GB2050784A - Seed drill - Google Patents

Abstract

A seed drill having a fluid operated coulter actuator (18) to raise and lower the coulters, tramlining means comprising at least one seed shutter (30) operated by a fluid operated tramlining actuator (31) with a fluid connection to the coulter actuator (18) and a tramline marker (100) operated by a fluid operated marker actuator (102) with a fluid connection (105) to the tramlining actuator (31) so that it operates to make a mark during tramlining. Preferably, the marker actuator (102) has fluid connection (104, 105) to the coulter and tramlining actuators (18, 31) so as to operate in response to the pressure supplied to each, the pressure to the coulter actuator (18) controlling the marker (100) so that it can operate only when sowing, and then operating in accordance with the pressure supplied to the tramlining actuator (31) so that it marks only when tramlining. <IMAGE>

Description

SPECIFICATION Seed drill This invention relates to seed drills.

It is known to provide seed drills with tramlining means whereby the delivery of seeds from selected seed spouts can be blocked during selected bouts so as to produce crop free tracks or tramlines through the germinated crop for the passage of a vehicle that is subsequently to treat the crop, for example, by spraying or spreading fertilizer or insecticide. Further, it is known to block the delivery of seed from a seed spout using a shutter that is hydraulically operated by the pressure in a ram that raises and lowers the coulters. For example, our copending British Patent Application No. 39713/78 describes a drill having a ram that is pressurized to lower the coulters for sowing and that supplies hydraulic pressure via a control valve to hydraulic cylinder so as to open a seed shutter against spring pressure.

The control valve is controlled by a mechanical rotary counter that in indexed with raising and lowering of the coulters so as to count successive bouts, and that operates the valve periodically to block the pressure from the ram to the cylinder so that the latter remains inoperative and the delivery of seed is stopped.

An object of the present invention is to modify these known seed drills by providing them with a marker that is linked to the tramlining means so that it automatically marks the tramlines and thereby enables them to be located and used before the crop germinates.

This object is achieved according to the invention by providing a seed drill having a hydraulic ram to raise and lower the coulters, tramlining means comprising at least one seed shutter operated by a hydraulic cylinder connected hydraulically to the ram, and a marker operated by a hydraulic cylinder connected hydraulically to the cylinder of the seed shutter so that it makes a mark during tramlining.

Preferably, the marker cylinder has two hydraulic connections to the ram and shutter cylinder so as to operate in response to the pressure in each, the ram pressure controlling the marker so that it can operate only when sowing, and then operating in accordance with the pressure in the shutter cylinder so that it marks only when tramlining. Thus, in the case of a mechanical ground-engaging marker, when the ram is operated to raise the coulters at the end of each bout, the marker is also raised out of engagement with the ground if it has been operative during that bout. The drill can be turned ready for the next bout without any risk of damaging the marker.

In a preferred embodiment, the marker is hydraulically urged against spring pressure into engagement with the ground, and the pressures in the ram and shutter cylinders act against one another on opposite sides of the piston in the marker cylinder so that a fall in the pressure in the shutter cylinder during tramlining causes the ram pressure to predominate and cause marking.

The invention is now described by way of example with reference to the accompanying drawings showing a seed drill fitted with tramlining means as described in our patent application No. 39713/78 and modified so as to incorporate a marker according to the invention.

A completely description of the drill and tramlining means may be had by reference to the aforesaid patent application. However, for the purposes of explaining the present invention, only the hydraulic control systems need be described. The rams 18 control the coulter assemblies 13 and when supplied with pressure from the tractor via lines 20, 21, they act against the springs 22 to lower the coulter assemblies into sowing-engagement with the ground. The delivery of seed and fertilizer from hoppers 26, 27 to preselected coulter assemblies is controlled by shutters 30 so as to effect tramlining.

The shutters 30 are controlled by hydraulic cylinders 31 that are fed fluid from line 20 via a branch line 68, a valve 37, and lines 44,43 so that when the valve 37 is open, pressure from line 20 operates the cylinders 31 and opens the shutters 30 against springs 39. The valve 37 is controlled by a cam wheel 49 that is rotated by an index mechanism in step with the completion of each successive bout so that the valve is closed every time a predetermined number of bouts have been completed, whereupon the pressure in the cylinders 31 falls and the shutters 30 close to effecttramlining.

