[invention Title]

AUTOMATIC CLOSE DEVICE AND SYSTEM OF FIRE DOOR

[Technical Field] Generally, an automatic closing device for fire doors is installed at a fire door to prevent the spread of fire, when a fire occurs in a building. The automatic closing device for fire doors of the present invention automatically closes a fire door, in response to an emergency signal. The present invention relates generally to an automatic closing device and system for fire doors. More particularly, the present invention relates to an automatic closing device and system for fire doors, capable of automatically closing a fire door which is open at normal times, in response to a fire indication, such as smoke or heat. The present invention allows a person who must evacuate to manually open or close the closed fire door, even though the fire door has been closed in response to a fire. Further, according to the present invention, a pair of left and right door panels of the fire door is automatically closed in a predetermined order so that the fire door is completely sealed. [Background Art]

Generally, an automatic closing device for fire doors functions to prevent the spread of a fire, in addition to blocking the movement of smoke, when a fire occurs in a

building. That is, the automatic closing device for fire doors prevents smoke or flames from spreading, and allows persons who are in the building to rapidly evacuate to a safe place through an emergency passageway which is isolated from smoke and flames by the closure of the fire door. The fire door is constructed so that it is opened at normal times and is automatically closed in response to an emergency signal, in the event of emergency due to smoke or heat.

According to this invention, when it is required to open a fire door that has been closed due to the occurrence of a fire, the closed fire door may be manually opened and closed. The fire door having a pair of left and right door panels may close in a predetermined order so as to be completely sealed. In order to seal the fire door having a pair of door panels, steps are provided on the central portion of the fire door where the door panels contact each other. In this case, the door panels must be sequentially closed, thus making it possible to completely seal the fire door. If the door panels close in reverse order, the door panels may not be in close contact with each other, due to the steps provided on the central portions of a pair of door panels . [Disclosure] [Technical Problem] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior

art, and an object of the present invention is to provide an automatic closing device and system for fire doors, which allows a fire door that has been closed due to the occurrence of a fire to be manually opened, when an evacuating person desires to re-open the fire door, and which is constructed so that a pair of door panels closes in a predetermined order.

A conventional device automatically closing a fire door in response to an emergency signal, such as one generated in response to heat or smoke, is problematic in that the number of components of the automatic closing device is large, so that manufacturing costs of the closing device are high. Further, the conventional automatic closing device has an unstable structure, so that the closing device may easily break down as time passes. However, the present invention has a simple structure using a rack and a pinion, so that the automatic closing device of this invention will break down even if it is used for a lengthy period of time.

Further, the present invention is characterized in that a sequential closing unit is linked to a pair of door panels of the fire door. In order to more completely seal the fire door having a pair of door panels, steps are provided on contacting portions of the door panels. In this case, the door panels must close in a predetermined order so that the door panels are in close contact with each other, thus completely closing the fire door. According to the prior art, the sequential closing unit is manufactured

independently from the components of the fire door, so that it must be installed at the center of the fire door. However, the present invention includes a very simple sequential closing unit which is operated in conjunction with the door panel that closes first, so that it is possible to considerably reduce manufacturing costs of the automatic closing system. Further, according to this invention, the reliability and durability of the sequential closing unit are enhanced. According to this invention, even if the fire door has been automatically closed, evacuating persons can easily open the fire door by hand. The present invention provides such an automatic closing device and system for fire doors. [Technical Solution] In order to accomplish the object, the present invention provides an automatic closing device for fire doors, connected via an actuating bar to a door closure unit which closes a fire door using hydraulic pressure, thus automatically closing the fire door, the automatic closing device including an actuating unit having an actuating shaft, a rack slidably mounted on an outer circumference of the actuating shaft, a pinion operated in conjunction with the rack, and a pair of support walls; and a door lock unit to lock or unlock a locking latch using a locking unit, the locking latch provided on an end of the actuating shaft of the actuating unit.

Further, the present invention provides a system for sequentially closing a fire door including a first door panel and a second door panel, wherein a first automatic closing device and a second automatic closing device are mounted to the first door panel and the second door panel, respectively, in such a way as to be opposite each other, and a sequential closing unit is provided at a position between the first automatic closing device and the second automatic closing device, and is operated in conjunction with the door closing devices .

[Advantageous Effects]

As described above, the present invention provides an automatic closing device for fire doors, including a simple actuating unit having a rack and a pinion, and a door lock unit which automatically releases a locking unit of a fire door in response to a signal indicating the detection of smoke or heat, thus having a very simple structure which is free from malfunction.

Further, even if the fire door has been closed due to the occurrence of a fire, a person can open the closed fire door by hand if he or she desires to open the fire door. Especially, a pair of door panels of the fire door sequentially closes in a predetermined order, so that the door panels are in close contact with each other, and the fire door is sealed completely. Thus, the marketability of the automatic closing device is enhanced.

