WO1983002969A1

WO1983002969A1 - A method of permanently improving the surface drainage from ground fields, preferably grass-covered fields, as well as an apparatus for use by the method

Info

Publication number: WO1983002969A1
Application number: PCT/DK1983/000020
Authority: WO
Inventors: Elo Hurup-Andersen
Original assignee: Elo Hurup-Andersen
Priority date: 1982-02-24
Filing date: 1983-02-23
Publication date: 1983-09-01
Also published as: NO830637L; DK148778B; DK80082A; GB2125664A; BE896006A; SE8300983D0; DK148778C; FI830352L; FI830352A0; SE8300983L; GB8327855D0

Abstract

By a method of permanently improving the surface drainage from a playing field, the ground is cut in a network of narrow, vertical trenches, which are filled with a porous material whereafter the ground cut up is divided into fine particles and distributed across the trenches and in the spaces therebetween. In this manner it is possible in a simple manner to improve essentially the surface drainage. An apparatus for use by the method comprises a framework (1) which can be suspended in the tree-point suspension of a tractor. A horizontal, transverse, rotatable main shaft (4) is mounted on the framework. One or more parallel cutting wheels (5) displaceable to the side are unpivotably mounted on the main shaft, and each cutting wheel comprises a plurality of cutting shovels (6) mounted thereon. The cutting wheel furthermore comprises power transferring means (7) for the transfer of the movement of the power take-off of the tractor for the rotation of the main shaft (4) with cutting wheels (5). The apparatus comprises furthermore two supporting wheels (11) connected to the framework, a scraper (12) situated behind each cutting wheel (5), and a gravel spreader (13) located above said cutting wheels. This gravel spreader is also driven by the tractor through the power transferring means (7) and releases the gravel to the rear above a transverse releasing roller. Subsequently, the gravel is transferred to a hopper unit (15) mounted on the gravel spreader, said hopper opening on to a jointed, horizontally and vertically movable double hopper (16) associated with each cutting wheel (5), whereby said double hopper can release the gravel in the trenches cut up. The framework (1) includes a detachable screening (20) secured above the cutting wheels (5) and the power transferring means (7). The entire framework with associated parts mounted thereon can be raised and lowered in such a manner that cutting wheels, scrapers, hoppers, and supporting wheels are raised from the ground, or so that cutting wheels, scrapers, and hoppers are lowered into said ground while the supporting wheels rest on the ground. As a result, an apparatus is obtained which implies that it is possible in an easy and quick manner to produce some trenches filled with porous material on a grass-covered playing field, said trenches improving the surface drainage.

Description

Title: A Method of Permanently Improving the Surface Drainage from Ground Fields, Preferably Grass-Covered Fields, as well as an Apparatus for Use by the Method.

Technical Field

The invention relates to a method of permanently improving the surface drainage from ground fields, preferably grass- covered fields, especially playing fields, lawns and the like fields.

- Background Art

In plane fields or low-lying fields such as playing fields, lawns, and grassfields, and especially in fields where the ground has a poor permeability, surface water is often a problem after rain for some time or heavy rain squalls. The means previously employed for overcoming this problem have involved rather great investments in the form of lay¬ ing field drains. At the same time these measures may for a longer period have a rather disturbing effect on the use of the grass-covered field in question, e.g. a playing field.

Disclosure of Invention

The object of the present invention is to provide a method permitting an essential improvement of the surface drain¬ age from for instance grass-covered playing fields without ^'causing heavy expenses and long-termed disturbances of the desired use of the field in question.

