Abstract:
A device for locating loads destined to be applied to a cable- and/or chain- and/or hydraulic-type lifting plant, in which the plant includes a lifting system to which a gripping element for a load is connected via a cable or chain system, and is provided with projector for projecting visual indications correlated with the position or the displacements of the load.

Description:
RELATED APPLICATION 
       [0001]    The present application hereby claims priority under 35 U.S.C. Section 119 to Italian Patent application number MI2010A002279, filed Dec. 14, 2010, the entire contents of which are hereby incorporated by reference. 
       FIELD OF INVENTION 
       [0002]    The present invention relates to a device for locating loads in lifting plants. 
       BACKGROUND 
       [0003]    The device of the invention can be applied to cable-lifting apparatus, such as bridge cranes, construction cranes, motor winches and chain or hydraulic apparatus or like apparatus (for example lifting clamps, beams or the like) destined to lift and move loads. 
         [0004]    As is known, bridge cranes are machines destined to lift and displace materials and goods, both in outdoor and indoor situations, and are generally constituted by a bridge crane, mobile in a horizontal direction along a pair of tracks or pathways and provided with a crossbar for a carriage on which a pulley block is mounted that can move horizontally along the crossbar and to which a pulley is connected, which pulley is provided with a hook for gripping and raising the objects. 
         [0005]    One or more cables are applied to the pulley block, which via a system of pulleys, return pulleys and hooks enable the weights to be lifted and moved. 
         [0006]    In the prior art, these operations are performed with the load positioned solely by sight and depending on the experience of the lifting plant operator. 
         [0007]    In practice, the operator nears the load, after having identified it, and directs the lifting hook to which the load is to be attached in order to be raised. 
         [0008]    During this maneuver, the operator begins by moving the bridge crane and simultaneously lowering the hook which thus serves as a reference for locating the crane with respect to the load to be lifted. 
         [0009]    This maneuver however involves some dangers, especially where there are people present in the loading area, for example workers in a workshop; it is quite common for these workers to be instructed to take care with regard to the hook moving towards them. 
         [0010]    Further, during the displacement, the hook oscillates absolutely unpredictably and randomly, a phenomenon which increases at it approaches the ground. 
       SUMMARY 
       [0011]    An aim of the present invention is to obviate the above-cited drawbacks, considerably increasing the degree of precision and safety in the movement of the loads of the lifting system. 
         [0012]    A further aim of the invention is to provide a safety device that locates the load during the functioning of the lifting plant. 
         [0013]    A further aim of the invention is to attain the result in a way which is practical and economical. 
         [0014]    The aims are attained with a device for locating loads destined to be applied to a cable or chain or hydraulic lift plant, or a combination thereof, in which the plant includes a lift system to which is connected, via a cable or chain system, a gripping element for a load, the device being provided with a projector that projects visual indications correlated to the position or the displacements of the load. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    Further characteristics and advantages of the invention will emerge from a reading of the following description, provided by way of non-limiting example, with the aid of the figures illustrated in the accompanying figures of the drawings, in which: 
           [0016]      FIG. 1  illustrates a lift plant according to a first embodiment of the invention; 
           [0017]      FIG. 2-4  illustrate different embodiments of the invention; 
           [0018]      FIG. 5  is a further embodiment of the invention; 
           [0019]      FIG. 6  is an embodiment applied to an underhook lifting beam; 
           [0020]      FIG. 7  is a further embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]      FIG. 1  illustrates a safety device for a cable lift plant of the invention, denoted in its entirety by reference number  10 . 
         [0022]      FIG. 1  shows the plant  10  in a schematic view, comprising a bridge crane provided with a pulley block  11 , in turn provided with a hook  12 , and destined to raise or lower a load (not illustrated for the sake of simplicity) by means of a system of cables activated by a pulley block  18  mounted on a crossbar  17  provided with a carriage  49 . In turn, the crossbar  17  is mobile along two parallel uprights  15 ,  16 , which can slide in a perpendicular direction to the movement of the crossbar  17  which is performed by displacing two heads  13 ,  14  along two beams  33 ,  34 . 
         [0023]    In the invention, the plant  10  comprises at least a light projector designed to project light indications correlated to the position of the hook  12  or to the overall dimension thereof. 
         [0024]    In general the projectors usable can be laser or light beam projectors; in any case they will be such as to project points, lines, crosses, circles and combinations thereof or other forms, with the aim of projecting on the ground or other appropriate surface a series of light beams that are visible to the operators, and which identify the center of the hook  12 . 
         [0025]    In particular, in the case of the plant  10 , the projectors  21 ,  22  are configured such as to project a cross  23  on the ground to identify the center of the hook  12 . 
         [0026]    In a variant, not illustrated for reasons of simplicity, the projects can be configured such as to create three lines which create a three-line pattern on the ground which the operator identifies as a hook  12  position or a loading zone. 
         [0027]    An alternative is illustrated in  FIG. 2 , in which a plant  20  is represented, which comprises a projector  24  which is able to project a line  25  onto the ground which identifies the median line in a longitudinal direction of the bridge crane. A second alternative is represented in  FIG. 3 , in which a plant  30  is illustrated, which provides projectors  24  able to project lines  25  onto the ground which identify the median line in a transversal direction of the bridge crane. The system enables the trajectory of the bridge crane to be highlighted, as a warning to personnel internally of the operating area of the crane. 
