A NEW OR IMPROVED PLOUGH
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by William Edward Gedge at the
Office of the Commissioners of Patents, with his Petition, on
the 27th May 1870.-A communication from abroad by Pierre
Mathurin Tanvez, of 39, Faubourg St. Martin, Paris, France.
I, WILLIAM EDWARD GEDGE, of the Firm of John Gedge and Son,
of No. 11, Wellington Street, Strand, in the County of Middlesex,
Patent Agent, do hereby declare the nature of the said Invention for
"A NEW OR IMPROVED PLOUGH," a communication to me from abroad by
Pierre Mathurin Tanvez, of 39, Faubourg St. Martin, Paris, France,
to be as follows :—
All tillage of land has for object 1°, to make it as light as may be
desirable, 2°, to destroy the plants and parasitic animals, the baneful
influence of which often compromise harvests. These objects appear to
have been hitherto only imperfectly attained by repeated tillage with
ploughs, harrows, scarifiers, extirpators, and clod crushers, and it is
proposed by this Invention not only to effect a more perfect tillage, but
to do so at one operation. The ordinary plough cleaves the earth,
turns it over, but it cannot be said to divide it. What is requisite to
and

page_text: complete its work is to cut in a uniform and continuous manner through
the strip of earth raised by the share, and this is done by the screw
plough the subject of this Invention. Like other ploughs it has a
coulter, a share, and a commencement of mould board which uplifts
the strip without turning it over; immediately behind this rudimentary
mould board is a screw similar to that of a steamboat, that is to say, six
or eight curved blades of steel held by a cast-iron disc on a shaft to
which a rotary motion is given
ада
CONTE
board when uputs
the strip without turning it over; immediately behind this rudimentary
mould board is a screw similar to that of a steamboat, that is to say, six
or eight curved blades of steel held by a cast-iron disc on a shaft to
which a rotary motion is given.
DESCRIPTION OF THE ACCOMPANYING DRAWINGS.
Fig. 1 is an elevation, and Fig. 2 a plan view of a plough made
according to this Invention.
A rigid frame A, A., is supported by three wheels, one in front and two
behind. At the side of this framing is placed a slide C, C³, to which the
share and the coulter are fitted; an adjusting screw the crank handle of
which is at L sets this slide in motion and permits the share to be lowered
below the plane tangental to the wheels and thereby regulates the depth
of the tillage. The front wheel, smaller than the two others, pivots and
a beam causes it to follow the direction given by the driver to his team,
this wheel directs the plough precisely as the fore carriage guides a
four-wheeled vehicle. The hind wheels serve, firstly, to maintain the
equilibrium of the machine in lieu of the man holding the plough
handles of ordinary ploughs; secondly, to set the screw in motion by
means of straight and bevilled toothed gearing S, S. As the resistance
to sliding is the origin of the working of the screw the wheels of the
hind carriage are furnished with projections to ensure their adhesion to
the soil. These wheels in rotating give motion to the axle, the toothed
gearing and consequently to the screw, the number of strokes of which
is in proportion to the distance traversed, twenty-five to thirty strokes
per yard brings the land to a very sufficient degree of lightness, but the
number of these strokes might easily be increased for any special purpose
such for example as the destruction of the grub or white worm. The
hind wheels are not keyed on their shaft, but in communication with it
by clicks and ratchets in such wise that the driving wheels carry their
axle with them only in the forward movement and not in any retrograde
motion. This arrangement permits the machine to turn on itself and
to follow all the sinuosities of the ground, even in turning the share
raises its strip of earth and the screw does not cease to chop it.

page_text: To explain this effect it should be remarked that in the turn one of
the driving wheels moves backward and the other forward, the retrograde
movement of the one as before stated has no effect, whereas the forward
movement of the other actuates the screw always in the same direction.
When the machine resumes a straight course the two driving wheels
mutually assist each other. The point of contact of the straight toothed
wheel with its pinion governs the position of all the driving parts from
this point to the screw. This point of contact is regulated, 1°, by the
radius of the wheels of the hind carriage; 2°, by the dimensions of the
screw; 3°, by the average depth to be given to the tillage. If the strip
of earth raised by the share should have a depth of eight inches or more
the blades of the screw will be from 14 to 18 inches from centre to
point. If the blade were less one of two things would occur, either that
the strip of earth would not be entirely cut through by the screw, or
that it would strike against the disk carrying the screw blades. Increasing
the length of the screw blades beyond 18 inches would be to increase the
resistance without corresponding advantage elsewhere. If the cultivation
does not require the earth to be dressed to the full depth, the screw may
be supplied with other blades which would act only on a third or half of the
raised strip. The front bearing of the screw shaft might even be raised
by wedges, or otherwise the bevil wheel and pinion would still gear and
the screw accomplish the desired work.
When the machine is travelling to the field the projections on the
driving wheels are removed, as also the screw, and the share and coulter
are at the highest points to which they can be raised by the play of the
slide C, C. When the machine is to work the first thing to be done is
to cause the share to enter the ground, for this purpose the plough is
momentarily drawn forward, and the crank L being at the same time
turned the slide forces the share to make the first cut in the same manner
as the slide of a parallel lathe carries the tool forward and makes it cut
the piece presented to it. The share being entered to the desired depth
the screw is screwed on to the end of its shaft, the driving paddles arc
fixed on the wheels, and the toothed gearing set free, if it has been
stopped by a clutch or brake arrangement during the journey to the field,
finally the team is driven on, and the machine is in complete action.
The screw being immediately behind the share it follows that this
latter will receive all the shocks if any. The share and the partially
developed mould board bring the strip of the earth within reach of the
strokes of the screw so that the strip would be traversed to a great

