WO2006025663A1

WO2006025663A1 - Slim type hinge apparatus having automatic return function

Info

Publication number: WO2006025663A1
Application number: PCT/KR2005/002739
Authority: WO
Inventors: Soon Woo Choi
Original assignee: I-One Innotech Co., Ltd.
Priority date: 2004-08-20
Filing date: 2005-08-19
Publication date: 2006-03-09
Also published as: CN101006243B; KR20060017228A; CN101006243A; KR100644009B1

Abstract

A slim hinge apparatus having an automatic return function is provided, which compensates for a reduction of a door damping force which occurs due to removal of an outer case and a reduction of a chamber diameter. The hinge apparatus includes a number of guide vessels having a number of independent chambers in a cylindrical first guide vessel where first and second vertical guide holes in which the number of guide vessels are sequentially coupled, and an ascending and descending apparatus which makes a guide pin up and down by a rotational moment when a door is rotated. A number of hydraulic circuits formed in the number of chambers include a piston rod which ascends and descends according to ascending and descending of a guide pin, and a number of pistons which partition a number of chambers up and down, respectively.

Description

[DESCRIPTION]

[invention Title]

SLIM TYPE HINGE APPARATUS HAVING AUTOMATIC RETURN FUNCTION [Technical Field]

The present invention relates to a slimhinge apparatus having an automatic return function, and more particularly, to a slimhinge apparatus having an automatic return function which includes at least two independent hydraulic circuits in order to compensate for a reduction in a door damping force which occurs due to removal of an outer case of the hinge apparatus and simultaneously a reduction in diameter of a chamber, to thereby minimize diameter of the hinge apparatus and to further comprise an oil chamber and a check valve to thereby increase a door damping force in case of having an identical outer diameter. [Background Art]

A hinge apparatus makes two members spaced from each other or folded one member over another around a shaft, according to necessity. A representative example of the hinge apparatus is a left/right rotational hinge apparatus including a horizontal actuator which is used for a door or window frame, or an up/down rotational hinge apparatus includingavertical actuatorwhichisusedfora refrigerator, a mobile phone, or a notebook computer.

A conventional hinge apparatus having an automatic return function is disclosed in Korean Laid-open Patent Publication No. 2001-0027832.

In the case of the conventional hinge apparatus, a conversion head which ascends and descends according to rotation of a door are guided by a pair of guide pins. The guide pins are fixed to hinge knuckles. Also, a cylinder and the conversion head are incorporated in the knuckles of four or so. Accordingly, since the movable hinge knuckles receive big load and rotate for a long time, durability of the hinge apparatus is lowered and since the structure is complicated, an assembly productivity deteriorates.

Also, since a compression spring for performing an automatic return of a door is arranged in the upper side of the conversion head, and a hydraulic circuit for adjusting a return speed of the door is arranged in the lower side of the conversionhead, it is difficult to reduce the total length of the hinge apparatus. Further, since the length of a space where the compression spring is disposed is limited only in the upper side of the conversion head, a large restoring force cannot be provided for automatic return of the door. Accordingly, it is difficult to apply the conventional hinge apparatus to a large-scale door.

Also, the inner portion of the hinge apparatus and a mechanism of connecting the fixed portion and the movable portion of the hinge apparatus are applied only in the hinge apparatus. As a result, it is not possible to apply the hinge apparatus to a structure that the center of a door differs from that of the hinge apparatus. Also, a fixing unit for temporarily fixing the door so that the door does not rotate at the state where the door is opened at a predetermined angle is not installed in the hinge apparatus. Accordingly, it is inconvenient for users to use the hinge apparatus.

Meanwhile, Korean Utility Model Registration No.

0271646 discloses a hinge door opening and closing apparatus in which a hydraulic door closer and a spring door closer are separately configured and the former and the latter are combined with each other.

Meanwhile, the conventional art has not provided an optimized structure of a left/right or up/down rotational door hinge apparatus which is applied in a Kimchi refrigerator for use in a storage device for storing a fermentation food such as Kimchi which is one of Korean traditional foods, a general refrigerator, a vehicle trunk, and so on.

Also, Korean Patent Registration No. 435188 discloses a hinge apparatus using a single cam shaft having a spiral cam diagram whose multi-stage automatic return speed establishment structure is stabilized. However, it is difficult to bury the conventional hinge apparatus into a door since an outer case is needed outwards and thus the total diameter is formed larger than the thickness of the door.

If a cam shaft and a chamber are reduced in diameter so that the conventional hinge apparatus can be buried into and used for a door, a sufficient damping force required for closing a door can be obtained from the hinge apparatus. As a result, a door closing speed is not controlled at the time of an abrupt door return.

In particular, in the case of a large-scale door, the force of inertia thereof is not appropriately controlled if a damping force is small when a large external force is applied to the large-scale door. [Disclosure] [Technical Problem]

To solve the above problems, it is an object of the present invention to provide a slim hinge apparatus having an automatic return function which includes at least two independent hydraulic circuits in order to compensate for a reduction ina doordamping forcewhichoccurs due to removal of an outer case of the hinge apparatus and simultaneously a reduction in diameter of a chamber, to thereby minimize diameter of the hinge apparatus .

It is another object of the present invention to provide a slim hinge apparatus adding an oil chamber and a check valve to thereby increase a door damping force in the case that an identical outer diameter is given.

It is still another object of the present invention toprovide a slimhinge apparatus which ismade slimbyremoval of an outer case and increases a damping force by addition of a hydraulic circuit, to thus be applicable to the inner portion of a small-scale door as well as a large-scale door as a burial type. [Technical Solution] Toaccomplishtheaboveobject ofthepresentinvention, according to an aspect of the present invention, there is provided a slimautomatic returnhinge apparatus comprising: a cylindrical first guide vessel in which first and second vertical guide holes are formed up and down in positions facing each other; a cylindrical second guide vessel in which the upper side of a first isolator is detachably coupled with the lower end of the cylindrical first guide vessel and a first chamber isolated fromthe cylindrical first guide vessel is provided in the lower side of the first isolator; a cylindrical third guide vessel in which the upper side of a second isolator is detachably coupled with the lower end of the cylindrical second guide vessel and a second chamber isolated from the first chamber of the cylindrical second guide vessel is provided in the lower side of the second isolator; a camshaft which is rotatably installed in theinnercircumferenceofthecylindrical firstguidevessel, in which first and second ascending and descending guide holes having a respectively symmetrical spiral shape are penetratingly formed along the outer circumference of the cylindrical body of the camshaft so that the first and second ascendinganddescendingguideholes canbemovedwithrespect to each other, and a shaft protrudes so that the upper end of the cylindrical body thereof penetrates the upper end of the first guide vessel; a guide pin whose both ends are coupled with first and second vertical guide holes via the first and second ascending and descending guide holes, respectively, andwhich is movably disposedup and down along the first and second ascending and descending guide holes according to relative rotation of the camshaft or the first to third guide vessels depending upon opening and closing of a door; first and second piston rods whose upper ends are sequentially coupled with the guide pin and lower ends are extended to a second chamber via the first chamber, so as to slide up and down along the inner circumference of the first and second isolators of the first and second guide vessels; first and second pistons which are coupled with the first and secondpiston rods, respectively, in which the first and second chambers are partitioned into the upper and lower portions, respectively, and which includes first and second oil paths through which oil in the first and second chambers flows in the upper and lower chambers; first and second check valves which open and close selectively the first and second oil paths according to ascending and descending of the first and secondpistons, to thereby increase and decrease an amount of oil which flows via the oil paths and thus control an ascendinganddescendingspeedofthe first andsecondpistons; a sealing cap which is detachably coupled with the lower end of the third guide vessel at a sealed state; and an elastic member which is installed between the second piston and the sealing cap, and which provides a restoring force which is compressed according to opening of the door and raises the second piston according to closing of the door.

