WO2008050975A1

WO2008050975A1 - Link device capable of controlling height

Info

Publication number: WO2008050975A1
Application number: PCT/KR2007/005169
Authority: WO
Inventors: Chan Ho Hong; Soon Woo Choi
Original assignee: I-ONE INNOTECH Co Ltd; I One Innotech Co Ltd
Current assignee: I-ONE INNOTECH Co Ltd; I One Innotech Co Ltd
Priority date: 2006-10-23
Filing date: 2007-10-22
Publication date: 2008-05-02
Anticipated expiration: 2009-04-23
Also published as: KR100789666B1

Abstract

Provided is a link device, which can absorb a load and noise which are produced when a door of a refrigerator is inaccurately installed. The link device transfers an automatic return force of a hinge device to a door in which the hinge device is installed at a position spaced from a rotational axis of the door, and includes: a support bracket which is fixed to a main body and into which the rotational shaft of the door is installed; a driving link whose one end is combined with the shaft of the hinge device and which transfers the automatic return force of the hinge device when the door is closed; a follower link whose both ends are pivotably combined between the other end of the driving link and the support bracket to thus enforce the door to return to an initial position according to the automatic return operation; and first and second ball joints which combine both ends of the follower link pivotably with the driving link and the support bracket and movably support a pivot shaft.

Description

[DESCRIPTION]

[Invention Title]

Link Device Capable of Controlling Height

[Technical Field]

The present invention relates to a link device capable of controlling height, and more particularly to a height controllable link device having a ball joint, which can absorb a load and noise which are produced in the case that a door of a refrigerator is inaccurately installed in a door frame.

[Background Art]

A hinge device makes two members spaced from each other around an axis or folded one member over another around the axis, according to necessity. A representative example of the hinge device is a left/right rotational hinge device including a horizontal actuator which is used for a door or window frame, or an up/down rotational hinge device including a vertical actuator which is used for a refrigerator, a mobile phone, or a notebook computer. A conventional hinge device having an automatic return function is disclosed in Korean Laid-open Patent Publication No. 2001 -0027832. Meanwhile, Korean Utility Model Registration No. 0271646 discloses a conventional hinge type door opening and closing apparatus in which a hydraulic type door closer and a spring type door closer are separately configured and the former and the latter are combined with each other. Further, Korean Patent No. 586262 which was proposed by the same inventor as that of the present invention discloses a conventional hinge device employing a double camshaft which includes a lower camshaft and an upper camshaft in which the upper camshaft is installed in order to compensate for reduction in a closing force and includes a pair of spiral elevating holes like the lower camshaft.

In general, a refrigerator door is designed to be automatically closed when the door is opened by an angle of 45 degrees if the door is horizontally fitted. However, the floor of a place that a refrigerator is placed is not horizontally fitted for the most part. Thus, it is usual that the refrigerator is horizontally fitted by adjusting a height control screw which is installed at the front-lower end of the refrigerator at the time of placing the refrigerator, but it is frequent that the refrigerator is horizontally fitted by supporting corners or corner of both sides or one side of the rear end of the refrigerator. By the way, since a space that a refrigerator is placed in an apartment house, etc., is a restricted space which was established beforehand at the time of constructing the apartment house, etc., it is not so easy to level the refrigerator. As a result, most of refrigerators are used at a state where they are properly horizontally fitted.

Therefore, even if the door is opened by an angle of 45 degrees, it may frequently happen that the door is not automatically closed. In particular, in the case that the child or the old uses the refrigerator door carelessly, the refrigerator door may not be completely closed. In this case, loss of cool air occurs to thus increase consumption of electricity. Thus, to solve these problems, hinge devices having an automatic return function for refrigerators are being proposed.

An existing hinge device having an automatic return function for use in a refrigerator is installed in the form of a burial type, in a refrigerator door, in which a rotating axis of the door is used in an equal form as that of the hinge device.