         [0028]    A further realization of the invention is illustrated in  FIG. 4 , in which a plant is illustrated  40  that comprises projectors  27 ,  28  able to project a series of lines on the ground, which lines identify the delimitation of an operating area  29  to be made safe, and internally of which nobody must remain or enter. 
         [0029]    This can also occur by a combined use of a plurality of projected beams located for example on both heads  13 ,  14  of the bridge crane  10 - 40  and/or of the carriage  49 . 
         [0030]    A further example is the application of the projectors  61 ,  62  to an underhook bar  60  for guaranteeing its exact positioning, in a case, for example, of lifting 12-metre long iron sheet bundles performed by a 4-metre long bar. 
         [0031]    In cases such as the above, the operator has difficultly centering the load, and wrong centering causes the problem of having an inclined and therefore dangerous load. 
         [0032]    The use of two projectors  61 ,  62  situated at ends of the bar, which project two lines  63 ,  64  located at a predetermined distance (for example 12 meters) enables a precise positioning to be obtained, using the linear references thus-created ( FIG. 6 ). 
         [0033]    The invention can also be applied to motor cranes having a telescopic arm  70 , which reach considerable heights. 
         [0034]    These can position the arm while controlling the position of the hook  72 , for example by projecting the cross  71 , and the load can then be collected ( FIG. 5 ). In the case of construction cranes  80 , which reach considerable heights, the possibility for the operator to verify the position in which the virtual hook is positioned, for example by the projection of the cross  81 , enables not only an increase in the degree of safety, but also an acceleration in operating times ( FIG. 7 ). 
         [0035]    Another possible case of use is in positioning for special operations, such as kilns positioned on the ground or the like, in such a way that the light beam generated enables the operator more precisely to position the hook without having to approach the load; this can be left to after positioning has been done, such as to hook on the load. 
         [0036]    The invention further enables visual verification of any attempts at oblique loading, as it is well-placed to see that the hook is not in a position corresponding to its center of gravity during a loading attempt; this constitutes a further safety application for the lifting device. 
         [0037]    The invention is also applicable to clamps of various nature, for example for lifting coils, sheet metal or other types besides, with the aim of identifying the centering of the objects to be lifted. 
         [0038]    If associated to the system described in patent application MI2008A000901, by the same inventor, the invention enables orientation of the light beams which follow the position of the hook. 
         [0039]    In the above-cited document, to which reference is made for a more complete description and which is considered to be comprised as a whole in the present description, a three-axis accelerometer group is comprised and mounted such as to detect the displacements of the cable in the various spatial directions, taking account of the time and ambient temperature. 
         [0040]    In this case, the accelerometer system enables the beams to be directed following the positional indications of the accelerometer group itself. 
         [0041]    The present invention is provided with obvious advantages in terms of safety, namely the following. 
         [0042]    Firstly, the operator can translate the lift device while maintaining the hook raised and thus preventing causing a danger to other persons who might inadvertently be struck by the moving and swinging hook of the crane or bridge crane. Further, the hook located at the top of the bridge crane or the other lift device reduces its swinging. 
         [0043]    The invention enables fine precision in the positioning of the bridge crane or the other lift device for hooking on the load. 
         [0044]    With the use of remote commands instead of a command button panel, the operator can see the exact position of the virtual hook while remaining at a distance from the load and the bridge crane. 
         [0045]    The invention further offers the possibility of a faster sliding of the bridge crane or other lift device in full safety conditions and without creating danger to persons present in the loading and unloading operating area, with the possibility for persons to optically see the lift device in arrival in the area. The laser pointer is lit according to the forward or rearward advancement direction. 
         [0046]    The invention is applicable to any lift device, either already in existence or newly constructed. 
         [0047]    The use of projectors further enables projecting complex images such as direction arrows or shapes which are adaptable to the shape of the load. 
         [0048]    The use of positioning lasers positioned on the ground such as to form and visualize the center of the hook enables displacements of the lift device to be made with hook retained in a high position; it is only once that the visual reference of the hook is positioned on the load to be raised, and only then, that the operator can begin to lower the hook to perform the loading operation. 
         [0049]    It can be seen that the projector that projects visual indications of the invention are configured in such a way to project visual indications that indicate the position of the hook, both in case that a load is not present on the vertical of the hook, or in case a load is present on the vertical of the hook, and in this last case the visual indication is represented on the load itself. 
         [0050]    This effect can be obtained, for example but not exclusively, because the projecting visual indications projector is able to project cross forms, circle forms, three-lined elements or triangles or other forms. 
         [0051]    As a consequence, independently from the distance between the visual indications projector and the surface of projection, it is always possible to visualize one or more of the above described shapes, eventually having different dimensions in one or the other case. 
         [0052]    In general then, the visual indications can be configured in such a way to indicate the vertical of the gripping element or the loading zone independently from the distance between said visual indications projector and the surface on which said visual indication are projected. Obviously modifications or improvements can be brought to the invention, dictated by contingent or special requirements, without its forsaking the ambit of the invention as claimed herein below.