For those interested in obscure British WWI grenades, a not-so-common experimental design created and patented (patent No. GB104539) by a London engineer, John Alfred Prestwich.
The images show various aspects of the grenade, comparison with a Mills No.5, and the grenade stripped down and labelled to correspond with the included detailed description of operation and corresponding drawing from the patent. The principle of operation was of a weight, or tumbler, that was unlocked on throwing, so that the shock of impact would dislodge the weight and allow the striker to fire a percussion cap above the detonator.
Essentially, to use, the safety pin and ring pull was withdrawn allowing the enclosed pin (t2) retaining the lever (t) to move out and free the lever. On throwing the grenade, the spring-loaded safety bolt (r) ejected, pushing away the lever. This unlocked the weight/tumbler (h), now only held by the collar of the spring-loaded striker (c) engaging the head (h1) of the weight spindle. The shock of the grenade landing caused the weight to dislodge and the striker to hit the percussion cap.
Needless to say the complexity of the item, and the extreme danger of a blind*, meant the grenade did not progress; the Mills time grenade was at no risk of replacement by the Prestwich.
* The Munitions Inventions Department decided fairly early in the development game that percussion grenades with spring loaded strikers were simply too dangerous to be adopted.
Tom.
The images show various aspects of the grenade, comparison with a Mills No.5, and the grenade stripped down and labelled to correspond with the included detailed description of operation and corresponding drawing from the patent. The principle of operation was of a weight, or tumbler, that was unlocked on throwing, so that the shock of impact would dislodge the weight and allow the striker to fire a percussion cap above the detonator.
Essentially, to use, the safety pin and ring pull was withdrawn allowing the enclosed pin (t2) retaining the lever (t) to move out and free the lever. On throwing the grenade, the spring-loaded safety bolt (r) ejected, pushing away the lever. This unlocked the weight/tumbler (h), now only held by the collar of the spring-loaded striker (c) engaging the head (h1) of the weight spindle. The shock of the grenade landing caused the weight to dislodge and the striker to hit the percussion cap.
Needless to say the complexity of the item, and the extreme danger of a blind*, meant the grenade did not progress; the Mills time grenade was at no risk of replacement by the Prestwich.
* The Munitions Inventions Department decided fairly early in the development game that percussion grenades with spring loaded strikers were simply too dangerous to be adopted.
Tom.
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