Abstract:
A lifting device for handling of loads by suspension, especially maritime containers, includes:  
     an attaching body ( 21 ) including axial guidance and immobilization means ( 35, 36 ) and rotation guiding means ( 23 ),  
     a gripping device ( 24 ) passing through the body, in which it is held by the guidance and immobilization means and which, on the outside of the body, includes a coupling end ( 26 ) with an alternating rotation drive transmission ( 28 ) and opposite it, the shouldered head ( 30 ),  
     and a stress sensor ( 40 ) measuring the traction applied to the seizing device after coupling with the mortise, during container lifting and handling operations.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention concerns the field of machines, installations and/or devices for lifting, intended to handle heavy loads, and concerns more particularly but not exclusively lifting machinery of the mobile and self-propelled type which, as handling equipment, use a lifting beam supported by a suspension.  
           [0002]    As a preferred but non-limitative application, the invention refers more particularly to the area of container lifting and handling machinery, as is often used in seaport loading and unloading areas through which heavy loads are routed and handled, in particular rectangular box-shaped containers which it is necessary to be able to move, transport, lift, lower and stack with optimum safety.  
           [0003]    In the general area described above, more particularly involved in maritime applications, it is customary to use lifting-handling machinery, generally self-propelled, of the tracked or wheeled type and which have, on a suitable superstructure, a suspension lifting beam which is orientable and generally adjustable in several directions so as to be adaptable to standardized or other gauges of the loads to be handled.  
           [0004]    In the particular application case of maritime transport containers, the lifting beam is mounted at the end of a beam or boom, telescopic or not. To ensure the required function, it is obviously necessary to provide for technical facilities making it possible to establish or break at will the material structural link between the suspension lifting beam and the load, in particular the container.  
           [0005]    The means described in brief in the above are well known and can be considered as satisfactory for the essential function of lifting and handling.  
           [0006]    The current trends of container handling are generating the use of increasingly heavy loads varying from one container to another, even if the gauge is the same. Therefore, a particular problem to be taken into consideration is the exact evaluation of the weight of each container so as to be able to determine accurately the safety factor, both for the lifting and handling machine and for the principle of centering and loading, especially for loading on a ship.  
           [0007]    That is why it is increasingly essential to carry out individual weighing for each load so as to evaluate whether the safety factor and the weight are not exceeded, and whether particular steps have to be considered concerning lifting, handling, loading, centering or, yet again, capabilities of vertically stacking several containers of the same gauge size.  
           [0008]    These weighing operations are lengthy, requiring the use of a scale, which are not conducive to easy movement of the lifting and handling machines, in particular for loading and unloading areas or those used for storage of these containers, meaning frequently picking up operations and in all, representing a major factor that has an impact on the economic balance of the lifting and handling phase.  
           [0009]    In addition, these necessary and different operations are not liable to supply sufficient accuracy, meaning that the invoicing of the service related to the weighing-handling task is penalized similarly.  
           [0010]    That is why it has been recommended to adapt the methods of evaluation of the weight to the lifting and handling machine so as to obtain, immediately and in real time, information that covers the general concern mentioned in the above.  
           [0011]    To do this, in general, it has been recommended to use stress-sensing facilities, for instance, directly on the lifting actuators for a boom, which facilities, themselves well known, react immediately with the weight that the machine is desired to lift in suspension.  
           [0012]    Experiments carried out on the above basis have indicated that the principle referred to did not give sufficiently accurate information about the loaded weight. This inaccuracy is probably due to the distance between the point of suspension of the load, for instance at the end of the boom and the lifting machines, which distance, by a mechanical stress, induces inaccurate evaluations, giving incorrect estimations which, by accumulation, can result in situations that are outside safety standards and are liable to cause accidents that could result in human injury. In addition, this inaccuracy is no longer acceptable considering the relatively high price of the lifting-handling service to be provided for third parties.  
           [0013]    It is noteworthy that a problem of the same type arises in measuring the loads transported by the lifting hook of a crane, for instance a telescopic one.  
         SUMMARY OF THE INVENTION  
         [0014]    Therefore, the purpose of the invention is to address the need that is currently being experienced of having, in real time, accurate information about the weight being lifted, while simply bringing in adaptations of technical means which were previously combined to handle the task of lifting-handling from known types of machines.  
