DIN Standards Committee Optics and Precision Mechanics
DIN ISO 1413
Horology - Shock-resistant wrist watches (ISO 1413:2016)
Zeitmesstechnik - Stoßsichere Armbanduhren (ISO 1413:2016)
Overview
The term impact refers to a collision between two (or more) bodies in which forces act on each other for a short time. Any wristwatch can be subjected to impacts. It can fall down or hit obstacles such as door frames. In the context of this standard the watch collides with a wooden floor after a free fall from a height of 1 m, resulting in an impact effect on the watch due to the impact on the floor. Based on the theory of inertia, the hammer of the pendulum described in this standard, which is a moving body under the influence of gravity and has inertia, collides with the clock, which is at rest. At the moment of impact the clock is accelerated by the force exerted by the elastic impact of the hammer. The watch itself is thus set in motion and receives its own momentum. In the free-fall test, the watch falls from a support from a defined height. Gravity accelerates the watch in the direction of the impact surface. At the moment of impact the watch is subjected to a negative acceleration caused by the impact surface during the shock. The linear impacts exerted on the watch without a strap, as well as the free fall of the complete watch from a height of one meter, represent very high stresses for all components of the watch. Linear accelerations can be observed and measured depending on the total mass of the watch, its design, the geometry, the materials used and the functions required of the components. Therefore, any impact applied within the scope of this standard weakens the components considerably and brings them closer to a state of overload and ultimately to complete damage. This phenomenon as well as the consequences of a constant accumulation of stresses is the reason why the acceptance criteria shall be selectively applied and the after-effects considered after each test. This standard is intended to allow certified testing of watches (type testing) instead of testing all watches in a production batch. Assuming that each watch could comply with the minimum requirements without apparent damage, readjustment could still be made necessary because the test can lead to an alteration of the initial functions and rate of a complete watch. Users of the standard are primarily the manufacturers who provide the end user with a shock-resistant watch that is suitable for everyday use. This standard is a test standard. It also covers fundamental aspects of quality and product safety. The committee NA 027-04-08 AA "Uhren" ("Watches") at DIN is responsible for this standard.
