AU752291B2

AU752291B2 - Ammunition feed for beltless fed ammunition

Info

Publication number: AU752291B2
Application number: AU13588/00A
Authority: AU
Inventors: Rudi Beckmann
Original assignee: Heckler und Koch GmbH
Current assignee: Heckler und Koch GmbH
Priority date: 1999-01-28
Filing date: 2000-01-27
Publication date: 2002-09-12
Anticipated expiration: 2020-01-27
Also published as: ATE323273T1; EP1024338A2; PT1024338E; EP1024338B1; DE50012545D1; EP1024338A3; DE19903346C1; AU1358800A

Abstract

A beltless ammunition feed for a self loading weapon has the ammunition loaded into an endless loop feed which follows a meandering track through the magazine. The rounds are transferred to the weapon by a loop with guide wheels (28,30) at each end. One of the guide wheels (30) is driven and the other is fitted with a one way clutch to prevent the feed pulling back after each discharge. This reduces the stress peaks for the drive and provides a smoother feed rate, with the main loop moving at a near steady rate.

Description

-1- 1. 1 P/00/0011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

C

C. Name of Applicant: Actual Inventor: Address for service in Australia: Invention Title: HECKLER KOCH GMBH Rudi BECKMANN CARTER SMITH BEADLE 2 Railway Parade Camberwell Victoria 3124 Australia AMMUNITION FEED

AMMUNITION

FOR BELTLESS FED The following statement is a full description of this invention, including the best method of performing it known to us I

I

AMMUNITION FEED FOR BELTLESS FED AMMUNITION The invention concerns an ammunition feed device to feed beltless fed ammunition into a self-loading weapon, in particular, with an endlessly guided ammunition feed chain to feed ammunition into the weapon, at least two deflection units to guide the ammunition feed chain, and a drive for intermittent driving of one of the deflection units, in order to intermittently feed ammunition to the weapon in the ammunition feed direction.

~This type of ammunition feed device is known from the generic US-4 573 395. This document also shows an ammunition magazine with an ammunition guide chain connected to the ammunition feed device. A short loop of the ammunition guide chain is decoupled from the movement of the rest of the ammunition guide chain, two bends of this loop being guided to move parallel to each other via a rocker force-coupled in the feed direction of the .•ammunition guide chain.

Ammunition magazines with a transfer device to transfer the ammunition to an ammunition feed device are also known from DE-36 44 513 C2 and EP-078 49? B 1. Further details concerning this ammunition feed device, however, cannot be gathered from these documents.

A shortcoming of the known ammunition feed devices is as follows. In the case of self-loading weapons as drive, the ammunition introduction movement is usually intermittent, short, rapid accelerations and a subsequent stop occur. The weapon ordinarily serves as drive for both the ammunition feed chain and for a transfer device operating between an ammunition magazine and the ammunition feed device and for the ammunition guide chain in the ammunition magazine. The entire insert mass of these units must therefore be accelerated during each shot and then braked again. The s ammunition feed chain of the ammunition feed device, however, is elastic, to a certain degree, and causes and back-and-forth rotational movement of the undriven deflection unit, the transfer device, as well as of the ammunition guide chain in the ammunition magazine because of the corresponding restoring forces. As already mentioned, the latter units have high insert mass, so that the acceleration and braking forces are correspondingly high during the ooooo corresponding back-and-forth movement.

If the undriven deflection unit moves opposite the ammunition feed direction, the drive of the driven deflection unit must apply a large force 'i (energy) during the next acceleration (the next shot), in order to first brake this movement occurring in the opposite direction and then accelerate it in the correct direction. The drive of the deflection unit therefore had to be designed incomparably strong, so that it can apply this acceleration. The ammunition feed chain is also loaded unnecessarily severely and must therefore be designed correspondingly strong.

The underlying task of the invention is to further develop an ammunition feed device of the type mentioned at the outset, so that the acceleration forces being applied by the drive of the ammunition feed chain can be reduced with equivalent operating speeds of the ammunition feed chain.

-2- The invention solves this task in an ammunition feed device of the type mentioned at the outset with the characterizing features of Claim 1.

