Description

GUIDE RAIL WITH LOCKING DEVICE, PROTECTING DEVICE FOR PUSHING OF SCREEN DOOR, AND SCREEN DOOR DEVICE THEREWITH

Technical Field

[1] The present invention relates to a push-resistant device, a guide rail forming a sill as a lower support device, and a door apparatus including the guide rail and a door having the push-resistant device, in which the push-resistant device prevents the door from being released out of the guide rail when a perpendicular force to close/open directions of the door is exerted on the door, and the guide rail includes a locking device for locking the push-resistant device. Background Art

[2] Doors, which are closed or opened along a sill on a lower portion thereof, are provided to various places including subway platforms, elevator cages, and elevator landing floors.

[3] In the case of the subway platforms, such a door is provided as a screen door to be selectively opened/closed and separate the platform in a subway station from a track. The door is allowed to be opened only when a train is completely stopped, to prevent accidental falls to the track.

[4] In the case of the elevator cages, when the cage arrives at a landing floor of a predetermined floor, such a door is opened to an entrance to allow passengers to get on or off the cage. When the cage moves through a hoistway, the door is closed to prevent accidental falls to the hoistway. Also, such a door for opening/closing the hoistway is provided to an entrance of the landing floor. The door is opened/closed, interlocking with the cage as disclosed in Korean Utility Model Registration No. 20-0266320.

[5] FIG. 1 is a cross-sectional view illustrating a cage door and a landing floor door of a related art elevator door.

[6] A guide rail 2, forming a sill for opening/closing a landing floor door 3, is provided to an entrance of a landing floor. A groove 1 is disposed in the guide rail 2 in a longitudinal direction thereof. An upper rail 4 is disposed above an inner wall of the entrance. Hanger rollers 5 and 6 moving along the upper rail 4 are disposed above the landing floor door 3.

[7] A guide shoe 7 is disposed below the door 3. The guide shoe 7 is inserted into the groove of the guide rail 2, to prevent the door 3 from being released out of the sill when a perpendicular force is exerted on the door 3.

[8] A guide rail 8 including a groove 9 is disposed in front of a bottom of an elevator cage 18, and a door 11 is opened and closed along the guide rail 8. A guide shoe 10

moved along the groove 9 is disposed below the door 11. The guide shoe 10 moves in the state of being inserted in the groove 9 so as to prevent the door 11 from being pushed out of the guide rail 8 in a perpendicular direction.

[9] A gripper 12 is provided to the cage door 11, and an interlock roller 13 is provided to the landing floor door 3. When the cage 18 arrives at a predetermined floor, the gripper 12 is interlocked with the interlock roller 13, so that the cage door 11 and the landing floor door 3 are simultaneously opened or closed.

[10] The guide shoe 7, having a metal plate, includes an upper end, a lower end, a bracket

15, and a packet 16. The upper end is coupled to an inner side of a lower end of the landing floor door 3 (toward the cage door 11) through welding or bolting. The lower end is disposed toward a bottom 14 of the groove 1. The bracket 15 has a bent portion is disposed between the upper end and the lower end. The packet 16 is formed of a synthetic resin and surrounds a lower end and an outer circumference of the bracket 15. The guide shoe 10 includes a metal plate having the same shape as that of the guide shoe 7. An upper end of the guide shoe 10 is coupled to an outer side of a lower end of the cage door 11 (toward the landing floor door 3) through welding or bolting. A packet 19 of the guide shoe 10 is disposed toward a bottom 17 of the groove 9.

[11] The guide shoes 7 and 10 disposed below the related art doors 3 and 11 guide the doors 3 and 11 along the grooves of the guide rails 2 and 8 and serves as a push- resistant device preventing the doors 3 and 11 from being released out of the guide rails 2 and 8 when exerting a perpendicular force to the close/open directions of the doors 3 and 11. Disclosure of Invention

Technical Problem

[12] However, when the packets 16 and 19 are not sufficiently inserted into the grooves 1 and 9, and when an excessive perpendicular force is exerted on the doors 3 and 11, and when the packets 16 and 19 are damaged by fire, and when the doors are bent by heat, the guide shoes 7 and 10 are released from the guide rails 2 and 8 to open the entrance of the landing floor or the cage.

