DE20007050U1 - Quick coupler for clamshell buckets - Google Patents

Description

17.04.2000 00412-00 G/T/ej/bs

Liebherr-Hydraulikbagger GmbH 88457 Kirchdorf/Iller

Quick coupler for orange peel grapple

The present invention relates to a quick-change device for multi-shell grabs, the gripper shells of which are pivotably mounted on a shell carrier. The present invention further relates to a multi-shell grab for such a quick-change device, with a shell carrier on which the gripper shells of the multi-shell grab are pivotably mounted. Finally, the invention relates to a load beam for such a quick-change device.

Quick-change systems for multi-shell grabs are known, for example, from EP 0 728 874 A2 or DE 196 43 892 A1. The grab shells of a multi-shell grab usually have crossbars that are connected to pivoting levers of a shell carrier, so that the grab shells are pivotably mounted on the shell carrier and can be opened and closed accordingly. With the known quick-change systems, the entire shell carrier can be uncoupled from the crossbars of the grab shells and coupled to them. This means that only one shell carrier is required, which can be coupled to various grab shells of different widths.

These quick-change systems can be improved in several respects. For example, it is desirable to be able to use an ejector to eject sticky material in narrow gripper shells, which has not been satisfactorily solved in the known quick-change systems. Furthermore, an improvement in the rigidity of the entire arrangement is desirable, since the previous quick-change systems, which have to be designed to suit the narrowest shell to be used, did not give the wide gripper shells the necessary rigidity.

The present invention is therefore based on the object of creating an improved quick-change device for orange peel grabs of the type mentioned, an improved orange peel grab for such a quick-change device and an improved load beam for such a quick-change device, which avoid disadvantages known from the prior art. In particular, an arrangement which is easy and safe to operate is to be created, which gives the grab shells great rigidity and stability.

According to the invention, this object is achieved by a quick changer of the type mentioned at the outset with a central carrier, which can be connected at one end to a gripper suspension and at its other end has an adapter that can be coupled to the shell carrier, a plurality of pressure fluid piston-cylinder units for opening and closing the gripper shells, which are pivotally connected at one end to the central carrier or the gripper suspension and can be coupled at their other end to the gripper shells, wherein the gripper shells are assigned coupling units into which the pressure fluid piston-cylinder units can be coupled, and a cylinder centering device which automatically centers the pressure fluid piston-cylinder units with a precise fit relative to the coupling units when the adapter is coupled into the shell carrier.

The entire shell carrier is not uncoupled from the gripper shells and coupled to them. The separation point is further up, in particular there is a central separation point between the adapter and the shell carrier as well as further separation points between the gripper shell side ends of the pressure medium

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Piston cylinder units and the respective gripper shells. Each multi-shell grapple has its own individual shell carrier, in particular shell carriers of different widths can be provided for gripper shells of different widths. This makes it possible to achieve a higher inherent rigidity of the overall construction, particularly with large cutting width ranges, since the support width of the shell carrier does not need to be aligned with the narrowest gripper shell.

In particular, the quick changer according to the invention is characterized in that pre-positioning of the pressure fluid piston-cylinder units is provided during coupling. With the help of the cylinder centering device, the pressure fluid piston-cylinder units can be inserted precisely into the coupling units on the gripper shell side. In particular, they are positioned in such a way that the coupling units can be locked without further handling. This makes one-man operation possible; it is not necessary for one person to position the pressure fluid piston-cylinder units and for another person to drive in locking bolts or the like. In particular, the pre-positioning of the pressure fluid piston-cylinder units makes handling inside the gripper shells and moving back and forth with the quick changer unnecessary, which eliminates the corresponding risk of injury and significantly increases safety.

In a further development of the invention, the pre-positioning of the pressure fluid piston-cylinder units can be achieved by stops against which the pressure fluid piston-cylinder units can come to rest when the quick changer is in the uncoupled state. The stops can be formed on the central support. As a result of gravity, the pressure fluid piston-cylinder units, which are pivotably connected above the stops, are pressed against the stops so that the pressure fluid piston-cylinder units assume a defined position relative to the central support. Due to the exact pre-positioning relative to the central support, the pressure fluid piston-cylinder units also assume the desired defined position relative to the gripper shells.

-A-

The stoppers are preferably designed in such a way that they pre-position the pressure fluid piston-cylinder units in two directions, namely, firstly, they specify the pivoting position of the pressure fluid piston-cylinder units in the circumferential direction around their upper pivot axis and, secondly, they position the pressure fluid piston-cylinder units transversely to this. This means that the pressure fluid piston-cylinder units can be pivoted with their upper ends like a ball joint in order to compensate for any misalignment, and yet precise pre-positioning is still achieved.

In a further development of the invention, the cylinder centering device is designed to be elastically flexible. This prevents kinematic collisions, which would be possible with a rigid design of the centering device. With normal forces on the pressure fluid piston-cylinder units when the quick changer is disengaged, the cylinder centering device holds the pressure fluid piston-cylinder units precisely in the specified position; however, with large forces, the cylinder centering device can give way, so that damage to the cylinder centering device or the pressure fluid piston-cylinder units is avoided. On the other hand, the elastic flexibility of the pre-positioning allows fine adjustment of the pressure fluid piston-cylinder units by hand, or to assist with coupling the pressure fluid piston-cylinder units into the gripper shells. In particular, the pre-positioning of the pressure fluid piston-cylinder units can be achieved by rubber buffers that are attached to the central support of the quick changer.

Preferably, an adapter centering device is provided for the adapter of the central carrier of the quick changer for precisely centering the adapter relative to the shell carrier. In particular, complementary fitting surfaces are provided on the adapter and the shell carrier, which slide on each other when the adapter is coupled into the shell carrier.