Accordingly, the at least one undriven deflection unit is connected to a blocking device that blocks movement of the deflection unit opposite the ammunition feed direction. The blocking device therefore advantageously acts on the undriven deflection unit, so that a movement occurring in the opposite direction, in the most unfavorable case, need not first be braked, but can always be started from a standstill (or a movement in the ammunition feed direction) of the ammunition feed chain. The driven deflection unit therefore need only to accelerate the entire system in the feed direction and not first brake it, as just ooo.oi described. The drive of the driven deflection unit can therefore advantageously be dimensioned weaker. The loads acting on the ammunition feed chain are oooo also lower.

The term "ammunition feed chain" is only to be understood in the figurative sense, since the ammunition can be also guided, for example, by belts S" :or bands in the ammunition feed device in an endless loop. The term was merely chosen for easier readability of the present application, but is not to be understood as being restrictive.

The ammunition feed device can also be used to convey and store other objects. All devices that permit rotation in one direction of rotation and block it in the other are suitable as blocking device. A ratchet mechanism, etc. can thus be used.

Coupling of the undriven deflection unit to the blocking device can optionally occur via a feed shaft connected to the latter in shape-mated fashion, but this deflection unit can also directly have the blocking device, etc.

Movement of the deflection unit opposite the ammunition feed direction need not absolutely be blocked fully rigidly (for example, it can either be braked only sharply or only rigidly blocked after covering a short movement path opposite the ammunition feed direction). However, this movement is preferably rigidly blocked.

Additional preferred practical examples of the invention are described in 0 the dependent claims.

The blocking device that blocks the undriven deflection unit in any rotational position is advantageously a freewheel (Claim A ratchet mechanism, for example, blocks only after discrete, not arbitrarily small S" rotational angle changes, which correspond to the spacings between the individual ratchets. Rotation in both directions is possible within these rotational angle changes. This is no longer the case in a freewheel.

For adjustment of the ammunition feed chain, for example, after loading or unloading of the connected ammunition magazine with reference to the insertion mechanism of the self-loading weapon, the blocking device is preferably designed so that its blocking device, acting opposite the ammunition feed direction, is releasable (Claim 3).

The blocking device, as a particularly space-saving solution, preferably has an adjustment device to adjust the position of the ammunition feed chain, -4which can be necessary, for example, after loading of the connected ammunition magazine (Claim 4).

As a particularly simple to manufacture embodiment of the adjustment device, this advantageously has an externally activatable worm gear spindle and a gear rim coupled by external force to the undriven deflection unit, in which the worm gear spindle engages in the gear rim (Claim For an advantageously simple to manufacture embodiment of the release mechanism of the blocking device, this is rigidly connected to a ratchet wheel, in which a corresponding blocking cylinder engages, the blocking cylinder being arranged relative to the ratchet wheel, so that it blocks movement of the ratchet wheel when the ammunition feed chain is moved opposite the ammunition feed direction (Claim The blocking cylinder is preferably designed so that it also blocks the ratchet wheel during movement of the ammunition feed chain in the ammunition feed direction (Claim The blocking cylinder is also preferably designed as a cylindrical pin with a flat end surface that engages in the ratchet wheel, which can be made to engage releasably with the ratchet wheel via an eccentric device (Claim 8).

To advantageously prevent the aforementioned release mechanism from misaligning the ammunition feed chain during stopping of the release mechanism after setting of the position of the ammunition feed chain, a device is provided that brings the blocking cylinder into a defined engagement position in the ratchet wheel (Claim This device is preferably a spring-loaded cylindrical pin with a hemispherical end surface that engages in the ratchet wheel (Claim The undriven deflection unit is preferably connected to a transfer device that is designed for exchange of ammunition or spent ammunition with an ammunition magazine connected to the ammunition feed device, in which the movements of an ammunition guide chain, also provided in the ammunition magazine, and the movements of the ammunition feed chain are coupled (Claim 11). Thanks to the invention, back-and-forth movements are advantageously suppressed, even with such coupled movement of several ammunition feed S1 0 devices.

o: :i The ammunition feed device preferably has at least one chain tightener to tighten the ammunition guide chain and/or the ammunition feed chain with a stipulated chain tension, in which the chain tightener carries out a clamping movement in the direction of tightening to increase the corresponding chain tension and a clamping movement opposite the direction of clamping to reduce S. the chain tension, and the chain tightener has a device to influence the spring constant of the chain tightener as a function of the direction of tightening and the speed of the tightening movement (Claim 12). With this expedient, the wide variety of movement situations of the ammunition guide chain (heatrelated material expansions, acceleration or braking, etc.), which influence the clamping movement of the chain tightener, can advantageously be allowed for, so that slack, in particular, in the ammunition guide chain, can be avoided as much as possible.

