US 3212490 A
Description (OCR text may contain errors)
Oct. 19, 1965 R. MERZ AIR GUN Filed Nov. 21. 1961 vm 5 mm mm m OE w w N g 7 8 -1 HHH V mm 6 w mm m mm Q INVENTOR.
RU DOLF ME RZ ATTORNEY l j United States Patent AIR GUN Rudolf Merz, Rochester, N.Y., assignor to Crosman Arms Company, Inc., Rochester, N.Y., a corporation of New York Filed Nov. 21, 1961, Ser. No. 153,802 6 Claims. (Cl. 124-15) This invention relates to air guns.
The ordinary air gun is of the lever action type. An elongate arm, which is pivoted to the barrel or stock of the gun, is connected by linkage to a piston; and to compress the air for firing the gun, it is necessary first to rock this arm. The arm is either vigorously pumped about its pivot to compress the air, or moves a spring-loaded piston to cocked position. The former requires the expenditure of considerable energy. Both arrangements call for the employment of a relatively large number of bulky working parts.
Attempts have been made from time to time to bulld guns with bolt-operated pistons. In such an airgun, a spring-loaded piston is moved to a cocking position at the rear of an air chamber, by means of a manually operable bolt, and is held there by the trigger. When the trigger is tripped, the spring-loaded piston moves forwardly to compress the air in the forward end of the chamber and to force the compressed air against the projectile to cause it to be propelled from the gun barrel. While such bolt-operated piston type air guns have the advantage that they eliminate the cumbersome parts employed in the pump type of air guns, prior bolt-operated air guns have had the disadvantage of producing a limited propelling force, hence a restricted range.
A primary object of this invention is to provide an air gun having a manually-cockable piston for compressing the air required to fire a projectile, and so constructed that firing cannot take place until the air has been compressed to a predetermined degree.
Another object of this invention is to provide an improved air gun of the type described which is relatively compact and easily operable.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawing.
In the drawing:
FIG. 1 is a side elevation of one embodiment of the invention, and with parts broken away to show the interior of the gun;
FIG. 2 is a sectional view on an enlarged scale taken along the line 22 of FIG. 1 and looking in the direction of the arrows; and
FIG. 3 is an enlarged fragmentary view of the valve employed in this gun.
Referring now to the drawing by numerals of reference, the gun comprises a stock 11 that supports an elongate tube 12. Tube 12 is closed at its rear end by a plug 13, and is secured adjacent its rear end to stock 11 in conventional fashion by means of a pin 15 and a screw 16 that threads therein. At its forward end, tube 12 is secured to stock 11 by a conventional clamp 17. Clamp 17 surrounds the tube 12 and is secured in the bottom of a recess in the top of stock 11 by a screw 18 which passes through the stock and is threaded into a nut 19 interposed between clamp 17 and the tube 12.
Positioned in the tube 12 for reciprocation axially thereof is a hollow, generally cup-shaped valve block or holder 20. A resilient O ring 21, which is disposed in an annular recess in the periphery of holder 20 and which has its outer surface snugly engaged with the inside of tube 12, provides an air-tight seal between the tube and 3,2l2,490 Patented Oct. 19, 1965 the holder. The rear end of the block 20 has a plurality of angularly-spaced ports 22 extending through it and arranged in a circle.
Slidably mounted in the block 20 is a valve 23 which has an enlarged head portion 24 at its rear end and a stem 25 projecting forwardly from its head. The valve has an axial bore 26 extending through it, both through its head and its stem. The head portion of the valve slides in a cylindrical guide surface 27 formed internally in valve block 20; and the stern portion 25 of the valve slides in a cylindrical guide surface formed by the bore in gun barrel adjacent the rear end thereof. The head portion 24 is adapted to seat at its rear end against the rear end of block 20 to close off the ports 22. A compression spring 28, which is disposed about the stem 25 of the valve and which is interposed between the head 24 of the valve and the bottom 29 of a countersink in the rear end of the gun barrel, serves to constantly urge valve 23 to closed position to close ports 22. The valve block 20 is threaded over the rear end of the gun barrel 30 as shown in FIG. 3.
