US3314183A

US3314183A - Firearm

Info

Publication number: US3314183A
Application number: US415307A
Authority: US
Inventors: Warren A Center
Original assignee: HARRINGTON AND RICHARDSON Inc
Current assignee: HARRINGTON AND RICHARDSON Inc
Priority date: 1964-12-02
Filing date: 1964-12-02
Publication date: 1967-04-18
Anticipated expiration: 1984-04-18

Description

April 18, 1967 w. A. CENTER FIHEABM 2 Sheets-Sheet l Filed Deo. 2, 196'4 April 18, 1967 w. A. CENTER 3,314,183

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7 W9 A WJNN .fl./ m N/ 7 y 4N ww w @www QN N+ United States Patent O 3,314,183 FIREARM Warren A. Center, Westminster, Mass., assignor to Harrington & Richardson, Inc., Worcester, Mass., a corporation of Massachusetts Filed Dec. 2, 1964, Ser. No. 415,307 3 Claims. (Cl. 42-69) This invention relates principally to semi-automatic firearms of the type including a combined gas-operated and blow-back action wherein there is provided gas-operated piston means for unlocking the bolt and initiating the rearward travel thereof after the cartridge is fired, whereupon the blow-back continues the action to move the bolt to its rearwardmost position for ejecting the spent cartridge case and including means for returning the bolt once more to locked breech-closed position with a new cartridge in place, ready for the next shot. The firing mechanism may include a disconnector for repositioning a part of the sear operating mechanism to allow the sear and trigger to be moved to cocked condition.

Objects of the invention include the provision of a firearm as above described in which the gas-operated portion of the mechanism deviates from the White principle by having the force of the gas directed to the forward portion of the piston, causing the same to be retracted to a venting location and to impress its force upon the forward end of an action bar which is connected to the bolt for unlocking it, to the end that the gas-operated portion of the device is made simpler and less expensive as well as more positive in its action; and the provision of a gasoperated devi-ce of the class described including very simple and effective means for interdicting the action of the gas piston, so that the firearm becomes a manually operated device for single shots, throwing grenades, etc.

A still further object of the invention resides in the provision of a new and improved firing mechanism for firearms including a spring-pressed pivoted hammer and a new and improved sear, this sear having a pivoting action about an axis which is closer to the hammer axis than is the interconnection between the Sear nose and the hammer, whereby pressure of the hammer on the sear is in a direction to positively prevent accidental tiring by the sear nose slipping off the hammer, and as a matter of fact the greater the pressure in this direction, the greater is the force by which the sear is maintained in position.

A further object of the invention resides in a new and improved safety device which acts directly on the trigger and has a portion in the trigger guard by which it is easily moved to inactive condition of the safety, but at the same time the safety can be moved back to safety condition upon a pull in a rearward direction, i.e., in the same direction as the trigger pull, the safety being very closely associated therewith for quick andeasy operation thereof.

A still further object of the invention resides in the provision of a new and improved receiver plug including means so that the same is always located in exactly the same position regardless of how often it may be removed and reapplied to the receiver.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings in which:

FIG. 1 is a View of the firearm in elevation with the fore end removed;

FIG. 2 is an enlarged view with parts removed and in section showing the action as it appears in cocked condition ready to fire;

FIG. 3 is a longitudinal sectional view showing the gas operating mechanism; Y

FIG. 4 is a section on line 4 4 of FIG. 3;

ice

FIG. 5 is a section on line 5 5 of FIG. 2 through the breech plug;

FIG. 6 is a bottom plan view of the rear end of the bolt;

FIG. 7 is a top plan view of the rear end of the action box, and

FIG. 8 is a sectional view showing a modified bolt.

