--- 鎌 is defined as a “sickle” or “scythe” which is a an instrument with a “curved” or “hooked” edge for cutting grass or crops.

--- There are many websites featuring “hook-bolt locks”
http://www.freepatentsonline.com/5516162.html
A hook-bolt lock assembly is improved in strength by hook-bolt plates (5, 6) and can be locked without inserting a key into a lock unit (22) when the assembly is locked, so as to be improved in operability. In the assembly: a movable plate (2) is biased by a spring (3) toward its projecting direction; the hook-bolt plates (5, 6) are pivoted to a casing (1); oblique cam surfaces (16, 17) of front-end hooks (9, 10), which abut on socket

--- I think that just plain “hook bolt deadlock” would be safer to use because there is more than one type of” hook bolt deadlock.”

--- In the below 2 websites you can see two different types of “hook bolt deadlocks”
1) a 5 lever hook bolt deadlock and
2) a mortice hook bolt deadlock

http://www.ironmongerydirect.co.uk/Products/Locks_Latches_an...

Chubb 3M50 5 Lever Hook Bolt Deadlock 70mm Case 43mm Backset Satin Gold


http://www.alibaba.com/product-free/800009392/Chubb_3C16_Mor...

Chubb 3C16 Mortice Hook bolt Deadlock

--- This website features a “hook bolt deadlock” with an illustration:
http://www.jmlock.com/adamsrite-hookbolt-latch-lock.aspx

--- Here is an alternative spelling with "hook" and "bolt" joined together:
http://www.qualitydoor.com/Adams-Rite-MS1950-050-Maximum-Sec...
Adams Rite MS1950-050 Maximum Security Hookbolt Deadlock (stainless steel)