NL2030293B1 - Rope operated mechanical grab - Google Patents

Rope operated mechanical grab Download PDF

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Publication number
NL2030293B1
NL2030293B1 NL2030293A NL2030293A NL2030293B1 NL 2030293 B1 NL2030293 B1 NL 2030293B1 NL 2030293 A NL2030293 A NL 2030293A NL 2030293 A NL2030293 A NL 2030293A NL 2030293 B1 NL2030293 B1 NL 2030293B1
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NL
Netherlands
Prior art keywords
grab
closing line
lever arm
cable
shells
Prior art date
Application number
NL2030293A
Other languages
Dutch (nl)
Inventor
Jan Willem Visser Peter
Original Assignee
Verstegen Grijpers B V
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Verstegen Grijpers B V filed Critical Verstegen Grijpers B V
Priority to NL2030293A priority Critical patent/NL2030293B1/en
Priority to PCT/EP2022/087775 priority patent/WO2023118584A1/en
Application granted granted Critical
Publication of NL2030293B1 publication Critical patent/NL2030293B1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C3/00—Load-engaging elements or devices attached to lifting or lowering gear of cranes or adapted for connection therewith and intended primarily for transmitting lifting forces to loose materials; Grabs
    • B66C3/12—Grabs actuated by two or more ropes

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Load-Engaging Elements For Cranes (AREA)

Abstract

The present invention relates to a rope operated mechanical grab, comprising a first lever arm with a first grab shell and a second lever arm with a second grab shell and a pivot connection between the lever arms. The first lever arm comprises a closing line attachment point at an intermediate section, between its opposed ends, and the second lever arm comprises a closing line guiding sheave at an intermediate section, between its opposed ends. The grab is configured to receive a closing line, which is configured to be attached to the closing line attachment point and configured to extend from the closing line attachment point, via the closing line guiding sheave, e.g. further extending upwards towards a crane from which the grab is configured to be suspended.

Description

P34843NLOO/TRE
Title: Rope operated mechanical grab
Field of the invention
The present invention relates to a rope operated mechanical grab for handling loads, in particular for handling bulk loads. The present invention further relates to a grab assembly and to a method for handling bulk loads.
State of the art
At present, various types of mechanical grabs are known. A first common type of mechanical grabs is the clamshell grab, which is characterized by a relatively low weight and high capacity and which is generally used to handle free-flowing bulk materials. The shells of these grabs are pushed downwards into the material by two arms when two pulley blocks are pulled together in a vertical way.
A second common type of mechanical grabs is the scissors grab, which operates in a different way with horizontal pulley blocks above a main hinge point between lever arms. The combination of the horizontal pulley blocks and the central hinge point results in a circular closing path of the shells.
As a third type, so-called trimming grabs are known, which comprise two arms, which are pivotally connected to a top block at the tops of the arms. The trimming grab comprises shells at the lower ends of the arms and comprises closing sheaves in the middle of the arms.
In an open position of the grabs, the shells are moved away from each other and the arms become aligned almost anti-parallel, i.e. almost 180°, with each other. In this open position, the closing sheaves of both arms are located away from each other. For closing the grab, closing lines are pulled in from the crane from which the grab is suspended. The closing line extends along closing sheaves of the opposed arms and via the top block. Upon closure, the closing sheaves on the arms are moved towards each other, to also move the grab shells at the lower ends of the arms towards each other.
A benefit of a trimming grab is that the grab shells travel in a substantially horizontal plane upon movement between an open and closed position, whereas other grabs will come up during closing. The flat horizontal closure of the trimming grab is beneficial to obtain a constant, i.e. flat scraping of bulk material upon filling the grab, whereas other grabs would have to dig into the bulk material to obtain a good filling.
In the known trimming grab, the closing line passes only along multiple closing line guiding sheaves. The passes will result in a relatively large closure force, i.e. the force at which the grab shells can be moved towards each other during closing of the grab.
On the other hand, this known trimming grab has the drawback that the closure length of the grab, i.e. the length of the closing line that needs to be drawn in by the crane for closing the grab, is relatively large, because the closing line is guided over multiple closing line guiding sheaves. This large closure length results in a relatively low closing speed of the grab, which reduces productivity of the grab during use.
Furthermore, the passage of the closing lines through the top block gives rise to internal stresses within the grab, because closure forces need to be transmitted internally between the closing line guiding sheaves and sheaves in the top block, thereby requiring stiffening of the arms, which increases weight and thus also reduces productivity.
Object of the invention
It is therefore an object of the invention to provide a mechanical grab that lacks one or more of the above-mentioned drawbacks, or at least to provide an alternative mechanical grab.
Detailed description
The object of the invention is achieved by the present invention, which provides, according to a first aspect, a rope operated mechanical grab, for example a four rope operated mechanical grab that is operated by a crane with two hoisting lines and two closing lines, for handling loads, in particular for handling bulk loads, the mechanical grab according to the invention comprising: - a first lever arm, comprising a first end and an opposed second end, wherein the grab comprises a first grab shell mounted at the first end of the first lever arm, - a second lever arm, comprising a first end and an opposed second end, wherein the grab comprises a second grab shell mounted at the first end of the second lever arm, - a direct pivot connection between the second end of the first lever arm and the second end of the second lever arm that is free of any sheaves, wherein the first lever arm comprises a closing line attachment point, wherein the second lever arm comprises an initial closing line guiding sheave, and wherein the grab is configured to receive a closing line, which is configured to be attached to the closing line attachment point and configured to extend from the closing line attachment point, via the initial closing line guiding sheave, directly towards a crane from which the grab is configured to be suspended.
The mechanical grab according the present invention thus comprises a first lever arm and a second lever arm, which are pivotally connected to each other at their second, e.g. upper ends. The pivotally interconnected lever arms together have a shape that mimics an A in a closed position of the grab. The pivot connection between the lever arms is a direct pivot connection, which means that the first lever arm and the second lever arm rotate with respect to each other about a common axis of rotation.
This pivoting configuration forms a first difference with the known grabs, since the known scissors grabs are pivotally connected at a central section of the arms and since the known trimming grabs are not directly connected to each other at the upper ends of the arms, but instead comprise a top block, to which each of the arms is pivotally connected.
Overall, the construction of the grab according to the present invention is thus less complex than that of existing grabs, thereby allowing the weight of the grab to be less, thus giving rise to an improved productivity. Hence, a crane can only handle loads up to a certain threshold load, which implies that a larger amount of bulk material can be grabbed when the empty weight of the grab is reduced.
Each of the lever arms of the present grab comprises a grab shell, wherein a first grab shell is mounted at a first, e.g. lower end of the first lever arm and wherein a second grab shell is mounted at a first, e.g. lower end of the second lever arm. In the closed position of the grab, the first grab shell and the second grab shell contact each other to define an interior of the grab in between them. In an open position of the grab, the lever arms of the grab have moved away from each other and the grab shells are spaced at a distance from each other. In this opened position of the grab, the lever arms preferably become aligned almost anti- parallel, i.e. aligned at almost 180° from each other, both substantially extending in a horizontal direction.
Since the pivot connection is spaced from each of the grab shells at a distance equal to about the length of the lever arms, is the resulting distance between the grab shells in the open position of the grab, i.e. with the lever arms aligned almost anti-parallel, about two times the length of the arms. This distance between the grab shells, which defines the travel path of the grab shells during closing of the grab, is representative for the amount of bulk material that can be scraped into the grab shells and is thus similar as in the present trimming grab.
During use of the grab, a closing line is connected to the grab for effecting a movement from the open position of the grab to its closed position, or vice versa, by a crane to which the closing line is attached and from which the grab is suspended, for example by means of one or two hoisting lines. The closing line is configured to be connected to the closing line attachment point at the first lever arm and is guided towards the crane via the initial closing line guiding sheave at the second lever arm.
With the closing line attachment point and the initial closing line guiding sheave provided on opposed lever arms of the grab, the closing line will horizontally cross between the lever arms when installed on the grab. After extending horizontally towards a closing line guiding sheave, e.g. towards the initial closing line guiding sheave, the closing line may directly extend towards the crane in a substantially upward direction, without passing along further deflection sheaves of the grab, in order to minimize contact between sheaves of the grab, thus to minimize wear of the sheaves and the closing line.
