Spiral drum magazine with elongated magazine clip and single piece last round follower
REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of application Ser. No. 920,046, filed Oct. 16, 1986 now U.S. Pat. No. 4,745,842. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a magazine into which rounds of ammunition can be loaded, and which can be connected to an automatic rifle. More particularly, the invention relates to a drum magazine having a drum with spiral path therein which is followed by the rounds of ammunition, a rotor for moving the ammunition in series along the spiral path to the drum outlet opening, a clip magazine connected to the outlet of the drum, and a last round follower which urges the last round of ammunition out of the opening of the spiral drum and on through the clip magazine toward the weapon. 
     BACKGROUND OF THE INVENTION 
     In the use of automatic fire arms where a plurality of rounds of ammunition are to be fed in a short period to the chamber of the weapon, it has been common to use elongated clips which store the rounds of ammunition, and a spring is used to bias the rounds of ammunition toward the chamber of the weapon. Where it is desirable to have a larger number of rounds of ammunition available than can be accommodated by a conventional clip magazine, drum magazines have been utilized which store the rounds of ammunition in a circular arrangement beneath the weapon, and the rounds are fed in series along a circular path toward the breech of the weapon. Further, drum magazines having spiral paths for the rounds have been used whereby the rounds are stored in a concentric circular arrangement within a drum and follow a spiral path so as to be fed in series to the weapon. In both the plain drum and spiral drum magazines a last round follower is utilized for pushing the last round of ammunition out of the drum and on into the chamber of the weapon. 
     While drum magazines have been utilized to hold large numbers of rounds of ammunition, some of the weapons cannot accommodate a drum magazine because of the shape of the weapon. For example, weapons having trigger guards or stock components adjacent the breech of the weapon sometimes do not provide enough room for attachment of the drum magazine. Thus, it would be desirable to utilize a drum magazine in combination with a conventional elongated clip magazine, whereby the clip magazine is attached to the weapon and the drum magazine is attached to the clip magazine, with the drum magazine feeding rounds of ammunition to the clip magazine and with the clip magazine transferring the rounds of ammunition on to the weapon. This arrangement would support the drum magazine in spaced relationship from the weapon so that the components of the weapon would not interfere with the mounting of the drum magazine to the weapon, and enable the combination drum and clip magazines to accommodate more rounds of ammunition. However, a satisfactory last round follower has not been developed in the prior art which is capable of not only urging the last round from the drum magazine out of its opening but also entirely thorugh the elongated clip magazine to the weapon. 
     SUMMARY OF THE INVENTION 
     Briefly described, the present invention comprises a storage magazine for rounds of ammunition to be fed to an automatic weapon which includes a drum magazine having a spiral path formed therein for placement of rounds of ammunition, and an elongated clip magazine mounted to the outlet opening of the drum magazine, a rotor within the drum magazine for moving the rounds of ammunition along the spiral path, and a single piece last round follower that not only moves the last round of ammunition out of the drum magazine but also urges the last round of ammunition along the length of the clip magazine on into the breech of the weapon. 
     The spiral drum magazine includes a rotor that has a pair of parallel, concentric rotor plates maintained in parallel relationship by intermediate connecting pins In the disclosed embodiment of the invention the last round follower is positioned generally between the rotor plates and is pivotably connected at one of its ends to an outer peripheral portion of the rotor plates. The distal end of the follower includes a protrusion which is of a size and shape approximately the same as a single round of ammunition, and which extends into the spiral path of the drum and which pushes the last round of ammunition from the drum into the elongated clip magazine. 
     The last round follower is arranged so that its protrusion which engages the last round of ammunition can change directions of movement from its spiral path in the drum to a radial direction so it can move on through the clip magazine, thus pushing the last round of ammunition through the clip magazine to the weapon. A spacer is positioned in the clip magazine and includes a leaf spring which maintains rounds of ammunition in proper alignment within the clip. 
     Thus, it is an object of this invention to provide an improved drum magazine for providing large numbers of rounds of ammunition to a weapon, which has the capability of moving the rounds of ammunition through an intermediate elongated clip magazine that extends between the drum magazine and the weapon. 
     Another object of this invention is to provide a reliable magazine for accommodating large numbers of rounds of ammunition, and which is light weight and has the ability to rapidly feed the ammunition to its weapon. 
     Another object of this invention is to provide a spiral drum magazine for a weapon which includes an elongated clip magazine that attaches directly to the weapon, with a drum magazine attached to the distal end of the clip magazine, and with a last round follower that functions to move the last round of ammunition from the drum magazine longitudinally through the clip magazine into the chamber of the weapon. 
