Document 82j7pOnQN1dkby0KRwJKk8kV5

POWER TRUCKS rear, depending on tile location of the oper ator's seat, precautions must be taken to avoid striking pedestrians, especially when these trucks are carrying long loads Red flags may be attached to tbe ends of the load, or flagmen may be stationed m con gested areas, particularly if the truck is used after dark Powered handtrucks The principal hazards in the operation of powered handtrucks include the operator's being pinned between the truck and a fixed object or allowing the truck to run up on his heels Operators should walk ahead of the truck, leading it from either side of the handle and facing the direebon of travel During forward travel, they should keep one hand on the handle Where the truck must be driven dose to a wall or other ob struction, down an incline, or onto an ele vator, tbe operator should put tbe truck m reverse and walk behind it facing the di rection of travel Robot trucks Tbe use of robot trucks requires that aisles where the truck operates be dearly marked and dear of material Employees should be forbidden to jump on or off or nde these trucks No attempt should be made to load or unload a robot truck that is m motion Pallets An understanding of what constitutes a sound pallet will be hdpful to the safety man, since an improperly designed and con structed pallet may collapse while being handled and endanger personnel. Most pallets (Fig 20-10) have two parts* the deck or surface of the pallet and the stringers separating the upper and lower decks To designate pallet size, the length of the stnnger is given first, followed by the length of the deckboards A pallet with 2- by 4-m. stringers 32 in long, running parallel to the forks, and deckboards 40 m long, running across the forks, would be referred to as a 32 by 40 pallet Three elements are involved in the safest, most durable pallets sound lumber, secure fastenings, and proper construction Lumber Unless bandied infrequently, as in long term storage, pallets are exposed m vary ing degrees to such conditions as wear and tear caused by repeated entry and stniang of forks and handtruck wheels, impact or strain exerted by dropped articles, static loads Imposed by storage and stacking, and distortion or bending by various types of handling equipment Tbe lumber must have sufficient strength for nails, bolts, and other fastenings to hold the pallet together with out breaking under stress. A good pallet should be constructed throughout with sound lumber, and be free of decay and free of knots with an average diameter greater than one-third the width of the board or stnnger There should be no knots in nailing areas, in the centers of deckboards, where the greatest bending stresses are imposed, nor along the bottom and top edges of deckboards Posts used in construction should also be free from knots Pinworm holes, mineral streaks, and stain are permissible defects in pallet parts, since they do not affect the structural strength of the wood A hardwood pallet has long life and great strength because of its density The soft wood pallet is lighter and therefore a better shipping medium The most popular hard woods for pallets (because of their strength) are red and white oak, hard maple, hickory, birch, beech, white ash, and rock elm Gumwoods, which are softer species, are much used Softwoods often used include south ern pine, Douglas fir, ponderosa pine, cot tonwood, hemlock, and spruce Softwood pallets are generally made from seasoned lumber, but the majority of hard wood pallets are made from unseasoned or partially seasoned lumber The best hard wood pallets of nailed construction have deckboards of air-dned material and string ers or blocks with a moisture content up to 40 per cent. Nailing difficulties make it economically impossible to manufacture a hardwood pallet with seasoned stringers or blocks Air-dned material should be spea- This discussion of pallets is adapted from an article entitled "XI Tips for Buyers of Wooden Pallets," by William H Sardo, Jr, front the April 1054 issue of Modem Materials Handling, used with permission of the publisher 20-13