Door Hinge

The present invention relates to a door hinge for use in installing, for example, a conventional building door or a fireproof-door or an emergency door in a fireproof-shutter, especially being capable of automatically closing the door and controlling the closing speed.

There are basically two types of known hinges. The first one, for-example such as the common door hinges, allows a door to swivel around a hinge-shaft without any auto-close function. The second one, for example such as the one discussed in Japanese Patent Appln. No, Sho 64-309942, has an auto-close function provided by a simple spring means. However, the former is disadvantageous in that in order to provide a door to be installed with an auto-close function an expensive and bulk door-closer should be additionally mounted door. The latter has the problem of impact noise whenever the door closes. Also the door may injure passers-by due to its uncontrolled closing speed.

The present invention is to provide a door hinge that will not only automatically close the door, but also control the speed of the door closing so that the opened door can always be automatically and smoothly closed without any noise.

According to the invention, this purpose can be accomplished by providing a buffer means as well as a coil-spring between a first hinge part and a second hinge part which are pivotably mounted on a hinge-shaft.

The hinge according to the present invention is characterized in that it comprises the first hinge part, the second hinge part, a hinge-shaft on which the two hinge parts are pivotably mounted, a spring means for returning the second hinge part to a predetermined position relative to the first hinge part, and a buffer means arranged between the first and the second hinge parts.

Further, the hinge is characterized in that one part of the buffer means is pivotably connected to the first hinge part and another part of the buffer means is pivotably connected to an extended part of the second hinge part.

Further, the hinge is characterized in that its buffer means comprises a cylinder and a piston, said cylinder having a by-pass that communicates with the main chamber of the cylinder through a plurality of fluid passages.

FIG. 1 is a perspective view of the door hinge according to the present invention,

FIG. 2 is a cross-sectional view of the buffer assembly incorporated into the FIG. 1,

FIG. 3 is a cross-sectional view of the FIG. 1 when the door is closed,

FIG. 4 is a cross-sectional view of the FIG. 1 when the door is opened, and FIG. 5 shows an exploded view of the hinge shown in FIG. 1.

As shown in the drawings, the hinge according to the present invention comprises two hinge parts (10) and (20) and a hinge-shaft (30) on which the above two hinge parts are pivotably mounted.

In this hinge, a spring (S) is provided on the hinge-shaft (30) for returning the second hinge part (20) to which the door is to be fixed to a predetermined position in relation to the first hinge part which is to be fixed to the wall. A buffer assembly (40) is arranged between the two hinge parts (10) and (20) for controlling the returning speed of the second hinge part (20).

The buffer means (40) comprises a cylinder (41) and a piston (44). The rear end part of the cylinder (41) is pivotably connected to the first hinge part (10) through a pin (50), while the front end part of the piston (44) is pivotably connected to the extended part (21) of the second hinge part (20) through a pin (22).

The cylinder (41) is provided with a by-pass channel (43) on one side of its main chamber (42). The by-pass (43) communicates with the main chamber (42) through three fluid-passages (43a), (43b), (43c), the first one (43a) of which is arranged near the bottom side (in the drawings, left end side) of the chamber (42), the third one (43c) near the toy side (in the drawings, right end side) of the chamber (43), and the second one (43b) near the first fluid-passage (43a). Further, the cylinder (41) is provided with an adjusting screw (60) for adjusting the opening of the second fluid-passage (43b).

On the head of the piston (44), a plurality of holes (45) and a valve member (46) are arranged. The valve member (46) is arranged on the head of the piston (44) in such a manner that it prevents the working fluid (L) filled in the cylinder (41) from passing through the holes (45) when the piston (44) is in a backward movement, and allows the working fluid (L) to freely pass through the holes (45) when the piston (44) is in a forward movement.

With the above arrangement, the hinge can not only pivotably support a door as a conventional one does but also automatically and smoothly close the opened door by the spring means (S) and the buffer means (40).

In operation, FIG. 3 shows the closed condition of the door engaged and FIG. 4 shows the opened condition of the door engaged. When the door is being closed from the condition of FIG. 4 to that of FIG. 3 by the force of the spring means (S), the piston (44) has to move into the cylinder (41) pushing through the working fluid (L) in the cylinder. At this moment, the vane member (46) comes to close the holes (45) in the head of the piston (44) by the pressure of the working fluid (L), whereby the working fluid (L) in the main chamber (42) of the cylinder (41) flowing into the by-pass (43) through the first and second fluid-passages (43a), (43b), and the working fluid (L) in the by-pass (43) flowing into the main chamber (42) of the cylinder (41) through the third fluid passage (43c). Under this condition, the moving speed of the piston (44) depends upon the flowing speed of the working fluid (L) in the cylinder (41). Consequently, the closing speed of the door engaged can be slowed down by the working fluid (L) and controlled to a suitable degree by adjusting the flowing mount of the fluid through the by-pass (43) by means of the screw (60).

In the above operation, some amount of the working fluid (L) in the main chamber (42) of the cylinder (41) will flow into the by-pass (43) through the first and second fluid-passages (43a) (43b) until the piston head arrives at the position of the second fluid-passage (43b), whereby the door engaged will be relatively rapidly closed, while less amount of the fluid than the above will flow into the by-pass (43) only through the first fluid-passage (43a) after the piston has passed over the position of the second fluid passage (43b), whereby the door engaged being more slowly closed. Accordingly, with the above hinge, the door engaged can be closed as fast and smoothly as possible in the beginning of its closing movement, and can be more slowly closed in the end of its closing movement.

On the other hand, when the door is being opened as in FIG. 4, the valve member (46) on the piston head will open the holes (45) to allow the working fluid (L) in the chamber (42) to freely pass through the holes (45).

Consequently, the door can be easily opened regardless of the buffer assembly (40).

In the embodiment shown in FIGS. 1-5, the first hinge part defines a recess 52, which may be a hole as shown. The cylinder 41 is pivoted to swing into and out of the recess 52. The second hinge part has the extended part 21 pivotally connected to the outer end of said piston rod 44. The first hinge part has a slot 54 formed therein for receiving the extended part 21 when the hinge is in the closed position. Two torsion springs S are used in the embodiment shown, as particularly illustrated in FIG. 5.

In the embodiment illustrated, the second hinge part 20 includes three parallel portions 56, 58, 60, which define two openings 62, 64. The first hinge part includes two parallel portions 66, 68 which nest within the two openings 62, 64. The second hinge part has opposite faces, only one of which, 70, is shown in FIG. 5. The extended part 21 extends laterally from the face 70. The first hinge part has opposite faces, only one of which, 72, is shown in FIG. 5. The slot 54 is formed within the face 72 of the first hinge part.

With the above ideal arrangements, the hinge according to the present invention further has the advantages of providing the required operations without fall at all times and of being as compact as possible.

The hinge according to the present invention described above can be advantageously employed in installing a building door, or a fireproof-door, or an emergency door in a fireproof-shutter.