GB2129265A

GB2129265A - Mowers

Info

Publication number: GB2129265A
Application number: GB08326779A
Authority: GB
Inventors: Anthony Leonard Turner
Original assignee: TURNER INT
Current assignee: TURNER INT
Priority date: 1982-11-02
Filing date: 1983-10-06
Publication date: 1984-05-16
Also published as: GB8326779D0; GB2129265B

Abstract

A mower of the kind having a cutting head mounted on the end of a whole series of arms which are arranged to be varied in angle one with respect to the next so that the mower can follow the contour of ground which varies in relation to that on which the tractor runs as well as cutting a swath at a variable distance from the tractor, has probes provided at each end of the cutting head connected in electric circuits for controlling the actuating hydraulic fluid supply to the individual rams so as to give near automatic control of the cutting head. <IMAGE>

Description

SPECIFICATION Mowers This invention relates to mowers of the kind in which the cutting head is mounted on one end of a system of arms of which the opposite end is connected to a tractor, with hydraulic rams to vary the relative angles of the parts.

In BP.1 156452 the cutting head is arranged to "float" and has wheels or skids at each end so that it can follow the contour of the ground in movement of the tractor. A probe is provided at the outer end of the cutting head to contact the ground, and is connected by a hydraulic circuit to operate a control valve at the tractor end of the complete unit and vary the flow of hydraulic fluid to the ram which is located between the tractor and the adjacent end of the arms so that effectively it causes raising or lowering of the complete system of arms and hence the cutting head. In an alternative described in said patent probes may be provided at each end of the cutting head and one of them will control the said tractor end ram and the other will control the one between the outer end of the arm and the head instead of allowing the head to float.

In practice the arrangements described in said patent 11 56452 have been found to be expensive and inefficient. The object of the invention is to provide improvements.

According to the invention the cutting head of a mower of the kind referred to is provided with at least one ground contacting probe arranged to operate an electric switch connected in a circuit including a hydraulic valve controlling the flow of hydraulic fluid to an appropriate ram in the system.

One presently preferred embodiment of the invention is now more particularly described with reference to the accompanying drawings in which: Figure 1 is a rear elevation of a mower; Figure 2 is a fragmentary view of the same on an enlarged scale.

Referring to the drawings, the mower extends laterally from the tractor and comprises a first arm 10 pivoted to the tractor and having a second arm 12 pivoted to it. The cutter head 14 is pivoted to the free end of the arm 1 2. A first ram 1 6 extends between the tractor and the arm 10 so as to control the angle of the same, and it will be seen that contraction of the ram 1 6 swings the arm 10 clockwise about its pivot on the tractor and thus tends to lift the cutter head 14.

A second ram 1 8 extends between the first arm and the second arm, and extension of ram 1 8 tends to pivot the arm 12 clockwise about the first arm and also tends to lift the cutter head. A third ram 20 is arranged to turn the cutter head 14 about the axis of shaft 22 for the purpose of maintaining the cutter head generally parallel to the slope of the ground.

In the illustrated embodiment a probe 30 is provided at one end of the cutter head and a similar probe 32 at the opposite end of the same (see Figure 2). Each probe is arranged to operate an electric switch in the associated housing 34, 36 and the switches are connected by appropriate conductors to a control valve unit located generally in the position indicated by the arrow 38 Figure 1 for operation (also) by the tractor driver.

Thus driver operated valves are used to control flow to the individual rams 16, 18, 20 and the electric control via switches 34, 36 may be arranged so that the driver can override the electric displacement.

It will be appreciated that in the circumstances shown in Figure 2 where probe 30 contacts the ground and probe 32 does not, the signals sent will be such as to cause actuation of ram 20 to turn the cutting head clockwise. If this takes both probes clear of the ground, the signal sent then will be such as to contract ram 1 8 and or extend ram 1 6 so as to return the cutting head closer to the ground, and if and when both probes are in contact with the ground the signal sent may be such as to reverse the effect of rams 16 and 1 8.

However, constant adjustment of position or "hunting" is undesirable and the probes and switches are preferably arranged so that when both probes contact the ground lightly, no signals are sent.

Instead of using the probes and switches to send electrical signals to the location indicated by the reference numeral 38, the probes may be directly connected to solenoid valves at each end of each ram, generally to like effect.

The substitution of electric control circuits instead of hydraulic control circuits is particularly advantageous in a system having parts which are moved to different angles, since it avoids the necessity for flexible pipes, joints and the like.

Moreover the system can act much more rapidly leading to the possibility of effectively automatic control of the cutting head, leaving the driver free for driving the tractor.

The probes are only shown diagrammatically on Figure 2 in that if constructed and arranged exactly as shown they might be vulnerable to damage. It is therefore preferred to substantially enclose the probes within the structure of the cutting head with only the operative tip exposed for ground contact, or possibly to arrange the probe to be acted upon by a ground-engaging skid, with a part of the skid pivoted for ground deflection, and then acting upon the probe correspondingly.

