Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates generally to powered
excavating apparatus and more particularly to a combined
excavating and conveying apparatus arranged to dig and
convey large quantities of material such as ore in a mining
operation.
In many mining operations, digging or breakout
forces in the neighborhood of 200,000 pounds are required/
and at the same time, for practical utilization, the exca-
vated material must be removed at rates approaching 100 tons
per hour. With existent equipment these two practical
requirements are not achieved. For example, mechanical
devices such as backhoes and front end loaders could pos-
sibly deliver the requisite forces but have not the capacity
to remove the material in such large quantities. On the
othex hand, certain boom-mounted rotary heads can remove the
material at adequate rates but are not only incapable of
delivexing the xequisite forces but also establish force
components which tend to move the entixe machi~e sideways so
as to render its operation impractical.
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Both problems are aggravated when one wi~hes to perform the
excavating and conveying operation in a mining tunnel whose lateral dimensions
conventionally are no more than six feet high and five feet wide, since the
mentioned breakout or digging forces are sufficient to lift or transversely
displace the mobile carrier for the equipment. The problems could be
alleviated if it were possible, as in some surface applications, to mount
a counterbalance weight behind, and in line with, the digging bcom or arm,
so as to be capable of swinging therewith. In the confined space of tunnel
digging or mining, which the present device wishes to be capable of, such
a solution is out of the question.
~ he present invention seeks to overcome the aforementioned problems
but providing a continuous excavating apparatus camprising a longitudinally
elongated, low, narro~ frame including a first side-counterweight and a
second side-counterweight transversely spaced therefrom, each side-counterweight
being formed of a heavy metal elongated plate means of substantially greater
length than its width or height; a mobile ground engaging means for said
frame; a gimbal mounted on the forward end of the frame for pivotal motion
about a vertical axis; a boom mounted on the gimbal for movement about a
horizontal axis; the boom including an endless excavating bucket line for
digging material at the movable free end of the boom to cause, while digging,
a force tending to pivot the frame about a leading end of the ground
engaging means; means connecting the boom to the frame at a level substantially
the same as the ground engaging means for adjusting the bcom and for resisting
the force; the frame having an effective center of gravity and sufficient
dead weight to provide a greater counter force around the leading end of the
ground engaging means than the pivoting force to maintain the bucket line in
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an excava-ting position and each heavy metal plate n~ans having a center
of gravity and sufficient dead ~eight to provide a counter force to forces
tending to rotate -the frame about i-ts longitudinal axis when performing
an off center digging operation.
In a preferred e ~ iment the mobile ground engaging means is a
driven pair of endless tracks, located beneath the frame and substantially
thin the lateral extent thereof and extending forwardly of the forward
end of the frame, the frame overhanging the rear end of the endless tracks.
Preferably a conveyor means is provided, extending upwardly and
rearwardly from a point adjacent ~he front end to-a point adjacent the rear
of the frame and being located between the side-counterweights for receiving
material from the bucket line.
The continuous excavating apparatus has a minim~m profile or contour
so that it can be utilized in a confined area such as a mining tunnel, and
yet is capable of providing the requisite excavating forces and of conveying
the excavated material at a relatively high rate of speed, approaching 100
tons per hour.
The lateral dimensions of the heavy elongated frame are limited
so that it can pass through a tunnel of dimensions no more than six feet in
height and five feet in width, yet the frame is of sufficient weight
that experien oe d foroes during the excavating and conveying operations can be
accomm~dated.
Preferably the plate means each includes a pair of heavy plates
each pair being welded or otherwise joined at their edges and prDviding a
total mass approachiny fifty tons which together with the equipment mounted
on the frame provides a siynificant counterbalance to the digging forces.