[13] To solve the above-described limitations, a related art guide shoe has been disclosed as illustrated in FIG. 2.

[14] FIG. 2 is a front view illustrating a guide shoe according to a related art.

[15] A guide shoe 20 includes a strap-shaped bracket 21 having a predetermined width and packets 22 and 23 disposed in lower portions of the bracket 21. The guide shoe 20 is disposed on a lower end of a door. The bracket 21 is inserted into a groove of a guide rail to a predetermined depth to prevent the guide shoe 20 from being pushed out of the groove of the guide rail when a perpendicular force is exerted on the door.

[16] However, although the guide shoe 20 serves as a push-resistant device, when foreign objects are introduced into the groove of the guide rail, a frictional force is greatly increased between the guide shoe 20 and the guide rail, and the load of a motor driving the door is also increased. Thus, the motor is damaged and is not working. Also, the bracket 21 includes a wide metal plate to increase material costs. Technical Solution

[17] The present invention has been made in an effort to solve the above-described limitations of the related art. An object of the present invention is to provide a simple and economical push-resistant device of a door.

[18] Another object of the present invention is to provide a push-resistant device having a low breakdown rate and achieving simple manufacturing and constructing.

[19] Further another object of the present invention is to provide a door including a push- resistant device, a guide rail including a locking device coupled to the push-resistant device, and a door apparatus.

Advantageous Effects

[20] According to the present invention, when people exert perpendicular forces on doors including a screen door provided for passenger safety in a subway station, a door of an elevator cage entrance, and a landing floor door of an elevator, the doors are prevented from being pushed away, thereby preventing an accident.

[21] A landing floor door of an elevator prevents accidental falls from an entrance of a landing floor and serves as a fire barrier door preventing fire from rapidly spreading from a floor to another floor through a hoistway for an elevator cage. When fire occurs, the landing floor door is bent by heat, and a packet of a guide shoe formed of a synthetic resin is damaged. Thus, the door is released from a sill and does not serve as a fire barrier door. However, according to the present invention, since a push-resistant device disposed on a lower portion of a door is secured to a locking device of a guide rail, the door is prevented from being bent to effectively serve as a fire barrier door. Brief Description of the Drawings

[22] FIG. 1 is a cross-sectional view illustrating a cage door and a landing floor door of a related art elevator door.

[23] FIG. 2 is a front view illustrating a guide shoe according to a related art.

[24] FIG. 3 is a perspective view illustrating a push-resistant device according to an embodiment of the present invention.

[25] FIG. 4 is a perspective view illustrating a guide rail including a locking device coupled to the push-resistant device of FIG. 3. FIG. 5 is a cross-sectional view taken along a line A-A' of FIG. 4.

[26] FIG. 6 is a front view illustrating a push-resistant device according to an embodiment

of the present invention. [27] FIG. 7 is a front view illustrating the push-resistant device of FIG. 6 without a packet. [28] FIG. 8 is a schematic view illustrating the operation of a door with the push-resistant device of FIG. 3. [29] FIG. 9 is a perspective view illustrating a locking device coupled to a guide rail according to an embodiment of the present invention. [30] FIG. 10 is an exploded perspective view illustrating a locking device coupled to a guide rail according to an embodiment of the present invention. [31] FIG. 11 is a front view illustrating a push-resistant device according to another embodiment of the present invention. [32] FIG. 12 is a perspective view illustrating the push-resistant device of FIG. 11 coupled to a door. [33] FIG. 13 is a perspective view illustrating a locking device according to an embodiment of the present invention. [34] FIG. 14 is a perspective view illustrating a locking device according to another embodiment of the present invention.

