What Is a Shock Guard?
A shock guard is a safety device used to protect machinery from overloads.
Also called an overload protection device, it is used in food and packaging production lines. Installed on a rotating machine, it prevents the machine from being damaged by excessive torque applied due to some abnormality in the machine.
It is attached to a gear called a sprocket, which transmits the rotation of a shaft to a chain. The shock guard can be set, and if the relative speed between the shaft and chain exceeds the set value, the shock guard will spin around.
Applications of Shock Guards
A shock guard is mainly used in the industrial field as a device to protect rotating machines from overloads.
When cutters are used on production lines, for example, high loads applied to the cutters can cause dangerous accidents. The use of the shock guard in the cutter drive unit increases safety against accidents.
A shock guard is also used in combination with a small shock guard when performing handling operations, such as mechanical handling.
Principle of Shock Guards
A shock guard consists of a bearing, flange, and drive the ball, and is effective when excessive torque is applied.
Under normal conditions, torque transmission is performed by the drive balls. The drive ball engages a pocket in the flange and is transmitted to the shaft as the flange rotates normally. Alternatively, rotation is transmitted in the opposite direction from the shaft to the flange through the ball. However, if an overload is applied, the ball is dislodged from its pocket on the flange.
The ball slides between the plate and the flange, preventing torque from being transmitted from the shaft to the flange. The torque threshold can be set arbitrarily in a shock guard.
If an overload occurs, the rotation is stopped to eliminate the cause. When the overload is removed, the ball and pocket will re-engage and the machine will operate normally (automatic recovery method).