LIFTING DEVICE FOR FLAT SLABS

Description

The present invention relates to a lifting device for flat slabs, in particular a lifting device for large stone slabs. PRIOR ART Large, flat sheets are increasingly used in the construction industry, covering horizontal or vertical surfaces (cladding tiles up to 1800x3400 mm) or for framing transparent windows (clear glass). Although these sheets are typically thin, ranging from 1 to 12 mm, their significant size makes them quite heavy. Typically, on site, these panels must be individually removed from their packaging and transported by installers to the installation site, where they must be cut, drilled to size, and coated with glue on one side before being precisely positioned. It's clear that transport is difficult for operators due to factors such as size, weight, and weight distribution. Furthermore, due to their large surface area and thinness, the sheets must be lifted and held appropriately to prevent them from bending excessively under their own weight and ultimately breaking (especially if they have been machined and engraved). Since this is a well-known problem, several lifters for large slabs have already been offered on the market. Generally, these prior art devices consist of a pair of parallel bars, joined by a pair of transverse bars, equipped with suction cups designed to grip the flat surface of the slab at positions appropriately distributed around the center of gravity. Some of these known devices are illustrated for example in EU designs No 5646940-0012 and 5646940-0015 in the name of the same Applicant. However, these solutions are not very flexible and expensive and therefore present 67913 CMF FUMERÒ Srl There is room for improvement. In particular, given their sporadic use by operators, they are cumbersome and represent a tool immobilization that operators struggle to justify, which discourages their purchase and use. EP 3 702 105 describes a similar device, in which the longitudinal bars are adjustable in length by sliding together shorter sections. Each bar is also equipped with a plurality of suction cups, which are mounted on the mutually sliding bars via a complex interconnecting body. This solution offers a compact footprint, which is appreciated by operators during equipment transport, but at the cost of additional complexity and therefore cost-increasing costs for equipment used sporadically. PROBLEM AND SOLUTION The underlying problem of the invention is therefore to provide a lifting device that completely overcomes the aforementioned drawbacks. Specifically, the aim is to provide a lifter that is compact while maintaining a simple and economical structure. The aim is also to provide a lifter whose component parts, particularly the suction cups, are easily removable and therefore reusable for other applications, thus optimizing the purchase investment. These purposes are achieved by means of the features described in essential terms in the attached claims. BRIEF DESCRIPTION OF THE DRAWINGS Further features and advantages of the invention will, however, become more evident from the following detailed description of a preferred embodiment, given purely by way of example and not of limitation and illustrated in the attached drawings, in which: fig. 1 is a perspective view of a lifting device according to the present invention; Figs. 2A and 2B are two perspective views, respectively with and without the longitudinal and transverse bar, of the interconnecting body with the 67913 CMF FUMERÒ Srl suction cup grip; fig. 2C is a view similar to that of fig. 2B according to a different perspective; fig. 3 is a perspective view similar to that of fig. 1 according to a different version; Figs. 4A and 4B are broken-off perspective views with parts removed of the joint mechanism according to the invention in the open position; Figs. 5A and 5B are views according to two different perspectives of the lifting device according to the invention in the folded position; Figs. 6A, 7, 8, and 10 are views according to different perspectives of the lifting device according to the present invention in different configurations; Figs. 6B and 6C are detail views of the attachment with ground translation wheels; and Fig. 8A is a detail view of the feature identified in Fig. 8. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Referring to fig. 1, a slab lifting device 1 is shown, resting on a large slab L, for example 1800x3400 mm. In a manner known per se, the device 1 comprises two longitudinal bars 3a, 3b joined together by two transverse bars 4a, 4b by means of connecting bodies 5. The sets of longitudinal bars 3a, 3b and the two transverse bars 4a, 4b meet in the device 1 under conditions of perpendicularity (or almost perpendicularity). At least the longitudinal bars 3a and 3b are made up of tubular elements in which handle terminals 7 are inserted, which can slide therein, be adjusted and therefore be tightened by means of fastening means 8. According to the invention, two hinged joint elements 6a, 6b are provided approximately halfway along the longitudinal bars 3a and 3b. Fig. 4A illustrates in more detail the joint 6a and the longitudinal bar 3a on which it is installed. In particular, it can be noted that the longitudinal bar is made up of two perfectly aligned separate portions or segments, a first segment 30 and a second segment 31, placed next to each other at the head ends and joined by a hinge group 60. The hinge group 67913 CMF FUMERÒ Srl It consists of two brackets 60a and 60b joined together, free to rotate, by a hinge pin 60c which defines an axis of rotation perpendicular