Compact yet powerful hydraulics are helping reduce damage to cars when they are being loaded on to and unloaded from recovery vehicles, to date a constant worry for breakdown operators.
Recovery vehicle builder the Roger Dyson Group’s revolutionary new Hydraloader SLA recovery vehicle, which is proving an immediate success with breakdown operators, has a super-low approach sliding back recovery platform which has been developed with hydraulics supplier Hy-Pro (Hydraulic Projects Ltd) of Dawlish in Devon.
In a conventional slide back transporter the carrying platform tilts and slides backwards until the front of the platform is at the rear of the vehicle and the rear contacts the ground. This gives a loading angle of about 12deg, steep enough to make loading cars with low spoilers.
On the SLA, the loading platform slides along a tilting subframe to the rear of the chassis and allows the bed to automatically continue tilting until the front of the bed is very close to the ground. This gives a loading angle of 4.5deg, making the loading of even the most difficult car easy.
In order to achieve this geometry the design team had to develop an incredibly compact drive mechanism. Hydraulics are the only way to achieve the power density required for a recovery vehicle and this is particularly true of the Hydraloader. So instead of the conventional cylinders, Hy-Pro developed a system that uses a compact hydraulic motor and probably the most compact valve available on the market.
Hy-pro’s designers studied the performance requirements and realised that they could be fully satisfied with their established V5-60 sectional spool valve. This was originally developed for agricultural applications, but its ability to mix manual and solenoid control soon proved useful in other fields, while its low profile format meant it could go where many valves of comparable performance simply could not fit.
With a flow rate of 60-litres/minute and pressure capacity up to 250bar, the V5-60 was comfortably within the main performance specifications for the Hydraloader. Its wide operating range of -20degC to 65degC means it can be fittedto virtually any vehicle, even those destined for export to extreme climates.
To overcome the harshness associated with direct acting solenoids, the Hy-Pro V5-60 uses an internal oil pilot to operate the main spool. This incorporates a damping orifice in the pilot line, which is carefully designed to give simultaneously fingertip control and excellent load holding.
The V5-60 as supplied for the Hydraloader SLA has a multiple valve chest, so that it activates every axis, including the hydraulic winch motor and the tilting cylinder. This makes for a simple, compact, reliable and easily maintained power system and Dyson’s customers are reporting that it is so easy to use that less training is required.
For more information, please call:
Alan Wilson, Hydraulic Projects Ltd, Dawlish Business Park, Exeter Road, Dawlish,
Devon EX7 0NH
Tel 01626 863634 Fax 01626 866283
Bob Dobson, BDL Matrix Marketing, High Bank, River, Petworth GU28 9AX
Tel 01798 861677 Fax 01798 861677