Mounted in tube 12 and disposed about barrel 30 forwardly of valve block 20 is an elongate projectile guide 31 which is generally C-shaped in cross section. At its rear end guide 31 abuts against the front face of block 20. Adjacent its forward end, guide 31 is secured to the underside of barrel 30 by means of a screw 32 which is threaded at one end into barrel 30 (FIG. 1); and which at its opposite end projects down into an elongate slot formed in the bottom of tube 12. The forward end of barrel 30 is slidably mounted in an axially bored plug 33 which is threaded into the front end of tube 12, and which engaegs the front end of guide 31 when barrel 30 is in its forward position as shown in FIG. 1, thereby acting as a stop to limit forward movement of the barrel and guide in the tube 12. Guide 31 is positioned in tube 12 so that the axially extending space or slot 34 defined by its confronting, elongate edges is aligned with a projectile loading aperture 36 provided in the top of clamp 17.
Barrel 30 is flatted off at its top for a portion of its length as denoted at 51. When barrel 30 is in its for- Ward position (FIG. 1) fiat 51 extends from a point adjacent the projectile loading apenture 36 in clamp 17, readwardly to the valve block 20. The portion of screw 32 which projects into the slot 35 in tube 12 prevents barrel 30 and guide 31 from being rotated relative to tube 12. Screw 32 also keeps the flat 51 on barrel 30 aligned with slot 34 in guide sleeve 31 for guiding conventional BB type projectiles B rearwardly of the gun from the projectile loading aperture 36 to a radial duct 53 which communicates with the bore 54 of the gun barrel and through which the projectiles are fed one at a time into the barrel bore 54. Barrel 30 has a further radial duct 55 in it which is disposed slightly forwardly of duct 53 and at right angles thereto. Adjacent its inner end, duct 55 is of slightly reduced diameter. A ball detent 56 is loosely positioned in duct 55 and urged, by a spring 57 interposed between the detent 56 and the inner surface of projectile guide 31, radially inwardly toward the barrel bore. The spring-loaded detent 56 thus tends to prevent a projectile from rolling accidentally out of the forward end of the barrel should the forward end of the gun he tilted downwardly before the projectile is fired.
Slidably mounted in tube 12 to the rear of valve block 20 is a piston 61. A disc-shaped head 62 is secured in the front end of the piston 61 with a pressed fit by means of an integral shank portion 63. Piston head 62 is preferably made of Teflon, and its outside diameter is large enough so that as it slides in tube- 12 it maintains an airtight seal with the inside Wall of tube 12. At its rear end piston 61 has a reduced diameter boss 65. The piston is constantly urged forwardly in tube 12 by a coiled compression spring 66 which fits over the end boss 65 and is interposed between plug 13 and the rear end of the piston. Spring 66 tends to urge the piston axially forwardly in tube 12. The extent to which piston 61 may be moved rearwardly is limited by a stop pin 68 which is secured at one end to the inner face of plug 13, and which extends forwardly therefrom through the coiled spring 66.
Pivotally mounted by means of a pin 71 in a recess in stock 11 adjacent the rear end of tube 12 is the trigger 72. One arm 73 of the trigger carries a sear projection 74 which is adapted to project through a slot 75 in tube 12 into a peripheral groove 76 in piston 61. A coil spring 77 normally urges trigger 72 into piston-engaging position. The forward end of the trigger arm 73 is adapted to engage the bottom of tube 12 to limit the extent to which sear 74 projects into the bore of tube 12. The top of sear 74 is inclined so that when piston 61 is drawn rearwardly in tube 12, the rear portion of the piston may pass freely over the sear 74 by pivoting trigger 72 slightly against the action of spring 77. When the sear registers with the notch 76 in the piston, however, the spring 77 snaps the sear into the notch to lock the piston in its rearward position.
Conventional front and rear sights 78 and 79 are provided on the gun barrel 30 and tube 12, respectively. In use, the gun can be loaded by inserting projectiles B through projectile loading aperture 36 and tilting the gun slightly upwardly so that the balls roll rearwardly of the gun along the guideway defined by tube 12, fiat 51 of barrel 30, and slot 34 in guide 31, to the duct 53. This guideway can hold twenty or more balls, thereby permitting rapid, repeated firing of the gun. An inspection port 81 is provided in tube 12 almost directly opposite duct 53 so that the operator can determine whether or not a B-B is positioned in the bore or the barrel. Port 81 is not large enough to permit a B-B to pass therethrough.