The initial closing line guiding sheave may be the sole closing line guiding sheave of the grab, so that the closing line departs from the grab after having passed the initial closing line guiding sheave. Alternatively, however, the grab may comprise further closing line guiding sheaves along which the closing line is to be passed before departing to the crane.
In existing grabs, which comprise a top block, the closing line is typically guided towards the centre of the grab, in between the respective pivot connections of the top block with each of the lever arms, to depart from the grab at the top block in the upward direction. This guiding requires additional sheaves in the top block, which solely serve the purpose of guiding the cable and which have no contribution in increasing the closure force of the grab, thus only result in additional wear and friction. According to the present invention, no top block is present and the cables depart from the grab at the closing line guiding sheaves at the lever arms, thereby reducing the wear and friction that is present in existing grabs.
Furthermore, the sheaves in the top block of the existing trimming grabs introduce a reversal in the bending direction of the closing line. The guiding along the closure sheaves for example only concerns bending in a clockwise direction, whereas the guiding along the sheaves in the top block of the existing trimming grab concerns bending in the counter clockwise direction. This reversal of the bending of the closing lines further deteriorates the wear of the closing lines used in existing trimming grabs. Compared to the existing trimming grabs, the absence of a top block and corresponding sheaves in the present grab may lack such bending reversals, thereby further reducing wear and friction of the closing lines.
The absence of a top block and closing line guiding sheaves at the pivot connection thus reduces wear of the closing line and correspondingly reduces friction, enabling more efficient operation of the grab according to the present invention.
Furthermore, fewer internal stresses occur in the arms of the grab, because the closing lines do not extend along the lever arms, as they would when they had to extend towards a top block. The departure of the closing line at the closing line guiding sheave at the lever arm provides that the pivot connection between the arms only serves the purpose of guiding rotations between the arms, lacking transmission of forces that would otherwise result from the guiding of the closing lines. This allows the present grab to be constructed lighter, as it is subjected to smaller stresses, thereby allowing an increase in productivity.
Finally, the omission of a top block and lighter construction of the lever arms may lower the centre of gravity of the grab, resulting in more stable positioning on sloped surfaces, fur example on piles of bulk material, thereby reducing the risk of tumbling of the grab.
In an embodiment of the grab, the first lever arm has an intermediate section, in between its first end and its second end, the second lever arm has an intermediate section, in between its first end and its second end, the closing line attachment point is provided at the intermediate section of the first lever arm, and the initial closing line guiding sheave is 5 provided at the intermediate section of the second lever arm.
In between their first, e.g. upper ends and their second, e.g. lower ends, the lever arms comprise respective intermediate sections, e.g. centrally in between the first and second ends, preferably in the middle of them, and thus centrally between the pivot connection and the grab shells. The closing line attachment point is mounted to the first lever arm at the intermediate section thereof, thus in between the pivot connection and the first grab shell. The initial closing line guiding sheave is mounted to the second lever arm at the intermediate section thereof, thus in between the pivot connection and the second grab shell.
According to this embodiment, the closing line guiding sheave and the closing line attachment point are provided at respective lever arms centrally in between the grab shell and the pivot connection. This placement provides for a useful balance between closure force and the closure length, i.e. reaching a desired closure force whilst having an acceptable closure length.
In a further embodiment of the grab, the first lever arm comprises a successive closing line guiding sheave at its intermediate section, and the closing line is configured to extend from the closing line attachment point, via the initial closing line guiding sheave and via the successive closing line guiding sheave, directly towards the crane from which the grab is configured to be suspended.
According to this embodiment, the grab may contain exactly two closing line guiding sheaves for the closing line, namely the initial closing line guiding sheave and the successive closing line guiding sheave. In fact, the closing line is configured to span between the lever arms for two passes: once from the successive closing line guiding sheave to the initial closing line guiding sheave and once from the initial closing line guiding sheave to the closing line attachment paint, in order to increase the closure force compared to when the closing line were to make a single pass between the lever arms.
This grab preferably contains no further guiding sheaves for this closing line, to avoid that the closure length will become too large and that the closing speed of the grab will become too low to be practically feasible.
The closing line attachment point is provided at the first lever arm, the initial closing line guiding sheave is provided at the second lever arm and the successive closing line guiding sheave is provided at the first lever arm again. The closing line is thus configured to span from the intermediate section of the first lever arm to the intermediate section of the second lever arm and back to the intermediate section of the first lever arm before extending further upward, e.g. without passing along further closing line guiding sheaves of the grab, towards the crane from which the grab is suspended.
In an embodiment of the grab, the second lever arm comprises a second closing line attachment point at its intermediate section, the first lever arm comprises a second initial closing line guiding sheave at its intermediate section, and the grab is configured to receive a second closing line, which is configured to be attached to the second closing line attachment point and configured to extend from the second closing line attachment point, via the second initial closing line guiding sheave, directly towards the crane.
According to this embodiment, the grab is adapted to receive a second closing line from the crane from which it is suspended. Such a second closing line typically acts parallel to the closing line, i.e. the first closing line, to double the closure force of the grab, without increasing the closure length. Such a second closing line may either be attached to a second closing winch of the crane or may be connected to the first closing line at a closing line coupling element. Such a coupling element may be configured to receive the first closing line and the second closing line, i.e. after they have departed from the grab, and may connect the closing lines to each other so that only a single, e.g. common closing line extends towards the crane.
The second closing line extends through the grab in a direction opposite to the first closing line and may essentially be mirror symmetric with respect to the first closing line.
Hence, the distal end of the second closing line is configured to be connected to the second closing line connection point on the second lever arm, where the first closing line is connected to the first lever arm. Similarly, the second closing line passes from the second lever arm to the first lever arm to be guided along the second initial closing line guiding sheave, before being guided upwards to the crane from which the grab is suspended.
The symmetric closing lines, i.e. the second closing line extending in the grab in a direction opposite to the first closing line, have the advantage that the closure force can be spread symmetrically between the lever arms, and therefore also between the grab shells, resulting in a more uniform closure movement. Furthermore, as indicated above, the presence of two closing lines provides that the closure force can be two times higher than with a single closing line or, alternatively, that the tensile force in the two closing lines can be half the tensile farce that would occur in a single closing line, whilst still obtaining the same closure force between the grab shells.
In a further embodiment of the grab, the second lever arm comprises a second successive closing line guiding sheave at its intermediate section, and the second closing line is configured to extend from the second closing line attachment point, via the second initial closing line guiding sheave and via the secondary successive line guiding sheave, directly towards the crane from which the grab is configured to be suspended.
According to this embodiment, the grab may also contain exactly two closing line guiding sheaves for the second closing line, namely the second initial closing line guiding sheave and the second successive closing line guiding sheave. This grab preferably contains no further guiding sheaves for the second closing line either, to avoid that the closure length will become too large and that the closing speed of the grab will become too low to be practically feasible.
The second closing line attachment point is provided at the second lever arm, the second initial closing line guiding sheave is provided at the first lever arm and the second successive closing line guiding sheave is provided at the second lever arm again. The second closing line is thus configured to span from the intermediate section of the second lever arm to the intermediate section of the first lever arm and back to the intermediate section of the second lever arm before extending further upward, e.g. without passing along further closing line guiding sheaves of the grab, towards the crane from which the grab is suspended.
In an embodiment, the grab further comprises: - a lifting frame, with which the grab is configured to be suspended from the crane, e.g. from at least one hoisting line of the crane, - at least one first lifting line, which extends between the lifting frame and one of the first grab shell and the first lever arm, and - at least one second lifting line, which extends between the lifting frame and one of the second grab shell and the second lever arm.
The grab according to this embodiment is configured to be suspended from the crane by means of the lifting frame, which is adapted to be suspended from the hoisting line of the crane, or a plurality of hoisting lines, for example two hoisting lines in the case of a four rope operated mechanical grab. The lifting frame is typically suspended above the grab, i.e. the grab shells and the lever arms, and allows the hoisting line from the crane above it to extend in a substantially vertical direction, whereas the lifting lines towards the lever arms or the grab shells typically not extend entirely vertical, but also have a component extending sideways, because the lever arms and the grab shells are typically wider than the lifting frame.
