COUPLING DEVICE FOR RELEASABLY COUPLING A TOOL TO A WORK MACHINE

Technical Field

The present invention refers to a coupling device for a work machine configured for releasably coupling a tool to the work machine. Further, the present invention refers to a work machine which is equipped with such a coupling device.

Technological Background

Work machines are known, in particular wheeled or tracked work machines, such as excavators and backhoe loaders, which are configured to operate a variety of interchangeable tools, such as buckets, grabs, breakers, compactors and the like. For doing so, the known work machines are equipped with a coupling device which allow for selectively and releasably coupling a tool to the work machine.

The employed coupling devices are usually attached to a movable arm of the work machine and comprise a rigid mount which constitutes a structural interface, in particular a standardized structural interface, for receiving and thus supporting a tool. In other words, the rigid mount is provided and configured for establishing a structural connection between the coupling device and a tool. The known coupling devices further comprise an actuated retaining element which is configured to selectively lock or release the structural connection between the coupling device and the tool by mechanical wedges. Since these coupling devices allow to couple or decouple a tool in a time efficient manner, in particular without requiring any manual assembly work by an operator, they are also referred to as 'quick-coupler'.

Summary

Embodiments of the present disclosure provide an improved coupling device with, among other things, an increased reliability. And an objective is to provide a work machine that is equipped with such an improved coupling device.

The improved coupling device and a machine equipped with such a device is the subject matter of the independent claims. Preferred embodiments are set forth in the present specification, the Figures as well as the dependent claims.

In a coupling device, the retaining element may be actuated by two linear actuators, in particular by two hydraulically driven cylinders, which are coupled to opposing sides of the retaining element via articulated pushing rods. By such a configuration, force transmission and distribution at the retaining element may be improved. However, during operation of such a coupling device, it may occur, for example due to wear or failure conditions, that the opposing sides of the retaining element are subjected to unequal actuating forces, for example when the amount of actuating forces exerted by the two linear actuators onto the retaining element differs among the actuators or when one side of the retaining element gets stuck. This may result in an angled position of the retaining element which may cause damage of the coupling device, in particular of its actuation mechanism, such as hydraulic seals.

Accordingly, a coupling device is provided for releasably coupling a tool to a work machine. The coupling device comprises a mount for supporting the tool and a retaining element configured to lock or release a structural connection between the mount and the tool, wherein the mount comprises at least one bearing unit configured for mounting the retaining element on the mount such that the retaining element is translationally displaceable relative to the mount along a longitudinal axis of the mount and pivotable relative to the mount around a pivot axis which is perpendicular to the longitudinal axis, and wherein the retaining element comprises at least one bearing element which has a structural configuration that limits pivoting movement of the retaining element relative to the mount around the pivot axis.

Furthermore, a work machine is provided which comprises such a coupling device for releasably coupling a tool to the work machine.

Since the proposed work machine is equipped with the coupling device as described above, technical features described herein in the context of the coupling device may refer and be applied to the work machine, and vice versa.

Brief Description of the Drawings

The present disclosure will be more readily appreciated by reference to the following detailed description when being considered in connection with the accompanying drawings in which:

Fig. 1 schematically shows a work machine equipped with a coupling device and a tool which is decoupled from the work machine;

Fig. 2 schematically shows an enlarged side view of the decoupled tool depicted in Fig. 1;

Fig. 3 schematically shows an enlarged side view of the coupling device shown in Fig. 1 in a decoupled state in which it is decoupled from the tool;

Fig. 4 schematically shows an enlarged side view of the coupling device in an engaged state in which it is structurally engaged with the tool;

Fig. 5 schematically shows an enlarged side view of the coupling device in a coupled state in which it is structurally coupled to the tool;

Fig. 6 schematically shows a perspective bottom view of a mount of the coupling device depicted in Fig. 1; Fig. 7 schematically shows an enlarged perspective view of a first bearing unit of the coupling device depicted in Fig. 1;

Fig. 8 schematically shows an enlarged perspective view of a second bearing unit of the coupling device depicted in Fig. 1;

Fig. 9 schematically shows a longitudinal cross-sectional view of a retaining element used in the coupling device in a first end position;

Fig. 10 schematically shows a longitudinal cross-sectional view of the retaining element used in the coupling device in a second end position; and

Fig. 11 shows a schematic representation of an actuator assembly of the coupling device depicted in Fig. 1.

Detailed Description

In the following, the invention will be explained in more detail with reference to the accompanying Figures. In the Figures, like elements are denoted by identical reference numerals and repeated description thereof may be omitted in order to avoid redundancies.

Fig. 1 schematically shows a work machine 10 equipped with a coupling device 12 for releasably coupling a tool 14 to the work machine 10. In the state shown in Fig. 1, the tool 14 is decoupled from the coupling device 12 and thus from the work machine 10. The coupling device 12 is provided in the form of a quick coupler, i.e. which does not require manual assembly work for coupling or decoupling a tool.

In the context of the present disclosure, the term 'work machine' refers to any machine or equipment intended to operate a tool coupled thereto. For example, such a work machine may refer to construction or heavy machinery designed for executing construction tasks. More specifically, such machines may refer to wheeled or tracked work machines, such as excavators and backhoe loaders, or the like, but are not limited thereto and may also refer to stationary machinery, such as fixed cranes. Accordingly, the term 'tool' in the sense of the present disclosure refers to any tool which can be operated by such a work machine. For example, the tool may refer to buckets, grabs, breakers, compactors and the like.

