turning now to the drawings in which like reference characters indicate corresponding elements throughout the several views , attention is first directed to fig1 which shows the nozzle according to the present invention , indicated in its entirety by the numeral 10 , being manipulated by a firefighter 12 . with further reference to fig2 and 3 , the nozzle 10 comprises a generally cylindrical nozzle body or outer housing 14 having an inlet end 16 secured by a swivel coupling 18 to a conventional fire hose 20 . the outlet end 22 of the nozzle body 14 defines a central jet orifice 24 for discharging a circular , solid stream 26 of liquid . the jet orifice 24 is concentrically surrounded by an annular fog spray opening 28 for discharging a conical spray or fog 30 , made up of liquid droplets which are evenly distributed throughout the cone . the droplets are produced by a plurality of inwardly curved , forwardly projecting teeth 32 formed along the circumference of the fog spray opening 28 . a shaper ring 33 is moveably mounted at the outlet end 22 of the nozzle body 14 , for allowing adjustment of the included angle of the fog cone 30 . a specially configured gripping assembly 34 is provided on the underside of the nozzle body 14 . the gripping assembly 34 includes an upper support bar 36 , a rear pistol grip 38 having a manually actuable trigger 40 , and a front grip 42 having a twist actuator 43 with a knurled outer surface . a lower guard bar 45 extends between rear grip 38 and front grip 42 , preventing the hose 20 or other object from becoming entangled in the gripping assembly and accidentally depressing the trigger 40 . the function and structure of trigger 40 and twist actuator 43 will be described shortly . turning now to fig4 a jet control valve 44 is provided for controlling the discharge of liquid through the jet orifice 24 . specifically , the jet control valve 44 allows the diameter of the circular solid stream 26 to be selectively varied in addition , a fog control valve 46 is provided for controlling the discharge of liquid through the annular fog spray opening 28 . the jet control valve 44 and fog control valve 46 are operable both simultaneously with and independently of one another . the structure and operation of the jet control valve 44 can be best understood by referring to fig5 - 9 . as can be seen most clearly in fig9 the jet control valve 44 includes an interior valve housing 48 , which is located in spaced relationship to the inner sidewall of the outer housing 14 by a plurality of radially extending straightening vanes 50 . for ease of manufacturing , the interior valve housing 48 is preferably constructed as a three - piece body , including a generally tubular front member 52 having an open front end 54 and an internally threaded , open back end 56 ; a rear member 57 having an internally threaded open , front end 58 and a closed back end 60 ; and a generally tubular , central connector member 62 having both ends externally threaded for cooperation with the corresponding internally threaded ends of the front and rear members 56 , 57 . a sleeve bearing 64 is carried in the bore of the connector member 62 . with additional reference to fig5 the interior valve housing 48 defines a hydraulic chamber 66 , consisting of a front chamber 68 carried in the front member 52 and a rear chamber 70 carried in the rear member 57 . a plurality of circumferentially spaced apart , meshed covered openings 71 formed in the sidewall of the rear member 67 serve as inlets for admitting filtered liquid into the rear chamber 70 . an outlet passage 72 extending through the sidewall of the front member 52 discharges liquid from the front chamber 68 . the bore 73 of the sleeve bearing 64 defines a flow passage connecting the two chambers 68 , 70 . a valve body 74 having a forwardly tapered front end 76 is mounted for longitudinal translation within the hydraulic chamber 66 . a sealing ring 78 carried on an intermediate portion of the valve body 74 prevents liquid in the hydraulic chamber 66 from escaping past the front end 76 . in addition , the valve body 74 includes an elongated tail portion 80 which extends rearwardly through the sleeve bearing 64 . a plurality of longitudinally extending grooves 82 are machined or otherwise formed in the tail portion 80 . the depth of the grooves 82 increases toward the front of tail portion 80 . an annular valve seat 84 is formed forwardly of the valve body 74 . the valve seat 84 is formed along the rear inner surface of a specially configured tip assembly 86 , which will be described in greater detail shortly , in connection with the fog control valve 46 . the surface of the valve seat 84 is preferably tapered or contoured to match the taper or contour of the base portion 88 of the conical front end 76 of the valve body 74 , so that a tight seal is formed when the valve body 74 is in its full forward position , as shown in fig6 . the movement of the valve body 74 relative to the valve seat 84 is controlled by varying the pressure in the front chamber 68 of the hydraulic chamber 66 . this pressure is controlled by a needle - type metering valve 90 , which is mounted for longitudinal reciprocation in