Car XxX Blog

This eccentric plot has been applied to dynamo chain adjustment for some years and the primary chain adjustment on the Lea-Francis consisted of a circular gearbox with the shell offset in relation to the mainshaft, but it has been left to Messrs. Veloce and Irving to apply such a common-sense adjust­ment to the secondary chain.
Patent No. 3 provided the real eye-opener, being none other than the employment of a stressed-skin rear frame, in which suitably formed sheet metal replaces the tubular construction usually associated with the job of sup­porting the rear wheel and accom­modating road shocks. As the photographs and drawings show, a single sheet of metal, bolted to the tubular centre frame at several points, acts as mudguard and support for the top ends of the spring plungers and base for pillion seat and saddle. The rear half of this member can be arranged to hinge, thus giving access to the rear wheel, whilst toolbox, battery carrier and other " cupboard space " can also be combined in the one pressing.

The Friction Dampers
Another particularly interesting detail consists of the built-in friction damper incorporated in each spring plunger. The male member carries two Ferodo rings standing proud of suitable supporting steel collars which are firmly attached to the plunger. These act as guide bearings. Placed between the collars are two semi­circular pieces of Ferodo, forced out­wards and into contact with the female outer sleeve by a circular clock spring, which exert a predetermined pressure. The assembly is designed to run dry ­indeed, lubricant obviously has a deleterious effect on brake lining material-and has proved entirely satis­factory and devoid of wear.

Lest that last statement be taken with a grain of salt, may I add that Irving demonstrated the test machine, which has covered over 90,000 miles without any replacement in the suspen­sion system, when I gained ocular proof that no wear has taken place over this great mileage. As Phil emphasized the fact in no uncertain terms, I had better state at this stage that the machine under discussion is, in his own words, " A lash-up intended to prove principles and not to win beauty prizes." When experimental work is completed and a production prototype is built, the appearance will probably be very different.
Lash-up or no lash-up, a road test soon proved the efficiency of the design. For purposes of comparison, the experi­mental " springer " and a standard rigid-frame model were ridden out by Phil and myself to a vile, unmade road on a housing estate, the surface of which deteriorated rapidly from uneven cobbles to cobbles with gaps and then to gaps with exposed manhole covers and other aids to aviation. I first tried the " springer " with the plungers in the forward, or most resilient, posi­tion and then had a second run with the plungers in the back notch. Even in the former case there was no " bottoming," but it was surprising to note what a difference was made to the swinging fork action by such a com­paratively small variation in the plunger angle.
On Rough Going
Having several times galloped down the stretch at some 25 m.p.h. on the spring heel, meanwhile deliberately aiming at the worst obstructions, I nearly cast myself off when I attempted the same gait on the rigid model. Hitting the edge of a particularly dreadful pothole a resounding clout-it seemed more like a pitshaft-I felt the back wheel rise to such an extent that I thought for a split second I was going over the bars. The incident must have looked funny to Phil, riding along behind me, as he said something about " What a pity the photographer is not with us." So far as I was concerned, however, it taught me a lesson; after that I did what one usually does with a rigid frame in such conditions picked out a crooked, but more com­fortable, path and took things con­siderably slower.
Manfully hiding any qualms I might have, I then mounted on the pillion device behind Phil. This, I thought, was to be the acid test of the springing, to say nothing of my courage! The result was even more impressive than when I had been in the saddle. I weigh, roughly, 15 stone, but only once did the springing " bottom " over the aforesaid pitshaft and even then I suffered no discomfort and there was no subsequent " life on the ocean wave " rocking reaction such as might have been expected.
Again it took the rigid frame to demonstrate just how efficient is the spring-heel design. Even following the excrescence-dodging path at a much reduced speed the bumping was so severe that the headlamp front fell off and I acquired a severe " headache " in reverse. The demonstration was very convincing, my only regret being that I failed to take Phil on the pillion of the rigid-frame model after the shaking he gave me!
Convinced
Some spring frames are good, others are all " spring " and others might be solid for all the benefit obtained. The Veloce type tested definitely qualifies for the first category. It has all the perfect steering qualities of the maker's excellent rigid frame, combined with first-rate comfort for rider and passenger. The lateral rigidity of the wide pivot bearing and the deep stressed-skin rear frame member must be ample for the purpose, as there was no visible trace of shake and certainly none could be felt even over rutted three-ply lanes. And let it not be over­looked that more than 90,000 miles had been covered on this machine since it was put into commission in the autumn of 1938.
Regarding ease of maintenance, the problem seems to have been solved by giving the rider no maintenance to do. The bottom bearing in each spring leg consists of a floating Oilite bronze bush, which has proved ideal for the niggling semi-rotary motion to which it is subjected. The fork pivot bearing is equipped with a simple grease nipple with suitable passages in the member leading to the bronze bushes, whilst, as has been previously stated, the Ferodo guide-cum-damper assembly runs dry.
Assembling
The assembly of the spring leg is very simple. First, the bottom Ferodo guide, with its steel collar, slips down to a shoulder formed on the inner mem­ber. Next, the semi-circular pieces of Ferodo and the little clock spring are nipped into position with a piece of string. Then the top Ferodo-and-steel collar is screwed on. Next, the spring is screwed on to the helix on the plunger and, finally, the sheath is slipped over the plunger and inside the spring. As the sheath slides over the damper segments the string is removed and then the sheath is given a half turn so that its external bayonet catch engages with the top spring coil. That's all!
To sum up, as an attempt to provide a suspension system instantly adjust­able to solo or pillion loads, allied to ease of maintenance and long life, the experiment appears to be a complete
success. I am very glad I found that patent specification. There is always a thrill in testing something new, and more particularly when the something new indicates that war-time conditions have not been allowed to cry " Halt " to post-war progress.