In the shown configuration, the work machine 10 is exemplarily provided as a tracked excavator. Yet, the technical features described in the following in the context of the excavator may likewise be applied to and implemented in any other suitable work machine. The basic structure of the work machine 10 is built up of a machine body 16, also referred to as 'rotating platform', which is pivotably mounted on tracks 18. The machine body 16 carries a cab 20 for an operator and supports an arm arrangement 22 which is pivotably mounted thereon and which accommodates the coupling device 12 at a distal end thereof, as can be gathered from Fig. 1. Specifically, the arm arrangement 22 comprises an arm or stick 24 which is pivotably mounted on a distal end of another arm or boom 26 which in turn is pivotably mounted on the machine body 16, wherein the coupling device 12 is provided at a distal end of the stick 24. Hydraulic actuators 28 are installed among the arm arrangement 22 and the machine body 16 to actuate and move the stick 24, the boom 26 and the coupling device 12 by hydraulic pressure from a pressure source 30, such as an engine driven hydraulic pump, responsive to operator commands received via a user input device 32, such as a joystick.

Fig. 2 shows an enlarged view of the tool 14 which, in the shown configuration, is a grab having a rigid tool body 34 on which a pair of arms 36 is pivotably mounted and actuated by hydraulic actuators 38. In a coupled state of the tool 14, i.e. in which the tool 14 is coupled and secured to the coupling device 12 for allowing proper use of the tool 14, the hydraulic actuators 38 of the tool 14 are actuated by hydraulic pressure directed thereto from the pressure source 30 accommodated in the work machine 10. For doing so, the tool 14 comprises a hydraulic power transmission interface (not shown) which is configured to, in the coupled state of the tool 14, be releasably connected to a correspondingly designed hydraulic power transmission interface (not shown) of the coupling device 12, thereby allowing the hydraulic actuators 38 of the tool 14 to be actuated by hydraulic pressure from the pressure source 30 responsive to operator commands received by the user into put device 32.

The tool body 34 comprises two parallel and in particular mirror symmetric side plates 40. As Fig. 2 shows a side view of the tool 14, only one of the two mirror symmetric side plates 40 is visible in the Figure. Each side plate 40 is provided with a first recess 42, a second recess 44 and a third recess 46, also referred to as ‘wedge receptacle’ herein, which together form a structural interface 48 of the tool 14 for structurally coupling the tool 14 to a correspondingly designed structural interface 50 of the coupling device 12.

With reference to Figs. 3 to 5, the structural and functional configuration of the coupling device 12 and its structural interface 50 for releasably coupling the tool 14 to the coupling device 12 are described. The coupling device 12 comprises a mount 52 for supporting the tool 14, i.e. which forms the structural interface 50 of the coupling device 12 for coupling the tool 14 to the coupling device 12, and hinged plates 54, also referred to as interface to the work machine, via which the coupling device 12 is fastened to the distal end of the work machine's stick 24.

The mount 52 and the hinged plates 54 may have a multi-part design, for example a two-part design, in which the mount 52 and the hinged plates 54 constitute distinct parts which may be mounted, in particular releasably mounted, to one another. Alternatively, the hinged plates 54 and the mount body 55 may constitute an integral design in which at least parts of the mount 52 and the hinged plates 54 are cast of a single piece. For mounting the coupling device 12 to the stick 24, the hinged plates 54 is provided with two mounting holes through which pins are inserted, thereby forming articulated joints 55 to pivotably attach the mount 52 to the stick 24 of the work machine 10. The mount 52 is built up of two parallel and mirror symmetric side plates 56, also referred to as base body, which are arranged at opposing sides of the mount 52. From the side plates 56, outwardly and oppositely projecting first lugs 58 and second lugs 60 are provided. In the vicinity of the first and second lugs 58, 60, the side plates 56 are connected via cross supports, extending perpendicular to the side plates 56 and structurally connecting the side plates 56, particularly for increasing rigidity and stability of the mount 52, as can be gathered from Fig. 6. The first and second lugs 58, 60 of the mount 52 are configured and designed to engage with the first and second recesses 42, 44, respectively, to structurally engage the tool 14 with the coupling device 12 as further described below.

The mount 52 further comprises a retaining element 62 which, together with the first and second lugs 58, 60, constitutes the structural interface 50 of the mount 50 which is configured to be releasably coupled to the correspondingly designed structural interface 48 of the tool 12 and thus to tightly connect the tool 14 to the coupling device 12.

The retaining element 62 is configured to lock or release a structural connection between the mount 52 and the tool 14, i.e. between their structural interfaces 48, 50. For doing so, the retaining element 62 is arranged to be movable relative to the mount 52 between a release position, as depicted in Fig. 4, and a retaining position, as depicted in Fig. 5. In the retaining position, the retaining element 62 is positioned relative to the mount 52 to secure the structural connection between the mount 52 and the tool 14. In other words, in an engaged state of the mount 52 and the tool 14, the retaining element 62 when being in its retaining position secures the structural connections between these components. In the release position, however, the retaining element 62 is positioned relative to the mount 52 such that a structural engagement between the mount 52 and the tool 14 may be set or released. In the following, a procedure of coupling the tool 14 to the coupling device 12 is described with reference to Figs. 3 and 5. For coupling the tool 14 to the work machine 10, at first, the operator operates the work machine 10 to bring the retaining element 62 into its release position as depicted in Fig. 3 which shows a decoupled state of the coupling device 12. In the context of the present disclosure, the ‘decoupled state’ refers to a state of the coupling device 12 in which it is decoupled, i.e. released, from the tool 14 and thus not engaged therewith. In other words, in this state, the structural interface of the coupling 12 and the tool 14 are not engaged and particularly spaced apart from one another.

