Patent GB-278087-A (GB)
Title: Improvements in sporting guns, rifles and the like
IPC: F41A3/58
Filed: 1926-06-30
Abstract: 278,087. Chevallier, A. L., and Churchill, R. June 30, 1926. Breech actions, drop-down barrel; single-trigger mechanisms. - A drop-down gun of the under- and-over type has an inertia block sliding on the locking bolts and carrying the percussion pins springs and sears, the block effecting the cocking of the percussion pins when the gun recoils. The block may also form an auxiliary locking device for the barrels. The sears are operated by a single trigger. Interengaging recesses and projections guide the barrels in the breech body during the opening and closing movements. As shown, the percussion pins 11, 12, Fig. 11, of an under-andover gun are mounted in an inertia block 1 mounted to slide forwards on the locking bolts 2, Fig. 7. The pins are held cocked by verticallysliding sears 15, 16, Fig. 9, carried by the block and operated by levers 59, 60, Figs. 3 and 17, mounted on a detachable trigger plate. When the gun is fired, the block 1 moves relatively forwards against the pressure of springs 8. Fig. 7, and the released percussion pin is pressed back by a lever 37 or 38, Fig. 11, which is pivoted on the block 1 and engages the back of the standing breech 5. The point of contact of the lever with the standing breech is midway between the pivot and the end engaging the percussion pin so that the pin is moved back twice as far as the block moves forward. The block is attached to a cover 46, Fig. 4, the internally bevelled front end of which, when the gun is fired, engages a projection 47 on the barrels with a binding fit and holds the barrels locked. To unlock the barrels, the inertia block is pulled back by means of an external lever 33, Fig. 1, mounted on a spindle in the block and adapted to engage a fixed projection 36 on the body. The locking bolts 2 are carried back by the inertia block, the barrels being thereby unlocked. Undesired rearward movement of the block is prevented by a safety catch 82, Fig. 6, which is pressed in, when the lever 33 is depressed, to bring a projection 83 on the catch opposite a recess 84 in the block. To cock the percussion pins initially, the lever 33 is rotated so that a cam 30, Fig. 11, on the spindle 31 retracts a cocking slide 28. The trigger mechanism comprises a single trigger 69<3>, Figs. 3 and 17, carried by a swinging beam 71. mounted to turn about a vertical pivot 74 at the rear to bring a pawl 67 on the trigger blade alternately into engagement with shoulders on the two sear-operating levers 59, 60. When the first barrel is fired, the beam is swung over by a spring 76 to bring the trigger into position for the second shot, and the connection between the sear-operating levers and the sears is temporarily broken so that the involuntarily pull is ineffective. The trigger mechanism is reset when the gun is unlocked. The ejectors 55, Fig. 4, are operated by studs 56 on the ejectors engaging cam surfaces 57 and projections 58 on the action body. A safety slide 85, Fig. 1, operates a bolt 91 adapted to pass through a slot 93, Fig. 11, in the end plate of the inertia block and lock the sears. The barrels are gmded in the breech body by recesses, in the sides of the lumps, engaging projecting plates 53, Fig. 1, detachably secured to the side plates of the action body.