Plough

This invention is a plough consisting of at least two booms pivotally connected together about a joint which can be locked to enable the booms to extend in line with each other, each carrying plough shares extending to one and the other side of the tractor so that a very large number of shares can be pulled by a single tractor. The pivot joint can be released to enable one boom to swing in relation to the other when not ploughing so that the total width of the tractor and plough is not too great to be driven along roads and through narrow openings into fields and so on. There may be boom at the other end of the fixed boom capable of pivoting about a similar joint towards the tractor. The one boom is arranged to be mounted on the tractor three point linkages so that it can be lifted by that linkage when not ploughing, and the other, or other booms can have wheels associated with jacks for lifting the shares clear of the ground enabling the wheels to run over the ground when not ploughing.

BACKGROUND OF THE INVENTION 
This invention relates to ploughs and one object is to provide a 
construction of plough enabling a large number of furrows to be ploughed 
at one pass from a single tractor. 
SUMMARY OF THE INVENTION 
According to the present invention a plough comprises two booms each 
carrying plough shares, the boom being pivotally joined at adjacent ends, 
one boom having a frame enabling it to be carried on the rear linkage of a 
tractor while the second boom has a depth controlling device at the end 
remote from the pivot. 
Preferably the arrangement is such that when the one boom is supported on 
the tractor linkage points, the pivot is generally in line with the 
fore-and-aft axis of the tractor. 
The one boom and its frame are preferably arranged so that when supported 
from the tractor the one (or front) boom extends somewhat to one side of 
the tractor, while the rear boom when in line with the front boom extends 
approximately an equal amount to the other side of the tractor. That means 
that the drag on the tractor is generally controlled so that it does not 
tend to cause the tractor to `crab`. Also the tractor never has to run 
over furrows, but a second set of furrows can be ploughed with the tractor 
running over unploughed land. This enables a powerful tractor to be used 
and advantage to be taken of the full tractive effort provided by its 
large wheels. 
Preferably there are means for locking the pivot so that during use it 
provides a rigid joint between the booms at least for turning about a 
vertical axis. 
There may be a depth controlling wheel at the front of the front boom but 
it will generally be possible to lift the shares on the front boom when it 
is desired to turn the plough by operation of the tractor linkage. 
There may also be a power actuator between the tractor linkage and the one 
boom for adjusting its position in relation to the tractor. 
The depth control device is conveniently a wheel which may be mounted on a 
hydraulic jack to be used for lifting the shares from the ground or 
allowing them to be inserted in the ground ready for ploughing. Such a 
wheel could have two positions, one of which will be generally parallel 
with the fore-and-aft axis, that is to say the direction of movement 
during ploughing while the other is generally parallel with the line of 
the boom so that the boom can be towed when not used for ploughing when 
not used for ploughing in a straight line behind the tractor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to the drawings, wherein like reference numerals designate 
identical or corresponding parts and more particularly to FIG. 1 thereof, 
the plough consists of three booms 10, 11, 12, each of which is built up 
from a desired number of similar standard boom sections carrying one 
plough share 13. In the example being described the booms have 
respectively five, ten and five shares 13, making in all twenty equally 
spaced shares. The booms are joined at universal joints 14 which prevent 
any movement about a vertical axis, or about the boom axis during 
ploughing, but permit relative movement about a horizontal axis transverse 
to the boom to allow for variations in the level of the field. 
The middle boom 12 is carried on frame work 15 mounted to slide under the 
control of a hydraulic actuator 19 transversely along a frame 20 carried 
on the three point suspension 16 of the tractor, and there is a small 
wheel acting as a depth gauge at 17. 
At the rear of the rear boom 11 is a wheel 18 which can be set by a 
hydrualic actuator 31 either at a height to lift the shares 13 from the 
ground or to have them in the ground at a predetermined depth. Also it can 
be manually or hydraulically operated so that the wheel is in a 
fore-and-aft plane as shown in FIG. 1 for use when ploughing or 
alternatively is in a vertical plane containing the axis of the boom for 
use when carrying the plough along a road or along a field not being 
ploughed. 
It will be observed that there is an equal length of boom on either side of 
the fore-and-aft axis 32 of the plough, and this means that the drag on 
the tractor is centralised, and the tractor does not tend to skew or crab. 
The front boom 10 has a guide wheel 33 which can be guided to run along the 
end furrow 34 which has just been ploughed, and a steering connection 35 
is coupled to the tractors front wheels 36 so that steering of the tractor 
keeps the wheel 33 in the furrow. The wheel has an actuator 31 for lifting 
its shares. 
After one set of furrows has been ploughed, the tractor can be turned after 
lifting the shares by use of the three-point suspension 16 to lift the 
middle boom 12 and the actuator 31 to lift the front and rear booms. Thus 
the plough then runs over land which has not previously been ploughed. 
This means that a modern 200 horspower tractor with large wheels can be 
used and running over unploughed land that can plough one furrow for every 
10 horsepower provided the drag is reasonably centred on the axis 32. Of 
course the actual number of shares will depend upon the particular 
requirements, but the booms can be built up to the required size and will 
always have an approximately equal extent to right and left of the 
tractor. The pivot point 14 is generally in line with the fore-and-aft 
axis of the tractor. 
For use on the road the wheel 18 is set into a vertical plane containing 
the boom 11, the wheel 33 is released from its steering connection, and 
the joints 14 are released so that the booms 10 and 11 can turn in 
relation to the boom 12 as shown at 37 and 38 and in FIG. 3, to give a 
total width of tractor and plough which is merely the width of the tractor 
plus the part of the boom 12 to its right which is considered to be an 
acceptable width for most roads. 
The pivots are generally similar. FIG. 2 shows how the rear pivot 14 has 
upper and lower ball joints vertically, one above the other, and each 
having one connection as a part of each boom 11 and 12. At the top the 
connection to the ball joint is through a lost motion connection 42 to 
allow movement about the axis 43. 
A rod 44 extends from a connection 45 on the frame 15 to a sliding joint 46 
on the rear boom 11. When a catch is engaged, the joint 46 cannot slide 
and the booms are held in line, but when the catch is released by a line 
48, sliding is permitted so that the boom 11 can turn to be along the axis 
32 for use on the road. 
The arrangement at the front pivot 14 is similar. It is also useful to 
release the pivots 14 to give a tight turning circle at the end of the 
line of ploughing so that the headland is no greater than normal. The 
shares are lifted, the rear joint 14 released by the line 48 and the 
tractor turns into the headland. The booms 11, and 10 are lowered, the 
front joint 14 locked, the line 48 released, and the tractor started. As 
the rear boom 11 turns into line with the front boom, the catch re-engages 
and the booms are held aligned through the next line of ploughing. 
For use if the front boom does not extend to the level of the tractor's 
front wheels, the offside front wheel of the tractor is mounted on an 
extensible axle 51 so that it can be extended to be in line with the front 
of the front boom 10 as shown at 36' in FIG. 4. Then the tractor can be 
steered so that the extended front wheel runs in the end furrow previously 
ploughed and the spacing of the new furrows can be easily maintained, 
without the driver having to look over his shoulder at the leading share.