RU2631398C1 - Lipped screen - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: lipped screen contains the swing doors installed on the frame and elements for additional turning of the thrashed heap, which are made in form of finger combs, fixedly mounted in the frame between the swing doors. The base of finger combs is oriented along the axes of the swing doors. Fingers of combs are made of spring steel, cantilever fitted at the base of the comb with orientation of console part in the direction of thrashed heap movement. Combs are located above the screen surface with the possibility of providing full opening of swing doors of lipped screen. Finger combs are installed in the frame with overlapping each other.

EFFECT: lipped screen provides effective separation of grain heap.

5 cl, 5 dwg

Description

FIELD OF THE INVENTION

The invention relates to agricultural machinery, and in particular to grain cleaning devices of combines and threshers.

State of the art

Known regular sieves of combine harvesters do not have high aerodynamic properties and practically do not affect the looseness of the descending grain heap. Poor looseness of the grain heap, especially when harvesting wet crops, complicates its separation and leads to large losses of grain behind the sieve.

Known solutions in which to improve the loosening of the grain heap fed to the sieve, they resort to improvements in the finger comb mounted on the end of the stripping (transport) board located above the sieve (see patent SU 1271441, publ. 23.11.86, or patent SU 1192707, publ. 11/23/85).

There are devices in which, in order to reduce grain losses and improve separation of grain heaps, an additional cascade is placed between the transport board and the sieve mill in the form of an intermediate louvre sieve with a finger comb at the end, for example, as in the known cleaning of a combine harvester according to patent RU 2023367, IPC A01F 12 / 44, publ. 11/30/94. However, the introduction of an additional sieve requires substantial refinement of the supporting structure of the sieve mill, which complicates its subsequent maintenance.

All of the above counterparts solve the problem of poor separation of the grain heap without touching the design of the louvre sieve.

A technical solution is known in which the looseness of the grain heap is improved by increasing the aerodynamic characteristics of the louvre sieve and creating additional air jets stitching from the bottom up the grain heap due to the use of rotary plates with flat combs and streamlined rake teeth (see patent RU 2397634, IPC A01F 12/44, published on August 27, 2010).

However, this improvement may not be enough, for example, when harvesting wet crops.

As the closest analogue to the claimed technical solution, a louvre sieve was adopted, containing pivoting flaps installed in the frame with teeth-protrusions forming a comb along the upper edge of the flap, and elements for additional tedding of the pile (patent SU 388797, IPC A01F 12/44, published 05.07 .73). In the mentioned solution, the elements of additional tedding of the heap are made in the form of strings, which are stretched between the teeth-protrusions of the rotary wings and fixed on the extreme wings. In the process of reciprocating movement of the sieve strings perform oscillatory movements, providing additional tedding heap.

The disadvantages of the known louvre sieve should include a low intensity of exposure to the heap from the side of the additional tedding. The strings act only on the lowermost layers of the heap, falling between the leafs of the blinds, while the mass of the heap lying on the surface of the sieve presses from above, which significantly reduces the intensity of the vibrations of the strings. As a result, poor separation of the grain heap and high grain losses behind the sieve.

The technical problem to be solved by the claimed invention is directed is the creation of conditions for the efficient separation of the grain heap directly on the sieve by improving its design.

Disclosure of invention

The aforementioned problem has been solved in the proposed louvre sieve, comprising pivoting sashes and elements for additional tedding of heaps installed in the frame. According to the claimed invention, the elements of additional tedding of heaps are made in the form of finger combs fixedly installed in the frame between the rotary leaves of the finger combs with a base oriented along the axes of the rotary valves and spring steel fingers cantilevered in the base of the comb with the orientation of the cantilever part in the direction of movement of the heap and its placement above the surface of the sieve, providing the ability to fully open the rotary wings, while the finger combs are installed in the frame of the sieve with overlapping each other.

The technical result achieved by using the claimed invention is to increase the efficiency of separation of grain heap due to the possibility of separation of the heap into large and small fractions and to perform independent separation of each fraction on one sieve.

The mentioned technical result is provided due to the distinctive design features of the proposed sieve, namely:

- performing elements of additional tedding of a heap in the form of finger combs oriented in the direction of movement of the heap, motionlessly installed in the sieve frame between the rotary wings;

- perform finger combs of spring steel;

- placing the fingers in such a way that they do not interfere with the operation of the swing shutters;

- placement of finger combs with overlapping ends of each other.

Finger combs fixed between the sash flaps form a second tier (cascade) of separation above the sieve blinds in the form of a composite finger grating, characterized by intensive mobility of its constituent elements - fingers made of spring steel.

