Abstract
A device for lifting a steel reinforcement mat includes a grid of parallel rods in a first direction and, placed thereon and fastened permanently, parallel rods in a second direction, each according to a predetermined mesh width. The device has a hoisting frame suitable for being secured to a hoist. The hoisting frame has supporting elements on opposite sides positioned in such a way that when the hoisting frame rests on an uppermost steel reinforcement mat of a stack thereof, each supporting element is located in a respective mesh. The supporting elements are configured to slide in the first direction in such a way that during lifting, the supporting elements each support with a respective supporting surface exclusively rods in the second direction of exclusively the uppermost steel reinforcement mat. The supporting elements on the opposite sides slide away in the opposite direction to each other.
Claims
1.-13. (canceled)
14. A device for lifting a steel reinforcement mat comprising a grid of parallel rods in a first direction and, placed thereon and permanently fastened, parallel rods in a second direction, each according to a predetermined mesh width; the device comprising a hoisting frame suitable for being secured to a hoist; the hoisting frame comprising supporting elements on opposite sides positioned in such a way that when the hoisting frame rests on an uppermost steel reinforcement ma of a stack thereof, each supporting element is located in a respective mesh; and in which moreover the supporting elements are configured to slide in the first direction in such a way that during lifting, the supporting elements each with a respective supporting surface exclusively support rods in the second direction of exclusively the uppermost steel reinforcement mat and wherein the supporting elements on the opposite sides slide away in the opposite direction to each other.
15. The device according to claim 14, further comprising a coupling configured to connect the hoisting frame rigidly to the hoist.
16. The device according to claim 14, wherein the distance between the supporting elements is adjustable.
17. The device according to claim 14, wherein a supporting element comprises a border at right angles to one side of its respective supporting surface.
18. The device as according to claim 14, wherein a supporting element further comprises an interlock configured to lock a supported rod.
19. The device according to claim 18, wherein the interlock is a closing pin positioned at right angles on the supporting surface and configured to close the opening of the supporting element in which the supported rod is located.
20. The device according to claim 14, wherein the sliding of the supporting elements takes place hydraulically.
21. The device according to claim 14, further comprising a base configured to be secured to the hoisting frame in such a way that the hoisting frame rests on the steel reinforcement mat exclusively by means of the base.
22. The device according to claim 21, wherein the height of the base is adjustable in such a way that the distance between the underside of the base and the upper side of the supporting surfaces is at least equal to the thickness of the rods in the second direction.
23. The device according to claim 14, further comprising one or more magnets configured to attract the corners of the steel reinforcement mat.
24. The device according to claim 23, wherein the magnet is an electromagnet or a mechanically controlled lifting magnet.
25. The device according to claim 14, wherein the hoisting frame comprises two parallel beams connected by means of a connecting frame comprising the coupling, the parallel beams comprising a supporting element at each end.
26. A hoist comprising the device according to claim 14.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0051] The invention will now be described further with reference to the drawings, in which:
[0052] FIG. 1A shows schematically a device for lifting a steel reinforcement mat according to a first embodiment of the invention; and
[0053] FIG. 1B shows schematically a device for lifting a steel reinforcement mat according to a second embodiment of the invention; and
[0054] FIG. 2A shows schematically the device according to FIG. 1A placed on a steel reinforcement mat according to the first embodiment of the invention; and
[0055] FIG. 2B shows schematically the device according to FIG. 1B placed on a steel reinforcement mat according to the second embodiment of the invention; and
[0056] FIG. 3A is a schematic top view of the device according to FIG. 1A on the steel reinforcement mat; and
[0057] FIG. 3B is a schematic top view of the device according to FIG. 1B on the steel reinforcement mat; and
[0058] FIG. 4 shows schematically a device for lifting a steel reinforcement mat from a stack thereof according to one embodiment of the invention; and
[0059] FIG. 5 shows schematically a device during setting down of a steel reinforcement mat on a surface according to one embodiment of the invention; and
[0060] FIG. 6 shows schematically a detail of the device comprising a base according to one embodiment of the invention; and
[0061] FIG. 7A and FIG. 7B show schematically a detail of a supporting element of the device according to one embodiment of the invention; and
[0062] FIG. 8A-8C show schematically details of an embodiment of the invention with a closing pin for interlocking hook-shaped supporting elements; and
[0063] FIG. 9A-9B show schematically details of an embodiment of the invention with an internal hydraulic circuit for safe closing/opening of the supporting elements.
