(under the class definition) Device comprising a means to sense a condition or change of condition, and means responsive to the sensing means to effect a control on a closure.
SEE OR SEARCH THIS CLASS, SUBCLASS:
43, for means acting continuously to control the rate of motion of a revolving closure.
262, for an actuator, moved by the passage of a closure user to or through a closure opening.
263+, for an operator actuated by the weight of a closure user.
322, for a safety catch, operable upon breakage of a closure support to prevent falling of the closure. SEE OR SEARCH CLASS
105, Railway Rolling Stock,
349, for railway car closures automatically actuated upon the occurrence of an emergency condition, such as the overturning of the car.
