Abstract:
Provided is an apparatus for reducing the pitching and rolling motion of a vessel, the apparatus including a plurality of buoyancy members spaced apart from each other and vertically slidably mounted on a vessel, a plurality of hydraulic cylinders that are connected to the upper end portions of the respective buoyancy members and receive the locomotive power of the buoyancy members that rise from waves, and a hydraulic connection line provided in such a manner that the hydraulic pressures of the hydraulic cylinders are interconnected, so that the hydraulic pressures, which are generated from the rise of the hydraulic cylinders due to the rise of the buoyancy members located at the peaks of the waves, can be supplied to the hydraulic cylinders located at the troughs of the waves to cause the buoyancy members to fall, thereby increasing the buoyancy of the vessel and restraining the pitching and rolling thereof.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an apparatus for reducing pitching and rolling motions of a vessel, and more particularly, to an apparatus for reducing pitching and rolling motions of a vessel caused by waves. 
         [0003]    2. Description of the Related Art 
         [0004]    Generally, when a vessel that travels over sea sails across or lies in a billowy sea area, the vessel is subjected to movement such as pitching-a vertical motion and rolling-a lateral motion, so that there is a risk of the occurrence of a safety accident on the passengers because they lose their balances, and if passengers who have no or little experience in boarding are continuously subjected to repetitive shaking of a vessel, they may suffer from seasickness accompanied by a headache and vomiting, putting a blight on their voyage. Further, it is difficult to stably carry out the work of making repairs or moving an object. 
         [0005]    In order to reduce such shaking of a vessel, a bilge keel has been conventionally used. The bilge keel is a fin-type stabilizing device that is fitted on each side of a vessel so as to push out water in opposite direction from the center of the vessel, using the fin-type area, thereby reducing the rolling of the vessel. 
         [0006]    However, since the conventional bilge keel mainly carries out restricting only the rolling motion of the vessel caused by waves, such restriction in motion is not sufficient to considerably reduce the shaking of a vessel in such a manner as to make passengers feel pleasant, nor restricts a pitching motion of a vessel. 
       SUMMARY OF THE INVENTION 
     Technical Problem 
       [0007]    An object of the present invention is to provide an apparatus for reducing pitching and rolling motions of a vessel caused by waves in order to make passengers feel pleasant. 
       Solution to Problem 
       [0008]    The present invention provides an apparatus for reducing pitching and rolling motions of a vessel according to an aspect of the present invention. The apparatus includes: a plurality of buoyant members disposed in such a manner as to be vertically slidable; a plurality of hydraulic cylinders each connected to an upper end of the buoyant member to receive a moving force of the buoyant member that ascends with the action of waves; and a hydraulic connection line unit connected in such a manner that hydraulic pressures of the hydraulic cylinders communicate with each other such that hydraulic pressure that is generated concurrently with a rise of the hydraulic cylinder when the buoyant member located at hill of a wave ascends is supplied to the hydraulic cylinder located at dale of a wave so as to lower the buoyant member to cause the buoyant force of the vessel to increase, thereby restricting the shaking of the vessel. 
         [0009]    The buoyant member may be disposed at stem or stern of the vessel. 
         [0010]    The buoyant member may be oppositely disposed one for each side of the vessel. 
         [0011]    The buoyant member may be disposed at the bottom of the vessel. 
         [0012]    The apparatus may include a damping valve that is disposed between the hydraulic cylinders and the hydraulic connection line unit to perform a control operation such that high hydraulic pressure of the hydraulic cylinder, which is generated concurrently with a rise of the buoyant member by means of the action of waves, is allowed to pass through the hydraulic cylinders and hydraulic connection line unit, and hydraulic pressure generated by a change in load of an object including goods shipped in a vessel, the magnitude of load being smaller than the buoyant force of a vessel, is blocked from passing through the hydraulic cylinders and hydraulic connection line unit. 
         [0013]    Here, the damping valve may include: a barrel-type body section, opposite ends of which are coupled to the hydraulic cylinders and hydraulic connection line unit in an inter-communication manner, and having first and second engagement parts in an inner side thereof; a first control plate installed in such a manner as to be vertically slidable between the bottom of the body section and the second engagement part and having a central hole; a first elastic member installed between the first control plate and the bottom of the body section to support the first control plate; a control rod installed in such a manner as to be vertically slidable through the first engagement part and having at a lower end thereof a second control plate opposite to the first control plate; and a second elastic member installed between the second control plate and the first engagement part in such a manner as to be inserted around the control rod to allow the second control plate to block the central hole of the first control plate. Further, the elastic force of the second elastic member may be greater than that of the first elastic member. 
