GB445213A - Improvements in automatic guns - Google Patents

Abstract

445,213. Machine guns. TENNANT, W. J., 111, Hatton Garden, London.- (Werkzeug - Maschinenfabrik Oerlikon ; 155, Birchstrasse, Oerlikon, Z³rich, Switzerland) Dec. 6, 1934, No. 35094. [Class 92 (ii)] Relates to sear mechanism for retaining the breech block 2 in the open position against the action of the return spring 3, the sear 4, during continuous firing, being movable entirely out of range of the breech block. According to the invention, the sear is held in engagement with the co-operating abutment 9 on the breech block by retaining means, and the abutment face 11 is inclined from the front rearwardly so that on release of the retaining means the sear is thrown off the abutment by the force of the return spring. In the form shown in Fig. 1, two sears 4, pivoted at 5 to a frame 6 sliding against the action of a buffer spring 8, are held in engagement with the breech block abutment 9 by spring thimbles 16 bearing on a sliding release rod 13. On pulling the rod against the action of its spring 18, the thimbles are released for inward movement and the force of the return spring 3 acting through the inclined abutment faces 11 throws the noses 20 of the sears outwardly, springs 19 serving to keep them out of the path of the breech block until the rod 13 is released when the breech block can re-engage the sears. Fig. 6 shows a modification in which the sear 4 pressed outwardly by a spring 19 is retained in engagement with a pivoted resilient abutment 36 on the breech block by a cam 13a which is rocked in the direction shown to cause release of the sear by the pressure of the return spring on the abutment face 11. When the breech block returns to the rear after release of the cam 13a, the incline 10 on the abutment rides over the surface 12 on the sear and the abutment again engages the sear. The abutment is connected to a sleeve 40 sliding on the rear of the breech block against the action of the buffer spring 8.