Patent Publication Number: US-9885206-B2

Title: Sliding door self-closing device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims benefit of and priority to Korean Patent Application No. 2016-0053994, filed in the Korean Patent Office on May 2, 2016, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The present disclosure relates to a sliding door self-closing device, and more particularly, to a sliding door self-closing device capable of allowing a sliding door to be appropriately driven even on a deformed rail and facilitating removal of the sliding door from the deformed rail. 
     BACKGROUND 
     In general, doors are classified into a hinged type and a sliding type depending on its open/close mechanism. In the case of the hinged type, a hinge structure is installed between a wall and a door to allow the door to be opened or closed as the door is pushed or pulled. In the case of the sliding type, a rail is installed above or below the door, and the door is opened or closed by sliding along the rail. 
     In the sliding type, an integrated module of a roller assembly and a damper also slides along the rail provided above the door. In this case, if a significantly long rail is deformed, or the rail is irregularly deformed by an external force, it is difficult to appropriately drive the roller assembly and the damper designed to internally slide along the rail due to the deformed rail. 
     An extension rail is provided in straight alignment with the rail in order to allow a user to perform maintenance or inspection by removing the roller assembly and the damper from the rail. However, if the rail is deformed as described above, it is difficult to separate the extension rail and then remove the roller assembly and the damper from the rail through the removed space. 
     PATENT LITERATURES 
     [Patent Literature 1] Korean Utility Model Application No. 20-2013-0001671 (Registration No. 20-0474484) 
     SUMMARY 
     In view of the aforementioned problems, the present disclosure provides a sliding door self-closing device by which the damper and the roller assembly can be appropriately driven along the rail even when the rail is deformed, and the damper and the roller assembly can be easily removed through a short space of the extension rail. 
     According to an aspect of the present invention, there is provided a self-closing device configured to automatically close a door moving along a rail aligned straightly with an extension rail. The sliding door self-closing device includes: a damper configured to move along the rail to automatically close the door and smoothen a closing speed; and a roller assembly pivotably connected to a front end of the damper to move along the rail. The damper has a body configured to automatically close the door and smoothen a closing speed, an insertion block disposed at the front end of the body and provided with a connection ball protruding on its front end, a metal casing provided in outer side surfaces of the body and the insertion block to fix the body and the insertion block, and a roller provided at the rear end of the metal casing. The roller assembly has a body, two pairs of rollers provided in front and rear sides of the body, a connection block provided with a receptacle cavity integratedly formed in the rear end of the body to receive the connection ball and an insertion hole into which a front part of the insertion block is inserted so that the rear end adjoins with the stoppers to prevent the roller assembly from pivoting upward about the damper, and a fixing pin provided to extend horizontally across the connection block to prevent the connection ball inserted into the receptacle cavity from being removed from the upper side of the receptacle cavity. 
     Here, a lower part of the receptacle cavity of the connection block has a curved tapered shape whose diameter is gradually reduced downward, so that the connection ball is prevented from being removed from a lower side of the receptacle cavity. 
     Preferably, a lid is provided in an upper side of the inside of the receptacle cavity. 
     Preferably, an insertion tube is provided in an upper side of the front end of the insertion block, and a coil spring is provided inside the inner tube, so that a tip of the coil spring abuts on an outer side surface of the lid when the damper and the roller assembly are aligned straightly. 
     Preferably, a predetermined gap is formed between an outer side surface of the insertion block of the damper and an inner wall surface of the connection block provided with the insertion hole, and the roller assembly is rotated with respect to the connection ball by a predetermined angle within a range of the gap. 