     Another object of this invention is to provide a combination of a spiral drum magazine and an elongated clip magazine for attachment to a weapon, which holds a large number of rounds of ammunition and which reliably feeds the rounds of ammunition first in a spiral path within the drum magazine and then along a longitudinal path extending between the drum magazine to the weapon. 
     Other objects, features and advantages of this invention will become apparent upon reading the following specification, when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective illustration of the spiral drum magazine. 
     FIG. 2 is an exploded perspective view of the spiral drum magazine, showing the internal components. 
     FIG. 3 is an end view of the internal components of the drum of the magazine. 
     FIG. 4 is an exploded side cross-sectional view of the spiral drum magazine. 
     FIGS. 5, 6, 7 and 8 are rear views of the spiral drum magazine, with FIG. 5 showing the magazine fully loaded, and with FIGS. 6, 7 and 8 showing progressive conditions of the magazine as the rounds of ammunition are fed therefrom. 
     FIG. 9 is a cross-sectional view of the rectilinear clip magazine, showing the last round follower extended from the rotor of the drum magazine into the clip magazine. 
    
    
     DETAILED DESCRIPTION 
     Referring now in more detail to the drawings, in which like numerals indicate like parts throughout the several views, FIG. 1 illustrates the spiral drum magazine 10 which includes a drum 11 having a cylindrical outer wall 12, front wall 14 (FIG. 3), and door 15 which functions as a rear wall. Door 15 is attached to drum 11 by hinge 16 at the bottom of the door and the drum, and L-shaped latches 18 and 19 are mounted to the outer upper surface of drum 11 and pivot over door 15 into frictional engagement therewith so as to hold the door 15 in its closed position. A crank 20 is pivotably mounted to door 15 at its center portion, so as to enable the user of the magazine to wind the torsion spring 21 (FIG. 2). An elongated clip magazine 22 is mounted to the upper portion of drum 11. Clip magazine 22 is to be connected to the lower breech opening of the weapon (not shown). 
     As illustrated in FIGS. 2 and 3, drum 11 includes an inner cylindrical housing 24 which accommodates torsion spring 21, with the housing 24 being concentric with drum 11. Cap 25 is sized and shaped to fit about and to close inner cylindrical housing 24. The outer portion of spiral torsion spring 21 is fastened to inner cylindrical housing 24 by screw 26 (FIG. 4), and the inner end 28 of the torsion spring 21 is formed at a right angle. Spring axle 29 extends through the front aperture 30 of drum 11, with the front aperture 30 being concentric with respect to the drum. Spring axle 29 includes an end cap 31 at one end and an inwardly tapered annular flange 29a formed on its opposite end. The spring axle is tubular with longitudinal slots 32 formed therein, and with an internal shoulder 34 adjacent cap 31. When spring axle 29 is inserted through front aperture 30, the right angle end portion 28 of the torsion spring 21 is received in one of the slots 32. Washer 35 is positioned over the inwardly protruding end of spring axle 29, and the central opening 36 of cap 25 is positioned about the inwardly protruding portion of spring axle 29. 
     Spring latch assembly 38 comprises latch 39 and coil compression spring 40 attached to the latch. Coil compression spring 40 is sized and shaped so as to be telescopically received in the longitudinal opening of spring axle 29, and the latch is also slid into the slots 32, with the wings 41 of the latch protruding out through the slot 32. 
     Rotor 44 is approximately disk shaped and is of a diameter slightly smaller than the inside diameter of drum 11. Rotor 44 comprises a pair of spaced rotor plates 45 and 46 which are maintained in aligned, parallel relationship by a plurality of spacer pins 48. 
     The rotor plates 45 and 46 of rotor 44 are substantially identical and are parallel, coaxial, and circumferentially aligned. Each rotor 45 and 46 includes a central hub 49 (FIG. 5), radially extending arms 50 extending at 90° intervals from hub 49 intermediate ring 51 and a plurality of dividers 52 which extend generally radially outwardly from intermediate ring 51. A central opening 54 is formed in each hub 49 of each rotor plate 45 and 46, so that the hubs can be telescopically mounted about spring axle 29. Positioning slots 55 are formed at 90° intervals about the inner edge of central opening 54 of rotor plate 46 for the passage therethrough of latch 39. The central opening 54 of the other rotor plate 45 is surrounded by circular ratchet 58 (FIG. 4), with the teeth 59 of the ratchet extending inwardly between rotor plates 45 and 46 for engagement with latch 39. 
