examples of preferred embodiments of the present invention are illustrated and generally indicated by the reference numeral 10 in fig1 - 5 . the injector pump 10 is described below first in terms of its major structural elements and then in terms of its secondary structural and / or functional elements which cooperate to quickly and repeatably deliver an accurate dose under high pressure . the injector pump 10 generally comprises an inlet portion 12 , an outlet portion 14 , a firing portion 16 , and a manifold 18 . the inlet portion 12 , the outlet portion 14 , the firing portion 16 and the manifold 18 all have passages that are in fluid communication with each other . fig1 - 4 illustrate several embodiments of the injector pump 10 having different arrangements of these components . the exploded view of fig5 and the cut away views of fig6 a - 6c generally illustrate the design of these components . the inlet portion 12 has an ingress channel 20 , a stem 22 for attaching a hose or other fluid conduit from a fluid source , and an exterior threaded neck 24 . the outlet portion 14 has an egress channel 26 and a threaded neck 28 . the firing portion 16 has a firing piston 30 that slides within a firing cylinder 32 and forms a chamber 34 within the cylinder 32 . the manifold 18 has a passage 35 that provides fluid communication between the ingress channel 20 , the egress channel 26 , and the chamber 34 . a first one - way valve 36 , such as a ball - check valve , is positioned within the ingress channel 20 and a second one - way valve 38 is positioned within the egress channel 26 . the valves 36 and 38 control or govern the fluid flow within the injector pump 10 . fluid flows from the ingress channel 20 into the chamber 34 during an expansion stroke of the piston 30 and flows from the chamber 34 through the egress channel 26 during a compression stroke of the piston 30 . fig6 a - 6c illustrate the injector pump 10 prior to the compression stroke , after the compression stroke , and after the expansion stroke . these figures show a pre - primed device . the ingress channel 20 , egress channel 26 , and passage 35 are preferably constructed as small as operationally possible to reduce the amount of the air present within these passages during the priming of the pump 10 . furthermore , the channels 20 and 26 , the passage 35 , and the chamber 34 are precision machined to accurately deliver a desired volume of fluid corresponding to the volume of the chamber 34 , which is defined by the interior diameter of the cylinder 32 and the stroke distance of the piston 30 . the firing piston 30 is driven by a high - pressure actuation device to quickly drive the piston 30 through its compression stroke . the high - pressure actuation device may be a powerful spring 40 as shown in the figures , a compressed gas cartridge , a compressed air line , or other means for providing sufficient pressure to quickly fire or drive the piston through its entire compression stroke . the small cross sectional area of the firing cylinder 32 assists with the quick compression stroke motion . as shown in fig6 a - 6c , the spring 40 applies pressure the piston 30 and expels a high - pressure jet 44 of fluid from the pump 10 . each of the portions 12 , 14 and 16 may be integrally formed with the manifold 18 . however , as shown in the exploded view of fig5 the manifold 18 preferably has apertures 46 with interior threads . these interior threaded apertures 46 preferably have similar dimensions , including the diameter , the thread pitch , and the minimum and maximum thread diameters . fig5 shows the inlet portion 12 and the outlet portion 14 with similarly - dimensioned exterior threaded necks 24 and 28 . these similar dimensions include the diameter , the thread pitch , and the minimum and maximum thread diameters . the firing portion 16 is shown in this embodiment as being integrally formed with the manifold 18 . because of their similar design and dimensions , each neck 48 can be screwed into each of the apertures 46 in the manifold 18 . therefore , the inlet portion 12 and outlet portion 14 may exchange positions as seen in fig1 and 3 . the firing portion 16 may also be formed with a similarly dimensioned exterior threaded neck . thus , the injector pump 10 can form numerous configurations using prefabricated components . fig1 - 4 provide examples of these configurations . although threaded couplings are shown in the preferred embodiment , it is anticipated that other couplings or connectors could be used to attach the components to the manifold 18 within the teachings of this invention . fig4 shows a manifold 18 adapted to accommodate a firing portion 16 , an outlet portion 14 , and two inlet portions 12 . the inlet portions 12 allows fluid to be drawn from two separate fluid sources and mixed within the injector pump 10 . if the manifold 18 is designed with four threaded apertures 46 and if only one inlet portion 12 is required , a threaded plug ( not shown ) designed to adequately enclose the passage 35 may be screwed into the fourth aperture in the manifold 18 . the piston head 42 is designed to quickly , effectively , and efficiently displace fluid from the chamber 34 when the high - pressure actuation device forcefully drives the piston 30 through its compression stroke and expels fluid through the egress channel 26 . as shown most clearly in fig5 the piston head 42 preferably has two grooves 50 with an annular , rubber - like ring 52 seated within each groove 50 . the piston head 42 further has a beveled leading edge 54 . the overall design of the piston head 42 and the smooth interior of the cylinder 32 provide the piston 30 with a desired smooth , low - friction motion within the cylinder 32 . as shown in fig1 - 5 , the firing portion 16 may also include a nut - like sleeve 56 screwed into a threaded end of the cylinder 32 . the piston 30 extends through and has a low - friction , precision fit within the sleeve 56 . the sleeve effectively captures the piston head 42 within the cylinder 32 and guides the piston 30 during the compression and expansion strokes . fig1 - 5 also show a cap 58 screwed onto the end of the piston 30 . the spring 40 is effectively captured between the cap 58 and the sleeve 56 . the outlet portion 14 has a nozzle 60 with an outlet 62 in fluid communication with the egress channel 26 . a high - pressure jet 44 of fluid is expelled from the outlet 62 with sufficient force to provide a needleless , hypodermic injection into the flesh of an animal . referring to fig5 the nozzle 60 has an interior threaded surface and the outlet portion 14 has a second exterior threaded surface 64 on which the nozzle 60 is screwed . the nozzle 60 has a knurled surface 66 that assists with the manipulation of the nozzle 60 when it is being screwed on and off of the outlet portion 14 . a needle holder 68 may be screwed onto an exterior threaded surface 70 on the nozzle 60 and a hollow needle 72 having exterior threads 74 may be screwed into the distal end of the needle holder 68 . a mounted hollow needle 72 is in fluid communication with the egress channel 26 and may be used in the hypodermic dosing of animals . the injector pump 10 is preferably fabricated from a durable plastic material and is designed to withstand the repetitive force associated with the high - pressure actuation device . the injector pump 10 is precision machined to provide small passages 20 , 26 and 35 , and to provide a predetermined volume within the chamber 35 . this precision allows the pump 10 to repeatably and accurately expel predetermined volumes of fluid from the outlet 62 . the flexible design of the injector pump 10 provides significant manufacturing benefits . the same components can be used for a variety of pump design configurations allowing the manufacturer to realize larger economies of scale . fig7 shows an angled slap injector 80 , illustrated at approximately 90 degrees , incorporating an embodiment of the injector pump 10 similar to that shown in fig2 . fig8 shows a straight - on slap injector 82 incorporating an embodiment of the injector pump 10 similar to that shown in fig1 . the figures approximate the basic structural layout of two slap injector designs to illustrate the flexible design of the injector pump 10 . in both embodiments 80 and 82 , the slap injector generally comprises a handle 84 , a body part 86 , the injector pump 10 , operating means 88 , a latch or trigger device 90 , and triggering or actuating means 92 . a fluid conduit 96 provides fluid communication between a fluid source and the injector pump 10 . the body part 86 is mounted to one end of the handle 84 . the actuation means 92 is mounted on the body part 86 and , upon contacting an animal , triggers or actuates the trigger device 90 . the trigger device 90 is designed to latch and release the operating means 88 . in operation , the handle 84 is swung so that the actuating means 92 contacts the animal and is displaced relative to the body part 86 . the displaced actuating means 92 functions as a triggering mechanism to actuate the trigger device 90 , which is functioning as a latch device with respect to the operating means 88 . the actuated trigger device 90 releases the operating means 88 . the released operating means 88 fires or drives the piston 30 through a compression stroke and expels a high - pressure jet of fluid through the egress channel 26 and the outlet 60 . the operating means 88 for driving the piston 30 preferably comprises a high - pressure actuation device such as a compressed gas capsule , a compressed air line , or a strong spring 40 . preferably return means , such as a spring 94 , returns the actuating means 92 to its initial position relative to the body part 86 after fluid has been expelled from the outlet 60 . the figures show the operating means 88 , including the spring 40 and a coupling between the spring 40 and piston 30 , in a cocked position in which the spring 40 is stressed . the trigger device 90 latches the operating means in the cocked position . unlatching the trigger device 90 from the operating means 88 permits the operating means 88 to move to an uncocked position by allowing the spring 40 to expand . actuating the trigger device 90 allows the spring 40 to drive the piston 30 through its compression stroke to expel fluid through the egress channel 26 . preferably the operating means 88 and spring 40 extend longitudinally with respect to the handle 84 of either embodiment of the slap injector 80 and 82 . the actuating means 92 may contain a slap plate 98 designed to contact the animal . the slap plate 98 has an aperture 100 through which the high - pressure jet of fluid is expelled and through which the removable needle 72 may extend . fig7 and 8 show small barbs 102 extending from the slap plate 98 proximate to the aperture 100 . the barbs 102 facilitate a needless hypodermic injection by breaking the tough skin on animals allowing the high - pressure jet to effectively and consistently penetrate into the muscular tissue . the figures also show a marking element 104 positioned on the slap plate 98 . the marking element 104 contains an ink - like substance that leaves a mark on the skin of the animal upon contact . the marking element 104 is therefore useful to identify whether an animal has been treated and to identify the location of the treatment . the descriptions above and the accompanying drawings should be interpreted in the illustrative and not the limited sense . while the invention has been disclosed in connection with the preferred embodiment or embodiments thereof , it should be understood that there may be other embodiments which fall within the scope of the invention as defined by the following claims . where a claim , if any , is expressed as a means or step for performing a specified function it is intended that such claim be construed to cover the corresponding structure , material , or acts described in the specification and equivalents thereof , including both structural equivalents and equivalent structures .
a pump , comprising an inlet portion having an ingress channel , an outlet portion having an egress channel , a firing portion , and a manifold having a passage in fluid communication with the ingress channel , the egress channel , and the chamber . the firing portion includes a firing cylinder and a firing piston . the firing piston is capable of performing compression strokes and expansion strokes within the firing cylinder . the firing cylinder forms a chamber in which fluid is drawn during an expansion stroke . a high - pressure actuation device drives the firing piston during the compression stroke to expel a high - pressure jet of fluid from the egress channel . if an injector device is held proximate to flesh , the jet of fluid has sufficient pressure to hypodermically inject the fluid without a needle . the inlet portion , outlet portion , and firing portion of the pump can be rearranged on the manifold to conform to the design requirements for a variety of slap injectors .