The operation of the machine is now, in its general character, pretty obvious ; while the carriages are passing from one end of the slider to the other, by the action of the hydraulic press above explained, the wheel is put in rapid rotation, and so adjusted by means of another hy draulic press, shown in the transverse section in Fig. 6. that the gougers and planers attached to the horizontal wheel HH just catches the surface of the piece of wood e e, in its passage under it. The gouges being arranged in its rim, at different distances from the centre, and these being followed by the two planing irons in the rota tion, render the surface thus exposed to the operation beautifully plane and smooth.
Operation of the Cocks.--We have stated generally, that, by exposing the front, or back of the piston, in the hydraulic cylinder ff, Fig. I, 2, to the action of the com pressed air and water in the condensing vessel, the piston, with its rod and rack, are driven either way at pleasure ; let us now endeavour to explain the very ingenious con trivance adopted for the purpose of producing this change of action.
The cocks k, seen in Plate CCCCLXIII. Fig. 2. are shown enlarged in Figs. 3. and 4. the former being a plan, and the latter an elevation of the same. Referring to Fig. 3, a a represents a pipe called the entrance pipe, which is open to the condensing cylinder in another appartmcnt, and in which the water is constantly kept under a pressure of about 14001b. per square inch. The other pipe b b is called the waste, and is connected with a vessel open to the atmosphere, and exposed only to its pressure. The smaller circle in the cocks A and B is a sort of brass plug, having, the former one and the latter two, curving holes ef, a b, and c d. This plug (confining our remarks at pre sent to the cock B) may be turned by means of the han dle shown in Fig. 4. the other end of the same serving as an index to the workman, the upper plate having engra ved upon it, open, shut, backwards,forwards, to indicate the position of the handle in these cases. In Fig. 3. the pipe g h leads to the back of the cylinder towards h, (Fig. 2. Plate CCCCLXIII.) and the pipe c i to the front of the cylinder towards g. In the position in which the handle is supposed to be placed in the figure, the plug, or cock, is so situated, that there is an open communication be tween the entrance pipe a a, and c i, leading to the front of the cylinder g, while the pipe g h is open to the waste b b. In this case, therefore, the motion of the piston in the hydraulic cylinder is from g towards h ; the water which had previously been forced in between the piston and the end h being now returned to the waste. The piston hav ing arrived at h, the handle k (Fig. 4. Plate CCCCLXIII.) is turned, and with it the brass plug c d a b, in such a way that c takes the place of d, d the place of a, and, of course, a the place of b, and b that of c. In this new position,
therefore, the pipe g h will be open to the entrance pipe a a, and c i to the waste b b; the water, therefore, which in the former position was under compression in the hy draulic cylinder ff, between,g and the piston, is now re lieved of that pressure, and is open to the waste; and the compressed water, now entering at h, will return the piston, with its rod and rack, back again towards g; when the cock is again turned back, and the former motion repeat ed. To effect this, the handle moves through a quadrant, as is obvious; and if it be made to move through only hall a quadrant, then it is evident that the bores in the cen tre plug being excluded from any communication with either pipes, the machine will be at rest. The hydraulic cylinder, rack, pinion, and wheel, enlarged, are shown in Fig. 5.
Of the Method of Raising and Lowering the Princi pal Cutting Il1/2cel and Spindle —This is effected by means of the cock A, Figs. 3. and 4. which acts on precisely the same principle as that last descrihed, except that the cen tre plug has but one passage through it. Here the pipe m n is that which passes to the bottom of the hydraulic cylinder g h, (seen in the enlarged transverse section) Fig. 6. under the piston h, and which may be opened to the waste or entrance pipes at pleasure, by means of the han dle k, Fig. 4. as explained in the last case. In the position shown in the figure, the pipe nt n is open to the waste ; and. consequently, the piston the spindle C, and wheel HH, are down, and the cutters, when the wheel is in mo tion, will act upon the wood e. When it is necessary to raise the wheel, in order to pass the carriages and wood under it, or for any other purpose, the handle k is turned so that the hole or passage, which now connects ni 71 with the waste pipe b b, may then connect it with the entrance pipe a a ; in this latter case, the pressure passing under the piston at h raises the former, and with it the steel socket a, in which a pin projecting from the end of the spindle turns, whereby the latter and the attached wheel are also elevated at pleasure. So again, when it is requir ed to lower the wheel to any proposed quantity, according to the thickness of the wood to be planed, the passage in the cock must be again opened to the waste, till the wheel sinks to its proper place, and then the cock being shut, by turning the handle a semi-quadrant, it will be retained at that height till some new arrangement is called for. To assist the workmen in this determination, the long ruler b I in, Fig. 6. rests on the upper point of the spindle, and rises and falls with it ; and at a b is a scale of inches and parts, by which he regulates the elevation and depression of the wheel. In order that this motion may take place without throwing the wheel \V\V out of geer, a contri vance is had recourse to, which it may not be improper to explain.