Self-locking cutting tool for plastic pipes

A locking mechanism for a cutting tool for plastic pipes. The tool includes two elongated members pivotally connected to each other in a scissors-like manner. Each elongated member has a handle portion and a jaw portion with one jaw portion including a knife blade and the other an anvil. In the preferred embodiments, the jaws of the cutting tool are spring-biased apart toward an open position. The locking mechanism for the tool includes a bail member on one handle and a C-shaped catch member on the other. In operation, the bail member can be pivoted to an extended position to contact and automatically slide along the opposite handle into a locking position with the catch member as the handles are squeezed together.