WO2014092656A1

WO2014092656A1 - Link member between a rotational implement or similar working tool and a hydraulic crane arm

Info

Publication number: WO2014092656A1
Application number: PCT/SI2013/000077
Authority: WO
Inventors: Branko Gril
Original assignee: Tajfun Liv, Proizvodnja In Razvoj D.O.O.
Priority date: 2012-12-12
Filing date: 2013-12-05
Publication date: 2014-06-19
Also published as: SI24257A; EP2931646B1; EP2931646A1; SI24257B

Abstract

The purpose of the invention is to create a link member (1) between a portable hydraulic crane arm (2) and a hydraulic rotator (3), which should enable reliable operation of the hydraulic crane. The pivot joint (11) of said link member (1) is fork-shaped on the side of said crane arm (2) and comprises two protrusions (111, 112) located apart from each other, which are each per se furnished with a throughout bore (111', 112'') adapted to receive a bolt (13) serving for establishing a connection with a crane arm (2). A hollow cylindrical bush (113) is inserted through said bores (111', 112') in said protrusions (111, 112) of the pivot joint (11) on the side of crane arm (2), and a bearing bush (114', 114'') is inserted therein on each side thereof, so that said bolt (13) is extending throughout said bearing bushes (114', 114'') for the purposes of establishing a pivoting interconnection between the link member (1) and the crane arm (2).˙

Description

Link member between a rotational implement or similar working tool and a hydraulic crane arm

The present invention refers to a link member between a rotational implement or a similar working tool and a hydraulic crane arm, in particular for cranes suitable for mounting onto motor vehicles.

Such inventions belong to the field of transporting and performing working operations, in particular to cranes, namely to crane arms and gripping devices in view of transmission of lifting forces.

The aim of the invention is to create a link member of a rotatable gripping device or similar working tool on the hydraulic crane arm, in particular for cranes mounted onto motor vehicles, which should increase reliability in long-term operation of such crane.

A crane arm with a link member for attaching a working accessory is described in EP 1 889 808, wherein a rotatable working accessory, in particular a gripping device suitable for gripping and displacing of timbers or similar at least approximately cylindrical objects is attached to such crane arm via the link member. Such link member comprises two pivot joints, which are spaced apart from each other in a direction of the vertical axis. Said pivot joints are located on the side of the crane arm as well as on the side of the rotator for the purposes of functioning as a Cardan pivot joint. Both rotation axis, around which pivoting is allowed, are arranged perpendicularly with respect to each other. Hydraulic conduits preferably extend along the interior of the crane arm and are directed from the crane arm towards at least approximately horizontally arranged hydraulic connectors on the crane-faced side of rotator which is arranged between said gripping device or working accessory and that side of the link member, which is faced towards said gripping device. The pivot joint of the link member, which is facing towards the crane arm, comprises two coaxially arranged bearings, which enable rotating, and hydraulic conduits are directed between said bearings towards said hydraulic conduits on said rotator, but outside of that pivot joint of the link member, which is faced towards the rotator. The main benefits of such arrangement, where the hydraulic conduits are directed towards the rotation axis and towards the gripping device or the working accessory, however passing the rotation axis at certain distance apart from it, wherein the hydraulic connectors are arranged on the crane-faced side of the link member, result in the fact that hydraulic conduits are more efficiently protected against external impacts during operation of the crane, while at the same time also undisturbed movement and rotating of the gripping device or similar working accessory is enabled. On the contrary, such concept is also connected with serious deficiencies resulting mainly from the concept of the pivot joint, which is faced towards the crane arm and is furnished with two spaced bearings, between which the hydraulic conduits are arranged. Said hydraulic conduits are usually four relatively thick flexible hydraulic hoses, which are due to unhindered movement during operation of the crane loosely placed between said bearings. Due to maneuvering capability of the crane as such and due to preventing the crane from hooking to object in the circumference thereof, said pivot joint as such should be as narrow as possible, but on the contrary, said hydraulic conduits require as much as possible space between said bearing for the purposes of unhindered movement thereof. A compromise between said contradictions leads to quite narrow bearings, and of this reason ball bearings are usually used. Roller bearings and needle bearings are wider and much more expensive, and also lead to undesired enlargement of the width of the pivot joint. Unfortunately, the ball bearings are then not rotated with appropriately high velocity, which would enable establishing of required lubricating conditions. Oh the contrary, such bearing is used for just occasionally pivoting, where the deflections from the original position i.e. the vertical plane are usually ± 15 do 45 degrees, and actual loading of the bearings during the practical exploitation of the crane is extremely inappropriate, by which also a desired lubricating is practically impossible to be achieved. A complete loading is transferred via two or three roller members within each bearing, and practically all the time via the same ones, so that the lubricant is removed from the area of these roller member in a very short time, which is still assisted by hot hydraulic conduits arranged in the adjacency thereof. Of that reason, such concept of the link member in particular by extensively used cranes leads to repeating defects, which make further exploitation of the crane impossible, until the bearings are replaced in the service station.

