US3884304A

US3884304A - Fire safety systems

Info

Publication number: US3884304A
Application number: US274817A
Authority: US
Inventors: Robert P Messerschmidt; Lloyd D Montag
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-07-24
Filing date: 1972-07-24
Publication date: 1975-05-20
Anticipated expiration: 1992-05-20

Abstract

Conventional water sprinkler heads, mounted in separate rooms, are set off by smoke detectors respectively mounted in the same rooms. A sprinkler head is set off by connecting a resistance wire coil across an electric potential. The heat generated melts the fusible link of the sprinkler head to discharge water therefrom. The coil is resilient to position it on the sprinkler head and is incorporated into a removable probe so that it may be replaced when desired. At a remote nurse''s station, a set of lights indicates system readiness and also when one or more sprinklers has been set off. Manually operated switches, at the nurse''s station, permit selected resistance coils to be energized to set off other sprinkler heads. A hallway smoke detector also provides an alarm at the nurse''s station to alert an attendant to the possible need for remotely actuating selected sprinkler heads or all sprinkler heads by closing a ''''gang'''' switch which is also provided.

Description

United States Patent i191 Messerschmidt et al.

[4 1 May 20, 1975 FIRE SAFETY SYSTEMS [76] Inventors: Robert P. Messerschmidt, 9390 Union Cemetary Rd., Loveland,

Ohio 45140; Lloyd D. Montag, 39 Millie Ave, Milford, Ohio 45150 [22] Filed: July 24, 1972 [2]] Appl. No.: 274,817

[52] US. Cl ..169/16, 169/42, 340/418 [51] Int. Cl. G08b 17/06; G08b 13/22 [58] Field of Search 340/418,222;169/1 B, 169/] R,20, 16, 37

[56] References Cited UNITED STATES PATENTS 725,827 4/1903 Cowles ..l69/37 2,728,904 12/1955 Schafer ..340/409 2,895,125 7/1959 Watts ..340/409 3,391,143 6/1964 Renda ..340/4l8 3,726,344 4/1973 Rathman ..169/37 Primary Examincr-Th0mas B. Habecker Attorney, Agent, or FirmEdmund S. Lee, III

[5 7] ABSTRACT Conventional water sprinkler heads, mounted in separate rooms, are set off by smoke detectors respectively mounted in the same rooms. A sprinkler head is set off by connecting a resistance wire: coil across an electric potential. The heat generated melts the fusible link of the sprinkler head to discharge water therefrom. The coil is resilient to position it on the sprinkler head and is incorporated into a removable probe so that it may be replaced when desired. At a remote nurse s station, a set of lights indicates system readiness and also when one or more sprinklers has been set off. Manually operated switches, at the nurses station, permit selected resistance coils to be energized to set off other sprinkler heads. A hallway smoke detector also provides an alarm at the nurses station to alert an attendant to the possible need for remotely actuating selected sprinkler heads or all sprinkler heads by closing a gang switch which is also provided.

29 Claims, 6 Drawing Figures 1 I 5 st Lmi PATENTED I 3,884,304 SHEET 2 OF 4 FEB E PATENTED W29l975 3,884,304

SHEET 3 OF 4 EM 4o Fusible Material 52 Bonded 53 54 l2\/-/ 54 44a 44b READY FIRE FIRE SAFETY SYSTEMS The present invention relates to improvements in fire safety systems.

Various types of fire safety systems have been developed and employed extensively for many years. One of the most widely used systems involves the provision of sprinkler heads mounted in the ceiling of a room. Such sprinkler heads comprise a fusible link which holds a valve closed under normal conditions. When a fire occurs, the fusible links are melted, allowing the valve to open and water is automatically discharged by the sprinkler heads to extinguish a fire which is presumably located beneath.

Another more recently developed fire safety system, is based on the use of smoke detectors. Such detectors sense an increase in the particulate concentration in the air, as would be caused by smoke from a fire. When a given smoke level is reached, an electrical signal is generated by the smoke detector which actuates an alarm system to alert the residents of a building or the like that a fire may be in progress.

