CONSTRUCTION METHOD OF THE GRIPPING EQUIPMENT OF A LIFTING APPARATUS AND LIFTING APPARATUS PROVIDED WITH SUCH GRIPPING EQUIPMENT
20210354959 · 2021-11-18
Inventors
Cpc classification
B66C23/005
PERFORMING OPERATIONS; TRANSPORTING
International classification
B66C23/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
Gripping equipment for lifting apparatuses of the type comprising: a rigid support framework which is adapted to be fixed/attached to the lifting apparatus; and one or more manually controlled gripping members that are firmly fixed to said rigid support framework, and are adapted to grasp and hold a specific object to be moved; said rigid support framework comprising at least one rectilinear tubular element with polygonal cross-section, which is made of metal and has a sectional modular structure.
Claims
1. Gripping equipment (1) for lifting apparatuses (100) of the type comprising: a rigid support framework (2) which is adapted to be fixed/attached to the lifting apparatus (100); and one or more manually controlled gripping members (3) that are firmly fixed to said rigid support framework (2) and are adapted to grasp and hold a specific object to be moved; the gripping equipment (1) being characterised in that said rigid support framework (2) comprises at least one rectilinear tubular element with polygonal cross-section (10, 14), which is made of metal and has a sectional modular structure.
2. The gripping equipment according to claim 1, wherein said at least one rectilinear tubular element with polygonal cross-section (10, 14) comprises two rectilinear metallic section-bars (21) of given length and with a substantially C- or L-shaped cross-section, separate and distinct from one another, which are firmly fitted one into the other along the respective longer longitudinal edges, so as to form a rigid tubular structure with a polygonal cross-section that substantially copies the shape of said rectilinear tubular element (10, 14).
3. The gripping equipment according to claim 2, wherein each rectilinear metallic section-bar (21) is provided, along its two longer longitudinal edges, with a male-female coupling system which is complementary to that of the other rectilinear metallic section-bar (21), and allows the two rectilinear metallic section-bars (21) to firmly fit one into the other along the same longer longitudinal edges.
4. The gripping equipment according to claim 3, wherein each rectilinear metallic section-bar (21) has, along one of its two longer longitudinal edges, a series of protruding teeth (22) that jut out cantilevered from the section-bar spaced side-by-side to one another, and are adapted to engage as many coupling seats (23) formed on the facing longer longitudinal edge of the other rectilinear metallic section-bar (21).
5. The gripping equipment according to claim 4, wherein the protruding teeth (22) are substantially plate-shaped.
6. The gripping equipment according to claim 4, wherein the protruding teeth (22) are substantially regularly spaced along the whole length of the longer longitudinal edge of the section-bar, and/or wherein the coupling seats (23) have a shape substantially complementary to that of the corresponding protruding teeth (22).
7. The gripping equipment according to claim 4, wherein the coupling seats (23) are pass-through slotted-holes or openings.
8. The gripping equipment according to claim 7, wherein the protruding teeth (22) are dimensioned so as to engage in pass-through manner said pass-through slotted-holes or openings.
9. The gripping equipment according to claim 2, wherein the two rectilinear metallic section-bars (21) are firmly fixed to one another also via welds along said longer longitudinal edges.
10. The gripping equipment according to claim 2, wherein at least one of the two rectilinear metallic section-bars (21) is made in one piece starting from a single metal plate of appropriate thickness, which is cut and bent on itself so as to form said rectilinear metallic section-bar (21).
11. The gripping equipment according to claim 10, wherein said metal plate has a nominal thickness ranging between 2 and 15 mm.
12. The gripping equipment according to claim 2, wherein said at least one rectilinear tubular element with polygonal cross-section (10, 14) additionally comprises at least one longitudinal guide or lath (24) which extends parallel to the longitudinal axis of the rectilinear tubular element with polygonal cross-section (10, 14), and is placed in abutment against the rigid tubular structure formed by said rectilinear metallic section-bars (21).
