US 3579889 A
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Description (OCR text may contain errors)
United States Patent 3,067,454 12/1962 Catlin et al. t.
3,068,601 l2/l962 Arrowsmith Inventor Appl. No.
Filed Patented Assignee Priority Adolf Pallich Brno, Czechoslovakia 805,516
Mar. 10, 1969 May 25, 1971 Zbrojovka, narodni podnik Brno, Czechoslovakia Mar. 18, 1968 Czechoslovakia ANESTHETIZING GUN FOR USE IN 42/l(M) /1(M) Primary ExaminerBenjamin A. Borchelt Assistant Examiner-Charles T. Jordan An0rney-Arthur O. Klein ABSTRACT: An anesthetizing gun to be used in connection with the slaughtering of animals. The gun has a barrel which at its muzzle end is provided with a bore through which an anesthetizing instrument is axially guided. A piston is fixed to the rear end of the instrument and is slidable in the gun barrel while a suitable structure behind the piston supplies a gas under pressure to drive the piston forwardly to displace the instrument forwardly beyond the muzzle along its working stroke. The barrel is formed with passages communicating with the interior of the barrel and having front and rear ends displaced from each other along the barrel axis by a distance greater than the axial length of the piston, with the latter moving along these passages during part of the stroke of the piston, so that the gas under pressure can flow through these passages from the rear to the front of the piston within the barrel and also through these passages from the front to the rear of the piston within the barrel. The barrel has at least one discharge opening through which the gas can escape, but this opening is closed by the piston itself when the gas flows through the passages around the piston.
ANESTI-IETIZING GUN FOR USE IN SLAUGHTERING ANIMALS BACKGROUND OF THE INVENTION The present invention relates to anesthetizing devices.
In particular, the present invention relates to anesthetizing guns used in connection with the slaughtering of animals such as cattle, or the like.
Thus, it is known to prepare such animals for slaughter by anesthetizing them with suitable needles which are driven into the animals through their hides while a suitable anesthetizing agent is injected, as in well known. Such anesthetizing instruments can be driven into the animal by way of a fluid under pressure, such as the gas resulting from the explosion of a suitable cartridge which can be ignited after being loaded into the gun.
The anesthetizing instrument must have sufficient energy to provide for the complete anesthetizing of animals including those with extremely dense hides. In addition it is essential that after the anesthetizing of the animal the anesthetizing instrument be safely retracted to its initial position within the gun. v
Up to the present time, rifle barrels have been used to direct the anesthetizing instrument to its target. Such barrels terminate at one end with the cartridge chamber which is loaded and closed by means of a suitable breech mechanism also provided with a suitable igniting device for operating the gun. At its front end the gun is provided with a muzzle formed with a bore through which the anesthetizing instrument is guided, this instrument being fixed to a piston which is within the barrel, slidable therein. In the rest or retracted position of the piston and instrument, the piston is situated at the front end of the cartridge chamber. In order that the explosive gases may escape after driving of the piston and anesthetizing instrument forwardly, the muzzle of the conventional guns are provided with discharge passages for the gas. In order to retract the anesthetizing instrument, a spring is most frequently used, this spring being of coiled cylindrical configuration and acting to retract the parts to their initial position in a well-known manner. This ring will, for example, surround the anesthetizing instrument and be compressed between the rear end ofthe muzzle and the front end of the piston so as to expand after the explosion in order to return the piston back to its starting position. In order to dampen the impact of the piston upon firing of the gun and at the same time to limit the extent of outward driving of the anesthetizing instrument, which is driven outwardly by a distance on the order of -6 cm. beyond the muzzle of the gun, a rubber cushioning insert is used, this insert being situated between the spring and the barrel.
