GB2058533A

GB2058533A - Spreader

Info

Publication number: GB2058533A
Application number: GB8028429A
Authority: GB
Original assignee: C Van der Lely NV
Current assignee: C Van der Lely NV
Priority date: 1979-09-10
Filing date: 1980-09-03
Publication date: 1981-04-15
Also published as: DE3033666C2; NL178645B; NL187223C; GB2058533B; DE3050904C2; FR2464629A1; NL7906726A; NL187223B; NL8500757A; FR2464629B1; DE3033666A1; NL178645C

Abstract

A spreader, for example for agricultural fertilizers, comprises a distributing member (10). Measuring means (16) are provided for providing an indication of the height of the distributing member (10) above the ground, and of its orientation, so that these parameters can be set accurately to obtain a desired spreading distance. The measuring means may include detectors 69 which are sensitive to impingement of the material discharged to establish the direction of discharge of the material. <IMAGE>

Description

SPECIFICATION A spreader This invention relates to a spreader.

Acording to one aspect of the present invention there is provided a spreader comprising a frame and a distributing member, the spreader including measuring means for providing an indication of the disposition of the distributing member with respect to the surface to which material is to be supplied by the spreader.

The measuring means may comprise members by which the orientation of the dstributing member with respectto the surface to be covered can be determined. The measuring means may comprise two spaced distance measuring members by means of which the height of spaced parts of the dispenser above the ground can be measured.

An advantageous construction is obtained if a distance measuring member or its projection passes substantially through a coupling location at which the spreader may be coupled with the lower lifting arms of the lifting device of, for example, a tractor.

When the spreader is tilted with respect to the lifting device, the distance measuring member will not significantly change its position.

The measuring members may be displaceably mounted on the frame of the spreader. With this construction the measuring means can be set with respect to the surface to be covered, after which the device can be changed in position relative to the surface to be covered without affecting the measuring means so that the adjustment can be readily carried out and assessed.

According to an other aspect of the present invention there is provided a spreader comprising a frame and a distributing member, the spreader including measuring means for providing an indication of the disposition of the distributing member with respect to the surface to which material itto be supplied by the spreader, the measuring means comprising at least one upwardly extending detector which is positionable in the path of material discharged by the spreader during operation, the detector being adapted to indicate the position, with respect to the vertical direction, at which material strikes the detector.

Such a construction enables the direction of discharge of the material to be assessed, which provides an indication of the distance over which the material will be thrown.

Advantageously, the detector is substanially perpendicular to the surface to be covered. The position of the detector relative to the surface may be maintained by mounting the detector on a ground support, which is pivotally connected with the rest of the spreader.

The direction of distribution of the material can be very accurately set when two detectors are arranged at a distance from one another in the direction of ejection of the material.

With constuctions in accordance with the present invention, the disposition of the distributing member can be set easily to provide an accurate distribution pattern.

For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a side view of a spreader; Figure 2 is a side view of another spreader; Figure 3 is a side view of another spreader; Figure 4 is a side view of another spreader; Figure 5 is a side view part of another spreader; Figure 6 is a side view of another spreader; and Figure 7 is a schematic plan view of a spreader.

Figure 1 shows a spreader 1 for broadcasting granular and/or powdery material, such as agricultural fertilizers. The spreader 1 is shown coupled with the lifting device 2 of a tractor 3. The spreader 1 comprises a frame 4 provided with coupling locations 5 and 6 fastened to the lower arms 7 and the top rod 8 respectively of the lifting device 2. A hopper 9 is mounted on the frame 4, and beneath the hopper 9 there is a distributing member 10 which is adapted to rotate about an upwardly extending rotary shaft 14.

The distribution member 10 is drivable through a gearbox 11, which is illustrated as being coupled by an auxiliary shaft 12 to the powertake-offshaft of the tractor 3. Between the distribution member 10 and the hopper 9 there is a dosing mechanism 13 for controlling the feed rate of material from the hopper to the distribution member.

The spreader is provided with measuring means 16 which enables the height of the distribution member 10 above the ground to be measured and adjusted. The measuring means 16 also enables adjustment of the orientation of the distribution member with respect to the ground surface 15.

