Thrashing-Machine.-Thrashing and cleaning machine. Thrashing and separating machine. Thrashing and winnowing machine. All the above terms are applied to the same class of implement. The operation of simply thrashing is rarely resorted to, since the additional parts necessary to perform the winnowing add but very little to the cost, while increasing vastly the utility of the machine. The term cleaning, as applied to thrashing machines, is synonymous with the term winnowing. The term separating, however, is applied to such processes as separate the grain from the straw, and all such other purifying and assorting as cannot be performed by the simplest process of winnowing. Hence processes which separate the grain into divisions of equal gravity are separating processes, while those intended simply to remove matter foreign to the grain itself are termed cleaning processes. The first and simplest processes of cleaning and separating only are performed in the thrashing machine-the further cleaning, polishing, and separating processes being done by the miller. See mills
In Fig. 108 is represented a sectional view of an excellent thrashing and cleaning machine, the design of Minard Harder, of Cobleskill, New York. In this machine the grain is fed into the machine as denoted by the arrow marked 1, the thrashing operation being performed conjointly by the roller A and the concave; thence it passes to the separator C, which allows the loose grain to fall through, while the straw passes along, finding exit as denoted by the arrow 2. The grain and chaff passing through the separator fall into a trough and thence to three sieves marked respectively D, F, and F. G is a revolving fan which forces a current of air between the sieves, the grain falling through while the chaff and dust are carried away with the air-current produced by the fan. The revolving cylinder A is provided with a series of spikes arranged spirally in rows around its circumference. The concave is a bar standing parallel with the axis of the cylinder A, and contains stationary spikes, and in the passage of the straw through these spikes the thrashing is performed.. The spikes beat the grain-ears, loosening the grain therefrom. The rotary motion of the cylinder A throws the grain and straw to the separator C, and to maintain an even feed of the same to the separator the beater H is provided, consisting of a revolving shaft carrying three wings. This serves also to prevent the grain-straw from being thrown by the cylinder A too far forward upon the separator C. In the rear of the beater or feeder, and equalizer, as it may be more properly termed, is hinged a light board marked J, whose duty is to force the straw lightly down, and prevent its being thrown too far forward by the beater. The separating device is shown in Fig. 109 , in which K K K K K are perforated boards between each of which are situated the blades c. These perforated boards and the blades are operated reciprocally, the motion of the boards being in a direction opposite to that of the blades c ; the motions are slightly vertical as well as lateral, so that during the reciprocating movement the blades rise and fall through the separator-boards. When the motion of the blades is toward the arrow 2, in Fig. 108 , the blades lift, thus carrying the straw toward that end of the machine. The blades I are not level upon their upper edges, but are serrated with teeth similar to saw-teeth, the front of the teeth facing the rear of the machine so as to hold the straw on the one stroke, and allow it to pass over the sloping back of the teeth during the backward motion. In addition to this, the upper edge of the blades has a wave-like form, and the highest part of one blade is opposite laterally to the lowest part of the next one, so that they impart to the straw a combined zigzag, vertical, and horizontal movement toward the arrow marked 2 , affording ample disturbance to the straw to insure the falling of the grain therefrom. The double crank denoted by L is employed to operate the rod M', which is attached to the separator, and also the rod N attached to the trough O . The separator and the trough are suspended by links. By suitable construction, while a reciprocating movement is given to the separator in nearly an horizontal plane, the blades are made to receive, in addition to this horizontal movement, simultaneously with the separator, a vertical movement (up and down) at nearly right angles in relation to the separator. The grain after falling through the separator to the reciprocating trough O traverses by reason of the motion of the trough and its own gravity to the end P, and thence falls to the delivery-board Q. Upon the end of the board Q is a row of forks f, whose duty is to prevent foreign substances from falling in a body upon the first sieve D, which is termed the chaffing-sieve. The middle sieve E carries the operation of cleaning still further. The sieve D is coarsest, and has its square meshes of the same size for all kinds of grain, while the mesh of the middle sieve is varied in the size and shape of its mesh to suit the grain. For buckwheat and barley a square mesh, and for wheat, rye, and oats, a mesh longer than it is wide, are employed. The lower screen F has more slant than the others, in order to separate seeds and small grain. The cleaned grain falls from the sieves into the grain-spout, and the screenings into the screening-drawer at V, while the chaff and dust pass out with the air-current as shown by the arrow 3. The capacity of this machine, as determined by a test in Auburn, New York, in 1866, is 250 bundles of wheat-straw, producing 11 bushels of very clean wheat, thrashed in 40 minutes.