DESCRIPTION OF EMBODIMENTS
[0064] FIG. 1A shows schematically a first embodiment of the device for lifting a steel reinforcement mat according to the present invention. The device 114 comprises two parallel beams 100 and 101 and a connecting frame 102, which connects the parallel beams 100 and 101 to one another by means of, for example, a plate joint, such as plate joint 104. Other connections, for example such as a welded joint, are also possible. The parallel beams 100 and 101 together with the connecting frame 102 together form a hoisting frame that further comprises a coupling 107 suitable for securing the hoisting frame to a hoist, for example such as a building crane. In the first embodiment, the beams 100 and 101 are movable with respect to the connecting frame 102.
[0065] FIG. 1B shows schematically a second embodiment of the device for lifting a steel reinforcement mat according to the present invention. Corresponding elements in FIG. 1A and FIG. 1B are indicated with one and the same reference. In the embodiment of the device 114 that is shown in FIG. 1B, the parallel beams 100 and 101 and the connecting frame 102 form a rigid whole. The degree of freedom in the Z-direction is realized in this second embodiment at the level of the coupling 107, the central shaft 108 of which is designed to be extendable. During setting down of a steel reinforcement mat, the central shaft 108 will be pressed in under the weight of the hoist, and will be pushed out during lifting of a steel reinforcement mat. The second embodiment illustrated in FIG. 1B allows steel reinforcement mats that are stacked alternately—i.e. steel reinforcement mats that are stacked alternately with the transverse rods downward and with the transverse rods upward—to turn a steel reinforcement mat round and give it the same orientation as the steel reinforcement mat beneath it, for example with the transverse rods upward. This requires two operations: the steel reinforcement mat to be turned is first raised on the side with projecting rods, by means of two supporting elements, for example 112 and 113, so that the steel reinforcement mat is dangling; then the steel reinforcement mat, correctly oriented, is taken off onto the ground. Then the lifting mechanism will be rotated 90°—for example by means of a rotator on the hoist—and the steel reinforcement mat is raised, this time making use of the four supporting elements 110-113.
[0066] The device 114 is suitable for resting on a steel reinforcement mat. FIG. 2A illustrates the first embodiment of the device 114, the embodiment in FIG. 1A, placed on a steel reinforcement mat 202. FIG. 2B illustrates the second embodiment of the device 114, the embodiment in FIG. 1B, placed on a steel reinforcement mat 202. The steel reinforcement mat 202 comprises a grid of parallel rods 200 and 201. A first set of parallel rods is placed in a first direction, as illustrated by rods 200, called the longitudinal direction. In another direction, for example at right angles to this, called the transverse direction, a second set of parallel rods is placed, as illustrated by rods 201.
[0067] The steel reinforcement mat 202 may, for example, lie on a surface, as illustrated in FIG. 5. The steel reinforcement mat 202 will then, for example, serve as reinforcement for a concrete floor. The surface 502 is for example a foundation on a building site, on which a layer of concrete will be cast, after the steel reinforcement mat 202 has been set down thereon.
[0068] When the steel reinforcement mat 202 is lying on the surface 502, rods in one direction, for example the first direction 200, will come into contact with the surface 502, whereas rods in the other direction, the second direction 201, lie on top of the rods in the first direction 200 and do not come into contact with the surface 502. In other words, there will be a height difference between the rods 201 placed in the second direction and the surface 502. This is illustrated by detail 501 in FIG. 5.
[0069] The steel reinforcement mat 202 can also be stacked with other steel reinforcement mats on a stack 401, as illustrated in FIG. 4. The stack 401 of steel reinforcement mats then contains steel reinforcement mat 202, which lies at the top of stack 401. The stack then lies on surface 400.
[0070] The rods placed in the first direction 200 lie parallel to one another and a predetermined distance apart, also called mesh width 205. The rods placed in the second direction 201 also lie parallel to one another and at a predetermined mesh width 204. Mesh width 205 may be identical to mesh width 204, so that the steel reinforcement mat comprises square meshes, for example such as mesh 203. The mesh widths 204 and 205 may also differ from one another, giving rectangular meshes.