While such systems have definite value, they do not provide the necessary level of fire safety which is desirable, if not absolutely necessary, in convalescent homes and other multi-unit residences for persons who may be ill or infirm.

The fusible elements employed with sprinkler heads have a relatively long response time. This is generally satisfactory in protecting a building or its inaminate contents from total distruction. However, it is possible for a heat rise, within such a long response time, to reach the point where a person could be seriously, or even mortally, burned. Different drawbacks are found in conventional smoke detector systems in that they are no more reliable than the ability of a person to react to the alarm they provide. Thus an infirm patient would have little or no ability to protect himself even if he heard the alarm. Even if an attendant were alerted by such an alarm, his ability to react could be seriously affected if a fire rapidly reached a roaring conflagration.

While the need and desirability for improved fire safety is most emphasized by the situation in convalescent homes, there are other circumstances where improvements are also desirable. For example, in private residences, hotels, motels, wharehouses, and the like, it is desirable that a fire safety system give maximum assurance that the entire building or a given area thereof will not reach a stage of conflagration endangering either occupants or contents.

Accordingly, one objective of the present invention is to provide an improved fire safety system for detecting the potential presence of a fire and actuating a sprinkler system before a state of conflagration is reached.

Another object of the invention is to provide an improved fire safety system providing a maximum of protection for patients in convalescent homes or the like.

Another object of the present invention is to attain the above ends in a manner economically compatible with existing fire protection systems.

Another object of the present invention is to provide a unique element for shortening the response time for actuation of sprinkler heads in fulfillment of the above ends.

In the broader aspects of the invention, these ends are attained by the combination of a sprinkler head, a

smoke detector, and means responsive to an output signal of the smoke detector for quickly melting the fusible element of the sprinkler head to automatically discharge water therefrom when a given rise in smoke density occurs.

In another aspect of the invention, means are pro vided for manually actuating means for quickly melting the fusible element of a sprinkler head, thereby discharging water therefrom prior to a fire reaching a stage of conflagration.

These features may be combined and employed in a multi-unit building, such as a convalescent home, with smoke detector and sprinkler head combinations in in dividual rooms. Means can be also provided, at a central location, such as an attendants station, to give an indication that one sprinkler head has discharged. This enables remote actuation of all of the remaining sprinkler heads or sprinkler heads in selected rooms by means provided for this purpose. Further, a smoke detector may be provided in a critical location, such as a hallway, to provide an alarm that remote actuation, at the attendants station of some, or all, of the sprinkler heads may be desirable.

More specifically, the fusible element melting means may take the form of an electrical resistance wire which is juxtapositioned relative to the fusible element, or link, of a conventional sprinkler head. This resistance wire is connected across an electrical potential, preferably of low voltage, which is sufficient to quickly generate a temperature which will melt the fusible element.

The electrical resistance is incorporated, as a separate article of manufacture, in a probe which is incor' porated in the electrical circuits actuated either by the smoke detector or the remote actuation means. Preferably, the resistance wire is in the form of a resilient coil which may be compressed between linkage elements of one type of sprinkler head to juxtaposition relative to the fusible element. It is also preferable that the resistance wire be coated with a low melting point dielectric material. This not only insulates the probe from the sprinkler head, but also provides a warning that sprinkler head is about to be discharged as the insulation is burnt off when current is passed therethrough to melt the fusible element. Additionally, the probe may be provided with means for positively positioning the resistance wire relative to the fusible element. These means may advantageously be formed as extensions of the dielectric material.

The electrical circuit may economically incorporate lights which indicate circuit continuity as well as actuation of a sprinkler head.

The above and other related objects and features of the invention will be apparent from a reading of the following description, with reference to the accompanying drawings, and the novelty thereof pointed out in the appended claims.

IN THE DRAWINGS:

FIG. 1 is a perspective view illustrating the installation of a tire safey system, embodying the present invention, in a convalescent home, or the like;

FIG. 2 is a view of a water sprinkler and associated heating element probe employed in the present invention;

FIG. 3 is aview similar to FIG. 2 illustrating actuation of the water sprinkler;

FIG. 4 is an enlarged view of the heating element probe employed in the present invention;

FIG. 5 is a perspective view of a control box employed herein; and

FIG. 6 is an electrical diagram of the circuit means employed in the present invention.

