GB2030036A - Direct drill - Google Patents

Abstract

A direct drill having a main frame 14 is towed in use by a tractor by means of a tow-bar 16 which is adjustably connected to the frame such that the operative attitude of the frame relative to the ground, and thus the depth of penetration of slit-opening disc-coulters 20, can be varied to suit different ground conditions. To accommodate unequal wear of individual coulters 20, they are adjustably mounted on support beams 124 by means of slots 134, 136 and bolts 138. <IMAGE>

Description

SPECIFICATION Drill for sowing seed or seed and fertilizer This invention relates to drills for sowing seed or seed and fertilizer and in particular, though not exclusively, to such drills which are intended for, or whose primary function is, direct drilling i.e. sowing seeds without first carrying out the traditional tillage operations.

Although direct drilling is now a well-known and widely accepted technique, there are still areas of design in drills for this technique which have not yet been satisfactorily dealt with, at least so far as concerns published and used drill designs. One such area relates to the provision of means to accommodate both variations from place to place in the resistance of the untilled ground to penetration by the coulters of the drill, and variations in the degree of wear of the coulters of the drill.

As far as variation in penetration resistance is concerned, accommodation of such variations is not just a matter of varying the downthrust on the coulters appropriately.

For example, if a drill incorporates triple disc coulters or some other coulter incorporating a leading single disc, then, to effect efficient penetration of particularly hard ground it is desirable to increase the proportion of down-thrust exerted on the leading disc which effects initial penetration of the ground for each coulter.

With regard to variations from one coulter to the next in the degree of wear of the coulters of the drill, such variations can arise, for example, from use of the drill first for a crop having wide row spacings necessitating the removal of alternate coulters, and then for a crop having standard row spacings necessitating the replacement of these coulters.

An object of the invention is the provision of a drill having improved means for accommodating the variations discussed above.

According to the invention there is provided a drill for sowing seed or seed and fertilizer comprising: ground wheels; a frame mounted on the ground wheels; a drawbar mounted on the frame whereby the drill can be towed by a tractor; a hopper for seed or seed and fertilizer, the hopper being mounted on the frame and extending transverse to the direction of operative forward motion of the drill across substantially the full sowing width of the drill; a series of coulters to open furrows in the ground;; a mounting for each coulter whereby the coulter is mounted on the frame so that the coulter can be raised and lowered relative to the frame and so that the coulter is held at a defined attitude with respect to the frame at any given coulter working depth, the coulters being located under the hopper at positions spaced apart in a direction transverse to the direction of operative forward motion of the drill; each coulter mounting comprising attitude adjustment means whereby the attitude of the coulters relative to the frame for a given coulter working depth can be adjusted; actuating means for the coulters whereby the coulters can be lowered relative to the frame and caused to open furrows in the ground; delivery means operable in use to deliver seed or seed and fertilizer from the hopper to said furrows in the ground; and height adjustment means for said drawbar whereby the height of the forward end, with respect to the direction of operative forward motion of the drill, of the drawbar is adjustable relative to the frame so that the attitude of the frame relative to the ground for a given towing height of the forward end of the drawbar during use, can be adjusted.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 shows a section through a combined seed and fertilizer drill, including a drawbar and coulter assemblies, the section being taken in the direction F of operative forward motion of the drill; Figures 2 and 3 show exploded perspective views of a frame and of a drawbar respectively, which form part of the drill of Fig. 1; and Figure 4 shows a side elevation view of a coulter assembly which can be used in place of the coulter assemblies shown in Fig. 1.

Drill 10 shown in Fig. lisa "direct drill" intende principally for use in sowing seed into land which has not been subjected to the usual tillage operations such as ploughing and harrowing after harvesting the previous crop, or which has only undergone minimum tillage. The land is usually sprayed with a weed killer such as "Gramoxone" (Trade Mark) before sowing. Such a drill is also known as a "no-till" drill.

