|Drawings from Les Grenade Allemandes de la Grande Guerre, Patrice Delhomme
On the eve of the Great War grenade technology was at a primitive level. The classic cast iron sphere was little changed from its 17th century inception.
As the trench war progressed distances between opposing forces became ever smaller, the ability to attack your opponent without the requirement of direct line of site was a great advantage. Hand grenades became an indispensable weapon and development proceeded at a furious pace.
Early designs ranged from simple ball grenades such as the Kugel to complex types such as the Austrian Universal. Stick grenade types became increasingly popular and appeared in a bewildering variety of styles.
Shown here are the improvised French Pétards Raquettes, and an Austrian rifle grenade reconfigured as a stick grenade.
Time fuze technology was crude and delay times needed to be at least five to seven seconds for safety reasons. However, when thrown at short range, there was too often time enough remaining on a burning fuze to allow a soldier to pick up and throw the grenade back. A fuze that would explode on impact was highly desirable and many designs were tried, but few (if any) achieved any significant degree of success.
By 1915 the Germans introduced their first regulation stick grenades, with the now familiar metal can of explosive attached to a stick handle, equipped with delay fuze activated by a pull cord lanyard. By 1916 German stick grenade production alone was eight million per month! At least 20 different stick grenade designs and variations were fielded by Germany from 1914 to 1917.
(Left to Right)
Model 1915 impact grenade; Two variations of the Model 1917; The classic WWII era Mod.24 (Dated 1939)
(Note: The M1915 at left is a restored relic - Repainted.)
Improvements in explosives allowed the size and weight of the warhead to be reduced, resulting in a less cumbersome design but maintaining the same blast effect.
The massive Model 1915 lever style impact grenade (far left) was heavy by design however. The fuze mechanism is similar to the one found in the Lanz mortar. It is a "allways" type which functions no matter what the orientation at impact, but was most sensitive when the grenade dropped head first. The massive sheet steel can was supposed to help insure that result, but it wasn't very successful. This lead to a design modification using a heavier cast iron Kugel body instead, but evidently this wasn't much of an improvement and the grenade type was withdrawn from service.
|Impact Fuze Function
The large lever pivots on an axial pin. As a spring pushes the bottom up, the front claw is pushed down on a smaller lever arm. That small lever, also mounted on an axial pin rotates in turn and pulls a safety bolt out, which unlocks the internal fuze mechanism. Impact forces the pellet and primer together, overcoming a creep spring. The primer fires, igniting the detonator which explodes the grenade.