Low-pressure livestock gun

Abstract

To provide a low pressure pneumatic stunner with a low-complexity valve and venting system, and a method of use thereof.SOLUTION: A stunner 20 has: a hooking part piston chamber 72; a stunning rod chamber 30; a housing 22; a supply passageway 84 of a pressurized fluid; a stunning rod 40; a stunning rod piston 48 slidable in the stunning rod chamber; a pair of elastic circular buffer materials 25 buffering stop of the stunning rod and the stunning rod piston; an opening between the elastic circular buffer materials; and an internal passageway 104 for supplying pressurized fluid near the elastic circular buffer materials. Pressurized fluid may alternately flow through the supply passageway to a rear end of the stunning rod chamber to drive the stunning rod forward or through the internal passage to the front of the stunning rod chamber between the pair of elastic circular buffer materials to drive the stunning rod backward.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates generally to pneumatic animal stunners for use in livestock / slaughterhouses. [Background technology]

[0002] In livestock factories, it is important to stun and immobilize animals for processing. On livestock farms, it is important to euthanize animals that are severely injured or irreversibly ill to prevent the spread of disease. While numerous methods have been used to stun and euthanize livestock, captive bolt mechanisms have proven to be the most efficient, inexpensive, and humane method for immobilizing animals. In particular, pneumatic captive bolt devices have been used for this purpose.

[0003] Pneumatic captive firearms with self-retracting stunning rods typically have complex valve systems that are more difficult to manufacture and tend to increase the cost of the captive firearm. Such valve systems also tend to increase the weight of the device, potentially increasing operator fatigue. A further problem is the need to deliver pressurized fluid at relatively high pressures, typically in the range of 175-220 psi (1.3-1.6 MPa). Portable captive firearms are generally lightweight, but the need to manually retract the stunning rod after firing increases operator fatigue. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, in view of the problems of the prior art, it is an object of the present invention to provide a pneumatic animal gun (stunner) and method of use that reduces the complexity of the valve and vent system and reduces manufacturing costs. It is also an object of the present invention to provide a pneumatic captive gun that is lighter in weight and reduces operator fatigue. It is a further object of the present invention to provide a pneumatic animal gun that allows for the reduction of pressurized fluid required for operation and has a robust construction that avoids accidental firing and damage. Other objects and advantages of the present invention will be in part obvious and in part apparent from this specification. [Means for solving the problem]

[0005] These and other objects which will be apparent to those skilled in the art are achieved in the present invention, which relates to a pneumatic captive stunner. the stunning rod piston connected to the stunning rod chamber and slidable within the stunning rod chamber; a pair of resilient annular buffers disposed in front of the stunning rod chamber to cushion the stunning rod and stunning rod piston from stopping when the stunning rod piston reaches the front of the stunning rod chamber; and an internal passage within the housing, having an opening in front of the stunning rod chamber between the resilient annular buffers, for supplying pressurized fluid from the supply source to the at least one resilient annular buffer in front of the stunning rod chamber, wherein the pressurized fluid can alternately flow from the supply source through the supply passage to the rear end of the stunning rod chamber to drive the stunning rod forward, or through the internal passage to the front of the stunning rod chamber between the pair of resilient annular buffers to drive the stunning rod rearward.

[0006] a first passage in the hook piston that is aligned with the housing supply passage so that air can flow from a pressurized fluid source to the rear end of the stunning rod chamber when the hook piston is in the first position; and a second passage in the hook piston that is aligned with the supply passage so that air can flow from the pressurized fluid source through the second passage to the front end of the stunning rod chamber when the hook piston is in the second position; and when the hook piston is in the first position, pressurized fluid can flow from the supply source through the supply passage and the first passage to the rear end of the stunning rod chamber when the hook piston is in the first position, thereby driving the stunning rod forward when the hook is released. After the latch is released, when the latch piston is in the second position, pressurized fluid can flow from the supply source through the supply passage and the second passage to the front end of the stunning rod chamber, driving the stunning rod rearward.

[0007] The pneumatic livestock gun has a latch that is released and the latch piston is in the second position. Pressurized fluid flows from the supply source through the supply passage and the second passage to the distal end of the stunning rod chamber, driving the stunning rod rearward and again moving the latch piston to the first position to hold the latch and prevent the stunning rod from moving forward.

[0008] The pneumatic captive gun further includes a stunning rod piston connected to the stunning rod and slidable within the stunning rod chamber, and a pair of buffers at the front end of the stunning rod chamber that cushion the stunning rod and the stunning rod piston from stopping when the stunning rod piston reaches the front of the stunning rod chamber.

[0009] The pneumatic captive gun further includes a stunning rod piston connected to the stunning rod and slidable within the stunning rod chamber, and a pair of buffers at the front end of the stunning rod chamber that cushion the stunning rod and the stunning rod piston from stopping when the stunning rod piston reaches the front of the stunning rod chamber.

[0010] The pneumatic captive gun further includes an internal passage within the housing extending from the latch piston chamber to between a pair of buffers at the front end of the stunning rod chamber, and when the latch piston is in the second position, pressurized fluid flows from the supply through the second passage within the latch piston and the internal passage to between the pair of buffers at the front end of the stunning rod chamber to drive the stunning rod rearward.

[0011] The pneumatic captive gun further includes a main on / off valve within the housing for controlling the flow of pressurized fluid from the supply to the supply passage.

[0012] In the pneumatic livestock gun, the latch piston has a central passage, and when the latch piston is in the first position, the first passage extends from the central passage to the supply passage and supplies pressurized fluid through the central passage to the rear end of the stunning rod chamber.

[0013] In the pneumatic livestock gun, the second passage of the latch piston is connected to the supply passage when the latch piston is in the second position, and has a passage opening in the outer wall of the latch piston that allows pressurized fluid to flow from the supply source through the passage opening and the supply passage to the front end of the stunning rod chamber.

[0014] The pneumatic livestock gun further includes an internal passage within the housing extending from the latch piston chamber to the front of the stunning rod chamber, and the latch piston second passage is connected to the supply passage and the internal passage when the latch piston is in the second position, and includes a passage port in the outer wall of the latch piston that allows pressurized fluid to flow from the supply passage, through the passage port provided in the latch piston, and the internal passage to the front end of the stunning rod chamber to drive the stunning rod rearward.

[0015] The pneumatic captive gun further includes a third passage in the latch piston that allows air to flow from the rear end of the stunning rod chamber through the latch piston central passage to the atmosphere while the stunning rod is being driven rearward.

[0016] The pneumatic livestock gun further includes a head contact at the front end of the housing that is movable between an inoperative position and a position that contacts the animal, and when the head contact is in the position that contacts the animal, air flows through the supply passage to urge the latch piston from the first position to the second position.

[0017] The method further relates to a method of stunning an animal. The method includes providing a housing having a latch piston chamber, a stunning rod chamber, and a front end forward of the stunning rod chamber; providing a supply passage within the housing for supplying pressurized fluid from a source of pressurized fluid to the rear end of the stunning rod chamber; providing a stunning rod slidable within the stunning rod chamber and drivable forward along a longitudinal axis and out of the housing front end; providing a stunning rod piston connected to the stunning rod and slidable within the stunning rod chamber; and disengaging the stunning rod and stunning rod when the stunning rod piston reaches the front of the stunning rod chamber. The method includes providing a pair of resilient annular buffers disposed in front of the stunning rod chamber to cushion the stopping of the stunning rod piston; and providing an internal passage within the housing having an opening at the front of the stunning rod chamber between the resilient annular buffers for supplying pressurized fluid from a pressurized fluid supply source to the front of the stunning rod chamber beside at least one resilient annular buffer, the pressurized fluid flowing alternately from the supply source through the supply passage to the rear end of the stunning rod chamber to drive the stunning rod forward, and through the internal passage to the front of the stunning rod chamber between the pair of resilient annular buffers to drive the stunning rod rearward.

