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Home >> Information >> Cargo Handling Gear - Lifting and Rigging

Cargo Handling Gear - Lifting and Rigging

Date: 6/13/2008 10:09:15 AM

CARGO-HANDLING GEAR

1. INTRODUCTION. Cargo-handling gear is used to secure cargo while it is being raised or lowered by the ship's gear. It also moves cargo to and from its stowage position in the ship. Proper training in the selection and use of cargo-handling gear is necessary for safe and efficient cargo operations. As terminal operations coordinator, you are responsible for training and supervising your personnel in the methods prescribed by this chapter.

2. GENERAL-PURPOSE GEAR. General-purpose gear is used with many types of cargo. This type of gear includes—

The ends of slings are usually made up into eyes, either with or without thimbles . The eyes fit on the cargo hook and attach to the drafts or loads of cargo. By these eyes, a sling is joined to another sling, a hook, or a ring, either directly or by using a shackle. Thimbles in the eyes strengthen the sling by protecting it from sharp bends around pins, hooks, shackles, links,rings, and similar objects.

 
 

    a. Endless Slings. Splicing the ends of a piece of wire or fiber rope makes an endless sling. It is simple to handle and can be used in several different ways to lift loads. The endless sling is most commonly used as a choker hitch. When the endless sling is used as a choker, personnel pass it around the draft or cargo forming a loop on top of the draft. The other end is passed through this loop, pulled tight and attached to the cargo hook. To balance the load, personnel spread apart the two parts of the sling on the bottom of the draft.

      (1) The endless sling is also used with chime or running hooks. It may be used as a basket sling or a vertical sling .

      (2) Personnel should not use endless slings to lift bagged cargo such as sugar, flour, and cement. These types of items require canvas slings.

 
 

    b. Single Slings. A single sling is made of fiber or wire rope. Each end of the single sling is made up with an eye, a hook, a ring, or a thimble, depending on the intended use of the sling. A single sling may be used as a vertical sling, a basket sling, or a choker sling with a choker hitch .Single slings made of fiber rope are used for light loads and for cargo that might be damaged by wire slings. Slings made of wire rope have a variety of uses. They are made in lengths ranging from 5 to 150 feet or longer for special cargo. Running hook wire rope slings may be used to hoist drafts of lumber, dunnage, iron pipe, building steel, strong boxes, and large cases .Each running hook sling is made with 18-inch eyes at each end. Personnel use the sling by wrapping it around the draft, attaching one eye to the sliding hook, and putting the other eye on the cargo hook.

             c. Combination Slings. Combination slings combine two or four single slings to form a bridle, basket, or choker sling. Combination slings can lift virtually any type of load. When several slings are passed under large crates or boxes to form a basket sling, cargo handlers should use spreader bars to prevent crushing.

    d. Chain Slings. These slings are used mainly for handling steel rails, pipes, beams, and angles. Chain slings are used in bridles or single legs .Cargo handlers should use dunnage between the chain and the draft to prevent slipping. If necessary, dunnage also should be used between individual pieces in the draft. When hoisting cargo of this type, cargo handlers should make a round turn (complete) with the chain around the draft. Cargo handlers also use chain choker slings ,Chain choker slings are used to handle such cargo as steel rails, pipes, and steel beams. Cargo handlers place dunnage in such a way to give the sling a better grip. The sling's links are wrought iron; this iron will stretch before it breaks, thus giving warning. Other types of iron may simply crystallize and snap. Watch for warning signs such as stretching links, fracturing, and stretching hooks.

 

 

e. Canvas Slings. A canvas sling is a rope sling with a section of canvas sewn between the ropes . The main type of canvas sling in use is the dirt sling. In commercial practice, canvas slings similar to dirt slings are used for handling cargo such as nitrate.

 

 
 

3. SPECIAL-PURPOSE GEAR. Special-purpose gear is made for use with certain types of cargo. It includes—

  • Cargo nets.
  • Pie plates.
  • Pallets.
  • Bridles.
  • Plate-handling clamps.

    a. Cargo Nets. Cargo nets are usually made of manila rope, but nets of wire rope are used for special cargoes. The standard Army cargo net is 14 by 14 feet with a 7 7/8-inch square mesh. The square meshes are made of 2 1/2-inch circumference manila rope. The line around the circumference of the net is made of 3-inch circumference manila rope. Cargo nets are used to handle loose packages that are not all the same size. The package must be strong enough to withstand pressure. When making up a draft in a cargo net, cargo handlers should stack the cargo so that the crushing effect of the net is kept to a minimum.

     

    b. Pie Plates. The crushing effect of a cargo net may be reduced by using a round "pie plate" . Pie plates are constructed of two dunnage layers. They vary from 54 to 72 inches in diameter. Personnel place the pie plate in the center of the net and tack the cargo so that all the weight is on the pie plate. If pie plates or pallets are not available, cargo handlers use cargo boards to reduce the crushing pressure of the cargo net. Cargo boards are constructed of two layers of dunnage nailed together to make a solid board measuring 4 by 6 feet. The cargo board is placed in the center of the net and is used in the same way as a pie plate.

    c. Pallets. The four basic types of pallets used in military cargo handling are the stevedore, general-purpose, sled, and warehouse pallets.

