US 3586182 A
Description (OCR text may contain errors)
O United States Patent n113,586,182
 Inventor Friedrich Schwing  References Cited Rathausstr. I26. 468 Wanne-Eickel, UMTED STATES PATENTS Germany Rem-11746 12/1959 Pilch 214/776 211 AppLNo, 817,062 6 k 214138 Filed p 7,1969 3,166.205 1/19 5 Symman .t  Patented June 22, 1971 Primary Examiner-Gerald M. Forlenza  Priority Apr. 18, 1968, Mar. 31, 1969 Assistant Examiner-Lawrence Oresky  v A t i Att0rneyMalcolm W. Fraser (31 A3806/68 and A3 176/69 ABSTRACT: A trench hoe in which the dimension of a trapezoid control system or linkage comprising the digging bucket, the dipper arm, the front thrust piston drive, and the partial ff g g v g FOR TRENCH HOE length of the ground outrigger arm between the dipper arm a rawmg axis and the pivoting of the front thrust arm, in relation to the  US. Cl 214/138 dimensions of the ground outrigger arm, that the dipper arm in [51 1 Int. Cl .1 ROM 3/32 operation at a desired angle of slope or gradient is guided ap-  Field of Search 214/138, proximately parallel within a predetermined range of angles or 132, 776; 37/103 slope.
PATENTED JUH22 19m SHEET 2 UF 3 BUCKET MOUNTING FOR TRENCIII HOE BACKGROUND OF THE INVENTION The invention relates to a trench hoe provided with a digging bucket which is pivoted to a shaft for actuation by a forward thrust hydraulic piston. The bucket shaft may035859966 be pivoted to an outrigger arm, which is actuated by a rear thrust'piston. A third thrust piston is provided for actuating the assembly. Such mechanism must be as simple as possible to keep the cost as low as possible, but it must be controllable by the operator with a minimum of control movements.
With known trench hoes, the front piston drive, which serves for the actuation of the digging bucket, is pivoted to the shaft. With these devices, the excavator operator must actuate three thrust piston drives simultaneously, if the digging bucket is guided along a straight line and the correct digging angle is to be carried out. Therefore, the trench produced in this manner is very inaccurate.
Trench hoes are, however, already known which entirely take away from the operator this type of complicated control movements. These trench hoes adhere exactly to a given digging angle, because the digging bucket is guided forcefully on a straight line. The technical expenditure required for the purpose, however, is appreciable, because of the multiplicity of necessary control devices.
The trench hoe above described was previously solely to be driven with a loading or charging shovel, and insures, however, an almost parallel guidance of the shovel solely upon horizontal thrust at the height of the plane of position of the machine.
Summary of the Invention The problem serving as basis for the invention is to construct the trench hoe in such manner, that with a movement imparted to it, the digging bucket maintains a given digging angle. This problem is solved according to the invention, in that the digging bucket is' constructed as a ditcher and that the dimension of the trapezoid control system is so constructed of the bucket, the dipper arm, the front piston drive, and the partial length of the ground outrigger arm between the dipper arm axis and the pivoting of the front thrust piston drive in relation to the dimensions of the ground outrigger arm, that the dipper arm in operation at a desired angle of slope or gradient is guided approximately parallel within a predetermined range of angles of slope or gradients.
Thereby it is attained that upon control of the excavator operator, the front thrust piston drive need not be adjusted at all or only to a slight degree for the maintenance of the angle of intersection. It may be restricted substantially to the actuation entirely of the rear thrust piston drive and of making corrections by the third thrust piston drive.
It is first of all surprising that if the excavator operator omits these corrections, a trial line results because apparently the parallel guidance characteristics of the ditcher are so excellent that through raising of the excavator as the case may be, the correction omitted by the excavator operator will be carried out automatically.
In contrast to the trench hoes known previously, the servicing of the new excavator is also still simplified in this way, that dumping at the end of the digging movement is positively out of the question. Upon extension of the outrigger arm into its highest position, the dipper ann maintains a position at which a dumping of the bucket contents is out of the question.
With the trench hoe so far described, a trapezoid control system is formed out of the digging bucket, the dipper arm, the front thrust piston drive and the partial length of the ground outrigger arm between the dipper arm axis and the pivoting of the front thrust piston drive. This trapezoid control system requires that the pivoting of the front thrust piston drive on the ground outrigger arm and the pivoting of the dipper arm on the ground outrigger arm lie close to one another. This may lead to considerable construction problems, if the front end of the ground outrigger arm is forked in order to be able to receive the rear end of the dipper arm.
According to the invention, the rear pivoting of the front thrust piston drive is at a greater spacing from the pivoting of the dipper arm to the ground outrigger arm, in order thereby to simplify the construction problems in this area without meanwhile giving up the advantageous features of the parallel guidance of the dipper arm under a desired angle of slope or gradient.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side view of a trench hoe equipped with bucket mounting according to the invention, showing two positions of the digging bucket;
FIG. 2 is a side elevation of the trench hoe corresponding to FIG. 1, with an angle of slope or gradient of the digging bucket decreasing from the horizontal plane; and
FIG. 3 is a view similar to FIG. 2 with a horizontal digging plane lying below the ground level.
DESCRIPTION OF PREFERRED EMBODIMENTS In the figures, similar reference characters designate parts corresponding to one another.
The trench hoe has a chassis l, which is connected with the upper structure 2 through a rotary connection 3 and stands on a plane of position 4.
