The second half of the task was open-ended, which asked us to design a locking/breaking mechanism used under the assumption of turning off the power source. This design will resist moderate torque so that users can use the electric screw driver manually. The locking component we design was a custom machined gear consists of internal gear profile inside and spur gear profile outside. This custom made gear will wedge itself to the planetary gear train, when activated by pushing on the sliding button. The button and the custom made gear are simply connected together by a rigid linkage, which is press fit into the extruding flange on the custom made gear.

Aside from operation of the design, strength and weaknesses are laid out as following. The design may not be inexpensive thanks to using component of that custom machined gear. However, it is feasible and space-efficient in spite of its slightly high cost. The design can be fit in the original housing without adding too much modification to the original design. However, the extruding flange on the custom machined gear has a curvature surface, at which press fit of the linkage shaft will be more difficult than we expected. Reinforcement needs to be added on the flange in order to maintain the durability of our proposed design mechanism.