Separation device

Device for separating fine fractions and coarse fractions from bulk goods, comprising a frame and a screen plane supported by it for supporting the coarse fraction and allowing the fine fraction to pass through, the screen plane being formed by a number of screen disks, that have been arranged in groups and detachably on rotating driven shafts, the shafts on both sides being bearing mounted with bearing ends in first and second bearings on the frame and at at least one end being in driven engagement with driving means, the bearing ends being divided into a shaft member permanent to the shaft and a bearing member bearing mounted in the first and second bearings on the frame, which bearing member inter-engages with the permanent shaft member for co-rotation therewith, wherein in both bearing ends the permanent shaft member and the bearing member can be coupled to each other and can be uncoupled from each other by a movement of the shaft transverse to the main direction of the shaft.

TECHNICAL FIELD

The invention relates to a separation device, enabling to separate fine fractions, such as soil or earth, from coarse fractions, such as tuberous plants.

BACKGROUND OF THE INVENTION

Such separation devices are generally known, and have for instance been described in applicant's Dutch patent application 90.02165. The separation devices comprise a frame in which a number of parallel driven shafts have been bearing mounted, on which shafts star-shaped disks have been arranged, which engage between each other and during rotation, due to the rotating fingers, form a vibrating bed for the material to be treated. In an embodiment the shafts have a flange plate at one shaft end, which flange plate is detachably bolted to a second flange plate having an axle stub extending through the frame plate, which axle stub has been bearing mounted in a bearing and has been provided with a sprocket wheel, which is in engagement with a drive chain or drive belt. At the other shaft end the shaft has been extended with a threaded axle stub, which has been bearing mounted in a bearing attached to the side of a frame plate facing away from the shaft, wherein a pressure ring has been mounted between the shaft and the frame plate. The star-shaped disks have been axially slid on the square shaft and are kept spaced apart by spacer bushes. When replacing the disks or spacer bushes first the flange plates are detached from each other, the threaded axle stub and the bearing at the other shaft end are disassembled, and the shaft is lifted at both ends to be upwardly removed from the device. After removal of the pressure ring the disks and spacer bushes can be slid from the shaft. For the replacing of the disks and bushes situated more towards the flange plate all disks and bushes situated in front of them, at the side of the pressure ring, have to be removed, also when only those disks have to be replaced. The replacement of the disks and/or spacer bushes thus requires a lot of effort and time, particularly considering the large number of shafts (for instance twelve) which then have to be disassembled.

It is an object of the invention to improve on this.

It is a further object of the invention to provide a device of the type mentioned in the preamble, in which the shafts are easy to disassemble.

SUMMARY OF THE INVENTION

From one aspect the invention to that end provides a device for separating fine fractions and coarse fractions from bulk goods, comprising a frame and a screen plane supported by it for supporting the coarse fraction and allowing the fine fraction to pass through, the screen plane being formed by a number of screen disks, that have been arranged in groups and detachably on rotating driven shafts, the shafts on both sides being bearing mounted with bearing ends in first and second bearings on the frame and at at least one end being in driven engagement with driving means, the bearing ends being divided into a shaft member permanent to the shaft and a bearing member bearing mounted in the first and second bearings on the frame, which bearing member inter-engages with the permanent shaft member for co-rotation therewith, wherein in both bearing ends the permanent shaft member and the bearing member can be coupled to each other and can be uncoupled from each other by a movement of the shaft transverse to the main direction of the shaft.

In this way both actual bearings can remain in their places when removing the shaft, as a result of which the disassembling/assembling time is reduced. Because the disks and bushes can be reached from both ends time and effort are further saved on.

Preferably the coupling/uncoupling motion is radial to the shaft, so that the shaft can be removed (or be placed again) in a motion which is as short as possible.

The removal/placement of the shaft is further facilitated when the coupling/uncoupling motion for both bearing ends has the same direction.

In the device according to the invention it is possible due to the use of a coupling connection to provide the bearing members with support surfaces for the shaft members to be coupled therewith, so that also when the connection has not been locked or secured yet (in case of assembling) or when the locking has been loosened (in case of disassembling) the shaft sits stably, leaving the hands free to carry out other (assembly) activities.

Preferably the shaft members and the bearing members have been provided with snugly fitting male and female parts, which preferably are substantially radially oriented and preferably taper in radial direction. The coupling can thus be performed in a simple and reliable manner.

In a further embodiment of the device according to the invention means have been provided for locking the coupling of the permanent shaft member and the bearing member. Preferably the locking means comprise a locking member which extends through the permanent shaft member and the bearing member, and which remains free from the bearings and engages on the shaft. The coupling can thus be released and locked again independent from the bearings. In a preferred embodiment the locking member is a threaded bolt, engaging into a threaded bore permanent to the shaft and supporting with the head on the bearing member. Preferably the shaft is hollow and at the ends has been provided with blocks or pins clamped in there, which blocks or pins have been provided with threaded bores. The shaft can have any desired cross-section, particularly unround, as a result of which the transfer of rotation forces on the disks is enhanced.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The separation device1inFIG. 1comprises a frame100having longitudinal sides3and4, where bearings5and6have been arranged in which shafts9a,9bprovided with wheels10, particularly star-shaped wheels10, have been bearing mounted. At the side of the bearings5sprocket wheels7have been attached on the shafts9a,9b, which sprocket wheels are in engagement with schematically shown driving means8, such as one or more chains, which are driven by a motor that is not further shown, to let the shafts9a,9beach rotate about their own centre line. InFIG. 1it can be seen that the wheels10of adjacent shafts9a,9bhave been positioned staggered with respect to each other, so that they are able to engage between each other. The goods/materials to be separated are dumped on the bed formed by the plurality of wheels, after which through rotation of the shafts9a,9bthe fine fraction is separated from the coarse fraction and can fall down between the wheels. This is a technique known per se.

