Impeller for axial flow combine

BACKGROUND OF THE INVENTION

The present invention relates generally to improvements in combines and the like and more particularly to a new and improved rotor for axial flow type combines. The rotor is for use on axial flow type combines of the type having an end feed arrangement and includes impeller blades adapted to accept j material being fed axially into the cylinder of the combine.

In all present commercially available combines the material to be threshed is fed between a rotary cylinder and a stationary concave in a direction normal to the axis of the rotating cylinder. Much of the gain from the material fed to the cylinder and concave passes through the concave as threshed grain. The remainder of the material is conveyed to the separating components of the combine which in conventional combines includes reciprocating or oscillating straw racks, and chaffer sieves.

This invention concerns a combine that operates on a completely different principle than the above described commercially available combine. In the combine described in the subject application, an elongated rotor is provided along a longitudinal axis of the combine. The elongated rotor is enclosed within a cylinder having transport fins provided along its internal upper surface and a concave and grate along its lower surface. The material to be threshed is fed into the front end of the cylinder and is metered axially toward the rear for processing by the cooperating elements of the rotor and cylinder. In axial flow combines of this type, the rotor revolves at a high rate of speed and there is a rather small clearance between the rotor and the casing thus making it difficult to introduce material into the casing. An attempt to solve the problem of the initial entrance of the unthreshed material into the casing is disclosed in the copending U.S. Pat. application of Knapp et al., Ser. No. 590,794 filed on Oct. 31,1966, now Pat. No. 3,464,419, issued Sept. 2, 1969. The subject invention represents applicant’s contribution to the machine disclosed in the above referred to Knapp et al. application. In the machine disclosed in the Knapp et al. application, the impeller blades were originally in the form of several auger flights. Although these original impeller blades performed acceptably, there was a tendency to reject some material being fed into the casing and this objection was accentuated when the volume of material was increased.

SUMMARY OF THE INVENTION

The general purpose of this invention is to provide an end feed assembly for an axial or rotary thresher which embraces all the advantages of similarly employed end feed arrangements and possesses none of the aforedescribed disadvantages. To attain this, the present invention contemplates the use of a plurality of impeller blades having a generally rectangular shape and extending tangentially from the core of the rotor. A scooped portion is formed along the forward and outer edges of each impeller blade. It has been shown through comparative tests that applicant’s impeller blades are an improvement upon the original auger-shaped impellers, since they will permit material to be accepted by the casing at a greater rate. It has been found that when using the subject impeller blades, that after the initial entrance of the material into the casing that very little is backfed or discharged through the entrance opening. The scoop portion of the subject impellers is considered to be responsible for the improved acceptance rate and the tangential attitude of the impeller responsible for its lack of backfeeding.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a side view of an axial flow combine having a portion cut away so that internal elements of the combine can be seen;

FIG. 2 is a plan view of the forward end of the tubular casing and cowling portion;

FIG. 3 is an isometric schematic view taken from the rear of the tubular casing and cowling;

FIG. 4 is a pictorial view of the impeller portion of the rotor; FIG. 5 is a side view of the impeller portion of the rotor; and FIG. 6 is a front view of the impeller portion of the rotor taken along lines 6,6 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings wherein like reference characters designate like or corresponding parts throughout the several views there is shown in FIG. 1, an axial flow type combine generally designated 10. The combine includes drive wheels 11, dirigible wheels 12, a grain platform 13, an opera15 tor’s cab 14, a grain tank 15, an engine 16, and a cleaning system 17. As can be seen in FIG. 1, through the cutaway portion of the grain platform 13, there is an undershot conveyor 18 and a compressor roll 19.

The axial flow combine 10 has a tubular casing 20 formed 20 about a fore-and-aft axis A-A. The forward end 21 of the tubular casing 20 is located adjacent the compressor roll 19 such that unthreshed material conveyed by the grain platform 13 is fed into the forward end 21 of the tubular casing 20. The upper portion of the tubular casing 20 is made of sheet materi25 al that is impervious to the passage of the harvested crop. The bottom forward portion of the tubular casing 20 is formed by a concave 35 made up of bars and rods similar to the concave in a conventional combine. The bottom rear portion of the tubular casing 20 is formed of a grate 36. The grate 36 can be con³θ structed of perforated sheet material. A plurality of transport fins 22 protrude inwardly from the upper portion of the tubular casing and are arranged such that they will function to move the material from the forward end of the tubular casing towards the rear end.

