Background Art Generally, tempered glass is made by heating an outer surface of the glass to about 500~600°C, that is, to a glass softening temperature, and, thereafter, quenching the heated glass, thus compressively straining the outer surface of the glass, and tensile straining the interior thereof. To provide tempered glass doors, tempered glass is coupled to a door frame, and the door frame is rotatably coupled to both a door sash and a hinge shaft of a hinge device which is fastened to a support surface. Then, the openable tempered glass door is provided.

A representative example of such a tempered glass

door mounted on a support surface is shown in FIG. 1.

In FIG. 1, the reference numeral 1 denotes a tempered glass pane, 2 denotes a door frame, 3 denotes a door sash, 4 is a hinge shaft, and 5 is a hydraulic hinge device.

As shown in FIG. 1, to provide a tempered glass door in a building, the tempered glass pane 1 is fastened to the door frame 2. The door frame 2 having the tempered glass pane 1 is rotatably coupled between the hinge shaft 4, which is provided on an upper part of the door sash 3 built in a wall of the building, and a hinge shaft of the hydraulic hinge device 5 which is mounted in a support slab of the building.

However, the conventional tempered glass door has the hydraulic hinge device 5 to provide a structure such that the door automatically closes when in an open state.

Therefore, the conventional tempered glass door is disadvantageous in that, when a user opens the door, a large force is required. Furthermore, if several people continuously pass through the door, a following person may be hurt by the door closing due to the strong restoring force of the hydraulic hinge device 5. Particularly, this is a serious risk factor for old or feeble persons and children.

In addition, in the tempered glass door having the conventional hydraulic hinge device, a spring provided in the hydraulic hinge device may weaken, or leakage of fluid, provided in the hydraulic hinge device, may occur after the

door is opened and closed a large number of times. Due to this, a gap occurs between the door frame and the door sash, so that outside air or dust undesirably enters into the building through the gap. As well, to repair the door in which the gap occurs, expensive costs are incurred. As such, the door having the conventional hydraulic hinge device is disadvantageous in that maintenance costs are increased.

Moreover, to mount the hydraulic hinge device in the support slab, a predetermined space must be defined in the support slab. Therefore, the door having the conventional hydraulic hinge device is problematic in that a door mounting process is very complex, thus being inconvenient.

Disclosure of the Invention Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a hinge device for doors by which a door can be mounted on a support surface without defining a separate hinge device seat in the support surface, unlike conventional hydraulic hinge devices, and which is operated by a bearing, so that the door is easily opened and closed using a small force, and which is capable of maintaining an opened or completely closed state of the door.

Another object of the present invention is to provide

a hinge device for a door in which, when the door is in neither a completely opened state nor a completely closed state, the door is inclined by a height of a part of a ball bearing protruding from a lower surface of the door, so that the door is automatically closed due to the weight of the door.

In order to accomplish the above object, the present invention provides a hinge device for doors, including : a hinge unit, having a support plate seated in a predetermined portion of a support surface on which a door is mounted, a plurality of plate fastening holes provided at predetermined positions in the support plate to fasten the support plate to the support surface, a hinge shaft provided on a central portion of the support plate, a pair of door open state maintenance holes provided on the support plate on opposite sides of the hinge shaft, a door closed state maintenance hole provided on the central portion of the support plate in front of the hinge shaft, with a guide groove provided on opposite sides of the door closed state maintenance hole, and a plurality of plate position adjusting holes provided on the support plate at predetermined positions on opposite sides and in front of the door closed state maintenance hole; a bearing unit, having a hinge shaft bearing fitted over the hinge shaft of the hinge unit, and a ball bearing to roll on the support plate while the door is opened or closed; a main body, having a hinge shaft hole provided at a predetermined position in the main body, so that the hinge shaft, over