Thereafter, the operator moves the arm arrangement 22 to position the mount 52 of the coupling device 12 over the tool body 34 such that the second lugs 60 of the mount 52 are received in the second recesses 44 of the tool 14. Then, the operator pivots the mount 52 to position the first lugs 58 into the first recesses 42, while maintaining the second lugs 60 in engagement with the second recesses 44. By doing so, the coupling device 12 and the tool 14 are brought in an engaged state as depicted in Fig. 4. In the context of the present disclosure, the ‘engaged state’ refers to a state of the coupling device 12 in which it is engaged with the tool 14, while a relative movement of the coupling device 12 relative to the tool 14 is enabled, particularly at least one rotational movement around the second lugs 60. In other words, although the coupling device 12 and the tool 14 are engaged with one another in this state, a structural connection between the structural interfaces 48, 50 of the coupling device 12 and the tool 14 can be released upon relative movement between these two components. Thus, in the engaged state, a structural connection between the coupling device 12 and the tool 14 is not fixed or secured.

With the tool 14 and the coupling device 12 in the engaged state, the retaining element 62 is then moved by an actuator assembly 64 from the release position as depicted in Fig. 4 to the retaining position as depicted in Fig. 5 to engage the retaining element 62 with the wedge receptacles 46. By doing so, the coupling device 12 is brought into a coupled state. In the context of the present disclosure, the ‘coupled state’ refers to a state of the coupling device 12 in which it is tightly and securely fixed to a tool 14. That is, in the coupled state, the structural connection between the coupling device 12 and the tool 14 is interlocked or secured. In other words, in this state, the structural connection between the coupling device 12 and the tool 14 cannot be released upon relative movement between the coupling device 12 and the tool 14, while the retaining element 62 is in its retaining position. Specifically, upon bringing the retaining element 62 in its retaining position, retaining portions 66, in particular in the form of mechanical wedges, i.e. which is wedge shaped, of the retaining element 62 which form opposing end sections thereof are placed into and thus are engaged with the wedge receptacles 46 of the tool body 34. In this way, the structural interfaces 48, 50 of the coupling device 12 and the tool 14 are form-fittingly and in particular force-fittingly connected.

The basic structure and mode of operation of such a coupling device 12 are well known to a person skilled in the art and are thus not further specified. Rather, characteristics of the mount 52 and the retaining element 62 which are interlinked with the present invention are addressed in the following under reference to Figs. 6 to 9.

In the shown configuration, the mount 52 and the retaining element 62 i.e. at least parts thereof, have a mirror symmetric design. In other words, the mount 52 and the retaining element 62 may be provided with parts for establishing the structural connection to the tool 14 which are correspondingly provided on opposing sides of these components. Thus, for avoiding a repeated description of elements and redundancies, like elements which are provided at opposing sides, in particular in a mirror symmetric manner, are indicated by identical reference signs herein, wherein reference signs which are supplemented by an apostrophe refer to elements provided at one side of the coupling device 12 which is opposed to a side at which the elements are indicated by reference signs without an apostrophe.

Fig. 6 depicts a bottom view of the mount 52 of the coupling device 12 which is shown isolated from the work machine 10. For the sake of better visualization, individual parts of the coupling device 12, such as the hinged plates 54 of the coupling device 12 as well as a bottom cover and a hydraulic power transmission interface of the mount 52, are not shown in the Figure.

The mount 52 constitutes a structural component, i.e. intended and configured for force absorption and force transmission between the arm arrangement 22 of the work machine 10 and the tool 14. In the mount 52, the retaining element 62 and the actuator assembly 64 for actuating the retaining element 62 are received and supported. Specifically, the retaining element 62 is received in the mount 52 to be movable relative to the mount 52 between its retaining position and its release position.

The actuator assembly 64 is configured to translationally move the retaining element 62 between its retaining position and its release position. For doing so, the actuator assembly comprises a first linear actuator 68 and a second linear actuator 68' arranged at opposed sides in the mount 62. The first and the second linear actuator 68, 68’ are rotatably coupled to the retaining element 62, i.e. at opposing sides thereof. Specifically, the first and the second linear actuator 68, 68’ comprise an articulating push rod 70, 70', each of which is rotatably mounted to the retaining element 62 via articulated connections 72, 72'. The push rods 70, 70’ pass through a cross wall 73 of the mount 52 in front of which the retaining element 62 is arranged. More specifically, each one of the first and the second linear actuator 68, 68’ is rotatably coupled to a respective bearing element 82, 82’ of the retaining element 62 such that a relative rotational movement is enabled between the retaining element 62 and the first and the second linear actuator 68, 68’. This is enabled by the articulated connections 72, 72’ which are specified below. In the shown configuration, the first linear actuator 68 is rotatably coupled to a first bearing element 82 and the second linear actuator 68’ is rotatably coupled to a second bearing element 82’.

The first and the second linear actuator 68, 68' are arranged parallel to one another, in particular mirror symmetric to one another. In the shown configuration, the first and the second linear actuator 68, 68’ are provided in the form of hydraulic actuators which are actuated by hydraulic pressure from the pressure source 30 responsive to operator commands received by the user input device 32. Alternatively, the linear actuators may be electrically driven.

