While reading through the June 1871 issue of a journal entitled The Bureau: Devoted to the Commerce, Manufactures and General Industries of the United States, I found an article on page 508 on the 'new' Aultman & Taylor vibrating thresher, which eventually eclipsed the Pitts endless-apron style of threshing machine. On page 499 was an advertisement for the Aultman & Taylor, and on page 535 appeared an advertisement for the Pitts thresher. I thought the ads and the article would be a meaningful contribution to Steam Traction especially since the magazine is serializing a fairly complete history of the Aultman & Taylor Company.
Agricultural Machinery Threshing Machines
Excerpted -from The Bureau, June 1871, Vol 2, No. 9
In accordance with our promise in last issue, we propose to furnish our readers with some idea of the leading points in controversy between the two principles of threshing or, rather, separating grain.
The principle of threshing in all machines is so nearly alike and effective as to preclude the necessity of any further remark. The separating power is the great point of excellence to be maintained. As stated in our issue of May, we select for illustration the original Pitts and the Aultman & Taylor threshers, inviting particular attention to the mechanical construction of both; first in the order of its coming will be.
The Original Pitts
The grain is thoroughly threshed and beaten out of the heads, in its contact with the cylinder, which forces or drives it down and forwards. The bulk of the grain, estimated at 7/8 of the whole, is stopped at the cylinder by reason of the guard-slats placed there to protect the apron and the openings through the concaves.
This portion of the grain parts contact with the straw at the cylinder and falls through the open concaves and guard-slats directly into the troughs or cells of the apron. The remainder of the grain, mixed through the straw, passes up together on the apron, which is being agitated by a sharp jerking motion over the friction pullies on which it rests, until it comes in contact with the beater, 'armed with teeth' and revolving with great rapidity, which passing through the mass of straw, tears the knots and lumps to pieces and causes the greater portion of the eighth remaining therein to fall through into the cells of the apron, where it is seized hold of by the swift-revolving picker, and the particles of straw are here pulled apart most effectually, and spread out thinly on the slat-belt or rake, and whilst passing over it, is again thoroughly agitated by a vibrating arm or rocker, which motion fully dislodges the last particle of grain heretofore adhering to or mixed with the straw.
Thus we see that the process of separation is constantly taking place from the moment the sheaves are fed into the cylinder until the clean grain is delivered into the usually attending half-bushel. First, at the cylinder, when from 3/4 to 7/8 of the grain falls through the concaves and guard-slats into the apron; the remaining moiety of grain mixed through the straw, is got out of it at the beater, the picker, and in the passage over the straw-rake.
Now for the modern reformer, with all the amendments:
Vibrator, or Aultman & Taylor
The separating portion of this machine is made in the form of a long box, decked over at the top, open at the rear end and divided horizontally into three portions or sections.
The upper portion or section is stationary. Below this are two movable sections or troughs, each about 6 inches deep, fitting into each other. The middle section has a bottom formed of transverse wooden slats, with spaces between them to permit the grain to fall through.
Just above this open slat work are placed several sets of finger-bars with long projecting fingers in each. These fingers reach from one bar to the other, nearly the entire length of the separator. To one end of each finger-bar is attached an upright arm. The upper ends of these arms are connected with the stationary frame of the machine by means of leather straps, which are regulated by thumbscrews. The lower section has a tight floor to hold the grain after it is separated from the straw, and falls through the slatted floor of the upper one. It also projects under the concave, which is grated, so as to receive the threshed grain that goes through the concave and grate. It also projects partly over the sieves, and is perforated at this end, so that the grain falls through these perforations or holes, and is evenly distributed on the sieve. The lower and middle sections are both suspended on swing rods, so as to swing freely, and are made to 'vibrate' or swing backward and forward by means of the crankshaft and connecting-bars. The two sections move in opposite directions, one going forward while the other goes backward, and thus counterbalance each other, so that the machine stands still without blocking or bracing, and there is no perceptible strain on the frame.
The operation is as follows: The machine being in motion, the two sections are vibrated backward and forward and communicate an eccentric motion to the fingers, which works the straw gradually to the rear. As soon as the straw leaves the threshing cylinder, it is deflected at once to the agitating fingers by the circular deck or deflecting curve. The first rank of fingers toss the straw up with a few smart rapid blows, and it passes to the next, and so on, over the successive ranks of agitating fingers, each rank contributing to the thorough and continual shaking, until the straw passes from the machine. Meantime, whatever grain goes through the concave and grating under the threshing cylinder falls into the lower section. The grain remaining intermingled with the straw is thoroughly shaken out in its passage over the agitating fingers, and sifts through the open slat work into the lower section and is conveyed to the fan mill. The upper section is large and roomy, affording ample space for the tossing process. The 'throw' of the fingers can be INCREASED OR DIMINISHED (even while the machine is running) so as to give the straw ANY NECESSARY AMOUNT OF SHAKING, thus insuring agitation in all kinds and conditions of grain.
Thus, so far I have given in full the claims made by both parties, and know that the Aultman & Taylor has made a good solid success, and that it is no longer an experiment. Whilst so doing I also wish it to be understood that I consider that the original Pitts, as manufactured by H. Pitts' Sons, has not suffered in its well-established reputation by the progress of the Aultman & Taylor. The Pitts principle has always been right. Its application by careless and egotistical manufacturers has been the only wrong it has met with since 1837, the year of its nativity.
The coming season will find them in the lists contending for the championship in the correct principle of separating. I wish all parties a clear field and no favor.
Historian and author Robert T. Rhode is a regular contributor to Steam Traction. Contact him at : 4745 Glenway Ave., Cincinnati, OH 45238, e-mail:firstname.lastname@example.org