DOOR MACHINE OF FIREPROOF DOOR

Abstract

A door machine of a fireproof door comprises an input end to be actuated by an input axle; an output end loaded with weight of door panels, the loading force of which is transmitted back to a central axle through an output axle; a clutch mechanism normally connecting the central axle with the input axle together; a brake mechanism including a torsion spring which is integrated with the input axle of the input end and one end of which bears the loading force came from the central axle to shrink the inner diameter thereof so that the input axle is in an immobilized state; when an external force is applied to the input end, the other end of the torsion spring resisting against the weight of the door panels to expand the inner diameter thereof so that the input axle is rotated.

Description

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to a door machine of a rolling door, more particularly to a door machine of a fireproof door which can be shut by rolling-down of door panels due to its own weight in the event of a fire accident.

2. Brief Description of the Prior Art

General door machine used in a fireproof rolling door comprises either a failsafe type or a non-failsafe type door machine according to the type of operation. In power interruption condition, the failsafe type door machine is releases a brake so as to close the fireproof door at once regardless of the cause of power interruption. In other words, even in the case that the power is not interrupted in the event of a fire accident, the power source can be cut off to release the brake by a fire fighting control device such as a smoke detector, a temperature sensor or the other fire monitoring device so that the door panels are rolled down due to their own weight to close the door. The main feature of this type lies in that the door can be immediately closed in an event of a fire incident so as to block the fire and the dense smoke from spreading if the power interruption is certainly caused by fire.

In contrast to the above, the non-failsafe type door machine in power interruption condition still keep the brake in an activated state regardless of the cause of power interruption so that the fireproof door is not shut immediately. Only in the case that the fusible link is molten by a high temperature caused by a fire, the mechanical type brake is actuated mechanically so that the door panels s fall downward due to their own weight to close the door. The main feature of this type lies in that personnel entering/leaving through the fireproof door is not interrupted if the power interruption is caused by non-fire factors.

So far, several documents concerning the failsafe type door machine of fireproof door have been proposed, for example, in U.S. Pat. No. 5,673,514 and U.S. Pat. No. 5,893,234. Basically, two electromagnets are used to maintain a brake device in a braking state under power-on condition, or to release the brake so as to close the door at once in the power interruption state. The structure of this failsafe door machine of fireproof door is very complicated and has a huge volume. On the other hand, documents concerning the non-failsafe door machine of fireproof door such as U.S. Pat. No. 5,203,392 and U.S. Pat. No. 5,386,891 are known to the public, in which either the manual operation of the door machine should be done through mode-switching or a chain is pulled to move a chain disc and at the same time the brake should be released to rotate a rotary axle. Hence, improvement to use and structure of the conventional art is expected.

SUMMARY OF THE INVENTION

The main object of the present invention is to provide a simplified door machine of a fireproof rolling door by which a reel of the rolling door can be released to close the door in the event of a fire accident. Hence, the disadvantages of complicated structure, huge volume and inconvenient operation occurred in prior art can be improved.

In order to achieve above objects, the door machine of fireproof door according to this invention comprises: a housing enclosing an accommodation space and having an output axle pivotally disposed at a first set position of the housing, the output axle having an output wheel fixed at the left end thereof for rotating a reel of door panels; an input axle pivotally disposed at a second set position of the housing and rotated by an external force; a central axle pivotally disposed at a third set position of the housing, the left end of the central axle being linked with the output axle and the right end thereof being fixed with an end disc; a sliding sleeve which is loosely fitted on the central axle between both ends of the central axle and slidable between a first set point and a second set point on the central axle, a rotatable first gear disc being fixed at the right end of the sliding sleeve and engaged with a second gear disc fixed on the input axle; a clutch mechanism which is arranged around the outer periphery of the left end of the sliding sleeve and holds the sliding sleeve at the second set point under control so that the end disc and the first gear disc are connected with each other; a brake mechanism having a first bushing loosely fitted on the left end of the input axle and fixed on the housing; a torsion spring arranged to encircle the outer periphery of the first bushing, one end of the torsion spring normally bearing the weight of the door panel so that its inner diameter is shrunk to be tightly constricted on the first bushing so as to brake the input axle; a driving mechanism comprising an input wheel fixed at the left end of the input axle for applying an external force on the other end of the torsion spring to resist against the weight of the, door panel so that the inner diameter of the torsion spring is enlarged and the input axle is rotated.