     Preferably, the sliding door self-closing device further includes a roller bracket fixed to an upper end of the door. The roller bracket is fastened to a locking nut provided inside the body of the roller assembly in a thread coupling manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 to 3  are perspective views illustrating a sliding door self-closing device according to an embodiment of the invention; 
         FIG. 4  is a diagram illustrating a sliding door self-closing device, a rail, and an extension rail according to an embodiment of the invention; 
         FIGS. 5A and 5B  are diagrams illustrating pivoting and rotating operations of a roller assembly of the sliding door self-closing device according to an embodiment of the invention; 
         FIG. 6  is a partially cross-sectional view illustrating the sliding door self-closing device according to an embodiment of the invention; 
         FIGS. 7A and 7B  are diagrams illustrating a state of the sliding door self-closing device installed in the rail according to an embodiment of the invention; and 
         FIG. 8  is a perspective view illustrating a state of the sliding door self-closing device removed from the rail according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     A sliding door self-closing device according to preferred embodiments of the present invention will now be described with reference to the accompanying drawings. 
       FIGS. 1 to 3  are perspective views illustrating a sliding door self-closing device according to an embodiment of the invention.  FIG. 4  is a diagram illustrating a sliding door self-closing device, a rail, and an extension rail according to an embodiment of the invention.  FIGS. 5A and 5B  are diagrams illustrating pivoting and rotating operations of a roller assembly of the sliding door self-closing device according to an embodiment of the invention. 
       FIG. 6  is a partially cross-sectional view illustrating the sliding door self-closing device according to an embodiment of the invention.  FIGS. 7A and 7B  are diagrams illustrating a state of the sliding door self-closing device installed in the rail according to an embodiment of the invention.  FIG. 8  is a perspective view illustrating a state of the sliding door self-closing device removed from the rail according to an embodiment of the invention. 
     The sliding door self-closing device according to the present invention is a device for automatically closing a door D sliding along a rail R straightly aligned with an extension rail E. 
     The sliding door self-closing device includes a damper  100 , a roller assembly  200  rotatably connected to a front end of the damper  100 , and a roller bracket  300  connected to the roller assembly  200 . 
     When the door D is closed, the damper  100  moves along the rail R and is operated to automatically and perfectly close the door D at the door closing end of the rail D. In addition, the damper  100  is operated to smoothen a closing speed of the door D. 
     The damper  100  has a body  110 , an insertion block  120  placed at the front end of the body  110 , a metal casing  130  provided in an outer side surface of the insertion block  120 , and a roller  140  provided at the rear end of the metal casing  130 . 
     The body  110  is internally provided with a cylinder or spring (not shown), a switch, or the like to smoothen the closing speed while perfectly closing the door D. These components such as the cylinder or spring are well known in the art, and will not be described in detail herein for simplicity purposes. 
     The insertion block  120  is fabricated in a hexahedral shape and is disposed at the front end of the body  110 . In addition, the insertion block  120  has a protruding connection ball  121 , a pair of stoppers  12  protruding on both side surfaces, and a protruding insertion tube  123  disposed above the connection ball  121 . 
     The connection ball  121  protrudes in the center of the front end of the insertion block  120  in an integrated manner and has a ball-shaped tip. The connection ball  121  having such a ball shape is inserted into a receptacle cavity  231  of the roller assembly  200  as described below. 
     The stoppers  122  protrude from the upper parts on both side surfaces of the insertion block  120 . The stoppers  12  adjoin with the rear end of a connection block  230  of the roller assembly  200  as described below, so that the roller assembly  200  is prevented from pivoting upward with respect to the damper  100 . When the roller assembly  200  and the damper  100  are aligned straightly, the stoppers  122  protrudes from gaps between the connection block  230  of the roller assembly  200  and the metal casing  130  as described below while their front ends adjoin with the connection block  230 , and their rear ends adjoin with the metal casing  130 . 
     The insertion tube  123  protrudes from the upper part on the front end of the insertion block  120 . The insertion tube  123  is internally provided with a coil spring  123   a . The roller assembly  200  is pivotable vertically about the front end of the damper  100 . When the roller assembly  200  and the damper  100  are aligned straightly during the pivoting, the rear end of the coil spring  123   a  abuts on a lid  250  described below. 
