SAWING MACHINERY, or SAW MILLs, is the name given to all kinds of machines used for cutting into pieces solid bodies, such as wood, stone, &c.
Saw-mills seem to have been erected so early as 1420 in the island of Madeira. At Breslau, a saw-mill was erected in 1427; and they were afterwards rapidly introduced into different parts of Europe.
A saw-mill, driven by wind, was erected at Leith about the middle of last century; and in 1767 or 1768. when a saw-mill was erected at Limehouse, it was de molished by the mob.
In giving an account of sawing machinery, we shall first describe the common saw-mill, which has been long in use. This machine is represented in Fig. 1. Plate CCCCLXXXII. No. 11. where BB is a bucket wheel about 18 feet in diameter, and having about 40 buckets. This wheel is fixed on the axle AA, in which there is also placed a wheel CC, having 96 teeth. This wheel drives a pillion, marked 2, with 22 teeth, which pinion is fixed on an iron axle, having a coupling box at each end, that turns round the cranks I), D. The vertical pole E has its lower end put on the crank, while its upper cod moves on an iron bolt at F, the lower end of the frame G 0. These frames, which contain the saws, arc thus made to move up and down by the motion of the crank. The pinion, marked 2, may give motion to two, three, or more cranks, and may thus drive as many saws with their frames. A ratchet wheel, No. 3. is fixed, as shown in the figure. Its angular teeth are laid hold of by the end K of the iron hook 'Hi, the other cud of which moves on a bolt in the lever IIH. The end of this lever moves on a bolt at I, and the other rests on a notch in the frame GO, so that it rises and falls with the frame. When HH is raised by the frame GO, the catch K pulls the wheel round towards it, and the catch Z falls into the teeth, so as to prevent the wheel from going back wards. Upon the axle of the wheel 3 is fixed a pinion 4, which works on the toothed rack of the frame TT, which carries the wood to be sawed. As the ratchet wheel, No. 3. therefore, turns round, it carries the
frame T,T, which carrying the wood advances on its rollers S,S, along the fixed frame UU, so as to come up against the saws as they arc moved up and down by the crank DD. The ordinary apparatus for raising the sluice and letting on the water, is shown at VV; but a self-regulating one, such as that described in our article Hynnoommutes, is used in all great establish ments. By pulling the rope at the longer end of the lever M, the pinion 2 is connected with the wheel.CC, which drives it, and by pulling the rope R, they are separated from one another. In order to -roll the frame TT backwards when it is empty, the pinion 5, with 24 teeth, and driven by the wheel CC, has upon its axle a sheave, over which is put the rope PP, which goes over the sheave 0, and turns it round. Upon the axle of the sheave 6, is fixed the pinion 7, which acts on an iron rack upon the frame TT, and drives it backward. The pinion 5 is connected with the wheel CC, by pulling the rope at the lower end of the lever N; and they are separated from each other by pulling the rope 0. In order to drag the logs of wood in at the door Y, there is fixed upon the axle 9 a wheel 8, having ratchet teeth on its rim, into which the catch 10 enters; and as this catch is raised by the lever at the upper end of the frame GG, it pushes round the wheel 8, which is prevented from moving backwards by the catch No. 11. falling into its teeth. The rope 9 Y is, therefore, coiled round the axis 9, and thus drags the logs in upon the frame TT. The catches 10, 11 are thrown out of play when the logs are laid upon the frame.
Vel'y great improvements have been made on saw ing machinery by that celebrated engineer, Mr. Bru nel. In our article on BLOCK MACHINERY, we have already given a description of several of the sawing engines, which form part of the machinery for manu facturing blocks, and we shall now confine ourselves to an account of the most important of his improve ments.