Which of the following devices are commonly used as overload safety mechanisms in farm machines such as PTO drives, rotavators, and balers?
Options:
(A) Shear bolt / shear pin
(B) Slip clutch (friction plate clutch)
(C) Radial pin / star ratchet clutch
(D) Solid sleeve muff coupling
Answer Key:
A, B, C
Step-by-Step Solution & Explanation
Safety overload devices disengage or slip when torque exceeds the safety limit:
- **Shear bolts** fail under critical shear to protect the drive line.
- **Slip clutches** allow friction discs to slip under peak shock loads.
- **Star ratchet / radial pin clutches** disengage against spring load.
- A solid sleeve muff coupling is a rigid coupling that provides no overload slip protection.