[35] FIG. 15 is a cross-sectional view taken along a line A-A' of FIG. 14.

[36] FIG. 16 is a cross-sectional view taken along a line B-B' of FIG. 1.

[37] FIG. 17 is a perspective view illustrating a locking mechanism for a push-resistant device in the state where the locking device of FIG. 14 is coupled to a guide rail.

Best Mode for Carrying Out the Invention [38] To achieve the objects of the present invention, there is provided a guide rail forming a sill for a door including a push-resistant device having: a vertical portion disposed on a lower portion of the door; and a push-resistant member protruding in a closing direction of the door from the vertical portion, the guide rail including: a locking device disposed in a groove disposed in a longitudinal direction of the guide rail, the locking device limiting a vertical movement of the push-resistant member when the door is closed and the push-resistant member is inserted. [39] The locking device includes a fixing member disposed between sidewalls defining the groove, and the push-resistant member is inserted between the fixing member and a bottom of the groove when the door is closed.

[40] The fixing member may include any one of a bolt, a pin, and a plate.

[41] An entrance may be opened and closed by two doors, and two fixing members may be symmetrically disposed about a center in the longitudinal direction of the guide rail. [42] The locking device may include: a transverse member passing through sidewalls defining the groove; a moving part disposed in the groove and including a slot having a

vertical long axis, the transverse member passing through the slot such that the moving part is vertically movable; and a fixing plate disposed on a top of the moving part in a longitudinal direction of the groove, wherein when the door is closed, the push- resistant member is inserted and locked into a space defined by the fixing plate and the sidewalls of the groove.

[43] The guide rail may further include a housing including: an install member disposed on a bottom of the groove: and an insertion casing vertically disposed on the bottom through the install member and including both sides having through holes through which the transverse member passes, the moving part being inserted into the insertion casing.

[44] The moving part may have a tetragonal cylinder shape.

[45] The fixing plate may be disposed on both sides of the moving part in the longitudinal direction of the groove.

[46] The locking device may include: a housing including a through hole and a receiving portion defining an inner space, the through hole passing through an outer surface of the housing and having a smaller area than the receiving portion and communicating with the inner space; and an operating member including: a moving part including a portion passing through the through hole of the housing and inserted into the receiving portion and the other portion protruding out of the housing; a flange disposed on an end of the moving part inserted into the receiving portion, the flange caught by the through hole to be movable within the receiving portion; and a fixing plate disposed on an end of the moving part protruding from the outer surface of the housing in a longitudinal direction of the groove such that the push-resistant member is inserted below the fixing plate.

[47] The housing may include a side surface including a through hole and be coupled to the guide rail through a bolt crossing the groove.

[48] The housing may have an external form including both semi-circular side surfaces and a connecting surface connecting the side surfaces.

[49] The flange may include a planar part and be coupled to the end of the moving part through a screw.

[50] A stop flange may be disposed in a connecting portion between the receiving portion and the through hole.

[51] The through hole and the moving part may have tetragonal shapes.

[52] According to another aspect of the present invention, there is provided a push- resistant device of a door opened and closed along a guide rail of a sill, the push- resistant device including: a planar coupling portion disposed on a lower end of the door; a vertical portion extending downward from the coupling portion; and a plate hook protruding in a closing direction of the door from the vertical portion.

[53] According to another aspect of the present invention, there is provided a push- resistant device of a door opened and closed along a guide rail of a sill, the push- resistant device including: a planar coupling portion disposed on a lower end of the door; a vertical portion extending downward from the coupling portion; a packet- coupling portion extending downward from the coupling portion; a packet formed of a synthetic resin to surround an outer circumference of the packet-coupling portion; and a plate hook protruding in a closing direction of the door from the vertical portion.

[54] The push-resistant device may further include a horizontal portion bent from a lower portion of the coupling portion to an upper portion of the vertical portion.

