EP0555566B1 - Hydraulic coupling device to connect and disconnect the implement to an excavator - Google Patents

Abstract

Hydraulically operable coupling device for connecting and disconnecting the boom of an equipment item such as an excavator, loader or the like, in particular an articulated arm of a hydraulic excavator, to and respectively from an implement such as a bucket or the like, comprising a coupler element, which is linked to the free end section of the boom at a pivot pin, can be pivoted by means of an actuating device relative to the boom and at one of its ends is to be brought into positive-locking engagement with first coupling elements arranged on the outside of the implement, and a wedge-shaped or tapered locking element which is arranged at the other end of the coupler element, is guided parallel to the pivot pin and can be actuated by a hydraulic piston/cylinder arrangement and by means of which the coupler element is to be connected to the implement with positive locking free of play via a second implement coupling element reaching in the coupling position into the path of movement of the locking element, the locking element (12) being the wedge-shaped or tapered cylinder of the piston/cylinder arrangement (13) actuating the locking element (12), the cylinder (12) of the piston/cylinder arrangement (13) being axially displaceable, while its piston rod (14) is mounted in an axially fixed manner on the coupler element (6). <IMAGE>

Description

The invention relates to a hydraulically actuated (quick) coupling device, also referred to in practice as a quick-change device, for coupling or uncoupling the free end of the boom of an implement such as an excavator, loader or the like, in particular an articulated arm of a hydraulic excavator or from a tool such as a spoon or the like. according to the preamble of claim 1.

In addition to earth-moving equipment such as shovel or backhoe excavators, which are constantly operated with one and the same tool (which is accordingly also fixed - albeit interchangeable - on free end of the boom), tools are known, the tools of which can be converted with regard to the job to be performed, for example, to exchange a spoon for another spoon with a different working width, to arrange a backhoe bucket instead of a bucket or another tool such as to couple a demolition hammer.

In order to be able to change the tool as quickly and effortlessly as possible from a cost point of view, appropriate coupling devices of various designs have been developed over the course of time, with an adaptation between the coupling element arranged on the boom of the relevant tool and the one to be provided on the tools Coupling elements are required so that the operator of the implement in question can bring the boom provided with the coupling element from the driver's station into a corresponding relative position to the tool to be coupled, in which - ia after a different tool has been removed and uncoupled - the tool can be coupled.

In known coupling devices of the type in question, the tools are therefore provided with coupling elements which interact with correspondingly designed coupling parts of the coupling element. This is usually done when coupling. first with a "rough form fit" (i.e. with play), and only in a second step so that a play-free connection between the tool and the coupling element (and thus the boom) is achieved.

In this second step, in the case of a design of known coupling devices, a separate wedge-shaped or conical one is made in the coupling position brought about from the driver's cab Securing element manually driven laterally, which connects the coupling element of the coupling device with (at least) one coupling element of the tool in question without play. For this driving in of the securing element to be carried out with a hammer, however, the operator of the implement must leave the operator's platform or a second operator is required, which is unsatisfactory in view of a desired quick tool change.

Therefore, in particular in the case of hydraulic excavators, the wedge-shaped or conical securing element has already been actuated by means of a hydraulic piston-cylinder arrangement which is arranged parallel to the direction of movement of the securing element and connected to the securing element by means of tabs, levers or the like which are connected to one another in an articulated manner. is connected, a parallel arrangement of the piston-cylinder arrangement acting on the securing element to the direction of movement of the securing element has already been considered indispensable, because otherwise they protrude laterally too far beyond the coupling element and thus the earthworks or the like. would hinder and be at risk of damage. In such a hydraulically actuated coupling device, the cylinder is fixedly arranged in the usual way on the coupling element and the piston rod, which is axially movable when the piston is pressurized appropriately, is articulated at its free end facing away from the piston with a connecting element of the lever arrangement acting on the securing element or the like. connected.

This generic coupling device has the advantage over the coupling device described above that the securing element can also be actuated from the driver's station of the implement in question, but because of the parallelism between the piston-cylinder arrangement on the one hand and the securing element on the other hand and the associated redirection of force in the connecting elements (brackets, levers, joints) due to the moments that occur to considerable stresses and wear, especially since this area is in the dirt area in earth-moving machines. In addition, an undesired hydraulic pressure drop can lead to difficulties.

