BACKGROUND OF THE INVENTION
The present invention relates to a lightweight, high velocity, grenade launcher, and more particularly to a fully automatic grenade launcher which will have a rapid rate of fire.
Various types of guns and launchers have been utilized to fire missiles, such as rockets and grenades. One of the more common type of firing device utilizes a magazine which holds a fixed number of projectiles or shells. One such gun is shown in U.S. Pat. No. 2,380,024, which issued Jul. 10, 1945, to Edward F. Chandler. In this patented gun, the firing unit is comprised of a rotatable magazine and barrel which are supported by frame elements, and the gun is fired by hand cranking, which operates firing and indexing mechanisms.
Another rotary magazine gun is shown in U.S. Pat. No. 2,835,171, which issued May 20, 1958, to George Albert Lyon. A magazine is rotatably mounted to a frame, and the magazine is provided with an indexing track. A gun barrel is reciprocally mounted to the frame, and an indexing pin, which engages the indexing track on the magazine, is attached to the gun barrel. Upon firing of a projectile, the forward motion of the projectile moves the gun barrel forward, thereby compressing a coiled spring, and the forward motion of the gun barrel causes the magazine to be indexed one-half cycle. Upon the projectile clearing the gun barrel, the coiled spring returns the gun barrel to a firing position and the return motion of the barrel indexes the magazine the remaining one-half cycle.
One disadvantage of a magazine gun is the relative low rate of fire. Although the firing rate might be high once the magazine is in position, after the magazine is emptied, it must be removed and a full magazine inserted, and thus the overall rate of fire is greatly reduced. By way of example, U.S. Pat. No. 2,835,171, shows a magazine capable of holding 10 projectiles and thus after firing 10 projectiles the gun must be reloaded by changing magazines.
SUMMARY OF THE INVENTION
The present invention relates to an automatic grenade launcher that fires belt fed rounds of ammunition, with the belt being preferably made of metallic links. The operation of the launcher is novel in that first cam means are operated by the rearward movement of a bolt to index rounds into an upper level position whereupon a round is grasped by a pair of extractors when the bolt goes into battery. As the bolt again moves to the rear, a second cam moves the round down to a lower firing level. A pair of coiled springs are compressed as the bolt moves to the rear and, upon depressing a trigger plunger, these coil springs drive the bolt forward into battery. As the bolt is moving forward into battery, a third cam actuates a firing pin in the bolt thereby firing the round with the link approximately three-fourths of an inch from the base of the round. Just prior to firing the round, the extractors grasp a new round which has been previously indexed into position by the rearward travel of the bolt.
The recoil force from the fired round drives the bolt to the rear and the new round is delinked by the pull of the extractors. Continued rearward travel of the bolt moves the new round downward and forces the empty cartridge case out the bottom of the gun. The gun is recocked during the rearward travel of the bolt and will again fire if the trigger plunger is depressed.
It is therefore a general object of the present invention to provide a lightweight machine gun for firing a high velocity grenade at a high rate of fire.
Other objects and advantages of the present invention will be readily apparent from the following detailed description of a preferred embodiment thereof taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a preferred embodiment of the present invention mounted on a tripod;
FIG. 2 is a top plan view of a preferred embodiment of the present invention;
FIG. 3 is a side view of a preferred embodiment of the present invention;
FIG. 4 is a top view similar to FIG. 2 of the drawings, partially broken away to show various working parts;
FIG. 5 is an end view of the embodiment shown in FIG. 2 of the drawings, with the end plate being removed to show inner parts;
FIG. 6 is a partial top view showing a feeding mechanism;
FIG. 7 is a sectional view showing an indexing mechanism;
FIG. 8 is a sectional view taken on line 8-8 of FIG. 7;
FIG. 9 is a side view of a vertical cam;
FIG. 10 is a view, partly in section, showing a trigger and sear mechanism;
FIG. 11 is a front view of a bolt assembly;
FIG. 12 is a side view of a bolt assembly;
FIG. 13 is a sectional view taken on line 13-13 of FIG. 12;
FIG. 14 is a sectional view taken on line 14-14 of FIG. 11;
FIG. 15 is a sectional view taken on line 15-15 of FIG. 11;
FIG. 16 is a sectional view taken on line 16-16 of FIG. 12; and
FIG. 17 is a partial sectional view showing a bolt and receiver assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1 of the drawings, there is shown a launcher 11 of the present invention mounted on a standard military tripod 12. The manner of mounting, however, is optional and many different mounts might be used depending on the manner in which the launcher is to be utilized. An ammunition can 13 is shown attached to tripod 12, and a flexible ammunition belt 14 is provided to transfer rounds from ammunition can 13 to launcher 11. An adjustable rear sight 15 and a fixed front sight 16, both of which are well known in the firearm art, are provided to facilitate the aiming of the launcher during firing.
