Description

DOOR CLOSER FOR FIRE DOOR

Technical Field

[1] The present invention relates to a door closer for a fire door, and more particularly, to a door closer for a fire door that is capable of rapidly and firmly closing the fire door in conformity with the requirements of the fire door when a fire occurs and is capable of easily and gently opening the fire door in normal states. Background Art

[2] Fig.1 is a perspective view showing a conventional door closer for a fire door.

[3] Generally, a fire door, which is installed in a concrete building, has a door closer adapted to gently open and close the fire door and also to perform fire-protection functions required for observing the rules for the prevention and extinction of fires. The door closer largely includes a body 10 and an auxiliary part 20.

[4] According to the rules for prevention and extinction of fires recently revised, by the way, it is strongly recommended that the fire door should be automatically closed, and thus, the auxiliary part 20 of the door closer has a function of strengthening the force for closing the fire door by overcoming the difference between indoor and outdoor pressures. At this time, however, it should be considered that the door closer should rapidly and firmly close the fire door when a fire occurs and at the same time easily and gently open the fire door in normal states with an external force of 6ON or less.

[5] However, the conventional door closers do not perform the both functions mentioned above. So as to conform the revised rules for protection and extinction of fires, that is, the size of the door closer should be more increased by about 1.5 times to 2 times than the conventional one of the door closer, and in this case, when the size of the door closer is increased, the fire door is gently closed by the reinforcement of the indoor pressure. To the contrary, the force required for opening the fire door becomes increased in normal states, thereby unfortunately making it difficult for the old, the disabled, and children to open the fire door. Disclosure of Invention

Technical Problem

[6] 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 a door closer for a fire door that is capable of rapidly and firmly closing the fire door in conformity with the requirements of the fire door when a fire occurs and is capable of easily and gently opening the fire door in normal states. Technical Solution

[7] To achieve the above object, according to the present invention, there is provided a door closer for a fire door adapted to rapidly and firmly closing the fire door when a fire occurs and adapted to easily and gently open the fire door in normal states, the door closer including: a body; and

[8] an auxiliary part connected to the body by means of a bracket, the auxiliary part having an operator disposed at the inside of a housing by means of a spring and having a groove formed on the front end thereof, a ball member housed into the groove formed on the operator in such a manner as to be linearly moved therealong, and an operating cylinder adapted to guide the ball member linearly moving on the operator to first to third sliding pathways formed thereon so as to change a door-rotating force caused by the body to multiple steps.

[9] According to the present invention, desirably, the operating cylinder has the first to third sliding pathways each having a groove having a predetermined width formed along the outer peripheral surface thereof, the grooves of the first to third sliding pathways being connected to each other to a scoop-like shape so as to guide the circulating movement of the ball member, the first sliding pathway having a predetermined constant depth, the second sliding pathway being slowly increased in depth until it reaches a first descending protrusion formed thereon, and the third sliding pathway being slowly decreased in depth after it is drastically increased in depth and communicating with the first sliding pathway or the second sliding pathway by means of a second dropping protrusion formed thereon.

[10] According to the present invention, desirably, the operating cylinder has a cut surface or a stopper adapted to restrict the moving range of the ball member.

Advantageous Effects

[11] According to the present invention, the door closer for a fire door is capable of rapidly and firmly closing the fire door in conformity with the requirements of the fire door when a fire occurs and is capable of easily and gently opening the fire door in normal states.

Brief Description of Drawings

[12] FIG.1 is a perspective view showing a conventional door closer for a fire door.

[13] FIG.2 is an exploded perspective view showing a door closer for a fire door according to a first embodiment of the present invention.

[14] FIG.3 is an exploded and enlarged perspective view showing the main parts of FIG.2.

[15] FIG.4 is a separated enlarged perspective view showing the operating cylinder of

FIG.3. [16] FIG.5 is a perspective view showing the operating cylinder of a door closer for a fire door according to a second embodiment of the present invention.

[17] FIG.6 is a perspective view showing the operating cylinder of a door closer for a fire door according to a third embodiment of the present invention.

[18] FIG.7 is a perspective view showing the assembling and operating states of the door closer for a fire door according to the present invention. Mode for the Invention

[19] An explanation on a door closer for a fire door according to the preferred embodiments of the present invention will be given in detail with reference to the attached drawings.

[20] FIG.2 is an exploded perspective view showing a door closer for a fire door according to a first embodiment of the present invention, FIG.3 is an exploded and enlarged perspective view showing the main parts of FIG.2, and FIG.4 is a separated enlarged perspective view showing the operating cylinder of FIG.3.

[21] The present invention relates to a door closer for a fire door adapted to rapidly and firmly closing a fire door when a fire occurs and adapted to easily and gently open the fire door in normal states. Generally, a fire door is openable up to 180° and is slowly closed in a range between 15° and 20° with a strong force. However, since the conventional door closers do not have substantially strong closing force, the fire doors on which the door closers are installed are not closed well. Thus, the operating force of the door closer is increased to close the fire door well, but if it is desired to open the fire door, a relatively strong force should be required, which gives many inconveniences to users. According to the present invention, the door closer has a body 10 and an auxiliary part 30 connected to the body 10 by means of a bracket 15.

[22] According to the present invention, an operator 35 having a groove 35a formed on the front end thereof is mounted at the inside of a housing 31 by means of a spring 32. In the same manner as the operator 35 as shown in FIG.l, the operator 35 of the door closer according to the present invention is elastically supported by the spring 32 and a cap 23. However, the operator 35 of the door closer according to the present invention includes the groove 35a having predetermined width and depth formed on the front end thereof, and in this case, the front end surface of the operator 35 is slantly formed to come into outer contact with an operating cylinder 40 as will be discussed later.