The method according to the invention is characterised by cutting a network of narrow .and substantially vertical trenches in the grass-covered ground, the depth and mutual distance of said trenches depending on the permeability of the ground, and by subsequently filling the trenches with a porous material whereafter the ground cut up is divided into fine particles and distributed across the trenches and in the spaces therebetween. To a great extent this method can be carried out mechanically and requires only relative— ly inexpensive materials. In a relatively quick manner and at a relatively modest price it is possible to obtain such a great improvement of the surface drainage that an amount of water of about 10 mm water can be drained away almost momentaneously, said amount of water corresponding to the volume of the filled trenches. This means that simulta¬ neously the biological activity and the acticity of the earthworms are increased which loosens the ground addition¬ ally and intensifies the draining effect far ahead. In addition the disturbance of the use of the field in ques- tion is very short partly because the treatment is quickly carried out, and partly because the trenches cut up are so narrow that for instance a football field is ready for playing immediately after termination of the treatment, and furthermore because the grass respreads quickly across the trenches.

Experience has shown that it is practical and sufficient to situate the trenches substantially parallel to each other and only in one direction, and these trenches are in response to the ground conditions situated at intervals of between about 40 cm and about 200 cm, preferably between about 60 cm and about 120 cm.

According to a preferred embodiment of the method the trenches are o^'f a width of between 3 cm and 10 cm, prefer¬ ably about 4 cm, and a depth of up to 40 cm, preferably between 10 cm and 30 cm.

By condensing the porous material according to the inven¬ tion during and/or after the filling thereof into the trench, it is obtained that the material does not settle after the treatment. OMFI When particularly great requirements are presented to the appearance of the surface of the trenches, it is according to the invention possible to coat the surface of the filled trench with a thin, preferably reinforced strip of grass mat and to press said mat into the trench before the ground cut up is distributed.

The dividing into fine particles and distribution of the ground cut up across the trenches and in the spaces there¬ between are advantageously carried out by means of a drag net in the form of a net attached to a transverse bar and stretched out by iron chains and pulled after a tractor.

The invention furthermore deals with an apparatus for use when carrying out the method, said apparatus being charact¬ erised in that it comprises a framework including means for its suspension on the three-point suspension of a tractor, a transverse, rotatable main shaft mounted horizontally in bearings on the framework, one or more parallel cutting wheels unpivotably mounted on the main shaft but displaceable to the side thereon, whereby .each cutting wheel comprises a plurality of cutting shovels circumferentially mounted at the cutting wheel, as well as power-drive means such as pinions, V-belt drives or the like means capable of transferring movement from the power take-off of the tractor to a rotation of said main shaft with cutting wheels, said apparatus furthermore comprising two supporting wheels adjustable in height and fixedly con¬ nected to the framework, and at least one scraper situated behind each cutting wheel, and a gravel spreader situated above the cutting wheels and known per se and of the type comprising a flat-bottomed, box-shaped container with a conveyor belt conveying the gravel to the rear so as to be released above a releasing roller situated transverse to the moving direction and driven by the power transferring means, whereby a hopperunit is mounted on the gravel spreader and opens on to a horizontally and vertically movable, jointed double hopper associated with each cutting wheel, as well as a detachable screening located about the cutting wheels and the power transferring means, said framework with the parts mounted thereon being capable of being raised and lowered in such a manner that the cutting wheels, the scrapers, the hoppers, and the supporting wheels are raised above the ground, or in such a manner that the cutting wheels, the scrapers, and the hoppers are lowered into said ground while the supporting wheels rest on the surface of the ground. This apparatus is simple and inexpensive to manufacture and it is easy to operate. In addition it is possible in a quick and reliable manner to carry out a cutting up of one or more narrow trenches at a desired interval and of a depth adjustable in response to the existing perme-ability of the ground in question, and furthermore it is possible simultaneously to fill the trenches with the porous material.

According to a preferred embodiment of the apparatus ac¬ cording to the invention, the cutting wheels are disc- shaped and each made of a circular iron plate provided with a hole in the middle, where -the iron plate is bolted on a bushing displaceable on the main shaft, but which is pre¬ vented in a manner known per se from turning relative to said main shaft, and the cutting shovels comprise a plane location part bolted fixedly onto the iron plate at the peripheral rim thereof, and a curved part substantially formed as an obliquely cut, half shell of a truncated cone, the symmetric line of which is in the plane ,of the cutting wheel, and which is mounted with its wide end facing for- ward in the direction of rotation of the cutting wheel.