[0071] The device 114 further comprises supporting elements 110-113 on opposite sides. According to the first embodiment illustrated in FIG. 1A and the second embodiment illustrated in FIG. 1B, the device 114 comprises four supporting elements, namely 110, 111, 112 and 113. The supporting elements 110 and 111 are considered to lie on one and the same side, and this also applies to supporting elements 112 and 113. The supporting elements 110 and 113 are considered to lie on opposite sides, which also applies to supporting elements 111 and 112. The supporting elements 110-113 are configured to slide in one and the same direction, more specifically in the longitudinal direction of the parallel beams 100 and 101.
[0072] The device 114 is placed on the steel reinforcement mat 202 in such a way that the longitudinal direction of the parallel beams 100 and 101 corresponds to one of the two directions in which the rods are placed. According to the schematic representation in FIG. 2A and FIG. 2B, the device 114 is placed on the steel reinforcement mat 202 in such a way that the longitudinal direction of the beams 110 and 111 lies in the same direction as the rods 200 in the longitudinal direction. This is illustrated further in FIG. 3A for the first embodiment of the device 114 and FIG. 3B for the second embodiment of the device 114, in which the device 114 on the steel reinforcement mat 202 is in each case illustrated from a top view.
[0073] The supporting elements 110-113 comprise a supporting surface and, according to one embodiment, an interlock, as illustrated in FIG. 7A. Here, a detail of supporting element 113 is illustrated, comprising a supporting surface 702, an underside 700, interlock 106, and a border 704. FIG. 7B shows further details of the interlock 106. In one embodiment, this interlock 106 comprises a spindle 711, a spindle cylinder 712 and a spring 713.
[0074] The supporting elements 110-113 are, moreover, positioned in such a way that the mutual distances between them allow the device 114 to be placed on the steel reinforcement mat 202 in such a way that each supporting element 110-113 is located in a mesh of the steel reinforcement mat 202. Moreover, when the supporting elements 110-113 are located in a respective mesh, in a starting position they do not touch a rod in the first direction 200, nor a rod in the second direction, nor a surface under them. Therefore the hoisting frame of the device 114 rests on the steel reinforcement mat 202. According to one embodiment, the device 114 further comprises a base 601 as illustrated in FIG. 6, which may be used to allow the device 114 to rest on the steel reinforcement mat 202.
[0075] The base 601 is configured for setting the distance 603 between the bottom of the base 601 when secured to the device 114 and the bottom of the supporting elements 110-113. This distance 603 should be at least equal to the thickness of the rods placed in the direction at right angles to the longitudinal direction of the beams 100 and 101, thus in the schematic illustration in FIG. 2A-2B and FIG. 3A-3B in direction 201 in such a way that these rods can be supported when the supporting elements 110-113 slide under these rods 201.
[0076] In order to place the device 114 stably and allow it to rest on the steel reinforcement mat 202, according to one embodiment four bases are provided, more specifically two per beam 100-101, at positions 120-123. Each base, such as base 601, can be secured to the device 114 by placing connecting pieces, such as connecting pieces 604 and 605, in specially provided openings of a respective beam 100-101, wherein one and the same opening is provided in the bases themselves, such as for base 601. More specifically, base 601 is secured to the device 114 via two cross-bars 604 and 605.
[0077] In order to set the height of the base 602, in other words the distance 603, various openings, which lie at different distances relative to the underside of the device 114, are provided in the beams 100-101. Said openings are illustrated by 606 and 607, each of which is provided at a different distance with respect to the underside of the device 114. Thus, with regard to cross-bar 605, the base 601 can be secured to the device via opening 606 or 607. The other cross-bar 604 then comes in another opening, so that the base 601 is connected to the device 114 via the two bars 604-605. Openings for securing the base 601 are illustrated further by the openings in position 120 in FIG. 1A.
[0078] The device 114 is thus placed on the steel reinforcement mat 202 in such a way that the ends of the beams 100-101, and more specifically the supporting elements 110-113 are located above a mesh, as illustrated with positions 300-303 in FIG. 3A. Then the device 114 is lowered onto the steel reinforcement mat 202, so that the bases rest thereon, and each supporting element 110-113 is located in a mesh. This is illustrated further in FIG. 4 by references 402 and 403.
