GB879030A - Improvements in trigger mechanisms for firearms - Google Patents

Abstract

879,030. Trigger mechanisms. OLIN MATHIESON CHEMICAL CORPORATION. July 28, 1959 [Aug. 4, 1958], No. 25902/59. Class 119. A trigger device for a firearm with a breech bolt 12 comprises firing means 33, normally cocked, on a main frame 16, an element 21 co-operating with the bolt to sense whether the latter is open or closed and indicate this by moving to an inoperative or operative position respectively on the frame, a sear 31 mounted on the element 21 operable to engage and cock the firing means 33 and a trigger 39 pivoted at 41 on the frame 16 which can only move the sear to fire when the element 21 is in its operative position. The element 21 is pivoted to the frame at 19 and is formed as a bridge at 24 to carry a pivot 29 and a stop plate 27 for the sear 31. The sear 31 engages in a bent 32 on the hammer firing means 33 to hold it in the cocked position against the force of a spring 46 (Fig. 1, not shown). Ends 42 and 43 of a spring 40 bear on the sear 31 and the trigger 39 tending to keeping them forward, the former against the stop-plate 27 and the latter ready for pressing. The spring 40 thereby tends to rotate the element 21 clockwise about its pivot 19. The spring 46 is stronger than the spring 40 and when the hammer is cocked its force on the sear tends to rotate the element 21 anti-clockwise, so that the forward toe 22 of the latter rises behind an action slide 11 on the bolt 12. If the bolt is not closed the toe 22 fouls the action slide and the hammer cannot be held cocked. If the toe 22 has risen fully behind the slide, a thumb-piece 23 protrudes as in Fig. 2, but can be pushed manually flush with the frame 16, to lower the toe 22, if the breech is required to be opened by hand, especially.