The disadvantage of these conventional structures resides in the fact that the spring and rubber cushion insert have only a small operating life, these components moving at localized areas during the firing. As a result it becomes essential during operation ofthe slaughtering installation to daily change these components several times. Such frequent exchange of these components presents great disadvantages, such as, among others, interfering with the smooth movement of the cattle. Furthermore, it often happens that as a result of the impact of the piston against the front end of the cartridge chamber upon retraction of the instrument, the cartridge chamber body breaks. The damping medium situated between the piston and the front end of the cartridge chamber is in its entirety of only small effect, and such damping mediums also break during the operations. Furthermore a considerable disadvantage resides in the fact that the speed of movement of the anesthetizing instrument is retarded from the very beginning at its initial portion by the spring.
SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to provide a construction which will avoid the above drawbacks.
In particular, it is an object of the invention to provide a construction capable of cushioning the movement of the piston within the barrel while at the same time avoiding the use of any components such as rubber cushions, coil springs, and the like.
Thus, it is an object of the invention to provide a construction which will avoid the necessity of frequent changing of components which cannot withstand the stresses to which they are subjected for any substantial length of time.
In particular, it is an object of the present invention to provide a construction which will utilize the pressure of the driving gas itself for the cushioning and return stroke of the piston.
Also, it is an object of the invention to provide a construction of this type which will reliably seal the gases within the barrel while at the same time controlling the flow of gases out of the barrel in an efficient manner.
In accordance with the invention the barrel has an axially bored front muzzle end through which the anesthetizing instrument is guided. This instrument is connected at its rear end to a piston which slides within the barrel, and to the rear of the piston is a means for supplying a gas under pressure which acts on the piston to drive the latter forwardly together with the anesthetizing instrument. The barrel of the invention is provided with a passage means having front and rear ends communicating with the interior of the barrel and situated from each other along the axis of the barrel by a distance greater than the axial length of the piston. As a result, the gas which drives the piston forwardly can flow through this passage means to the front of the piston to cushion the forward movement thereof as well as through the passage means from the front to the rear of the piston to cushion the return movement of the piston and thus protect the cartridge chamber. At least one discharge opening is provided for discharge of gas out of the barrel, and this opening is itself controlled by the piston to be closed thereby during flow of the gas through the passage means around the piston.
Thus, with the structure of the invention there are the advantages of extreme simplicity, reduction in the number of moving components, achievement of a device which is more fully capable of performing as desired, and also increasing the operating life of all of the components.
BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:
FIG. 1 is a fragmentary, longitudinal, sectional partly schematic illustration of a gun according to the invention, FIG. 1 showing that part of the gun which is provided with the structure of the invention;
FIG. 2 shows the structure of FIG. 1 after the piston has moved forwardly from its starting position in FIG. 1;
FIG. 3'is a front end view of the structure of FIG. I as seen from the left thereof;
FIG. 4 is a transverse cross section taken along line A-A of FIG. 1 in the direction of the arrows, FIG. 4 illustrating the relationship between the gas discharge openings and the passage means in the interior of the barrel.
DESCRIPTION OF A PREFERRED EMBODIMENT The device of the invention includes a rifle barrel 1 carrying at one end the cartridge chamber 2 and provided at its other end with an axially bored muzzle 3. This muzzle 3 is provided at its rear end portion with an annular recess which receives a sealing ring assembly 5 which is urged radially toward the axis of the barrel, the muzzle 3 being formed with an axial bore 6 through which the schematically illustrated anesthetizing instrument 7 extends. In the rest position shown in FIG. 1, the front end of the instrument 7 is flush with the front end of the muzzle 3.
The rear end of the instrument 7 is fixed to the reciprocating piston 8 which at its rear end is connected with a rear axial extension 9. Thus, the instrument 7 passes through the guide opening 6 of the muzzle as well as through the seal 5 which forms a sealing means slidably surrounding and engaging the instrument 7 to provide a fluidtight coaction therewith. The rear extension 9 ofthe piston is received in an opening 10 formed at the front end of the cartridge chamber 2. A second sealing means in the form of a piston ring 11 is provided directly on the piston 8 surrounding the latter and engaging the inner surface of the barrel 1 so as to have a fluidtight sliding engagement therewith. The frictional engagement between the pair of sealing means 5 and 11 with the instrument 7 and barrel 1, respectively, serve to maintain the parts in the starting position shown in FIG. 1.
