US2538048A - Operating slide for firearms - Google Patents

Description

Jan. 16, 1951 I w. A. scHAlcH Patented Jan. 16, 1951 UNITED sTATEs PATENT oFFicE- 2,538,048 OPERATING S LIDE FOR FIREARMS Wilbur A. Schaich, Highland Park, Mich.

Application November 10, 1948, Serial No. 59,325

3 Claims. (Cl. 89-129) (Granted under the act of March 3, 1883,' as

amended April 30, 192'8; 370 O. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes without payment of any royalty thereon.

- This invention relates to an improvementI in firearms, more particularly to improving the timed opening of an automatic firearm bolt.

In many firearms of the automatic or semiautomatic type the timing of the action is such that the breech closure member or bolt opens under relatively high residual breech pressure. Opening under such a condition adversely affects the firearm by producing excessive forces on the recoiling parts, harder extraction of the fired case due to its expanded condition and hence greater possibility of fracture of the extractor and the moving components of the action.

This condition is commonly found in the U. S. carbine, caliber v.30, M1 wherein the gas utilized to actuate the Operating slide of such firearm is tapped from the barrel at a point quite near the chamber hence where the breech pressure is exceedingly high. The tappet type actuation of the Operating slide coupled with a short dwell travel of such slide before Contacting the bolt lug cam results in the repeated unlocking of the bolt or breech member before the Chamber pressure has dropped to the proper level for safe opening of the firearm bolt. i

Various modifications have heretofore been utilized in order to delay the opening of the bolt of the above mentioned firearm. One of such 'modifications was to increase the dwell portion of the Operating cam contained in the bolt handle of the inertia slide and another was to increase the weight of the inertia slide. Neither of these modications satisfactorily accomplished the desired end. Increasing the weight of the Operating slide, while slightly delaying the opening of the firarm bolt, added materially to the weight of the firearm. Increasing the dwell portion of the Operating cam proved unsatisfactory and impractical due to design limitations required to maintain interchangeability.

Accordingly, it is an object of this invention to provide an improved firearm of the gas operated, automatic type characterized by the delayed unlocking of the bolt member to insure that the breech pressure has dropped to a safe level.

A further object of this invention is to provide means whereby the dwell period of an Operating slide of a firearm may be readily increased without major redesign of such firearm to delay unlooking of the firearm bolt until a desirably low and safe breech pressure is reached.

A particular object of this invention is to pro- Vide an improved inertia slide for an automatic firearm of the type similar to the U. S. carbine, caliber .30, M1, whereby improved timing of the opening of the bolt is achieved.

The specific nature of the invention as -well as other objects and advantages thereof will clearly appear from the following description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. l is a'fragmentary top elevational view of the receiver end of a firearm embodying this invention, showing the battery position of the improved inertia member and also the recoil positionlof such member in dotted outline.

Fig. 2 is a fragmentary side elevational view of the firearm of Fig. l shown with the stock removed to better illustrate the improved inertia slide.

Fig. 3 is a longitudinal sectional view taken along the line 3-3 of Fig'. 2.

In Figs. 1 and 2 there is shown a firearm embodying this invention. While not limited thereto, this invention is shown as embodied in a gas operated, automatic firearm of the type known as the U. S. carbine, caliber .30, M1. Such a specific example is merely chosen for purposes of illustration, as obviously this invention can be applied to any gas operated firearm having a reciprocating Operating slide or breech actuating member. The firearm shown in such figures comprises mainly a receiver I, a barrel 2, an Operating slide 3 and a stock 4 housing such members.

Barrel 2 is Secured to receiver I and operating slide 3 is mounted on barrel 2 for longitudinal reciprocal movement in the usual manner. However, slide 3 is formed in two pieces, a substantially rectangular shank portion lll, and ahandle portion 5.

Such handle portion 5 Vtelescopes into a hollow bar-like member 6 projecting rearwardly from inertia portion IG and integrally formed therewith, as will be presently described. A plunger 'I surrounded by a spring |5 is provided to bias slide 3 forwardly to battery position. The for- Ward end of plunger 'l abuts the rear surface of portion [4 while the other end of spring biased plunger l is contained within a suitable recess provided in receiver I. Handle portion 5 provides the usual Operating connection to a bolt 8 slidably contained within receiver l. A bolt lug (not shown) engages a suitable cam slot in the inside face of handleV portion 5, likewise not shown.

