Elastic powered compressed air gun

An elongated horizontal barrel, transfer tube and cylinder are provided in vertically laterally stacked relation with the barrel disposed uppermost and the cylinder disposed lowermost. Closure structure is provided for the rear end of the barrel and the rear end of the barrel and transfer tube are in closed communication with each other while the forward ends of the transfer tube and cylinder are in closed communication with each other. The closure structure is shiftable to a position opening the rear end of the barrel and the rear end of the barrel may receive a blow dart therein after which the rear end of the barrel is closed. A piston is freely slidable within the cylinder and elastic tubing structure is provided for yieldingly biasing the piston forwardly within the cylinder and cocking structure is provided whereby the piston may be manually displaced rearwardly in the cylinder against the biasing action of the force structure. Finally, trigger actuatable retaining structure is provided for releasably retaining the piston in a rearmost displaced position within the cylinder.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a dart gun including a barrel in which a dart may 
be received and through and from which the dart may be projected by 
compressed air supplied to the breech end of the barrel. The gun includes 
a cylinder having a piston slidable therein, retractable to a cocked 
position and yieldingly biased toward one end of the cylinder by elastic 
surgical tubing. The one end of the cylinder is communicated with the 
breech end of the barrel and the barrel breech end includes a closure 
therefor in the form of a retractable bolt to provide access to the barrel 
breech end for the insertion of a dart thereinto. 
2. Description of Related Art 
Various different forms of fluid pressure powered guns heretofore have been 
provided including some of the general structural and operational features 
of the instant invention. Examples of these previously known forms of guns 
are disclosed in U.S. Pat. Nos. 1,310,745, 2,069,821, 2,214,224, 
2,713,859, 3,142,293, 3,552,372, 4,212,285 and Pat. Nos. Des. 159,040 and 
201,366. 
SUMMARY OF THE INVENTION 
This invention relates to an air gun in the form of a rifle wherein a 
retractable piston is slidably mounted within a cylinder and is yieldingly 
biased toward one end of the cylinder through the utilization of tensioned 
surgical tubing sections. A barrel is provided having muzzle and breech 
ends and a transfer tube is disposed between and parallels the barrel and 
cylinder and communicates the forward end of the cylinder toward which the 
piston is yieldingly biased with the rear breech end of the barrel. An 
oscillatable and longitudinally shiftable breech bolt is provided for 
removably closing the breech end of the barrel and may be shifted to a 
rearwardly displaced open position to provide access to the breech end of 
the barrel for the purpose of enabling a dart to be inserted therein. The 
breech bolt includes a laterally projecting handle and cam structure for 
retaining the breech bolt in a forward displaced position closing the 
breech end of the barrel upon swinging movement of the handle to either 
side of the barrel from a center position thereof. The rear end of the 
cylinder includes a centrally apertured end wall through which a piston 
rod connected to the piston is slidably received and the rear end of the 
rod includes a handle thereon whereby the rod may be retracted rearwardly. 
The gun includes trigger structure for releasably retaining the piston rod 
in a rearwardly retracted position and the rod is yieldingly biased 
forwardly in the cylinder through the utilizaton of surgical tubing member 
sections having one set of corresponding ends anchored to a forward stock 
portion of the gun and a second set of corresponding end portions anchored 
relative to the handle on the rear of the piston rod. 
The main object of this invention is to provide a readily operable gun 
which may be used to propel darts therefrom at high velocity. 
Another object of this invention is to provide a dart gun in accordance 
with the preceding objects and which utilizes air under pressure as the 
motive force for propelling a dart through and from the barrel of the gun. 
Still another important object of this invention is to provide a dart gun 
in accordance with the preceding objects and wherein the compressed air 
for operating the gun is produced by air compressed in one end of the 
cylinder as a piston slidable in the cylinder is forced from the other end 
of the cylinder toward the one end thereof. 
A further object of this invention is to provide a dart gun including 
tensioned surgical tubing operatively connected between the stock of the 
gun and the air pressure producing piston for yieldingly biasing the 
piston toward the end of the cylinder in which air is compressed. 
Still another object of this invention is to provide a dart gun including a 
simple tube-type sight. 
A final object of this invention to be specifically enumerated herein is to 
provide a dart gun in accordance with the preceding objects and which will 
conform to conventional forms of manufacture, be of simple construction 
and easy to use so as to provide a device that will be economically 
feasible, long lasting and relatively trouble free in operation. 