In the meantime, in the case of a two-door type large-size refrigerator, a water discharging hose that is connected to a dispenser which is installed in a freezing chamber is extended to the outside through the rotational axis of the door for the freezing chamber. Accordingly, the hinge device should be placed at and spaced from a position where it is not interfered by the rotational axis of the door. As a result, an automatic return function of a door can be performed by employing a hinge device or a link device having an automatic return function.

In this case, when two doors in a two-door type refrigerator are assembled in the main frame of the refrigerator, heights of the two doors should be accurately set. However, in the case that the two doors are inaccurately set, the heights of the lower sides of the two doors may be differently installed from each other. As being the case, even in the case that lengths of the upper and lower portions of the two doors do not equal minutely due to a manufacturing problem, the same problems as the above may happen. In this case, in order to make heights of two doors equal, it is necessary to control height of any one door. However, a follower link of a two-joint link device for connecting a corresponding door with the main frame of the refrigerator does not keep a horizontal state. As a result, a connection portion of one side or the other side of the follower link is loaded, that is, strained or stressed. For this reason, the automatic return hinge device may not smoothly operate.

For example, the hinge devices disclosed in Korean Patent No. 435188 and Korean Laid-open Patent Publication No. 2005-91094, are buried at a position where they are distant from the rotational axis of a refrigerator door, to thus make the door have an automatic return function by connecting a two -joint link device with a bracket.

By the way, in the conventional art having the above-described two-joint link device, a connection mechanism of connecting a follower link which mutually connects the two-joint link with a driving link and a support bracket is formed of a combination of bolts, pins or nuts. Therefore, in the case that an installation position or the refrigerator door is poor or a dimension of the refrigerator door inequal, the hinge axis of the connection portion for connecting the follower link with the driving link and the support bracket is twisted at the time of opening and closing of the doors. As a result, a friction and a load are created to thus make the hinge device having an automatic return function not smoothly operate due to the created noise and partial wear.

In addition, in the case of a conventional height control mechanism of controlling height of a refrigerator door, since heights of the two doors differ from each other in particular in the case of a two-door type refrigerator, the heights of the two doors are controlled using E-rings for example. For this reason, the automatic return hinge device may not smoothly operate.

Moreover, since a bracket is directly combined with a shaft of a conventional hinge device, through a welding process, it is difficult to modify the conventional hinge device, once the former has been combined with the latter.

[Disclosure] [Technical Problem]

Therefore, to solve the above problems, it is an object of the present invention to provide a link device for a refrigerator door which includes a ball joint whose pivot axis can move at both ends of a follower link, respectively, which absorbs a load and noise which are created since the hinge axis of a connection portion for connecting the follower link with a driving link and a support bracket is twisted at the time of opening and closing of the doors, to thus make a hinge device smoothly operate, without needing to control height of the hinge device or re-installing the hinge device, within an allowable range of heights of a frame hinge and the refrigerator door for a refrigerator, even in the case that the refrigerator door has been inaccurately installed.

It is another object of the present invention to provide a link device for a refrigerator door, which absorbs a load and noise which are created since the hinge axis of a connection portion for connecting the follower link with a driving link and a support bracket is twisted at the time of opening and closing of the doors, even in the case of controlling height of the refrigerator door having a height control mechanism, to thus make the refrigerator door automatically returned.

It is still another object of the present invention to provide a link device which can control a buried position of a hinge device in various positions by changing length between a driving link and a follower link.

[Technical Solution]

To accomplish the above object of the present invention, according to an aspect of the present invention, there is provided a link device which transfers an automatic return force of a hinge device to a door in which the hinge device is installed at a position spaced from a rotational axis of the door in order to provide an automatic return force, the link device comprising: a support bracket which is fixed to the lower end of a main body and into which the rotational shaft of the door is installed; a driving link whose one end is combined with the shaft of the hinge device and which transfers the automatic return force of the hinge device at the time of closing the door; a follower link whose one end is pivotably combined with the other end of the driving link and whose other end is pivotably combined with the support bracket to thus enforce the door to return to an initial position around the rotational shaft according to the automatic return operation of the driving link; and first and second ball joints which combine both ends of the follower link pivotably with the driving link and the support bracket and simultaneously movably support a pivot shaft, wherein each of the first and second ball joints comprises: a bearing supporter having a first throughhole whose inner circumference is formed of an inwardly curved surface and which is fixedly combined with one side of the follower link; a joint ball at the central portion of which a second throughhole is formed and whose outer circumference is movably supported only within the first throughhole of the bearing supporter; and the pivot shaft which is inserted into the second throughhole of the joint ball to thus pivotably connect the follower link with the driving link or the support bracket.

