Head-lock fire sprinkler system

A fire sprinkler system and method comprising a plurality of water conduits having mounted thereon a plurality of sprinkler assembly receivers, and, removably coupled to the sprinkler assembly receivers, a plurality of bayonet-type quick release removable and locking sprinkler assemblies.

FIELD OF THE INVENTION 
This invention relates to fire sprinkler systems of the type that comprise 
a water distribution conduit system to which is mounted a plurality of 
sprinkler assemblies and, more particularly, to a quick-release fire 
sprinkler assembly and method therefor. 
BACKGROUND OF THE INVENTION 
Automatic fire sprinklers have been in use in the U.S. since 1874. Fire 
sprinklers are widely recognized as the single most effective method for 
fighting the spread of fires in their early stages--before they can cause 
severe injury to people and damage to property. When one fire sprinkler 
head is activated to fight a fire, the entire sprinkler system does not 
automatically activate. Instead, sprinklers react to temperatures in 
individual rooms. The chances of a fire sprinkler accidentally going off 
are extremely remote. 
More than 200 U.S. communities have residential sprinkler laws. In downtown 
Fresno for example, there has been fire damage of only $42,000 during a 
10-year period in which its sprinklering law has been in effect. According 
to the National Fire Protection Association, property damage in hotel 
fires was 78% less in structures with sprinklers than it was in structures 
without sprinklers during the years 1983-87. The average loss per fire was 
$2,300 in sprinklered buildings and $10,300 in unsprinklered buildings. 
Nearly half of all hotels and motels, according to a 1988 survey by NFPA, 
have sprinkler systems. 
Automatic sprinkler systems have enjoyed an enviable record of protecting 
life and property for more than 100 years. Water damage from a home 
sprinkler system will be much less severe than the damage caused by water 
from firefighting hose lines or smoke and fire damage if the fire goes 
unabated. Quick response sprinklers release 8-24 gallons of water per 
minute compared to 50-125 gallons per minute released by a fire hose. 
The sprinkler head portions of sprinkler assemblies are individually 
activated by fire. Residential fires are usually controlled with one 
sprinkler head. Ninety percent of all fires are controlled with six or 
fewer heads, and more than 80% of fires which occur are controlled by two 
or fewer sprinklers. Sprinklers provide a high level of life safety. 
Statistics demonstrate that there has never been any multiple loss of life 
in a fully sprinklered building. The combination of automatic sprinklers 
and early warning systems in all buildings and residences could reduce 
overall injuries, loss of life, and property damage by at least 50%. 
Periodically, it is necessary to change individual sprinkler heads or 
sprinkler assemblies in a fire sprinkler system. In most systems currently 
in use, each sprinkler assembly--comprising a base and head or nozzle--is 
screwed directly into the conduit or into a base member coupled to the 
conduit. In order to prevent leaking, plumber's tape or similar adhesive 
material is typically wrapped around the threaded base of the sprinkler 
assembly before insertion. This process can be time-consuming and 
labor-intensive. Moreover, during insertion of the assembly into the 
conduit or base member, a portion of the tape can break away and clog the 
assembly--limiting or preventing the flow of water from the conduit and 
out the sprinkler head. 
Some efforts have been made to improve this aspect of fire sprinkler 
systems. These efforts, however, have focused on the head or nozzle 
portion of the sprinkler assembly. For example, U.S. Pat. No. 4,185,781 
discloses a quick disconnect nozzle wherein a separate O-ring sealing 
member and a separate pressure applying spring are utilized. U.S. Pat. No. 
4,438,884 discloses a quick disconnect nozzle incorporating a tubular 
shaped combination seal and pressure exerting member. U.S. Pat. No. 
