Abstract:
An adjustable chock for levelling and anchoring a machine to a foundation. The chock comprises a base element, a centre element and a spherical washer (comprising either a concave or convex surface), each is rotationally symmetric about a centre axis. The centre element is axially translational relative to the base element. The base element or the centre element includes a mating surface (being the other of concave or convex) for receiving the spherical washer. The chock has a centre through hole for receiving an anchor bolt. The base element comprises an hydraulic connection point and a channel for hydraulic fluid. The channel is in connection with a chamber enclosed between surfaces of the centre element and the base element, wherein in use, filling the chamber with hydraulic fluid exerts an axial pressure on the centre element, causing an axial translation of the centre element relative to the base element.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a National Stage Application claiming the benefit of International Application Number PCT/EP2013/061493 filed on 4 Jun. 2013 (Jun. 4, 2013), which claims the benefit of European Patent Application Serial Number PCT/EP2012/060991 filed on 11 Jun. 2012 (Jun. 11, 2012), both of which are incorporated herein by reference in their entireties. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a height-adjustable chock for anchoring and levelling a heavy machine on a foundation. 
       BACKGROUND TO THE INVENTION 
       [0003]    An example of such a device is disclosed in EP 0316283. The device comprises an annular base element having an internal thread, which receives a centre element, part of which is provided with an external thread. The height of the device is therefore adjustable by screwing the centre element relative to the base element. The centre element has a concave top surface, which supports a washer with a convex bottom surface. In use of the device, part of a heavy machine rests on the washer, whereby angular misalignments are accommodated via the convex and concave mating surfaces of the device. Furthermore, the washer and the centre element comprise a through hole, so that when the device has been adjusted to the required height, the machine part can be bolted to the foundation. 
         [0004]    There is still room for improvement. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention resides in an adjustable chock for levelling and anchoring a machine to a foundation. The chock comprises a base element, a centre element and a spherical washer, each of which is rotationally symmetric about a centre axis, whereby the centre element is axially translational relative to the base element; the spherical washer comprises a surface which is one of concave or convex; the base element or the centre element comprises a mating surface for receiving the spherical washer, where the mating surface is the other of concave or convex. The chock further has a centre through hole for receiving an anchor bolt. According to the invention, the base element comprises an hydraulic connection point and a channel for a hydraulic fluid. The channel is in connection with a chamber enclosed between surfaces of the centre element and of the base element such that in use of the chock, filling the chamber with hydraulic fluid causes an axial translation of the centre element relative to the base element. 
         [0006]    In a further development of the invention, the chock comprises a mechanical stop for limiting the axial translation of the centre element relative to the base element and for setting a maximum adjustment height of the chock. 
         [0007]    A chock according to the invention therefore provides a safe and reliable means for the support, height adjustment and anchoring of a heavy machine part. Other advantages of the present invention will become evident from the detailed description and drawings. 
     
    
     
       DESCRIPTION OF THE FIGURES 
         [0008]    The invention will be described with reference to the attached drawings in which: 
           [0009]      FIG. 1   a  shows a cross-sectional view of a first embodiment of a chock according to the invention, in a first position; 
           [0010]      FIG. 1   b  shows a cross-sectional view of the chock of Fig. la, in a second position; 
           [0011]      FIGS. 2-4  respectively show cross-sectional views of a second, a third and a fourth embodiment of a chock according to the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    A first embodiment of the inventive chock is depicted in  FIGS. 1   a  and  1   b.  In  FIG. 1   a  the chock is depicted at its lowest height level; in  FIG. 1   b,  the chock is shown at a maximum height adjustment level. The chock is intended for use in combination with several other chocks for supporting and anchoring a heavy piece of machinery, such as a main propulsion engine on board a marine vessel. In such applications, it is vital the engine is as level as possible, to ensure proper alignment with the vessel&#39;s propeller shaft. Once level, the engine must then be firmly secured to a foundation. 
         [0013]    The chock comprises a base element  110 , a centre element  120  and a spherical washer  130 , each of which has rotational symmetry with respect to a centre axis  105  of the chock. In this embodiment, the spherical washer  130  has a lower surface that is convex in shape, which rests on an upper mating surface of the centre element  120 , which mating surface is concave in shape. The concave/convex mating surfaces accommodate up to approximately  4  degrees of angular difference between e.g. the engine bed and the foundation. To ensure that the mounting plane of the engine is perfectly level, each chock is preferably adjustable in height. The centre element  120  is therefore axially translational relative to the base element  110  along the axis  105 . 