In illustrating the invention it must be understood that any kind of stock can be utilized and therefore the stock has not been shown but only the parts of the firearm which are pertinent to the invention. In this case there is a barrel 10 to which the receiver 12 is attached by any desired or convenient means. At the under side of the barrel adjacent the muzzle there is a vent 14 through which the explosion gases proceed to enter the gas cylinder which is indicated at 16. This gas cylinder is secured to the `barrel by any desired means such as being welded thereto or the like. In the gas cylinder there is a piston 18 which has a head portion 20 containing a chamber receiving the expanding gas. This chamber leads to a smaller chamber 22 and the action is that the gas entering the larger chamber first is in effect slowed to reduce the otherwise sharp flow of the piston 18 in its rearward motion contacting the forward end 24 of the action bar 26. This causes the action bar to be retracted smoothly against the action of the action bar spring 28. The action bar spring returns the action bar piston and bolt to breech-closed position of the firearm as will be described more fully hereinafter.

There is a gas plug generally indicated at 30 which can be turned by its head or by a screwdriver or the like and this plug is threaded into the forward end portion of the gas cylinder as at 32.` It is generally cylindrical and hollow in form and is provided with a radial vent 34 which is normally aligned with vent 14 so that the gas enters the gas plug and impinges upon the head of the cylinder as described. However merely by lturning the gas plug a slight amount the vent 14 will be cut off and when this vent is cut off the automatic action of the firearm is completely inhibited.

The bolt of the firearm is indicated at 36 and when it is in forward breech closed condition with the firearm ready to fire, it is locked in this position with the rear portion thereof in a tapered recess 38 in the receiver 12. When the action bar moves rearwardly, the bolt is cammed down by reason of the cams 35 on the engaging cams 37 in the bolt, and this causes the bolt to be pushed out of recess 38 and back, see the dotted lines, FIG. 2. The action bar thus unlocks the bolt from the notch 38 and moves it rearwardly, for the ejection of the spent case and the admission of a fresh cartridge into the receiver. The blow-back action aids this motion to some degree. The magazine and appurtenant parts are not shown herein as they form no part of the present invention.

When the action bar spring returns the action bar, the latter moves the bolt forwardly, and another action bar cam at 39 acts on cam surface 41 on the bolt to raise the rear end of the bolt into locked breech closed condition. The top of the cam 41 at 42 holds the bolt until the action bar once more retracts.

The `firing mechanism is shown in FIG. 2. This firing mechanism is located in general in a housing 50 mounted by any kind of bolts with respect to the receiver, one of these bolts being located at 52. Pivotally mounted at 54 is a disconnector bar or lever 56 which has a forward end portion or nose at 58 in the path of the action bar, see for instance 60, which depresses the disconnector at i-ts right-hand end portion at 58. Thus as the action bar retracts, it raises the other end at 59 for a purpose to be described, and releases it only at the extreme end of the forward travel of the action bar.

The hammer is indicated in general at 62. It has a hammer nose 464 and is pivoted at 66 in the housing 50. A spring 68 urges the hammer up to firing position. The sear is shown at 70. It has a sear nose '72 and is pivoted at 74. There is also a sear spring 716 tending to turn the sear in a counterclockwise direction. The hammer in the area near its nose has a cam surface 78 cooperating with a similar cam surface 80 on the sear nose, and it will be seen that the hammer 62 is caused to move in a clockwise or refractive direction under intiuence of the bolt, and when this happens the cam surfaces 78 and 80 engage causing the sear to move slightly in a clockwise direction against the action of the sear spring 76, so that the nose 64 snaps under the sear nose at 72 and the hammer is thereby held in the position of FIG. 2, ready to be released by the sear to fire the next shot.

There is a trigger indicated at 82 mounted on a trigger pin 84 and having a spring at 86 for maintaining it in its forward position in the trigger guard 88. The spring tends to maintain the trigger in this position and returns it to this position after the trigger has been pressed to release the sear. The trigger has an abutment at the lower end thereof as at 90 and there is a rectilinearly actuated safety device 92 which can be moved to safety position by pressing with the finger at the forward portion thereof and retracting the safety to the rear. As shown in dotted lines at 94, there is an abutment on the safety to engage the trigger abutment 90 and the trigger is positively held against firing thereby. It is only necessary to push forwardly with the foretinger in the trigger guard in order to release the safety.

