Excavating – Combined or convertible – Having quick-connect coupling
Reexamination Certificate
2002-03-11
2004-11-09
Will, Thomas B. (Department: 3671)
Excavating
Combined or convertible
Having quick-connect coupling
C037S417000
Reexamination Certificate
active
06813851
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a quick coupling for coupling a tool to the boom of a hydraulic excavator and the like having a quick coupling part at the boom side and a quick coupling part at the tool side, which can be latched to one another via a pair of spaced latching axles, and a power circuit coupling, in particular a hydraulic coupling, for coupling a power connection at the tool side to a power connection at the boom side, wherein the power circuit coupling has a power coupling part at the boom side and a power coupling part at the tool side, which are arranged at the quick coupling part at the boom side or at the quick coupling part at the tool side such that they automatically couple with one another as soon as the two quick coupling parts are pivoted together about a first of the two latching axles into their latching position.
Quick couplings of the pivot type are widespread in hydraulic excavators since they allow a simple and fast changing of different tools such as hydraulic grabs, ditch cleaning shovels, grab tongs and the like. Initially, only one of the two latching axles need to be positioned and brought into engagement for coupling. This can advantageously be a transverse bolt which is hung into a hook-like eyelet on the opposite coupling part. Then the coupling part at the boom side can be pivoted relative to the tool about the latching axle already brought into engagement to hereby find the latching position in which the second latching axle can be latched. The latter is as a rule formed by a pair of latching bolts which can move apart and into corresponding latching bores at the opposite quick coupling part.
Such a fast coupling of the pivot type is known from WO 91/01414 in which an automatic hydraulic coupling is provided which automatically couples a power circuit at the boom side to a power circuit at the tool side when the two quick coupling parts are pivoted together. There are two power coupling parts provided of which one is secured to the quick coupling part at the boom side and the other to the quick coupling part at the tool side, and indeed such that the two power coupling parts are moved towards one another and brought into engagement when the two quick coupling parts are pivoted together about the already latched latching axle. One of the two power coupling parts is movably mounted at the corresponding quick coupling part to compensate the circular movement of the quick coupling parts during the pivoting together.
This known quick coupling is, however, not sufficient in a number of aspects. The power coupling parts do not couple cleanly when the quick coupling parts are moved together so that oil leaking and thus a contamination of the soil can occur. Due to tilting of the power coupling parts, these are subject to great wear and can even be damaged.
SUMMARY OF THE INVENTION
It is therefore the underlying object of the present invention to provide an improved quick coupling of the kind first mentioned which avoids the disadvantages of the prior art and advantageously further develops the latter. In particular, an improved arrangement of the power coupling should be provided which allows a leak-free and defect-free coupling of the power circuits at the boom side and at the tool side.
In accordance with the invention, this object is solved by a quick coupling as described herein. Preferred embodiments of the invention are also described herein.
In accordance with the invention, the power coupling parts are moved towards one another in an exactly linear manner. A linear guide is provided for the power coupling parts which forces the power coupling parts into a relative movement with respect to one another along a straight line against the circular pivot movement. To allow the compensation of the pivot movement, at least one of the two power coupling parts is mounted at the corresponding quick coupling part movably relative thereto. It is, however, provided in a further development of the prior art that the movably mounted power coupling part compensates the pivot movement during the moving together of the quick coupling parts and moves precisely such that an exact linear movement takes place between the two power coupling parts.
In a further development of the invention, the linear guide has at least one guide element at the boom side and at least one guide element at the tool side which enter into engagement with one another on the closing of the power circuit coupling before the two power circuit coupling parts, in particular their connection connectors, enter into engagement with one another. The linear guide therefore enters into and out of engagement on the pivot movement of the two quick coupling parts about the already latched first latching axle such as the power coupling parts. The engagement of the guide elements of the linear guide takes place, however, before the engagement of the connection connectors of the power coupling parts such that the linear guide of the power coupling parts is ensured from the start. No tilting can take place and a precise linear movement is ensured over the whole coupling path of the power coupling parts. The guide elements of the linear guide are therefore in particular components formed separately from the actual power coupling elements, i.e. the connector members. They are, however, preferably fixedly arranged at the power coupling parts or can be moulded to these.
The linear guide can generally be made in different manners. Optionally, a cam track can be provided for the movably mounted power coupling part or for the movably mounted power coupling parts. A cam-like control of the movement of the movable power coupling part(s) can also be provided. In a further development of the invention, however, there are preferably provided as guide elements at least one guide bolt at one of the power coupling parts and at least one guide bore at the other power coupling part. The guide bolt is pushed into an exact fit into the complementary guide bore when the power coupling parts are moved together, whereby a linear movement is ensured. Preferably, a pair of guide bolts spaced from one another and associated guide bores are provided, with the connection connectors being able to be arranged between the guide bolts or guide bores respectively. The guide bolts extend with their longitudinal axes parallel to the direction in which the connector connections can be pushed onto one another. As connection connectors, the power coupling parts can have female and male connector members known per se which can be pushed into one another.
The guide bolt(s) of the linear guide preferably have a special shape which prevents a tilting during insertion into the complementary guide bore. In particular, each of the guide bolts can have a rounded head, a cylindrical guide section and a constriction which is provided between the head and the cylindrical guide section. In the region of the constriction, the guide bolt has a diameter reduced with respect to the head or with respect to the guide section. The rounded head can also be inserted into the guide bore with a slight angular offset. An alignment or a compensation of the angular offset takes place when the cylindrical guide surface axially spaced from the bolt head likewise comes into engagement with the guide bore.
At least one of the two power coupling parts is movably mounted relative to the associated quick coupling part. Preferably only one is movably mounted while the other is rigidly secured to the other quick coupling part. In this way, a simple arrangement is achieved which nevertheless allows the required compensation of the pivot movement.
The movability of the mounting of the corresponding power coupling part is preferably formed in a multi-axial manner. In particular the mounting of the power coupling part can allow at least one tilting movement about an axis parallel to the first latching axle and a movement in a direction perpendicular to the first latching axle. It preferably also permits a pushing movement parallel to the first latching
Mieger Rolf
Zitterbart Thomas
Dilworth & Barrese LLP
Liebherr-Hydraulikbagger GmbH
Petravick Meredith
Will Thomas B.
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