Abstract:
A door hinge unit for smoothly opening and closing a door using the fluid resistance force of a fluid comprises: a cylindrical oil container containing a viscous fluid therein and having a fluid transfer groove formed along a circumferential direction at an inner wall of the container; a hinge shaft rotatably supported within the oil container with the same core axis as the oil container and whose at least one end is protruded along an axial direction of the oil container, the hinge shaft having a blade formed at an outer circumferential surface thereof and which is slidingly in contact with the inner wall of the oil container; a barrier formed crossing the inner wall of the oil container and an outer circumference of the hinge shaft and having a penetration fluid passage formed along the circumferential direction; and a restoring spring whose one end is coupled to the oil container and the other end is coupled to the hinge shaft.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
         [0001]    This application is a continuation of pending International Patent Application No. PCT/KR01/01145 filed Jul. 5, 2001, which designates the United States and claims priority of pending Korean Application Nos. 2000/70053, filed Nov. 23, 2000 and 2001/39872 filed Jul. 4, 2001.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to a door hinge unit for smoothly opening and closing a door using fluid resistance force of a viscous fluid, and more particularly, to a door hinge unit which is capable of controlling speed of the door according to an opening position of the door, and has a fire prevention function therein, and also has a simple structure capable of miniaturizing its size, thereby applying the door hinge unit to all kinds of doors.  
           [0004]    2. Description of the Related Art  
           [0005]    A door hinge functions to support a door and, and at the same time, functions as a rotational shaft of the door. Generally, in addition to the door hinge, a door closer is additionally disposed at a large-sized door such as a front door or a fire door of an apartment building so as to automatically and slowly close the open door.  
           [0006]    The door closer is a device for smoothly performing an opening and closing operation of the door using elastic force of a spring and resistance force of a viscous fluid. One of the most known door closers is a hydraulic cylinder type door closer having a rectangular body in which a hydraulic cylinder and a return spring are mounted, wherein the rectangular body is attached to an upper portion of the door and then fixed through a pair of links to a doorframe. The hydraulic cylinder type door closer automatically closes the door using the elastic restoring force of the spring applied to a piston, and at the same time, smoothly performs the closing operation of the door using the resistance force of the viscous fluid within the hydraulic cylinder.  
           [0007]    However, as described above, since the hydraulic cylinder type door closer is separately disposed at the door, in addition to the door hinge, and then fixedly attached through the links to the doorframe, it is limited in a mounting position. And also appearance beauty is remarkably lowered. Therefore, it is difficult that the door closer is applied to a small-sized door except the large-sized door. Further, since the hydraulic cylinder type door closer has many components and a complicated structure and also a cost of the door closer is high, there is a problem that it takes so much collateral cost when installing the door closer.  
           [0008]    To solve the problem, there has been proposed a door hinge unit in which a blade having a check valve is formed at a hinge shaft and then received in a housing in which high viscous fluid is contained. One of the door hinge units with a door closer function is described in Korean Patent No. 202260, entitled “Automatic door closer unit”.  
           [0009]    As shown in FIG. 1, a conventional door hinge unit has a cup-shaped housing  110  in which the high viscous fluid is contained and of which an upper portion is opened. A barrier  111  having an oil through-path  113  is integrally formed at a side portion of an inner sidewall of the housing. A flow controlling member  115  for controlling flow of oil passing through the oil through-path  113  is screwed to a screw hole  114  that communicates the oil through-path  113  and an outside of the housing.  
           [0010]    A hinge shaft  120  is rotatably disposed in an inner portion of the housing  110 . The housing  110  is formed with a blade  121  that slidably and closely contacted with the inner sidewall of the housing.  
           [0011]    Two oil moving holes  122  are formed at the blade  121  to be apart at a desired distance. A check valve  127  is coupled to a side of the blade  121  using a screw  128  so as to open or close the oil moving holes  122  according to a rotational direction of the door. Further, at a lower portion of the blade  121 , there is formed a stopper receiving groove  123  in which a spring  124  and a stopper  125  are received.  