The tramlining marker comprises a number of tines 100 that are each mounted on the frame of the drill in longitudinal alignment with a shuttercontrolled seed spout so as to swing downwards into engagement with the ground behind the seed spout. Each tine too is pivotally mounted on the frame and is urged out of engagement with the ground by a tension spring 101.A A hydraulic piston and cylinder 102 controls raising and lowering of the tine. As shown schematically in Figure 3, the cylinder 102' is mounted on the frame and the piston rod 102" extends upwards therefrom and is connected to the lever 103 carrying the tine.

The hydraulic connections to the cylinder 102" comprise a line 104 to the upper end of the cylinder from the lines 20,21 supplying fluid to the ram, and a line 105 to the lower end of the cylinder from the line 43 or 44 supplying fluid from the valve 37 to the shutter cylinder 31.

When the drill is not in use or is being turned at the headlands between bouts, there is zero pressure in lines 20,21 and the coulter assemblies are therefore raised and the shutters 30 are closed. There is then zero pressure on both sides of the piston of the marker cylinder 102 and the marker is therefore raised by spring 101.

When the drill is sowing a bout without tramlining, the rams 18 are pressurized to lower the coulter assemblies, and, because the valve 37 is open, the shutter cylinders 31 are pressurized and the shutters 30 are held open. Thus, both sides of the piston of the marker cylinder 102 are pressurized. These pressures largely counteract one another leaving just a small net upwards force that together with spring 101 holds the marker in the raised position.

However, when the drill is sowing and tramlining, the valve 37 is closed and the pressure in the shutter cylinders falls to zero allowing the shutters to close, and causing the pressure in the lower part of the marker cylinder 102 to fall to zero. The pressure in the upper part of the cylinder 102 then acts to urge the tine 100 downwards against the action ofthe spring 101 and a mark is made in the ground along the length ofthe unsown tramline.

Claims (11)

1. A seed drill having a fluid operated coulter actuator to raise and lower the coulters, tramlining means comprising at least one seed shutter operated by a fluid operated tramlining actuator with a fluid connection to the coulter actuator and a tramline marker operated by a fluid operated marker actuator with a fluid connection to the tramlining actuator so that it operates to make a mark during tramlining.

2. A drill as claimed in claim 1 in which the marker actuator has fluid connections to the coulter and tram lining actuators as as to operate in response to the pressure supplied to each, the press ure to the coulter actuator controlling the marker so that it can operate only when sowing, and then operating in accordance with the pressure supplied to the tramlining actuator so that it marks only when tramlining.

3. A drill as claimed in claim 2 in which the coulter actuator operates against spring pressure to urge the coulter into engagement with the ground and the tramlining actuator operates against spring pressure to open the seed shutter for sowing, a tramline control mechanism being provided that effects tramlining by blocking the pressure supply from the coulter actuator to the tramlining actuator through said fluid connection therebetween.

4. A drill as claimed in claim 3 in which the marker actuator operates against spring pressure to urge the marker into engagement with the ground, and in which the pressures supplied to the coulter actuator and tram lining actuator act against one another in the marker actuator so that a fall in the pressure supplied to the tramlining actuator to effect tramlining causes the pressure supplied to the coulter actuator to predominate and cause marking.

5. A drill as claimed in claim 4 in which the marker actuator comprises a piston and cylinder with said pressures supplied to the coulter and tramlining actuators acting on opposite sides of the piston in the marker actuator.

6. Tramlining and tramline marking apparatus comprising a fluid operated tramlining actuator that is adapted to operate a seed shutter of a drill in response to fluid pressure from a fluid operated coulter actuator of the drill, a tramline marker, and a fluid operated tramlining actuator with a fluid connection to the tramlining actuator so that it operates to make a mark during tramlining.

7. Apparatus as claimed in claim 6 in which the marker actuator has fluid connections to the coulter and tramlining actuators so as to operate in re sponge to pressure from each, the pressure from the coulter actuator controlling the marker so that it can only operate when sowing, and then operating in accordance with the pressure from the tramlining actuator so that it marks only when tramlining.

8. Apparatus as claimed in claim 7 in which the marker actuator operates against spring pressure to urge the marker into engagement with the ground, and in which the pressures from the coulter and tram lining actuators act against one another in the marker actuator so that a fall in the pressure from the coulter actuator to predominate and cause marking.

9. Apparatus as claimed in claim 8 in which the marker actuator comprises a piston and cylinder with said pressures from the coulter and tramlining actuators acting on opposite sides of the piston in the marker actuaton

10. A drill fitted with tramlining and tramline marking apparatus substantially as herein described with reference to the accompanying drawings.

11. Tramlining and tramline marking apparatus substantially as herein described with reference to the accompanying drawings.