The automatic return hinge apparatus further comprises at least one hydraulic circuit in order to increase a damping force of the hinge apparatus.

In this case, the hydraulic circuit includes a guide vessel which is inserted between the second and third guide vessels, having an independent chamber therein, a piston which is slidably inserted into the chamber, and a piston rod which connects between the first and second pistons.

In the hinge apparatus according to the present invention, the first oil path communicates with the upper portion of the first chamber via a first recess formed at the lower-center of the first piston rod, and communicates with the lower portion of the first chamber via a second recess formed at the upper-center of the second piston rod.

Also, the second oil path communicates with the upper portion of the second chamber via a third recess formed at the lower-center of the second piston rod, in which the lower portion of the second oil path communicates with the lower portion of the second chamber.

Also, the first and second check valves employ circular or spherical valve actuators which are inserted into the first and second oil paths, respectively, to thus control an amount ofoil flowingselectivelybetweentheupperandlowerportions of the first and second chambers.

The first and second ascending and descending guide holes include at least a first ascending and descending section of a door opening angle of 0°to 15°, a second ascending and descending section of a door opening angle of 15°to 90°, and a stoppage section of a door opening angle of 90°to 130°, respectively.

Also, in the hinge apparatus according to the present invention, the guide pin is moved up and down along the first and second ascending and descending guide holes according to relative rotation of the first through third guide vessels at the shaft of the camshaft depending upon opening and closing the door, in which the guide pin is buried into the inner portion of the door. According to another aspect of the present invention, there is provided a slim automatic return hinge apparatus comprising: a shaft; a cylindrical first guide vessel which rotatably supports the shaft with respect to the inner circumference thereof; a number of guide vessels which are sequentially detachably coupled with the lower side of the first guide vessel, and which includes an isolator in the upper sides thereof and a number of independent chambers provided below the isolator; an ascending and descending unit which is installed in the inner circumference of the first guide vessel and makes the guide pins move up and down by a rotational moment occurring in the shaft or the first guide vessel when a door rotates; a number of hydraulic circuits including piston rods which are inserted into the number of guide vessels, whose upper portions are connected with the guide pin in the ascending and descending unit, and which ascend and descend according to ascending and descending of the guide pins, and a number of pistons which are coupled mutually with the piston rods at certain intervals and partition the number of chambers up and down, respectively, in which oil of a first oil flowing amount flows from the lower chamber of each chamber to the upper chamber thereof when each piston descends according to opening of the door and oil of a second oil flow amount less than the first oil flow amount flows from the upper chamber thereof to the lower chamberthereofwheneachpistonascends accordingto closing of the door; and an elastic member which is installed in the lower-most lower chamber, for elastically supporting the lower-most piston.

In this case, the ascending and descending unit comprises: first and second vertical guide holes which are formed in positions facing the first guide vessel up and down; a camshaft which is rotatably installed in the inner circumference of the cylindrical first guide vessel, inwhich first and second ascending and descending guide holes having a respectively symmetrical spiral shape are penetratingly formed along the outer circumference of the cylindrical body of the camshaft and the upper portion of the cylindrical body thereof is connected with the shaft; and a guide pin whose both ends are coupled with first and second vertical guide holes via the first and second ascending and descending guide holes, respectively, and which is movably disposed up and down along the first and second ascending and descending guide holes according to relative rotation of the camshaft or the first to third guide vessels depending upon opening and closing of the door.

Also, it is preferable that the number of hydraulic circuits comprise a number of check valves which open and close selectively the first and second oil paths according to ascending and descending of the first and second pistons, to thereby increase and decrease an amount of oil which flows via the oil paths and thus control an ascending and descending speed of the first and second pistons.

The hinge apparatus according to the present invention further comprises a support bracket whose one end is fixed to the lower surface or upper surface of the hinge apparatus main body, and on the other end of which a shaft coupler is mounted; a serration portion which connects mutually between the shaft of the camshaft and the shaft coupler in the support bracket, and whose lower portion is coupled with the shaft coupler by screw, to thus adjust a zero-point; and a height adjustment bolt which is coupled with the lower portion of the shaft coupler and pushes up or down the serration portion according to rotational movement thereof in the up-and-down direction, to thereby adjust a set height of the door.

[Advantageous Effects]

As described above, the present invention provides a slim automatic return hinge apparatus which can maintain the whole outer shape to be simple when it is installed in one of various doors requiring for ultra small diameter, in which an outer diameter is compact so as to be buried in the inner portion of the door and can increase a damping force when a door is closed in which an additional oil closed circuit is extended and formed in addition to two oil closed circuits. [Description of Drawings]

The above andother objects andadvantages ofthepresent invention will become more apparent by describing the preferred embodiments thereof in detail with reference to the accompanying drawings in which: FIG. 1 is a lengthy cross-sectional view showing a slim automatic return hinge apparatus according to the present invention;

FIG. 2 is a perspective view of a first guide vessel for vertically guiding a guide pin in the hinge apparatus shown in FIG. 1;

FIG. 3A is a perspective view showing a camshaft for guiding a piston unit to move up and down according to opening and closing of a door in the slim hinge apparatus shown in FIG. 1; FIG. 3B is a diagram showing a relationship between a position of the guide pin and a compression state of a return spring according to operation of the hinge apparatus in an ascending and descending guide hole of the camshaft shown in FIG. 3A; FIG. 4 is a perspective view showing a piston unit in the slim hinge apparatus of FIG. 1;

FIG. 5 is a perspective view showing first and second valve actuators in the piston unit according to another embodiment of the present invention;

FIG. 6A is a cross-sectional view showing a piston unit and a return speed adjuster illustrating an initial position where first and second pistons of the piston unit are located at a top dead center, respectively;

FIG. 6B is a cross-sectional view illustrating an oil flow when the pistons in the first and second piston portions descend according to opening of the door, respectively; FIG. 6C is a cross-sectional view showing a piston unit and a return speed adjuster illustrating a state where first and second pistons of the piston unit are located at a bottom dead center, respectively;

FIG. 6D is a cross-sectional view illustrating an oil flow when the pistons in the first and second piston portions ascend according to closing of the door, respectively;

FIG. 6E is a cross-sectional view of a piston unit and a return speed adjuster showing a state where the first and secondpistons in thepistonunit returnto an initial position located at a top dead center, respectively, when an opening angle of a door reaches O°according to closing of the door;

FIG. 7 is an enlarged partial cross-sectional view illustrating an operation of the valve actuator at a portion

"A" shown in FIG. 6A; FIG. 8 is a cross-sectional view schematically showing aninstallationstructurewhenthe slimautomaticreturnhinge apparatus according to the present invention is applied to the lower portion of a refrigerator; and

FIG. 9 is a perspective view schematically showing another installation structurewhenthe slimautomatic return hinge apparatus accordingtothepresent inventionis applied to the lower portion of a refrigerator. [Best Mode]

Hereinbelow, a slim automatic return hinge apparatus according to a preferred embodiment of the present invention willbe describedwith reference to the accompanyingdrawings . Like reference numerals denote like elements through the following embodiments.

