MECHANICAL EXCAVATORS
Year: 1884

page_text: "
I ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
IMPROVEMENTS
Engineer, do hereby declare the nature of the said Invention for
IN MECHANICAL EXCAVATORS" and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement :-
A is the main beam; B the second beam; C the third beam; D is a large roller
at the bottom end of the main and third beams; F is a roller at the upper end of
the third beam; G regulating screw for the bucket chain and friction block for the
second beam; H is the pivot for the second and third beams I bottom pivot of the
inain beam and third beam I bottom pivot of the movable pick frame. J top pivot
of the movable pick frame K guiding support for the pick drum L is the winch for
operating the chain M.
M adjusting chain. N'rods by which the movable frame is supported.
O roller for the raising and lowering chain of the pick cylinder with a set screw
at the upper roller, P link chain running on a wheel with crank below and another,
upper wheel, and serving to increase or diminish the extent to which the pick-
cylinder penetrates into the soil to be broken down.
Qpick cylinder R support of the pick cylinder and of the great shoot.
S great shoot for receiving the soil which has been broken down.
T second shoot leading the earth shot from the buckets to the trucks or great
moveable shoot. U rods ensuring the rigidity of the frame work carrying the
buckets. V trucks for the material that is broken down X trucks carrying the
mechanical excavator. Y engine Z hinged framing for the transmission of power
from the engine to the pick cylinder. A¹ upright for varying and maintaining the
angle of inclination of the main frame. This angle may be varied from 35° to 90°
by means of chains C operated by a winch. B counter stay. C¹ tightening
chains; D chain for retaining the triangle of beams E! chains for supporting the
shoots F wire rope or chain serving by means of pullies G¹ to raise or lower the
pick cylinder. G pulleys fixed upon the lower and upper pivots of the moveable
frame. H tightening_chains I door by which the excess of soil carried by the
buckets is removed. J ballast boxes (the ballast may if required be dispensed
with and a large roller be placed at the end of the upper pivoting rod of the
moveable frame end rest upon the top of the soil operated upon K' boxes for

page_text: storing the supply of coal and water required for the engine. L¹ roof for shielding
the wagons and engines. M¹ buckets. N¹ support of the smaller shoot. O' small
movable slides of the buckets and of the large receiving shoot. P¹ upper guide for
opening the buckets. Q¹ lower guide for closing the buckets and for altering the
position of the great shoot. R¹ support serving to regulate the opening of the
buckets. S¹ hooks maintaining the buckets uniformly open. Trollers for
diminishing the friction of the buckets against the guiding panels. U¹ roller on
the large shoot allowing the same to follow the guiding panels Q¹. V₁ endless
screw serving to transmit power from the engine to the wheels of truck X whereby
lateral motion of the entire apparatus is ensured. X' supporting or friction rollers
for supporting the pick cylinder on its guide. Y¹ foot board. Z fixed support for
the system Z. a picks b steeled points ensuring the perpendicular motion of the
framing Z in the soil to be excavated c system of friction rollers & friction rollers
of the link chain & chains or links of the buckets.
The excavating machine represented in the annexed Drawings consists of
9 beams or girders united in groups of 3 by angle-iron bracings. These beams or
girders a part of which, illustrative of their position relatively to one another and
to the buckets is shown in Figure 3, form a rectangular traingle the right angle of
which is at the lower end of the second girder.
The girders or beams consist of sheet iron, of 0.01 to 0.02m thickness connected
by angle irons and carrying the rails on which run the rollers of-the-buckets.
At each corner of the triangle of girders there is a large roller D E F (Figure 1).
which serve to facilitate the rolling motion of the chain of buckets upon the girders,
the roller D is fixed on its arbor (Figure 6) and supported by a segment of cast iron
(Figure 8) having its centre on said arbor and also carrying the main-beam or
girder and the smallest beam.