As shown in the drawings, drill 10 comprises ground wheels 12, a frame 1 4 mounted on the ground wheels, a drawbar 1 6 mounted on the frame whereby the drill can be towed by a tractor, a hopper 1 8 for seed and fertilizer mounted on the frame, a series of coulters 20 to open furrows in the ground, actuating means 22 whereby the coulters can be raised and lowered relative to the frame, and delivery means 24 operable in use to deliver seed and fertilizer from hopper 1 8 to the furrows opened by coulters 20. These principal parts of the drill will now be described in more detail.

Ground wheels 1 2 comprise 1 2.4 inch (width) by 24 inch (internal diameter) inflatable tyres mounted on pressed steel wheel discs having 11 inch (width) rims and jour nalled on stub shafts (not shown) carried by support sleeves 25 on frame 14 for rotation about a common axis 26.

As shown in Fig. 2, frame 14 comprises a rigid rectangular assembly of transverse front and rear beams 28 and 30 respectively, and fore/aft extending end beams 32, 34.

Drawbar 16 is shown in detail in Fig. 3 and comprised rectangular section forwardly-tapering beam 36 which fits at its rear end between a pair of apertured flanges, 38,40 welded to front beam 28 of frame 14. The drawbar is pivotally connected to flanges 38, 40 by a pivot pin 42 which passes through aligned holes 44 in the flanges and through a bearing sleeve 46 mounted in the rear end of the drawbar. Pin 42 is held in position by locking means 48.

At the forward end of drawbar 1 6 there is provided attachment means in the form of a hitch member 50 having a ball joint 52 to be inserted into the clevis (not shown) of the automatic hitch of a tractor, to receive a hitch pin.

Also mounted on drawbar 1 6 is a generally Y-shaped support 54 for a pair of hydraulic hoses (not shown) connected to actuating means 22. At each side of the drawbar a hydraulic hose fitting 56 is provided to receive the ends of the hoses when the latter are not in use.

Towards the rear end of drawbar 1 6 is provided a pair of spaced upstanding ears 58 carrying respective sleeves 60 to receive a pin 62 having an associated lynch pin 64 to secure it in position.

The rear ends of flanges 38 and 40 are likewise provided with a pair of spaced upstanding ears 66 carrying respective sleeves 68 to receive a pin 70 having an associated lynch pin 72.

A length-adjustable member in the form of a turn-buckie 74 is connected between pins 62 and 70. The turnbuckle comprises a central screw-threaded sleeve 76 having handlevers 78, and T-shaped screw-threaded end members 80, 82 having respective sleeves 84, 86 received on pins 62 and 70 respectively. The turnbuckle is lengthened or shortened by turning sleeve 76 relative to end members 80, 82.

A series of holes 88 is formed in each of the flanges 38 and 40. Each hole in one flange is aligned with a hole in the other flange to receive a bolt 90 secured by an associated nut 92, the bolt forming abutment means limiting upward pivotal movement of drawbar 1 6 by engagement with the upper surface 94 of the rear end of the drawbar.

Turnbuckle 74, pin 90 and their associated parts constitute height adjustment means for drawbar 16 whereby the height H from the ground G of the forward end 50, with respect to direction F, of the drawbar is adjustable relative to frame 14, so that the attitude of the frame relative to the ground for a given towing height H during use can be adjusted.

Hopper 18 is mounted on frame 14 so as to extend lengthwise transverse to the direction F of operative forward motion of drill 10 across substantially the full sowing width W of the drill i.e. the width of the strip of ground in which seeds are sown by the drill during each pass in a field. The hopper comprises downwardly-converging front and rear walls 96 and 98 respectively, end walls 100 and a roof-shaped partition support 102 surmounted by an upright partition wall 104 dividing the hopper into a front seed compartment 106 and a rear fertilizer compartment 108. A pair of upwardly-tapering steel plates 100, 11 2 one at each end of frame 14 support the hopper on the frame. A pair of hinged lids 114, 11 6 provide access to compartments 106, 108 and are divided by a central load ingplatform 118.

Coulters 20 each comprise a single front slit-opening disc 1 20 and a pair of rear slitwidening discs, 1 22 the three discs being journalled for rotation on a drag arm 1 24 or 126. Drag arms 124 are shorter than drag arms 1 26 and arranged alternately therewith across sowing width W, and the coulters are thus arranged in two rows 128, 1 30 which are off-set in direction F.