to the longitudinal axis of the bar segments 30 and 31. The two brackets 60a and 60b are configured with a sole 60', by means of which they are fixed to the bar segments 30 and 31, and two lateral wings 60 arranged on planes perpendicular to the axis of rotation of the pin 60c. The two wings 60 of one bracket 60a are separated by a greater distance than the wings 60 of the other bracket 60b: in this way, the two brackets can rotate at least 180° on top of each other, partially interpenetrating. Thanks to the presence of the hinge assembly 60, the two segments 30 and 31 can rotate relative to each other in a first direction, until they overlap one another. Reverse rotation is prevented by an alignment bar 61 which, in use (Fig. 4A), bridges the two segments. The alignment bar 61 is installed on the side opposite the hinge assembly 60. The alignment bar 61 is fixed firmly, by means of screws or rivets 62, to the second segment 31. Conversely, in correspondence with the first segment 30, the alignment bar 61 has a hole 63 suitable for receiving a threaded stem 64 of a knob or operating handle 65 integral with it. Preferably, the threaded stem 64 does not engage with a threaded hole provided directly in the segment 30 of the underlying bar, but engages in a threaded hole obtained in a plate 66 (visible in fig. 4B) which tightens the segment 30 in cooperation with the sole 60' of the opposing hinge group 60 by means of a pair of tie rods 67. Tightening the threaded stem 64 on segment 30 ensures consolidation of the hinge assembly, which maintains a stable and robust alignment between the two segments 30 and 31 of the longitudinal bars. Conversely, by unscrewing the threaded stem 64 and releasing the operating handle 65, the second segment 31 can rotate freely with respect to the first segment 30 by approximately 180°, until it reaches the configuration illustrated in Fig. 5A, in which one segment 30 overlaps the other 31 and the overall longitudinal dimensions are reduced by half (if the two segments 30 and 31 are of equal extension). Figs. 5A and 5B illustrate well the folded configuration of the device. 67913 CMF FUMERÒ Srl lift 1. To make the transition from the folded to the extended position of the device 1, it is sufficient to remove the threaded stem 64 with the handle 65, rotate the pair of first segments 30 of the two longitudinal bars until they abut against the alignment bars 61; subsequently, the threaded stem 64 is reintroduced and screwed into the respective threaded hole of the bar 66, tightening with the handle 65. Figs. 2 and 3 illustrate in detail connection means 5 arranged according to a preferred embodiment of the invention, for simultaneously clamping a longitudinal bar 3a, a transverse bar 4a and a suction cup V. As can be seen, the connection means 5 are mainly formed by a first pair of opposing grip elements, for example a lower one 50a and an upper one 50b, and a second clamp-type grip element 51, tightened together by means of a knob 52 equipped with a threaded stem 52a. The opposing gripping elements 50a and 50b are identical and have two shaped terminal wings and an intermediate saddle portion where the threaded stem 52a engages. The two opposing gripping elements 50a and 50b are arranged mirror-image to each other and then tightened together by means of the knob 52. Between the two homologous shaped terminal wings of the two opposing gripping elements 50a and 50b, one of the longitudinal bars 3a and 3b and, on the other, a handle of a suction cup V can be interposed and blocked. The tightening action between the two opposing gripping elements 50a and 50b, which occurs in the intermediate saddle area, allows the connection means to be tightened even if only the longitudinal bar 3a and 3b or only the handle of the suction cup V is interposed. The second U-bolt gripping element 51 consists of an inverted U-shaped bracket 51a, equipped with a short lateral flange 51b in which a hole is provided for insertion of the threaded stem 52a. One side of the U-shaped bracket 51a is fixedly fixed to the upper gripping element 50b, while the other side can be partially expanded and then tightened against the upper gripping element 50b by means of the knob 52 which acts on the flange 51b. 67913 CMF FUMERÒ Srl One of the cross bars can be inserted and locked inside the second clamping element 51. With this configuration, the connection body 5 is able to fix the longitudinal and transverse bars together and at the same time a suction cup equipped with a standard handle or even just one or two of these three components. In particular, note that the suction cup V illustrated by way of example has a cylindrical handle Vi which houses, for example, the vacuum pump that allows a vacuum to be created, in a known manner, inside the suction cup body. The suction cup V therefore constitutes an autonomous device, which can be separated from the connection means 5 and used for other purposes. As illustrated in Fig. 2A, the connecting means 5 can be used to fix a suction cup V at the intersection of a longitudinal bar 3a with a transverse bar 4b (as illustrated in Fig. 1). The same connecting means 5 can also be used in a different way, for example to fix a suction cup V at any position on a transverse bar or a longitudinal bar, as illustrated in Fig. 3. Advantageously, four connection means 5 can be used at the intersections between the longitudinal bars 3a and 3b and the transverse bars 4a and 4b to stabilize the frame of the lift 1. Subsequently, additional connection means 5 can be provided, in any position along the longitudinal bars 3a and 