[0018] In one embodiment, the method includes providing a latch mounted within the housing for repeatedly retaining and releasing the stunning rod; providing a latch piston disposed adjacent the latch and movable by sliding contact within the latch piston chamber between a first position retaining the latch and preventing forward drive of the stunning rod, and a second position releasing the latch and allowing forward drive of the stunning rod; providing a first passage within the latch piston aligned with the housing supply passage so that air can flow from the source of pressurized fluid to the rear end of the stunning rod chamber when the latch piston is in the first position; and providing a second passage within the latch piston aligned with the housing supply passage so that air can flow from the source of pressurized fluid to the rear end of the stunning rod chamber when the latch piston is in the second position. The method can include providing a second passage in the hanger piston aligned with the supply passage to allow air to flow to the front end of the stunning rod chamber; moving the hanger piston to a first position to retain the hanger and prevent the stunning rod from being driven forward; moving the hanger piston toward a second position to release the hanger; flowing pressurized fluid from the supply source through the first passage to the rear end of the stunning rod chamber to release the hanger and drive the stunning rod forward to stun the animal; and when the hanger piston is moved to the second position, flowing pressurized fluid from the supply source through the second passage to the front end of the stunning rod chamber to drive the stunning rod rearward.

[0019] The method can include, when the latch is released and the latch piston is in the second position, flowing pressurized fluid from the supply through the second passageway to the distal end of the stunning rod chamber to drive the stunning rod rearward, and moving the latch piston back to the first position to hold the latch and thereby prevent forward movement of the stunning rod.

[0020] The method may further include providing a central passage in the latch piston, and when the latch piston is in the first position, the first passage extends from the central passage to the supply passage and supplies pressurized fluid through the central passage to the rear end of the stunning rod chamber.

[0021] The method may further include the latch piston second passage having a passage opening in an outer wall of the latch piston that communicates with the supply passage when the latch piston is in the second position, allowing pressurized fluid to flow from the supply source through the passage opening and the supply passage to the front end of the stunning rod chamber.

[0022] The method further includes providing a third passage in the latch piston that allows air to flow from the rear end of the stunning rod chamber through the latch piston central passage to atmosphere while the stunning rod is being driven rearward. may include:

[0023] The features of the invention believed to be novel and the elements characteristic thereof are set forth with particularity in the appended claims. The drawings are for illustrative purposes only and are not necessarily drawn to scale. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the following detailed description taken in conjunction with the accompanying drawings, in which: [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a cross-sectional view of an embodiment of the captive firearm of the present invention, showing the trigger undepressed and the latch, latch piston, and stunning rod in a first, neutral, retained position before firing, and also after firing when the stunning rod is fully retracted and retained by the latch. [Figure 2] Figure 2 is a cross-sectional view of the captive gun shown in Figure 1 after firing, showing the trigger being depressed, the head contact being actuated and, a short time later, the latch releasing the stunning rod and moving it forward, with the latch piston advanced to an intermediate position between the first, retained position and the second, forward position. [Figure 3]FIG. 3 is a cross-sectional view of the captive gun shown in FIG. 1 after the firing shown in FIG. 2, showing the trigger depressed, head contact stopped, and the stunning rod in its fully forward, end-of-stroke position. [Figure 4] FIG. 4 is a cross-sectional view of the captive gun shown in FIG. 1 after the end-of-stroke position shown in FIG. 3, with the trigger depressed, head contact stopped, the stunning rod returned rearward to contact the front of the latch piston, and the latch piston moved rearward to an intermediate position between the second forward position and the first holding position. [Figure 5A] FIG. 2 is a perspective view of the captive gun shown in FIG. 1 as seen from the rear. [Figure 5B] FIG. 2 is a front perspective view of the captive gun shown in FIG. 1. [Figure 5C] FIG. 2 is a side view of the captive gun shown in FIG. [Figure 6] FIG. 2 is a cross-sectional view of the latch cylinder of the captive gun shown in FIG. [Figure 7] 2A is a front perspective view of the latch release piston of the livestock gun shown in FIG. 1, FIG. 2B is a front view, and FIG. 2C is a cross-sectional view. [Figure 8] 2 is a perspective view of a latch release piston and a latch of the captive gun shown in FIG. 1. FIG. [Figure 9] 2A is a side view of a latch release piston and a latch of the captive gun shown in FIG. 1, (B) is a rear view of the latch release piston, and (C) is a front view of the latch release piston and the latch of the captive gun shown in FIG. [Figure 10] 2A is a side view, FIG. 2B is a rear view, FIG. 2C is a front view, and FIG. 2D is a perspective view of the latching part in the livestock gun shown in FIG. 1. [Figure 11] (A) A side view of one of the hanging parts of the livestock gun shown in Figure 1, (B) A perspective view showing the inside of one of the hanging parts of the livestock gun shown in Figure 1, and (C) A perspective view showing the outside of one of the hanging parts of the livestock gun shown in Figure 1. [Figure 12] 2A and 2B are front and rear perspective views of the head contact activator of the captive gun shown in FIG. 1. [Figure 13]2 is a cross-sectional view of the housing nose of the captive gun shown in FIG. 1. [Figure 14] FIG. 10 is a side cross-sectional view of one embodiment of a stunner rod, liner, protrusion, and head contact configuration with the rod in a fully retracted position. [Figure 15] FIG. 15 is a side cross-sectional view of the captive gun configuration shown in FIG. 14 with the rod in a fully extended position. [Figure 16] FIG. 15 is an exploded perspective view showing the configuration of a protrusion and a head contact in the embodiment of the captive gun shown in FIG. 14. [Figure 17] 15 is an exploded side view showing the configuration of a protrusion and a head contact in the embodiment of the captive gun shown in FIG. 14. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0025] Although it includes parts outside the scope of the present invention related to the divisional patent application, specific examples of other configurations are disclosed below as substantial reference examples in order to understand the basic configuration of the livestock gun of the present invention. The housing (main body) has a latch piston chamber, a stunning rod chamber, and a front end forward of the stunning rod chamber. A supply passage is disposed within the housing between the pressurized fluid source and the latch piston chamber. The stunning rod is slidable within the stunning rod chamber and can be driven forward along the longitudinal axis and outward toward the front end of the housing. It can be driven forward along the longitudinal axis and outward toward the front end of the housing. A latch is disposed within the housing for repeatedly retaining and releasing the stunning rod. A latch piston is disposed in sliding contact within the latch piston chamber adjacent to the latch and is movable between a first position that retains the latch and prevents forward drive of the stunning rod, and a second position that releases the latch and allows forward drive of the stunning rod. When the latch piston is in the first position, a first passage within the latch piston is aligned with the housing supply passage, allowing air to flow from the pressurized fluid source to the rear end of the stunning rod chamber. When the latch piston is in the second position, a second passage in the latch piston is aligned with the supply passage, allowing air to flow from the pressurized fluid source through the second passage to the front end of the stunning rod chamber. When the latch piston is in the first position, pressurized fluid can flow from the supply source through the supply passage and the first passage to the rear end of the stunning rod chamber, driving the stunning rod forward when the latch is released. After the latch is released, when the latch piston is in the second position, pressurized fluid can flow from the supply source through the supply passage and the second passage to the front end of the stunning rod chamber, driving the stunning rod rearward.