         [0014]    The apparatus may further include a barrel-type guide member through which the buoyant member is guided to vertically move in an inserted state, and a third elastic member disposed inside of the guide member to prevent the buoyant member that is ascending from colliding with the guide member. 
       Advantageous Effects of Invention 
       [0015]    According to the apparatus for reducing pitching and rolling motions of a vessel, the plurality of buoyant members are disposed such that the hydraulic cylinders connected with each other via the hydraulic connection line unit are respectively connected to the upper ends of the buoyant members. This causes that hydraulic pressure that is generated concurrently with a rise of the hydraulic cylinder when the buoyant member located at hill of a wave ascends is supplied to the hydraulic cylinder located at dale of a wave so as to lower the buoyant member to cause the buoyant force to increase, thereby restricting the shaking of the vessel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a cross-sectional view showing the schematic construction of an apparatus for reducing pitching and rolling motions of a vessel according to an embodiment of the present invention. 
           [0017]      FIG. 2  is a plan view showing the state of the apparatus for reducing pitching and rolling motions of a vessel being installed. 
           [0018]      FIG. 3  is a plan view showing an apparatus for reducing pitching and rolling motions of a vessel according to another embodiment. 
           [0019]      FIG. 4  is a side view showing an apparatus for reducing pitching and rolling motions of a vessel according to still another embodiment. 
           [0020]      FIG. 5  is an enlarged cross-sectional view showing a damping device shown in  FIG. 1 . 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0021]    Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
         [0022]      FIG. 1  is a cross-sectional view showing the schematic construction of an apparatus for reducing pitching and rolling motions of a vessel according to an embodiment of the present invention,  FIG. 2  is a plan view showing the state of the apparatus for reducing pitching and rolling motions of a vessel being installed, and  FIG. 3  is a plan view showing an apparatus for reducing pitching and rolling motions of a vessel according to another embodiment. Referring to  FIGS. 1 to 3 , the apparatus for reducing pitching and rolling motions of a vessel includes buoyant members  100 , hydraulic cylinders  200 , and a hydraulic connection line unit  300 . 
         [0023]    The plurality of buoyant members  100  is disposed in a vessel so as to regulate the buoyant force of the vessel  10  in response to waves. The buoyant members  100  are oppositely arranged in a spaced manner on opposite sides of the vessel  10 . The buoyant members are installed at the outside or inside of the vessel  10  in such a manner as to be vertically slidable such that they rise and fall as the waves roll. Thus, upon surging of waves upon the vessel  10 , as the buoyant members  100  located at the hills of waves ascend with the buoyant force of waves, the buoyant force of the vessel  10  is reduced as much. Here, if the buoyant members  100  are installed at the inside of the vessel  10 , the portions where the buoyant members are installed are made open such that the buoyant members can come into contact with the waves therethrough. 
         [0024]    Referring to  FIG. 3 , the buoyant members  100  may be arranged in a spaced manner at the inside or outside of stem and stern of a vessel. Further, as shown in  FIG. 4 , the buoyant members  100  may be arranged in a spaced manner at the inside of the bottom of the vessel  10 . Alternatively, the buoyant members  100  may be arranged in a spaced manner along an inner or outer circumference of the vessel  10 . Herein, if the buoyant members  100  are also installed at the inside of the vessel  10 , the portions where the buoyant members  100  are installed are made open such that the buoyant members can come into contact with the waves therethrough. 
         [0025]    The buoyant member  100  may be formed of a closed barrel-type member having a cavity therein, which is made of but is not limited to Styrofoam. The buoyant member may also be made of any material so long as the material has improved buoyancy to ascend a vessel on the sea. Here, if the buoyant member  100  is formed of a closed barrel-type member having a cavity therein, it may be made of metal or plastic material. While the buoyant member  100  is shaped like a rectangle according to an embodiment, the buoyant member is not limited to that shape, but may be shaped like a circle or a polygon other than a rectangle. 
