US2214920A

US2214920A - Grain separator

Info

Publication number: US2214920A
Application number: US268275A
Authority: US
Inventors: Claude C Calkins; Laurence A Hunt
Original assignee: Calkins Manufacturing Co
Current assignee: Calkins Manufacturing Co
Priority date: 1939-04-17
Filing date: 1939-04-17
Publication date: 1940-09-17
Anticipated expiration: 1957-09-17

Description

Sept. 17, 1940. c. c. CALKINS ET AL GRAIN SEPARATOR Filed April 17, 1939 2 Sheets-Sheet l wefzi afd/x p 7, 1940. c. c. CALKINS El AL 20 GRAIN SEPARATOR Filed April 17, 1959 2 Sheets-Sheet 2 Patented Sept. 17, 1940 UNlTED STATES hliitfitt GRAIN SEPARATOR Claude G. Calkins and Laurence A. Hunt,

Spokane, Wash, assignors to Oalkins Manufacturing 00., Spokane, Washington Wash, a corporation of Application April 1'7, 1939, Serial No. 268,275

Claims.

This invention relates to grain separators of a type disclosed in Letters Patent to Jesse Barber,

No. 2,043,978, dated June 16, 1936, and also in an application filed by us on or about the 15th day 5 of February, 1938, Serial No. 199,608, wherein the threshed grain with its chaff and the finer particles of straw are delivered from the thresher beaters onto an endless slat carrier, beneath which is a shaking screen onto and through which the grain falls, a blast of air being directed through the screen from beneath toward the tail end to drive off the fine straw and chaf! that drops from the carrier with the grain onto the screen, the cleaned grain dropping through the screen and being collected in bags or other receptacles by a screw conveyor disposed crosswise beneath the screen.

We have found by extensive experiments that the effectiveness of such a separator to recover 20 from the tailings of a thresher grain that would otherwise be lost depends very largely on the motion given to the screen and to the material on the screen. In the aforesaid Barber patent the screen frame is horizontally pivoted at its 5 front or receiving end, and its rear or discharge end is supported on a pair of rapidly revolving eccentrics so that the screen has an up and down vibrating movement that is greatest at its rear end and gradually diminishes toward its front pivoted end. In our aforesaid application, Serial No. 190,608 the screen frame is horizontally pivoted at its front or receiving end on theupper ends of a pair of underlying pivoted arms, and is given a compound up and down and fore and 35 aft or undulating movement by means of a pair of eccentrics rotating in a pair of bearing blocks attached to the undersides of the side limbs ofv the screen frame.

The main object of our present invention is to provide an improved grain separator of this general type that will effect an even greater separaration and recovery of grain from the straw and chaff and a cleaner condition of the grain than has heretofore been possible, and this we accomplish by a novel screen supporting and agitating means by which the screen is given a combined upward and rearward swing of such rapidity and force that the bulk of the fine straw and chaff is tossed upwardly and rearwardly off the top of the screen and is momentarily floated on the air blast until the return movement of the screen has been effected and the straw and chaff has resettled on the screen, whereupon the same action of the screen is repeated, so that the line straw 55 and chaff, indepi ndgntly of the action of the air (01. arc-a2) blast, is gradually shifted step by-step or in successive hops, so to speak, toward and finally discharged off the tail end of the separator. The momentary floating of the straw and chaff on' the air blast above the grain on the screen enables the air to clean the grain much more effectively and thoroughly than where the bulk of the straw and chaff is in contact with the top sur face of the screen and mixed with the grain seed during its entire travel over the screen.

An illustrative embodiment of the invention is shown in the accompanying drawings, in which- Fig. l is a top plan view of the separator.

Fig. 2 is a longitudinal vertical. section taken on the line 22 of Fig. l, with the blower casing and blower omitted.

Fig 3 is a view similar to Fig. 2, with the frame omitted, and showing the screen at the limit of its upward and rearward swing. v

Figs. 4, 5 and 6 are diagrams illustrating variations in the steepness of the swinging movements of the screen obtainable by changing the points of suspension of the suspending arms of the screen. I

Fig. '7 is a perspective View, broken off at one corner, of the screen, screen frame, and screen swinging means.

Figs. 8, 9 and 10 are crosssections taken on the correspondingly numbered lines of 2.

