FIRE LIMITING SCREEN ARRANGEMENT WITH WALK-THROUGH FEATURE

Abstract: A walk-through type fire-limiting screen arrangement IS designed for separating an interior space of a building for preventing fire from propagating and assisting for refugee to escape from fire. The arrangement includes a non-combustible or fire-proof screen drooping from a ceiling or a beam for isolation of an interior space of a building. At least one slit portion is extended vertically down to the lower end of the screen for defining a refugee path. A predetermined width of closure flap portion is associated with the at least one slit for closing the slit portion with a predetermined overlap between the at least one slit portion and the closure flap portion. A main weight bar is horizontally fixed along the lower end of the screen except for the closure flap portion, and a sub-weight bar horizontally fixed along the lower end of the closure flap portion.

Description: BACKGROUND OF THE INVENTION Field of the Invention The present invention relates generally to a fire-limiting and smoke limiting construction for preventing fire from propagating and smoke from diffusing within a building. More specifically, the invention relates to a fire limiting screen arrangement employing a non-combustible or fire-resistive screen formed with a glass fiber fabric or silica cloth or the like, with a walk-through feature permitting people to easily pass through such as disclosed in JPU 23605/1979. Description of the Related Art It has been required to set fire limit zones and smoke limit zones within a relatively large buildings and to further set refugee path so as to prevent fire from propagating and smoke from diffusing, and to facilitate evacuation. In view of this, fire-proof bulkhead, smoke screen, fire shutter, fire retarding door and the like are designedly arranged. As is well known, the fire shutter is a steel shutter having a fire resistant property. Typically, the fire shutter has a construction, in which a plurality of slats are connected via flexible linkages to be rolled up by means of an electric motor or the like. The fire shutter is operative between a state where it is rolled up and stored in the upper portion of the boundary of the fire limit, in the normal state, and a state where it is pulled down or developed to close opening portion of the building at the occurrence of fire. In view of the nature, the fire shutter may not be built-in the fire retarding door. Once the fire shutter is pulled down or developed, people cannot pass through the shutter. In order to certainly provide refugee path for the people, it becomes necessary to provide the fire retarding door in the vicinity of the fire shutter. Typically, the fire retarding door is designed to be automatically closed at the occurrence of fire and can open at any time in the evacuating direction. If a large number of fire-proof bulkheads are provided in various place in the building, fire proofing and smoke-proofing performance can be enhanced. However, it is not practical to provide large number of such fire-proof bulkheads disregarding the original and desired functionality or convenience of use. Furthermore, various factors, such as matching with wall surface in design, storage space in the normal state, easiness of evacuation at emergency, installation cost have to be considered to trouble the designer. SUMMARY OF THE INVENTION The inventors have made extensive research and development for a fire limiting screen arrangement which can be easy to implement with employing a flexible heat resistive and fire-proofing cloth screen at low cost, requires smaller space for storage, demonstrates relatively high fire-proofing and smoke-retarding performance, and can permit people to pass through in the closed condition to facilitate evacuation at emergency. The basic idea of a walk through type fire limiting screen arrangement to separate an interior space of the building by means of fire-proofing screen extending from the ceiling to the floor, and to form one or more slits extending from intermediate height position between the ceiling surface and the floor surface at appropriate positions for providing refugee path. By employing flexible silica cloth as the screen, the slit can be easily widen by hand to permit the people to pass through. Advancing such idea, research and development has been progressed with repeating production of prototype and experimental evacuation. As a result, it has been found that it is not easy to achieve both of enhancement fire-proofing and smoke-proofing performance of the refugee path (enhancing heat isolation and smoke blocking performance) for the fire screen formed with the slit and easiness to pass through the slit. Namely, when a person passes through the silted refugee path, the person widens the slit by hand and body to pass through. If the widened gap is remained even after the person past through the slit, the remained relatively wide gap should degrade fire-proofing and smoke-proofing performance significantly. On the other hand, when measure is taken to quickly restore the original screen state quickly after the person passes through the slit, it can serve to interfere passing through of the people. The present invention has been worked out in