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In order to reliably enable the coupling of the pressure fluid piston-cylinder units into the gripper shells and to be able to carry this out largely automatically, in a further development of the invention, guide surfaces can be provided on the coupling units provided on the gripper shell side, along which the pressure fluid piston-cylinder units can slide into their respective locking position. In particular, the coupling units can be arranged directly on the crossbars of the gripper shells, so that the crossbars form guide surfaces to improve the coupling ability. Preferably, guide surfaces extending transversely to the crossbars of the gripper shells are provided, between which the pressure fluid piston-cylinder units can slide into the coupling units with their ends on the gripper shell side. The guide surfaces mentioned prevent the pressure fluid piston-cylinder units from being able to pivot away transversely to their main pivoting direction, i.e. along the crossbars of the gripper shells.

In order to enable the piston-cylinder units to be moved into the coupling units provided on the grab shell side in a defined manner, the latter are preferably assigned coupling stops against which the pressure fluid piston-cylinder units can be moved into their locking position. The coupling stops can expediently be formed by trough-shaped guide plates that can be attached to the corresponding cross members of the grab shells. The coupling stops can be used to compensate for uneven extension of the pressure fluid piston-cylinder units. The coupling positions of the pressure fluid piston-cylinder units can be moved hydraulically, even if the individual pressure fluid piston-cylinder units extend asynchronously to one another. This enables the driver of the corresponding excavator to carry out the grab shell or tool change completely alone. The quick coupler can be moved into the corresponding grab shell to be coupled from the excavator operator's seat, whereby all parts to be coupled can be moved hydraulically into their coupling position. The excavator operator only needs to get out to lock the corresponding couplings.

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In a further development of the invention, the coupling units for the pressure fluid piston-cylinder units are each designed as an integral unit free of loose or removable parts. This improves handling, and necessary coupling parts such as bolts or the like cannot be lost.

The coupling of the piston-cylinder units to the gripper shells or, if applicable, to corresponding pivot levers of the shell carrier, which are connected to the gripper shells, can be accomplished in various ways. Preferably, the pressure fluid piston-cylinder units are bolted to the gripper shells. In a further development of the invention, bolt locking units are provided for locking the pressure fluid piston-cylinder units, each of which has a displaceably mounted locking bolt and a bolt drive for extending and retracting the locking bolt. The bolt locking units can in principle be provided on the pressure fluid piston-cylinder units themselves, so that they move into corresponding recesses on the gripper shells. Preferably, however, the bolt locking units are arranged on the gripper shell side. The locking bolts move into complementary recesses at the ends of the pressure fluid piston-cylinder units. Due to the bolt drive provided, it is not necessary to use a hammer to drive in the locking bolts; this is done by the corresponding bolt drive. Preferably, the bolt locking units each have a locking bolt that extends to one side and enters an eyelet at the end of the corresponding pressure fluid piston-cylinder unit. Preferably, the corresponding eyelet of the piston-cylinder unit does not have a joint bearing. A rigid bushing can be provided to accommodate the locking bolt. The lack of a joint bearing makes it easier to hit the recess in the eyelet of the piston-cylinder unit, since twisting of such a joint bearing is impossible.

The bolt drive can be designed in different ways. Preferably, a drive spindle is provided which is in screw engagement with the respective locking bolt and is rotatably and axially fixed. By turning the drive spindle,

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The locking bolt moves in and out via the drive spindle. According to one embodiment of the invention, the drive spindle can be operated at its end facing away from the locking bolt. The drive spindle is preferably accessible through a through-hole in the locking bolt, so that the drive spindle can be operated from the front end of the locking bolt, i.e. from the end of the locking bolt with which it moves into the eye of the pressure fluid piston-cylinder units. The drive spindle expediently has a key section for its operation, e.g. in the form of a polygon, onto which a hand crank or the like can be placed in a form-fitting, rotationally fixed manner.

Advantageously, the thread of the drive spindle, which engages with the locking bolt, is designed to be self-locking, so that the locking bolt is held in both its locked and unlocked position.

In order to reliably prevent unintentional uncoupling, a bolt lock is preferably provided to lock the locking bolt in its locked position. This can be achieved by a positive locking of the locking bolt, e.g. by a pin that radially engages in a recess such as a groove in the peripheral surface of the bolt. Preferably, however, the bolt lock is designed in such a way that it acts on the bolt drive and blocks it. In particular, a locking screw that can be screwed into the locking bolt can be provided, which prevents the drive spindle from being screwed into the locking bolt and the bolt from being moved into its unlocked position. The locking screw can preferably be screwed directly into the thread of the locking bolt, into which the drive spindle would also move.

In order to securely lock the locking bolt in its locked position even under very rough conditions, a locking device can be provided to secure the bolt lock in its locking position.

-8th-

Double security is provided, which secures the bolt lock, which in turn secures the locking bolt. Preferably, the locking device for securing the bolt lock is designed to be positively locked. Preferably, locking means are provided, e.g. in the form of a spring ring, which lock into place and secure the bolt lock when it is in its locking position. The described double security, i.e. the locking device for securing the bolt lock, achieves particular advantages independently of the previously described design of the quick coupler, which can also be used with differently designed quick couplers. In particular, increased safety is achieved against unintentional uncoupling, even under the most difficult operating conditions. A particularly advantageous design of the locking device for the bolt lock consists in that a spring ring is arranged in a corresponding groove in the peripheral surface of the locking screw or in the peripheral surface of the screw-in opening for the locking screw and, when the locking screw reaches the locking position, engages in a complementary recess such as a groove or a step in the peripheral surface of the screw-in opening for the locking screw or in the peripheral surface of the locking screw. Before this position is reached, the spring ring is pressed back into the groove in which it is arranged, so that the locking screw can be screwed in and out.

