striking plate 
锁舌片
门锁舌片
Striking \Strik"ing\,
a. & n. from {Strike}, v.
{Striking distance}, the distance through which an object can
be reached by striking; the distance at which a force is
effective when directed to a particular object.
{Striking plate}.
(a) The plate against which the latch of a door lock strikes
as the door is closed.
(b) A part of the centering of an arch, which is driven back
to loosen the centering in striking it.