view point of the finding set forth above and based on the results of various research and experiments. Therefore, it is an object of the present invention to provide a fire limiting screen arrangement with walk-through feature, which can be easy to implement with employing a flexible heat resistive and fire-proofing cloth screen at low cost, requires smaller space for storage, demonstrates relatively high fire-proofing and smoke-retarding performance in effectively closing opening in the building, and can permit people to easily pass through in the closed condition to facilitate evacuation at emergency. According to one aspect of the invention, there is provided a walk-through type fire-limiting screen arrangement comprising: a non-combustible or fire-proof screen drooping from a ceiling or a beam for isolation of an interior space of a building; at least one slit portion extending vertically down to the lower end of said screen; a predetermined width of closure flap portion associated with said at least one slit for closing said slit portion with a predetermined overlap between said at least one slit portion and said closure flap portion; a main weight bar horizontally fixed along the lower end of said screen except for said closure flap portion; a sub-weight bar horizontally fixed along the lower end of said closure flap portion; characterized in that said main weight bar is a single bar member having a bar intermediate portion located right below said closure flap portion in said screen, which bar intermediate portion is not coupled to the said closure flap portion. In one embodiment, the closure flap portion may include mutually separated a front side flap and a back side flap, the front side flap and the back side flap being formed with a plurality of slits extending vertically to the lower ends for dividing into a plurality of flap strips, respectively, and the positions of the slits formed in the front side flap being transversely shifted to the positions of the slits formed in the back side flap so as not to overlap to each other. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood more fully from the detailed description given herebelow and from the accompanying drawings of the preferred embodiment of the invention, which, however, should not be taken to be limitive to the present invention, but are for explanation and understanding only. In the drawings: Fig. 1 is a perspective view of a walk-through type fire limiting screen arrangement; Fig. 2 is a front elevation of the first embodiment of a walk-through type fire limiting screen arrangement according to the present invention; Figs. 3A and 3B are plan views of the walk-through type fire limiting screen arrangement of Fig. 2; Fig. 4 is a perspective view of a modification of the first embodiment of a walk-through type fire limiting screen arrangement according to the present invention; Figs. 5A and 5B are enlarged partial sections of the walk-through type fire limiting screen arrangement of Fig. 4; Fig. 6 is a perspective view of a walk-through type fire limiting screen arrangement not according to the present invention; Fig. 7A is a front elevation of the second embodiment of a walk-through type fire limiting screen arrangement according to the present invention; Fig. 7B is a plan view of the walk-through type fire limiting screen arrangement of Fig. 7A; Fig. 8A is a front elevation of a modification of the second embodiment of a walk-through type fire limiting screen arrangement according to the present invention; Fig. 8B is a plan view of the walk-through type fire limiting screen arrangement of Fig. 8A; Fig. 9 is a front elevation of a walk-through type fire limiting screen arrangement not according to the present invention; Fig. 10 is a plan view of the walk-through type fire limiting screen arrangement of Fig. 9; Fig. 11 is a front elevation of a walk-through type fire limiting screen arrangement according to the present invention; Fig. 12 is a plan view of the walk-through type fire limiting screen arrangement of Fig. 11; Fig. 13 is an enlarged section of the major part of the walk-through type fire limiting screen arrangement of Fig. 12; Fig. 14 is a perspective view of a walk-through type fire limiting screen arrangement not according to the present invention; Fig. 15 is an enlarged perspective view of the major part of the walk-through type fire limiting screen arrangement of Fig. 14; and Fig. 16 is an enlarged perspective view of another major part of the walk-through type fire limiting screen arrangement of Fig. 14. DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention will be discussed hereinafter in detail in terms of the preferred embodiment of the present invention with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be obvious, however, to those skilled in the art that the present invention may be practiced without these specific details. In other instance, well-known structures are not shown in detail in order to avoid unnecessarily obscure the present invention. The general construction of a walk-through type fire limiting screen arrangement not according to the present invention is shown in Fig. 1. The shown fire limiting screen arrangement is primarily constructed with a formed with a non-combustible or fire-proof