[23] According to the present invention, further, a ball member 38 is housed into the groove 35a of the operator 35 in such a manner as to be linearly moved along the groove 35a. In conventional practice, the operator 25 and an operating plate 24 constitute a cam mechanism, and to the contrary, according to the present invention, the operator 35 and the operating cylinder 40 constitute a cam mechanism by means of the ball member 38. Accordingly, since a relatively strong operating force is applied to the ball member 38, the ball member 38 should need predetermined strength and

hardness equal to the operator 35 and the operating cylinder 40. The linear movement of the ball member 38 along the groove 35a of the operator 35 is connected to first to third sliding pathways 42, 44 and 46 formed on the operating cylinder 40 as will be discussed below.

[24] According to the present invention, moreover, the operating cylinder 40 is adapted to guide the ball member 38 linearly moving on the operator 35 to the first to third sliding pathways 42, 44 and 46 so as to change a door-rotating force caused by the body 10 to multiple steps. The operating cylinder 40 includes the first to third sliding pathways 42, 44 and 46 adapted to cause a cam motion like the conventional operating plate 24 so as to adjust the elastic force applied to the body 10 and the door. Each of the first to third sliding pathways 42, 44 and 46 has a groove having a predetermined width formed along the outer peripheral surface thereof, and the grooves of the first to third sliding pathways are connected to each other to a scoop-like shape so as to guide the circulating movement of the ball member 38. In the scoop-like shape, the first sliding pathway 42 becomes a handle portion, and the second sliding pathway 44 and the third sliding pathway 46 are connected to each other to a circular shape. In the scoop-like shape of the first to third sliding pathways 42, 44 and 46, the ball member 38 is passed through the first sliding pathway 42, the second sliding pathway 44 and the third sliding pathway 46, and the ball member 38 is then returned to the first sliding pathway 42. The processes are repeatedly performed.

[25] According to the present invention, at this time, the first sliding pathway 42 has a predetermined constant depth, the second sliding pathway 44 is slowly increased in depth until it reaches a first descending protrusion 45 formed thereon, and the third sliding pathway 46 is slowly decreased in depth after it is drastically increased in depth and communicates with the first sliding pathway 42 or the second sliding pathway 44 by means of a second dropping protrusion 47 formed thereon. The formation of the constant depth of the first sliding pathway 42 gives no influence on the displacement of the operator 35, such that a predetermined constant operating force is applied to the body 10. The slow increase of the depth of the second sliding pathway 44 until it reaches the first descending protrusion 45 allows a closing force to a predetermined angle when the door is closed to be increased. After that, as the ball member 38 is passed through the first descending protrusion 45, the depth of the third sliding pathway 46 is drastically increased up to the lowest point, such that the door is strongly closed and stopped. When the door is opened, next, the ball member 38 is moved from the lowest point on the third sliding pathway 46 and is gently raised, thereby giving no large load to the opening force for the door. After that, if the door is almost opened, the ball member 38 is passed through the second dropping protrusion 47 and reaches the first sliding pathway 42 or the second sliding pathway 44, thereby being returned to its

original state.

[26] Like this, while the closing and opening of the door are being repeatedly performed, the ball member 38 is circulated along the first to third sliding pathways 42, 44 and 46 of the operating cylinder 40, which allows the displacement of the operator 35 through the spring 32 to be varied, thereby appropriately increasing and decreasing an auxiliary operating force to the body 10.

[27] FIG.5 is a perspective view showing the operating cylinder of a door closer for a fire door according to a second embodiment of the present invention, and FIG.6 is a perspective view showing the operating cylinder of a door closer for a fire door according to a third embodiment of the present invention.

[28] The operating cylinder 40 includes a cut surface 55 or a stopper 65 adapted to restrict the moving range of the ball member 38. The cut surface 55 as shown in FIG.5 is formed by removing a portion where the ball member 38 is not moved, which provides the saving of the material upon mass production. The stopper 65 as shown in FIG.6 serves to restrict the moving range of the ball member 38, thereby preventing the malfunction of the ball member 38. Of course, the both configurations of FIGS.5 and 6 may be adopted.

[29] FIG.7 is a perspective view showing the assembling and operating states of the door closer for a fire door according to the present invention.

[30] According to the present invention, the operating cylinder 40 is mounted at the inside of the housing 31, and the operator 35 is disposed in a linear direction on the outer peripheral surface of the operating cylinder 40 by means of the ball member 38. When the rotating displacement (that is, an operating force) of the body 10 is varied according to the opening and closing of the door, the operating cylinder 40 is cooperatively operated with the body 10, thereby causing the variation of the rotating displacement of the body 10. The variation of the rotating displacement causes the elastic force of the operator 35 and the spring 32 to be varied through the ball member 38 housed into the first to third sliding pathways 42, 44 and 46 of the operating cylinder 40. The first to third sliding pathways 42, 44 and 46 of the operating cylinder 40 are formed to multiple depths so as to execute a set cam profile and are connected to the ball member 38 and the operator 35, thereby making it possible to perform substantially complicate control.

[31] On the other hand, the door-closing force should be strong and the door-opening force should be applied to 5.5kg (60N) or less, so as to observe the revised rules for protection and extinction of fires. In conventional practices, the above-mentioned conditions are not satisfied, but according to the present invention, the door-closing force is strengthened in a predetermined section (in a range between 15° and 20° just before closing), while the door-opening force is being gently maintained.

[32] 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.