[0026] After the latch is released, the latch piston may be in a second position, and pressurized fluid flows from the supply source through the supply passage and the second passage to the front end of the stunning rod chamber to drive the stunning rod rearward, and the latch piston is moved back to the first position to hold the latch, thereby preventing the stunning rod from moving forward.The stunning rod chamber may be provided at its front end with a stunning rod piston connected to the stunning rod and slidable within the stunning rod chamber, and a pair of buffers for cushioning the stopping of the stunning rod and stunning rod piston when the stunning rod piston reaches the front of the stunning rod chamber.

[0027] The pneumatic animal gun may further include an internal passageway within the housing (main body) that extends from the latch piston to between a pair of buffers at the front end of the stunning rod chamber. When the latch piston is in the second position, pressurized fluid can flow from the supply source through the second passageway within the latch piston and the internal passageway, and between the pair of buffers at the front end of the stunning rod chamber to drive the stunning rod rearward.

[0028] In another embodiment, the pneumatic animal gun can include a main on / off valve in the housing for controlling the flow of pressurized fluid from the supply source to the supply passage. The latch piston can include a central passage, and when the latch piston is in the first position, the first passage extends from the central passage to the supply passage and supplies pressurized fluid through the central passage to the rear end of the stunning rod chamber. The latch piston second passage can include a passage port in the outer wall of the latch piston that connects with the supply passage when the latch piston is in the second position, allowing pressurized fluid to flow from the supply source through the passage port and the supply passage to the front end of the stunning rod chamber.

[0029] The pneumatic animal gun may further include an internal passage within the housing extending from the hanger piston chamber to the front of the stunning rod chamber, and the hanger piston second passage may be connected to the supply passage and the internal passage when the hanger piston is in the second position, and may include a passage port in the outer wall of the hanger piston that allows pressurized fluid to flow from the supply passage, through the passage port provided in the hanger piston, and the internal passage to the front end of the stunning rod chamber to drive the stunning rod rearward.The pneumatic animal gun may further include a third passage within the hanger piston that allows air to flow from the rear end of the stunning rod chamber through the central passage of the hanger piston to the atmosphere while the stunning rod is being driven rearward.

[0030] The present invention also relates to a method for stunning an animal. a housing having a latch piston chamber, a stunning rod chamber, and a tip end forward of the stunning rod chamber; a supply passage between a pressurized fluid source (supply source) in the housing and the latch piston chamber; a stunning rod slidable within the stunning rod chamber and capable of being driven forward along the longitudinal axis and out of the housing tip; a latch mounted within the housing for repeatedly retaining and releasing the stunning rod; a latch piston disposed adjacent to the latch and movable by sliding contact within the latch piston chamber between a first position where the latch is retained and prevents the stunning rod from being driven forward, and a second position where the latch is released and the stunning rod is allowed to be driven forward; and a latch piston configured to allow air to flow from the pressurized fluid source to the rear end of the stunning rod chamber when the latch piston is in the first position. providing a first passageway in the hanger piston aligned with the housing supply passageway so that air can flow from a pressurized fluid source through the second passageway to the front end of the stunning rod chamber when the hanger piston is in the second position; moving the hanger piston to the first position to retain the hanger and prevent the stunning rod from being driven forward; moving the hanger piston toward the second position to release the hanger; allowing pressurized fluid to flow from the supply source through the first passageway to the rear end of the stunning rod chamber to release the hanger and drive the stunning rod forward to stunning the animal; and when the hanger piston is moved to the second position, allowing pressurized fluid to flow from the supply source through the second passageway to the front end of the stunning rod chamber to drive the stunning rod rearward.

[0031] In one embodiment of the reference example, when the latch is released and the latch piston is in the second position, pressurized fluid flows from the supply through the second passageway to the tip of the stunning rod chamber to drive the stunning rod rearward, and then moves the latch piston back to the first position to hold the latch and prevent the stunning rod from moving forward.

[0032] The method may further include providing a pair of buffers at the front end of the stunning rod chamber for cushioning the stopping of the stunning rod and stunning rod piston when the stunning rod piston reaches the front of the stunning rod chamber; providing an internal passage within the housing extending from the hanging piston chamber to the front of the stunning rod chamber between the pair of buffers; and flowing pressurized fluid from a supply through the second passage within the hanging piston and the internal passage to the front end of the stunning rod chamber between the pair of buffers to drive the stunning rod rearward when the hanging piston is moved to the second position.

[0033] In yet another embodiment of the preferred embodiment, the method includes providing a central passage in the latch piston, the first passage extending from the central passage to a supply passage and supplying pressurized fluid to the rear end of the stunning rod chamber through the central passage when the latch piston is in the first position. The latch piston second passage has a passage port in an outer wall of the latch piston that communicates with the supply passage when the latch piston is in the second position, allowing pressurized fluid to flow from the supply source through the passage port and the supply passage to the front end of the stunning rod chamber. The method can further include providing an internal passageway within the housing extending from the latch piston chamber to the front of the stunning rod chamber, the latch piston second passageway having a passageway opening in an outer wall of the latch piston that connects to the supply passageway and the internal passageway when the latch piston is in the second position, allowing pressurized fluid to flow from the supply source through the supply passageway, the passageway opening in the latch piston, and the internal passageway to the front end of the stunning rod chamber to drive the stunning rod rearward.

[0034] The method further includes providing a third passageway in the latch piston to allow air to flow from the rear end of the stunning rod chamber through the latch piston central passageway to atmosphere while the stunning rod is being driven rearward. The method also includes providing a head contact at the front end of the housing that is movable between an inoperative position and a position that contacts the animal, and when the head contact is in the position that contacts the animal, air flows through the supply passage to urge the latch piston from the first position to the second position. The method further provides for a latch piston to be held in the first position by an accumulation of pressurized fluid supplied from a supply passage in the latch piston chamber in front of the latch release piston portion and behind the latch retainer.

[0035] The method may further be directed to a pneumatic animal gun comprising a housing with a latch piston chamber, a stunning rod chamber, and a tip forward of the stunning rod chamber. A supply passage within the housing supplies pressurized fluid from a supply source to the rear end of the stunning rod chamber. The stunning rod is slidable within the stunning rod chamber and can be driven forward along the longitudinal axis and out of the front end of the housing. A stunning rod piston is connected to the stunning rod and slidable within the stunning rod chamber. A head contact at the front end of the housing has a rear portion extending through an opening at the front end of the stunning rod chamber and is movable between an inoperative position and an animal-contacting position. When in the inoperative position, it blocks the flow of pressurized fluid from the supply source to the rear end of the stunning rod chamber, and when in the animal-contacting position, it allows air to flow through the supply passage to bias the latch piston from the first position to the second position. An internal passage within the housing supplies pressurized fluid from the pressurized fluid source to the front of the stunning rod chamber. A passage is disposed between the rear of the head contact and the opening at the front end of the stunning rod chamber. When the head contact is in position to contact the animal, pressurized fluid flows from the supply source through the supply passage to the rear end of the stunning rod chamber, driving the stunning rod forward, and as pressurized fluid flows through the internal passage to the front end of the stunning rod chamber, driving the stunning rod rearward, a portion of the pressurized fluid flows through the passage between the rear of the head contact and the opening in the front end of the stunning rod chamber, moving the head contact inward to an inoperative position which blocks the flow of pressurized fluid from the supply source to the rear end of the stunning rod chamber.

