EP0158792B1 - Power shovel - Google Patents

Description

The invention relates to a backhoe excavator according to the preamble of claim 1. The backhoe excavator according to the invention is accordingly a single-bucket excavator, the digging vessel of which is preferably designed as a backhoe bucket that can be exchanged for another backhoe bucket. The excavator according to the invention can also be designed as a universal excavator, in order to select other work tools, e.g. B. to be equipped with a ram or similar device. However, the invention is preferably implemented on an exact excavator which has a straight guide of its bucket in the digging plane; Therefore, the invention is described below with reference to such an excavator.

In the case of diggers, the dipper stick is usually located at the top of the boom, which is often subdivided again, the parts being connected to one another via operating joints with articulated axes running transversely to the vertical pivoting plane of the boom, and actuated by double-acting working cylinders, the drive of which is generally hydraulic. Here, the digging tool is connected on the one hand with an operating joint to the tip of the dipper stick and has its own working cylinder, which at the

Exact excavators is connected to the boom. The pivoting movement of a bucket serving as a digging tool around the axis of the operating joint located at the end of the dipper arm serves to fill and empty the bucket and also works to adjust the cutting angle of the bucket blade or the attached fangs.

The kinematics of a shovel excavator of this kind mean that the plane of the bucket or the bucket cutting edge, which runs transversely to the boom, runs parallel to the standing plane of the excavator, provided that no correction option is installed. Although it is fundamentally possible to set the crawler or wheel chassis of the excavator so that it can be pivoted relative to the uppercarriage, or to install a correction joint in the boom in order to be able to adjust the cutting plane of the excavator independently of the level of the undercarriage, the installation of a correction joint has been made with in the articulated axis of the boom between the bucket and the dipper arm was found to be optimal. The drive of the joint is divided between the two working cylinders, which are arranged on each side of the pivot pin. This arrangement of the working cylinders, which is also common in other operating joints, enables the swiveling forces to be divided between the two working cylinders, which are therefore comparatively smaller, and also has the advantage of a lower bearing load in the operating joint. The invention relates in particular to the operating joint which directly adjoins the bucket and thus preferably to the described correction joint for changing the grazing level compared to the standing level of the excavator undercarriage, which is preferably provided on the exact excavators described.

The excavator performance can be optimized by installing different digging vessels. For loose, light soils, a large-volume spoon can give the best results, while in the rocky bottom a smaller but more resistant spoon is required. Because of the good guiding properties, the exact excavators are particularly suitable for trenches. It is advisable to use a spoon, the profile of which corresponds to the trench profile. If you use the excavator for leveling, especially wide and mostly flat buckets are cheap. Even if such an excavator is not equipped with other work tools, the work tools have to be changed more often simply because of the different buckets. Then the optimization of the performance of the excavator depends on the timely change of the working tool and thus on the fact that the change can be carried out quickly and without any special effort by the excavator operator.

If you set up components of the excavator mechanics for this purpose by z. B. the bolt of the operating joint is divided and can be actuated hydraulically for releasing or for detecting the joint bushings, this results in an additional hydraulic drive which is difficult to include in the hydraulic supply and control of the excavator. In addition, the operating joint is not insignificantly complicated and the changing of the working tools for the excavator operator is difficult. If, on the other hand, you plan to install a mechanical coupling for changing the working tool between the bucket and the operating joint, the parts of which can be brought together or released from one another by pivoting the excavator boom, then a hydraulic coupling lock must be integrated into the excavator's hydraulics when the excavator operator changes the Make work tools alone. This creates practically the same difficulties as an additional hydraulic drive. The coupling mechanism also requires that each work tool is equipped with a coupling half, which is relatively more complex than the division of the hinge pin.

The invention is based on the exact excavator forming its preferred field of application (DE-A-28 51 942), because in this backhoe excavator the operating joint adjoining the bucket represents a correction joint in the sense explained above, which is actuated by two working cylinders. If the work tool is to be changed, the operating joint must be dismantled in order to clear the dipper stick for the change after loosening the piston rods of the working cylinder from the brackets of the spoon. Equally complex is the assembly of the spoon or another working tool that is to be exchanged for the dismantled spoon.

The use of known mechanics to simplify the changing of the work tools of such an excavator already fails because they change the height of the operating joint above the digging tool so much that the straight guidance of the bucket is lost, which is achieved in the precision excavators by coordinating various handlebar parallelograms in the Parts of the boom and the working cylinder articulated to a pivoting lever of the bucket are included. In addition, the other disadvantages of these mechanisms described above would also be particularly important for an exact excavator.

The invention is therefore based on the object to enable a change of the work tool on a backhoe and thereby the necessary mechanics and their drives simple and so that they do not interfere with the straight line of an exact excavator of the type known as known and with other backhoe maintenance enable the hydraulic drives without a significant change in the hydraulic system with only slightly changed fastening means for the working tool, with only a few low-quality parts remaining on the replaced working tool.