Accordiny to a preferred feature of the invention the bucket line
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includes a plurality of excavating buckets, adjacent buckets being pivotally
connected by a common hinge pin, and a pair of spaced sprockets rotatively
supported at each end of the boom and engaging opposite ends of the common
pins, each of the pins includes enlarged ends arranged for engagement with
the sprockets to cause the enlarged ends tD roll in the sprockets and the
central portion of the pin to rotate during operation. m e rDtation of the
center portion of the pin in contact with the hinges evenly distributes pin
wear.
m e present invention, as briefly summarized herein above, will be
m4re fully understood by references to the following detailed description of
an exemplary structure
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shown in the accompanying drawings wherein:
Figure 1 is a side elevational view of a con-
tinuous excavating apparatus embodying the present in-
vention,
Figure 2 is a top plan view thereof,
Figure 3 is a transverse sectional view taken
along line 3-3 of Figure 1 illustrating the gimbal mounting
of the excavating boom and details of the bucket structure,
Figure 4 is a fragmentary longitudinal sectional
view through the excavating boom illustrating additional
details of its construction, and
Figure S is a transverse sectional view taken
along line 5-5 of Figure 4 illustrating additional struc-
tural details of the excavating boom.
With initial reference to Figures 1 and 2, the
continuous excavating apparatus embodying the present
invention includes a main frame 10 having most of its weight
in substantially vertical side walls 12, 14, each formed
preferably by a pair of continguous plates which are welded
or o~herwise secured at their front, rear, and the top and
bottom edges thereof. The frame plates are joined by
transverse braces 16, 18 so that the overall configuration
of the frame is in ~he form of a hollow channel or box-like
configuration, within which certain additional elements of
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the apparatus can be housed, as will be explained in detail
hereinafter.
To provide mobility of the heavy elongated main
frame 10, a pair of conventional endless tracks 20 are
- 5 mounted therebelow in a conventional fashion but at a
position so that the endless tracks project at the forward
end of the main frame 10 therebeyond but are recessed from
the rearward end of the frame for a purpose which will
become apparent hereinafter. As can be seen, particularly
by reference to Figure 2, the endless tracks are confined
within the lateral contours of the frame so that its overall
width is less than five feet and the endless tracks have a
height such that, when added to the height of -the side
plates, provides an overall vertical dimension of less than
six feet. Thus the entire elongated frame and the moblle
carriers therefor can pass readily through a tunnel having
lateral dimensions no more than six feet in height and five
feet in width.
To power the endless tracks and certain additional
equipment to be described hereinafter, an electric motor 22
of appropriate power is mounted at the rearward end of main
frame 10 on one of the mentioned transverse braces, the
precise drive arranyement to the endless tracks being
conventional and thus not described in further detail.
Adjacent the forward extremity of the elongated
main frame 10 the mentioned upper and lower transverse
braces 16, are joined riyidly to the side walls 12, 1~ to
support gimbal pins 24, 26 that rotatably carry an open
rectangular gimbal frame which, as best shown in Figure 3,
can pivot about a generally upright axis and is, in turn,
arranged to pivotally support on a transverse shaft 30 the
parall~l side plates 32, 34 of an excavating boom, generally
indicated at 36, ena~ling its pivotal adjustment about a
transverse axis so that the excavating boom can be pivoted
both vertically and transversely an amount sufficient so
that its extremity can move beyond the lateral and upright
contour of the described supporting frame, as indicated by
phantom lines in ~igures 1 and 2, thus enabling a tunnel to
be excavated which will subsequently allow the passage of
the entire frame therethrough.
The side plates 32, 34 of the excavating boom 36
are held in laterally spaced relation by simple rigid metal
braces 38 and the outer surfaces thereof mount balls 40, 42
for universal connection to ball sockets 44, 46 at the
forward ends of douhle-acting hydraulic rams 48, 50 whose
opposite extremities are universally joined to a forward
extension 10a of the main frame 10 by similar ball and
socket joints 52, 54 to allow the excavating boom to be
adjusted vertically or horizontally through actuation of the
hydraulic rams 48, 50 by a hydraulic pump 56 that is driven
by the previously descrlbed electric motor 22. One valve
(not shown) is associated in a conventional fashion with
each hydraulic ram and is arranged to supply hydraulic
pressure to one or the other end of its associated ram so
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that, as will be apparent, if both valves are open in one
direction, both hydraulic rams will extend or retract to
raise or lower the excavating boom, whereas on the other
hand, if one valve is open in one direction while the other
is open in the opposite direction, a lateral motion of the
boom will occur; for example, to the phantom-line dispo-
sition shown in Figure 2.
