AN IMPROVED MACHINE FOR EXCAVATING EARTH.
Year: 1854

page_text: LETTERS PATENT to John Taggart, of the State of Massachusetts, of the
United States of America, for the Invention of "AN IMPROVED MACHINE
FOR EXCAVATING EARTH.".
Sealed the 21st April 1854, and dated the 9th February 1854.
COMPLETE SPECIFICATION filed by the said John Taggart at the Office of
the Commissioners of Patents, with his Petition and Declaration, on the
9th February 1854, pursuant to the 9th section of the Patent Law
Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, be it known
that I, JOHN TAGGART, of the State of Massachusetts, of the United States of
America, have invented "AN IMPROVED MACHINE FOR EXCAVATING EARTH," and I
do hereby declare that the same is fully described and represented in the fol-
lowing Specification, and the accompanying Drawings, letters, figures, and
references thereof:-
Of the said Drawings Figure 1 denotes a top view of my machine; Figure 2,
a side elevation of it; Figure 3, a vertical, central, and longitudinal section
of it.
In the said Drawings A denotes the main platform upon which the operative
parts of the machine is supported; such platform being of a triangular shape,
and made to rest on two trailling wheels B, B, and a smaller guide wheel C,
fixed in the lower end of a vertical swivelling or turning shaft E.

page_text: F is a secondary platform, and it is made to rest on the primary platform
and turn horizontally on a center post, or short spindle G, that is extended
upwards from the primary platform, and has a large toothed geer H fixed
firmly and immoveably to its upper end and above the plane of the top of the
secondary platform.
The said secondary platform is made to sustain the crane I, from which the
excavating scoops are made to depend. These excavating scoops are formed of
or made like two cups a, b, respectively attached to the inferior arms of two
levers c, d, that are made to cross one another, and turn on a common fulcrum
or pin e, extending from the prongs of a forked boom K. The said forked
boom K is made to extend through a rocker tube or eye L, that is jointed to
a rocker frame N, which turns on a bolt or pin at the head of the crane. The
last-mentioned rocker frame rotates in a plane transversely of the crane, while
the rocker that is jointed to it is to be so jointed as to be capable of
moving or turning in a vertical plane, that is, perpendicular to the plane of
movement of the rocker frame N.
The object of the rocker tube and frame is to permit the forked boom K to
be swung or moved in any direction, either towards or away from the crane or
transversely of it. At the head or top of the crane there is a pulley or sheave
M, over which a rope N¹ extends from a windlass barrel O. This rope, after
passing over the pulley at the crane, is separated into two branches or ropes
f. 9, which extend downwards, and in opposite directions through the boom,
(or around sheaves h, i, arranged in the boom, as seen in Figure 4, which is a
front view of the boom and excavating scoops,) and united in one rope are
passed around sheaves k, l, arranged respectively on the superior arms of the
scoop levers.
The scoops are formed very much like the two halves of a bivalved shell, and
each has attached to it one of two branch ropes m, n, which are connected to
it, (as scen in Figure 2,) and to a rope o, which extends upwards, and is
carried around a sheave p, (applied in the upper part of the crane,) and thence
descends to and is wound around a windlass barrel s, arranged as seen in
Figure 3. From this windlass barrel a rope t descends, and has a weight u
appended to it. On the shaft of the said windlass barrel is a brake wheel u',
around which a spring brake v passes, and is attached to and worked by a
hand lever w, arranged as seen in Figures 1 & 2. One end of a rope x is
attached to an arm or strut y extending from the top of the crane; from this
strut a rope passes upwards and through the top of the excavator boom K,
and around a sheave y', placed therein; thence it descends to the secondary
piatform, as seen in the Drawings. The object of this rope is to prevent the