The invention, as well as additional advantages and features of the invention, are further explained below with reference to a preferred practical example relative to the accompanying drawing. In the drawing: FIG. 1 shows a schematic side view of a section of an ammunition magazine.

FIG. 2 shows a side view of the ammunition magazine depicted in FIG.

1; :o FIG. 3 shows another side view through the ammunition magazine *...depicted in FIG. 1; FIG. 3a shows an enlarged section of FIG. 3; FIG. 4 shows a view of a freewheel with releasable barrier coupled to a deflection roll.

An ammunition magazine 2 is depicted in FIG. 1, in which an endlessly guided ammunition guide chain 6 conveys cartridges 4 in feed direction A. The ammunition guide chain 6 consists of two high-tensile strength, parallel guided transport chains, whose spacing relative to each other essentially corresponds to the length of the cartridge. The two parallel transport chains are connected to each other at constant spacing via crosspieces 8. The spacing of crosspieces 8 from each other is essentially equal to the cartridge diameter plus the diameter of a crosspiece 8 and a certain play for free movement of the guided cartridges 4. The endless ammunition guide chain 6 so formed is guided in several loops over deflection rolls 10, 12, 14 and 16 through the section of ammunition magazine 2 depicted in FIG. 1.

-7- The cartridges 4 within ammunition magazine 2 are guided in guide tracks 18 with limited free mobility, which are provided, for example, with sliding/roller rails made of low-wear plastic. The rigid, thin crosspieces 8 each separate two consecutive cartridges or their casings from each other and s convey them through the guide track 18 into ammunition magazine 2.

The crosspieces 8 can have a profile adapted to the cartridge shape, with which jamming of the cartridges 4 is avoided as much as possible. The -crosspieces 8 can also be mounted to rotate axially on the two chains of the ammunition guide chain 6, in order to facilitate rolling of the cartridges 4 within 0o the guide track 18 and thus also on the crosspieces 8.

In a center loop of guide track 18 (in the practical example depicted in "'FIG. 1 in the left center of ammunition magazine 2) the cartridges are transferred via a feed gear 20 and transfer gears 22 and 24 to an ammunition feed device 25. The ammunition feed device 25 has an ammunition feed chain 26 that is guided in an endless loop around a first 28 and a second 30 deflection 0o6• roll and forms several consecutive shell-like receiving containers 32. The receiving containers 32 are dimensioned so that they can each accept one cartridge 4. The ammunition feed chain 26 is again guided within a guide track 34. In the vicinity of the second deflection roll 30 a self-loading weapon can be provided, which accepts the cartridges fed by the ammunition feed chain 26, fires them and transfers the empty cartridge casings to the ammunition feed chain 26.

During one shooting sequence, cartridges 4 are thus transported by the ammunition guide chain 6 in feed direction A to the feed gear 20, necessarily transferred there via the transfer gear 22 to a corresponding receiving container 32 of the ammunition feed chain 26, whereas, at the same time, a cartridge lying farther forward (viewed in feed direction B) is loaded at the second deflection roll 30 by a weapon (not shown). The cartridge casing remaining from the previous shot is simultaneously transferred with loading of the new cartridge to the ammunition feed chain 26, whereas an additional empty cartridge casing is transferred by the second deflection roll 28 via the transfer gear 24 necessarily to feed gear 20 and thus to the ammunition guide chain 6.

The empty cartridge casings are also transported further via the deflection rolls 16 and 12.

The feed gear 20 and the two transfer gears 22 and 24 are connected in shape-mated fashion to the first deflection roll 28, so that the loading force of the weapon engaging via the second deflection roll 30 drives the ammunition S" feed chain 26, the first deflection roll 28, the two transfer gears 22 and 24, the feed gear 20 and also the ammunition guide chain 6.

By variation of the relative position of the first deflection roll 28 and the two transfer gears 22 and 24 to the feed gear 20, a large connection angle range of the ammunition feed chain 26 to the ammunition magazine 2 can be covered.

The first and second deflection rolls 14 and 16 forming a loop of the ammunition guide chain 6 are arranged to move in the feed direction A of the ammunition guide chain 6. FIG. 2 is referred to for this purpose.

