Patent Grant
8677561
The present invention relates to an automatic door closer unit, and more particularly, to an automatic door closer that is simple in configuration, thereby making it easy to perform its machining, and that has hydraulic circuits, through which oil is guided at the time when a door is open and closed, provided independently of each other, thereby ensuring good stability in operation and preventing the oil charged into the inside from leaking to the outside.
Generally, a door closer is an automatic door closing device that is installed on a large-sized steel door like a fire-proof door and is automatically returned slowly to its original position after the door is open.
Conventional automatic door closers have various structures in accordance with the kinds of door. Among them, there has been proposed Korean Patent No. 446221 issued to the same applicant as the present invention, which discloses an automatic door closer having a compact volume capable of improving the merchantability and mechanical durability thereof.
By the way, the conventional automatic door closers are configured wherein so as to control a door closing speed, a hydraulic circuit for adjusting an amount of oil and a hydraulic circuit of a check valve are operated cooperatively to each other, thereby making it difficult to perform the machining and raising the cost of the product. Moreover, the two hydraulic circuits are provided in the state of being not isolated from each other and have influences on each other, thereby decreasing the stability of the operation of the product.
Besides, in the conventional door closers, a shaft is disposed pierced through an outside housing and an adjuster is disposed on the side thereof, so that if fire occurs, the sealing is damaged by the external heat to cause the charged oil to leak to the outside and further to make the fire transferred to the back surface of a fire-proof door through the leaking oil.
Accordingly, the present invention has been made in view of the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide an automatic door closer that can have a hydraulic circuit for damping and a hydraulic circuit for controlling a door closing speed, through which oil is guided at the time when a door is open and closed, provided independently of each other, thereby ensuring the stability of the operation thereof and simply adjusting the door closing speed.
It is another object of the present invention to provide an automatic door closer that is capable of completely preventing the oil charged thereinto from leaking to the outside, thereby being appropriately applied to a fire-proof door.
It is yet another object of the present invention to provide an automatic door closer that can adopt a spiral spring having a substantially low stress variation value, thereby enabling a user to open a door, without the application of any strong force thereto, and can provide a good elastic force at the time when the door is closed, thereby gently performing the door closing operation.
It is still another object of the present invention to provide an automatic door closer that can be simple in configuration, be minimized in the number of parts, and adopt a detachable coupling structure in which easy assembling is achieved, so that the machining and assembling are excellent and the whole size is compact.
It is still yet another object of the present invention to provide an automatic door closer that can have a rotary vane and an activating shaft formed integrally to each other and modularized, thereby improving the assembility and durability thereof.
It is still another object of the present invention to provide an automatic door closer that can basically prevent the generation of metal chips caused by the friction between parts during the operation, thereby keeping hydraulic circuits from being malfunctioned by means of the metal chips.
To accomplish the above objects, according to an aspect of the present invention, there is provided an automatic door closer including: a main housing mounted on a door and having the shape of a cylinder having a closed lower portion; a damper housing disposed along the inner periphery of the upper portion of the main housing so as to divide the interior of the main housing into an upper chamber and a lower chamber, the damper housing having oil charged thereinto and a fixed vane formed at one side of the inner peripheral surface thereof in such a manner as to be projected toward the center thereof; a cover adapted to be fixedly coupled to the upper periphery of the main housing so as to maintain the sealing state with the damper housing; an activating shaft having one end extended to the outside through the cover in such a manner as to be rotatably supported and the other end rotatably supported against the bottom surface of the main housing through the damper housing, the one end extended to the outside being connected to a door frame through a link; a rotary vane formed integrally to the outer periphery of the activating shaft so as to divide the interior of the damper housing into first and second chambers, together with the fixed vane; a return spring mounted in the lower chamber in such a manner as to be compressed at the time when the door is open the door and to provide a returning force of returning the activating shaft to an initial setting position at the time when the door is closed; and damping means adapted to control the opening and closing speeds of the door and to selectively provide a damping function if the activating shaft and the rotary vane are rotated in a closing direction of the door by means of the returning force of the return spring.
According to the present invention, preferably, the damping means includes a check valve disposed at a first hydraulic circuit, formed on the rotary vane and moving to the first and second chambers, so as to open the first hydraulic circuit at the time when the door is open and to shut the first hydraulic circuit at the time when the door is closed.
According to the present invention, preferably, the automatic door closer further includes closing speed-controlling means adapted to control the closing speed of the door through the adjustment of an amount of oil moving between the first and second chambers.