         [0026]    The buoyant member  100  may be vertically movably inserted into a guide member  110  coupled to the outside of the vessel  10 , wherein the guide member is open downwards. If the buoyant member  100  is inserted into and installed to the guide member  110 , the buoyant member  100  can receive the buoyant force of waves only in the vertical direction, so that it can ascend in a stable manner. The guide member  110  may be provided at an inner upper surface thereof with a third elastic member  120 . That is, the third elastic member  120  is disposed between the inner upper surface of the guide member  110  and the upper end of the buoyant member  100  in order to prevent the buoyant member  100  that is ascending from colliding with the guide member  110 . Here, while the third elastic member  120  has been illustrated to be composed of a spring, the third elastic member is not limited to the spring, but may selectively use other elastic member that is elastic. 
         [0027]    The hydraulic cylinder  200  receives a moving force of the buoyant member  100  that ascends with the action of waves. The hydraulic cylinders  200  each are connected to the upper ends of the respective buoyant members  100 . That is, a rod end of the hydraulic cylinder  200  is connected to the upper end of the buoyant member  100  so that when the buoyant member  100  ascends with the action of waves, the hydraulic cylinder  200  receives the ascending force of the buoyant member  100  and then a piston thereof (not shown) is pushed up to increase an internal hydraulic pressure. 
         [0028]    The hydraulic connection line unit  300  is configured to transmit high hydraulic pressure, generated by the hydraulic cylinder  200  receiving the ascending force of the buoyant member  100  when the buoyant member  100  ascends by the action of waves, to another hydraulic cylinder  200 , resulting in descent of the buoyant member  100 . That is, the hydraulic connection line unit  300  is configured such that high hydraulic pressure that is generated concurrently with the piston of the hydraulic cylinder  200  being pushed-up when the buoyant member  100  located at hill of a wave ascends is supplied to the hydraulic cylinder  200  located at dale of a wave so as to lower the buoyant member  100  to cause the buoyant force of a vessel  10  to increase, thereby restricting the shaking of the vessel  10 . 
         [0029]    The hydraulic connection line unit  300  is a single pipe member connecting the respective hydraulic cylinders and through which hydraulic pressure is guided and carried via the same line. Thus, the hydraulic cylinder  200  that is located at hill of a wave so that it is actuated concurrently with ascent of the buoyant member  100  increases the hydraulic pressure, which in turn is supplied to another hydraulic cylinder  200 , i.e. the hydraulic cylinder  200  that is located at dale of a wave, via the hydraulic connection line unit  300 , allowing the buoyant force of the vessel  100  to increase while lowering the buoyant member  100 , thereby keeping the vessel  10  in a horizontal state. 
         [0030]    Further, a damping valve  400  may be installed between the hydraulic connection line unit  300  and respective hydraulic cylinder  200 . The damping valve  400  is configured such that only the hydraulic pressure generated by the buoyant member  100  is allowed to communicate with another hydraulic cylinder  200  via the hydraulic connection line unit  300 , and lower hydraulic pressure generated by an external force caused by such as goods shipped in the vessel  10  is blocked from circulating via the hydraulic connection line unit  300 , thereby preventing the shaking of a vessel  10  from being amplified. That is, when high hydraulic pressure is introduced towards the hydraulic cylinder  200  along the hydraulic connection line unit  300 , the damping valve  400  is opened due to a lower pressure difference and allows the high hydraulic pressure to pass therethrough. 
         [0031]    Referring to  FIG. 5 , the damping valve  400  includes a body section  410 , a first control plate  420 , a first elastic member  430 , a control rod  440 , and a second elastic member  440 . 
         [0032]    The body section  410  is a barrel-type member which is connected with the hydraulic cylinder  200  and the hydraulic connection line unit  300 , respectively, in a communication manner. Referring to  FIG. 1 , an upper end of the body section  410  is communication-connected with the hydraulic connection line unit  300 , and a lower end of the body section is communication-connected with the hydraulic cylinder  200 . The body section  410  is provided at an inner upper end thereof with a first engagement part  411  through which the control rod  440  is vertically guided. The body section  410  is also provided at an inner lower end thereof with a second engagement part  412  on which the first control plate  420  latch such that the first control plate cannot be further moved upwards. 
         [0033]    The first control plate  420  controls an inflow of hydraulic pressure into the hydraulic cylinder  200  via the hydraulic connection line unit  300 . The first control plate  420  is vertically slidably installed between the bottom of the body section  410  and the second engagement part  412 . Here, the first control plate  420  is provided with a central hole (not shown) through which hydraulic pressure flows. 