The segment is supported upon the truck X by rollers. By this construction the
whole apparatus is made readily moveable round the centre of the segment and by
means of the roller D. The cast iron sector by means of its rollers runs on a
concave part fixed on the truck X which is of the same curvature as the segment
and thus it is movable round its centre and with it move the main beam and
small beam which swing on pivots I fixed on the sector. The framework by the
screw G may be set whereby the chain is rendered rigid. The triangle is held
quite rigidly by the rods U. and the three rollers D (Figure 6) E. F, (Figure 7)
retain all their freedom of motion round their centre and on their axles; whatever
the incline at which the excavator is set. This arrangement is moreover intended
to suppress the considerable friction which in certain cases would be produced upon
the arbors of the rollers by reason of the great tension of the chain of buckets and
the weight of the triangle of beams.
The rollers O Figure 9 serve to move a link chain which by a cord F fixed
thereto, alternately lowers and raises the pick cylinder.
The bucket chains are of wrought iron and in each of the "male" links is fitted
a steel thimble of 5 m/m thickness which can readily be replaced when worn each
"female" link is fixed to the bucket at one side (Figures 3. 4. 5) carries a roller f
which supports the chain of buckets and which by means of rails allows that the
buckets follow the beams without appreciable friction.
The link chain for the small guiding rollers Figure 10, is similar in its
construction to those for the buckets but is without friction rollers and of less
dimension; it carries an eye g which allows the rope F', which exerts traction upon
the pick cylinder to be attached thereto.
This chain is rendered rigid by a tightening screw firmly connected with the
upper guide roller and serving to increase or diminish the distance of the latter
from the bottom roller.

page_text: The buckets Figure 4 consist of a frame connected with the bucket chain and
capable of containing the bucket properly so called constructed of iron plates
of 3 thickness with angle irons and fixed as may be convenient within or at
the top of the frame or at its bottom according as to whether the machine is to work
upwards or downwards. The bucket properly so called having about 400 litres
cubic capacity is by this construction made moveable around its lower or upper
part around which it may swing so as to receive the loose material when filling
videlicet when it slides along beam A and will automatically close on turning round
the roller D and will open and assume a vertical position when arriving at a
suitable point or at the top of the short beam C according to the arrangement of
the support R. In the whole of this travel the motion is facilitated by friction
rollers in the latter part thereof by those of the movable shoot T. The buckets of
which there may be say 66 form two series (each in this case consisting of 33)
actuated by two chains carrying the buckets and friction rollers for the same.
When constructed on the scale herein referred to, the apparatus is therefore capable
in a complete turn of the bucket chains of breaking down 26.4 cubic metres or in
round numbers 26 cubic metres.
It has above been stated that the roller D is moveable on the centre of its shaft;
this movement is imparted to this roller from the engine by means of gearing
arranged in the usual manner and at a convenient rate of speed. This roller by
carrying with it the bucket chains causes the upper rollers to revolve and facilitates
the giratory motion of the bucket chains the same takes place with roller () by
means of its link chain which in its alternating motion carries with it the traction
rope F for the pick cylinder; the up and down motion of the pick cylinder is
therefore ensured by the rotation of the rollers O.
The rotary motion of the pick cylinder is effected as follows. This motion is
communicated by means of a hinged framing Z consisting of two connected loose
pulleys placed upon the fixed supporting part Z (Figure 1). The two loose pulleys
transmit their motion to two other loose connected pulleys at the upper part of the
lever arm fixed upon the support but moveable on the shaft of the two first pulleys.
The pulleys of the lever arm transmit their movement to a loose pulley placed at
the end of the movable lever arm near the support of the pick cylinder (Figure 12)
the latter lever arm, fixed at the upper movable end of the first lever arm is like
the latter movable on the shaft of the loose pulleys which are there placed. The
last pulley which is connected with a gear wheel communicates its rotary motion
to the pick cylinder, this rotary motion being thus entirely independent from the
vertical movement of this cylinder.
This gearing for the rotary motion of the pick cylinder is completed for the
purpose of avoiding injury by shocks arising from exceptional resistance, say a
rock, or a big stone, by a friction wheel h which is more or less firmly united with
the last loose pulley and the gear wheel (Figure 12) two set screws k allow its
adbesion to be regulated as may be desired. This latter part of the transmitting
gear is moreover protected against concussion with the side walls of the cutting by
steeled points solidly fixed at the extension of the lever arm carrying the last loose
pulley which gradually loosen the soil in their vertical movement thereby ensuring
that the lateral motion of the apparatus be effected without excessive labour.