According to the present invention, preferably, the closing speed-controlling means includes: a second hydraulic circuit moving to the first and second chambers from the front and rear ends of the rotary vane through the intermediate portion of the activating shaft; and a speed-adjusting bolt disposed at the second hydraulic circuit so as to control the closing speed of the door through the adjustment of an amount of oil of the second hydraulic circuit.
According to the present invention, preferably, the second hydraulic circuit includes: a first passage extended from the front end of the rotary vane to the intermediate portion of the activating shaft in such a manner as to communicate with the first chamber; a second passage parallel to the first passage at a different height from the first passage and extended from the rear end of the rotary vane to the intermediate portion of the activating shaft in such a manner as to communicate with the second chamber; and a connection passage communicating with the first passage and the second passage in a perpendicular relation with the first passage and the second passage, and wherein the speed-adjusting bolt is screw-coupled to the activating shaft in the vertical direction so as to adjust the opening degree of the connection passage.
According to the present invention, preferably, the check valve includes: the first hydraulic circuit formed on the rotary vane so as to move to the first and second chambers; and a ball valve disposed in the first hydraulic circuit so as to open the first hydraulic circuit at the time when the door is open and to shut the first hydraulic circuit at the time when the door is closed.
According to the present invention, preferably, the automatic door closer further includes closing speed-controlling means by angle adapted to reduce the damping force generated by the damping means when the activating shaft and the rotary vane are rotated in the closing direction of the door, by predetermined angle section, so as to control the closing speed of the door by angle.
According to the present invention, preferably, the closing speed-controlling means by angle includes at least one accelerating groove formed on the bottom surface of the damper housing to form at least one accelerating section in the circumferential direction, and the section where the accelerating groove is not formed is set as a delaying section delaying the closing speed of the door.
According to the present invention, preferably, the automatic door closer further includes an initial position-setting protrusion formed at one side of the fixed vane along the inner peripheral surface of the damper housing so as to set an initial position of the door; and an opening angle-restricting member disposed at the other side of the fixed vane so as to restrict the opening angle of the door.
According to the present invention, preferably, the automatic door closer further includes a first bearing disposed on the bottom surface of the main housing so as to rotatably support the lower portion of the activating shaft; and a second bearing having a top portion disposed on the cover so as to rotatably support the upper portion of the activating shaft.
According to the present invention, preferably, the return spring is disposed with an elastic force in the main housing in such a manner as to be rotated to a given angle in one direction and to provide a final closing force at the time when the door is closed.
According to the present invention, preferably, the automatic door closer further includes a rail member disposed on the top end of a door frame and having a rail groove; a link member having one end connected to the upper portion of the activating shaft; and a roller member adapted to slidingly connect the other end of the link member along the rail groove of the rail member.
According to the present invention, preferably, the automatic door closer is disposed on the door by means of a fixing bracket, and the upper portion of the activating shaft is connected to the door frame through a two-bar linkage.
According to the present invention, preferably, the automatic door closer further includes: a first hinge extended from an extended portion in such a manner as to be bent perpendicularly thereto and fixed to the side of the door, the extended portion being extended from one side of the main housing so as to form a contacted surface with the door; and a second hinge having upper and lower coupling portions being coupled to both end portions of the activating shaft extended up and down from the main housing and a connection portion adapted to connect the upper and lower coupling portion to each other, the second hinge being extended from the upper and lower coupling portions in such a manner as to be bent perpendicularly thereto and fixed to the side of the door frame.
To accomplish the above objects, according to an aspect of the present invention, there is provided an automatic door closer including: a rail member disposed on the top end of a door frame and having a rail groove; a door closer unit disposed on the top side of a door so as to provide an automatic returning force to the door at the time when the door is open; a link member having one end connected to the upper portion of an activating shaft of the door closer unit; and a roller member adapted to slidingly connect the other end of the link member along the rail groove of the rail member.
According to the present invention, the automatic door closer is capable of completely preventing the oil charged thereinto from leaking to the outside, so that when disposed on a fire-proof door, it can keep fire from occurring by means of the oil leaking to the outside.
In addition, the automatic door closer has the hydraulic circuits for the oil moving between the first and second chambers at the time when the door is open and closed in such a manner as to be formed independently of each other, through the damper housing and the activating shaft, which is unlike the conventional practice, thereby ensuring the stability of the operation thereof, improving the function of the check valve, and more precisely adjusting the door closing speed through the speed-adjusting bolt.