Referring now to FIGS. 2 and 3, it should be noted that the forward end 21 of the tubular casing is defined by an irregularly shaped front inlet edge. The irregularly shaped front inlet edge has a summit 26, a first apex 24 and a second apex 25. A 40 cowling means 27 is connected to the tubular casing 20 along said irregularly shaped front inlet edge. First and second lines 37 and 38, respectively, diverge rearwardly and downwardly from the summit 26 to the first and second apexes 24 and 25, respectively. The first and second apexes 24 and 25 are each 45 located above the fore-and-aft axis A-A of the tubular casing and the first apex 24 is located rearwardly of the second apex 25. The inlet edge continues from the first apex 24 along a vertical line 39 to a point below the fore-and-aft axis A-A and then forward along a first parallel line 40. The inlet edge con50 tinues from the second apex 25 forward along a second parallel line 41. It should be noted that the first parallel line 40 is parallel to and below the fore-and-aft axis A-A and that the second parallel line 41 is above and parallel to the fore-and-aft axis A-A.

The cowling means 27 as disclosed herein is fabricated from several pieces of sheet material. However, it should be noted that it is the contour of the internal surface of these sheets that is critical to the proper functioning of the cowling. The cowling means could, of course, be constructed of a casting or other equivalent construction. The cowling means 26 has a pair of curved upper internal surfaces 28. The curved surfaces 28 have first edges 29 that are joined to the tubular casing along the first and second lines 37 and 38. Curves surfaces 28 ₆₅ has second edges designated 32 that diverge forwardly from the first and second apexes 24 and 25. The curves surfaces 28 have third edges designated 42 that lie in a plane transverse to the fore-and-aft axis A-A and define an inverted U-shaped rim.

The cowling means further include a first internal lower surface 43 that is made up of a bottom plate 44 and a side plate

45. The bottom plate 44 has a first edge designated 46 secured to the tubular casing along first parallel line 40. The side plate has a second edge designated 47 that diverges forwardly from the apex 24 and is joined to the second edge 32 of the

3.537.460 curved surface 28. The bottom plate 44 is joined to the side plate 45 along a common edge 48.

The cowling means 27 further includes a second internal surface designated 49 having a first edge 50 that is joined to the tubular casing 20 along the second parallel line 41. The second internal surface 49 has a second edge 51 that is joined to the curved surface 28 along its second edge 32.

A generally horizontal feed surface designated 33 having a rear edge 34 extends across the open portion of the inverted U-shaped rim forming the lower portion of the cowling. The rear edge 34 defines the lower boundary of the tubular casing inlet opening. The bottom half of the tubular casing is closed by an end plate 52 as can be best seen in FIG. 3. An elongated stripper blade 53 protrudes from the internal surface of the tubular casing 20 commencing at a point below the fore-and-aft axis A-A at the forward end of the tubular casing and extends in a direction towards the second apex 25. The first transport fin in the series of spiral transport fins 22 begins at a point designated 54 in FIG. 2 adjacent the inverted U-shaped rim of the cowling means and offset from the summit 26 in the direction towards said second apex 55. The first transport fin is extended downwardly and rearwardly in a direction towards the first apex 24. This is to prevent material from being backfed from the cowling onto the feed surface 33.

As can be best seen in FIG. 1, an elongated rotor 60 is journaled for rotation about the fore-and-aft axis A—A within the tubular casing 20. The elongated rotor 60 has a central hub 61 with a forward end 62 corresponding to the forward end 21 of the tubular casing 20. Drive means 63 extend from the hub 61 to the engine 16 for driving the elongated rotor 60. A plurality of impeller blades 64 extend from the forward end 62 of the hub 61.

In the embodiment disclosed herein, three impeller blades 64 are equally spaced around the periphery of the hub. As can be best seen in FIGS. 4 through 6, inclusive, each of the impeller blades is formed of a rectangular plate 65 having a base edge 66, a forward edge 67, a rear edge 68, and an outer edge 69. The base edge 66 of the rectangular plate is secured to the hub and the rectangular plate extends tangentially from the hub. Each impeller blade has a scoop portion designated 70. The scoop portion 70 is formed by bending the rectangular plate along a bent line designated 71 running from the forward edge 67 to the outer edge 69. A support plate 72 is provided for each of the impeller blades. The support plate 72 extends radially from the hub 61 and is secured to the trailing surface 73 of the rectangular plate 65. As can be seen in FIGS. 4 and 5, the support plate is located adjacent the rear edge 68 of the rectangular plate 65.