         [0014]    In conventional chocks, the centre element has a threaded connection with the base element, and height is adjusted by screwing the centre element using a manual tool. Depending on the magnitude of the load which the chock must support, manual adjustment may be very difficult. 
         [0015]    In a chock according to the invention, the centre element  120  is adjusted in height relative to the base element  110  via hydraulic means. The centre element is arranged on top of the base element, and fits into the base element. The centre element  120  and the base element  110  are shaped such that a first axial sliding interface is formed between a first cylindrical surface  111  of the base element and an overlapping first cylindrical surface  121  of the centre element. A second axial sliding interface is formed between a second cylindrical surface  112  of the base element and an overlapping second cylindrical surface  122  of the centre element. The first cylindrical surfaces  111 ,  121  of the first sliding interface have a smaller diameter than the second cylindrical surfaces  112 ,  122  of the second sliding interface. Consequently, the base element has a transitional surface  113  between its first and second sliding surfaces  111 ,  112 , and the centre element  120  comprises a transitional surface  123  between its first and second cylindrical surfaces  121 ,  122 . Suitably, a first seal (not shown) is provided between the first cylindrical surfaces  111 ,  121  of the base element  110  and of the centre element  120 , and a second seal (not shown) is provided between the second cylindrical surfaces  112 ,  122  of the base element  110  and of the centre element  120 . Thus, a sealed chamber  160  is defined between the transitional surface  113  of the base element, the transitional surface  123  of the centre element and the first and second sliding interfaces. 
         [0016]    The base element  110  is further provided with a hydraulic connection point  115  at its outermost cylindrical surface. In addition, the base element has a channel  117  for hydraulic fluid, which channel is in connection with the chamber  160 . Thus, when hydraulic fluid is pumped into the chamber  160 , a pressure is exerted on the transitional surface  123  of the centre element, causing it to be raised, as shown in  FIG. 1   b.    
         [0017]    In the depicted embodiment, the first and second cylindrical surfaces of the base element are respectively formed by an inner side wall  111  and an outer side wall  112  of an annular recess. Correspondingly, the first and second cylindrical surfaces of the centre element are formed by an inner side wall  121  and an outer side wall  122  of an annular protrusion  125  that fits into the annular recess. Suitably, the inner side wall of the protrusion  125  has a first groove  126  for receiving the first hydraulic seal (not shown). Similarly, the outer side wall of the protrusion  125  has a second groove  127  for receiving a second hydraulic seal (not shown). 
         [0018]    To prevent the centre element from flying off, in the event that excessive hydraulic pressure is applied, the chock is provided with a mechanical height limiter. In this embodiment, the height limiter  140  is formed by a bushing, which is arranged within a bore of the centre element  120  and within a bore of the base element  110 . The bushing has first section  141  and a second section  142 , whereby the second section  142  has a larger external diameter than the first section. At an upper end of the first section  141 , the height limiter is coupled to the bore of the centre element  120  by means of a threaded connection  145  or other suitable form of connection. Thus, when hydraulic pressure builds up in the chamber  160 , both the centre element  120  and the height limiter  140  move upwards relative to the base element  110 . The bore of the base element  110  has an upper portion  118  and a lower portion  119 . The upper portion has an internal diameter that matches the external diameter of the first section  141  of the height limiter, and the lower portion  119  has an internal diameter that matches the external diameter of the second section  142  of the height limiter  140 . The maximum adjustment height of the chock  100  is therefore reached when the second section  142  of the height limiter  140  hits the upper portion  118  of the base element bore. Safety is thereby ensured. 
         [0019]    When the centre element has been adjusted to the desired height, it can be secured at this height. In the depicted embodiment, the chock further comprises a locknut  150 . Suitably, an outermost cylindrical surface of the centre element  120  is provided with an external thread that engages with an internal thread of the locknut. The locknut therefore moves with the centre element when hydraulic fluid is pumped into the chamber  160 . Preferably, the external thread on the centre element extends along a greater axial distance than the internal thread of the nut. When the desired height has been reached, the locknut  150  can therefore be screwed downwards until a bottom surface of the locknut hits a top surface of the base element, as shown in  FIG. 1   b.  The hydraulic pressure can then be removed, and the locknut  150  takes over the forces from the supported load. 
         [0020]    Finally, an anchor bolt is inserted through a central opening in the spherical washer  130  and through a bore of the height limiter  140 . 
         [0021]    Several designs are possible within the scope of the current invention. For example, a second embodiment of an inventive chock is depicted in  FIG. 2 . The chock comprises a base element  210 , a centre element  220  and a spherical washer  230 . The spherical washer  230  has a concave upper surface in this embodiment, and the base element  220  rests on the washer and is provided with a convex mating surface. The centre element has a top plate  225  for supporting the load. 