[55] The plate hook may include a front end with a top that is inclined, tapered, or curved downward to the front end.

[56] The plate hook may include an outer circumference on which a synthetic resin is applied.

[57] The plate hook may include an upper end provided to be below the lower end of the door.

[58] According to another aspect of the present invention, there is provided a door apparatus including a door opening and closing an entrance and a guide rail forming a sill guiding the door, the door apparatus including: a plate hook protruding in a closing direction of the door from a lower portion of the door; and a locking device disposed in a groove disposed in a longitudinal direction of the guide rail such that the plate hook is inserted into the locking device when the door is closed, and the plate hook is prevented from being moved after the plate hook is inserted.

[59] The plate hook may be branched from a guide shoe moving along the groove.

[60] The locking device may include: a moving part raised while the plate hook is inserted; and a fixing plate disposed on both sides of a top of the moving part in the longitudinal direction of the guide rail, wherein the plate hook is inserted into a space defined by the fixing plate and both sidewalls of the groove.

[61] According to another aspect of the present invention, there is provided a door apparatus including a door opening and closing an entrance and a guide rail forming a sill guiding the door, the door apparatus including: a push-resistant device disposed in the guide rail and including a plate hook protruding in an opening direction of the door; and a locking device disposed in a lower portion of the door to allow the plate hook to be inserted into the locking device when the door is closed and to prevent the plate hook from being moved after the plate hook is inserted.

[62] Hereinafter, the present invention will now be described more fully with reference to the accompanying drawings.

[63] FIG. 3 is a perspective view illustrating a push-resistant device according to an embodiment of the present invention. FIG. 4 is a perspective view illustrating a guide

rail including a locking device coupled to the push-resistant device of FIG. 3. FIG. 5 is a cross-sectional view taken along a line A-A' of FIG. 4.

[64] A push-resistant device 30 is provided with a packet 37 and a plate hook 35 branched from a coupling portion 31. The push-resistant device 30 includes the coupling portion 31, a horizontally bent horizontal portion 32 from the coupling portion 31, a packet- coupling portion 33, a vertical portion 34, and a plate hook 36. The coupling portion 31 is provided in a vertical plane coupled through a bolt and a nut in a lower portion of a door. The packet-coupling portion 33 vertically bends downward from one end of the horizontal portion 32. The vertical portion 34 vertically bends downward from the end of the horizontal portion 32 and is parallel with the packet-coupling portion 33. The plate hook 36 extends from one side of the vertical portion 34, i.e., in a closing direction of the door. The packet 37 formed of a synthetic resin is disposed to surround an outer circumference of the packet-coupling portion 33. A top of the plate hook 36 includes a taper face 35 or a curved surface going down toward a front end. A rubber or synthetic resin layer is disposed inward on an outer surface of the entire plate hook 36 from the front end to a predetermined length of the plate hook 36 or to the entire plate hook 36.

[65] Referring to FIG. 4, a groove 1 is disposed in a guide rail 2 in a longitudinal direction of the guide rail 2, and a locking device 40 is disposed in a center in the longitudinal direction of the guide rail 2. The locking device 41 includes an operating member 41 and a housing 50 allowing the operating member 41 to vertically move within a predetermined range. The operating member 41 includes a moving part 43 and a fixing plate 44. The moving part 43 includes a slot 42 having a vertical length greater than a horizontal length. The fixing plate 44 is disposed on an upper end of the moving part 43 in the longitudinal direction of the guide rail 2 toward both sides thereof. The housing 50 includes an insertion casing 45 and supporting elements 46 and 47. The moving part 43 is inserted into the insertion casing 45, or the insertion casing 45 is inserted into the moving part 43. The supporting elements 46 and 47 are disposed toward both sides in a lower portion of the insertion casing 45 and coupled to a bottom of the groove 1 using a screw.