These together with other objects and advantages which will become 
subsequently apparent reside in the details of construction and operation 
as more fully hereinafter described and claimed, reference being had to 
the accompanying drawings forming a part hereof, wherein like numerals 
refer to like parts throughout.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now more specifically to the drawings, the numeral 10 generally 
designates the dart gun of the instant invention. The dart gun 10 includes 
a barrel 12, a pneumatic cylinder assembly referred to in general by the 
reference numeral 14 and a transfer tube 16 clamped between opposite side 
portions 18 and 20 of a body or stock assembly referred to in general by 
the reference numeral 22, the opposite side portions 18 and 20 being 
secured together through the utilization of transverse fasteners 24. 
The barrel 12, cylinder assembly 14 and transfer tube 16 are held against 
shifting relative to each other between the opposite side portions 18 and 
20 in parallel relation and with the barrel 12 uppermost and the cylinder 
assembly 14 lowermost. The stock assembly 22 includes a hand grip 26 which 
extends downwardly from the rear of the stock assembly 22 and a trigger 
guard 28 is clamped between the opposite side portions 18 and 20 and 
encloses a trigger 30 pivotally supported from the stock assembly 22 as at 
32. The trigger assembly is received through a laterally opening notch 
formed in a vertically disposed and reciprocal piston rod retainer 34 
reciprocally mounted between the opposite side portions 18 and 20 for 
movement in a substantially vertical plane and an expansion spring 35 is 
operatively connected between the lower end of the retainer 34 and a lower 
portion of the interior of the handgrip 26 and yieldingly biases the 
retainer 34 in a downward direction. The upper end of the retainer 34 
extends upwardly through an opening 36 provided therefor in the rear 
portion of the cylinder 38 of the cylinder assembly 14 and includes a 
laterally opening notch 40, see FIG. 4, through which a piston rod 42 
reciprocal in the cylinder 38 extends. 
The forward end of the piston rod 42 has a piston 44 mounted thereon 
provided with a cupped annular seal 46 sealingly and slidingly disposed 
within the cylinder 38 and the forward end of the rod 42 includes an 
upwardly opening notch 48 formed therein with which the notched upper end 
portion of the retainer 34 is engageable to retain the piston 42 in a 
rearwardly displaced "cocked" position. 
The rear end of the piston rod 42 extends through a centrally apertured 
rear wall 50 secured over the rear end of the cylinder 38 and the rear 
extremity of the rod 42 includes a handle 52 supported therefrom including 
finger engageable portions 54 projecting oppositely outwardly fron the rod 
42. In addition, the rear of the handle 52 includes a rearwardly opening 
transverse notch 56 formed therein and a coiled compression spring 58 is 
disposed about the rod 42 intermediate the handle 52 and the rear wall 50 
to cushion the handle 52 against sudden impact with the rear wall 50 as 
the rod 42 is rapidly displaced forwardly. 
The underside of the body 22 includes a pair of longitudinally spaced 
downwardly opening transverse notches 60 formed therein and the bight 
portions 62 of a pair of generally U-shaped anchors 64 are seated within 
the notches 60 and have the curved portions 66 of their oppositely 
laterally outwardly and rearwardly inclined arms 68 passed about pairs of 
opposite side laterally outwardly projecting abutment pins 70 carried by 
the opposite side portions 18 and 20. 
A pair of elastic surgical tubing members 72 are provided and one pair of 
corresponding ends of the tubing members 72 are telescoped over and thus 
anchored to the free ends of one pair of corresponding arms 68 and the 
other pair of corresponding ends of the tubing members 72 are telescoped 
over and thus anchored relative to the free ends of the other pairs of 
arms 68. The tubing members 72 are thus arranged in a U-shaped pattern and 
the bight portions of the tubing members 72 are received through a 
protective sleeve 74 seated in the rearwardly opening notch 56, an elastic 
band 76 being disposed about the opposite ends of the tubing sleeve 74 
immediately forward of the portions 54 of the handle 52. The plastic 
sleeve serves as a safety member preventing totally free rearward snapping 
of one of the tubing members 72 in the event one front end thereof slips 
from its anchor arm 68 and the elastic band 76 serves to maintain the 
bight portions of the tubular members 72 and the protective sleeve 74 
seated in the notch 56 and also to prevent free rearward snapping of one 
end of the sleeve and the attendant tubing member ends in the event both 
tubing member ends should break. 
The forward end portion of the barrel 12 includes an upstanding forward 
sight 78 and the rear end portion of the barrel 12 is enclosed within an 
outer tube or sleeve 80 sealed relative to the barrel 12 at its forward 
end as at 82 and sealed relative to the rear end of the barrel 12 as at 
84, see FIG. 3. Further, a forward cap 86 sealingly receives the forward 
ends of the cylinder 38 and transfer tube 16 therein and includes a 
passage 88 therein by which communication is established between the front 
end of the cylinder 38 and the front end of the transfer tube 16. An 
upstanding tubular fitting 90 establishes communication between the rear 
end of the transfer tube 16 and the interior of the rear end of the tube 
80 rearward of the seal defined between the rear ends of the tube 80 and 
the barrel 12 as at 84. Accordingly, rapid movement of the piston 44 
forwardly in the cylinder 38 will cause compressed air to pass from the 
forward end of the cylinder 38, through the passage 88, rearwardly through 
the transfer tube 16 and upwardly through the fitting 90 into the rear end 
of the barrel 12. 
