Alarm-triggering locking plate comprising a breaking plate

An alarm-triggering locking device for securing a closing area of a door or window, the door or window having a frame to which it is mounted for an opening motion relative thereto, the device comprising:

• a breaking member;
• means for attaching said breaking member to the frame;
• a first retaining member mounted to a front side of said bearing member;
• a second retaining member;
• means for mounting said second retaining member to the frame at a front separation from said first retaining member;
• and
• alarm means communicating with at least one of said breaking member and said first retaining member, wherein said breaking member ruptures in response to a first outward force to release said first retaining member for abutting against said second retaining member, thereby triggering said alarm means, wherein at least one of said second retaining member and said second retaining member mounting means first rupture in response to a second outward force which is greater than said first outward force.