GB2054335A - Sieves - Google Patents

Abstract

A sieve for a combine harvester comprises parallel louvres rotatably mounted in opposite side walls of a frame. Each louvre is a plastics moulding comprising aligned blades 25, 26, 27 joined by integral cylindrical portions 28. These portions are journalled in split bearings 30, 31 which, in turn, snap-engage in slots 34 in reinforcement bars 22, 23 of the frame. The ends of the louvres define journals 29, which engage in slots 32 in wooden battens 16 defining the side walls. An adjustment bar 41 engages cranked portions 40 of the louvres for angularly adjusting the louvres relative to the frame. <IMAGE>

Description

SPECIFICATION Sieves This invention relates to sieves of the type used in combine harvesters.

Such sieves usually have parallel rows of elongate blades each swivellably mounted in bars of a frame for angular adjustment about a longitudinal axis and means for holding the blade in angularly adjusted positions. Such sieves are used in combine harvesters for separating grains from chaff, which is blown off the sieves.

Such sieves are liable to wear, particularly through vibration. The blades are usually made of pressed metal and are mounted on metal rods which are journalled in the bars of the frame to provide the swivel mounting. These journals, formed by the rods, eventually wear such that the blades pivot out of the adjusted position or come adrift completely from the frame.

The present invention provides a sieve which avoids these problems.

In accordance with this invention, there is provided a sieve comprising a frame having opposed parallel side walls, a plurality of parallel louvres extending between the side walls and each rotatably mounted at each end in a respective one of the side walls, a plurality of bars fixed in the frame and extending in spaced parallel relationship to the side walls, each louvre being a plastics moulding and comprising a plurality of aligned blades joined longitudinally by integral journals, each journal being rotatably engaged in a respective one of the bars, and adjustment means for angularly adjusting the louvres relative to the side walls.

Reference is now made to the accompanying drawings, wherein the sole figure is a perspective view of parts of a combine harvester sieve.

The sieve shown comprises a frame including a perimeter frame 11 of rectangular form. The perimetes frame comprises elongate metal strips such as 12, 13 extending along each side of the frame. The strips are of channel form and house wooden battens 15, 16 secured in position. The battens are joined together by corner pieces, such as 17, 18, so as to complete the perimeter frame. The corner pieces may be plastics mouldings having ridged projections, such as 19. These projections engage in sockets, such as 20 in the battens and may be adhered in position.

The frame includes bars, such as 22, 23 extending parallel to each other and to two sides of the frame, at spaced intervals along the frame. These bars may be welded to the strips 12 or otherwise secured in position.

Blades or vanes, 25,26,27 are mounted in the frame in rows. Each blade is located between a pair of bars 22,23 or between a bar and a side wall of the frame, such as defined by the batten 16. The blades in each row are integrally formed as parts of a single plastics moulding (e.g., injection moulded) to form a louvre, the blades being interconnected by integral cylindrical portions defining journals 28. Each end of the moulding is also formed with a journal, such as 29.

The journals are snap-engageable in hollow cylindrical bearings 30,31 made of low-friction plastics material, such as nylon. Snap-engagement is permitted by a longitudinal split, such as 33, in each bearing, the material being sufficiently resilient to permit the necessary temporary deformation. The bearings snap-engage in keyhole slots 34, 35 in the bars 22, 23. The end journals 29 engage in open-ended slots in the wooden battens, such as slot 32 in the batten 16 and these slots may include plastics linings to reduce friction. The channel strip 13 closes the open end of the slot 32.

Each louvre moulding includes a cranked portion 40 in one of the cylindrical portions. These cranked portions are mutually aligned and rotatably engage in an adjustment bar 41. The adjustment bar also includes keyhole slots 42 mounting bearings 43 in which the cranked portions snap-engage. The adjustment bar is longitudinally adjustable in position to vary the angles of the blades, in known manner.

The described construction is strong and the journals are resistant to wear by vibration, due to the position of the bearings. The louvres can be very easily fitted in position and easily replaced if necessary. Individual blades in each louvre cannot come apart from other blades and become twisted out of position or detached.

1. A sieve comprising a frame having opposed parallel side walls, a plurality of parallel louvres extending between the side walls and each rotatably mounted at each end in a respective one of the side walls, a plurality of bars fixed in the frame and extending in spaced parallel relationship to the side walls, each louvre being a plastics moulding and comprising a plurality of aligned blades joined longitudinally by integral journals, each journal being rotatably engaged in a respective one of the bars, and adjustment means for angularly adjusting the louvres relative to the side walls.

2. A sieve according to Claim 1,wherein each bar mounts cylindrical bearings which receive said journals.

3. A sieve according to Claim 2, wherein each bearing snap-fits into a slot in the corresponding bar.

4. A sieve according to Claim 3, wherein each bearing is longitudinally split and is sufficiently resiliens to be temporarily deformed for fitting a journal in the bearing.

