Fig. 30.—Fleshing.
Machines have long been used for fleshing and scudding light goods, such as lamb-, kid-, and goat-skins, and their use for fleshing dressing hides has now become very general in the United States, and is gradually gaining ground in England. The type of machine used for these heavier leathers, varies considerably from that used for light skins, but the general principle is the same. In most cases the working tool of the machine is a cylinder with spiral blades, which are generally arranged right-handed on one half, and left handed on the other, so as not only to scrape the hide in the direction in which the cylinder works, but also to extend it sideways. Much of the efficiency of these machines depends on the exact adjustment of the pitch of the spiral, and in the Vaughn machine, which is probably most in practical use, the blades are so arranged as to form two intersecting spirals, one of steeper pitch than the other. The great difference in the machines for skins and for heavy work, consists in the means adopted to support the skin, and to carry it under the spiral blades.
Fig. 31.—Jones Fleshing Machine.
In the machine invented by the late J. Meredith Jones, the skins are supported upon an india-rubber blanket stretched over two rollers, so that the knife-cylinder works on that part of the blanket which is between them, by which great elasticity is obtained, and this machine has proved most successful in treating delicate skins. In some other forms of machine, cylinders thickly covered with rubber have been substituted for this arrangement. The Jones machine is shown in [Fig. 31]. For heavy hides the Vaughn machine is most generally used, and may be taken as the type of the rest, as the Vaughn Company certainly originated the semi-cylindrical “beam,” which forms a very important feature. Its construction will be seen from [Fig. 32].
Fig. 32.—Vaughn Fleshing Machine, front view.
It will be easily noticed that if a hide be thrown over the half-cylinder so that one half hangs outside it, and the other half falls in its hollow, and it be then rotated, the hide is first caught firmly by a spring-clamp, which has been supported above the edge of the half-cylinder by blocks attached to the frame. As the edge rises, it lifts this clamp off the blocks, and thus carries the hide under the spiral knife-cylinder. The blades of this spiral knife-cylinder are ground to a sharp rectangular edge, and partly scrape and partly cut the loose tissue of the flesh. When the half-cylinder has made a semi-revolution, it returns to its original position, and the sizes of the driving pulleys are so arranged that the cylinder travels downwards more rapidly than it rises, in order to economise time, though in both cases the hide is worked upon by the knife-spiral which is rotated at a still higher speed. The hide is of course turned on the beam-cylinder and the other half is similarly fleshed. The beam-cylinder reverses automatically, or may be reversed by hand, and its nearness to the spiral knife is also under control. It is usually covered with a thick sheet of rubber.
It is obvious that machines of this type can not only be used for fleshing, but for unhairing and scudding, by the substitution of suitable knife-cylinders, and in the case of light skins, cylinders fitted with slates are frequently employed for the latter operation. The slate for the purpose must be of a peculiarly fine and even grain, and is mostly obtained from a single quarry in Wales. The Vaughn machine is frequently used in America for fleshing hides after soaking but before they go into the limes, and much is to be said in favour of this method, as the removal of the flesh permits even and uniform action of the lime. It is, however, a distinct disadvantage to the method that the flesh appears rough-looking after tanning, and the method is most suitable in conjunction with the American system of splitting the tanned leather.