FABRIC SPRING SHACKLES-A NEW IDEA.
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LIKE MANY other important 'parts of the chassis, spring shackles have never, since the first motor vehicle was designed, attracted the attention of designers, chiefly, no doubt, because they fulfil their function fairly well, are small, and, therefore, not easily noticeable.
Nevertheless, it remains that these components are apt to wear considerably after a few thousand miles, when rattle will develop. In any case, if squeaks and friction are to be avoided, constant lubrication is necessary, and the wear of the pins calls for occasional replacement thereof.
All the inherent disadvantages of the ordinary spring shackle are absent in the new Belflex fabric shackles, in which rubber fabric, not unlike that used in the construction of Hardy universal joints, takes the place of the two-hinged side plates normally used. In actual practice, two slabs (if they may be so described) of fabric are firmly bolted between two specially shaped clips. One of these is rigidly secured to the dunda-iron and the other to the spring. When the longest leaf of the spring lengthens or shortens as it flexes, the fabric bends to and fro, but, owing to its great rigidity across its section, does not allow of any twisting. Incidentally, the construction of the spring is Much simplified, for, as with ordinary half-elliptic springing, iustead of an eye being necessary for the spring bolt at each extremity, one end is left flat and drilled with two holes, whilst the other end is bent up at right ',angles and punched through with two more holes. The rear end of the spring is bolted to the top clip of the fabric shackle, whilst the forward end is bolted to the pivot shackle, which is of a different type. This last consists of two discs fastened
together with two clips, the clips themselves being at right angles, and the lower one being bolted to the spring leaf, whilst the upper is attached to a pressed bracket secured to the frame. This shackle simply rocks to and fro, according to the amount of.fiexure in the main leaf in the spring. It has one other important function, however, and that is to allow for a slight twisting action produced, say, by one wheel, and not the other, going over an obstacle.
Special curved lips on the rear shackles allow for a considerable degree of bending both in normal action and on the
rebound. In the latter case the bail faired-off;lips ainchithe two thicknesses of fahric;beiween them, preventing excessive buckling or bending of the fabric.
It is quite evident, therefore, that these shackles will work absolutely without attention for thousands of miles, after which, if they show any symptoms of tearing, they can be rapidly detached and new fabric plates subetituted' at a very low cost indeed. The main point., however, is that ..quite'14 points requiring lubrication' ,are eliminated it one swoop, whilst ii is quitei,impossibit or rattle or wear to develop.
A point of interest to designers is that not only are fabric spring shackles produced at a very low cost indeed, but...the simpler attachment of the springs reduces their cost also.
The sole manufacturing rights in this country are held by the licensees, H. M. Hobson,.Ltd. 29, Vauxhall Bridge Road, Lonclon,'S.W.1, who willibe•glad to get into touch with manufacturers interested in the device. Incidentally, •::-besietee spring shackles, the Belflex Corporation, who manufacture these in America, also make a fabric torque arm mounting and a vibration-absorbing engine moenting of the same type.