FIG. 1 is a schematic illustration of a portion of a building, such as a convalescent home, in which the present fire safety system may be incorporated. With more specific reference to a convalescent home, or the like, a two story building is illustrated showing an upper hallway h from which patient rooms may be entered from either side. Specifically rooms r,,, r,, and r,. are illustrated. From the upper hallway h, a stairway s leads to a lower foyer ffrom which other hallways may extend to other patients rooms. A receptionists desk, or nurses station, st is provided in the foyerf.

Water sprinkler heads 10 and associated heating element probes 12 are mounted on the ceiling of each of the patient rooms r r,, and r and are designated by corresponding subscripts. Further, within each of the rooms r r,, and r are mounted smoke detectors 14, again identified by corresponding subscripts. Mounted in the hallway h is a further smoke detector 1411.

As will later be described in greater detail, each sprinkler head 10 includes a fusible element which, when melted, releases a valve to permit discharge of water therefrom. Thus, if there should be a fire in any of the rooms, r,,, n, or r which generates sufficient heat to melt the fusible element, water will be discharged from that particular sprinkler into the room. This, is the conventional function of such sprinkler heads which is unaffected by the present invention.

Additionally, each smoke detector in a patient room is electrically connected, by the illustrated wiring, to the resistance probe within the room. When the smoke level in the room reaches a pre-determined level, an electrical signal generated by the smoke detector passes current through the electrical probe and causes the fusible element of the sprinkler to melt and discharge water into the room. Thus, the individual rooms are protected, both from an increase in smoke level, which would indicate a fire, or an incipient fire, as well as from an actual fire which generates, itself, enough heat to melt the fusible element. The above description, as well as that immediately following, is functional only and the actual electric current will later be described in detail.

The smoke detectors 14 are additionally connected, by the illustrated wiring, to control boxes 16 which are identified by corresponding subscripts, at the nurses station st. Each control box, see FIG. 5, includes a pair of

lights

18 and 20, which are preferably of different colors. The lights 18 indicate that the electrical system for the smoke detector is in a ready condition and capable of actuating the associated sprinkler head. The other light, 20, indicates a fire condition wherein the smoke detector has, in fact, actuated the associated electrical probe and sprinkler head. When a light 20 is lit, the nurse or attendant at station st is alerted to the fact that a fire or potential fire exists in a given room. An audible alarm could also be provided in addition to or as an alternative to the warning light 20. Dependant upon the circumstances at the time, the attendant could either check the room involved and/or immediately actuate the electrical probes and discharge water from the sprinklers 10 in adjacent rooms. This latter capability is provided by switches 22 which are provided in each of the control boxes 16. Closing of a switch 22 energizes the associated electrical probe to discharge water from the sprinkler head to which it is connected.

The hallway smoke detector 14h may be employed simply as an alarm device, being connected to a control box 16h at the nurses station st. The control box 16h, for such purposes would, comprise an alarm light 23 and a switch 25. The alarm light 23 would alert an attendant to either check the area involved or to immediately actuate all of the sprinkler heads 10 in the rooms r,,, r,, and r,. by closing switch 25. Alternatively, the hallway smoke detector l4h could also be connected to a resistance probe which would be associated with a hallway sprinkler and function in a fashion similar to the arrangement in the rooms r r,, and r,.

The detailed operation and features of the invention will now be described by next referencing FIG. 2. The sprinkler heads 10 may be of existing commercial design. In fact, one of the features of the invention is that it may be used with such existing sprinkler heads without modification thereof and thus may be readily incorporated into a building with an existing sprinkler system.