Both the disc-shaped wheel and the cutting shovels mounted thereon are simple and inexpensive to manufacture, and the shovels are easy to replace when worne out or damaged by for instance stones, as well as they run very satisfactori- ly under all circumstances.

OM The apparatus according to the invention is both simple to manufacture and reliable in use when the power transferring means are driven from the rear power take-off of the trac¬ tor, and they comprise a longitudinal shaft extending to the rear from the power take-off and driving an angular gear situated in the middle of the framework, and a V-belt drive transferring the movement of the angular gear to the main shaft.

A particularly reliable embodiment of the apparatus accord- ing to the invention is obtained when the supporting wheels are mounted on the lower end of their respective arm, the upper end of which is suspended on a bolt through long--^* - itudinal girders in the framework, and these arms may be secured in various angular positions relative to the girders by being secured by means of bolts to their re¬ spective downward girder fixedly connected to the longitu¬ dinal girder behind the suspension points of the arms.

A particularly good levelling of the bottom and the sides of the trenches cut up is according to the invention ob- tained when the adjustable scrapers are mounted on and displaceable along a transverse girder rigidly connected with the longitudinal girders in the framework, and when the scrapers furthermore are adjustable in height relative to the transverse girder.

A particularly suitable and reliable apparatus for laying the porous material into the trenches is according to the invention obtained when the hopper unit comprises a plate inclining downwards and to the rear and being detachably secured on the gravel spreader below the releasing roller, said plate continuing downwardly into narrowing open part¬ ial hoppers associated with their respective cutting wheel and located behind the scrapers, as well as a movable hopper associated with each partial hopper and loosely hinged to said partial hopper in such a manner

-^S^^E that it can turn in its own plane about a bolt in the bot¬ tom plate of the partial hopper and furthermore so that it can rotate about a pin parallel to the bottom plate in the movable hopper and extending through side parts thereon adjacent the rear rim of the hopper, said pin extending between the side parts of the hopper through the clear of a pipe section, which comprises a side flap provided with a hole and forming the hinge, by means of which the movable hopper can turn in its own plane about the bolt. In this manner the porous material is automatically filled into the trenches behind the scrapers, the movable hoppers be¬ ing lowered into said trenches and guided to the sides of the walls thereof.

According to the invention the movable hopper is secured by means of a chain to a lifting grip pivotably mounted about a hoop on the gravel spreader and capable of being retained in a notch* in a raised position, and the hopper can be raised above the ground at the lifting of the grip and locked in this position. As a result the movable hop- per is not dragged across the ground when the cutting wheels of the apparatus are running without being in con¬ tact with the ground.

Moreover according to the invention, the screening may be formed by several transversly separated screens which can be removed or opened individually, and by a front screen hanging downward such as a rubber cloth. In this manner a particularly easy access to the cutting wheels is ob¬ tained, which is of importance when said wheels are to be displaced on the main shaft or when the cutting shovels are to be replaced. Furthermore a particularly good pro¬ tection of the power transferring means against smudging from the ground cut up is obtained, said ground simulta¬ neously being stopped and further divided into fine par¬ ticles by the rubber cloth mounted thereon. In addition it turned out to be advantageous when the cutting wheels are of a diameter of between 80 and 150 cm, preferably about 100 cm, and when the cutting shovels pos¬ sess a maximum operational width of between 3 and 10 cm, preferably about 4 cm.

The feature that the apparatus according to the invention may be lowered to an efficient operational depth of up to about 50 cm, preferably up to about 35 cm, implies that satisfactory results are obtained even under the almost extreme conditions with heavy amounts of rain and a poor permeability in the ground.