FIG. 2 shows a schematic side view of the ammunition magazine 2 s depicted in FIG. 1. A first 36 and a second 38 connecting rail are provided in the depicted side of the ammunition magazine 2 to accept a first 40 and a second 42 slide. The first slide 40 is guided to move over rollers 44 and 46 in the first connecting rail 36 and carries the axis of the first deflection roll 14.

The second slide 42 is likewise guided to move over rollers 48 and in the second connecting rail 38 and carries the axis of the second deflection oooe@ roll 16. The end ofa first rod 52 is mounted to pivot on the first slide whose other end is connected to pivot with the first end of a rocker 54. The end of a second rod 56 is likewise mounted to pivot on the second slide 42, whereas the second end of the second rod 56 is connected to pivot with the second end of rocker 54. The rocker 54, in turn, is guided to move over a .oo.

pivot axis 58 in an additional connecting rail 60. To this extent, the ammunition guide chain 6 can be either tightened or loosened via the movable rocker 54, the two rods 52 and 56, the two slides 40 and 42 and the two deflection rolls 14 and 16.

As described above, the weapon can drive the feed gear 20 and, indeed, intermittently in the firing cycle of the cartridges. Within each drive pulse, the ammunition guide chain 6 is initially accelerated strongly and then braked again. Strong tensile forces occur during acceleration in the ammunition guide chain, since its inert mass is very high, owing to the numerous cartridges present. This tensile force during the acceleration phase is compensated by rocker 54, the first deflection roll 14 being moved rightward during acceleration in the practical example depicted in FIG. 1, so that only the section of the ammunition guide chain 6 situated between feed gear 20 and the first deflection roll 14 need be accelerated. A slack in the ammunition guide chain 6 is simultaneously formed between the feed gear 20 and the second deflection I "roll 16, which, however, is compensated by the rocker 54. If the first deflection roll 14 moves rightward in FIG. 1, the moving slide 40 moves t0 leftward in FIG. 2, the slide 42 is necessarily moved rightward in FIG. 2 by rocker 54, which again means movement of the second deflection roll 16 in FIG. 1 to the left. With a fixed rocker 54, the slack between feed gear 20 and the second deflection roll 16 developing by shortening of the loop depicted in FIG. 1 between feed gear 20 and the first deflection roll 14 would be precisely eliminated.

S- A toothed segment 62, into which a gear 64 engages, is rigidly connected to rocker 54. The gear 64 activates a potentiometer 68 via a transfer linkage 66. The pivot position of rocker 54 can therefore be measured with the device consisting of toothed segment 62, gear 64, transfer linkage 66 and potentiometer 68. The potentiometer 68 is connected as a bridge branch of a Wheatstone Bridge (not shown), whose other bridge branch consists of two series-connected resistors. The output of the Wheatstone Bridge tapped between the two resistors and the center tap of the potentiometer 68 delivers a -11current, with appropriate dimensioningofthe resistors and potentiometer, which equals zero in the center position of rocker 54 and is otherwise positive or negative, depending on the position of rocker 54. This output signal is fed to a drive (not shown) connected in shape-mated fashion to the deflection roll 10. The drive is controlled so that it attempts to pivot rocker 54 back into the rest or zero position.

Instead of this electrically designed control, an appropriately designed S. hydraulic control can also be provided.

With the rocker design and the deflection roll 10 driven independently S1o of it, the intermittent motion of the ammunition feed chain 26 and feed gear produced by the weapon is converted to a uniform movement of the ~ammunition guide chain 6.

Figures 3 and 3a show a cross section through the ammunition C Co magazine 2. The section is through a center surface along the connecting rail 60 of rocker 54. In the depicted practical example the rocker 54 is provided on .both side surfaces of the ammunition magazine 2. The corresponding pivot axis 58 of rocker 54 is mounted in a transverse bridge 70 that connects the two rockers 54 together. The transverse bridge 70 is therefore guided to move within connecting rail 60 on both sides.

A chain tension spring 72 provided on both sides acts between the rigid housing of the ammunition magazine 2 and the moveable cross bridge 70. For this purpose, the chain tension spring 72 is secured in a spring guide cylinder 74 rigidly connected to the housing of the ammunition magazine 2, whereas its -12free moving end is forced against cross bridge 70 via a spring guide rod 76.

