GB2210431A

GB2210431A - Drive unit for a spraying machine

Info

Publication number: GB2210431A
Application number: GB8821502A
Authority: GB
Inventors: John Sydney Clayton; Peter Robin Hughes
Original assignee: Micron Sprayers Ltd
Current assignee: Micron Sprayers Ltd
Priority date: 1987-09-29
Filing date: 1988-09-14
Publication date: 1989-06-07
Also published as: GB8722794D0; GB8821502D0

Abstract

A drive unit has an angularly movable member (20) with spaced arms (23, 24) carrying a shaft (32), pinions (36, 37) being mounted on the shaft via respective one way clutches (38, 39) and engaging a fixed crown wheel (15), up and down movement of a manually operable handle (47) causing angular movement of said member (20) and the shaft (32) carried by it, the pinions (36, 37) rotating as they move around the crown wheel (15) with one pinion being locked to the shaft and the other pinion freewheeling in each direction of handle movement. The shaft thus rotates and oscillates. The drive unit can be used in a spraying machine, the shaft (32) being arranged to drive a fan (42) to provide an air blast to a rotary atomiser (46). <IMAGE>

Description

DRIVE UNIT This invention relates to a drive unit, and particularly, but not exclusively, to an agricultural spraying machine including such a drive unit.

In the application of crop control products, such as fungicides, r insecticides and foliar feeds, to crops such as bush fruits, coffee beans etc., it is often an advantage to use some form of air movement to improve leaf coverage. It is known to achieve such air movement by means of the use of a machine with a petrol engine. However in certain cases, such a relatively expensive and sophisticated machine cannot be provided.

There is thus a need for a spraying machine having air movement means, in which the means are actuated simply and easily.

The object of the invention is to provide a drive unit which is operable in an easy and efficient manner.

According to the invention there is provided a drive unit comprising a member arranged to be angularly movable about an axis, a rotatable shaft, gear means on the shaft, further gear means engaged with the gear means on the shaft, angular movement of said member in use producing relative movement between the shaft and said further gear means resulting in rotation of the shaft.

Preferably the gear means is at least one pinion and the further gear means is a crown wheel.

Desirably the crown wheel is fixed and the shaft is carried on the member for angular movement therewith, so that when the member is angularly moved, in use, the corresponding angular movement of the shaft causes said at least one pinion to be rotated by its engagement with the fixed crown wheel.

Conveniently said at least one pinion is mounted on the shaft via a one-way clutch, so that the rotation of said at least one pinion is transmitted to the shaft in one direction of angular movement only of the member.

Advantageously the shaft has two pinions mounted thereon via respective one-way clutches, the pinions being engaged with the crown wheel at diametrically opposed positions, and the one-way clutches being arranged so that in one direction of angular movement of the member, one of the pinions freewheels, whilst the other is locked to the shaft to rotate with it, and vice versa in the other direction of angular movement.

A particular application of the drive unit of the invention is in a spraying machine, in which the rotation of the shaft is used to drive a rotatable fan, which, in use, provides an air blast to propel spray droplets from a spinning disc atomiser, rotation of the atomiser drive shaft being produced from the rotatable shaft by means of a flexible drive on the end thereof.

The angular movement of the member is produced by the machine operator reciprocally moving an operating handle, this movement thus also causing the fan and atomiser to oscillate whilst rotating. The machine is intended to be carried on the operator's back and thus the manual up and down operation of the handle by the operator is the sole motive force required to provide the oscillation of the air blast, as well as the spinning of the atomiser.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic, cut-away, part-sectional side view of a spraying machine incorporating a drive unit of the invention, Figure 2 is a part-sectional plan view of the machine of Figure 1, and Figure 3 shows the method of operation of the machine, in use.

The spraying machine shown in the drawings includes a tubular carrying frame 10 intended to be secured onto the back of an operator 11, as shown in Figure 3. The frame 10 is generally L-shaped in side view, as shown in Figure 1, and, in plan view, has a trapezoidal base part, as can be seen from Figure 2.