In accordance with the invention a passage means 12 is pro vided in the interior of the barrel 1 communicating with the interior space thereof. In the illustrated example the passage means takes the form of a plurality of elongated grooves 12 formed in the interior surface of the barrel 1 and each having in cross section the configuration shown most clearly in FIG. 4. These grooves 12 of the passage means respectively have rear ends 16 all'located in a common plane normal to the barrel axis and front ends 18 also all located in a common plane normal to the barrel axis. It will be noted that in the rest position of the parts shown in FIG. 1 the rear ends 16 of the passage means 12 are located approximately at the region of the front end 13. of the piston 8 when the rear end 14 thereof engages the front end of the cartridge chamber 2.
While the passage means 12 is shown as extending axially, it can also be oriented differently. Circumferentially spaced between the grooves or passages 12 substantially midway between the ends thereof are a plurality of discharge openings 15 which are formed through the wall of the barrel 1. The length of the passage means 12 from the rear end 16 to the front end 18 thereof is greater than the axial length of the piston 8. This axial length of the piston 8, between its front and rear end faces 13 and 14, is at least as great as the axial distance from the rear ends 16 of the grooves 12 up to the forwardmost portions 17 of the discharge openings 15, and in the same way the axial length of the piston 8 is at least as great as the axial distance between the front ends 18 of the passages 12 and the rearmost portions 19 of the discharge openings 15. These distances are of course taken along the axis of the barrel 1. The location and lengths of the passages 12 are selected in such a way that the desired movement of the anesthetic instrument 7 out of the barrel will be achieved.
The discharge openings 15 communicate with a discharge chamber 20 which is defined between the barrel 1 and an exterior casing 21 which surrounds and is paced from the barrel 1 in the manner shown in FIGS. 1, 2, 4. Thus, the front end of the casing 21 is carried by an outer peripheral portion of the muzzle 3, which is simply threaded into the front end region of the barrel 1 to form a muzzle end for the latter, while the rear end of the casing 21 is carried by a shoulder formed at the exterior of the barrel 1. As is particularly apparent from FIG. 3, the muzzle 3 is formed with a plurality of discharge bores 22, and, as is apparent from FIGS. 1 and 2, these bores communicate with the chamber 20, so that the gases can escape out of the discharge openings 15 through the chamber 20 and out through the discharge openings 22. The total cross-sectional area of all of the openings 22 can be less than, equal to, or more than the total cross-sectional area of all of the openings 15. The barrel 1 is connected by way ofthe cartridge chamber 2 to the breech component 23 which is provided with an operating lever 24. These components form no part of the present invention so that they are not further described.
After ignition of a cartridge 25 situated in the chamber 2, the gas under pressure, which is created, exerts its force on the extension 9 to displace the piston 8 and the instrument 7 for- Immediately thereafter the gas which is under pressure, operating exclusively up to this time on the rear end face 14 of the piston 8, now flows through the passage means 12 from the rear chamber 27 of the barrel into the front chamber 26 thereof in front of the front end face 13 of the piston. This flow of gas forwardly through the passage means 12 from the rear chamber 27 to the front chamber 26 takes place until the front end 13 of the piston reaches the front end 18 of the passage means 12. At this instant the rear end 14 of the piston 8 uncovers and opens the discharge opening 15 through which the remaining gas in the chamber 27 discharges out through the chamber 20 and discharge bores 22 to the outer atmosphere.
Because of their inertia, the instrument 7 and piston 8 continue their forward movement but now there is located between the muzzle 3 and the front 13 of the piston 8 a gas which is compressed to an increasing extend as the piston 8 and instrument 7 continue to advance forwardly, so that with this increasing pressure of gas which cannot escape beyond the pair of sealing means 5 and 11, the forward movement of the instrument 7 and piston 8 is retarded and damped. Thus, the compression of the gas in front of the piston continues as long as the pressure of the gas in front of the piston 8 does not achieve a force great enough to bring about termination of the forward movement of the piston 8 and the initiation of the return movement thereof. When this latter force is achieved, however, the compressed gas will expand to bring about the return movement of the piston 8 and the retraction of the anesthetizing instrument 7.