In a further development of the invention, the bolt locking units are arranged on the orange peel grab in such a way that they are accessible from the outside of the orange peel grab, in particular through a recess in the grab shells. According to one embodiment of the invention, the recess can be secured or covered with a removable sheet. After removing the sheet, the bolt locking unit can be knocked out through the outer wall of the orange peel grab, e.g. in order to be able to knock out the bolt locking unit as a whole if it has become stuck due to rust. Accordingly, even a defect, jamming or rusting of the drive cannot put the bolt locking unit out of operation permanently.

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In a further development of the invention, a bolt locking unit is also provided for locking the adapter to the shell carrier, which has at least one displaceably mounted bolt and a bolt drive for extending and retracting the bolt. Preferably, two coaxially arranged locking bolts that can move in opposite directions are provided. The bolt drive can consist of a drive spindle, the opposite ends of which are in screw engagement with the two locking bolts in such a way that when the drive spindle is rotated, the locking bolts are moved in different directions. At least one of the locking bolts can have a through-hole so that the drive spindle is accessible from the outside through the bolt, e.g. in order to be able to place a key or a hand crank on the drive spindle.

According to a preferred embodiment of the invention, the bolt locking unit is designed asymmetrically such that the drive spindle can only be operated from one side. In particular, the through-holes in the locking bolts can be closed with different locking screws so that the operator can only operate one of the two locking screws with his operating tool. In particular, the through-hole of one of the locking bolts can be closed with a locking screw with an internal hexagon and the through-hole of the other locking bolt can be closed with a locking screw with an external hexagon. Accordingly, the threaded spindle can only have an operating section on the side from which it is accessible, which can be coupled with a corresponding tool such as a hand crank. This makes it possible to achieve a simpler design of the threaded spindle on the other side.

The locking bolts, which are guided axially displaceably, can be secured against rotation in various ways. A preferred embodiment of the invention consists in providing guide bolts as anti-twisting devices, which in turn are axially fixed by locking screws. The guide bolts

can have flattened guide surfaces in order to be able to absorb higher forces via these flat surfaces. This reduces wear. The separate design of guide bolts and locking or locking screws allows the guide bolts, which are preferably designed as stepped bolts, to be positioned more precisely using fitting holes and to be fixed without play by axial clamping using the locking screws. Overall, this design allows the locking bolts to absorb significantly higher torques.

The bolt locking unit for locking the adapter can be arranged on the shell carrier so that the locking bolts can move into complementary locking recesses in the adapter. Preferably, however, the bolt locking unit is provided on the adapter itself. Corresponding bolt recesses are arranged in the shell carrier into which the locking bolts can move from the adapter. This means that not every shell carrier needs to be provided with its own bolt locking unit.

Preferably, the bolt locking unit for locking the adapter is also provided with a bolt lock, in particular with a double safety device against unintentional release of the bolt locking unit as described above.

The quick coupler is also advantageously characterized by the fact that the hydraulic circuit for operating the gripper shell mechanism is provided solely on the side of the quick coupler, so that no hydraulic hoses or the like need to be coupled when coupling and uncoupling the quick coupler from the orange peel grapple. This makes coupling and uncoupling the quick coupler significantly easier and faster.

With regard to the orange peel grapple for the quick changer, the above-mentioned object is thus achieved according to the invention in that the peel carrier has a

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ter complementary coupling part for coupling the adapter, coupling units for coupling the pressure fluid piston-cylinder units are connected to the gripper shells and the coupling units each have a bolt lock with a slidably mounted bolt and a bolt drive for extending and retracting the bolt.

Preferably, the coupling part for coupling the adapter can have a centering recess that is open on one side and a locking recess for receiving the locking bolt with which the adapter is locked to the coupling part. In particular, the centering recess and the locking recess can be arranged on a common straight line along which the adapter can be inserted into the coupling part.

With regard to the load beam for the quick changer, the above-mentioned object is achieved in that the load beam has a coupling part complementary to the adapter for coupling the adapter and in particular trough-shaped recesses for receiving the gripper shell-side ends of the pressure fluid piston-cylinder units, which are designed in such a way that the pressure fluid piston-cylinder units can be moved against this as a stop and are secured against movement transversely to their longitudinal axis.

The pressure fluid piston-cylinder units can therefore be pushed into the corresponding recesses on the load beam, preferably without their own locking mechanism, in the manner of a pressure rod, which prevents the pressure fluid piston-cylinder units from moving sideways or slipping away. This prevents uncontrolled swinging of the pressure fluid piston-cylinder units when the gripper rotary drive is activated, which significantly increases safety. On the other hand, the pressure rod-like support of the load beam by the pressure fluid piston-cylinder units gives the load beam stability. The recesses for supporting the pressure fluid piston-cylinder units are expediently arranged on the load beam in such a way that the cylinder centering device pre-positions the pressure fluid piston-cylinder units in such a way that

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These can be automatically retracted into the recesses with a precise fit as soon as the adapter on the central support of the quick coupler is retracted into the coupling part of the load beam.

By providing a separate load beam, which can be quickly and easily coupled to the quick coupler, it is prevented that lifting ropes and the like are improperly mounted on the orange peel grapple, especially when the orange peel grapple is open, which has already led to serious accidents.