The measuring means 16 comprises a supporting rod 17, which is horizontal when the distribution member 10 is horizontal and which is fastened by plates 18 and 19 to the frame 4. The ends of the supporting rod 17 are connected by pivotal joints 21 and 23 with distance measuring members 20 and 22.

The member 22 is located behind the member 20, with respect to the direction of travel 32 of the spreader in operation. The distance measuring member 20 comprises a tube 29 in which a rod 24 can be displaced and fixed by a locking member 24 in any one of a plurality of positions. The distance measuring member 22 comprises a bar 30, the lower end of which is provided with a pointed part 26. The part 26 comprises a plurality of links 27, which are pivoted to one another by pivots 28 so that they can be folded together.

In use, the spreader is hitched to the lifting device 2 as is shown in Figure 1. The hopper 9 is filled with the material to be broadcast, for example granular fertilizer. The dosing mechanism 13 (not shown in detail) is set to establish the desired flow rate of material from the hopper to the distributing member 10. The distributing member 10 is driven from the power take-off shaft through the auxiliary shaft 12 and the transmission in the gearbox 11. For a given shape and size of distributing member and for a given speed of rotation, the material fed from the hopper to the distributing member is thrown a dis tance which depends upon the height of the dis tributing member 10 above the surface 15 to be covered and the orientation of the distributing member 10 relative to that surface.In the normal working position the distributing member 10 will be parallel to the ground 15, i.e. the rotary shaft 14 is perpendicularto the ground 15. The height of the distributing member 10 above the ground is then about 60cms. With these parameters, the material is spread over a strip about 16 meters wide during a run of the spreader, the material being thrown about 8 metres by the distribution member. The distance which the material is thrown and hence the width of the strip covered during a run of the spreader in the direction of the arrow 32 can be changed by chang ing the position of the distributing member with respect to the ground so that the distributing member is at a different angle to the ground. The distance can also be changed by altering the height of the distributing member above the ground.

The measuring means 16 enables the position of the distributing memberto be adjusted in the desired mannerto obtain the required spread. Using the measuring means 16 as shown in Figure 1, the position of the distributing member is set at the beginning of the job. Figure 1 shows the position in which the distance measuring members 20 and 21 are at right angles to the carrying rod 17 and are perpendiculartothe ground surface 15. In the position shown the distributing member 16 is at a height 33 of 60 cms above the ground. This distance may be reduced by sliding the lower rod 24 further into the tube 29 and folding a link 27 of the part 26 of the distance measuring member 22. The rod 24 may be provided with a scale so that the height of the dis tributing member can be read.

The rod 24 may have such a length that the desired variation of the height 33 can be attained. Each link 27 may have a length of 4 to 5 cms so that the height 33 can be adjusted by corresponding intervals. If it is desired to incline the distributing member to the horizontal, as is indicated in broken lines in Figure 1, one or more links can be folded out from the part 26.

The length of each link may be such that folding out of one linkcorrespondsto an angular change of the distributing member relative to the ground of about 2.5 . In the position indicated by broken lines in Fig ure 1, the distributing member 10 is at an angle of about 100 to the ground surface 15. Thus the distance measuring member 22 is lengthened by an amount 31 by folding out four links 27. The angle 34 of the distributing member can then be readily set by adjusting the top rod 8 to an extent such that the whole spreader tilts about the axis of the connection of the dispenser with the lower arms 7.This tilting is continued until the lower ends of the distance measuring member 20 and ofthe extended distance measuring member 22 are just in contact with the ground.

Most of the material fed through outlet ports of the dosing mechanism eccentrically with respect to the rotary shaft 14to the distributing member 10 is thrown rearwardly with respect to the direction 32.

When the distribution member is in the position indicated by broken lines in Figure 1,the material is thrown obliquely upwards to the rear, and can be thrown over a larger distance from the distributing member than when the distributing member is parallel to the ground surface 15. If it is desired to set the distributing member 10 so that it slopes downwardly from front to rear, more links 27 of the distance measuring member 22 can be folded up out of the position indicated by full lines in Figure 1,the desired inclined position of the distributing member again being established when the distance measuring members 22 and 20 are just in contact with the ground.

