US2462889A

US2462889A - Cartridge case extractor

Info

Publication number: US2462889A
Application number: US574947A
Authority: US
Inventors: Graham B Neidhardt
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-01-27
Filing date: 1945-01-27
Publication date: 1949-03-01
Anticipated expiration: 1966-03-01

Description

March 1, 1949. ca. B. NEIDHARDT CARTRIDGE CASE EXTRACTOR Filed Jan. 27, 1945 GRAHAM :ELNEIDHAH'DTJ aamvh mw Patented Mar. 1, 1949 UNITED STATES PATENT OFFICE CARTRIDGE CASE EXTRACTOR Graham B. Neidhardt, Albion, Ind.

Application January 27, 1945, Serial No. 574,947

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 1 Claim.

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

The invention relates to cartridge case extractors.

In some guns such as the 20 mm. aircraft cannon, the standard extractor serves to aid in positioning the round as it is carried into the chamber by the bolt to prevent the round from entering the chamber too far, and to extract the round in case of misfire, it being understood that the extraction of the empty cases is efiected by the pressure of the gases as the bolt retracts.

The conventional extractor or that illustrated in Figure 1, is spring-operated and oscillates in its cavity in the bolt. It has a square or perpendicular inner lip which abuts the inner peripheral edge of the base of the cartridge when the bolt is in locked or firing position, there being a space between the face of the bolt and the cartridge base which is objectionable for reasons that will be stated, and which the present invention seeks to eliminate, and thereby improve the operation of the gun.

The lip of the conventional extractor does not maintain contact at all times with the rim of the cartridge, and the cartridge is free to travel with respect to the lip as in cases where the bolt, in

closing, is stopped by the face of the cartridge chamber or that part of the barrel that surrounds the chamber, the round continuing to move forward until the rim of the cartridge engages the inner lip of the extractor. This engagement, at times is with suflicient force to tear out a portion of the cartridge rim which may drop into the mechanism and cause malfunctioning of the gun. Again if the firing pin protrusion is the maximum allowable and the wall of the primer is the minimum thickness allowable, a punctured primer may result which is also objectionable and likely to cause malfunctioning of the gun by fouling the firing pin hole in the bolt and by particles falling into the mechanism.

The usual or spring operated extractor is so arranged with respect to the bolt that if the round in being fed gets ahead of the extractor the extractor may dip under the cartridge rim and spring into proper position.

The present invention contemplates an extractor which is made rigid with the bolt either by being made integral therewith or rigidly attached thereto, and provided with a lip having a positive angle, that is to say an inclined inner position so that when the round is stripped from the belt and fed into the chamber by the forward action of the bolt the base of the cartridge slips down the face of the bolt until its rim is caught by the extractor and when the round straightens out as it is chambered, the rim is cammed down the inclined lip of the extractor until the base of the cartridge is flush with the face of the bolt, thus closing the objectionable space between the bolt and the cartridge when the bolt is locked in firing position.

In the drawings illustrating the invention:

Figure 1 is a horizontal section of a portion of the breech of a gun with the breech bolt and extractor therein, in one of its positions relative to a round shown in the cartridge chamber, the arrangement being conventional.

Figure 2 is a similar view showing my improvement.

Figure 3 is a section of a forward end of the bolt showing a form in which the extractor is made separable from the bolt and held in operative position by suitably positioned pins.

Referring to the drawings and particularly Fig. 1, numeral I designates the bolt and 2 the conventional spring operated extractor, while 3 designates the breech portion of the gun. The extractor is rockably mounted in the cavity 4, upon pin 5, there being in the rear end of the extractor a socket 6, for the reception of a spring 1 exerting a tendency to normally raise the front end of the extractor. The lip 8 of the extractor is perpendicular or normal to the axis of the gun as indicated at 9 and lies flush against the rim ID of the cartridge when the bolt is in firing position, there being at such time a space I I between the face [2 of the bolt and the base of the cartridge case. This is usual and is the construction upon which I aim to improve.