A further approach is described in WO 201 1/142704, where also a link member is described, via which the hydraulic rotator is connected with the crane arm. Hydraulic conduits are directed along the interior of the crane arm towards the hydraulic connectors on the rotator. The member link comprises two pivot joints, namely a bifurcated i.e. double upper pivot joint arranged on the side of the crane arm and a single pivot joint arranged on the side of the rotator, wherein both axis, of said pivot joints, around which pivoting is possible, are arranged perpendicularly with respect to each other. In order to achieve better guidance of the hydraulic conduits, the link member is furnished with a pin, which is inserted throughout both protrusions of the upper pivot joint and through both bearings, so that the geometric axis of said pin is aligned with the geometric axis of the pivot joint as such, wherein a separate guide for hydraulic circuits is arranged on said pin. Said guide is formed of an U-shaped plate, and both arms thereof are furnished with throughout openings, through which said pin is inserted. Hydraulic conduits are directed from the interior of the crane arm over said pin, more exactly between said pin and said guide, and then towards the hydraulic connectors on the rotator. Thanks to said guide, some better guidance of the hydraulic conduits is achieved, which leads to more reliable operation of the crane, but the problem of inappropriate loading and lubricating of the bearings in the pivot joint remains completely unsolved.

The present invention refers to a link member between a rotational implement or a similar working tool and a hydraulic crane arm, namely a link member, which is on the one hand pivotally connected with said crane arm and on the other hand also pivotally with a hydraulic rotator, which is connectable with each used working accessory or gripping device. Such link member comprises two pivot joints, which are located at appropriate distance apart from each other in a direction of vertical axis, namely an upper pivot joint located on the side of the crane arm and a lower pivot joint located on the side of the rotator or each working accessory, so that said pivot joints are conceived as a Cardan pivot link with two rotation axis, which allow pivoting of the link member relative to the crane arm and/or relative to the rotator and which extend perpendicularly with respect to each other. The lower pivot joint intended for pivotal interconnection of the link member with the rotator is conceived in form of an eye, which is furnished with a throughout bore, which is directed along said rotational axis of the lower pivot joint and is adapted to receive a bolt, while the upper pivot joint, which is located on the side of the crane arm and adapted for establishing a pivotal interconnection therewith, is bifurcated and comprises two protrusions, which are spaced apart from each other and are each per se furnished with a throughout bore adapted to receive a bolt serving for establishing interconnection with the crane arm, and wherein hydraulic conduits, which extend between the crane arm and the rotator, are directed between said extensions of the upper pivot joint of the link member.

In accordance with the invention, a hollow cylindrical bush is inserted through the bores in the protrusions on the upper pivot joint of the link member on the side of the crane arm, and two bearing bushes are inserted, preferably pressed, therein and are each per se located on corresponding end portion thereof, so that the bolt, which is intended for establishing a pivotal interconnection between the link member and the crane arm in the area of the upper pivot joint of the link member, is inserted through them.