         [0034]    The first elastic member  430  serves to allow the internal hydraulic pressure of the hydraulic connection line unit  300  to be introduced into the hydraulic cylinder  200  only when the hydraulic pressure is of high pressure generated by waves. That is, the first elastic member  430  is installed between the first control plate  420  and the bottom of the body section  410  so as to support the first control plate  420 . Thus, the first control plate  420  is moved downwards by the first elastic member  430  only when the internal hydraulic pressure of the hydraulic connection line unit  300  becomes higher than the elastic force of the first elastic member  430 , thereby enabling the internal hydraulic pressure of the hydraulic connection line unit  300  to be introduced into the hydraulic cylinder  200 . 
         [0035]    The control rod  440  controls an inflow of internal hydraulic pressure of the hydraulic cylinder  200  into the hydraulic connection line unit  300 . The control rod  440  is vertically slidably installed through the first engagement part  411 . The control rod  440  is provided at a lower end thereof with a second control plate  441  that is planar and is provided opposite the first control plate  420 . Here, the second control plate  441  serves to open and close the central hole of the first control plate  420  as the control rod  440  moves up and down. 
         [0036]    The second elastic member  450  allows the internal hydraulic pressure of the hydraulic cylinder  200  to be introduced into the hydraulic connection line unit  300  only when the internal hydraulic pressure is of high pressure generated by waves. That is, the second elastic member  450  is located between the second control plate  441  and the first engagement part  411  in such a manner as to be inserted around the control rod  440 , thereby supporting the second control plate  441 . Thus, the second control plate  441  of the control rod  440  first comes into close contact with the first control plate  420  by means of the second elastic member  430 , blocking the central hole, and then is moved upwards to open the central hole only when the internal hydraulic pressure of the hydraulic cylinder  200  becomes higher than the elastic force of the second elastic member  450 , thereby allowing the internal hydraulic pressure of the hydraulic cylinder  200  to be introduced into the hydraulic connection line unit  300 . 
         [0037]    Here, the damping valve  400  is configured such that the elastic force of the second elastic member  450  is made greater than the elastic force of the first elastic member  430 , in order that hydraulic pressure-circulation between the hydraulic connection line unit  300  and the hydraulic cylinder  200  is carried out only when the hydraulic pressure becomes high pressure generated by waves. 
         [0038]    The operation of the apparatus for reducing pitching and rolling motions of a vessel constructed as previously described will be described with reference to  FIGS. 1 to 5 . 
         [0039]    When waves roll against the vessel  10  floating on the sea, the buoyant member  100  located at hill of a wave ascends with the buoyant force of the waves, and the entire buoyant force of the vessel  10  is reduced as much as the buoyant member  100  ascends. 
         [0040]    Concurrently, the rod of the hydraulic cylinder is pushed up by ascent of the buoyant member  100 , increasing the internal hydraulic pressure of the hydraulic cylinder  200  and thus pushing up the control rod  440  of the damping valve  400 , thereby allowing the hydraulic pressure to be fed and supplied to the hydraulic connection line unit  300 . 
         [0041]    As such, high hydraulic pressure introduced into the hydraulic connection line unit  300  is fed and introduced into a low-pressure region, i.e. the hydraulic cylinder  200  which is located at dale of a wave, while the first control plate  420  of the damping valve  400  is pushed down. Thus, the rod of the hydraulic cylinder  200  is pushed down to move down the buoyant members  100  so as to increase the buoyant force at those portions. 
         [0042]    Like this, the buoyant member  100  located at hill of a wave reduces the buoyant force of a vessel because of its ascent caused by buoyant force, and the buoyant member  100  located at dale of a wave descends while being supplied via the hydraulic connection line unit  300  with high hydraulic pressure generated from the buoyant member  100  located at hill of a wave, increasing the buoyant force of a vessel  10  and therefore reducing the shaking of the vessel  10 . 
         [0043]    As previously set forth, according to the apparatus for reducing pitching and rolling motions of a vessel, the plurality of buoyant members  100  is disposed in the vessel  10  such that the hydraulic cylinders  200  connected with each other via the hydraulic connection line unit  300  are respectively connected to the upper ends of the buoyant members  100 . This causes that hydraulic pressure that is generated concurrently with a rise of the hydraulic cylinder  200  when the buoyant member  100  located at hill of a wave ascends is supplied to the hydraulic cylinder  200  located at dale of a wave so as to lower the buoyant member  100  to cause the buoyant force of the vessel  10  to increase, thereby restricting the shaking of the vessel  10 . 
         [0044]    Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.