(See Figure 1) Most people would be very hesitant to carry a straight razor in a pocket unless it was also enclosed within a case or sleeve.Ī common design for providing a spring-loaded bias to both the closed and fully open position utilizes a bar spring, which applies pressure, or a spring load, against the base of the blade near the pivot point. Without some means of providing a bias or lock to the closed position, the knife could swivel open, or at least partially open, unexpectedly or unintended.Īn old-fashioned “Straight Razor” is another example of a folding knife-like device with no bias or other such mechanism to hold it in either the closed, or for that matter, the open position. In the typical folding knife, the blade swings or pivots in an arc of approximately 180° from the closed position (within the handle) to the open position. Many of the tasks for which a folding knife is employed involve holding some material or holding something in place or steady while the cut is made. Another design objective is that the knife will be convenient to employ, meaning that it can be opened easily. The basic design objective of a folding knife is something that will tend to remain closed unless the user desires or intends to expose the blade and that the blade will remain open until the user desires to fold or close the knife.
AKTI Approved Knife Definitions | Protocol for Measuring Blade Length