In a preferred embodiment of the invention, the protrusions of the upper pivot joint are extended towards the crane arm and are at appropriate distance apart from the bush bridged by a limitation means, while simultaneously the hydraulic conduits are directed from the crane arm towards the link member and then towards to the rotator in such manner that in the area of the upper pivot joint of the link member they extend between the bush and the limitation means towards hydraulic connectors on the rotator.

Said limitation means is preferably cylindrical and extends parallel to said rotation axis of the upper pivot joint of the link member, and is in particular conceived as a pin extending throughout said protrusions and between them.

The limitation means is located at a pre-determined distance apart from the bush of the upper pivot joint as well as at a pre-determined distance apart from the vertical axis of the link member, which is defined by angle between a tangent to the limitation means on the side of said vertical axis and the vertical axis itself. In this, the distance between the limitation means and the bush is preferably 35 - 55 mm, and the angle between a tangent to the limitation means on the side of the vertical axis and said vertical axis itself is preferably 10 - 30°. Besides, a roller member can be placed around said limitation means.

Moreover, at least one lubricating device adapted for transferring lubricant towards the areas between the bearing bushes and the bolt is foreseen on the bush and/on the bolt, which is mounted on the upper pivot joint (on the side of the crane arm.

The invention will be described in detail by means of an embodiment, which is presented in the enclosed drawings, wherein

Fig. 1 is an isometric front view of a link member according to the invention in its mounted state; Fig. 2 is a front isometric view of a link member according to the invention in its mounted state;

Fig. 3 is an explosion isometric view of a separately presented link member according to the invention; and

Fig. 4 is a side isometric view of a separately presented link member according to he invention.

A crane arm 2 with a member link 1 is partially shown in Fig. 1, by means of which at a not-shown, at least partially rotatable working accessory, in particular a gripping mechanism adapted for lifting and displacing of timbers or similar approximately cylindrical objects, is attached to said crane arm 2.

Said link member 1 comprises two pivot joints 1 1, 12, which are located apart from each other in direction of the vertical axis, namely an upper pivot joint 1 1, which is located on the side of the crane arm 2, as well as a lower pivot joint 12, which is located on the side of a rotator 3 i.e. a working accessory.

Said pivot joints 1 1, 12 on the side of the crane arm 2 and the rotator 3 are conceived to function as a Cardan pivot joint. Rotation axis 1 10, 120 of both pivot joints 1 1, 12 allowing pivoting, extend perpendicularly with respect to each other.

The lower pivot joint 12 is conceived as an eye 121 with a throughout bore 122 extending along said rotation axis 120 of the lower pivot joint 12.

Between each disposable working accessory and the link member 1 a rotation unit is included, a so-called rotator 3, consisting of a stationary portion 3', which is connectable with said link member 1 and is furnished with hydraulic connectors 31, 32, 33, 34, as well as of a rotatable portion 3", to which said working accessory is connectable. Said stationary portion 3' of the rotator 3 is furnished with two eyes 35, 36, which are located at appropriate distance apart from each other and are each per se furnished with a throughout bore 35', 36', so that the lower pivot joint 12 of the link member 1 is inserted between them, wherein the pivotal interconnection between the rotator 3 and the link member 1 is established by means of a bolt 37, which is inserted within said bores 35', 36' on the eyes 35, 36 of the stationary portion 3' of the rotator 3 and at the same time also within a bore 122 on the eye 121 of the lower pivot joint 12 of the link member 1.

Three hydraulic conduits 41, 42, 43 are presented in the drawings, although in general e.g. four conduits can be placed within the crane arm 2, and extend from said crane arm 2 towards each corresponding hydraulic connectors 31, 32, 33 on the stationary portion 3' of the rotator 3, which are directed horizontally towards the crane arm 2.

The upper pivot joint 1 1 on the side of the crane arm 2 is bifurcated i.e. fork-like shaped and comprises two protrusions 1 11, 112, which are each per se furnished with a throughout bore 11 1 ', 1 12'.

Said bores 1 1 1 ', 1 12' of said protrusions 1 1 1, 1 12 extend coaxially along said rotation axis 110 of said upper pivot joint 1 10.