Brief Description of Drawings

The invention will be described below with reference to the accompanying drawing, in which

Fig. 1 is a diagrammatic, rear view of an embodiment of an apparatus according to the invention without scrapers, supporting wheels, gravel spreader, and hopper unit.

Fig. 2 is a side view of the embodiment of Fig. 1 with supporting wheels and scraper,

Fig. 3 is a top view of the embodiment of Fig. 2,

Fig. 4 illustrates on a smaller scale the embodiment of Fig. 2 with gravel spreader and hopper unit mounted thereon.

Fig. 5 is a diagrammatic, top view of the gravel spreader and hopper unit of Fig. 4,

Figs. 6 and 6a are a side view of a scraper according to the invention and a top sectional view thereof, respective¬ ly, taken along the line A-A, and Fig. 7 illustrates the hinge connecting the movable hopper with the partial hopper according to the invention.

Best Mode of Carrying out the Invention

Figs. 1, 2 and 3 are diagrammatic views of an apparatus according to the invention without gravel spreader and hop¬ per unit. This apparatus comprises a framework 1 includ¬ ing means 2 rendering it possible to suspend the apparatus on the three-point suspension of a tractor. Bearing brackets 3 are provided on the framework 1, and a trans- verse, horizontal, rotatable main shaft 4 is mounted in said bearing brackets. One or more parallel cutting wheels 5 are unpivotably mounted on this main shaft in such a manner that they are displaceable to the side of said main shaft 4. " Each cutting wheel comprises eight cutting shovels 6 mounted at the peripheral rim of the cutting wheel. The main shaft 4 with the cutting wheels 5 are driven by power transferring means 7 from the rear power take-off of the tractor through a longitudinal shaft 28 and an angular gear 29 diagrammatically shown in Fig. 1. The angular gear 29 communicates with a pulley 30 associat¬ ed with a V-belt drive. This V-belt drive comprises in addition a pulley 31 on the main shaft 4, V-belts 32 and a belt tightener 33. In this manner the cutting wheel 5 may be driven in the direction indicated by the arrow 27 in Fig. 2. The framework 1 comprises some longidutinal girders 44 and transverse girders, and furthermore a scraper 12 associated with each cutting wheel, two support- ing wheels 11, and a screen 20. The supporting wheels 11 are mounted on the lower end 40 of their respective arm 41, the upper end 42 of which is hinged by means of a bolt 43 to the longitudinal girder 44. This upper end 42 can be retained under various angles with the girder 44 by being locked by means of a bolt 45 through the central area of the arm 41 in various heights on a girder 46 hanging down- wards and secured to the longitudinal girder 44 behind the suspension point 43 of the arm 41. The scrapers 12 are mounted on the rear transverse girder 50 of the framework and are displaceable thereon in such a manner that they can be located in the same plane as the cutting wheels 5. The screen 20 is divided into three screens 70, 71, and 72 screening the cutting wheels and the power transferring means, respectively, and protecting the latter against smudging from the ground cut up by the cutting wheels. The cutting wheels 5 are disc-shaped and each cutting wheel is made of a circular iron plate 21 provided with a hole 22 in the middle. The iron plate is bolted on a bushing 23 which is displaceable on the main sha t 4, but which is prevented from turning relative to said main shaft. The cutting shovels 6 comprise a plane location part 25 bolted on the iron plate at its peripheral rim, and a curved part 26 shaped as an obliquely cut half shell of a truncated cone. The symmetric line of this shell is situated in the plane of the cutting wheel, and the shell is mounted with its wide end facing forwards in the direction 27 of rota- tion of the cutting wheel. The framework 1 with the parts mounted thereon can be raised in such a manner that said parts do not touch the ground, or be lowered in such a manner that the cutting wheel and the scraper are lowered into the ground and the supporting wheel rests on the sur- face of the ground.