The sprinkler head 10, in FIG. 2, includes a casting having an upper nipple portion 24 which is threaded into a mounting plate 26. The mounting plate may be secured by screws 28 to a mounting bracket or other structural element forming a part of the rooms ceiling c. A short length of tubing 30 connects the nipple 24 to a T fitting 32 in a pressurized Water supply conduit 34. The sprinkler casting also comprises a bridle 34 which extends beneath the nipple outlet, as defined by a valve seat 36. In a state of readiness, discharge of water from the sprinkler head is prevented by a valve member 38 which is held in place by a pair of

lever arms

40 and 42 and a fusible link 44. The

lever arms

40 and 42 have aligned

conical tips

46 and 48 which respectively engage the valve 38 and the bridle 34. A knife edge engagement is provided between the

lever arms

40 and 42, at 50, in a slightly offset relationship from the aligned points of engagement of the

conical tips

46 and 48. This provides a leverage arrangement requiring only a very small force at the ends of the lever arms to maintain the valve 38 closed against a very substantial water pressure from the water conduit 34. The relatively small closing force may then be provided by the fusible link 44 even though the fusible material is relatively weak. The link 44, see also FIG. 4, comprises two plates, 44a and 44b, having a central offset. These plates may be formed of brass or the like and are joined by the fusible material. The links have a slot and opening in opposite ends, through which the

lever arms

40, 42 respectively pass. When a fire occurs, the fusible material melts and the links separate as the lever arms are forced apart and the valve 38 released by the force of the pressurized water. The fusible material is a low melting point eutectic which loses its strength relatively suddenly at a sharply defined temperature. While the response time for release of this link is relatively long, at temperatures close to the melting point of the fusible material, the release time is drastically reduced when the fusible material is subject to a much higher temperature.

The sprinkler head 10 and its fusible link 44 are merely illustrative. Other sprinkler constructions and fusible elements (not necessarily eutectic) therefor can be also employed, at least in the broader aspects of the invention.

Electrical resistance probe 12 is provided to generate a high temperature for melting the fusible link 44 in response to a signal from the associated smoke detector 14 or in response to manual closure of

switches

22 or 25 at the control box 16 at the nurses station st. Each electrical resistance probe 12, referencing also FIG. 4, comprises a coil 52 of nicrome wire or similar electrical resistance material commonly used in heating elements. This coil is disposed between the

lever arms

40 and 42 in close proximity to the fusible link 44. The coil 52 functions as a spring to resiliently maintain itself positioned between the

arms

40 and 42. The ends of the nicrome wire, forming the coil 52, are connected to insulated electrical leads 53. These connections, as well as the entire length of wire forming the coil 52, are sheathed within a flexible insulating material 54 such as plastisol, silicone rubber or suitable epoxy resin, having a relatively low melting point. The individual loops of the coil are thus insulated from each other and all con ductive portions of the probe are insulated from the metal elements of the sprinkler itself. The insulated leads 53 extend to a standard plug-in connector 58. Connector 58 is plugged into a jack 60 from which wires (not shown in FIG. 3) extend in a fashion more explicitly described in the electrical diagram of FIG. 5 and generally as indicated in FIG. 1. The probe 12 is thus a replaceable element. It can be economically replaced in the event it is energized or found defective for some reason.

Another feature to be noted is that insulating mate rial 54 is molded, at the opposite ends of the coil 52, to form gripping lugs 61 which embrace the

lever arms

40 and 42. The resilient spring action of the coil 52 holds it in place and the lugs 61 more positively position it relative to the link 44.

When a predetermined electrical potential is connected across the coil 52, heat is quickly generated to melt the fusible element 44, as evidenced by separation of the

plates

44a and 44b, and release the

arms

40 and 42. When this occurs, the

arms

40 and 42 are simply forced from the sprinkler, as water pressure displaces the valve 38 away from the end of the nipple 24 and water automatically is discharged therefrom, being spread over a substantial area by a baffle 62 secured to the bottom of the bridle 34. This condition is illustrated in FIG. 3 wherein it will also be seen that the water being sprayed from the sprinkler l0 splashes against the heated coil 52 to cool it down and provide assurance that the heated coil itself, will not become a fire hazard.