In this manner, when no external force is applied on the driving mechanism, the weight of the door panels is applied on the output wheel and simultaneously the input axle tends to twist the torsion spring so as to keep a brake in braking state; and when a fire accident happens, the clutch mechanism return the sliding sleeve to the first set point under control so that the end disc is disengaged from the first gear disc. Thus, the door panels can fall down due to their own weight to shut the door so as to block fire or the dense smoke from spreading in the event of fire accident.

According to the present invention, both ends of the torsion spring are free ends and formed with convex protrusions respectively. Each protrusion has a twisted direction side and a de-twisted direction side. The driving force applied from the input end is applied indirectly on the de-twisted direction side of the torsion spring so that the inner diameter of the torsion spring can be enlarged to rotate the input axle. Alternatively, the weight of the door panels of the output end is applied indirectly on the twisted direction side of the torsion spring so that the inner diameter of the torsion spring is shrunk so as to brake the input axle. Activation and deactivation of the brake device upon operation or non-operation of the door machine is automatically realized by the torsion spring without an additional switching element. Therefore, the operation is convenient and probability of false is reduced. This is another object of the present invention.

According to the present invention, the mechanisms for the structure of the door machine are modulized and are arranged one above another. Further, by using the clutch mechanism with an inner axle being fitted into an outer axle, the structure of the door machine can be simplified and made compact. This is still another object of the present invention.

According to the present invention, the door machine can be configured as a failsafe type door machine of fireproof door by introduction of an electromagnetic clutch or configured as a non-failsafe type door machine of fireproof door by introduction of a mechanical clutch. The door machines of the two types are nearly made of the same common parts. Not only development cost is low but also the number of parts is less. The production is simplified, parts in stock is reduced and assembly is easy. This is still another object of the present invention.

According to the present invention, an exciting circuit for clutch is used to maintain power for the electromagnetic clutch under normal power supply condition. This circuit includes a delay circuit formed by a plurality of capacitors which charged in the normal state. The electromagnetic clutch can be energized and temporarily excited by the capacitors immediately after the abnormal power interruption caused by the fire accident so that the timing for shutting the door can be delayed for personnel evacuation. This is yet another object of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The technical features of the present invention will become more apparent by the descriptions of the following embodiments in conjunction with accompanying drawings. However, it is noted that the embodiments are only preferred embodiments of the present invention, not intended to limit the scope of the present invention. Further, the direction, the terms “left” and “right” shown in the context is for the convenience of description but not for restrictive purpose.

Firstly, a first embodiment of the failsafe type door machine of fireproof door of the present invention is described by referring to FIG. 1 and FIGS. 1a to 1h. As shown in FIG. 1, the door machine 1 of the present invention comprises:

a housing 10 enclosing an accommodation space and having an output axle 11 pivotally disposed at a first set position of the housing 10, the output axle 11 having an output wheel 111 fixed at the left end thereof for rotating a reel (not shown) of the door panels; an input axle 17 pivotally disposed at a second set position of the housing 10, the input axle 17 being rotated by applying an external force to an input wheel 281 fixed to the left end of the input axle 17;

a central axle 13 pivotally disposed at a third set position of the housing 10, the left end of the central axle 13 having a conventional transmission means such as gears fixed to the left end of the central axle 13 so as to be linked with the output axle 11, and an end disc 15 fixed to the right end thereof, a brake lining 150 being provided on the left end face of the end disc 15;

