Fire protection sprinkler head with spaced zones for mounting a protective guard and for connecting the sprinkler head to a water supply line
BACKGROUND OF THE INVENTION 
     Sprinkler heads that depend from low ceilings or those mounted in storage racks in industrial or commercial establishments frequently include a wire-form protective guard, which prevents accidental damage to the thermally responsive element, such as a glass bulb or fusible element. 
     In a typical installation, each sprinkler head is connected to the water system by threading the sprinkler head to the water line through use of a special wrench or tool that engages a polygonal-shaped ridge or groove on the body of the sprinkler head. After installation of the sprinkler head, the wire guard is then installed on the sprinkler head. The wire guard is typically connected to the sprinkler head by engaging the base of the guard with the wrench groove, and the guard is then locked to the body by fasteners such as screws, or other fastening means. 
     The installation of the protective guards is very time consuming and labor intensive. Such labor intensity and time consumption may be amplified by the common practice of installing all of the sprinkler heads first and then returning later to each sprinkler location to install the wire form guard in a second operation. Each wire guard is composed of two or more components, and the workman is normally working in an awkward overhead position, or in the case of storage racks, in relatively inaccessible locations. As a storage rack in an industrial or commercial establishment may contain thousands of sprinkler heads, the installation of the protective guards constitutes a time consuming process which comprises a substantial portion of the overall cost of the sprinkler system. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a sprinkler head having a pre-assembled wire guard which will not interfere with the normal installation of the sprinkler head with the water line. 
     The sprinkler head includes a tubular body, one end of which is threaded to a water line, while the opposite end defines an outlet that is normally enclosed by a cap or closure. 
     In the preferred form of the sprinkler head, the body also includes a pair of arms which are joined together at a junction, and a thermally responsive member, such as a glass bulb or fusible element, is connected between the junction and the cap, thus retaining the cap in a closed position. When the thermally responsive member is exposed to an elevated temperature, it will release, enabling the pressure of the water in the water line to dislodge the cap and the water will then be discharged into the building or other establishment in a conventional manner. 
     In accordance with the invention, the body of the sprinkler head is provided with a pair of circumferentially extending zones which preferably take the form of external grooves. The bottom of the groove which is located adjacent the threaded end of the body is provided with a polygonal configuration, preferably hexagonal, and is adapted to receive a wrench or tool. Engagement of the tool with the groove enables the sprinkler head to be rotated to thread the sprinkler head to the water line. 
     The base of a wire-form protective guard is secured within the second of the two grooves. The guard itself can be of conventional construction and includes a mechanism for locking the base portion within the second groove. 
     With the invention, the guard is preassembled with the sprinkler head at the factory, and as the wire guard does not restrict access to the wrench groove, the guard can be retained in place while the sprinkler head is attached to the water line. This results in a substantial savings in time and labor, due to the fact that it is not necessary to install the protective guard after installation of the sprinkler head to the water line. This provides a substantial overall cost saving in the sprinkler system. 
     Moreover, as the guard is attached to the sprinkler head at the factory, it will protect the thermally responsive element during shipment and handling of the sprinkler head. 
     Other objects and advantages will appear during the course of the following description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings illustrate the best mode presently contemplated of carrying out the invention. 
     In the drawings: 
     FIG. 1 is a side elevation of the sprinkler head of the invention; 
     FIG. 2 is an exploded view of the wire-form guard, with the sprinkler head removed; 
     FIG. 3 is a section taken along line 3--3 of FIG. 1; and 
     FIG. 4 is an enlarged fragmentary side elevation illustrating the locking mechanism for the wire guard, with reference to detail 4 of FIG. 1. 
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
     FIG. 1 illustrates a sprinkler head including a body or frame 1 having an external thread 2 that is adapted to be connected to a water line. The opposite end of the tubular body 1 defines an outlet 3 which is normally sealed by a cap or closure 4. 
     Body 1 also includes a pair of depending arms 5 and the outer ends of the arms are joined at a junction 6. As shown in FIG. 1, a thermally responsive member 7 interconnects the cap 4 and an adjusting screw 8 which is threaded within an opening in the junction 6. 
     The thermally responsive member can take the form of a conventional glass bulb or alternately a fusible element. When the thermally responsive member is exposed to an elevated temperature, it will release, enabling the water pressure within the water line to dislodge cap 4. The water will then flow outwardly through outlet 3 and be deflected radially outward in a spray pattern by a deflector 9, which is carried by the junction 6. 
     A wrench boss or groove 10 is formed in body 1 outward of the thread 2, and the bottom 11 of groove 10 has a non-circular, polygonal shape, preferably hexagonal. In addition to groove 10, a second circumferential groove 12 is formed outwardly of groove 10 and the bottom of groove 12 also can have a non-circular or polygonal configuration, such as hexagonal. 
     Groove 10 serves to receive a conventional wrench or tool through which the sprinkler head can be threaded onto the water line, while groove 12 receives a water permeable wire form protective guard 14. 
     As shown in FIG. 2, guard 14 includes a pair of generally parallel base members 15, each of which is formed with a recess 16 which is adapted to engage opposite sides of the bottom of groove 12. 
     A series of wire arms 17 are each provided with a bent foot 18, and each foot is attached to the respective base members 15. The outer ends of arms 17 are bent radially inward as indicated by 19, and are joined together at a junction 20. 
     To lock the guard to the body 1, a locking ring 21 is employed. By sliding the ring 21 inwardly over the arms 17, the arms will be deflected inwardly to bring the base members 15 into tight engagement with groove 12. Locking ring 21 is secured in position by engagement with detents or notches 22 formed in the arms 17. 
     When locked in position, guard 14 surrounds the thermally responsive member 7 and serves to protect that member during shipment, storage, and usage. 
     With the use of the double parallel grooves, the guard 14 can be installed at the factory by engaging the base members 15 with the groove 12. The second wrench groove 10 is accessible when the guard 14 is in place so that the sprinkler head can be threaded to the water line without removal of the guard. 
     The invention thus eliminates the conventional task of having to install the guard 14 after the sprinkler head is attached to the water line. 
     As previously noted, the task of connecting the protective guard, as required in the past, was time consuming, because the guard is normally composed of multiple components and the operator is required to work in an awkward overhead position, or in a relatively inaccessible location when dealing with storage racks, in order to install the guard. 
     As the guard, as associated with the sprinkler head of the invention, is installed at the factory, it also serves to protect the thermally responsive member from damage during shipment and handling.