Overall, the chain tension spring 72 forces the entire rocker 54 rightward in the practical example shown in FIG. 2, so that the two deflection rolls 14 and 16 shown in FIG. 1 are also forced rightward. Because of this, the ammunition guide chain 6 is prestressed with a certain stipulated chain tension. The chain tension is obtained from the spring constant of the chain tension spring 72 and its engagement position. For ordinary coil springs, the linear Hooke's Law applies over broad ranges of engagement position.

If the ammunition guide chain 6 is accelerated via the feed gear 20, such t 0 strong forces briefly occur in the ammunition guide chain 6 that the tightening s~ees.: force of the chain tension spring 72 is overcome. The result is that the entire rocker 54 is moved leftward in the practical example depicted in FIG. 2, so that too.

overall a slack develops in the ammunition guide chain 6. In the most "unfavorable case, the force occurring from the jerky acceleration can force the chain tension spring 72 up to the stop. The still present motion impulse is taken up at the stop in the entire material of the ammunition magazine 2. This can, at worst, lead to undesired material cracks or breaks.

The expedient of increasing the spring constant of the chain tension spring 72 so strongly that such a case can essentially be ruled out does not lead to the objective here. With high spring constants, the tightening force exerted by the chain tension spring 72 is already so strong after its engagement over a short zone that the ammunition guide chain 6 is needlessly tightened, so that guide problems and material fatigue can occur. Such a short-zone engagement -13of the chain tension spring 72, however, can already be caused, for example, by heat-related material expansions, since different materials are used for the housing of the ammunition magazine 2 (aluminum, carbon fiber composite, etc.) and the ammunition guide chain 6 (steel, etc.). To this extent, the spring constant of the chain tension spring 72 should be chosen so that even during sharp temperature changes and the accompanying engagement and disengagement movements, the tightening force exerted by the chain tension spring 72 on the ammunition guide chain 6 remains in the acceptable range.

o* So• In order to nevertheless prevent stopping in chain tension spring 72 so 9. oo o go0 dimensioned, a hydraulic cylinder 78 is provided on both sides of the ammunition magazine 2, whose cylinder is rigidly connected to the spring guide 0.0.

cylinder 74. A piston 80 is guided parallel to the direction of action of the see* chain tension spring 72 in hydraulic cylinder 78. A piston rod 82 of piston 80 is 9**S*4 connected to the cross bridge 70 by external force via a T-groove 84. A ball ooo* return valve 86 is also provided in piston 80 that closes during engagement of piston 80 in the cylinder, in which the closure movement is essentially caused by a spring device. During disengagement of the piston 80, the ball return valve 86 opens because of the hydraulic fluid flowing through a ventilation channel of the ball return valve 86 in hydraulic cylinder 78.

The hydraulic cylinder 78 is dimensioned so that a rapid engagement movement of its piston 80 counteracts an essentially infinite resistance. During such a rapid engagement movement, the hydraulic cylinder 78 therefore blocks movement of cross bridge 70 via piston rod 82 leftward in the practical -14example depicted in FIG. 3. A rapid movement of cross bridge 70 leftward occurs, as described above, in a case in which the feed gear 20 accelerates the ammunition guide chain 6. The hydraulic cylinder 78 therefore ultimately causes an increase in spring constant of the chain tension spring 72 to an almost infinite value. This corresponds to the case in which the cross bridge 70 and the rocker 54 are rigidly connected to the housing of the ammunition magazine 2. The total acceleration forces are therefore transformed only to a pivoting movement of rocker 54 and, with appropriate delay, are compensated by the two drives of deflection rolls 10 and 12. In other words, the clamping movement opposite the direction of tightening of the ammunition guide chain 6 is essentially blocked: No slack can therefore develop in the ammunition guide chain 6.

S•In clamping movements that occur very slowly in time, for example, as caused by material heat expansion, the piston 80 can engage without great 15 resistance in the hydraulic cylinder 78, since the gap between piston 80 and the cylinder is correspondingly dimensioned. For such slow speeds, the hydraulic cylinder 78 therefore does not pose an additional resistance, so that the spring constant of the chain tension spring 72 essentially assumes its normal value for adjustment of the stipulated chain tension.

