ROAD AND WORKSHOP by Handyman
Page 42
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Use of Chains in Transport
THE remark that no one in the haulage business ever bought new chain for lashing, lifting or hauling, was once very true. From some unknown source most drivers managed to procure enough chain to serve their turn, Nowadays, however, the wise operator will purchase the correct material for the job, see that it is well cared for, and periodically have it examined and tested. All too often in the past any old length of chain would be picked up and used to lash steel structures or machinery loads—with little thought to its age, condition or capacity until some link failed and a load was spilled on the highway.
It is still true that whereas the crane loading a vehicle at the works must have tested and registered slings, ropes, and so on, there is still no one other than the operator to worry over the chain used when the load is on the move.
What, therefore, should the transport man know about chains? They fall into two groups: (I) tough fibrous iron of even, malleable quality which permits safe welding; and (2) weldless steel chain, found mainly in short lengths and particularly suitable for slings. This chain is rolled and cut out of solid steel bar and there is no joint or weld to fail. Steel, however, is not quite as reliable as high quality iron when links have to be welded. But size for size, the weldIess rolled steel link is just twice as strong as the welded iron one. Naturally, it is a more expensive item.
However, our main concern in haulage will be with the normal welded iron chain. All lashing or lifting chain should be periodically inspected for flattened or cracked links, and any such links should be cut out. All chain links should be round in section,. as any link either flattened, kinked or twisted can take an as unfair overload. Chain, in normal use, should be annealed at least once a year.
For those who may be interested in tackling this work, this is not too difficult or involved. A muffled furnace is required—this is important, as the item being treated must be kept clear of cold air. A temperature of 650° C. minimum is required and this will produce a dull cherry red—but it is wise to use a pyrometer rather than rely on eyesight alone. On reaching a temperature just clear of 650°C., and maintaining this for a few minutes to ensure a full soak, a slow cool-down is required in the muffled furnace. If the chain must be withdrawn from the furnace, bury it at once in fine ash. The chain, once it is cold, should be brushed clean and fully examined for faults which can now be seen clearly. Before use the chain should be tested. There are testing stations in most industrial areas. As a rule the staff are mobile and can come out and test on site, issuing a certificate for items tested satisfactorily.
Many operators are now more and more inclined to hand over the whole job to the testing establishments. This is recommended, as the whole duty can be well cared for, with reminders sent out when equipment is falling due for test. However, for those operators not making frequent use of chain, there are certain safety precautions and factors that should be made known to all drivers and others who may need chain to lift or secure loads. A chain is gauged by the diameter of its links. It is necessary, therefore, to know the breaking strain of any of the normal chain used in general haulage.
These are as follows: a diameter link will break at a load of I ton; a Vn.
link at 1 ton 16 cwt.; a 1.5g-in. link at 2 tons 16 cwt.; a fin. link at 4 tons; a link at 5 tons 12 cwt.; a Fin, link at 7 tons 4 cwt.; a 4-in, link at 11 tons 4 cwt.; a i-in. link at 16 tons; a 4-in. link at 22 tons; and a I-in, link at 28 tons 8 csvt.
As stated, these weights indicate the point at which each link will fail. Note should be made in a pocket book cr diary that the safe working load is onefourth of each of.the weights given above —also that the data refers only to the welded iron chain.
Tottenham Winner
THIS week's prizewinner is Mr. D. V. Brown, of.Tottenharn, London, N.17. He says that when removing the gearbox on an old-type Dennis Pax the biggest job is to remove the clutch operating form. This, he points out, is necessary before the gearbox can be drawn back.
Mr. Brown states that if the two pins on which the fork pivots are drilled and tapped it is possible to use a sleeve as a distance piece and a set screw to act as a puller, Comments Handyman: I am not aware of this problem—but the idea makes sense.
--MONEY FOR YO U ?—
Have you an idea that is worth passing on to other readers ? It must relate to maintenance practice. If a panel, on which Handyman sits, considers your idea worth publishing you will receive 3 gas. when it is printed. All entries should be addressed to The Editor, whose decision will be final. Every entry must be accompanied by a signed statement that the idea is not copyright, patented or somebody else's idea. Rough drawings will be adequate. It is up to you, We have the money. Do you have any ideas ?