failure in the supply will become immediately apparent. To this end, a light emitting device such as an LED may be connected between normally open contacts of the switch so that the light emitting device is energised whenever power is applied across these two terminals and is deenergised when the normally open contacts are closed during a test. This provides an indication at the terminal of energisation of the terminal and a satisfactory test result. To minimize power consumption and guard against overcurrent the light emitting device will be associated with appropriate circuitry, e.g. in the case of an LED a series resistor.

Claims (11)

1. An alarm terminal device comprising an electrical switch biased to a switch actuating position, a frangible member, means for supporting the frangible member in a predetermined position so as to restrain the actuating member from assuming the said actuating position, whereby the alarm device may be actuated by breaking the frangible member, and means for releasing the frangible member from said predetermined position to test the fire alarm terminal device, characterised in that the releasing means comprise means pivotal between a first position in which the frangible member is retained in said predetermined position and a second position in which the frangible member is free to move from said predetermined position.
2. An alarm terminal device according to claim 1, wherein the frangible member is retained in said predetermined position by a clamping member which is releasably secured in position by a pin which extends from the clamping member through an aperture in a portion of a casing of the fire alarm terminal device, the pin supporting at least one projection which in the said first position abuts against the rear surface of the said portion of the casing, preventing removal of the pin and thereby securing the clamping member in position, and in the said second position is able to pass through at least a portion of the aperture in the casing, enabling the pin to move axially to release the clamping member, the pin being movable between the first and second positions by pivoting about its own axis.
3. An alarm terminal device according to claim 2, wherein the pin extends through a bore in the clamping member, the pin being provided with an enlarged head which engages the clamping member.
4. An alarm terminal device according to claim 2 or 3, wherein the or each projection on the pin is a lug which in the said second position is movable through a slot running the length of the aperture in the casing through which the pin passes.
5. An alarm terminal device according to claim 2, 3 or 4, wherein the pin is extended beyond the said projection and at least one additional projection circumferentially offset from the other is provided towards the end of the pin, the additional projection preventing removal of the pin from the aperture when the pin is in the second position.
6. An alarm terminal device according to claim 5, wherein the end of the pin is made from a resilient material and formed with a slot between two said additional projections, whereby the pin may be inserted into the casing by forcing the additional projections together so that they may pass through the casing aperture.
7. An alarm terminal device according to claim 1, wherein the frangible member is retained in said predetermined position by a securing member held in said first position by resilient means and pivotal between said first and second positions by means of a lever portion of the securing member.
8. An alarm terminal device according to claim 7, wherein a hole is provided in the terminal device casing adjacent the lever, whereby the lever may be caused to pivot between said first and second positions by inserting a pin through the hole to push the lever.
9. An alarm terminal device according to any preceding claim, wherein means are provided to visually indicate the supply of power to the fire alarm terminal device, and to visually indicate actuation of the electrical switch.
10. An alarm terminal device according to claim 9, wherein the electrical switch comprises contacts which are open in the non-operating mode, and an LED and resistor are connected in series across the contacts.
11. An alarm terminal device substantially as hereinbefore described with reference to Figures 1 to 4, Figures 5 and 6, or Figure 7 of the accompanying drawings.
GB8107286A 1980-06-10 1981-03-09 Fire alarms Withdrawn GB2078004A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8107286A GB2078004A (en) 1980-06-10 1981-03-09 Fire alarms

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8018958 1980-06-10
GB8107286A GB2078004A (en) 1980-06-10 1981-03-09 Fire alarms

Publications (1)

Publication Number Publication Date
GB2078004A true GB2078004A (en) 1981-12-23

Family

ID=26275790

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8107286A Withdrawn GB2078004A (en) 1980-06-10 1981-03-09 Fire alarms

Country Status (1)

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GB (1) GB2078004A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0270286A2 (en) * 1986-11-20 1988-06-08 Signature Industries Limited Alarm switch
GB2247108A (en) * 1990-08-13 1992-02-19 Manher Amlani A signalling device
FR2835756A1 (en) * 2002-02-12 2003-08-15 Axendis Fire prevention fire alarm manual switch having sensitive element plate with mechanical elements setting off electrical circuit and drive unit distinct sensitive plate drive providing trial function.

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0270286A2 (en) * 1986-11-20 1988-06-08 Signature Industries Limited Alarm switch
EP0270286A3 (en) * 1986-11-20 1990-01-17 Clifford & Snell Limited Alarm switch
GB2247108A (en) * 1990-08-13 1992-02-19 Manher Amlani A signalling device
GB2247108B (en) * 1990-08-13 1995-01-11 Manher Amlani Signalling device
FR2835756A1 (en) * 2002-02-12 2003-08-15 Axendis Fire prevention fire alarm manual switch having sensitive element plate with mechanical elements setting off electrical circuit and drive unit distinct sensitive plate drive providing trial function.

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)