           [0012]    Meanwhile, a spring receiving groove is formed at a lower portion of the hinge shaft  120  so that a return spring  130  is received therein. One end of the return spring  130  is fixed to the lower portion of the housing  110  and the other end thereof is fixed to an upper sidewall of the spring receiving groove.  
           [0013]    A cover  140  is coupled to an upper open portion of the housing  110  so as to prevent an outflow of the oil. At a center portion of the cover  140 , there is formed a hinge shaft through hole through which an upper end of the hinge shaft  120  is protruded to an upper portion of the cover  140 . And then a door supporting portion  150 , a washer  155  and a doorframe supporting portion  160  are coupled to the upper portion of the cover  140  in order.  
           [0014]    The door supporting portion  150  is provided with a supporting portion  151  and a connecting portion  152  perpendicularly extended from the supporting portion  151  and having a hinge shaft through-hole  153  at a center portion thereof. The door supporting portion  150  is fixed to an upper portion of the cover  140  by a screw. The doorframe supporting portion  160  has the same shape as the door supporting portion  150  and also has a coupling hole  161  having a larger diameter than the hinge shaft through-hole  153  corresponding to the hinge shaft through-hole  153  of the door supporting portion  150 . At an inner circumference of the coupling hole  161 , there is formed an irregular portion.  
           [0015]    A circular wedge  170  is provided at an inner portion of the coupling hole  161  so as to compensate mismatching of the coupling hole  161  due to a position error between the doorframe and the door. At an outer circumference of the circular wedge  170 , there are formed a plurality of coupling protrusions tapered upward and downward. The circular wedge  170  also has a rectangular through hole  171  in which the upper end of the hinge shaft  120  is fixedly inserted.  
           [0016]    According to the conventional door hinge unit, described above, when opening the door, the check valve  127  is also open. The oil in the housing is moved through the oil moving holes  122  formed at the blade as well as the oil through-path  113  formed at the barrier  111 . Therefore, the resistance of the oil with respect to the rotational operation of the blade is reduced. As the result, the door can be rapidly opened. The closing operation of the door is performed using the restoring force of the return spring  130 . When closing the door, the check valve  127  is closed, and the oil moving holes  122  formed at the blade are blocked. Therefore, the oil in the housing is moved through only the oil through-path  113  formed at the barrier  111 . As the result, the closing operation of the door is slowly performed.  
           [0017]    Meanwhile, the stopper  125  functions to stop the door at a predetermined open position, when the door is rotated. In case the stopper  125  is arrived at a hemispheric stopping groove formed at a bottom face of the housing, a hemispheric end of the stopper  125  is inserted into the stopping groove by the elastic force of the spring  124 . Therefore, the door is stopped. In this situation, when external force is applied to the door, the door is further opened or closed.  
           [0018]    However, in the conventional door hinge unit, as described above, since the flow of the oil is decided by only an opening or closing operation of the check valve, it is impossible to variously control speed of the door according to the open position of the door. In order to provide a stopping function at the door, the hemispheric stopping groove and the stopper receiving groove have to be formed at the housing and the blade. Further, separate components such as the stopper and a spring for supporting the spring are needed. Therefore, there is a problem that a structure of the door hinge unit is complicated and also a fabricating cost is increased.  
           [0019]    In addition, since the return spring is disposed at the inner portion of the hinge shaft, an outer diameter of the hinge shaft is increased within a desired extent. Therefore, an entire size of the door hinge unit is increased. It is difficult to reduce a size of an electronic appliance in which the door hinge unit is applied.  
           [0020]    Further, among stairs in an apartment building, there is generally provided a fire prevention function for automatically closing each stair at a desired temperature or more, when a fire breaks out. In case of the conventional door hinge unit, there is other problem that separate fire prevention equipment should be provided.  
         SUMMARY OF THE INVENTION  
         [0021]    Therefore, it is an object of the present invention to provide a door hinge unit that is capable of facilely controlling speed of a door according to an open position of the door.  
           [0022]    It is other object of the present invention to provide a door hinge unit that is capable of performing a sectional stopping function without a separate stopper.  