The invention is explained in more detail below using preferred embodiments and associated drawings. In the drawings:

Fig. 1: A perspective view of a clamshell grapple with a quick coupler according to a preferred embodiment of the invention, wherein the quick coupler is uncoupled from a shell carrier of the clamshell grapple,

Fig. 2: A perspective view of the clamshell grapple from Figure 1, with the quick coupler being inserted into the shell carrier,

Fig. 3: A perspective view of the clamshell grab from Figure 1, with the quick coupler with its central carrier retracted into the shell carrier, but the cylinder piston units not yet coupled,

Fig. 4: A schematic front view of the clamshell grapple according to the previous figures, with the quick coupler coupled to the grapple shells,

Fig. 5: A side view of the clamshell grapple with the coupled quick coupler,

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Fig. 6: A schematic front view of the clamshell grab similar to Fig. 4, with the grab shells opened,

Fig. 7: A perspective detailed view of a coupling unit which is attached to the crossbar of a gripper shell and is intended for coupling one of the piston-cylinder units, in a partial section,

Fig. 8: A perspective detail view of the coupling unit from Fig. 7,

Fig. 9: A perspective detail view of the quick changer from the previous figures, showing a cylinder centering device for the pre-positioning of the piston-cylinder units,

Fig. 10: A perspective sectional view through the central carrier of the quick coupler, showing the bolt locking unit for locking the central carrier of the quick coupler to the shell carrier of the clamshell grapple,

Fig. 11: A schematic representation of a load beam that can be coupled to the quick coupler according to the previous figures,

Fig. 12: A schematic, perspective view of an adapter and the complementary coupling part of the shell carrier according to another embodiment of the invention,

Fig. 13: A perspective view of a five-jaw grab in which the piston-cylinder units are not hinged to the grab suspension as in the previous versions, but to the central support of the quick coupler,

Fig. 14: A perspective sectional view of a bolt locking unit with a bolt lock according to an alternative embodiment of the invention,

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Fig. 15: A schematic representation of a centering bolt of the quick coupler according to an alternative embodiment of the invention,

Fig. 16: A partial section of a bolt locking unit for locking a piston-cylinder unit according to an alternative embodiment of the invention,

Fig. 17: A partial sectional view of a bolt locking unit similar to Figure 16 according to an alternative embodiment of the invention,

Fig. 18: A schematic representation of a bolt lock according to an alternative embodiment of the invention,

Fig. 19: A sectional view of a locking bolt with a locking screw for locking the locking bolt according to a preferred embodiment of the invention, wherein the locking screw is loosened,

Fig. 20: A sectional view of the locking bolt of Figure 19, with the locking screw shown in its bolt locking position, and

Fig. 21: A sectional view of a bolt locking unit for locking the central carrier of the quick coupler to the shell carrier of the clamshell grab according to another preferred embodiment of the invention.

As shown in Figure 1, the quick coupler 1 has a central support 2 which has an elongated, beam-shaped extension and runs essentially vertically when aligned as intended. At its upper end, the central support 2 is connected to a gripper suspension 3, with a rotary drive (not shown separately) being connected between the gripper suspension 3 and the central support 2 in order to be able to rotate the central support 2 about its vertical axis. The gripper suspension 3 is pivotally connected to the boom of an excavator in the usual way.

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Two piston-cylinder units 4 extend laterally along the central support 2 on diametrically opposite sides thereof, the upper ends of which are pivotably connected to the upper end of the central support 2 or to a rotatable section of the gripper suspension 3. In the embodiment shown, the piston-cylinder units 4 are pivotally connected to the central support 2 or to a rotatable section of the gripper suspension 3 with their cylinders and the piston rods point towards the gripper shell 5. This arrangement can be reversed if necessary. Preferably, however, the piston-cylinder units 4 are installed in the position shown, so that the narrower, more space-saving piston-cylinder rods are located in the area of the gripper shell 5.

At its lower end, the central support 2 has an adapter 6 which can be inserted and coupled into a complementary coupling part 7 of the shell support 8. The coupling part 7 is formed by a box-shaped head part of the shell support 8 which has a recess complementary to the adapter 6 and is designed as a sheet steel construction in the embodiment shown. The adapter 6 and the corresponding recess in the head piece of the shell support 8 have mutually complementary fitting surfaces along which the adapter 6 can slide into the shell support 8 and is centered relative to it.

The adapter 6 of the central carrier 2 has at its lower end, as shown in Figures 9 and 10, a head piece 9 which extends transversely to the longitudinal axis of the carrier 2 and in which a bolt locking unit 10 is provided for locking the adapter 6 to the shell carrier 8. A transversely extending cylindrical through-hole 11 is formed in the head piece 9, in which two locking bolts 12 are seated so as to be longitudinally displaceable. The locking bolts 12 themselves have a threaded hole extending in their longitudinal direction, with which they are seated on opposite ends of a drive spindle 13. By turning the drive spindle 13, the locking bolts 12 can be moved in and out in opposite directions in order to lock the adapter 6 to the head piece of the shell carrier 8. The head piece of the shell carrier 8 has for this purpose on opposite sides

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each have a locking bore 14 into which the locking bolts 12 can be inserted (see Figure 1).

An alternative embodiment of the bolt locking unit 10 is shown in Fig. 21. The two locking bolts 12, which are arranged coaxially and can be moved axially in the cylindrical through-hole 11, are threadedly engaged on opposite ends of the drive spindle 13, as in the previously described embodiment. By turning the drive spindle 13, the locking bolts 12 can be moved in and out in opposite directions. In contrast to the previously described embodiment, the drive spindle 13 can only be operated from one side; it has a coupling section 59 on only one side, to which a drive such as a hand crank can be coupled (see Fig. 21). The opposite side of the drive spindle 13 can simply be cut to length. This means that the bolt locking unit 10 can only be operated from one side, namely the correct side. The latter is also ensured by the fact that on the side opposite the coupling section 59 of the drive spindle 13 the through hole 11 is closed with a screw plug 60 for which the operator does not have a suitable tool. In particular, a screw plug in accordance with DIN 906 with a hexagon socket can be provided as the screw plug 60. This means that only a screw plug with an external hexagon and a molded-on locking or locking projection needs to be used, as shown in Fig. 21 on the right-hand side.

