US 3695246 A
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United States Patent lFilippi et al.
 PNEUMATIC MACHINE GUN WITH PHOTO CELL INTERRUPTED CIRCUIT  Inventors: Ernest A. filippi; Jack B. Watson; Larry E. Hughes, all of Newhall,
 Assignee: The United States of America as represented by the Secretary of the Navy 22] Filed: June 10, 1971  Appl. No.: 151,681
 US. Cl. ..124/1l, 124/32, 124/48, 124/51 R, 124/30 R, 35/25, 273/106 R  Int. Cl. ..F41f U112  Field of Search..l24/l l, 32, 48, 50, 51 R, 51 A; 35/25; 89/33 E  References Cited UNITED STATES PATENTS 2,837,076 6/1958 Koci et a1 .124/51 R X 2,845,055 7/1958 Collins et a1 ..124/ll 3,492,742 2/ 1970 Aldrich et a1 ..35/25 1 Oct. 3, 1972 Primary Examiner-Richard C. Pinkham Assistant Examiner-R. T. Stouffer Attorney-Richard S. Sciascia, John W. Pease and Harvey A. David ABSTRACT A pellet firing pneumatic machine gun wherein a toothed wheel carries pellets from a hopper and conveyer assembly to a position adjacent one end of a barrel through which the pellets are propelled by an air blast from a solenoid valve, the periodic energization of which is effected by a photo-cell exposed to a light source, wherein the light source is placed on the opposite side of the periphery of the pellet delivering wheel from the photo-cell such that upon rotation of the wheel, the teeth thereof act to interrupt light from the light source falling on the photo-cell. In addition,- a pellet slitting device mounted on the other end of the barrel, wherein the device includes adjustable blades which score the skin of dye containing pellets shot from a gun to render the pellets more frangible upon impact.
4 Claims, 6 Drawing Figures PATENTEDBBIB I972 SHEET 1 OF 4 INVENTORS ERNEST A. F/LIPPI JACK B. WATSON LARRY E. HUGHES 49%?- fwd ATTORNEY 'PATENTEDIIBTB I912 Y 3.695.246 swine er 4 Ll l I06 2 I22 |o4 80 us H2 I CONTROL C 3 CIRCUIT 2 H4 82 l 8 c g 3 FIG. 4
' INVENTORS ERNEST A.FILIPPI JACK B. WATSON LARRY E. HUGHES ijfl i AT TORNE Y PATENTEUUCT 3 i972 SHEET 3 BF 4 INVENTORS ERNEST A. FILIPP/ JACK B. WATSON LARRY E. HUGHES -@Ma/ ATTORNEY PATENTEDncra m SHEET u 4 INVENTORSI LARRY E. HUGHE ATTORNEY BACKGROUND OF THE INVENTION This invention relates to pneumatic machine guns or pellet propellers useful for training purposes, and more particularly to an improved propeller capable of firing dye filled gelatin pellets which burst upon impact against trainee to provide a lasting and realistic indication of hits.
A variety of pneumatic machine guns have been proposed heretofore and generally share an arrangement by which pellets are conveyed from a magazine and placed, one at a time, in position to be propelled through a barrel by pressurized air released by a valve in timed relation to the arrival of the pellet in position to be fired. The timed relation has in most instances been determined by rotary cam means geared to the pellet conveyer means and mechanically actuating the valve or switch means in the case of a solenoid valve. An alternative has been a reciprocating air motor which controls the pellet delivery and valve operation.
In most of the foregoing arrangements the timing has been determined by mechanical arrangements, particularly cams and followers which are subject to wear and change .of adjustment which adversely affect the nicety of timing which is needed for proper operation. Other timing arrangements such as have depended upon a build-up of pressure through a restriction, are limited to applications where the repetition rate is very low, e.g. in propelling baseballs for batting practice.
Prior art pneumatic machine guns have had as their principal purpose the training of personnel in operation and aiming at targets. There has been lacking a suitable machine gun or pellet propeller which could be used to provide simulated machine gun fire from a nest or building to be attacked by trainees. In this regard, it is considered desirable to fire dye containing pellets with sufficient velocity as to burst and mark trainees, when hit, and yet be relatively safe so as not to cause injury to the trainees.
SUMMARY OF THE INVENTION.
. With the foregoing in mind, it is one important object of the invention to provide an improved pneumatic propeller for pellets of the type utilizing a motor driven notched feeder wheel for carrying pellets from a supply to a position adjacent the barrel, and solenoid controlled valve for releasing a blast of air at the proper time to drive the pellet through the barrel, the improved propeller being characterized by novel valve actuating timing means.
Another important object of the invention is the provision, in an improved propeller of the foregoing character, of means for slitting or scoring the walls of a dye containing pellet as it passes from the propeller so that bursting of the pellet is assured upon impact even though the impact velocity is sufficiently low to render it unlikely that physical injury of a person hit would occur.
