The Spring Hammer consists of three principal parts : the body, the
striking element and the release system.
The body comprises the housing, the guide for the striking element, the
release mechanism and all parts rigidly fixed thereto.
The striking element comprises the hammer head, the hammer shaft and
the cocking knob. The mass of this assembly is 250 g for severities not
exceeding 1 J, and 500 g for 2 J.
The pressure to release the striking element will not exceed 10 N.
The configuration of the hammer shaft, the hammer head and the means
for the adjustment of the hammer spring is such that the hammer spring
has released all its stored energy approximately 1mm before the tip of the
hammer head reaches the plane of impact. For the last millimeter of its
travel, prior to impact, the striking element is thus, apart from friction, a
freely moving mass having only kinetic energy and no stored energy.
Moreover, after the tip of the hammer head has passed the plane of
impact, the striking element is free to travel, without interference, over a
further distance of between 8mm and 12mm