     

      (1) A stevedore pallet, which is reversible, is used to handle loose cargo at water terminals . The standard stevedore pallet is 4 feet wide, 6 feet long and 8 inches high. The stringers are made of 3- or 4- by 4-inch lumber. The deck boards are made of lumber 2 inches thick. The outside boards may be random widths. The outside stringers are set in 4 to 6 inches from the ends so that a pallet bridle may be inserted. The inside stringers are arranged to permit easy entrance of forks for movement by forklift trucks.

      (2) A general-purpose pallet is a four-way-entry wood pallet, 48 inches long, 40 inches wide, and approximately 5 1/2 inches high . This pallet is used mainly for the shipment of palletized cargo and often accompanies the cargo from shipper to consignee.

      (3) The sled pallet is a heavy timbered platform with runners .Supplies and equipment are normally banded to the pallet.

 

 

(4) A warehouse pallet is used to handle cargo in warehouses. It is much lighter than the stevedore pallet. The most common size of warehouse pallet is 48 by 48 inches, but a 40- by 48-inch size is also made. The warehouse pallet can be the open end type that is moved by a forklift or hoisted by a pallet bridle, or the closed end type that is moved by forklift only.

 

      (5) When items of cargo are palletized, the tiers are laid so that one tier ties together with another to give stability to the unitized load and to keep the cargo from falling off the pallet while it is being moved. Cargo handlers can obtain greater use of the pallet area by building the load in a definite pattern whenever possible.

     

    d. Spreaders. A spreader  is any device used to keep the side pressure of the sling legs away from the load being hoisted. Some commonly used spreaders include—

       

    • Vehicle spreaders with wheel nets.
    • Heavy-lift spreaders.
    • Barrel sling spreaders.
    • Pallet bridle spreaders.

      (1) A vehicle spreader is made of lengths of hardwood, pipe, or steel beams. It permits a straight pull on the sling and wheel nets. This keeps pressure away from the sides of the vehicle to be hoisted.

        (a) Wheel nets are used for hoisting sedans and other light vehicles .The wheel nets included in the cargo set vehicle are 8 by 3 feet, with 6-inch mesh. Manila rope that is 3 inches in circumference is used in the net with the exception of the frame which uses 3 3/4-inch manila rope.

         

         

        (b) When using the sling and wheel net, the winch operator lowers the cargo hook until the wheel nets are on the ground. The nets are spread out in this position so there is enough clearance between the top of the cargo net and the bottom of the vehicle spreader to allow the vehicle to enter.

        (c) The vehicle is pushed until its wheels are in the net. Cargo handlers may also use other types of slings to load vehicles. For example, a four-legged bridle can be used if the vehicle has been fitted with lifting eyes.

      (2) Heavy-lift spreaders are made of steel beams because stronger material is required to keep greater pressure away from the side of the heavy lift .

      (3) Barrel sling spreaders may be triangular, straight, or square .They are usually made of plate steel with holes for the shackles which hold the chime hooks. Cargo handlers may hoist a number of drums at one time with the use of the barrel sling spreader.

 

 

      (4) Pallet bridle spreaders keep pressure away from the sides of the draft .The straight types are made of steel or hardwood.

    e. Bridles. Bridles are lifting devices designed to hoist special types of cargo. They may be used in conjunction with spreaders. A list of the most common types of bridles follows.

 
 

      (1) Pallet bridles are used for quick, efficient handling of palletized cargo . Cargo handlers should insert the lifting bars at the bottom of the nets into the ends of the pallet to use the bridle. Then they should spread the sling nets around the cargo as far as they will reach and slip the eyes over the cargo hook. The bars at the top serve as spreaders.

 
 

      (2) Beam bridles are used to remove hatch beams from their sockets Cargo handlers should place the hooks on opposite sides of the beam in the lightening holes or rings as provided. The beam will then ride level and straight up and down. Tag lines are attached to the bridles for control and safety.

 
 

      (3) Vehicle bridles are used for efficient handling of various types of vehicles. The size of the bridle depends on the size of the vehicle to be hoisted. Cargo handlers should use vehicle spreaders with wheel nets for passenger vehicles. Heavy-lift spreaders are used for trucks.

      (4) Heavy-duty bridles are used to reduce side pressure on heavy lifts. Bridles use a combination of wire rope, shackles, hooks, rings, or chain. Cargo handlers should know the safe working load of this type of gear when using these bridles. Table 4-1 gives the recommended minimum size of shackles, chain, hooks, and rings to be used with various sizes of wire rope.