           [0015]    To achieve the above objective, the purpose of the invention is a stress sensor for a lifting and/or handling device including a lifting device equipped with an attaching for a “suspended” load, is characterized in that it includes:  
           [0016]    a support body and a bearing cap which, together, define at least one fluid compression chamber and are designed to be interposed,  
           [0017]    pressure measuring facilities within the compression chamber.  
           [0018]    According to one characteristic of the invention, the support body and the bearing cap have a hole designed to accommodate a suspension rod of the attaching device.  
           [0019]    According to another characteristic of the invention, the compression chamber is annular in a shape. In a preferred but not strictly essential manner, the compression chamber and the reception bore of the suspension rod are then more or less coaxial.  
           [0020]    Another purpose of the invention is a lifting device for a lifting-handling machine including at least one attaching body equipped with a load attaching device, characterized in that it includes a stress sensor according to the invention, interposed between the attaching body and the attaching device.  
           [0021]    According to one embodiment of the invention, the lifting device forms a rotary attaching weighing lock for a container lifting-handling machine load take-up lifting bar characterized in that:  
           [0022]    the attaching body has means of guiding and immobilization of the guide facilities in rotation in the axial direction,  
           [0023]    the attaching device has a rod, generally cylindrical in shape, passing through the attaching body and the stress sensor, retained by guide and immobilization facilities and which include, outside the body, a coupling end-fitting with an alternating drive transmission and on the opposite end, a shouldered head designed to cooperate with the oblong mortise shape of the container.  
           [0024]    In another embodiment of the invention, the lifting device is a crane hook characterized in that:  
           [0025]    the attaching body has axial guidance and immobilization means and rotation guidance means,  
           [0026]    the attaching device includes a hook extending in a rod passing through the body and the stress sensor in which it is maintained by immobilization and guide means and which, opposite the hook, has a bearing head on the stress sensor cap, inserted between the attaching body and the attaching device. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]    Various other characteristics are described below with reference to the attached illustrations which, as non-limitative examples, depict the embodiments of the object of this invention.  
         [0028]    [0028]FIG. 1 is a schematic side elevation view of a lifting-handling machine, in particular for containers.  
         [0029]    [0029]FIG. 2 is a schematic plan view approximately along the line II-II of FIG. 1.  
         [0030]    [0030]FIG. 3 is a schematic elevation view similar to FIG. 1 but illustrating a phase for the commissioning of the lifting-handling machine.  
         [0031]    [0031]FIG. 4 is a partial perspective view showing, at a larger scale, a detail of the method used in one of the components of the lifting-handling machine according to FIGS.  1  to  3 .  
         [0032]    [0032]FIG. 5 is a perspective view showing at a larger scale the objects of the invention.  
         [0033]    [0033]FIG. 6 is a sectional view approximately according to drawing VI-VI of FIG. 5.  
         [0034]    [0034]FIG. 7 is a particularly cutout elevation view of another form of implementation of a stress sensor according to the invention on a lifting hook equipped with a crane sheave.  
         [0035]    [0035]FIG. 8 is a sectional view similar to FIG. 6, but illustrating at a larger scale the implementation of a stress sensor on the crane hook.  
         [0036]    [0036]FIG. 9 illustrates the implementation of a stress sensor according to the invention, on a simple crane hook without a shave. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0037]    [0037]FIGS. 1 and 2 show, as an application example, a lifting-handling machine described generally by reference  1 . A machine like this includes a chassis  2  supported by independent means of movement such as wheels  3 , or yet again tracks that are not shown, which means are made self-propelling by means of any appropriate motorization system. Chassis  2  supports a control cab  4  and a structure, or even a bearing superstructure  5  on which a jib  7 , normally oriented in the longitudinal plane of symmetry of chassis  2 , is articulated by a horizontal shaft  6 . However, it should be considered that in some cases, structure  5  may consist of a tower, which is then adjustable through a vertical axis.  
         [0038]    Jib  7  may be telescopic or not and may be adjusted in elevation by swiveling about axis  6  by means of one or several actuators  8 , generally hydraulic, at least single-acting, interposed between a reinforcing harness  9  and chassis  2 .  
         [0039]    At the jib head  10 , jib  7  includes means of suspension and orientation  11  of lifting beam  12 , which is generally constructed as shown in FIG. 2, by a generally long-shaped box beam  13  which may be moved by an orientation tower  11   a,  so that its longitudinal axis x-x′ forms any angle, or even a zero angle with the longitudinal axis y-y′ of job  7 .  