For receiving and mounting the retaining element 62, the mount 52 comprises two distinct and spaced apart bearing units, i.e. a first bearing unit 74 and a second bearing unit 74'. The bearing units 74, 74’ are configured for mounting the retaining element 62 on the mount 52 such that the retaining element 62 is translationally displaceable relative to the mount 52 along a longitudinal axis L of the mount 52 and pivotable relative to the mount 52 around a pivot axis P which is perpendicular to the longitudinal axis L. The retaining element 62 comprises a first and a second bearing element 82, 82’ which are provided at opposed sides of the retaining element 62 and via which the retaining element 62 is mounted in the mount 52. In other words, the bearing elements 82, 82’ define and limit movement of the retaining element 62 relative to the mount 52. As such, the bearing elements 82, 82’ interact with the bearing units 74, 74’. Specifically, the bearing elements 82, 82’ have a structural configuration that limits pivoting movement of the retaining element 62 relative to the mount 52 around the pivot axis P as further described below.

In the context of the present disclosure, the term 'longitudinal axis' refers to an axis of the mount 52 along which the retaining element 62 is movable to be displaced between its retaining position and its release position. For example, the longitudinal axis L may be a long axis of the mount 52 and/or may be an axis which is parallel to a mirror plane with respect to the mirror symmetric parts of the mount 52 and/or which lies in the mirror plane. Further, in the context of the present disclosure, the ‘pivot axis’ refers to any axis which is perpendicular or substantially perpendicular to the longitudinal axis L. The pivot axis P may be arranged parallel to a mirror plane of the retaining element 62.

The first and the second linear actuator 68, 68’ are rotatably coupled to opposing sides of the retaining element 62 by virtue of the articulating push rods 70, 70'. Specifically, the first and the second linear actuator 68, 68’ are rotatably mounted on the opposing sides of the retaining element 62 such that a relative rotational movement is enabled between retaining element 62 and the first and the second linear actuator 68, 68’ around at least one axis parallel to the pivot axis P. More specifically, the connection between the linear actuators 68, 68’ and the retaining element 62 is provided such that a relative rotational movement between the first linear actuator 68 and the retaining element 62 around a first axis Pl is enabled and a relative rotational movement between the second linear actuator 68’ and the retaining element 62 around a second axis Pl’ is enabled. The first axis Pl is arranged parallel to the pivot axis P and passes through the first articulated connection 72, wherein the second axis P2 is arranged parallel to the pivot axis P and passes through the second articulated connection 72’, as can be gathered from Fig. 7 and 8.

The first and the second bearing units 74, 74’ are provided for mounting the retaining element 62 on the mount 52. For doing so, the first and the second bearing unit 74, 74’ are arranged at opposing sides of the mount 52. Specifically, the first and the second bearing units 74, 74’ are provided such that they protrude from a front end of the mount 52, in particular from the cross wall

73, in direction of the longitudinal axis L. Further, the first and the second bearing units 74, 74’ are formed by the side plates 56 of the mount 52.

In the shown configuration, the first and the second bearing unit

74, 74’ constitute slide bearings in which the retaining element 62 slides over at least one bearing or sliding surface 76, 76’, 78, 78’. In other words, by such a configuration, each one of the first and the second bearing units 74. 74’ constitute a slide bearing comprising at least one bearing or sliding surface 76, 76’, 78, 78’ engaged with the retaining element 62, in particular with a correspondingly designed bearing or sliding surfaces of the retaining element 62. In other words, in a mounted state in which the retaining element 62 is received in the bearing units 74, 74’, the retaining element 62 is designed and configured to lie on and slide over the sliding surfaces 76, 76’, 78, 78’. In this configuration, the sliding surfaces 76, 76’, 78, 78’ of the first and the second bearing unit 74, 74’ are arranged parallel or substantially parallel to the longitudinal axis L and perpendicular or substantially perpendicular to the pivot axis P.

Specifically, as can be gathered from Fig. 7 and 8, each one of the first and the second bearing unit 74, 74’ comprises a first sliding surface 76, 76’ and a second sliding surface 78, 78’ which have opposing orientations and specifically face each other. In other words, the first sliding surface 76, 76’ and the second sliding surface 78, 78’ are arranged on opposing sides such that they face each other, wherein the retaining element 62 is received between the first and the second sliding surface 76, 78, 76’, 78’, in particular such that a predefined tolerance or clearance is provided therebetween. For doing so, each bearing unit 74, 74’ comprises a first bearing arm 77, 77’, and a second bearing arm 79, 79’, wherein the first sliding surface 76, 76’ is formed at an inner surfaces of the first bearing arm 77, 77’ and the second sliding surface 78, 78’ is formed at an inner surface of the second bearing arm 79, 79’ such that the first sliding surface 76, 76’ of a first bearing arm 77, 77’ faces the second sliding surface 78, 78’ of the associated second bearing arm 79, 79’ within a bearing unit 74, 74’.

By this configuration, besides allowing the above described relative movement between the mount 52 and the retaining element 62, the bearing units 74, 74’ are configured to block a translational movement of the retaining element 62 relative to the mount 52 along the pivot axis P, in particular along both directions of the pivot axis P. Further, the bearing units 74, 74’ are configured to block a rotational movement of the retaining element 62 relative to the mount 52 around an axis being parallel to the longitudinal axis and around an axis being perpendicular to the longitudinal axis L and the pivot axis P.