13. A construction method of the gripping equipment (1) of a lifting apparatus (100) wherein the gripping equipment (1) comprises: a rigid support framework (2) which is adapted to be fixed/attached to the lifting apparatus (100) and includes at least one rectilinear tubular element with polygonal cross-section (10, 14); and one or more manually controlled gripping members (3) that are firmly fixed on said rigid support framework (2), and are adapted to grasp and hold a specific object to be moved; said construction method being characterised in that it comprises the steps of: manufacturing, for said at least one rectilinear tubular element with polygonal cross-section (10, 14), a pair of rectilinear metallic section-bars (21) having a substantially C- or L-shaped cross-section; and then fitting the two rectilinear metallic section-bars (21) one into the other, along the respective longer longitudinal edges, so as to form a rigid tubular structure having a polygonal cross-section that substantially copies the shape of said rectilinear tubular element with polygonal cross-section (10, 14).
14. The construction method of the gripping equipment of a lifting apparatus according to claim 13, wherein the two rectilinear metallic section-bars (21) fit one into the other by means of a male-female coupling system placed along the longer longitudinal edges of the section-bars.
15. The construction method of the gripping equipment of a lifting apparatus according to claim 13, characterised by additionally comprising the step of welding the two rectilinear metallic section-bars (21) to one another along the respective longer longitudinal edges.
16. The construction method of the gripping equipment of a lifting apparatus according to claim 13, wherein the manufacturing of at least one of said rectilinear metallic section-bars (21) comprises the steps of: cutting a metal plate of appropriate thickness, so as to obtain a flat blank (200) having a substantially elongated rectangular shape; and then L-bending the flat blank (200) along at least one predetermined bending line, so as to form said rectilinear metallic section-bar (21).
17. The construction method of the gripping equipment of a lifting apparatus according to claim 13, characterised by additionally comprising the step of fixing a longitudinal guide or lath (24) onto at least one of said rectilinear metallic section-bars (21).
18. A manually-operated lifting apparatus (100) comprising: a supporting column (101); a movable beam (102) which is butt fixed to the supporting column (101) with the capability of swinging over a substantially horizontal plane; and a movable arm (103) that extends in cantilever manner from the distal end of the movable beam (102), and is butt fixed to the distal end of the movable beam (102) with the capability of freely rotating with respect to the latter about a first, substantially horizontal, rotation axis (B), so as to be able to swing over a second substantially vertical plane; the lifting apparatus (100) being characterised by additionally comprising a gripping equipment (1) which is realized according to claim 1, and is fixed/coupled to the distal end of the movable arm (103) so as to be directly supported by said movable arm (103).
19. The lifting apparatus according to claim 18, wherein said movable arm (103) is moreover fixed to the distal end of the movable beam (102) also with the capability of freely rotating with respect to the latter about a second, substantially vertical, rotation axis (C), so as to be able to swing also over a third substantially horizontal plane.
20. The lifting apparatus according to claim 18, characterised by additionally comprising a weight-balancing device (105) which is adapted to continuously compensate the weight of the movable arm (103), of the gripping equipment (1) and of the object that is temporarily integral therewith.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The present invention will now be described with reference to the accompanying drawings, which illustrate a non-limiting embodiment example thereof, wherein:
[0017]
[0018]
[0019]
[0020]
[0021] Figures from 5 to 8 schematically illustrate some steps of the construction of the tubular element with square cross-section illustrated in
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
[0023] With reference to
[0024] In other words, the gripping equipment 1 is particularly suitable to be mounted on a manually-operated lifting apparatus 100, which is capable of continuously compensating/balancing the weight of the gripping equipment 1 and of the object temporarily integral therewith, so as to allow a person to lift and freely move such object in the space with a minimum physical effort, preferably manually giving the gripping equipment 1 or the object a direct light push.
[0025] Preferably, the lifting apparatus 100 is additionally a pneumatic manipulator or similar.
[0026] With reference to
[0027] Preferably, the movable arm 103 is moreover fixed to the distal end of the movable beam 102 also with the capability of freely rotating with respect to the latter about a second rotation axis C preferably substantially vertical and/or anyway locally substantially perpendicular to axis B, so as to be able to swing over also a second plane preferably substantially horizontal.
[0028] The gripping equipment 1 is preferably firmly fixed/coupled to the distal end of the movable arm 103 so as to be directly supported by the movable arm 103.
[0029] More in detail, the gripping equipment 1 is preferably firmly fixed to the distal end of the movable arm 103, so as to remain suspended beneath the distal end of the movable arm 103.
[0030] Preferably, the gripping equipment 1 is furthermore fixed to the distal end of the movable arm 103 in a rigid, though easily removable manner.
