US3410173A

US3410173A - Round control device

Info

Publication number: US3410173A
Application number: US682685A
Authority: US
Inventors: Bengt I Piskator
Original assignee: Army Usa
Current assignee: US Department of Army
Priority date: 1967-11-13
Filing date: 1967-11-13
Publication date: 1968-11-12
Anticipated expiration: 1985-11-12

Description

Nov. 12, 1968 B. l. PISKATOR ROUND CONTROL DEVICE 2 Sheets-Sheet 1 Filed Nov. 13, 1967 Nov. 12, 1968 l. PISKATOR ROUND CONTROL DEVI CE Filed Nov. 13, 1967 NVENTOR El E Ilq- I Piskuur BY` #LM/; M, X

ATTORNEY United States Patent O 3,410,173 ROUND CONTROL DEVICE Bengt I. Piskator, Chicopee Falls, Mass., assigner to the United States of America as represented by the Secretary of the Army Filed Nov. 13, 1967, Ser. No. 682,685 Claims. (Cl. 8933) ABSTRACT 0F THE DISCLOSURE A front and a rear pair of round control units are located in the receiver of a known automatic firearm so that the units in each pair are disposed 90 apart on opposite sides of a cartridge feed port and opposite a pair of round stops so as to cooperate therewith in holding a cartridge at a feeding position after passing through the feed port. Each of the round control units includes a compression-torsion spring with an extending arm and the round control units in each pair are arranged so that the arms are pressed apart by the cartridge when transferred to the feeding position and then spring back to cooperate with the round stops. The arms are swung rearwardly by the reciprocating barrel to prevent interference therewith when moving rearwardly to envelop the feed position cartridge.

The invention described herein may be manufactured, used, and licensed by or for the Government for governmental purposes without the payment to me of any royalty thereon.

The invention relates to machine guns of the type disclosed in U.S, Patents 3,318,191 to Reed, 3,320,855 to Reed etal, and 3,340,770 to Santos. Trouble has ben experienced with such machine guns because of jamming caused by the cartridge in the feeding position being misaligned with the barrel chamber as the barrel moves rearwardly to envelop it for discharge. This misalignment results from the cartridge being held by the feed pawl and apair of round stops solely at the area of the center of gravity. This support is not sufcient to completely secure the cartiridge against teetering caused by weapon vibration during tiring and therefore when the teetering is severe the front end of the cartirdge contacts the rear face of the rearwardly moving barrel rather than enter the chamber, causing the machine gun to jam.

It is, therefore the principal object of this invention to provide simple but effective means for securely holding the feeding position cartridge against teetering. Such means include four round control units arranged as a front and a rear pair simultanneously contactable by a cartridge, when moved to the feeding position, forwardly and rearwardly of its center of gravity. Each of the round control units include a compression-torsion spring with a tangentially extending arm portion. In each pair the arms extend angularly into the path of movement of the cartridge when moved to the feeding position so as to be pressed apart by the cartridge during movement thereto. The arms spring back to their normal positions for terminal contact with the cartridge when it reaches the feeding position.

A further advantage of this invention is that it eliminates any need to change the components of the machine gun when cartridges having cases of different material are used. A change in case material changes the center of gravity of the cartirdge, sometimes considerably, and where the feeding position cartridge is supported in the area of the center of gravity this requires that the feed pawl and round stop components be changed to conform to the new location thereof.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from 3,410,173 Patented Nov. l2, 1968 a description of a preferred embodiment as shown in the accompanying drawings in which:

FIG. 1 is an elevational view of the receiver and cam drum section of a machine gun of the aforementioned type:

FIG. 2 is an enlarged view taken along line 2 2 of FIG. 1 and shows a cartridge moved by the feed pawl towards the feeding position and the barrel located in its forward position;

FIG. 3 is a view similar to FIG. 2 but shows the cartridge in the feeding position;

FIG. 4 is a view similar to FIG. 3 but shows the barrel adjacent its rearward firing position;

FIG. 5 is an enlarged exploded view of one of the control units;

FIG. 6 is a view taken along line 6 6 of FIG. 3;

FIG. 7 is a View taken along line 7-7 of FIG. 2.

