Elevator Troubleshooting & Repair. David Herres. Читать онлайн. Newlib. NEWLIB.NET

Автор: David Herres
Издательство: Ingram
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Жанр произведения: Физика
Год издания: 0
isbn: 9780831195281
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sills, hoistway doors, door tracks, and hangers are permitted to project inside the hoistway enclosure.

      ■ Where a car leveling device is provided and the hoistway edge of the sill is either flush with or projects into the hoistway, the guard is to have a straight vertical face extending below the sill not less than the leveling zone plus three inches.

      ■ Where the sill projects inward from the hoistway enclosure, the bottom of the guard is to be also beveled at an angle of not less than 60 degrees nor more than 75 degrees from the horizontal or the guard is to be extended from the hoistway edge of the landing sill to the top of the door hanger pocket of the next entrance below.

      ■ Where no car leveling device is provided and the sill projects inward from the general line of the hoistway, the guard is to be either beveled at an angle of not less than 60 degrees nor more than 75 degrees from the horizontal, or it is permitted to have a straight vertical face extending from the hoistway edge of the landing sill to the top of the door hanger pocket of the next entrance below.

      ■ Metal guards are to be installed in the pit and/or machine room located underneath the hoistway on all open sides of the counterweight runway except that where a compensating chain(s) or rope(s) is attached to the counterweight; the guard is permitted to be omitted in the pit on the side facing the elevator car to which these chains or ropes are attached.

      ■ Where pit-mounted buffers are used, the guard is permitted to be omitted where the bottom of the counterweight resting on its compressed buffer is seven feet or more above the pit floor or above the machine or control room floor if located under the hoistway.

      ■ A permanent means of access to elevator machine rooms and machinery spaces is to be provided for authorized persons. Access doors to machine rooms and machinery spaces are to be kept closed and locked. The only means of access to a machine room is not to be through the hoistway. Permanent lighting is to be provided in all machine rooms and machinery spaces.

      ■ Means of access for authorized personnel is to be provided to all pits. A stop switch is to be provided in the pit for every elevator.

      ■ For hoistway doors, interlocks are required for passenger elevators.

      ■ Elevators that are operated from within the car are to have elevator parking devices installed at every landing that is equipped with an unlocking device.

      ASME A17 Part III covers machinery and equipment for electric elevators.

      ■ Car and counterweight buffers or bumpers are to be provided. Solid bumpers may be permitted in lieu of buffers.

      ■ On rod-type counterweights, the rod nuts are to be cotter-pinned and the tie rods are to be protected so that head weight cannot crush the tie rods on buffer engagement. The weights are to be protected so they cannot be dislodged.

      ■ Every elevator car is to have a platform consisting of a non-perforated floor attached to the platform frame supported by the car frame, and extending over the entire area within the car enclosure.

      ■ Hinged platform sills, where provided, are to have electric contacts that will prevent operation of the elevator by a normal operating device unless the hinged sill is within two inches of its fully retracted position.

      ■ The elevator is permitted to be operated by the leveling device in the leveling zone with the sill in any position.

      ■ Floating (movable) platforms that permit operation of the elevator when the car door or gate is not in the closed position are prohibited.

      ■ Cars are to be fully enclosed on all non-entrance sides and on top.

      ■ Cars are to have a car door or gate provided at each entrance equipped with a car door or gate electric contact. It is to be positively opened by a lever or other device attached to and operated by the door or gate.

      ■ For elevators installed in enclosed hoistways, cars are to be provided with a car top emergency exit with a cover hinged or otherwise attached to the car top so that the cover can be opened from the top of the car only, and opens outward. Interiors of cars are to be provided with electric light or lights. No less than two lamps are to be provided.

      ■ The car of every elevator suspended by wire ropes is to be provided with a safety capable of stopping and sustaining the car with rated load. When the safety is operated by a governor, the safety is to be capable of stopping and sustaining the car with rated load from governor tripping speed. Counterweight safeties are to be provided and are to be capable of stopping and sustaining the counterweight.

      ■ Safeties are to be applied mechanically. Electrical, hydraulic, or pneumatic devices are not to be used to apply the safeties nor to hold the safeties in the retracted position. Safeties that depend upon traction for application are prohibited. When car safeties are applied, no decrease in tension in the governor rope nor motion of the car in the down direction is permitted to release the safeties, but the safeties are permitted to be released by the motion of the car in the up direction.

      ■ Rail lubricants or coatings that will reduce the holding power of the safety or prevent its functioning as required are not to be used.

      ■ The car and counterweight guide rails are to extend at the top and bottom to prevent the guiding member from disengaging from the guide rails in the event that either the car or counterweight reaches its extreme limit of travel.

      ■ Sheaves and drums are to be of cast iron or steel and are to have finished grooves for ropes.

      ■ Winding drum machines are to be provided with a slack rope device having an enclosed switch of the manually reset type that will cause the electric power to be removed from the elevator driving-machine motor and brake if the hoisting ropes become slack or broken.

      ■ In indirect-drive machines, each chain or belt in a set is to be continuously monitored by a broken belt or chain device of the manually reset type, which will function to automatically interrupt power to the machine and apply the brake in the event any belt or chain in the set breaks or becomes excessively slack. If one belt or chain of a set is worn, stretched, or damaged so as to require replacement, the entire set is to be replaced. Sprockets and toothed sheaves are also to be inspected on such occasions and to be replaced if noticeably worn.

      ■ The elevator-driving machine is to be equipped with a friction brake applied by a spring or springs, or by gravity, and is to be released electrically. The brake is to be designed to have a capacity sufficient to hold the car at rest with its rated load.

      ■ Enclosed upper and lower normal stopping devices are to be provided and arranged to slow down and stop the car automatically, at or near the top and bottom terminal landings. These devices are to function independently of the operation of the normal stopping means and of the final terminal stopping device.

      ■ Manually operated rope (shipper rope) or rod-operating devices, or rope-operating devices actuated by wheels, levers, or cranks are not to be used.

      ■ Handles of lever-type operating devices of car-switch operation elevators are to be so arranged that they will return to the stop position and latch there automatically when the hand of the operator is removed.

      ■ Elevators with automatic or continuous-pressure operations are to have a continuous pressure button operating switch mounted on the top of the car for the purpose of operating the car solely from the top of the car. The device is to operate the car at a speed not exceeding 150 feet per minute.

      ■ The means for transferring the control of the elevator to the top-of-car operating device is to be on the car top and located between the car crosshead and the side of the car nearest the hoistway entrance normally used for access to the car top.

      Electrical Protective Devices, as covered in ASME A17, Part III, will be discussed in detail in Chapter 5, Troubleshooting Elevator Systems.

      Hydraulic elevators, as covered in ASME A17, Part IV, will be discussed in detail in Chapter 2, Types of Elevators.

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