In the assembly views, Figs. 1 and 2, we have shown a portion of the usual housing ii of the threshing portion of the harvester-thresher or combine, with the foot board or bridge I? extending transversely of the housing for delivering material to the separator. At the front low" or portion of the housing a conventional fan blower is, indicated by dotted lines in Fig. 1, is located and serves to direct the air blast through the throat l4 toward the front end of the separator for the separation of the lighter chaff from the grain.

A separator frame comprises principally side walls I5 and a bottom wall It, a portion of which latter inclines downwardly toward the front or receiving end of the separator and merges with a conveyor trough ll containing a screw conveyor I8 for delivering the salvaged grain at one side of the machine. On the upper edges of the side Walls are inwardly extending flanges l9 (Fig. 8) which overhang and protect certain link bearings later described from the straw and chaff flowing onto the separator.

Describing now the moving parts of the separator which are housed in the separator frame, designates as an entirety an. endless conveyor rake comprising parallel sprocket chains- 2| and cross rods or slats 22, the chains 2i being guided around and supported by sprockets 23, 24 and 25 fast on

shafts

26, 27 and 28 respectively, journaled in and between the side walls l5 of the housing. Underlying the top lap of the endless conveyor rake 20 is a screen designated as an entirety by 29. The structural details of this screen are best shown in Fig. '7, wherein it will be seen that the screen frame comprises parallel side bars 30, end bars 3!, and (preferably) an intermediate longitudinal bar 32. Overlying the top of the screen frame is a reticulated screen 33 of sufiiciently wide mesh to readily pass the largest size grains that are handled by the thresher. On the upper sides of the side bars 36 are attached metal strips 34 to protect the side bars 39 from the wear of the conveyor chains 2i, as shown in Fig. 9; and the outer and bottom sides of the side bars 30 are preferably reinforced by angle bars 35, as shown in Fig. 9. At the four corners of the screen frame, the side and end members are securely bonded by rectangular strips 36, the horizontal limbs of which are alined with the wear strips 34, and attached to the side rails 35, and the vertical limbs of which are engaged by bolts 31 extending through bolt supports 38 welded to the lower horizontal limb of the angle bars 35.

Secured to the cross bar M at the delivery end of the screen frame is an angle bar 39 carrying a rod 40 on which are mounted a series of spring tines 4| that form in effect a longitudinal extension of the screen, and the free upturned ends of the tines overlie a cross bar 42 that is rigid with a fixed rounded guide 43 that overhangs the sprocket shaft 28 to guide the straw off the end of the separator without clogging the shaft bearings. These last described structural features are disclosed and claimed in our pending application, Serial No. 190,608, above referred to.

Turning now to those features of the screen support and screen swinging means wherein this invention mainly resides, on the side walls I5 at the receiving end of the separator are mounted a pair of metal straps 44 each having a central inwardly offset portion 35 (Fig. 8) containing a row of spaced holes 46, M and 48, the relative disposition of which holes is best shown in the diagrammatic views, Figs. 4, 5 and 6. A similar pair of straps M is mounted on the rear end portions of the side walls l5. Suspended from these straps by pivot pins 69 (Fig. 8) which are adapted to engage with any of the holes 46, 4'! and 48, are depending links 59 each carrying at its lower end a pin 5| engaged with a bearing block 52 attached to the angle bar 35. As shown in Figs. 2 and 3, the links at both ends of the screen are parallel to each other in all positions of the screen; and, to effect the motion of the screen by which the chair and fine straw on the screen is repeatedly tossed upwardly and rearwardly by the reciprocations of the screen, the links are, in all positions of the screen inclined downwardly toward the rear or delivery end of the separator. The practical result of this is best illustrated in the diagrammatic views, Figs. 4, 5 and 6, from which it will be seen that the upward path of movement of the screen is along the arcuate lines a, b and c. If the links are pivoted in the holes 58 (Fig. 6) the arcuate path a is of minimum height and steepness. If the links are pivoted in the holes 46 (Fig. 5) the arcuate path 0 is of maximum height and steepness A h link r pi oted n the holes i! (Fig. 4) the arcuate path I) is of intermediate height and steepness. This manner of optionally mounting the links so as to give the screen an upward swing through paths of greater or less height and steepness is to accommodate the separator to the most advantageous handling of different grains, wherein the straw and chaff may be of different specific gravities.