Fixed on the frame base part at the rear thereof, is a generally U-shaped support member 12, parallel sides 13, 14 of which are normal to the plane of the longer limb of the L-shaped frame. Secured by screws to the inner surface of the side 13 is a crown wheel 15 with gear teeth 16 therearound.

Near its upper, free end, the side 13 has a circular section aperture 17 containing a bearing 18 rotatably to mount a shaft 19 of an angularly movable member 20.

The shaft 19 also passes, with clearance, through a co-axial circular section aperture 21 in the centre of the crown wheel 15. Integrally formed at the end of the shaft 19, and normal to the axis thereof, is a rectangular plate part 22 of the member 20, the part 22 being disposed within the circular area of the crown wheel inside the annulus of gear teeth 16. At its opposite ends, the part 22 has respective straight arms 23, 24, respectively, extending normally from the part 22, so that the member 20 is effectively bifurcated.

In the same way as for the side 13, the side 14 also has a circular section aperture, denoted by numeral 25, the aperture containing a bearing 26, the apertures 17, 21 and 25 being on a common axis A. A rotatably mounted stub shaft 27 is received in the bearing 26, the shaft 27 being integrally formed on a rectangular base 28 of a generally U-shaped support member 29, having parallel sides 30, 31 respectively, the base lying against the inner surface of side 14 of member 12 and the sides 30, 31 extending normally from the base 28. The respective free ends of the arms 23, 24 extend to contact the inner surface of the base 28, and are secured thereto by screws.

The sides 30, 31 extend parallel to, and outside the arms 23, 24 and crown wheel gear teeth 16. Rotatably carried by the arms 23, 24 and sides 30, 31 is a cylindrical shaft 32. An end of the shaft 32 extends beyond the side 30 and has a stop 33 fixed thereon.

The shaft passes through apertures in the sides 30, 31 and is carried by respective bearings 34, 35 in apertures in the arms 23, 24.

The shaft 32 carries pinions 36, 37 which are spaced along its axis and which mesh with the gear teeth 16 of the crown wheel 15, the pinion 36 thus being disposed between arm 23 and side 30, with pinion 37 being disposed between arm 24 and side 31. The pinions are mounted on respective needle roller bearing clutches 38, 39 of the type which act as bearings, but only permit rotation about the shaft in one direction, with any attempt to reverse the rotation direction resulting in a locking of the clutch device to the shaft. These clutches 38, 39 are fitted into the pinions in a 'back-to-back' fashion.

Bolted to the outer surface of the side 31 is a gearbox 40 into which an end of the shaft 32 extends. The gearbox 40 has an output shaft 41 having a fan 42 thereon, a fan guard 43 being fixed to the outside of the gearbox. At its free end, the output shaft 41 from the gearbox carries a flexible disc 44, and at its edge this disc bears against a drive shaft 45 of a rotary atomiser 46, of the spinning disc type, the atomiser being firmly mounted on the fan guard and arranged through an opening at the front thereof aligned with the disc 44. Liquid to be sprayed is fed conventionally from a suitable container, via a tube, to an inside surface of the rotary atomiser 46.

Conveniently the container is mounted on the frame 10, and in such a manner that the liquid is fed by gravity.

The shaft 19 extends to the outside of the side 13 of the member 20, where a cranked operating handle 47 is secured to said shaft 19 at a right-angle, the handle extending around one side of the upright part of the frame 10 to a position where it can be manually grasped by the operator 11 carrying the machine, as shown in Figure 3.

Accordingly, as will now be explained, the use of the drive means of the invention in this spraying machine allows the utilisation of the power of the operator who carries the machine to provide the motive force for the fan and atomiser, thereby obviating the need for batteries, petrol engines etc.

In use, the machine frame 10 is fixed on the operator's back as shown in Figure 3. In this position the handle 47 extends forwardly for the operator to grasp, and with the member 20 horizontal, as shown in Figure 1, the outlet of the rotary atomiser 46 is approximately 1.25m from the ground. Bush crops often extend from ground level to a height of 2m and it is thus necessary for the direction of spraying to be movable up and down.

