Improvements in Excavators.
Year: 1895

page_text: Date of Application, 8th Oct., 1895
Complete Specification Left, 30th June, 1896-Accepted, 1st Aug., 1895
Improvements in Excavators.
I ALEXANDER MCDONALD, of 643 Mount Auburn Street, Cambridge in the
County of Middlesex and State of Massachusetts, United States of America,
Marble and Granite Dealer do hereby declare the nature of this invention to be
as follows:-
The object of my invention is to provide an improved excavator and dredger
designed for making tunnels, canals, ditches &c., with a comparatively small
expenditure of power.
The improved excavator is mounted on a wheeled carriage on the rear end of
which are erected guide ways in which is fitted a slide adapted to be fixed to the
guide ways after being vertically adjusted to the desired position. To the lower
end of the slide is hinged a frame mounted to swing up and down between the sides
of the carriage and carrying revolving picks and an endless carrier of the bucket
and chain kind arranged in the rear or below the said picks, so that the material
cut and loosened by the picks, falls by its own gravity into the buckets of the
carrier when the frame is swung upward.
In order to raise and lower the frame its free end is connected with a rope or
chain connected with a hoisting device on the front end of the carriage driven from
an engine which together with the boiler are also mounted on said carriage.
The revolving picks are preferably made in sets mounted upon two parallel shafts
journalled in the swinging frame and extending longitudinally thereof. Upon the
outer ends of the shafts are secured downwardly curved picks set at angles one to
another, so that the shafts when rotating in unison permit the prongs of the picks
to readily pass each other. Upon the shafts are further set any desired number of
horizontal picks held at suitable distances apart by intervening washers, the picks
of the one shaft alternating with those of the other. The succeeding picks on the
shafts are set at right angles to each other, whereby the shafts can be placed very
close to one another without the picks interfering one with the other. The inner
ends of the shafts are geared together, so as to rotate in unison and on the inner
end of one shaft is secured a bevel wheel in gear with a bevel wheel on a transverse
shaft journalled in bearings on the slide in line with the hinge joints. This cross
shaft carries a gear wheel in mesh with a pinion on a driving shaft journalled on the
slide and carrying a pulley connected by a belt with a pulley on the driving shaft
of the engine. Thus when the engine is set in motion rotary motion is imparted to
the cross shaft which in turn by the bevel gear wheels rotates the one pick shaft
which being geared with the other pick shaft cause the picks on both shafts to be
rotated in unison.
The endless carrier consists of a sprocket chain and buckets, the said chain
passing over sprocket wheels journalled in the front end of the swinging frame and
over sprocket wheels secured on a shaft turning in bearings at the rear or upper
end of said frame, and so geared with the driving shaft that when the latter is
rotated as previously described the sprocket chains will be set in motion and the
buckets filled by the picks will carry the material to the rear end of the machine
and discharge it into a waggon, chute or other suitable device.

page_text: In order to bring the picks and the front end of the carrier to the proper depth
in the ditch to be made it is necessary to vertically adjust the slide and for this
purpose the latter is provided on its front face with racks gearing with pinions on a
trausverse shaft turning in bearings on the guideways one end of which shaft
carries a gear wheel in mesh with a pinion on a shaft turning in bearings in one of
the guide ways and carrying a crank handle, by turning which the rack pinions will
cause the slide to move down or up in the guide ways, according to the direction in
which the handle is turned.
The slide is secured in position after adjustment by means of screws screwing in
the transverse bar which connects the upper ends of the guide ways.
In order to steady the swinging frame while swinging up or down, a rope or chain
is provided winding on the shaft of the hoisting device in an opposite direction
to the winding of the rope or chain used for raising and lowering the said frame.
This steadying rope extends over a sheave hung on a post projecting at an angle
from the frame, in a downward direction and is attached to the carriage. The
shaft of the hoisting device is geared with a pinion on a driving shaft having
forward and reversing pulleys connected by belts with similar pulleys on the
driving shaft of the engine.
