Fig. 30.
[Fig. 30] shows a fore-carriage with open futchells. A A is where the stiff bar detaches to receive the shaft of the drop poles, the futchells extending to A A. The wheel-iron or stay on the outside of the futchell extends ahead 5½ inches, and also the plate on the inside of the futchells the same distance. These irons require to be a good thickness and tapering to the end. The blocks are fitted on to this space and scrolled at the end. The dimensions given for [Fig. 29] will apply to this, and it is used for the same light vehicles, only that a pair of horses are used instead of one.
Fig. 31.
[Fig. 31] shows an arrangement adapted for hard service. With this kind of wheel-plate we get a good bearing when it is turned under the body. These are made solid, with a plate on the two beds. A is the perch bolt.
CHAPTER X.
IRON AND METAL-WORK GENERALLY.—LAMPS.—PRINCIPLES OF COMBUSTION.
In addition to the foregoing, a large quantity of expensive ironwork is used in the construction of carriages; the principal cause of which expense is not the cost of the material, but the highly skilled labour which is necessary in preparing it.
In carriages suspended from C springs, the front and hind wheels are connected by a central longitudinal timber, called a perch. This has to be plated with iron in order to prevent its breaking when running over bad ground; and without this precaution there is great danger of the perch giving way, as owing to its curved form, which follows the contour of the body, it is necessary to cut across the grain, and thus weaken the timber.
These wooden perches have, to some extent, been superseded by wrought-iron perches, as previously mentioned, and these have been found to answer admirably.
In C spring carriages there are the loops, which serve to suspend the body; and these require very good workmanship, for they are curved in many opposite directions, are tapered and irregularly formed every way, yet requiring to have bearing bolts accurately adjusted, and sundry contrivances for affixing ironwork to them, and all this without a single square side for the mechanic to work from. They are samples of great mechanical skill and dexterity of hand.