The pick cylinder consists (Figures 13 and 14) of a cylinder of sheet iron upon
the periphery of which are mounted in suitable holders hollow circles receiving the
wooden handles i. These handles or stems are held in position by screw collars at
their ends near the edge of the sheet iron cylinder. The bandles are placed in
pairs and symmetrically with relation to the centre of the cylinder and are parallel
to a diameter thereof. At one end they carry according to circumstances and the
nature of the soil picks or shovels or rather small rakes and at the other
hammers or steeled points m (Figure 13); by their arrangement the picks or
hammers or shovels and points, are intended to serve for completely loosening in
one complete turn of the pick cylinder all that part of the cutting which is in line

page_text: with the same and in front of the cylinder experience and practice will readily
show at what distance from one another the tools have to be for obtaining the best
results with regard to any given soil.
The pick cylinder is placed on a movable runner which, by the friction rollers X¹
slides without friction on the guiding support K. The runner is fixed on the
support R connected with the rope F. The support R moreover carries the
principal shoot for receiving the soil that has been broken down. The power
required for raising the pick cylinder can be further diminished by a counterweight.
The main shoot for the soil S. therefore follows the vertical movement of the
pick cylinder; it receives in all positions of the cylinder the soil broken down
thereby transmitting it to the buckets which it faces. The small movable slides 01
allow that the main shoot and the buckets be always in direct communication.
When the main shoot has arrived at the bottom of its travel, it is carried slightly
backwards by means of its roller U₁ sliding on guide Q, so that the pick cylinder
can descend to the bottom of the cutting without injury to the main-shoot. When
the pick cylinder rises again, the shoot, carried with the same will by reason of its
weight, and following the guide Q', gradually ro assume its former position with
regard to the slope of the cutting against which it has a tendency to bear and upon
which it slides by means of a bent iron (Fig. 1 and 2); a double steel edge may
however be employed instead and will leave no space whatever between the shoot
and the slope of the cutting. In stony soils however this steel edge may be drawn
back, or it may be made in movable sections, so as not to leave too great a space
between the shoot and the slope of the cutting.
The support which serves to regulate the opening of the buckets (Fig. 11) is
fixed to the small beam by cross shaped pieces consisting of iron bars movable
upon their greater sides and serving as rails upon which the rollers T¹ travel.
These rectangular bars are arranged like the slates on a roof, that is to say they
partly overlap and are independent from one another from top to bottom of
beam C and can, by a small hook be maintained in a vertical position. When in
this last named position they allow the buckets to open and assume the vertical
position on their diagonal. In this position the loose earth in the buckets is
directly emptied upon the second shoot conducting the same to the trucks V.
By means of the upright A' stayed by counter posts B' the main girder and
consequently the whole triangle of beams, may be placed in a position varying
from 35° to 90°, that is to say from the natural incline of heaped sand to the
vertical. The triangle of beams is maintained in the different positions which it
may occupy, by chains C rolled upon a winch which regulates the the inclination
and also by chain D' serving as a stay and being attached to the framing of the
trucks X gives greater stability to the apparatus as a whole.
The main beam or girder (Figs. 1 and 2) carries a frame movable on the pivots I
and J and carrying the pick cylinder. It may assume various positions as required
by reason of the inclination of the main beam and because the ends of the movable
frame should not touch the side of the cutting.
These various positions of the movable frame are regulated by the iron rods N
which support its upper and lower parts being themselves connected with a runner
borne by an adjusting chain M. Moreover a pitch chain P allows the distance
between the two greater sides of the frame to be reduced and thus to diminish or
increase the extent to which the breaking down tools enter into the earth in the
cutting.
The whole apparatus rests upon three trucks carried by 7 pairs of wheels of
which one, opposite to the cutting carries the locomotive and the ballast. The two
others support the segments of the lower roller and consequently the whole
triangular framework. The three trucks are firmly connected by I shaped rails
rigidly uniting the parts supporting the framework. A ballast box J' placed under
the locomotive truck allows the strain from the main frame to be counterbalanced
when the inclination is great; it may be observed that this ballast box may be
dispensed with and be replaced in some cases by a large roller placed at the upper

page_text: part of the movable frame and free to roll on the side of the cutting and bearing
thereon.