5. A sieve according to any preceding claim, wherein the side walls are composed of wooden battens which are housed in channel-shaped metal members.

6. A sieve according to Claim 6, wherein the side walls are connected to other frame members to define a rectangular frame, and corner pieces joining the frame members to the side walls by engaging with the wooden battens.

7. A sieve constructed substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Sieves This invention relates to sieves of the type used in combine harvesters. Such sieves usually have parallel rows of elongate blades each swivellably mounted in bars of a frame for angular adjustment about a longitudinal axis and means for holding the blade in angularly adjusted positions. Such sieves are used in combine harvesters for separating grains from chaff, which is blown off the sieves. Such sieves are liable to wear, particularly through vibration. The blades are usually made of pressed metal and are mounted on metal rods which are journalled in the bars of the frame to provide the swivel mounting. These journals, formed by the rods, eventually wear such that the blades pivot out of the adjusted position or come adrift completely from the frame. The present invention provides a sieve which avoids these problems. In accordance with this invention, there is provided a sieve comprising a frame having opposed parallel side walls, a plurality of parallel louvres extending between the side walls and each rotatably mounted at each end in a respective one of the side walls, a plurality of bars fixed in the frame and extending in spaced parallel relationship to the side walls, each louvre being a plastics moulding and comprising a plurality of aligned blades joined longitudinally by integral journals, each journal being rotatably engaged in a respective one of the bars, and adjustment means for angularly adjusting the louvres relative to the side walls. Reference is now made to the accompanying drawings, wherein the sole figure is a perspective view of parts of a combine harvester sieve. The sieve shown comprises a frame including a perimeter frame 11 of rectangular form. The perimetes frame comprises elongate metal strips such as 12, 13 extending along each side of the frame. The strips are of channel form and house wooden battens 15, 16 secured in position. The battens are joined together by corner pieces, such as 17, 18, so as to complete the perimeter frame. The corner pieces may be plastics mouldings having ridged projections, such as 19. These projections engage in sockets, such as 20 in the battens and may be adhered in position. The frame includes bars, such as 22, 23 extending parallel to each other and to two sides of the frame, at spaced intervals along the frame. These bars may be welded to the strips 12 or otherwise secured in position. Blades or vanes, 25,26,27 are mounted in the frame in rows. Each blade is located between a pair of bars 22,23 or between a bar and a side wall of the frame, such as defined by the batten 16. The blades in each row are integrally formed as parts of a single plastics moulding (e.g., injection moulded) to form a louvre, the blades being interconnected by integral cylindrical portions defining journals 28. Each end of the moulding is also formed with a journal, such as 29. The journals are snap-engageable in hollow cylindrical bearings 30,31 made of low-friction plastics material, such as nylon. Snap-engagement is permitted by a longitudinal split, such as 33, in each bearing, the material being sufficiently resilient to permit the necessary temporary deformation. The bearings snap-engage in keyhole slots 34, 35 in the bars 22, 23. The end journals 29 engage in open-ended slots in the wooden battens, such as slot 32 in the batten 16 and these slots may include plastics linings to reduce friction. The channel strip 13 closes the open end of the slot 32. Each louvre moulding includes a cranked portion 40 in one of the cylindrical portions. These cranked portions are mutually aligned and rotatably engage in an adjustment bar 41. The adjustment bar also includes keyhole slots 42 mounting bearings 43 in which the cranked portions snap-engage. The adjustment bar is longitudinally adjustable in position to vary the angles of the blades, in known manner. The described construction is strong and the journals are resistant to wear by vibration, due to the position of the bearings. The louvres can be very easily fitted in position and easily replaced if necessary. Individual blades in each louvre cannot come apart from other blades and become twisted out of position or detached. CLAIMS

1. A sieve comprising a frame having opposed parallel side walls, a plurality of parallel louvres extending between the side walls and each rotatably mounted at each end in a respective one of the side walls, a plurality of bars fixed in the frame and extending in spaced parallel relationship to the side walls, each louvre being a plastics moulding and comprising a plurality of aligned blades joined longitudinally by integral journals, each journal being rotatably engaged in a respective one of the bars, and adjustment means for angularly adjusting the louvres relative to the side walls.

2. A sieve according to Claim 1,wherein each bar mounts cylindrical bearings which receive said journals.

3. A sieve according to Claim 2, wherein each bearing snap-fits into a slot in the corresponding bar.

4. A sieve according to Claim 3, wherein each bearing is longitudinally split and is sufficiently resiliens to be temporarily deformed for fitting a journal in the bearing.

5. A sieve according to any preceding claim, wherein the side walls are composed of wooden battens which are housed in channel-shaped metal members.

6. A sieve according to Claim 6, wherein the side walls are connected to other frame members to define a rectangular frame, and corner pieces joining the frame members to the side walls by engaging with the wooden battens.

7. A sieve constructed substantially as herein described with reference to the accompanying drawings.