Abstract: In an apparatus for automatic floor arrival at the time of service interruption in an A. C. elevator which is operated by an A. C. variable-voltage and variable-frequency control; when a slip frequency value during acceleration is at least a predetermined value, a burden raising mode is decided to switch running directions. Thus, in case of performing a rescue operation at the time of the service interruption, a load torque can be simply and reliably detected from the slip frequency value, and the elevator can be operated in a burden lowering direction.Another construction is such that slip frequency values during acceleration are integrated, and when the slip frequency integration value is at least a predetermined value, a burden raising mode is decided to switch the running directions.

Abstract: A solar collector comprising a heat collecting panel for receiving the sunlight, a cover glass arranged above the panel, and a sunlight-pervious diaphragm disposed between the panel and cover glass to form a closed space between itself and the cover glass, the diaphragm being adapted to expand and contract to vary the volume of the closed space, whereby the pressure in the closed space is kept substantially equal to the atmospheric pressure. With this arrangement, since the collector does not permit the entry of humid ambient air into the closed space, no condensates will be produced on the inner surface of the cover glass. Further, if the diaphragm is adapted to sag and contact the panel due to its expansion at the time of abnormal heating, heat dissipation from the panel is accelerated. Thus damage to the panel due to overheating can be prevented.

Abstract: An emergency apparatus for elevator which converts a DC power into an AC power by an inverter device in an emergency state to feed the AC power to an AC traction motor and an AC motor for door-opening and closing which have different rated voltages so as to drive a cage of the elevator and to open and close a door of the cage comprises selectively feeding a power through said inverter device to either of said traction motor or said motor for door-opening and closing, in an emergency state.

Abstract: A method for making a selective absorption film for solar energy which comprises immersing aluminum or its alloy in water which contains at least two members selected from phosphate ions, fluoride ions and triethanolamine, and optionally ions of a metal selected from copper, iron, cobalt, silver and a mixture thereof thereby forming a chemical conversion film which shows a great absorptivity and a small emissivity.

Abstract: An automatic landing apparatus in service interruption comprises; an electromagnetic brake which is released to release a main motor for driving a cage; an auxiliary motor which is equipped together with the main motor to drive the cage; an emergency power source which has a power for releasing the electromagnetic brake and driving the auxiliary motor; a brake releasing circuit which maintains the releasing of the electromagnetic brake by the emergency power source when the service interruption of the normal power source is caused during the driving of the cage; and a restarting circuit which drives the auxiliary motor when the cage is not stopped at the door openable zone when the case is moved under releasing the electromagnetic brake whereby the case is moved by the actuation of the restarting circuit.