Another feature in the described arrangement is that when energizing current flows through the coil 52, the insulating material 54 is first burned or charred away, causing an unpleasant odor which would alert the person in the room that the sprinkler head was about to discharge. This feature could be employed in various ways. It can serve to alert a person who is mobile to im' mediately leave the room. It could also be visually ascertained that there is no immediate danger. In the latter event, an inactuation switch (not shown) could be employed to shut down the electrical circuit to the re sistance element and prevent unnecessary actuation of the sprinkler, or the same result could be attained by simply pulling the plug 58 from the jack 60.

Referencing next FIG. 6, the electrical circuit employed in the present invention is shown in greater detail. The smoke detectors 14 may be commercially available units, well known to those skilled in the art. Such detectors generate an electrical output signal when a predetermined level of smoke, or particulate concentration is sensed. In the present instance, this output signal is represented by a coil 64 which is energized to displace a contactor 66 and close a switch 67. Each of the switches 67 is connected to one side of a low voltage power supply 68 which may be physically located at the nurses station st.

The portions of the electrical circuit which include the

room smoke detectors

14a, 14b and each com prise a resistance probe 12 and alarm bulb 20 con nected in parallel and in series with switches 67, 22 and ready bulb 18 which are connected in parallel, all of which is connected across supply 68.

The portion of the electrical circuit which includes the hallway smoke detector 14h comprises the switch 67h connected in series with the area alarm bulb 23, across the power supply 68. Also associated therewith, in the control box 16h is the switch 23 which is a ganged switch connected from one side of the power supply, to provide a separate: series connection with each of the resistance probes 12.

With this arrangement, in the illustrated ready condition of the circuit, there is current flow through each of the ready bulbs 18, the alarm bulbs 20 and the resistance probes 12. At this point, it will be noted that the resistances of each pair of

bulbs

18, 20 is approximately equal and that the resistance of the bulb 18 is substantially greater than that of the probe coil 52. Thus, the greatest voltage drop will be across the bulb 18 and it will be brightly illuminated to indicate the ready condition. There will be a much lower drop across the coil 52 and the current flow therethrough will be insufficient to generate enough heat to either burn its insulating material or melt the fusible link. The current flow through bulb 20 will be insufficient to illuminate it. Should there be an open circuit to or through the probe 12, the

bulbs

18, 20 would both be illuminated to a reduced brilliance. This would indicate that servicing was required.

When one of the room smoke detectors 14a, b, or c, is actuated, its switch 67 is closed, say switch 67a. This completes a circuit, shorting out the bulb 18a, through the associated probe coil 52a. With the full potential of the power supply 68 connected thereacross, sufficient heat is generated to melt the fusible element in a desired, relatively short time period, say in the order of 15 seconds. At the same time, sufficient current flows through the bulb 20a to illuminate it and give a visual signal at the nurses station that the sprinkler in room r, is being set off.

At this time, there is an optional capability at the nurses station st, to either set off all sprinklers or sprinklers in selected rooms. To set off all sprinklers, switch 25 in control box 16h is closed. This connect all of the resistance probes directly across the power supply 68. To set offthe sprinkler in a given room, the appfpriate switch 22 is closed, connecting the probe for that room directly across the power supply.

While, as pointed out above, the smoke detetQ'r for the hallway be similarly connected to actuate a Efiii= kler head, in the present instance, it is used only 3E an alarm device. Thus, when switch 67h closes, bulb 25 i illuminated. The attendant at the nurses station can then make a decision as to what action should be taken and has the same options, as above, to immediately actuate all sprinklers by closing switch 25 or closing switches 24 for individual rooms, as desired.

One other feature of the circuit which provides additional protection is found in the provision of a fuse 70 in series with each of the coils 52. The fuses protect against the possibility of fire resulting from an overload through one of the circuits as a result of a short circuit 1 in a probe 12, particularly when a sprinkler head is discharged.

From the above description, it will be apparent that the present invention, particularly within its broader concepts, provides a great deal of flexibility which will 1 be apparent to those skilled in the art, and which will result in many modifications, particularly for specific applications, which depart from the preferred embodiment herein. For example, and not by way of limitation, a properly constructed fusible element could be incorporated in the electrical circuit and current passed therethrough to melt the element to set off a sprinkler head. Further dispensersfor fire suppressants other than water could be employed and in at least some aspects of the invention would be considered equivalent to a water sprinkler head. The spirit and scope of the present invention is therefor to be derived solely from the following claims.

