GB2177885A

GB2177885A - Agricultural drills

Info

Publication number: GB2177885A
Application number: GB08518863A
Authority: GB
Inventors: Kenneth Ian Withers
Original assignee: AGCO Manufacturing Ltd
Current assignee: AGCO Manufacturing Ltd
Priority date: 1985-07-25
Filing date: 1985-07-25
Publication date: 1987-02-04
Also published as: WO1987000392A1; AU6137586A; ZA865529B; GB8518863D0

Abstract

An agricultural drill comprising a frame (1) carrying a hopper (2), a plurality of coulters (5) pivotally mounted on the frame (1) and spaced laterally across the width of the drill, and an actuating mechanism comprising a rotatable control member (14) and force transmitting springs (24) connected between the control member (14) and the coulters (5) so that rotation of the control member (14) loads the coulters (5) towards working engagement with the ground, characterized in that the coulters (5) are pivotally connected (22) to the rotatable control member (14) so that rotation of the control member (14) loads the force transmitting springs (24) while the coulters (5) are held against rotation by contact with the ground.

Description

SPECIFICATION Agricultural drills This invention relates to agricultural drills, especially the coulter mounting and actuating mechanism of agricultural drills.

Pneumatic drills comprise a frame carrying a central seed hopper, metering means to dispense seed from the hopper, and distribution means to convey the seed in a fiow of air to coulters spaced laterally across the width of the drill. The coulters are pivotally mounted on the frame and are forced into work under control of an actuating mechanism comprising a rotatable control member connected to each coulter via an associated force transmitting spring. Generally, the construction is lightweight and the drill is designed to be semi-mounted so as to reduce cost and increase work rate.

In known pneumatic drills, the coulters are pivotally mounted on a transverse beam so as to trail behind the beam, and the rotatable control member extends generally parallel to the beam and carries a plurality of levers each associated with a coulter and being connected thereto by a respective force transmitting tension spring. The loading of the springs, and thus the depth of penetration of the coulters, is determined by the angular setting of the rotatable control member, which in turn is controlled by manual adjustment means. A characteristic of this arrangement is that the tension in the force transmitting springs produces a reaction that increases the force needed to operate the manual adjustment means.

An object of the present invention is to simplify the known coulter mounting and actuating mechanism and to make it easier to adjust for depth control.

According to the present invention, an agricultural drill comprises a frame carrying a hopper, a plurality of coulters pivotally mounted on the frame and spaced laterally across the width of the drill, and an actuating mechanism comprising a rotatable control member and force transmitting springs connected between the control member and the coulters so that rotation of the control member loads the coulters towards working engagement with the ground, characterised in that the coulters are pivotally connected to the rotatable control member so that rotation of the control member loads the force transmitting springs while the coulters are held against rotation by contact with the ground.

By mounting the coulters directly on the rotatable control member, the need for a separate coulter mounting beam and control member is avoided, and a simpler, lighter and less costly assembly is produced.

Also, because the coulter and force transmitting springs move together as an assembly with rotation of the control member, the springs are not loaded until the coulters engage the ground and move relative to the control member. Thus, adjustment of the angular setting of the control member by a suitable manual adjustment means is easily accommodated before the coulters are put into work. It is only when in work that the coulters are loaded by the springs and a reaction is exerted on the control member and its adjustment means.

The invention will now be described by way of exampie with reference to the accompanying drawings in which: Figure lisa side elevation of a pneumatic drill according to the invention, Figure 2 is a side elevation of a bearing and the adjustment means for the control member in Figure 1,and Figure 3 is a rear elevation of the bearing and adjustment means of Figure 2.

The illustrated drill comprises a frame 1 carrying a seed hopper 2. A plurality of seed metering mechanisms 3 dispose seed from the hopper into pneumatic distribution means 4 that conveys the seed in a flow of air to each of a plurality of coulters 5 pivotally mounted on the frame. The seed metering mechanisms 3 are mounted in two rows across the width of the hopper, one beneath each inclined bottom walls 6 of the hopper, and each delivers seed into pneumatic distribution means comprising a venturi unit 7 and a length of tube 8 connecting the unit 7 to an associated coulter 5. The venturi units 7 are connected to a common air manifold 9 that is pressurised by an air pump 10.

Tractor mounting points 11 are provided on the front of the frame 1 for connection of the drill to the rear lifting links of a tractor.