     The metal casing  130  is provided along the outer side surfaces of the body  110  and the insertion block  120  to fix the body  110  and the insertion block  120 . The metal casing  130  is formed of metal such as aluminum to reinforce the body  110 . If the self-closing device is used for a long time, the body  110  formed of a plastic material may be stressed for a long time. In some cases, the body  110  may be fractured on its side surface due to such a stress. In order to reinforce the body  110 , the body  110  is fixed to the metal casing  130  on its both side surfaces. 
     The rollers  140  are provided in both sides of the rear end of the metal casing  130  to allow the body  110  to slide along the rail R. 
     The roller assembly  200  guides the door D when the door D is opened or closed. The roller assembly  200  is pivotally connected to the front end of the damper  100  and moves along the rail R. 
     The roller assembly  200  includes a body  210 , two pairs of rollers  220  provided in front and rear sides of the body  210 , a connection block  230  integrated into the rear end of the body  210 , a fixing pin  240  provided horizontally across the connection block  230 , and a lid  250  provided inside the body  210 . 
     The body  210  has an internal locking nut  211  provided in its inner center and fastened to the roller bracket  300 . 
     The locking nut  211  prevents the roller assembly  200  from being unfastened from the roller bracket  300 . If an automatic fastener is installed and used for a long time for this purpose, a continuous vibration applied thereto may weaken a coupling force between the roller assembly  200  and the roller bracket  300 , and they may be finally released. In order to prevent such a failure, the locking nut  211  and the roller bracket  300  are fastened to each other in a thread coupling manner. 
     At least four rollers  220  are installed in both sides of the front and rear ends of the body  210 . 
     The connection block  230  has a vertically penetrating receptacle cavity  231  and an insertion hole  231  provided in rear of the receptacle cavity  231  to communicate with the receptacle cavity  231 . 
     In the connection block  230  formed in this manner, its rear end comes in contact with front ends of the stoppers  122  of the insertion block  120  when the damper  100  and the roller assembly  200  are aligned straightly. As a result, it is possible to the roller assembly  200  from being pivoted upward with respect to the damper  100 . Therefore, while the roller assembly  200  is pivotable downward about the damper  100  up to an angle of, approximately, 90°, its upward pivoting is prevented. In addition, the roller assembly  200  is prevented from horizontally pivoting about the damper  100 . 
     The receptacle cavity  231  is formed to vertically penetrate in the center of the connection block  230 . The connection ball  121  of the insertion block  120  is inserted into the inside of the receptacle cavity  231  so that it is revolved inside the receptacle cavity  231  when the roller assembly  200  is pivoted about the damper  100 . 
     Meanwhile, the receptacle cavity  231  has a curved tapered shape whose diameter is gradually reduced downward, so that a diameter of the lower end of the receptacle cavity  231  is smaller than an outer diameter of the connection ball  121 . Therefore, the connection ball  121  is prevented from being removed through the lower side of the receptacle cavity  231 . In addition, since the lower wall surface of the connection block  230  of the receptacle cavity  231  is cured as described above, it does not hinder the revolution of the connection ball  121 . 
     The insertion hole  232  is formed in the rear end of the connection block  230  and communicates with the receptacle cavity  231 . The front part of the insertion block  120  is inserted into the inside of the insertion hole  232 . When the insertion block  120  is inserted into the insertion hole  232 , the outer side surface of the insertion block  120  and the inner wall surface of the connection block  230  provided with the insertion hole  232  do not abut on each other, but are separated by a predetermined gap. Therefore, the roller assembly  200  is rotated by a certain angle θ with respect to the connection ball  121  within a range of the gap. That is, when the roller assembly  200  is rotated with respect to the connection ball  121  provided in the center of the front end of the damper  100 , the inner wall surface of the connection block  230  provided with the insertion hole  232  comes in contact with the outer side surface of the front part of the insertion block  120 , and the roller assembly  200  is not rotated any more. Therefore, the rotation of the roller assembly  200  is restricted. Preferably, a rotation angle of the roller assembly  200  with respect to the connection ball  121  is set to, approximately, ±5° with respect to the connection ball  121 . In general, even the rail R employed in typical furniture is distorted, its distortion angle is not significant. It is considered that the roller assembly  200  can be appropriately operated inside the rail R if the distortion angle is within ±5°. 