Referring to FIGs. 1 to 4, the whole configuration of a slim automatic return hinge apparatus according to the present invention will be described below. In general, an automatic return hinge apparatus is divided into a shaft fixedmethod and a housing fixed method. In the shaft fixed method, a rotational shaft, that is, a camshaft in the present invention is fixed to a door frame or a door, and then a housing, that is, a guide vessel in the present invention is rotated according to rotation of the door. Meanwhile, in the housing fixed method, a housing is fixed to a door frame and a rotational shaft is rotated according to rotation of a door.

The automatic return hinge apparatus according to the present invention can be applied to any one of the shaft fixed method and the housing fixed method. In the following embodiment, a hinge apparatus adoptinga housing fixedmethod where a housing is fixed to a frame will be described as an example.

First, a slim automatic return hinge apparatus according to the present invention includes first through third guide vessels 10, 20 and 30 which play a role of a housing, respectively. The first through thirdguide vessels 10, 20 and 30 are sequentially detachably connected with one another in lengthy direction. A camshaft 40 which is mutually connected by a guide pin 45 is disposed in the inner side of the first guide vessel 10, and a piston unit 50 the upper end of which is penetrated and connected by the guide pin 45 is disposed in the inner sides of the second and third guidevessels 20 and30 soas tomovetogetherwiththe camshaft 40 (see FIG. 4) . In this case, the lower end of the piston unit 50 is elastically supported by one end of a return spring 60. The other end of the return spring 60 is supported by a sealing cap 70 which seals an opening end of the third guide vessel 30. The hinge apparatus according to the present invention having the above-described configuration will be described in more detail.

Referring to FIG. 2, the first guide vessel 10 which is formed in a cylindrical shape includes first and second guide holes 11 and 12 which are formed in an up/down direction atpositions facing each other and an insertionhole 10a formed in the upper-inner side of the first guide vessel 10. Also, referring to FIG. 3A, the camshaft 40 includes a cylindrical body 40a in which first and second ascending and descending guide holes 41 and 42 of a respectively substantially spiral pattern with a 180°movable symmetrical structure are penetrated and formed around the ^' outer circumference of the camshaft 40. Also, the lower end of the shaft 40b is integrally fixed and connected with the inner circumference of the upper end of the cylindrical body 4Oabyaweldandso on. Theupperendofthe shaft 4Obprotrudes through the insertion hole 10a in the first guide vessel 10.

In this case, when a rotational shaft of a door is same as that of a door frame as shown in FIG. 8, the shaft 40b of the camshaft 40, for example, the first through third guide vessels 10, 20, and 30 can be buried into a rotating door. In this embodiment, a hinge apparatus adopting a housing fixed method will be described as an example.

When a door is rotated, a rotational force is applied to the shaft 40b, to thus make the shaft 40b rotate. Also, since a repulsive force of a return spring 60 elastically supporting the piston unit 50 is applied between a step 10b of the first guide vessel 10 and the cylindrical body 40a of the camshaft 40, a pair of thrust bearings 81 and 82 are inserted between the camshaft 40 and the first guide vessel 10 in order to reduce a rotational friction and noise when the camshaft 40 rotates.

Further, both ends of the guide pin 45 which moves up anddownaccording to rotation of the camshaft 40 are inserted into the pair of first and second ascending and descending guide holes 41 and 42 formed on the outer circumference of the cylindrical body 40a of the camshaft 40 and the pair of vertical guide holes 11 and 12 formed in the first guide vessel 10, respectively.

Here, the guide pin 45 is penetratingly coupled with a coupling hole 51a in the piston unit 50, so that the piston unit 50 moves up and down together with the guide pin 45 according to the up/down movement of the guide pin 45.

It is also possible to install a pair of bearings (not shown) in both ends of the guide pin 45 so that a partial wear is prevented together with reduction of friction/noise whentheguidepin45moves alongthe first and secondascending and descending guide holes 41 and 42 of the camshaft 40 and the vertical guide holes 11 and 12 of the guide vessel 10.

Meanwhile, the second and third guide vessels 20 and

30 include isolators 20b and 20b which are formed in the upper portions thereof, and first and second chambers 21 and 22; and 32 and 32 which are independently partitioned below the isolators 20b and 30b.

Meanwhile, as shown in FIGs. 1 and 4, the piston unit 50 includes a first piston rod 51 and a first piston 53, and a second piston rod 55 and a second piston 57. The first and second piston rods 51 and 55 are slidably coupled with the inner circumferences of the insertion holes 20a and 30a, respectivelyandthus ascendanddescendaccordingtorotation of the camshaft 40.

Here, the inner space of the second guide vessel 20 is partitioned into first upper and lower chambers 21 and

22 by the first piston 53. Likewise, the inner space of the third guide vessel 30 is partitioned into second upper and lower chambers 31 and 32 by the second piston 57.

Meanwhile, the first piston rod 51 is penetratingly- coupled with a coupling hole 51a by the guide pin 45. The outer circumference of the first piston rod 51 is slidably penetratingly coupled with the insertion hole 20a of the isolator 20b. A first recess 51b is formed in the lower-center of the first piston rod 51. Further, a first oil path is formed which includes a pair of first communication holes 51c and 51dwhichpenetratethe outercircumferenceofthe firstpiston rod 51 in a direction perpendicular with the first recess 51b.

Also, the first piston 53 which partitions the inner space of the second guide vessel 20 into first upper and lower chambers 21 and 22 is integrally formed in the lower end of the first piston rod 51. The first piston 53 communicates with the first recess 51b at the center of the first piston 53, and includes a first central throughhole 53a which is detachably coupled with the upper end of the second piston rod 55 by a screw. Meanwhile, the outer circumference of the secondpiston rod 55 is slidably penetratingly coupled with the insertion hole 30a in the isolator 30b. Further, a second recess 55a is formed at the upper-center of the second piston rod 55. Also, a pair of second communication holes 55b and 55c are formed which penetrate the outer circumference the second piston rod 55 in a direction perpendicular with the second recess 55a, respectively. The second recess 55a and the pair of second communication holes 55b and 55c form a second oil path.