On the surface of this additionally formed composite lattice, large heavy parts of the heap are retained, which move in the direction of exit along the fingers of the combs above the louvred surface of the sieve, being subjected to intensive shaking from the side of spring fingers and blowing air through the openings of the sieve blinds. As a result, a good swelling of the non-cereal part of the heap is ensured and the process of isolating the purified grain from it is intensified.

Small parts of the heap - refined grain and small straw impurities, separated from the large components of the heap, fall down between the fingers of the combs, where they fall on the louvered surface of the sieve and are separated in a known manner.

Due to the separation of the grain heap entering the sieve and the “cascade” of its processing, the separation efficiency is significantly increased, and grain losses behind the combine are reduced.

Due to the fact that the cantilever parts of the fingers of the combs are located above the rotary shutters in a fully open state, including the rotary shutters closest to the combs, a full and independent operation of the sieve blinds is ensured.

Due to the fact that the finger combs forming an additional tier of separation are mounted directly on the sieve frame, the need for any modifications to the supporting structure of the sieve mill, necessary in the case of an external cascade, is eliminated.

It is advisable and sufficient to install finger combs only on the first, most loaded half of the sieve. In this case, taking into account the length of the fingers of the last comb, a large part of the grain heap is held by a canopy over the louvered surface almost to the last third of the sieve. The fall of a grain pile from the outermost finger combs on the surface of the sieve blinds contributes to additional shaking of the straw and knocking out the peeled grain from it.

The first finger comb is installed in the frame at a distance of 150-250 mm from the beginning of the sieve, which makes it possible to overlap the finger comb of an upstream transport board or intermediate sieve, depending on the specific design of the harvester cleaning device.

Placing the first finger comb at the very beginning of the sieve closer than 150 mm does not make sense, because this section overlaps the upstream comb of the board or intermediate sieve. Placing the first finger comb at a distance of more than 250 mm from the beginning of the sieve will not provide the required overlap of the cascades.

For reliable operation of the device, it is preferable to use welding to secure the fingers of the finger combs. In order to preserve the springy properties of steel and to ensure the intensity of finger vibrations, the base of the finger comb is formed from an angular profile, and holes for installing fingers are made in one of the shelves of the profile. Each finger is passed at one end through the profile hole and secured to its second shelf by welding.

Rectilinear rods can be used as fingers, however, it is more advisable to use curved rods, the initial portion of which adjacent to the base of the comb is located relative to the sieve plane at an angle greater than its end section.

Due to the fact that the angle between the surface of the sieve and the initial portion of the finger adjacent to the place of its fastening is more than 45 °, preferably 50-85 °, the probability of clogging the base of the comb with a straw mass is excluded.

The angle between the surface of the sieve and the end cantilever part of the finger is significantly smaller. The latter is preferably oriented along the sieve, which contributes to the direction of movement of the grain heap to the exit.

As pivoting flaps, it is preferable to use flaps with a flat comb along the upper edge, located between the ridges of the comb with teeth of a grooved shape, bent downward from the plane of the comb by the convexity of the cross section towards the air flow, and with through grooves made along the lower edge of the flap opposite the said teeth. This shape of the rotary flaps contributes to an additional increase in the efficiency of separation of the grain heap due to a more efficient distribution of the fan flow over the sieve and to receive reinforced vertical jets of air coming out from under the comb at the locations of the curved teeth, which contributes to better loosening of the heap.

Brief Description of the Drawings

In FIG. 1 - louvre sieve, general view;

in FIG. 2- shows a digital comb, general view, isometry;

in FIG. 3 - a fragment of the sieve schematically, shows the location of the finger comb relative to the rotary wings;

in FIG. 4 is a sieve, side view, shows the location of the finger combs relative to each other and relative to the board;

in FIG. 5 is a view A from FIG. 4, a top view of the sieve.

The implementation of the invention

The louvre sieve (see Fig. 1) contains a frame 1 with rotary leaves 2 installed in it and elements of additional tedding of a heap in the form of finger combs 3, fixedly installed in the frame 1 between the rotary leaves 2.

Each finger comb 3 (see FIG. 2) includes a bearing base 4 and fingers 5 of spring steel cantilevered therein. The base 4 is formed from an angular profile made with holes 6 in the shelf 7 of the profile.

The fingers 5 at one end freely passed through the holes 6 and secured by welding to the second shelf 8 of the profile.

With this fastening, the portion of the finger 5 damaged by the high temperature effect of welding is not working. In the zone of the hole 6, which serves as the output support, there is already a working section of the rod, on which all spring properties of the steel are preserved, which ensures a high intensity of oscillations of the console-located part of the finger.

The finger combs 3 are mounted in the sieve frame 1 between the pivoting flaps 2, having the base 4 of the combs substantially parallel to the axes of the pivoting flaps and rigidly fixed, for example, by welding.