The at least one first lifting line, preferably two first lifting lines, is connected to the lifting frame and to the first lever arm or the first grab shell. With two first lifting lines, a respective first lifting line may extend to each of the sides of the first lever arm or the first grab shell, to support the first grab shell in a stable manner. Similarly, the at least one second lifting line, preferably two second lifting lines, is connected to the lifting frame and to the second lever arm or the second grab shell. With two second lifting lines, a respective second lifting line may extend to each of the sides of the second lever arm or the second grab shell, to support the second grab shell in a stable manner. The first and second lifting lines preferably comprise lifting chains, which enable reliable support of the grab, without having substantial wear during their lifespan.
The lifting lines may extend from the lifting frame to either the lever arms or to the grab shells, depending on the construction of the grab. In case the grab shells are mounted fixedly to the lever arms, for example by means of a welded connection, as in conventional grabs, the both options for the lifting lines are possible.
However, the present invention also provides a grab in which the grab shells are releasably connected to the first ends of the lever arms. In those embodiments, the lifting lines are preferably connected to the lever arms, for example to the first ends of the lever arms, to ensure that the grab can also be suspended from the lifting lines when the grab shells are disconnected from the lever arms.
In a further embodiment of the grab, the first grab shell and the second grab shell each comprise at least one respective lifting eye, the at least one first lifting line is connected to the at least one lifting eye of the first grab shell, and the at least one second lifting line is connected to the at least one lifting eye of the second grab shell.
According to this embodiment, the lifting lines are attached directly to the grab shells via the lifting eyes. This embodiment may be beneficial where the grab shells are mounted fixedly to the lever arms, for example to obtain a high degree of stability of the grab.
In a further embodiment, grab comprises a closing line coupling element, configured to receive the first closing line and the second closing line and configured to connect the closing lines to each other. The closing line coupling element is thus configured to recombine the closing lines so that only a single, e.g. common closing line eventually extends towards the crane.
In an embodiment of the grab, the direct pivot connection comprises a pivot pin, extending at least partially through one or more bearing seats in the first lever arm and through one or more bearing seats in the second lever arm.
Such a direct connection can be established between the lever arms, without requiring any additional components, other than the pivot pin, but at least without a top block that is present in the trimming grabs known from the prior art.
The omission of a top block has several advantages mentioned above. Furthermore, the absence of such a top block, and the provision of a direct pivot connection, takes away a degree of freedom of the grab. Accordingly, the direct connection between the lever arms provides that the grab can stand upright in its open position more stable on a ground plane, when not in use, without having the risk that either one of the lever arms tumbles down.
In an embodiment of the grab, the grab shells are mounted to the lever arms by means of a releasable connection. The grab according to this embodiment differs from the known grabs, such as trimming grabs and scissor grabs, which generally comprise grab shells that are fixedly attached to the lever arms. The releasable connection allows exchange of grab shells, so that the type of grab shells can be adapted to the specific type of bulk material for which the grab is to be used, without requiring replacement of the entire grab.
In case it is desired to use the grab for handling lightweight bulk materials, i.e. bulk materials with a low density, like fertilizer or grain, grab shells with a large volume may be installed, whereas small grab shells may be installed when the grab were to be used to handle heavy materials like pig iron or iron ore.
Furthermore, the releasable connection allows for replacement of grab shells, for example in case the grab shells have worn out. Hence, the grab shells suffer from wear during the grabbing of bulk material, having an influence on their lifespan, whereas other components, like the lever arms, do not suffer from such wear, thereby having a longer lifespan.
In a further embodiment of the grab, the first lever arm and the second lever arm each comprise at least one respective lifting eye at their first ends, the at least one first lifting line is connected to the at least one lifting eye of the first lever arm, and the at least one second lifting line is connected to the at least one lifting eye of the second lever arm.
In this embodiment, the lifting lines are attached directly to the lever arms via the lifting eyes. This embodiment may be beneficial where the grab shells are mounted to the lever arms releasably, for example to ensure that the grab can also be suspended from the lifting lines when the grab shells are disconnected from the lever arms.
In an alternative or additional embodiment of the grab, the releasable connection between the lever arms and the grab shell comprises a pen connection and/or a bolted connection.
Such a pen connection or bolted connected maybe released relatively easily to enable rapid exchange of grab shells, whilst still offering a reliable support for the grab shells.
In an embodiment of the grab, the grab shells each comprise a bent bottom, a respective side wall on opposed sides of the bent bottom and stiffening ribs in between the side walls and extending parallel to the side walls.
The bent bottoms of the grab shells together define the interior of the grab, configured to hold the bulk material in the closed position of the grab. This construction of the grab shells enables lightweight grab shells, whilst still offering sufficient strength to be able to grab all sorts of bulk materials with the grabs shells, without damaging the grab shells.
In particular, the stiffening ribs of each of the grab shells may be flush with the respective lever arm to which the grab shell is attached. The lever arms may for example be integral with the stiffening ribs to allow for an optimal rigidity of the grab and to optimize the transfer of forces between the lever arms and the grab shells, in particular during the closing of the grab, during which relatively large forces may act onto the lever arms and the grab shells.
In a further embodiment, each of the grab shells further comprises at least one cover, which each extends between a side wall and a stiffening rib, to at least partially close off an interior of the respective grab shell.
In particular, the first grab shell may comprise a first cover between a first side wall and a first stiffening rib and a second cover between a second side wall and a second stiffening rib. Furthermore, the second grab shell may comprise a first cover between a first side wall and a first stiffening rib and a second cover between a second side wall and a second stiffening rib.
The covers between the side walls and the stiffening ribs may contribute to the stiffness of the grab shells, which may in particular be beneficial where the grab shells are releasable from the lever arms. In the absence of a connection with the lever arms, the grab shells would otherwise be relatively weak and easy to deform, whereas the covers may contribute in preventing deformations of the grab shells.
The presence of covers in the grab according to the present embodiment also provides a further difference in view of the known grabs, which lack such covers. Moreover, the absence of covers is essential in trimming grabs, because trimming grabs rely on spilling of bulk material over the edges of the bottom, to prevent overloading of the grab. Hence, such trimming grabs are used to grab heavy materials and rely on scraping over the top surface of the bulk material to become filled. In case covers were to be provided on such trimming grabs, the bulk material could not be spilled, resulting in the risk that the grab could not be closed due to a too large amount of bulk material being present in the grab shells. The same applies for scissors grabs, which have sheaves moving into grab shells of the opposed lever arm in an opened position. In case covers would be provided in such scissors grabs, the grabs could not be opened fully, because the sheaves would collide with the covers.
In a further embodiment of the grab, each of the covers further extends between the side walls and over the stiffening ribs to substantially close off the interior of the respective grab shell. According to this embodiment, the covers may cover the entire grab shells between their respective side walls. The covers in the present embodiment can be used to cover the top sides of each of the grab shells, to be able to substantially close off the interior of the grab in its closed position. In case the grab is used to handle relatively fine bulk materials, possibly even being poisonous in large quantities, the covers prevent the bulk material from escaping from the grab, for example under influence of wind, which provides for more environmentally-friendly handling of bulk materials.
In an embodiment of the grab, the first lever arm and the second lever arm are rotatable relative to each other about the direct pivot connection to move the grab between a fully closed position and a fully opened position of the grab, and the lever arms are, upon movement between the fully closed position and the fully opened position, configured to rotate over an opening angle in a range between 100° and 170°, preferably in a range between 120° and 150°, for example over 150°.
The grab according to this embodiment enables a relatively large opening angle, and thus a relatively large spread between the grab shells in the fully opened position. The opening angle, however, will remain lower than 170°. In this way, it may be prevented that the closing cable, which spans between the lever arms, will contact the bulk material that is to be grabbed.
Furthermore, a maximum opening angle of less than 170° ensures that the closure force exerted by the grab is already sufficient at the onset of closing. An opening angle larger than 170° would yield the risk that the grab cannot be closed by pulling the closing line.
In an embodiment of the grab, the first grab shell and the second grab shell each comprise a planar cutting edge, wherein, in the fully closed position of the grab, the planar cutting edges are aligned non-parallel relative to each other, and wherein, in the fully opened position of the grab, the planar cutting edges are aligned in a substantially vertical plane.