Referring now to FIGS. 2, 3, and 4 of the drawings, a barrel 17 is threadedly attached to the a receiver 18 and a front cover assembly 19 is pivotally attached to receiver 18 by means of shaft 21. A slidable latch 22 is attached to back cover assembly 23, and spring means 24 are provided to keep latch 22 biased in a forward locking position to secure front cover assembly 19 during firing of launcher 11.
Front cover plate 19 is pivotally attached to receiver 18 in order to facilitate the loading of rounds into feeder chamber 25. As best shown in FIGS. 3, 4, 6, and 7 of the drawings, feeder chamber 25 is positioned above the center of barrel 17 and the rounds being loaded are supported by base plate 26 which is provided with a groove 27 through which links 30 holding the rounds together travel. A first pair of pawls 28 and 29 are pivotally connected to receiver 18 and pawls 28 and 29 extend through slots in base plate 26. Pawls 28 and 29 are spring loaded by spring 31 which permits pawls 28 and 29 to be depressed when a round is moved into feeder chamber 25. After the round passes pawls 28 and 29, the pawls are biased upward by spring 31, thereby holding the round against moving back out of feeder chamber 25. Likewise, a second pair of pawls 32 and 33 are pivotally attached to receiver 18 and are spring biased and function similar to pawls 28 and 29. A spring biased pressure plate 34 is slidably attached to the front wall 35 of feeder chamber 25 and pressure plate 34 pushes against the nose of the rounds as they are being fed into chamber 25 so as to keep the rounds in alignment and in position to be picked up by extractors. A resilient bumper 36 is also attached to wall 35 and provides a cushion for the nose of the round that is being picked up by extractors.
Referring specifically to FIGS. 4, 7, and 8 of the drawings, there is shown an indexing mechanism 20 for feeding rounds into feeder chamber 25. A pair of push pawl 37 and 38 are pivotally supported by shaft 39 to outer shuttle 41 and spring 42 is provided to bias pawls 37 and 38 in a pushing position, as shown in FIG. 7 of the drawings. Shaft 39 and spring 42 permit the pawls to pivot over an adjacent round on a return cycle of the indexing mechanism 20. An inner shuttle 43 is slidably attached to outer shuttle 41. An inner spring housing 44 is secured, as by screws, to inner shuttle 43 and an outer spring housing 45 is secured, as by screws, to outer shuttle 41. A spring guide 46 is threadedly attached to outer housing 45 and spring guide 46 extends into inner spring housing 44 with a spring 47 surrounding and being supported by spring guide 46. Housings 44 and 45 and spring 47 secure shuttles 41 and 43 together, and yet, relative movement between shuttles 41 and 43 is possible in the event that there is any jamming of the rounds being fed into chamber 25. A pin 48 is threadedly attached to inner shuttle 43 and pin 48 engages with a drive mechanism which causes indexing mechanism 20 to be reciprocated.