screen 1, such as a glass fiber fabric, silica cloth or the like (hereinafter simply referred to as "fire-proof screen"). The fire-proof screen 1 is rolled up on a shaft 2 arranged horizontally on a ceiling or a beam. The screen droops to reach a floor surface by its own weight. On the other hand, at both sides of the fire-proof screen 1 contacts on a wall surface or a column surface to separate an opening portion in the building. At this time, in order to eliminate a gap between both side portions of the fire-proof screen 1, guide rails (not shown and will be discussed later) on the wall surface and the column surface. Within channel grooves of respective guide rails, the both side edges of the fire-proof screen are received within the channel grooves. The shaft 2 is coupled with a take-up driving device for extracting and retracting the fire-proof screen by an electric motor, The entire fire-proof screen is rolled up or retracted beneath the ceiling. At the center portion of the fire-proof screen, a slit portion 3 extending vertically and reaching the lower end is formed. By separating the fire-proof screen 1 a the slit portion 3 into left and right, a screen door portion is formed. On the other hand, in order to prevent formation of gap, the left and right screens are overlapped in an appropriate amount. An overlapping margin is preferably 30 to 50 cm. At the lower end of the fire-proof screen 1, except for the left and right portions of the predetermined length in the slit portion 3 forming the screen door portion, main weight bars 4a and 4b are fixed horizontally. In this embodiment, the main weight bar is formed as two separated bar members. The two separate bars 4a and 4b are fixed to the lower ends of the fire-proof screen in spaced apart relationship except for the lower end of the center portion. The portion where the two main weight bars 4a and 4b are not fixed, namely the portions of the predetermined length of the fire-proof screen at the slit portion 3, left and right independent sub-weight bars 5a and 5b are horizontally fixed. On the other hand, the tip ends of the left and right independent sub-weight bars 5a and 5b corresponding to overlapping margin of the fire-proof screen 1 at the slit portion 3 are overlapped in the horizontal direction. The overlapping portion R of the sub-weight bars 5a and 5b form complementary configuration. In the overlapping portion R of the bars 5a and 5b, both sub-weight bars 5a and 5b are mutually drawn by magnetic force of permanent magnets. In the free condition depending upon gravity, entire fire-proof screen 1 droops vertically. At this condition, the main weight bars 4a and 4b and the sub-weight bars 5a and 5b are placed in alignment as shown in Fig. 1. Thus, substantially no gap is formed in the slip portion 3 with the overlapping margin. By the own weight of the fire-proof screen 1 and additional amount of the weight bars 4a, 4b, 5a and 5b, the screen 1 does not easily flit by a little wind pressure or pressure difference to maintain stable condition. By this, substantially high level fire propagation preventing performance and smoke limiting performance are realized. At the emergency, person may easily pass through the slit portion 3 of the fire-proof screen 1. While the screens are overlaps at the slit portion 3, by depressing the screen cloth located at the backside of the overlap by human hand or body in the direction x of Fig. 1, overlapping portion R at the tip ends of the sub-weight bars 5a and 5b are released away from each other to form a large gap at the slip portion 3. Thus, people may easily pass across the fire-proof screen. Even from the other side, the people may easily pass across the fire-proof screen. Figs. 2, 3A and 3B show a first embodiment of the walk-through type fire limiting screen arrangement according to the present invention. In the shown embodiment, the main weight bar 40 includes a bar intermediate portions 41 located right below the portion of the predetermined lengths of the left and right portions of the slit portion 3 at the lower end of the fire-proof screen 1 and being not coupled with the foregoing predetermined lengths of left and right portions. In the normal state, the bar intermediate portions 41 are integrated together with the bar main bodies 42 and 43 to form an aligned bar. It should be noted that bar main bodies 42 and 43 form the main-weight bars 4a and 4b in the first embodiment of Fig. 1. On the other hand, the sub-weight bars 5a and 5b and the bar intermediate portion 41 are magnetically drawn to each other. It should be noted that the reference numeral 6 in Fig. 2 denote guide rails. Figs. 4, 5A and 5B are a modification of the first embodiment of the walk-through type fire limiting screen arrangement according to the present invention. The main weight bar 40 includes a bar intermediate portions 41 located right below the portion of the predetermined lengths of the left and right portions of the slit portion 3 at the lower end of the fire-proof screen 1 and being not coupled with the foregoing predetermined lengths of left and right portions. In the normal state, the bar intermediate portions 41 are integrated together with the bar main bodies 42 and 43 to form an aligned bar. In the shown modification, one