[0036] In one embodiment of the preferred embodiment, the head contact includes a rear projection extending through an opening at the front end of the stunning rod chamber, and the passage between the rear of the head contact and the opening at the front end of the stunning rod chamber comprises a plurality of passage openings formed around the periphery of the rear projection of the head contact. The pneumatic air gun may further include at least one elastic buffer disposed at the front end of the stunning rod chamber to cushion the stunning rod and stunning rod piston when the stunning rod piston reaches the front of the stunning rod chamber. An internal passage within the housing can supply pressurized fluid from a supply source to the front of the stunning rod chamber past the at least one elastic buffer. The pressurized fluid alternately flows from the supply source through the supply passage to the rear end of the stunning rod chamber to drive the stunning rod forward, and flows through the internal passage past the at least one elastic buffer at the front of the stunning rod chamber to drive the stunning rod rearward.

[0037] As a non-limiting example, the following method for stunning an animal is also disclosed. a housing having a latch piston chamber, a stunning rod chamber, and a front end of the stunning rod chamber; a supply passage in the housing for supplying pressurized fluid from a supply source to the rear end of the stunning rod chamber; a stunning rod slidable within the stunning rod chamber and drivable forward along a longitudinal axis and out of the housing front end; a stunning rod piston connected to the stunning rod and slidable within the stunning rod chamber; a stunning rod piston having a rear end extending through an opening in the front end of the stunning rod chamber, movable between an inoperative position and an animal contacting position, wherein when in the inoperative position it blocks the flow of pressurized fluid from the supply source to the rear end of the stunning rod chamber and when in the animal contacting position it allows air to flow through the supply passage for moving the latch piston from a first position to a second position; providing an internal passage within the housing for supplying pressurized fluid from a supply source to the front of the stunning rod chamber; providing a passage between the rear of the head contact and an opening at the front end of the stunning rod chamber; upon contact between the animal and the head contact, pressurized fluid flows through the supply passage to the rear end of the stunning rod chamber to drive the stunning rod forward when the head contact is in a position to contact the animal; and when pressurized fluid flows through the supply passage to the front end of the stunning rod chamber to drive the stunning rod rearward, a portion of the pressurized fluid flows through the passage between the rear of the head contact and the opening at the front end of the stunning rod chamber to move the head contact to an inoperative position which blocks the flow of pressurized fluid from the supply source to the rear end of the stunning rod chamber.

[0038] The head contact includes a rear projection extending through an opening in the front end of the stunning rod chamber, and a passage between the rear of the head contact and the opening in the front end of the stunning rod chamber includes a plurality of passage openings formed around the periphery of the rear projection of the head contact, and a portion of the pressurized fluid flows through the passage openings in the rear projection of the head contact to move the head contact to an inoperative position that blocks the flow of pressurized fluid from the supply to the rear end of the stunning rod chamber. The method can further include providing a pair of buffers at the front end of the stunning rod chamber for cushioning the stopping of the stunning rod and stunning rod piston when the stunning rod piston reaches the front of the stunning rod chamber, and providing an internal passage within the housing for supplying pressurized fluid from a supply source to the at least one resilient buffer at the front of the stunning rod chamber. The pressurized fluid can alternately flow from the supply source through the supply passage to the rear end of the stunning rod chamber to drive the stunning rod forward, and through the internal passage to the at least one resilient buffer at the front of the stunning rod chamber to drive the stunning rod rearward.

[0039] As a further illustrative example, the present invention is directed to a pneumatic captive gun latch piston that is used to open and close a latch that alternately holds and releases to drive a stunning rod forward from a neutral position to stun an animal. A latch piston body is positioned adjacent to the latch and slidably fitted within the latch piston chamber, the latch piston having a predetermined length adapted to move between a first position urging the latch to retain the stunning rod and a second position allowing the latch to release the stunning rod. A central passage extends longitudinally along the entire length of the body. The first passage in the latch piston body allows air to flow from a pressurized air source through the first passage and the central passage to the rear end of the stunning rod when the latch piston is in the first position. The second passage in the latch piston body allows air to flow from a pressurized fluid source through the second passage to the front portion of the stunning rod when the latch piston is in the second position. The third passage in the latch piston body allows air to flow from the rear end of the stunning rod through the central passage in the latch piston to the atmosphere while the stunning rod is being returned to its neutral position.

[0040] In one embodiment of the latch piston, the second passageway includes a passageway opening in the outer wall of the latch piston that communicates with the supply passageway when the latch piston is in the second position, allowing pressurized fluid to flow from the supply source through the supply passageway and the passageway opening to the forward end of the stunning rod chamber.

[0041] A further example of the invention is a nose used to align and disalign fluid passages in a pneumatic animal gun. The passageway is for supplying pressurized fluid to launch the stunning rod and for venting the pressurized fluid after the stunning rod has been fired. The nose comprises an outer housing nose having a nose rear wall and an activator chamber disposed therein. The head contact activator is disposed within the outer housing nose and is slidable between a forward position and a rearward position, the head contact activator having a cylindrical projection and a cylindrical body. The head activator chamber passageway extends from a location adjacent to the head contact activator. A second passageway extends from a location adjacent to the head contact activator. The head contact passageway includes a passageway opening extending around the periphery of the cylindrical head contact body. The head contact vent is for venting accumulated pressurized fluid. When the head contact activator is in the forward position, the head contact passage is aligned and communicates with the second passage and the head contact vent to allow exhaust of accumulated pressurized fluid from the head contact vent, and when the head contact activator is in the rearward position, the head contact passage is aligned and communicates with the head activator chamber passage and the second passage to provide pressurized fluid to launch the stunning rod.

[0042] In one embodiment of the reference example, the head contact activator can be moved from a forward position to a rearward position by pressing the head contact activator against the animal's head. The device can further include a main trigger, a main handle valve, and a handle vent, and pressing the main trigger opens the main handle valve, supplying pressurized fluid to the head activator chamber passageway through the first valve passageway. When the main trigger is not pressed, the head contact passageway is not in communication with the head activator chamber passageway, and the second valve passageway is in communication with the handle vent, allowing any pressurized fluid in the head contact passageway to be vented to the atmosphere.

[0043] The present invention, as a reference embodiment, is further directed to a system for discharging pressurized fluid from a pneumatic captive gun, comprising a housing having a latch piston chamber, a stunning rod chamber, a tail end, and a tip end forward of the stunning rod chamber. A supply passage is located within the housing between a pressurized fluid supply source and the latch piston chamber. The stunning rod is slidable within the stunning rod chamber and can be driven forward along the longitudinal axis and out of the housing tip. A latch cylinder is attached to the rear end of the housing, and at least one exhaust passage is provided. A latch is located within the housing for alternately retaining and releasing the stunning rod. A latch piston is disposed adjacent to the latch and makes sliding contact within the latch piston chamber. An outer housing protrusion having a protrusion rear wall has an activator chamber disposed therein. A head contact activator is disposed within the outer housing protrusion and is slidable between a forward position and a rearward position. A head activator chamber passage extends from a position adjacent to the head contact activator. A head contact vent is disposed within the head contact activator for venting accumulated pressurized fluid, which accumulates until it drives the stunning rod forward and is subsequently vented through at least one vent passage in the latch cylinder and the head contact vent.

[0044] In one embodiment of the exemplary system, pressurized fluid accumulated at the rear end of the latch piston chamber may be vented through a head contact vent. Pressurized fluid accumulated at the rear end of the latch piston chamber may be vented through a head contact vent. A plurality of vent passages may be disposed within the latch cylinder. Pressurized fluid accumulated at the front end of the latch piston chamber may be vented through a plurality of vent passages disposed within the latch cylinder.