Referring specifically to FIG. 7 of the drawings, three grenade rounds 51, 52, and 53 are shown in feeder chamber 25. Round 51 is in position to be picked up by extractors on a bolt, and round 51 is being maintained in exact pickup position by back stop 50 which holds round 51 against pawls 32 and 33. As back stop 50 is spring biased, it serves as a shock absorber when the rounds are indexed. When round 51 is moved back by the extractors on the bolt, round 51 is delinked from round 52, and pawls 28 and 29 prevent round 52 from being pulled out of feeder chamber 25 by the weight of the other rounds which have not yet moved into feeder chamber 25. Push pawls 37 and 38, as shown in FIG. 7 of the drawings, are in position to move round 52 into its pickup position, however, this cannot be done until round 51 has been cleared. Accordingly, as will be more fully hereinafter described, push pawls 37 and 38 are delayed until round 51 moves rearwardly and downwardly a sufficient distance so that rounds 51 and 52 will not interfere with each other. When indexing mechanism 20 moves toward barrel 17, pawls 37 and 38 push round 52 over pawls 32 and 33, which are depressed and, when round 52 clears, pawls 32 and 33 spring up again. As rounds 52 and 53 are linked together, movement of round 52 pulls round 53 along, and round 53 depresses pawls 28 and 29 which, likewise, spring up again after round 53 clears.
Referring now to FIGS. 4, 11, and 12 of the drawings, a horizontal cam 54 has an upward extending stud 55 which is pivotally connected to the back cover assembly 23. Cam 54 has a straight portion 56 on its outer end and a curved portion 57 between straight portion 56 and stud 55. As best shown in FIGS. 11 and 12 of the drawings, cam 54 is T-shaped in cross section with the lower portion being engaged between followers 58 and 59, which are rotatably mounted to the top of bolt assembly 61.
A rocker arm 62 is pivotally connected to the front cover assembly 19 by means of stud 63 and locking ring 64. An elongated slot 65 is provided near one end of rocker arm 62 and an open-ended slot 66 is provided at the other end of rocker arm 62. Slot 65 is engageable with pin 67 which is attached to horizontal cam 54 and open-ended slot 66 is engaged with pin 48 on indexing mechanism 20. As rocker arm 62 is attached to the front cover assembly 19 and also to indexing mechanism 20, it can be seen that indexing mechanism 20 is pivoted about shaft 21 when front cover assembly 19 is raised. When front cover assembly 19 is closed, such as after loading rounds into feeder chamber 25, it is necessary that slot 65 in rocker arm 62 again engage with pin 67. As can best be seen in FIGS. 11 and 17 of the drawings, bolt 61 moves in a straight path in receiver 18, however, the engagement of horizontal cam 54 with followers 58 and 59 causes rocker arm 62 to be pivoted as the bolt moves both forward and rearward within receiver 18 and which operation will be more fully explained hereinafter.
Referring now to FIGS. 11 through 17, bolt assembly 61 is provided with a pair of pivotal extractors 71 and 72, which are spring biased in a closed position, as shown in FIGS. 11 through 17. Extractors 71 and 72 are each provided with tapered surfaces 73 and 74, respectively, which serve to open or pivot, extractors 71 and 72 when these extractors engage a round in feeder chamber 25. Bolt 61 is provided with a longitudinal slot 75 that extends from the top surface to about midway through the bolt, and slot 75 provides a passageway which permits bolt 61 to reciprocate relative to vertical cam 76 which extends downwardly into the path of travel of bolt 61, as best seen in FIG. 5 of the drawings.
Vertical cam 76 is provided with a top flange 77, which attaches to back cover assembly 23, and front flange 78, which attaches to the sides of receiver 18. Vertical cam 76 is provided with a cam surface 79 and it is the function of cam surface 79 to move the round, which has been picked up by extractors 71 and 72, downwardly so that it is aligned with barrel 17. Referring to FIGS. 9 and 12 of the drawings, round 81, which is shown in phantom, will be cammed downwardly be vertical cam 76 as bolt 61 moves to the rear and, as round 81 moves downwardly, cartridge case 82 will be ejected through opening 83 in the bottom of receiver 18, and round 81 will move into the position previously occupied by cartridge case 82. In order to properly align round 81 with the center of barrel 17 and also with firing pin 84 in bolt 61, a pair of snubbers 85 and 86 are pivotally attached to the face of bolt 61 and are biased toward firing pin 84 by springs 87. As best shown in FIGS. 11 and 15 of the drawings, a round stop 88 is also pivotally attached in a slot 89 in the face of bolt 61 and spring 91 biases stop 88 outwardly. When round 81 is cammed downwardly by vertical cam 76, round stop 88 is pushed inwardly, however, when round 81 clears stop 88, spring 89 biases round stop 88 outwardly and snubbers 85 and 86 push round 81 against the bottom edge of round stop 88 thereby properly positioning the round with respect to barrel 17 and firing pin 84.