[0031] More in detail, with reference to
[0032] In other words, the gripping equipment 1 is preferably fixed firmly and in removable manner to the curved terminal 104.
[0033] With reference to
[0034] More in detail, the weight-balancing device 105 is preferably adapted to vary on command the inclination of the movable arm 103 with respect to the vertical, and to continuously compensate the weight of the movable arm 103, of the gripping equipment 1 and of the object temporarily integral therewith, so that any possible further movement in space of the gripping equipment 1 and/or of the object temporarily integral therewith can be manually executed by the operator with a minimum physical effort, preferably acting directly on the gripping equipment 1 and/or on the object temporarily integral therewith.
[0035] Preferably, the lifting apparatus 100, or rather the pneumatic manipulator, is moreover also provided with a first blocking device 106 which, on command, is capable of blocking/preventing rotation of the movable beam 102 on the top of supporting column 101, around the axis A; and/or with a second blocking device 107 which, on command, is capable of blocking/preventing rotation of the movable arm 103 on the distal end of movable beam 102, around the axis C.
[0036] With reference to
[0037] More in detail, the electropneumatic air-supply assembly 109 is capable of adjusting the flow of pressurized air to and from the pneumatic cylinder 108 preferably so as to be able, in sequence: to lower the movable arm 103 so as to bring the gripping equipment 1 close to or in contact with the object to be picked up and moved; optionally to raise the movable arm 103 so as to bring the gripping equipment 1 and its load, i.e. the object to be moved integral therewith, at a given height from the ground; and then compensate the weight of the gripping equipment 1 and of its load, i.e. of the object to be moved, so that the further movements in space of the gripping equipment 1 and of its load can be manually operated by the operator, acting directly on the gripping equipment 1 with a minimum physical effort.
[0038] In the example shown, in particular, the blocking devices 106 and/or 107 are preferably electro-pneumatically operated, and are optionally supplied by the same pressurized-air source that supplies also the electropneumatic air-supply assembly 109 of the weight-balancing device 105.
[0039] More in detail, the blocking device 106 is preferably an electro-pneumatically operated disc-caliper braking assembly.
[0040] In other words, the blocking device 106 preferably comprises: a disc 110 of metallic material, which is rigidly fixed on the top of the supporting column 101, substantially coaxial to axis A; a pneumatically-operated caliper 111, which is integral with the movable beam 102, is slidingly fitted onto the disc 110, and is finally adapted to pinch, on command, the body of disc 110 so as to prevent any movement between the two elements; and a preferably electrically-operated control valve (not shown in the figures), which is adapted to control/adjust the flow of pressurized air to the caliper 111.
[0041] Likewise, the blocking device 107 is preferably an electro-pneumatically operated disc-caliper braking assembly.
[0042] In other words, the blocking device 107 preferably comprises: a disc 112 of metallic material, which is rigidly fixed to the distal end of movable beam 102 substantially coaxial to axis C; a pneumatically-operated caliper (not shown in the figures), which is integral with the movable arm 103, is slidingly fitted on the disc 112, and is finally adapted to pinch, on command, the body of disc 112 so as to prevent any movement between the two elements; and a preferably electrically-operated control valve (not shown in the figures), which is adapted to control/adjust the flow of pressurized air to the caliper 112.
[0043] With reference to
[0044] More in detail, the rigid support framework 2 is preferably adapted to be fixed/attached to the distal end of movable arm 103, or rather to the curved terminal 104, so as to remain suspended beneath the movable arm 103. Preferably, the rigid support framework 2 is moreover adapted to be fixed onto the distal end of the movable arm 103 in a rigid, though easily removable manner.
[0045] Additionally, the gripping equipment 1 preferably also comprises a manually-operated control unit 4 which is adapted to command the gripping member(s) 3, and is preferably fixed/attached to the rigid framework 2 in a position easily reachable by the operator.
[0046] Preferably, the control unit 4 of the gripping equipment 1 is furthermore adapted to command also the electropneumatic air-supply assembly 109 of the weight-balancing device 105 and/or the blocking devices 106 and/or 107.
[0047] More in detail, the control unit 4 is preferably adapted to open and close, on command, the control valves of the blocking devices 106 and/or 107.
[0048] Clearly the structure of the gripping equipment 1 varies depending on the type of object to be grasped.
[0049] In other words, the shape/structure of the rigid support framework 2 and the type and position of the gripping member(s) 3 to be used vary depending on the type of object to be grasped.