a control passage 92 communicating with the outlet passage 72 from the front chamber 66 . the control passage 92 comprises a chamber formed in the upper support bar 36 of the nozzle grip assembly 34 , extending perpendicular to the outlet passage 72 . the needle valve 90 includes a suitably shaped front end 94 , the base 96 of which resides against an annular valve seat 98 at the forward end of the control passage 92 , when the valve 90 is in its fully forward position . as the valve 90 moves back , away from the valve seat 98 , liquid in the control passage 92 is allowed to escape past the front end 94 of the needle valve 90 , into a relief duct 100 extending longitudinally through the support bar 36 . liquid in the relief duct 100 exits as a forwardly directed stream through an outlet 102 formed in the front end of the support bar 36 . the needle valve 90 is mechanically coupled to a trigger 40 moveably mounted in the rear grip 38 . the trigger 104 is biased to a full forward position by a spring 106 having one end secured to the grip 38 and another end carried in a cavity 108 formed in the trigger 40 . thus , the trigger automatically returns to the forward position when released , forcing the needle valve 90 against the valve seat 98 , and shutting off the flow from the jet stream orifice 24 . this is an important safety feature , since the high reaction forces generated by the jet stream could cause the hose 20 to whip around dangerously , injuring firefighters , if the jet stream valve 44 were to remain open if the nozzle 10 was dropped . fig5 illustrates the flow of liquid through the nozzle 10 when the trigger 40 is in its completely retracted position , fully opening needle valve 90 and jet control valve 44 . pressurized liquid enters through the inlet end 16 of the nozzle 10 and flows around the interior valve housing 48 and past the straightening vanes 50 , as indicated by arrows a . the liquid then enters the tip assembly 86 through a smooth - walled flow passage 112 which continuously diminishes in area in the forward direction , slowly accelerating the flow to produce a more stable liquid jet . from the flow passages 112 , some of the liquid enters an outlet tube 114 . the flow passages 112 form a sharp corner 116 with the outlet tube 114 , allowing the liquid to make a &# 34 ; clean break &# 34 ;. any liquid not entering the outlet tube 114 flows into the fog spray opening 28 via a plurality of circumferentially spaced apart openings 117 formed in the wall of the flow passage 112 , as will be described shortly . in addition to the liquid flowing around the interior housing 48 , a small amount of liquid enters the hydraulic chamber 66 through openings 71 in the rear chamber 70 , as shown by arrows b . the liquid travels from rear chamber 70 to the front chamber 68 via the grooves 82 in the tail portion 80 of the valve body 74 , which allow maximum flow through the sleeve bearing 64 when the valve body 74 is fully aft . from the front chamber 68 , the liquid enters the outlet passage 72 , passes around the front end 94 of the shaped needle valve 90 into the relief duct 100 , finally exiting through the outlet 102 . because of the continuous discharge of liquid through the outlet passage 72 and relief duct 102 , the pressure in the hydraulic chamber 66 is always minimum , allowing the jet control valve body 74 to remain fully aft until the trigger 40 is released . fig6 illustrates the valve configuration when the trigger 40 is released , closing the needle valve 90 and the jet control valve 44 . in this configuration , the needle valve 90 resides against the valve seat 98 , shutting off the flow from the outlet passage 72 to the relief duct 100 . as a result , the pressure in the front chamber 68 of the hydraulic chamber increases , forcing the valve body 74 forwardly until the base portion of the tapered front end 76 sealingly engages the valve seat 84 , cutting off flow to the outlet tube 114 . in addition , when the valve body 74 is in its fully forward position , the rear end 118 of the tail 80 allows minimum leakage into the hydraulic chamber , maintaining the valve body 74 in its forward position . although not specifically illustrated , it will be clear to the skilled practitioner that the trigger 40 may be held in any position intermediate the two extremes shown in fig5 and 6 . as the trigger 40 is retracted , the valve body 74 moves away from the valve seat 84 by an amount proportional to the pull on the trigger , thus increasing the area between the front end 76 of the valve and the valve seat 84 , resulting in a jet of greater diameter . since the reaction force generated by the stream varies in proportion to its size for a given pressure , the nozzle operator is able to simply and quickly adjust this force to its safest , most effective level merely by varying the pull on the trigger . flow downstream of the jet control valve 44 may be best understood by referring to fig1 , which shows the components of the tip assembly 86 , and also to the longitudinal cross - sections in fig4 and 10 . the tip assembly 86 includes a generally cylindrical main body 120 having an externally threaded rear end 122 for attachment to