The construction and operation of the present invention allow the closed fire door to be manually opened when a person desires to open a fire door which has been closed due to the occurrence of a fire. Particularly, the two door panels of the fire door sequentially close in a predetermined order, so that the door panels are in close contact with each other and the fire door is sealed completely, thus the marketability of the automatic closing device for fire doors is enhanced. [Description of Drawings]

FIG. 1 is a perspective view to show an automatic closing device for fire doors, according to an embodiment of the present invention;

FIG. 2 is a view to show the construction of the automatic closing device of the present invention;

FIG. 3 is a view to illustrate a rack and a pinion constituting an actuating unit of the present invention;

FIG. 4 is a view to illustrate the connection of the automatic closing device with a door closure unit; FIG. 5 is a view to illustrate a door lock unit;

FIGS. 6 and 7 are views to illustrate the operation of the door lock unit;

FIG. 8 is a perspective view of a limit switch;

FIG. 9 is a view to show the construction of an automatic closing device for fire doors, according to another embodiment of the present invention;

FIGS. 10 and 11 are views to illustrate the automatic closing device shown in FIG. 9;

FIGS. 12 and 13 are views to show the construction of an automatic closing device for fire doors, according to a further embodiment of the present invention;

FIGS. 13 through 18 are views to show the construction of an automatic closing device for fire doors, according to a still further embodiment of the present invention; and

FIGS. 19 through 26 are views to illustrate an automatic closing system for fire doors, according to the present invention. [Mode for Invention]

The automatic closing device for fire doors, according to the present invention, is connected to a door closure unit which closes a fire door using hydraulic pressure. The automatic closing device which automatically closes the fire door is connected to the door closure unit via an actuating bar.

The actuating bar protrudes outwards from the automatic closing device, according to the present invention. The rotating force of the door closure unit is transmitted to the actuating bar, and the rotating force of the actuating bar is transmitted to the automatic closing device of the present invention.

The automatic closing device for fire doors, according to the present invention, includes an actuating unit and a door lock unit.

At normal times, the fire door is open. However, when a fire occurs, the door lock unit of the automatic closing device is operated in response to an external signal, such as one indicating the detection of smoke or heat. When the locked state of the actuating unit, whose movement is limited by a locking unit provided on the door lock unit, is released, the actuating bar is ready to operate. Further, the fire door starts to close by the door closure unit which is installed on a fire wall.

The actuating unit includes a box-shaped main body; a pair of support walls each having a shaft hole, and installed in the main body in such a way as to be spaced apart from each other by a predetermined distance; an actuating shaft inserted into the shaft hole of each of the support walls, and moving in a horizontal direction; a rack positioned between the support walls and mounted on an outer surface of the actuating shaft, and sliding along the actuating shaft within a predetermined distance; and a pinion engaging with the rack and rotated by movement of the rack. An actuating bar is rotated in conjunction with the pinion, and passes through the main body in such a way as to protrude outwards from the main body by a predetermined length.

Further, a slide control means may be provided at a predetermined position on the actuating shaft to control a sliding length of the rack.

The slide control means includes a thread provided on the outer surface of the actuating shaft, and having a predetermined length; and a nut fastened to the thread, so that the sliding length of the rack is determined, according to a position of the nut fastened to the thread.

According to the present invention, the door lock unit includes a locking latch provided on an end of the actuating shaft of the actuating unit; a locking hook rotated a predetermined angle about a hinge, with a seating groove being formed on the locking hook; a spring to elastically bias the locking latch; an actuating part to control rotation of the locking latch; and a motor-driven device to operate the actuating part in response to an external signal. Further, a manual lock releasing part may be further provided on the actuating part of the door lock unit in such a way as to protrude outwards. Further, the door lock unit may include a pair of bent parts each rotating about a hinge, a first end of each of the bent parts being seated in a first groove of the locking latch; a spring to elastically support a second end of each of the bent parts; and a releasing part mounted to an end of a motor shaft, with a step provided on an outer circumference of the releasing part.

According to this embodiment, a locking latch mounted to an end of the actuating shaft is formed using a plate having a predetermined thickness, with first grooves formed on both sides of the locking latch, and a second groove formed on a front end of the locking latch.

In this embodiment, the releasing part is rotatable by a motor. When the releasing part seated in the second groove of the locking latch is rotated, the locking latch is rotated by the step of the releasing part. Through such a movement, the locking latch is released from ends of the bent parts.

The door lock unit may include a bent locking hook having in a predetermined portion thereof a through hole. According to this embodiment, the locking latch mounted to an end of the actuating shaft constituting the actuating unit is formed using a plate having a predetermined thickness, and includes locking grooves on both sides of the locking latch. Further, a pulling strap is provided at a predetermined position on the actuating shaft, so that the actuating shaft is rotated by pulling the pulling strap, and the locking latch is released from the locking hook as the actuating shaft rotates. The pulling strap may be pulled by pulling the handle or rotating the motor.

The automatic closing device may further include a limit switch which is provided at a predetermined position on the door lock unit, and detects operation of the actuating bar.