Here, the driving link is made of a linear lever, and the follower link is made of a non-linear lever having a bent portion, or both the driving link and the follower link are made of a linear lever, respectively.

In addition, one side surface of the support bracket is fixedly installed in the lower end of one side of the main body, and the rotational axis of the door is integrally installed in the other side surface which is bent perpendicularly with the one side surface of the support bracket. Here, the hinge device is buried at a position spaced from the rotational axis of the door in the lower end of the door. In addition, diameter of the curved surface of the joint ball is greater than that of the top/bottom entrance of the inner circumference of the first throughhole, and the upper portion and the lower portion of the joint ball are protruded outwardly from the bearing supporter, respectively.

The main body to which the door is supported is a home appliance, in particular, a refrigerator having a dispenser.

According to another aspect of the present invention, there is also provided a link device which transfers an automatic return force of a hinge device to a door for a refrigerator in which the hinge device is installed at a position spaced from a rotational axis of the door in order to provide an automatic return force, the link device comprising: a support bracket which is fixed to the lower end of a main body of the refrigerator and into which the rotational shaft of the door is installed; a driving link whose one end is combined with the shaft of the hinge device and which transfers the automatic return force of the hinge device at the time of closing the door; a follower link whose one end is pivotably combined with the other end of the driving link and whose other end is pivotably combined with the support bracket to thus enforce the door to return to an initial position around the rotational shaft according to the automatic return operation of the driving link; and first and second ball joints which combine both ends of the follower link pivotably with the driving link and the support bracket and simultaneously mo^'vably support a pivot shaft.

Here, the link device is installed only in a freezing chamber door of the refrigerator having a dispenser, or is installed in both the freezing chamber door and a cooling chamber door.

Here, the link device further comprises: a fixing bracket which makes the shaft protrudingly combined outwardly through a throughhole and makes the hinge device buried in the lower end of the door; a fixing nut which is combined with the shaft protrudingly combined outwardly through the throughhole of the fixing bracket so as to be rotationally suppressed, and to which one end of the driving link is fixed; and at least one thrust washer which is combined with the outer circumference of the fixing nut and is inserted between the fixing bracket and the driving link, to thus decrease a frictional resistance at the time of rotation of the shaft and the driving link.

[Advantageous Effects]

As described above, a link device for a refrigerator door according to the present invention is buried at a position spaced from the rotational axis of a door and includes a ball joint respectively at both ends of a follower link, which absorbs a load and noise which are created since the hinge axis of a connection portion for connecting the follower link with a driving link and a support bracket is twisted at the time of opening and closing of the doors, when an automatic return force generated from a hinge device is transferred to the door using a two-joint link, to thus make a hinge device smoothly operate, without needing to control height of the hinge device or re-installing the hinge device, within an allowable range of heights of a frame hinge and the refrigerator door for a refrigerator, even in the case that the refrigerator door has been inaccurately installed, or height of the door is controlled in order to correct the inaccurately installed door.

The link device according to the present invention can control a buried position of a hinge device in various positions by changing length between a driving link and a follower link.

