Front the difficulty of using this implement with any rapidity, the farmer employs a man who makes a busi ness of cutting straw, and travels from one farm to the next with his chaff-box at his back.
Ir H. Salmon of Woborn, Bedfordshire, has invent ed the most complete chaff machine which has yet been produced: it is represented in Plate CXXXV. Fig. I. in which AA, 1111, are two cast-iron wheels, comic( ted to gether by bolts a, a, extending. from the rim of one wheel to that of the other. The wheels are mounted on an axis C, which is supported on bearings in a proper framing, as is evident front the figure. The straw is put into a box or trough GP, and what projects beyond the end thereof is cut off by two knives b, b, attached to the in sides of the rims of the two wheels AA, BB, which are turned round by the winch handle E; or where there is a thrashing or flour-mill, an endless rope may be con ducted round the pulley or rigger ll, and thus give it motion without any trouble. The knives b, b are placed at an angle of 45 degrees to the direction of the wheel's motion. They are attached to the wheels by iron rods or levers C, moveable on a cent•e-pin, and capable of being forced forwards towards the chaff-box by springs, which are formed to adjust by screws h, and act more or less as occasion may require, so as to give the knife as much pressure against the end of the box as may be re quisite to cut the straw. The knives are prevented from coining too far forward, and occasion unnecessary fric tion, by the wedges under the staples near C ; which wedges, as the knives wear, must be drawn out so as to permit the knives to come more forward. With the pro vision before mentioned, it will be found very easy at any time to put in new knives, as the springs and levers will always adjust them to their work.
On one side of the wheel is fixed a round block of wood f, in which there are four holes and a moveable screw, acting as a crank, upon one end of the feeding arm f, g, extending nearly horizontal to the cross lever LI\L Fig. 2, to which the end of g is attached 1w a pin. The straw is brought forward by a pair of rollers in the box E, the form of which is shewn at at 7n, in Figs. 2, 4, and 5, which rollers arc turned from the outside by ratchet wheels II, on each side of the box F. The ratchet
wheels are provided with clicks, as shewn in Fig. 2, which arc actuated by means of small rods r r, Fig. 3, extending from each click, and jointed to the cross lever LI\ I, which muses upon a centre-pin c, fixed beneath in the bottom of the box 1'; by this means, the rods r, in moving either way. by actuating one or other of the clicks, turn the ratchet-wheels and rollers round a pro per quantity, to advance the straw forwards ; but this calamity can be regulated at pleasure, according to the stroke given to the cross lever 1.\i, by the feeding arm f g, and crank : The pin which attaches the end g of the feeding arm to the cross lever L, is moveable to five different holes. in L; by means of which, and the four holes in the block f, before described, for the crank-pin, twenty changes in the length of the chaff may be ob tained. By this mode of feeding. the straw is perfectly at rest, and does not press forward at the time of the cut ting ; at the same time, lifting up the feeding arm, its end is disengaged from the pin fixed at the end of the .evoss-lever, and the feeding motion is instantly thrown off, although the wheel and Ithives may continue the; motions.
Beneath the box is suspended the pressing-weight which may be made more or less powerful by shiftin. the weight on the lever from which it han. ; and i also may be thrown on either side, more or less, as orr sion may require ; which will he found useflil, in for in; the straw towards the knife, and countelbalam fug the ratchet-wheel of the upper roller. The arbor of thi lever carries two short levers, one of which is wn r, Fig. I. From these, iron rods proceed to the pivot at the ends of the upper spiked rollers, by which the straw' is always equally pressed in passing the toe spiked rollers. Great advantage is obtained in this in,: chine, from its cutting various lengths—from its testier, (luring the cut—from the knives being adjusted to by their regulating springs—from the feeding being rya (lily thrown off—and from the pressure being mot rabb to either side of the box. In consequence of the hilly, acting against the end of the box, which is ( o•,ercd steel-plate, they are constantly kept sharp.