At the end of the sear 70 opposite the sear nose, there is a shoulder 98 which is engaged by an inclined shoulder 100 on a sear latch or release member .102. The sear latch is pivoted at 104 and it holds the sear against the action of the sear spring, but is capable of moving in a countercloekwise direction under iniiuence of the trigger so that the inclined shoulder at 100 depresses the sear and causes it to move slightly in a clockwise direction, in turn causing the sear nose to slip off the hammer nose and allow the hammer 62 to move in its anti-clockwise direction under iniiuence of its spring 68 to strike the firing pin in the bolt. The sear latch 2 is retracted about its pin 104 against the action of its spring 106 by means of the disconnector end 59 which is in the form of a cam, engaging a iixed pin 107 on the latch. Thus the latch is completely free of the sear at all times except when the action bar is fully forward and the bolt thus locked. Hence the gun cannot be red unless the bolt is locked in Ithe breech. Also, the trigger upon being pressed, prevents the sear from re-engaging the hammer unless released. Hence, no premature firing is possible.

The new and improved breech-plug comprises a generally cylindrically member 108 which can be c-ut off at 110 to make the same conform to the general shape desired, and this member is pinned at 112 to a plug 114 screw-threaded into the breech end of the receiver as at 116. The breech plug member 108 abuts the receiver on a flat annular area 118, and pin 112 lies in an annular groove in the member y108.

It is recognized that breech plugs have to be turned up very tightly and when they are removed and replaced they are apt to vary in iinal position, but in the present case the member 108 abuts right up against the fiat at 118 at the rear end of the receiver, and then the screw 108 merely holds the same in position.

The sear spring impinges upon the top surface of the safety 92 and has a cap thereon which is indicated at 120. This cap fits into either one of two depressions at 122 and thus the sear spring tends to hold the safety in whichever position it is placed under manual pressure. The safety can also have a stop pin located in a groove as is shown at 124 to prevent over-riding.

Now referring lto FIG. 8, a modification in the bolt is here shown. The receiver is indicated by the reference numeral 126 and it is undercut or lnotched at 128 to receive an upstanding projection on the top of the bolt at 130, in which case the bolt is tilted and locked in breechclosed position. The interengagement between the bolt and the action bar is the same as before, but in this case the top surface of the bolt which is indicated at 132 is chamfered or rounded ofi? along a taper indicated at 134. As shown in dotted lines in IFIG. 8, the bolt moves back and forth but when the action bar brings it so that the projection at is in line with the notch 128, the cams mentioned above, as at 39 and 41, ensure that the bolt shall be moved up at its rear end into breech-closed and locked position, and in this case of course the rear end of the bolt is tilted upwardly from the bottom surface of the receiver.

The advantage of this construction is that it is easier to chamfer off the top of the bolt than it is to form the taper for recess 38 in the receiver which is shown in FIG. 2, and thus this results in a saving in the manufacture of the firearm. Insofar as the cams on the bolt are concerned, the numerals are applied to FIG. 8 the same as they are to FIG. 2, and it is believed that this will result in clarity of illustration.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

`1. A firing mechanism for a firearm including a barrel, a receiver thereon, a reciprocable bolt therein, an action bar for moving said bolt rearwardly to open the breech, a hammer, a hammer pin upon which said hammer is pivoted, a sear, a sear pin for the sear, said sear and hammer having interengaging means whereby the sear normally holds the hammer in retracted position thereof ready for tiring, a spring for said hammer to move it to firing position, and means to move said sear to hammer releasing position to allow said hammer spring to spring the hammer into firing condition, the distance between the sear pin and the hammer pin being shorter than the distance between the sear-hammer interengaging means and the hammer pin, whereby pressure of said hammer upon the sear under influence of said spring causes locking pressure on said sear rather than tending to move the sear to hammer releasing position, and a spring for the sear normally tending to urge the sear towards hammerengaging position and into the path of the hammer as it moves to cocked position, the hammer and sear having cooperating cam surfaces to allow the hammer to pass the sear so that the interengaging means can operate.