     The fixing pin  40  is provided to prevent the connection ball  121  of the insertion block  120  inserted into the receptacle cavity  231  from being removed from the upper side of the receptacle cavity  231 . As described above, since the diameter of the lower end of the receptacle cavity  231  is smaller than the diameter of the connection ball  121 , the connection ball  121  is prevented from being removed to the lower side of the receptacle cavity  231 . In addition, since the fixing pin  240  provided across the receptacle cavity  231  restricts the connection ball  121 , the connection ball  121  is also prevented from being removed to the upper side of the receptacle cavity  23 . 
     The lid  250  is installed in the upper side of the receptacle cavity  121  to prevent a foreign object from intruding into the inside of the receptacle cavity  231 . 
     As described above, the coil spring  123   a  is provided in the insertion tube  123  of the insertion block  120 . When the damper  100  and the roller assembly  200  are aligned straightly, a tip of the coil spring  123   a  abuts on the outer surface of the lid  250 . 
     The roller bracket  300  is connected to the body  10  of the roller assembly  200  and is fixed to the upper end of the door D. The roller bracket  300  is fastened to the locking nut  211  provided in the inside of the body  210  of the roller assembly  200  in a thread coupling manner. 
     In other words, the roller bracket  300  is extruded from the rail R and is connected to the body  210  as well as the door D. Therefore, the rollers  220  of the roller assembly  200  is placed inside the rail R to support the door D and allow movement of the door D. 
     The sliding door self-closing device according to the present invention will now be described in more details. The extension rail E is placed in a door opening start position in the door opening direction such that the rail R is straightly aligned with the extension rail E. The self-closing device obtained by assembling the damper  100 , the roller assembly  200 , and the roller bracket  300  is installed in an upper end of the door D, and the rail R is then installed. 
     If the rail R is deformed by an external force in this state, it is difficult to appropriately drive the damper  100  and the roller assembly  200  sliding along the rail R only by a rectilinear motion. 
     In this case, if the roller assembly  200  is vertically pivoted by a certain angle about the damper  100 , or the roller assembly  200  is rotated with respect to the connection ball  121  by a certain angle as much as the deformation of the rail R, the door D can be appropriately driven even along the deformed rail D. 
     Meanwhile, in order to check the damper  100  or the roller assembly  200  installed in the rail R for maintenance or inspection purposes, it is necessary to remove the extension rail E and then remove the damper  100  or the roller assembly  200  from the rail R. 
     However, it is difficult to remove the damper  100  and the roller assembly  200  from the rail R because the extension rail E typically has a length of 10 cm, and a total length of the damper  100  and the roller assembly  200  is typically much longer than that of the extension rail E. For this reason, according to an embodiment of the present invention, the damper  100  and the roller assembly  200  are rotatably connected. Since the damper  100  and the roller assembly  200  are not fixed to each other, the coil spring  123   a  is provided to evenly transmit a force to the damper  100  and the roller assembly  200 . In this configuration according to an embodiment of the present invention, it is possible to easily remove the damper  100  and the roller assembly  200  from the rail R by rotating the damper  100  and the roller assembly  200  in a space formed by removing the extension rail E. 
     In the sliding door self-closing device according to the present invention, the roller assembly is vertically pivoted about the damper, and the roller assembly is rotated with respect to the connection ball of the damper within a predetermined small angle range. Therefore, it is possible to ensure appropriate driving along the rail even when the rail is deformed. In addition, it is possible to easily remove the damper and the roller assembly through a short space of the extension rail. 
     An elastic force of the coil spring is evenly transmitted to the damper and the roller assembly when the damper and the roller assembly are straightly aligned. Therefore, the rollers of the damper and the rollers of the roller assembly abut on the rail. Accordingly, it is possible to facilitate sliding of the door.