           [0023]    It is another object of the present invention to provide a door hinge unit that has a fire prevention function therein.  
           [0024]    It is yet another object of the present invention to provide a door hinge unit that is capable of miniaturizing its size and applying to various kinds of doors.  
           [0025]    To achieve one of the aforementioned objects of the present invention, there is provided a door hinge unit comprising an oil container which contains a viscous fluid in an inner sidewall thereof and has a fluid moving groove formed along a circumferential direction at the inner sidewall; a hinge shaft which is rotatably supported in the oil container with the same core axis as the oil container, and of which at least one end is protruded in an axial direction of the oil container, and which has blade formed at an outer circumferential surface thereof, the blade being slidably and closely contacted with the inner sidewall; a barrier which is formed to cross between the inner sidewall of the oil container and the outer circumferential surface of the hinge shaft, and which has a oil through-path formed in the circumferential direction; and a return spring of which one end is coupled to the oil container and the other end is coupled to the hinge shaft.  
           [0026]    Further, a heat detecting member formed of a material having a low melting point is provided at an end of the oil moving groove so as to have an inner sidewall corresponding to the inner sidewall of the oil container, thereby providing a fire prevention function without a separate fire prevention equipment.  
           [0027]    Meanwhile, the hinge shaft is disposed so that both ends thereof are protruded to an outside of the oil container, and one end of the return spring is coupled to an end of the hinge shaft, and the other end of the return spring is coupled to an outer circumferential surface of the oil container. Therefore, it is not necessary that the return spring should be disposed at an inner portion of the hinge shaft. As the result, a diameter of the hinge shaft is miniaturized and thus the door hinge unit is miniaturized, whereby the door hinge unit can be applied to a refrigerator, a gas oven, a washing machine, a duplicating machine, a scanner, etc. as well as a door of a building or a door of a car. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]    The above objects and other advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which:  
         [0029]    [0029]FIG. 1 is an exploded perspective view of a conventional door hinge unit;  
         [0030]    [0030]FIG. 2 is a perspective view of a door hinge unit according to an embodiment of the present invention;  
         [0031]    [0031]FIG. 3 is an exploded perspective view of the door hinge unit according to the embodiment of the present invention;  
         [0032]    [0032]FIG. 4 is a longitudinal cross-sectional view of the door hinge unit according to the embodiment of the present invention;  
         [0033]    [0033]FIG. 5 is a cross-sectional view taken along a line A-A of the FIG. 4;  
         [0034]    [0034]FIG. 6 is a lateral cross-sectional view of the door hinge unit according to the embodiment of the present invention;  
         [0035]    [0035]FIGS. 7 and 8 are views of the door hinge unit according to other embodiment of the present invention; and  
         [0036]    FIGS.  9  to  11  are views of the door hinge unit according to another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0037]    Now, preferred embodiments of the present invention will be described in detail with reference to the annexed drawings.  
         [0038]    [0038]FIG. 2 is a perspective view of a door hinge unit according to an embodiment of the present invention, FIG. 3 is an exploded perspective view thereof, FIG. 4 is a longitudinal cross-section view thereof, and FIG. 5 is a cross-sectional view taken along a line A-A of the FIG. 4. Referring to each drawing, an oil container of the present invention comprises a cylindrical body  10  of which an upper portion and a lower portion are opened, an upper cover  31  and a lower cover  33  which are respectively screwed to the open upper and lower portions of the cylindrical body  10 , and a washer  32 ,  34  which is disposed at an inner side of the upper and lower cover  31 ,  33 .  
         [0039]    An oil-moving groove  14  is formed in a circumferential direction on an inner sidewall of the cylindrical body  10 . A barrier mounting protrusion  12   a  longitudinally formed on the inner sidewall of the cylindrical body  10  defines a barrier mounting groove  12   b . A barrier  11  having an oil through-path  11   a  is inserted into the barrier mounting groove  12   b . A housing bracket  17  is integrally formed on an outer sidewall of the cylindrical body  10 . The housing bracket  17  may be separately fabricated and then coupled to the cylindrical body  10 .  