When the machine commences to work, the swinging frame stands in a vertical
position, it having been fed downward the desired distance by the operator turning
the crank handle so as to impart a downward sliding motion to the slide as
previously described, after which the slide is fixed in position. The operator now
starts the engine and connects it with the hoisting device by the shifting lever,
whereby the picks are rotated and a travelling motion is imparted to the carrier
and an upward motion given to the swinging frame. The picks in this manner are
caused to cut into and loosen the ground which is discharged direct into the buckets
of the carrier by its own gravity and discharged at the top rear end of the frame.
The carriage may be moved forward at the same time so as to cause the revolving
picks to enter the ground to their full depth, so that a large amount of material is
cut and removed during one upward motion of the swinging frame. In this manner
a segmental cut is made in the ground from a vertical to an approximately horizontal
position assumed by the swinging frame.
After the cut is made the hoisting device is reversed so as to lower the swinging
frame again to a vertical position. The carriage is then again moved forward and
a new cut made as above described.
When the machine is arranged for tunnelling purposes, two sets of revolving
picks and endless carriers are provided on the swinging frame, similar to the one
set above described except that the shafts and carriers extend obliquely. The
swinging frame is in this case hinged upon a wheeled frame mounted to travel
transversely on a carriage adapted to be moved forward on rails laid in the tunnel
as the works progresses. The material discharged by the buckets of the two sets
of picks and carriers is conducted by means of a shoot onto an endless carrier
extending upwardly and discharged onto cars travelling upon the rails and conveyed
where required.
The machine besides its use for inaking ditches, canals, tunnels &c. may also be
used if desired for boring holes in the ground and in this case it is necessary to
swing the frame back of the perpendicular when lowering the slide so that the
picks will loosen the earth before the buckets come in contact with it. It is
necessary to keep the picks and buckets going all the time of coming back from
the horizontal to the vertical position. The buckets take up all the loose earth
that is spilled when the buckets are coming up so that each cut is cleaned before a
new one is commenced. In this arrangement the swinging motion of the frame is
imparted by gear wheels instead of by ropes and hoisting gear as before described.
For this purpose a gear wheel is mounted loose on the front shaft but attached to
an arm on the swinging frame. A pinion gears with this wheel keyed on a shaft
journalled in the frame and carrying a pulley connected by a belt with a pulley

page_text: adapted to be turned by hand or power as desired to impart an up and down
swinging motion to the frame.
Dated this 8th October 1805
A. M. & WM. CLARK.
Improvements in Excavators.
I, ALEXANDER MCDONALD, of 643 Mount Auburn Street, Cambridge, in the
County of Middlesex and State of Massachusetts, United States of America,
Marble and Granite Dealer do hereby declare the nature of my invention, and in
what manner the same is to be perforined, to be particularly described and
ascertained in and by the following statement :-
The object of my invention is to provide a new and improved excavator and
dredger designed for making tunnels, canals, ditches, etc., in a very simple manner,
and at a comparatively small expenditure of power.
The invention consists of certain parts and details and combinations of the
same, as will be fully described hereinafter and then pointed out in the claims.
Reference is to be had to the accompanying drawings forming a part of this
specification, in which similar characters of reference indicate corresponding parts
in all the figures.
Figure 1 is a plan view of the improvement as arranged for excavating and
dredging;
Figure 2 is a cross section of the same, on the line 2-2 of Figure 3;
Figure 3 is a side elevation of the same at the beginning of the work;
Figure 4 is a sectional side elevation of part of the improvement, showing the
picks at work;
Figure 5 is an enlarged sectional side elevation of the revoluble picks ;
Figure 6 is a sectional plan view of the same;
Figure 7 is an enlarged side elevation of the driving mechanism, the section
being taken on the line 7-7 of Figure 8;
Figure 8 is a rear end elevation of the same, with the carrier omitted;
Figure 9 is a side elevation of the improvement, arranged for tunneling; and
Figure 10 is an enlarged plan view of the same.
The improved excavator is mounted on a suitable wheeled carriage A, on the
rear end of which are erected the guideways B in which is fitted to slide vertically
the slide C adapted to be fastened on the guideways after being vertically adjusted
to the desired position, as hereinafter more fully described.