3b or the transverse bars 4a and 4b, to apply the suction cups V to the lifting device 1, in the positions most suitable for the specific sheet to be lifted. Since the connection body 5 can be easily opened, by acting on the knob 52, to release the bars and / or the suction cup V, the system can be easily assembled as desired by the operator and even the standard suction cups V can be easily released from the lift and moved to another position on the frame of the device 1 or made available for other uses. Through the connection means 5, the operator can also select the type of standard suction cup V based on his preferences or market availability. For example, the suction cup V can be of the pump type 67913 CMF FUMERÒ Srl manual or electric vacuum. Fig. 6A illustrates the foldable lifting device 1 equipped with an accessory that allows it to slide on a support surface, typically the construction site floor. In particular, two ends on the same side of the crossbars 4a and 4b are provided with wheels 100a, 100b applied to tubular legs 101a, 101b. The latter are held in position on the crossbars 4a and 4b by suitable fastening means: for example, as illustrated in Figs. 6B and 6C, threaded shank knobs 102a, 102b may be provided that engage with stop nuts (not visible) inserted into longitudinal grooves S made in the crossbars 4a and 4b. Fig. 7 shows a variant of Fig. 6A, in which the legs equipped with wheels are applied to the ends on the same side of two longitudinal bars. The variant in Fig. 7 is shown as an example with only two suction cups V. Fig. 8 illustrates another variant of fig. 6A. In this case, a lift 200 comprises two longitudinal bars 201a, 201b and two transverse bars 202a, 202b connected to each other in a substantially perpendicular manner by means of connection means 203a-d at which respective suction cups V are provided. Further gripping suction cups V are mounted, by means of further connection means 204 and 205, in proximity to joints 206 and 207 of the longitudinal bars. Furthermore, at the ends of the crossbars 202a and 202b opposite those equipped with wheels, safety retaining brackets 208a and 208b are provided. In particular, the safety retaining brackets 208a and 208b are in the form of an arm with a proximal end fixed in an adjustable manner to the crossbar - for example by means of a tightening knob 209 (similar to the one used for the legs equipped with wheels) - and with a distal end shaped like a hook so as to embrace an edge of a Plate L adhering to the suction cups V (see detail in the enlargement of fig. 8A). These distal hooked ends, in normal conditions of use of the lift, are positioned close to the edge of the plate L - adjusting their extension along the crossbar and then fixing them with the knobs 209 - but do not come into active contact with the plate; only in the case in which one of the 67913 CMF FUMERÒ Srl suction cups V should lose their grip, they are able to act as a safety device and prevent the sheet from completely detaching from the frame of the lift 1, falling involuntarily to the ground. Fig. 9 shows an embodiment of the lift 1 without wheels but equipped with four safety retaining brackets, one for each end of the crossbars. If more than two crossbars are mounted, the safety retaining brackets may also be proportional in number. Fig. 10 illustrates another embodiment of the lift according to the invention, in which the two longitudinal bars are used without transverse reinforcement bars. If the slab L has small transverse dimensions, it may also be sufficient to use a single longitudinal bar. In general, in all the illustrated embodiments, the longitudinal bars 3a and 3b are preferably tubular with a square cross-section, as also illustrated. Since holding a square cross-section bar by hand can be unpleasant, especially under the weight of the plate L, the handle terminals 7 are preferably in the form of profiles with a substantially round cross-section. Advantageously, the profiles also have longitudinal grooves, suitable for engaging the stop nuts for the fastening means 8; in this case, preferably, straight strips of plastic material are provided to be inserted into the part of the grooves not engaged by the fastening means, so as to make the grip ergonomic and pleasant for the operators' hands. As can be seen, the lifter according to the invention perfectly achieves the objectives set out in the introduction. It is in fact composed of very simple and robust linear bars, joined by suitably shaped connecting bodies that make the suction cups easily accessible, which can also be used for other purposes. The presence of hinged joints allows the longitudinal bars to be folded back on themselves, significantly reducing the overall size of the lift during transport. Once the frame of lift 1 is folded back on itself (as illustrated in Fig. 5A), it can be easily stored in a transport bag that also contains all the various components and accessories. 67913 CMF FUMERÒ Srl It is understood, however, that the invention is not to be considered limited to the particular provisions described above, which constitute only exemplary embodiments of it, but that various variants are possible, all within the reach of a person skilled in the art, without thereby departing from the scope of protection of the invention itself, as defined by the claims that follow. It is intended, for example, that the transverse bars could also be equipped with hinge joints, or that particularly long longitudinal bars could be broken down into three sections and therefore also equipped with two hinge joints instead of one.