     

    f. Plate-Handling Clamps. Plate-handling clamps are designed exclusively for handling steel plates. They are used to lift the plates into position to be properly slung with wire rope slings. They are safe for use only when the steel plate is not lifted to a great height. They are not used to hoist steel plates into or out of a hold. If the plates hit the coaming or the side of the hatch, it will release the tension and the clamps will drop the plates. The two most common types used in military cargo handling have serrated jaws and a 5-ton capacity .

Table 1. Recommended minimum sizes of gear to be used with
various sizes of
wire rope


Improved plow-steel
6 x 19 wire rope
(hemp center)
New
wrought-
iron chain
(diameter
of stock in
inches)
Round-pin or
screw-pin shackle
(diameter of pin in
inches)

Drop-forged steel hooks
(diameter in inches)

Steel rings and links
(diameter of stock in inches)
Diameter
(inches)
Safe load
(pounds)
Screw pin
Round pin
Eye
Throat
Circle
Oblong
Triangle

1/2

 

1/16

5/8

3/4

7/8

1

1 1/8

1 1/4

1 3/8

1 1/2

4,300

 

5,400

6,600

9,400

12,800

16,000

21,200

26,000

31,400

37,000

1/2

 

9/16

5/8

3/4

7/8

1

1 1/8

1 1/4

1 3/8

1 1/2

3/4

 

3/4

7/8

1

1 1/8

1 1/4

1 1/2

1 5/8

1 3/4

2

5/8

 

3/4

3/4

7/8

1

1 1/8

1 3/8

1 1/2

1 5/8

2

1 1/4

 

1 3/8

1 1/2

1 3/4

2 3/8

2 3/4

3 1/8

3 1/2

3 1/2

4

1 3/8

 

1 1/2

1 3/4

2

2 1/2

3

3 3/8

4

4

4 1/2

1

 

1 1/4

1 1/4

1 1/2

1 3/4

2

2 1/4

2 1/4

2 1/2

2 3/4

9/16

 

5/8

3/4

1

1 1/8

1 1/4

1 3/8

1 1/2

1 3/4

1 3/4

3/4

 

7/8

7/8

1

1 1/4

1 1/2

1 3/4

1 3/4

   

2 1/4

      (1) The single lever grip clamp is used for lifting plates in a horizontal position. It has a tapered jaw opening, a toothed clamping arm, and an oval ring. It picks up the plate resting in a horizontal plane and keeps it horizontal while it is being lifted.

      (2) The double-toothed cam grip clamp is chain operated with a sling link for lifting steel plates in a vertical position. It can lift only one plate at a time. It picks up the plate resting in a horizontal plane and turns the plate over until it hangs vertically.

4. CARGO-HANDLING AIDS. Cargo-handling aids are used to help handle cargo. These include items such as wedge point bars (pinchbars), rollers, and tag lines.

    a. Wedge Point Bars. Wedge point bars have a wedge-shaped working end for prying. They are used to shift heavy cases into position over short distances with a grease-like substance called skid compound. For longer distances, cargo handlers use the wedge point bar to pry the case up high enough to get rollers under it

 
 

    b. Rollers. Personnel use rollers to move cargo from the wings and ends of a hatch to the square of the hatch. There are several types of rollers usually available.

      (1) Pallet-type truck dollies or pallet dollies consist of a steel frame and eight bar rollers. Cargo handlers may land pallets of cargo on truck dollies in the square of the hatch. The dollies are then pulled into the wings where the cargo is to be stowed. Cargo handlers can place empty pallets on the dollies in the wings. When loaded with cargo, the dollies are pulled into the square of the hatch to be placed in position for hoisting the cargo.

      (2) Single rollers are round bars of wood, steel, or steel pipe. The rollers included in the general hatch cargo set are made of hardwood and are 3 3/4 inches in diameter and 4 feet long. Single rollers are used to move heavy cargo in a hold.

      (3) Gravity conveyors are normally made in 10-foot sections. They may be either wheel or roller type. Cargo handlers may set up roller conveyors in the hold to move small boxes or other suitable items of cargo from the square of the hatch into or out of the wings.

    c. Tag Lines. Tag lines are long lengths of light line made fast to long items of cargo and heavy lifts for the purpose of controlling the swing of the draft as it is being hoisted or lowered.

5. CARE OF CARGO-HANDLING GEAR. The following simple rules will help prolong the life of cargo-handling gear. Cargo handlers should—

  • Apply a light coat of oil to the wire rope slings periodically. A lubricated sling will wear five times longer than a dry sling.
  • Clean cargo-handling gear regularly.
  • Ensure manila rope slings are dry before storing to prevent mildew.
  • Keep gear not in use in the gearbox or locker to prevent damage.
  • Know the safe working load of all gear (TM 5-725).
  • Not exceed the safe working load of any part of the rigging or of the cargo-handling gear at any time.
  • Never overload a sling and never apply loads suddenly.

The article is under the globalsecurity.org CHAPTER 4,It uses CARGO-HANDLING GEAR.

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