Patent GB-475553-A (GB)
Title: Improvements in or relating to hand grenades
IPC: F42B27/08
Filed: 1936-05-18
Abstract: 475,553. Hand grenades. STHYR, H. L., and STHYR & PARTNERS, Ltd. May 18, 1936, Nos. 14072/36, 32567/36, and 4118 /37. [Classes 9 (i) and 119] Relates to hand grenades of the kind in which the release of the striking pin is brought about by a movement of the shell or body of the grenade relatively to a handle or throwing part which occurs in the action of throwing the grenade. According to the invention, a grenade of this kind comprises a pivot pin attached to the throwing part of the grenade and engaging a bayonet slot formed in the body of the grenade or in a part attached thereto, a pair of selfreleasing gripper jaws mounted to rock on said pivot pin and a guide member normally constraining said gripper jaws to engage and hold the striking pin, the said bayonet slot having a transverse part into which the pivot pin is moved to render the grenade safe and an axial part into which the pin is moved to set the grenade to the firing position and permit the throwing part to move axially relatively to the body for the purpose of freeing the gripper jaws from the guide member and thereby releasing the firing pin. As shown in Figs. 1 to 5, the grenade comprises a body part 1, the lower portion of which fits into a container 5 which constitutes the throwing part, the junction between these parts being closed by a waterproof adhesive band 45. The base 1a of the body part is formed as shown and has an internal groove 6 which accommodates a beaded edge in the base of an inner tube 7, 8, 9. The container 5 is formed with a recessed cavity 11 in which is situated a trigger 12 which is mounted on the squared spindle 14 of the sealing plug 15 and is adapted to engage a curved spring member 13. The plug 15 has a headpiece carrying a transverse hinge pin 16 upon which jaws 17 are pivoted so as to be adapted to grip the tail piece 18a of the striking pin 18, the head 36 of which is formed with gas channels 36a. Plug 15 also has a circular shank 19 which passes through a key 20 fast with the base of container 5 and then through a rubber &c. washer 21 and metal washer 22. The key 20 is accommodated in a slot 20a cut in the innermost tube 25 and is employed to rotate this tube when the outer container is rotated. The tube 25 forms in its upper part a seating for the fuze unit 26, comprising a percussion cap 38, time fuze 39 and detonator 40, and is provided with an internal flange 27 to accommodate a spring 28. Below this flange the tube is provided with a cavity 29 in which the jaws 17 are free to slide. The lower wall of the tube 25 is provided with bayonet slots having transverse parts 30 and axial parts 35 at opposed points within which the pin 16 can move and from which it projects into slots 31 in the base 1a. The tube 25 is also provided with two opposed projections 32 operating in slots 33 in the base 1a, the slots 31, 33 entering an axial slot 34 down which the projections 32 and pin 16 can slide freely when the tube 25 and container 5 have been rotated to the position shown in Fig. 5 so that the container, together with the tube 25, can be withdrawn axially to insert, inspect or withdraw the fuze unit 26. When, however, the trigger 12 is moved by hand to the firing position, the vertical slots 34, 35 are brought into coincidence and the pin 16 is free to move downwardly therein. In this position, the projection 32 remains at the right-hand end of the slot 33 and the tube 25 is therefore locked in position in the body part 1 of the grenade. The spring 13 is provided with end notches 42, 43 corresponding to the safe and firing positions of the trigger respectively and an indicator pin 44 attached to the spring 13 is protruded through the side of container 5 when the trigger engages notch 43 so as to warn the user that the grenade is ready to fire. In throwing the grenade, the user grips the container, keeping the thumb during the backward swing on the body 1. On the forward swing, the thumb is brought on to the container and this is used as a sling to assist in urging the throw of the grenade forward. As the grenade is thrown from the container, the jaws 17 draw the striking pin 18 downwards, compressing spring 28 until the jaws pass beyond the limit of cavity 29 when they separate and release the striking pin which is urged forward by the spring 28 to detonate the percussion cap 38. Fig. 10 shows the invention applied to a stick type of grenade. In this construction, the body 1 is formed with a screwed extension 50 into which is detachably secured a tubular member 51 which is surrounded for the greater portion of its length by a wooden covering 52. The base 1a accommodates the percussion cap 38 whilst the striking pin 18 and spring 28 are housed in the member 51. The lower portion 53 of the handle is formed as a detachable unit corresponding to the container 5 and is adapted to fit over the lower end of the member 51. The portion 53 has the jaws 17 mounted therein on the pivot pin 16 which engages in bayonet slots 30, 35 in the lower end of the member 51.