[Description of Drawings]

The above and/or other objects and/or advantages of the present invention will become more apparent by describing the preferred embodiments thereof in detail with reference to the accompanying drawings in which:

FIG. IA is a front view showing a state where a link device according to the present invention and an automatic return hinge device for a refrigerator door using the link device are installed in a two-door refrigerator; FIG. IB is an enlarged cross-sectional view of the link device;

FIG. 1C is a disassembled perspective view of the link device and the hinge device;

FIG. ID is an assembled perspective view of FIG. 1C;

FIG. IE is an enlarged front view showing an installation state of the link device in the case that an installation position of a refrigerator door is poor; and

FIGS. 2A to 2C are top views for explaining an operational state of the refrigerator door including a link device according to the present invention, according to an opening angle of an automatic return hinge device, respectively. [Best Mode]

Hereinbelow, a link device according to the present invention and an automatic return hinge device using the link device for a refrigerator door, according to respective preferred embodiments of the present invention will be described with reference to the accompanying drawings. Like reference numerals denote like elements through the following embodiments.

As illustrated in FIGS. IA to IE, in the case of a link device 10 according to the present invention, a pair of hinge devices 20 which are buried in the lower end portions of doors 2 and 3 for a freezing chamber and a cooling chamber in a two-door type refrigerator 1 are connected with the rotational axes 4 and 5 of the doors 2 and 3, respectively.

The link device 10 according to the present invention is possibly applied to three-door refrigerators. However, the link device 10 can be applied to only a door 2 for a freezing chamber where a dispenser is installed.

In the case that a two-door refrigerator 1 includes a dispenser in the freezing chamber door 2, a hose to discharge extra water that is generated from the dispenser to the outside of the refrigerator is extended to the outside through the rotational axis 4 of the door 2. Therefore, in the case that the doors 2 and 3 exist within a predetermined angle, respectively, the automatic return hinge device 20 having an automatic return function is buried at positions which are spaced from the rotational axes 4 and 5 of the doors 2 and 3 and where there are no interruptions in the lower ends of the doors 2 and 3, respectively, as shown in FIG. IA. Height control screws 6 and 7 to keep parallel at the time of installing the refrigerator are rotatably supported in the lower ends of both sides of a min body Ia of the refrigerator 1.

In the meanwhile, in the case of the two doors 2 and 3, the rotational axis 5 of a support bracket 11 which is fixedly installed in the lower side of the main body Ia of the refrigerator 1 are inserted into and rotatably supported by a coupling hole 3a by the same structure as that of FIG. IA.

Thus, the hinge device 20 and the link device 10 which are installed in a refrigerator door 3 shown in FIGS. IB to IE will be described below.

First, the link device 10 includes a rectilinear lever type driving link 14 whose one end is combined with the shaft of the hinge device 20, and a curved lever type follower link 13 whose one end is pivotably combined with the driving link 14 through a first ball joint 16 and whose other end is combined with a support bracket 11 through a second ball joint 17.

The follower link 13 is preferably designed to minimize a portion which overlaps the driving link 14. As shown, the shape of the follower link 13 is substantially bent once and is formed as an L-shaped curve. The shape of the follower link 13 is determined as an L-shape due to a link ratio between the driving link 14 and the follower link 13. In addition, the shape of the follower link

13 can be made of a rectilinear lever type of an I-shaped form not the L-shaped form, according to a buried position of the hinge device 20. As a result, it is preferable that the shape of the follower link 13 is flexibly varied considering the buried position of the hinge device 20 and the link ratio.

Meanwhile, the hinge device 20 is fixed by the four clamp screws 19 to the lower end surface of the doors 2 and 3 at the state where the hinge device 20 is fixed to a fixing bracket 15 using a pair of a clamp screw 22 and a fixing pin 23. The hinge device 20 is withdrawn downwards through a throughhole of the fixing bracket 15 and is combined with the externally projected shaft 51 by means of the fixing nut 18.

In this case, the leading end portion of the externally projected shaft 51 of the hinge device 20 is cut equally so that both opposite surfaces run parallel to have rectilinear opposite surfaces, and the other portions thereof is formed of a structure having opposite curved surfaces. A throughhole 18a of the shape corresponding to the leading end portion of the shaft 51 is formed in the fixing nut 18 combined with the shaft 51. Therefore, the fixing nut 18 is combined with the shaft 51 with a limited rotation, and the rotational force of the shaft 51 can be transferred to the link device 20 through the fixing nut 18 having a large diameter.