To cock the gun, the barrel 30 is grasped at a knurled part 89 adjacent its forward-end and moved axially rearwardly relative to tube 12. This causes the rear end of valve block to engage the piston head 62 and thereby force the piston rearwardly until sear 74 engages in the notch 76 in the piston. An inspection port 83 is provided in the top of tube 12 so that the operator may see when the piston is positioned in its rear, or cocked position. Thereafter, the barrel is drawn forwardly relative to tube 12 until it assumes the position illustrated in FIG. 1, wherein the forward end of guide 31 abuts the plug 33. The barrel is adapted to be retained in its forward position by means of spring loaded detent 84. Detent 84 is slidably positioned in the forward end of stock 11, and is urged by a spring 87 constantly into slot in tube 12. Screw 32 depresses detent 84 when it slides over it during the movement of barrel 30; and the detent 84 engages the rear of screw 32 to hold the barrel in its forward position after cocking of the piston (FIG. 1). During the rearward movement of piston head 62 air can enter tube 12 through the port 82 in the tube 12. This communicates with the slot 84 in the stock in which the trigger is mounted.
When the trigger is pressed, sear 74 is disengaged from the piston 61 and the spring 66 forces the piston forward compressing the air in the tube 12 between piston head 62 and the valve block 20. The piston head 62 shuts off port 83 during the initial stage of the forward movement of the piston, but the power of valve spring 27 is great enough to keep the valve 23 closed until the air in tube 12 between the forward face of piston head 62 and the rear end of valve block 20 is compressed to a desired degree. It is only then that the air pressure exerted by the compressed air through ports 22 on the valve will open the valve. The compressed air will then flow through the ports 22 to exert its full pressure against the Whole area of the valve head 24 so that valve 23 is suddenly popped open, and the valve stem 25 is moved axially forwardly into the bore of barrel 30. As valve 23 is popped open, the compressed air rushes through ports 22 and the axial bore 26 of the valve against the projectile B in the bore 54, thereby propelling the projectile out of the gun barrel with great force. As the valve is popped open, the stem 25 of the valve will also strike the ball B, which is in the barrel, and help propel this ball out of the barrel. As the valve stem moves forwardly in the bore of the gun barrel it closes ofl. duct 53 so that another ball B cannot drop into the bore until the valve has returned to its rear piston and so that the propelling air will not leak out duct 53. The forward motion of valve stem 25 into barrel 30 is limited by annular shoulder 83 which is formed by the countersink in the rear end of the barrel 30. The air trapped between piston head 62 and valve block 20 cushions and dashpots the forward movement of the piston relative to block 20. After the force of the compressed air has been exhausted, valve spring 28 returns the valve head 24 into engagement with the bottom of the valve block 20 thereby to seal off ports 22 again. When the valve has returned to closed position again, port 53 is cleared and a projectile can drop therethrough into firing position.
From the foregoing, it will be apparent that the applicant has provided a compact air gun in which a high muzzle velocity may be achieved by simple means and without pumping. At the same time he has provided an air gun which can be quickly loaded and quickly fired.
While the invention has been described in connection with a specific embodiment thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention or the limits of the appended claims.
Having thus described my invention, what I claim is:
1. An air gun comprising a hollow cylinder and a tubular barrel connected to said cylinder in axial alignment therewith, a piston slidably mounted in said cylinder, a spring in said cylinder constantly urging said piston forwardly in said cylinder, said piston being movable rearwardly to cocked position, a trigger-operated detent for releasably retaining said piston in its cocked position, said piston when released being urged by said spring forwardly, a pressure-actuated valve disposed between said cylinder and said barrel and operative, when closed, to shut off said cylinder from said barrel, whereby, when said valve is closed, air will be trapped between said piston and said valve and compressed, upon movement of said piston forward, means resiliently holding said valve closed until the pressure of the trapped air has been built up by the piston in its travel to a predetermined air pressure, said resilient holding means thereupon permitting said valve to open, solely under pressure of the compressed air trapped between said piston and said valve, thereby to permit the compressed air to flow into said barrel against a projectile in said barrel to propel the projectile from the barrel.
2. An air gun comprising a tube, a tubular barrel mounted in the front end of said tube in axial alignment therewith, a piston slidably mounted in said :tube, a reciprocable valve block mounted in said tube and connected to said barrel at the rear end thereof, a pressure-actuated valve reciprocable in said block, said valve block having at least one port therethrough for conducting air from said tube to and against said valve, a spring constantly urging said valve to closed position to close said port, a second spring constantly urging said piston toward said valve, said valve block being movable rearwardly with said barrel to engage and urge said piston to cocked position against the resistance of said second spring, said valve block being movable forwardly with said barrel away from said piston to space said block from said piston after said piston is cocked, a trigger-operated detent for releasably retaining said piston in cocked position, said piston upon its release being urged by said second spring toward said valve block to compress air in said tube between said piston and said valve until a sufficient predetermined pressure has been built up to open, solely by the pressure of the air in said tube, said valve against the resistance of the first-named spring, said valve when open, admitting the compressed air into said barrel to propel a projectile from said barrel.