Under the other two trucks are coal and water boxes sufficing for the daily
supply of the machine.
The movable shoot which may if desired simultaneously fill all the trucks of a
train consists of a trough in which works an endless chain consisting of iron links
hinged to one another and furnished at certain distances with discs of wood or
sheet metal the shape of which corresponds to that of the trough these discs are
perpendicularly fixed at the centre of each link. This chain runs on the periphery
of two polygonal wheels placed at the two ends of the trough, the locomotive or a
special engine causes one of the wheels to rotate this carries the chain with it and
rotates the other wheel. Thus the endless chain having travelled round one wheel
passes above the trough and returns to its starting point viz. to the wheel driven
by the engine. When travelling above the trough the chain is supported by rollers
facilitating its motion. The trough itself is supported at suitable distances upon
iron testles, so that the trough may be moved in either direction that is, as
required by the line in the cutting on which the trucks run and according to the
limits of the cutting in which the excavating machine works. In the trough
apertures are provided over each truck these are closed by suitable slides operated
by a crank at the end of the trough so that the apertures may be closed more or
less allowing the whole or part only of the material brought by the endless chain
to pass so that only the first trucks will be filled or all will be filled simultaneously.
The slides may be made independent of one another. The trough may moreover
be inclined sideways or endways and be movable on that end which is nearest to
the excavating machine to which latter it may be moreover be attached.
The whole machine is so arranged that when it is taken apart the trucks
forming part thereof may also serve to transport all the parts on a line of rails.
Now when the machine arrives upon the spot where it is to operate it is set up as
shown in Figs. 1 and 2.
The engineer and the other necessary operatives being in their places, one
experienced man being at the winch for the chain P, the engineer at a given signal
starts the roller D the bucket chains are thereby set in motion. as stated the
roller acts upon the chains running thereon and the pulleys on the hinged
framing are set in motion and the pick cylinder is alternately raised to and
lowered from the top of the cutting and at the same time receives a rotary motion
of 100 revolutions per minute the picks or shovels and hammers or points are
alternately brought against the soil which is thereby attacked and broken-down.
To diminish the resistance to shocks which the machine may have to bear, the
tools are as stated mounted on wooden handles or stems. To prevent delay in the
working of the machine it is better to allow, when meeting a rock or other obstacle
one or even several of the tool-handles to be broken as they can readily be replaced
when the machine is stopped. By the rotary motion of the cylinder the earth or
stones which are broken down are easily driven back and the incline of the main
shoot carries the same to the buckets. These move from top to bottom; their
speed is 1/, or double of that of the cylinder (and consequently of that of the large
shoot) they in turn present themselves to the shoot. When the buckets arrive at
the bottom of the main beam A, their rollers strike against the guide Q¹ which
forces the buckets to close; these then pass around the roller D and rise in the
contrary direction upon the roller F. the buckets are kept closed by the support R¹
at a suitable moment and at such height as may be required by the bars which are
raised so that the rollers T of the bucket being unsupported, the inner bucket
assumes a vertical position in pouring the earth into the second shoot and thence
either into the large movable shoot and the trucks directly placed at the openings
of the same. The lateral movement of the machine is given by the engineer whilst
the operator at the winch P regulates the extent to which the breaking down tools
enter the soil.

page_text: The machine by reason of its constructions will produce great saving in work of
this kind; it allows the earth to be loaded into trucks either at the bottom, or at
the top of the cutting so that when the distances are not too great the whole may
be so placed that the full trucks pull the empty ones up. By duplicating the large
movable shoot as many trucks as desired may be simultaneously loaded. This
shoot moreover enables the material to be delivered either above or below the
delivery of the buckets or can be arranged to first raise and then lower the
material even to some distance from the work.
But little power is required for the pick cylinder as only 6 or 8 picks are
presented at a time and the actual work is done by having 5000 blows from picks
per minute. This work is continuous and without stoppage even when the machine
moves laterally.
The loose earth or material moves through the main shoot, the buckets and the
other shoots and into the trucks merely by its own weight; this power is greater
in a machine working at the top than in one working at bottom.
This machine has been so designed that the excavating is divided into three
distinct periods, viz.: the breaking down or loosening of the soil.
2) The charging of the buckets with the material.