The fixing nut 18 is combined with the shaft 51 of the hinge device 20, the driving link 14 of the link device 10 is combined on the outer circumference of the fixing nut 18, and a clamping bolt 25 is engaged on the upper side of the exposed shaft 51, to thereby prevent the fixing nut 18 from being detached from the shaft 51. The fixing nut 18 and the driving link 14 are fixed to each other by a welding- method, etc.

In this case, a pair of thrust washers 24a and 24b whose inner circumferences are combined with the outer circumference of the fixing nut 18 are inserted between the fixing bracket 15 and the driving link 14. Accordingly, it is preferable that a pair of the thrust washers 24a and 24b should be inserted to reduce a frictional resistance with the fixing bracket 15 at the time of rotation of the shaft 51 and the driving link 14. However, since a pair of the thrust washers 24a and 24b are not essential elements for the hinge device according to the present invention, they may be omitted from the hinge device. Meanwhile, a support bracket 11 which supports the door 3 has a shape of being bent once at right angle. One side surface of the support bracket 11 is fixedly installed in the lower side of the main body Ia of the refrigerator 1, by a number of clamping bolts 12. In addition, a cylindrical rotational axis 5 is projected on the other side of the support bracket 11 to then be inserted into a coupling hole 3a of the door 3.

The first and second ball joints 16 and 17 which are combined in both end portions of the follower link 13 have an equal structure and function. In the first ball joint 16, a bearing supporter 16c having a throughhole 163 whose inner circumference is formed of an introvert curved surface is fixedly coupled on one side of the follower link 13.

A joint ball 16b at the central portion of which a throughhole 162 is formed and whose outer circumference is formed of a curved surface shape corresponding to the introvert curved surface of the throughhole 163 is movably inserted into the throughhole 163 of the bearing supporter 16c. At the normal state, the joints ball 16b is not separated from the throughhole 163 of the bearing supporter 16c. That is, the diameter of the curved surface of the joint ball 16b is made larger than that of the upper/lower entrance of the inner circumference of the first throughhole 163. The upper and lower portions of the joint ball 16b are projected outwards by a predetermined length from the bearing supporter 16c, respectively.

A coupling bolt 16a playing a role of a hinge axis penetrates the second throughhole 162 of the joint ball 16b and the throughhole 14a formed in one side of the driving link 14 to then be engaged with a hexagonal fixing nut 16d. A fixing nut 18 combined with the shaft 51 is fixed to a throughhole 14b formed at the other side of the driving link 14, as will be described later. In this case, a groove 161 for a hexagonal nut which is used at the time of assembling and disassembling the ball joint is formed in the head of the coupling bolt 16a.

Meanwhile, even in the case of the second ball joint 17, a joint ball 17b is movably supported by a bearing supporter 17c fixed to the other side of the follower link 13. A coupling bolt 17a passes through a third throughhole 172 of the joint ball 17b and a throughhole l ib of the support bracket 11a, and then the leading portion of the coupling bolt 17a is engaged with a hexagonal nut 17d.

Therefore, the driving link 14 and the follower link 13 are pivotably connected in the link device 10 according to the present invention by the coupling bolt 16a through the first ball joint 16, that is, the joint ball 16b which is movably supported to one side of the follower link 13. The other side of the follower link 13 is movably and pivotably connected to the support bracket 11 through the second ball joint 17.

As a result, as shown in FIG. IE, even in the case that the follower link 13 and the driving link 14 of the link device 10 do not keep horizontality due to a poor installation position or an inferior dimension of the refrigerator door 3, joint balls

16b and 17b of the first and second ball joints 16 and 17 prevent the coupling bolts

16a and 17a respectively playing a role of the hinge axis from being twisted.

Therefore, a friction and a load which are created by the twisted hinge axis of the connection portion are not generated at the time of opening and closing of the doors 2 and 3. As a result, when using the hinge device 20 having an automatic return function, noise and partial wear are not generated, to thus achieve a smooth operation.