2. A firing mechanism for a firearm including a barrel, a receiver thereon, a reciprocable bolt therein, a hammer, a hammer pin upon which said hammer is pivoted, a sear, a sear pin for the sear, a spring for the sear urging the sear toward hammer engaging position in the path of the hammer, said sear and hammer having interengaging means whereby the sear normally holds the hammer in retracted position thereof ready for firing, and mating cam means to allow the hammer to pass the sear sutiiciently to cause interengagement of said means, a spring for said hammer to move it to firing position, and means to move said sear to hammer releasing position against the action of the sear spring to allow said hammer spring to move the hammer into tiring condition, the sear pin on which the sear pivots being in a position relative to the location of the interengaging means such that pressure of said hammer under influence of said hammer spring enhances locking pressure on said sear and prevents accidental discharge of the firearm.

3. A breech plug construction for the receiver of a firearm having a stock, the receiver having an opening at the rear thereof, in which said opening is defined and surrounded by a iiat face generally annular area, said breech plug construction including a generally cylindrical eX- posed member having a substantially fiat annular forward face adapted to be placed in contact with the fiat face at the opening, and a threaded breech plug threaded into the receiver in the area of the fiat faces, said breech plug having a head contacting, holding and clamping said member with its fiat face in flat clamped condition with respect to the 'at face at the opening of the receiver, said exposed member also having a stock contacting face generally at right angles to the annular forward at face, and a stock engaging pin protruding from said stock contacting face.

References Cited by the Examiner UNITED STATES PATENTS Herren 42-70 Horan 89-184 Reising 42-16 Klocker 42--17 Harvey 89-193 Simpson 89-193 Campbell 42-69 Janson et a1. 4217 Hailston et al. 89-193 Lochhead 89-193

Claims

1. A FIRING MECHANISM FOR A FIREARM INCLUDING A BARREL, A RECEIVER THEREON, A RECIPROCABLE BOLT THEREIN, AN ACTION BAR FOR MOVING SAID BOLT REARWARDLY TO OPEN THE BREECH, A HAMMER, A HAMMER PIN UPON WHICH SAID HAMMER IS PIVOTED, A SEAR, A SEAR PIN FOR THE SEAR, SAID SEAR AND HAMMER HAVING INTERENGAGING MEANS WHEREBY THE SEAR NORMALLY HOLDS THE HAMMER IN RETRACTED POSITION THEREOF READY FOR FIRING, A SPRING FOR SAID HAMMER TO MOVE IT TO FIRING POSITION, AND MEANS TO MOVE SAID SEAR TO HAMMER RELEASING POSITION TO ALLOW SAID HAMMER SPRING TO SPRING THE HAMMER INTO FIRING CONDITION, THE DISTANCE BETWEEN THE SEAR PIN AND THE HAMMER PIN BEING SHORTER THAN THE DISTANCE BETWEEN THE SEAR-HAMMER INTERENGAGING MEANS AND THE HAMMER PIN, WHEREBY PRESSURE OF SAID HAMMER UPON THE SEAR UNDER INFLUENCE OF SAID SPRING CAUSES LOCKING PRESSURE ON SAID SEAR RATHER THAN TENDING TO MOVE THE SEAR TO HAMMER RELEASING POSITION, AND A SPRING FOR THE SEAR NORMALLY TENDING TO URGE THE SEAR TOWARDS HAMMERENGAGING POSITION AND INTO THE PATH OF THE HAMMER AS IT MOVES TO COCKED POSITION, THE HAMMER AND SEAR HAVING COOPERATING CAM SURFACES TO ALLOW THE HAMMER TO PASS THE SEAR SO THAT THE INTERENGAGING MEANS CAN OPERATE.