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Теги: weapons military affairs patent
Год: 1947
Текст
Aug. 12, 1947, 2,425,684 G. W. PATCHETT BREECH BOLT FOR FIREARMS 2 Sheets-Sheet 1 Filed Feb. 7. 1944 Attorneys
Aug. 12, 1947. G. W. PATCHETT BREECH BOLT FOR FIREARMS Filed Feb. 7, 1944 2,425,684 2 Sheets-Sheet 2 A Homey s
Patented Aug. 12, 1947 2,425,684 UNITED STATES PATENT OFFICE 2,425,684 BREECH BOLT FOR FIREARMS George William Patchett, Chigwell, England Application February 7, 1944, Serial No. 521,402 In Great Britain October 25, 1943 4 Claims. 1 This invention relates to improvements in con- nection with firearms and has more particular reference to breech blocks or bolts used in such arms, and finds particular use in automatic weapons, that fill a military necessity between the rifle and the pistol. In such weapons the breech block or bolt, hereinafter referred to as the bolt, with its firing pin explodes the cartridge, provides the abutment for reaction of the ex- ploded charge and in turn and under recoil moves rearward in the bolt race against resilient pres- sure to repeat or be latent to repeat the same operation again. It follows that unrestricted movement in its race is essential for operation, and, whilst such movement may be prevented in design by a sear under manual or selective con- trol, adventitious material such as sand, mud or dirt can also provide a total impediment to move- ment, particularly when the arm is used in desert warfare or when the weapon has been in contact with mud, dust, sea water, or exposed to tropical rain or mist. The entry of adventitious material to the bolt race is facilitated by direct openings or passages thereto. Thus, the axial slot of the cocking device, the aperture of the ejection orifice and the magazine mouthpiece itself all communi- cate with the bolt race. Additionally, the trigger seldom has a dust-tight arc of movement, and sand in a sand storm will penetrate at any open- ing however minute, and all such matters tend to detract from the readiness or reliability of the weapon to operate at instant call. The object of the present invention is to over- come these difficulties and to render the bolt self- clearing in its backward and forward movement and to provide a positive tendency to eject any adventitious lodgment. The invention consists in the combination with a bolt as employed in firearms of the types set forth of raised bearing surfaces or lands formed upon the said bolt and adapted to engage upon their outer surfaces with the inner surface of said bolt race, said lands having pointed or like ex- tremities formed to clear a gritless surface for subsequent continuous or other movement. The said lands are arranged helically on the periphery of the bolt, and are provided with pointed or plough-shaped extremities, fore and aft. The number of said bearing surfaces or their width may vary, and to prevent undue wear, and for other reasons more fully set out hereafter, the lands are formed as a helix upon the bolt’s longi- tudinal circumference, or right or left handed helical lands may be used so that any tendency for the bolt to have angular movement as with a (CI. 42—16) 2 helical land of unidirectional pitch, may be avoided. Since the movement of any bolt with helical lands will expose the land edges to the axial cock- 5 ing lever slot or the like, impurities will tend to be ejected. In less positive degree foreign mat- ter displaced by reciprocation of a bolt with the sharp nosed axial bolt lands is also ejected through one or other, or all, of the several open- 10 ings or passages in the bolt race. In order that the invention may be more fully and particularly described, reference is made to the accompanying drawings wherein the inven- tion is illustrated as applied to a known type of 15 automatic firearm, and wherein— Fig. 1 is a longitudinal section of a bolt and a bolt race, showing one form of the invention. Fig. 2 is a section on the line 2—2 in Fig. 1. Fig. 3 is an elevation of a bolt with two-start 20 helical lands. Fig, 4 is an end view of Fig. 3. Fig. 5 is an elevation of a bolt with two-start reversed helical land. Fig. 6 is an end view of Fig. 5. 