of left and right sub-weight bars 5a and 5b mutually independent of each other contacts one side of the bar intermediate portion 41, and the other sub-weight bar 5b contacts with the other side of the bar intermediate portion 41. Here, the sub-weight bars 5a and 5b and the bar intermediate portions 41 are mutually drawn to each other by magnetic force of the permanent magnets. As clearly shown in Fig. 4, in order to eliminate gaps between both side portions of the fire-proof screen 1, the guide rails 6 are provided vertically on the wall surface and the column surface so that the both side edge portions of the screen are received within the channel grooves of the guide rails 6. It should be noted that, in the shown embodiment, the biparting construction has been discussed, the present invention is, of course, applicable for single swing construction. Fig. 6 shows a further embodiment applied for the single swing type screen arrangement. In the shown embodiment, the sub-weight bar is constructed with only bar 8a. Figs. 7A and 7B show the second embodiment of the walk-through type fire-limiting screen arrangement according to the present invention. The screen 1 has a screen main body portion 1b which is formed with an opening portion 1a for the refugee path, at the predetermined position. The opening portion 1a of the screen main body portion 1b reaches the lower end. The screen 1 also includes a closure flap portion 1c which is arranged for closing the opening portion 1a and integrated with the screen main body portion 1b at the upper portion. In the shown embodiment, the width of the opening portion 1a becomes smaller at lower portion. Both side portions of the closure flap portion 1c has the uniform width. Thus, the width of the overlapping portion of the closure flap portion 1c with the screen main body portion 1b is greater at the lower portion. Smaller overlapping portion may reduce interference upon passing through. On the other hand, the main weight bar 40 is horizontally arranged over the substantially entire width of the lower end of the screen 1. The main weight bar 40 is fixed to the lower end of the screen main body portion 1b but is separated from the closure flap portion 1c closing the opening portion 1a. On the lower end of the closure flap portion 1c, a sub-weight bar 8 is fixed horizontally. In the main weight bar 40, the portion located right below the closure flap portion 1c is cut-out at the upper portion and is formed to be thinner for fixing to the screen main body portion 1b. The thinner portion of the main weight bar 40 is located in substantially parallel in contact with the sub-weight bar 8 on the central cut-out portion. The sub weight bar 8 is constrained from movement relative to the main weight bar 40 in dynamically loose manner so that it may displace in significant amount relative to the main weight bar as exerted the external force when the person passes through the opening. Unless the external force is exerted, the constraining force of the coupling means returns the predetermined arrangement position with substantially contacting with the main weight bar 40. Figs. 8A and 8B show modification of the second embodiment. In the shown embodiment, the refugee path by the closure flap portion 1c forms one-way path. Namely, in mechanical combination, the main weight bar 40 and the sub-weight bar 8, the sub-weight bar 8 is located at the front side of the main weight bar 40 for facilitating passing a person through from the back side of the screen 1 to the front side. Against force exerted in the opposite direction, i.e. from front side to the back side, the sub-weight bar 8 abuts on the main weight bar to prevent the closure flap portion 1c from being opened. By making the refugee path as one-way path, fire propagation prevention and smoke blocking performance can be enhanced. As can be seen, in the shown embodiment, the closure flap portion 1c is provided in front of the screen main body portion 1b and has overlapping portions having greater and uniform width. Such greater overlapping portion should contribute for enhancement of propagation prevention and smoke blocking performance while easiness of passing through is not sacrificed for permitting only one-way opening of the closure flap portion 1c. Figs. 9 and 10 show a walk-though type fire-limiting screen arrangement not according to the present invention. In the shown embodiment, the closure flap portion 1c for closing the opening portion 1a of the screen main body portion 1b is provided at the center portion. In the shown embodiment, the closure flap portion 1c is formed with a front side flap and a back side flap overlapping with each other. Respective of the front side flap and the back side flap are formed with a plurality of slits Sa and Sb, respectively extending vertically from the lower ends of the flaps and thus divided into a plurality of flap strips. Hereinafter, the flap strips of the front side flap will be referred to as front side flap strips 7a and the flap strips of the back side flap will be referred to as rear side flap strips 7b. On the lower ends of the front side flap strips 7a of the closure flap portion 1c, respectively independent short sub-weights 8a arefixed horizontally. Similarly, on the lower ends of the