Abstract: A swimming pool cover assembly is adapted to be operated by hand by a single person, for extending a cover sheet over a swimming pool or for retracting the cover. The cover sheet is wound upon a drum at one end of the pool, while a rope is wound upon a spool located at one end of the drum. A hand crank or electric motor is used either to drivingly rotate the spool to take up the rope, or to drivingly rotate the drum to take up the cover. The rope is positioned in a tensioned loop configuration with its remote end being connected to the forward end of the cover sheet, and is supported on pulleys removably secured to the pool decking. The hand crank or motor drives either the spool or the drum through a gear mechanism, being automatically switched from one to the other depending upon the direction of rotation of the hand crank. Side fasteners secured along the side edges and free end of the cover sheet are removably attached to anchors on the pool decking when the cover is in its extended position.

Abstract: Disclosed herein is an improved door strike noteworthy in its ability to resist forced entry when disposed upon a door. The structure includes a member adapted to be inserted in the doorjamb and its associated studs having a cylindrical tang for deep insertion therein, a body portion having a hollowed rectanguloid configuration with a tapered curvilinear top surface attached to the tang, and on the side opposite the tang connected to the body portion is a cylindrical disk portion hving a semi-circular step upper portion remote from the tang with a groove and a lip to allow registry with the mating jimmey proof door piece which has an upstanding projection fashioned to fit in the lip and groove of the security device.

Abstract: The present invention is directed to a lock detachably engaged in a hole in the frame of a sliding window or door with an element on the lock engaging against the window or door to prevent the window or door from being slid from its closed position toward an open position. The lock includes a double lead thread for fast action. An arm on the lock for engagement with the window can be positioned in either of two vertically spaced reduced diameter portions on the lock shaft.

Abstract: An ultrasonic pressure test method and apparatus that utilizes a reflectoscope, and an oscilloscope and an ultrasonic crystal and wherein the length of time that it takes for an echo to be returned is measured to provide a method and means for measuring and using the ultrasonic readings to determine whether the contents or pressure of a bottle, container or other member is proper or of the desired or safe quantity.