FEATURE | MANUAL CHAINS
making fine adjustments to the height of the ROV when it is safely on deck. William Hackett offers its C4 Hand Chain Block C4-CHCB-3866, which in the high- capacity 50 ton version has 20 chain falls. It is not easy to imagine who would want
to raise a 50 ton weight by hand, unless you were an early man building the pyramids or Stonehenge; but there is a demand. “We have them available off the shelf,”
says Josh Burgess, director of Operations, William Hackett, “and they do sell.” Who buys them? “Mainly the energy industries” he says. “There are places where an electricity or hydraulic supply is not easy to install. The underside of an oil rig might be an example. But these are heavy beasts in themselves – they weigh upwards of a ton, so installing them is not to be taken lightly. “There are 20 falls of chain in our 50t
manual chain hoist, meaning there are 10 sheaves that the load chain gets pulled around. This mechanical advantage essentially suggests that it should take the same effort to operate a 50t hoist as it does a 5t hoist. This is not 100% accurate though,” - factors such as increased friction come into play - “and I have been advised that the effort required to operate a 50t hoist is approximately 500N.” More than one operator pulling on the
chain would seem essential. Nothing comes for free, however.
The downside of such high mechanical advantage is that the speed of your lifting is very much reduced – by the same ratio as the mechanical advantage, as Archimedes worked out around the year 250 BC. Raising a 50t load by hand by even
a metre would be a very slow business indeed – which accounts for the lift height of just three metres of the Yale version we mentioned above. These very-high capacities of chain hoists are, let’s face it, not common. Most applications where 50-ton loads need moving, even occasionally, would find a powered solution more efficient. If the load is of the order of 250kg to a
few tons, and if portability for use in remote sites is important, then the manual chain hoist, and its close relation the lever hoist, come into their own. So down mine excavations, or up on
overhead wires, an engineer might well want to carry his hoist with him on his belt or in a toolbox, attach it to some suitable support at his worksite, and then use it to lift a component for repair or manoeuvre it into position. The phrase ‘pocket winch’ for the ultra-lightweight and small lifting aid
William Hackett’s 30t hoist on its 75t dynamic test rig
has not until now been coined, but perhaps it should be. Thus, Yale has its Mini 360, which fits the brief exactly.
It is a compact design, the smallest of its hand chain hoists, and can fit in any toolbox. For lightness, the housing is of aluminium. The low weight promotes, they say, countless possible applications, such as assembly work in industry, car repair shops, crafts and so on. All the internal parts are protected, so the device is fit for use outdoors or in rough environments. It comes in capacities of 250kg and 500kg. The load pressure brake complies with
all technical regulations and therefore holds the load in any position. The hand chain guide has a special
the operator to pull from any angle. As well as convenience it means that he can stand clear of the load and the danger zone,
even in confined and tight spaces. The device is an all-rounder, able to be used for horizontal pulling as well as vertical lifting. Standard equipment includes forged lifting and load hooks made from age-resistant high-alloy tempered steel, which for safety gradually open when overloaded rather than breaking. The hooks can be rotated safety catches. Tiger too has a Mini range, available in
both chain block and lever hoist variants; the lever hoist makes its intended applications, for on-site repair and maintenance work, crystal clear by being supplied with a belt bag, so that it can be carried hands-free round the operator’s waist. Kito is also in that niche. Its CX010 hand chain block is designed to be easy to carry, easy to handle, and to fit in tight spaces – and to be extremely light
www.hoistmagazine.com | June 2024 | 29
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69