[66] A bolt hole 57 is disposed in an outer surface from the center in the longitudinal direction of the guide rail 2. Bolt holes 53 and 54 laterally aligned with the bolt hole 57 are disposed in both side surfaces 51 and 52 defining the groove 1. Also, the insertion casing 45 includes bolt holes 55 and 56 that are laterally aligned with the bolt holes 53, 54, and 55 and the slot 42 when the housing 50 is disposed in the groove 1. The bolt holes 54, 55, 56, and 57 and the slot 42 have no tread, but the bolt hole 53 has a tread engaging with a tread disposed in an end of a bolt 58.

[67] The housing 50 is disposed to bringthe insertion casing 45 in a center in a Ion-

gitudinal direction of the groove 1. The bolt 58 is inserted into the bolt holes 57, then 54, then 56, then 42, then 55, and finally screwed into the bolt hole 53, with the moving part 43 of the operating member 41 inserted in the insertion casing 45, so that the operating member 41 is vertically movable with respect to the guide rail 2. At this point, since the slot 42 of the moving part 43 has the great vertical length with respect to the bolt 58, the operating member 41 is vertically movable, but a moving distance is limited by the slot 42.

[68] The insertion cashing 45 is a hollow tetragonal cylinder having a predetermined thickness, but the moving part 43 is a solid tetragonal cylinder. Also, both sides of the fixing plate 44 bend downward to prevent an external foreign object from being introduced into the insertion casing 45.

[69] The operating member 41 and the housing 50 are provided to both a guide rail forming a sill of the cage door to open/close an entrance of an elevator cage and the guide rail 2 forming a sill of the floor door to open/close an entrance of a landing floor.

[70] The locking device 40 is disposed in the center in the longitudinal direction of the groove 1 of the guide rail 2. When the door is provided in duplicate, and the two doors in a opening state move toward the center to be in a closing state, the plate hooks 36 of the push-resistant devices 30 protruding to face each other on the doors bring the taper faces 35 of the front ends to be in contact with a bottom of the fixing plate 44 of the locking device. At this point, as the doors are closer to each other, the taper faces 35 raise the fixing plate 44 higher. Here, the vertical length of the slot 42 disposed in the moving part 43 is larger than a diameter of the bolt 58, to allow a vertical movement of the moving part 43, and when the taper face 35 of the plate hook 36 is inserted into the fixing plate 44, the taper face 35 comes in contact with the fixing plate 44 to raise the moving part 52. As such, when the doors are closed, a raised height of the fixing plate 44 is limited by the vertical length of the slot 42. The plate hook 36 is inserted and fitted into the fixing plate 44 and the side surfaces 51 and 52 of the groove 1, so that the push-resistant device 30 is locked to the locking device 40.

[71] When the doors move in an opposite direction to be opened, the plate hook 36 is released from the fixing plate 44 and the operating member 41 goes down.

[72] The install height of a door and a guide rail is various depending on manufacturers and constructors. Thus, when the operating member 41 is fixed at a predetermined height, the plate hook 36 may be not inserted into the fixing plate 44, or stopped in an insertion operation. The operating member 41 is allowed to vertically move, and the taper face 35 is provided in an end of the plate hook 36, so that even when a guide rail and a door are constructed at various heights, the push-resistant device 30 with a predetermined standard can be provided.

[73] Although the guide rail 2 is described under a condition where the entrance is opened

or closed by the two doors, a modification to the guide rail 2 can be made to be applied under a condition that an entrance is opened by a single door.

[74] Under the condition that an entrance is opened by a single door, the locking device

40 is disposed in an end of the guide rail 2 and the fixing plate 44 of the moving part 43 is disposed on only one side of a top of the moving part 43.

[75] The synthetic resin layer, disposed on the outer surface of the plate hook 36, reduces noise generated when the plate hook 36 comes in contact with the fixing plate 44.

[76] FIG. 6 is a front view illustrating a push-resistant device according to an embodiment of the present invention. FIG. 7 is a front view illustrating the push-resistant device of FIG. 6 without a packet.

