Abstract: An elevator system without a machine room is disclosed. In this elevator system without a machine room according to the present invention, a built-in winding apparatus is installed in the interior of a hoistway for moving an elevator car. In addition, the elevator system without a machine room according to the present invention is characterized in that a movement stroke of a counterweight is shorter than a movement stroke of an elevator car, and a reinforcing installation member is installed across an upper portion of a pair of counterweight guide rails which corresponds to an upper counterweight moving distance, and a pair of counterweight guide rails are integral with the reinforcing installation member, and the built-in winding apparatus is installed on the reinforcing installation member in such a manner that the elevator car is moved by a driving force transferred by a motor roping unit.

Abstract: An improved elevator door system for reducing vibration and noise in opening/closing a car door and a hatch door and allowing fast operation by releasing a landing door lock device before the car door moves. The elevator door system includes a hatch door; a car door; a motor for providing rotating force to open and close the hatch door and the car door; power transmitting means; a rack for possibly moving horizontally by the power transmitting means; a pinion engaged with the rack for rotating by horizontal movement of the rack; clutch connected to the pinion for transmitting or cutting off power toward the hatch door; and door lock engaged with the clutch, the door lock positioned in a lock release state in which the hatch door is movable when the clutch transmits power, while positioned in a lock state for fixing position of the hatch door when the clutch cuts off power.

Abstract: A method for analyzing the strength of a structure and an apparatus using the same which are capable of more simply and accurately computing the stress of each element of the structure by selectively grouping the elements of the structure, which receive a lot stress, and analyzing the stresses of the grouped elements with respect to the entire structures. The method includes the steps of a first step for grouping a concerned element of an object structure and computing a strength of the concerned element, a second step for setting a unit load value and computing a stress of the concerned element, a third step for changing a stress value corresponding to the unit load value into a related function with respect to the entire elements, a fourth step for computing a stress based on an actual load value based on the related function and actual load value, and a fifth step for analyzing a strength of a corresponding structure based on the stress based on the actual load value.