The distance measuring member 20 is located substantially beneath the axis of the coupling iocations 5. Since the height of this axis will not change significantly when the spreader is tilted by adjusting the length of the top rod 8, the distance measuring member 20 need not be adjusted when the spreader is merely tilted. In order to set a tilted position of the distributing member most accurately, the distance 35 between the distance measuring members 20 and 22 is largerthan the greatest diameter 36 of the distributing member.

When the spreader has been set in its desired position by putting the axis of the locations 5 at the desired height by adjusting the lower lifting arms 7 and by appropriately adjusting the length of the top rod 8, the distance measuring members 20 and 22 can be put into a rest position. For this, the measuring members 20 and 22 swing about the axes of the joints 21 and 23, until they are parallel to the rod 17.

In order to hold the distance measuring members 20 and 22 in this rest position, the carrying rod 17 may be provided with hooks for retaining the members 20 and 22. The plates 18 and 19 by which the carrying rod 17 is secured to the frame 4 may be provided with supports for the members 20 and 22. The plates 18 and 19 may be designed so that the measuring means 16 is releasably connected with the frame 4.

The measuring means 16may then be removed from the spreader so that the spreader can be used withoutthe measuring means, or so that the measuring means can be mounted on another machine, such as another spreader.

Figure 2 shows a spreader which is the same as that of Figure 1, with the exception of the measuring means, here designated 41. The measuring means 41 is connected to the frame 4 of the spreader 1 so as to be pivotable. The measuring means 41 has a mounting bush 42,which is pivotable about the pin which connects the spreadertothe lower lifting arms 7 of the tractor at one of the coupling locations 5. Alternatively, the bush 42 may be mounted on a pin aligned with the connecting pin. The bush 42 is provided with distance measuring members 43 and 44. The member 43 comprises a rod 45 with a scale, and a tube 46 which is slidable on the lower end of the rod 45. The tube 46 has a foot 47 and can be fixed by a pin 48 in different positions along the rod 45.

The member 44 comprises a rod 49 which is inclined to the ground 15, this rod 49 having a tubular lower end 50, in which a rod 51 is slidable. The rod 51 can be fixed in any one of a plurality of positions by a locking pin 52. The rod 51 has a foot 53 at the lower end. The measuring means 41 further comprises a pointer 54, connected to the bush 42, and a plate 55, provided with a scale 56, fixed to the frame 4.

In this embodiment the normal top rod is replaced by a hydraulic top rod 57, which can be shortened or lengthened by means of a hydraulic mechanism from the seat of the tractor.

To use the measuring means 41, the lengths of the distance measuring members 43 and 44 are adjusted to establish the desired height of the distributing member above the ground 15. The tube 46 and the rod 51 can be fixed in their desired positions by means of the pins 48 and 52. When the lengths of the members 43 and 44 are fixed and the two feet 47 and 43 bear on the ground, the point 5 is at the desired height above the ground. The length of the top rod 57 is then adjusted, causing the plate 55 to turn, with the spreader, about the axis 5, either until the pointer is atthe zero point of the scale 56, corresponding to the distributing member 10 being parallel to the ground 15, or until the pointer 54 is at a point on the scale corresponding to a desired inclination of the distributing member 10.When the top rod 57 is, for example, shortened, the spreader will turn to the left in the direction of the arrow 58 about the pin at the location 5. The distributing member 10 will then be at an angle to the ground 15, with the distributing member sloping upwardly from front to rear. Thus the position of the distributing member, and of the entire spreader indicated by broken lines in Figure 2 can be obtained. When the spreader turns about the pin at the location 5, the plate 55 moves along the pointer 54. The scale 56 thus provides an indication of the movement of the plate relative to the pointer, and the angle of inclination of the distributing member 10 with respect to the surface 15 is indicated.The inclined position of the spreader can be readily obtained from the tractor seat, using the means shown in Figure 2, by hydraulically actuating the top rod 57, because the pointer 51 and the scale 56 are located within the field of view of the driver on the tractor seat.

The measuring means 41 and 16 can be used for adjusting the height of the distributing member and its inclination relative to the ground surface over which the material is to be spread, irrespective of whether the distributing member and the ground surface are horizontal or inclined.