Each slit-opening disc is journalled for rotation in a vertical plane between a pair of mounting plates 1 32 which are formed with vertical slots 134, 1 36 and clamped on opposite sides of the respective drag arm 1 24 or 1 26 by clamping bolts 1 38 passing through the slots and through apertures in drag arms, and associated nuts and washers.

The two slit-widening discs 1 22 of each coulter are journalled on respective bearing assemblies 140 secured to the respective drag arm 1 24 or 1 26 for rotation in respective downwardly converging planes so that the discs are in a V-shaped formation at the lower portion of their peripheries.

The angle between discs 1 22 is 1 2 degrees and they make contact with each other at a point P (see Fig. 1) somewhat ahead of their bottom dead centre position.

It will be understood from the foregoing that slit-widening discs 1 22 of each coulter are mounted at a fixed position with respect to their drag arm 1 24 or 1 26 and slit opening disc 1 20 of each coulter is adjustable up and down relative to the drag arm, therefore the overall attitude of the coulter relative to the drag arm (and therefore relative to frame 14 for any given coulter working depth) can be adjusted by means of the adjustable connecting means comprising slots 134, 1 36 and bolts 138, and these latter components thus constitute attitude adjustment means for the coulter.

Each coulter 20 is mounted on frame 14, so that the coulter can be raised and lowered relative to the frame so that the coulter is held at a defined attitude with respect to the frame ar any given coulter working depth, by the coulter's drag arm 1 24 or 1 26.

The drag arms are pivotally connected to the frame by means of pivot pins 142 which extend through bushes provided in the forward ends of the drag arms and through respective pairs of apertured ears 1 44 welded to the lower side of front beam 28 of frame 14. The short drag arms 1 24 are arranged alternately with the long arms 1 26 across the sowing width W of the drill. It will be noted that coulters 1 20 are located under hopper 1 8 and are spaced apart in a direction transverse to direction F.

Actuating means 22 whereby coulters 20 can be raised and lowered relative to frame 14 comprises a pair of double-acting hydraulic rams 1 46 mounted on the frame in upright attitudes and at positions which are spaced apart in a direction transverse to direction F.

The rams are each pivotally mounted (see axis 147) in a yoke formed by a pair of bridge shaped plates 148 supported between pairs of front and rear upstanding brackets 150, 1 52 respectively, welded to beams 28 and 30 of frame 14. Plates 148 are bolted to front and rear support arms 154, 1 56 respectively which are themselves pivotally connected between brackets 1 50 and 1 52 respectively.

The rams are arranged with their cylinders uppermost and the lower end of the piston of each is directly pivotally connected about an axis parallel to axis 1 47 to a transverse boxsection coulter actuating beam 1 58 so as to raise and lower the beam relative to frame 1 4 during use. Due to the upright attitude (in the working position) of rams 146, their direct connection to beam 158, and their lateral alignment with the beam (i.e. they and the beam lie in a common vertical plane extending laterally with respect to direction F), in the working (as opposed to transport) position of coulters 20, any given extension or retraction of rams 1 46 causes substantially the same given up or down movement of beam 1 58 relative to frame 14.

Coulter actuating beam 1 58 is connected to the individual coulters 20 by resilient means in the form of two series of ellipsoidal rubber springs 160, 162, the springs 1 60 of the front series being connected to the short coulter drag arms 1 24 for the transmission of down-thrust thereto, and the springs 1 62 of the rear series being likewise connected to the long coulter drag arms 126. Springs similar to springs 160, 1 62 are more fully described in patent no, 1,536,426.

The attitude of the coulter actuating beam 1 58 is maintained, to ensure that the proper distribution of down-thrust between the long and short coulter drag arms 124 and 1 26 is maintained, by means of a pair of parallelogram linkages.

Each parallelogram linkage comprises upper and lower links 1 64 and 1 66 respectively, pivotally connected between pairs of upstanding brackets 1 68 and 1 70 on front beam 28 and on coulter-actuating beam 1 58 respectively. Upper links 1 64 are in the form of turnbuckles so as to be length-adjustable whereby adjustments to the attitude of beam 1 58 can be made.