In operation, the apparatus is dragged by a tractor in the direction to the right of Fig. 2. When the cutting wheels 5 are made rotating in the direction of the arrow 27, the framework 1 with the apparatus is simultaneously lowered in such a manner that the cutting wheels 5 with the shovels 6 and the scraper 12 mounted therebehind are lowered into the ground until the supporting wheels 11 rest on the surface of said ground and consequently determine the operational depth of the cutting wheels and the scrapers. By raising and lowering the supporting wheels

11 on the girder 46, the operational depth is thus adjust- able. During the tractor's pulling forward of the frame¬ work 1 with the entire apparatus and its rotation of the cutting wheels 5, these wheels cut narrow trenches in the ground, said trenches being equalized and smoothened by the scrapers 12.

Fig. 4 illustrates on a smaller scale the apparatus of Fig. 2 with a gravel spreader 13 and an associated hopper unit 15 mounted above and behind, repsectively, said appa¬ ratus, whereby the hopper unit is located bwtween two sup- porting wheels 11. The gravel spreader 13 with the associ¬ ated hopper unit 15 may, however, also be shaped as a sepa¬ rate apparatus suspended on its own framework with support¬ ing wheels and for suspension on the three-point suspension of a tractor.

Fig. 5 is a top view of the gravel spreader and the hopper unit of Fig. 4. The gravel spreader 13 is conventional per se and comprises a flat-bottomed, box-shaped container 14 with a. conveyor belt conveying the gravel to the rear for releasing above and releasing roller transversely situated relative to the moving direction and driven by the power transferring means. The releasing of the gravel is carried out by the gravel falling at an even flow in the entire width of the releasing roller further into the hopper uni 15. This hopper unit comprises a downwardly and rearwardly inclining plate 51 detachably secured on the gravel spreader 13 under the releasing roller. This plate continues into downwardly narrowing open partial hoppers 52 associated with their^' respective cutting wheel and situated behind the scrapers. Subsequently, the gravel slides into a movable hopper 53 secured on each partial hopper, said movable hopper being loosely hinged to the partial hopper in such a manner that it can rotate in its own plane about a bolt 54 in the bottom plate 55 of the partial hopper, and furthermore in such a manner that it can swing about a pin 56 parallel to the bottom plate 57 in the movable hopper. The pin 56 extends through the side parts 58 on the movable hopper adjacent the rear rim 59 thereof, and between the side parts 58 said pin 56 ex¬ tends through a pipe section 60 comprising a side flap 62 with a hole 61. The pin 56, the pipe section 60, and the side flap 62 form the hinge permitting the movable hopper to rotate in its own plane and to swing in a plane perpen¬ dicular thereto. The movable hoppers comprise an elongated narrow orifice insertable into the upper part of the trenches cut up and guidable by the side walls of the trenches during the pulling forward of the gravel spreader. The conveyor belt and rollers of the gravel spreader are driven by the tractor's rear power take-off through the power transferring means 7. During operation of the gravel spreader, the gravel is thus made falling through the hop¬ pers 52 and 53 and consequently into the trench cut up. The amount of dropped gravel is adjustable by adjusting the dosing of the releasing rollers.

When the gravel spreader is to be transported across the field without dropping gravel, the releasing rollers can be stopped and the lowermost end of the movable hopper 53 can be raised by means of a chain 65. The upper end of this chain is secured to a lifting grip 66. pivotably mount¬ ed about a hoop 67 on the gravel spreader and retainable in a notch 68 in the hoop in a raised position in such a manner that the hopper at the lifting of the grip is raised above the ground and locked in this position. When the gravel spreader is not operated, the movable hopper 53 or the entire hopper unit 15 can be removed, and the gravel spreader may optionally be used for other purposes.