Shown in the figures is a machine gun 12 having a receiver 14 and a barrel 16 which reciprocates between a forward cartridge loading position and a rearward tiring position. A feeding mechanism 18 includes a feed pawl 20 arranged for vertical reciprocating to transfer a cartridge 22 downwardly to a feeding position in coaxial alignment with barrel 16, Receiver 14 includes a feed port 24 through which cartridge 22 is transferred into the receiver and an ejection port 26 located in the bottom of the receiver for ejection of the fired case of the cartridge therethrough.

'Cartridge 22 is stopped in the feeding position by a pair of round stops 40 which are fully described in U.S. Patent 3,340,770. Each of the round stops 40 is mounted in a longitudinal channel 42 provided therefor in receiver 14 and such channels are symmetrically disposed apart on opposite sides of ejection port 26. A tongue 43 on each of the round stops 40 provides the point of contact between the round stop and cartridge 22 and the tongues are arranged to contact the cartridge at approximately the center of gravity thereof, noted at C.G. in FIG. 6. Round stops 40 are each pivotally mounted between the front and rear ends thereof on a pin 44 so as to be displaceable by barrel 16 between a stopping position wherein tongues 43 are positioned to stop cartridge 22 at the feeding position and an open position wherein the tongues are clear of the barrel when adjacent its tiring position, to prevent interference therewith, and of ejection port 26 to permit passage of the fired case of the cartridge therethrough.

When cartridge 22 is located in its feeding position it is held steady therein ready for envelopment by barrel 16 by four round control units 46 which are mounted in receiver 14 as a front pair and a rear pair which are simultaneously contactable by the cartridge during transfer to the feeding position. The front pair contact cartridge 22 forwardly of the center of gravity thereof and the rear pair rearwardly of the center of gravity as is especially shown in FIG. 6. In each pair, round control units 46 therein are located 90 apart on opposite sides of feed port 24 so as to be symmetrical therewith and therefore are oppositely disposed relative to round stops 40, as shown in FIGS. 2-4, to cooperate therewith in holding cartridge 22 against teetering when in the feeding position.

Each of the round control units 46 includes a mount 51 having a shaft 52 with an essentially rectangular head 54 fixed to one end at right angles to its longitudinal axis. The opposite end of shaft 52 is bifurcated by a slot 56. Coiled around shaft 52 is a spring 58 which functions as a compression spring in one plane and as a torsion spring in another and which includes a plurality of spaced coils 60. The end of spring 58 that abuts inner face 62 of head 54 is terminated by an arm 64 which extends tangentially from the last one of the coils 60. The opposite end of spring 58 is terminated by locking section 66 that extends diametrically across the last one of the coils 69 so as to be receivable by slot 56 and thereby anchor that end of the spring to mount 51. Arm 64 is sufficiently rigid to withstand any linear pressure which may be applied by cartridge 22 to the end thereof, during operation of gun 12, without bending. The free end of arm 64 is terminated by a semicircular contact section 68 which extends rearwardly from the arm to provide arcuate contact of the arm with barrel 16 during reciprocation thereof.

Round control units 46 are mounted in receiver 14 within a pair of longitudinal channels 70 disposed on opposite sides of feed port 24 so as to be spaced 90 apart and symmetrical therewith. Extending similarly into each of the sides of channels 70 that face towards feed port 24 are two longitudinally spaced bores 72 the axes of which are normal to the extension of a radius respective to the longitudinal axis of barrel 16. Shafts 52 of the front pair of round control units 46 are received by the front ones of the bores 72 and the shafts of the rear pair are received by the rear ones of the bores. Bores 72 are each counter-bored at 74 to an annular ledge 76 for receiving spring 58.

Each of the round control units'46 is installed in receiver 14 by introducing the free end of its shaft 52 into one of the bores 72 and then pressing inwardly so that spring 58 thereon is partially compressed between ledge 76 and inner face 62 so as to be preloaded. Mount 51 is then locked in position by a pin 78 inserted through an accommodating aperture 80 in receiver 14 and cooperating holes 82 through shaft 52.