Having thus described the invention, what is claimed as novel and desired to be secured by Letters Patent of 3 the United States is:

1. A fire safety system incorporated in an inhabitable structure having a plurality of rooms or areas, said system including a plurality of sprinkler heads respectively disposed in said rooms and areas, each sprinkler head being connected to a source of pressurized fire extinguishing fluid and comprising a valve and means, restrained by a fusible element, for holding the valve in a closed position preventing discharge of said fluid from the sprinkler head,

smoke detectors respectively disposed in said rooms and areas, each smoke detector comprising means for producing an output signal in response to a given rise in the density of smoke in the rooms and areas in which they are disposed,

resistance means, attachable mounted on said sprinkler heads, for melting the fusible element of 5 each sprinkler head to cause discharge of the fire extinguishing fluid therefrom,

means for automatically actuating each melting means in response to the output signal of a smoke detector adjacent thereto,

a control station remote from at least some of the rooms and areas in which the sprinkler heads are disposed,

an alarm, disposed at said control station, actuated in response to the output signal of one of said smoke detectors which is disposed in a critical room or area and is independent of the fusible element melting means,

separate alarms, disposed at said control station,

means, disposed at said control station, for manually and selectively actuating the fusible element melting means upon being alerted by said alarms, and

means, disposed at said control station and connected to each melting means, for indicating that the fusible element melting means are in a state of operativeness to be actuated by either the automatic or manual actuating means therefor.

2. A fire safety system as in claim 1 wherein the fusible element melting means comprise electrical resistance wires respectively juxtaposed relative to the fusible elements of the sprinkler heads and an electrical potential across which the resistance wires may be connected,

the means for automatically actuating the fusible element melting means include normally open switches, respectively connected in series with the resistance wires, which are closed to connect the respective resistance wires across said electrical potential,

the manual means for actuating the fusible element melting means comprise switches, disposed at said control station, respectively connected in parallel with said automatic switches the means for indicating that the fusible element melting means are in a state of operativeness, comprise ready light bulbs respectively connected in parallel with said switches,

the separate alarms comprise alarm light bulbs respectively connected in parallel across the resistance wires, and

the resistance of said ready light bulbs is substantially greater than that of the resistance wires and the resistance of the alarm light bulbs is at least approximately as great as that of said ready light bulbs.

3. A fire safety system incorporated in an inhabitable structure having a plurality of rooms or areas, said system including a plurality of sprinkler heads respectively disposed in said rooms and areas, each sprinkler being connected to a source of pressurized fire extinguishing fluid and including a valve, a pair of lever arms which have generally aligned portions for maintaining the valve in a closed position and generally parallel portions projecting outwardly, and a fusible element restraining said parallel portions from separation as the aligned portions maintain the valve in its closed position to prevent discharge of said fluid from the sprinkler head,

smoke detectors respectively disposed in said rooms and areas, each smoke detector comprising means for producing an output signal in response to a given rise in the density of smoke in the rooms and areas in which they are disposed, resistance element attachably mounted on the parallel portions ,of the lever arms of each sprinkler head in juxtaposition to the fusible element thereof, means for automatically connecting each resistance element across an electrical potential in response to the output signal of a smoke detector adjacent thereto, to melt the juxtaposed fusible element independently of the ambient temperature thereof and thus discharge fire extinguishing fluid from that sprinkler head,

an alarm, disposed at said control station, actuated in response to the output signal of one of said smoke detectors, and

means, disposed at said control station, for manually and selectively connecting said resistance elements across an electrical potential to melt the fusible elements juxtaposed thereto and discharge fire extinguishing fluid from sprinkler heads in selected rooms and areas.