The bolt locking unit 10 according to Fig. 21 is further characterized by the axial guidance or anti-twisting of the locking bolts 12. As the figure shows, both locking bolts 12 have axially extending groove-shaped recesses 61 on their peripheral side. Guide bolts 56 are seated in these, which have flattened guide surfaces 57 on which the side walls of the grooves 61 are guided. The guide bolts 56 are seated in fitting holes formed in the head piece 9, so that the guide bolts 56 project radially into the through hole 11. The fitting holes have a shoulder, so that the guide bolts 56, which are designed as stepped bolts, can be fitted with a corresponding

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corresponding shoulder (cf. Fig. 21). The guide bolts 56 are secured with locking screws 62, in particular they are clamped axially against the corresponding shoulder of the fitting holes so that they are fixed without play. The locking screws 62 are preferably designed to be identical to the locking screw 60 in one of the locking bolts 12. The closing of one of the locking bolts 12 by the special locking screw mentioned and the anti-twisting or axial guidance of the locking bolts each by a guide bolt which is clamped by a separate locking screw of the type described bring with it particular advantages regardless of the other design of the quick coupler according to the invention. In particular, significantly higher torques acting on the locking bolt can be absorbed. Furthermore, cost savings can be achieved by using the locking screw described and by the simpler design of the threaded spindle and the locking bolt.

Above the locking bolts 12, a rigid centering bolt 15 is provided on the central support 2, the longitudinal axis of which extends parallel to the common longitudinal axis of the locking bolts 12 and which protrudes on opposite sides of the central support 2 (see Figure 10). To accommodate the centering bolt 15, the head piece of the shell support 8, into which the adapter 6 can be inserted, has centering recesses 16 that are open at the top in the manner of an elongated hole that is open on one side. As Figure 1 shows, the flanks of the centering recesses 16 widen in a funnel shape towards their open side, so that the adapter 6 can be inserted into the shell support 8 even in the event of misalignment. The centering recesses 16, which taper towards their base, center the centering bolt 16 when it is fully inserted, as shown in Figures 2 and 3. As soon as the adapter 6 is completely inserted into the head piece of the shell carrier 8, the locking bolts 12 are extended into the corresponding locking holes 14 so that the central carrier 2 is coupled and bolted to the shell carrier 8. In order to avoid excessive surface pressure, the centering bolt 15 can have flats on its circumference with which it sits in the centering recesses 16 (see Fig. 15).

To couple the piston-cylinder units 4 to the gripper shells 5, these have corresponding coupling units 17 (see Figure 7) which are arranged on the crossbeams of the gripper shells 5. Each of these coupling units 17 has a bolt locking unit 18, each with a locking bolt 19 which can be extended and extended on one side and retracted by a drive spindle 20. The basis of the bolt locking unit 18 is a tube 21 which has a continuous inner longitudinal groove. The tube 21 and thus the bolt locking unit 18 extends parallel to the crossbeam of the gripper shells 5 and is attached directly to the outside of the corresponding gripper shells 5 approximately in the lower third of the crossbeam. A spiral-shaped groove is arranged on the inside of this tube 21, which enables lubrication of the locking bolt 19. A pin 22 is pressed radially into the locking bolt 19, which serves as a peripheral projection and slides like a slot nut in the inner longitudinal groove of the tube 21 and prevents the bolt 19 from turning relative to the tube 21. The drive spindle 20 is supported axially in both directions and causes the bolt to retract or extend by means of a rotary movement. The axial support of the drive spindle 20 is achieved on the one hand by a corresponding annular contact surface on the tube 21 and on the other hand by a support disk 23, which is held relative to the tube 21 by a locking ring 24 (see Figure 7). The drive spindle 20 sits with a radially projecting shoulder between the contact surface and the support disk. If the locking bolt 19 can no longer be operated, e.g. due to corrosion caused by insufficient lubrication, it can be knocked out together with the drive spindle 20 after removing the locking ring 24 and the support disk 23. For this purpose, a corresponding recess, which is closed by the support disk 23, is provided in the wall of the gripper shell 5.

The axial movement of the locking bolt 19 is limited on the one hand by the pin 22 striking the bearing plate of the gripper shell 5 and on the other hand by the frontal contact with the end spindle collar of the drive spindle 20.

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As an additional anti-twisting device, the locking bolt 19 can preferably have a flat surface 25 on the circumference at its extending end, which interacts with a corresponding counterpart 26 on the bearing plate 27, into which the locking bolt 19 can move.

As Figure 7 shows, the coupling units 17 have two bearing plates 27 arranged parallel to one another and spaced apart from one another, which extend perpendicular to the longitudinal axis of the respective cross-member away from the latter. The end eye of the piston rod of the piston-cylinder unit 4 can be inserted between these two bearing plates 27. The bearing plates 7 form lateral guides that prevent the piston rod from being pushed away when coupling, e.g. by the extending bolt.

The insertion of the ends of the piston rods of the piston-cylinder unit 4 into the coupling units 17, i.e. between the two bearing plates 27, is facilitated by the peripheral surfaces of the cross members 29, which form guide surfaces 30 for the piston-cylinder units 4.

A stop plate 31 is provided beneath each locking bolt 19, against which the end of the respective piston rod can be moved and which defines the coupling position of the corresponding piston rod (see Figure 7). Overall, the receptacle of the coupling units 17 for the ends of the piston rods is designed in a trough-shaped manner, so that the piston-cylinder unit 4 can be hydraulically moved into the coupling unit 17 for coupling.

In order to be able to automatically move the piston-cylinder unit 4 precisely into the gripper shell-side coupling unit 17, a cylinder centering device 32 is provided on the central support 2. As shown in Figure 9, two rubber buffers 33 are attached to the central support 2 at a distance from each other on the sides facing the piston-cylinder unit 4, against which and between which the piston-cylinder units 4 come to rest. This means that the piston-cylinder

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units 4 are pre-positioned in such a way that the piston rods exactly hit the coupling units 17 when extended.