Figure 3 shows the spreader 1 with another form of measuring means, here designated 61. The measuring means 61 of Figure 3 is pivotally connected to the frame 4, and comprises a horizontal carrying rod 62, to which distance measuring members 63 and 64 are fastened. The distance measuring members each comprise slidable lower ends 65 and 66, each of which has a scale and is fixable in a plurality of positions by means of pins 71. At the front end of the rod 62, in line with the distance measuring member 63, there is a coupling rod 67 which is provided at its top end with a mounting bush 68, which is pivotable about the pin at the location 5. If desired, a further pin may be arranged on the frame 4 in line with the pin 5 for receiving the bush 68.The measuring means 61 furthermore comprises a detector 69, which is connected by leads 70 with an indicator (not shown) near the driver's seat of the tractor 3. The detector69 is connected to the rod 62 near its rear end for movement about a pivotal shaft 72. Pivoting of the detector 69 about the pivotal shaft 72 with respect to the rod 62 can be prevented by means of a locking mechanism (not shown in detail), which enables the detectorto be fixed in a substantially vertical position.

With the measuring means 61 of Figure 3 the height of the distributing member 10 above the surface 15 can be set using the distance measuring members 63 and 64. The parts 65 and 66 of these members can be drawn out to a greater or lesser extend and fixed in place by the locking pins 71 in order to establish the desired height 33. In this embodiment, as in that of Figure 2, the measuring means 61 is pivotable with respect to the frame 4 about the pin at the location 5. When the distributing member 10 is parallel to the surface 15 to be covered and the lower ends of the members 63 and 64 bear on the ground the detector 69 is perpendicular to the ground 15 as is shown in Figure 3. Material thrown by the distributing member initially traveis parallel to the surface 15, leaving the distributing member along the line 73.The material will impinge upon the region 74 of the detector. The detector 69 transln its through the leads 70 a signal indicating the vertical position of the region struck by the material. Thus it is possible to establish the direction in which the material leaves the distributing member 10, since the detector is located at a given height above the ground 15. In this way an indication is obtained of the distance over which the distributing member throws the material. The distance over which the material is thrown can be adjusted by putting the distributing member in an inclined position, such as the position indicated by broken lines in Figure 3.

This position can be obtained by shortening the top rod 57, using the hydraulic mechanism actuated from the driver's seat on the tractor. When tilting of the spreader and hence of the distributing member is carried out during a spreading operation, the path along which material is thrown will move upwards and the material will eventually be thrown in the direction indicated by a broken line 73A in Figure 3, the detector then being struck in the region 75. Since the distance 76 of the detector from the outer circumference of the distributing member is known, the region of the detector struck by the material is indicative of the angle at which the material is thrown, and thus provides a measure of the distance over which the material is thrown. Thus the detector 69 provides an indication of the width over which material is spread during operation of the spreader.

When the correct position of the spreader and hence of the distributing member with respect to the surface 15 has been established, the detector 69 can be tilted down so that it is parallel to the rod 62. The rod 62 can then be fastened to a hook (not shown) on the frame 4 and the rods 65 and 66 can then be retracted so that they do not touch the ground. The device is then ready for use.

In this embodiment the detector 69 is preferably able to indicate the number of grains of material bombarding the detector per unit surface and per unit time. Thus the detector 69 can provide an indica tion of the rate of distribtution of material in relation to the distance of spread and the width over which the material is spread during travel of the spreader.

The indicator can thus provide the tractor driver with an indication of the correct setting of the dosing member and of the distance of spread of the material. The setting of the distance of spread of the material can be readily varied from the tractor seat by changing the length of the top rod 57.

Figure 4 shows an embodiment in which measuring means, here designated 81, is pivoted about a pivot 97 to the hopper 9 of the spreader 1. The measuring means 81 comprises a carrying rod 82, which is pivotally connected with the hopper and to which a ground support 83 is rigidly secured. Two detectors 84, 85 are connected to the carrying rod 82 for pivotal movement about shafts 87,88. The detectors 84 and 85 are spaced apart by a distance 86 in the intended direction of travel of the spreader. The detectors 84 and 85 are offset laterally from each other so that the detector 84 located nearer the distributing member 10 does not block the flow of material to the detector 85. The support 83 is located directly behind the detector 84 so that it too does not block the flow of material to the detector 85.Locking mechanisms 90 are provided near the shafts 87 and 88 to permit the detectors 84 and 85 to be locked in place with respect to the rod 82. The ground support 83 comprises at the lower end a foot 91 which is curved to the rearwith respect to the intended direction of travel 32. The foot 91 supports the measuring means 81 on the ground during operation. The length of the support 83 is adjustable to set the desired height of the distributing member above the ground 15. A rope 89 is connected to the rod 82 so that, if desired, the measuring means 81 can be tilted upwards about its pivotal connection with the hopper 9 by pulling the rope 89.