the front end of the nozzle body 14 . a radially extending flange 124 separates threaded end 122 from a second externally threaded portion 126 , on which an internally threaded housing nut 128 is mounted . the outer diameter of the main body 120 is reduced forwardly of the threaded portion 126 to form a boss 130 . a hydraulic chamber 132 is defined between the boss 130 and the inner surface of the housing nut 128 . the outer diameter of the main body 120 is reduced still further forwardly of the boss 130 , forming outlet tube 114 . the front end of the boss 130 extends perpendicularly to the outlet tube 114 , forming an annular end wall 134 . a plurality of bores or openings 117 extend longitudinally from the annular end wall 134 to the rear inner surface of the main body 120 , where they intersect with the flow passages 112 described earlier , in connection with fig5 . the outer surface of the outlet tube 114 is stepped slightly inwardly at a location halfway between annular wall 134 and the outlet end 22 to form a reduced diameter front portion 138 on which a spacer ring 140 is mounted . the spacer ring 140 comprises an annular body 142 having a flange 144 extending radially outwardly from its forward end . a plurality of positioning vanes 146 extend radially outwardly from and longitudinally along the annular body 142 . the spacer ring 140 is clamped against the step 148 in the outlet tube 114 by a split retaining ring 150 carried in a groove 152 formed at the outlet end 22 of the tube 114 . an o - ring 153 is interposed between the spacer ring 140 and the retaining ring 150 . an annular valve body 154 is supported by the positioning vanes 146 , and mounted for longitudinal movement along the outer surface of the outlet tube 114 . the space between the valve body 154 and the outlet tube 114 defines the annular fog spray opening 28 . the front end of the valve body 154 comprises a tapered surface 156 which terminates in forwardly projecting teeth 32 . the rear end of the valve body 154 includes an inwardly projecting flange 158 which extends into the hydraulic chamber 132 . when the valve body 154 is in its fully forward position , as shown in fig1 , the bottom edge of the flange 158 engages the outer surface of the boss 130 , minimizing flow between the fog spray opening 20 and the hydraulic chamber 132 . at the same time , the tapered front surface 156 of the valve body engages the rear outer surface of the spacer ring 140 , which functions as a valve seat 160 . together , the annular valve body 154 and the valve seat 160 are the primary components of the fog control valve 46 . the operation of the fog control valve 46 is generally similar to the operation of the jet control valve 44 . that is , the movement of the valve body 154 is controlled by varying the pressure in the hydraulic chamber 132 . the pressure in the chamber 132 is controlled by a metering valve 162 mounted in a control passage 164 formed in the front grip 42 of the grip assembly 34 . the control passage 164 communicates with both an outlet passage 166 extending from the hydraulic chamber 132 and a bleed passage 168 extending through the front grip 42 and the upper support bar 36 . the bleed passage 168 terminates in an outlet 170 , which allows water to exit as a forwardly directed stream . in contrast to the needle valve 90 governing the jet control valve 44 , which is mounted solely for longitudinal movement , the metering valve 162 for the fog valve 46 is rotatably mounted , and is retained within the front grip 42 by screw threads 172 . the valve 162 is secured by set screws 174 to a twist actuator 43 mounted for rotation about the front grip 42 . the screw threads 172 convert the twisting movement of the actuator to a longitudinal movement of the metering valve 162 toward or away from its seat 178 . in addition , the screw threads 172 retain the valve 172 in its most recent position when the actuator 43 is released . thus , the control valve 46 can be remain open even when the nozzle 10 is dropped , so that the protective , cooling effects of the fog spray are not lost . operation of the fog control valve 46 may be understood by referring to fig1 and 11 . when the valve is fully closed , as shown in fig1 , liquid entering the annular flow opening 28 through the bores 117 in the tip assembly 86 exerts a rearward pressure on the rear flange 158 of the valve body 154 . this pressure is counteracted by forward pressure in the hydraulic chamber 132 , causing the valve 46 to remain closed . however , as soon as the twist actuator 43 is rotated , causing the metering valve 162 to move away from its seat 178 , the pressure in the hydraulic chamber 132 decreases , allowing the valve body 154 to move rearwardly . as the valve body 154 moves rearwardly , its rear flange 158 passes over a groove 180 formed in the front end of the boss 130 projecting from the main body 120 . the clearance between the bottom edge of the flange 158 and the bottom wall of the groove 180 allows more liquid to flow into the hydraulic chamber 132 , and then out again through the outlet passage 166 and bleed passage 168 . at the same time , the tapered front surface 156 of the valve body 154 