In existing trimming grabs, the grab shells have cutting edges aligned horizontally and parallel to each other in the closed position of the grab. This trimming grab will not be opened as much as 180°, which implies that the cutting edges of these trimming grabs will be set at an angle relative to the vertical direction in the fully opened position of the grab.
The present embodiment of the grab differs from the known grabs in that, in the closed position of the grab, the grab shells contact each other with the cutting edges, which define a discrete angle in between them and which are aligned non-parallel. In the fully opened position, the planar cutting edges are spaced apart, but are aligned parallel to each other and parallel to a vertical direction. Upon lowering the opened grab onto the bulk material that is to be grabbed, the planar cutting edges will encounter less resistance upon penetrating the bulk material. As a result, the grab will be lowered further into the bulk material under influence of its own weight compared to an existing grab of similar weight but with non-vertical cutting edges.
In a further embodiment of the grab, a cutting edge angle is defined between the cutting edge of the first grab shell and the cutting edge of the second grab shell in the fully closed position of the grab, and the cutting edge angle is defined in a range between 100° and 170°, preferably in a range between 120° and 150°, for example at 135°.
As a result of the cutting edge angle in this range, the planar cutting edges may be aligned vertically in the fully opened position of the grab, in order to obtain the beneficial penetration effect of the grab that is described above.
According to a second aspect, the present invention provides a rope operated mechanical grab, comprising: - a first lever arm, comprising a first grab shell mounted at an end thereof, - a second lever arm, comprising a second grab shell mounted at an end thereof, - a pivot connection between the first lever arm and the second lever arm, wherein the first lever arm comprises a closing line attachment point, wherein the second lever arm comprises an initial closing line guiding sheave, and wherein the grab is configured to receive a closing line, which is configured to be attached to the closing line attachment point and configured to extend from the closing line attachment point, via the initial closing line guiding sheave towards a crane from which the grab is configured to be suspended, wherein the first grab shell and the second grab shell each comprise a planar cutting edge, wherein, in a fully closed position of the grab, the planar cutting edges are aligned non- parallel relative to each other, and wherein, in a fully opened position of the grab, the planar cutting edges are aligned in a substantially vertical plane.
The grab according to the second aspect of the invention differs from the known grabs in that, in the closed position of the grab, the grab shells contact each other with the cutting edges, which define a discrete angle in between them and which are aligned non-parallel. In the fully opened position, the planar cutting edges are spaced apart, but are aligned parallel to each other and parallel to a vertical direction. Upon lowering the opened grab onto the bulk material that is to be grabbed, the planar cutting edges will encounter less resistance upon penetrating the bulk material. As a result, the grab will be lowered further into the bulk material under influence of its own weight compared to an existing grab of similar weight but with non-vertical cutting edges.
In an embodiment of the grab according to the second aspect of the invention, a cutting edge angle is defined between the cutting edge of the first grab shell and the cutting edge of the second grab shell in the fully closed position of the grab, and the cutting edge angle is defined in a range between 100° and 170°, preferably in a range between 120° and 150°, for example at 135°.
As a result of the cutting edge angle in this range, the planar cutting edges may be aligned vertically in the fully opened position of the grab, in order to obtain the beneficial penetration effect of the grab that is described above.
The grab according to the second aspect of the invention may be embodied with details as described herein with reference to the first aspect of the invention, including one or more of the optional and/or preferred details thereof, e.g. as stated in the appended claimset.
According to a third aspect, the present invention provides a rope operated mechanical grab, comprising: - a first lever arm, comprising a first grab shell mounted at an end thereof, - a second lever arm, comprising a second grab shell mounted at an end thereof, - a pivot connection between the first lever arm and the second lever arm, wherein the first lever arm comprises a closing line attachment point, wherein the second lever arm comprises an initial closing line guiding sheave, and wherein the grab is configured to receive a closing line, which is configured to be attached to the closing line attachment point and configured to extend from the closing line attachment point, via the initial closing line guiding sheave towards a crane from which the grab is configured to be suspended, wherein the grab shells are mounted to the lever arms by means of a releasable connection.
The grab according to the third aspect of the invention differs from the known grabs, such as trimming grabs and scissor grabs, which generally comprise grab shells that are fixedly attached to the lever arms. The releasable connection allows exchange of grab shells, so that the type of grab shells can be adapted to the specific type of bulk material for which the grab is to be used, without requiring replacement of the entire grab.
In case it is desired to use the grab for handling lightweight bulk materials, i.e. bulk materials with a low density, like fertilizer or grain, grab shells with a large volume may be installed, whereas small grab shells may be installed when the grab were to be used to handle heavy materials like pig iron or iron ore.
Furthermore, the releasable connection allows for replacement of grab shells, for example in case the grab shells have worn out. Hence, the grab shells suffer from wear during the grabbing of bulk material, having an influence on their lifespan, whereas other components, like the lever arms, do not suffer from such wear, thereby having a longer lifespan.
In an embodiment of the grab according to the third aspect of the invention, the releasable connection between the lever arms and the grab shell comprises a pen connection and/or a bolted connection. Such a pen connection or bolted connected maybe released relatively easily to enable rapid exchange of grab shells, whilst still offering a reliable support for the grab shells.
The grab according to the third aspect of the invention may be embodied with details as described herein with reference to the first aspect and/or second aspect of the invention, including one or more of the optional and/or preferred details thereof, e.g. as stated in the appended claimset.
The present invention further provides a grab assembly for handling loads, in particular for handling bulk loads, comprising: - the rope operated mechanical grab as disclosed herein, preferably as recited in the claims, - at least one closing line, configured to bring the grab from an opened position, e.g. a position in which the grab shells are spaced at a distance from each other, into a closed position, e.g. a position in which the grab shells contact each other, wherein the closing line comprises a proximal end that is adapted to be connected to a crane, in particular to a closing winch of the crane, and an opposed distal end that is attached to the closing line attachment point of the first lever arm, and wherein the closing line is, from its distal end, guided towards the crane directly via the initial closing line guiding sheave on the second lever arm.
For illustrating the benefits of the grab assembly according to the present invention over existing grab assemblies, reference is made to the benefits and advantages mentioned above in view of the mechanical grab according to the present invention, or embodiments thereof as disclosed herein.
The closing line in the grab assembly is connected to the grab for effecting a movement from the open position of the grab to its closed position, or vice versa, by a crane to which the closing line is attached and from which the grab is suspended, for example by means of one or two hoisting lines. The closing line is connected to the closing line attachment point at the first lever arm and is guided towards the crane via the initial closing line guiding sheave at the second lever arm.
The initial closing line guiding sheave may be the sole closing line guiding sheave of the grab, so that the closing line departs from the grab after having passed the initial closing line guiding sheave. Alternatively, however, the grab may comprise further closing line guiding sheaves along which the closing line is to be passed before departing to the crane.
With the closing line attachment point and the initial closing line guiding sheave provided on opposed lever arms of the grab, the closing line horizontally crosses between the lever arms when installed on the grab. After extending horizontally towards a closing line guiding sheave, e.g. towards the initial closing line guiding sheave, the closing line may directly extend towards the crane in a substantially upward direction, without passing along further deflection sheaves of the grab, in order to minimize contact between sheaves of the grab, thus to minimize wear of the sheaves and the closing line.
In an embodiment of the grab assembly, the closing line is, from its distal end, guided towards the crane directly via the initial closing line guiding sheave on the second lever arm and via the successive closing line guiding sheave on the first lever arm.
According to this embodiment, the grab may contain exactly two closing line guiding sheaves for the closing line, namely the initial closing line guiding sheave and the successive closing line guiding sheave. This grab preferably contains no further guiding sheaves for the closing line, to avoid that the closure length will become too large and that the closing speed of the grab will become too low to be practically feasible.
The closing line attachment point is provided at the first lever arm, the initial closing line guiding sheave is provided at the second lever arm and the successive closing line guiding sheave is provided at the first lever arm again. The closing line thus spans from the intermediate section of the first lever arm to the intermediate section of the second lever arm and back to the intermediate section of the first lever arm before extending further upward, e.g. without passing along further closing line guiding sheaves of the grab, towards the crane from which the grab is suspended.
