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and predictable tolerance. They are almost maintenance-free and can remain ready for operation for years with little to no decrease in reliability. Shear pins are only useful for a single operating cycle, after each operation they have to be replaced. A very simple example is the plastic or wire loop affixed to the handles of common
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Their high reliability and low cost make them very popular for use in weapons. A typical example is using shear pins in an explosive device. A shear pin can here hold a striker pin in place, preventing the striker pin from striking an initiator (primer) unless the correct force is applied. That force
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In the role as a conditional operator, a shear pin will be used to prevent a mechanical device from operating before the criteria for operation are met. A shear pin gives a distinct threshold for the force required for operation. It is very cheap and easy to produce delivering a very high reliability
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is usually selected to make the construction resistant to damage. This can for example be achieved by giving the material a high degree of elasticity so that, like a spring, the metal returns to its original shape after being deformed by an external force. A shear pin however is often tempered to
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Many designs take advantage of the maintenance-free state of constant readiness. For example, a hydraulic damper protecting a structure from earthquake damage could be secured with a shear pin. During normal conditions the system would be completely rigid, but when acted upon by the force of an
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being launched. The force would snap the shear pin, allowing the striker pin to move backwards onto a primer, which in turn ignites a pyrotechnic delay composition for auto destruction. In this use shear pins prevent the striker pin from hitting the primer during handling or if the grenade was
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is a mechanical detail designed to allow a specific outcome to occur once a predetermined force is applied. It can either function as a safeguard designed to break to protect other parts, or as a conditional operator that will not allow a mechanical device to operate until the correct force is
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The pin itself may be as simple as a metal rod inserted into a channel drilled through two moving parts, locking them in place as long as the pin is intact.
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rod inserted through a hub and axle; the diameter of the rod, alloy and tempering of the metal, are all carefully chosen to allow the pin to
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in the case of a mechanical overload, preventing other, more expensive or less-easily replaced parts from being damaged. As a mechanical
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A sailor checks the outside diameter of a shear pin in the machinery repair shop aboard US aircraft carrier
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A shear pin could potentially be made from any material although metal is the most common.
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The material of a shear pin is selected and treated so that it is relatively resistant to
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earthquake the shear pin would break and the hydraulic damping system would operate.
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In the role of a mechanical safeguard, a shear pin is a safety device designed to
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dropped by accident. Additionally, shear-pins are frequently used in
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When making a metal object for a mechanical application, an
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in
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