4,527,745 also discloses a quick disconnect nozzle assembly, which has 
particular applicability for agricultural uses, and which has camming 
surfaces adapted for drawing the mating nozzle tip and body parts together 
against an interposed sealing member in response to rotation of the nozzle 
tip, without the necessity for simultaneous manual axial forcing of the 
tip against the sealing member. U.S. Pat. No. 4,738,401 similarly features 
camming surfaces to draw the nozzle tip and body together while 
compressing a tubular configured sealing member with only rotational 
forces being applied to the tip. U.S. Pat. No. 5,415,348 also discloses a 
quick change and easily identifiable nozzle construction for use in 
modular sprinkler assembly. U.S. Pat. No. 5,333,790 to Christopher 
discloses a quick disconnect nozzle apparatus which allows any of a 
plurality of nozzles to be quickly secured to and removed from a fixed 
nozzle base, to meet the requirements of different types of aerial spray 
operations or provide different spray patterns. 
From the foregoing survey of the prior art, it will be apparent that while 
a great variety of quick release sprinkler heads or nozzles are known, 
each of these designs provides only for the quick release of the sprinkler 
head or nozzle--but not the sprinkler assembly as a whole. These prior art 
designs still provide sprinkler assemblies with grooved bases, which bases 
are inserted into a conduit. See, e.g., U.S. Pat. No. 5,415,348 (FIG. 1 
thereof); U.S. Pat. No. 5,333,790 (FIG. 2 thereof); U.S. Pat. No. 
5,190,224 (FIG. 1 thereof). Thus, none of these prior art designs provides 
a quick release assembly or base, and none of these eliminates the need 
for the use of sealing tape around the grooved base of the sprinkler 
assembly, so as to prevent fluid from leaking from the conduit. Moreover, 
these prior art designs are complicated and relatively expensive to 
construct. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a quick release fire sprinkler 
head that is economical and easy to use so as to provide a system which 
comprises a fire extinguisher water distribution system having a plurality 
of standard receptacles built into it and a plurality of quick release, 
interchangeable fire spray assemblies so as to permit the placement of an 
assembly having the desired spray characteristics for each location. 
It is an object of the present invention to provide an improved fire 
sprinkler system and method therefor. 
It is a further object of the present invention to provide an improved fire 
sprinkler system wherein an entire fire sprinkler apparatus, comprising a 
base and head or nozzle, may be quickly released from a receiver assembly 
attached to the surface of a conduit. 
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In accordance with one embodiment of the present invention, an improved 
fire sprinkler system is disclosed. The fire sprinkler system comprises, 
in combination: at least one water conduit; a plurality of openings in 
each conduit; a plurality of receiver means coupled to an outer surface 
portion of each conduit, each of the plurality of receiver means being in 
fluid communication with each conduit through one of the plurality of 
openings; means located in each of the receiver means for receiving in a 
quick-release manner a sprinkler assembly; a plurality of sprinkler 
assemblies; and means located on each of the sprinkler assemblies for 
releasably coupling in a quick release manner each of the sprinkler 
assemblies in fluid communication with each of the receiver means. 
In accordance with another embodiment of the present invention, a fire 
sprinkler system is disclosed. The fire sprinkler system comprises, in 
combination: a plurality of water conduits having passages through the 
walls thereof at predetermined points; a plurality of sprinkler assembly 
receivers mounted in the conduit system enclosing the wall passages; a 
multiplicity of sprinkler assemblies removably attached to the sprinkler 
assembly receivers for creating a spray or mist of water when the system 
is activated: the sprinkler assembly receivers being so constructed and 
configured as to form an interior passage defined by a cylindrical wall in 
fluid communication with the wall passages; the cylindrical wall having 
formed therein at least one bayonet type fastener slot having an entry 
portion generally parallel to the axis of the cylindrical wall and a 
locking portion generally perpendicular to the axis of the cylindrical 
wall; and the sprinkler assembly comprising: a cylindrical insert having a 
water passage axially formed therethrough in fluid communication with the 
wall passages; valve means closing the water passage to flow; means for 
forming a water spray or mist when the system is activated; a fusible link 
for opening the water passage to flow when the fusible link is heated to a 
predetermined temperature; and at least one bayonet pin extending from the 
cylindrical insert for beirg received in the bayonet slot in the 
receptacle wall for selectively locking the sprinkler head in the 
receptacle and, respectively, for permitting removal of the sprinkler head 
from the receptacle. 
