US-12623887-B1 - Load weighing link member on a crane arm

US12623887B1US 12623887 B1US12623887 B1US 12623887B1US-12623887-B1

Abstract

The present disclosure refers to a link member on an arm of a crane, which is pivotable around the horizontal axis (x) connected to said arm of said crane by means of a pivot joint, and is also pivotable around a further horizontal axis (y) perpendicular to the horizontal axis (x), wherein the link member is connected to a grabber furnished with a rotator for controlled rotation of the grabber around the vertical geometric axis (z). The purpose of the present disclosure is to provide accurate weighing of a free hanging load held by the grabber during transportation of the load, wherein said link member is configured to facilitate controlled rotation of the grabber around the substantially vertical geometric axis (z) despite inertial forces, which occur due to the acceleration or deceleration of the load when being rotated around said substantially vertical axis (z). In particular, link member comprises an elastically deformable area arranged between said pivot joints and is deformable depending on stresses to which said link member is subjected, which is caused by the weight of the load. The weight of each load is determined on the basis of deformations within said elastically deformable area of the link member, which are detected by means of suitably arranged sensors.

Inventors

Anton UMEK
Boris JERMAN
Mitja GLIHA
Matej Petek
Iztok Span

Assignees

TAJFUN PLANINA PROIZVODNJA STROJEV, D.O.O.

Dates

Publication Date: 20260512
Application Date: 20220725
Priority Date: 20210901

Claims (9)