For use, the measuring means 81 is arranged as is shown in Figure 4, with the support 83 bearing on the ground and the rope 89 being slack. At the beginning ofthe spreading operation or while stationary before starting work, the material is thrown against the detectors 84 and 85. When the distributing member 10 is in a horizontal position at a height 33 above the ground, the material will strike the regions 92 of the detectors, which are the same height above the ground as each other. The detectors 84 and 85 transmit through the leads 70 a signal to an indicator near, for example, the driver's seat of the tractor, this signal corresponding to the heights at which the detectors are struck.When the material strikes the detectors in the regions 92, this indicates that the material is thrown horizontally, and that the distributing member 10 is parallel to the surface 15.

The spreader may be tilted, for example by shortening the top rod 57, to place the distributing member in the position indicated by broken lines in Figure 4.

In this position the material is thrown along the line 93, the detector 84 then being struck in the region 94 and the detector 85 in the region 95. The region 95 is higher above the ground than the region 94. The lower ends of the detectors 84 and 85 are the same height as each other above the ground 15. The difference in height of the points of impact on the detectors provides an indication of the angle at which the material leaves the distributing member and hence of he orientation of the distributing member 10 relative to the ground 15. As stated in the preceding embodiments, the angle at which the material is thrown, with respect to the ground su rface, determines the distance over which the material is spread. The two detectors 84 and 85 thus provide an indication of the spreading distance of the material.

The distance 86 will preferably have a value such that it is easy to ascertain the difference between the heights at which the material impinges on the detectors 84 and 85 and hence the angle of discharge of the material. Also, the distance 86 must be selected to be structurally most advantageous. The distance 96 of the first detector 84 from the distributing member may be relatively small. In the illustrated embodiment, the distance 86 is about 40 cms and the distance 96 about 60 cms.

When the spreader is used on horizontal ground, the detectors 84 and 85 can be allowed to swing freely from the shafts 87 and 88, so that they are in a perpendicular position. When the spreader makes a trial run, the detectors 84 and 85 are preferably fixed relatively to the carrying rod 82 by the locking mechanisms 90. When the spreader is on an inclined surface, the detectors again can swing freely, to occupy a position perpendicular to the surface 15. In this position the detectors can be fixed in place by the locking mechanisms 90. With the detectors fixed in this position, and when the distributing member 10 is parallel to the ground, the material will strike the detectors in the regions 92, from which it can be inferred that the distribution member is parallel to the surface 15 to be covered.

When the desired position of the spreader relative to the tractor has been fixed, the measuring means 8 can be moved out of the spreading path by lifting it about the pivotal connection between it and the hopper 9. To do this, the rope 89 is pulled. The rope 89 can be made fast with the measuring means elevated so that the measuring means are located above the path of the material discharged by the distributing member, the distribution of material thus not being hindered or adversely affected by the measuring means. If the lower end of the support 83 should remain in the path of the material, the distribution will not be seriously affected, since the support 83 has only a small width.

Figure 5 shows an embodiment in which the measuring means, here designated 101, issimilarto that of Figure 4. The measuring means 101 comprises a carrying rod 102, which is connected with the hopper 9 for pivotal movement about a shaft 103.

The carrying rod 102 is provided at the rear end with a support 104 of variable length having a foot 105.

Near the end of the rod 102, and in front of the support 104, there is a detector 106, which is pivotable with respect to the rod 102 about a shaft 107. The position of the detector 106 with respect to the rod 102 can be fixed by means of a locking mechanism 108 near the pivotal shaft 107. The detector 106 is at a distance 109 from the distributing member, this distance 109 being larger than the distance of the detectors 84 and 85 from the distributing member in the embodiment of Figure 4. A rope 110 is connected to the carrying rod 102.