     Latch plunger assembly 60 comprises outer cylindrical spool 61 having spiral threads 62 formed on the outer surface of its inner end, and collar 64 formed at its other end, with lever protrusions 65 extending radially outwardly from opposite sides of collar 64. Annular lip 61a is formed in the longitudinal bore of outer cylindrical spool 61, plunger 66 is telescopically received within the longitudinal bore, and coil compression spring 68 biases the plunger 66 to its retracted position by engagement between annular lip 61a and the end cap 70 of the plunger Annular recess 64a is formed in collar 64 adjacent cylindrical spool 61 and has inwardly tappered outer wall 64b. The threads 62 are received in the internal threads 63 at the distal end of spring axle 29 and the distal end of spring axle 29 is received in the annular recess 64a with tapered surface 29a of the spring axle being in firm engagement with inwardly tapered outer wall 64b of the annular recess. The engagement of the distal end of the spring axle 29 and the annular recess 64a  effectively prevents the spring axle 29 from spreading apart when the latch plunger assembly 60 is threaded tightly into the spring axle 29. With this arrangement, the spring axle 29, rotor 44, washer 35, cap 36 and latch 39 are held together, with the rotor 44, spring axle 29 and plunger assembly being rotatable with respect to the drum 11. 
     When the end cap 70 is pressed against the bias of spring 68, the plunger will protrude from outer cylindrical spool 61 and engage latch 39, pushing latch 39 against the bias of its coil compression spring 40, thus moving latch 39 out of engagement with the teeth 59 of ratchet 58. This effectively disconnects rotor 44 from coil torsion spring 21, allowing the spring and its axle 29 to freely rotate to an unbiased position while rotor 44 remains still. When cap 70 is released so that its coil compression spring moves the plunger back within the confines of its outer cylindrical spool 61, latch 39 moves under the bias of its spring 40 back into engagement with the teeth 59 of ratchet 58, thus locking the rotor 44, latch 39 and coil torsion spring 21 together, so that when the rotor is rotated about the spring axle 29, the spring axle will rotate in unison with the rotor and wind against the bias of coil torsion spring 21. This causes a rotational bias to be applied to rotor 44. 
     A rotary cleat 71 (FIG. 2) is mounted to the inside surface of door 15 and is rigidly connected to crank 20 that is mounted to the outside surface of the door. Rotary cleat 71 includes tines 72 with spaces formed therebetween, such that when the door 15 is moved to its closed position, the tines 72 will straddle the lever protrusion 65 of latch plunger assembly 60, so that when crank 20 is rotated, the rotary cleat will rotate latch plunger assembly 60. This causes latch 39 to rotate spring axle 29, thereby winding torsion spring 21. As latch 39 rotates in a clockwise direction, it slips over the sloped portions of the ratchet teeth 59 of rotor 44, so that rotor 44 is not required to rotate. When the spring has been rotated to the proper tension as desired by the operator, the spring will bias rotor 44 in the opposite, counterclockwise direction (FIGS. 5-8). 
     As illustrated in FIGS. 5-8, the dividers 52 of rotor 44 diverge in width from their inner portions to their outer radial portions forming spaces 74 between the dividers 52. The spaces 52 have generally parallel sides and are slanted slightly in a direction opposite to the direction of travel of the ammunition along the spiral path 81. Further, the outer edge portion of most of the dividers includes a semi-circular recess 76. 
     As illustrated in FIG. 3, drum 11 includes a spiral divider 78 that is mounted to front wall 14, with the spiral divider 78 extending from a position adjacent inner cylindrical housing 24 progressively slightly more than three revolutions within drum 11, and terminating at its connection 79 to the cylindrical outer wall 12 at a position just beyond the outlet opening 80 of the drum. With this arrangement, spiral divider 78 defines a spiral path 81 internally of drum 11, into which rounds of ammunition can be loaded and which are followed by the rounds of ammunition as the rounds are moved within the drum 11 by rotor 44. The spiral path 81 extends in a generally spiral fashion around the interior of the drum for approximately four revolutions such that four layers of ammunition may be loaded into the magazine. 
     As illustrated in FIGS. 5-8, rotor 44 is placed in overlying relationship with respect to spiral path 81. Rounds of ammunition 82 are placed in drum 11 by inserting the rounds in the spaces 74 between the dividers 52 of the rotor 44, with each round of ammunition also protruding inwardly beyond the rotor 44 into the spiral path 81 formed by the spiral track 78. Also, additional rounds of ammunition 84 are inserted in the semicircular recesses 76 at the outer peripheral portion of most of the dividers 52, with these rounds of ammunition also extending into the spiral path 81. It will be noted that the larger recesses 74 between the dividers are deep enough so as to span four concentric portions of the spiral path 81 of the drum, whereas most of the outer recesses 76 register with only the two outermost portions of the spiral path 81. 