The digging device mounted on the excavator is first to be explained in its basic traits;
It consists of a digging implement constructed as bucket 5, which is swingable on the end of an L-shaped dipper arm 6 about an axis of rotation 7 with the aid of a front hydraulic thrust piston drive 8, which consists of a cylinder 9 and a piston rod 10. The piston rod 10 is pivoted to the apex of a triangular shift lever ll, one arm of which is pivoted to the inner end of the bucket 5 and the other arm of which is pivoted to the dipper arm 6 near the pivotal connection 7. The front part 13 of a ground outrigger arm 14 carries a shaft 15 for the pivoting of the dipper arm 6. For swinging the dipper arm 6 about the axis is a rear thrust piston drive 16, whose piston rod I7 is pivoted at 18 to the rearward end of the dipper arm 6, while a cylinder 19 is pivoted at 20 to the ground outrigger arm 14.
The rearward part 21 of the ground outrigger arm 14 is pivoted at 22 to the upper structure of the trench hoe. The ground outrigger arm 14 is actuated by a third thrust piston drive 23.
The digging bucket 5, the dipper arm 6, the front thrust piston drive 8 and the partial length of the ground outrigger arm I4 between the dipper arm axis I5 and the pivot 12 of the front thrust piston drive 8 form a trapezoid control system' (Trapezlenkersystem). This trapezoid control system is laid out in relation to the dimensions of the ground outrigger arm 14 so that the dipper arm 6 is guided approximately parallel at desired angles of slope or gradients, three of which are shown in FIGS. 1 to 3, which all lie within a predetermined range of angles of slope or gradient. Insofar, the showings in the figures are indicated accurately enough and the dotted line showings indicate that insignificant deviations from the predetermined angles of starting movement are adjusted at the end of the digging movement. These are, however, for practical conditions negligibly small and could furthermore be equalized by means of a corresponding control movement.
In detail, FIG. 1 shows the insertion of the new device with a slantingly rising inclination with'an angle of slope or gradient of 1:1.5, while FIG. 2 illustrates the same, however, decreasing angle of slope or gradient; FIG. 3 shows the device on a surface lying horizontally.
Deviating from the embodiment shown by way of example, the rear thrust piston drive 16 may also be so disposed that it does not engage on the projecting end of a dipper arm but at a desired point between the axis 15 and the axis 7. The articulation of the front thrust piston drive 8 has solely as prerequisite that it is conducted outside of the axis of rotation 15, so that the axis 12 may be disposed at a desired point between the axis 15 and the axis 22 of the ground outrigger arm. I
If the trench hoe in accordance with the invention is laid out so that in the large range of angles of slope or gradients necessary for trenches a sufficient parallel guidance of the digging bucket is attained, then also other digging implements which do not have to be guided parallel in so great an angle range, may be utilized effectively, for example, loading shovel and highdigger or shovel.
In all figures it is shown in two phases, that the digging bucket upon exploration is guided approximately parallel under a designated and desired angle of slope or gradient within a predetermined range of angles of slope or gradients. The parallel guidance is attained by means of a corresponding dimensioning of the control system of the digging bucket 5, dipper arm 6, front thrust piston drive 8 and the partial length of the ground outrigger arm or jib 14 between dipper arm axis 15 and pivoting of the front thrust piston drive, in which the described control system 30 is interpolated, in relation to the dimensions of the ground outrigger arm 14.
In practice it has been found that the trench hoe operator does not need to readjust except in a very small degree for the maintenance of the particular digging angle. He may thereupon limit himself essentially to full actuation of the rear thrust piston drive 16 and with correcting at the time the third thrust piston drive 23. if he omits these corrections, the straight line of digging occurs by itself, because apparently the guidance characteristics of the bucket 5 guided in parallel are so excellent that the bucket rises in case the operator omits the corrections in proper time and thereby insures automatically the maintenance of the digging angle.
' Whatlclaim is:
l. A trench hoe comprising a digging bucket, a triangular shift lever having one arm pivoted to the inner end of said bucket, a front hydraulic thrust piston drive having a piston rod pivoted to the apex of said shift lever, a dipper arm at one side of said shift lever and pivoted at its outer end to said bucket inner end and in spaced relation to the pivotal connection of said shift lever and said bucket, a pivotal connection between the other arm of said shift lever and said dipper arm in close spaced relation to said pivotal connection between said dipper arm and bucket, a ground outrigger arm, means providing a pivotal connection between the outer end of said outrigger arm and the inner end of said front thrust piston drive, means providing a pivotal connection between said outrigger arm and said dipper arm in close spaced relationship to the pivotal connection means between said thrust piston drive and said outrigger arm and at the other side of said triangular shift lever, and L-shaped inner end portion on said dipper arm, a rear hydraulic thrust piston drive connected to the end of said L-shaped inner end portion of said dipper arm and disposed above said ground outrigger arm, the arrangement being such that a trapezoid control linkage for said digging bucket is provided consisting of said bucket, said dipper arm, said front thrust piston drive, and the partial length of said ground outrigger arm between said dipper arm axis and the adjacent pivotal connection of said front thrust piston drive, and said control linkage being so dimensioned in relation to the dimensions of said outrigger arm that said digging bucket is guided in operation approximately parallel to its starting position by tilting it about its pivotal mounting during digging action under a desired angle of slope or gradient within a predetermined range of angles of slope or gradient.