         [0022]    The chock again comprises a first axial sliding interface between opposing cylindrical surfaces of the base element  210  and the centre element  220 . A first seal  171 , such as an o-ring, is provided at the first interface. The chock further comprises a second axial sliding interface between opposing cylindrical surfaces of the base element  210  and the centre element  220 . A second seal  172  is provided at the second interface. A chamber  260  for hydraulic fluid is thus defined by the first and second sliding interfaces and lower and upper surfaces of the centre element  230  and base element  210  respectively. The chamber  260  is connected to hydraulic connection point  215  on the outermost cylindrical surface of the base element via a channel  217 . 
         [0023]    In this embodiment, the bore of the centre element  220  extends over the full axial height of the chock, and serves as the opening for receiving the anchor bolt. At a lowermost portion of the centre element  230 , a nut  240  is coupled to the centre element. The base element  210  again has a bore with a large diameter section  219  and a small diameter section  218 , above the large-diameter section. The nut  240  therefore serves as the mechanical height limiter, which prevents the centre element  220  from being raised further when the nut  240  hits the small-diameter section  218  of the base element bore. 
         [0024]    The chock of the second embodiment is also provided with a locknut for securing the chock at a desired height level. In this embodiment, an outermost cylindrical surface of the base element  210  is provided with an external thread  212 , which engages the internal thread of the locknut  250 . When the centre element  220  has been set to the desired height, by pumping hydraulic fluid into the chamber  260 , the chock is secured at this height by screwing the locknut  250  upwards until it hits an underside of the top plate  225  of the centre element. 
         [0025]    A third embodiment of a chock according to the invention is depicted in  FIG. 3 . As before, the chock comprises a chamber  360  enclosed by first and second axial sliding interfaces between opposing first and second cylindrical surfaces of the base element  310  and the centre element  320 . The spherical washer  330  has a convex upper surface on which a concave mating surface of the base element is received. The centre element  220  has a top plate  225  for supporting the load. 
         [0026]    In this embodiment, the adjustment height of the chock is limited by at least one first bolt  340  and the chock is secured at the desired height by at least one second bolt  350 . The top plate comprises at least one threaded hole for receiving the at least one first bolt  340 , such that an end of the bolt shank  342  is connected to the centre element  320 . The base element  310  comprises a flange part  315 , which comprises a though hole that is arranged axially opposite from the threaded hole  328  in the top plate  325  of the centre element. The bolt shank  342  of the first bolt  340  is inserted through the flange hole and can slide axially within this through hole, as the height of the centre element relative to the base element changes. A maximum height adjustment level is reached when the bolt head  345  hits an underside of the flange  315  of the base element, as depicted in  FIG. 3 . Preferably, the height limitation means comprises a plurality of first bolts  340 . 
         [0027]    For locking the centre element at the desired height level, the flange part  315  of the base element  310  comprises a threaded through hole for the at least one second bolt  350 . Preferably, a plurality of second bolts and corresponding threaded through holes are provided. When the desired height level is reached, each second bolt is screwed upwards until a base of the bolt shank makes contact with an underside of the top plate  225 . Thus, the plurality of second bolts  350  take over the forces from the supported load and the hydraulic pressure can be removed. The chock is then anchored to the foundation using an anchor bolt. 
         [0028]    It is also possible to lock the centre element at the desired height hydraulically, by using a pressure greater than the pressure needed for height adjustment and which is sufficient to withstand the forces from the anchor bolt. 
         [0029]      FIG. 4  shows an example of a fourth embodiment of a chock according to the invention, which is provided only with mechanical height limitation  440  and not with mechanical locking means. The height limiter is formed by a stop plate  440 . The stop plate has a cylindrical inner surface, provided with an internal thread, which engages with an external thread on an outermost cylindrical surface of the base element  410 . The stop plate has a flange part  415 , perpendicular to the cylindrical surface of the stop plate, which overlap an axially oriented top surface  425  of the centre element  420 . In the depicted embodiment, the stop plate is screwed upwards to a maximum permissible height, before hydraulic fluid is pumped into the chock&#39;s hydraulic fluid chamber. In a further example, the stop plate has a greater axial length, whereby an underside of the flange part  445  is arranged above the axially oriented top surface  425  of the centre element. It may then be unnecessary for further adjustment of the stop plate  440 . 
         [0030]    A number of aspects/embodiments of the invention have been described. It is to be understood that each aspect/embodiment may be combined with any other aspect/embodiment. Moreover the invention is not restricted to the described embodiments, but may be varied within the scope of the accompanying patent claims.