Common lifting protocol

All lifting and instrument changes should be done with a minimum of two people. Three people are helpful in some instances. Crane operator should turn off distracting music or other noise, and attempt to move control pendant as close to lifting job as is reasonable. The man at the load should be giving clear directions to the crane operator in a loud voice preferably using the appropriate universal hand signals simultaneously. Crane operator should not move load unless directed to by second person. Crane operator should never move crane boom over dish unless he is standing on the fourth floor to assure adequate clearance from edge of dish.

Removing relay optics mount at the cassegrain opening

Check sidecab and alidade for free drive to horizon. Drive to 87 ZA. Press stop button at cass area. Enable crane, raise boom to approx 20 degrees using indicator and chart on side of boom. Move crane control pendant to third floor, then drop hook to third floor area and mount hook scale. Add lifting rig to bottom of scale hook. Bring hook w/scale over load (relay optics) and adjust boom angle and power extension (length) till hook is centered over load. Attach lifting rig and slowly winch up till 680 lb shows on the scale. Release the two left and one right horizontal braces on relay optics. Remove lower mounting bolts. After lower mounting bolts are removed one person should climb to a safe location above relay optics to remove remaining six mounting bolts. A second person should steady load by shoving the tertiary end of mount toward cass opening. When last mounting bolt is removed there may be some slight movement as hard connection to telescope is lost. Steady load and lift high enough for stepper motors (for rotators) to clear cass mount bracing. About six to eight inches should be enough. Tie tag line to relay optics along right side somewhere close to third mirror. Winch up and rotate load up to third floor then lower to appropriate dolly.

Installing FTS

While at 87 ZA. With crane load hook still centered over cass mount rotate to third floor area, and center FTS under the hook. Install appropriate lifting rig to FTS and lift away from dolly. Install tag line to FTS at right rear lifting shackle to steady load and hoist high enough to clear safety rail on third floor. Rotate toward telescope and lower to alidade area. Man at load should steer load gently into mount area telling crane operator height adjustments and avoiding unnecessary contact with ZA screw. Install six mounting screws to main mount. Lower crane hook till load is released, then remove lifting rig. Install at least two of the bolts into the side brace to the right of the translation stage. Stow crane.

Installing 850 Rx

Set dish ZA @ 54 degrees. Enable crane and adjust boom to clear edge of dish by a minimum of 6 inches. Hook will not reach center of 850 Rx mount, but boom should be extended to max length. Rotate (left) back to third floor and center 850 Rx under hook. Install lifting rig with spreader bar and four leg shackles to four top corners of Rx. Shut off A/c power and disconnect extension cord. Disconnect network line, and hand control. Release base clamps on dolly and lift 850 to clear third floor safety rail. Maneuver fridge flex lines from behind chain hoist rail and swing load to telescope. Second man should also handle flex lines to steady load and keep free of interference. Lower Rx to relay optics stopping approx one inch above rotator plate. Swing right till wire crane rope is close to telescope backup structure. At this point the Rx will be 4 to 6 inches shy of the center of the left rotator. The second man should gently push load toward center while telling crane operator to winch down slowly. Once Rx base is inside counterbore of left rotator install aluminum tapered drift into the closest threaded bolthole in the Rx base and use to align Rx with boltholes in rotator. Winch down till relay optics has the load then install bottom mounting screws. Remove the lifting rig from the Rx and stow the crane.

Allen Guyer
2002 April

cso/safety/lifting.txt · Last modified: 2011-01-31 03:20 by sradford
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