[Description of the Related Art] Generally, a hinged door comprises a doorframe for supporting a door, and a supporting member for securing the door onto the doorframe, so that the door is rotatable on the doorframe. A portion, whereby the door is rotatably supported in the doorframe and is secured in the doorframe, is called a hinged portion. The hinged portion is provided between the contacting points of the door and doorframe, in order to rotatably support the door on the doorframe. If the door is pushed or pulled, the door rotates about the hinged portion to open and close the entrance.

Such a hinged door is opened and closed by artificial manipulation of an operator, and may be designed to be closed by a hydraulic pressure or a biasing power of a spring.

Considering convenience in operating a door, diverse sliding type doors have been proposed. This type of sliding door includes a driving device for

operating the door by means of a hydraulic cylinder or a rotator, and a controller for controlling the operation of the driving device to close and open the door.

Since the above-described sliding-type apparatus can automatically open and close the door using diverse position information of the coming and going persons, any inconvenience in opening and closing the door may be reduced. In particular, the above-described apparatus is adopted to the sliding door, but not adopted to the hinged door.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems involved in the related art, and to provide an automatic opening and closing apparatus for a hinged door.

It is another object of the present invention to provide an automatic opening and closing apparatus for a hinged door, in which a hinged portion supporting the hinged door on a doorframe is set as a rotating center of the door without using a separate construction.

In order to achieve the above objects, there is provided an apparatus for opening and closing a hinged door rotatably supported on a doorframe by hinged sections, the apparatus comprising: a frame for enclosing at least one of the hinged sections; a driving section, connected to a portion of the frame corresponding to the hinged section, for generating a rotating force to rotate the frame; a supporting

section for supporting the frame on the driving section as a floating mechanism and for transferring the rotating force of the driving section to the frame and the hinged door; and a plurality of elements for detecting the position of the hinged door.

The driving section for generating a rotating force is positioned under the doorframe. The supporting section includes a beam structure connecting a rotating shaft of the driving section to the door and engaged to the frame to transfer the rotating force to the door, and a support for maintaining an engaging position among the beam structure, the driving motor, and the door to be positioned in a rotating center of the rotating shaft of the driving motor.

The supporting section includes a rotating bush, mounted on the rotating shaft, for eliminating a rotating friction between the doorframe and the shaft, and a thrust bearing for supporting a vertical loading to be transferred to the bush through the shaft.

BRIEF DESCRIPTION OF THE DRAWINGS The above objects, other features and advantages of the present invention will become more apparent by describing the preferred embodiment thereof with reference to the accompanying drawings, in which: FIG. 1 is a perspective view illustrating the construction of an automatic opening and closing apparatus for a hinged door according to the present invention.

FIG. 2 is a detailed view illustrating the major parts of an automatic opening and closing apparatus for a hinged door according to the present invention.

FIG. 3 is a longitudinal cross-sectional view illustrating main parts of an automatic opening and closing apparatus for a hinged door according to the present invention.

FIG. 4 is a view illustrating the driving section of a hinged door according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION The construction and operation of the present invention will be explained in detail with reference to the accompanying drawings.

The automatic opening and closing apparatus for a hinged door according to the present invention comprises a hinged door 1, a doorframe 2 rotatably supporting the hinged door 1, and a sensing device for sensing the position of the door 1.

The hinged door includes a manual hinged portion 3, of which one of upper and lower portions supports the door 1 on the doorframe 2. The other of the hinged portion 3 supporting the door is consisted of a driving section 4, and the driving section 4 comprises a driving motor 5, positioned under the doorframe, for providing rotating force to the door, a beam structure 8 connecting a shaft 6 of the

driving motor 5 to the door 1 and engaged to a frame 7 by a support 9 for transferring the rotating force produced form the center of the shaft to the door, and a supporting section for maintaining the engaging position of the door 1, the driving motor 5 and the beam structure 8 to be positioned in a rotating center of the shaft 6 of the driving motor 6.

The driving section 4 is positioned on the lower frame 7 of the doorframe 2 supporting the door 1. A rotating bush 10 is mounted on the shaft by the supporting section to eliminate the rotating friction between the doorframe 2 and the shaft 6. The rotating bush 10 is supported by a thrust bearing 11 to support the vertical loading to be transferred to the bush through the shaft 6. A damping bush may be interposed between the rotating bush 10 and the thrust bearing 11.

The sensing device for detecting the position of the door 1 controls the opening and closing time of the door 1 and the rotation of the driving motor 5, and comprises sensors S 1 to S4, arranged in upper and lower portions of the doors, for determining the opening and closing time of the door 1, and a sensor S5, provided adjacent to the driving motor, for controlling an amount of a sector of the door by supplying the detected signal to the controller, the amount of sector being produced due to the rotating amount of the shaft 6.