My arrangement in its preferred form is shown in Figure 2 in which the extractor I3 is an integral part of the bolt and extends beyond its front end a distance about the same as that which characterizes the extractor shown in Figure 1. Beyond the making of the extractor rigid with the bolt the leading feature of the invention is, as intimated, the provision of a novel lip of the extractor, which I form with a positive angle [4 which functions as a cam to automatically cam the cartridge back against the face of the bolt and thus close the space between the bolt and the cartridge, so that when the bolt is locked in firing position the base of the cartridge is flush against the bolt. By this arrangement the distance between the end of the firing pin and primer of the cartridge is uniform and can be extending from the front of the bolt for a distance suitable for the accommodation of the: extractor. Transverse pin holes are provided in the bolt and adapted to register with corresponding holes '1! in the extractor, the holes being.forlthereception.

for pins 18 by which the extractor and bolt are rigidly united. An advantageof the structure is that the extractor is replaceable in case of injury or breakage.

As the cartridge base passes down over the face of the bolt in straightening out while being fed into the cartridge chamber, the rim of thecartridg'eengages the inclined lip 14 and will be cammed 1 back'againstthe front end of the bolt, Raga-inst which it remains until the round is fired. It will be noted that the type of cartridge case with which the extractor is designed to be used is constructed with a taper toward the front. This-permits considerable leeway and play until the moment when the cartridge is firmly seated. There is also a slight amount of play in the bolt and other parts of the gun, so that in practice no diificulty is encountered in obtaining the proper cooperation of the parts necessary for correct operation within the usual range of tolerances encountered; The radial distance between the center of the'gun bore and the bottom of lip M isso designed that with the usual tolerances the base of the cartridge is easily maintained, there being sufficient radial play under the worst permissible conditions to allow rim-l0 to move down to snug engagement with both face l2 of the bolt and cam surface [4 of extractor I 3.-

It should be noted in Figure 3 that the front face of the extractor lip I3 is rounded, which serves the purpose of allowing the cartridge case to be cammed into the proper position-inthe event that the round is ever fed ahead of the extractor, whichrarely occurs. This feature was successfully tested by the inventor who partially pre positioned a round in the chamber by hand and then released the bolt from a cockedposition.

The tare-positioned round was fired and extracted successfully.

not heretofore mentioned. The extractor'is much stronger at the base of the lip owing to the positive angle, than is the conventional extractor. Also, the integral extractor has neither extractor spring nor pin, which in the conventional extractor are subject to breakage.

Different calibers in various types of guns may make it desirable to vary the positive angle of the extractor depending upon the particular weapon. For instance, while a 45 angle in the illustrated example of the invention would be desirable in one "type of gun, a 15 angle may work better for another type of weapon, the object beingin all cases to eliminate the space between the face of the bolt and the cartridge When the bolt is locked in firing position.

I claim:

Inqa machine gun, the combination of a reciprocating bolt having a bolt face substantially perpendicular to the path of movement of the bolt and an extractor secured to said bolt, said extractor having a rigidandunyielding -extension projecting beyondthe face of the bolt in a direction parallel to the path of'movement of the" same, said extractor extension and bolt faceto; gether providing a groove with the openen'd, thereof directed toward the bolt axis, saidgroove" having theforwardly disposed side wall thereof bolt face.

GRAHAM B. NEIDHARDT;

REFERENCES CITED The following references are of record in the file -of this patent:

UNITED STATES PATENTS Number Name- Date 380,682 Holmes Apr. 10, 1888 J 1,200,685 Young Oct. 10, '1916 1,544,566 Eickhoff July 7,1925 1,628,226 Browning May 10, 1927 1,702,063 Swebilius' Feb. 12,1929 1,889,099 Loomis Nov. 29, 1932" FOREIGN PATENTS Number Country Date 1,093 Great Britain Apr. 10, 1869- 1,448 Denmark Jan. 29, 1898 13,117 Great Britain 1905' 637,801 Germany Nov.-4, 1936