rear side flap strips 7b, respectively independent short sub-weights 8b are fixed horizontally. Also, on the lower end of the right side portion of the screen main body 1b, a right side main weight bar 4a is fixed horizontally. Similarly, on the lower end of the left side portion of the screen main body 1b, a left side main weight bar 4b is fixed horizontally. In the condition where the whole screen is drooping by its own weight, respective sub-weight bars 8a are aligned and respective sub-weight bars 8b are aligned. Two strings of the sub-weight bars 8a and 8b are arranged in parallel in contact with each other. Two strings of the sub-weight bars 8a and 8b are wholly in alignment with the left and right main weight bars 4a and 4b/ At this condition, the screen is in vertically drooping condition. On the lower end portion of the sub-weight bars 8a and 8b, through openings extending horizontally are formed. Through openings which are to be aligned with the through openings of the sub-weight bars 8a and 8b, are formed in the left and right main weight bars 4a and 4b. Through a series of through holes of respective sub-weight bars 8a (8b), a single wire 9a (9b) is inserted. Both ends of the wire 9a (9b) are inserted into the through openings 4a and 4b of the main weight bars 4a and 4b. Within the holes of the main weight bars 4a and 4b, coil spring 10a (10b) are connected at both ends of the wire 9a (9b). The other end of the coil spring 10a (10b) is fixed to the main weight bar 4a (4b). The wire 9a (9b) and two coil springs 10a (10b) at both ends are resilient expansion member of the primary element of the coupling member. In the construction set forth above, the entire screen droops by the weights of the main weight bars 4a and 4b and the sub-weight bars 8a and 8b to be placed in substantially stable condition. In addition to this, by means of the wires 9a and 9b and the coil springs 10a and 10b, respective sub-weight bars 8a and 8b and the main weight bars 4a and 4b are coupled in alignment and dynamically loosely constrained. Namely, since the wires 9a (9b) extend through the through openings of respective sub-weight bars 8a (8b) and the main weight bars 4a and 4b and applied an appropriate tension by the resilient force of the coil spring 10a (10b), respective sub-weight bars 8a (8b) and the main weight bars 4a and 4b are aligned in-line. At this condition, little gap may be formed in the closure flap portion 1c. Also, the flap strips should not flit even with slight wind pressure or pressure difference to maintain stable attitude. Thus, substantially high level fire propagation preventing performance and smoke blocking performance can be realized. On the other hand, when a person passes through the closure strap portion 1c. he may insert the hand or body through the slits Sa and Sb to flaring the flap strips 7a and 7b. This external force is transmitted to the flap strips 7a and 7b and the sub-weight bars 8a and 8b to the wires 9a and 9b to expand the coil springs 10a and 10b. Namely, the wires 9a and 9b are expanded at the portion of the flap strips 7a and 7b flared by the refugee to cause displacement on specific sub-weight bars 8a and 8b from the normal position to widen the slits Sa and Sb to permit the refugee to pass therethrough. Once the refugee passes through, due to own weights and the spring force of the coil springs 10a and 10b, respective sub-weight bars 8a and 8b and the main weight bars 4a and 4b are quickly aligned and returned to the normal position. Thus, the flap strips 7a and 7b are returned to the normal position to achieve high fire propagation preventing performance and smoke blocking performance. Figs. 11, 12 and 13 show the third embodiment of the walk-through type fire limiting screen arrangement according to the present invention. The main weight bar 40 in the shown embodiment is fixed to the lower end of the screen main body portion 1b. However, the main weight bar 40 is not fixed to the front side flap strips 7a and the back side flap strips 7b which, in combination, form the closure flap portion 1c. Independently of the main weight bar 40, mutually independent short sub-weight bars 8a are horizontally fixed on the lower ends of the front side flap strips 7a. Similarly, mutually independent short sub-weight bars 8b are horizontally fixed on the lower ends of the back side flap strips 7b. The portion of the main weight bar 40 lying a position right below the closure strip portion 1c, is cut-out the upper portion to be thinner than the portions fixed to the screen main body portion 1b. On the central cut-out portion of the main weight bar 40, a series of sub-weight bars 8a and a series of sub-weight bars 8b respectively arranged in alignment are received in parallel relationship to each other. Through the sub-weight bars 8a and 8b, through openings extending horizontally are formed. Through openings which are to be aligned with the through openings of the sub-weight bars 8a and 8b, are formed in the main weight bars 40. Through a series of through holes of respective sub-weight bars 8a (8b), a single wire 9a (9b) is inserted. Both ends of the wire 9a (9b) are inserted into the through opening of the main weight bar 40, Within the holes of the main weight bar 40, coil spring 10a (10b) are connected at both ends of the wire 9a (9b). The other end of the coil spring 10a (10b) is fixed to the main weight bar 40. The wire 9a (9b) and two coil springs 10a (10b) at both ends are resilient expansion member of the primary element of the coupling member. In the main weight bar 40, hook-shaped stopper holes 11a (11b) are formed at the positions located between adjacent sub-weight bars 8a and 8b. The wire 9a between the sub-weight bars 8a and 8a is inserted through the stopper holes 11a, and the wire 9b between the sub-weight bars 8b and 8b is inserted through the stopper holes 11b. The sub-weight bars 8a and 8b are moved significantly in response to application of external force manually exerted by refugee upon passing therethrough, with causing associated displacement of the flap strips 7a and 7b for permitting the refugee to pass therethrough. Upon removal of the external force after passing through of the refugee, respective sub-weight bars 8a and 8b are moved to the normal position to close the closure flap portion 1c. Figs. 14, 15 and 16 show a walk-through type fire-limiting screen arrangement not according to the present invention, In the shown embodiment, the fire-limiting screen is formed with four smaller width screens 1A, 1B, 1C and 1D arranged in horizontal alignment. This type of arrangement is particularly suitable for separating relatively large space in the building. In the practical embodiment, respective smaller width screens 1A to 1D may have a width of about 8m and a height of about 5m. Side edge portions of respective smaller width screens may overlap with each other in the extent of 50 cm. Each smaller width screen 1A to 1D droops from a take-up device 20 housed within a storage box B arranged on the ceiling portion of the building. As shown in Fig. 15, independent take-up devices 20 are provided for each of the smaller width screens 1A to 1D for taking-up each individual screen independently of the other. A length of each of take-up shafts is about 8m substantially corresponding to the width of the smaller width screens 1A to 1D. Thus, in the shown embodiment, four take-up devices 20 are provided. Adjacent take-up devices 20 are arranged offsetting toward left and right sides relative to a drooping plane, along which the smaller width screens 1A to 1D droop. Since the take-up devices 20 are alternately arranged at either sides of the drooping plane, the take-up directions of the screens are alternated depending on the side to be placed so that the all of the four smaller width screens 1A to 1D may droop along the same drooping plane. With this arrangement, even when the smaller width screens are arranged with overlapping the side edges, the take-up devices 20 for adjacent screens will never cause interference to each other. Furthermore, the smaller width screens 1A to 1D may droop substantially vertically on substantially the same plane. The take-up shaft of each take-up device may be driven by an electric motor or the like for extracting and retracting the screens. As taken up or retracted, the smaller width screens 1A to 1D are housed within the storage box B, and, as extracted, the screens 1A to 1D droop down to separate the interior space of the building. Of course, each of four individual take-up devices 20 can be controlled independently. Therefore, four smaller width screens 1A to 1D may be extracted and retracted independent of the other. As shown in Fig. 16, on the lower ends of respective of the smaller width screens 1A to 1D, respectively independent weight bars 8 are horizontally fixed. By the weight of the weight bar 8, an appropriate tension force can be exerted on each of the smaller width screens so that the screens as combined may form smooth plane and may not flit by wind or the like. Furthermore, as shown in Fig. 16, at the overlapping portion between adjacent smaller width screens, e.g. 1A and 1B, the weight bar 8 of the smaller width screen 1A is partly cut-out at the front side (hereinafter referred to as cut-out portion a). On the other hand, the weight bar 8 of the smaller width screen 1B is partly cut-out at the back side (hereinafter referred to as cut-out portion b). The cut-out portions a and b are complementary so that they may form a single bar as combined. With such arrangement, the screens 1A and 1B may be placed in tightly contacting state. Of course, the same is true for all of other overlapping portions. On the other hand, as shown in Fig. 14, the smaller width screen 1D is formed with a plurality of slits S extending vertically from the intermediate position between the upper and lower ends of the screen. The portion of the screen 1D where the slits S are formed may define the refugee path, through which the refugee may easily pass. Since the smaller width screens are formed with flexible cloth, the people may easily pass through the refugee path by flaring the flap strips separated by the slits set forth above. The clearance resulting from flaring is the flap strips permits to pass the refugee. Namely, when the fire-limiting screen is formed by the smaller width screen 1A to 1D, the portion where a plurality of slits are formed, may serve as refugee path which corresponds to the fire retarding door. The position of the refugee paths may be