The shaft9ashown inFIG. 2comprises a square tube12(a solid rod can also be used), onto which a number of wheels10have been slid, which are kept spaced apart by spacer tube members11that have also been slid onto the tube12. The ends of the tube12extend through partitions31,32which for instance are 1.50 m long (in a direction perpendicular to the plane of the drawing), and by means of bolts13have been detachably attached to the side walls19and20of the longitudinal sides3and4of the frame100.

Both ends of the tube12have been accommodated in a rotation-fixed manner in first coupling disks21, shown inFIGS. 3A,4A and4B. Said first coupling disks21are substantially circular, and have a passage23, which, as can be seen inFIG. 3A, is stepped, having a square portion23a, for snug accommodation of an end of the tube12(also seeFIG. 5), a portion23b, for fitting accommodation of an end portion14aof an insert pin or insert block14(FIG. 5) yet to be discussed, and a portion23cin which a locking ring for attachment of the disk21on the shaft end can be accommodated. The passage23opens into a radial slit or groove25, which slightly tapers radially to the outside and has a bottom area30.

In the end of the tube12, as can be seen inFIG. 5, a pin or block14has been placed and welded to it. The pin14has a narrowed portion14aextending outside the end of the tube12, which portion14acan be accommodated in the passage portions23band23cmentioned above. The pin14has furthermore been provided with a threaded bore15.

The second coupling disk shown inFIGS. 3B and 4Calso is substantially circular, and has a hub bush27welded onto it. A bore24runs through disk and hub bush, in which bore a broadened portion24aand a narrower portion24bcan be distinguished. As can be seen in the figures the second coupling disk22has been provided with a radial thickening26, which slightly tapers radially to the outside, to the same degree as recess25of the first coupling disk21, and which forms a support surface31. The thickening26snugly fits in the recess25, in order to bring the first and second coupling disks into coupling engagement with each other transferring a moment of torque, so that they can form one rotatable unit (seeFIG. 5), the bottom end30supporting on the support surface31. Due to the fitting tapering accommodation of thickening26in recess25, support may also be found along the other side areas that diverge from each other.

InFIG. 5the coupling disks21and22have been brought into engagement with each other, and the hub bush27extends through a hole40in wall20and has been bearing mounted in bearing portion41of bearing6. From the outside a threaded bolt16extends, which with threaded portion18has been brought into threaded engagement with the threaded bore15. The head17of threaded bolt16abuts the end of the hub bush27, so that both coupling disks21,22are kept firmly pressed against each other and in axial and radial direction remain together.

A comparable arrangement having first and second coupling plates is present on the left hand side ofFIG. 2, although there the hub bush27′ of the second coupling disk22′ will be extended, to offer room to sprocket wheel7, which will be attached to it in a rotation fixed manner.

In theFIGS. 6A–Cit has been schematically shown how the shaft9acan be removed in an easy manner, which may be necessary in order to replace wheels10by new ones or differently shaped ones, or to replace the spacer bushes11by shorter or longer spacer bushes.

To that end first the partitions31,32are removed, which is easy to do by loosening the bolts13. The coupling disks21,22,22′ at both shaft ends are then accessible. It is ensured that the pairs of coupling disks are oriented such that the thickenings26,26′ face upwards with their upper surface31, and are substantially vertical. Subsequently the threaded bolts16,16′ are loosened at both shaft ends and they are removed (direction A), in order to overcome the clamping forces and shearing forces on both coupling disks at each shaft end, seeFIG. 6B. Despite the removal of the threaded bolts16,16′ the shaft9awill remain sitting stably, because the coupling disks21,21′ remain resting with the edges (30) of their recesses25,25′ on the edges (31) of the thickenings26,26′ of the coupling disks22,22′. Both coupling disks21,22,21,22′ can now be removed from each other, by moving the shaft9ahaving the first coupling disks21at the ends, with respect to the remaining second coupling disks22,22′ in a direction which is radial and indicated with B inFIGS. 3,4A and5. Note that the direction B has also been indicated inFIG. 6C, now upwards, which in connection with the accessibility is easier. As can be seen inFIG. 6Cthe shaft9ahaving the first coupling disk21at the ends, can be removed straight upwards, without the bearings5and6having to be touched while the second coupling disks22,22′ can remain in their places. After removal of the locking rings the disk21in question at the selected shaft end can be removed, and the wanted wheels and/or spacer bushes can be replaced.

The placing again of the shaft9atakes place in a simple manner in reverse direction, wherein the recess25is slid again over the thickening26until both coupling disks21,22fit together again, and the shaft9ais kept stably again by the recesses25,25′ lying on the thickenings26,26′. Thus the hands are then left free to arrange and tighten threaded bolts16.