• Home
  • Download PDF
  • Order CD-ROM
  • Order in Print
Figure 11-14.Typical ammunition handling hoists
INPROVED WEAPONS HANDLING SYSTEM (IWHS) LOWER-STAGE WEAPONS ELEVATORS

Aviation Ordinanceman 1 - Aviation theories and other practices
Page Navigation
  308    309    310    311    312  313  314    315    316    317    318  
operated. In addition, all of the elevators are rated for a 9,000-pound load capacity, and the elevator trunks have side-loading capabilities at several magazine levels. Except for minor differences, the elevators aboard the USS Eisenhower and the USS Carl Vinson are almost identical to those aboard the USS Nimitz. The foIlowing text contains a brief description of the two major classifications (lower-stage and upper-stage) of weapons elevators. Regardless of the type of installation a weapons elevator provides a safe and efficient means for you to handle weapons and weapons components among the magazines and the various assembly, staging, and arming areas within the ship. LOWER-STAGE WEAPONS ELEVATORS (5,500 POUNDS).— The 5,500-pound, lower-stage, weapons elevator (fig. 11-15) services magazines and ammunition handling areas from the 7th-deck level up to and including the 2nd-deck level. The components of the elevator include an electrically powered, multiple-drum winch, an elevator platform, an enclosed, watertight, vertical trunk with doors located at the levels and stations serviced, and a semiautomatic control system. Ramps are used to bridge the gaps in the door opening between the elevator platform and the deck. These allow you to load or unload the elevator platform by using forklift trucks or wheeled skids. Figure 11-15.—Typical 5,000-pound lower-stage, weapons elevator. Each lower-stage elevator is equipped with a broken-rope safety device, a down-speed governor device, and slack cable-sensing devices. The broken-rope safety device is mounted on the elevator platform assembly. If any one of the platform suspension ropes break, a roller-wedging mechanism automatically operates to lock the platform to the guide rails. A counterweight-type governor device for limiting speed of elevator down travel is located in the upper end of the elevator trunk. The governor is operated by a wire rope connected to a lever of the broken-rope safety device on the elevator platform. Then, the rope is passed over the governor sheave and attached to the governor spooling drum on the hoisting winch. Excessive down speed causes the governor limit switch to shutoff the power to the hoist motor and electric brake. Loss of electric power causes the brake to automatically stop the elevator. If the brake fails to stop the elevator, the governor sheave grips the governor rope, causing the broken-rope safety device to stop the elevator. A slack, cable-sensing, safety device is provided for each suspension rope and the governor rope. Located in the area between the winch drums and the overhead sheaves, these devices function by applying a spring-loaded follower roller to the wire rope. Rope slack causes a proximity switch to shutoff electrical power to the hoisting winch motor and brake, which stops the elevator. If the elevator overtravels upward beyond the maximum up stop position, an overtravel limit switch is actuated. This stops the elevator by shutting off power to the hoisting winch motor and brake. If the elevator overtravels downward beyond the hold deck loading station level, the platform is stopped by spring bumpers in the bottom of the elevator trunk. The slack-cable switches are actuated to cut off power to the hoisting winch motor and brake. An operator-attended control panel is located next to all elevator doors. All operator control panels have a display of selector switches, pushbuttons, and indicator lamps suited for the control functions required at the station served. All control panels have an emergency stop-run switch from which all operations of the elevator can be stopped. The main operator control panel and electrical power switch are located at the 2d deck-level station. An elevator can be dispatched to another level from any operator control panel. The lower-stage elevator control 11-24







Western Governors University

Privacy Statement
Press Release
Contact

© Copyright Integrated Publishing, Inc.. All Rights Reserved. Design by Strategico.