Delivery means 24 which delivers seed and fertilizer from hopper 1 8 to the furrows opened by coulters 20 is more fully described in U.K. patent No. 1,525,566. For present purposes it suffices to say that the delivery means comprises two series of resilient dispensing rollers 1 72 and 1 74 for seed and fertilizer respectively. The rollers of each series are mounted on respective common shafts and are rotated in the directions indicated.

Each roller co-operates with its own glass dispensing plate 1 76 and dispenses seed or fertilizer at a predetermined rate into its own assembly of rubber funnel 1 78 and convoluted rubber delivery tube 1 80 leading to a drop tube 1 82 between coulter discs 1 22.

In use, drill 10 is drawn by a tractor and rams 46 are pressurized by the tractor to press coulters 20 into the ground. Dispensing rollers 1 72 and 1 74 dispense seed and fertilizer into the furrows opened by the coulters.

For such use, slit opening discs 1 20 are set so as to "lead" the slit-widening discs 1 22 in the sense of being positioned, relative to discs 122, so as to penetrate the soil by an appropriate amount (known as the lead) more than discs 1 22. The lead of discs 1 20 should be about 1 8 millimetres for cereals and is reduced to about 5 millimetres for small seeds such as kale.

Discs 1 20 can be easily adjusted by means of slots 134, 1 36 and bolts 1 38 in order to produce the required "lead" for any given depth of coulter penetration and to restore the required lead after discs 1 20 have been reduced in diameter by wear more than discs 1 22 (due to the higher loading of discs 120).

When it is desired to change the lead of all the slit opening discs 1 20 for any given depth of coulter penetration, this can be achieved very quickly and simply by adjusting the attitude of drawbar 1 6 relative to frame 1 4. To increasethe lead the drawbar is adjusted upwards, and vice versa. Such adjustment is carried out quickly and simply by slackening turnbuckle 74, repositioning bolt 90 in the appropriate pair of holes 88 and then retightening the turnbuckle to lock the drawbar against the bolt for load-taking purposes.

Fig. 4 shows an alternative coulter and drag arm assembly 1 84 for use in drill 10 in place of coulters 20. Assembly 1 84 comprises a drag arm 1 86 on which a slit-opening disc 188 is mounted in the same manner as discs 120, by means of mounting plates 1 90 hav ing slots 1 92 to receive bolts 1 94 and associated washers 1 96.

At the rear end of drag arm 1 86 a hoe type coulter element 1 98 having seed and fertilizer drop tubes 200 and 202 is angularly adjustably mounted by means of bolts 204, 206 and an arc of apertures 208 formed in the drag arm.

Among modifications which could be made in the above embodiments, which nevertheless fall within the scope of the invention are the following: 1. the use of a tyne in place of hoe type coulter element 198; 2. use of drill 10 as a seed only drill with or without hopper partition 104; 3. the use, in place of single drag arms 124, 126, of pairs of upper and lower spaced links (preferably arranged as a parallelogram linkage) pivotally connected at their forward ends to frame 14 and at their rearwards ends to coulters 20 or 1 84. In such a case, the attitude adjustment means for the coulters can be as described in the above embodiments or can be means (for example a screw jack or turnbuckle ) for adjusting the length of one link of each pair;; 4. the use of an alternative height adjustment means for drawbar 1 6 whereby the height of its forward end can be adjusted with respect to frame 14. For example a linkage may be provided which pivotally interconnects the attachment means (at the forward end of the drawbar) with the remainder of the drawbar, together with a screw jack or turnbuckle or equivalent means acting between the attachment means and the remainder of the drawbar to effect adjustment of their relative positions. A suitable linkage for this purpose would be a heavy-duty parallelogram linkage.

The principal advantage of the embodiments of the invention described above lies in the wide range of facilities they provide for simple and rapid adjustment of the drill so as to accommodate different operating conditions and differing states of wear of its components - such a range of adjustments not having been previously provided on direct drills and such adjustment being a step towards the provision of a satisfactory implement to meet the exacting technical requirements of direct drilling.