[0045] DETAILED DESCRIPTION OF THE INVENTION The following describes an embodiment of the present invention, with reference to Figures 1 to 3, in which like numerals refer to like features of the present invention.

[0046] The structure and operation of a typical captive firearm 20 are generally shown in cross-section in Figures 1-4, perspective and side views in Figures 5A-5C, and its components in Figures 6-13. Captive firearm 20 includes an elongated, outwardly extending hollow housing 22, a head contact activator 18 movable within an outer housing projection (nose) 23, a nose end 24, a butt end 26, a stunning rod 40 movable fore and aft about a longitudinal axis 80, and a latch 60 disposed about the longitudinal axis 80 for retaining and releasing the stunning rod 40. Captive firearm 20 is grasped by grasping a main handle 28 extending below housing 22 and a rear handle 29 extending from butt end 26. Forward and rearward directions referred to herein are relative to captive firearm nose end 24, and inward and outward directions referred to herein are relative to longitudinal axis 80. The housing 22 contains therein a generally cylindrical internal pressure or stunning rod chamber 30 for the stunning rod and piston, and a surrounding firing chamber 32 for receiving and retaining pressurized fluid.

[0047] A circular stunning rod piston 48, surrounded by an O-ring seal 49, slides along the cylindrical inner surface of the internal chamber 30 within the housing 22. The piston 48 moves forward and rearward along an axis 80, carrying the stunning rod 40. In the illustrated embodiment, the stunning rod and piston are integrally formed, but they may also be separate components fixed to one another. An annular firing chamber 32 surrounds the internal chamber 30 within the housing 22 and is open at the rear so that air can move freely and rapidly from the firing chamber 32 to the region of the internal chamber 30 behind the piston 48 upon firing of the stunner, as described further below. A nose rear wall 27 at the front of the chamber 30 limits the forward movement of the piston 48 and stunning rod 40 and carries a pair of resilient annular shock absorbers 25a, 25b. The rear end 41 of the stunning rod 40 has an opening with an inwardly facing edge 46 extending along its periphery, which edge is alternately retained and released by an outwardly extending flange 64 at the front end of the latch 60. The body or shaft of the stunning rod 40 may be circular or non-circular in shape when viewed in cross section perpendicular to its longitudinal axis. The front or striking end 44 of the stunning rod may extend with a snug fit through an opening 17 configured to correspond to the head contact activator 18 at the front of the housing 22 so that it is driven toward the animal's head when the latch releases the stunning rod edge 46. The front end 44 of the stunning rod may be sized with a diameter and shape suitable for penetrating or non-penetrating (i.e., causing concussion) the animal's head. The example shown in Figures 1 through 5C uses a penetrating rod.

[0048] In the illustrated embodiment, the latch system for retaining and releasing the stunning rod is located at the rear of the housing (main body) 22, behind the stunning rod chamber 30. The latch 60, further illustrated in Figures 8 through 11(C), is comprised of three arcuate latches arranged around an axis 80 in the illustrated embodiment. Each latch has a body curved in an arc about its longitudinal axis and has outwardly extending flanges 64 and 66 at its front and rear ends, respectively. In the illustrated embodiment, each latch 60 has an arc of greater than 90° but less than 120°, and the three latches can be arranged cylindrically around the longitudinal axis 80 with sufficient space between adjacent latches to pivot inward without interfering with each other. Fewer or more than three latches can be used. A latch retainer 70, which is generally hollow and cylindrical, extends forward from the rear end of the housing 22. The front portion of the latch retainer 70 wraps around and secures the rear end of the latch 60. The latch retainer 70 has an inward groove at its front end for receiving the latch rear flange 66, which extends away from the axis 80. The latch release piston 50 (see also Figures 7A-7C) is slidable within a central opening of a latch cylinder 75 (see also Figure 6) located at the butt end 26 of the air gun. Its front portion is slidably received within the central opening of the retainer 70, as shown in the cross-sectional views of Figures 1-4, and moves back and forth along the axis 80. The latch piston 50 has a circular release piston portion 52 that slides within a cylindrical latch piston chamber 72 behind the rear portion of the latch retainer 70. The latch release piston 50 has a central opening 58 extending along the axis 80 to the front end 51, and forward of the release piston portion 52 the latch release piston 50 has a generally cylindrical body portion that abuts within and against the rear end of the latch 60 (see also Figures 8 and 9(A)-(C)). The inner latch piston body and outer latch fixture support the rear ends of the latches, allowing the latches 60 to rotate and their respective front end flanges 64 to pivot inwardly and outwardly about their rear end flanges 66 in grooves in fixtures 70.

[0049] The front end of the latch can be moved outwardly away from the axis 80 to a holding position such that the front flange 64 contacts the rear end portion of the rod 40 to prevent the stunning rod from being driven forward. To achieve such movement, the latch piston 50 has a front end 51 within the latch that has a diameter sufficient to contact the front flange 64 of the latch and urge it outward to engage the stunning rod opening edge 46. When the latch piston 50 is moved rearward to the holding position, the front end 64 of the latch is aligned with and contacts both the stunning rod opening edge 46 and the front end portion 61 of the latch piston.

[0050] The latch piston has a relief portion 56 rearward of its front end 51, the diameter of which is smaller than that of the front end. The diameter of the relief portion is small enough to allow the latch front end 64 to move freely inward to the release position with the flange 64 disengaged from the stunning rod opening edge 46. When the latch piston 50 moves forward from the first position, which is the retention position, to the second position, which is the release position, the latch front end 51 is no longer in a position to prevent the latch front end 64 from moving inward. The rear side of the front flange 64 is chamfered at an angle greater than 90° relative to the latch body 62 (see also Figures 10(A)-(D) and 11(A)-(C)). Therefore, when the piston 48 and stunning rod 40 move forward, pressure from the stunning rod edge 46 causes the stunning rod edge to move along the chamfered flange surface 65, causing the flange 64 to spring inward within the release portion 56. When the front end flange 64 of the latch disengages from the rod edge 46, the stunning rod 40 is fully released and can be driven forward.

[0051] The captive stunner 20 may be operated by a pressurized fluid, such as compressed air or other suitable fluid. In the illustrated example, compressed air is the fluid, supplied by a hose or line connected to an air compressor. Air pressure and flow rate may be controlled by a regulator (not shown), and the compressed air flows into an inlet 82 in the housing 22 behind the main handle 28.

[0052] After inlet 82, the flow of pressurized air is then divided between an internal passage 84 and a trigger supply passage 92. Internal passage 84 communicates with latch release piston 50, the distal end of which may surround the piston, and trigger supply passage 92 communicates with a main valve 114 operated by a trigger 110 in handle 28. A spring (not shown) within valve 114 initially biases the valve to a downward position, biasing the trigger 110 to its undepressed position. When trigger 110 is in its undepressed position, a first passage 112a in main valve 114 allows air to flow from trigger supply passage 92 to supply passage 94, communicating with latch piston cylinder chamber 72.

