A surgical knife safety device having a handle, a blade connected to the handle, and a guard carried by the handle for sliding movement between a retracted position in which the blade is exposed for use, and an extended position for covering the sharp cutting edge of the blade. In the retracted position, an enlarged guard radius is provided at the distal end of the handle to allow improved handle control and blade orientation. The enlarged guard radius is positioned to allow the user to firmly grip a large distal handle portion which is preferably molded as a single piece with the blade holder, preventing unwanted blade or handle movement due to guard mechanism tolerances. A spring, such as leaf spring or a cantilever beam, and a pair of detents or slots are provided to fix the guard in the extended or retracted position and to provide resistance during movement between the two positions. Additionally, a pushback prevention mechanism, a user operable lock and a drop-force operable lock are provided to prevent accidental retraction of the guard from the fully extended and guarded position.一種手術刀安全裝置(10或100)包括:一把柄(20或120);一刀片(40或140),其被連接至該把柄;及一護件(30或130),其被該把柄所承載,以便可滑動在一可露出該刀片以供使用之退回位置與一可覆蓋住該刀片之銳利切刃的伸出位置之間。在該退回位置時,一擴大護件(30或130)之弧部被形成於該把柄(20或120)的遠端處以供改善對把柄之控制及刀片方位。該擴大之護件弧部被適當地定位,以便使用者可穩固地握持住一較大的遠端把柄部分,而該較大的遠端把柄部分較佳地係與刀片座(26或126)整合模製成為一單件,以避免由於防護機構之公差導致不必要之刀片或把柄移動。一例如葉片彈簧或懸臂樑(52或152)之彈簧以及一對掣部(54、56)或槽孔(154、156)被設置用以將該護件(30或130)固定在該伸出或退回位置上,並可在該兩位置間運動之期間提供阻抗力。此外,一防止後推機構、一使用者可操作鎖、及一落差力可操作鎖被設置用以防止該護件意外地從已完全伸出且受防護之位置處退回。