A hollow cylindrical bush 1 13 is inserted through said bores 1 1 1 ', 1 12' of said protrusions 1 11 , 1 12, into the interior of which two slide bearing bushes 1 14', 1 14" are tightly pressed on both end portions 113', 1 13" thereof in order to form a slide bearing, through which a bolt 13 is inserted, which serves as a complementary bearing element and which is generally used for the purposes of connecting the link 1 member with the crane arm 2 in the area of the upper pivot joint 11 of said link member 1. At least one lubricating device, which is not shown in the drawings, can be foreseen on said bush 113 of the upper pivot joint 1 1, or optionally on said bolt 13, which then serves for the purposes of transferring each lubricant towards both contact surfaces between said bearing bushes 1 14', 1 14" and the bolt 13. Those skilled in the art shall understand that said bearing bushes 1 14', 1 14" consist of appropriate material with respect to sliding and lubricating properties not only for the purposes of lubricating bushes 1 14', 1 14" during rotation relative to the bolt 13 with sufficient velocity to form a so-called lubricating wedge, but also in some different circumstances, when said bushes 1 14', 114" are just occasionally pivoted around the bolt 13 at relative small angle in the range of approximately ±15 do 45 degrees relative to the vertical axis. The compression stresses on contact surfaces between said bushes 1 14', 114" can in particular by lifting of heavier loads be pretty high, but can also be lowered by means of enlarging the length of said bushes 1 14', 114", which are however inserted within said bush 1 13 and such measure then has no impact to situation in the exterior of said bush 1 13.

For the purposes of guiding said hydraulic conduits 41, 42, 43 in the area of said link member 1, said protrusions 1 1 1, 1 12 of the upper pivot joint 1 1 are extended towards the crane arm 2 and bridged with a limitation means 14 located at appropriate distance apart from said bush 1 13 i.e. rotation axis 1 10 of the upper pivot joint 1 1.

Said limitation means 14 is preferably cylindrically shaped and extends parallel with respect to said rotation axis 1 10 of the upper pivot joint 1 1 of the link member 1. The limitation means 14 can be conceived as a pin, which extends throughout said protrusions 1 1 1, 1 12 and between them.

Said limitation means 14 is used for the purposes of guiding the hydraulic conduits 41, 42, 43 in the sense of appropriate alignment and uniformly bending thereof despite to movement of the rotator 3 towards the crane arm 2 or away from it, and simultaneously for the purposes of preventing said hydraulic conduits 41, 42, 43 from extremely bending and/or disorder. To this aim, the invention provides for a pre-determined arrangement of said limitation means 14, which is defined by means of appropriate distance a apart from the bush 1 13 of the upper pivot joint 1 1 as well as by means of appropriate distance apart from the vertical axis of the link member 1, which is defined by means of an angle φ between a tangent t to said limitation means 14 on the side of said vertical axis and the vertical axis as such. Said distance a between the limitation means 14 and the bush 1 13 is 35 - 55 mm, and the angle φ between the tangent t to the limitation means 14 and the vertical axis is 10 - 30°. A not shown roller member can be optionally placed around said limitation member 14, although the presence thereof is not required in view of realization of the invention as such.

Said hydraulic circuits 41 , 42, 43 extend from the crane arm 2 towards to the link member 1, wherein in the area of the upper pivot joint 1 1 they are located between the bush 1 13 and the limitation means 14, and further extend towards the hydraulic connectors 31, 32, 33 on the rotator 3.