In accordance with a further embodiment of the present invention, an 
improved method for replacing sprinkler assemblies is disclosed. The 
method comprises the steps of: providing at least one water conduit; 
providing a plurality of openings in each conduit; providing a plurality 
of receiver means coupled to an outer surface portion of each conduit, 
each of the plurality of receiver means being in fluid communication with 
each conduit through one of the plurality of openings; providing means 
located in each of the receiver means for receiving in a quick release 
manner a sprinkler assembly; providing a plurality of sprinkler 
assemblies; and providing means located on each of the sprinkler 
assemblies for releasably coupling in a quick release manner each of the 
sprinkler assemblies in fluid communication with each of the receiver 
means. 
In accordance with still a further embodiment of the present invention, an 
improved method for replacing sprinkler assemblies is disclosed. The 
method comprises the steps of: providing a plurality of water conduits 
having passages through the walls thereof at predetermined points; 
providing a plurality of sprinkler assembly receivers mounted in the 
conduit system enclosing the wall passages; providing a multiplicity of 
sprinkler assemblies removably attached to the sprinkler assembly 
receivers for creating a spray or mist of water when the system is 
activated; the sprinkler assembly receivers being so constructed and 
configured as to form an interior passage defined by a cylindrical wall in 
fluid communication with the wall passages; the cylindrical wall having 
formed therein at least one bayonet type fastener slot having an entry 
portion generally parallel to the axis of the cylindrical wall and a 
locking portion generally perpendicular to the axis of the cylindrical 
wall; and the sprinkler assembly comprising: a cylindrical insert having a 
water passage axially formed therethrough in fluid communication with the 
wall passages; valve means closing the water passage to flow; means for 
forming a water spray or mist when the system is activated; a fusible link 
for opening the water passage to flow when the fusible link is heated to a 
predetermined temperature; and at least one bayonet pin extending from the 
cylindrical insert for being received in the bayonet slot in the 
receptacle wall for selectively locking the sprinkler head in the 
receptacle and, respectively, for permitting removal of the sprinkler head 
from the receptacle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The drawing and the following description are of the preferred but not the 
only embodiment of the invention and, thus, are not limiting. The 
invention may be used with any of several spray and mist forming heads and 
the receptacles may be secured to or built into the system in any of 
several ways without departing from the invention. 
Referring to FIGS. 1-3, reference number 10 refers generally to the fire 
sprinkler system of this invention. The system 10 comprises conduits 12 
which typically have several segments defining, usually, a grid pattern. 
The system 10 further comprises a plurality of sprinkler assemblies 16 
comprising base and head or nozzle portions. Each sprinkler assembly 16 is 
received in a receiver assembly 18. 
The manner in which each sprinkler assembly 16 is received in a receiver 
assembly 18 is shown in FIG. 2. In this non-limiting example, a receiver 
assembly 18 comprises lower and upper saddle brackets 22 and 24 that are 
secured to the conduit 12 by a pair of bolt and nut assemblies, as 
depicted at 26 and 28 and at 30 and 32. A passage 34 through the wall of 
the conduit 12 permits water to flow to a cylindrical head receptacle 36 
of the receiver assembly 18, which is clamped to the conduit 12 by the 
saddle clamp assembly just described. Preferably two bayonet slots 38 are 
formed through opposing sides of the cylindrical head receptacle 36, and 
face in opposing directions. As is the nature of a bayonet slot and as 
also shown in FIG. 4, the slots 38 extend generally parallel to the axis 
of the cylindrical head receptacle 36 and then generally laterally 
thereof. 
