Mobile column lifts do not come cheap, but with a little prior knowledge, you can make a good investment.
Are the lifts manufactured by a reputable company with a long history of sales and service within the UK market? Will the supplier be able to provide a comprehensive after sales service backed up with genuine spares availability for the life of the lifts? It has been known for lift suppliers and distributors to swap and change products they offer if they can find a similar product that offers a better margin on the sale. Will you be left with a lift that seemed a good deal at the time, but that in the future you can't get any spare parts for?
Remember that mobile column lifts don't spread the load of the vehicle as evenly as a fixed 4-post ramp will. You must consider the load distribution and the axle weights of the vehicles you wish to lift, to ensure you buy the right capacity column, it is possible to overload an electro-mechanical lift (screw shaft & nut) if the thermal overload unit is set too high, resulting in premature wear to the load unit. This will not happen with and electro-hydraulic lift as once any over load is detected, the pressure relief valve will simply open, allowing the oil system to return directly back to the reservoir, leaving the lifting carriage static.
A higher lifting height is recommended when working on low floor vehicles like buses. If your premises have restricted headroom and you're concerned about putting a vehicle through the roof, then you should consider a model such as the Stertil-Koni electro-hydraulic 8.2 tonne lift that has a programmable maximum height setting.
Modern electro-hydraulic lifts are sometimes three times faster over the lifting/lowering process than their electro-mechanical counterparts. This of course, results in considerable time, labour and power saving over an annual period.
The individual columns are connected to each other via cables, which carry the power and signals to make the sets work. These often get damaged and can be costly to replace. Points to check: whether there is a plug on each end of the cable (easier to swap over and no electrician is required to hard-wire them back in): that the cables are "drive-operable" so can be driven over without sustaining damage (that is, steel-armoured); and that they are long enough to reach between the axles on your vehicles without being suspended in mid air, which would create a safety hazard.
Does every column come with a separate control box allowing the lifts to be operated from each lift? Does the set of lifts come complete with a remote control hand unit with means that a single operative can safely use them? Can the lifts be set up to operate as a pair across an axle (ideal for changing springs, for example) and as a single wheels and hubs)? Is there a slow-lowering facility? This is more important on the fast-lifting electro-hydraulic lifts, as it is difficult to inch the lift up and down, for example when trying to align up a transmission. Does the lift come complete with a pallet jacking system to aid manoeuvrability, or does it have cost saving lever method, which results in a lower set-up time? Do the control boxes have a self-diagnostic facility allowing the operator to quickly identify any faults?
It is important to look at the sorts of vehicles that you may be lifting in 5-10 years time and makes sure that the lifting capacity and feature of the mobiles you buy are suitable for the job. Will super-single tyres become more common in the UK? If so, then certain mobile lifts will not be practical to lift the vehicles, as the fork length will not cover the required minimum of two-thirds of the tread width. Will your future vehicles have more axles to spread over a greater load? Buy from a manufacturer that offers the facility of adding more columns to your existing set - some manufacturers can only offer a maximum of a three-axle lift (six columns) whereas others offer the facility to add up to 24 columns.
The newer generation of electro-hydraulic lifts are an increasingly popular choice for those garages replacing older, electro-mechanical lifts. The main reasons are due to the low-maintenance characteristics and reduced running costs associated with them, in comparison with a screw shaft-load nut design. A lift that utilises a screw shaft and load nut/safety nut operating system has to be constantly greased to avoid premature wear of the lifting nuts and eventually the nut will have to be replaced at some stage. Limit switches operating at the top and bottom of the lift normally restrict the travel of the carriage. The gap between the load nut and the safety nut is monitored by another limit switch and sometimes there are more limit switches monitoring the tilt of the carriage and ensuring that the lift is fully lowered onto its base before the vehicle can be safely lifted. Each column may have up to five limit switches; all of them could malfunction at some stage. In contrast: Stertil-Koni electro-hydraulic mobile columns, for example, have none.
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