In this case, a space of a predetermined height is formed between the upper end of the second piston rod 55 and a step 53b of a central throughhole 53a in the first piston 53. A first valve actuator 54 of a circular plate shape is disposed in the space so as to move up and down.

The first valve actuator 54 is formed in diameter larger than those of the first and second recesses 51b and 55a, and slightly smaller than that of the first central throughhole

53a. Also, a small-sized throughhole 54a through which oil passes is formed at the center of the first valve actuator

54. Also, as shown in FIG. 7, a number of oil path grooves

52 through which oil passes are formed in the first recess 51b.

The first valve actuator 54, the first central throughhole 53a, and the number of oil path grooves 52 play a role of a check valve 65a for controlling an amount of oil mutually flowing in the upper/lower chambers 21 and 22 of the first chamber according to ascending and descending of the first piston 53 when a door is opened and closed.

That is, in the case that the first piston 53 descends according to opening of the door, the first valve actuator 54 is pushed up by oil moving from the first lower chamber 22 via the second oil paths 55a, 55b, and 55c, to the first oil paths 51b, 51c, and 51d and then ascends. Here, oil flows outbetweentheoutercircumferenceofthe firstvalve actuator 54 andtheinnercircumferenceofthe first centralthroughhole 53b and the throughhole 54a and moves to the first oil paths 51b, 51c, and 51d. Then, if the first recess 51b is closed by the ascending first valve actuator 54, oil flows in the first upper chamber 21 via the first oil path after having passed though the number of oil path grooves 52 and the throughhole 54a.

Reversely, that is, in the case that a door is closed and the first piston 53 ascends, the first valve actuator 54 is pushed down by oil moving from the first upper chamber

21 via the first oil paths 51b, 51c, and 51d, to the second oil paths 55a, 55b, and 55c and then descends. Here, oil flows outbetweentheoutercircumferenceofthe firstvalve actuator 54 andthe innercircumferenceofthe first central throughhole 53b and the throughhole 54a and moves to the second oil paths 55a, 55b, and 55c, as in the case that the door is opened. Then, if the second recess 55a is closed by the descending first valve actuator 54, oil flows in the first lower chamber

22 via the second oil path only after having passed though the throughhole 54a.

Accordingly, an amount of oil which is abruptly reduced in comparison with an amount of oil which has moved from the first lower chamber to the first upper chamber at the time when the first piston descends moves from the upper chamber to the lower chamber. Thus, the check valve 65a controls an amount of oil moving between the upper and lower chambers, to thus control a closing speed of the door.

Meanwhile, a third recess 55d is formed at the lower-center of the second piston rod 55. Also, a pair of third communication holes 55e and 55f are formed which penetrate the outer circumference the second piston rod 55 in a direction perpendicular with the third recess 55d, respectively. The third recess 55d and the pair of third communication holes 55e and 55f form a third oil path.

Also, the second piston 57 which partitions the inner space of the third guide vessel 30 into second upper and lower chambers 31 and 32 is detachably coupled with the lower end of the second piston rod 55 by a screw.

Meanwhile, a second central throughhole 57a having a step 57bwhich communicates with the third recess 55d is formed at the center of the second piston 57. Also, an extension hole 57c having a diameter smaller than that of the second central throughhole 57a is formed in one end of the second central throughhole 57a. In this case, the extension hole 57c forms a fourth oil path.

Here, like the checkvalve 65a formed in the first piston 53, a second valve actuator 56 is positioned in a space between the step 57b andthe secondcentral throughhole 57a. The second valve actuator 56 is slightly smaller than that of the second central throughhole 57a in diameter, and larger than those of the third recess 55d and the extension hole 57c. A throughhole 5βa is formed at the center of the second valve actuator 56. Like the first recess 51b shown in FIG. 7, a number of oil path grooves (not shown) are formed in the inner circumference of the third recess 55d.

Accordingly, the second valve actuator 56, the number of oil path grooves 52, and the throughhole 56a form a check valve 65b playing the same function and role of the check valve 65a formed in the first piston 53.

Thus, the hinge apparatus according to the present invention accomplishes two independent hydraulic circuits in the inner spaces of the second and third guide vessels 20 and 30, to thus maintain a large damping force which can adjust a door closing speed, and reduce a diameter of the whole hinge apparatus into a slim type hinge apparatus. As a result, the hinge apparatus according to the present invention can be buried into a door.

Meanwhile, in order to prevent leakage of oil filled in the first and second upper and lower chambers 21 and 22; and 31 and 32, a number of O-rings 91, 92, 93 and 94 are incorporated in the hinge apparatus. That is, the positions of the O-rings are the inner side 91 of the insertion hole 20a, the upper-outer side 92 of the first piston 53, the inner side 93 of the insertion hole 30a, and the outer side 94 of the second piston 57, as shown in FIG. 1.

Also, a sealing cap portion 70 coupled with the lower-inner side of the third guide vessel 30 includes a sealing cap 71 on the outer circumference of which an 0-ring 95 is coupled in order to prevent leakage of oil filled in the third guide vessel 30, an air discharge bolt 73 coupled with the sealing cap 71, and a cover 75 coupled with the lower end of the third guide vessel 30 by a screw in order to support the sealing cap 71.

In this embodiment, the first and secondvalve actuators 54 and 56 of the first and second check valves 65a and 65b have been described with respect to the circular plate shaped valve actuators. However, as shown in FIGs. 5A and 5B, first and second valve actuators 154 and 156 of a ball type can be used. Also, it is possible that oil path grooves 154a and 154b playing a role of throughholes 54a and 54b in the first and second valve actuators 54 and 56 are formed in the upper end of the second recess of the second piston rod 55 and the upper end of the extension hole 57c linked with the step 57b of the second piston 57.

Hereinbelow, an ascending and descending guide structure of the piston according to the present invention will be described with reference to FIGs.3A and 3B in detail.

FIG. 3A is a perspective view showing a camshaft for guiding a piston unit to move up and down according to opening and closing of a door in the slim hinge apparatus shown in FIG.1, and FIG.3B is a diagramshowing a relationshipbetween a position of the guide pin and a compression state of a return spring according to operation of the hinge apparatus in an ascending and descending guide hole of the camshaft shown in FIG. 3A.

The first and second ascending and descending guide holes 41 and 42 in the camshaft 40 are divided into four sections a, b, c, and d which varies according to a door opening angle as shown in FIG. 3B. That is, the four sections are a first section "a" between a door opening angle of 0° to 15% a second section "b" between a door opening angle of 15° to 90°, a third section "c" between a door opening angle of 90° to 130°, and a fourth section "d" between a door opening angle of 130° to 160°.

The first section "a" is at a state of a hydraulic circuit of FIG. 6D to be described later when a door automatically returns, and has a damping force which can close a door against an elasticity of a latch due to movement of oil. In this case, a cam diagram angle "CL " of the first and second ascending and descending guide holes 41 and 42 is set in the range of 45°to 65°relatively larger than an angle of "β " of the second section "b" to thus increase an efficiency at the time of ascending a piston and thereby compensate for a loss of a closing force due to lowering of the resistance of the hydraulic circuit and a proportional restoring force of the return spring 60.