Furthermore, each one of the bearing units 74, 74’ may comprise at least one guiding surface 80, 80’, respectively. In the present disclosure, the term ‘guiding surface’ refers to a surface of the bearing units 74, 74’ which is intended and configured to guide and thus limit movement of the retaining element 62 relative to the mount 52. Specifically, the guiding surfaces 80, 80’ are intended and configured to interact with at least one correspondingly designed bearing element 82, 82’ of the retaining element 62 associated thereto. During operation of the retaining element 62, the guiding surfaces 80, 80’ of the mount 52 interact with the associated bearing elements 82, 82’ of the retaining element 62 such that the bearing elements 82, 82’ may come in contact with and may slide over the guiding surfaces 80, 80’, thereby guiding the movement of the retaining element 62 relative to the mount 52. Furthermore, the guiding surfaces 80, 80’ are intended and configured to absorb forces acting upon the retaining element 62 during operation. That is, by means of the guiding surfaces 80, 80’ and the associated bearing elements 82, 82’, external forces acting upon the retaining element 62 may be transferred from the retaining element 62 to the mount 52. In case the retaining element 62 is subjected to lateral external forces, i.e. forces acting upon the retaining element 62 in a direction perpendicular to the longitudinal axis L, or torques about the pivot axis P, the retaining element 62 together with the bearing units 74, 74’ are designed and configured such that at least one bearing element 82, 82’ is pressed, pushes or hits against the associated guiding surface 80, 80’, thereby enabling to transfer these external forces into the mount 52. By doing so, damages of the actuator assembly 22 induced by unintendedly large displacements of the retaining element 62 relative to the mount 52 may effectively be prevented. Specifically, in the proposed coupling device 12, the first bearing unit 74 comprises a first guiding surface 80 associated to and/or engaged with the first bearing element 82 of the retaining element 62. The second bearing unit 74’ comprises a second guiding surface 80’ which is opposed to the first guiding surface 80 and which is associated to and/or engaged with the second bearing element 82’ of the retaining element 62. In the context of the present disclosure, by describing that a bearing element is associated to a guiding surface, it is meant that the guiding element is intended and configured to contact the guiding surface and to transfer forces therebetween during operation of the coupling device 12.

The first guiding surface 80 is arranged opposing to the second guiding surface 80’. In the shown configuration, an orientation of the first guiding surface 80, i.e. a surface normal of the first guiding surface 80, points towards the second guiding surface 80’, and vice versa. In other words, the first guiding surface 80 faces the second guiding surface 80’. In an alternative configuration, the orientation of the first guiding surface 80, i.e. the surface normal of the first guiding surface 80, may point away from the second guiding surface 80, and vice versa, while in particular the surface normal of the first guiding surface 80 and a surface normal of the second guiding surface 80’ may align with one another.

In the shown configuration, as can be gathered from Fig. 7, the first guiding surface 80 comprises a first portion 80a provided at an inner side of the first bearing arm 77 of the first bearing unit 74 facing the second bearing unit 74’ and a second portion 80b provided at the inner side of the second bearing arm 79 of the first bearing unit 74 facing the second bearing unit 74’. Accordingly, as can be gathered from Fig. 8, the second guiding surface 80’ comprises a first portion 80a’ provided at an inner side of the first bearing arm 77’ of the second bearing unit 74’ facing the first bearing unit 74 and a second portion 80b’ provided at the inner side of the second bearing arm 79’ of the second bearing unit 74’ facing the first bearing unit 74. As such, the different portions 80a, 80a’, 80b, 80b’ of the guiding surfaces 80, 80’ constitute guiding surfaces by themselves.

The first and the second guiding surfaces 80, 80’, in particular their portions 80a, 80a’, 80b, 80b’, are arranged parallel or substantially parallel to the longitudinal axis L. Further, the first and the second guiding surfaces 80, 80’, in particular their portions 80a, 80a’, 80b, 80b’, are arranged parallel or substantially parallel to the pivot axis P. The first and the second guiding surface 80, 80’, in particular their portions 80a, 80a’, 80b, 80b’, are flat or plane, i.e. has no curvature.

As can be gathered from Fig. 7 and 8, the first and the second guiding elements 82, 82’ comprise protrusions rising or protruding from a surfaces of the retaining element 62 which slide over the sliding surfaces 76, 76’, 78, 78’. Specifically, each one of the first and the second guiding element 82, 82’ comprise a first protrusion 84, 84’ and a second protrusion 86, 86’ which rise or protrude from opposing sides of the retaining element 62. The first and the second protrusions 84, 84’, 86, 86’ are also referred to as guiding portions. Accordingly, the first protrusion 84, 84’ is configured to interact and engage with the first portion 80a, 80a’ of the associated guiding surface 80, 80’ and the second protrusion 86, 86’ is configured to interact and engage with the second portion 80b, 80b’ of the associated guiding surface 80, 80’. As such, the first and second protrusions 84, 84’, 86, 86’ of the guiding elements 82, 82’ constitute guiding elements by themselves. In other words, the first and the second protrusion 84, 86 of the first guiding element 82 are configured to interact and engage with the guiding surface 80 of the first bearing unit 74 and the first and the second protrusion 84’ 86’ of the second guiding element 82’ are configured to interact and engage with the guiding surface 80’ of the second bearing unit 74’.

The guiding elements 82, 82’, in particular each one of the protrusions 84, 84’, 86, 86’ are provided with a curved guiding surface constituted by a middle portion 88, 88’ which connects a first guiding section 90, 90’ to a second guiding section 92, 92’. In this configuration, the guiding sections 90, 90’, 92, 92’ form rounded corners of the associated guiding elements 82, 82’, in particular of the protrusions 84, 84’, 86, 86’. In this way, galling or scraping of the guiding surfaces 80, 80’ by the guiding elements 82, 82’ may be prevented. Specifically, the middle portion 88 may have a curvature that is smaller than a curvature of the guiding sections 90, 90’, 92, 92’.