Other objects and advantages of the invention will become apparent from the following description of a presently preferred embodiment when read in conjunction with the accompanying sheets of drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a pellet propeller embodying the invention with portions broken away to reveal other portions;
FIG. 2 is a diagrammatic plan view of the pellet propeller;
FIG. 3 is a diagrammatic perspective illustration of the propeller;
FIG. 4 is a simplified electrical diagram illustrating the control system of the propeller;
FIG. 5 is a sectional view on an enlarged scale taken along line 4-4 of FIG. 1 and illustrating the pellet slitter forming part of the propeller; and
FIG. 6 is a sectional view taken substantially along line 6-6 of FIG. 5.
DESCRIPTION OF THE PREFERRED EMBODIMENT In the form of the invention illustrated in the drawings and described hereinafter, there is provided a pellet propeller 10 which is operable from a source of pressurized air and a source of electric power such as volts AC. The pellet propeller 10 comprises a housing 12 formed of sheet aluminum or other suitable material and including 12a, 12b, side walls 12c, 12d, a tap wall 12c, and a bottom wall 12f. Within the housing is a frame 14 comprising a base plate 14a spaced above the bottom wall 12f by channel members 16, and various upright and transverse members 14b, 14c, 14d, Me, and 14f on which components described hereinafter are mounted.
These components include a barrel 20 mounted parallel to the base plate 14a and extending from adjacent the rim of a feeder wheel 22 toward the end wall 12b where it terminates in a pellet slitting device 24. The feeder wheel 22 which has a plurality of evenly spaced teeth defining pellet receiving recesses in the periphery thereof is fixed to a shaft 26 and is adapted to be rotated during firing of the propeller by an electrical motor 28. To this end the motor 28 is coupled through a gear reducer 30 to a pneumatic clutch 32 which is normally disengaged. The clutch 32 is actuated by pressurized air via line 34 when a solenoid valve 36 is energized, the latter being connected via line 38 to receive air brought to the propeller from a suitable source to a connection 40 at end wall 12a.
Mounted above the feeder wheel 22 is a pellet hopper and conveyer assembly, generally indicated at 44. This assembly is driven in consonance with the feeder wheel 22 by a chain 46 leading around a sprocket 48 on shaft 26, an idler sprocket 50 mounted on frame member 14d, and a sprocket 52 fixed to a shaft 54 extending from the hopper and conveyer assembly 44. As is best illustrated in FIG. 3, the assembly 44 comprises as part thereof, a moving belt conveyer 55. A feed tube 56 having a vertical passage therethrough is mounted beneath the assembly 44 and terminates over the upper reach of the feeder wheel 22. The feed tube 56 receives pellets from the belt 55 of the assembly 44 and deposits them one by one in the recesses in the periphery of the feeder wheel as it rotates.
The hopper assembly 44 advantageously further comprises means such as belts 57 carried by upper and lower rollers 58a and 58b, the lower rollers being driven by suitable miter gears (not shown) from a chain 59 and associated sprockets. The purpose of the belts 57 is to agitate the pellets P within the hopper assembly 44 to prevent the formation of arches of pellets carried by the belt 55. The hopper may additionally include heating means such as electrical resistance heating strips under the control of a thermostat to prevent the pellets from becoming hard or brittle under cold conditions and possibly injuring a trainee.
Approximately one quarter of the rim portion of the feeder wheel 22 is covered by a fender or shroud 60 which serves to prevent the pellets P from falling from the recess in the feeder wheel rim during their travel from the hopper and conveyer assembly 44 to the point of firing.
Mounted in alignment with the inner end of the barre] 20, and on the other side of the path of travel of the feeder wheel 22, is a solenoid valve 62, which valve is connected via line 64 to an accumulator 66. Referring to FIG. 2, the accumulator 66 is connected via line 68, an oiler 70, line 72, a regulator 74, and line 76 to the high pressure air connection 40. The regulator 74 serves to reduce the high pressure input to a lower, more constant value. The oiler 70, serves to introduce a small quantity of oil into the air supplied to the valve 62 to lubricate the pellet and ease its travel through the barrel 20. The regulator 74 and oiler 70 are conventional commercially items and need not be described in detail.
Mounted approximately 180 from the solenoid valve 62, around the feeder wheel 22, are a light source 80 and a photocell 82 between which is the path of travel of the peripheral teeth 22a of the feeder wheel. The photo-cell 82 forms part of the electrical control circuitry of the propeller which will be discussed more fully as the specification proceeds. The photo-cell 82, the solenoid valves 36 and 62, are connected by electrical cables 90, 92, and 94, to a box 100 containing control circuit means later discussed with reference to FIG.
