US 2758586 A
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United States Patent O AIR GUN Ciro R. Scalingi, Plymouth, Mich., assignor to Daisy Manufacturing Company, a corporation of Michigan Application August 18, 1953, Serial No. 374,949
1 Claim. (Cl. 124-415) This invention relates generally to air guns and, more particularly, to a novel and improved piston and air tube construction for such guns, and constitutes an improvement over my copending application, Serial Number 245,316, filed September 6, 1951, and relating to improvements in Air Gun (not abandoned).
'Ihe conventional air gun is provided with a cylinder in its barrel within which a spring-actuated piston reciprocates upon the cooking and firing of the gun. Extending forwardly from the piston is an air tube through which air, compressed by the piston, flows at a velocity so as to propel the projectile from the gun barrel when the piston is actuated by its spring. The air is compressed between the piston and an abutment or cylinder end member, generally in the form of a leather washer having a central aperture therein through which the air tube extends into a shot tube or chamber wherein the projectile to be propelled is disposed. The forward motion of the piston within the cylinder is arrested by the leather washer which it abuts at the end of its stroke.
The most satisfactory piston and air tube constructions devised before the date of my aforementioned copending application were of the type where the piston is formed with a cylindrical metal core having a flanged forward end, and the air tube is provided with a flanged or upset end. The two flanged portions are held in solid metal-to-metal axially aligned engagement by a disk or metal stamping surrounding the upset portion of the air tube and connected with the piston. In this type of construction, the sheet metal stamping is, by necessity, positioned on the piston so that it engages and abuts the leather washer forming the abutment or forward end of the cylinder, upon firing of the gun. Suitable apertures are provided in either the air tube adjacent the piston or in the disk or metal stamping which allows the compressed air to llow into the air tube. In practice it has been found that the pistons and air tubes so constructed are subject to mechanical failures after repeated iirings of the gun. The constant striking of the piston against the leather washer causes a fatiguing of the air tube at its junction with the piston so that the air tube will break at that point. Actual tests indicate that this failure will normally occur after the gun has been red approximately 6,000 times. Furthermore, the continued engagement or abutting of the sheet metal stamping or disk and the leather washer causes destruction of the leather washer after the gun has been red about 10,000 times. Still further, if the air tube and the piston are not in exact alignment with the shot tube and the aperture in the washer, the air tube will tend to buckle or bend upon its reciprocation, causing a fatiguing of the air tube and a slowing down of the speed of the piston. This diiculty may be attributed to the fact that the air tube is mounted rigidly in the piston and may not move laterally during the reciprocating movement of the piston.
The above-described diculties of the prior art constructions were overcome by the piston and air tube construction of my aforementioned copending application in ICC which the air tube is resiliently mounted in a rubber piston or the like, thus avoiding the destructive jarring caused by the solid metal-to-metal contact between the air tube and piston, and permitting limited lateral lnovement of the air tube as might be occasioned by any misalignment with the shot tube and the aperture in the washer. However, while the resiliently mounted air tube overcame the difficulties of the past constructions, it has been found that when any of the shot jams in place, so as to make the air tube stick in the shot tube, a new diiculty is presented in that the air tube may be pulled out of the piston during the next cooking of the gun. Actual tests reveal such failure will occur if a cooking force of from 40 to 50 pounds is exerted on the plunger of a gun in which the air tube is jammed.
It is, therefore, an object of this invention to overcome the aforementioned dilliculties of the prior art constructions, by the provision of a new and improved air tube and piston construction.
It is a further object of this invention to provide a piston and air tube construction for air guns in which the air tube is resiliently mounted in the piston, thus avoiding the destructive jarring caused by a solid metalto-metal contact between the air tube and the piston, and permitting limited lateral movement of the air tube, as might be occasioned by any misalignment, without fatiguing the air tube and its connection with the piston and causing breakage thereof.
It is another object of this invention to provide a piston and air tube construction for air guns in which the air tube extends through a resilient piston and is secured to a rigid air gun plunger by a transverse pin so as to take all the stress off the piston and to prevent the air tube from being pulled out of the piston when the gun is cocked.
Another object of this invention is to provide a piston having a resilient frontend, so that the cylinder end member or washer will not be readily destroyed.
A still further object of this invention is to provide an improved piston and air tube construction which is positive in operation, extremely durable in use, and convenient of manufacture.
These and other objects of this invention will become apparent from the following detailed description, especially when taken in conjunction with the accompanying drawing, wherein:
Figure l is a longitudinal View partially in section and partially in elevation, of an air gun embodying the features of the invention, the gun being uncooked;
Fig. 2 is an enlarged view of the structure illustrated in Fig. l, taken within the dot-dash line 2 of Fig. l; and
Fig. 3 is a perspective view of an air tube embodying the features of the present invention.
This invention is designed and adapted for use with the conventional type air rifle including a cylinder 10 supported in a barrel housing l2 in the usual manner and in which a plunger head or piston 14 carrying an air tube 16 at its forward end reciprocates. The piston 14 is carried in the forward hollow end of an elongated plunger 18 provided with a clip 20 at its rearward end. A coil spring 22 surrounds the plunger 18 and is disposed between a pin 24, which connects the piston and air tube to the plunger, and spring abutment means 26 which is mounted on the frame of the gun and against which the spring 22 is compressed when the gun is cocked. The gun is cocked by the downward movement of the rear portion of a lever 28 which moves the front portion 30 of the lever upwardly `and rearwardly` The lever 28 is pivotally connected with the gun frame at 32 and the aforementioned movement of the lever causes the front portion 30 to contact clip 20 and move it rearwardly so as to engage the clip 20 with a sear 34 on the uppermost 3 part of the `trigger 36, thus holding the plunger in the cocked position.