[77] While the push-resistant device 30 of FIG. 3 includes the bent horizontal portion 32 between the coupling portion 31 and both the packet-coupling portion 33 and the vertical portion 34, a push-resistant device 60 does not include the horizontal portion 32. Also, a packet-coupling portion 62, a vertical portion 63, and a plate hook 64 are disposed in a single plane in a lower portion of a coupling portion 61. A packet 65 is disposed on the packet-coupling portion 62. Referring to FIGs. 6 and 7, the push- resistant device 60 having a metal in a single plane is applied in the case where the groove 1 of the guide rail 2 is disposed vertically below the coupling portion 61. In the case of the push-resistant device 30 of FIG. 3, when the groove 1 of the guide rail 2 is spaced a predetermined distance from a region disposed vertically below the coupling portion 61, the width of the horizontal portion 32 is provided to correspond to the distance from the region, so that a packet is inserted into a groove.

[78] FIG. 8 is a schematic view the operation of a door with the push-resistant device of

FIG. 3.

[79] Referring to FIG. 8, doors 81 and 82 are used to open/close a landing floor entrance, which illustrates a closing state. A guide rail 2 is disposed vertically below the doors 81 and 82. The locking device 40 of FIGs. 4 and 5 is disposed in a center in a longitudinal direction of a groove 1 of the guide rail 2. A typical guide shoe 83 and the push-resistant device 30 of FIG. 3 are disposed in a lower end of the door 81 with the plate hook 36 disposed in a closing direction of the door 81. The push-resistant device 30 is disposed at a predetermined height to allow the plate hook 36 moving in the closing direction of the door 81 to be inserted below the fixing plate 44 of the locking device 40.

[80] A typical guide shoe 83' and a push-resistant device 30' are disposed in a lower end of the door 82. The push-resistant device 30' is disposed at a predetermined position to allow a plate hook 36' to be inserted below the fixing plate 44 when the door 82 is closed.

[81] As such, when the entrance is closed by the doors 81 and 82, upper portions of the

plate hooks 36 and 36' are inserted and locked to a space defined by the fixing plate 44 and both sidewalls of the groove. Thus, even when a perpendicular force is exerted on the doors 81 and 82, the plate hooks 36 and 36' are not released from the locking device 40. Although FIG. 8 relates to a door for closing/opening a landing floor entrance, the structure illustrated in FIG. 8 may be applied to a door for closing/ opening an entrance of an elevator cage in the same manner.

[82] FIG. 9 is a perspective view illustrating a locking device coupled to a guide rail according to an embodiment of the present invention.

[83] A locking device 100 illustrated in FIG. 9 is disposed in a center in a longitudinal direction of the groove 1 of the guide rail 2 disposed below the door. The locking device 100 includes a bottom 101, side surfaces 102 and 103, and two links 104 and 105. The bottom 101 is coupled to a bottom of the groove using a screw. The both side surfaces 102 and 103 vertically bend from the bottom 101. The two links 104 and 105 are disposed on portions of the both side surfaces.

[84] When the locking device 100 is disposed in the center of the groove 1 of the guide rail 2 of FIG. 8, the plate hook 36 of the push-resistant device 30 and the plate hook 91 of the push-resistant device 30' are respectively inserted on both sides of the locking device 100, and the plate hooks 36 and 36' are respectively inserted and locked into the links 104 and 105.

[85] FIG. 10 is an exploded perspective view illustrating a locking device coupled to a guide rail according to an embodiment of the present invention.

