Question 12 3AE01 - Third Assistant Engineer

The Correct Answer is B. ### Explanation for Option B (Fork and Blade) **Option B is correct** because "fork and blade" is the standard engineering terminology used to describe the set of connecting rods in certain V-type engines (especially large diesel engines, like those found in locomotives or marine applications) where two piston assemblies share a single crankpin. * **Fork Rod:** This rod is split at the crank journal end, creating an opening or "fork." It typically mounts directly onto the crankpin bearing. * **Blade Rod (or Plain Rod):** This rod is narrower and fits snugly within the gap created by the fork rod. It usually shares the bearing surface with the fork rod or runs on the outer surface of the fork rod's bearing shell. This design allows both cylinders in the "V" to connect to the same point on the crankshaft while maintaining the necessary offset. ### Explanation for Incorrect Options **A) hook and nail:** This is not standard terminology used in mechanical or diesel engineering to describe the interface or design of connecting rods. **C) left hand and right hand:** While some components (like pistons or valve train parts in opposing banks) may be designated left and right, this terminology does not define the functional relationship or unique design of connecting rods sharing a common crank journal. **D) male and female:** While these terms are used generally to describe mating parts in engineering (plugs and sockets), they are not the specific, descriptive names used for the specialized connecting rod design required to share a single crankpin bearing surface. The distinctive mechanical names are "fork and blade" or "master and slave" (articulated rods).