         [0040]    At a lower portion of the barrier  11 , there is formed a flow controlling hole  11   c  which connects the oil through-path  11   a  and the cylindrical body  10 . A flow-controlling member  13  for controlling flow of oil passing through the oil through-path  11   a  is screwed in the flow controlling hole  11   c.    
         [0041]    The washer  32 ,  34  that is disposed at the upper and lower cover  31 ,  33  and the inner side of the upper and lower cover  31 ,  33  is formed with a through hole  31   a,    32   a ,  33   a,    34   a  through which a hinge shaft  20  is passed. An oil-leak preventing member such as an o-ring  36 ,  37 ,  38 ,  39  is disposed between the upper and lower cover  31 ,  33  and the cylindrical body  10  and between the upper and lower cover  31 ,  33  and the washer  32 ,  34 .  
         [0042]    The hinge shaft  20  is rotatably disposed in an inner portion of the cylindrical body  10 . A blade  21  that is slidably and closely contacted with the inner sidewall of the housing is formed at the hinge shaft  20 . An upper face and a lower face of the blade  21  are also slidably and closely contacted with an inner sidewall of the washer  32 ,  34 .  
         [0043]    At an upper portion of the hinge shaft  20 , there is formed a fixing portion  22  having a square section. The fixing portion  22  is inserted into a fixing hole  60   a  of a hinge shaft bracket  60  and then fixed by a hinge shaft fixing screw  70 . Therefore, the hinge bracket  60  and the hinge shaft  20  are always integrally rotated without slipping each other. A circumferential surface formed at a center portion of the hinge shaft  20  is slidably and closely contacted with a supporting surface  11   b  formed at an end of the barrier  11 .  
         [0044]    A spring fixing groove  23  is formed at the lower portion of the hinge shaft  20 . An inside end  41  of a return spring  40  is fixedly inserted into the spring fixing groove  23 . An outside end  42  of the return spring  40  is fixedly inserted into a fixing groove of a spring fixing protrusion  42  formed at the lower portion of the cylindrical body  10 . A spring cover  50  is screwed to the lower portion of the cylindrical body  10  so that the return spring  40  is not exposed to an outside.  
         [0045]    A coil spring may be used as the return spring. However, it is preferable that a spiral spring is used as the return spring in order to miniaturize the door hinge unit and increase elastic restoring force.  
         [0046]    The hinge shaft bracket  60  of the door hinge unit according to the present invention, as described above, is fixed to a door of a building or a door of a car, a refrigerator, and a gas oven, etc. Then, the housing bracket  17  is fixed to a doorframe or a main body. In this case, the door hinge unit is used as a housing fixing-hinge shaft rotating type. Meanwhile, in case the both brackets  60  and  17  are reversely fixed to the door and the doorframe or the main body, the door hinge unit is used as a hinge shaft fixing-housing rotating type. Hereinafter, the door hinge unit of the present invention will be described referring to the housing fixing-hinge shaft rotating type.  
         [0047]    When the door, in which the hinge shaft bracket is fixed, is rotated, the blade  21  disposed at the hinge shaft  20  is also rotated together with the door, while being subjected to fluid resistance force of the oil. The viscous oil is moved through the oil through-path  11   a  formed at the barrier  11  and the oil moving groove  14  formed at the inner sidewall of the cylindrical body  10  to a front and rear portion of the blade  21 . Therefore, an opening and closing operation of the door is smoothly and slowly performed.  
         [0048]    Meanwhile, as shown in FIG. 5, the oil moving groove  14  has a different width and depth along a circumferential direction so as to control the flow of the oil passing through the oil moving groove  14  and thus to change the resistance force of the oil exerted on the blade  21 , thereby controlling an opening or closing speed of the door. According to the embodiment, while the door is moved from an opening position to a close position (B) due to the elastic restoring force of the spring, the closing speed of the door is gradually reduced, so that the door is smoothly closed. When the blade  21  is located at a stop portion  14   a  formed to have an internal circumferential surface corresponding to an internal circumferential surface of the cylindrical body at a middle portion of the oil moving groove  14 , since the flowing path of the oil is limited in the oil through-path  11   a  formed at the barrier, the fluid resistance force of the oil exerted on the blade  21  is increased. Therefore, the closing operation of the door is not performed only with the restoring force of the return spring due to a weight of the door and frictional force applied to an outer sidewall of the blade, etc. The door is partially open. Also, in a complete open position (C), the door is kept to be open due to the same principle.  