In an embodiment, the grab assembly further comprises a second closing line, comprising a proximal end that is adapted to be attached to the crane, in particular to the closing winch of the crane, wherein a distal end of the second closing line is attached to the second closing line attachment point of the second lever arm, and wherein the second closing line is, from its distal end, guided towards the crane directly via the second initial closing line guiding sheave on the first lever arm.
According to this embodiment, the grab receives a second closing line from the crane from which it is suspended. Such a second closing line typically acts parallel to the closing line, e.g. the first closing line, to double the closure force of the grab, without in increasing the closure length. Such a second closing line may either be attached to a second closing winch of the crane or may be connected to the first closing line after having departed from the grab, so that only a single, e.g. common closing line extends towards the crane.
The second closing line extends through the grab in a direction opposite to the first closing line and may essentially be mirror symmetric with respect to the first closing line.
Hence, the distal end of the second closing line is configured to be connected to the second closing line connection point on the second lever arm, where the first closing line is connected to the first lever arm. Similarly, the second closing line passes from the second lever arm to the first lever arm to be guided along the second initial closing line guiding sheave, before being guided upwards to the crane from which the grab is suspended.
The symmetric closing lines, i.e. the second closing line extending in the grab in a direction opposite to the first closing line, have the advantage that the closure force can be spread symmetrically between the lever arms, and therefore also between the grab shells, resulting in a more uniform closure movement. Furthermore, as indicated above, the presence of two closing lines provides that the closure force can be two times higher than with a single closing line or, alternatively, that the tensile force in the two closing lines can be half the tensile force that would occur in a single closing line, whilst still obtaining the same closure force between the grab shells.
In a further embodiment of the grab assembly, the second closing line is, from its distal end, guided towards the crane directly via the second initial closing line guiding sheave on the first lever arm and via the second successive closing line guiding sheave on the second lever arm.
According to this embodiment, the grab may also contain exactly two closing line guiding sheaves for the second closing line, namely the second initial closing line guiding sheave and the second successive closing line guiding sheave. This grab preferably contains no further guiding sheaves for the second closing line either, to avoid that the closure length will become too large and that the closing speed of the grab will become too low to be practically feasible.
The second closing line attachment point is provided at the second lever arm, the second initial closing line guiding sheave is provided at the first lever arm and the second successive closing line guiding sheave is provided at the second lever arm again. The second closing line thus spans from the intermediate section of the second lever arm to the intermediate section of the first lever arm and back to the intermediate section of the second lever arm before extending further upward, e.g. without passing along further closing line guiding sheaves of the grab, towards the crane from which the grab is suspended.
In an embodiment, the grab assembly further comprises at least one hoisting line, configured to suspend the grab from the crane, wherein the at least one hoisting line comprises a proximal end that is adapted to be connected to the crane, in particular to a hoisting winch of the crane, and an opposed distal end that is attached to the grab, and wherein the distal end of the at least one hoisting line is preferably indirectly connected to the grab shells, for example via the lifting frame, via the at least one first lifting line and via the at least one second lifting line.
The present invention also provides a method of handling bulk loads by means of a grab assembly as disclosed herein, e.g. comprising the grab as disclosed herein, comprising the steps of: - moving the grab towards a loading location in its opened position; - pulling at least one closing line, i.e. pulling the first closing line and the second closing line, if present, to bring the grab into its closed position, in order to grab bulk material within the grab shells; - moving the grab towards a discharge location; and - releasing the at least one closing line, i.e. releasing the first closing line and the second closing line, if present, to bring the grab into its opened position, in order to discharge the bulk material from the grab shells.
Brief description of drawings
Further characteristics of the invention will be explained below, with reference to embodiments, which are displayed in the appended drawings, in which:
Figure 1 schematically depicts an embodiment of the grab according to the present invention in a fully opened position,
Figure 2 depicts the grab of figure 1 in a closed position,
Figure 3 depicts a frontal view on an embodiment of the grab assembly according to the present invention,
Figure 4 schematically depicts a detailed view on the grab of figure 2, showing the planar cutting edges,
Figure 5 depicts a side view on the grab assembly of figure 3, and
Figure 6 depicts a cross-sectional view along plane E — E in figure 5.
Throughout the figures, the same reference numerals are used to refer to corresponding components or to components that have a corresponding function.
Detailed description of embodiments
Figures 1 and 2 depicts an embodiment of the grab according to the present invention, to which is referred with reference numeral 1. In figure 1, the grab 1 is shown in its fully opened position and in figure 2, the grab 1 is shown in its closed position.
The grab 1 is a four rope operated mechanical grab 1, which is configured to be operated by a crane by two closing lines 101 and two hoisting lines 102, as is shown in figures 3 — 6. The grab 1 is intended to handle bulk loads like bauxite, pig iron or stones.
The grab 1 comprises a first lever arm 11 and a second lever arm 21, which each comprise a first end and an opposed second end. The grab 1 comprises a first grab shell 12 mounted at the first end of the first lever arm 11 and a second grab shell 22 mounted at the first end of the second lever arm 21.
In the fully opened position of the grab 1, as shown in figure 1, the lever arms 11, 21 of the grab 1 have moved away from each other and the grab shells 12, 22 are spaced at a distance from each other. In the closed position of the grab 1, as shown in figure 2, the first grab shell 21 and the second grab shell 22 contact each other to define an interior 2 of the grab 1 in between them. In the closed position, the interconnected lever arms 11, 21 together have a shape that mimics an A.
The grab 1 comprises a direct pivot connection 31 between the second end of the first lever arm 11 and the second end of the second lever arm 21. The pivot connection 31 comprises a pivot pin, extending through bearing seats in the first lever arm 11 and through bearing seats in the second lever arm 21. The pivot connection 31 is free of any sheaves and does, opposed to existing trimming grabs, not comprise a top block.
The grab shells 12, 22 are mounted to the lever arms 11, 21 by means of a bolted releasable connection 32. The releasable connection 32 allows exchange of grab shells 12, 22, so that the type of grab shells 12, 22 can be adapted to the specific type of bulk material for which the grab 1 is to be used, i.e. using the same lever arms 11, 21 without requiring replacement of the entire grab 1.
It is shown best in figure 2 that the grab shells 12, 22 each comprise a respective bent bottom 13, 23 and respective side walls 14, 24 on opposed sides of the bent bottom 13, 23. In particular, each of the grab shells 12, 22 comprises a frontal side wall 14, 24 and a rear side wall 14’, 24’. The bent bottoms 13, 23 and side walls 14, 24 of the grab shells 11, 21 together define the interior 2 of the grab 1, configured to hold the bulk material in the closed position of the grab 1.
The grab shells 12, 22 further comprise stiffening ribs 15, 25 in between the side walls 14, 24 and extending parallel to the side walls 14, 24. The stiffening ribs 15, 25 of each of the grab shells 12, 22 are substantially flush with the respective lever arm 11, 21 to which the grab shell 12, 22 is attached. In other embodiments of the grab, without the releasable connection between the lever arms and the grab shells, the lever arms may be integral with the stiffening ribs to allow for an optimal rigidity of the grab and to optimize the transfer of forces between the lever arms and the grab shells, in particular during the closing of the grab.
Each of the grab shells 12, 22 further comprises two covers 16, 26, which each extend between a side wall 14, 24 and a stiffening rib 15, 25, to at least partially close off an interior of the respective grab shell 12, 22. In particular, the first grab shell 12 comprises a first cover 16 between a first, i.e. the frontal side wall 14 and a first stiffening rib 15, and a second cover 16’ between a second, i.e. the rear side wall 14’ and a second stiffening rib 15’. Furthermore, the second grab shell 22 comprises a first cover 26 between a first, i.e. the frontal side wall 24 and a first stiffening rib 25 and a second cover 26’ between a second, i.e. the rear side wall 24’ and a second stiffening rib 25’. The covers 16, 26 between the side walls 14, 24 and the stiffening ribs 15, 25 contribute to the stiffness of the grab shells 12, 22, which is beneficial in the present embodiment, with the grab shells 12, 22 being releasable from the lever arms 11, 21.