Further, the automatic door closer is simple in configuration, is minimized in the number of parts, and has a detachable coupling structure in which easy assembling is achieved, such that the machining and assembling are excellent and the whole size is compact.
Furthermore, the automatic door closer adopts the spiral spring having a substantially low stress variation value, thereby enabling a user to open the door, without the application of any strong force thereto, and provides a good elastic force at the time when the door is closed, thereby gently performing the door closing operation.
Hereinafter, an explanation on an automatic door closer according to the present invention will be in detail given with reference to the attached drawings.
Referring to
Referring to
The main housing 10 has a lower chamber 10a formed on the lower portion of the inside thereof, into which the spiral spring 30 is inserted, and an upper chamber 10b formed on the upper portion of the inside thereof, into which the damper housing 50 is inserted. In this case, the upper chamber 10b has a larger diameter than the lower chamber 10a, and through the difference between the diameters of the upper chamber 10b and the lower chamber 10a, a stage protrusion 10c is formed along the boundary between the upper chamber 10b and the lower chamber 10a, along which the underside end of the damper housing 50 is seated.
The lower chamber 10a has a pair of spring-fixing grooves 11a and 11b formed symmetrically on both sides of the inner peripheral surface thereof. The formation of the pair of spring-fixing grooves 11a and 11b enables a right type spiral spring or a left type spiral spring to be selectively used in accordance with the opening directions of a door D. Also, oil is supplied to the lower chamber 10a so as to maintain the lubrication and durability of the spiral spring 30 and to absorb the noise generated upon the operation of the spiral spring 30.
The spiral spring 30 serves as a return spring which is compressed at the time when the door D is open and supplies a returning force to permit the activating shaft 70 to be returned to an initial setting position at the time when the door D is closed. According to the present invention, the spiral spring 30 is used as the return spring, but it may be used as a variety of springs like a torsion spring, and so on, only if the activating shaft 70 is returned to the initial setting position.
The upper chamber 10b has a plurality of damper housing-fixing grooves 13 formed along the inner peripheral surface thereof in the circumferential direction and a screw portion 14 formed along the upper side of the inner peripheral surface thereof, to which the outer periphery of the cover 90 is screw-coupled.
The main housing 10 has a bearing insertion groove 15a formed on the bottom surface thereof so as to insert a lower bearing B1 thereinto, and the bearing-inserting groove 15a has a shaft-supporting groove 15b formed stepped on the center thereof so as to seat the lower end of the activating shaft 70 thereon.
The main housing 10 has a rear side coupled to a fixing bracket 20, and through the fixing bracket 20, the main housing 10 is fixedly mounted on the door D. In case where the door closer 1 is mounted on the door D, first, the fixing bracket 20 is fixed to a door wall by means of fixing screws, and then, the main housing 10 is coupled to the fixing bracket 20 and fastened thereto by means of fixing screws.
Referring to
On the other hand, the spiral spring 30 has a relatively lower elastic coefficient than the torsion spring or compression spring used in the conventional door closer, so that the door D can be open without the application of lots of force thereto.
Referring to
Further, the damper housing 50 has a fixed vane 54 formed as an integral body thereto at one side of the inner peripheral surface thereof in such a manner as to be projected toward the center thereof. The fixed vane 54 has a first packing 54a coupled to the front end thereof, and the first packing 54a is brought into close contact with the intermediate portion 70b of the activating shaft 70. The fixed vane 54 and a rotary vane 74 as will be discussed later serve to divide the interior of the damper housing 50 into first and second chambers C1 and C2.
Moreover, the damper housing 50 has an initial position-setting protrusion 55 formed at one side of the fixed vane 54 along the inner peripheral surface thereof so as to set an initial position of the door D and an opening angle-restricting member 56 disposed at the other side of the fixed vane 54 so as to restrict the opening angle of the door D. The opening angle-restricting member 56 has one side 56a fixed by means of a fixing protrusion 52 formed near the fixed vane 54 and the other side 56b formed bent to restrict the rotation of the rotary vane 74. In this case, the angle between a front end 55a of the protrusion 55 for setting the initial position of the door D and the other side 56b of the opening angle-restricting member 56 corresponds to a desired opening angle of the door D.
Further, the damper housing 50 has a plurality of coupling protrusions 57 formed along the outer peripheral surface thereof in such a manner as to be insertedly coupled to the plurality of damper housing-fixing grooves 13. The coupling of the plurality of coupling protrusions 57 to the damper housing-fixing grooves 13 prevents the damper housing 50 from being rotated together with the activating shaft 70 within the upper chamber 10b during the rotation of the activating shaft 70.