Claims (11)

1. A drill for sowing seed or seed and fertilizer comprising: ground wheels; a frame mounted on the ground wheels; a drawbar mounted on the frame whereby the drill can be towed by a tractor; a hopper for seed or seed and fertilizer the hopper being mounted on the frame and extending transverse to the direction of operative forward motion of the drill across substantially the full sowing width of the drill; a series of coulters to open furrows in the ground; a mounting for each coulter whereby the coulter is mounted on the frame so that the coulter can be raised and lowered relative to the frame and so that the coulter is held at a defined attitude with respect to the frame at any given coulter working depth, the coulters being located under the hopper at positions spaced apart in a direction transverse to the direction of operative forward motion of the drill;; each coulter mounting comprising attitude adjustment means whereby the attitude of the coulter relative to the frame for a given coulter working depth can be adjusted; actuating means for the coulters whereby the coulters can be lowered relative to the frame and caused to open furrows in the ground; delivery means operable in use to deliver seed or seed and fertilizer from the hopper to said furrows in the ground; and height adjustment means for said drawbar whereby height of the forward end, with respect to the direction of operative motion of the drill, of the drawbar is adjustable relative to the frame so that the attitude of the frame relative to the ground for a given towing height of the forward end of the drawbar during use, can be adjusted.

2. A drill according to claim 1 wherein the drawbar is pivotally connected to the frame, and the height adjustment means for the drawbar comprises a length-adjustable member connectible between frame and a position between the ends of the drawbar.

3. A drill according to claim 2 wherein said length adjustable member is in the form of a turnbuckle.

4. A drill according to claim 2 or claim 3 wherein the drawbar is pivotally mounted between a pair of flanges secured to the frame, said flanges having a series of aligned holes formed in them through which a bolt or the like can be inserted so as to form abutment means limiting upward pivotal movement of the drawbar.

5. A drill according to claim 1 wherein the height adjustment means for the drawbar comprises attachment means at the forward end of the drawbar whereby the drawbar can be attached to a tractor, a linkage pivotally inter-connecting the attachment means and the remainder of the drawbar, and a screw jack acting between the attachment means and the remainder of the drawbar.

6. A drill according to any one of the preceding claims wherein each coulter mounting comprises a drag arm pivotally connected to the frame, and the attitude adjustment means for the coulter comprises adjustable connecting means connecting the coulter to the drag arm.

7. A drill according to claim 6 wherein the adjustable connecting means comprises slotted plates attached to the coulter and located on opposite sides of the drag arm and clamping bolts and associated nuts to clamp the plates to the drag arm.

8. A drill according to any of claims 1 to 5 wherein each coulter mounting comprises upper and lower spaced links, both of the links being pivotally connected at their forward ends to the frame and at their rearward ends to the coulter, and said attitude adjustment means for the coulter comprises a screw jack or turnbuckle for adjusting the length of one of the links.

9. A drill according to any one of the preceding claims wherein said actuating means for the coulters comprises two hydraulic rams mounted on the frame in an upright attitude and at positions which are spaced apart in a direction transverse to the direction of operative forward motion of the drill, the rams being laterally aligned with and directly connected to a transverse coulter-actuating beam so that given extension or retraction of the rams causes substantially the same given up and down movement of the beam relative to the frame, and the coulter-actuating beam being connected to the coulters for the transmission of down-thrust thereto by resilient means.

10. A drill according to any one of the preceding claims wherein said coulters each comprise forward slit-opening means and rearward slit-widening means.

11. A drill according to claim 10 wherein said slit-opening means comprises a rotatable disc and said slit-widening means comprises a pair of discs inclined with respect to each other so as to be in V-shaped formation at the lower portion of their peripheries.

1 2. A drill according to claim 10 wherein said slit-opening means comprises a rotatable disc and said slit-widening means comprises a tyne or a hoe.

1 3. A drill according to claim 1 wherein said height adjustment means for said drawbar is constructed substantially as described herein as shown in Fig. 3 of the accompanying drawings.