The gripper shells 5 are pivotably mounted on the shell carrier 8 via bolts and are constantly connected to one another by a synchronous coupling (not shown in detail). The shell carrier 8 can advantageously be designed in different shell widths in order to achieve greater rigidity in accordance with the width of the gripper shells 5.

The quick coupler 1 can best be coupled to the gripper shells 5 when the gripper shells 5 are closed, but if necessary also when the gripper shells 5 are open, preferably in the working position on plan. The adapter 6 is initially located, as shown in Figure 1, approximately 500 mm vertically above the shell carrier 8. The piston-cylinder units 4 and the locking bolts 12 on the adapter 6 as well as the locking bolts 19 on the coupling units 17 are initially fully retracted. The adapter 6 is now aligned so that a colored marking 34 on the front side of the rigid centering bolt 15 points to the side of the gripper shells 5 from which the crank is to be turned, i.e. the bolt locking units 10 and 18 are to be operated. This saves the worker from having to lock from two sides later. The adapter 6 is now inserted into the shell carrier 8 until the upper rigid centering bolt 15 is fully seated in the corresponding contour of the shell carrier 8. Both piston-cylinder units 4 are now extended by the grab closing function. The rubber buffers 33 screwed to the side of a flange plate 35 pre-position the piston-cylinder units 4 in a certain angular position so that the piston rod eyes initially slide on the bearing plate or cross-beam 29 of the grab shells 5 so that they can be extended to the two stop plates 31. There they are then expediently retracted 1 to 2 mm by briefly operating the grab opening function and depressurized so that the bolt locking units can then be locked. To do this, the excavator operator operates the drive spindles 13 and 20 of the corresponding bolt locking units 10 and 18 by turning a hand crank.

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The locking bolts 12 and 19 are then locked to prevent the locks from being released accidentally.

For this purpose, bolt locks 36 are provided for each of the locking bolts. According to a preferred embodiment of the invention (see Figures 19 and 20), a locking screw 37 can be screwed into the end of the respective locking bolt 12 or 19 opposite the drive spindle. When screwed in, the locking screw 37 prevents the drive spindle from being screwed into the respective locking bolt and thus the locking bolt from being retracted. As Figure 19 shows, a positive locking device for the locking screw 37 is provided as a double security feature, which is designed as a latching mechanism. The locking screw 37 is held in its end position by a locking ring 38, which sits in a recess in the through-hole 40 of the respective locking bolt 12 or 19. For this purpose, the locking screw 37 also has a circumferential recess 41, which in the end position of the locking screw 37 is located opposite the recess 39 on the bolt side, so that the spring-loaded locking ring 38 can engage. The torque required to unscrew the locking screw 37 is set by the design of the shape of the recess 41 on the locking screw 37 and the preload force of the locking ring 38. The locking ring 38 can be designed not only as a snap ring, but also as a rectangular ring or as another suitable spring element, e.g. in the form of a clip.

Instead of the locking ring 38, a spring-loaded pressure piece can also be provided. As shown in Figure 14, a pin 42 can be slidably accommodated in a radially extending bore 43. It is acted upon by a spring 44 and pre-tensioned towards the locking screw 37 in order to engage in a circumferential groove when the locking screw is in the appropriate position (see Figure 14).

In the embodiment of the locking screw 37 shown in Figure 19, the locking ring 38 can be removed when the locking screw 37 is unscrewed in the locking position.

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bolt 12 or 19 remain. It is also possible that the locking ring 38 remains in the recess 41 of the locking screw 37, which is designed as an annular groove.

According to a further embodiment of the invention, the drive spindle 13 or 20 can also be acted upon directly as a locking device in order to prevent rotation thereof. As Figure 18 shows, a positively acting lock 46 can be brought into locking engagement with the actuating part 45 of the drive spindle. In the embodiment shown, the actuating part 45 of the drive spindle is designed as a hexagon and is used to attach a hand crank with which the drive spindle can be rotated. The lock 46 is preferably designed as a rocker arm which can be pressed against the actuating part 45 with a locking section complementary to the latter. A spring load is provided for this purpose.

As shown in Figures 7 and 10, the actuating part 45 of the drive spindle 13 and 20 is formed at a front end of the drive spindle, which in each case enters the corresponding locking bolt 12 or 19. The actuating part 45 is actuated through the locking bolts, i.e. through the through holes formed therein. According to another embodiment of the invention, which is shown in Figure 17, the actuating part 45 of the drive spindle can also be provided at the ends facing away from the locking bolt. This embodiment is particularly suitable for locking bolts 19 that only extend on one side and are mounted on the gripper shell side. As a result, the actuating part 45 of the drive spindle 20, which may protrude through the support disk 23, can be actuated from the outside, i.e. through the side wall of the gripper shells.

In order to secure the locking bolts 12 and 19 against twisting, they can have a longitudinal groove 47 on their outer circumference, as shown in the embodiment according to Figure 16. A projection 48, in particular a screw, projecting radially inwards from the receiving bore, engages in the longitudinal groove 47 in the form of a slotted nut, so that twisting of the locking bolt is prevented.

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The longitudinal groove 47 is preferably designed as a blind groove in both directions, so that the maximum travel of the locking bolts is limited at the same time. It is particularly advantageous that the screw 48 can be easily unscrewed in order to remove the locking bolts, for example if the drive spindle jams.

However, the design shown in Figure 17 with a longitudinal groove formed in the tube 21 is particularly advantageous for the gripper shell-side bolt locking units 18, since the locking bolts 19 accordingly do not have to have a groove on their circumference, which would quickly become dirty, especially in the dirt-prone area of the gripper shells.

