TWO NEW THORNYCROFT FEATURES.
Page 25
If you've noticed an error in this article please click here to report it so we can fix it.
ONLY a few weeks ago we dealt at some length with a number of improvements which hos recently been incorporated in some of the vehicles produced by J. I. Thornycroft and Co., Ltd., but on paying another visit to the .Basingstoke works a few days ago we found further evidence of the way in which design is constantlx being improved, to Meet special requirements and to eliminate parts liable to failure.
. The first new feature is the use of Spicer universal joints for the heavier chassis, in place of the leather couplings which have been employed exclusively until now. The original reason for this change is the attitude of the bus licens• ing authority in the London area—in ether words, Scotland Yard—who abject to leather or fabric joints, on the grounds that if one gives way the propeller shaft may fling round under the effect of centrifugal force and strike the bottom of the body such an occurrence is very rare, and only happens if joints are grossly neglected, but in order to avoid even such a remote contingency the authorities Prefer, and even insist upon; the use of what, may be termed positive joints of the Hooke type. Realizing the prejudice which exists for disc joints in certain quarters, the
makers of the Thornycroft finally decided to adopt Spicer universals, not only on their bus chassis, but also on the J and Q types, and these joints certainly look very neat, and are thoroughly well protected. The second alteration applies to bus chassis only; it is the use of double brakes for the rear wheels in lieu of one brake acting direct • on the rearwheel drums and the other on the transmission. The change has been effected in a simple, manner by the employment of two independent drums in each rear wheel, the side-by-side ex
panding shoes being -operated, one by a cam provided with a hollow shank, and the other by a second earn formed with a spindle which passes through the nrst cam and shank, the protruding end carrying the operating lever.
A curious feature of the new brake shoes is that each is formed in one so that advantage is taken of the natural spring of the metal, and only one tension spring is required for each, whilst apart from this no fulcrum pin is necessary, its place being taken by a bracket to which each shoe ia bolted.