Firing pin 84 is provided with a reduced diameter portion 92 which is engageable with keeper 93. Keeper 93 is spring biased by spring 94 against firing pin 84 to retain firing pin 84 in a cocked position. Release shaft 95, which is biased outwardly by spring 96, has a notched portion 97 which is engageable with the top tapered edge 98 of keeper 93. Release shaft 95 is provided with a slot 99 through which pin 101 extends to retain release shaft 95 inside bolt 61 when firing pin 84 is in an uncocked position, as the force of spring 96 would tend to drive release shaft 95 outside of bolt 61.
A cocking lever 102 is pivotally connected to bolt 61 by shaft 103 and one end of cocking lever 102 engages in a slot 104 in firing pin 84. As best shown in FIGS. 11 and 17 of the drawings, bolt 61 travels on rails 105 and 106, and the outer extending end of cocking lever 102 slides in groove 107 in rail 106. Rail 106 has an opening 108 which permits cocking lever 102 to be pivoted about shaft 103. A firing pin trip 109 is attached by screws 120 to the right side of receiver 18, as shown in FIG. 17 of the drawings, and as bolt 61 moves forward, release shaft 95 is depressed inwardly by firing pin trip 109. The inward movement of release shaft 95 causes keeper 93 to be depressed which, in turn, permits firing pin spring 110 to drive firing pin 84 forward and the tang 111 of firing pin 84 is driven through a hole 112 in cover plate 113 to strike the primer of a round, if a round is present. In the event of an accidental depression of release shaft 95, such as might be caused by shock, cocking lever 102 which is slidable in groove 107, prevents firing pin 84 from moving forward unless, of course, the end of cocking lever 102 is adjacent opening 108. At this position, however, any round present would be in battery and any premature firing would be prevented. It can thus be seen that cocking lever 102 serves as a safety device to prevent any premature firing of the weapon. The prime function, however, of cocking lever 102 is to recock firing pin 84 when bolt 61 recoils. The outer end of cocking lever 102 engages rail 106 as bolt 61 moves to the rear thereby causing cocking lever 102 to pivot about shaft 103. This moves firing pin 84 to the rear relative to bolt 61 whereupon keeper 93 engages firing pin 84 to retain firing pin 84 in a cocked position.
When bolt 61 moves to the rear on rails 105 and 106, bolt springs 114 and 115 are compressed, and it is the energy of these springs that drive bolt 61 forward when the weapon is to fire. The forward ends of bolt springs 114 and 115 extend into bores 116 and 117, respectively, in bolt 61, and the rear ends of bolt springs 114 and 115 are supported by plunger assemblies 118 and 119. As best shown in FIG. 10 of the drawings, each plunger assembly is comprised of a housing 121 and a plunger 122 which is biased outwardly by spring 123 which is positioned inside housing 121. A rounded end guide 124 is provided on the end of plunger 122 to facilitate the movement of the bolt springs onto the plunger assemblies. When the ends of bores 116 and 117 engage the ends of end guides 124, further rearward movement of bolt 61 causes plunger 122 to telescope inside housing 121 thereby compressing spring 123. Upon forward movement of bolt 61, spring 123 causes plunger 122 to be extended and thus provide longer supports for bolt springs 114 and 115 than would be possible if each plunger assembly were a stationary rod.
In order to limit the reward travel of bolt 61, a pair of shock absorbers 125 are attached to back plate 126. Each shock absorber is comprised of a plurality of curved washers 127 which are supported on a mandrel 128. In order to allow sufficient rearward travel of bolt 61, a pair of bores 131 and 132 are provided on the back side of bolt 61 and, in operation, shock absorbers 125 pass into the bores in bolt 61.