[0079] The supporting elements 110-113 are located in a respective mesh and owing to the distance 603, the underside of a supporting element, for example underside 700 of supporting element 113, is located not lower than the plane defined by the upper side of the rods placed in direction 200 of the first underlying steel reinforcement mat under steel reinforcement mat 202 of the stack 401.
[0080] Then the supporting elements 110-113 slide outward, i.e. in the sense illustrated by 602 for supporting element 113, and the sense 608 for supporting element 110. Sliding thus occurs in an identical direction, but opposite sense for supporting elements that are located on opposite sides.
[0081] According to the embodiment illustrated in FIG. 7A, the supporting elements have a tapering supporting surface, such as supporting surface 702 for supporting element 113, so that when the supporting elements slide outward, each supporting element slides under a transverse rod and the supporting surface, such as 702, slides toward the rod under which the respective supporting element slides, and in this way raises the steel reinforcement mat. According to the embodiment illustrated in FIG. 7A, a supporting element 113 further comprises a border 704, so that when the supporting surface 702 does not slide toward the rod, the border 704 will slide toward it in such a way that the supporting element 113 clamps and raises the steel reinforcement mat somewhat. The horizontal sliding of the supporting elements under the transverse rods of the steel reinforcement mat may take place pneumatically or hydraulically, or may be accomplished in some other way. FIG. 7A shows for example a hydraulic cylinder 705, which moves the supporting element 113 horizontally. Hydraulic cylinders of this kind are operated by the operator of the hoist to which the hoisting device is coupled. A hoist, for example a building crane, is typically equipped with a hydraulic connection operable by the operator of the building crane. FIG. 7B is a detail drawing of the supporting element 113 with underside 700, tapering supporting surface 702, border 704, and above that a housing with spindle 711, spindle cylinder 712 and spring 713 in one possible embodiment of interlock 106. The spindle cylinder 712 forms part of the supporting element 113 and thus moves horizontally with it—back and forth—propelled by hydraulic cylinder 705. The spindle cylinder 712, spindle 711 and spring 713 are provided from considerations of safety: together they form an interlock 106, which will lock the rod that is carried by the supporting element 113 as soon as said rod is carried, in such a way that the steel reinforcement mat cannot fall during lifting. It is only when a rod breaks at the point where it is carried by a supporting element that the steel reinforcement mat may still be left dangling, but the steel reinforcement mat will not fall, so that even then the situation remains safe. The opening and closing of the spindle 111 must take place automatically, i.e. without the intervention of the operator, to exclude human errors, which create danger. For this reason pump cylinders 902 are provided, as shown in FIG. 9A and FIG. 9B. When the hoisting device is placed on a stack of reinforcement mats or on the ground, the jib will press in the central shaft 108 of the coupling 107. FIG. 9A shows the hoisting device with central shaft 108 pulled out, whereas FIG. 9B shows the hoisting device with central shaft 108 pushed in. When the central shaft 108 is pressed in, the latter will in its turn operate the pump cylinders 902, for example via skates. A rigid connection is shown in FIG. 9, but an embodiment with cam roller and skate offers tolerance with respect to the end position of the central shaft because the central shaft does not then have to be down completely before the spindle cylinders are open. The pump cylinders 902 are connected via an internal hydraulic circuit to the spindle cylinders 712 in the respective supporting elements, such as supporting element 113 in FIG. 7A-7B. The pump cylinder 902 thus pumps oil or some other hydraulic fluid to the spindle cylinder 113 so that spindle cylinder 113 is pushed open and the spindle 711 or closing pin of the interlock 106 is opened. As soon as the pump cylinder 902 is no longer pressed in (as a result of lifting of the hoisting device, withdrawal of the central shaft 108 and upward movement of for example skates) or when the connection between pump cylinder 712 and spindle cylinder 902 is broken, the spring 713 will push the spindle cylinder 712 shut, so that the spindle 711 or closing pin will close the opening of the closing element 713 and a safe situation is created. As an alternative to hydraulic drive of the spindle cylinders, the hoisting device may be provided with an electric battery, one or more electromagnets to pull the spindle cylinders upward, making use of electrical energy of the battery, and a detection mechanism to detect that the hoisting device is on the ground or on the stack of steel reinforcement mats in order to activate the electromagnet. Other forms of energy transmission such as mechanical energy transmission or pneumatic energy transmission may also be considered for converting the downward motion of the hoisting device at the moment of touching the ground or steel reinforcement mat into an upward motion of spindle cylinders which move the supporting elements and conversely, an upward motion of the hoisting device starting from the ground or a stack being converted automatically into a downward motion of the spindle cylinders so that the supporting elements are closed and a safe situation is created during lifting of a steel reinforcement mat.