When round control units 46 are installed, arms 64 extend angularly into the path of movement of cartridge 22 when moved by feed pawl 20 to the feeding position with the arms of the front pair being directly opposite each other as are the arms of the rear pair. Thus, arms 64 are cammingly pressed apart by cartridge 22 when moved by feed pawl to the feeding position, the sidewise displacement of the rms causing an oblique compression of coils 60 in springs S8 as shown in FIG. 2. When cartrid-ge 22 reaches the feeding position, arms 64 are free to snap back to their normal positions in contact with the related inner faces 62 under the influence of the compressed coils 60, as shown in FIG. 3, whereby the cartridge is supported at the center of gravity by round stops and is held against teetering thereon by arms 64 of the front and rear pairs of the round control units. Arms 64 hold cartridge 22 securely through the rigidity of the arms and the preload introduced into springs S8 during installation which holds the arms resiliently against inner 'faces 62.

When barrel 16 moves rearwardly to envelop cartridge 22, rear face 84 of the barrel camming contacts arms 64 of the front pair of round control units 46, when the projectile of the cartridge is located within the barrel, and is thereby secured against jamming, this contact swings the arms 64 upwardly, winding the respective springs 58, into channels 70 and out of interference with barrel 16. During continued rearward travel of barrel 16 arms 64 of the rear pair of round control units 46 are cammingly contacted by rear face 84 and are similarly cammed out of interference with the barrel.

When the chambered cartridge 22 is fired and barrel 16 moves forwardly arms 64 are released after rear face 84 passes thereby and are swung to their normal positions, under the influence of the torque introduced in springs 58 when wound, ready to aid in supporting the next incoming cartridge.

The present invention has been described in detail above for the purpose of illustration only and is not intended to be limited by this description or otherwise except as defined by the scope of the appended claims.

I claim:

'1. In a machine -gun having a receiver, a barrel disposed for longitudinal reciprocation between a forward cartridge loading position and a rearward ring position and a feeding mechanism including a vertically reciprocating feed pawl for transferring a cartridge through a feed port in the receiver downwardly to a feeding position therein in coaxial alignment Iwith the barrel for envelopment thereby, the combination including a pair of round stops arranged to stop downward transfer of the cartridges by the feed pawl at the feeding position, a

plurality of pairs of round control units, one pair of said round control units being mounted in the receiver on opposite `sides of the feed port and forwardly of the center of gravity of the cartridge when in the feeding position, one pair of said round control units being mounted in the receiver on opposite sides of the feed port and rearwardly of the center of gravity of the feeding position cartridge, each said round control units including a spring designed to function as a torsion spring in one plane and as a compression spring in another, and a mount for mounting said spring in the receiver so as to be compressed by the cartridge during transfer to the feeding position and then snap back vto normal position to cooperate with the mound stops in holding the cartridge against teetering when in the feed position and so as to be wound by the barrel out of interference therewith during envelopment of the cartridge.

2. The invention as defined in claim 1 wherein said spring includes an arm arranged when in a normal position for terminal contact With the cartridge opposite said round stops to cooperate therewith in holding the cartridge against teetering in the feeding position and for angular extension into the path of movement of the cartridge to the feeding position so as to be deflected out of interference therewith by camming contact of the cartridge.

3. The invention as defined in claim 2 wherein said spring is mounted by said mount in the receiver so that said arm is swung rearwardly to wind said spring by Contact of the barrel with said arm during travel to the rearward firing position, and including a channel in the receiver for receiving said arm when swung rearwardly by the barrel.

4. The invention as defined in claim 3 wherein said spring includes a plurality of coils sufficiently spaced to permit oblique compression thereof by said arm when deflected by the cartridge and said arm extends tan- `gentially `from one end of said spring, and a locking section formed at the opposite end of said spring so as to be received by a slot in said mount for anchoring the opposite end of said spring thereto.

5. The invention as defined in claim 4 wherein said mount includes a shaft bifurcated at one end by said slot and arranged to be inserted through said coils, a head .-xed to the opposite end of said shaft, and an inner face of said head resiliently contacted by said arm to hold said arm in its normal position against deflection by the cartridge after reaching its feeding position.

References Cited UNITED STATES PATENTS 3,311,021 3/1967 Reed 89-33 BENJAMIN A. BORCHELT, Primary Examiner.

S. C. BENTLEY, Assistant Examiner.