In other embodiments, covers may be provided to extend between the side walls and over the stiffening ribs to substantially close off the interior of the respective grab shell. In such embodiments, the covers cover the entire grab shells between their respective side walls.
In figure 3, an embodiment of the grab assembly according to the present invention is shown, to which is referred with reference numeral 100. The grab assembly 100 comprises the grab 1, of which the second lever arm 21 comprises a closing line attachment point 33 and of which the first lever arm 11 comprises an initial closing line guiding sheave 34. In particular, the closing line attachment point 33 is provided at an intermediate section of the second lever arm 21, i.e. in between the second lever arm's 21 first end and second end.
Furthermore, the initial closing line guiding sheave 34 is provided at an intermediate section of the first lever arm 11, i.e. in between the first lever arm’s 11 first end and second end.
The grab assembly 100 comprises a closing line 101, configured to bring the grab 1 from the opened position into the closed position and vice versa. The closing line 101 comprises a proximal end that is adapted to be connected to a crane and an opposed distal end that is attached to the closing line attachment point 33. From its distal end, the closing line 101 is guided towards the crane via the initial closing line guiding sheave 24.
The grab 1 comprises a successive closing line guiding sheave 35, which is provided on the second lever arm 21, along which the closing line 101 is passed before departing to the crane. The grab 1 thus contains exactly two closing line guiding sheaves 34, 35 for the closing line 101, namely the initial closing line guiding sheave 34 and the successive closing line guiding sheave 35. This grab 1 contains no further guiding sheaves for the closing line 101, so that it is avoided that the closure length will become too large and that the closing speed of the grab 1 will become too low to be practically feasible.
The closing line 101 thereby spans from the intermediate section of the second lever arm 21 to the intermediate section of the first lever arm 11 and back to the intermediate section of the second lever arm 21 before extending further upward, e.g. without passing along further closing line guiding sheaves of the grab 1, towards the crane from which the grab 1 is suspended.
In other embodiments, the grab assembly 100 could comprises a second closing line 107’. The second closing line 107’ is displayed in figure 3 in relation to the grab 1 in its fully opened position, whereas the first closing line 101 is displayed in figure 3 in relation to the grab 1 in its closed position.
The second closing line 101° acts parallel to the first closing line 101, to double the closure force of the grab 1, without in increasing the closure length. The second closing line 101" extends through the grab 1 in a direction opposite to the first closing line 101 and is essentially mirror symmetric with respect to the first closing line 101. The symmetric closing lines 101, 107’, i.e. the second closing line 101’ extending in the grab 1 in a direction opposite to the first closing line 101, have the advantage that the closure force can be spread symmetrically between the lever arms 11, 21, and therefore also between the grab shells 12, 22, resulting in a more uniform closure movement.
It is best shown in figure 3 that the grab 1 further comprises a closing line coupling element 103, connected to the first closing line 101 and to the second closing line 101’. The closing line coupling element 103 is configured to be connected to a closing winch of the crane. The closing line coupling element 103 is thus configured to recombine the closing lines 101, 101’ so that only a single, e.g. common closing line eventually extends towards the crane.
The grab 1 of the grab assembly 100 further comprises a lifting frame 104, with which the grab 1 is configured to be suspended from the crane. The grab 1 further comprises two lifting lines 102, which each extend between the lifting frame 104 and one of the grab shells 12, 22. In figure 3, a lifting line 102 is shown to extend between the lifting frame 104 and a lifting eye 36 attached to the second grab shell 22. As such, the lifting lines 102 are attached directly to the grab shells 12, 22 via the lifting eyes 38.
Alternatively, lifting lines may extend from the lifting frame 104 towards lifting eyes 37 attached to the lever arms 11, 21. These lifting eyes 37 are located at the first, i.e. lower ends of the lever arms 11, 21, to be positioned close to the grab shells 12, 22.
The lifting frame 104 is adapted to be suspended from two hoisting lines of the crane and is typically suspended above the grab 1, i.e. above the grab shells 12, 22 and the lever arms 11, 21 .The lifting frame 104 allows the hoisting line from the crane above it to extend in a substantially vertical direction V, whereas the lifting lines 102 towards the grab shells 12, 22 do not extend entirely vertical. Hence, the lever arms 11, 21 and the grab shells 12, 22 are wider than the lifting frame 104.
It is further shown in figure 3 that the first lever arm 11 and the second lever arm 21 are rotatable relative to each other about the direct pivot connection 31 to move the grab 1 between the fully closed position and the fully opened position by rotation of the lever arms 11, 21 over an opening angle ® — ©. In the present embodiment, the opening angle ® — © is defined in a range between 100° and 170°, i.e. at 135°. The grab 1 thus enables a relatively large opening angle © — © and thus a relatively large spread between the grab shells 12, 22 in the fully opened position. The opening angle © — ® will remain lower than 170° to prevent that the closing cable 101 will contact the bulk material that is to be grabbed.
It is best shown in figure 4 that the first grab shell 12 comprises a first planar cutting edge 17 and that the second grab shell 22 comprises a second planar cutting edge 27. In the fully closed position of the grab 1, as shown in figure 4, the planar cutting edges 17, 27 are aligned non-parallel relative to each other. Furthermore, the planar cutting edges 17, 27 are set at an angle relative to the bent bottoms 13, 23 of the grab shells 12, 22. In the fully opened position of the grab 1, as shown in figure 3, the planar cutting edges 17, 27 are aligned parallel to each other and parallel to the vertical direction V.
In the present grab 1, the grab shells 12, 22 do not have cutting edges aligned horizontally and parallel to each other in the closed position of the grab 1. Instead, the grab shells 12, 22 contact each other here with the cutting edges 17, 27, which define a discrete cutting edge angle ¢ in between them, i.e. defined between the cutting edge 17 of the first grab shell 12 and the cutting edge 27 of the second grab shell 22 in the fully closed position ofthe grab 1. As a result of the cutting edges 17, 27 not being aligned parallel to each other, the cutting edge angle ¢ is unequal to 180°. In particular, the cutting edge angle ¢ is defined in a range between 100° and 170°, i.e. at 135°.