[0082] The four supporting elements in positions 110-113 thus slide outward and then, according to one embodiment, the rods are locked as described above.
[0083] Then the device can be lifted, for example by means of a hoist coupled to the device 114 via coupling 107. According to one embodiment, the coupling also allows the device 114 to be rotated when lifted, by a rotator on the hoist. This is illustrated by the sense of rotation 206.
[0084] According to one embodiment, when the steel reinforcement mat 202 is raised it can be attracted, at the ends, by a magnet, for example such as an electromagnet 600 that is activated when the steel reinforcement mat 202 is lifted from the stack 401. These optional magnets allow the corners of the steel reinforcement mat to be raised a little so that the hooks or supporting elements can slide under the transverse rods more easily. In other words the magnets contribute to better gripping of the steel reinforcement mats, especially when the corners of a steel reinforcement mat would hang down.
[0085] Next, the steel reinforcement mat 202 is placed in a location provided for the purpose, as illustrated in FIG. 5. The steel reinforcement mat 202 can then be set down completely on the surface 502, wherein the supporting elements 110-113 usually touch the surface 502, as illustrated by 500. The supporting elements 110-113 slide back inward horizontally, after the interlock 106 is unlocked, in a sense opposite to 602 and 608 in such a way that the supporting elements 110-113 are located in a mesh and no longer under the rods that were supported.
[0086] After this, the device 114 can be lifted again in such a way that the steel reinforcement mat 202 is still lying on the surface 502 and wherein the device 114 can then go and lift the next steel reinforcement mat from the stack 401, in order to place al the steel reinforcement mats from the stack 401 in a required location.
[0087] FIG. 8A-8C show in detail an embodiment of the hoisting device with a closing pin 806 for locking a hook-shaped supporting element 803 at the ends of the parallel beams 800 and 801. FIG. 8A and FIG. 8B also show a steel reinforcement mat with longitudinal rods 200 and transverse rods 201. After the hook-shaped supporting elements 803 have been pushed outward and support a transverse rod 201, closing pin 806 is let down vertically until the closing pin 806 reaches the supporting surface (or a recess provided therein). This preferably takes place completely automatically by means of an internal circuit as described above, referring to FIG. 7A-7B and FIG. 9A-9B. In this way, the opening of the hook-shaped supporting element 803 is closed or locked in such a way that the supported transverse rod 201 cannot move out of it during lifting of the steel reinforcement mat. In a variant embodiment, the spindles/closing pins may perform a rotating or pivoting motion instead of a vertical motion in order to close the supporting elements and lock the transverse rods.
[0088] Although the present invention has been illustrated on the basis of specific embodiments, it will be clear to a person skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention can be implemented with various modifications and adjustments while remaining within the scope of the invention. The present embodiments must therefore be regarded in all aspects as illustrative and not restrictive, wherein the scope of the invention is described by the appended claims and not by the foregoing description, and all modifications that fall within the meaning and scope of the claims are consequently incorporated herein. In other words it is considered that this includes all modifications, variations or equivalents that fall within the scope of the underlying basic principles and whose essential attributes are claimed in this patent application. In addition, the reader of this patent application will understand that the words “comprising” or “comprise” do not exclude other elements or steps, that the word “a” does not exclude a plural, and that a single element may fulfill the functions of various devices that are stated in the claims. Any references in the claims are not to be interpreted as a limitation of the claims in question. The terms “first”, “second”, “third”, “a”, “b”, “c” and the like, when used in the description or in the claims, are used in order to distinguish between similar elements or steps and do not necessarily describe a successive or chronological order. Similarly, the terms “top”, “bottom”, “over”, “under” and such are used for the purpose of description and they do not necessarily refer to relative positions. It is to be understood that these terms are mutually interchangeable in the right circumstances and that embodiments of the invention are able to function according to the present invention in other sequences or orientations than those described or illustrated in the foregoing.