Claims

PATENT CLAIMS

1. Link member (1) between a rotational implement or a similar working tool and a hydraulic crane arm (2), namely a link member (1), which is on the one hand pivotally connected with said crane arm (2) and on the other hand also pivotaly with a hydraulic rotator (3), which is connectable with each used working accessory or gripping device, wherein said link member (1) comprises two pivot joints (1 1, 12), which are located at appropriate distance apart from each other in a direction of vertical axis, namely an upper pivot joint (1 1) located on the side of the crane arm (2) and a lower pivot joint (12) located on the side of the rotator (3) or each working accessory, so that said pivot joints (1 1, 12) are conceived as a Cardan pivot link with two rotation axis (1 10, 120), which allow pivoting of the link member (1) relative to the crane arm (2) and/or relative to the rotator (3) and which extend perpendicularly with respect to each other, and wherein the lower pivot joint (12) for pivotal interconnection of the link member (1) with the rotator (3) is conceived in form of an eye (121), which is furnished with a throughout bore (122), which is directed along said rotational axis (120) of the lower pivot joint (12) and is adapted to receive a bolt (37), while the upper pivot joint (1 1), which is located on the side of the crane arm (2) and adapted for establishing a pivotal interconnection therewith, is bifurcated and comprises two protrusions (1 1 1, 112), which are spaced apart from each other and are each per se furnished with a throughout bore (1 1 1 ', 1 12') adapted to receive a bolt (13) serving for establishing interconnection with the crane arm (2), and wherein hydraulic conduits (41, 42, 43), which extend between the crane arm (2) and the rotator (3), are directed between said extensions (1 1 1, 112) of the upper pivot joint (1 1) of the link member (1), characterized in that a hollow cylindrical bush (1 13) is inserted through the bores (1 1 1 % 112') in the protrusions (11 1 , 1 12) on the upper pivot joint (1 1) of the link member (1) on the side of the crane arm (2), and two bearing bushes (114', 1 14") are inserted therein and are each per se located on corresponding end portion (1 13', 113") thereof, so that the bolt (13), which is intended for establishing a pivotal interconnection between the link member (1) and the crane arm (2) in the area of the upper pivot joint (1 1) of the link member (1), is inserted through them.

2. Link member according to Claim 1 , characterized in that the protrusions (1 1 1, 1 12) of the upper pivot joint (1 1) are extended towards the crane arm (2) and are at appropriate distance apart from the bush (1 13) bridged by a limitation means (14), and in that the hydraulic conduits (41, 42, 43) are directed from the crane arm (2) towards the link member (1) and then towards to the rotator (3) in such manner that in the area of the upper pivot joint (1 1) of the link member (1) they extend between the bush (1 13) and the limitation means (14) towards hydraulic connectors (31 , 32, 33) on the rotator (3).

3. Link member according to Claim 2, characterized in that the limitation means (14) is cylindrical and extends parallel to said rotation axis (1 10) of the upper pivot joint (1 1) of the link member (1).

4. Link member according to Claim 3, characterized in that the limitation means (14) is conceived as a pin extending throughout said protrusions (1 1 1 , 1 12) and between them.

5. Link member according to Claim 2 or 3, characterized in that the limitation means (14) is located at a pre-determined distance (a) apart from the bush (1 13) of the upper pivot joint (1 1) as well as at a pre-determined distance apart from the vertical axis of the link member (1), which is defined by angle (φ) between a tangent (/) to the limitation means (14) on the side of said vertical axis and the vertical axis itself.

6. Link member according to Claim 5, characterized in that the distance (a) between the limitation means (14) and the bush (1 13) is 35 - 55 mm, and the angle (φ) between a tangent (t) to the limitation means (14) on the side of the vertical axis and said vertical axis itself is 10 - 30°.

7. Link member according to anyone of Claims 3 to 6, characterized in that a roller member is arranged around the limitation means (14).

8. Link member according to anyone of Claims 1 to 7, characterized in that the at least one lubricating device adapted for transferring lubricant towards the areas between the bearing bushes (1 14', 114") and the bolt (13) is foreseen on the bush (1 13), which is mounted on the upper pivot joint (1 1) on the side of the crane arm (2).

9. Link member according to anyone of Claims 1 to 7, characterized in that at least one lubricating device adapted for transferring lubricant towards the areas between the bearing bushes (1 14', 1 14") and the bolt (13) is foreseen on the bolt (13), which is mounted on the upper pivot joint (1 1) on the side of the crane arm (2).

10. Link member according to anyone of the preceding Claims, characterized in that the bearing bushes (1 14', 1 14") are pressed into the bush (1 13).