Moreover, even in the case that the refrigerator doors 2 and 3 are inaccurately placed, or even when heights of the doors are controlled to repair the inaccurately installed doors, the automatic return hinge device 20 can be automatically returned smoothly by absorbing the load/noise generated when the hinge device is used.

Meanwhile, the hinge device 30 which is combined with the link device 10 according to the present invention to thus provide an automatic return function is embodied using any types of hinge devices having an automatic return function.

The automatic return hinge device may be applied to for example, any types of hinge devices which may be buried in a door, including hinge devices disclosed in Korean Patent Nos. 538195 and 586262, and Korean Laid-open Patent Publication No. 2007- 14713 all of which were proposed by the same applicant as that of the present invention.

In the case of the automatic return hinge device 20, an upper cap and a lower cap are pressed combined with the upper and lower sides of a body in order to close the inside of the hinge device 20, respectively. In addition, in the case of the automatic return hinge device 20, a shaft 51 which transfers a return force to a door is combined with the fixing nut 18 as described above, while passing through an upper cap. The fixing nut 18 is combined with the driving link 14, in a welding process, etc.

For example, the automatic return hinge device 20, includes: a cylindrical body in the upper end of which an upper cap is combined and whose lower end is blocked by a lower cap which is sealed and combined; a shaft 51 whose upper end is exposed through the upper cap and is extended to the lower side of the body; a piston whose outer circumferential surface is slidably installed along the inner circumferential surface of the body and which partitions the inner portion of the body into upper/lower chambers; a rotational/rectilinear motion conversion unit which converts a rotational motion of the shaft 51 into an axial rectilinear motion of the piston when a rotational force of the door 3 is applied to the shaft according to opening and closing of the refrigerator door; a clamping unit that is installed in the piston and controls a descent and ascent speed of the piston according to the opening and closing of the door 3, and provides a damping function selectively in the case that the piston rises up; and a return unit that provides a restoring force for the rotational/rectilinear motion conversion unit so that the door is returned to an initial position of the door at the time of closing the door. In this case, a compression spring is used as the return unit. Otherwise, the return unit preferably includes: a torsion spring whose one end is fixed to the upper cap and incorporated in the upper portion of the body, and which provides a restoring force for the shaft to make the shaft 51 rotate in the direction of closing the door; and a clutch unit which is associated with the torsion spring, to thus interrupt an increase in an elastic force of the torsion spring in the case that a current opening angle exceeds a predetermined opening angle at the time of opening and closing the door and restore the elastic force of the torsion spring in the case that a current opening angle does not exceed the predetermined opening angle at the time of opening and closing the door. Here, in the case that a current opening angle exceeds the predetermined opening angle, it is possible to maintain the door at an angle set by a user in a temporary stop state.

If the shaft 51 rotates at the door opening time in the case that the hinge device includes the clutch unit, the torsion spring is twisted and deformed in association with the rotation of the shaft 51. Thereafter, the clutch unit reaches for example a predetermined clutching opening angle of 45 degrees, the clutch unit is activated and the twist deformation of the torsion spring stops.

Accordingly, only the shaft 51 is rotated and opening of door is easily achieved.

At the time of automatically returning the door, the clutching operation of the clutch unit is released from the opening angle of less than 45 degrees, and thus the shaft 51 is made to rotate clockwise by the restoring force from the torsion spring which has been at the reversely twisted state. As a result, the door is made to perfectly return to the initial position, that is, to be locked.

However, for example, in the case of the automatic return hinge device which employs both the return spring and the torsion spring, it is possible to establish the clutching opening angle of the clutch unit at a desired angle, for example, at an angle of 30 degrees.

Hereinbelow, the operation of the hinge device 20 which is respectively buried in the lower ends of the doors 2 and 3 and combined with the link device 10 to thus provide an automatic return function for the doors 2 and 3 will be described in detail with reference to FIGS. 2A to 2C.

