Laminaire Suspension Does Well on Test
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VARIOUS advantages offered by the V Laminaire system of progressive suspension were emphasized in a series of demonstrations staged last week by William E. Cary, Ltd., Manchester. On a mile-long circuit of old cobbled road which in places was in exceedingly bad condition, commercial vehicles fitted with this system and one equipped with con-. Ventional suspension were tested.
The main feature of the Laminaire system, as previously described in The Commercial Motor, is that the free rear end of the laminated main springs is supported not by a slide shoe but by a flexible subspring mounted in a spring shoe. By the progressive springing design, vibration is drastically reduced when the vehicle is unladen.
The demonstrations showed how closely the wheels adhered to the road so that no "hopping" took place. The obvious torque reactions with either braking or accelerating were substantially less than on a vehicle with traditional springing.
The system has special advantages for operators carrying loads that may suffer from harsh riding or vibration.
In the Laminaire system the cantilever support spring is fully e-xtended in the unladen position—there is main spring deflection to only a minor degree. When the load is increased the top of the main spring slides along beneath the support arm, so shortening the effective length • of the springs and stiffening the suspension. Control of rebound is by means of a rubber' roller in the support arm.
Conversion of existing vehicles is now being undertaken and it has been noticed that frequently 'the weight of material used in the new system is less than that which it replaces. Normally the support shoe is secured by the use of the existing bolt hole. The fitting of the system as original equipment is said to be under consideration by certain manufacturers.
In numerous cases it should be possible to eliminate the use of shock absorbers, so lowering the overall cost as compared with the ordinary spring design. Although relatively new to this country, the Laminaire design has received extensive testing on the Continent. Among the vehicles fitted with it is a '70-strong fleet carrying precision equipment for the Royal Air Force.
In this country the system is being used as original equipment for Bode.n trailers and is optional equipment for York trailers. Designs are available for all types of prime mover and trailer.