Should slack develop in the course of acceleration of ammunition guide chain 6, should the chain tension spring 72 be engaged via its position in the normally stressed chain, the restoring force acting from the chain tension spring 72 from the engaged position can fully act on cross bridge 70, with the normal spring constant. The piston 80 experiences no significant resistance during disengagement from the cylinder, since the ball return valve 86 opens during disengagement. In other words, the spring constant during a clamping movement of the chain tension spring 72 is essentially independent of speed and assumes the normal value for adjustment of the stipulated chain tension. This naturally also applies to slow expansion movements, for example, because of material heat expansion of the ammunition guide chain 6, since the resistance of piston 80 during disengagement is essentially independent of speed.

FIG. 2 also shows a chain adjuster 90, which acts on the feed gear or the first deflection roll 28. The chain adjuster 90 has a pivotable worm gear pair 92 that can be driven by a driveshaft stump 94. On the axis of the feed gear 20 and the first deflection roll, a gear rim 96 is rigidly mounted on the 'i outside on the housing, into which the pivoted worm gear pair 92 can engage.

The position of the ammunition guide chain 6 can therefore be moved by 15 rotating the worm gear pair 92, which, in the pivoted state, rotates the gear rim 96 and thus the feed gear 20 and the first deflection roll 28.

The ammunition supply in ammunition magazine 2 can be filled up in the shortest time using appropriate ground equipment, for example, a beltless supply vessel, which operates according to the same functional principle, whereas the empty cartridge casings or misfires can be removed at the same time. After the filling process, the ammunition guide chain 6 is brought to the appropriate position via the driveshaft stump 94, so that it can cooperate optimally with the self-loading weapon.

-16- FIG. 4 shows a view of a freewheel with a releasable barrier for the first deflection roll 28. The ammunition feed chain 26 of the ammunition feed device 25 represents an elastic mass during its motion around the two deflection rolls 28 and 30. When the deflection roll 30 is driven by the weapon with interruptions, briefly accelerated and braked, the ammunition feed chain 26 is stretched on the cartridge feed side, while it is compressed on the cartridgecasing withdrawal side. The first deflection roll 28 is accordingly *:edriven in delayed fashion by the second deflection roll 30 via the ammunition feed chain 26.

io The second deflection roll 30 stands still, at times, between shots, S: whereas the ammunition feed chain 26, because of its inert mass and the :'restoring forces, still cannot immediately assume its rest position. The compressed or stretched chain sections cause restoring forces in the ammunition feed chain 26 that bring the first deflection roll 28 to back-and- 15 forth rotation.

If during subsequent acceleration of the second deflection roll 30, for example, on the next shot, the ammunition feed chain 26 accelerates on the cartridge feed side in the feed direction B, it can happen in the most unfavorable case that the deflection roll 28 carries out a rotational movement in precisely the opposite direction. Since the deflection roll 28 is connected by external force to the feed gear 20 via transfer gears 24 and thus to the entire ammunition guide chain 6 in the ammunition magazine 2, during this back-andforth rotational movement of deflection roll 28, a large inert mass is moved.

-17- This inert mass, however, must now be overcome by the drive of the deflection roll 30, so that the first deflection roll 28 is first braked and then brought to rotational movement in the direction of feed direction B. Overall, the drive of deflection roll 30, in this case, must accelerate a very large mass, so that this drive has to be dimensioned incomparably strongly and the ammunition feed chain 26 has to be designed to be incomparably strongly loadable.

To avoid this excess dimensioning, the first deflection roll 28 is rigidly connected to a freewheel 119 (see also FIG. which blocks rotational movement of the first deflection roll 28 against feed direction B. Because of this freewheel 119, no acceleration of the deflection roll 28 or the units S connected to it can occur opposite feed direction B, so that the drive of the second deflection roll 30 must always accelerate only the entire inert mass of the ammunition feed chain 26, but need not brake it first.

Since the drive always brings the second deflection roll 30 to a 15 stipulated position, which is stipulated, for example, by the discharge mechanism of a self-loading weapon, by stretching of the ammunition feed chain 26 on the cartridge feed track and the accompanying restoring force, the first deflection roll 28 is then rotated so far in feed direction B that the ammunition feed chain 26 is slightly compressed on the cartridge feed side.