The upper rear portion of the stock assembly 22 includes a boss 92 through 
which a front-to-rear extending bore 94 is formed and the bore 94 has a 
bearing sleeve 96 mounted therein which slidably and oscillatably receives 
the rear end of a cylindrical breech bolt 98 therein. The breech bolt 98 
includes a laterally outwardly projecting handle 100 and the opposite side 
portions 18 and 20 include inverted U-shaped cam bars 102 and 104, 
respectively, supported therefrom forward of the boss 92. Further, the 
forward end of the bolt 98 includes a resilient seal plug 99 mounted 
thereon seatingly and sealingly engageable with the otherwise open rear 
end of the tube 80 disposed rearward of the fitting 90 and the bolt 98 
projects forward of the plug 102 and terminates in a forwardly tapering 
forward extremity 101 for a purpose to be hereinafter more fully set 
forth. 
A pair of upstanding front and rear sight mounts 106 and 108 are clampingly 
supported from opposing notched portions of the opposite side portions 18 
and 20 and the sight mount 106 has a horizontal forwardly tapering bore 
110 formed therethrough paralleling the barrel 12. The sight mount 108 
includes a larger diameter bore 112 formed therethrough and the front and 
rear ends of a tubular sight 114 are received through the bores 110 and 
112. Further, the mount 108 includes a compression spring 116 yieldingly 
biasing the rear end of the tube 114 upwardly and a set screw 118 
threadingly supported therefrom by which the rear end of the sight tube 
114 may be downwardly adjusted. 
In operation, the handle 52 is grasped and pulled rearwardly in order to 
rearwardly retract the piston 44 to the "cocked" position thereof 
illustrated in FIG. 8 of the drawings with the upper notched end of the 
retainer 34 engaged in the notch 48 at the forward end of the rod 42 
immediately rearward of the piston 44. Thereafter, or prior to having 
"cocked" the piston 44, the bolt 98 is rotated by handle 100 to a position 
with the handle 100 projecting upwardly and the bolt 98 is rearwardly 
displaced to the position thereof illustrated in FIG. 6 with the handle 
100 disposed rearwardly of one of the cam brackets 102 and 104. 
Thereafter, a dart such as dart 120 is inserted into the rear end of the 
tube 80 and the rear end of the barrel 12 with the rearwardly opening 
cup-shaped tail 122 of the dart 120 positioned in the rear extremity of 
the barrel 12. Then, the handle 100 may be raised to the intermediate 
position thereof and forwardly displaced toward the forward ends of the 
cam bracket 102 and 104 and thereafter swung downwardly to a position in 
front of either bracket 102 or bracket 104. This will cam the plug 99 into 
tight sealed engagement with the rear end of the tube 80 and will allow 
the forward extremity 101 of the bolt 98 to slightly forwardly displace 
the dart 120 within the barrel 12 to the position thereof illustrated in 
FIG. 3. Then, upon exerting a rearward pull on the trigger 30, the 
retainer 34 will be upwardly displaced against the biasing action of the 
expansion spring 34 in order to release the rod 42 whereby the tensioned 
tubing members 72 will rapidly forwardly displace the rod 42 and thus the 
piston 44 in the cylinder 38. This will cause air to be compressed within 
the forward end of the cylinder assembly 14, to pass through the passage 
88 and then rearwardly through the transfer tube 16 and upwardly through 
the fitting 90 into the rear of the tube 80 and the rear of the barrel 12 
for propelling the dart 120 rapidly forwardly through and from the barrel 
12. 
Inasmuch as the handle 100 may be pivoted to either side of the stock 
assembly 26, the gun 10 may be conveniently used by either a right-handed 
person or a left-handed person. 
Further, it is deemed apparent that more than two tubing members 72 could 
be utilized to drive the piston 44 forwardly in the cylinder 38 and that 
the power of the gun 10 thus may be increased, if desired. On the other 
hand, one of the tubing members 72 may be removed in order to reduce the 
power of the gun 10. 
The foregoing is considered as illustrative only of the principles of the 
invention. Further, since numerous modifications and changes will readily 
occur to those skilled in the art, it is not desired to limit the 
invention to the exact construction and operation shown and described, and 
accordingly, all suitable modifications and equivalents may be resorted 
to, falling within the scope of the invention.