Handle portion 5 is provided with a forwardly projecting integral bar-like end l0 which is Each end of pin [3 is preferably peened, as,

shown in Fig. 3, to permanently secure such pin in bar 6. When Operating slide 'is inv it'sbattery' position on the firearm, as shown inFigs. 1 and2, the portion 14 is effectively separated from handle 5 by virtue Of slot ll. separation is here shown as limited to approximately One-half inch, although greater or lesser separation may be easily attained' by lengthem'ng.

or decreasing the length Of slot I l. Spring biased plunger 1 maintains the two parts of the operating. slide in such. separated position until discharge of a cartridge as will be presently described.

When a cartridge is fired in the firearm. the actuating gases impinge on a gasactuating mechanismL (not shown) which. in turn imparts-arearward blow to slide 3, thereby driving such slide rapidly rearwardly. The portion lll of slide 3 travels a substantial distance, bar portion telescoping into recess 9 of bar 6. before the rear end4 Of bar 6- effectively. engages handle portion by striking. shoulder. Illa.

Upto the. time such impactoccurs; nO-unlocking. movement of the. handle portion 5 of bolt 8' has taken place. In Other words, the: bolt 8: is securely looked to the receiver I- duringthe initial rearward travellof inertia portion 14 of .the.slide= Obviously this introduces; a4 substantial delaythereby providing more time for reduction of. pressureV in the barrel..

When the rear end of bar. 6 strikeshandle portion 5, such handle is moved rearwardly, thereby adding the usual time delay or dwell periodincorporated in the unlocking cam (not shown) to that,- obtained by telescoping the. inertia. slide. Atlthe termination of thesecondary dwell movement of the handle portion 5, the looking lug of the bolt (not shown). is rotated by thev cam; slotv (not. shown) contained in the handle portion: 5tO effect unlocking of such bolt from receiver. L Due to the momentum Of inertia=slide 3v andV to residual gas pressure in= the chamber, bolt 8 is driven rearwardly to4 its recoil positionas shown in dotted Outline in Fig. l.

From; theforegoing description itis thus seen that an. added. time lag Or dwelly period is introduced, prior to Opening of the firearm: bolt by meansof the telescoping Operating slide providedby this invention. The time lag between firing ofthecartridge and unlocking of the/bolt-so-introduced. plus. the. normal dwell, period of.. the unlocking cam of the Operating slide. provides ample. time for lowering of the breechpressure to. alevel. permitting safe: opening of the bolt.

The. amount of such.

When the bolt is unlocked under relatively low chamber pressure the fired cartridge case is easily extracted and the recoil forces acting on the receiver and moving parts are greatly reduced. It is further desired to point out that the means provided by this invention for achieving any additional time lag or dwell period to improve the timing of the opening of the firearmf bolt, is achieved in a simple manner which is inexpensive to: manufacture and easy to produce, does not require modificaton of the major components of the firearm; and may be interchangeably applied to existingfirearms merely by substitution of the Operating slide. Furthermore, the telescoping 'two part Operatingv slide does not impair the manual operation of the Operating slide.

I claim:

1:. In an: automatic' firearm with a reciprocable bolt-and a gas Operating mechanism, an Operating slide having two parts, a first part serving as an inertia device andv engagingthe gas Operating mechanism andasecond part engaging the bolt; and time. delay means connecting the' twolparts; said time delay means comprising. a-rod-'-like:eir-V tensionLL on one part carrying an inclosed rectangular slot, a pin rigidly se'curedl tO- the: other: part engagingthe slot; and? recessed meanssirr'the said'other part slideably receiving'the rOd.-like'.extension and thereby4 permittingf limited telescopic motion of the Operating slidel when the. inertia part is actuated.

2. A two part operatingtslide for azgasfoperated firearm With a reciprocable' bolt comprisin'gf.y a: forward shank part servingi as:an inertia device;v a rearwardv handle part; and: time delay-1 means' connecting the forward .and rearward partsf and preventing prematureV action of the handle. part; said time delay means compri'singi a= rod-likefextension Onthe handlepart'carrying: arr inclosed rectangul'ar slot, a pin-'rigidl'y securedtoftheshank' part engagingv the slot, anda. bore in' the shank part slideably receiving the rod-likeI extensionand thereby permitting' limited' telescopi'c" motion? of' the Operating slide when' the in'ertiaA part'is actuated.

3. An Operating slide.- as in cliaim 2 inwhich' the pin of the time delay means extends tfrans versely through the rectangularsslot* andlrtr-avel longitudinally thereifn.

WILBUR SCHIA'ICHI REFERENCES CITED- Thev following references are of recordA in'V the file of this* patent:

UNITED STATES PATENTS.

Number Name Date:

577,485 Maxim'- Feb-23; '18974 70.9;880 Knight' Sept. 30, 1902 799,884' Augezd Sept;,19;'1905 2356,,595 Koucky Aug; 22;- 1944' 2,45l',624 Loomis et al, Oct2.-19,.I94'8

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