[0053] When a source of pressurized fluid is connected via inlet 82, the latch release piston 50 is locked in the first, rearward, hold position, as shown in FIG. 1, the feed trigger 110 is not depressed, and the captive gun 20 is in a neutral position. Air can flow upward through passage 84, the distal end of which surrounds chamber 71 adjacent the rear of latch piston 50. When latch piston 50 is in the rearward, hold position, passages 84 and 85 are in communication (alignment). Because of the space between the individual latches 60, pressurized air can flow freely from passage 84 through passage 85, forward through central opening 58 within stunning rod lip 46, toward inner chamber 30, behind stunning rod piston 48, through the open rear end, and around the inner chamber to firing chamber 32. To place the latch release piston 50 in the holding position, aligning the first passage port 112a of the main valve 114 with the trigger 110 in the unpressed position allows pressurized air to flow through the supply passage 94 to the piston cylinder chamber 72 in front of the latch release piston member 52 and behind the latch fixture 70, urging the latch piston 50 rearward. This constant pressure holding of the latch piston 50 is maintained as long as the trigger 110 is not pressed, ensuring that the stunning rod 40 will not be accidentally discharged if the captive gun is dropped or mishandled.

[0054] The latch piston 50 includes a second passageway 89 within its body, rearward of the first passageway 85, which in the illustrated embodiment comprises an open-top passageway in the outer wall of the latch piston 50 that extends around all or part of the circumference of the latch piston 50. In the retained position of FIG. 1, the second passageway 89 is aligned with passageways 90a and 90b, the ends of which surround and connect to the latch release piston 50 and vent to atmosphere. The second passageway 89 is also aligned with passageway 104, which surrounds the chamber and extends from the latch release piston chamber 71 to the front end of the internal chamber 30, along and between the cushions 25a and 25b, communicating with one or more openings. Rearward of the second passageway 89, a third radial passageway 87 extends from a central opening around the body of the latch piston 50.

[0055] Pressurized fluid from the rear of the firing chamber 32 exerts a force against the stunning rod piston 48 and is held from forward movement only by the location of the latch flange 64 which holds the rear edge 46 of the stunning rod.

[0056] To actuate the firing of the stunning rod 40, embodiments of the present invention may employ a main trigger 110 that controls a main handle valve 114 in combination with a head contact activator 18. In the embodiment shown, the head activator chamber passage 96 extends forward from the main valve 114 through the handle and housing to the head contact activator 18. A passage 102 extends rearward from the head contact activator 18 to the rear end of the latch piston cylinder chamber 72. Passage 102 does not intersect with passage 104.

[0057] The head contact 18 slides back and forth within the forward projection 23 of the chamber 98 (see also FIG. 13 ) and is extended toward a forward (right) position under the pressure of a spring (not shown). In the forward, unactuated position, the rear portion or cylindrical projection 118 of the head activator 18 extends partially through an opening in the projection rear wall 27 at the rear of the activator chamber 98 and into an opening in the front buffer 25 a. The head contact passage 106 includes a passage opening that extends around the cylindrical body 120 of the head contact 18. When the trigger 110 is not depressed, the head contact passage opening 106 is not aligned with the passage 96 and the valve 114 is aligned with the second passage 112 b, venting air in the head activator passage 96 to the atmosphere through an opening in the handle 28. When the head contact 18 is in the forward position, the head contact passage 106 is aligned with both the passage 102 and the head contact vent 19, and when the latch release piston 50 is in the rearward position, the latch piston passage opening 89 is aligned with both the passage 104 and the vent passage 90b, with the rear end of the latch piston cylinder chamber 72 venting through the front of the housing 22 via vent 19 and the front end of the internal chamber 30 venting through the rear of the housing 22 via vent 90b, as shown in FIG. 1. The captive gun will not fire in this position with the main trigger 110 and head contact 18 not depressed. If desired, a second or auxiliary trigger 116 can be provided to open or close flow through the passage 102, which must be depressed to open the passage 102 and activate the stunning rod, as described further below. Providing this optional auxiliary trigger 116 may require accessing the passageway 102 at a point closer to the aft end 26 of the housing to allow for this additional safety feature without additional modifications to the flow path of the passageway 102, as shown in Figures 1-4.

[0058] To initiate a firing sequence, the main handle valve 114 is activated by the operator depressing the main trigger 110 with one hand against the force of a spring within the valve, causing the head contact 18 to move rearward (to the left) in the direction indicated by the arrow against the force of the head contact spring, as shown in Figure 2. This causes the rear of the head activator 18 to move further toward the rear opening of the activator chamber 98. When the main handle valve 114 is moved to its second, upper position, a first passageway 112a in the valve 114 connects passageway 94 to the handle vent opening, allowing pressurized air to be vented to atmosphere from the front end of the latch piston cylinder chamber 72, and a second passageway 112b in the valve 114 connects passageway 92 to passageway 96, providing pressurized air from inlet 82 to the head contact activator 18. With the head contact 18 in the rearward position, the head contact passageway opening 106 is aligned with the head activator passageway 96, allowing communication between the passageways 96 and 102.

[0059] The compressed air then flows through passage 102 to the rear end of the latch piston cylinder chamber 72. If the optional auxiliary trigger 116 is used, it must be depressed to open a valve and allow pressurized air to flow through passage 102. As a result of the main trigger 110 and head contact 18 being depressed and the optional auxiliary trigger 116 being depressed, the latch release piston 50 is moved by the compressed air at the rear of chamber 72 and begins to extend forward (to the right) to its limit against the latch retainer 70. This forward movement of end 51 releases the latch 60 and allows the front latch latch 64 to retract inward into the release section 56. The pressurized air behind the stunning rod piston 48 forces the stunning rod lip 46 forward, moving against the inclined latch flange surface 65 and moving the front end flange of the latch inward, releasing the stunning rod 40.

[0060] The pressure of the air from inlet 82 flowing through the latch piston central opening 58 (FIG. 1) is supplemented by the pressurized air flowing from firing chamber 32 against the rear of piston 48. As a result, when stunning rod 40 is released from the latch, it moves forward (to the right) at high velocity, and as shown in FIG. 2, the front or striking end 44 of the stunning rod moves through head contact opening 17 in the direction of the arrow as shown. Any remaining air in internal chamber 30 forward of stunning rod piston 48 that remains unexhausted begins to compress.

[0061] 2 shows the latch piston in an intermediate position as it moves forward from the first, retained position toward the second, released position. Passageway 85 moves out of alignment with passageway 84, thereby closing passageway 84 and preventing pressurized fluid from flowing through inlet 82. As the latch piston moves forward toward the released position, supply passageway 84 and first passageway 85 in the latch piston are no longer aligned, preventing further flow of pressurized fluid from the supply source to either the internal stunning rod chamber 30 or the firing chamber 32, even with operation of valve 114 depressing the supply trigger. Furthermore, as the latch piston 50 begins its forward movement toward the second, released position, the second passageway port 89 is not yet aligned with supply passageway 84.

[0062] 3 shows the captive gun 20 with the stunning rod 40 in its fully forward, end-of-stroke position. At the end of the forward stroke of the stunning rod 40, the piston 48 contacts the buffer 25b, compressing both buffers 25b and 25a at the forward end of the stunning rod chamber 30, slowing the forward movement of the piston 48 and rod 40 until they come to a halt within the stunning rod chamber. The stunning rod striking end 44 is now fully extended through the head contact opening 17.