According to the invention, this object is achieved with the features of claim 1. Appropriate embodiments of the invention are the subject of its dependent claims.

According to the invention, those used to drive the operating joint, i. H. used for the correction of the spoon required two working cylinders for the actuation of a mechanism which remains constantly on the dipper stick tip and includes the entire operating joint; by designing this mechanism according to the invention in the manner of pliers, it can grip the connections which are necessary anyway for the connection of the operating joint to the bucket or another work tool, which remain as the only, but particularly simple, components on the work tool; the locking is then only for the pliers legs i.e. Legs of the pliers-like mechanics are required for the time that the work tool in question is used on the excavator.

The invention has the advantage that it practically does not change the height of the articulated joint of the working tool due to the integration of the pliers joint in the operating joint, and therefore the straight guidance of the bucket does not degenerate prematurely or is completely eliminated in the case of the exact excavators. Since, according to the invention, the working cylinders are used to operate the tongs, one does not need to change the hydraulic control of the excavator, nor the hydraulic system for supplying the various working cylinders, and nevertheless achieves that the excavator operator can operate the tongs from the excavator and carry out the change of work tools . Since the pliers can also be kept closed with at least one working cylinder of the operating joint, the locking can be realized mechanically without disadvantage and can therefore u. a. consist of a simple bolt arrangement.

With the features of claim 2, the excavator operator can facilitate the alignment of the pliers and their actuation, because the locking of the operating joint with a working cylinder holds the associated pliers leg and the gripping movement is carried out only with the other pliers leg.

With the features of claim 3 results in a particularly flat overall arrangement, in which the height of the closed pliers legs is reduced to the thickness of the mounting plate, which is irrelevant for the straight guidance of an exact excavator. In addition, the connections remaining on the work equipment in question are attached to simple projections, e.g. B. reduced to bolts with plate-shaped heads.

With the features of claim 4, the hinge of the mounting plate can be combined with the operating joint in a particularly simple manner, the implementation of the features of claim 5 resulting in a favorable distribution of the forces onto the bushing of the operating joint.

If the excavator operator kinks the boom and the dipperstick in such a way that he has the work tool directly in view, he can usually easily, i. H. trace the movable pliers leg into the connections of the work equipment to be changed without special aids. However, this is not always possible in practice. Often the working tool is located at a greater distance from the excavator cabin and must be reached by stretching the boom.

With the features of claim 6, the assembly of the work tool to be replaced is made considerably easier because the excavator operator can use the guide bar as a guide for reaching the starting position of the pliers when pivoting the superstructure in preparation for gripping, which are achieved for the faultless engagement of the movable pliers leg got to.

• Fig. 1 in perspektivischer Darstellung die Erfindung anhand ihrer Anwendung an einen Exaktbagger,
• Fig. 2 in abgebrochener Darstellung das vordere Ende des Exaktbaggers nach Fig. 1,
• Fig. 3 eine Montageplatte gemäß der Erfindung in Stirnansicht,
• Fig. 4 eine Draufsicht auf den Gegenstand der Fig. 3,
• Fig. 5 den Gegenstand der Fig. 3 in Stirnansicht und
• Fig. 5a einen Schnitt längs der Linie V-V der Fig. 4,
• Fig. 6 schematisch die Arbeitszylinder und deren Schaltung bzw. Steuerung,
• Fig. 7 in perspektivischer Darstellung eine erste Phase beim Montieren eines Tieflöffels,
• Fig. 8 in ebenfalls perspektivischer Darstellung eine weitere Phase der Montage,
• Fig. 9 die geschlossene Zange, mit der die Montage des Tieflöffels durchgeführt wird und
• Fig. 10 den fertig montierten Tieflöffel nach Abschluß des Wechsels.

The details, further features and other advantages of the invention will become apparent from the following description of the Subject of the invention with reference to the figures in the drawing; show it

• 1 is a perspective view of the invention based on its application to an exact excavator,
• 2 is a broken view of the front end of the exact excavator of FIG. 1,
• 3 is a front view of a mounting plate according to the invention,
• 4 is a plan view of the subject of FIG. 3,
• Fig. 5 shows the subject of Fig. 3 in front view
• 5a shows a section along the line VV of FIG. 4,
• 6 schematically shows the working cylinders and their switching or control,
• 7 is a perspective view of a first phase when mounting a bucket,
• 8 is a perspective view of another phase of assembly,
• Fig. 9, the closed pliers with which the assembly of the bucket is carried out and
• Fig. 10 shows the fully assembled bucket after completing the change.