     As shown in FIGS. 2, 4 and 5-8, the last round follower 85 is connected to a peripheral portion of rotor 44. Last round follower 85 is formed as a single piece that is connected at one of its ends by a pivot pin 90 to a pair of dividers 52A and 52B of rotor 44, by the insertion of pivot pin 90 through the aligned openings 91A and 91B of the dividers 52A and 52B and through the hinge element 92 of last round follower 85. Thus, the last round follower 85 is freely pivotable about pivot pin 90 and the outer portion of rotor 44. It will be noted that the distal end portion 101 of last round follower 85 is formed with oppositely extending lateral protrusions 102 and 103. 
     The last round follower 85 has a width smaller than the space between rotor plates 45 and 46 of rotor 44, except for protrusions 102 and 103. Thus, the last round follower 85 will freely move between rotor plates 45 and 46 with the protrusions 102 and 103 extending laterally beyond rotor plates 45 and 46. 
     As illustrated in FIG. 5, it will be noted that the last round follower 85 extends radially inwardly of the rotor 44 from its pivot pin 90, with the protruding end portions 103, 104 resting at the innermost edge of the space 74A between dividers 52A and 52B. The last round follower extends radially inwardly so as to avoid contact with the rounds 82 of ammunition positioned between the dividers 52C and 52D. The protrusion 102 projects laterally inwardly into the innermost portion of spiral path 81. 
     As illustrated in FIGS. 1 and 9, the elongated magazine clip 22 is of conventional outside shape, being of conventional width and depth and of the desired length. This permits the assembly to be mounted to a convention weapon. However, the inner portion of the magazine clip 22 is formed so as to accommodate the rounds of ammunition in a single row, instead of in the conventional staggered row arrangement. Partition 108 is mounted to a side wall 109 of magazine clip 22 so as to make the passage 110 through the magazine clip 22 narrower. Also, a leaf spring 89 is mounted to the lower portion of the partition 108 to urge the ammunition against the inside of clip wall 114. The lower opening 111 of clip 22 is mounted to drum 11 so that it registers with the outlet opening 80 of the drum, and a guide 112 is mounted to the inside wall of of drum 11 and includes a pair of downwardly protruding finger elements 115 (FIG. 4) which protrude into drum 11 and into the outer portion of spiral path 81, with the space between fingers 115 being slightly larger than the thickness of rotor 44, so that the fingers 115 straddle the rotor. With this arrangement, the rotor 44 passes between fingers 115, and the fingers 115 pick the rounds of ammunition out of the rotor as the rotor passes adjacent the clip 22. 
     As illustrated in FIG. 6, rotor 44 has been rotated one complete revolution after having been filled with ammunition. The inner circular supply of ammunition will have been moved by the rotor in a counterclockwise direction, and the spiral divider 78 will have caused those rounds of ammunition to have moved into an intermediate portion of the spiral path of the drum. In the meantime, intermediate and outer layers of ammunition will have also progressed, with the outer line of ammunition having been picked from the drum by the fingers protruding inwardly of the drum from the clip magazine 22, so that the outer ammunition will have passed upwardly through the clip 22. In the meantime, the last round follower will have progressed along with the other rounds of ammunition from its innermost position into an intermediate portion of the spiral path. 
     It should be noted that after two revolutions of the rotor 44, all of the rounds of ammunition will have been picked from the outer semicircular recesses 76 of the dividers 52, and these recesses will remain empty during the remaining revolutions of the rotor 44. 
     FIG. 7 illustrates the rotor 44 after it has been rotated through three complete revolutions. It will be noted that the innermost and intermediate layers of ammunition will have progressed through the spiral drum magazine and its clip magazine, and only the outer portion of the spiral path still has ammunition remaining therein. Also, the last round follower 85 is about to move from the intermediate portion of the spiral path to the outer portion thereof. 
     As illustrated in FIG. 8, after four complete revolutions of the rotor 44, the last round follower 85 finally makes contact with the last round of ammunition, with its protruding end portion pushing against the last round 84A. The fingers 115 pick the protruding portion of the last round follower out of its slot between the dividers of the rotor and cause the protruding portion to progress upwardly through the magazine clip 22. 
     As illustrated in FIG. 8, the last round follower has a notch 118 formed thereon, and when the last round follower 85 has been fully distended into the clip magazine 22, the notch 118 engages guide 112, thereby terminating any further movement of the last round follower 85 upwardly through the clip magazine 22, so that the last round follower will not protrude too far into the clip magazine. Further, engagement between the last round follower and the guide 112 tends to terminate the rotary movement of rotor 44. In the event that notch 118 should not properly register with guide 112, last round follower 85 simply wedges in the clip magazine 22 and therefore prevents further rotary movement of rotor 44. 
     While this invention has been described in detail with particular reference to a preferred embodiment thereof, it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinbefore and defined in the appended claims.