When the measuring means of Figure 5 is used, it is freely pivotable about the shaft 103, the support 104 bearing on the ground. In this position the height of the detector 106 above the ground surface 15 is set by adjusting the length of the support 104 to suit the desired height of the distributing member 10 above the ground. With the distributing member 10 parallel to the surface 15 and at the desired height, the discharged material will strike the lower region 110 of the detector. The spreader may be set in an inclined position, such that the material is thrown more upwardly, by shortening the top rod 57. The height of the region of the detector struck by the material is indicative of the angle of discharge of the material so that an indication is given of the discharge overwhichthe material is thrown.In a similar manner as described above, an assessment can thus be made of the distance over which the material is spread. As in the preceding embodiments, the detector 106 may be designed to be responsive to the number of grains of material striking the detector per unit surface and per unit time, to provide an indication of the spreading density of the material. Since the distance 109 of the detector 106 from the distributing member 10 is comparatively large, small errors in setting height 33 of the distributing member above the ground will not significantly affect the measurement. The distance 109 is preferably about 150 cms. As in the preceding embodiment, the measuring means 101 can be held out of the path of the material by the rope 110.

Figure 6 shows another embodiment of a spreader provided with measuring means. The spreader shown in Figure 6 is similar two those of the preceding embodiments, but the distributing member 116 is mounted in a different manner. The distributing member 116 is mounted on a shaft 117 which is journalled in a gearbox 118. The distributing member 116 is pivotable with the shaft 117 about a horizontal pivotal shaft 119 with respect to the frame 4. Near the pivotal shaft 119 there is a locking mechanism 120 (not shown in detail) for fixing the distributing member, the shaft 117 and the gearbox 118 in a selected one of a plurality of different positions around the rotary shaft 119.

In this embodiment measuring means 121 are coupled with the rear end of the hopper 9. The measuring means comprises a carrying rod 122, which may be secured to the rear side of the hopper so that during operation the measuring means is immovably coupled with the hopper 9. The measuring means 121 comprises a detector 123, which is connected by leads 70 to an indicator disposed near the tractor driver. The carrying rod 122 and the detector are arranged so that when the distributing member 116 is parallel to the ground 15 the material is thrown in a direction parallel to the ground and strikes the detector in the region 124. The orientation of the distributing member 116 can be adjusted by means of the top rod 57. The height of the distributing member above the ground is adjustable by means of the lower arms 7.

In the horizontal position the discharged material will inmpinge on the detector 123 in the region 124.

From this position the distributing member can be turned about the pivotal shaft 119, for example into a position indicated by broken lines in Figure 6. In this position the material is thrown by the distributing member along the line 125 and the detector is struck in the region 126. The region of impact of the material yields, as in the preceding embodiments, an indication of the direction in which the material is ejected and hence of the distance of spread of the material. Consequently, in this embodiment it is not necessary to tilt the whole spreader, by actuating the top rod 57, to adjust the orientation of the distributing member. This has the advantage that the measuring means can be simply fixed to the frame parts of the spreader.Owing to the fixed position of the detector 123 with respect to the frame 4, a change of position of the distributing member 116 with respect to the frame can be sensed by the detector in the manner described in this embodiment.

When after a trial run the detector is no longer wanted, since the desired position of the distributing member is set, the detector can be readily removed by unhooking the carrying support 122 from the top of the hopper. If desired, the construction of Figure 6 may be modified by making the detector pivotable out of a working position as shown in Figure 6 to a rest position, in which the detector is no longer located in the path of the material.

The various forms of measuring means described herein may be successfully employed with any kind of spreader or broadcaster provided with a distributing member which throws the material more or less vigorously. Although, in all of the embodiments described, the spreaders comprise distributing members mounted for rotation about upwardly extending rotary shafts, the measuring means may also be used with other types of distributing members, for example those adapted to reciprocate about a shaft. The use of the measuring means is particularly successful when the material is thrown by the distributing member mainly in one direction, as in the spreaders shown, where the material is mainly discharged to the rear with respecttothe normal direction of travel.When the detectors are in use, they have to be disposed so that they are invariably located completely in the spreading pattern when the measurements are made. The measuring means may be successfully used in particular in devices in which the material is fed eccentrically of the distributing member so that the material is spread over a given sector around the rotary axis.