In use, the operator moves the handle 47 up and down, this angular movement taking place, for example, at 450 each side of a central, generally horizontal position, with stop means being provided to limit the handle movement.

In operation, upward movement for example, of the handle causes the member 20, attached to the handle, to move angularly about the axis A in a clockwise direction as viewed in Figure 1. Accordingly the member 29, secured to member 20, also moves angularly in a clockwise direction about axis A, and the shaft 32 carried by members 20 and 29 likewise moves clockwise.

This movement of the shaft causes its pinions 36, 37 to rotate as they move around the crown wheel with which they engage, as the member 20 and the crown wheel have the same centre on the axis A.

However, as mentioned, the clutches 38, 39 are arranged 'back-to-back' so that although there is rotation of both of the pinions, only one pinion is locked onto the shaft via its clutch, the other pinion freewheeling.

Thus the shaft 32 is rotated by said one pinion in one direction, this rotation being converted by the gear box 40 into rotation of the output shaft 41 and thus rotation of the fan 42 and disc 44. Typically the gear box converts a handle operation of 30 operations per minute into a fan speed of approximately 1,500rpm.

The ratio of the disc diameter to the atomiser drive shaft is, for example, 10 to 1, giving a theoretical atomiser speed of 15,OOOrpm. The atomiser is of the general type described as a spinning disc sprayer.

Different types of atomiser could however be used.

Although convenient, it is not essential that the drive to the fan is also used to drive a shaft of the atomiser,* and instead the air blast could merely be used to rotate a propeller on the atomiser to produce the necessary atomiser rotation. In the described embodiment, however, the atomiser drive shaft can be serrated to increase the engagement with the shaft 41 when being driven thereby. In practice, when spinning with the fan, the flexible disc, which is of rubber approximately 1.5mm thick, becomes, under centrifugal forces, a rigid, powerful, low energy consuming means of driving the atomiser.

Accordingly the described upwards movement of the handle 47 will cause rotation of the fan in one direction to provide an air blast to propel discharged droplets away from the spinning rotary atomiser. At the same time the fan guard, fan and atomiser will be angularly moved downwardly as the handle is moved upwardly, until the handle reaches its upper stop. The fan guard will then be in the lowermost position, with the atomiser directing the droplets downwardly as shown by the downwardly extending line in Figure 3.

If the handle is now moved downwardly through its permitted 900 to its lower stop, the members 20 and 29 now rotate anti-clockwise, as viewed in Figure 1, and the previously freewheeling pinion now locks onto the shaft 32 and rotates it in the same direction as it is already rotating, so that the rotary motion of the shaft is continuous. The other pinion now freewheels.

As the handle is moved downwardly, the fan guard is moved angularly upwardly to reach its upper position, with the droplets from the atomiser being directed upwardly as shown by the upwardly directed line in Figure 3. Accordingly the fan and atomiser oscillate through 900 so that liquid is sprayed over the whole height of bushes 48 even if they are relatively high.

Thus as the handle is moved up and down, the atomiser disc is rotated to discharge liquid, which is provided with an air blast from the rotating fan, so that the liquid is discharged over an angular range by virtue of said oscillation. The whole spraying machine is thus powered by the manual operation of a single handle, as a result of the use of an efficient, yet simple drive unit.

As well as providing an air blast to the discharged droplets, it is also sometimes desirable to charge them electrostatically. Various high voltage solid state generators have previously been used, but have required the use of batteries to supply the input D.C. low voltage. With the machine described it is envisaged that such a high voltage generator could be easily and inexpensively powered by, for example, a dynamo, driven directly or indirectly from the shaft 32, for example indirectly by the fan shaft. Alternatively the high voltage could be generated from the oscillating movement acting on a piezo electric crystal device.

In an alternative embodiment, the shaft 32 could be arranged to be rotatable about its longitudinal axis, but fixed against angular movement. The crown wheel 15 would be angularly movable about its central axis by up and down movement of the handle 47. Accordingly the movement of the handle would cause rotation of the pinions and rotation of the shaft 32 in the manner already described, but because the crown wheel and not the shaft 32 now moves angularly, there would be no oscillation of the fan. The fan would merely be rotatably driven by the shaft 32 through gearbox 40, upon oscillation of the handle.