The present invention is therefore based on the object to improve the generic coupling device with simultaneous simplification in particular in that the actuating force generated by the hydraulic piston-cylinder arrangement for the securing element can attack centrally avoiding the inevitable occurring in the relevant prior art significant moments without leading to the disadvantages described above, a compact and better protected against external influences training is also sought.

This object is achieved according to the invention in that a separate securing element is no longer provided as before, but in that the securing element is a cylinder with a wedge-shaped or conical outer jacket which represents the part of the piston-cylinder arrangement which actuates the coupling element, where - Completely different from a piston-cylinder arrangement which acts only as an actuating device - the cylinder forming the securing element and accordingly correspondingly designed cylinder is axially displaceable, while its piston rod is axially immovably mounted on the coupling element.

According to a preferred embodiment of the present invention, a spring arrangement is provided, by means of which the axially movable cylinder of the piston-cylinder arrangement forming the securing element is pressed into the coupling position. For safety reasons, this type of training is extremely advantageous in order to ensure that it is hydraulic) pressure drop remains with a backlash-free connection.

In order to be able to move the securing element out of its coupling position into a retracted rest position, it is preferably provided that a first axial passage opening extends through the piston rod of the piston-cylinder arrangement containing the securing element, said opening optionally extending the pressure oil source of the piston-cylinder arrangement with the connects between the annular piston surface facing the piston rod and the (first) cylinder space lying opposite the cylinder wall, this retraction of the securing element from the coupling position in the presence of the spring arrangement described above thus taking place against the force of the spring arrangement.

Although it is theoretically conceivable to effect the insertion of the securing element into the coupling position only with a spring arrangement as described above, this is already due to the dimensioning of the spring arrangement required with such a design and also with regard to the locking forces to be applied when engaging the wedge or conical securing element less useful, so that it is further preferably provided that a second axial through hole extends through the piston rod and the piston of this piston-cylinder arrangement, which the pressure oil source of the piston-cylinder arrangement optionally with that between the free piston end face and connects the (second) cylinder space lying opposite this cylinder wall, so that in such a configuration the coupling process leading to play-free coupling can also take place hydraulically (possibly with the support of the spring arrangement).

To ensure a firm wedging between the securing element To be able to effect the coupling element of the coupling device on the one hand and the coupling element of the tool interacting therewith, a control device is preferably provided, by means of which pressure is to be applied to the second cylinder space in order to bring the securing element into its locking position.

Further preferred embodiments of the present invention are described in the subclaims.

Fig. 1

eine Seitenansicht einer erfindungsgemäßen Kupplungseinrichtung in Richtung des Pfeiles I in Fig. 2 gesehen;

Fig. 2

eine Draufsicht auf die Kupplungseinrichtung gemäß Fig. 1 in Richtung des Pfeiles II in Fig. 1 gesehen;

Fig. 3

einen Schnitt durch die Kupplungseinrichtung gemäß den Fig. 1 und 2 in Richtung der Schnittlinie III-III in Fig. 2 gesehen;

Fig. 4

eine schematische Seitenansicht einer an einem Baggerausleger und einem Löffel angeordneten Kupplungseinrichtung vor dem/beim Ankuppeln; und

Fig. 5

eine Fig. 4 entsprechende Darstellung im angekuppelten Zustand.

The invention is explained below using an exemplary embodiment with reference to a drawing. It shows:

Fig. 1

a side view of a coupling device according to the invention seen in the direction of arrow I in Fig. 2;

Fig. 2

a plan view of the coupling device according to Figure 1 seen in the direction of arrow II in Fig. 1.

Fig. 3

seen a section through the coupling device according to Figures 1 and 2 in the direction of section line III-III in Fig. 2.

Fig. 4

is a schematic side view of a coupling device arranged on an excavator boom and a bucket before / during coupling; and

Fig. 5

a corresponding Fig. 4 representation in the coupled state.

The drawing shows a coupling device designated as a whole with 1 (see FIG. 5) for coupling and uncoupling the free end of the boom 2 of a backhoe to various tools such as e.g. a spoon 3, the boom 2 in Fig. 1 omitted for the sake of clarity and in Fig. 2 has only been indicated schematically with dash-dotted lines.