3. An air gun as claimed in claim 2 wherein said barrel has a radial duct through its wall adjacent said valve block for admitting a projectile into firing position in the barrel, and said valve has an axial bore therethrough and includes a stem portion which is operative upon opening of said valve vto slide forwardly into said barrel to block off said duct, said axial bore placing said barrel in communication with said port when said valve is opened, so that the compressed air passes through said port and said axial bore in to said barrel to propel a projectile therefrom.
4. An air gun comprising an elongate tube, a tubular barrel mounted in said rbube in radially spaced, axially aligned relation therewith, an elongate element of generally C shaped cross section mounted in the radial space between said tube and barrel and disposed coaxially about said barrel, said barrel having a longitudinally extending fiat on the peripheral surface thereof extending from a point adjacent its rear end forwardly, said fiat confronting and being longitudinally coextensive with the space between the confronting, elongate edges of said C shaped element, said barrel having a duct through its annular Wall adjacent its rear end and communicating with one end of said flat for admitting a projectile into the bore of said barrel, and said tube having a projectile loading duct through its annular wall adjacent its forward end and confronting the opposite end of said flat, a pressure-actuated valve in said tube controlling communication between the rear end of said barrel and a chamber in said tube, resilient means constantly urging said valve to closed position to shut off communication between said chamber and said barrel, a piston in said chamber movable toward said valve to compress air in said chamber when said valve is closed, said flat on said barrel and said confronting elongate edges on said C shaped element constituting a guideway to guide a projectile from said duct in said tube to said duct in said barrel, and said valve being operable upon the compression of said air in said chamber to a predetermined pressure to open to admit the compressed air into the bore of said barrel to propel a projectile from said barrel.
5. An air gun comprising a tube, a barrel having the rear end thereof connected to the front end of said tube to permit limited reciprocating movement of said tube and barrel relative to one another, a piston slidably mounted in said tube adjacent the rear end thereof, a spring constantly urging said piston forwardly toward the front end of said tube, a pressure-actuated valve connected to the rear end of said barrel and confronting said piston, said valve being operative upon rearward relative movement between said tube and barrel to engage and urge said piston into a cocked position against the action of said spring, a trigger-operated detent for releasably holding said piston in its cocked position, said piston upon its release being urged by said spring toward said valve to compress air in said tube between said piston and valve, resilient means normally holding said valve closed, said valve being operative upon the compression of said air to a predetermined pressure to open against the resist ance of said resilient means thereby to admit the compressed air into said barrel to propel a projectile from said barrel.
6. An air gun comprising, an elongate tube, a tubular barrel, means mounting said barrel in the front end of said tube for axial sliding movement therein, a piston mounted in the rear end of said tube for axial sliding movement therein between a cocked and a forward fired position, respectively, a spring constantly urging said piston forward toward its fired position, a trigger operated detent for releasably retaining said piston in its cocked position, a valve block in the rear end of said barrel to confront said piston and connected to said barre-l for movement therewith axially of said tube, said barrel being manually reciprocable in said tube first rearwardly thereof to cause said valve block to engage and urge said piston to its cocked position, and being manually reciprocable outwardly to space said block axially forwardly away from said piston, when the latter is in its cocked position, and a normally closed pressure-operated valve mounted in said block, said piston upon its release being urged by said spring toward said valve block to compress air between said piston and said valve block to a sufficient predetermined pressure to open said valve, solely in response to the predetermined pressure, thereby to admit the compressed air into said barrel to propel a projectile therefrom.
References Cited by the Examiner UNITED STATES PATENTS 984,072 2/11 Burrows 124--49 2,132,173 10/38 Lefever 124-15 9,633,838 4/53 Seward 124-45 2,881,752 4/59 Blahnik 124-51 FOREIGN PATENTS 571,163 8/45 Great Britain.
RICHARD C. PINKHAM, Primary Examiner. JOHN M. HORAN, DELBERT B. LOWE, Examiners.