The force with which the shuttle is thrown in an ordinary power loom moving with a certain speed is always considerable, and, as a consequence of the strain exerted on the thread, it is frequently necessary to use a woof stronger than is desirable, in order that it may have sufficient resistance. On another hand, when the woof must be very fine and delicate the fabric is often advantageously woven on a hand loom. In order to facilitate the manufacture of like tissues on the power loom the celebrated Swiss manufacturer, Hanneger, has invented an apparatus in which the shuttle is not thrown, but passed from one side to the other by means of hooks, by a process analogous to weaving silk by hand. A loom built on this principle was shown at work weaving silk at the Paris Exhibition of 1878. This apparatus, represented in the annexed figure, contains some arrangements which are new and interesting. On each side of the woof in the heddle there is a carrier, B. These carriers are provided with hooks, A A', having appendages, a a', which are fitted in the shuttle, O. The latter is of peculiar construction. The upper ends of the hooks have fingers, d d', which holds the shuttle in position as long as the action of the springs, e e', continues. The distance that the shuttle has to travel includes the breadth of the heddle, the length of the shuttle, and about four inches in addition. The motion of the two carriers, which approach each other and recede simultaneously, is effected by the levers, C, D, E, and C', D', E'. The levers, E, E', are actuated by a piece, F, which receives its motion from the main shaft, H, through the intervention of a crank and a connecting rod, G, and makes a little more than a quarter revolution. The levers, E, E', are articulated in such a way that the motion transmitted by them is slackened toward the outer end and quickened toward the middle of the loom. While the carriers, B B', are receiving their alternate backward and forward motion, the shaft, I (which revolves only half as fast as the main shaft), causes a lever, F F', to swing, through the aid of a crank, J, and rod, K. Upon the two carriers, B B', are firmly attached two hooks, M M', which move with them. When the hook, M, approaches the extremity of the lever, F, the latter raises it, pushes against the spring, E, and sets free the shuttle, which, at the same moment, meets the opposite hook, a', and, being caught by it, is carried over to the other side. The same thing happens when the carrier, B', is on its return travel, and the hook, M', mounts the lever, F', which is then raised.
POWER LOOM FOR DELICATE FABRICS.
As will be seen from this description, the woof does not undergo the least strain, and may be drawn very gently from the shuttle. Neither does this latter exert any friction on the chain, since it does not move on it as in ordinary looms. In this apparatus, therefore, there may be employed for the chain very delicate threads, which, in other looms, would be injured by the shuttle passing over them. Looms constructed on this plan have for some time been in very successful use in Switzerland.
HOW VENEERING IS MADE.
The process of manufacture is very interesting. The logs are delivered in the mill yard in any suitable lengths as for ordinary lumber. A steam drag saw cuts them into such lengths as may be required by the order in hand; those being cut at the time of our visit were four feet long. After cutting, the logs are placed in a large steam box, 15 feet wide, 22 feet long, and six feet high, built separate from the main building. This box is divided into two compartments. When one is filled entirely full, the doors are closed, and the steam, supplied by the engine in the main building, is turned on. The logs remain in this box from three to four hours, when they are ready for use. This steaming not only removes the bark, but moistens and softens the entire log. From the steam box the log goes to the veneer lathe. It is here raised, grasped at each end by the lathe centers, and firmly held in position, beginning to slowly revolve. Every turn brings it in contact with the knife, which is gauged to a required thickness. As the log revolves the inequalities of its surface of course first come in contact with the keen-edged knife, and disappear in the shape of waste veneer, which is passed to the engine room to be used as fuel. Soon, however, the unevenness of the log disappears, and the now perfect veneer comes from beneath the knife in a continuous sheet, and is received and passed on to the cutting table. This continues until the log is reduced to about a seven inch core, which is useless for the purpose. The veneer as it comes rolling off the log presents all the diversity of colors and the beautiful grain and rich marking that have perhaps for centuries been growing to perfection in the silent depths of our great forests.
From the lathe, the veneer is passed to the cutting table, where it is cut to lengths and widths as desired. It is then conveyed to the second story, where it is placed in large dry rooms, air tight, except as the air reaches them through the proper channels. The veneer is here placed in crates, each piece separate and standing on edge. The hot air is then turned on. This comes from the sheet iron furnace attached to the boiler in the engine room below, and is conveyed through large pipes regulated by dampers for putting on or taking off the heat. There is also a blower attached which keeps the hot air in the dry rooms in constant motion, the air as it cools passing off through an escape pipe in the roof, while the freshly heated air takes its place from below. These rooms are also provided with a net-work of hot air pipes near the floor. The temperature is kept at about 165°, and so rapid is the drying process that in the short space of four hours the green log from the steam box is shaved, cut, dried, packed, and ready for shipment.
After leaving the dry rooms it is assorted, counted, and put up in packages of one hundred each, and tied with cords like lath, when it is ready for shipment. Bird's-eye maple veneer is much more valuable and requires more care than almost any other, and this is packed in cases instead of tied in bundles. The drying process is usually a slow one, and conducted in open sheds simply exposed to the air. Mr. Densmore's invention will revolutionize this process, and already gives his mill a most decided advantage.