[0050] With reference to
[0051] Preferably, the gripping equipment 1 additionally includes also a blocking device 6 that is preferably placed at the rotating joint 5, and is capable of blocking/preventing, on command, the rotation of the rigid support framework 2 on the distal end of the movable arm 103, about axis D. The control unit 4 of the gripping equipment 1, in addition, is preferably adapted to command also the blocking device 6.
[0052] More in detail, also the blocking device 6 is preferably operated electro-pneumatically, and is optionally supplied by the same pressurized air source that supplies also the electropneumatic air-supply assembly 109 of the weight-balancing device 105 and/or the blocking devices 106 and/or 107.
[0053] With reference to
[0054] The blocking device 6, in turn, is preferably an electro-pneumatically operated disc-caliper braking assembly.
[0055] In other words, the blocking device 6 preferably comprises: a disc 7 of metallic material, which is rigidly fixed to the upper rotating section of rotating joint 5, so as to be substantially coaxial to the rotation axis D of the joint and integral with the distal end of the movable arm 103; a pneumatically-operated caliper 8, which is integral with the lower rotating section of rotating joint 5, is slidingly fitted on the disc 7, and is finally adapted to pinch, on command, the body of disc 7 so as to prevent any movement between the two rotating sections of rotating joint 5; and a preferably electrically-operated control valve (not shown in the figures), which is adapted to control/adjust the flow of pressurized air to the caliper 8.
[0056] Clearly, the control unit 4 is preferably adapted to open and close, on command, also the control valve of the blocking device 6.
[0057] With reference to
[0058] More in detail, said at least one rectilinear tubular element preferably has a cross-section with an equilateral convex polygon shape (i.e. with all the sides equal to one another) and/or an equiangular shape (i.e. with all the angles equal to one another).
[0059] More conveniently, said at least one rectilinear tubular element is preferably with roughly-squared cross-section, i.e. with a substantially rectangular or square cross-section.
[0060] Additionally, said at least one rectilinear tubular element is basically made up of two rectilinear metallic section-bars of given length and with a preferably L- or C-shaped cross-section, separate and distinct from one another, which are arranged adjacent to one another and are shaped so as to be able to firmly fit one into the other along the respective longer longitudinal edges, so as to form a rigid tubular structure with polygonal cross-section which substantially copies the shape of said rectilinear tubular element.
[0061] With reference to
[0062] Preferably, the rigid support framework 2 furthermore comprises: a second rectilinear tubular element 14 with a polygonal cross-section, and more conveniently with a roughly-squared cross-section, which is arranged in a substantially horizontal position, beside to the rectilinear tubular element 10, and is rigidly butt fixed to the side of the rectilinear tubular element 10 preferably by means of a third pair of plate-shaped connection brackets, so as to protrude cantilevered from the latter orthogonally to the longitudinal axis of the rectilinear tubular element 10 and/or to the lying plane of the rigid structure having a substantially inverted T-shape; and two further metallic transversal bars 15 preferably substantially rectilinear and/or monolithic, which are arranged in a substantially horizontal position, beneath the metallic transversal bar 12, are perpendicular to the metallic transversal bar 12, and are finally rigidly fixed to the metallic transversal bar 12 preferably in a substantially specular position on opposite sides the centerline of the metallic transversal bar 12.
[0063] The gripping members 3 are preferably firmly fixed to the metallic transversal bars 15.
[0064] More in detail, in the example shown, the gripping members 3 preferably include one or more suction cups which are fixed cantilevered beneath the metallic transversal bars 15 preferably in a manually adjustable manner, and are for example capable of holding a glass sheet or marble slab.
[0065] In other words, in the example shown, the gripping equipment 1 is preferably structured so as to be able to grasp and hold a glass sheet or marble slab.
[0066] The control unit 4 of gripping equipment 1, on the other hand, is preferably firmly fixed on the free end of the rectilinear tubular element 14.
[0067] With reference to
[0068] In other words, the rectilinear tubular element 10, and preferably also the rectilinear tubular element 14, is basically made up of two rectilinear metallic section-bars 21 of given length and with a substantially L-shaped cross-section, separate and distinct from one another, which are arranged adjacent to one another and are shaped so as to be able to be firmly fitted one into the other along the respective longer longitudinal edges, so as to form a rigid tubular structure with polygonal cross-section that substantially copies the shape of the rectilinear tubular element 10, 14.
