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Publication numberUS1200002 A
Publication typeGrant
Publication dateOct 3, 1916
Filing dateJan 31, 1916
Priority dateJan 31, 1916
Publication numberUS 1200002 A, US 1200002A, US-A-1200002, US1200002 A, US1200002A
InventorsWalter A Mcgraw
Original AssigneeWalter A Mcgraw
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Straw-rack for threshing-machines.
US 1200002 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

w. A. McGRAW.



1,200,002. Patented Oct. 3,1916.

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Specification of Letters Patent.

Patented Oct. 3, 1916.

Application filed January 31, 1916. Serial No. 75,331.

To all whom it may concern: Y

Be it known that I, WALTER A. MCGRAW, a citizen of the United States, residing at Mount Pleasant, in the county of Titus and State of Texas, have invented'certain new and useful Improvements in Straw-Racks for Threshing-Machines, of which the following is a specification.

This invention relates to new and useful improvements in straw racks for threshing machines.

The object of the invention is to provide a rack having a transversely corrugated bottom or one having its bottom formed of substantially A-shaped sections, each successive section being higher than its predecessor; and the upwardly inclined surfaces having perforations or openings and means for retarding the progress of the straw over the rack whereby the grain is caused to drop through the openings, while the downwardly inclined surfaces have openings permitting the passage of the grain.

Another object is to provide in combination with the openings and retarding means, a plurality of transverse serrated or notched bars whichactto spread the straw so that the chaff will be more readily removed and the grain be given full opportunity to fall through the openings, said bars also acting to retain the grain on inclined surfaces:-

A further object is to provide a rack which will separate the grain, straw and chaff to the fullest extent, whereby very little if any of the grain will be lost over the end of the rack and the straw will be thinly spread over the bottom of the rack and not congested.

A still further object of the invention is to provide a rack of the character described that will be strong, durable, efficient and simple and comparatively inexpensive to construct, also one in which the several parts will not be likely to get out of working order.

Vith the above and other objects in View, the invention has relation to certain novel features of construction and operation, an example of which is described in the following specification and illustrated in the accompanying drawings, wherein:

Figure 1 is a side elevation of the improved rack, Fig. 2 is a partial plan view, and Fig. 3 is a detail in perspective of one of the sections of the bottom.

In the drawings the numeral 1 designates the frame of the rackwhich may be of the usual construction and attached to the usual oscillating means. The invention resides pr marily in thebottom of the rack which is formed of sheet metal and composed of a plurality of substantially A-shaped sections 2 extending transversely thereof, each successive section having its ridge at a higher elevation than its predecessor. The sections each have an upwardly inclined surface or side 3 and a downwardly inclined surface or side 4. At the discharge end of the rack an upwardly inclined tail section 5 extends from the last section 2.

The rack is reciprocated or oscillated in the usual manner whereby the straw is stepped up the sides 3 and down the sides A to the section 5 from which it is delivered. During this transit all of the grain and chaff are removed. In the racks now commonly in use much grain islost at the discharge end of the rack'and the rack herein set forth will reduce this loss to a minimum.

On the sides 3 of the section tongues or lugs 6 are provided as by striking up the same fromthe metal of the bottom. These tongues are preferablyarranged in rows transversely of the sections so that their faces are at right angles tothe line of travel of the straw. Openings 7 are provided when the tongues are struck up, but these openings might be otherwise formed. Serrated or notched bars 8 are fastened transversely on the sides 3 and 4 in spaced order and the tongues and openings are disposed between these bars. In the sides 4 openings 9 similar to the openings 7 are disposed between the bars; however the tongues 10 from these openings are bent downward. The section 5 also has the bars 8, openings 7 and tongues 6.

The bars 8 owing to their serrated construction cause the straw to spread over the entire surface of the rack and prevent congestion either transversely or longitudinally of the rack. By thus spreading or thinning the straw the chaff is more readily blown out and the grain is given a better opportunity to separate itself from the straw. As the straw is stepped up the sides 3 the tongues 6 act to retard its progress so that the grain is freed therefrom and may fall through the openings 7 to the riddle (not shown) below. -It is apparent that this retarding of the straw together with the oscillation of the rack will very effectually separate the grain which will be caught by the bars 8 and prevented from rolling down the sides of the sections.

The straw is carried over the ridges of the sections and passes down the sides 4 of the same, the grain being caught by the bars and dropping through the openings 9. There being no tongues in the path of the straw on the sides 4 the straw is not retarded, but is retained in its spread condition by the bars 8 so that grain may be freed. When the straw reaches the section 5 very little if any grain will remain, however this section is made sufliciently long and provided with enough bars 8 and tongues 6 to make for a very eflicient removal of the last grains which are conveyed back by the usual pan 11.

It is pointed out that the tongues 6 will have a tendency to hold the grain and chafi back as the straw progresses and that considerable of the chaff will pass through the openings 7 and 9 with the grain. It is also evident that the capacity of the rack is increased and the separation more quickly performed. r

The invention is presented as including all such modifications and changes as properly come within the scope of the appended claims.

WVhat I claim, is:

1. A straw rack for threshing machines comprising a transversely corrugated bottom the corrugations of which are provided with openings on both sides for the passage of grain, the upwardly inclined sides of the corrugations having projections for retarding the progress of the straw thereover, and transverse serrated bars disposed on the bottom substantially parallel with the ridges of the corrugations.

2. A straw rack for threshing machines comprising a sheet metal bottom trans versely corrugated whereby upwardly and downwardly inclined sides are provided, tongues struck up from the upwardly inclined sides adjacent grain openings, openings in the downwardly inclined sides, said bottom having a comparatively long tail section also provided with the tongues and openings, and serrated bars disposed in spaced order transversely of the bottom on the inclined sides and also on the tail section.

3. A straw rack for threshing machines which includes a transversely corrugated bottom the corrugations of which are provided with openings for'the passage of grain therethrough, means for retarding the progress of the straw along the rack, and straw spreading elements disposed on the upwardly inclined sides of the corrugations of the bottom longitudinally of said corrugations and transversely of the bottom, the openings of the bottom being located between the straw spreading elements whereby the grain caught between the elements is delivered to the openings.

In testimony whereof I affix my signature.


Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washington, D. C.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2642993 *Aug 7, 1950Jun 23, 1953Henry F StraleyScreen for threshing machines
US5588912 *Jul 7, 1995Dec 31, 1996Schumacher, Ii; GustavSieve for harvesting machines
US6843719 *Oct 30, 2003Jan 18, 2005David SacquitneFloating combine sieve assembly
US7104882 *Nov 5, 2004Sep 12, 2006Gustav SchumacherSieve
US20050101362 *Nov 5, 2004May 12, 2005Gustav SchumacherSieve
U.S. Classification460/9, 460/92
Cooperative ClassificationA01D75/282