4. A fire safety system comprising a sprinkler head connected to a source of pressurized fire extinguishing fluid and including a valve, a pair of lever arms which have generally aligned portions for maintaining the valve in a closed position and generally parallel portions projecting outwardly, and a fusible element restraining said parallel portions from separation as the aligned portions maintain the valve in its closed position to prevent discharge of said fluid from the sprinkler head,

a resistance element attachably mounted on the parallel portions of said lever arms in juxtaposition to said fusible element, and

means for connecting said resistance element across an electrical potential to melt said fusible element independently of the ambient temperature of the element and thus discharge fire extinguishing fluid from the sprinkler head.

'5. A fire safety system as in claim 4 wherein the resistance element comprises a resistance wire which is resiliently and axially deflectable and has a length greater than the distance between the parallel portions of the lever arms and further includes lugs, at opposite ends of the axial length of the resistance wire, for embracing the sides of the parallel portions of the lever arms,

whereby the resistance element may be juxtaposed relative to the fusible element of the sprinkler head by compressing the axial length of the resistance wire and positioning the lugs to embrace the sides of said parallel lever portions so that upon release the resistance element is securely held in place.

6. A fire safety system as in claim 4 wherein the resistance element is in the form of coiled, resistance wire, compression spring having an axial length greater than the distance between the parallel portions of the lever arms, which resistance wire spring, when compressed between the parallel lever arm portions is resiliently held in juxtaposition relative to the fusible element.

7. A fire safety system as in claim 6 wherein the resistance wire spring is sheathed within a flexible, low melting point, dielectric material which has integrally formed lugs at the opposite ends of the resistance wire spring, which lugs embrace the sides of the parallel lever arm portions to more securely position the resistance element thereon.

8. A fire safety system as in claim 4 which further includes a detachable electrical connector for incorporation into the means for connecting the resistance element across an electrical potential, and

insulated, flexible electrical leads connecting opposite ends of the resistance element to said connector, thereby forming a probe comprising the resistance" element, the connector and the connecting leads.

Claims

1. A fire safety system comprising: a water sprinkler head connected to a source of pressurized water, and including a valve and means, restrained by a fusible element, for holding said valve in a closed position preventing discharge of water from said sprinkler, a smoke detector including means for producing an output signal in response to a given rise in smoke density, means responsive to said output signal for generating heat sufficient to melt said fusible element, thereby releasing said valve and discharging water from said sprinkler.

2. A fire safety system as in claim 1 wherein the heat generating means comprise an electrical resistance wire juxtapositioned relative to said fusible element and means for connecting said electrical resistance element across an electrical potential sufficient to generate a predetermined heat level.

3. A fire safety system as in claim 1 further comprising manually operated means for independently actuating the heat generating means.

4. A fire safety system as in claim 1 wherein a plurality of said sprinkler heads are provided a plurality of said smoke detectors are provided, and additional means, responsive to the output signal of each additional smoke detector are provided for generating heat sufficient to melt the fusible element of a given sprinkler head thereby discharging water from said sprinkler head.

5. A fire safety system as in claim 4 further comprising manually operated means for separately activating selected heat generating means and manually operated means for manually actuating all of said heat generating means.

6. A fire safety system as in claim 5 wherein each of the heat generating means comprise an electrical resistance wire juxtapositioned relative to each of fusible element and means for connecting said electrical resistance element across an electrical potential sufficient to generate a predetermined heat level.

7. A fire safety system as in claim 6 in combination with a building comprising a plurality of rooms and a common area and further wherein a smoke detector and a water sprinkler head combination are respectively mounted in separate rooms thereof, the resistance element of the water sprinkler in one room is connected across the electrical potential in response to the output signal of the smoke detector in that room, and further comprising a further said smoke detector mounted in said common area and means, responsive to said further smoke detector, for providing an alarm for alerting an attendant as to the possible need for operating said manually operated means.

8. A fire safety system as in claim 7 wherein the manually operated means and the means for providing an alarm are disposed in a common, remote location.

9. A fire safety system as in claim 4 in combination with a building comprising a plurality of rooms and further wherein a smoke detector and water sprinkler head combination are respectively mounted in separate rooms thereof.