Referring to
Referring to
Among the above sections, the third delaying section D3 is a section finally delaying the closing speed of the door D so as to protect a user's hand if the user's hand is caught between the door D and the door frame F, and the third accelerating section S3 is a section accelerating the closing speed of the door D so as to permit a latch (not shown) of the door D to be locked to a locking groove (not shown) formed on the door frame F.
Moreover, the first to third accelerating grooves 58a to 58c have different lengths and widths from each other in accordance with the kinds of door, thereby making possible to appropriately adjust the closing speed of the door.
The accelerating and delaying sections will be in detail explained when the operation of the automatic door closer according to the present invention will be described.
Additionally, the damper housing 50 has a second seating groove 59 formed along the inner peripheral surface of the top end thereof so as to seat the underside end of the cover 90 thereon.
Referring to
Further, the activating shaft 70 has a speed-adjusting bolt 73 detachably inserted from the front end of an upper portion 70a into the connection passage 71c along the axial direction thereof. In this case, the speed-adjusting bolt 73 is sealed by means of a plurality of O-rings O1 inside the activating shaft 70 so as to prevent oil from leaking to the outside.
If the speed-adjusting bolt 73 is rotated by a given angle in a clockwise or counterclockwise direction, a front end 73c of the speed-adjusting bolt 73 adjusts the opening degree of the connection passage 71c to control the amount of oil passed through the connection passage 71c, thereby adjusting the closing speed of the door D. In this case, the speed-adjusting bolt 73 has a head portion 73a having an adjusting groove 73b formed to insert the front end of a driver thereinto, so that a tool like a driver can be used by a user to easily rotate the speed-adjusting bolt 73. The second hydraulic circuit and the speed-adjusting bolt 73 constitute door closing speed-controlling means.
Furthermore, the activating shaft 70 has the rotary vane 74 formed on one surface of the intermediate portion 70b in such a manner as to be protruded to a position near the inner peripheral surface of the damper housing 50. The rotary vane 74 has a second packing 74a coupled to the front end thereof, and the second packing 74a is brought into close contact with the inner peripheral surface of the damper housing 50. Further, the rotary vane 74 has a check valve 77 adapted to move the oil within the first and second chambers C1 and C2 only in one direction during the rotation together with the activating shaft 70. The check valve 77 permits the oil within the second chamber C2 to move to the first chamber C1 at the time when the door D is open, and contrarily, restricts the movement of the oil within the first chamber C1 to the second chamber C2. At the time when the door D is closed, accordingly, the oil in the first chamber C1 is passed sequentially through the first passage 71a, the connection passage 71c and the second passage 71b and is then moved to the second chamber C2.
The check valve 77 includes an oil-passing hole 75 passed through the rotary vane 74 and a ball valve 77a disposed movably in the oil-passing hole 75 so as to open and close the oil-passing hole 75. In this case, the oil-passing hole 75 has a first inlet 75a communicating with the first chamber C1, which is formed larger than a second inlet 75b communicating with the second chamber C2, and a pin 78 is disposed on the first inlet 75a side so as to prevent the ball valve 77a from escaping from the oil-passing hole 75. In this case, the oil-passing hole 75 formed to pass through the rotary vane 74 forms a first hydraulic circuit.
According to the present invention, the check valve 77 is adopted by using the ball valve 77a, but it is possible to adopt a check valve structure having various known shapes like a plate valve.
Further, when the activating shaft 70 is inserted into the through-hole 51 of the damper housing 50, it is sealed by means of O-rings O2, thereby preventing the oil in the damper housing 50 from leaking to the main housing 10.
Furthermore, the activating shaft 70 has the fixing slot 79 formed at the lower portion 70c in such a manner as to fixedly insert the other end 53 of the spiral spring 30 thereinto.
If the activating shaft 70 and the damper housing 50 are coupled to each other, the sealing between the first chamber C1 and the second chamber C2 is achieved by means of the first packing 54a and the second packing 74a, and also, the sealing between the activating shaft 70 and the damper housing 50 is achieved by means of the O-rings O2, thereby making it possible to perform the sealing in a simple manner.
Referring to
Also, the cover 90 has a through-hole 91 formed on the center thereof, through which the upper portion 70a of the activating shaft 70 is passed, and a bearing insertion groove formed around the through-hole 91 so as to insert a bearing B2 thereinto and to rotatably support the activating shaft 70 thereagainst.