Two hook-shaped first coupling elements 4 are formed on the outside of the bucket 3 facing the boom 2, just like in the case of other tools which are to be coupled optionally. In addition, the spoon 3 is provided with a second hook-shaped coupling element 5, which sits in the center of the spoon 3 and thus between the two first coupling elements 4, 4 at a distance from them.

The part of the coupling device 1 arranged on the boom 2 has a frame-shaped coupling element 6 which is pivotably mounted on the free end section of the boom 2 by means of a pivot bolt 7 extending transversely to the boom 2. In addition, the coupling element 6 has a second pin 8 arranged parallel to the first pin 7, on which a piston-cylinder arrangement 9 acts as an actuating device for pivoting into the coupling elements 4, 5 of the bucket 3 indirectly via a deflecting linkage 10 (which may also be the case could take place directly), the coupling element 6 being pivoted about the first bolt 7 by means of this piston-cylinder arrangement 9.

As can be seen from Fig. 4, the excavator operator moves the boom 2 over the bucket 3 so that the pivot pin 7 can first be hooked into the first coupling elements 4 of the bucket 3, and then swivels the coupling element 6 by means of the piston-cylinder arrangement 9 down in 5, with the spoon 3 lifting up a little.

In this (provisionally) coupled state, therefore, the first coupling elements 4 interact positively with the pivot pin 7 (if desired with an axis running parallel to it), and the second coupling element 5 partially fits positively into the front end section of the coupling element 6, without, however So far, a play-free connection between the spoon 3 and coupling element 6 has been achieved. This takes place only through a wedge-shaped securing element 12 which is laterally driven into a receptacle 11 of the coupling element 6, which is shown schematically in FIGS. 4, 5.

This securing element 12 is the wedge-shaped cylinder of a piston-cylinder arrangement designated as a whole by 13 (see in particular FIG. 3), the cylinder of the arrangement 13 forming the securing element 12 being axially displaceable in the direction of its piston rod 14 , while the piston rod 14 is axially immovable on the coupling element 6.

It can be seen that the piston-cylinder arrangement 13 containing the securing element 12 is essentially completely encapsulated in the head section of the coupling element 6, that is to say is appropriately protected and practically does not protrude laterally beyond it.

The piston rod 14 is surrounded concentrically by a compression spring 15 which is supported at one end on the end face of the cylinder forming the securing element 12 facing the piston rod 14 and at its other end on the frame 6 'of the coupling element 6.

A first axial through opening 16 extends through the piston rod 14 and connects the pressure oil source (not shown in the drawing) of the piston-cylinder arrangement 13 optionally with the annular piston surface 17 facing the piston rod 14 and the cylinder wall 18 lying opposite it, which has shrunk to zero in FIG. 3 due to the coupling state shown there, since the annular piston surface 17 bears against the cylinder wall 18.

A second axial through bore 20 extends through both the piston rod 14 and the piston 21 and connects the pressure oil source of the piston-cylinder arrangement 13 optionally to the second cylinder space 24 lying between the free piston end face 22 and the cylinder wall 23 opposite this.

As can be seen from FIGS. 2 and 3, the piston-cylinder arrangement 13 is essentially completely integrated into the head section of the coupling element 6 and surrounded by a tubular housing 25, the central section of which is assigned to the second coupling element 5 of the tool 3 to be coupled is.

The coupling device 1 operates as follows:

When the boom 2 is lowered from the approach position to the tool 3 shown in FIG. 4, the excavator operator pressurizes the first axial passage opening 16 with pressure oil before reaching the coupling position according to FIG. 5, which oil thereby passes between the annular piston surface 17 and the cylinder wall 18. while at the same time the second axial through hole 20 is opened to drain hydraulic oil. The pressure oil entering the first cylinder chamber acts on the cylinder wall 18 and presses the wedge-shaped securing element 12 formed by the cylinder of the piston-cylinder arrangement 13 against the force of the compression spring 15, which concentrically surrounds the piston rod 14 and is supported on the one hand on the securing element and on the other hand on the frame of the coupling element 6, in its decoupling position, denoted by 12 'in FIG. 3 and shown in broken lines.