         [0040]    Box beam  13  has two opposed telescopic half-beams  14  adjustable for their spread, generally but not necessarily symmetrically. At the end, each half-beam supports a flange  15 , which, as a lifting device, is provided with seizing or attaching locks  16 , for instance two of them.  
         [0041]    Therefore, lifting beam  12  is adjustable, at least in length, so as to match the gauge of the containers, such as  20 , which, as illustrated in FIG. 3, must be lifted and handled to be loaded or off-loaded or stored and stacked in a temporary storage area for instance, the port platform of a sea loading-unloading port.  
         [0042]    It is essential to consider the above example as an illustration only, because the purpose of the invention refers to any type of suspension, lifting or handling beam adapted to a suitable supporting structure from which it is necessary to handle a load by suspension.  
         [0043]    [0043]FIG. 3, in this application, shows that through locks  16  and the appropriate adjustment of the length of jib  7  and its elevator orientation at the least, it is possible to grip and grasp any container  20  to ensure its lifting, transport or even orientation to meet handling requirements. It should be noted that in the working position, container  20  forming the load to be transported is suspended by means of the attaching locks or devices  16  from lifting beam  12 .  
         [0044]    [0044]FIG. 14 shows in greater detail, although schematically, the partial composition of lifting beam  12  from box beam  13  supporting one of the outer half-beams  14 , at the end of which is flange  15  extending transversally to the axis of half-beam  14 , and whose two ends are provided with two locks  16  turned downward from a reference phase, for instance  17 , forming part of flange  15 .  
         [0045]    As understood by the invention, it should be considered that the constructive characteristic of the lifting beam  12  is part of the knowledge of the man of the art, in the same way as are the slaving devices to be implemented in some cases to ensure the complete functionalities as offered by this type of lifting beam.  
         [0046]    It should also be considered that if, under the terms of the drawings and the particular application referred to, a lifting beam like  12  includes, as lifting devices, four gripping or attaching locks  16 ; some applications may use a different number of locks while remaining within the field of the invention.  
         [0047]    A gripping lock such as  16 , includes as shown in FIGS. 5 and 6, attaching plate  21  so that lock  16  is removable with respect to flange  15  in the illustrated example, or with respect to any bearing structure of an equivalent type.  
         [0048]    Attaching plate  21  defines a through passage  22  lined with a guide sleeve  23  defining a clear bore for an attaching or gripping device  24  comprising essentially a so-called suspension rod  25 , generally cylindrical in shape. Rod  25  passes through opening  22  and includes a first suitable terminal part  26  formed by a coupling end on which is mounted a clevis  27  which, being removable, is suitable for connection to a control transmission  28 , generally consisting of a connecting rod or, yet again, by the piston shaft of a pneumatic, hydraulic, electric or mechanical actuator. In the example used in this application, transmission  28  is of the antagonist double-acting type so as to be able to control simultaneously rotation about their axis z-z′ of the rods  25  forming the two locks  15  on each flange.  
         [0049]    For reasons appearing from the above, but also known in the technique, transmission  28  is designed to be able to control the rotation of rod  25  through an angular development of approximately 90° from a position P 1 , as illustrated in FIG. 5 to a position P 2  and vice versa.  
         [0050]    The terminal part of rod  25  opposite end  26  has a gripping or attaching head  30  with two shoulders  31  placed diametrically opposite each other on a common direction at right angles to the z-z′ axis and that are aligned with two extensions  32  of sleeve  23  in the stable idle position P 1 , as illustrated in FIG. 5.  
         [0051]    In addition, rod  25 , through a spherical bearing surface  35 , is supported on seat  36  consisting of attaching body  21 . Spherical bearing surface  35  is preferably made of an independent part immobilized endwise and angularly on rod  25 .  
         [0052]    It is advantageous for the attaching body to be completed by a position sensor  38  extending downwards and held to protrude by means of an elastic return device  39 .  
         [0053]    The function to be provided by this type of lock is to enable head  30  to engage in the oblong mortise shape of the container, such as  20 , whose presence is detected by information supplied by position sensor  39 .  
         [0054]    When head  30  has penetrated, transmission  28  is controlled to rotate the attaching or seizing device  24  from position P 1  to P 2  so that shoulders  21  are then placed under the bearing edges forming the mortise, and thus establishing a link between lock  16  and container  20 , as is already known.  