During the return movement of the piston 8, at the instant when the front end 13 thereof reaches the front end 18 of the passage means 12, the rear end 14 of the piston 8 has just covered the discharge openings 15 so as to prevent the compressed gas from discharging out of the barrel into the outer atmosphere. Instead during the continued retraction of the piston 8 the gas flows rearwardly through the passage means 12 from the chamber 26 into the chamber 27 between the end surface 14 of the piston 8 and the body of the cartridge chamber 2. This operation continues until the rear end 14 of the piston 8 reaches the rear end 16 of the passage means 12. At this instant the front end 13 of the piston 8 uncovers the discharge openings 15 so that the residual gas in front of the piston can now escape to the outer atmosphere. The remaining gas between the rear 14 of the piston 8 and the cartridge chamber becomes compressed to retard and resist the rearward movement of the piston so as to brake at least partially the rearward movement of the piston and thus the piston 8 will reach the front end of the cartridge chamber 2 upon returning to its starting position while being cushioned by part of gases initially developed from the cartridge 25.
It is to be noted that the operating cycle which has been described in detail above actually takes place very quickly. Thus, the movement of the anesthetizing 7 forwardly, so as to anesthetize the animal, and the movement of the instrument 7 rearwardly during retraction out of the head of the animal, taken place in an extremely short time.
Of course, instead of using an explosive powder to achieve the driving force to actuate the instrument 7 in connection with the barrel, it is also possible to use suitable pneumatic systems having metering units which will meter a given amount of compressed air or the like to the assembly for driving the piston and instrument forwardly in the manner described above.
What I claim is:
1. In a device to be used in connection with the slaughtering of animals, a barrel having a front axially bored muzzle end, an anesthetizing instrument axially guided through said bore of said muzzle end of said barrel, a piston slidable in said barrel and connected with the rear end of said instrument, means located behind said piston for supplying to the latter a fluid under pressure for driving the piston forwardly in the barrel to displace the instrument forwardly out of the muzzle end thereof, elongated passage means formed in said barrel,
located along the path of movement of said piston therein, communicating with the interior of said barrel, and having front and rear ends displaced from each other along the axis of the barrel by a distance greater than the axial length of said piston, so that as said piston is driven forwardly the gas under pressure can flow through said passage means from the rear to the front of the piston while when the latter returns rearwardly the fluid under pressure can flow from the front back to the rear of the piston through said passage means, and said barrel being formed with at least one discharge opening closed by said piston when the gaseous fluid flows around said piston through said passage means.
2. The combination of claim 1 and wherein said piston has an axial length at least as great as the distance between the rear end of said passage means and the forwardmost part of said discharge opening as well as at least as great as the distance between the front end of said passage means and the rearmost part of said discharge opening.
3. The combination of claim 2 and wherein an outer casing surrounds said barrel and is spaced therefrom to provide a chamber communicating with said discharge opening, and said muzzle end of said barrel being formed with additional outlets through which the gas can discharge from said chamber.
4. The combination of claim 3 and wherein a pair of sealing means are respectively located one at said muzzle end of said barrel surrounding the instrument and the other between said piston and the inner surface of said barrel for providing a sealed sliding engagement between the instrument and the muzzle end of the barrel and between the piston and the inner surface of the barrel.
5. The combination of claim 2 and wherein said passage means includes a plurality of axially extending grooves formed in the inner surface of said barrel and circumferentially spaced about the axis thereof with all of said grooves having, respectively, rear ends located in a predetermined plane normal to the barrel axis and front ends located in a predetermined plane normal to the barrel axis.
6. The combination of claim 5 and wherein a plurality of said discharge openings are formed in said barrel circumferentially between said grooves and axially midway between the ends of said grooves.