As set forth above, the retaining element 62 is mounted in the mount 52 via at least the first and the second bearing element 82, 82’. As such, the first and the second bearing element 82, 82’ define and limit relative movement between the retaining element 62 and the mount 52. As set forth above, the first and the second bearing element 82, 82’ are provided with a structural configuration, in particular have a geometric design, that limits pivoting movement of the retaining element 62 relative to the mount 52 around the pivot axis P, in particular while allowing pivoting movement to a predefined extent. By this configuration, the retaining element 62 is allowed to take an angled position compared to a desired neutral position in which the retaining element 62 is arranged parallel to the mount 52, in particular parallel to the cross wall 73, such that the push rods 70, 70’ are arranged perpendicular or substantially perpendicular to the retaining element 62 and thus parallel or substantially parallel to the longitudinal axis L. By being provided with the bearing elements 82, 82’, the suggested structural arrangement defines a maximal angled position, the retaining element 62 can be positioned into. In this way, the structural arrangement of the mount 52 and the retaining element 62 may prevent the retaining element 62 from taking an excessive angled position which may induce or cause damage of the coupling device 12, in particular the actuation assembly 22, such as hydraulic seals. In this way, reliability of the coupling device 12 may be increased since, even if the coupling device is subjected to a failure condition, i.e. in which the retaining element 62 takes an angled position relative to the desired neutral position during operation, e.g. due to wear of individual components of the coupling device 12, fatal or grave damages of the coupling device 12 may be averted.

More specifically, the bearing elements 82, 82’ are designed such that the retaining element 62 is pivotable relative to the mount 52 and the linear actuators 68, 68’ around the pivot axis P between a first end position and a second end position. In a state in which the retaining element 62 is positioned in the first end position, the retaining element 62 is pivoted or shifted by not more than 8° or 10° or 12° and not less than 2° or 4° or 6° around the pivot axis P relative to a state in which the retaining element 62 is positioned in the second end position. In other words, with respect to the neutral position, the retaining element 62 may be pivoted up to 4° or 5° or 6° in a first rotational direction and/or in a second rotational direction being opposed to the first rotational direction. In the context of the present invention, the term ‘end position’ refers to a position beyond which a component cannot be further moved or pivoted.

In the context of the present invention, the term “end position” refers to an angular position of the retaining element 62 relative to the mount 52 or the linear actuator 68, 68’ beyond which the retaining element 62 cannot be swived.

In Fig. 9 and 10, the coupling device 12 is depicted in a longitudinal cross-sectional view. Fig. 9 shows a state of the coupling device 12 in which the retaining element 62 is positioned in the first end position. In the state depicted in Fig. 10, the retaining element 62 is positioned in the second end position. As can be gathered from Fig. 9 and 10, the first and the second bearing element 82, 82’ are provided with a recess 93, 93’ in which a distal end section of the associated linear actuators’ push rod 70, 70’ is received and connected to the retaining element 62 via the articulated connections 72, 72’, respectively.

In the first end position depicted in Fig. 9, a first blocking portion 95 of the first bearing element 82 lies against the first linear actuator 68, in particular its push rod 70, and a second blocking portion 97’ of the second bearing element 82’ lies against the second linear actuator 68’, in particular its push rod 70’. Accordingly, in the second end position depicted in Fig. 10, a second blocking portion 97 of the first bearing element 82 lies against the first linear actuator 68, in particular its push rod 70, and a first blocking portion 95’ of the second bearing element 82’ lies against the second linear actuator 68’, in particular its push rod 70’. In the respective bearing element 82, 82’, the first and the second blocking portion 95, 95’, 97, 97’ are arranged opposed to one another. Further, the first and the second blocking portion 95, 95’, 97, 97’ constitute side walls of the recesses 93, 93’, in particular at least parts thereof, in which the push rods 70, 70’ are received. As such, the blocking portions 95, 95’, 97, 97’ are spaced apart from the articulated connections 72, 72’. By this structural configuration, the bearing elements 82, 82’ are configured to limit pivoting movement of the retaining element 62 relative to the mount 52 and the linear actuators 68, 68’.

Further, in the first and the second end position, the guiding portions, i.e. the first and second protrusions 84, 86 of the first bearing element 82 are spaced apart from the guiding surface 80 of the first bearing unit 74 or the first and second protrusions 84’, 86’ of the second bearing element 82’ are spaced apart from the guiding surface 80’ of the second bearing unit 74’.

In an alternative embodiment, the coupling device 12 may be provided such that, in the first end position and in the second end position, the guiding portion 84, 86 of the first bearing element 82 lies against the guiding surface 80 of the first bearing unit 74 and the guiding portion 84’, 86’ of the second bearing element 82’ lies against the guiding surface 80’ of the second bearing unit 74’. Specifically, in the first end position of this embodiment, the first guiding section 90 of the guiding portion 84, 86 of the first bearing element 82 may lie against the first guiding surface 80 of the first bearing unit 74 and the second guiding section 92’ of the guiding portion 84’, 86’ of the second bearing element (82’) may lie against the second guiding surface 80’. Accordingly, in the second end position of this embodiment, the second guiding section 92 of the first guiding element 82 may lie against the first guiding surface 80 and the first guiding section 90’ of the second guiding element 82’ lies against the second guiding surface 80’. In this configuration, the guiding portions of the bearing element 82, 82’ may be designed to limit pivoting movement of the retaining element 62 relative to the mount 52 around the pivot axis P. Accordingly, in this configuration, the bearing elements 82, 82’ may be designed such that, in the first and/or the second end position, the side walls of the recess 91, 91’ do not lie against the first and second linear actuator 68, 68’. Accordingly, the blocking portions 95, 95’, 97, 97’ may be omitted in this embodiment.

