A mechanism for selectively coupling a first moving part with a second moving part. The mechanism includes and engaging member that is movable between a detent position, a uncoupled position, and a coupled position in which the load transferring surface is within the aperture. A biasing member biases the engaging member into the detent position or coupled position. The engaging member overrides the biasing force and moves out of the detent position into the uncoupled position when first and second moving parts move relative to each other. When the engaging member is in the coupled position, the first and second moving parts are coupled for movement together. One embodiment of the invention is a child safety door handle rotating on a spindle. Other embodiments include water faucets, stove or burner controls, or any other rotatable or movable parts.