a sliding sleeve 14 loosely which is fitted on the central axle 13 between both ends of the central axle 13 and slidable axially on the central axle 13; wherein a first gear disc 141 is arranged at the right end of the sliding sleeve 14 in such a manner that the first gear disc 141 is rotatable with respect to the sliding sleeve 14 and is engaged with a second gear disc 171 fixed on the input axle 17, so that the first gear disc 141 can slide axially together with the sliding sleeve 14 and be rotated with respect to the sliding sleeve 14;

an electromagnetic clutch mechanism 23 arranged to encircle the outer periphery of the sliding sleeve 14 at the left end and fixed on a partition plate 101 of the housing 10, the electromagnetic clutch mechanism 23 generating an electromagnetic force to move the sliding sleeve 14 to the right, so that the end disc 15 is kept connected with the first gear disc 141 through the brake lining 150;

a brake mechanism 27 having a first bushing 271 loosely fitted on the left end portion of the input axle 17 and fixed to the housing 10; a torsion spring 272 arranged to encircle the outer periphery of the first bushing 271, one end of the torsion spring 272 normally bearing the weight of the door panels so that its inner diameter tends to shrink so as to be constricted tightly on the first bushing 271 and to make the input axle 17 unrotatable;

a driving mechanism 28, when an external force is applied through the input wheel 281 arranged at the left side, the left end of the torsion spring 272 being capable of resisting against the tendency of shrinking the inner diameter of the torsion spring 272 by the weight of the door panels so that the inner diameter of the torsion spring 272 is enlarged and the external force can be acted to rotate the input axle 17.

As will be described later, the brake mechanism 27 and the driving mechanism 28 can be integrated into a compact structure (as shown in. FIG. 1c).

As shown in FIG. 1, the present invention further comprises a conventional reduction mechanism 21, formed by a plurality of gears, which is located between the central axle 13 and the output axle 11. The rotation speed of the central axle 13 is reduced by the gears of the reduction mechanism 21 and transmitted to the output axle 11; and a bushing 151 extending from the right end face of the end disc 15 coaxially with the central axle 13; a conventional centrifugal type brake mechanism 25 arranged to encircle the outer periphery of the bushing 151 and fixed with the bushing 151 thereof. When the rotation speed of the central axle 13 exceeds a predetermined value, a frictional force is generated on a brake drum 152, fixed on the housing 10, by centrifugal force produced by the centrifugal type brake mechanism 25 so as to retard the rotation speed of the central axle 13.

Further referring to FIGS. 1a and 1b, the electromagnetic clutch mechanism 23 of the present invention comprises an electromagnet 231. A hollow accommodation portion 232 is enclosed with the interior of the electromagnet 231 and the left side end face of the partition plate 101. A second bushing 102 extending axially and encircling the sliding sleeve 14 is s formed on the right side end face of the partition plate 101. The left end of the sliding sleeve 14 extends into the accommodation portion 232 through the partition plate 101. An active disc 233 is provided at the left side of the electromagnet 231, which has an end face facing the electromagnet 231. A passive disc 234 is loosely fitted on the second bushing 102. The left end face of the passive disc 234 is abutted against the right end face of the partition plate 101, and a bushing 234a extending coaxially with the second bushing 102 in the direction toward the first gear disc 141 is formed on the right end face of the passive disc 234. On the bushing 234a, a thrust bearing 235 and a reset spring 236 are provided in order between the passive disc 234 and the first gear disc 141. A plurality of screws 237 pass through the hollow accommodation portion 232 within the electromagnet 231 and the partition plate 101 from the active disc 233 and are connected integrally with the passive disc 234. An elastic element 143 is installed at the left end of the sliding sleeve 14, the elastic restoring force of the elastic element 143 urges the sliding sleeve 14 to slide to the left side. And in case of power failure, the first gear disc 141 connected with the sliding sleeve 14 slides to the left side together with the sliding sleeve 14 so as to be disengaged from the end disc 15, as shown in FIG. 1b. In normal power supply condition, an exciting circuit for clutch shown in FIG. 1b is used to maintain the electromagnet 231 in an excited state, and the active disc 233 is attracted by the electromagnet 231 and thus moved to the right. In this manner, the passive disc 234, which is fastened together with the active disc 233 by the screws 237, is abutted against the left end face of the first gear disc 141. At this moment, the sliding sleeve 14 arranged in such a manner that the sliding sleeve 14 is rotatable with respect to the first gear disc 14 resists against the elastic force of the elastic element 143 and thus is also moved to the right, so that the first gear disc 141 is abutted against the end disc 15 and is in frictional contact with the latter.