set depending upon the setting condition of the of the refugee path, use condition of the interior space or other factors. As set forth above, according to the present invention, relatively large space can be separated by arranging a series of smaller width screens for defining the fire-limit or smoke limit. Since respective screens may be extracted and retracted and opened and closed, even when one of the refugees is stamped by the weight bar at the occurrence of fire, he may repulse the weight bar. On the other hand, even when one or more people are fail to escape, they may pass therethrough by lifting the weight bar. Furthermore, since the smaller width screens may be combined to form the partition with the fire-resistance, each individual screen may be taken up or drooped down independently, quite high practical use can be achieved. Also, the take-up device for each screen can be operated independently of the other can be made small. The take-up device thus can be fabricated at low cost and easily. Furthermore, the weight bars provided on the lower ends of respective smaller width screens may be combined like a single bar so that the screens as drooped down may permit tight contact. Thus, isolation performance, fire-proofing limit performance, smoke limit performance or the like may not be degraded. Although the invention has been illustrated and described with respect to exemplary embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without departing from the scope of the present invention. Therefore, the present invention should not be understood as limited to the specific embodiment set out above but to include all possible embodiments which can be embodies within a scope encompassed and equivalents thereof with respect to the feature set out in the appended claims.

Claims: A walk-through type fire-limiting screen arrangement comprising: a non-combustible or fire-proof screen (1) drooping from a ceiling or a beam for isolation of an interior space of a building; at least one slit portion (3) extending vertically down to the lower end of said screen; a predetermined width of closure flap portion associated with said at least one slit for closing said slit portion with a predetermined overlap between said at least one slit portion and said closure flap portion; a main weight bar (40) horizontally fixed along the lower end of said screen except for said closure flap portion; a sub-weight bar (5a,5b) horizontally fixed along the lower end of said closure flap portion; characterized in that said main weight bar (40) is a single bar member (42, 43) having a bar intermediate portion (41) located right below said closure flap portion in said screen, which bar intermediate portion is not coupled to the said closure flap portion. A walk-through type fire-limiting screen arrangement as set forth in claim 1, wherein said closure flap portion includes mutually separated a front side flap and a back side flap, said front side flap and said back side flap being formed with a plurality of slits extending vertically to the lower ends for dividing into a plurality of flap strips, respectively, and the positions of said slits formed in said front side flap being transversely shifted to the positions of said slits formed in said back side flap so as not to overlap to each other. A walk-through type fire-limiting screen arrangement set forth in claim 2, wherein each of sub-weight bars (5a,5b) fixed to the lower ends of said flap strips of said front side flap are connected to said main weight bar by a resilient expandable member to be arranged substantially in alignment, and each of sub-weight bars fixed to the lower ends of said flap strips of said back side flap are connected to said main weight bar (40) by a resilient expandable member to be arranged substantially in alignment. A walk-through type fire-limiting screen arrangement as set forth in claim 1, wherein said sub-weight member (5a,5b) is constrained with respect to said main weight bar (40) by a coupling means in dynamically loose manner for permitting movement relative to said main weight bar in response to an external force for permitting a person to pass through, and otherwise, being arranged substantially in alignment with said main weight bar to return an initial position. A walk-through type fire-limiting screen arrangement as set forth in claim 4, wherein said coupling means comprises a combination of a permanent magnet and a magnetic body for magnetically establishing engagement between said main weight bar (40) and said sub-weight bars (5a,5b). A walk-through type fire-limiting screen arrangement as set forth in claim 4, wherein said coupling means is constructed by connecting said main weight bar and said sub-magnetic bars by means of resiliently expandable member. A walk-through type fire-limiting screen arrangement as set forth in claim 4, wherein an overlapping portion between each side of said closure flap portion and said screen main body is gradually increased toward the lower end of the screen.

Inventors: HONMA MASAHIKO, MIYAGAWA YASUYUKI, MIYAKE AKIRA, MURAOKA KOU, HONMA, MASAHIKO, MIYAGAWA, YASUYUKI, MIYAKE, AKIRA, MURAOKA, KOU
Applicants: OHBAYASHI CORP, OBAYASHI CORPORATION
Application year: 1997
Main classification: A62C2
IPC codes: A62C2