Improvements in Machine Diggers
Year: 1893

page_text: Date of Application, 18th Feb., 1893-Accepted, 15th Apr.,
1893
COMPLETE SPECIFICATION.
Improvements in Machine Diggers."
. I, George GATTON Melhuish Hardingham, of 191, Fleet Street, in the
City of London, Civil Engineer and Chartered Patent Agent, do hereby declare
the nature of this invention (a communication to me from abroad from Andreas
Mechwart, of Buda Pesth, in the Kingdom of Hungary and Austrian Empire,
Works Manager,) and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
This invention consists of improvements in machine diggers; that is, diggers
forming part of or actuated by steam and other engines.
A machine digger constructed in accordance with this invention comprises
revolving shovels, by means of which the ground is broken and turned up. The
shovels are fixed to a revolving shaft, and cut, break and turn over the clods.
Any suitable number of shovels can be mounted on the revolving shaft. In some
cases, however, only one shovel need be used.
In the accompanying drawings,
Fig. 1 is a side elevation of a steam traction engine fitted with the improved
digger.
Fig. 2 indicates the way in which the clods are turned over by the digger.
Fig. 3 is a plan corresponding with Fig. 1, but shewing a modification of the
shovels.
The shovels B revolve in the direction indicated by the arrow in Fig. 1. The
cutting edges of the shovels may be placed either parallel to the axis of the shaft
on which they are mounted, as in Fig. 1, or spirally, as in Fig. 3. The spiral form
gives a more gradual cutting action, and puts therefore less stress on the machine.
The shovels are curved; the curve inclining from the cutting edge toward the axis
of the shaft. The amount of curve given to the shovels corresponds with the
forward motion of the machine during the cutting of one clod; that is, the distance
from the back edge of a shovel to the circle described by the cutting edge is equal
to the forward motion of the machine during the time required for cutting and
turning one clod. Consequently, when the shovels are cutting the ground, they do
not hinder the forward motion of the machine.
Fig. 2 shews how the clods lie after being cut by the revolving shovels and
turned over. The position which, theoretically, the clods should take is represented
at S, but in practice they fall into the position illustrated at S' on account of their
being broken by the shovels.
In order to properly break and turn over the clods, the shovels must be curved
more than is required for the forward movement of the machine.
To prevent the cut clods from being carried round by the revolving shovels,
there is a scraper or knocker-out P fitted to the rear of the framework carrying
the shaft on which the shovels are mounted. For exact working, the scraper
should have a radial motion imparted to it on account of the curve of the shovels,
but a moving scraper is not shewn, because it would make the machine too
complicated.
The forward movement of the machine, as well as the revolving motion of the
shovels, may be imparted in various ways. The machine may be drawn by draught
animals, or pulled by a wire rope from a winding engine at either end of the field,
like a steam-plough. The shovels may be rotated from the wheels by means of
gearing similar to that employed in mowing machines. The engine for working
the digger may be driven by steam, gas, oil, hot air, compressed air, or electricity.
In the machine shewn in the drawings, steam is the source of motive power; the

page_text: engine on the top of the boiler driving the machine forward by suitable gear-
wheels and chains K' and K', and also driving the shaft W, which, by means of
gear-wheels at each end, rotates the shaft carrying the shovels.
In order not to have the whole strain of driving the shovels passing through the
chains K and K', two auxiliary cylinders G¹ and G' are fitted to the side-frames Q¹
and Q; the piston-rods being coupled directly to the shaft W. In this case, the
chains keep the relative speed between the forward motion of the machine and the
revolutions of the shaft carrying the shovels constant. The steam is conducted to
and from the cylinders G and G' through flexible steam pipes.
The frames Q and Q' are journalled on the ends of the shaft W, so that the
shovels can be lowered or raised by means of the lifting gear H according to the
depth of cut required. In Fig. 1, the shovels are shewn raised in full lines and in
the cutting position in dotted lines. The lifting gear consists of a worm and worm-
wheel worked by a handle. The lifting chain is fastened to the framework at h. A
chain is used so that, when any abnormal strain comes on the shovels, they may be
free to rise and clear themselves.
Revolving shovels can be placed at both ends of the machine; the front set
being raised while the back one is down, and vice versa, so as to avoid turning the
machine when it has arrived at the end of a cut.
m
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
1. A revolving digger mounted on a traction or self-propelling engine,
constructed and operating substantially as described with reference to the accom-
panying drawings.
2. A revolving digger having shovels formed and operated substantially as
herein described, so that they offer no impediment to the advance of the machine.
3. A revolving digger having shovels so formed and operated that they offer no
impediment to the advance of the machine, the cutting edges of the shovels
inclining away from the axis of the shaft whereon they are mounted, and in which
the shovels themselves are kept clean by means of a scraper, substantially as herein
described.
4. In a revolving digger, the employment of a scraper arranged substantially as
described with reference to the accompanying drawings and operating to prevent
the clods of earth being carried round by the revolving blades.
5. In a revolving digger of the kind herein referred to, mounting the shaft
carrying the shovels so that it can be raised or lowered, the said shaft being con-
nected to the gear by a chain in order to permit the shovels to rise and clear
themselves under an abnormal strain, substantially as described.
6. In a revolving digger, the employment of shovels having their cutting edges
arranged spirally, substantially as described with reference to Fig. 3 of the accom-
panying drawings.
Dated the 18th day of February 1893.