[0063] With the latch piston 50 still in its second, forward position, pressurized fluid flows from the supply through the supply passage 84, through the passageway 89 extending around the latch piston 50, into the internal passageway 104, through the opening 34, and into the forward end of the stunning rod chamber 30 in front of the stunning rod piston 48 where the buffers 25a, 25b are located. A portion of the pressurized air flows from the front of the stunning rod chamber 30 through a passageway that includes one or more small passageways 108 between the rear or protrusion 118 of the head contact activator 18 and the opening in the rear protrusion wall 27 of the activator chamber 98. This pressurized air, together with the spring assist, moves the head contact 18 fully forward to its inoperative position. While one or more of these passage ports 108 can be formed in or around an opening in the protrusion rear wall 27 (FIG. 3), the embodiment shown in FIGS. 12(A) and 12(B) shows passage ports 108 consisting of four small holes or grooves arranged and formed around the rear portion or protrusion 118 of the head contact activator. When the head contact 18 is in the forward, inactivated position, further flow of pressurized fluid from the main valve 114 through passage 96 is blocked, and the head contact passage 106 connects with passage 102 and, thereby, with the head contact vent 19, venting exhaust pressure from the latch piston cylinder chamber. As a result, the latch piston 50 is no longer biased forward. This flow of air through passage 108 to push the head contact 18 forward acts as a safety, preventing repeated firing of the captive gun by holding down the trigger.

[0064] When the latch release piston 50 remains in the second forward position, the third radial passage 87 aligns with the vent passages 90a, 90b, allowing air behind the piston 48 to flow through the latch piston central opening 58 and be exhausted to atmosphere through the rear housing section 26. Pressurized air supplied to the forward end of the stunning rod chamber 30 from passage 104 acts against the stunning rod piston 48 and begins to drive it rearward.

[0065] As shown in Figure 4, the pressurized air at the forward end of chamber 30 retracts stunning rod 40 rearward (to the left, as indicated by the arrow) until lip 46 of stunning rod 40 passes behind front flange 64 of latch 60 and rear end 41 of the stunning rod contacts front end 51 of latch piston 50. Because latch piston cylinder chamber 72 is fully vented in front of and behind latch release piston portion 52, once the stunning rod piston contacts its front end, latch release piston 50 is free to begin its return from the second forward position toward the first, retained position. At an intermediate position between the second and first positions, second passage 89 of the latch piston has moved out of alignment with air supply passage 84, third passage 87 has moved out of alignment with vent passages 90a, 90b, and first passage 85 of the latch piston is not yet aligned with air supply passage 82. As a result, in this intermediate position, no additional pressurized air is supplied to the stunning rod chamber 30 in front of the stunning rod piston 48, and the stunning rod piston 48 is pushed back by the remaining air pressure.

[0066] However, as a result of the force of the piston 48, the latch piston 50 is retracted completely rearward (to the left) within the latch cylinder 75 into its first holding position. This rearward movement causes the forward ends 51 of the latch pistons to slide within the forward end portions of the latches, biasing them outwardly to close the latches 60 and cause the latch forward end flange 64 to engage and capture the stunning rod lip 46, so that the stunning rod 40 is held by the latch and the captive gun is automatically reset, as shown in Figure 1. When the trigger 110 is released by the operator and in the undepressed position, as shown in FIG. 1, with the latch piston 50 in the first, neutral, holding position, the captive gun is re-pressurized by air through the feed port 82 and the initial, lower position of the valve 114, as described above, so that pressurized air flows through the passage 94, urging the latch piston member 52 rearward, preventing forward movement of the latch piston 50 and stunning rod 40, and the captive gun is again ready to be operated.

[0067] Another embodiment is shown in Figures 14-17, in which a projection 23' and contact activator 18' are positioned at the front end 14' of an animal gun 20' and sized to accommodate a stunning rod 40' with a larger striking end 44'. This particular projection and head contact is for use with the embodiment of the captive gun 20' configured to not penetrate (i.e., concusse) the animal's head, as previously described.

[0068] The head contact 18' slides back and forth within the forward projection 23' of the chamber 98' and is biased toward the forward (right) position by the pressure of a spring 130. A projection valve 132 is located within the projection 23' and interacts with it through the sliding movement of the head contact 18'. In the forward, inactivated position, the cylindrical projection 118' of the head contact activator 18' extends partially through an opening in the forward end of the projection 23' and disengages from the projection valve 132. In this position, with the main trigger 110 and head contact 18' unpressed, the captive gun will not fire.

[0069] To initiate the firing sequence, the operator presses the main trigger 110 with one hand (and optionally the auxiliary trigger 116 with the other hand) to activate the main handle valve 114 against the spring force of the valve 114, and as shown in Figure 15, the operator moves the head contact 18' against the animal's head and pushes the head contact 18' backward (to the left) against the force of the spring 130, which activates the protrusion valve 32, causing the head contact tab 18' extending from the rear of the head contact 18' to engage with the protrusion valve 132, activating the protrusion valve 132 and allowing fluid to pass through.

[0070] The larger striking end 44' of the stunning rod 40' used in the captive gun 20' has a larger diameter than that of its penetrating counterpart 44, as described above. This striking end 44' is secured to the end of the rod 40' by a bolt, screw, nail, or other acceptable fastening means. The inner diameter of the head contact 18' is matched to the diameter of the striking end 44' to provide a snug fit that prevents rattle or movement of the rod during the firing sequence.

[0071] The rest of the firing sequence and structure of the captive fire gun 20' is similar to that described above for the piercing captive fire gun 20. Other salient features of the concussion captive fire gun 20' may also be constructed as described in U.S. Pat. No. 10,375,969, entitled "Concussion Captive Firearm Rod and Prongs," the disclosure of which is incorporated herein by reference.

[0072] The captive gun and its components can be made of steel, aluminum, composites, or other suitable materials. For example, the stunning rod can be constructed as described in U.S. Patent No. 10,258,051, "Lightweight Stunning Rod," the disclosure of which is incorporated herein by reference. The construction of the captive gun shown is sufficiently robust to prevent accidental discharge even if dropped by the operator.

[0073]

[0010] In view of the above, the present invention provides a pneumatic captive gun and method of use that has one or more of the following advantages: 1) Reduced complexity of valve and exhaust systems 2) Reducing the manufacturing costs of captive guns 3) Lighter automatic retractable (retraction) livestock guns 4) Reducing operator fatigue when using a livestock gun 5) Reducing the pressure of the pressurized fluid required to operate the captive gun. This is due to their low pressure, ranging from less than 175 psi (1.3 MPa) to approximately 125 psi (1 MPa), and their robust construction, which prevents accidental fire or damage.

[0074] While particularly described in connection with certain preferred embodiments, it will be apparent to those skilled in the art in light of the foregoing description that many alternatives, modifications, and variations are possible. Accordingly, the description and claims herein are intended to embrace all such alternatives, modifications, and variations that fall within the true spirit and scope of the invention.

Claims

1. a housing having a latch piston chamber, a stunning rod chamber, and a tip portion forward of the stunning rod chamber; a supply passage in the housing for supplying pressurized fluid from a supply source to the rear end of the stunning rod chamber; a stunning rod slidable within the stunning rod chamber and drivable forward along the longitudinal axis and out of the housing tip; a stunning rod piston connected to the stunning rod and slidable within the stunning rod chamber; a pair of resilient annular buffers located in front of the stunning rod chamber for cushioning the stopping of the stunning rod and stunning rod piston when the stunning rod piston reaches the front of the stunning rod chamber; an opening at the front of the stunning rod chamber between the resilient annular cushions; an internal passageway within the housing for supplying pressurized fluid from a supply source to the at least one resilient annular buffer in front of the stunning rod chamber; Equipped with Pressurized fluid is passed from a supply source through a supply passage to the rear end of the stunning rod chamber to drive the stunning rod forward. or through the internal passageway to the front of the stunning rod chamber between a pair of resilient annular buffers to drive the stunning rod rearward; A pneumatic livestock gun capable of alternate flow.