Between opposite ends of the described boom side
plates 32, 34 laterally-spaced sprockets 58, 60 are mounted
at the extremities of tubes 62, 64 which are keyed to
mounting shafts, one of which is the previously described
shaft 30 (see Figure 3) and the other of which is an idler
shaft 66 (see Figure 4) rotatabl~ supported between the side
plates 32 9 34 at the remote free end of the excavating boom
36. Each pair of sprockets engages the enlarged opposite
ends of a hinge pin 68 which is arranged in bridging re-
lationship between the laterally-spaced sprockets to ro-
tatably extend through a piano-hing connection in the form
of interdigitated hinges 70, 72 at the front and rear of
adjacent excavating buckets 74, which provide the material
excavating elements of the unit. When it is remembered that
considerable forces are encountered during the excavating
operation, the enlarged ends of the pin 68 will rotate to
provide only rolling friction with the engaged sprocket,
thus to reduce sliding friction and extend the useful life
of the elements to a considerable extent. Furthermore, it
will be seen that each hinge pin 68 common to the foremost
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extremity of one bucket and the rearmost extremity of the
adjacent bucket will xotate in the hinges 70, 72, thus to
distribute wear and maintain the roundness of the hinge pin
and the hinges.
In consideration of the extreme wear experiences
by the digging ends of the excavating buckets, replaceable
hard teeth 76 are utilized, and, as best shown in Figure 5,
each tooth includes a tongue and groove connection 78
between it and its supporting element, which in turn faci-
litates replacement thereof after continued wear over an
extended period.
The line of buckets mounted on the sprockets is
arranged for counterclockwise motion, as shown in Figure 1,
when driven by a pair of hydraulic motors 80, 82 which are
connected to opposite ends of the sprocket-mounting shaft 30
at the inner end of the bucket line by suitable gear re-
duction units 84, 86/ such hydraulic motors each being
capable of delivering as much as 150 horsepower when ener-
gized by the hydraulic pump 56 driven by the previously
described electric motor 22.
Utilization of the described hydraulic actuating
mechanism enables a ready variation in the requisite power
dependent upon the resistance of the material beiny engaged
by the line of excavating buckets. When the buckets engage
the material, as can be readily visualized by reference to
Figure l r they will be moving in sequence in an upward
direction, tending to rotate or pivot the entire machine
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about a transverse pivot formed at the forward end of -the
endless trac~s. Since this pivot point is forwardly of most
of the weight of the heavy frame and the elements mounted
thereon, considerable forces may be generated without moving
the frame about this transverse axis, thus to assur~ the
requisite application of force during the excavating opera-
tion. Furthermore, if the excavating boom 36 is operating
at a lateral angle such as indicated in phantom lines in
Figure 2, the reactive force componen~s tending to rotate
the main frame 10 about its longitudinal axis will be
counterbalanced by the weight of the opposite side wall.
Material excavated and carried by the excavating
buckets will be dumped therefrom as they pass in succession
over the rear sprocket 58 onto a suitable endless conveyor
88 which lies thereunder and is mounted for conveyance of
material deposited thereon beyond the rear end of the frame
at an upper elevation so that the material conveyed on the
belt can be dumped into a suitable truck or other receptacle
(not shown) for removal and subsequent processing~ The
conveyor 88 is supported between the frame plates and is
powered by suitable connection to the motor 22.
Obviously, many variations and/or alterations in
this structure as specifically described can be made without
departing from the spirit of the invention, and the fore-
going description of one embodiment is to be considered aspureIy e~emplary and not in a limiting sense, and the actual
scope o~ the invention is to be indicated only by reference
to the appended claims.