In Figs. 110 and 111 are represented an English thrashing-machine. Fig. 110 is a side elevation, showing the framing, stiffened around the edges, and at intervals in the length, by plates. It also shows the arrangement of the pulleys for driving the drum, shakers, fan, etc. The other view is of a longitudinal section through the centre of the machine, and shows clearly the arrangement of drum, shakers, shoes, barley-awners, and fan. The engravings explain the arrangement of the machine thoroughly, and we need not, therefore, attempt any detailed description, but confine ourselves to the special features of this machine, other than the iron framework mentioned above. The drum-spindle is of steel, and the rings placed upon it are slotted out, as shown in Fig. 111, to receive a number of iron bars, to which the beater-plates are attached, this arrangement being found preferable to introducing wood beneath the beaters. The concave at the back of the drum is entirely of wrought-iron. The shakers consist of four boxes, the straw-platforms being arranged as shown. They are actuated by two crank-shafts, one at each end, connected with the shakers by brackets. The cranks are provided with long bearings, and a collar at each end, over which the top bearing-block overlaps, to keep out the dirt. The reciprocating dressing-shoes are hung on spring rods, as shown, and are worked by a crank-shaft similar to those for the shakers. The whole of the blast employed in the machine is taken from one fan, shown in Fig. 111, one part being taken under the riddle of the main dressing-shoe, and the other thrown upward to act on the corn as it passes from the cleaner to the screen.
The elevators are entirely within the machine, and lift the grain from the reservoir. It will be rioted that the main difference between the English and American machines consists in that, in the former, revolving flails are employed instead of a spiked roller and concave. In England, however, the straw is used for thatching barns and stacks, so that it is desirable that it should leave the machine unbroken. This object is better served with the revolving flails than with the spiked rollers.
Figs. 112 to 114 represent Berdsell's improved machine for thrashing and hulling clover. The thrashing-cylinder D has four rows of wedge-shaped teeth set spirally on its surface, as shown in Fig. 112, which take the clover-stalks from the seed-board A, and carry them up as indicated by the arrow under the concave I, which is provided with three rows of teeth. As the teeth in the concave are only half as far apart as the teeth in the cylinder, the latter are so arranged as to pass alternately through the spaces between the teeth in the concave. The vibrating-board E conducts the thrashed clover on to the upper bolt B, which is made of thin boards, perforated with holes one and one-eighth inch in diameter; and in the same frame is a screen ,B', with holes three-fourths of an inch in diameter. When the screen moves toward the thrashing-cylinder, it descends and slips forward under the straw, and rises as it moves back, carrying the straw from the thrashing-cylinder, and it passes off at the end of the screen, while the bolls and seed pass through the screen on the table T. A belt of slats, b b, carries the bolls and seed off of the table
T on to the inclined feed-board P, which conducts them on to the hulling-cylinder L. The shaft of this cylinder may be provided with a pulley or gear to turn it and operate the machine, as the pulley l on this shaft is connected by belt to pulley 2 on the thrashing-cylinder. The cylinder L is covered with iron roughened like a rasp, and case-hardened. It is provided with a concave of iron, having a rasp-surface similar to that of the cylinder. L and the bolls and seed fed to the cylinder off the board P are carried up as indicated by the arrow, and over between the cylinder and concave which separates the bolls from the seed both falling to the board M'. They are then carried by the belt of slats, b b, to the screens of woven wire Q Q, to the shoe O, which screens and separates the hulls from the seed the latter pawing through the screens, while the hulls pass off at the end of the screen.
The case F' around the fan compels the blast to pass between the end of the board M and the screen, so as to paw among the seed; and the blast also passes between the screens and under the lower screen, thus mingling with the falling seed. The screens B traverse so fast that they slip forward under the straw as they descend, and, as they rise and move back, they lift the straw and carry it back. This operation being continued, the straw passes off at the rear end of the screens.
A bran-separator is illustrated in Figs. 116 to 117. Fig. 115 is a sectional view, and Fig. 117 a sectional plan, with the top parts removed, in order more plainly to show the parts represented in Fig.116 . A is the shaft; B, the cylinder; C, the inner revolving shell; and D, the outer or stationary shell. The cylinder is made by framing staves of the form and in the position represented at 1, 2, 3, etc., Fig. 117 , into corresponding cast-heads; the staves thus forming the longitudinal and working surface, and which may be covered with any kind of material that will make it rough and durable. Air is let into the cylinder at the lower end, through holes around the centre, and spaces between the staves emit it to carry the flour and other stuffs through the several qualities of wire-cloth with which the inner surface of the revolving shell is covered. The cylinder is driven by a belt and pulleys, as is represented at the bottom of Fig. 116. The inner surface of the revolving shell is covered with the above-named wire-cloth. Thus, the space between the top and the beveled dividing ring E, Fig. 116, is covered with a quality that will let through little else but pure flour, which falls, and by the dividing ring is conducted into an endless trough I, attached to the inner and sheet-iron or zinc-lined surface of the stationary shell, and by the sweepers F, attached to the revolving shell, is brought around and discharged at the Spout G. The space between the dividing rings E and H is covered with a quality that will discharge an inferior quality to the above, which falls, as above, into the endless trough J, and by the sweepers K is brought around and discharged at the spout L. The space between the dividing rings H and H is covered with a quality that will take out the fine particles of the bran, called dusting, which falls, as above, into the end-less trough N, and by the sweepers O is discharged at the spout P. The space between the dividing ring M and the bottom is covered with a quality that will separate the shorts from the bran, the shorts falling to the bottom, or into the endless trough R, and by the sweepers S is discharged at the spout T, the bran passing down the inside of the revolving shell and b the arms U of its cast-head is swept around to and discharged at the spout V. The revolving shell is driven by a combination of ear-wheels.
