Last month, Denis Hogan from LEEA explained how hand chain blocks are a well-established and widely used member of the lifting equipment family. But whilst they are often the first to spring to mind when considering a manual lifting machine, to identify the best solution for a particular application it is important to remember that a number of alternatives are available.

Right solution

These include the lever hoist, the hand winch, and the suspended winch (also known as a pole hoist), which is effectively a hand winch mounted at the end of a tubular pole at the other end of which is a sheave and hook. The rope from the winch passes through the tube and over the sheave to the hook. The whole machine is suspended from a point above the sheave.

Selecting the right solution invariably starts with a clear understanding of what the lifting machine has to achieve. Obviously it has to lift and lower a certain amount of weight, but how far, how frequently and how accurately? And if it has to travel, these same three questions need to be addressed again. Finally, where can the machine be controlled or operated from?

The range of lifting capacity for hand chain blocks, lever hoists, hand winches and suspended winches varies considerably, which may ultimately limit choice. However, provided the application falls within the available range, the final decision can be based on performance. In this respect, the main advantage of hand operated equipment is that the speed can be as low as the operator needs. It is therefore very suitable for precision assembly or installation work where fine control is essential.

Minimum load

In this, the second part of his paper, he explains that the brake in many hand operated lifting machines requires a minimum load to operate satisfactorily and it is advisable to avoid lifting a load of less than 10% of the working load limit.

If the lifting machine is used in conjunction with a slewing jib, runway, mobile gantry or crane bridge, then it is likely that a travel motion is required. A travelling trolley will be employed and there are three basic options: push, geared and power.

Push travel is the simplest. As the name implies, manual force is used to push – but on what? Often the operator pushes the load which, being suspended, swings away until the lifting machine makes sufficient angle to the track to overcome friction.

At this point, the trolley suddenly jerks forward. It is not very precise and the higher the track the worse the effect. If the operator cannot get behind the load to push, it is tempting to stand in front and pull.

This is potentially hazardous as the jerking motion can cause the load to swing into the operator. This sort of push travel is therefore best left to applications where the track is not too high, there is room for the operator to push without being trapped and precise positioning is not required.

A useful variation of push travel, which resolves some of these problems, is to fit a handlebar onto the trolley. This ensures that the operator can safely push or pull the trolley directly.

A geared travel trolley is moved by means of a hand chain, which drives through geared runners on one side of the trolley. It provides very good control and ease of movement even if the track is high. It has some limitations, particularly when used on a runway. Because the hand chain hangs to one side, its weight, together with the effort from the operator, tends to tip the trolley

Load condition

Under light load or no load condition it would tip, and could become derailed unless restrained. This restraint is provided by an anti-tip roller fitted to the opposite side plate and engaging with the underside of the track flange.

If the track has joints with plates under the flange, the anti-tip roller will foul on them. There are other ways of joining the track but the buyer should be aware that considerable expense may be incurred if modifications are necessary to avoid this problem.

Power travel trolleys are similar to geared travel trolleys, except that the drive is from a motor instead of a hand chain. Although they represent another option for the hand lifting machine buyer, in practice they are more usually employed in conjunction with power operated hoists