Subsequent acceleration of the second deflection roll 30 overall still has to apply less force, since the ammunition feed chain 26, prestressed positively for this acceleration, can furnish part of its chain tension to the acceleration. The chain part on the cartridge casing withdrawal track is simultaneously expanded -18to the extent that the part on the cartridge feed side is compressed. For this reason, restoring forces caused by the ammunition feed chain 26 are established on both tracks so that the acceleration is supported by the second deflection roll The freewheel 119 is not further explained below, since its function and design are adequately known from the prior art. Moreover, any other appropriate type of blocking device can be used for freewheel 119 that permits rotation of the first deflection roll 28 in one direction and essentially blocks it in the other direction (preferably rigidly).

If freewheel 119 is used as blocking device, its blocking action is essentially not releasable in one direction of rotation without difficulty.

Nevertheless, to permit loosening of this blocking effect in freewheel 119, the freewheel 119 is connected to an additional releasable barrier that is further explained below with reference to FIG. 4.

S" 15 FIG. 4 shows such a releasable barrier, which is connected by outside a.

force to freewheel 119. In particular, the freewheel sits in a ratchet wheel 102 and is rigidly connected to the first deflection roll 28. A housing 115 of this releasable barrier has a blocking cylinder 108 engaged with the ratchet of ratchet wheel 102. The blocking cylinder 108 has a flat end surface that abuts the steep flanks of the ratchet of ratchet wheel 102 when the blocking cylinder 108 is disengaged by an eccentric shaft 112. Clockwise rotation of the ratchet wheel 102 in the practical example depicted in FIG. 4 is thus blocked. Rotation of the ratchet wheel 102 counterclockwise is also blocked by the disengaged -19blocking cylinder 108, since its outer surface precisely abuts the flat flank of a ratchet. The releasable barrier therefore blocks movement of the ratchet wheel 102 when the blocking cylinder 108 is disengaged, when the ammunition feed chain 26 is moved both in and against the feed direction B. Axis 120 is therefore only rotatable in the direction stipulated by freewheel 119.

The blocking cylinder 108 is guided in the housing 115, from which the blocking cylinder 108 can be disengaged essentially tangentially in the direction of ratchet wheel 102. The disengagement movement is caused by the eccentric shaft 112, which can be activated by a rotating rod (not shown). A small recess is provided in the eccentric shaft 112, into which a blocking pin 116 can engage radially. This blocking pin 116 is forced into this recess by the spring force of a spring 118. The eccentric shaft 112 is then aligned with the recess, so that the blocking pin 116 engages in the recess when the blocking cylinder 108 is fully disengaged. This prevents the eccentric shaft 112 from being unintentionally o 15 rotated when the blocking cylinder 108 is disengaged and the ratchet wheel 102 is blocked.

The end surface of the blocking pin 116 acting on eccentric shaft 112 is designed so that, with application of a corresponding torque on the eccentric shaft 112, the recess is freed of the locking pin 116, so that the eccentric shaft 112 can be rotated and the blocking cylinder 108 can be engaged in housing 115. The ratchets of ratchet wheel 102 can then engage the blocking cylinder 108 in housing 115 during movement of the ratchet wheel 102 clockwise, so that the blocking effect on the ratchet wheel 102 is eliminated in this direction of rotation.

With the blocking effect released on ratchet wheel 102, the first deflection roll 28 can therefore also be rotated against the feed direction B.

The freewheel 119 blocks such motion, but since it is rigidly connected to ratchet wheel 102 and this can now be rotated opposite feed direction B, the blocking effect of freewheel 119 is therefore eliminated. In this state, the ammunition magazine 2 can be loaded or unloaded, whereupon the position of the ammunition feed chain 26 is established.

If the ammunition feed chain 26, after the loading or unloading process, is brought back precisely into its position relative to the drive of the second deflection roll 30 (for example, the self-loading weapon), in the most unfavorable case it can happen that the blocking cylinder 108 and a corresponding ratchet of ratchet wheel 102 are positioned relative to each .t'5 other, so that the eccentric shaft 112 cannot be rotated into the fully disengaged position of cylinder 108. Moreover, during a disengagement process of blocking cylinder 108 that overcomes this resistance, the ratchet wheel 102 is unintentionally rotated in a direction of rotation in which freewheel 119 blocks. As a result, however, the first deflection roll 28 is moved again because of this and the ammunition feed chain 26, aligned in position beforehand, is then misaligned again.