A pair of landwheels 12 are mounted on the frame so as to support the drill when it is lowered onto the ground for work, and a transmission system 13 between the landwheels and the metering mechanisms serves to drive the latter and dispense seed.

A rotatable control beam 14 is mounted in a pair of bearings 15 (Figures 2 and 3) so that it extends laterally across the width of the drill. Each bearing 15 is a plane bearing comprising a two-part outer support 16 connected to the frame 1 and an inner ring 17 that is connected coaxially to the control beam 14 and is rotatably received in a circular cutout 18 in the outer support 16. A pair of bolted flanges 19 hold the two parts of the outer support 16 together and overlap the edges of the inner ring 17 to hold it captive.

Each coulter comprises an arm 20 that carries a furrow opening tool 21 at its rear end and which is pivotally connected to the control beam 14 at its leading end via a pivot pin 22 engaging a bracket 23 projecting upwards from the top of the control beam. A pair of tension springs 24 are connected between the arm 20 of each couiter and a bracket 25 that projects downwards from the underside of the control beam, thereby to act in pulling the coulter downwards.

When the drill is lifted off the ground to take the coulters out of work, the weight of the coulters and the tension springs 24 swing the coulters arms downwards to a lowermost position in which the coulters engage the control beam. When the drill is lowered onto the landwheels to bring the coulters into work, the coulters swing upwards by contact with the ground and extend the springs 24to increase the tension therein.

The weight of the coulters and the loading of the springs 24 therefore urge the tools 21 into work and determine the sowing depth of the coulters. In order to vary this depth, the angular setting of the control beam within the bearings 15 can be adjusted by a manual adjustment means 25 (figures 2 and 3). It will be clear from Figure 1, that anti-clockwise rotatidn of the control beam by the adjustment means 25 will further extend the springs 24 and therefore increase the tension therein.

The adjustment means 25 comprises a lever arm 26 connected to the control beam 14 and a vertical shaft 27 rotatably supported in a bearing 28 and having a lower portion 29 on which is threaded a sleeve 30 that cooperates with the end of lever arm 26 so that rotation of the shaft 27 moves the sleeve axially on the shaft and therefore pivots the lever arm 26. A bevel gearwheel 31 at the upper end of the shaft 27 engages a bevel gearwheel 32 on a crossshaft 33, and the outer free end 34 of the cross-shaft 33 is adapted for engagement by a winding handle, whereby shafts 33 and 27 can be rotated to move the lever arm 26 and adjust the angular setting of the control beam 14.

It will be appreciated that when the drill is lifted out of work, the coulters assume their lowermost position and the tension in the springs 24 is reduced. The turning movement exerted on the control beam 14 is therefore at its minimum and minimum loads are exerted on the adjustment means 25 to produce operating resistance. The angular setting of the control beam can therefore be adjusted easily.

As will be seen in Figure 1, the coulters 5 are of two lengths one set having long arms 20 and the other set having short arms 20 so that the tools 21 of each set are spaced apart in the direction of travel.

Accordingly, the geometry of the tension springs 24 for the long and short coulters is also made different for each so as to ensure that the loading characteristics of both are the same. Adjustment of the control beam 14 then produces the same effect on sowing depth for both the long and short coulters.

Claims

1. An agricultural drill comprising a frame carrying a hopper, a plurality of coulters pivotally mounted on the frame and spaced laterally across the width of the drill, and an actuating mechanism comprising a rotatable control member and force transmitting springs connected between the control member and the coulters so that rotation of the control member loads the coulters towards working engagement with the ground, characterised in that the coulters are pivotally connected to the rotatable control member so that rotation of the control member loads the force transmitting springs while the coulters are held against rotation by contact with the ground.

2. A drill as claimed in claim 1 in which the coulters comprise arms that are pivotally connected to the control member at their leading ends, and the force transmitting springs comprise tension springs that are connected at one end to the arm of a respective coulter and at the other end to the control member at a point below the pivot connection of the coulters so as to load the arm downwards into working engagement with the ground.

3. A drill as claimed in claim 1 or 2 including adjustment means that serves to control the angular setting of the control member about its own longitudinal axis.

4. A drill as claimed in any one of the preceding claims which is provided with mounting means for connection to the lifting links at the rear of a tractor.

5. A drill as claimed in any one of the preceding claims which is provided with metering means to meter material from the hopper and pneumatic distribution means to convey metered material from the metering means to the coulters.

6. An agricultural drill provided with coulter mounting and actuating means substantially as herein described with reference to the accompanying drawings.