Claims (21)

CONCLUSIESCONCLUSIONS 1. Kabelbediende mechanische grijper, bijvoorbeeld een met vier kabels bediende mechanische grijper, voor het hanteren van lasten, in het bijzonder voor het hanteren van bulkgoederen, omvattend: - een eerste hefboomarm, omvattend een eerste uiteinde en een tegenoverliggend tweede uiteinde, waarbij de grijper een eerste grijperschaal omvat die is gemonteerd aan het eerste uiteinde van de eerste hefboomarm, - een tweede hefboomarm, omvattend een eerste uiteinde en een tegenoverliggend tweede uiteinde, waarbij de grijper een tweede grijperschaal omvat die is gemonteerd aan het eerste uiteinde van de tweede hefboomarm, - een directe scharnierverbinding tussen het tweede uiteinde van de eerste hefboomarm en het tweede uiteinde van de tweede hefboomarm die vrij is van schijven, waarbij de eerste hefboomarm een sluitlijn-bevestigingspunt omvat, waarbij de tweede hefboomarm een initiële sluitlijn-geleidingsschijf omvat, en waarbij de grijper is ingericht om een sluitlijn te ontvangen, die is ingericht om te worden bevestigd aan het sluitlijn-bevestigingspunt en is ingericht om zich uit te strekken vanaf het sluitlijn-bevestigingspunt, via de initiële sluitlijn-geleidingsschijf, direct naar een kraan van waaraf de grijper is ingericht om te worden opgehangen.1. Cable-operated mechanical grab, for example a four-cable operated mechanical grab, for handling loads, in particular for handling bulk goods, comprising: - a first lever arm, comprising a first end and an opposite second end, wherein the grab comprises a first gripper shell mounted at the first end of the first lever arm, - a second lever arm comprising a first end and an opposing second end, the gripper comprising a second gripper shell mounted at the first end of the second lever arm, - a direct pivot connection between the second end of the first lever arm and the second end of the second lever arm which is free of sheaves, the first lever arm comprising a closing line attachment point, the second lever arm comprising an initial closing line guiding disc, and wherein the grapple is arranged to receive a closing line, which is arranged to be attached to the closing line attachment point and arranged to extend from the closing line attachment point, through the initial closing line guide disk, directly to a crane from which the grab is is arranged to be hung. 2. Kabelbediende mechanische grijper volgens conclusie 1, waarbij de eerste hefboomarm en de tweede hefboomarm elk een tussensectie hebben, tussen hun respectievelijke eerste uiteinden en tweede uiteinden, waarbij het sluitlijn-bevestigingspunt is voorzien op de tussensectie van de eerste hefboomarm, en waarbij de initiële sluitlijn-geleidingsschijf is voorzien op de tussensectie van de tweede hefboomarm.A cable operated mechanical grab as claimed in claim 1, wherein the first lever arm and the second lever arm each have an intermediate section, between their respective first ends and second ends, the closing line attachment point being provided on the intermediate section of the first lever arm, and wherein the initial closing line guide disc is provided on the intermediate section of the second lever arm. 3. Kabelbediende mechanische grijper volgens conclusie 2, waarbij de eerste hefboomarm aan diens tussensectie een opvolgende sluitlijn-geleidingsschijf omvat, en waarbij de sluitlijn is ingericht om zich uit te strekken vanaf het sluitlijn-bevestigingspunt, via de initiële sluitlijn-geleidingsschijf en via de opvolgende sluitlijn-geleidingsschijf, direct naar de kraan van waaraf de grijper is ingericht om te worden opgehangen.A cable-operated mechanical grab as claimed in claim 2, wherein the first lever arm at its intermediate section includes a successive closing line guiding disk, and wherein the closing line is arranged to extend from the closing line attachment point, through the initial closing line guiding disk and through the succeeding closing line. closing line guiding disc, directly to the crane from which the grab is arranged to be suspended. 4. Kabelbediende mechanische grijper volgens een van de voorgaande conclusies, waarbij de tweede hefboomarm een tweede sluitlijn-bevestigingspunt omvat aan diens tussensectie, waarbij de eerste hefboomarm een tweede initiële sluitlijn-geleidingsschijf omvat op diens tussensectie, en waarbij de grijper is ingericht om een tweede sluitlijn te ontvangen, die is ingericht om te worden bevestigd aan het tweede sluitlijn-bevestigingspunt en is ingericht om zich uit te strekken vanaf het tweede sluitlijn-bevestigingspunt, via de tweede initiële sluitlijn- geleidingsschijf, direct naar de kraan.A cable-operated mechanical grab as claimed in any preceding claim, wherein the second lever arm includes a second closing line attachment point on its intermediate section, the first lever arm includes a second initial closing line guide sheave on its intermediate section, and wherein the grab is adapted to hold a second receive a closing line arranged to be attached to the second closing line attachment point and arranged to extend from the second closing line attachment point, through the second initial closing line guide disk, directly to the crane. 5. Kabelbediende mechanische grijper volgens conclusie 4, waarbij de tweede hefboomarm een tweede opvolgende sluitlijn-geleidingsschijf omvat aan diens tussensectie, en waarbij de tweede sluitlijn is ingericht om zich uit te strekken vanaf het tweede sluitlijn- bevestigingspunt, via de tweede initiële sluitlijn-geleidingsschijf en via de tweede opvolgende sluitlijn-geleidingsschijf, direct naar de kraan van waaraf de grijper is ingericht om te worden opgehangen.A cable operated mechanical grab as claimed in claim 4, wherein the second lever arm includes a second successive closing line guide sheave at its intermediate section, and wherein the second closing line is arranged to extend from the second closing line attachment point through the second initial closing line guiding sheave and via the second successive closing line guide disc, directly to the crane from which the grab is arranged to be suspended. 6. Kabelbediende mechanische grijper volgens een van de voorgaande conclusies, verder omvattend: - een hijsframe, waarmee de grijper is ingericht om aan de kraan te worden opgehangen, bijv. vanaf ten minste een hefkabel van de kraan, - ten minste een eerste hijskabel, die zich uitstrekt tussen het hijsframe en een van de eerste grijperschaal en de eerste hefboomarm, en - ten minste een tweede hijskabel, die zich uitstrekt tussen het hijsframe en een van de tweede grijperschaal en de tweede hefboomarm.6. Cable-operated mechanical grab as claimed in any of the foregoing claims, further comprising: - a hoisting frame, with which the grab is arranged to be suspended from the crane, e.g. from at least one lifting cable of the crane, - at least a first hoisting cable, extending between the hoisting frame and one of the first grab shell and the first lever arm, and - at least one second hoisting rope extending between the hoisting frame and one of the second grab shell and the second lever arm. 7. Kabelbediende mechanische grijper volgens conclusie 6, waarbij de eerste grijperschaal en de tweede grijperschaal elk ten minste een respectievelijk hijsoog omvatten, waarbij de ten minste ene eerste hijskabel is verbonden met het ten minste ene hijsoog van de eerste grijperschaal, en waarbij de ten minste ene tweede hijskabel is verbonden met het ten minste ene hijsoog van de tweede grijperschaal.The cable-operated mechanical grab of claim 6, wherein the first grab shell and the second grab shell each comprise at least one respective lifting eye, the at least one first hoisting cable being connected to the at least one lifting eye of the first grab shell, and wherein the at least one lifting eye a second hoisting rope is connected to the at least one hoisting eye of the second grab shell. 8. Kabelbediende mechanische grijper volgens een van de voorgaande conclusies, waarbij de directe scharnierverbinding een scharnierpen omvat, die zich ten minste gedeeltelijk uitstrekt door een of meer lagerzittingen in de eerste hefboomarm en door een of meer lagerzittingen in de tweede hefboomarm.A cable-operated mechanical grab as claimed in any preceding claim, wherein the direct pivot connection comprises a pivot pin extending at least partially through one or more bearing seats in the first lever arm and through one or more bearing seats in the second lever arm. 9. Kabelbediende mechanische grijper volgens een van de voorgaande conclusies, waarbij de grijperschalen door middel van een losneembare verbinding zijn gemonteerd aan de hefboomarmen.A cable-operated mechanical grab according to any one of the preceding claims, wherein the grab shells are mounted to the lever arms by means of a releasable connection. 10. Kabelbediende mechanische grijper volgens conclusie 6 en conclusie 9, waarbij de eerste hefboomarm en de tweede hefboomarm elk ten minste een respectievelijk hijsoog omvatten aan hun eerste uiteinden, waarbij de ten minste ene eerste hijskabel is verbonden met het ten minste ene hijsoog van de eerste hefboomarm, en waarbij de ten minste ene tweede hijskabel is verbonden met het ten minste ene hijsoog van de tweede hefboomarm.A cable-operated mechanical grab according to claim 6 and claim 9, wherein the first lever arm and the second lever arm each include at least one lifting eye, respectively, at their first ends, the at least one first lifting cable being connected to the at least one lifting eye of the first lever arm, and wherein the at least one second hoisting cable is connected to the at least one hoisting eye of the second lever arm. 11. Kabelbediende mechanische grijper volgens conclusie 9 of 10, waarbij de losneembare verbinding tussen de hefboomarmen en de grijperschaal een penverbinding en/of een boutverbinding omvat.11. Cable-operated mechanical grab according to claim 9 or 10, wherein the releasable connection between the lever arms and the grab shell comprises a pin connection and/or a bolt connection. 