Claspknife

:"The "clasp knife phenomenon" also refers to a particular aspect of hypertonia"A claspknife or lock-knife is a folding knife, strictly speaking one equipped with some means of holding the blade in the open position when in use, so that it cannot close accidentally on the user's fingers. The term tends to refer to a medium-sized to large knife, and implies a locking mechanism such as a twisting ring or catch that must be released in a distinct action before the knife can be folded, as opposed to the more usual sliding spring which requires only that a sufficient force be applied to the back of the knife in order for it to fold into the handle, and for which the term penknife is normally used.

The term lockback knife also exists to make this distinction.

ee also

*Penknife
*Opinel knife
*Pocket knife