Yard Ramp Height Adjustment

The working height of mobile yard ramps needs to be adjustable to suit varying vehicle bed heights. The working height will also alter slightly as the vehicle is unloaded and rises on its suspension and as the forklift enters and exits. Normally a working range of  1m. to 1.7 m. is considered suitable.

Initially the yard ramp must be in its raised position and then once the vehicle is reversed into position, the ramp is lowered so that the leading lip rests on the floor of the container or truck body. The yard ramp supports are then raised further to ensure sufficient clearance that the weight of both the ramp and the load are taken by the truck under all circumstances.

There are a variety of mechanisms used to provide height adjustment and different manufacturers have varying opinions about the advantages and disadvantages of each.

The simplest and probably most reliable system uses manually adjusted landing legs. The operator quite simply winds a handle which raises or lowers the legs. As it works through a gearbox, the mechanical advantage makes this an easy task to do without much effort. This solution is normally regarded as tough, quick and simple to do and very reliable.

Other makers prefer a hydraulically operated system of height adjustment. Here the user has to operate a small lever activated hand pump which provides high pressure hydraulic fluid to the operating cylinders when required. The main drawback of hydraulically operated yard ramps is often the poor reliability of the components and the additional requirement for regular maintenance. Given the environment in which yard ramps are used, regular maintenance can often be overlooked and eventually unexpected breakdowns as a result if hydraulic system failures can occur. Whilst this may be good for the sales of spare parts by the maker, the consequences can be disastrous for users if a yard ramp suddenly becomes unavailable for use at an inconvenient time. With any hydraulic ramp it is always a wise precaution to keep a full set of system spares in stock on site, so that a competent maintenance crew can quickly get the ramp back into action.

Regulations are getting increasingly more stringent and users of hydraulically adjusted ramps will have to guard against spillage of hydraulic fluids. If it is necessary to build an anti-spillage bund wall, then this will seriously hinder manoeuvrability.

A few yard ramps have been built with motorised height adjustment, but these require the connection of either an electrical or air supply to power the driving motor. In most applications this is highly inconvenient and limits the ability to use the yard ramp as a mobile device. Normally electrical or compressed air powered height adjustment is provide only as a special option and where the user intends to use the yard ramp in a fixed location, rather than as a mobile device.

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