Further referring to FIGS. 1c to 1f, the brake mechanism 27 and the drive mechanism 28 are integrated together by the torsion spring 272. The torsion spring 272 has an inner diameter which is tightly constricted on the left end portion of the first bushing 271. As shown in FIGS. 1e and 1f, both ends of the torsion spring 272 are free ends which have protrusions 2721 respectively projecting radially outward and staggering with each other by 90 degrees. As shown in FIG. 1e, an inner race portion 273 and an outer race portion 274 are fitted with each other and arranged at the left side of the second bushing 271. The outer race portion 274 is fixed on the input wheel 281 so that the inner race portion 273 and the outer race portion 274 can be rotated with respect to each other. On the right end face of the inner race portion 273, a pair of axial baffle plates 2731 arranged opposite to each other in radial direction are provided at places beyond the outer diameter of the torsion spring 272. Similarly, on the right end face of the outer race portion 274, a pair of axial pushing plates 2741 arranged opposite to each other in radial direction are provided at places on the same inner diameter as the baffle plate 2731. The pair of baffle plates 2731 and the pair of pushing plates 2741 encircle the periphery of the torsion spring 272, and gaps are formed respectively between the baffle plates 2731 and the pushing plate 2741 adjacent to each other for receiving respectively the two protrusions 2721 of the torsion spring 272. According to the present embodiment, the input wheel 281 is a chain disc 281′ with a chain (not shown) wound on the periphery of the chain disc 281′.

Referring to FIG. 1h, FIGS. 1a and 1b, the operation of the door machine by using the torsion spring 272 of the door machine of the present invention will be described. In normal power supply condition, the exciting coil R1 reduces an electromagnetic force on the electromagnet 231 of the clutch mechanism 23 so as to attract and move the active disc 233 to the right side. Thus, the screws 237 fixed on the active disc 233 push and move the passive disc 234 together with the sliding sleeve 14 to the right side so that the first gear disc 141 is abutted against the end disc 15 and in a frictional contact with the latter. Therefore, the rotation of the input axle 17 can be transferred to the central axle 13 through the first gear disc 141 so as to maintain the linking up relation normally.

As shown in FIG. 1d, when the chain disc 281′ of the driving mechanism 28 is pulled by a chain and thus rotated in the direction of black arrow 2471, the de-twisting side b of the protrusion 2721 of the torsion spring 272 is urged by the side edge of the pushing plate 2741 and the inner diameter of the torsion spring 272 is gradually enlarged so that the torsion spring 272, which is tightly fitted on the first bushing 271, is released. Thus, with the outside force applied continuously on the chain, the torsion spring 272 is forced and rotated along the outer periphery of the first bushing 271 so that the twisting side a of the torsion spring 272 will push and rotate the baffle plate 2731 on the other side of the protrusion 2721. Simultaneously, the input axle 17 fixed together with the baffle plate 2731 is also rotated and the rotation is transferred through the second gear disc 171 fixed on the input axle 17, the first gear disc 141 engaged with the second gear disc 171, the end disc 15 in frictional contact with the first gear disc 141 to the central axle 13 fixed with the end disc 15, so that the central axle 13 drives the door panel through the output axle 11 so as to open or shut the fireproof door. On the other hand, when no force is applied on the driving mechanism 28, the weight of the door panels acts on the output wheel 111 and is transferred back through the output axle 11 and the central axle 13 to the input axle 17. At this moment, as shown in FIG. 1d, the baffle plate 2731 on the inner race portion 273 fixed together with the input axle 17 is urged and rotated and acts on the twisting side a of the protrusion 2721 of the torsion spring 272, when it is rotated in the direction of white arrows 2472. The more the door panels are rolled out, the greater the torsion force on the twisting side a is. Therefore, the inner diameter of the torsion spring 272 becomes smaller and the force on the first bushing 271 becomes bigger so as to produce a braking state.