page_text: boom K from rising upwards when the excavating scoops are being closed;
this being done either by draft on the lower end of the rope or by winding the
rope around a suitable belaying pin affixed to some proper part of the crane.
The main driving shaft Z is worked by a steam engine, shown at A', or by
power applied to a crank C'.
On this shaft is a pinion geer D' that engages with a large spur geer E' that
is fastened to a horizontal shaft F¹, see Figure 5, which denotes a transverse
section of the machine, taken through the axis of the shaft F. The said shaft
F carries the windlass barrel o, which revolves freely upon and is so applied to
it as to be capable of being slided endwise upon it.
To this shaft and windlass barrel a common clutch G¹ is applied, and the
windlass barrel is moved on the shaft by means of a forked lever H', such
movement being either for the purpose of clutching the windlass to the shaft
or unclutching it therefrom, according to the direction in which the movement
is made.
When the windlass barrel is clutched to the shaft, and the shaft is put in
rotation, the rope of the windlass will be wound upon it, and by its action on
the scoop levers will cause the excavating scoops to approach one another and
finally close together. When they have closed together, the line by which the
boom is held downwards is slackened. As soon as this takes place, the further
movement of the windlass in winding up its rope will cause the boom and
scoops to be elevated vertically. During the time the scoops are closing the
rope o will be wound around the windlass barrel s by the descent of the weight
u, the said weight serving to keep the rope and its branch ropes drawn
taught.
As soon as the scoops have been elevated and moved over the spot where
the contents of the scoops are to be discharged, an attendant lays hold of the
brake lever of the brake wheel of the windlass s, and pressing it downwards,
brings the brake into action upon the brake wheel, so as to arrest any rotary
movement of it. This being done, he lays hold of the forked lever of the
windlass barrel o, and moves it so as to unclutch the said windlass barrel o
from the shaft on which it turns. As soon as this takes place the booni
and scoops are set free, so that they can descend by the power of gravity,
which taking place, their weight will be thrown upon the branch lines
m, n, so as to cause the scoops to open apart and discharge their load. As
soon as this takes place, and the scoops have been moved over the ground to
be excavated, the brake lever is to be elevated, so as to remove the pressure
of the brake from the brake wheel, and permit the scoops to descend to the
ground.

page_text: On the outer end of the shaft of the windlass barrel O, a small bevelled
geer a² is fixed. On a vertical shaft b, placed close to the bevilled geer a², two
other bevelled geers c², d², are fixed, one above the bevelled geer c² and the
other below it, as seen in the Drawings. This shaft 62 slides freely in vertical
directions, and is made capable of being raised or lowered by means of a
lever f, and so as to bring either one of the geers c, d, into engagement with
the
geer a³, or both of them out of engagement with the same, as circumstances
may require. There is fixed on the lower end of the shaft be a geer e, which
is made to engage with a large rotating geer H. The geer e³ is to be made
much wider than the geer H, in order that the two geers may be in engage-
ment with each other whenever either of the geers c, d is in engagement with
the geer a².
The object of the bevelled geer a, sliding shaft 62, bevelled geers c², d³,
and geer at the lower part of the shaft 62, is for the purpose of enabling
the crane to be turned around horizontally either in one direction on the
spindle G, by the action of the driving power exerted through the shaft of the
windlass O, as will readily be understood by the description herein-before
given.
My improved machine for excavating is intended to be operated by a steam
engine located on its secondary or crane platform; the boiler of such steam
engine being seen at h² in the Drawings; being the chimney of said boiler.
The mode of operation renders it very effective in excavating soil, and for
the purposes of dredging rivers or harbors, etc.
By means of its two scoops operating together in the manner above explained,
the machine may be made to dig a vertical pit or hole, and to operate to much
better advantage in many respects than the single scoop dredging machines
which have their scoops drawn through the earth to be raised.
What I claim as my Invention in the above-described machine is, the
combination of the friction brake v, the brake wheel u¹, the windlass s, the
weight u, its line t, and the line o, and branch ropes m, n, with the excavating
scoops and the framework of the machine, so as to operate substantially in
manner and for the purpose as specified.
And I claim the combination of the two scoops and their levers and closing
line with the boom K, the whole being made to operate together substantially
in manner as above set forth.
And in combination with the main supporting platform and the secondary or
turning platform of the crane, and the main driving shaft, or the windlass
barrel shaft, or shaft receiving motion from the driving shaft, I claim,
machinery applied and operated substantially as described, and so as to

page_text: cause the secondary platform and frame to be moved horizontally on the main
platform either way, as specified; such machinery consisting of the bevelled
geer a², the sliding shaft be, the geers c, d, e, & H, the same being applied
to the spindle G and the shaft of the windlass barrel O, and operated as
explained.
In testimony whereof, I have hereto set my hand and seal, this Four-
teenth day of January, in the year of our Lord One thousand eight
hundred and fifty-four.
JOHN TAGGART. (L.S.)