In this state, the excavator operator pivots the coupling element 6 into the coupling position shown in FIG. 5, wherein first sections of the pivot pin 7 come into positive engagement with the hook-shaped first coupling elements 4 of the bucket 3 and then the coupling element 6 by means of the piston-cylinder arrangement 9 is completely lowered into the coupling position according to FIG. 5. In this position, the second hook-shaped coupling element 5 of the spoon 3 engages in the front section of the coupling element 6 (without a positive connection first) (see FIGS. 1, 2, 5).

After this position has been reached, the excavator operator switches the pressurization from the first through bore 16 to the second through bore 20, so that pressure oil enters the second cylinder space 24 while the pressure oil located in the first cylinder space flows off. The cylinder of the piston-cylinder arrangement forming the securing element 12 is shifted from its retracted decoupling position 12 'into the coupling position shown in solid lines in FIG. 3, the application of pressure oil being effected by means of a corresponding control device, so that the securing element 12 is thereby is hammered into its coupling position and now ensures a firm, play-free connection between tool 3 and coupling element 6 or boom 2.

Should there be a pressure drop or failure during operation, the pressure spring 15 nevertheless ensures that it remains with a secure, play-free connection.

Claims (9)

1. A hydraulically actuatable coupling device (1) for coupling or uncoupling the extension arm (2) of a machine such as an excavator, loader or the like, particularly an articulated arm of a hydraulic excavator, to or from a tool (3) such as a shovel, comprising a coupling element (6) articulated to the free end portion of the extension arm (2) on a pivot pin (7) and pivotable by an actuating device relatively to the extension arm (2), one end of the coupling element being adapted to bring into positive engagement with first coupling elements (4) disposed on the outside of the tool (3), the device also comprising a wedge-shaped or conical securing element (12) disposed at the other end of the coupling element (6) and guided parallel to the pivot pin (7) and actuated by a hydraulic piston and cylinder arrangement (13), the securing element being adapted to connect the coupling element (6) positively and without clearance to the tool (3), via a second coupling element (5) on the tool (3) which in the coupled position engages in the path of motion of the securing element (12), characterised in that the securing element (12) is a cylinder with a wedge-shaped or conical outer jacket and constituting that part of the piston-cylinder arrangement (13) which actuates the coupling element (5), the cylinder (12) thereof being axially movable whereas its piston-rod (14) is axially immovably mounted on the coupling element (6).
2. A coupling device according to claim 1, characterised in that a first axial passage (16) extends through the piston-rod (14) of the piston-cylinder arrangement (13) and optionally connects the pressure-oil source of the piston-cylinder arrangement (13) to the (first) cylinder chamber disposed between the annular piston surface (17) facing the piston-rod (14) and the facing cylinder wall (18).
3. A coupling device according to claim 2, characterised in that a second axial passage (20) extends through the piston-rod (14) and the piston (21) of the piston-cylinder arrangement (13) and optionally connects the pressure-oil source of the piston-cylinder arrangement (13) to the second cylinder chamber (24) disposed between the free piston end face (22) and the facing cylinder wall (23).
4. A coupling device according to claim 3, characterised in that a control device is provided for pressurising the second cylinder chamber (24).
5. A coupling device according to one or more of the preceding claims, characterised in that a spring arrangement (15) is provided for pressing the cylinder of the piston-cylinder arrangement (13), which constitutes the securing element (12), into the coupling position.
6. A coupling device according to claim 5, characterised in that the spring arrangement is a pressure spring (15) which concentrically surrounds the piston-rod (14) and one end of which is braced against the end face of the cylinder (12) facing the piston-rod (14) while its other end is braced against the frame of the coupling element (6).
7. A coupling device according to one or more of the preceding claims, characterised in that the piston-cylinder arrangement (13) containing the securing element (12) is substantially completely incorporated in the head portion of the coupling element (6).
8. A coupling device according to claim 7, characterised in that the piston-cylinder arrangement (13) is surrounded by a tubular casing (25) whose central portion facing the second coupling element (5) of the tool (3) is recessed.
9. A coupling device according to one or more of the preceding claims, characterised in that the tool (3) has a pair of hooked or dish-shaped parallel first coupling elements (4) which, when coupled, positively co-operate with portions of the pivot pin (7) or of a shaft extending parallel thereto, and in that the second coupling element (5) of the tool (3), which co-operates with the securing element (12) and is disposed substantially centrally on the tool (3), is likewise hooked or dish-shaped.

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