moves away from the valve seat 160 allowing liquid to exit from the fog orifice 28 . fluid exiting through the orifice 28 impinges on the forwardly directed teeth 32 , which direct the flow in all directions , creating a conical &# 34 ; fog &# 34 ; 30 of evenly distributed droplets . the included angle of the fog cone 30 may be selectively varied by manipulation of the shaper ring 33 , which consists of an annular member having an inwardly extending flange 182 formed at its rear end . the flange 182 is disposed for sliding movement in a recess extending annularly around the valve body 154 . although not specifically illustrated , a control ring or lever may be provided on the shaper ring for allowing manual control of the shaper ring &# 39 ; s movement . such a ring or lever preferably depends from the underside of the shaper ring 33 and is readily accessible from the front grip 42 , so that an operator can grasp it with a thumb or other finger , without removing his hand from the twist actuator 174 . fig1 shows the shaper ring 33 in its fully aft position , which results in the widest possible fog cone angle fig1 shows the shaper ring 33 in its fully forward position . in this position , the front end of the ring 33 projects forwardly , beyond the valve seat 160 and the front end 22 of the nozzle , thus forming a ceiling which narrows the fog cone to its minimum included angle . other than this , the flow of liquid in fig1 is exactly the same as in fig1 . the shaper ring 33 is mounted on the valve body 154 in such a way that the reaction forces created by the exiting liquid automatically force the ring 33 to the fully aft position shown fig1 when the control lever is released , since the widest angle cone is safest . although fig1 - 12 show the fog valve 46 only in its fully open and fully closed position , and the shaper ring 33 fully forward and fully aft , it will be evident that both the fog valve 46 and the shaper ring 33 can be independently maintained in any position intermediate these extremes . it will also be evident that , although fig1 - 12 show the jet control valve 44 fully closed , the fog control valve 46 and shaper ring 33 can also be operated when the jet control valve 44 is fully open , or in an intermediate position . the state of the fog control valve 46 is not in any way dependent on the state of the jet control valve , and vice versa . thus , an infinitely variable combination of discharge patterns is obtainable . a modification of the actuator for the jet control valve 44 is illustrated in fig1 . the operating principles behind the modified actuator 186 are the same as in the actuator of fig5 except that the needle valve 188 and its control chamber 190 are coaxial with , rather than perpendicular to , the outlet passage 72 , and the trigger 192 is mounted for pivoting movement in the rear grip 38 . in addition , the relief duct 194 extends longitudinally through the bottom guard bar 44 , rather than the top support bar 36 . as in previous embodiment , however , the needle valve 188 is biased by a spring 196 toward the closed position , so that the jet valve closes automatically when the trigger 192 is released . other modifications to the invention will also be apparent . for instance , for remote applications , both the trigger actuator 40 or 192 and the twist actuator 176 may be operated by solenoids , rather than manually . alternatively , the needle valve 90 or 188 and the twist valve 162 could themselves be replaced by tubes leading to valves located at a remote operator &# 39 ; s station . the remote valves may be solenoids or any other type of valve . if solenoid valves are used they may be pulsed open or closed at varying rates to allow a particular average flow through the relief ducts 100 or 194 and 168 , causing the corresponding valves 44 and 46 to maintain a particular position . in addition , the fog spray valve 46 could be threaded onto the main body 130 of the tip assembly 86 , and controlled by manual rotation rather than hydraulically . to the extent that such variations and modifications do not depart from the spirit of the invention , they are intended to be included within the scope thereof which is assessed only by a fair interpretation of the following claims . having fully described and disclosed the instant invention and alternately preferred embodiments thereof in such clear and concise terms as to enable those skilled in the art to understand and practice the same , the invention claimed is .
a firefighting nozzle includes a nozzle body having a having a centrally formed jet orifice at its outlet end . an annular fog spray opening concentrically surrounds the jet orifice . a jet control valve activated by a trigger is provided for allowing selective variation of the diameter of the solid stream emitted from the jet orifice . a fog control valve activated by a twist handle is provided for selectively varying the intensity of the discharge from the fog spray opening . the jet control valve and the fog control valve are operable independently of and simultaneously with one another , so that either a variable diameter solid stream or a variable fog cone , or both , can be produced at once .