The portion of the elongated rotor rearwardly of the impeller blades 64, (See FIG. 1) comprises a plurality of radially extending arms 80 terminating in free ends adjacent the internal surface of the tubular casing 20. The radially extending arms 80 are arranged such that longitudinally extending members 82 parallel to the fore-and-aft axis A-A can be connected to their free ends. The space between the hub 61, the radially extending arms 80, and the longitudinally extending members 82, is filled by grates 83 constructed of bars or the like.

The agricultural crop to be harvested is severed and accumulated by the grain platform 13 and is then elevated by the undershot conveyor 18. The undershot conveyor 18 deposits the material on the feed surface 33 below the compressor roll 19. The material is then fed as a sheet by the compressor roll 19 towards the inlet opening of the tubular casing 20. As this sheet of material progresses beyond the rear edge 34 of the feed surface 33, it encounters the impeller blades 64 of the elongated rotor 60 and the contoured surface of the cowling 27. Since the sheet of material is being fed axially of the elongated rotor 60 along a plane above the fore-and-aft axis A—A, it will encounter the impeller blades 64 moving downwardly on one side of the axis A-A and moving upwardly on the other side of the axis. For the purposes of this explanation, the righthand side of the tubular casing 20 will be considered the side to the right of the operator as he faces forward when on the operator’s platform. The rotor as seen in FIG- 6 rotates in a clockwise direction. Thus the portion of the strip of material on the left-hand side of the axis A-A will encounter the impeller blades 64 moving downwardly and that portion to the 5 right of the axis A-A will encounter the impeller blades 64 moving upwardly.

For the purpose of this explanation, the strip of material will be divided into two halves, the left half and the right half. The left half of this· strip of material enters the cowling 27 on the 10 side having the first internal lower surface 43. The outer edge of the strip of material will fall by gravity towards the bottom plate 44 which is arranged such that the material will slide inwardly towards axis A-A. The axial momentum of the material will continue to move it rearwardly and the side plate 45 will ¹⁵ be encountered. The side plate 45 is arranged such that it will direct the material inwardly towards axis A-A. Eventually, this material will pass inwardly over the first parallel line 40 where it will be carried in a clockwise direction over the concave 35 by the elongated rotor 60.

^2U As the left half of the strip of material moves rearwardly beyond the rear edge 34 of the feed surface 33, it encounters the forward edge 67 of an impeller blade 64 which is moving downward relative to the material. The apex of the scoop por₂₅ tion 70 formed by the intersection of the forward edge 67 and the outer edge 69 makes the initial contact with the material. Following this initial contact the material strip which is severed by the forward edge 67 is moved downwardly by the impeller blade. The scoop portion 70 of the impeller blade 30 functions to impart a rearward and inward component of force to the material and significantly reduces backfeeding of material. As this material begins to move up to the right-hand side of the tubular casing it will encounter the elongated stripper blade 53 which will cause the material to move rear35 wardly towards the second apex 25. Thus all material fed into a left-hand side of the tubular casing will be carried down and across a concave and will be indexed rearwardly beyond the second apex 25 to insure that it cannot be backfed as the rotor moves upwardly from the second parallel line 41.

The outer edge of the material feeding into the right-hand side of the tubular casing 20 will be supported by the flat second internal surface 49 and will be deflected inwardly by the curved upper surface 28. The material will eventually encounter the spiral transport fins 22 and will be indexed rear45 wardly by this series of fins.

It should be noted that the material fed into the left-hand side can travel in excess of 180° around the tubular casing before it reaches the second apex 25 while the material fed into the right-hand side must reach the first apex 24 in less than ⁵⁰ 180° of travel. For this reason, the second apex 25 is located forwardly of the first apex 24 causing the material on the righthand side to be deflected inwardly towards the axis A-A at a sharper angle than the material on the left-hand side.

Not only does the agricultural material fed into the cowling, ⁵⁵ follow the rearwardly directed path described above but the air also follows this path. Thus a stream of air flows through the cowling 27 and axially along the tubular casing. The dust and chaff created by the undershot conveyor 18 and the com60 pressor roll 19 is carried along with this stream of air and thus the problem of dust backing down the grain platform 13 is minimized.