A. At the door opening time

In a hinge device for a refrigerator having a link device according to the present invention, when a door 3 is made opened as shown in FIG. 2B, from the state where the door has been closed, that is, from the initial state where the door has been stopped, as shown in FIG. 2A, that is, when a cooling chamber door 3 for a refrigerator is opened clockwise, a driving link 14 of a link device 10 rotates counterclockwise according to opening of the door 3, and a follower link 13 rotates clockwise. When the driving link 14 rotates counterclockwise, the external rotational force is delivered so that the shaft 51 of the hinge device 20 connected via the fixing nut 18 also rotates counterclockwise. Accordingly, the return spring or the torsion spring which is incorporated in the hinge device 20 as the return unit is compressed or inversely twisted to thus generate an elastic force. Thereafter, if the user continuously rotates the door, the rotational movement of the door 3 is limited to the door opening angle of 135 degrees, by a stopper provided in the refrigerator, as shown in FIG. 2C. Meanwhile, in the case that such a stopper is not provided in a refrigerator, the door opening angle is determined according to the structural characteristics of the driving link 14 and the follower link 13 of the link device.

B. At the door closing time

In the meantime, when the cooling chamber door 3 is made closed as shown in FIG. 2C- 2A, and the door reaches a predetermined door opening angle, the hinge device 20 having the automatic return function is activated to provide a return force so that the door 3 can be automatically returned to the initial position via the link device 20.

First, if the door 3 rotates counterclockwise up to a predetermined door opening angle according to application of the rotational force by a user, the driving link 14 of the link device 10 rotates clockwise, and the follower link 13 rotates counterclockwise.

In this case, when a cam diagram of elevating guide holes included in a rotational/rectilinear motion conversion unit of the hinge device 20 includes a temporary stop section of the door and the hinge device 20 employs a compression spring, and if the door opening angle is beyond the temporary stop section of the door, the restoring force of the compression spring is applied to the shaft 51 as the rotational force of the clockwise direction. Accordingly, the closing force is applied to the door through the link device 10, and thus the door 3 is automatically returned to the initial position. In addition, the case that the hinge device 20 employs a torsion spring and a clutch unit, instead of the compression spring, and if the shaft 51 rotates clockwise and the door opening angle becomes 45 degrees or less which is the clutching start angle when the door 3 is closed with a predetermined force, the clutch unit is released and the elastic restoring force of the torsion spring is applied to the shaft 51 as the rotational force of the clockwise direction. Accordingly, the closing force is applied to the door through the link device 10, and thus the door 3 is automatically returned to the initial position.

That is, if the door 3 rotates counterclockwise and the compression spring or the torsion spring reaches the door opening angle which provides the restoring force, the elastic restoring force is applied to the shaft 51. Accordingly, the fixing nut 18 combined with the shaft 51 and the driving link 14 of the link device 10 which is fixed to the outer circumference of the fixing nut 18 by welds rotate clockwise together while the shaft 51 rotates clockwise.

Moreover, if the leading end of the driving link 14 rotates clockwise around the shaft 51 which functions as a pivot axis, one end of the follower link 13 whose other end is pivotably supported to a support bracket 11 through a second ball joint 17 is pulled clockwise. Finally, the door 3 rotates counterclockwise around the rotational axis 5 of the door 3 together with the follower link 13 to then be closed. In this case, even in the case that the follower link 13 and the driving link 14 of the link device 10 do not maintain a horizontal state due to the poor installation position and dimension of the cooler chamber door 3 in the present invention, joint balls 16b and 17b of the first and second ball joints 16 and 17 can prevent coupling bolts 16a and 17a playing a role of a hinge shaft, respectively from be twisted, to thereby block the friction and load which may be caused when the hinge shaft of the connection portion is twisted at the time of opening and closing the door 2 or 3. As a result, when the hinge device 20 having the automatic return function does not generate noise and partial wear and smoothly operates. Moreover, a link device for a refrigerator door according to the present invention and a hinge device using the link device according to the present invention, can absorb a load and noise which are created since the hinge axis of a connection portion for connecting the follower link with a driving link and a support bracket is twisted at the time of opening and closing of the door, even in the case that the refrigerator door 2 or 3 has been inaccurately installed, or height of the door is controlled in order to correct the inaccurately installed door.