The undercarriage (1) of the backhoe (2) rests on two caterpillars (3 and 4). The superstructure (5), which can be swiveled around a kingpin on the undercarriage (1), carries the usual superstructures, including a driver's cab (6), which enables observation of the working tool (7) and from which the excavator is controlled. The digging tool of the working equipment (7) consisting of a backhoe (8) i.e. of the working tool is connected via an operating joint (9) to an upper part (10), which is shown in more detail in FIG. 2. The upper part (10) sits on an operating joint (11) which is arranged at the tip of the dipper stick (12). A pivot lever (13) is articulated via a link (13 ') to the upper part (10) and articulated via a link (14) to the piston rod of a working cylinder (15), which in turn is connected to the tip (16) of the boom (17). is attached. The handlebar (14) is supported by a double rocker arm (18) on the dipper stick (12).

The boom in turn is divided into a rocker arm (19) articulated on the superstructure (5) and a boom end piece (20). It is operated by a double-cylinder sliding piston gear, which is generally designated (22). The dipper stick is pivoted with a working cylinder (21).

The upper part (10) serves as shown in FIG. 2 for the displacement of the two working cylinders (23, 24), which together form the drive of the operating joint (9) between the bucket (8) forming the working equipment (7) and the Dipper stick is arranged. The operating joint (9) consists of the joint pin (25) mounted in the upper part (10) and the joint bushings, which are generally designated by (28) and are explained in more detail below. The hinge bushings are arranged on a mounting plate (27) which in turn is connected to the upper flat section of the bottom (28) of the bucket (8).

The details of the mounting plate can be seen from the representation of FIGS. 3 to 5. According to Fig. 4, the mounting plate is mirror-symmetrically divided on two plate halves or pliers legs (29, 30) by a hinge. The pliers legs have on their side facing the operating joint (9) or the dipper stick (31 or 32) the connection brackets (37, 38) consisting of two parallel fork legs (33, 34) or (35, 36) (Fig. 6) which connect the mounting plate (27) with the piston rods (39, 40) of the pistons (41, 42) in the working cylinders (23, 24). On the sides (31, 32) of the pliers legs (29, 30) facing the operating joint (9) there are also the parts of one half (43, 44) of the joint bushes (26). Both joint halves are identical. They consist of a console divided into two fork sinks (45, 46) which are attached to the top (31) of the pliers leg (29) and a further bracket (47) which is arranged on the top (32) of the pliers leg (30) is. The corresponding parts of the half (44) are denoted by the same reference numerals, which, however, have index marks to distinguish them. There are aligned recesses in the brackets (45 to 47) and (45 'to 47'), through which the pin (25) of the operating joint (9) can be inserted. This pin then simultaneously forms the hinge pin of a hinge about which the tong legs (29 and 30) can be pivoted. The geometric axis of the operating joint (9) therefore coincides with the axis of the pliers hinge.

The inner hinge edges (49, 50) of the pliers legs (29, 30) are provided with semicircular recesses (51 to 54). Two opposite recesses (51, 52) and (53, 54) each act with an anchoring means protruding vertically upwards from the top (55) of the spoon bottom (28) in the form of bolts (56, 57) or the one in plan rectangular plates (58, 59) together, which form the bolt heads. The bottom of the bolt heads is, as shown at (60) in Fig. 5a, convexly curved to enable the mirror-free detection of the connections formed by the bolts (56 to 59) with the pliers legs (29, 30).

As can be seen in particular from FIG. 7, a guide bar (74) is arranged on the end face (61) of the bucket (8) facing the excavator operator in the cabin (6). Their function is explained in connection with the mode of action of the pliers legs (29, 30).

As can be seen from the illustration in FIG. 6, a 2/2-way valve (63) is installed in the feed line of the working cylinder (24) and can be actuated with a manual switch (64). The feed line (62) as well as the feed line (65) controlled for the working cylinder (24) with a 2/3-way valve (66). This valve is located between the oil supply pump (67) and the reservoir (68), which is switched to circulation in the position of the directional control valve (66) shown, so that the two working cylinders (23, 24) are blocked. By adjusting the directional valve (66), the cylinders are acted on alternately, provided the directional valve (63) is in the position shown. In this way, the digging level can be corrected compared to the level of the excavator. If the directional valve (63) is changed over, the working cylinder (24) is blocked. This is usually done in an approximately horizontal position of the mounting plate (27) as shown in Fig. 6. In this position, only the piston (41) of the working cylinder (23) can be controlled with the directional control valve (66). This movement is used to open and close the pliers leg (29).

In the operating position, which is shown in Fig. 6, the unintentional opening of the pliers legs (29, 30) is excluded by a lock. According to the exemplary embodiment shown, screws are used for this purpose, which are inserted into recesses (69, 70) of the mounting plate (27) and penetrate the bottom (28) of the spoon.