Claims

1. A drive unit comprising a member arranged to be angularly movable about an axis, a rotatable shaft, gear means on the shaft, further gear means engaged with the gear means on the shaft, angular movement of said member, in use, producing relative movement between the shaft and said further gear means resulting in rotation of the shaft.

2. A drive unit as claimed in claim 1, wherein said gear means is at least one pinion and said further gear means is a crown wheel.

3. A drive unit as claimed in claim 2, wherein the crown wheel is fixed and the shaft is carried by said member for angular movement therewith, so that when the member is angularly moved, in use, corresponding angular movement of the shaft causes said at least one pinion to be rotated by its or their engagement with the crown wheel during at least one direction of angular movement of the member.

4. A drive unit as claimed in claim 3, wherein the shaft has two pinions mounted thereon via respective one-way clutches, the pinions being engaged with the crown wheel at diametrically opposed positions thereof, and the one-way clutches being arranged so that in one direction of angular movement of the member, one of the pinions freewheels, whilst the other is locked to the shaft to rotate it, and vice versa in the other direction of angular movement.

5. A drive unit as claimed in claim 4, wherein said shaft is mounted in respective bearings in spaced arms of said member and passes through respective apertures in opposed sides of a support member secured to said member, each of the pinions being disposed between one of the spaced arms at its axially inner side and one of the opposed sides at its axially outer side.

6. A drive unit as claimed in claim 5, wherein a stop is secured on an end of the shaft which extends beyond one of said opposed sides.

7. A drive unit as claimed in claim 5 or claim 6, wherein a gearbox is secured onto an end of the shaft which extends beyond the other of said opposed sides of the support member.

8. A drive unit as claimed in any one of claims 1 to 7, wherein angular movement of said member can be effected by up or down movement of an operating handle attached to said member and extending in a direction normal to said axis, such movement causing both rotation and oscillation of said shaft.

9. A drive unit as claimed in claim 1, wherein said gear means is at least one pinion and said member is a crown wheel defining said further gear means.

10. A drive unit as claimed in claim 9, wherein said crown wheel is angularly movable and said rotatable shaft is fixed against angular movement relative thereto, so that when the crown wheel is angularly moved, in use, at least one pinion is rotated by its or their engagement with the crown wheel during at least one duration of angular movement of the crown wheel.

11. A drive unit as claimed in claim 10, wherein the shaft has two pinions mounted thereon via respective one-way clutches, the pinions being engaged with the crown wheel at diametrically opposed positions thereof, and the one-way clutches being arranged so that in one direction of angular movement of the crown wheel, one of the pinions freewheels, whilst the other is locked to the shaft to rotate it, and vice versa in the other direction of angular movement.

12. A drive unit as claimed in claim 11, wherein one end of the rotatable shaft is connected to a gearbox.

13. A drive unit as claimed in any one of claims 9 to 12, wherein angular movement of the crown wheel can be effected by up or down movement of an operating handle attached to the crown wheel and extending in a direction normal to said axis, such movement causing rotation only of the rotatable shaft.

14. A spraying machine comprising a drive unit as claimed in claim 1.

15. A machine as claimed in claim 14, wherein said gear means is at least one pinion and said further gear means is a crown wheel.

16. A machine as claimed in claim 15, wherein the crown wheel is fixed and the shaft is carried by said member for angular movement therewith, so that when the member is angularly moved, in use, corresponding angular movement of the shaft causes said at least one pinion to be rotated by its or their engagement with the crown wheel during at least one direction of angular movement of the member.

17. A machine as claimed in claim 16, wherein the shaft has two pinions mounted thereon via respective one-way clutches, the pinions being engaged with the crown wheel at diametrically opposed positions thereof, and the one-way clutches being arranged so that in one direction of angular movement of the member, one of the pinions freewheels, whilst the other is locked to the shaft to rotate it, and vice versa in the other direction of angular movement.