As shown in FIG. 1, the door 1 is consisted of the hinged portion 3 supporting the upper end of the door, and the driving section 4 for automatically rotating the door 1, thereby automatically controlling the rotating time and the

rotating angle of the door.

In the driving section 4, the driving motor 5 has a reduction mechanism is supported by the hinged portion 3, and the shaft 6 of the driving motor 5 forms a rotating axis of the door 1 with a lower portion of the door 1 being supported on the doorframe 2 or a floor structure. With the construction, since the load of the door 1 acts on the shaft 6, the rotation of shaft 6 and the load of door 1 are supported by the thrust bearing 11, thereby preventing the mechanical wear from being produced due to the shaft load acting on the shaft 6. The rotating bush 10 provided on the upper portion of the thrust bearing 11 reduces the friction produced between the shaft 6 and the doorframe 2 and the rotating resistance of the shaft 6.

With the construction having the hinged portion 3, the driving section 4 and the sensors S1 to S5, if the driving motor 5 is applied with an electrical power, the driving motor 5 rotates in a predetermined rotating speed and rotating angle, and the controller controls the door by the detecting signals of the sensors.

The rotating force of the driving motor 5 is transferred to the door 1 through the shaft 6. Since the door 1 is provided on a lower end thereof with the beam structure, and since the end of the beam structure is engaged with the shaft 6, the rotating force of the driving motor 5 is evenly distributed across the wholly region of the lower end of the door 1 through the beam structure 8. In other words, the rotating force of the driving motor 5 is not transferred to the door 1 directly, but is transferred to the door 1 through the beam structure positioned on

the lower end of the door. This uses a principle of the leverage by the beam structure having a cantilever type, so that the force needed to rotate the door may be reduced. Therefore, a small driving motor can be used to sufficiently rotate the weighted door.

The shaft 6 is engaged to the beam structure 8 and is positioned in a position on that the vertical load is applied. The thrust bearing 11 supports the load of the door 1, and the rotating bush 10 reduces the friction of the shaft.

Referring to FIG. 4, the sensors S 1 and S2 are used for detecting incoming and outgoing persons, and the sensors S3 and S4 are used for detecting the stopping position and rotating direction of the door. Supposing that a left rotation of the motor means an inward open of the door and a right rotation of the motor means an outward open of the door, the opening and closing of the door and the control of the driving section are as follows: When a person is coming in, the motor 5 rotates in a left direction response to the detecting sensor S1, so that the door 1 is inwardly opened. At that time, the detecting sensor S3 is off immediately, and the detecting sensor S4 is off when the door becomes out of the detecting position.

Since the off time of sensor S3 is faster than that of the sensor S4, the controller determines that the door is inwardly opening (i. e., the motor is rotating in a left direction).

The door moves to a predetermined position by the control of the sensor S5. In case a person has been come in, even though the sensor Sl is off and the sensor S2 is on, the door moves continuously to the predetermined position.

During the opening, when the sensor S2 is off, the door moves to its original position until the sensors S3 and S4 are on.

During the closing, if a person is going out, the sensor S2 is on to stop the closing of the door and to restart the opening of the door to the predetermined position.

In case persons are coming in and going out simultaneously, the door is operated by a signal of the first detecting sensor of the sensor S 1 or S2.

When a person is going out, the motor 5 rotates in a right direction response to the detecting sensor S2, so that the door 1 is outwardly opened. At that time, the detecting sensor S4 is off immediately, and the detecting sensor S3 is off when the door becomes out of the detecting position.

Since the off time of sensor S4 is faster than that of the sensor S3, the controller determines that the door is outwardly opening (i. e., the motor is rotating in a right direction).

The door moves to a predetermined position by the control of the sensor

S5. In case that a person has been went out, even though the sensor S2 is off and the sensor Sl is on, the door moves continuously to the predetermined position.

During the closing, when the sensor S2 is off, the door moves to its original position until the sensors S3 and S4 are on.

During the closing, if a person is coming in, the sensor S 1 is on to stop the closing of the door and to restart the opening of the door to the predetermined position.

The system of controlling the opening and closing of the door by using the detecting sensors may be altered depending upon the condition.

With the construction, since the hinged door is rotated by using a principle of leverage, the door can be operated by a small power, and the operating noise can be reduced. In addition, the present invention can be easily adopted to the rotating shaft of the prior art hinged doors.

Although the present invention has been described with reference to the drawings, it is understood that this description is not to limit the invention to the embodiment shown in the drawings but simply to explain the invention. One skilled in the art will understand that various changes and modifications can be made from the embodiments disclosed in the specification. Therefore, the scope of the present invention should be defined by the appended claims.