adjustable crank pin的用法和样例：
- Examine carefully the crank pin for flaws or hair cracks.
- The beam and crank pin bearing adopt tip bearing structure to decrease the shaking due to the install difference and operation of pumping unit.
- The undersigned did deem that if the non-parallelism of the crank pin exceeds permissible limitation, crank pin and bearing were caused to be burnt.
- The main causes is analysed for looseness of the threaded connection on pumping unit crank pin and the corresponding preventive measures are proposed.