2. a latch attached to the housing for repeatedly retaining and releasing the stunning rod; a latch piston disposed in sliding contact within the latch piston chamber adjacent the latch, a first position in which the latch piston holds the latch and prevents the stunning rod from being driven forward; a first position in which the latching portion is released and the stunning rod is allowed to be driven forward; When the latch piston is in the first position, Allows air to flow from the pressurized fluid source to the rear end of the stunning rod chamber a first passage in the latch piston aligned with the housing supply passage; When the latch piston is in the second position, a second passage in the latch piston aligned with the supply passage so that air can flow from the pressurized fluid source through the second passage to the forward end of the stunning rod chamber; Equipped with when the latch piston is in the first position, pressurized fluid flows from the supply source through the supply passage and the first passage to the rear end of the stunning rod chamber to drive the stunning rod forward upon release of the latch; After the latch is released, when the latch piston is in the second position, 2. The pneumatic captive gun of claim 1, wherein pressurized fluid flows from the supply through the supply passage and the second passage to the front end of the stunning rod chamber to drive the stunning rod rearward.

3. When the latch is released and the latch piston is in the second position, pressurized fluid flows from the supply source through the supply passage and the second passage to the distal end of the stunning rod chamber to drive the stunning rod rearward; 3. A pneumatic captive gun as claimed in claim 2, wherein the stunning rod is prevented from moving forward by holding the latch by moving the latch piston back to the first position.

4. a stunning rod piston connected to the stunning rod and slidable within the stunning rod chamber; 4. The pneumatic captive gun according to claim 3, further comprising a pair of buffers at the front end of the stunning rod chamber for cushioning the stopping of the stunning rod and the stunning rod piston when the stunning rod piston reaches the front of the stunning rod chamber.

5. an internal passage within the housing extending from the latch piston chamber to between a pair of buffers in front of the stunning rod chamber; 5. The pneumatic livestock gun of claim 4, wherein when the latch piston is in the second position, pressurized fluid flows from the supply through the second passage and the internal passage in the latch piston and between a pair of buffers at the forward end of the stunning rod chamber to drive the stunning rod rearward.

6. 3. The pneumatic captive gun of claim 2, further comprising a main on / off valve within the housing for controlling the flow of pressurized fluid from the supply to the supply passage.

7. The latch piston has a central passage; 3. The pneumatic captive firearm of claim 2, wherein when the latch piston is in the first position, the first passage extends from the central passage to the supply passage and supplies pressurized fluid through the central passage to the rear end of the stunning rod chamber.

8. 3. The pneumatic captive gun of claim 2, wherein the latch piston second passage is connected to the supply passage when the latch piston is in the second position and has a passage port in an outer wall of the latch piston that allows pressurized fluid to flow from the supply source through the passage port and the supply passage to the front end of the stunning rod chamber.

9. further comprising an internal passageway within the housing extending from the latch piston chamber to the front of the stunning rod chamber; the second passage of the hook piston is connected to the supply passage and the internal passage when the hook piston is in the second position; 3. A pneumatic captive gun as claimed in claim 2, further comprising a passage port in an outer wall of the latch piston which allows pressurized fluid to flow from a supply passage, through the passage port in the latch piston, and through the internal passage to the forward end of the stunning rod chamber to drive the stunning rod rearward.

10. 8. The pneumatic captive gun of claim 7, further comprising a third passage in the latch piston that allows air to flow from the rear end of the stunning rod chamber through the latch piston central passage to the atmosphere while the stunning rod is being driven rearward.

11. a head contact at the front end of the housing, the head contact being movable between an inoperative position and a position for contacting the animal; 3. The pneumatic captive gun of claim 2, wherein air flows through the supply passage to urge the latch piston from the first position to the second position when the head contact is in the animal contact position.

12. providing a housing having a latch piston chamber, a stunning rod chamber, and a tip portion forward of the stunning rod chamber; providing a supply passage within the housing for supplying pressurized fluid from a source of pressurized fluid to the rear end of the stunning rod chamber; providing a stunning rod slidable within the stunning rod chamber and drivable forward along the longitudinal axis and out of the housing tip; providing a stunning rod piston connected to the stunning rod and slidable within the stunning rod chamber; providing a pair of resilient annular buffers positioned in front of the stunning rod chamber to cushion the stopping of the stunning rod and stunning rod piston when the stunning rod piston reaches the front of the stunning rod chamber; an internal passageway within the housing having an opening in front of the stunning rod chamber between the resilient annular cushions for supplying pressurized fluid from a source of pressurized fluid to the front of the stunning rod chamber by at least one resilient annular cushion; pressurized fluid flows from a supply source through a supply passage to a rear end of the stunning rod chamber to drive the stunning rod forward; Alternately flowing through an internal passageway to the front of the stunning rod chamber between a pair of resilient annular buffers to drive the stunning rod rearward. A method of stunning an animal by means of a pneumatic livestock gun, including:

13. The pneumatic livestock gun comprises: providing a latch located within the housing for repeatedly retaining and releasing the stunning rod; providing a latch piston disposed adjacent the latch and movable by sliding contact within a latch piston chamber between a first position which retains the latch and prevents forward drive of the stunning rod, and a second position which releases the latch and allows forward drive of the stunning rod; providing a first passageway within the latch piston aligned with the housing supply passageway for allowing air to flow from the source of pressurized fluid to the rear end of the stunning rod chamber when the latch piston is in the first position; providing a second passageway in the latch piston aligned with the supply passageway such that air can flow from a source of pressurized fluid through the second passageway to the forward end of the stunning rod chamber when the latch piston is in the second position; moving the latch piston to a first position to retain the latch and prevent the stunning rod from being driven forward; moving the latch piston toward a second position to release the latch; flowing pressurized fluid from the source through the first passageway to the rear end of the stunning rod chamber to release the latch and drive the stunning rod forward to stun the animal; when the latch piston is moved to the second position, pressurized fluid flows from the supply through the second passage to the forward end of the stunning rod chamber to drive the stunning rod rearward; 13. The method of stunning an animal of claim 12, comprising:

14. The pneumatic livestock gun is When the latch is released and the latch piston is in the second position, pressurized fluid flows from the source through the second passageway to the distal end of the stunning rod chamber to drive the stunning rod rearward; 14. A method of stunning an animal as claimed in claim 13, wherein the latch piston is moved back to the first position to hold the latch, thereby preventing the stunning rod from moving forward.

15. The pneumatic livestock gun is Furthermore, a central passage is provided in the latch piston; When the latch piston is in the first position, the first passage extends from the central passage to the supply passage for supplying pressurized fluid through the central passage to the rear end of the stunning rod chamber.

14. The method of stunning an animal of claim 13, comprising:

16. Furthermore, the second passage of the piston of the hook portion is a passage opening connected to the supply passage when the hook piston is in the second position is provided on an outer wall of the hook piston; allowing pressurized fluid to flow from the supply source through the passage port and the supply passage to the forward end of the stunning rod chamber; 14. The method of stunning an animal of claim 13, comprising:

17. The pneumatic livestock gun comprises: Additionally, a third passage is provided in the latch piston to allow air to flow from the rear end of the stunning rod chamber through the central passage of the latch piston to the atmosphere while the stunning rod is being driven rearward.

14. The method of stunning an animal of claim 13, comprising:

18. The pneumatic livestock gun is a head contact at the front end of the housing, the head contact being movable between an inoperative position and a position for contacting the animal; When the head contact is in a position to contact the animal, air flows through the supply passage to urge the latch piston from the first position to the second position.

14. The method of stunning an animal of claim 13, comprising:

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