As illustrated in Figs. 6 and 6a the scrapers comprise two flat bars welded together perpendicular to each other, one flat bar being curved forwards at the bottom and there supported by a pipe section welded onto the second flat bar. Under normal operational conditions the apparatus is pulled forward at a velocity of between 2 and 4 km/hour, and the cutting wheels rotate at a velocity of about 180 rotations/min. At this velocity the apparatus shown in the drawing produces two trenches simultaneously of a depth of 30 cm, whereby the width of the trenches corresponding to the shovel width is 4 cm. The dropping of gravel may as mentioned be carried out in the same operation or separate¬ ly by means of another tractor, said second tractor then being capable of pulling the drag net too for dividing the ground cut up into fine particles and distributing said ground across the trenches and therebetween.

The shaping of the invention may besides be varied in. numerous ways without thereby deviating from the scope of the invention.

Oϊ.π-1

Claims

Claims :

1. A method of permanently improving the surface drainage from ground fields, preferably grass-covered fields, especially playing fields, lawns and the like fields, c h a r a c t e r i s e d by cutting a network of narrow and substantially vertical trenches in the grass- covered ground, the depth and mutual distance of said ^'■: trenches depending on the permeability of the ground, and by subsequently filling the trenches with a porous material whereafter the ground cut up is divided into fine particles and distributed across the trenches and^' in the spaces therebetween.

2. A method as claimed in claim 1, c h a r a c t e r¬ i s e d by the trenches being positioned substantially parallel to each other and only in one direction and at regular intervals of between about 40 cm and about 200 cm, preferably between about 60 and about 120 cm.

3. A method as claimed in claim 1 or 2, c h a r ¬ a c t e r i s e d by the trenches being cut in a width of between 3 cm and 10 cm, preferably about 4 cm, and at a depth of up to 40 cm, preferably between 10 and 30 cm.

4. A method as claimed in one or more of the preceding claims 1 to 3, c h a r a c t e r i s e d by condensing the porous material during and/or after the filling there- of into the trench.

5. A method as claimed in one or more of the preceding claims 1 to 4, c h a r a c t e r i s e d by coating the surface of the filled trench with a thin, preferably re¬ inforced strip of grass mat and pressing said mat into the trench prior to the distribution of the ground cut up.

r oMPi

6. An apparatus for use when carrying out the method according to one or more of the preceding claims 1 to 5, c h a r a c t e r i s e d in that it comprises a framework (1) including means (2) for its suspension on the three- point suspension of a tractor, a transverse, rotatable main shaft (4) mounted horizontally in bearings (3) on the frame¬ work, one or more parallel cutting wheels (5) unpivotably mounted on the main shaft but displaceable to the side thereon, whereby each cutting wheel comprises a plurality of cutting shovels (6) cirσumferentially mounted at the cutting wheel, as well as power-drive means (7) such as pinions, V—belt drives or the like means capable of trans¬ ferring movement from the power take-off of the tractor to a rotation of said main shaft with cutting wheels, said apparatus furthermore comprising two supporting wheels (11) adjustable in height and fixedly connected to the frame¬ work, and at least one scraper (12) situated behind each cutting wheel, and a gravel spreader (13) situated above the cutting wheels and known per se and of the type com-. prising a flat-bottomed, box-shaped container (14) with a conveyor belt conveying the gravel to the rear so as to be released above a releasing roller situated transverse to the moving direction and driven by the power transferring means (7) , whereby a hopper unit (15) is mounted on the gravel spreader and opens on to a horizontally and vertical¬ ly movable, jointed double hopper (16) associated with each cutting wheel, as well as a detachable screening (20) located about the cutting wheels and the power transferring means, said framework with the parts mounted thereon being capable of being raised and lowered in such a manner that the cutting wheels, the scrapers, the hoppers, and the supporting wheels are raised above the ground, or in such a manner that the cutting wheels, the scrapers, and the hoppers are lowered into said ground while the supporting wheels rest on the surface of the ground.