The screen may be swung endwise by any suitable mechanism, but we have herein illustrated one simple practical mechanism for this purpose. Journaled in and extending between the side walls 85 beneath and crosswise of the screen is a rotary shaft 53, fast on which are a pair of eccentrics 54. 55 designates each of a pair of transversely flexible arms, each conveniently made of a steel strip bent and folded on itself. One end of each arm 55 is attached at 56 to the underside of a side rail of the screen frame; and in the loop formed by the two limbs of the arm at its other end is an eccentric bearing block 5'! with which the eccentric 54 is engaged.

On one end of the shaft 28 is a sprocket 58 (Fig. 1) driven from any suitable source of power; and on the other end of shaft 28 is a sprocket 59 which, through a chain 66, drives a sprocket 6! fast on the shaft 53.

In the operation of the separator, practically all of the clean grain seed is collected in the trough ll at the forward or front end of the separator. We have also shown herein a second grain trough 62 served by a screw conveyor 63 that is located in the bottom wall l6 of the sep arator frame rearwardly of the main grain discharge conveyor IB, and this auxiliary conveyor takes care of and handles a relatively small quantity of grain and other seed that requires further separating steps for the final recovery of the grainseed, or may be used as chicken or stock feed. As the conveyor rake 20 drags the straw over the discharge end portion of the separator a considerable part of this mixed seed drops between the tines 4i and is deflected downwardly by an apron 54, from which it passes down the bottom wall I6 into the trough of the auxiliary conveyor 63. This auxiliary separator is disclosed and claimed in our copending application above noted, and forms no part of the present invention.

From the foregoing it will be seen that the screen, being suspended on two parallel pairs of links has a movement on the principle of a parallel ruler; and further that this movement in the rearward direction is an upward movement throughout, and in the reverse or return direction is a downward movement throughout. Hence, as

before stated, the fine straw and chaff on the screen is successively tossed upwardly and toward the discharge end of the separator, virtually floating on the upwardly and rearwardly directed current of air during the return movement of the screen, if the air blast is on. But even if the air blast should fail, the step-by-step advance of the straw and chaff over the screen will occur, because the return arcuate movement of the screen is faster than the vertical gravity descent of the straw and chaff onto the screen. This peculiar movement of the screen we have found to be very effective in separating the grain from the fine straw and chaff with which it is mingled, yielding a larger percentage of clean grain than is obtainable with the separators of the Barber Patent, above ide 5rd and our aforesaid pendi g application.

Changes in the details of structure and arrangement may be resorted to within the scope and coverage of the claims.

We claim: 7

1. In a grain separator of the class described, the combination of a frame including side walls, an endless conveyor rack mounted on said frame, a screen frame and screen underlying the top lap of said conveyor rack, suspending means for said screen comprising a pair of rigid links pivoted at their upper ends to said side walls and at their lower ends to the sides of said screen frame at each end portion of said screen, said links being inclined downwardly toward the tail end of the separator in all positions assumed by the screen during its swinging movement, means for imparting an endwise swinging movement to said screen, and means for directing a blast of air through said screen from beneath.

2. An embodiment of the subject-matter defined in claim 1, wherein means are provided for pivoting the upper ends of the links at any of a plurality of laterally spaced positions by which to vary the height and steepness of the upward swing of the screen.

3. An embodiment of the subject-matter .defined in claim 1, wherein a plurality of laterally spaced pivot holes are provided on the side walls of the separator frame for optional pivoting of the upper ends of the links, said holes being so located as to cause said links to effect-variations in the height and steepness of the upward swing of the screen.

4. In a grain separator of the class described, the combination of a frame including side walls, an endless conveyor rake mounted in said frame,

a screen frame and screen underlying the top lap of said conveyor rake, supporting means for said screen comprising a pair of links pivoted at one end on said side walls and at their other ends to said screen frame at each end portion of said screen, means for imparting an endwise swinging movement to said screen comprising a rotary shaft journaled in and between the side Walls of the separator frame, a transversely flexible arm attached at one end to the screen, and means on said shaft engaged with the other end of said arm for effecting reciprocating movements of said arm, and means for directing a blast of air through said screen from beneath.

5. In a grain separator of the class described, the combination of a frame including side walls, an endless conveyor rack mounted on said frame, a screen frame and screen underlying the top lap of said conveyor rack, suspending means for said screen comprising a pair of rigid links pivoted at their upper ends to said side walls and at their lower ends to the sides of said screen frame at each end portion of said screen, and means for imparting an endwise swinging movement to said screen comprising a rotary shaft journaled in.