Claims

1. Lifting device for plates (1, 200) comprising: at least one longitudinal bar (3a, 3b, 201a, 201b), a plurality of connection means (5a-d, 203a-d, 204, 205) arranged to be coupled to said at least one longitudinal bar (3a, 3b, 201a, 201b) and to gripping suction cups (V), characterised in that said at least one longitudinal bar (3a, 3b) is made up of a first segment (30) and a second segment (31), joined together by hinged joint elements (6).

2. A plate lifting device (1, 200) as in claim 1, wherein said hinged joint members (6) comprise a hinge assembly (60), on one side of said first and second segments (30, 31), and an alignment bar (61) arranged on the opposite side of said first and second segments (30, 31).

3. A plate lifting device (1, 200) as in claim 2, wherein said hinge assembly (60) consists of two brackets (60a, 60b) rotatably joined together by a hinge pin (60c) which defines a rotation axis perpendicular to the longitudinal axis of said bar segments (30, 31), said brackets (60a, 60b) being configured with a sole (60') by which they are respectively fixed to said bar segments (30, 31).

4. Plate lifting device (1, 200) as in claim 2 or 3, wherein said alignment bar (61) is stably fixed to a second of said segments (31) while having removable coupling means (63, 64, 65) with said first segment (30).

5. Lifting device for plates (1, 200) as in any of the preceding claims, wherein said connecting means (5) comprise a first pair of opposing gripping elements (50a, 50b), and a second clamp-type gripping element (51), tightened together by means of manually operable tightening means (52, 52a).

6. Lifting device for slabs (1, 200) as in claim 67913 CMF FUMERÒ Srl 5, wherein said opposing gripping elements (50a, 50b) are identical and have two shaped terminal wings and an intermediate saddle portion where said manually operated clamping means (52, 52a) engage.

7. Lifting device for plates (1, 200) as in claim 6, in which said opposing gripping elements (50a, 50b) are arranged in a mirror-like manner to one another and between said homologous shaped terminal wings, one of said longitudinal bars (3a, 3b) can be interposed and blocked, on one side, and, on the other, a handle of a gripping suction cup (V).

8. Slab lifting device (1, 200) as in any of claims 5 to 7, wherein at least two longitudinal bars (3a, 3b, 201a, 201b) and also at least one transverse bar (4a, 4b) engaged in said second clamping element (51) are provided.

9. Lifting device for slabs (1, 200) as in any of the preceding claims, wherein said longitudinal bars (3a, 3b, 201a, 201b) are tubular and have ends suitable for housing sliding and adjustable accessories (7, R).

10. Lifting device for slabs (1, 200) as in 8 or 9, wherein the ends of said longitudinal (3a, 3b, 201a, 201b) or transverse (4a, 4b) bars can be alternatively coupled with roller legs (100, 101, 102) or arms with hook-shaped ends (208a, 208b).