Patent ID: 8307775

Claim:
An impact detector comprising: a weight having a circular periphery; a case in which the weight is contained, an interior of which defines a transition path through which the weight moves when the case receives an impact of a predetermined magnitude in a first direction; a planar elastic member disposed on a first side of the case, extending in the case with a first end portion oriented in a direction in which the weight moves when the case receives the impact in the first direction, the planar elastic member including, a folded portion disposed on a second end portion of the planar elastic member opposite to the first end portion of the planar elastic member, a first arm bent and extending from a first end portion of the folded portion, including an end portion holding the weight at an initial position in the transition path, the first arm deforming to release the weight when the case receives the impact of the predetermined magnitude in the first direction, and a second arm extending from a second end portion of the folded portion opposite the first end portion from which the first arm extends; and a fixing member to fix the planar elastic member to the case, the fixing member including, a sandwiching portion to sandwich the folded portion of the planar elastic member from both sides, and a contact portion to prevent the planar elastic member from moving in the direction in which the weight moves by contacting the first arm and the second arm of the planar elastic member.