In the configuration depicted in Fig. 6, the first and the second bearing element 82, 82’ are designed such that a first guiding section distance DI, which in particular is a minimal distance, between the first guiding sections 90 of the first bearing element 82 and the associated second guiding sections 92’ of the second guiding element 82’ is smaller than a guiding surface distance DO, which in particular is a minimal distance, between the first and the second guiding surface 80, 80’. Further, the first and the second guiding element 82, 82’ are designed such that a second guiding section distance D2, which in particular is a minimal distance, between the second guiding sections 92 of the first guiding element 82 and the associated first guiding sections 90’ of the second guiding element 82’ is smaller than the guiding surface distance DO between the first and the second guiding surface 80, 80’. By this configuration, the retaining element 62 may be prevented from being wedged between the bearing units 74, 74’. Alternatively, the first and the second guiding section distance DI, D2 may be greater than the guiding surface distance DO.

Further, the retaining element 62 is designed such that an imaginary line, indicated by dotted lines in Fig. 6, between the guiding sections 90, 92 of the first guiding element 82 and the associated guiding sections 92’, 90’ of the second guiding element 82’ having a length of the first and second guiding section distance DI, D2; an imaginary line, indicated by a dashed line in Fig. 6, between the first and the second guiding surfaces 80, 80’ having a length of the guiding surface distance DO, and the longitudinal axis L are arranged parallel to a plane or may be arranged within a common plane.

Compared to known configurations, the proposed coupling device 12 properly works without being provided with a central guide, also referred to as "birds-beak", for guiding the retaining element and for receiving and transmitting forces to the mount. Accordingly, such a birds-beak structure may be omitted. This may be achieved by allocating the guiding and force transmitting function to the sides of the retaining element 62, i.e. the retaining portions 66, 66', in combination with the body of the coupling device 12, i.e. the slide bearing unit 74, 74'.

In the following, the structural and functional configuration of the actuator assembly 64 is specified with reference to Fig. 11 which shows a schematic representation of the actuator assembly 64. The first linear actuator 68 may include a first piston 94 received in a first hydraulic cylinder 96 as indicated by dashed lines. Accordingly, the second linear actuator 68’ may include a second piston 94’ received in a second hydraulic cylinder 96’ as indicated by dashed lines in Fig. 9. The first and the second pistons 94, 94’ are pivotably connected to the first and the second push rod 70, 70’, respectively. The first and second hydraulic cylinder 96, 96’ form static parts of the actuator assembly 22 which are mounted in fixed relation to the mount 52.

The first and the second linear actuator 68, 68’ may further comprise a first and a second biasing element 98, 98’, in particular in the form of spring coils which are arranged around the first and the second push rod 70, 70’ between the first and the second piston 94, 94’ of the linear actuators 68, 68’ and the cross wall 73. The first and the second biasing element 98, 98’ may be configured to preload or urge the retaining element 62 into its release position or its retaining position. The actuator assembly 64 further comprises a hydraulic circuit 100 for providing hydraulic pressure to the first and the second linear actuator 68, 68’, in particular to the first and the second hydraulic cylinder 96, 96’. The hydraulic circuit 100 includes a flow divider 102 connected to a supply line 104. The flow divider 102 is configured for controlling a flow of hydraulic fluid supplied to the flow divider 102 via the supply line 104 to flow simultaneously at an equal flow rate to or from each of the first and second linear actuator 64, 64’. In other words, the flow divider 102 may be configured to split a supplied hydraulic flow evenly between the first and the second hydraulic cylinder 96, 96’ such that the first and the second linear actuator 64, 64’ move in unison. In other words, the flow divider 102 is configured to equal the supplied hydraulic flow to both hydraulic cylinders 96, 96’. In case one of the hydraulic cylinders is stuck or has higher resistance, the flow divider 102 is configured to guide the hydraulic flow to the one hydraulic cylinder 96, 96’ that is subjected to higher resistance until it loosens and both hydraulic cylinder 96, 96’ can be actuated and moved simultaneously.

In the shown configuration, the flow divider 102 may be arranged to control the flow rate on a side of the first and second piston 94, 94’ at which positive pressure acts to move the retaining body 62 to the release position. In one possible alternative arrangement, the flow divider 102 may be arranged to act on the first and the second piston 94, 94’ on another side at which positive pressure acts to move the retaining body to the retaining position. In a further possible arrangement, two flow divider 102 may be arranged, each one acting on a different side of the first and the second piston 94. 94’. In each case, the flow divider 102 may be arranged to control flow in both inflow and outflow directions, to and from each hydraulic cylinder 96, 96’. The flow divider 102 may be configured, for example, as a spool type flow divider (as illustrated) or as a gear type flow divider, i.e. a pair of rotating bodies that displace, relative to each other, an equal volume of hydraulic fluid with each increment of angular motion, and which are mechanically connected together to rotate in synchrony. The flow divider 102 distributes torque applied to the retaining body 62 between the first and the second linear actuator 68, 68’, thereby ensuring that the two actuators move in synchrony so that the retaining body 62 is maintained in the neutral position, i.e. is not in an angled position. In such arrangements, the optional biasing elements 98, 98’ may also function as an equalizer, applying a restoring force that opposes unequal forces applied to the different sides of the retaining element 62 and urges the retaining element 62 towards the neutral position, i.e., a position of symmetry.