Further, the cover 90 has a deviation-preventing protrusion 93 formed along the inner periphery of the through-hole 91 so as to prevent the deviation of the activating shaft 70.
The door closer 1 having the above-mentioned configuration according to the present invention is assembled through the following procedure.
First, the bearing B1 is pressed and fitted to the bearing insertion groove 15a of the main housing 10, and then, the spiral spring 30 is inserted into the lower chamber 10a. In this case, one end 31 of the spiral spring 30 is fixed to the spring-fixing groove 11a of the main housing 10.
Next, the O-rings O2 and O5 are mounted along the outer periphery of the activating shaft 70, and the second packing 74a is mounted on the rotary vane 74 of the activating shaft 70. Moreover, the first packing 54a is mounted on the fixed vane 54 of the damper housing 50.
In this state, the activating shaft 70 is insertedly coupled to the through-hole 51 of the damper housing 50 and is then modularized. At this time, the rotary vane 74 of the activating shaft 70 is located at an initial setting position indicated on a given position on the damper housing 50.
After that, the coupled body between the activating shaft 70 and the damper housing 50 is first inserted into the upper chamber 10b of the main housing 10. In this case, the other end 33 of the spiral spring 30 is inserted into the fixing slit 79 of the activating shaft 70, thereby connecting the activating shaft 70 and the spiral spring 30 to each other.
In this state, the coupled body between the activating shaft 70 and the damper housing 50 is rotated by about 180° to 200° and it is then pressed and fitted to the main housing 10 at a point where the center of the fixed vane 54 of the damper housing 50 and the center of the main housing 10 correspond to each other, thereby inserting the lower portion 70c of the activating shaft 70 into the bearing B1. Accordingly, the door closer according to the present invention has a last closing force of the door D, that is, a force of inserting the latch of the door D into the locking groove of the door frame F.
After that, oil with high viscosity and incompressibility is charged into the first and second chambers C1 and C2 of the damper housing 50. The oil charging may be performed in a vacuum state after the cover 90 has been assembled.
After that, the O-rings O3 and O4 are mounted along the outer periphery of the cover 90, and the bearing B2 is inserted into the bearing insertion groove 92. Next, the cover 90 is screw-coupled to the main housing 10. At this time, if the cover 90 is completely coupled to the main housing 10, the underside surface of the cover 90 is brought into close contact with the interior of the upper portion of the damper housing 50, thereby achieving the sealing in the interior of the damper housing 50.
After that, residual oil is removed, and the speed-adjusting bolt 73 is assembled to the upper end of the activating shaft 70, thereby completing the assembly of the door closer according to the present invention.
Now, an explanation on the operation of the door closer according to the present invention will be given with reference to
The closed state of the door D, that is, the initial state of the door D is when one surface of the rotary vane 74 comes into close contact with the front end 55a of the initial position setting protrusion 55.
If the door D is open in the initial state, as shown in
If the door D is more open, as shown in
If the door D is completely opened, the rotary vane 74 is brought into close contact with the other side 56b of the opening angle-restricting member 56. In this state, if the door D is released from the user passing the door D, the external force applied to the door D is removed and the door D is returned to its original position by means of the elastic force of the spiral spring 30.
At this time, the rotary vane 74 is rotated in the counterclockwise direction, and the oil in the first chamber C1 is introduced into the first inlet 75a of the oil-passing hole 75. Through the oil pressure, the ball valve 77a closes the second inlet 75b of the oil-passing hole 75. Accordingly, the oil in the first chamber C1 is passed sequentially through the first passage 71a, the connection passage 71c and the second passage 71b pierced through the interior of the intermediate portion 70b of the activating shaft 70 and is then moved to the second chamber C2, thereby closing the door D at an appropriate speed, while preventing the sudden closing of the door D.
As shown in
The door D has a closing force of inserting the latch of the door D into the locking groove of the door frame F through the final accelerating section S3, and in this case, as shown in
On the other hand, the door closer 1 according to the present invention can be used as a sliding arm type door closer, as shown in
Referring to
The roller member 120 includes a first member 121 slidingly moving along a rail groove 111 of the rail member 110, a second member 123 hinge-connected to the other end of the link member 130, and a connection screw 125 adapted to fasten the first member 121 and the second member 123 to each other.
According to the sliding arm type door closer, at the time when the door D is open and closed, the link member 130 is turned and at the same time slides in the state of being connected to the rail member 110.
Referring to
The first link rod 210 serves as a driven link, and the second link rod 230 a drive link.
The first link rod 210 and the second link rod 230 are folded to each other in the state where the door D is closed and are unfolded from each other in the state where the door D is open.