In an event of abnormal power interruption, the clutch mechanism 28 is demagnetized so that the central axle 13 and the input axle 17 are disconnected and the door panels are smoothly rolled down to shut the door due to its own weight. Even if the power supply is not interrupted in the fire accident, the power supply can be cut off by a conventional sensor device such as a smoke as detector, a temperature sensor or another fire detector device. According to the present invention, the circuit further comprises a delay circuit C1 formed by a plurality of capacitors which are charged in normal state. The exciting coil R1 of the electromagnet 231 can be energized and temporarily excited for, for example, 10 seconds by the capacitors immediately after the abnormal power interruption caused by the fire accident so that the timing for shutting the door can be delay for personnel evacuation.

FIGS. 2 and 2 a show the second embodiment of the failsafe type door machine of fireproof door of the present invention. The basic configuration of this embodiment is similar to that of the above embodiment, so the description thereof is omitted. However, the reference numbers of elements different from that of the first embodiment are underlined. The difference of this embodiment with the first embodiment lies in that the arrange sequence of the brake mechanism 27 and the driving mechanism 28 integrated together in this embodiment is inverse to that of the first embodiment, and hence the brake mechanism 27 is arranged at the left end portion of the input axle 17 from the driving mechanism 28. In the second embodiment, the input wheel 281 is a bevel gear 281″ and a capstan device 282 is engaged with the bevel gear 281″. The capstan device 282 is actuated by a handle 283 to apply a force to the torsion spring 272 so that the inner diameter of the torsion spring 272 is enlarged and the input axle 17 is rotated.

Further, FIGS. 3, 3a and 3b show a non-failsafe type door machine of fireproof door of the third embodiment of the present invention. The basic structure of this embodiment is similar to that of the first embodiment of the failsafe type door machine of fireproof door. In this embodiment, the reference numbers of elements different from that of the first embodiment are underlined for distinction. In this embodiment, a mechanical type clutch substituted for the clutch mechanism 23 of the first embodiment comprises an accommodation portion 103 enclosed by the housing 10 and a partition plate 101, and the partition plate 101 is provided with second bushing 102 along the central axle 13 in the direction opposite to the accommodation portion 103. The sliding sleeve 14 is interposed between the second bushing 102 and the central axle 13, and the left end of the sliding sleeve 14 has a pair of limit rings 241 fitted thereon. The first gear disc 141 is rotatably fixed at the right end portion of the sliding sleeve 14 so as to slide together therewith. A thrust bearing 235 is installed in the second bushing 102, one end of the thrust bearing 235 is abutted against the end face of the partition plate 101, an elastic element 143 being provided between the other end of the thrust bearing 235 and the first gear disc 141 in such a manner that the sliding sleeve 14 tends to slide to right side so as to urge the end disc 15 and the first gear disc 141 to be in frictional contact with each other (as shown in FIG. 3a). An actuation plate 242 is fitted on the left end portion of the sliding sleeve 14. A hill shape convex face 242a projects from the end face of the actuation plate 242 and is positioned between the pair of the limit rings 241. A shift lever 243 has one end connected to a predetermined position of the actuation plate 242 and the other end extending out of the housing 10. A guiding element 26 is fixed on a frame outside the housing 10. A sliding element 261 is slidably provided within the guiding element 26, the left end of the sliding element 261 is biased toward the left side by a compressed elastic element 262, and the right end of the sliding element 261 is connected to a fusible link 263. As such, when ambient temperature exceeds the fusing point temperature of the fusible link 263 to cause melt-down of the fusible link 263, the elastic element 262 is released and urges the sliding element 261 to the left side and hit the shift lever 243 so that the sleeve 14 slides to the left side and the end disc 15 is disengaged from the first gear disc 141, as shown in FIG. 3b.