The case that the link device and the hinge device have been applied in the automatic return refrigerator door has been described in the embodiments of the present invention. However, the link device according to the present invention and the hinge device having the link device can be applied to various home appliances and building doors which require an automatic return function, without a big modification.

As described above, the present invention has been described with respect to particularly preferred embodiments. However, the present invention is not limited to the above embodiments, and it is possible for one who has an ordinary skill in the art to make various modifications and variations, without departing off the spirit of the present invention. Thus, the protective scope of the present invention is not defined within the detailed description thereof but is defined by the claims to be described later and the technical spirit of the present invention.

[Industrial Applicability]

As described above, a link device according to the present invention can be applied to a case that an automatic return force of an automatic return hinge device is transferred to a main body in various kinds of home appliances or building doors in which a buried type automatic return hinge device is not installed in the rotational axis of the doors like a case that a freezing chamber door for a two-door type refrigerator includes a dispenser.

Claims

[CLAIMS]

[Claim 1 ]

A link device which transfers an automatic return force of a hinge device to a door in which the hinge device is installed at a position spaced from a rotational axis of the door in order to provide an automatic return force, the link device comprising: a support bracket which is fixed to the lower end of a main body and into which the rotational shaft of the door is installed; a driving link whose one end is combined with the shaft of the hinge device and which transfers the automatic return force of the hinge device at the time of closing the door; a follower link whose one end is pivotably combined with the other end of the driving link and whose other end is pivotably combined with the support bracket to thus enforce the door to return to an initial position around the rotational shaft according to the automatic return operation of the driving link; and first and second ball joints which combine both ends of the follower link pivotably with the driving link and the support bracket and simultaneously movably support a pivot shaft, wherein each of the first and second ball joints comprises: a bearing supporter having a first throughhole whose inner circumference is formed of an inwardly curved surface and which is fixedly combined with one side of the follower link; a joint ball at the central portion of which a second throughhole is formed and whose outer circumference is movably supported only within the first throughhole of the bearing supporter; and the pivot shaft which is inserted into the second throughhole of the joint ball to thus pivotably connect the follower link with the driving link or the support bracket.

[Claim 2]

The link device according to claim 1, wherein the driving link is made of a linear lever, and the follower link is made of a non-linear lever having a bent portion.

[Claim 3]

The link device according to claim 1, wherein both the driving link and the follower link are made of a linear lever, respectively.

[Claim 4]

The link device according to claim 1, wherein one side surface of the support bracket is fixedly installed in the lower end of one side of the main body, and the rotational axis of the door is integrally installed in the other side surface which is bent perpendicularly with the one side surface of the support bracket, and wherein the hinge device is buried at a position spaced from the rotational axis of the door in the lower end of the door.

[Claim 5]

The link device according to claim 1, wherein diameter of the curved surface of the joint ball is greater than that of the top/bottom entrance of the inner circumference of the first throughhole, and the upper portion and the lower portion of the joint ball are protruded outwardly from the bearing supporter, respectively.

[Claim 6]

The link device according to claim 1, wherein the main body to which the door is supported is a home appliance.

[Claim 7] A link device according to claim 6, wherein the home appliance is a refrigerator.

[Claim 83

The link device according to claim 1, further comprising: a fixing bracket which makes the shaft protrudingly combined outwardly through a throughhole and makes the hinge device buried in the lower end of the door; a fixing nut which is combined with the shaft protrudingly combined outwardly through the throughhole of the fixing bracket so as to be rotationally suppressed, and to which one end of the driving link is fixed; and at least one thrust washer which is combined with the outer circumference of the fixing nut and is inserted between the fixing bracket and the driving link, to thus decrease a frictionai resistance at the time of rotation of the shaft and the driving link.