As Figures 1 to 6 show, with the described design of the quick changer 1, an ejector 49 can be arranged in a simple manner. Due to the special design of the quick changer 1, the ejector 49 can be attached to the tray carrier 8. Such an ejector is particularly advantageous for smaller trays, e.g. with a tray width of 400 to 600 mm, since these small trays tend to collect sticky material in them.

The quick changer 1 is also characterized in that a separate load beam 50 can be coupled to the central carrier 2 instead of the gripper shell 5. In particular, the load beam is only locked to the central carrier 2 via the bolt locking unit 10 in the head piece of the adapter 6. For this purpose, the load beam 50 has a coupling part 51 that is complementary to the adapter 6, which is designed exactly like the coupling part 7 of the shell carrier 8 and into which the adapter 6 can be inserted accordingly.

Furthermore, the load cross member 50 has two cup-shaped recesses 52, each spaced symmetrically from the coupling part 51, which are open upwards, i.e. towards the piston-cylinder units 4 (see Figure 11). The recesses 52 form a positive guide for the two piston-cylinder units 4, which move into the recesses 52 after the load cross member 50 is coupled to the central carrier 2.

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and drive against them as a stop. The recesses 52 fix the lower ends of the piston-cylinder units 4 against lateral swinging out in order to prevent uncontrolled swinging out when the gripper rotary drive is actuated, thereby considerably increasing safety. In addition, the compression rod-like retraction of the piston-cylinder units 4 into the recesses 52 of the suspension of the load crossbeam 50 gives additional stability.

Advantageously, there are no load hooks on the rest of the gripper mechanism of the quick-change device 1, so that the worker is not tempted to guide lifting gear through the half-open gripper shells and attach it to the quick-change device 1 at another point. The load crossbeam 50 has a central load hook 53, which is aligned with the longitudinal axis of the central support 2, as well as load hooks 54 projecting to the sides, which are preferably arranged in fours in a rectangle, so that, for example, the pipes can be positioned precisely during pipe-laying work. The various load hooks on the load crossbeam 50 enable the attachment of the lifting gear to be individually adapted to the respective load lifting case (see Figure 11).

An alternative embodiment of the adapter 6 of the central carrier 2 of the quick coupler 1 is shown in Figure 12. The upper rigid bolt 15 is omitted in this embodiment. The lateral guidance between the adapter 6 and the shell carrier 8 is achieved by a square fit. The adapter 6 has pairs of opposing fitting surfaces 55 symmetrical to a plane through the longitudinal axis of the bolt locking unit 10, which interact with complementary fitting surfaces formed therein when the adapter 6 is inserted into the coupling part 7 of the shell carrier 8 and center the adapter 6 relative to the shell carrier 8. The bolt locking unit can be designed as in the embodiment of the adapter 6 according to Figures 1 to 10.

Figure 13 shows another embodiment of the quick coupler 1, in which it is coupled to a four-jaw grab. Accordingly, four piston-cylinder units are provided for opening the individual shells. In contrast to the

In the previously described embodiment of the quick changer according to Figures 1 to 10, the piston-cylinder units 4 are pivotally connected directly to the central support 2 so that the latter can be separated from the gripper suspension 3 with the piston-cylinder units 4. The cylinder centering device for pre-positioning the piston-cylinder units 4 is not shown in detail in Figure 13.

Claims (25)