In this case (see Fig. 3), the cantilever part of the fingers 5 is directed from the base 4 in the direction N of movement of the heap and is located above the rotary flaps 2 in their fully open state. The space formed under the fingers is sufficient for the operation of the leaves 2 and their regulation from fully closed to fully open.

The length of the fingers is selected based on the specific dimensions of the sieve frame and the number of finger combs placed in it, and can be 250-450 mm.

The height of the cantilever part of the fingers above the sieve is at least 70-80 mm, which ensures the formation of a sufficient air gap for the separation of a large fraction of the grain heap.

At a certain distance from the attachment point, the fingers 5 have a bend. Section A of the finger from the fixing point to the bend is located relative to the sieve plane at an angle of more than 45 °, which eliminates clogging of the base of the comb with a straw mass.

The cantilever portion B of the finger is located relative to the plane of the sieve at an angle of less than 45 °, which contributes to a better advancement of the mass of the heap along the sieve to the exit.

The first finger comb 3 ^{1 is} placed from the beginning of the sieve (see Fig. 4-5) at a distance of R = 150-250 mm, which ensures that it overlaps an upstream finger comb 9, mounted on the end of the strip board 10, or in other designs - an intermediate sieve (not shown in the drawings).

When the subsequent finger combs 3 and 3 are installed in the frame 1, the condition for overlapping the combs is satisfied: each subsequent comb overlaps the end of the previous one in a certain section S (see Fig. 4).

Sieve works as follows.

The threshed mass coming out from under the threshing drum is fed along the stripping board 10 to the sieve mill. Passing through the finger comb 9, mounted on the end of the board 10, the grain heap partially loosens and falls on the upper sieve 11 cleaning.

The large and heavy parts of the falling grain heap are delayed by overlapping finger combs 3 ¹ , 3 ² , 3 ³ , forming the primary separation surface — a composite finger grating 12 (see Fig. 5), along which large fractions move to the sieve exit. At the same time, the fingers of 5 combs made of spring steel under the action of vibrations of the sieve make quite intense vibrations and provide intensive shaking of the heavy heap, which contributes to its separation. The overlapping of the finger combs with each other and with the superior comb eliminates the fall of large fractions of the heap on the louvered surface of the sieve.

Small fractions separated from large parts of the heap: refined grain and small straw impurities fall between the fingers of 5 combs down and fall on the louvered surface formed by the rotary shutters of the 2 sieves. Secondary separation takes place here: clean grain falls through the openings of the blinds into the grain hopper, and small straw impurities are carried outside the sieve by the air flow coming out from under the valves.

As the flaps 2, it is preferable to use pivoting flaps with a flat comb along the upper edge, located between the ridges of the comb with teeth of a grooved shape, bent down from the plane of the comb by convexity of the cross section towards the air flow, and with through grooves along the lower edge, designed to accommodate the teeth of the adjacent flap. This shape of the rotary flaps contributes to an additional improvement in the separation of the grain heap due to a more efficient distribution of the fan air flow over the sieve and to receive reinforced vertical jets of air coming out from under the comb at the locations of the curved teeth, which contribute to additional loosening of the heap.

The above example illustrates the preferred use of the proposed technical solution in the upper louvre screen for cleaning the combine harvester, but it does not limit the possibilities of other uses of the invention.

Claims (5)

1. The louvre sieve containing rotary leaves installed in the frame and elements of additional tedding of heaps, characterized in that the elements of additional tedding of heaps are made in the form of finger combs fixedly installed in the frame between the rotary shutters with the base oriented along the axes of the rotary shutters and spring fingers steel, cantilevered in the base of the comb with the orientation of the cantilever part in the direction of movement of the heap and its placement above the surface of the sieve, providing the possibility of the full opening of the rotary wings, while the finger combs are installed in the frame with overlapping each other. 2. The sieve according to claim 1, characterized in that the finger combs are installed in the first half of the sieve, while the first finger comb is placed at a distance of 150-250 mm from the beginning of the sieve. 3. The sieve according to claim 1, characterized in that the base of the finger comb is formed of an angular profile made with a number of holes in one of the shelves, with each finger freely passed by one end through the profile hole and fixed to its second shelf by welding. 4. The sieve according to claim 1, characterized in that the fingers are bent so that the portion of the finger adjacent to the base of the comb is located relative to the sieve plane at an angle greater than its end portion. 5. The sieve according to claim 1, characterized in that the rotary flaps are made with a flat comb along the upper edge, located between the ridges of the comb with teeth of a grooved shape, bent from the plane of the comb downward by convexity of the cross section towards the air flow, and through grooves formed along the lower edge sashes opposite said teeth.

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