18. A machine as claimed in claim 17, wherein said shaft is mounted in respective bearings in spaced arms of said member and passes through respective apertures in opposed sides of a support member secured to said member, each of the pinions being disposed between one of the spaced arms at its axially inner side and one of the opposed sides at its axially outer side.

19. A machine as claimed in claim 18, wherein rotation of said shaft, in use, is arranged to drive a fan.

20. A machine as claimed in claim 19, wherein a gearbox is secured to an outer surface of one of said sides of the support member, and an end of the shaft is received in the gearbox so that, in use, rotation of the shaft is converted into rotation of an output shaft of the gearbox which carries said fan.

21. A machine as claimed in claim 20, wherein the fan is disposed in a guard on which a rotary atomiser is mounted and arranged through a front opening therein.

22. A machine as claimed in claim 21, wherein angular movement of said member can be effected by up or down movement of an operating handle attached to said member and extending in a direction normal to said axis, such movement causing, in use, both rotation and oscillation of said shaft, and thus oscillation of said fan guard and said rotary atomiser mounted thereon.

23. A machine as claimed in claim 14, wherein said gear means is at least one pinion and said member is a crown wheel defining said further gear means.

24. A machine as claimed in claim 23, wherein said crown wheel is angularly movable and said rotatable shaft is fixed against angular movement relative thereto, so that when the crown wheel is angularly moved, in use, at least one pinion is rotated by its or their engagement with the crown wheel during at least one duration of angular movement of the crown wheel.

25. A machine as claimed in claim 24, wherein the shaft has two pinions mounted thereon via respective one-way clutches, the pinions being engaged with the crown wheel at diametrically opposed positions thereof, and the one-way clutches being arranged so that in one direction of angular movement of the crown wheel, one of the pinions freewheels, whilst the other is locked to the shaft to rotate it, and vice versa in the other direction of angular movement.

26. A machine as claimed in claim 25, wherein rotation of said rotatable shaft, in use, is arranged to drive a fan.

27. A machine as claimed in claim 26, wherein one end of said rotatable shaft is connected to a gearbox so that, in use, rotation of the rotatable shaft is converted into rotation of an output shaft of the gearbox which carries said fan.

28. A machine as claimed in claim 27, wherein the fan is disposed in a guard on which a rotary atomiser is mounted and arranged through a front opening therein.

29. A machine as claimed in claim 28, wherein angular movement of the crown wheel can be effected by up or down movement of an operating handle attached to the crown wheel and extending in a direction normal to said axis, such movement causing rotation only of the rotatable shaft and thus rotation of said fan.

30. A machine as claimed in any one of claims 21, 22, 28 and 29, wherein the output shaft carries a flexible drive arranged to rotate a drive shaft of the rotary atomiser.

31. A machine as claimed in claim 30, wherein the flexible drive is a flexible disc which at its edge bears against the drive shaft of the rotary atomiser.

32. A machine as claimed in either claim 21 or claim 28, wherein the rotary atomiser has a propeller which is arranged to be rotated by an air blast from said fan, in use, to produce rotation of the atomiser.

33. A machine as claimed in any one of claims 21, 22, and 28 to 32, including means for electrostatically charging droplets discharged from said rotary atomiser.

34. A machine as claimed in claim 33, wherein said charging means is a high voltage generator powered by a dynamo driven directly or indirectly from said rotatable shaft.

35. A machine as claimed in claim 33, wherein said charging means is a piezo electric crystal device.

36. A machine as claimed in claim 22 or claim 29, wherein respective stop means are provided to limit both the upwards and the downwards movement of the operating handle.

37. A machine as claimed in any one of claims 14 to 36, wherein the drive unit includes a support member fixed to a carrying frame intended to be secured onto the back of an operator, in use.

38. A drive unit substantially as hereinbefore described with reference to and as shown in Figures 1 and 2 of the accompanying drawings.

39. A spraying machine substantially as hereinbefore described with reference to and as shown in the accompanying drawings.