On the lower end of the slide C are arranged hinges C¹, see Figure 2, connected
with a frame D mounted to swing up and down between the sides of the carriage A,
as will be readily understood by reference to Figures 2 and 4.
This swinging
frame D supports revoluble picks E, and an endless carrier F, of the bucket and
chain kind, arranged in the rear or below the said revoluble picks, so that the
material cut and loosened by the picks E, falls by its own gravity into the buckets
of the carrier F at the time the frame D is swung upward.
In order to raise and lower the frame D, I connect the free end of the frame
with a rope or chain G extending upwardly and connected with a hoisting
device G¹ of any approved construction, located on the front end of the carriage A,
and adapted to be driven from an engine H, likewise supported on the carriage
together with the boiler for furnishing the necessary motive agent to actuate the
engine H.
The revoluble picks E are preferably made in sets, as illustrated in the
drawings, with particular reference to Figures 5 and 6, the said picks being
provided with two parallel shafts E¹, E³, journaled in suitable bearings on the

page_text: frame D, and extending longitudinally thereof. On the outer ends of the
shafts E¹, E2 are secured the downwardly curved picks E³, E, set at angles one
to another so that the shafts E', E' when rotating in unison permit the prongs
of the picks to readily pass each other. Upon the shafts E1, E2 are further set
any desired number of horizontal picks E, E respectively held at suitable
distances apart by intervening washers E', and with the picks E' of the shaft E¹
alternating with the picks E. The succeeding picks on the shafts are set at
right angles to each other, as illustrated in Figure 6, whereby the shafts E¹, E'
can be placed very close to one another without the picks of the two shafts
interfering one with the other.
On the inner ends of the shafts E', E' are secured gear wheels E8, E' in mesh
with one another, so that when one shaft is rotated, the other shaft rotates in
unison with it. On the inner end of the shaft E', see Figure 2, is secured a bevel
gear wheel I in mesh with a bevel gear wheel 1', secured on a transversely
extending shaft 12 journaled in suitable bearings on the slide C in line with the
joints of the hinges C₁. On this shaft 12 is secured a large gear wheel [ in mesh
with a pinion 14 fastened on a driving shaft I', journaled in suitable bearings on
the slide C, and carrying a pulley 1, connected by a belt 17 with a pulley H' on
the driving shaft of the engine H. Thus when the engine H is set in motion, a
rotary motion is imparted to the shaft Is by the pulleys H2, I and belt I7; and
the rotary motion of this shaft I is imparted by the pinion 1 and gear wheel [³
to the shaft 12, which in turn by the bevel gear wheels I¹ and I, rotates the pick
shaft E and, as the latter is connected by the gear wheels E' and E8 with the
other pick shaft E', the picks on the said shafts are rotated in unison.
The carrier F is provided with a sprocket chain F' and buckets F2 secured
thereon, the said chain passing over the sprocket wheels F5 journaled in the
front end of the frame and over the sprocket wheels F, secured on a shaft F
mounted to turn in suitable bearings at the rear or upper end of the frame D.
On this shaft F is secured a gear wheel F, connected by an intermediate gear
wheel F with a gear wheel 18 attached to the driving shaft 12, so that the
latter when rotated as previously described, imparts a rotary motion by the
gear wheels I, F and F to the shaft F³, whereby the sprocket chains F" are set
in motion, and the buckets filled by the picks E carry the material to the rear end
of the machine, to finally discharge the material into a wagon, chute or other
suitable device.
In order to bring the picks E and the front end of the carrier F to the proper
depth in the ditch to be made, it is necessary to vertically adjust the slide C; and
for this purpose I provide the latter, at its front face, with racks C in mesh with
pinions J, secured on a transversely extending shaft J, turning in suitable
bearings on the guideways B. One outer end of the shaft J is provided with a
gear wheel J in mesh with a pinion Jª secured on a shaft J' mounted to turn in
suitable bearings in one of the guideways B, and adapted to carry a crank arm J³
(Figure 2) to permit the operator to turn the sail shaft and pinions, to impart a
rotary motion to the gear wheel J2 and shaft J³, so that the pinions in mesh with
the racks C, cause the slide C to move down or up in the guideways B, according
to the direction in which the crank arm J³ is turned. If desired, the crank arm J'
may be applied directly on the outer, square end J of the shaft J¹.