1 . A load weighing link member on a crane arm, comprising: a first eye furnished with a first bore on a first terminal end, the first eye extending in a first direction along a first substantially horizontal geometric axis (x); a second eye furnished with a second bore on a second terminal end, the second eye extending in a second direction along a second substantially horizontal geometric axis (y) which is perpendicular to said first substantially horizontal geometric axis (x), wherein said first and second eyes are firmly connected with each other via a central area which is mechanically rigid and elastically deformable; a link member is adapted to form a connection which is freely pivotable around each of said horizontal axles (x, y), wherein link member is freely pivotable around said first horizontal axis (x) via a first pivot joint of the link member connected to the arm of the crane, wherein the link member is freely pivotable around said second horizontal axis (y) via a second pivot joint, wherein a grabber or rotator, which is connected to the grabber and is adapted for enabling a controlled rotation of the grabber around the substantially vertical geometric axis (z); a plurality of sensors installed within an elastically deformable central area of the link member, wherein the plurality of sensors are suitable for detecting deformations of the link member which are generated due to the weight of a load held by the grabber hung on the arm of the crane, wherein said elastically deformable area together with said first and second eyes forms a rigidly interconnected stirrup, which is generally tubular and is weakened by an extensive internal passage which has either a circular or a polygonal cross-section, wherein the internal passage is symmetric with respect to said substantially vertical geometric axis (z), wherein said internal passage comprises two embedded elastically deformable lateral walls and extends along a substantially horizontal geometric axis (x′), which extends parallel to the geometric axis (x, y) of one of the first and second eyes; a measuring beam disposed within the interior of said internal passage approximately in the area of the longest distance between said lateral walls, wherein the measuring beam is rigidly connected to both lateral walls in a section that is elastically deformable and stable in view of buckling at least in a longitudinal direction (y′) extending perpendicularly to said longitudinal axis (x′) of the internal passage, wherein said measuring beam comprises at least one flat surface, which extends in a direction of said longitudinal axis (x′), and onto which the plurality of sensors are attached, wherein the plurality of sensors are electrically connected with each other and are suitable for measuring extensions or contractions of said measuring beam in the direction of its longitudinal axis (x′) resulting from elastic deformations of the central area due to varying distance between the lateral walls when the link member is exposed to stresses in a direction along said substantially vertical geometric axis (z).
2 . The load weighing link member according to claim 1 , wherein the central internal passage in the elastically deformable central area of the link member ( 1 ) is configured as a cylindrical through hole.
3 . The load weighing link member according to claim 2 , wherein the longitudinal axis (y′) of the measuring beam is arranged within a substantially horizontal plane of the cylindrical central passage in the central area of the link member.
4 . The load weighing link member according to claim 3 , wherein each of the lateral walls in the central area of the link member comprises a flat surface extending in a direction of said substantially vertical geometric axis (z), wherein the flat surfaces are substantially parallel.
5 . The load weighing link member according to claim 4 , further comprising a through hole is disposed in each of said lateral walls in the area of each of the said flat surfaces, wherein said through holes extend coaxially wherein the measuring beam is inserted through said through holes and is rigidly connected with each one of the lateral walls.
6 . The load weighing link member according to claim 5 , wherein the measuring beam has a generally cylindrical shape, while said flat surface has a rectangular cross-section.
7 . The load weighing link member according to claim 6 , wherein both terminal ends of said measuring beam are adjusted for inserting into said coaxial through holes, wherein the terminal ends are further adapted for establishing a rigid connection to each lateral wall of the elastically deformable central area of the link member.
8 . The load weighing link member according to claim 7 , further comprising two transverse recesses that are substantially semicircular in profile and disposed between said central area and each corresponding terminal end, wherein the two transverse recesses are symmetrical with regard to said longitudinal geometric axis (y′) and extend in the transverse direction with respect to said longitudinal geometric axis (y′) and are also perpendicular with respect to planes of the substantially flattened and weakened central area of the measuring beam.
9 . The load weighing link member according to claim 8 , wherein a first set of said plurality of sensors is configured for measuring extensions or contractions of said measuring beam in a direction of the longitudinal geometric axis (y′) thereof, wherein a second set of the plurality of sensors is configured for measuring extensions or contractions of said measuring beam in a direction along its transverse geometric axis (x′), wherein the first and second sets of said sensors are electrically connected to form a Wheatstone bridge of the measuring unit.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a United States national phase application of co-pending International Patent Application No. PCT/SI2022/000004, filed on 25 Jul. 2022, which claims the benefit of Slovenia Patent Application No. P-202100165 filed 1 Sep. 2021, both of which are hereby incorporated by reference in their entirety. BACKGROUND The present disclosure refers to a link member of a crane arm, e.g. of an arm on a mobile hydraulic crane with a telescopic arm, which is mountable on a motor vehicle, wherein the link member is suitable for weighing a load during transportation thereof by means of a grabber, which is attached to said crane arm and which is rotatable around a substantially vertical geometric axis in a controlled manner, together with the load. Pursuant to the International Patent Classification, the present disclosure belongs to transporting and working operations, namely to cranes, and specifically to technical features of load engaging elements or devices in connection with determining of the weight of the load, and should therefore belong to the IPC-Class B 66 C 13/16. The present disclosure refers to a link member, which is suitable for attaching to a grabber. This grabber is suitable for manipulating loads by means of a crane arm, wherein said grabber is attached to a crane arm and configured to freely rotate around each one of a set of perpendicular and substantially horizontal geometric axes. The grabber is also able to be rotated around a substantially vertical geometric axis along with the load. The present disclosure enables weighing of the load, when it is held by said grabber, which may be freely hanging on said crane arm in a static or in a dynamic state during transportation. The link member is suitable for performing a controlled rotation of the grabber together with the load around a substantially vertical geometric axis while performing a correct measurement despite inertial forces that occur during accelerating or decelerating of the load by rotating it around the vertical geometric axis. For the purpose of understanding and interpretation of the present disclosure, the expression “substantially vertical geometric axis” means a geometric axis, which extends through the link member and is perfectly vertical when the grabber is freely hanging with the load, although during the practical use said grabber may be temporarily pivoted at a certain angle from the vertical axis, and in particular whenever the grabber along with the load is swiveled around the horizontal axis. Thus, the term “substantially vertical geometric axis” should be understood as to refer to an axis, which is located within the horizontal plane when the link member is maintained in position by the free hanging grabber, but can generally also be deflected from said horizontal plane during practical use, as a consequence of swinging the grabber together with the load. A crane arm with a link member for operational accessory is disclosed in EP 1 889 808, wherein the rotating operational accessory, in particularly a grabber for gripping and transportation of timbers or other cylindrical solid objects, can be attached to the crane arm by means of said link member. A link member as such is also described in EP 2 931 646 B1 may comprise two pivot joints, which are along spaced apart from each other along the vertical axis. These joints may include a top pivot joint, which is arranged on the side of the crane arm, and a bottom pivot joint, which is arranged on the side of the rotation unit on the operational accessory, wherein said pivot joints may be configured in a Cardan joint, wherein both pivoting axles thereof extend perpendicular to each other, around which the link member can be pivoted relative to the crane arm and the rotating unit. Furthermore, the bottom pivot joint of the link member is configured for establishing a pivotal interconnection between the link member and the rotating unit, and therefore presents an eye with a through hole, which passes in a direction of said pivoting axis of the bottom pivot joint and is configured to receive a bolt, while the top pivot joint is arranged on the side of the crane arm and is configured for establishing interconnection therewith, wherein said top pivot joint is created as a fork comprising two arms, which are spaced apart from each other and are each furnished with a bore therethrough, such that a bolt is insertable through these bores, which may be used to establish a connection with the crane arm. Still further, a weighing apparatus for cranes is disclosed in CN 104 016 232 B, which comprises a carrying eye and a carrying hook, which are separated from each other in the vertical direction. The carrying eye is attached to the top attachment plate, while the hook is attached to the bottom attachment plate and the whole assembly is encased with a cover. Said carrying plates are connected through a sensor for measuring the extension r