Facts about material handling:-
- It does not add to the value of the product but to the cost of the product.
- It accounts for 36% of the total production cost.
- Nearly 50 – 100 tones of material is handled or re-handled for every tone of finished product.
- A large part of the labor cost is accounted by material handling department.
- About 66.66% manufacturing cycle time is spent in handling the material.
- About 40 accidents out of 100 accidents take place due to material handling.
Tips for good erection & rigging:-
- first find out the correct weight of the load to be lifted in RIGGING AND ERECTION.
- slightly lift the load check for CG , imbalance etc.
- while lifting ensure that the load is not obstructing to any of the parts of structure.
- while using spanners, riveting hammer at height tie with a rope to a fixed structure.
- loose nuts & bolts must be kept in a box and not on the structures.The box to be properly anchored.
- Avoid sudden break or sudden release of the load . Impact load may result in breaking of the rope/chain.
- persons with B.P or epilepsy shall not be allowed to work at heights.
- barricade the area of loads lifting/ sparks falling.
- safety belt is a must at heights more than 1.8 meter in RIGGING AND ERECTION.
Construction of 6/19 wire rope:-
6=no. of strands
19( 1/6/12) I.e 12wires over 6 wires over one wire.
Type of cores:-
- Fiber core: sisal, polypropylene or nylon
- Wire core : IWRC (Independent wire rope core), SSC (steel strand core) or Armor core
Construction of 6/19 wire rope in RIGGING AND ERECTION
- Ordinary: all wires in the strand are of same diameter.
- scale: larger diameter wires out side and smaller inside. This arrangement gives more resistance to abrasion.
- Warrington: alternative large and small wires are formulated to give great flexibility, resistance to abrasion.
- Firlle: small wires filled between large outer and inner rows of large size wires.
SWL of natural ropes:-
Reduction in diameter of the rope due to core failure , abrasion etc
should not be more than
- 1.0 mm for the ropes up to—19mm dia
- 1.5mm for ropes of————22-28mm dia
- 2.0mm for ropes of ————32-38mm dia
WIRE ROPE SAFETY IN RIGGING AND ERECTION:
- Never over load.
- Minimize shock loading to the extent possible.
- Use higher capacity ropes when the exact load is not known. If there is a possibility of shock loading and if there is a hazard to personnel.
- Prevent the rope from sharp corners with padding.
- Avoid dragging the rope from under loads or over obstacles.
- Avoid dropping the rope from heights.
- If loop forms do not pull it out. Unfold it.
- The rope must be replaced if the visible broken wires are 5% or more of the total wires in a length of 10 rope diameter.
- The rope must be replaced if this wear exceeds 1/3 of the diameter of the wire.
- An approximate elongation of 150 mm per 30 M of rope in a six stranded rope and approximately 230 to 255 mm in eight stranded rope can be expected when a new steel rope is put in use, which is known as constructional stretch. Ropes having an excessive stretch beyond this should be replaced.
Precautions in use of chains:-
- chains or chain slings should never be shortened by tying knots in them.
- do not use the chains if the links are locked, stretched or without free movement.
- Do not hammer a link to straitened it or force it into the position.
- Do not drop chains from heights.
- use padding at sharp corners.
- use slings such that the angle between slings is more than 90 dig.
Type of hitches in material handling:-
- Bridle hitch
- Basket Hitch
- Choker hitch
Double basket hitch:
inclined legs SWL=SWL of single vertical hitch x H/L x4
Double choker hitch, SWL=SWL of single vertical hitch x A/B X H/L x2 when the angle is less than 45 dig.
Note:If the angle is more than 45 dig. Take A/B=3/4
Minimum number of clips
up to 19 mm—– 3
above 44mm—- 6
The bridge of the bull-dog grip to come load side and U-bolt on shorter end of the rope,don’t tight the grips too much tight or too loose.The clips shall be kept 6 dia of the rope apart.
Proper Method of Lifting a Load (Manually):-
- Place your feet firmly on ground about one foot apart .
- Keep your one leg slight in front of the other and as close to the load as possible.
- Bend your knee and hip with the back straight (“Straight” does not mean “VERTICAL”)
- Keep the load close to the body
- Grip the load firmly from opposite ends by ensuring contact between the object and the palm.
- Lift the load in such a way that your chin remains straight in line with back (this will help you to keep your spine straight and firm) and the vision is not disturbed / obstructed
- Position body so its weight is centered over the feet and lift by straightening the legs
- Put down the load again by bending hip and knee by keeping the back straight.
- One corner should be put first to remove fingers from other side.
Gas cylinders safety -10 commandments:-
- Don’t store them near wet soil or exposed to sun or heat source
- Do not use them as work supports or rollers (may be the cylinder full or empty
- Do not lubricate the cylinder valve threads or other fittings
- Cylinders must be maintained in an upright position and secured against tipping, falling or rolling. Never drop cylinders or permit them to strike each other violently.
- Protect surface of cylinder from any cuts or abrasions.
- Valve protection caps must be fully threaded in place when cylinders are not connected to user system.
- Do not carry the cylinder on your shoulder.
- Never lift cylinders by the caps.
- Never open the acetylene more than 1/2 turn, sudden opening may lead to explosion
- never keep the cylinders in battery charging room or never allow them to come in to contact with live wires.