Patent ID: 7984655
Filing Date: 2011-07-26
Classification: E05F,E05Y,H03K

Abstract:
1. An entrapment prevention device for an opening/closing mechanism including a capacitive sensor arranged on at least one of a movable body, which opens or closes a space when an actuator is driven, and a receiving position, at which the movable body is received at a fully closed position, wherein the entrapment prevention device detects a foreign object between the movable body and the receiving position with the capacitive sensor during a closing movement and avoids entrapment of the foreign object between the movable body and the receiving position, the entrapment prevention device comprising: an actuator drive means for driving the actuator to perform an opening/closing movement with the movable body; a capacitance calculation means for receiving a detection signal from the capacitive sensor and calculating a present capacitance; a memory for storing the capacitance calculated by the capacitance calculation means; a comparison circuit for comparing a most recent capacitance calculated by the capacitance calculation means with a previous capacitance stored in the memory; a determination means for determining whether a foreign object is located between the movable body and the receiving position based on the comparison of the comparison means; and an actuator drive control means, connected to the determination means, for outputting a drive control signal to the actuator drive means to stop the movable body or perform an opening movement of the movable body by the actuator when the determination means determines that a foreign object is located between the movable body and the receiving position, and wherein the capacitive sensor comprises a plurality of paired sheet or film electrodes disposed proximate to an outer perimeter of the one of the movable body and the receiving position.