The propeller 10 is provided with an electrical cable 102 for connection to a source of A.C. power, conveniently 1 15 volts. A power switch 104 is mounted on the end panel 12a as is a firing switch 106. These switches, the power cable 102, the motor 28, and the logic means are suitably interconnected as by electrical cables 108, 110.
Referring now to the diagram of FIG. 4, the A.C. power supply is represented as lines L1 and L2. The switch 104 controls the supply of A.C. power via line 112 to the motor 28 such that upon closing the switch 104, the motor will begin to run, which is the normal condition even though the propeller is not firing. The light source 80 is conveniently energized from a transformer 114 energized via switch 104.
The firing switch 106 provides A.C. line current via lines 116 to a control circuit 120 for the firing solenoid valve 62, and via line 122 to the clutch operating solenoid valve 36. The photo-cell 82 is connected to the control circuit 120 which, in its simplest form, can comprise means such as trigger circuitry responsive to output of the photocell above a selected threshold to effect energization of the firing solenoid valve 62. Preferably, however, the control circuit 120 also includes circuitry such as that disclosed in US. Pat. No. 3,418,494 which will assure that the solenoid valve 62 will be come energized at the beginning of the half A.C. cycle, either positive or negative, following the reaching of the threshold, and will persist only for that half cycle. This provides for crisp, positive, and uniform action of the firing solenoid valve 62.
Referring to FIGS. 5 and 6, the pellet slitter 24 comprises a generally flat circular body having an externally threaded central boss 132 which extends through an opening in the end panel 12b of the propeller housing and is adapted to receive a cap to ex clude dirt and moisture when the propeller is not in use The slitter 24 is conveniently secured to the end panel 12b by screws 134 extending through the body 130. The boss 132 has a central bore 136 the diameter of which matches that of the barrel 20. A large counter bore 138 receives one end 142 of a barrel adapter 144 which has a radial flange 146 secured to the body 130 as by screws 148.
The adapter 144 is externally threaded and is received in the correspondingly internally threaded end of the barrel 20.
The body 130 has four radial bores 150 extending from the periphery thereof inwardly as far as the counter bore 138. The outer portions of the bores 150 are counterbored as at 152 and threaded as at 154. The bores 150 communicate with the bore 136 through slots 156 which are adapted to receive knife blades 160. The blades 160 are fixed to radially movable blade holders each having a stem portion 162 slideable in the bore 150 and larger diameter head portion 164 in the counterbore 152. A compression spring is disposed in each counterbore 152 and resiliently urges the blade holder and blade 160 outwardly. An adjusting screw 172 is threaded into each of the counterbores 152 and bears against the head portion 164 of the corresponding blade holder. The screws 172 may be turned to adjust the amount of the knife blades 160 which will protrude into the bore 136 and may be secured in adjusted position by lock nuts 176. With the knife blades fully retracted, the pellets are not affected. However, the blades may be extended into the bore 136 as shown to make four shallow slits in the pellet skin as it leaves the barrel. Such slitting causes the pellets to rupture more easily upon impact, thereby reducing the pain inflicted on persons hit.
Obiously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
What is claimed is:
1. In a pellet propeller operable from a source of A.C. electrical power and a source of compressed air and including a motor, a toothed wheel adapted to be driven in rotation by said motor for conveying pellets from storage means to a firing position adjacent a barrel, and firing solenoid valve means for releasing a blast of compressed air to fire each pellet, the improvement comprising:
a light source disposed on one side of the periphery of said wheel;
photo-cell means mounted on the opposite side of the periphery of said wheel such that light from said source falling on said photo-cell means is periodically interrupted by teeth of said wheel and said photo-cell provides an electrical output which fluctuates at the frequency of the passing of said teeth; and circuit means responsive to said fluctuations to effect energization of said solenoid valve means in timed relation to rotation of said wheel. 2. A pellet propeller as defined in claim 1, and further comprising:
pneumatic clutch means between said motor and said wheel; clutch operating solenoid valve means connected between said source of compressed air and said clutch means; firing switch means operable to energize said clutch solenoid valve means to cause said clutch means to complete connection of said motor to said wheel to initiate firing. 3. A pellet propeller as defined in claim 2, and further comprising:
pelter slitter means mounted on said barrel and comprising blade means extending into the path of said pellets and operative to slit the pellets as they are fired.
4 A pellet propeller as defined in claim 3 and wherein said slitter means comprises:
a body having a central bore in axial alignment with said barrel, said body having a plurality of radial bores extending inwardly toward said central bore but terminating short thereof, a plurality of radially extending slots each connecting one of said radial bores with said central bore;
a plurality of blades each disposed in one of said slots; A
a plurality of blade holders each having one of said blades fixed thereto and each disposed for radial movement in said radial bores;
spring means resiliently urging said blade holders and blades radially outwardly from said central bore; and
screw means disposed in said radial bores and operative to advance or retract said blade holders and blades with respect to said central bore.