25 Fig. 7 is an elevation of a bolt having four lands arranged helically so that their ends are in line or overlap the opposite end of the adjoining land. Fig. 8 is an end view of Fig. 7. In the drawings the bolt i may be of any re- 30 quired pattern; it may be pertinent to rifles or to automatic arms. The particular form shown is suitable for automatic weapons and is given by way of illustration only. Referring to Figs. 1, 2, 7 and 8, the raised bear- 35 ing surfaces or lands 2 are formed or applied helically to the axis of the bolt i, and leave spaces 3 intermediate between the bolt body perimeter 4 and the bolt race or casing 5 (see Figs. 1 and 2). The spaces 3 are made sufficiently large for rm- 40 wanted intruding matter to have free movement, with opportunity, under disturbance, of escape through the slot 6 (see Fig. 1) of cocking lever 7 fixed to the bolt (see Fig. 2) or other opening communicating with the bolt race. The extremi- 45 ties 8 of the said lands or raised portions may be curved from both sides as shown at 8 in Fig. 7, or be of coned appearance, or chisel shaped as shown at 82 in Figs. 3 and 5, to provide a con- tour for shearing and clearing, for instance, dried 50 mud from the bolt race 10. Figs. 3 to 8 inclusive show the raised surfaces or lands helically cut on the bolt periphery. This arrangement provides for cylindrical wear of the bolt race, and equally assists in quickly convey- 55 ing unwanted matter to the longitudinal opening
2,425,684 3 Б. If helical lands of unidirectional pitch are em- ployed as shown at 2 in Figs. 7 and 8 or at 22 in Figs. 3 and 4, the compression spring 12 may be wound to resist any tendency of the bolt to turn about its axis or press the cocking lever 7 upon the upper or lower edge of the slot 6. Should in some arms this prove difficult, then two-start right and left handed helical lands 2b (Fig. 5) may be formed upon the bolt periphery, gaps I i, (Fig. 5) being cut at the crossings for matter otherwise wedged in to escape. In operation and whether the bolt is cocked or not, movement of said bolt by recoil, spring or hand manipulation, clears by a shearing action the bolt race face 10 of adherent or loose ad- ventitious matter, which, being disturbed, is then free to escape from the opening whereby it en- tered or any other opening available. It is found that weapons not constructed in accordance with this invention, and which have been immersed in mud, when warm, will fail, since the heat of the weapon solidifies the earth matter on the surface of the bolt race. By means of the prevent invention, however, a clean path is cut by the initial longitudinal movement of the bolt, rendering subsequent movement a certainty. I claim: 1. A firearm comprising, in combination, a bolt race having a longitudinally continuous interior surface and a longitudinal slot in a side and open to the exterior thereof, and a breech bolt recipro- cable longitudinally in said race and having a cocking handle connected thereto and extending through said slot to the exterior of the race, the breech bolt having lands extending helically on and. projecting from its periphery and providing 5 10 15 20 25 30 35 4 peripheral bearing surfaces which slidably engage the interior surface of the bolt race to support the breech bolt therein and clear foreign matter from said surface, said lands providing a space between them to receive foreign matter cleared from said interior surface and communicating with said slot in the bolt race for conveyance of such foreign matter thereto. 2. A firearm as defined in claim 1, wherein said helical lands have unidirectional pitch along the periphery of said breech bolt, and said cocking handle engaging in said slot in said bolt race prevents rotation of said bolt in said race. 3. A firearm as defined in claim 1, wherein said helical lands have respectively relatively reverse pitches along the periphery of said breech bolt, and have ends which are spaced apart to leave openings between them. 4. A firearm as defined in claim 1, wherein said helical lands are arranged in a pair and are re- spectively at diametrically opposite sides of the periphery of said breech bolt. GEORGE WILLIAM PATCHETT. REFERENCES CITED The following references are of record in the file of this patent: UNITED STATES PATENTS Number Name Date 1,083,384 Browning_____________Jan. 6, 1914 1,586,048 Schmeisser___________May 25, 1926 2,049,776 Hyde-------------------Aug. 4, 1936 2,096,028 Burton et al._________Oct. 19, 1937 1,291,689 Sheppard______________Jan. 14, 1919 1,470,029 Pedersen_______________Oct. 9, 1923