which the hinge shaft bearing is fitted, is inserted into the hinge shaft hole, a ball bearing seat provided at a predetermined position in the main body, so that the ball bearing is inserted into the ball bearing seat, a stepped upper part provided at an upper portion of the main body over both the hinge shaft hole and the ball bearing seat, with a position adjusting hole longitudinally provided in the stepped upper part, and a pair of door frame fastening slots provided on each of opposite ends of the main body; and a position adjusting part, having a position adjusting plate, with a position adjusting seat defined under the position adjusting plate by bending the position adjusting plate, so that the stepped upper part of the main body is movably seated in the position adjusting seat, and a position adjusting bolt tightened into the position adjusting hole of the stepped upper part through the position adjusting plate, so that the position adjusting plate is coupled to the main body.

Brief Description of the Drawings The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. 1 is a sectional view showing a conventional hinge device for doors ;

FIG. 2 is a perspective view of a hinge device for doors, according to an embodiment of the present invention ; FIG. 3 is a sectional view of the hinge device of FIG. 2; FIG. 4 is a perspective view showing a hinge unit of the hinge device of FIG. 2 ; and FIG. 5 is a front view showing a part of a door in which the hinge device of FIG. 2 is mounted.

Best Mode for Carrying Out the Invention Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a perspective view of a hinge device for doors, according to an embodiment of the present invention.

FIG. 3 is a sectional view of the hinge device of FIG. 2.

FIG. 4 is a perspective view showing a hinge unit 10 of the hinge device of FIG. 2. FIG. 5 is a front view showing a part of a door in which the hinge device of FIG. 2 is mounted.

As shown in FIGS. 2 through 5, the hinge device for doors according to the embodiment of the present invention includes the hinge unit 10 which is fastened to an upper surface of a support slab of a building on which a door is mounted.

The hinge unit 10 to be fastened to the support slab

of the building has a support plate 11, and a plurality of plate fastening holes 12 which are provided at predetermined positions in the support plate 11 to fasten the support plate 11 to the support slab. The hinge unit 10 further has a hinge shaft 13 which is provided on a central portion of the support plate 11, and a pair of door open state maintenance holes 14 which are provided on the support plate 11 on opposite sides of the hinge shaft 13.

The hinge unit 10 further has a door closed state maintenance hole 16 which is provided on the central portion of the support plate 11 in front of the hinge shaft 13. A guide groove 15 is provided on both sides of the door closed state maintenance hole 16.

The hinge unit 10 further has a plurality of plate position adjusting holes 17 which are provided on the support plate at predetermined positions on both sides and in front of the door closed state maintenance hole 16.

The hinge device of the present invention further includes a bearing unit 20 to help the door be rotatably mounted on the hinge unit 10. The bearing unit 20 has a hinge shaft bearing 21 which is fitted over the hinge shaft 13 of the hinge unit 10, and a ball bearing 22 to roll on the support plate 11 while the door is opened or closed.

The hinge device further includes a main body 30 to receive therein the hinge shaft bearing 21 and ball bearing 22 of the bearing unit 20.

The main body 30 has a hinge shaft hole 31 which is

provided at a predetermined position in the main body 30, so that the hinge shaft 13 is inserted into the hinge shaft hole 31. The main body 30 further has a ball bearing seat 32 which is provided at a predetermined position in the main body 30, so that the ball bearing 22 is inserted into the ball bearing seat 32.

The main body 30 further has a stepped upper part 34 which is provided at an upper portion of the main body 30 over both the hinge shaft hole 31 and the ball bearing seat 32, with a position adjusting hole 33 longitudinally provided in the stepped upper part 34. A pair of door frame fastening slots 35 is provided on each of opposite ends of the main body 30.

The hinge device further includes a position adjusting part 40 which is coupled to the stepped upper part 34 of the main body 30 through the position adjusting hole 33.

The position adjusting part 40 has a position adjusting plate 43 which is movably coupled to the stepped upper part 34 of the main body 30 by a position adjusting bolt 41.