In order to secure the slide C in place after it is adjusted vertically in the
guideways, provide screws K, screwing in the transverse bar B' connecting the
upper ends of the guideways B with each other.
In order to steady the frame D while the latter swings up or down, I provide a
rope or chain L winding on the shaft G2 of the hoisting device Gin an opposite
direction to the winding of the rope or chain G, see Figure 1. This rope L
extends from the shaft over a sheave L' hung on a post D' projecting at an
angle from the frame D, as is plainly shown in the drawings, and the rope L after
leaving the sheave L' extends downward aud connects with an eye or other
device attached to the carriage A. The shaft G of the hoisting device G' is

page_text: connected by means of a gear wheel G³ with a pinion Gattached to the driving
shaft G having forward and reversing pulleys G connected by belts G7 with
forward and reversing pulleys H2 on the driving shaft of the engine H. A suitable
shifting fork G serves to manipulate the belts G' so as to cause a forward or
reversing motion of the said shafts G and G².
When the machine commences to work, the frame D stands in a vertical position,
as illustrated in Figure 3, it being understood that the frame D has been fed down-
ward the desired distance by the operator turning the crank arm Js, to impart a
downward sliding motion to the slide C as previously described, and after the
adjustment has been made, the slide C is fastened in place by the screws K. The
operator now starts the engine H and connects the engine with the hoisting
device G¹ by the shifting lever Go, whereby the picks E are rotated, and a
travelling motion is imparted to the carrier, and an upward swinging motion is
given to the frame D. Thus the picks E cut into the ground, loosen the saine
and permit the loosened ground to discharge directly into the buckets of the
carrier F, the material readily passing by its own gravity into the said buckets, to
be carried off by the latter to a place of discharge at the top, rear end of the
frame D. The carriage A may be moved forward at the same time, to cause the
revoluble picks to enter the ground to the full depth of the picks, so that a large
amount of material is cut and removed during one upward swinging motion of the
frame D.
Thus it will be seen that by the arrangement described, a segmental cut is made
in the ground from a vertical to an approximately horizontal position assumed by
the frame D. After the cut is made, the hoisting device G¹ is reversed by shifting
the fork G correspondingly, so that the ropes G and L lower the frame D until the
latter assumes again a vertical position. The carriage A is then again moved
forward, and a new cut is made in the manner above described.
As illustrated in Figures 9 and 10, the machine is arranged for tunneling
purposes, and in this case I provide the frame D with two sets Ñ, N¹ of revoluble
picks and endless carriers, both sets being, however, alike in construction and
similar to the one described above, the only difference being that the shafts and
carriers extend obliquely, as plainly indicated in Figure 10. The frame D is
hinged upon a wheeled frame O, mounted to travel transversely on a carriage P
adapted to be moved forward on suitable rails P¹ which are laid in the tunnel as
the work progresses. A chute R serves to carry the material discharged by the
buckets of the two sets N, N¹ of picks and carriers, upon an endless carrier S,
extending upwardly, so that the material removed in the tunnel by the two sets of
picks and carriers, is discharged upon cars traveling on the rails P¹ and serving to
carry the material to a place outside of the tunnel.
It will be seen that the machine can be used for making ditches, canals, tunnels,
etc.; and if desired, it may be used for boring holes in the ground, and in this case
it is necessary to swing the frame back of the perpendicular when lowering the
slide C so that the picks will loosen the earth before the buckets come in contact
with it. It is necessary to keep the picks and buckets going all the time of coming
back from the horizonial to the vertical position. The buckets take up all of the
loose earth that is spilled over when the buckets are coming up so that each cut is
cleaned up before a new one is commenced.