1. A mower of the kind referred to having the cutting head provided with at least one ground contacting probe arranged to operate an electric switch connected in a circuit including a hydraulic valve controlling the flow of hydraulic fluid to an appropriate ram in the system.

2. A mower as claimed in Claim 1 wherein such switches are provided at both ends of the cutting head.

3. A mower as claimed in Claim 1 or Claim 2 wherein a set of control valves are provided on the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Mowers This invention relates to mowers of the kind in which the cutting head is mounted on one end of a system of arms of which the opposite end is connected to a tractor, with hydraulic rams to vary the relative angles of the parts. In BP.1 156452 the cutting head is arranged to "float" and has wheels or skids at each end so that it can follow the contour of the ground in movement of the tractor. A probe is provided at the outer end of the cutting head to contact the ground, and is connected by a hydraulic circuit to operate a control valve at the tractor end of the complete unit and vary the flow of hydraulic fluid to the ram which is located between the tractor and the adjacent end of the arms so that effectively it causes raising or lowering of the complete system of arms and hence the cutting head. In an alternative described in said patent probes may be provided at each end of the cutting head and one of them will control the said tractor end ram and the other will control the one between the outer end of the arm and the head instead of allowing the head to float. In practice the arrangements described in said patent 11 56452 have been found to be expensive and inefficient. The object of the invention is to provide improvements. According to the invention the cutting head of a mower of the kind referred to is provided with at least one ground contacting probe arranged to operate an electric switch connected in a circuit including a hydraulic valve controlling the flow of hydraulic fluid to an appropriate ram in the system. One presently preferred embodiment of the invention is now more particularly described with reference to the accompanying drawings in which: Figure 1 is a rear elevation of a mower; Figure 2 is a fragmentary view of the same on an enlarged scale. Referring to the drawings, the mower extends laterally from the tractor and comprises a first arm 10 pivoted to the tractor and having a second arm 12 pivoted to it. The cutter head 14 is pivoted to the free end of the arm 1 2. A first ram 1 6 extends between the tractor and the arm 10 so as to control the angle of the same, and it will be seen that contraction of the ram 1 6 swings the arm 10 clockwise about its pivot on the tractor and thus tends to lift the cutter head 14. A second ram 1 8 extends between the first arm and the second arm, and extension of ram 1 8 tends to pivot the arm 12 clockwise about the first arm and also tends to lift the cutter head. A third ram 20 is arranged to turn the cutter head 14 about the axis of shaft 22 for the purpose of maintaining the cutter head generally parallel to the slope of the ground. In the illustrated embodiment a probe 30 is provided at one end of the cutter head and a similar probe 32 at the opposite end of the same (see Figure 2). Each probe is arranged to operate an electric switch in the associated housing 34, 36 and the switches are connected by appropriate conductors to a control valve unit located generally in the position indicated by the arrow 38 Figure 1 for operation (also) by the tractor driver. Thus driver operated valves are used to control flow to the individual rams 16, 18, 20 and the electric control via switches 34, 36 may be arranged so that the driver can override the electric displacement. It will be appreciated that in the circumstances shown in Figure 2 where probe 30 contacts the ground and probe 32 does not, the signals sent will be such as to cause actuation of ram 20 to turn the cutting head clockwise. If this takes both probes clear of the ground, the signal sent then will be such as to contract ram 1 8 and or extend ram 1 6 so as to return the cutting head closer to the ground, and if and when both probes are in contact with the ground the signal sent may be such as to reverse the effect of rams 16 and 1 8. However, constant adjustment of position or "hunting" is undesirable and the probes and switches are preferably arranged so that when both probes contact the ground lightly, no signals are sent. Instead of using the probes and switches to send electrical signals to the location indicated by the reference numeral 38, the probes may be directly connected to solenoid valves at each end of each ram, generally to like effect. The substitution of electric control circuits instead of hydraulic control circuits is particularly advantageous in a system having parts which are moved to different angles, since it avoids the necessity for flexible pipes, joints and the like. Moreover the system can act much more rapidly leading to the possibility of effectively automatic control of the cutting head, leaving the driver free for driving the tractor. The probes are only shown diagrammatically on Figure 2 in that if constructed and arranged exactly as shown they might be vulnerable to damage. It is therefore preferred to substantially enclose the probes within the structure of the cutting head with only the operative tip exposed for ground contact, or possibly to arrange the probe to be acted upon by a ground-engaging skid, with a part of the skid pivoted for ground deflection, and then acting upon the probe correspondingly. CLAIMS

3. A mower as claimed in Claim 1 or Claim 2 wherein a set of control valves are provided on the tractor for driver actuation, and said electric circuit is connected to the same.

4. A mower as claimed in Claim 1 or Claim 2 wherein each ram is provided with one or more solenoid operated hydraulic control valves which are connected to said switches.

5. A mower substantially as described with reference to the accompanying drawings.