In detail, a position adjusting seat 42 is defined under the position adjusting plate 43 by bending the position adjusting plate 43, so that the stepped upper part 34 of the main body 30 is movably seated in the position adjusting seat 42. Therefore, the position adjusting plate 43 is coupled to the main body 30 by the position adjusting

bolt 41 tightened into the position adjusting hole 33 of the stepped upper part 34 through the position adjusting plate 43.

The operation and effect of the hinge device of the present invention having the above-mentioned construction will be described herein below.

The support plate 11 of the hinge unit 10 is fastened to a support slab of a building through plate fastening holes 12.

To align the hinge unit 10 with a door mounting position, the support plate 11 is movably fastened to the support slab through the plate position adjusting holes 17.

As such, while the support plate 11 is fastened to the support slab, the position of the support plate can be appropriately adjusted.

Thereafter, the main body 30 is placed on the support plate 11 of the hinge unit 10 such that the hinge shaft 13 of the hinge unit 10 is inserted into the hinge shaft hole 31 of the main body 30. Then, the main body 30 becomes rotatable around the hinge shaft 13 by the support of the hinge shaft bearing 21 interposed between the hinge shaft 13 and the main body 30.

The main body 30 is thereafter coupled to a door frame 2. Here, front and rear surfaces of the door frame 2 are inserted into the pair of door frame fastening slots 35 which is provided on each of the opposite ends of the main body 30. Thus, the door frame 2 is reliably fastened to the

main body 30.

In this state, the position adjusting bolt 41 is tightened into the position adjusting hole 33 of the main body 30 through the position adjusting plate 43. When it is desired to adjust the position of the main body 30, the main body 30 is removed from the support plate 11 of the hinge unit 10. Thereafter, the position adjusting bolt 41 is tightened into or loosened from the position adjusting hole 33. Then, the main body 30 is moved to the left or right in the position adjusting seat 42 of the position adjusting plate 43. After the main body 30 has been positioned in the position adjusting seat 42 at a desired position, the main body 30 is again placed on the support plate 11.

As such, the door is mounted through the above- mentioned process including the processes of determining the positions of the hinge unit 10 and main body 30. In the above state, when a user pushes or pulls the door, the door rotates around the hinge shaft 13, so that the door is opened inwards or outwards.

When the door is rotated to a right angle, the ball bearing 22, provided in the main body 30, is inserted into the door open state maintenance hole 14 of the hinge unit 10.

Thus, the door is maintained in the opened state.

To close the door opened at a right angle, the user applies a predetermined force to the door. Then, the ball bearing 22 is dislodged from the door open state maintenance hole 14 of the hinge unit 10. Thus, the door is rotated

around the hinge shaft 13 while the ball bearing 22 rolls on the support plate 11. As a result, the ball bearing 22 is inserted into the door closed state maintenance hole 16 of the support plate 11 along the guide groove 15.

At this time, although the door passes over the door closed state maintenance hole 16 due to the inertia of the door when closed, the ball bearing 22 again rolls towards the door closed state maintenance hole 16 due to the inclination of the guide groove 15. As a result, the ball bearing 22 is inserted into the door closed state maintenance hole 16, so that the door is perfectly closed.

Furthermore, in the present invention, when the ball bearing 22 is removed from the door open state maintenance hole 14, the door becomes inclined by a height of a part of a ball bearing protruding from a lower surface of the door.

Therefore, the ball bearing 22 rolls towards the door closed state maintenance hole 16 due to the weight of the door, so that the door is automatically closed.

Industrial Applicability As described above, the present invention provides a hinge device for doors by which a door can be mounted on a support surface without defining a separate hinge device seat in the support surface, unlike conventional hydraulic hinge devices, and which is operated by a bearing, so that the door is easily opened and closed with a small force,

and which is capable of maintaining an opened or completely closed state of the door. Furthermore, the hinge device of the present invention has a structure in which the door can be automatically closed by the inclination of the door, thus accommodating the effective motion of the door.

Although the preferred embodiment of the present invention has been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.