As can be seen, the pliers legs (29, 30) are mirror-symmetrical to the hinge axis and the socket halves (43, 44) as well as the console parts (33 to 36) and the recesses (69 and 70) are mirror-symmetrical to the transverse axis (71) of the mounting plate (27 ) arranged.

The assembly of work equipment is explained below using the example of work equipment (7). For this it is assumed that the work equipment attached to the dipper stick (12) or the upper part (10) has already been removed. The backhoe (8) lies on the level and is oriented so that its bottom (28) is at the top.

First, the directional control valve (63) is switched over, so that the working cylinder (24) is blocked, as a result of which the tong leg (30) is fixed. The excavator operator now pivots the dipper stick and thus the upper part (10) from the cab (6) from the left to the right as shown in FIG. 7, the piston rod (39) being inserted into the working cylinder (23) and accordingly the pliers leg ( 29) is folded up. The pliers legs (29, 30) thus opened are thus prepared for the pliers legs to be engaged in the connections. 7, the excavator operator orients himself on the guide bar (74), which interacts with the front edge of the tong leg (30) and indicates to the excavator operator when the semicircular recesses (52 and 54) under the Head plates (58, 59) of the bolts (56, 57) are engaged. This position has already been reached in the illustration in FIG. 8. The pliers leg (30) lies on the top (55) of the bottom (28).

The piston (41) is extended further by actuating the directional control valve (66), so that the piston rod (39) pivots the tong leg (29) clockwise around the hinge pin (25) of the operating joint (9), which also forms the hinge axis. As a result, the semicircular cutouts (51, 53) of the pliers leg (29) are finally engaged in the connections, just like the semicircular cutouts (52, 54) of the pliers leg (30).

This state is reached in the illustration in FIG. 9. The tong leg (29) in turn lies on the top (55) of the spoon bottom (28). The excavator operator can block the further extension movement of the piston rod (39) by actuating the directional valve (66) and leave the cabin. He then turns the screw (73) through the recess (69) of the tong leg (29) into a threaded bore (69a, 70a) in the bottom (28) of the bucket (8), which together with a screw (73) passes through the recess (70) of the tong leg (30) in a threaded bore (69a, 70a) of the bottom (28) of the bucket (8), which locks the tong leg. This completes the assembly process. After the directional control valve (63) has been changed over, the work equipment according to FIG. 10 can be put into operation. The dismantling of the work equipment is done in the opposite way.

Claims (6)

1. A power shovel having a working tool (7), e.g. a shovel, connected to the dipper arm via an operating joint (9) comprising joint sleeves (26) fixed to the working tool (7) and a pivot pin (25) positioned on an upper part (10) and having a driving mechanism consisting of operating cylinders (23, 24) positioned laterally of the pivot pin (25), characterised by two plate halves (29, 30) forming a mounting plate (27), on whose upper side (31) are fixed bush parts (45, 46, 47) through which the pivot pin (25) extends as well as the operating cylinders (23, 24), whereby the plate halves (29, 30) are pivotable in a clamp-like manner such that in a working position they grip behind fixing means (56 to 59) fixed to the working tool, and release the plate halves into a free space, and by an additional bolt (69, 69a, 70, 70a, 73) between the plate halves (29, 30) and the working tool (7).

2. A power shovel according to claim 1, characterised in that, for changing the working tool (7), the operating joint (9) is actuated by closing of the operating cylinder (24) connected to one of the plate halves (30), and the operating cylinder (23) of the other plate half (29) serves for opening and closing the gripping means.

3. A power shovel according to any one of claims 1 and 2, characterised in that operating joint sleeves (26) are provided on the sides (31, 32) facing the dipper arm of the mounting plate (27) which is divided into the two plate halves (29, 30) by the hinge connecting the two plate halves (29, 30) which are in mirror symmetry, which mounting plate has connecting brackets (37, 38) on its upper side for the operating cylinders (23, 24) and has recesses (51, 54) at the hinge edges (49, 50) of the plate halves (29, 30) which cooperate with each other in the gripping position for gripping projections (56, 57) of the working tool (7) provided with heads (58, 59).

4. A power shovel according to any one of claims 1 to 3, characterised in that the pivot pin (25) of the operating joint (9) forms the hinge axis of the mounting plate (27) and sub-divides the sleeves (26) of the operating joint (9) and is fixed to both hinge halves (29, 30).

5. A power shovel according to any one of claims 1 to 4, characterised in that the halves (43, 44) of the subdivided operating joint (9) surround the sub-divided brackets (37, 38) of the operating cylinders (23, 24) which are in mirror symmetry at right angles to the hinge connecting the plate halves (29, 30).

6. A power shovel according to any of claims 1 to 5, characterised by a guide bead (74) which is fixed to the working tool (7) next to the connections (56 to 59) and cooperates with the closed plate halves in readiness for gripping resulting in engagement with the connections (57 to 59).

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