As a result, although a compression spring is used without using a torsion spring as a return spring at the time of automatically returning a door, a perfect return, that is, a complete locking, to an initial position of a door can be accomplished.

The secondsection "b" isata stateofahydrauliccircuit of FIG. 6C to be described later when a door automatically returns. When the door is opened, a restoring force of the return spring 60 is increased inproportionwith a door opening angle, and thus a force necessary for a user to open the door is also increased in proportion with a door opening angle.

Thus, in the second section "b," a cam diagram angle "β " of the first and second ascending and descending guide holes 41 and 42 is set in the range of 10° to 45° relatively smaller than an angle "α " of the first section "a" to thereby increase a rotational efficiency of the camshaft 40 proportionally when a door is opened and thus compensate for an opening force increase portion which increases in proportion with opening of the door.

Also, in the third section "c, " a cam diagram angle of the first and second ascending and descending guide holes 41 and 42 is set zero, and thus interrupts an automatic return by the return spring 60. In the third section "c, " an angle where the door has been opened is maintained, and a restoring force of the return spring 60 becomes the largest.

The fourth section "d" is slantingly formed upwards from the third section "c, " and is a stopping force reinforcement section where the guide pin 45 does not move due to a hook.

Meanwhile, the cam diagram angle can be formed of a slope of 30° to 45°in the first section "a" of the ascending and descending guide holes 41 and 42. In the case that the slope of the first section "a" is formed of 30° to 45°, a distance of ascending and descending the piston unit 50 connected with the guide pin 45 is short. Accordingly, an efficiency of the return spring 60 to be compressed becomes low in comparison with an external force which rotates the camshaft 40.

Therefore, inthe case that the slope ofthe first section "a" is 30° to 45°, an impact of a door which is closed by an external force such as an inertial force is absorbed in the door which is opened and closed up and down and thus the door can be slowly closed.

Also, in the case that the slope of the first section "a" is 45° to 65°, an ascending and descending distance of the piston unit 50 becomes long, and thus a repulsive force of the return spring 60 which is compressed becomes larger than an external force which rotates the camshaft 40. Thus, in the case that the slope of the first section "a" is 45° to 65°, an efficiency of the return spring 60 increases and thus a door which is opened and closed left and right can be swiftly and more easily closed into a complete return position.

As described above, in the case that the cam diagram angle is set in the ascending and descending guide holes 41 and 42, the guide pin 45 descends along an ascending and descending guide 41a in the ascending and descending guide holes 41 and 42 which are sloped up and down in the first and second sections "a" and "b, " and does not move up and down and temporally stops in the third section "c." Also, in the case that the camshaft 40 continues to rotate, the guide pint 45 proceeds to the fourth section "d" which is slightly slanted upwards from the third section "c, " and the guide pin 45 is caught by a first stopper 41b and does not rotationally move and stops.

Also, the first stopper 41c and a third cam diagram sustenance portion 41f are formed as a slope of 15° to 60° in the fourth section "d" of the ascending and descending guide holes 41 and 42. In the case that the slope of the fourth section "d" is less than 15°, the camshaft 40 easily rotates due to the repulsive force of the return spring 60 or a feeble external force. Accordingly, it is inappropriate since a force of stopping the guide pin 45 is feeble.

Also, in the case that the slope of the fourth section "d" exceeds 60°, a forceofstoppingtheguidepin45 is enhanced due to the stopping force of the first stopper 41b. However, in the case that the guide pin 45 proceeds from the fourth section "d" to the third section "c," that is, the guide pin 45 ascends, it is not appropriate since a large amount of an external force is needed.

Meanwhile, in the case that the guide pin 45 ascends due to the repulsive force of the compressed return spring 60, an oil pressure at the upper portion of the piston unit 50 is applied greater than the elastic force of the return spring 60 at a limit boundary where the piston unit 50 can ascend. Accordingly, the piston unit 50 can abruptly descend in a reverse direction.

Also, the guide pin 45 can generate internal noise and damage internal components due to irregular movement at the initial time when the guide pin 45 proceeds from the third section "c" to the second section "b." To prevent this, it is preferable that a boundary portion between a first cam diagram sustenance portion 4Id and a second cam diagram sustenance portion 41e in the ascending and descending guide holes 41 and 42 is formed as a curved surface.

Also, the first cam diagram sustenance portion 41d and the second cam diagram sustenance portion 41e are formed to have respectively opposing curved surfaces at a certain interval with respect to a first ascending and descending guide hole 41a.

Hereinbelow, the entire operation of the slim automatic return hinge apparatus according to the present invention will be described with reference to FIGs. 6A to 6E. FIG. 6A is a cross-sectional view showing a piston unit and a return speed adjuster illustrating an initial position where first and second pistons of the piston unit are located at a top dead center, respectively. FIG. 6B is a cross-sectional view illustratinganoil flowwhenthepistons in the first and second piston portions descend according to opening of the door, respectively. FIG. 6C is a cross-sectional view showing a piston unit and a return speed adjuster illustrating a state where first and second pistons of the piston unit are located at a bottom dead center, respectively. FIG. 6D is a cross-sectional view illustrating an oil flow when the pistons in the first and second piston portions ascend according to closing of the door, respectively. FIG. 6E is a cross-sectional view of a piston unit and a return speed adjuster showing a state where the first andsecondpistons inthepistonunit returnto aninitial position located at a top dead center, respectively, when an opening angle of a door reaches 0° according to closing of the door.

In the case of the slimautomatic return hinge apparatus according to the present invention, when a door is opened, a hydraulic circuit of FIG. 6B is set. That is, in the case of the slim automatic return hinge apparatus 100 according to the present invention, when a dorr is opened, an external rotational force is transferred to the shaft 40b of the camshaft 40. Accordingly, the internal components operate as follows. If a user opens a door at an initial state of FIG. 6A where the door is closed, a rotational force of a left-hand screw direction is transferred to the camshaft. Accordingly, the guide pin 45 whose both ends are inserted into a pair of ascending and descending guide holes 41 and 42 and a pair of vertical guide holes 11 and 12 in the first guide vessel 10 moves downwards along the ascending and descending guide holes 41 and 42 according to rotation of the camshaft 40. In this case, as shown in FIG. 6B, a force which intends to move downwards is applied to the first and second pistons 53 and 57 which move together with the guide pin 45 and the first and second piston rods 51 and 55. Accordingly, oil positioned at the lower side of the first piston 53, that is, the second lower chamber 32 rises up when the first valve actuator 54 makes the second recess 55a opened. Thus, oil passes through the second oil paths 55a, 55b, and 55c, and then passes through sequentially an intermediate portion between the outer circumference of the first valve actuator 54 and the first central throughhole 53a, the throughhole 54a, and the first oil paths 51b, 51c, and 51d, and easilymoves to the upper side of the first piston 53, that is, the first upper chamber 21. In this case, the first valve actuator 54 is pushed and raised up by oil to thus close the first recess 51b, and the oil flows in the first upper chamber 21 via a number of oil path groove 52.

