Patent Publication Number: US-2002001517-A1

Title: Arrangement at a lifting hook

Description:
[0001] This invention regards a hook arrangement for connecting heavy packages to a hook or other lifting equipment.  
       [0002] When connecting up heavy packages, use is often made of holding chains with a through bolt. In order to achieve articulated, mechanical linkage in the case of this type of coupling, it is necessary to use a single bolt/shaft or possibly several bolts/shafts arranged along a common centre line. Each of the elements forming part of the coupling is of such a size so as to necessitate the use of a separate auxiliary crane in order to position the coupling elements correctly in relation to each other. Then striking tools or hydraulic tools must be used in order to guide the bolt/shaft into the through openings, between which openings and bolt there is often a relatively tight fit. The time taken to connect up heavy lifting gear constitutes a substantial part of the total lifting time for heavy packages, thereby contributing a considerable share of the lifting costs.  
       [0003] The object of the invention is to remedy the negative aspects of the prior art.  
       [0004] The object is achieved in accordance with the invention by the characteristics stated in the description given below and in the following claims.  
       [0005] A rapid coupling is fitted to the load attachment point of a crane or item of lifting equipment (hereinafter termed “crane”), which rapid coupling is designed to be able to couple the crane to a load to be lifted, essentially without the use of auxiliary tools. The rapid coupling comprises one or more hook-like lifting elements (hereinafter termed “hook”) and a yoke-like fastening device (hereinafter termed “yoke”) provided with axle journals that match the hooks. The yoke is designed to be fitted to the normal attachment fittings of the lifting tool while the hooks may be attached to the crane by conventional coupling elements.  
       [0006] On coupling a load to the crane, the hook(s) is/are inserted under the shaft(s) of the yoke and then lifted up so that the hook(s) abut(s) and partially enclose(s) the shaft(s). An actuator-operated lock, e.g. a hydraulically operated locking plate, is swung from a retracted, inactive position to an operative position in which the locking plate prevents the shaft from being pushed out of the hook. On uncoupling, the locking plate is swung into its inactive position, whereupon the hook(s) is/are lowered and pushed out of the shaft(s). 
     
    
    
     [0007] The following describes a non-limiting example of a preferred embodiment that is illustrated in the accompanying drawings, in which:  
     [0008]FIG. 1 shows a lifting tool connected to a crane via a rapid coupling;  
     [0009]FIG. 2 is an enlarged side view of the rapid coupling in  
     [0010]FIG. 1 in an uncoupled position;  
     [0011]FIG. 3 is an enlarged side view of the rapid coupling in  
     [0012]FIG. 1 in a coupled position;  
     [0013]FIG. 4 is a front view of the hook of FIG. 3;  
     [0014]FIG. 5 shows a section through the hook of FIG. 4;  
     [0015]FIG. 6 is a side view of the yoke of FIG. 2;  
     [0016]FIG. 7 is a front view of the yoke of FIG. 2; and  
     [0017]FIG. 8 is a front view of the rapid coupling. 
    
    
     [0018] In the drawings, reference number  1  denotes a multiarticulated crane coupled via a rapid coupling  2  according to the invention to a lifting tool  3  here shown in the form of a plate yoke for lifting of a load  4 . In a preferred embodiment, the rapid coupling  2  is provided with two hooks  6  rotatably connected in the load attachment point  5  of the crane  1 , see FIG. 2. In this figure, the locking plate  7  of the hook  6  has been swung in about a swivel axle  22  to its inactive position by an actuator  8 , e.g. in the form of a hydraulic cylinder, by means of hydraulic tubes not shown. The other main part of the rapid coupling  2  is made up of a yoke  9  hinged to the ordinary attachment fittings  10  of the lifting tool  3  by two fastening bolts  11 ,  11 ′. The fastening bolts  11 ,  11 ′ are secured against falling out by means of cotter pins (not shown). In this preferred embodiment, the yoke  9  is equipped with a through shaft  12 , see FIG. 7, both projecting end portions of which are provided with a flange  13 ,  13 ′. The mid section  14  of the yoke  9  is constructed as a welded plate construction and dimensioned so as to transfer the load from four hanging hinge lugs  15  to the shaft  12 , see FIG. 6. The free portions of the shaft  12  between the mid section  14  and the flanges  13 ,  13 ′ form an abutment area  16 ,  16 ′ against the load bearing area  17  of the hook, see FIG. 5.  
     [0019] In the embodiment shown, see FIGS. 4 and 5, the hook  6  is constructed as a welded, hollow plate construction. Through openings  19 ,  19 ′ are provided at the upper end portions of the lateral plates  18 ,  18 ′ of the hook  6 , which openings are adapted to the load attachment point  5  of the crane  1 . The lower end portion of the lateral plates  18 ,  18 ′ is designed as a hook in order to be inserted radially across the load bearing area  16 ,  16 ′ of the shaft  12 .  
     [0020] An intermediate plate  20  is shaped according to the contours of the lateral plates  18 ,  18 ′, forming a cavity in conjunction with the lateral plates  18 ,  18 ′. The intermediate plate  20  is provided with an opening  21  through which the locking plate  7  swings between its retracted, inactive position and its swung-out locking position. The locking plate  7  is rotatably attached to the lateral plates  18 ,  18 ′ of the hook  6  about the swivel axle  22 . The actuator  8  is hinged to said lateral plates  18 ,  18 ′ and the locking plate  7  by means of linkages that are known per se.  
     [0021] On coupling up the hooks  6  of the rapid coupling  2  and the yoke  9 , the hooks  6 , in which the locking plate  7  is in the swung-in, inactive position, are guided in under the shaft  12  of the yoke  9 . The hooks  6  are lifted such that the load bearing area  17  of the hooks  6  abuts the load bearing area  16 ,  16 ′ of the shaft  12 . The locking plate  7  is rotated about its swing axle  22  to a swung-out locking position, see FIG. 3, which prevents the shaft  12  from being pushed out of the hooks  6 . See FIGS. 3 and 8.  
     [0022] The coupling of a lifting tool  3  to the crane  1  is thus performed in a simple, safe and reasonable manner without the need for additional auxiliary lifting equipment, the crane  1  itself, by means of devices in accordance with the invention, being designed to be used for coupling and uncoupling lifting tools  3 .