GB135469A - Improvements in or relating to Breech Loading Guns. - Google Patents

Abstract

135,469. Asbury, D. F. Nov. 16, 1918, [Convention date]. Ordnance breech mechanism; machine guns.- Consists in a means for utilizing the energy stored in a longitudinally-sliding and rotatable breechblock or bolt during unlocking to effect automatically the breech opening, closing, and locking movements. Figs. 1 and 4 are respectively a sectional elevation and sectional plan of a recoiling- barrel gun with the breech closed. Fig. 7 is a cross-section on the line 7-7, Fig. 1, and Fig. 12 is a perspective view of the rear end of the gun. The breech-bolt B is locked in the closing position by two lugs 22 which engage with corresponding lugs in the barrel extension 11. Rotation of the breech-bolt in either direction serves to unlock the bolt, and, in the form shown, automatic unlocking is effected in one direction and manual operation, by a handle 48, in the opposite direction. The locking rotation is in the same direction as the automatic unlocking rotation in both cases. The enlarged rear portion of the breechbolt is provided with an unlocking cam 21 on its underside adapted to coact with a roller 40 carried by a detachable plate 34 fixed to the non-recoiling cradle 10. The roller spindle 39 may be inserted in any one of a series of holes 36-38 in the plate so that the point in the recoil stroke at which unlocking occurs is regulable. The breech-bolt also carries a roller 47 which is constantly engaged in a continuous cam-groove D in the barrel ex. tension. The cam-groove D comprises longitudinal portions 45, 46, one in each side wall of the barrel extension 11, connected by semicircular transverse portions at each end, the transition curves being as shown at 41, 42, 43, Figs. 1 and 12. The unlocking rotation of the breech-bolt causes the roller 47 to travel down the curve 41, by which the rotary movement is converted into a rearward opening movement of the breech-bolt. At the rear end of the groove 45 the roller travels up the curve 42 and through the semicircular bridge portion of the cam-groove, thereby stopping the rearward motion of the bolt and converting it into rotary motion again. The energy stored in the bolt is such that when the roller meets the curve 43 the bolt is pushed forwards again, the roller meanwhile traversing the groove 46 until the last transition curve is encountered, when the locking rotation is imparted to the bolt. A tappet 50 on the handle 48 engages the first roller 40 when the breech-bolt is locked and prevents automatic unlocking until the barrel and breech-bolt have recoiled a certain distance after firing, but does not prevent hand operation in the opposite direction. The ejector C has two lateral projections, as shown in Fig. 4, which engage grooves extending half way around the head of the breech-bolt. The rear groove 26 has forwardly enlarged portions 27 at its ends which permit the ejector to be thrown forwards when it strikes a fixed stop 31 at the end of the breech opening movement. Specification 134.530 is referred to.