The piston 14 is preferably of a one-piece construction of heat and oil resistant buna rubber, formed in a molding operation, and is provided with a main truncated conical portion 38 which snugly lits the inside of the cylinder 10, and a verticallyapertured cylindrical projecting portion 40 of less diameter than portion 38 extending co-axially rearwardly from the main portion 38. The projecting portion 40 of piston v14 is disposed within the hollow forward end of the plunger 18 and is held therein by a pin 24 extending through the vertical aperture 42 in portion 40 and oppositely facing apertures 44 in the plunger 18. A suitable washer 45 is provided between the rearward side of the piston portion 38 and the front end of the rplunger 18. A circular groove 46 is disposed on the front end of the main portion 38 of the piston 14, providing an annular shoulder 48 which may expand laterally when compressed. The groove 46 thus gives the front end of the piston a greater degree of resiliency.
The air tube 16 is provided with a vertical port 50 adjacent the front end of the piston 14, and an upset rearward end 51, having a pair of `.abutting tiat portions 52 and 53 with an aperture 56 therethrough. The flat portions 52 and 53 are located by means of the flat tab 54 in the projecting portion 40 of the piston 14 so as to have aperture 56 aligned with the vertical aperture 42 in the piston 14. The air tube 16 is made from a suitable iiat workpiece which has been notched on one end to form the flat tab 54. As is best seen in Fig. 3, the workpiece is then rolled so as to locate the seam 57 in the middle of the tab 54. The vertical port 50, at portions 52 and 53, and aperture 56 ,are then formed in one stroke by a die punching operation, the workpiece being `located in the die by the tab 54 so that the aperture 56 will be formed with an equal thickness of material on the sides designated S9 and 61. The rubber piston 14 is preferably molded with the axial aperture 63 formed to match the shape of the rearward end 51 of the air tube 16. The aperture 42 in the piston 14 may be provided therein by any suitable method as by drilling. The air tube 16 is mounted in the piston 14 by inserting the rearward end 51 of the air tube 16 into the forward end of the axial aperture 63 and then forcing the air tube inwardly into the proper position. It will be appreciated that the air tube 16 may be mounted in the piston 14 by other suitable methods, and that the piston 14 may be made of other suitable resilient materials.
The forward wall of the cylinder is formed by a washer 58 having an aperture 60 through which the air tube 16 extends and snugly .interiits The washer 5S, which seals the forward end of the cylinder 10, is illustrated as being made of leather, but other suitable materials may be used. Communicating and aligned with the aperture 60, of the washer 58, is .a shot tube 62 into which the air tube 16 further extends and reciprocates. When the gun is fired, the piston moves forward in the cylinder 10 compressing the air between it and the washer 58. The compressed air enters the port 50 and ows out of the air tube 16 into the shot tube 62 in order to propel a projectile disposed therein from the gun.
In the construction set forth, the ilat portions 52 and 53, the tab S4, and a rearward portion of the air tube 16 are completely enclosed and surrounded by the resilient piston 14. The pin 24 provides a metal-to-metal engagement between the `air gun plunger 18 and the air tube 16 which operates to take all the stress off the resilient piston 14. Accordingly, the piston 14 serves mainly as a sealing medium for the cylinder 10. If the projecting portion 4G of the resilient piston 14 is so disposed within the end of the plunger 18 that the air tube 16 is not aligned with the shot tube 62, the air tube may move laterally during its reciprocation without it fatiguing. Furthermore, as the piston 14 strikes the washer 58, the rubber or resilient material surrounding the air tube rearward end 51 cushions and prevents it from rapidly fatiguing. It will be seen that the forward face of the piston 14 is so formed so as to lessen the destructive effect it has on the washer 58. In addition to the normal resiliency that the face of the piston 14 would have, the annular groove 46 permits a greater compression of the forward face of the piston upon its striking the washer 53. Thus, the piston bounces olf the washer 58 rather than embedding itself therein. Actual tests have revealed that the improved air tube and piston construction set forth will withstand a cooking force of from 400 to 500 pounds before failing, by having the air tube pulled from the piston.
While only one specific embodiment of my invention has been illustrated and described herein, it will be readily appreciated by those skilled in the art that numerous modifications and changes may be made without departing from the spirit of the invention.
What is claimed is:
In an air gun, the combination of a plunger recipro cable in said gun and having a hollow forward end portion, said forward end portion having a transverse aperture therein, a piston formed of resilient material and having a main body portion adapted to fit within and engage the wall of a cylinder, a reduced cylindrical portion extending rearwardly from said main body portion and being disposed within said hollow forward end of said plunger, said piston reduced portion having a transverse aperture therein in alignment with said plunger aperture, said piston having an axial aperture therethrough, an air tube having the rear end thereof flattened and provided with a transverse aperture therethrough, said attened end being disposed in said piston `axial aperture so that said air tube aperture is disposed in alignment with the apertures in said plunger hollow forward end portion and said piston reduced cylindrical por tion, and a rigid retaining member extending through said `apertures so as to retain said air tube, said plunger and said piston in an assembled relationship while permitting limited lateral movement of said air tube in said resilient piston.
References Cited in the tile of this patent UNITED STATES PATENTS 1,259,463 De Fir Mar. 12, 1918 1,869,600 Loomis Aug. 2, 1932 2,132,173 Lefever Oct. 4, 1938 FOREIGN PATENTS 589,550 Great Britain June 24, 1947