FIG. 4 shows a non-failsafe type door machine of fireproof door of the fourth embodiment of the present invention. The basic structure of this embodiment is similar to that of the first embodiment of the non-failsafe type door machine of fireproof door In this embodiment, the reference numbers of elements different from that of the first embodiment are underlined. A bevel gear 281″ in this embodiment is substituted for the input wheel 281 of the first embodiment. The driving mechanism 28 further comprises a capstan device 282 linked with the bevel gear 281″ (as shown in FIG. 2a), and the capstan device 282 is actuated by a handle 283 so as to apply a force in the de-twisting side of the torsion spring, so that the inner diameter of the torsion spring is enlarged and the input axle is rotated.

Based on foregoing, the door machine of this invention can be configured as a non-failsafe type door machine of fireproof door by introduction of a mechanical type clutch. Since most of components of the non-failsafe type door machine can be used in the abovementioned failsafe type door machine of fireproof door. Not only development cost is low but also the number of parts is less. The production is simplified, parts in stock is reduced and assembly is easy. Moreover, as the axles are arranged one above another and the inner axle in fitted within an outer axle, the structure of the door machine can be simplified and made compact. Further, activation and deactivation of the brake device upon operation or non-operation of the door machine is automatically realized by the torsion spring; hence the fireproof door can be shut in the event of fire so s as to ensure the safety.

While the present invention has been described and illustrated by the above embodiments and the accompanying drawings, it is to be understood that the scope of this invention is not limited to these embodiments. Various variations w and modifications can be made without departing from the spirit and the scope of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view showing a first embodiment of the failsafe type door machine of fireproof door of the present invention.

FIG. 1 a is a partially enlarged view of the encircled portion of FIG. 1, showing that the clutch mechanism is in engaged state.

FIG. 1 b is a partially enlarged view of the encircled portion of FIG. 1, showing that the clutch mechanism is in released state.

FIG. 1 c is a partially enlarged view of the input end of the door machine shown in FIG. 1.

FIG. 1 d is a schematic sectional view seen from the direction of line 1d-1d in FIG. 1c.

FIG. 1 e is an exploded perspective view showing the brake mechanism s and the driving mechanism of the present invention.

FIG. 1 f is an enlarged exploded perspective view showing the brake mechanism and the driving mechanism in FIG. 1e of the present invention seen from another direction.

FIG. 1 g is a perspective view showing the assembled state of the brake mechanism and the driving mechanism in FIG. 1e, in which it is sections in 90 degree.

FIG. 1 h is a schematic view showing the circuit utilized in the failsafe type door machine of fireproof door of the present invention.

FIG. 2 is a schematic sectional view showing a second embodiment of the failsafe type door machine of fireproof door of the present invention.

FIG. 2 a is a partial perspective view showing the driving mechanism of FIG. 2.

FIG. 3 is a schematic sectional view showing a third embodiment of the non-failsafe type door machine of fireproof door of the present invention.

FIG. 3 a is a partially enlarged view of the embodiment in FIG. 3, showing that the clutch mechanism is in engaged state.

FIG. 3 b is a partially enlarged view of the embodiment in FIG. 3, showing that the clutch mechanism is in released state.