         [0049]    In this situation, if external force is applied to the door, it is possible that the door is further opened or closed.  
         [0050]    [0050]FIG. 6 shows an embodiment in which a heat detecting member  14   b  formed of a material having a low melting point is provided at the complete open position of the door, i.e., an end of the oil moving groove  14  so as to have an inner sidewall corresponding to the inner sidewall of the oil container, and thus to form the door with a fire prevention function. If the blade  21  is located on the heat detecting member  14   b  at ordinary times, since the oil moving groove  14  is closed, the door is kept to be open. However, when a fire breaks out, the heat detecting member  14   b  is melted by high temperature and the oil moving groove  14  is thus open. Therefore, the door is closed due to the elastic restoring force, thereby preventing the fire from spreading to other regions.  
         [0051]    [0051]FIGS. 7 and 8 are views showing other embodiment of the present invention. A coil spring is used as the return spring  40 . A lower end  41  of the coil spring is fixed to the spring fixing groove  23  of the hinge shaft, and an upper end thereof is fixed inserted into a spring inserting hole  17   a  of the housing bracket  17 . Further, the oil moving groove  14  is formed at the upper surface of the lower washer  34 .  
         [0052]    In this embodiment, although the oil moving groove  14  is formed at the inner wall of an upper or lower portion of the oil container, an operation thereof is performed in the same way in the previous embodiment. Therefore, a description of the operation will be omitted.  
         [0053]    FIGS.  9  to  11  are a perspective view, an exploded perspective view and a longitudinal cross-sectional view of another embodiment of the present invention. In this embodiment, components having the same functions as those in the previous embodiment are designated by the same reference numerals. The description thereof will be also omitted.  
         [0054]    In the door hinge unit of the embodiment, upper and lower hosing covers  231  and  233  are respectively coupled to the open portions of the cylindrical body  10  using a separate screw, so that the housing covers  231  and  233  themselves form the inner wall of the upper and lower portions of the oil container. The barrier  11  having the hinge shaft supporting surface  116  is integrally formed at the cylindrical body  10 . It is also possible that the lower portion of the cylindrical body is formed to be a closed type in the same way as that in the conventional door hinge unit.  
         [0055]    In addition, the hinge shaft bracket  60  is formed with a plate  63 , and rugs  61  and  62  integrally bended at an upper and lower end of the plate  63 . Each of the rugs  61  and  62  has a rectangular hinge shaft fixing hole  60   a  and  62   b  in which the upper and lower portion of the hinge shaft  20  is inserted. The lower rug  62  is formed with a spring fixing hole  62   a . The upper end of the return spring  40  is fixedly inserted into the spring inserting hole  62   a  and the lower end of the return spring  40  is fixedly inserted into the spring inserting groove  17   a  formed at the housing bracket  17 .  
         [0056]    Reference numerals  261  and  263  designate O-rings, and reference numerals  278  and  279  are the oil-leak preventing member comprised of the O-rings  271  and  277 and bushes  273  and  277 .  
         [0057]    According to the door hinge unit of the present invention, as described above, the oil moving groove has a different width and depth along the circumferential direction thereof so as to facilely control the speed of the door according to the open position of the door. Further, a sectional stopping operation of the door can be performed without a separate stopper.  
       Industrial Applicability  
       [0058]    As described above, the power saving outlet according to the present invention is further provided with the up/down moving table and the push button portion so as to safely cut off power even though the plug is not pulled out and further prevent a risk of electrical shock to children due to carelessness when the plug is released from the outlet.  
         [0059]    While the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the spirit and scope of the invention as defined by the appended claims.