Patent GB-601594-A (GB)
Title: Firearm
IPC: F41A17/20
Filed: 1944-10-23
Abstract: 601,594. Smallarms. KEENE, S. I. Oct. 23, 1944, No. 20518. Convention date, Nov. 3, 1943. [Class 119] A firing mechanism for smallarms comprises an assembly of elements adjustably connecting the sear 22 with the trigger 4 for releasing the sear from its holding position with the firing pin or hammer either upon retraction of the trigger in the usual manner, or during its forward return movement after its release from finger pressure, a control member being provided for selectively adjusting the assembly to cause release of the sear during the desired directional movement of the trigger. As shown, the upper end of the trigger is slotted for the passage of an arm 31, and is formed with a cross member 52, this member and the walls 30 of the slot having apertures which register with two apertures in the sear 22. The aperture in the walls is in alignment with one in a bushing extending between the walls and on this bushing is a cam 53 to which arm 31 is connected. Permanantly connected to the trigger by a pin 55 is a block 26 which, as shown in plan in Fig. 5, has ears 27, 28 extending one on either side of the trigger. This block can be moved laterally of the weapon, by arms 60 under the control of an external handle on a shaft 67, so that either one of two pins 50, 51, extending inwardly of the ears can be made to project through the apartures in the upper part of the trigger and the sear. When the pin 51 is so engaged and the trigger is pulled, the trigger will first pivot on the sear about the pin until member 52 meets the top wall 9 of the casing 7 in which the mechanism is mounted, and thereafter the pin will move downwards taking the sear with it and releasing the nose 21 of the sear from the firing pin or hammer. When, however, arms 60 are moved to bring pin 50 into engagement with the sear and trigger, and the trigger is pulled, the trigger will pivot about pin 50, and the arm 31, which is constantly urged rearwards by a spring in its sleeve 41, will cause cam 53 to rotate in a clockwise direction to bring its high point extending upwardly. If, now, the arm, and hence the cam, are held and the trigger released, the trigger will pivot about pin 50 until the cam meets the wall 9 and further forward movement of the trigger causes the pin 50 to pull the sear downwards to effect firing. The device for holding the arm 31 consists of a lever 17 pivoted at 38 to an ear on a bolt 34 and carrying a notched member 81 which engages a cross member on the arm when the lever is depressed. The lever carries, about a pivot 95, a safety device in the form of a finger piece which is moved laterally by the pointed nose of a spring-urged member 92, such sideways movement preventing passage of the finger piece through a slot in a casing 16 when accidentally depressed. In use, a sideways exertion by the finger enables passage of the member through the slot and hence operation of the lever 17. The shaft for the control arms 60 has a spiral slot to produce the required transverse movement of the arms when the shaft is rotated, and carries a pivoted arm which can be moved into slots in the weapon to hold the parts in position when the pins 50, 51, are in either of their two operative positions, or in a third position, where both pins engage with the sear, thus preventing rotation of the trigger.