[86] Referring to FIG. 10, a locking device 110 includes a fixing plate 111, four guide plates 114, 115, 116, and 117, and a moving part 118. The fixing plate 111 has a predetermined width to be inserted into a groove 1 of a guide rail 2. The four guide plates 114, 115, 116, and 117 bend downward from both side surfaces of the fixing plate 111. The moving part 118 protrudes downward in a center of a bottom of the fixing plate 111 and includes a slot 119 having a vertical long axis. The locking device 110 is vertically movable with respect to the guide rail 2 because a bolt 112 crossing the groove 1 passes through the slot 119. When a door is closed and the plate hooks 36 and 36' of the push-resistant devices 30 and 30' of FIG. 3 are inserted below both sides of the fixing plate 111, a raised height of the fixing plate 111 is limited by a vertical length of the slot 119. Thus, the plate hooks 36 and 36' are locked into a space defined by the fixing plate 111 and both sidewalls of the groove 1.

[87] FIG. 11 is a front view illustrating a push-resistant device according to another embodiment of the present invention. FIG. 12 is a perspective view illustrating the push-resistant device of FIG. 11 coupled to a door.

[88] Referring to FIG. 11, a push-resistant device 120 is provided without the packet- coupling portion 33 and the packet 37 from the push-resistant device 30 of FIG. 3.

[89] Except for the difference, the push-resistant device 120 is the same as the push- resistant device 30 illustrated in FIG. 3 in that a plate hook 36 protrudes in a closing direction of a door below a vertical portion 34, and the plate hook 36 is inserted into a locking device as illustrated in FIGs. 4, 9 and 10. Thus, the door is prevented from being pushed.

[90] Referring to FIG. 12, a locking device 41 is disposed in a center of a groove 1 of a guide rail 2. Typical guide shoes 83 and 84 and the push-resistant device 120 are disposed on a lower portion of a left door 81. Typical guide shoes 83' and 84' and a push-resistant device 120' are disposed on a lower portion of a right door 82. The push- resistant device 120' has the same structure as the push-resistant device 120 except for a plate hook 36' facing the plate hook 36.

[91] The push-resistant devices 120 and 120' are disposed at predetermined positions on the lower portions of the doors 81 and 82, to allow the plate hooks 36 and 36' to be inserted below a plate hook 121 when the doors are closed.

[92] FIG. 13 is a perspective view illustrating a locking device according to an embodiment of the present invention.

[93] Referring to FIG. 13, a locking device includes bolts 131 and 132 crossing a groove

1 of a guide rail 2 forming a sill of a door. Although the bolts 131 and 132 are exemplified as the locking device of FIG. 3, a plate crossing the groove 1 has the same effect.

[94] The bolts 131 and 132 are symmetrical about a center line C perpendicular to a longitudinal direction of the guide rail 2. When the door moves, the plate hook 36 of the push-resistant device 30 is inserted into a space defined by both sidewalls of the groove 1 and lower portions of the bolts 131 and 132. At this point, the top of the plate hook 36 is prevented from moving by the bolts 131 and 132, thus the plate hook 36 is in a locking state. Although the bolts 131 and 132 are exemplified as crossing members in FIG. 13, crossing members with various shapes including plate and pin shapes can have the same effect.

[95] Also, although the crossing members passing through the both sidewalls of the groove are exemplified, crossing members with various structures disposed between both sidewalls of a groove has the same effect.

[96] FIG. 14 is a perspective view illustrating a locking device according to another embodiment of the present invention. FIG. 15 is a cross-sectional view taken along a line A-A' of FIG. 14. FIG. 16 is a cross-sectional view taken along a line B-B' of FIG. 1. FIG. 17 is a perspective view illustrating a locking mechanism for a push-resistant device in the state where the locking device of FIG. 14 is coupled to a guide rail.

[97] A locking device 140 includes an operating member 141 and a housing 154. The operating member 141 is raised while a plate hook 36 of a push-resistant device 30 is

inserted. The housing 154 limits a vertically moving distance of the operating member 141 and prevents the operating member 141 from being released out of a guide rail 2.