Figure 7 shows schematically an embodiment of a spreader 130 having two distributing members 131 and 132 adapted to rotate about upwardly extending rotary shafts. As in the preceding embodiments, the material is fed eccentrically to the distributing members so that the material is spread over a sector 133 by the distributing members. Figure 7 schematically shows that, for example, two measuring means having detectors 134 and 135 respectively are located each approximately at the centre of the spreading sector 133 of each of the distributing members. As an alternative, however, the detectors may be arranged nearer the edges 136 or 138 of the spreading area.It is, however, advantageous to maintain the detectors at a given distance from the edges 136 or 138 in order to carry out a reliable measurement, since the number of grains ejected per unittime near the edges 136 is in general smaller than in the major part of the spreading angle 133. The embodiment shown in Figure 7 has two distributing members, but in devices having one distributing member the detectors are preferably arranged appromimately near the centre of the spreading sector. In spreaders having two distributing members, whose spreading sectors have a large area of overlap, the two measuring means with one or more detectors may be replaced by a single measuring means with one or more detectors. The detector may be arranged at the centre of the device so that, viewed on plan, it is located approximately near the longitudinal line 137.

Whilst various features of the spreaders that have been described, and are illustrated in the drawings, will be set forth in the following claims as inventive features, it is to be noted that the invention is not necessarily limited to these features and that it encompasses all of the features that have been described both individually and in various combinations.

Claims

1. A spreader comprising a frame and a distributing member, the spreader including measuring means for providing an indication of the disposition of the distributing member with respect to the surface to which material is to be supplied by the spreader.

2. A spreader as claimed in claim 1, in which the measuring means is adapted to provide an indication of the orientation of the distributing member with respect to the surface.

3. A spreader as claimed in claim 2, in which the measuring means comprises two distance measuring members which are spaced apart from one another and which are disposed to establish the height of spaced parts of the spreader above the surface.

4. A spreader as claimed in claim 3, in which the two distance measuring members are spaced apart in the intended direction of operative travel of the spreader.

5. A spreader as claimed in claim 3 or 4, in which the distance measuring members are spaced apart by a distance which is not less than the greatest dimension ofthe distributing member.

6. A spreader as claimed in any one of claims 3 to 5, in which the distance measuring members comprise upwardly extending measuring rods, at least one of which has an adjustable length.

7. A spreader as claimed in claim 6, in which the measuring means are vertically displaceable to establish the height of the distributing member above the surface.

8. A spreader as claimed in claim 6 or 7, in which the or each adjustable distance measuring member comprises a plurality of parts, which are relatively movable for adjusting the length of the distance measuring member.

9. A spreader as claimed in claim 8, in which the said parts are pivotable relatively to one another.

10. A spreader as claimed in any one of claims 3 to 9, in which at least one of the distance measuring members or its projection extends substantially through a coupling location of the spreader at which the spreader may be fastened to the lower lifting arms of a lifting device of a vehicle to which the spreader may be hitched.

11. A spreader as claimed in any one of claims 3 to 10, in which the measuring means comprises a substantially horizontal carrying rod secured to the frame of the spreader, the distance measuring members being provided at the ends of the rod.

12. A spreader as claimed in any one of claims 3 to 11, in which the distance measuring members are substantially perpendicular to the surface to be covered.

13. A spreader as claimed in any one of the preceding claims, in which at least part of the measuring means is displaceable relatively to the frame.

14. A spreader as claimed in claim 13, in which the measuring means is displaceable from a working position, for establishing the disposition ofthe distributing member with respect to the surface, to a rest position in which the measuring means is inoperative.

15. A spreader as claimed in claim 13or14, in which at least part of the measuring means is mounted on the frame for pivotal movement about an axis which is at or adjacent a coupling location at which the spreader can be coupled with the lower lifting arms of a lifting device of a vehicle to which the spreader may be hitched.