Simultaneously, oil positioned at the lower side of the second piston 57, that is, the second lower chamber 32 passes through the fourth oil path 57c, an intermediate portion between the outer circumference of the second valve actuator 56 and the second central throughhole 57a, the throughhole 5βa, and the third oil paths 55d, 55e, and 55f, in sequence, and moves to the upper side of the second piston 57, that is, the second upper chamber 31.

Likewise, in this case, the second valve actuator 56 is pushed and raised up by oil to thus close the third recess 55d, and the oil flows in the second upper chamber 31 via a number of oil path groove 52.

Thus, the guide pin 45 moves between the first and second sections "a" and "b" as in the operational state in the ascending and descending guide holes 41 and 42 shown in FIG.

3B, and the piston unit 50 compresses the return spring 60 and descends.

Also, in the case that the camshaft 40 continues to rotate, the guide pint 45 reaches the third section "c" and restrictively moves by the first stopper 41b in the third section "c" of the ascending and descending guide holes 41 and 42. Accordingly, as shown in FIG. 6C, the piston unit

50 is maintained as a stop state at a state where the first and second pistons 53 and 57 are located at a bottom dead center.

Meanwhile, if a user closes a door within a door opening angle below 90°or opens and closes within a door opening angle below 90°, the hinge apparatus according to the present invention performs an automatic return operation of the door when the door is closed.

When a door opening angle is 90°, that is, is in a stop state, if a user rotates the door so that a small amount of an external force of a right-hand screw direction is transferredto the camshaft 40, the guidepin 45passes through the first stopper 41b and is beyond the third section "c."

Then, the piston unit 50 starts to move upwards due to a repulsive force of the compressed return spring 60, and the guide pin-45 connected with the piston unit 50 also rises upalongthe second section "b" ofthe ascending anddescending guide holes 41 and 42, that is, the ascending and descending guide 41a of a slow sloped angle of 10 to 45°. As a result, the camshaft 40 rotates in the right-hand screw direction and intends to make a door return to an initial position.

Here, the oil in the first and second upper chambers

21 and 31 in the first piston 53 moves from the first and second upper chambers 21 and 31 to the first and second central throughholes 53a and 57a, respectively, via the first oil paths 51b, 51c, and 51d and the third oil paths 55d, 55e, and 55f by the first and second pistons 53 and 57 which rise up as shown in FIG. 6D.

Then, the first valve actuator 54 is safely seated in the upper end of the second piston rod 55 by the oil having flown via the first oil paths 51b, 51c, and 51d, and thus closes the secondrecess 55a. Simultaneously, the secondvalve actuator 56 is safely seated in the step 57b of the second piston 57 by the oil having flown via the third oil paths 55d, 55e, and 55f, and thus closes the extension hole 57a.

Accordingly, the secondandfourthoilpathsare isolated by the first and second valve actuators 54 and 56, and thus the oil on the upper portions of the first and second pistons

53 and 57 moves to the first and second lower chambers 22 and 32 only via the throughholes 54a and 56a of the first and second valve actuators 54 and 56, respectively, until a door opening angle reaches 15° from 90°. Thus, anamount ofa secondoil flowat thetimeofclosing a door is greatly reduced in comparison with an amount of a first oil flow at the time of opening the door, and thus the piston unit 50 slowly rises up at a state of maintaining a damping force.

In this case, the guide pin 45 connected with the piston unit 50 rises up along the second section "b" of the ascending and descending guide holes 41 and 42, that is, the ascending and descending guide 41a of a slow sloped angle. The slowspeedrise-upofthepistonunit 50 ismaintained until the door opening angle reaches 15°, and thus a user can avoid a safety accident or inconveniences due to an abrupt or sudden return of a door.

Thereafter, inthe case that a door opening angle reaches 15° as shown in FIG. 3B, the guide pin 45 connected with the piston unit 50 starts to rise up along the ascending and descending guide 41a which is set at an abrupt slope in the first section "a" of the ascending and descending guide holes 41 and 42, that is, from 45° to 65°. Thus, when a door opening angle ranges from 15° to 0°, a hydraulic circuit is set in the same manner as that of when the door opening angle ranges from 90° to 15°. However, a sloped angle of the ascending and descending guide 41a is set relatively larger than that of the second section "b." As a result, a restoring force of the return spring 60 is reduced, but a frictional resistance of the ascending and descending guide 41a is reduced. Accordingly, an ascending speed of the piston unit 50 is accelerated. Thus, the door returns to the initial position and becomes a locking state by means of a latch of the door. Also, the first and second pistons 53 and 57 return to the initial positions as shown in FIG. 6E.

As described above, the hinge apparatus according to the present invention includes two independent oil closed circuits formed in the lengthy direction. Also, the hinge apparatus according to the present invention performs an automatic return operation at a state where a damping force is sufficiently maintained by the check valves 65a and 65b which simultaneously operate according to ascending and descending of the piston unit 50 in the closed circuit, respectively. As a result, the hinge apparatus according to the present invention is formed in size of a compact diameter so as to be buried into a door. Simultaneously, the hinge apparatus according to the present invention can solve the problem that a restoring force of the return spring is reduced and thus the door is not completely closed, in the case that a door gains access to the initial position during performing an automatic return operation.

Further, independent closed hydraulic circuits including guide vessels having a piston rod and a piston therein as in the second guide vessel, a pair of chambers divided by the pistons, and oil paths through which oil can flow in between the chambers, can be sequentially installed in the present invention. In this case, the piston rod is configured to move together with the piston unit.

Thus, thepresent inventioncaneasilycontrol adamping force, that is, a door closing speed, by adding the independent closed hydraulic circuits as described above.

FIG. 8 is a cross-sectional view schematically showing aninstallationstructurewhentheslimautomaticreturnhinge apparatus according to the present invention is applied to the lower portion of a refrigerator. The hinge apparatus 100 according to the present invention having the above-described configuration has a structure that the first through third guide vessels 10, 20, 30 are inserted into a door 3 of a refrigerator 1, and a shaft 40b is inserted into and fixed to a coupler 5a of a support bracket 5 in the refrigerator, to thereby make the first through third guide vessels 10, 20, and 30 rotate according to rotation of the door 3.

FIG. 9 is a perspective view schematically showing another installation structure whenthe slimautomatic return hinge apparatus accordingto thepresent inventionis applied to the lower portion of a refrigerator.

Meanwhile, it has been described with respect to the type that the shaft 40b of the hinge apparatus 100 according to the present invention is fixed directly to the coupler 5aofthebracket 5. However, inadditiontothat, it ispossible that a serration 91 is disposed between the shaft 40b and the coupler 5a in order to set an accurate position of the shaft 40b, or set a zero point of the cam diagram at a desired place.