[98] The operating member 141 includes a release-prevention plate 142 and a moving part

143. The release-prevention plate 142 is disposed in a longitudinal direction of a groove 1 of the guide rail 2. The moving part 143 protrudes downward from a center of the release-prevention plate 142. A flange 145 is coupled to a bottom of the moving part 143 through a screw 144. The moving part 143 has a tetragonal shape, and the flange 145 has a planar shape and a greater sectional area than the moving part 143.

[99] The housing 154 is coupled into the groove 1 disposed in a longitudinal direction of the guide rail 2 forming a door sill, through bolts 172 and 173 that cross the groove 1 from an outer surface of the guide rail 2.

[100] A receiving portion, having a space allowing the flange 145 to vertically move, is disposed in the housing 154. The housing 154 includes both side surfaces 146 and 147 and a connecting surface 148. The both side surfaces 146 and 147 have semicircular outer surfaces. The connecting surface 148 connects the side surfaces 146 and 147. A tetragonal through hole 149 is disposed at a top point of the connecting surface 148. The tetragonal through hole 149 communicates with the inner space defined by the receiving portion and has a smaller area than the flange 145. Thus, a connecting portion is disposed between the tetragonal through hole and the receiving portion, and stop flanges 150 and 151 hook the flange 145 to limit a raised height of the moving part 143.

[101] Through holes 175 and 176 are disposed in an outer vertical surface 174 of the guide rail 2. The through holes 175 and 176 allow the bolts 172 and 173 crossing the groove 1 to pass through holes of sidewalls 177 and 178 defining the groove 1. Threads are disposed in inner circumferences of through holes 179 and 180 disposed in the sidewall 178. The threads engage with threads disposed in ends of the bolts 172 and 173. Through holes 152 and 153 through which the bolts 172 and 173 pass, are disposed in the housing 154.

[102] To couple the locking device 140 according to the embodiment illustrated in FIG. 14 to the guide rail 2, the moving part 143 with the fixing plate 142 disposed thereon is firstly inserted into the through hole 149 disposed in the connecting surface 148 of the housing, and then the flange 145 is coupled to a bottom end of the moving part 143 using the screw 144. Then, the housing 154 with the operating member 141 is placed in the groove 1 of the guide rail 2 such that the through hole 149 is disposed in an upper region, and the housing 142 is coupled to the guide rail 2 through the bolts 172 and 173.

[103] To couple the housing 154 to the guide rail 2 using the bolts 172 and 173 crossing the groove 1, through holes or bolt holes are disposed in the sidewalls 177 and 178

defining the groove 1 of the guide rail 2 and are spaced the same distance as that between the through holes 152 and 153 disposed in the housing 154. After that, the housing 154 is placed, and the bolts 172 and 173 are inserted into the through holes to simply couple the locking device 140. Thus, the construction is very convenient.

[104] As such, the locking device 140 is disposed on the guide rail 2. The plate hook 36 of the push-resistant device 30 disposed on a door is inserted below the fixing plate 142 of the locking device 140 when the door is closed. When the push-resistant device 30 exerts a raising force on the fixing plate 142, the fixing plate 142 is raised, but the flange 145 limits the raised height. Thus, the plate hook 36 of the push-resistant device 30 is locked in a space defined by the groove 1 and the fixing plate 142.

[105] Longitudinal ends of the fixing plate 142 have inclined bottoms to allow the push- resistant device 30 to be inserted without friction.

[106] Also, according to the embodiment of FIGs. 14 through 17, the housing has a semicircular shape to prevent the accumulation of foreign objects, but it is not limited thereto, and an inclined surface having a predetermined angle or a vertical surface may be provided.

[107] According to the embodiments, although the push-resistant device 30 is disposed on the lower portion of the door, and the locking device 40 is disposed in the groove 1 of the guide rail 2, it has the same effect that the locking device 40 is disposed on the lower portion of the door, and the push-resistant device 30 is disposed in the guide rail 2. When the push-resistant device 30 is disposed in the guide rail 2, the plate hook 36 protrudes in an opposite direction to the moving direction of the door.