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| Arms length risk |
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(from Commercial Vehicle Workshop - November 2006)
Locking arms are a vital safety feature on two-post lifts, says Stertil-Koni.
If you've got an older two-post lift in your workshop, or one without working lift arm locks, the HSE is on your tail. Last year, the HSE expressly alerted HSE staff and local authority Environmental Health Officers about the dangers of two-post lifts. In its advice note "The Risk of Vehicles Falling Off Two-Post Vehicle Lifts in Motor Vehicle Repair", the HSE identifies the greatest risk to be from arm locking systems - either because they are not fitted or because they are defective.
Arm locking systems are not legally required, but there is an industry agreed plan to ensure the fitting of them to all lifts by January 2007. BS AU 161-1b:1983 was the first British Standard to recommend carrying arms to be fitted with automatic mechanical locking systems that prevented the arms from moving inadvertently. The more recent BS EN 1493:1999 vehicle lifts, have specified arm locking systems for all two-post lifts. According to the HSE, there are a few pre-1983 lifts still around, but if they are found by inspectors after 1st January you will not be allowed to use them. If your lifts conform to these standards, they will have arm locking systems in place, but you need to check they are operating correctly.
What is the risk?
The arms on a two-post lift pivot at the column. The length can be adjusted either telescopically or through articulation. At the free end of each carrying arm there is an adjustable pick-up plate fitted with a rubber mounting pad.
The carrying arms can usually rotate when they are within approximately 100mm of the ground. Once above this height, the arms are locked at whatever angle they have been set. Locking is generally mechanical using either interlocking sliding gear elements, or a sliding boss that engages on a fine-toothed spline, or a split nut operating on threaded rods.
Van alert
The growth of higher capacity 2-post lifts (5-7 tonnes) that cater for vans and light trucks means that the pick-up arm lengths are now much longer than they used to be. This results in accentuated movement at the pick-up pad, unless a fine-toothed locking mechanism is used (as in the Stertil-Koni patented system).
Also, manufacturers recommended pick-up points are getting smaller, less accessible and further apart on the newer range of vans (for example, Mercedes Sprinter and Ford Transit), resulting in the increased possibility of unsafe lifting conditions, slippage etc, unless the correct lift is used.
Asymmetrical designs of 2-post lifts, popular for cars, are no good for these light commercial vehicles - you need a symmetrical arm layout, often not available with older lifts.
There is a particular risk of vehicles falling when the mounting pads on the carrying arms' vehicle pick-up plates are missing, badly worn or contaminated by oil or grease. All these can affect the friction between the surfaces in contact. Any other work on the vehicle, either directly (for example, undoing a bolt or removing the engine) or indirectly (for example, using a jack to lift a component back into position) could generate strong forces which, in turn, could result in slippage, rocking or other movement of the vehicle. Movement could arise during the removal of major components from a raised vehicle, as this will affect its weight distribution. |
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