Instead of imparting a swinging motion to the frame D by the ropes and hoisting
gear as described in reference to Figures 1, 2 and 3, gearing is employed and
provided with a gear wheel T held loosely on the front shaft 12 but attached to an
arm D on the frame D, as shown in Figures 9 and 10. A pinion T is in mesh
with the gear wheel T, and is secured on a shaft T2 journaled in the frame O and
carrying a pulley T³ connected by a belt T with a pulley T adapted to be turned
either by hand or power as desired, to impart an up and down swinging motion to
the frame D. By having two sets of revoluble picks and carriers, as described,
and moving the same transversely after a cut is made the entire width of the tunnel

page_text: is excavated, and by setting the sets of picks and carriers obliquely as described and
shown, the machinery does not come in contact with the sides of the tunnel.
It is expressly understood that by my method of excavating, the material is
undermined by the picks, and consequently the loosened material falls by its own
gravity into the buckets of the carrier. It is further understood that the frame D
can be swung above a horizontal line so that material can be removed at any
desired height.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is,
1. An excavator, provided with one or more revoluble picks on parallel shafts
mounted on a supporting frame for cutting and loosening the material, and an
endless carrier into which the material as it is loosened by the picks falls by its
own gravity to be carried off and discharged, substantially as shown and described.
2. An excavator having in combination with a swinging supporting frame, a set
of revoluble picks comprising two shafts, the said shafts being arranged in a plane
parallel to a chord of an are of the circle in which the shafts swing, and geared
together to rotate in unison, and picks secured to said shafts, substantially as shown
and described.
3. An excavator, provided with a set of revoluble picks comprising two shafts
geared together and mounted on a swinging frame to rotate in unison in opposite
directions, and picks secured to the said shafts, the picks on one shaft being
arranged alternately and at angles with the picks on the other shaft, substantially
as shown and described.
4. An excavator, comprising a vertically movable slide frame, a frame mounted
on said slide frame, to swing above and below its pivotal point, revoluble picks
mounted to turn on the said frame, and an endless carrier mounted on the said
frame under the said picks, to intercept and receive the material loosened by the
said picks, substantially as shown and described.
5. An excavator, comprising a carriage having vertical guideways, a slide held
adjustable in the said guideways, a frame hinged on the said slide, picks mounted
to turn on the said frame, and an endless carrier mounted on the said frame
underneath the said picks, to intercept and receive the material loosened by the
said picks, substantially as shown and described.
6. An excavator, comprising a carriage having vertical guideways, a slide
adjustable in said guideways, a frame mounted to swing on the slide, revoluble
picka mounted to turn on the said frame, an endless carrier mounted on the said
frame under the said picks to intercept and receive the material loosened by the
said picks, and means, substantially as described, for imparting an up and down
swinging motion to the said frame, as set forth.
7. An excavator, comprising a vertically adjustable slide frame, a frame mounted
to swing on said slide frame, revoluble under cutting picks mounted to turn on the
said frame, an endless carrier mounted on the said frame under the said picks, to
intercept and receive the material loosened by the said picks, and means,
substantially as described, for imparting a simultaneous rotary motion to the said
picks, and a travelling motion to the said carrier, as set forth.
8. An excavator, comprising a carriage having vertical guideways, a slide held
adjustable in the said guideways, a frame hinged on the said slide, revoluble picks
mounted on the said frame, an endless carrier mounted on the said frame under-
neath the said picks, to intercept and receive the material loosened by the said
picks, and means, substantially as described, for raising or lowering the said slide in
its bearings, as set forth.
9. An excavator, comprising two carriages, one of which is mounted to travel
transversely in the other, a frame hinged on the transverse moving carriage, two
sets of revoluble picks mounted on the said frame and projecting obliquely beyond

page_text: the sides of the frame, and an endless carrier for each set of revoluble picks,
substantially as shown and described.
10. An excavator, comprising two carriages, one of which is mounted to travel
transversely in the other, a frame hinged on the transverse moving carriage, two
sets of revoluble picks mounted on the said frame and projecting obliquely beyond
the sides of the frame, an endless carrier for each set of revoluble picks, and means
for imparting a simultaneous motion to the frame, picks and carriers, as set forth.
Dated this 30th day of June 1896.
A. M. & WM. CLARK,
53 Chancery Lane, London, Chartered Patent Agents.
A. M. & WM. CLARK,
53 Chancery Lane, London, Chartered Patent Agents.