FIG. 4 is a schematic sectional view showing a fourth embodiment of the non-failsafe type door machine of fireproof door of the present invention.

Claims

1. A door machine (1) of a fireproof door, comprising: a housing (10) for supporting said door machine (1);an input axle (17) pivotally disposed on said housing (10), one end of said input axle (17) being connected with a brake mechanism (27);a driving mechanism (28) for a driving force to actuate said brake mechanism (27) so as to transfer the driving force for rotating said input axle (17);an output axle (11) pivotally disposed on said housing (10), said output axle (11) comprising a first end (110) and a second end (112), said first end (110) being fixed with an output wheel (111) for rolling up the fireproof door to open the latter;a central axle (13) pivotally disposed on said housing (10), one end of said central axle (13) being coupled to said second end (112) of said output axle (11) and the other end of said central axle (13) being fixed with an end disc (15); anda clutch mechanism (23) having a sliding sleeve (14) fitted on said central axle (13), said sliding sleeve (14) being selectively movable between a first set point and a second set point on said central axle (13), one end of said sliding sleeve (14) being provided with a first gear disc (141), the other end of said input axle (17) being provided with a second gear disc (171), said first gear disc (141) being engaged with said second gear disc (171) and selectively connected to said end disc (15) of said central axle (13); when said sliding sleeve (14) being located at said first set point, said first gear disc (141) is connected with said end disc (15) of said central axle (13) so that said central axle (13) is linked up with and rotated by said input axle (17); when said sliding sleeve (14) being located at said second set point, said first gear disc (141) is disengaged from said end disc (15);wherein said brake mechanism (27) comprises a first bushing (271) and a torsion spring (272), said first bushing (271) being fitted on said input axle (17) and one end portion of said first bushing (271) being fixed to said housing (10), said torsion spring (272) being fitted on the other end portion of said first bushing (271); when said driving mechanism (28) being actuated, said torsion spring (272) is de-twisted and winds off around said first bushing (271) so that said input axle (17) is free to rotate; when said driving mechanism (28) being not actuated, the weight of the fireproof door is transferred to said input axle (17) so that said input axle (17) twists said torsion spring (272) to wind up to a effect that said torsion spring is tightly constricted on said first bushing (271) so as to brake said input axle (17).

2. The door machine (1) as claimed in claim 1, further comprising a reduction mechanism (21) assembled between said second end (112) of said output axle (11) and said central axle (13).

3. The door machine (1) as claimed in claim 2, further comprising a centrifugal type brake mechanism (25) coaxially fitted with said central axle (13); when the rotation speed of said central axle (13) reaches a predetermined value, said centrifugal type brake mechanism (25) brakes said central axle (13) by brakes on said housing (10).

4. The door machine (1) as claimed in claim 1, wherein said brake mechanism (27) comprises an inner race portion (273) and an outer race portion (274), said inner race portion (273) being fixed to said input axle (17) and said outer race portions (274) being fixed to said driving mechanism (28); said inner race portion (273) being coaxially fitted into said outer race portion (274); said inner race portion (273) having baffle plates (2731) provided respectively at two radial positions and said outer race portion (274) having pushing plates (2741) provided respectively at two radial positions, said baffle plates (2731) and said pushing plate (2741) being positioned on the same circumference; both ends of said torsion spring (272) having respectively protrusions (2721) protruding radially outward, one of said protrusions being staggered from the other protrusion in a circumferential direction by 90 degrees, each protrusion being placed between said baffle plates (2731) and said pushing plates (2741) adjacent to each other; when said driving mechanism (28) is actuated, said at least one of said pushing plates (2741) of said outer race portion (274) pushing one of said protrusion (2721) of said torsion spring (272) so that said torsion spring (272) is de-twisted, said input axle (17) being actuated by said torsion spring (272) so as to be rotated therewith; when said driving mechanism (28) is not actuated, the weight of the fireproof door is transmitted to said input axle (17), at least one of said baffle plate (2731) of said inner race portion (273) being abutted against said protrusions (2721) of said torsion spring (272) so that said torsion spring (272) being tightly constricted on said first bushing (271) to brake said input axle (17).