Referring now to FIG. 10 of the drawings, there is shown a trigger mechanism for firing the weapon, and, for purpose of illustration, there is shown mechanism for firing the weapon both manually and electrically. A trigger sear 133 which is pivotally mounted to trigger housing 134 by pin 135, is biased upwardly by spring 136 into a locking position with sear 137 which is attached to the bottom of bolt 61. A trigger button 138 is slidably attached to back plate 126 and trigger button 138 is engageable with toggle plate 139 which is pivotally mounted by pin 141. A shaft 142 is positioned between the bottom of toggle plate 139 and the top of the outer end of trigger sear 133. Spring 143 is provided to bias shaft 142 against toggle plate 139. A safety lever 144 is pivotally attached to receiver 11 and, as shown in FIGS. 3 and 10 of the drawings, when lever 144 is in the "safe" position, lever 144 prevents trigger sear 133 from being rotated about pin 135. By rotating lever 144 approximately 90° in a counterclockwise direction, the weapon can be fired.
A solenoid 145 can readily be attached to the bottom of receiver 18 with the plunger 146 of solenoid 145 being attached to cantilever arm 147 of trigger sear 133. Upon energization of solenoid 145, plunger 146 moves downwardly in a manner well known in the art, and trigger sear 133 is rotated thereby disengaging trigger sear 133 from sear 137 which is attached to the bottom of bolt 61.
In order to facilitate aiming and firing of launcher 11, a pair of hand grips 148 and 149 are attached to back plate 126. In order to facilitate cocking of launcher 11, a cocking handle 151 is attachable in hole 153 in the side of bolt 61, and an elongated slot 152 is provided in receiver 18 to permit movement of handle 151 of handle 151 when bolt 61 travels inside receiver 18.
In loading launcher 11, bolt 61 is first pulled to the rear by grasping and pulling cocking handle 151 until sear 137 on bolt 61 is engaged and held by trigger sear 133. The front cover assembly 19 is then opened by sliding latch 22 to the rear and raising cover assembly 19, which will pivot about shaft 21. When cover assembly 19 is raised, the slot 65 in rocker arm 62 is disengaged from pin 67 in horizontal cam 54.
With cover assembly 19 open, grenades are loaded by hand into feeder chamber 25 and, as shown in FIGS. 6 and 7, three rounds 51, 52, and 53 are in position, with round 51 being biased against pawls 32 and 33 by back stop 50. Back stop 50 acts as a shock absorber during firing when the rounds are quickly indexed into their next position, and also the biasing force applied to round 51 keeps round 51 in exact position for pickup by extractors 71 and 72 on bolt 61. Rounds 51, 52, and 53 are still linked together, however, pawls 28 and 29 are up and against round 52 and pawls 32 and 33 are up and against round 51, and these two pair of pawls prevent the linked ammunition from sliding out of feeder chamber 25. Cover assembly 19 is then closed and, at the time of closing, the indexing mechanism 20 should be in a position such that push pawls 37 and 38 are in contact with round 51 as this will permit slot 65 in rocker arm 62 to engage with pin 67 in horizontal cam 54. If this procedure is not followed, the launcher will jam.
Assuming manual firing, bolt 61 is allowed to go forward by depressing trigger button 138 which causes trigger sear 133 to disengage sear 137 on bolt 61 and the energy from bolt springs 114 and 115 drive bolt 61 forward. As bolt 61 travels forward, followers 58 and 59 on bolt 61 cause horizontal cam 54 to be pivoted about its fixed cam stud 55, and this movement of cam 54 causes rocker arm 62 to be pivoted about its fixed stud 63 and thus indexing mechanism 20 is returned to its reload position. This reload position is shown in FIG. 7 of the drawings, with push pawls 37 and 38 being in contact with round 52. As bolt 61 goes forward into battery, extractors 71 and 72 snap onto the rim of round 51.