In this case, the shaft 40b is mutually fixed by a spring pin 93 at a state where the shaft 40b has been inserted into the upper portion of the serration 91. Moreover, a lower outer circumferential gear portion 91a is tooth-engaged with an inner circumferential gear portion 5b of the coupler 5a in the bracket 5.

Further, a push bolt 97 which can prevent a gap between the inner and outer circumferential gear portions 5b and 91a by pushing the outer circumferential gear portion 91a in the coupled serrationtowardone side of the inner circumferential gear portion 5b is coupled with one side of the coupler 5a in the bracket 5. Also, a height adjustment bolt 95 which can push up or down the hinge apparatus of a door at a state of contacting the lower end of the serration 91 to thereby adjust height of the door 3, is coupled with the lower side of the coupler 5a in the bracket 5 in the axial direction of the hinge apparatus.

Accordingly, if the height adjustment bolt 95 rotationally moves in the direction of the serration 91, the serration 91 moves upwards along the inner and outer circumferential gear portions 5b and 91a by the height adjustment bolt 95. Finally, the hinge apparatus 100 and the door 3 ascend simultaneously. In the case that the height adjustment bolt 95 is rotated reversely, the door 3 descends and thus can be easily set at a proper height.

Meanwhile, it is also possible to modify the serration 91 and the coupler 5a into a key and groove coupling pattern. That is, instead of the outer circumferential gear portion and the inner circumferential gear portion of the coupler, a keygroove is formedinthe inner circumference ofthe coupler along the axial direction, and a key is projectingly installed ontheoutercircumferenceinthelowerportionofthe serration in correspondence to the key grooves, to then mutually couple the key groove and the key. By doing so, it is also possible to reduce a gap between the serration and the coupler to thus provide an accurate rotational angle for the hinge apparatus .

Further, the slim automatic return hinge apparatus according to the present invention can be mounted in a door using a bracket whose one end is fixed to the upper portion of the first guide vessel 10 and other end is fixed to the door, in addition to the embodiment shown in FIGs. 8 and 9.

Also, the slim automatic return hinge apparatus according to the present invention has been described with respect to the case that the rotational axis of a hinge apparatus is same as that of a door. However, it can be also applied to the case that the rotational axis of a hinge apparatus is not same as that of a door, using a driving link and a driven link.

Meanwhile, in the above-described embodiments, a check valve determining an automatic return speedof a door is formed in a coupling portion between a piston and a piston rod, to thus determine the automatic return speed of the door as a predetermined single speed. However, it is also possible to adjust an automatic return speed of a door by a multiple step, in the present invention, in which a check valve is installed in a place other than the center of a piston, an oil path is formed at the center of a piston rod, and an amount of oil flowing according to an ascending level of the piston is controlled by a structure where a control rod is inserted into the oil path.

[Mode for Invention]

As described above, the present invention has been describedwithrespecttoparticularlypreferredembodiments.

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 tomake various modifications andvariations, without departing off the spirit of the present invention.

Thus, the protective scope of the present invention is not definedwithinthe detaileddescriptionthereofbut is defined by the claims to be described later and the technical spirit of the present invention.

[industrial Applicability]

As described above, a slim automatic return hinge apparatus according to the present invention can be applied to the inner sides of a variety of doors requiring for an ultra-slim diameter, respectively, as a burial or exposure type.

Claims

[CLAIMS]

[Claim l]

An automatic return hinge apparatus comprising: a cylindrical first guide vessel in which first and second vertical guide holes are formed up and down in positions facing each other; a cylindrical second guide vessel in which the upper side of a first isolator is detachably coupled with the lower end of the cylindrical first guide vessel and a first chamber isolated from the cylindrical first guide vessel is provided in the lower side of the first isolator; a cylindrical third guide vessel in which the upper side of a second isolator is detachably coupled with the lower end of the second cylindrical guide vessel and a second chamber isolated from the first chamber of the cylindrical second guide vessel is provided in the lower side of the second isolator; a camshaft which is rotatably installed in the inner circumference of the cylindrical first guide vessel, inwhich first and second ascending and descending guide holes having a respectively symmetrical spiral shape are penetratingly formed along the outer circumference of the cylindrical body of the camshaft so that the first and second ascending and descending guide holes can be moved with respect to each other, and a shaft protrudes so that the upper end of the cylindrical body thereof penetrates the upper end of the first guide vessel; a guide pin whose both ends are coupled with first and secondvertical guideholes viathe first and secondascending and descending guide holes, respectively, and which is movably disposed up and down along the first and second ascending and descending guide holes according to relative rotation of the camshaft or the first to third guide vessels depending upon opening and closing of a door; first and second piston rods whose upper ends are sequentially coupled with the guide pin and lower ends are extended to a second chamber via the first chamber, so as to slide up and down along the inner circumference of the first and second isolators of the first and second guide vessels; first and secondpistons which are coupledwiththe first and second piston rods, respectively, in which the first and second chambers are partitioned into the upper and lower portions, respectively, and which includes first and second oil paths through which oil in the first and second chambers flows in the upper and lower chambers; first and second check valves which open and close selectively the first and second oil paths according to ascending and descending of the first and second pistons, to thereby increase and decrease an amount of oil which flows via the oil paths and thus control an ascending and descending speed of the first and second pistons; a sealing cap which is detachably coupled with the lower end of the third guide vessel at a sealed state; and an elastic member which is installed between the second piston and the sealing cap, and which provides a restoring force which is compressed according to opening of the door and raises the second piston according to closing of the door.

[Claim 2]

The automatic returnhinge apparatus accordingto claim

1, further comprising at least one hydraulic circuit in order to increase a damping force of the hinge apparatus. [Claim 3]

The automatic returnhinge apparatus accordingto claim

2, wherein the hydraulic circuit comprises a guide vessel which is insertedbetween the second and third guide vessels, having an independent chamber therein, a piston which is slidably inserted into the chamber, and a piston rod which connects between the first and second pistons. [Claim 4]

The automatic returnhinge apparatus accordingto claim 1, wherein the first oil path communicates with the upper portion of the first chamber via a first recess formed at the lower-center of the first piston rod, and communicates with the lower portion of the first chamber via a second recess formed at the upper-center of the second piston rod, and wherein the second oil path communicates with the upper portion of the second chamber via a third recess formed at the lower-center of the second piston rod, in which the lower portion of the second oil path communicates with the lower portion of the second chamber. [Claim 5]

Theautomatic returnhinge apparatus accordingto claim 4, wherein the first and second check valves employ circular or spherical valve actuators which are inserted into the first and second oil paths, respectively, to thus control an amount ofoil flowing selectivelybetweentheupperandlowerportions of the first and second chambers.