5. The door machine (1) as claimed in claim 4, wherein said driving mechanism (28) comprises an input wheel (281) to which said outer race portion (274) of said brake mechanism (27) is fixed.

6. The door machine (1) as claimed in claim 1, wherein said driving mechanism (28) comprises a bevel gear (281″), a capstan device (282) and a handle (283), said bevel gear (281″) being fixed to said outer race portion (274), said handle (283) being engaged with said bevel gear (281″), and said handle (283) being operatively connected to said capstan device (282); by actuating said capstan device (282) with said handle (283), said bevel gear (281″) being driven and rotated by said capstan device (282).

7. The door machine (1) as claimed in claim 4, wherein said clutch mechanism (23) is an electromagnetic clutch comprising an electromagnet (231), an active disc (233) and an elastic element (143), said electromagnet (231) being assembled on said housing (10), said active disc (233) being arranged adjacent to one side of said electromagnet (231), said elastic element (143) being fitted on said sliding sleeve (14); one end of said elastic element (143) being abutted against said sliding sleeve (14) while the other end of said elastic element (143) being abutted against said housing (10); when said electromagnet (231) is energized, said electromagnet (231) attracts said active disc (233) and moves said sliding sleeve (14) to said first set point so that said first gear disc (141) is coupled with said end disc (15); when said electromagnet (231) is de-energized, said elastic element (143) bias said sliding sleeve (14) to said second set point so that said first gear disc (141) is disengaged from said end disc (15).

8. The door machine (1) as claimed in claim 1, wherein said clutch mechanism (23) further comprises a delay circuit (C1) formed by a plurality of capacitors, said delay circuit (C1) energizing said electromagnet (231) in an event of power interruption.

9. The door machine (1) as claimed in claim 1, wherein said clutch mechanism (23) is a mechanical type clutch comprising a shift lever (243), a limit ring (241) and an elastic element (143), a partition plate (101) being extended vertically in said housing (10) and the other end of said sliding sleeve (14) slidably penetrating through an end face of said partition plate (101); an actuation plate (242) being assembled on one end of said shift lever (243), said actuation plate (242) having a hill shaped convex face (242a) projecting from one side thereof, said actuation plate (242) being fitted on said other end of said sliding sleeve (14) at said hill shaped convex face (242a) and placed between said limit ring (241) and the end face of said partition plate (101); the other end of said shift lever (243) being extended out of said housing (10); said elastic element (143) being disposed and compressed between said first gear disc (141) and said partition plate (101) so that said sliding sleeve (14) is normally located at said first set point; when said shift lever (243) is actuated, said convex face (242a) of said actuation plate (242) is abutted against said limit ring (241) so as to move said sliding sleeve (14) to said second set point.

10. The door machine (1) as claimed in claim 9, wherein said clutch mechanism (23) further comprises a guiding element (26), a sliding element (261), a compression spring (262) and a fusible link (263), said guiding element (26) being assembled on said housing (10), said sliding element (261) penetrating through said guiding element (26) and being slidable therein, one end of said sliding element (261) being arranged adjacent to said shift lever (243) and the other end of said sliding element (261) being connected to said fusible link (263), one end of said compression spring (262) being connected to said guiding element (26) and the other end of said compression spring (262) being connected to said sliding element (261) so that said sliding element (261) has a tendency to normally urged toward the shift lever (243) by said compression spring (262); when the ambient temperature exceeds the fusing point temperature of said fusible link (263), said fusible link (263) is melted down, and said sliding element (261) is urged toward said shift lever (243) by the elastic force of said compression spring (262) and strikes said shift lever (243) so that said sliding sleeve (14) is moved to said second set point.