Soil cultivating implements

#For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:

#FIG. 1 is a schematic plan view of an implement comprising a construction in accordance with the invention,

#FIG. 2 is an enlarged sectional elevation taken on the line II--II in FIG. 1,

#Referring to FIGS. 1 to 3 of the accompanying drawings, the soil cultivating implement or rotary harrow that is shown in FIG. 1 comprises a hollow box-shaped frame portion 1 extending perpendicularly transverse to the intended direction of operative travel A. Beneath the horizontally disposed frame portion 1, a plurality of soil working members are arranged at equal intervals by means of corresponding upright shafts 2 whose longitudinal axes are normally vertical or substantially vertical. The distance between the axes of the shafts 2 of immediately neighbouring soil working members 3 is not greater than 30 cms. and preferably amounts to substantially 25 cms. Each of the shafts 2 is provided, inside the hollow frame portion 1, with a corresponding straight- or spur-toothed gear wheel 4 so that two gear wheels 4 on the shafts 2 of adjacent soil working members are drivably interconnected. Near the center of the hollow frame portion 1, a shaft 2 of one of the soil working members 3 is extended upwardly into a gear box 5. Inside the gear box 5 the shaft extension is connected through a horizontal shaft extending in the direction A and a change-speed gear 6 with a further shaft that also extends in the direction A and that is located above the former horizontal shaft, which upper shaft can have its leading splined end coupled through a known auxiliary shaft 7 with the power take-off shaft of a tractor or other operating vehicle (FIG. 1). The hollow frame portion 1 is provided at its ends with screens 8 which are movable upwardly and downwardly during operation and which are connected by arms 9 with the top of the hollow frame portion 1 so as to be pivotable about axes extending parallel to the direction A. The hollow frame portion 1 is furthermore provided at its ends with rearwardly extending arms 10 which are pivotable upwardly and downwardly and fixable in a plurality of positions relative to the frame portion 1. Between their rearmost ends, the arms 10 hold a rotatable supporting member 11, in the form of an open ground roller, with the aid of which roller the working depth of tines of the soil working members 3 can be controlled. The front of the hollow frame portion 1 is provided with a coupling member or trestle 12 by which the implement can be attached to the three-point lifting device or hitch of the tractor or other vehicle.

#As stated above, each soil working member 3 is rotatable with a corresponding upright shaft 2 relative to the hollow frame portion 1. Each shaft 2 has, near its center, a smooth or plain portion 13 which is flanked above and beneath by splined portions 14 and 15, each of which portions 14 and 15 terminates in a plain stub shaft 16 and a screw-threaded stub shaft 17, respectively (FIG. 2). The splined portion 15 is interrupted centrally by a narrowed plain part 18 which facilitates manufacture. Near the junction of the portion 14 with the stub shaft 16, a groove holds a ring 19 consisting of two identical parts. The ring 19 serves as a locking ring for the gear wheel 4, the bottom of whose hub abuts against a ball bearing 20 arranged around the smooth or plain portion 13 of the shaft 2. The hub of the gear wheel 4 supports, at its top, a sleeve-like ring 21 provided at its upper end with a rim or flange that is directed both inwardly and outwardly, the lower end of said ring 21 retainingly enclosing the two parts of the ring 19. The rim or flange at the top of the sleeve-like ring 21 holds a ball bearing 22 which is arranged around the plain stub shaft 16 and is accommodated in a housing 23 that is supported in a hole in the top of the hollow frame portion and which is fixed in place by bolts 24. The ball bearing 20 is enclosed in a housing 25 which is held in a hole in the bottom of the hollow frame portion 1 and which is fastened in place by bolts that co-operate with a fastening ring 26. Beneath the bearing 20, which is supported by a circlip 27 with respect to the housing 25, a spacing sleeve 28 is arranged inside the housing 25. The spacing sleeve 28 is surrounded by an oil seal 29, which is enclosed between the circlip 27 and a locking ring 30 located just inside the lower rim of the housing 25. Against the locking ring 30 bears the top of a support 31 that is preferably formed from a cast metallic material, such as steel, said support 31 being slipped onto the splined portion 15. The bottom of the support 31 is engaged by a locking washer 32 which is urged against the bottom of the support by a nut 33 screwed onto the screwthreaded stub shaft 17. The support 31 has recesses 34 located diametrically opposite one another on either side of the axis of rotation of the corresponding soil working member 3, said axis being afforded by the longitudinal center line a of the shaft 2 concerned. The recesses 34 are open on the bottom. Each of the recesses 34 holds a loop-like fastening portion 35 of a corresponding tine 36 which is fixed by a pin 37 passed through the loop in the recess 34 and located between the ends of the tine. The pin 37 is passed through two registering bores in the support 31 and is held in place at one end by a ring 38 and a spring pin 39 (FIG. 3). The pin 37 with the ring 38 and the spring pin 39 together constitute a quick-release for fastening the tine 36. The loop-like fastening portion 35 is freely pivotable to a limited extent about the pin 37. The walls of the recesses 34 serve as stops and the longitudinal axis b of the pin 37 constitutes a pivotal axis which is inclined to the axis of rotation a of the soil working member 3 at least substantially at right angles and extends tangentially to that axis.

#Each tine 36 of each soil working member 3 is made from leaf spring steel of a thickness of at least 5 mms. and a width of at least 50 mms.; it is secured so that its broader surfaces extend at least substantially tangentially to the axis of rotation a of the corresponding soil working member 3. The tine 36 comprises two operative portions 40 and 41 which are located one above the other and which extend, at least by a predetermined part, in the same direction. Away from the point where the ends of the loop-like fastening portion 35 are clamped together by a rivet 42, the upper operative portion 40 initially extends by a straight portion in an upward direction and slightly towards the axis of rotation a and then, after a curve of about 180.degree., it terminates in a straight portion extending downwards and outwards. The portion 40 is slightly torsioned twisted about its longitudinal axis throughout its length so that, with respect to the intended direction of operative rotation, its front edge is at a larger distance from the axis a than is its rear edge. Considered in the same direction, each portion 40 occupies a trailing disposition. The free end of the upper operative portion 40 is bent over at right angles (see FIG. 2). The lower operative portion 41 of the tine 36 extends away from the fastening portion 35 through a slide outwardly directed curve and then at least substantially parallel to the axis a. The free end of the lower operative portion 41 is nearer to the axis a than is the free end of the upper operative portion 40. Away from the curved, the downwardly extending portion of the operative portion 41 is torsioned about its longitudinal axis so that, considered in the intended direction of operative rotation of the soil working member 3, the front edge is further spaced from the axis a than is the rear edge. Moreover, considered in the intended direction of operative rotation of the soil working member 3, the operative portion 41 is also in a trailing disposition. Each pair of tines 36 is capable of turning so that the free ends of the lower operative portions 41 thereof can come into contact with one another in the neighbourhood of an imaginary extension of the axis a (FIG. 3). As is shown in FIG. 2, each rivet 42 is located wholly or principally inside the corresponding recess 34, viewed in the direction of the axis a.