         [0055]    According to the invention, at rod  25 , it is intended to install a stress sensor working on the traction applied to device  24  in the direction of arrows f 1  and f 2 , as soon as attaching body  21  is raised in the direction of arrow f 1 , once head  30  has gripped the corresponding mortise of container  20 , as already described.  
         [0056]    Using a traction stress sensor such as this, it is possible to have precise and localized information independent of the mechanical stresses taken up by the entire bearing structure which are liable to cause quantitative distortions distorting the information supplied by the currently known methods of evaluation.  
         [0057]    In an example of the application illustrated in FIG. 6, the stress sensor designed generally by reference  40 , is of a fluid compression chamber type. In this type of embodiment, sensor  40  includes a bearing cap  41  which is axially and angularly integral with rod  25 , being placed between a bearing head  42  integral with rod  25  and body  21 . Cap  41 , in its annular transversal face opposite end  26 , establishes an annular compression chamber  43  which, with interposed seals  44 , fits over annular piston  45  supported by support body  46  linked with attaching body  21 , for instance by being made integral with spherical bearing  35 . Preferably, the axial link between cap  41  and annular piston  45  is provided by means of socket  47  linked with the cap and bearing under an annular edge  48  presented by piston  45 .  
         [0058]    The assembly as described above forms chamber  43 , referred to as blind in that it has neither an inlet orifice nor an outlet orifice and is completely full of a fluid, such as hydraulic oil, the pressure increase of which can be evaluated by means of measurement linked with the means of remote transmission  50  of the observed pressure variation.  
         [0059]    In the situation described above, corresponding to a lifting function, the load transferred onto shoulders  31  of head  30  solicits rod  25  in the direction of arrow f 2  so that head  42  bears on cap  41 , which tends to engage annular piston  45  even further. This results in the tendency to reduce the volume in annular chamber  43  and consequently, raise the pressure of the hydraulic fluid which is transmitted, for instance by means  50 , to a centralizing device available to the operator in charge of the maneuver in cab  4  of machine  1 .  
         [0060]    In the previously described examples, stress sensor  40  conforming to the invention is implemented on a lifting device forming an attaching lock for a container lifting-handling machine lifting beam. However, in conformity with the invention, stress sensor  40  can be placed on any other type of lifting device for attaching to any load suspended from a handling machine. Accounting, FIG. 7 is another example of the implementation of stress sensor  40  on a lifting device, generally illustrated by reference  55 , forming a sheave lifting hook for a handling crane. Lifting device  55  then includes an attaching body  56  equipped with a sheave system  57 . In addition, the attaching body  56  is equipped with an attaching device  58  having a handling hook  59 .  
         [0061]    As shown more specifically in FIG. 8, attaching body  56  has axial guiding and immobilization means  60 , as well as rotation guiding means  61  formed by a spherical bearing surface in the illustration shown. The attaching device  58 , in the extension of hook  59 , has a rod  62  passing through attaching body  56  and a stress sensor  40  conforming with the invention.  
         [0062]    Rod  62  is thus maintained by immobilization and guide facilities  60  and opposite hook  59  has a bearing head  63  resting on cap  41  of stress sensor  40 , which also has a structure similar to that described in conjunction with FIG. 6. Also, it should be noted that bearing cap  41  and support  46  are both transversed by bore  64  designed to receive suspension rod  62  of attaching device  58 . Note that bore  64  and compression chamber  43  are more or less coaxial.  
         [0063]    In the example given, annular chamber  43  is defined by an annular groove provided in the bearing cap in which the piston defined by support body  46  is engaged. However, according to the invention, annular chamber  43  could be defined by an annular groove in support body  46  in which a piston defined by bearing cap  41  could be engaged.  
         [0064]    Furthermore, note that according to the invention, the compression chamber is not necessarily annular. Accordingly, in a variant not shown here, stress sensor  40  could have a multitude of compression chambers communicating with one another and set out about bore  64  receiving suspension rod  62  of attaching device  58 . Accordingly, stress sensor  40  could have three cylindrical compression chambers arranged at 120° about bore axis  64 .  
         [0065]    Obviously, any other configuration could be used depending upon the conditions for the implementation of the stress sensor conforming to the invention.  
         [0066]    According to the example given in FIG. 7, stress sensor  40  is implemented on a lifting hook equipped with a sheave device  57 . Naturally stress sensor  40  can also be implemented on a simple lifting hook system without a sheave device, as illustrated in FIG. 9.  
         [0067]    The invention is not confined to the examples described and shown because various modifications can be made while remaining within this framework.