12. Kabelbediende mechanische grijper volgens een van de voorgaande conclusies, waarbij de grijperschalen elk een gebogen bodem omvatten, een respectievelijke zijwand omvatten aan tegenoverliggende zijden van de gebogen bodem en verstijvingsribben omvatten tussen de zijwanden en zich evenwijdig aan de zijwanden uitstrekkend omvatten.A cable-operated mechanical grab as claimed in any preceding claim, wherein the grab shells each include a curved bottom, include a respective side wall on opposite sides of the curved bottom, and include stiffening ribs between the side walls and extending parallel to the side walls. 13. Kabelbediende mechanische grijper volgens conclusie 12, waarbij elk van de grijperschalen verder ten minste een deksel omvat, die zich elk uitstrekken tussen een zijwand en een verstevigingsribbe, om een inwendige van de respectievelijke grijperschaal tenminste gedeeltelijk af te sluiten.The cable-operated mechanical grab of claim 12, wherein each of the grab shells further comprises at least one cover, each extending between a side wall and a reinforcing rib, to at least partially close an interior of the respective grab shell. 14. Kabelbediende mechanische grijper volgens conclusie 13, waarbij elk van de deksels zich verder uitstrekt tussen de zijwanden en over de verstevigingsribben om het inwendige van de respectievelijke grijperschaal in hoofdzaak af te sluiten.The cable operated mechanical grab of claim 13, wherein each of the covers further extends between the side walls and over the reinforcing ribs to substantially close the interior of the respective grab shell. 15. Kabelbediende mechanische grijper volgens een van de voorgaande conclusies, waarbij de eerste grijperschaal en de tweede grijpschaal elk een vlakke snijrand omvatten, waarbij, in de volledig gesloten positie van de grijper, de vlakke snijranden niet-parallel zijn uitgelijnd ten opzichte van elkaar, en waarbij, in de volledig geopende stand van de grijper, de vlakke snijranden zijn uitgelijnd in een in hoofdzaak verticaal vlak.A cable-operated mechanical grab according to any one of the preceding claims, wherein the first gripper shell and the second gripper shell each comprise a planar cutting edge, wherein, in the fully closed position of the gripper, the planar cutting edges are aligned non-parallel to each other, and wherein, in the fully open position of the gripper, the planar cutting edges are aligned in a substantially vertical plane. 16. Grijpersamenstel voor het hanteren van lasten, in het bijzonder voor het hanteren van bulkgoederen, omvattend: - de kabelbediende mechanische grijper volgens een van de voorgaande conclusies, - ten minste een sluitlijn, ingericht om de grijper vanuit een geopende positie, bijv. een positie waarin de grijperschalen op afstand van elkaar zijn geplaatst, te brengen in een gesloten positie, bijv. een positie waarin de grijperschalen elkaar raken, waarbij de sluitlijn een proximaal uiteinde omvat dat is aangepast om te worden verbonden met een kraan, in het bijzonder met een sluitlier van de kraan, en een tegenoverliggend distaal uiteinde dat is bevestigd aan het sluitlijn-bevestigingspunt van de eerste hefboomarm, en waarbij de sluitlijn, vanaf diens distale uiteinde, rechtstreeks naar de kraan wordt geleid via de initiële sluitlijn-geleidingsschijf op de tweede hefboomarm.16. Gripper assembly for handling loads, in particular for handling bulk goods, comprising: - the cable-operated mechanical gripper according to any one of the preceding claims, - at least one closing line, adapted to move the gripper from an open position, e.g. position in which the gripper shells are spaced from each other to a closed position, e.g. a position in which the gripper shells touch, the closing line comprising a proximal end adapted to be connected to a tap, in particular to a closing winch of the crane, and an opposite distal end attached to the closing line attachment point of the first lever arm, with the closing line being guided, from its distal end, directly to the valve via the initial closing line guide disc on the second lever arm . 17. Grijpersamenstel volgens conclusie 16, waarbij de sluitlijn vanaf diens distale uiteinde direct naar de kraan wordt geleid via de initiële sluitlijn-geleidingsschijf op de tweede hefboomarm en via de opvolgende sluitlijn-geleidingsschijf op de eerste hefboomarm.The gripper assembly of claim 16, wherein the closing line is guided from its distal end directly to the tap via the initial closing line guide disk on the second lever arm and via the subsequent closing line guide disk on the first lever arm. 18. Grijpersamenstel volgens conclusie 16 of 14, verder omvattend een tweede sluitlijn, omvattend een proximaal uiteinde dat is ingericht om te worden bevestigd aan de kraan, in het bijzonder aan de sluitlier van de kraan, waarbij een distaal uiteinde van de tweede sluitlijn is bevestigd aan het tweede sluitlijn- bevestigingspunt van de tweede hefboomarm, en waarbij de tweede sluitlijn vanaf diens distale uiteinde direct naar de kraan wordt geleid via de tweede initiële sluitlijn-geleidingsschijf op de eerste hefboomarm.A grasper assembly according to claim 16 or 14, further comprising a second closing line including a proximal end adapted to be attached to the tap, in particular to the closing winch of the tap, a distal end of the second closing line being attached to the second closing line attachment point of the second lever arm, and wherein the second closing line is guided from its distal end directly to the valve via the second initial closing line guide disc on the first lever arm. 19. Grijpersamenstel volgens conclusie 18, waarbij de tweede sluitlijn vanaf diens distale uiteinde direct naar de kraan wordt geleid via de tweede initiële sluitlijn-geleidingsschijf op de eerste hefboomarm en via de tweede opvolgende sluitlijn-geleidingsschijf op de tweede hefboomarm.The gripper assembly of claim 18, wherein the second closing line is guided from its distal end directly to the tap via the second initial closing line guide disk on the first lever arm and via the second subsequent closing line guide disk on the second lever arm. 20. Grijpersamenstel volgens een van de conclusies 16 — 19, verder omvattend ten minste een hefkabel, ingericht om de grijper aan de kraan te hangen, waarbij de ten minste ene hefkabel een proximaal uiteinde omvat dat is aangepast om te worden verbonden met de kraan, in het bijzonder met een hijslier van de kraan, en een tegenoverliggend distaal uiteinde dat is bevestigd aan de grijper, en waarbij het distale uiteinde van de ten minste ene hefkabel bij voorkeur indirect is verbonden met de grijperschalen, bijvoorbeeld via het hijsframe, via de ten minste ene eerste hijskabel en via de ten minste ene tweede hijskabel.A grab assembly according to any one of claims 16 to 19, further comprising at least one lifting cable adapted to suspend the grab from the crane, the at least one lifting cable including a proximal end adapted to be connected to the crane, in particular with a hoisting winch of the crane, and an opposite distal end attached to the grab, and wherein the distal end of the at least one lifting cable is preferably indirectly connected to the grab shells, e.g. via the hoisting frame, via the ten at least one first hoisting rope and via the at least one second hoisting rope. 21. Werkwijze voor het hanteren van bulkgoederen door middel van een grijpersamenstel volgens een van de conclusies 16 — 20, omvattend de stappen van: - het naar een laadplaats bewegen van de grijper in diens geopende positie, - het trekken aan de ten minste ene sluitlijn om de grijper in diens gesloten positie te brengen, om bulkgoed te grijpen binnen de grijperschalen; - het naar een losplaats bewegen van de grijper; en - het vrijgeven van de tenminste ene sluitlijn om de grijper in diens geopende positie te brengen, om het bulkgoed te lossen uit de grijperschalen.A method for handling bulk goods by means of a gripper assembly according to any one of claims 16 - 20, comprising the steps of: - moving the gripper in its open position to a loading location, - pulling the at least one closing line to move the gripper into its closed position, to grip bulk goods within the gripper shells; - moving the grab to an unloading location; and - releasing the at least one closing line to bring the gripper into its open position in order to unload the bulk material from the gripper shells.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB349571A (en) * 1929-10-07 1931-05-21 Naamlooze Vennootschap Havenbe Grab for heapable goods
DE1816869A1 (en) * 1968-12-24 1970-07-02 Demag Zug Gmbh Multi-rope grab
DE3030472A1 (en) * 1980-08-08 1982-03-18 Peiner Maschinen- Und Schraubenwerke Ag, 3150 Peine Suspension system for grab jaws - includes opening cables at ends and closing cables wound around pairs of wheels between
CN201932814U (en) * 2010-11-21 2011-08-17 杨礼琚 Multi-type reverse scissors grab

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB349571A (en) * 1929-10-07 1931-05-21 Naamlooze Vennootschap Havenbe Grab for heapable goods
DE1816869A1 (en) * 1968-12-24 1970-07-02 Demag Zug Gmbh Multi-rope grab
DE3030472A1 (en) * 1980-08-08 1982-03-18 Peiner Maschinen- Und Schraubenwerke Ag, 3150 Peine Suspension system for grab jaws - includes opening cables at ends and closing cables wound around pairs of wheels between
CN201932814U (en) * 2010-11-21 2011-08-17 杨礼琚 Multi-type reverse scissors grab

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