[Claim β] Theautomatic returnhinge apparatus accordingto claim 1, wherein the first and second ascending and descending guide holes include at least a first ascending and descending sectionof adooropeningangle of 0° to 15°, a secondascending and descending section of a door opening angle of 15° to 90°, and a stoppage section of a door opening angle of 90° to 130°, respectively. [Claim 7]

Theautomatic returnhinge apparatus accordingto claim

1, further comprising: a support bracket whose one end is fixed to the lower surface or upper surface of the hinge apparatus main body, and on the other end of which a shaft coupler is mounted; a serration portion which connects mutually between the shaft of the camshaft and the shaft coupler in the support bracket, and whose lower portion is coupled with the shaft coupler by screw, to thus adjust a zero-point; and a height adjustment bolt which is coupled with the lower portion of the shaft coupler and pushes up or down the serration portion according to rotational movement thereof in the up-and-down direction, to thereby adjust a set height of the door. [Claim 8]

Theautomaticreturnhingeapparatus accordingto claim 1, wherein the guide pin is moved up and down along the first and second ascending and descending guide holes according to relative rotation of the first through third guide vessels at the shaft of the camshaft depending upon opening and closing the door, in which the guide pin is buried into the inner portion of the door. [Claim 9]

An automatic return hinge apparatus comprising: a shaft; a cylindrical first guide vessel which rotatably supports the shaft with respect to the inner circumference thereof; a number of guide vessels which are sequentially detachably coupled with the lower side of the first guide vessel, and which includes an isolator in the upper sides thereof and a number of independent chambers provided below the isolator; an ascending and descending unit which is installed in the inner circumference of the first guide vessel and makes the guidepinsmoveupanddownbya rotationalmoment occurring in the shaft or the first guide vessel when a door rotates; a number of hydraulic circuits including piston rods which are inserted into the number of guide vessels, whose upperportions areconnectedwiththeguidepinintheascending and descending unit, and which ascend and descend according to ascending and descending of the guide pins, and a number of pistons which are coupled mutually with the piston rods at certain intervals and partition the number of chambers up and down, respectively, in which oil of a first oil flowing amount flows from the lower chamber of each chamber to the upper chamber thereof when each piston descends according to opening of the door and oil of a second oil flow amount less than the first oil flow amount flows from the upper chamber thereof to the lower chamber thereof when eachpiston ascends according to closing of the door; and an elastic member which is installed in the lower-most lower chamber, for elastically supporting the lower-most piston.

[Claim 10]

Theautomatic returnhinge apparatus accordingto claim 9, wherein the ascending and descending unit comprises: first and second vertical guide holes which are formed in positions facing the first guide vessel up and down; a camshaft which is rotatably installed in the inner circumference of the cylindrical first guide vessel, inwhich first and second ascending and descending guide holes having a respectively symmetrical spiral shape are penetratingly formed along the outer circumference of the cylindrical body of the camshaft and the upper portion of the cylindrical body thereof is connected with the shaft; and a guide pin whose both ends are coupled with first and secondvertical guideholes via the first and secondascending and descending guide holes, respectively, and which is movably disposed up and down along the first and second ascending and descending guide holes according to relative rotation of the camshaft or the first to third guide vessels depending upon opening and closing of the door. [Claim 11]

Theautomaticreturnhinge apparatus accordingto claim 9, wherein the number of hydraulic circuits comprise a number of check valves which open and close selectively the first and second oil paths according to ascending and descending of the first and second pistons, to thereby increase and decrease an amount of oil which flows via the oil paths and thus control an ascending and descending speed of the first and second pistons.

[Claim 12] A hinge apparatus for automatically returning a door when the door is closed, the hinge apparatus comprising: a cylindrical first guide vessel in which first and second vertical guide holes are formed up and down in positions facing each other; a camshaft which is rotatably installed in the inner circumference of the cylindrical first guide vessel, inwhich first and second ascending and descending guide holes having a respectively symmetrical spiral shape are penetratingly formed along the outer circumference of the cylindrical body of the camshaft so that the first and second ascending and descending guide holes can be moved with respect to each other, and a shaft protrudes so that the upper end of the cylindrical body thereof penetrates the upper end of the first guide vessel, and the camshaft is rotated by a relative external force applied to the first guide vessel via the shaft when the door is rotated; a guide pin whose both ends are coupled with first and secondvertical guide holes via the first and second ascending and descending guide holes, respectively; a cylindrical second guide vessel in which the upper side of a first isolator is detachably coupled with the lower end of the cylindrical first guide vessel, the lower end of the camshaft is supported by the upper end of the first isolator and a first chamber isolated from the cylindrical first guide vessel is provided in the lower side of the first isolator; a cylindrical third guide vessel in which the upper side of a second isolator is detachably coupled with the lower end of the second cylindrical guide vessel and a second chamber isolated from the first chamber of the cylindrical second guide vessel is provided in the lower side of the second isolator; a first piston rod whose upper end penetrates the guide pin, whose outer circumference is slidably penetratingly coupled with the upper end of the second guide vessel, and on the lower-center of which a first recess communicating with the first upper chamber is formed; a first piston which is integrally formed in the lower end of the first piston rod, whose outer circumference is slidably coupled along the inner circumference of the second guide vessel, and on the lower-center of which a first central throughhole communicating with the first recess is formed; a secondpiston rodwhoseupper end is detachablycoupled with the first central throughhole of the first piston, whose outer circumference is slidably penetratingly coupled with theupperendofthethirdguidevessel, andontheupper-center of which a second recess communicating with the first lower chamber is formed and on the lower-center of which a third recess communicatingwiththe secondupper chamber is formed; a second piston with which the second piston rod is detachablycoupled, atthe centercommunicatingwiththethird recess of which a second central throughhole is formed and whose outer circumference is slidably coupled along the inner circumference of the third guide vessel; a first check valve including a first valve actuator which is disposed in a space formed between the first central throughhole andthe second recess, a number of oil path grooves which are formed along the inner circumference of the first recess in order to make oil moving from the lower chamber of the first chamber to the upper chamber thereof flow by an amount of a first oil flow when the first recess is closed by the first valve actuator according to descending of the first piston, and a small-sized throughhole which is formed in the first valve actuator, and makes oil moving from the upper chamber ofthe first chamber to the lower chamberthereof flow by an amount of a second oil flow which is smaller than the amount of the first oil flow when the second recess is closed by the first valve actuator according to ascending of the first piston; a second check valve including a second valve actuator which is disposed in a space formed between the second central throughhole and the lower end of the second piston rod, a number of oil path grooves which are formed along the inner circumference of the third recess in order to make oil moving from the lower chamber of the second chamber to the upper chamber thereof flow by an amount of a first oil flow when the second recess is closed by the second valve actuator according to descending of the second piston, and a small-sized throughhole which is formed in the second valve actuator, and makes oil moving from the upper chamber of the second chamber to the lower chamber thereof flow by an amount of a second oil flow which is smaller than the amount of the first oil flow when an extension hole is closed by the second valve actuator according to ascending of the second piston; a sealing cap which is detachably coupled with the lower end of the third guide vessel at a sealed state; and an elasticmember which is installed in the second lower chamber to thereby elastically support the second piston, which is compressed at the time of descending of the second piston according to opening of the door and provides a restoring force which can ascend the piston unit at the time of returning the door.