[0069] More in detail, each rectilinear metallic section-bar 21 is preferably provided, along its two longer longitudinal edges, with a male-female coupling system which is complementary to that of the other rectilinear metallic section-bar 21, and allows the two rectilinear metallic section bars 21 to firmly fit one into the other along the longer longitudinal edges.
[0070] With reference to
[0071] Preferably, the protruding teeth 22 are furthermore spaced in a substantially regular manner along the entire length of the corresponding longer longitudinal edge of the rectilinear metallic section-bar 21, and the coupling seats 23 preferably have a shape substantially complementary to that of the corresponding protruding teeth 22.
[0072] In other words, each rectilinear metallic section-bar 21 is preferably provided with a series of protruding teeth 22 that jut out cantilevered from a first longer longitudinal edge of the section-bar, preferably spaced in a substantially regular manner along the entire length of the edge/section-bar; and with a series of coupling seats 23 that are distributed along the second longer longitudinal edge of the section-bar, each aligned with a respective protruding tooth 22.
[0073] Preferably, the coupling seats 23 present on each rectilinear metallic section-bar 21 moreover are pass-through slotted-holes or openings, and the protruding teeth 22 are dimensioned to extend in pass-through manner through said pass-through slotted-holes or openings.
[0074] Additionally, the two rectilinear metallic section-bars 21 are preferably firmly and permanently fixed to one another by means of welds along the longer longitudinal edges.
[0075] More in detail, some or all of the teeth of one or each rectilinear metallic section-bar 21 are preferably firmly fixed to the body of the other rectilinear metallic section-bar 21 by means of localised welds.
[0076] Clearly, if the rectilinear tubular elements 10 and 14 had an hexagonal cross-section, the two rectilinear metallic section-bars 21 would have a substantially C-shaped cross-section.
[0077] With reference to
[0078] The/each longitudinal lath 24 has the function of locally increasing the overall thickness of the piece, and is preferably rigidly fixed to the rigid tubular structure with polygonal cross-section formed by the two rectilinear metallic section-bars 21 by means of welds and/or transversal anchoring-screws.
[0079] Additionally, the longitudinal lath(s) 24 have a length preferably smaller than or equal to the overall length of the rigid tubular structure with polygonal cross-section formed by the rectilinear metallic section-bars 21.
[0080] In the example shown, in particular, the rectilinear tubular element 10 is preferably provided with two longitudinal laths 24, which have a length substantially equal to the overall length of the rigid tubular structure with polygonal cross-section, and are preferably placed opposite one another, inside the rigid tubular section with polygonal cross-section formed by the two rectilinear metallic section-bars 21. Preferably, the two longitudinal laths 24 are moreover firmly fixed each to a respective rectilinear metallic section-bar 21.
[0081] Clearly, the longitudinal lath(s) 24 could also be placed outside of the rigid tubular structure with polygonal cross-section formed by the two rectilinear metallic section-bars 21.
[0082] Moreover, in a different embodiment, the longitudinal lath(s) 24 could be replaced by one or more longitudinal guide 24 preferably made of metallic material, so as to allow the sliding mounting of other components.
[0083] With reference to
[0084] Additionally, at least one and more conveniently each rectilinear metallic section-bar 21 is preferably made in one piece starting from a single metal plate of appropriate thickness, which is cut and bent on itself so as to form the rectilinear metallic section-bar 21.
[0085] Preferably, said metal plate is furthermore made of steel and/or has a nominal thickness ranging between 2 and 15 mm (millimetres).
[0086] In the example shown, in particular, the metal plate that forms each rectilinear metallic section-bar 21, has a nominal thickness preferably ranging between 3 and 10 mm (millimetres).
[0087] Operation of lifting apparatus 100 and of gripping equipment 1 are easily inferable from what described above and thus do not need further explanations.
[0088] The production of gripping equipment 1, on the other hand, preferably provides for assembling the rigid support framework 2 and then fixing/mounting the gripping member/s 3 onto the rigid support framework 2.
[0089] The assembly of the rigid support framework 2, in turn, provides for making, for each rectilinear tubular element 10, 14 with sectional modular structure, a pair of rectilinear metallic section-bars 21 having a substantially C- or L-shaped cross-section (see
[0090] Additionally, the assembly of rigid support framework 2 provides, for each rectilinear tubular element 10, 14 with sectional modular structure, also for the step of welding the two rectilinear metallic section-bars 21 to one another along the respective longer longitudinal edges.