1. Quick changer for multi-shell grabs, the gripper shells ( 5 ) of which are pivotably mounted on a shell carrier ( 8 ), with a central carrier ( 2 ) which can be connected at one end to a gripper suspension ( 3 ) and at its other end has an adapter ( 6 ) which can be coupled to the shell carrier ( 8 ), a plurality of pressure fluid piston-cylinder units ( 4 ) for opening and closing the gripper shells, which are pivotally articulated at one of their ends to the central carrier ( 2 ) or the gripper suspension ( 3 ) and can be coupled at their other end to the gripper shells ( 5 ), wherein the gripper shells ( 5 ) are assigned coupling units ( 17 ) into which the pressure fluid piston-cylinder units ( 4 ) can be coupled, and a Cylinder centering device ( 32 ) which automatically centers the pressure fluid piston-cylinder units ( 4 ) with a precise fit relative to the coupling units ( 17 ) when the adapter ( 6 ) is coupled into the shell carrier ( 8 ). 2. Quick changer according to the preceding claim, wherein the cylinder centering device ( 32 ) has stops ( 33 ) against which the pressure fluid piston-cylinder units ( 4 ) are pressed by gravity, wherein the stops ( 33 ) are preferably fastened to the central carrier ( 2 ). 3. Quick coupler according to one of the preceding claims, wherein the cylinder centering device is designed to be elastically flexible. 4. Quick changer according to one of the preceding claims, wherein an adapter centering device ( 15 , 16 ; 55 ) is provided for accurately centering the adapter ( 6 ) relative to the shell carrier ( 8 ), preferably formed by complementary fitting surfaces on the adapter and the shell carrier. 5. Quick changer according to one of the preceding claims, wherein the coupling units ( 17 ) for the pressure fluid piston-cylinder units ( 4 ) are assigned guide surfaces ( 30 ) along which the pressure fluid piston-cylinder units ( 4 ) can slide into their respective locking position. 6. Quick changer according to one of the preceding claims, wherein the coupling units ( 17 ) are assigned coupling stops ( 31 ) for the pressure fluid piston-cylinder units, against which the pressure fluid piston-cylinder units ( 4 ) can be moved into their locking position. 7. Quick changer according to one of the preceding claims, wherein the coupling units ( 17 ) for the pressure fluid piston-cylinder units ( 4 ) are each designed as an integral unit free of loose, removable parts. 8. Quick changer according to one of the preceding claims, wherein bolt locking units ( 18 ) are provided for locking the pressure fluid piston-cylinder units ( 4 ), each having a displaceably mounted locking bolt 19 and a bolt drive ( 20 ) for extending and retracting the locking bolt ( 19 ). 9. Quick coupler according to the preceding claim, wherein the bolt drive has a drive spindle ( 20 ) which is in screw engagement with the respective locking bolt ( 19 ) and is rotatably mounted axially fixed. 10. Quick coupler according to one of the preceding claims, wherein a bolt locking unit ( 10 ) is provided for locking the adapter ( 6 ) to the shell carrier ( 8 ), which has at least one displaceably mounted locking bolt ( 12 ) and a bolt drive ( 13 ) for extending and retracting the locking bolt ( 12 ). 11. Quick changer according to one of the preceding claims, wherein two coaxially arranged locking bolts ( 12 ) which can be moved in opposite directions are provided and the bolt drive has a drive spindle ( 13 ) which is in screw engagement with the two locking bolts ( 12 ) in such a way that when the drive spindle ( 13 ) rotates, the locking bolts ( 12 ) are moved in opposite directions. 12. Quick coupler according to the preceding claim, wherein the drive spindle ( 13 ) can be actuated through a recess in one of the locking bolts ( 12 ), preferably from only one side of the bolt locking unit ( 10 ). 13. Quick coupler according to one of claims 8 to 12, wherein a bolt lock ( 35 ) is provided for locking the locking bolts ( 12 ; 19 ) in their respective locking position, preferably being able to be brought into a position blocking the bolt drive ( 13 ; 20 ), wherein in particular a locking screw ( 37 ) that can be screwed into the respective locking bolt ( 12 ; 19 ) and preferably a particularly positive locking device ( 38 ) is provided for securing the bolt lock ( 36 ) in its locking position. 14. Quick coupler according to one of claims 8 to 13, wherein the locking bolts ( 12 ) are secured against rotation by a guide bolt ( 56 ), preferably with flattened guide surfaces ( 57 ), wherein the guide bolts ( 56 ) are preferably in turn axially fixed by separate locking screws ( 62 ). 15. Quick coupler according to one of claims 8 to 14, wherein the bolt locking units ( 10 ; 18 ) including the bolt drive ( 13 ; 20 ) are designed to be removable. 16. Quick changer according to one of claims 8 to 14, wherein the bolt locking units ( 10 ; 18 ) are accessible from an outside of the multi-shell grab, in particular through a recess in the shell carrier ( 8 ) or the grab shells ( 5 ). 17. Quick changer according to one of the preceding claims, wherein between the quick changer ( 1 ) and the multi-shell gripper, only one bolt lock ( 10 ) is provided between the adapter ( 6 ) and the shell carrier ( 8 ) and one bolt lock ( 18 ) of each of the pressure fluid piston-cylinder units ( 4 ) relative to the gripper shells ( 5 ). 18. Quick coupler according to one of the preceding claims, wherein a hydraulic circuit for actuating the gripper shells ( 5 ) is arranged solely on the side of the central support ( 2 ), such that the quick coupler ( 1 ) can be coupled to the multi-shell grapple free of hydraulic circuit couplings. 19. Quick changer according to one of the preceding claims, wherein the pressure fluid piston-cylinder units ( 4 ) are free of articulated bearings at their gripper shell-side ends, in particular have rigid bushings for receiving locking bolts. 20. Quick changer according to one of the preceding claims, wherein a separate load cross member ( 50 ) can be coupled, which has a coupling part ( 51 ) complementary to the adapter ( 6 ) for coupling the adapter ( 6 ) and preferably cup-shaped recesses ( 52 ) for receiving the ends of the pressure fluid piston-cylinder units ( 4 ), such that the pressure fluid piston-cylinder units ( 4 ) move with their ends into the receptacle ( 52 ) and are supported against it in the manner of a pressure rod. 21. Multi-shell gripper for a quick changer according to one of the preceding claims, with a shell carrier ( 8 ) on which gripper shells ( 5 ) are pivotally mounted, wherein the shell carrier ( 8 ) has a coupling part ( 7 ) complementary to the adapter ( 6 ) for coupling the adapter ( 6 ), coupling units ( 17 ) for coupling the pressure fluid piston-cylinder units ( 4 ) are connected to the gripper shells ( 5 ), and the coupling units ( 17 ) each have a bolt lock ( 18 ) with a displaceably mounted locking bolt ( 19 ) and a bolt drive ( 20 ) for extending and retracting the bolt. 22. Multi-shell grab according to the preceding claim, wherein guide surfaces ( 30 ) for introducing the pressure fluid piston-cylinder units ( 4 ) into the coupling units ( 17 ) are attached to the gripper shells ( 5 ), in particular are formed by cross members ( 29 ) of the gripper shells ( 5 ). 23. Multi-shell grab according to one of the preceding claims, wherein stops ( 31 ) for the gripper shell-side ends of the pressure fluid piston-cylinder units ( 4 ) are arranged such that they position the pressure fluid piston-cylinder units ( 4 ) with a precise fit for coupling in the coupling units ( 17 ), in particular are attached to the crossbar ( 29 ) of the gripper shells ( 5 ). 24. Orange peel grapple according to one of the preceding claims, wherein the coupling part ( 7 ) for coupling the adapter ( 6 ) has a centering recess ( 16 ) open on one side and a locking recess ( 14 ) for receiving a locking bolt ( 12 ). 25. Load beam for a quick changer according to one of the preceding claims, with a coupling part ( 51 ) complementary to the adapter ( 6 ) for coupling the adapter ( 6 ) and preferably cup-shaped recesses ( 52 ) for receiving the gripper shell-side ends of the pressure fluid piston-cylinder units ( 4 ), which are designed such that the pressure fluid piston-cylinder units can be moved against the recesses as a stop and are secured against movement transversely to their longitudinal axis.