A reference symbol H in
In the above-mentioned preferred embodiments of the present invention, the automatic door closer is disposed at the upper side of the door and is connected to the upper door frame through the sliding arm type and link arm type link devices, but a bracket structure for mounting the automatic door closer can be changed to a butterfly hinge structure, as shown in
That is, the door closer is mounted on the side of the door D through bufferfly type first and second hinges 310 and 320. In this case, the door closer 100 has a cylindrical main housing 100a in such a manner as to outwardly protrude the upper portion 70a and the lower portion 70d of the activating shaft 70 from the upper and lower portions thereof.
Also, the door closer 100 has an extended portion 101 extended from one side of the main housing 100a so as to form a relatively large contacted surface with the door D and to serve as a reinforcing plate. The first hinge 310 is extended from the extended portion 101 in such a manner as to be bent perpendicularly thereto and fixed to the side of the door D. In this case, the first hinge 310 has a plurality of screw holes 311 formed thereon in such a manner as to be fixed to the door D by means of a plurality of fixing screws.
On the other hand, the second hinge 320, which is provided to correspond to the first hinge 310, has upper and lower coupling portions 324 and 325 coupled to the upper portion 70a and the lower portion 70d of the activating shaft 70 extended from the upper and lower portions of the main housing 100a in such a manner as to suppress the rotation of the activating shaft 70, and a connection portion 323 adapted to connect the upper and lower coupling portions 324 and 325 with each other. Further, the upper and lower coupling portions 324 and 325 have the respective flat contacted surface formed on one side thereof in such a manner as to be contacted with the door frame F, which is similar to the first hinge 310, and upper and lower hinges 321 and 322 extended from one side of the contacted surface in such a manner as to be bent perpendicularly thereto and fixed to the side of the door frame F. In this case, the upper and lower hinges 321 and 322 have a plurality of screw holes 326 formed thereon in such a manner as to be fixed to the door frame F by means of a plurality of fixing screws, and the connection portion 323 has a plurality of screw holes 327 formed thereon in such a manner as to be fixed to the door frame F.
According to the present invention, as shown in
That is, one side end portion of the door D is coupled between the first hinge 310 and the extended portion 101, and one side end portion of the door frame F is coupled between the upper and lower hinges 321 and 322 of the second hinge 320 and between the upper and lower coupling portions 324 and 325.
As a result, the first hinge 310 has the extended portion 101, serving as a reinforcing plate, formed perpendicularly thereto in such a manner as to be extended from the main housing 100a, and the second hinge 320 has the upper and lower hinges 321 and 322 formed perpendicularly to the upper and lower coupling portions 324 and 325, so that even if a strong external force like strong wind is applied to the door D, it is distributed to provide high durability to the door closer 100.
According to the present invention, the automatic door closer can basically prevent the oil during working from flowing to the outside, which removes the causes of the firing by the oil leaking to the outside upon the installation on a fire-proof door.
Unlike the conventional practices, further, the automatic door closer according to the present invention can have the independently formed hydraulic circuits for the oil moving between the first and second chambers at the time when the door is open and closed, through the damper housing and the activating shaft, thereby improving the stability of the operation and the functions of the check valve, and the automatic door closer according to the present invention can vary the closing speed of the door more precisely through the speed-adjusting bolt.
Moreover, the automatic door closer according to the present invention can be simple in configuration and easy in machining and assembling, while reducing the whole size thereof to a compact size.
Additionally, the automatic door closer according to the present invention can adopt the spiral spring having a substantially low stress variation value, thereby enabling a user to open the door, without the application of any strong force thereto, and can provide a good elastic force at the time when the door is closed, thereby gently performing the door closing operation.
While the present invention has been described with reference to the particular illustrative embodiments, it is not to be restricted by the embodiments but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.
[Industrial Applicability]
The automatic door closer according to the present invention performs the direct control of the rotary motion of the door, which is usefully applied to doors for building materials, especially, fire-proof doors.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2009-0079324 | Aug 2009 | KR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/KR2010/005684 | 8/25/2010 | WO | 00 | 2/24/2012 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2011/025251 | 3/3/2011 | WO | A |
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| 51-122927 | Oct 1976 | JP |
| 20-0190952 | May 2000 | KR |
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| Entry |
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| International Search Report—PCT/KR2010/005684 dated Apr. 26, 2011. |
| Number | Date | Country | |
|---|---|---|---|
| 20120144623 A1 | Jun 2012 | US |