page_text: extent even if the blades of the screw did not descend to the earth line.
This position of the half uplifted strip is very advantageous to the
working of the screw, the strip being divided with the least possible effort.
It might have been feared that the screw would become clogged with
weeds as happen to the screws of steamboats, because they move always
in a same resisting medium, but here on the contrary the screw after
having passed through the strip of earth continues through the air of
its rotation and the centrifugal force assisting frees itself from the weeds
which may have caught in it.
When the share meets with rock it has a tendency to rise of itself and
slide over it, and in any case it might be aided by pressing on a lever
placed at the tail of the plough in the position of the ordinary plough
handles, the power of this lever added to the draught of the horses would
cause the front of the machine to rise by making it pivot on the axle of
the hind carriage. In making ploughs for stony countries attention will
be specially fixed upon this point, and success will be the more assured
the better the weight of the machine is poised on the axle of the hind
carriage. If the share should meet an obstacle that even the pivoting
movement above described will not permit it to overcome it must be
lifted by the aid of the crank L.
It may be here observed that the slide carrying the share might be
worked by a rack in lieu of an adjusting screw. The adjusting screw
has the advantage of forming its own stop and of not turning under any
shock given to the share, which therefore necessarily remains at the
required depth, this advantage however becomes a defect in lands where
the share is likely often to meet with rock or stones at the ordinary
ploughing depth, and here the rack has the advantage of sensibility; like
the screw it will cause the share to enter the ground to the required
extent, but to keep it at this depth a stop is required, and if for stop a
weight is applied on the crank a sort of safety valve is obtained against
the possible causes of breakage to which the share is exposed. The weight
which resists any movement of the rack keeps the share at a proper
depth so long as the resistance remains within a certain limit, but this
once exceeded the share will rise of itself. This effect will be readily
understood when the share is working the resistance or strain upon it has
two compartments, the one horizontal, which will be borne by the slide
or slide bar of the share holder, the other vertical, bearing on the rack,
and finally on the crank, becomes horizontal instead of vertical as in the

page_text: case of the adjusting screw. So long as the share meets only arable land
it will remain at the desired depth because the weight applied on the
the crank will have to be regulated thereto, but if on the contrary
the share meets with rock the vertical component increases, and as
the weight which is to resist it remains the same the share will rise,
turning the crank until the strain upon the share will have come
back to its normal amount, that is to say, to the resistance given by
arable land. The crank will bend towards the back of the machine so
that the labourer may by turning it more or less vary the depth of the
ploughing without having to stop the team for that purpose. The
draught is on the hook B. The rod R regulates the vertical position of
the point of traction, the piece T which supports the rod R may travel
along the cross beams V, V. This movement may be regulated by a
screw which while permitting the displacement of the point of traction
even with the team in motion is also useful as an aid although not as an
indispensable adjunct when it is desired to make the machine turn on itself.
Solidity and lightness are terms which apparently preclude each other,
but which nevertheless must be brought into account; this is a difficulty
attaching to the ordinary plough from which this screw plough escapes.
This capital point is explicable in two ways, the first is that this plough
is not worked by manual labour, the second is that it rolls instead of
sliding along like ordinary ploughs, now the difference of the coefficient
of rolling and sliding is such that it is as easy to roll 10 cwt., as to drag
1 cwt. It is only fair to admit that the projections on the periphery of
the hind wheels to some extent resist the rolling, but on the other
hand the power thus absorbed is not lost because they contribute their
part in dividing the land. It is also true that these projections may
constitute an appreciable passive resistance if a suitable shape and
position be not given to them. That illustrated on the accompanying
Drawing is that which is at present deemed the most advantageous.
The dimensions, length, breadth, and thickness of these projections may
vary according to requirement but the projection should in every case be
sharp on one side in order that it may more easily enter the ground and
obtuse on the other, the better to resist any tendency of the driving
wheels to slide instead of roll along.