CRANE AND HOIST

a. State 3 limit switches found on a crane and describe their purpose?

-Maximum hook height prevents hauling hook and connecting gear through the jib head sheave

-Maximum jib elevation- prevent the hauling gear overstressing the luffing wire and to prevent the load from getting too close to the crane post

-Minimum jib elevation as the jib elevation decreases the stress on the luffing wire increases, also the outreach radius increases and is more likely to strike obstruction

-Dancing roller this detects any slackness on the running gear so there are no over-riding turns on the drum

b. What is the purpose of limit by-pass switch?This is necessary from time to time and usually the minimum jib elevation limit switch when it is to be lowered down to its stowage cradle after use

c. What marking are required on the jib of the crane? The SWL and next to it the maximum corresponding jib outreach

d. Purpose of the overhauling weight (ponderball)? This is to ensure that there is no slack in the runner when there is no loading being lifted

e. Minimum amount of turns allowed on a smooth drum of a crane when involving a lifting operation? 3 turns

f. Minimum amount of turns allowed on a grooved drum of a crane when involving a lifting operation? 2 turns

g. 6 safety precaution when carrying out lifting operation?Stay out under a loaded boomKeep all motion with heavy weight slowHeavy weight should never be allowed to dropNever keep load in the air any longer than necessaryAvoid swinging the load. Attached tag lines to control the loadDo not used crane to drag loadAvoid sudden shock / strainsEnsure load is free to be liftedEnsure load is balance and will not shift when liftedOnly lift as high as required to clear from obstructionh. Describe hand signal

Hoisting the load= finger pointing up with rotating motion

Lowering the load= hand palm down with up and down motion / side to side motion

Slewing right/left= point to the right / left

Jib down/up= fist closed with thumb up/down