It will be obvious for a person skilled in the art that these embodiments and items only depict examples of a plurality of possibilities. Hence, the embodiments shown here should not be understood to form a limitation of these features and configurations. Any possible combination and configuration of the described features can be chosen according to the scope of the invention.

This is in particular the case with respect to the following optional features which may be combined with some or all embodiments, items and/or features mentioned before in any technically feasible combination.

A coupling device for releasably coupling a tool to a work machine may be provided. The coupling device may comprise a mount for supporting the tool and a retaining element configured to lock or release a structural connection between the mount and the tool, wherein the mount may comprise a at least one bearing unit configured for mounting the retaining element on the mount such that the retaining element is translationally displaceable relative to the mount along a longitudinal axis of the mount and pivotable relative to the mount around a pivot axis which is perpendicular to the longitudinal axis, and wherein retaining element comprises at least one bearing element which has a structural configuration that limits pivoting movement of the retaining element relative to the mount around the pivot axis, in particular during operation or proper operation of the coupling device.

The coupling device may be intended to be used in any suitable work machine configured to operate a tool, such as an excavator, but of course is not limited to this application.

Optionally, the coupling device may comprise an actuator assembly configured for translationally moving the retaining element between a retaining position and a release position. Optionally, the actuator assembly may comprise at least one linear actuator which is rotatably coupled to the at least one bearing element such that a relative rotational movement is enabled between the retaining element and the at least one linear actuator around an axis parallel to the pivot axis. For example, the actuator assembly may comprise a first and a second linear actuator which are rotatably coupled to opposed sides of the retaining element such that a relative rotational movement is enabled between the retaining element and the first linear actuator around a first axis parallel to the pivot axis and between the retaining element and the second linear actuator around a second axis parallel to the pivot axis. Optionally, the first linear actuator may be rotatably coupled to a first bearing element and the second linear actuator may be rotatably coupled to a second bearing element of the retaining element.

According to a further development, the at least one bearing unit, in particular a first and the second bearing unit, may constitute a slide bearing comprising at least one sliding surface engaged with the retaining element, in particular a bearing element thereof. Optionally, the sliding surface may be arranged parallel to the longitudinal axis and perpendicular to the pivot axis. Optionally, the first and the second bearing unit may comprise a first sliding surface and a second sliding surface of opposing orientations. In other words, the first and the second sliding surface may be arranged opposed to one another, in particular such that they face each other. Optionally, the at least one bearing unit may be configured to block at least one of a translational movement of the retaining element relative to the mount in a direction along the pivot axis; a rotational movement of the retaining element relative to the mount around an axis being parallel to the longitudinal axis; and a rotational movement of the retaining element relative to the mount around an axis being perpendicular to the longitudinal axis and the pivot axis.

Further, the first and the second guiding surfaces may be arranged parallel to the longitudinal axis and parallel to the pivot axis. Optionally, the first and the second guiding surfaces may be flat.

Alternatively or additionally, the coupling device may comprise a first bearing unit having a first guiding surface associated to a first bearing element of the retaining element and a second bearing unit having a second guiding surface which is opposed to the first guiding surface and which is associated to a second bearing element of the retaining element. Optionally, the first bearing element of the retaining element may comprise a guiding portion configured to interact or engage with the guiding surface of the first bearing unit and the second bearing element of the retaining element may comprise a guiding portion configured to interact or engage with the guiding surface of the second bearing unit.

The retaining element may be pivotable relative to the mount and/or relative to the at least one linear actuator around the pivot axis between a first end position and a second end position. Optionally, in a state in which the retaining element is positioned in the first end position, the retaining element may be pivoted or shifted by not more than 10° and not less than 4° around the pivot axis relative to a state in which the retaining element is positioned in the second end position.

In a further development, in the first and/or second end position, a blocking portion of the bearing element may lie against the linear actuator, in particular against a push rod of the linear actuator. More specifically, in the first end position, a first blocking portion of the bearing element may lie against the linear actuator and, in the second end position, a second blocking portion may lie against the linear actuator. Optionally, the second blocking portion may be arranged opposed to the first blocking portion.

Optionally, in the first and/or second end position, the guiding portion of the first bearing element may be spaced apart from the guiding surface of the first bearing unit. Alternatively or additionally, in the first and/or second end position, the guiding portion of the second bearing element may be spaced apart from the guiding surface of the second bearing unit.

Alternatively, in the first end position and/or in the second end position, the guiding portion of the first bearing element may lie against the guiding surface of the first bearing unit and the guiding portion of the second bearing element may lie against the guiding surface of the second bearing unit.

Alternatively or additionally, the first and the second linear actuator may be hydraulic actuators and the actuator assembly may comprise a hydraulic circuit for directing a hydraulic fluid to hydraulic cylinders of the first and the second linear actuator. Optionally, the hydraulic circuit may comprise a flow divider configured for controlling a flow of hydraulic fluid to flow equally to or from each of the first and the second linear actuator.

Furthermore, a work machine may be provided which may comprise an above-described coupling device for releasably coupling a tool to the work machine.

Industrial Applicability

With reference to the Figures and their accompanying description, a coupling device for a work machine and a work machine equipped with such a coupling device are suggested. The suggested coupling device may replace conventional coupling devices and may serve as a replacement or retrofit part. As described herein, in some embodiments of the present disclosure, a hydraulic quick coupler locking mechanism includes two cylinders. The hydraulic quick coupler locking mechanism includes a flow divider and a hydraulic circuit designed to equal the flow between the two cylinders to provide for simultaneous hydraulic activation of the two cylinders; where the circuit controls the hydraulic flow to the cylinder encountering more resistance to operation of the locking mechanism.