Still referring to FIG. 2, a sprinkler assembly 16 is constructed and 
configured to be removably received in liquid sealing relationship in the 
head receptacle 36 and to be locked therein by means of the bayonet slots 
formed therein. The sprinkler assembly 16 comprises a cylindrical insert 
42 constructed and configured to receive sealing means such as O-rings 44 
and 46, and has, extending from an outer wall thereof, two bayonet pins 48 
configured to be received in the corresponding bayonet slots 38 in the 
head receptacle 36. When the bayonet pins 48 are received in the bayonet 
slots 38, they extend outside of the head receptacle 36, as shown in FIGS. 
1 and 3. In this manner, the sprinkler assembly 16 may be installed or 
removed with the use of a grasping tool (not shown), which tool may for 
example comprise a cylinder having an internal diameter greater than the 
external diameter of the sprinkler assembly 16 and bayonet slots 38 for 
gripping the bayonet pins 48. Use of such a tool, which is only made 
possible by having the bayonet pins 48 extend outside of the head 
receptacle 36, permits the installation and removal of the sprinkler 
assembly 16 with less strain on the bayonet pins 48 than if the sprinkler 
assembly 16 itself had to be grasped and turned for installation and 
removal. There is another advantage to having the bayonet pins 48 extend 
outside of the head receptacle 36. In this manner, a user can confirm 
whether the sprinkler assembly 16 has been properly installed simply by 
looking at the position of the bayonet pins 48 along the bayonet slots 
38--there is no need to grasp the sprinkler assembly 16 to determine if it 
has been properly secured into position. 
Referring now to FIG. 3, a housing 50 of the sprinkler assembly 16 is so 
constructed as to be connectable through a passage 52 extending through 
insert 42 and through the passage 34 for receiving water from the conduit 
12. The upper end of the passage 52 is closed by a valve member 54 held in 
fluid sealing relationship therewith by a fusible link 56 and a keeper 58. 
A spray or mist forming disk 60 is mounted at the distal end of the 
sprinkler assembly 16 by a screw 62, or other fastening means. 
The sprinkler assembly 16 is normally closed flow therethrough. When the 
temperature of the sprinkler assembly 16 reaches a predetermined point, 
the fusible link 56, which is made of a low-melting alloy or other low 
melting or low temperature softening material, melts or softens, thereby 
releasing the valve 54 thereby opening the passage 34. Water flows through 
the housing 50 and around the keeper 58 impinging through an opening in 
the distal end of housing 50 on the disk 60 and being dispersed as a spray 
or mist, according to the design of the disk. This mode of action, the use 
of a fusible link, etc., is standard in the industry. 
The O-rings 44 and 46 form a liquidtight seal between the sprinkler 
assembly 16 and the receiver assembly 18. Before water pressure is applied 
to the system 10, or during maintenance when no water is applied, the 
bayonet fastener arrangement permits quick and easy removal and 
replacement of the sprinkler assembly 16, as there is little frictional or 
other retaining force. When water pressure is applied, the force of the 
water pressure on the head locks the bayonet pins 48 in the bayonet slots 
38 making it nearly impossible to remove the sprinkler assembly 16 using 
normal human exerted forces. 
The system of this invention can be installed very economically and, at the 
same time, provides great flexibility in the placement of specifically 
designed sprinkler heads to maximize the fire suppression capability of 
the system. 
While the invention has been particularly shown and described with 
reference to preferred embodiments thereof, it will be understood by those 
skilled in the art that the foregoing and other changes in form and 
details may be made therein without departing from the spirit and scope of 
the invention. For example, it would be possible to construct the system 
10 of the present invention with only one bayonet slot 38 and only one 
corresponding bayonet pin 48, or to construct the bayonet slots 38 so that 
they are recessed into the interior of the head receptacle 36 rather than 
cut all of the way through the head receptacle. If constructed in this 
fashion, the bayonet pin 48 would lock into position in the same manner, 
but the bayonet pin would not extend beyond the head receptacle 36. 
INDUSTRIAL APPLICATION 
This invention is useful in the fire sprinkler industry.