Bolt 61 is again moved to the rear by pulling on cocking handle 151. At the beginning of the rearward movement of bolt 61, followers 58 and 59 are engaged with straight portion 56 of horizontal cam 54 which, in effect, is a dwell, and bolt 61 recoils approximately 3 inches before indexing mechanism starts moving round 52 toward backstop 50. This dwell period permits round 51 to be moved out of position so that rounds 51 and 52 will not interfere with each other. When round 51 starts its movement to the rear, round 51 is delinked from round 52 and as round 51 is moved to the rear, cam surface 79 of vertical cam 76 moves round 51 downwardly with respect to bolt 61. As round 51 moves downwardly, round stop 88 is pivoted or pushed back into slot 89 of bolt 61, thereby compressing spring 91 and, when round 51 clears stop 88, spring 91 pivots stop 88 outwardly. Round 51 is moved downwardly by cam 76 and is engaged by snubbers 85 and 86, which provide an upward bias against round 51 thereby pushing round 51 against the bottom edge of round stop 88. It can thus be seen that snubbers 84 and 85 and round stop 88 position round 51 so that it is properly aligned with respect to firing pin 84.
When followers 58 and 59 engage curved portion 57 of horizontal cam 54, rocker arm 62 is pivoted by cam 54 and indexing mechanism 20 moves round 52 over against backstop 50. Round 53 is pulled along and replaces round 52 in its previous position.
During the rearward travel of bolt 61, the outer end of cocking lever 102 engages or strikes rail 106 causing cocking lever 102 to pivot about shaft 103 thereby causing firing pin 84 to compress firing pin spring 110. Keeper 93 engages the reduced diameter portion 92 of firing pin 84 and firing pin 84 is retained in a cocked position. Bolt 61 moves rearwardly until sear 137 on bolt 61 engages with trigger sear 133. Upon release of cocking lever 151, trigger sear 133 prevents any forward travel of bolt 61. The rearward travel of bolt 61 causes bolt springs 114 and 115 to be compressed. Launcher 11 is now in fire position and if for any reason the gun is not to be fired immediately, safety lever 144 should be turned so that safety lever 144 prevents the depression of trigger sear 133.
When it is desired to fire the weapon, safety lever 144 is turned approximately 90° in a counterclockwise direction. Assuming manual firing, trigger button 138 is depressed which causes toggle plate 139 to pivot about pin 141 and toggle plate 139 depresses shaft 142 which, in turn, depresses trigger sear 133 and causes sear 137 on bolt 61 to disengage from trigger sear 133. Bolt springs 114 and 115 drive bolt 61 forward, and followers 58 and 59 actuate cam 54 and rocker arm 62 to return indexing mechanism to its ready position. As indexing mechanism 20 moves away from barrel 17, push pawls 37 and 38 pivot about shaft 39 so that they can pass over round 53 which is in a ready position and is the next round to be pushed over against backstop 50.
Round 51, which is being carried forward by bolt 61, enters barrel 17 and link 30, which is approximately in the middle of round 51, is pushed back toward the rim of round 51. Just prior to the firing of round 51, extractors 71 and 72 engage round 52. While bolt 61 is moving forward, cocking lever 102 is sliding in groove 107 of rail 106 and is constrained from pivoting about shaft 103. As best shown in FIG. 17 of the drawings, when bolt 61 is near barrel 17, so that a substantial length of round 51 has entered barrel 17, cocking lever 102 is adjacent an opening or separation 108 in rail 106 and, in essence, cocking lever 102 becomes released from its constraint. At this position of cocking lever 102, release shaft 95 is engaging firing pin trip 109, which has a tapered leading edge. Movement of release shaft 95 compresses spring 96 and also movement of shaft 95 depresses keeper 93 and firing pin spring 110 drives the tang 111 of firing pin 84 into the primer of round 51. Round 51 fires and the recoil force drives bolt 61 to the rear.
The same sequence of events is repeated as when the bolt 61 was pulled to the rear manually, except, however, at the start of the rearward movement of bolt 61, both the empty cartridge case of round 51 and the full round 52 are being carried by bolt 61. When round 52 is cammed downwardly by vertical cam 76, round 52 expels the empty cartridge case of round 51 through opening 83 in the bottom of receiver 18.
As best shown in FIG. 6 of the drawings, a resilient bumper 36 provides a cushion when bolt 61 moves forward and snaps onto a rim of a round to be picked up. Also pressure plate 34 facilitates the alignment of rounds being fed into feeder chamber 25.
It can thus be seen that the present invention provides a new and novel weapon for launching grenades. Obviously 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.