[0091] More in detail, with reference to Figures from 5 to 8, the assembly of rigid support framework 2 preferably provides for making at least one and more conveniently both the rectilinear metallic section-bars 21 that concur in forming the/each rectilinear tubular element 10, 14, in a single piece starting from a single metal plate of appropriate thickness, which is cut and bent on itself so as to form the rectilinear metallic section-bar 21.
[0092] In other words, with reference to
[0095] Preferably, said metal plate is further made of steel and/or has a nominal thickness ranging between 3 and 10 mm (millimetres).
[0096] Clearly, if the rectilinear tubular elements 10 and 14 had for example a hexagonal cross-section, the bending of the flat bank 200 would occur along two different bending lines □ parallel to the centerline of the bank, so as to form a rectilinear metallic section-bar 21 with a substantially C-shaped cross-section.
[0097] With reference to
[0098] After fitting the two rectilinear metallic section-bars 21 one into the other, the production of the or of each rectilinear tubular element 10, 14 preferably includes also the step of welding the two rectilinear metallic section-bars 21 to one another along the respective longer longitudinal edges.
[0099] With reference to
[0100] The advantages deriving from the particular structure of the rectilinear tubular element(s) 10, 14 that concur in forming the rigid support framework 2 of gripping equipment 1, are numerous.
[0101] Firstly, the particular sectional modular structure allows making rectilinear tubular elements 10, 14 of any shape starting from a single type of metal plate, with the remarkable simplifications in the supplying and storage of the materials that this entails.
[0102] In fact, from a single type of metal plate with nominal thickness for example equal to 3 mm (millimetres), it is possible to rapidly make rectilinear tubular elements with square cross-sections of 30×30 mm, 45×45 mm, 60×60 mm, 90×90 mm.
[0103] It is finally clear that modifications and variants can be made to the gripping equipment 1 and/or to the lifting apparatus 100 described above without however departing from the scope of the present invention.
[0104] For example, instead of being fixed to the ground, the supporting column 101 can be fixed to a movable slide which is capable of moving horizontally along a rail, which is preferably firmly anchored to the ceiling. In this embodiment, therefore, the supporting column 101 extends cantilevered from the movable slide downwards, and the movable beam 102 is preferably butt fixed onto the lower end of the supporting column 101.
[0105] In a further embodiment of the lifting apparatus 100, the pneumatic cylinder 108 and the electro-pneumatic control unit 109 of the weight-balancing device 105 could be replaced by an electrically-operated linear actuator and by an electronic control unit adapted to drive the linear actuator based on the signals coming from one or more load cells capable of detecting the forces acting on the suspended load.
[0106] In other words, the lifting apparatus 100 could be an electric manipulator.
[0107] As concerns regard instead the gripping equipment 1, in a first not-shown embodiment the rigid support framework 2 could lack the two metallic transversal bars 15. In this case, the gripping members 3 could be placed at the two ends of the metallic transversal bar 12, and could consist of two magnetic gripping assemblies for metal plates, preferably, though not necessarily, as those described in U.S. Pat. No. 6,663,154.
[0108] With reference to
[0109] Therefore, in this embodiment, the rigid support framework 2 comprises the sole rectilinear tubular element 10.
[0110] Preferably, the gripping member 3 moreover comprises: a pneumatically-operated pliers assembly 300, which is fixed cantilevered to the lower end of the rectilinear tubular element 10, on the side of the rectilinear tubular element 10, with the capability of freely rotating about a rotation axis E preferably locally substantially perpendicular to the longitudinal axis of the rectilinear tubular element 10, and thus substantially perpendicular to axis D; and preferably also a preferably electro-pneumatically operated, rotating actuator 301 that is capable of rotating, on command, the pliers assembly 300 about the axis E.
[0111] The control unit 4 (not shown in this figure) is preferably fixed on the side of the rectilinear tubular element 10 and is preferably adapted to control the pliers assembly 300 and/or the rotating actuator 301.
[0112] Clearly, the gripping member 3 could also be a large lifting hook firmly fixed to the lower end of the rectilinear tubular element 10, or a magnetic gripping assembly as the one described in U.S. Pat. No. 6,663,154.