7. An apparatus as claimed in claim 6, c h a r a c t ¬ e r i s d in that the cutting wheels (5) are disc-shaped and each made of a circular iron plate (21) provided with a hole (22) in the middle, where the iron plate is bolted on. a bushing (23) displaceable on the main shaft (4) , but which is prevented in a manner known per se from turning relative to said main shaft, and that the cutting shovels

(6) comprise a plane location part (25) bolted fixedly onto the iron plate at the peripheral rim thereof, and a curved part (26) substantially formed as an obliquely cut, half shell of a truncated cone, the symmetric line of which is in the plane of the cutting wheel, and which is mounted L with its wide end facing forward in the direction of rota¬ tion (27) of the cutting wheel.

8. An apparatus as claimed in claim 6 of 7, c h a r ¬ a c t e r i s e d in that the power transferring means

(7) are driven by the rear power take-off of the tractor

. -1 and comprise a longitudinal shaft (28) extending to the rear from the power take-off and driving an angular gear (29) situated in the middle of the framework, and a V-belt drive (30, 31, 32, 33) transferring the movement of the angular gear (29) to the main shaft (4).

9. An apparatus as claimed in one or more of the pre¬ ceding claims 6 to 8, c h a r a c t e r i s e d in that the supporting wheels (11) are mounted on the lower end (40) of their respective arm (41) , the upper end (42) of which is suspended on a bolt (43) through longitudinal girders (44) in the framework (1) , and that these arms may be secured in various angular positions relative to the girders (44) by being secured by means of bolts (45) to their respective downward girder (46) fixedly connected to the longitudinal girder behind the suspension points of the arms.

OM

10. An apparatus as claimed in one or more of the pre¬ ceding claims 6 to 9, c h a r a c t e r i s e d in that the adjustable scrapers (12) are mounted on and displace¬ able along a transverse girder (50) rigidly connected with the longitudinal girders (44) in the framework (1) , and that the scrapers (12) furthermore are adjustable in height relative to the transverse girder (50) .

11. An apparatus as claimed in one or more of the pre¬ ceding claims 6 to 10, c h a r a c t e r i s e d in that the hopper unit (15) comprises a plate (51) inclining down¬ wards and to the rear and being detachably secured on the gravel spreader (13) below the releasing roller, said plate continuing downwardly into narrowing open partial hoppers

(52) associated with their respective cutting wheels and located behind the scrapers, as well as a movable hopper

(53) associated with each partial hopper and loosely hinged to said partial hopper in such a manner that it can turn in its own plane about a.bolt (54) in the bottom plate (55) of the partial hopper and furthermore so that it can rotate about a pin (56) parallel to the bottom plate (57) in the movable hopper and extending through side parts (58) there¬ on adjacent the rear rim (59) of the hopper, said pin ex¬ tending between the side parts of the hopper through the clear of a pipe section (60) , which comprises a side flap (62) provided with a hole (61) and forming the hinge, by means of which the movable hopper can turn in its own plane about the bolt (54) .

12. An apparatus as claimed in claim 11, c h a r ¬ a c t e r i s e d in that the movable hopper (15) is se- cured by means of a chain (65) to a lifting grip (66) pivotably mounted about a hoop (67) on the gravel spreader and capable of being retained in a notch in a raised posi¬ tion, that the hopper can be raised above the ground at the lifting of the grip and locked in this position.

13. An apparatus as claimed in one or more of the pre¬ ceding claims 6 to 12, c h a r a c t e r i s e d in that the screening (20) is formed by several transversely sepa¬ rated screens (70, 71, 72) which can be removed or opened individually, and by a front screen hanging downward, such as a rubber cloth (73) .

14. An apparatus as claimed in one or more of the pre¬ ceding claims 6 to 13, c h a r a c t e r i s e d in that the cutting wheels (5) are of a diameter of between 80 and 150 cm, preferably about 100 cm, and that the cutting shovels (6) possess a maximum operational width of between 3 and 10 cm, preferably about 4 cm.

15. An apparatus as claimed in one or more of the pre¬ ceding claims ^'6 to 14, c h a r a c t e r i s e d in that the apparatus can be lowered to an efficient operational •depth of up to 50 cm, preferably up to about 35 cm.

OMPI