An activation mechanism for a battery for an electronic ignition mechanism contains an ampoule filled with an electrolyte. The mechanism for breaking has a snap spring element to which the ampoule is attached in a freely suspended manner. The snap spring element snaps from a first shape into a second shape when a force due to acceleration is applied, thereby severing the attachment of the ampoule.

An activation mechanism for a battery for an electronic ignition mechanism contains an ampoule filled with an electrolyte. The mechanism for breaking has a snap spring element to which the ampoule is attached in a freely suspended manner. The snap spring element snaps from a first shape into a second shape when a force due to acceleration is applied, thereby severing the attachment of the ampoule.

A variable stiffness structure configured to isolate a mass from unwanted vibrations includes a negative stiffness element and an actuator operatively coupled to the negative stiffness element. The actuator is configured to be actuated to control a stiffness of the negative stiffness element. The variable stiffness structure may also include a positive stiffness element coupled to the negative stiffness element.

A concealed fire sprinkler includes a main body, an arm extending along the main body and a receiving slot formed on the arm. A bottom cover is fixed by the arm at bottom of the main body. An elastic component is received in the receiving slot. Two ends of the elastic component contact with the arm and the bottom cover. Accordingly, the conventional problems that the temperature sensing speed of concealed fire sprinklers is not capable of increasing rapidly can be solved.

A concealed fire sprinkler includes a main body, an arm extending along the main body and a receiving slot formed on the arm. A bottom cover is fixed by the arm at bottom of the main body. An elastic component is received in the receiving slot. Two ends of the elastic component contact with the arm and the bottom cover. Accordingly, the conventional problems that the temperature sensing speed of concealed fire sprinklers is not capable of increasing rapidly can be solved.