10. A fire safety system as in claim 9 wherein each of the heat generating means comprise electrical resistance wires respectively juxapositioned relative to the fusible elements of each sprinkler head and an electrical potential across which said resistance wires are adapted to be connected, and the means responsive to the output signal of a smoke detector in a room connect the resistance element of the water sprinkler in that room across the electrical potential.

11. A fire safety system as in claim 10 wherein the means responsive to said smoke detectors include normally open switches respectively connected in series with said resistance wires across the electrical potential.

12. A fire safety system as in claim 11 wherein ''''ready'''' light bulbs are respectively connected in parallel across said switches and ''''alarm'''' light bulbs are connected in parallel with said resistance wire and further wherein, the resistance of said ''''ready'''' light bulbs is substantially greater than the resistance of said resistance wires and further wherein the resistance of the ''''alarm'''' light bulbs is at least approximately as great as that of said ''''ready'''' light bulbs.

13. A fire safety system as in claim 12 wherein said light bulbs are mounted at a common, remote station and further wherein manually operable switches are respectively mounted in parallel with the parallel connected ''''ready'''' light bulbs and switches, said manually operated switches also being mounted at said common, remote stations.

14. A fire safety system as in claim 13 wherein a hallway, or the like, is adjacent said separate rooms and a further, said smoke detector is mounted in said hallway means responsive to the output signal of said hallway smoke detector provide an alarm signal at said common, remote station and a normally open, manually operable switch adjacent said hallway alarm is connected in series with a plurality of said resistance wires, across said electrical potential, whereby all of said resistance wires can be connected across said electrical potential in response to the hallway alarm.

15. A fire safety system as in claim 10 wherein each resistance wire is incorporated into a probe removably connected into the electrical connections therefor.

16. A fire safety system as in claim 15 wherein the resistance wire is in the form of a resilient coil and is covered with insulation material.

17. A fire safety system as in claim 16 wherein each sprinkler head has opposed arms adjacent the fusible element thereof and positioning means are provided at the opposite ends of said coil to hold said coil in juxtaposition with said fusible element.

18. A fire safety system as in claim 2 wherein the electrical resistance wire is incorporated into a probe removably connected with the means connecting the resistance wire across the electrical potential.

19. A fire safety system as in claim 2 wherein the electrical resistance wire is in the form of a resilient coil and is covered with flexible, low melting point dielectric material.

20. A fire safety system as in claim 19 wherein said electrical resistance probe includes means for positioning said coil in juxtaposition with said fusible element.

21. A probe for use in a fire safety system, said probe comprising an electrical resistance wire adapted to be juxtapositioned relative to a fusible element which is to be melted to set off a sprinkler head, and electrical leads connected to the opposite ends of said coil and removably connectable into an electrical circuit for passing current through the resistance wire to generate heat sufficient to quickly melt the fusible element.

22. A probe as in claim 21 wherein the electrical resistance wire is in the form of a resilient coil.

23. A probe as in claim 22 wherein the electrical resistance wire, including the coil, is covered with a flexible, low melting point dielectric material having a distinctive odor when heated to an elevated temperature.

24. A probe as in claim 23 wherein the probe includes means for gripping the water sprinkler head and position the resistance wire coil in juxtaposition to the fusible element thereof.

25. A probe as in claim 24 wherein the gripping means are integrally formed of said insulating dielectric material and comprise lugs at the opposite ends of said coil.

26. A fire safety system comprising a water sprinkler head connected to a source of pressurized water, and including a valve and means, restrained by a fusible element, for holding said valve in a closed position preventing discharge of water from said sprinkler, and electrical resistance means for generating heat suffIcient to melt said fusible element, thereby releasing said valve and discharging water from said sprinkler.

27. A fire safety system as in claim 25 wherein the heat generating means comprise an electrical resistance wire juxtapositioned relative to said fusible element and manually operable means are provided for connecting said electrical resistance element across an electrical potential sufficient to generate a predetermined heat level.

28. A fire safety system as in claim 27 wherein the electrical resistance wire is in the form of a resilient coil and is covered with a flexible, low melting point dielectrical material.

29. A fire safety system as in claim 28 wherein the electrical resistance wire is incorporated into a probe removably connected with the electrical connections to said electrical potential.