3) The discharge from the buckets into the trucks, the object having been to
provide for one of these operations a special device fullfilling the following
conditions :-
1) A loosening tool that may be varied according to the nature of the soil.
2)-That-the-loose material may be carried away by troughs or buckets which
serve this end only.
3) For the purpose of keeping pace with the large quantities delivered by the
machine to provide means whereby all the trucks of a train may be simultaneously
loaded.
In seeking to fulfill these conditions the absolute necessity of making the
machine easily transportable by boat or rail has not been neglected. This is
obtained by so constructing the trucks that they may run on ordinary rails and
by such arrangement of the frame work and buckets that all parts together with
the engine may be transported on the trucks. In the tool it has been sought to
attain the effecting of a great amount of work in a given time by employing
centrifugal penetration which is much superior to the method of tearing off or
raising the material as customary in other apparatus of this class.
The Drawings illustrate a machine for working above the ground upon which it
rests and also a machine of a very large size as it can dig a trench of 12 metres
depth at one operation whilst machines hitherto built would require to make it in
two operations.
If this machine is to work below the soil on which it rests, it will have to be
modified as follows: A large beam or girder corresponding to A in the Drawing
(Fig. 1 and 2) is placed like beam C and is mounted on a pivot or shaft which
allows it to vary the slope of the cutting and by the same shaft it receives motion
from the engine. The buckets alternately. pass above and below this single girder,
being filled below and emptying at the upper part of the girder into trucks (The
opening of the buckets will therefore be above when they are below the girder.)
It is obvious that this girder is fitted with a movable shaft having a movable
frame which carries the breaking-down tool and shoot arranged as in Fig. 1; all
the operating parts are similar to those above described. The power of the engine
will have to be increased as the weight of the soil will aid it only to a very limited
extent.
For smaller cuttings the machine may be simplified and its construction
modified.
The two chains of buckets may be mounted at the end of a single truck instead
of at the centre (Fig. 2) the whole being lighter may swing round its centre so as
to be able to operate all round and at any angle.

page_text: Where very large cuttings are to be made and a height of 20 or 30 meters to be
operated upon at once, the machine is modified as follows: The girders B and C
are dispensed with. The great beam has one or two wheels bearing upon the side
of the cutting and carries one or two large shoots of suitable length. On the large
beam slides a carriage which is always horizontal and carries the pick cylinder and
an engine to operate it.
Behind the pick and following its upward motion is a small helicoidal shoot
conducting the sail into the large shoot and thence it passes to the trucks.
Suitable arrangement of the shoots allows several trucks to be filled simultaneously
with the earth broken loose even at the level upon which the machine stands. On
the trucks which carry the apparatus the engine is placed which actuates the
carriage and the girder or beam respectively. Suitable stops may be provided in
the shoots so as to break the fall of the earth and diminish the concussion with the
trucks.
The whole machinery may be moved laterally on rails.
The purpose for which the machine is intended affects therefore its construction,
form, size its capacity, and its cost without however affecting the leading features
and principles videlicet the pick cylinder, the receiving shoots worked as far as
may be by the weight of the material itself, the facility of filling the earth into
trucks and that the same requires only a light engine.
In the Drawings
Figure 1 is a front elevation.
Figure 2 half of longitudinal elevation.
Figure 3 section on a line perpendicular to the main girder and passing through
the bucket rollers.
Figure 4 elevation of buckets and chain (main girder).
Figure 5 plan of the links (main girder).
Figure 6 roller for the bucket chains.
Figure 7 roller for the bucket chains.
Figure 8 support of the main roller and girders.
Figures 9 and 10 roller and chain.
Figure 11 details of the device for opening the buckets.
Figures 13 and 14 section and view of the pick cylinder.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is :-
A mechanical excavator characterized chiefly by the following features:
1) The pick cylinder acting by centrifugal force.
2) The automatically opening and closing buckets.
3) The movable shoot for receiving the broken down or disaggregated material.
4) The combined action of the weight of the broken down soil or materials and
of the engine for raising the material into the trucks.
5) The large moveable shoot for simultaneously filling all the trucks of a train.
All substantially as and for the purposes set forth, and as indicated in the
Drawings.
1011
1004
ALFRED J. BOULT.
p. B. Dukes.