Improvements in Excavating Machines.
Year: 1892

page_text: Date of Application, 18th Mar., 1892-Accepted. 30th Apr., 1892
Improvements in Excavating Machines.
We, FRIEDRICH WILHELM VOLLHERING of Lindenplatz 1 Lubeck Germany
Mechanical Engineer and CARL BERNHARDT, of Huxterdamm 14 Lübeck,
Germany Mechanical Engineer do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :-
For all excavating work by means of excavating machines it is desirable to
arrange the rails on which the machine runs in such manner that they only have to
be shifted laterally after the longest possible intervals of time, as such shifting of
the rails causes considerable expense.
In order to satisfy this requirement it is necessary to excavate the earth at each
operation to the greatest possible width and depth, and to maintain a definite profile
within certain limits.
In those cases where the excavated earth has to serve for forming embankments
or for filling in hollows, the further desideratum arises of being able to excavate
the upper stratum of earth to a certain depth separate from the lower strata.
The above objects cannot be carried out by means of the usual construction of
excavating machines, as the rigid bucket frame employed in swinging round its
fixed centre describes a circular are the extent of which depends upon the length of
the bucket frame and the height of the pivot centre above the level of the work.
The profile can also not be determined at will, as for every position of the bucket
frame it is determined by the curve of the bucket chain, and if the excavation is to
be effected to the depth permitted by the bucket frame it is unavoidable to excavate
the soil simultaneously from all the different strata, and consequently a mixing
of such strata both in the excavating and in the emptying of the buckets is
effected.
up
In order to obviate these defects, a parallel shifting of the bucket frame
both on the machine itself, as also on the level of the working profile, has been
employed; also divided frames have been proposed. These constructions have
however not fulfilled the requirements in a satisfactory manner.
The present invention relates to a construction which will effectually satisfy
the said conditions and which consists mainly in constructing the bucket frame
in three parts and in combining these parts by hinge-joints and so guiding
them that they can form any desired angle with each other, within certain
limits.
We will describe the construction for this purpose with reference to the
accompanying drawing, which shews a side elevation of the excavating machine.
The bucket frames consist of the parts A_C, C D, and D B; the middle
part C D is connected to the parts AC and D B by means of hinge-joints.
The part AC carries the rods AE and C E, part D B carries the rods D F,
equal to CE, and B F, and these rods are so connected together that A CE
and DBF each form a rigid triangle. The points E and F are connected by
a pivotted rod E F of a length equal to C D. By this means an articulated
parallelogram is formed between the triangles ACE and DBF which allows
of the turning of the part C D to the extent of 180° relatively to A C.
In order to enable the angle F D B and consequently also the angle CD B
to be altered for different positions of CD, it is only necessary to vary the
length of the stay FB, which may be readily practically done if the stay F B
be made of two parts which are connected by a screwed sleeve screwing
on to right and left handed screw threads on the meeting ends of the two parts,

page_text: If now the triangle FBD be raised or lowered by means of the chain m,
the angles ACD and CDB must change. To the chain m is also connected
at Ka chainn, which carries the part of the frame A. C. Consequently
the part AC will also be raised or lowered with the parts BD and CD,
and thus a further optional alteration of the angles ACD and CDB can be
effected, which will depend upon the relative positions of the chains m and a
and upon the length of the chain n between the point of connection K and the
point of its connection to the frame part A C.
From the above description it will be seen that it is easily possible by means
of such a construction of bucket frame A. CDB to produce any desired profile
within certain limits, and to remove the upper strata to a certain depth separately
from the lower strata. In consequence of its form, the bucket frame offers the
further very essential advantage of enabling, with one and the same position of
the excavating machine, to excavate to such a width and depth as it would be
impossible to effect with the same total length ACDB of bucket frame when
this is either rigid, or divided into two parts in the known manner.
On the drawing, the position of the articulated bucket frame is shewn in full
lines for the beginning of the excavating operation, and in dotted lines for the
completion of the work.
The upper width of the excavated body of earth is equal to the length of
the parts CD + DB; the lower width is equal to D B. The depth is equal
to the length C D multiplied with the sine of the angle of the camber.
For the ordinary lengths of bucket frames and angles of camber this will give
a width of about 13 feet with a depth of at least 13 feet.
For producing a straight profile it is of course necessary to guide the working
buckets in a line close against the frames. This may be effected in various known
ways whereby the chain of the buckets is made to travel over or between fixed
guides or rollers on the frames, the essential condition being that the bucket chain
shall be maintained perfectly taut on the working side; this condition is however
automatically fulfilled by the fact that the non-working length of the bucket chain
between the drums A. and B hangs perfectly free for every position of the bucket
frames.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
In excavating machines a bucket frame consisting of three parts such as A. C,
C D, and D B, connected to each other by articulated joints in such manner as to
be capable of assuming varying angular positions relatively to each other, within
the limits prescribed by the general construction and arrangement of the machine,
substantially as described.
Dated this 18th day of March 1892.