16. A spreader as claimed in any one of claims 13 to 15, in which those parts of the measuring means which are pivotally connected with the frame cooperate with a further part of the measuring means which is mounted on the frame such that the relative positions of the parts of the measuring means provide an indication of the orientation of the distributing member.

17. A spreader as claimed in claim 16, in which the measuring means comprises a scale and a pointer movable across the scale.

18. A spreader as claimed in claim 17, in which the scale is provided on a part of the measuring means which is rigidly fastened to the frame.

19. A spreader as claimed in any one of claims 13 to 18, in which the part of the measuring means which is displaceable relative to the frame comprises at least one distance measuring member for provide ing an indication of the distance of part of the spreader from the ground.

20. Aspreader as claimed in claim 19, in which the part of the measuring means which is displaceable relative to the frame comprises two distance measuring members, an end of one of which is spaced from an end of the other.

21. A spreader as claimed in claim 19 or 20, in which the length of at least one of the distance measuring members is adjustable.

22. A spreader as claimed in claim 20 or 21, in which one of the distance measuring members extends substantially vertically, and in which the other distance measuring member is inclined to the surface to be covered.

23. A spreader as claimed in any one of the preceding claims, in which the measuring means comprises a detector which is positionable in the path of material discharged by the spreader during operation and which extends upwardly, the detector being adapted to indicate the position, with respect to the vertical direction, at which material impinges on the detector

24.A spreader comprising a frame and a dis- tributing member, the spreader including measuring means for providing an indication of the disposition of the distributing memberwith respecttothe surface to which material is to be supplied by the spreader, the measuring means comprising at least one upwardly extending detector which is positionable in the path of material discharged by the spreader during operation, the detector being adapted to indicate the position, with respect to the vertical direction, at which material strikes the detector.

25. A spreader as claimed in claim 23 or 24, in which the detector is substantially perpendicular to the surface to be covered.

26. A spreader as claimed in any one of claims 23 to 25, in which the detector is displaceable into a position in which it is out of the path of material discharged by the spreader.

27. A spreader as claimed in any one of claims 23 to 26, in which the detector is fastened to a distance measuring member.

28. A spreader as claimed in claim 27, in which the detector is mounted on the distance measuring member for displacement relative to the distance measuring member into an inoperative position.

29. A spreader as claimed in any one of claims 23 to 26, in which the detector is mounted on a ground support, which is pivotally connected with the rest of the spreader.

30. A spreader as claimed in claim 28, in which the length of the ground support is adjustable.

31. A device as claimed in claim 29 or 30, in which an elongate flexible element is connected to the ground support and is adapted to extend to a driver's seat from which the spreader is controlled, whereby the detector can be moved vertically into an inoperative position.

32. A spreader as claimed in any one of claims 23 to 31, in which the detector is one of two detectors which are spaced from one another in the direction of discharge of the material.

33. A spreader as claimed in claim 32, in which the detectors are at the same height.

34. A spreader as claimed in claim 33, in which the detectors are offset from each other in a direction perpendicular to the direction of discharge of the material, whereby each detector is struck by material during operation of the spreader.

35. A spreader as claimed in claim 33 or 34, in which the detectors are spaced apart by a distance of at least about 25 cms.

36. A spreader as claimed in any one of claims 32 to 35, in which both detectors are mounted on a common ground support.

37. A spreader as claimed in any one of claims 33 to 36 in which the or each detector is coupled with a carrier so as to be pivotable about a substantially horizontal pivotal axis.

38. A spreader as claimed in any one of claims 33 to 37, in which the nearer of the two detectors to the distributing member is about 50 cms from the distributing member.

39. A spreader as claimed in any one of claims 23 to 38, in which the detector or one of the detectors is spaced from the distributing member by about 1.50 ms.

40. A spreader as claimed in any one of claims 23 to 39, in which the or each detector is connected with an indicator that can be arranged near a driver's seat from which the spreader is controllable.

41. A spreader as claimed in any one of claims 23 to 40, in which the or each detector is responsive to the rate of impingement of material on the detector, thereby to provide an indication of the amount of material spread per unit area.

42. A spreader as claimed in any one of the preceding claims, in which the orientation of the distributing member is adjustable relative to the frame.

43. A spreader substantially as described herein with reference to and as illustrated in the accompanying drawings.