Excavating – Combined or convertible – Having quick-connect coupling
Reexamination Certificate
2000-05-25
2002-05-14
Novosad, Christopher J. (Department: 3671)
Excavating
Combined or convertible
Having quick-connect coupling
C414S686000, C414S723000
Reexamination Certificate
active
06385872
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a rapid coupling for connection of an implement to an operating arm and similar, particularly a shovel arm, and the related connecting strap, with at least one pair of lock pins that are movably guided toward each other in alignment and that can be moved toward and away from each other by a drive and that penetrate into an aligned lock hole in the implement in their extended lock position.
Excavators are used for various tasks where there is a need for quick changes of the implements coupled with the boom, such as trench scoop, grabs, hydraulic hammers, wrecking arms and similar, for performance of various tasks. “Implements”, in this connection, also includes implement adaptors, shovel drag bearings and similar.
To connect implements to operating arms, various rapid couplings have already been proposed. Thus, for example, DE-PS 25 11 819 shows a rapid coupling in which the implement is linked through pairs of lock pins, on the one hand, to the end of the shovel arm, and on the other, to be able to swing horizontally, to a connecting strap, where the latter can be operated by means of a pivoted lever mounted on the shovel arm through a hydraulic cylinder to swing the implement, and the lock pins form the swing axis for the work implement. To retract and extend the lock pins, a relatively complicated articulated lever with a linked hydraulic cylinder is provided, and the rapid coupling is relatively expensive overall.
Furthermore, a rapid coupling is known from DE-U-93 15 868 that is integrated into an implement adapter, to couple the corresponding implement to the implement adapter. Such an implement adapter has a disadvantageous impact on the maximum useful load and resultant costs; in addition, changes in the geometry of the implement coupling are possible to only a limited extent.
The known rapid couplings need improvement with regard to their ease of handling. In particular, the coupling of the implement is laborious and generally must be manually assisted, in order to be able to guide the lock pins into their current lock position in the lock holes. But this places the corresponding person in the danger zone of the excavator.
SUMMARY OF THE INVENTION
This invention therefore relates to an improved rapid coupling of the type mentioned at the beginning, that avoids the disadvantages of known rapid couplings. In particular, the rapid coupling should be improved with regard to its handling.
According to the invention, this task is solved with a rapid coupling of the type mentioned at the beginning in that pre-centering device are provided to pre-center the retracted lock pins with the lock holes.
An automatic alignment device for the lock pins and the lock holes is provided on the implement, at least to the extent that extension of the lock pins into their lock position is possible. The pre-centering is handled with the lock pins still fully retracted, before they are extended in the pre-centered position. Complete centering can be effected by extending the lock pins, for example, by means of a corresponding conical shape of the lock pins or funnel-shaped introduction bevels on the lock holes. Based on the pre-centered self-alignment of the rapid coupling by means of a movement of the operating arm relative to the implement to be coupled, no manual alignment is necessary. This substantially increases safety since there is no reason to remain in the work area of the excavator.
As a further development of the invention, the pre-centering device form a stop, against which the operating arm can run during its movement relative to the implement. As soon as the coupling section that accepts the lock pins has run against the stop, it is in the coupling position, i.e., the lock pins align with the lock holes. The stop works diagonally to the direction of movement of the lock pins. During coupling, the movement of the operating arm relative to the implement is vertical to the direction of extension of the lock pins, so that the proper position, aligned with the lock holes, is achieved.
A guide to the lock holes is provided particularly for the coupling section on which the lock pins are arranged, where the guide is advantageously formed vertically to the lock holes and forms a stop for the coupling section with the lock pins in said coupling position. While traveling along the guide due to the movement of the operating arm relative to the implement, a stable position corresponding to the coupling position results during the lowering of the guide, in which position the lock pins are aligned with the lock holes. The boom, particularly the end of the corresponding shovel arm or the pertinent connecting strap are placed on the guide, in a particularly simple manner, where the coupling section automatically enters the correct coupling position with the lock holes due to the back and forth motion on the guide.
Pursuant to a preferred embodiment of the invention, the pre-centering device is formed as a web-shaped guide projection, particularly guide strips, arranged in pairs in an implement receptacle in which the coupling section surrounding the lock pins penetrate during coupling. The guide projections project preferably in the direction of motion of the lock pins from the surface of the implement surrounding the lock pins. To achieve the most precise pre-centering possible, each of the lock pins are preferably assigned such a guide projection. The guide projections are particularly marked vertically around the lock holes so that upon pressing the coupling section downward with the lock pins on the projection guides, the pins slide into the proper coupling position. The guide projections or tangents are preferably parallel to each other.
To simplify the insertion of the coupling section with lock pins into the corresponding receptacle on the implement, insertion bevels, acting like funnels, are provided in the further development at the coupling receptacle of the implement and/or at the coupling section surrounding the lock pins. The insertion bevels that, for example, can be formed as a phase on the corresponding edge sections, taper in the direction of insertion of the coupling section into said receptacle on the implement.
The rapid coupling can, in principle, be formed separately from the operating arm, for example, they may be integrated into an implement adapter connected with the operating arm. Preferably, however, the rapid coupling is integrated into the operating arm, particularly its shovel arm, and the related connecting strap. The corresponding implement is therefore coupled directly to the operating arm without a spacer. An adapter, that causes a higher maximum useful load, is not necessary which significantly reduces the price. Another advantage is the ability to change the geometry of the coupling. The distance between the two coupling axes can therefore be changed simply and adjusted to the kinetic requirements, such as, for example, an altered angle or increased force. The lock pins for this are inserted directly into a coupling section of the operating arm, particularly the end sections of the shovel arm and the related connecting strap. Two parallel lock pin pairs are expediently provided that simultaneously act as the hinge pins of two parallel swivel axes for the implement to be coupled. In particular, one pair of pins are placed in the end section of the shovel arm and one pair of pins in the end section of the related connecting strap.
The drive for the extension and retraction of the lock pins can be formed in various manners. Preferably, the lock pins are guided in a rotation-resistant manner into the coupling holes of the corresponding coupling section and provided with left- and right-handed threads into which one spindle connecting the two lock pins is screwed. The spindle can be connected with a drive unit that can actuate the spindle. Preferably, a manual crank drive unit can be mounted on the spindle. If necessary, a motor drive for the spindle can also be provided. Through the simple, slender formation o
Mieger Rolf
Zitterbart Thomas
Dilworth & Barrese LLP
Liebherr-Hydraulikbagger GmbH
Novosad Christopher J.
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