In order to prevent such misalignment during locking of the blocking cylinder 108, an additional cylinder 114 with a hemispherical end surface is provided, which also acts in housing 115 radially on the ratchets of ratchet wheel 102. The cylinder 114 is then moved by the spring force of a spring 118 radially in the direction of the ratchets. The hemispherical end surface now presses against the ratchets of ratchet wheel 102, so that the ratchet wheel 102 is always rotated in the clockwise direction of rotation, in which direction the *freewheel 119 does not block. Only movement of ratchet wheel 102 therefore occurs, but not movement of the first deflection roll 28. The spacing of the two cylinders 108 and 114 is then dimensioned so that, with a completely disengaged cylinder 114, if the hemispherical end surface is thus situated precisely between two ratchets, an optimal position of the blocking cylinder 108 is present with reference to the ratchets, so that the eccentric shaft 112 can fully disengage blocking cylinder 108.

S000

Claims

1. Ammunition feed device to feed beltless fed ammunition to an especially self-loading weapon, with: a) an endlessly guided ammunition feed chain to feed ammunition into the weapon, b) at least two deflection units to guide the ammunition feed chain' and c) a drive for intermittent driving of one of the deflection units in order to feed ammunition intermittently to the weapon in the ammunition feed direction characterized by the fact that d) the at least one undriven deflection unit lis connected to a blocking device that blocks movement of the deflection unit opposite the ammunition feed direction

2. Ammunition feed device according to Claim 1, characterized by the fact that the blocking device is a freewheel.

3. Ammunition feed device according to Claim 1 or 2, characterized by the fact that the blocking device is designed so that blocking acting opposite the ammunition feed direction is releasable.

4. Ammunition feed device according to one of the preceding Claims, characterized by the fact that the blocking device has an adjustment device to adjust the position of the ammunition feed chain. Ammunition feed device according to Claim 4, characterized by the fact that the adjustment device has an externally activatable worm gear spindle and a gear rim coupled by external force to the undriven deflection unit in which the worm gear spindle engages in the gear rim

6. Ammunition feed device according to one of the preceding Claims, characterized by the fact that the blocking device is rigidly connected to a ratchet wheel into which a corresponding blocking cylinder engages, the blocking cylinder being arranged relative to the ratchet wheel so that it blocks movement of the ratchet wheel when the ammunition feed chain is moved opposite the ammunition feed direction

7. Ammunition feed device according to Claim 6, characterized by the fact that the blocking cylinder is designed so that it also blocks the ratchet wheel: during movement of the ammunition feed chain in the ammunition feed direction

8. Ammunition feed device according to Claim 6 or 7, characterized by the fact that the blocking cylinder is designed as a cylindrical pin with a flat end surface that engages in the ratchet wheel which can be made to engage releasably with the ratchet wheel (102) via an eccentric device

9. Ammunition feed device according to one of the Claims 6 to 8, Scharacterized by the fact that a device is provided, which brings the blocking cylinder into a defined engagement position in the ratchet wheel Ammunition feed device according to Claim 9, characterized by the fact that the device is a spring-loaded cylindrical pin with a hemispherical end surface that engages in ratchet wheel a.

11. Ammunition feed device according to one of the preceding Claims, characterized by the fact that the intermittently driven deflection unit :is arranged in the vicinity of the weapon and driven by it.

12. Ammunition feed device according to one of the preceding Claims, characterized by the fact that the undriven deflection unit is connected to a transfer device, which is designed to exchange ammunition or spent ammunition with an ammunition magazine connected to the ammunition feed device in which the movements of an additional ammunition guide chain 'provided in the ammunition magazine and the ammunition feed chain are coupled.

13. Ammunition feed device according to Claim 12, characterized by: a) at least one chain tightener to tighten the ammunition guide chain and/or ammunition feed chain \with a stipulated chain tension, in which the chain tightener carries out a clamping movement in the direction of tightening to increase the corresponding chain tension and a clamping movement opposite the direction of tightening to reduce the chain tension, and b) the chain tightener has a device to influence the spring constant of the chain tightener as a function of the direction of clamping and the speed of the tightening movement.

14. Ammunition feed device substantially as hereinbefore described with reference to the accompanying drawings. DATED: 27 January 2000 CARTER SMITH BEADLE Patent Attorneys for the Applicant: HECKLER KOCH GMBH