In the present invention, when the fire door includes a pair of door panels, that is, first and second door panels, the door panels must be sequentially closed. The present invention provides a sequential closing unit so as to sequentially close the door panels.

The sequential closing unit of this invention is located at a middle position between a first automatic closing device mounted to the first door panel and a second automatic closing device mounted to the second door panel. A first actuating shaft of the first automatic closing device and a second actuating shaft of the second automatic closing device extend longitudinally while one end of each of the first and second actuating shafts passes through a main body of an associated automatic closing device. The sequential closing unit is installed at the position where the first and second actuating shafts meet. When the first automatic closing device is operated in response to an external signal, so that the first door panel is closed, the sequential closing unit is operated in conjunction with the moving first actuating shaft. By the operation of the sequential closing unit, a space for moving the second actuating shaft is defined in the sequential closing unit. As the second actuating shaft moves into the space, the second door panel is closed.

According to this embodiment, the sequential closing unit may comprise a recess-type closing unit or a rotary-type closing unit.

The recess-type sequential closing unit includes a casing; a seat provided in the casing and elastically supported by a spring; a protrusion integrated with the seat, and protruding out of the casing; and an insertion hole formed in the casing.

The rotary-type sequential closing unit includes a box-shaped casing; a rotary part seated in the casing in such a way as to rotate about a hinge; a coil spring to elastically bias the rotary part in a predetermined direction; and a stop step to limit rotation of the rotary part. The sequential closing unit further comprises a sensor to detect movement of a second actuating shaft.

The present invention is characterized in that the sequential closing unit is operated in conjunction with the first actuating shaft, and the second actuating shaft is operated in conjunction with the sequential closing unit.

Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components.

FIG. 1 is a perspective view of an automatic closing device for a fire door 500, according to an embodiment of the present invention, and FIG. 2 is a perspective view to show the construction of the automatic closing device for the fire door 500, which is shown in FIG. 1.

As shown in the drawings, the automatic closing device for the fire door 500, denoted by reference numeral 10, includes an actuating unit and a door lock unit. The actuating unit includes a main body 110, support walls 120, an actuating shaft 130, a rack 140, and a pinion 150.

The main body 110 has the shape of a box which is hollow therein to accommodate several components. An end of the actuating shaft 130, which will be described later, and an actuating bar 160 operated in conjunction with the pinion 150 protrude out of the main body 110 (see, FIG. 1) .

The pair of support walls 120 each having a shaft hole is installed in the main body 110. The support walls 120 are spaced apart from each other by a predetermined distance. The actuating shaft 130 is slidably inserted into the support walls 120. The rack 140 has the shape of a hexahedron, with a gear being formed on a surface of the hexahedron to serve as a rack, and a through hole being formed through the central portion of the hexahedron such that the actuating shaft 130 passes through the hexahedron. Thus, the rack 140 supported between the support walls 120 may slide up to a predetermined distance. In order to control the sliding

distance of the rack 140, a thread 170 is provided on the outer surface of the actuating shaft 130, and a nut 180 is fastened to the thread 170. Thus, a user can adjust the sliding length of the rack 140 by rotating the nut 180. The pinion 150 is mounted adjacent to the rack 140, so that the pinion 150 may be rotated by the movement of the rack 140. Further, the pinion 150 is coupled to the actuating bar 160, and the actuating bar 160 passes through the main body 110 to be connected to a door closure unit 600. FIG. 4 is a view to illustrate the connection of the automatic closing device with the door closure unit. Generally, the door closure unit 600 comprises a hydraulic closure device. The door closure unit is installed between the fire door and a fire door frame. Thus, when the fire door is opened, the door is intended to be closed by hydraulic pressure of the door closure unit. Currently, such a door closure unit is widely used.

FIG. 5 shows an embodiment of the door lock unit. A locking unit, which limits the movement of the actuating shaft 130 of the actuating unit, is provided at a predetermined position on the door lock unit 200. As shown in the drawings, a locking latch 210 is provided on an end of the actuating shaft 130 of the actuating unit. When the locking latch 210 is pushed into the door lock unit, the locking latch 210 is automatically locked by the locking unit

of the door lock unit, due to the elastic force of the door lock unit.

When a manual lock releasing part 260 is operated to manually release the locking state, the locking state is released.

FIGS. 6 and 7 are views to illustrate the operation of the door lock unit. The door lock unit includes a locking hook 220, a spring 230 which provides an elastic force to the locking hook 220 to rotate the locking hook 220, and an actuating part 240 which controls the rotation of the locking hook 220.

As shown in FIG. 6, when the locking latch 210 provided on an end of the actuating shaft 130 of the actuating unit is pushed into the locking unit, the locking hook 220 of the door lock unit is rotates as shown in FIG.

6b. The locking latch 210 is seated into a seating groove

225 which is formed on the locking hook 220. The locking hook 220 includes the seating groove 225 in which the locking latch 210 is seated, and is constructed to rotate about a hinge at a predetermined angle.

The locking hook 220 locks or unlocks the locking unit using the spring 230 mounted to the locking hook 220.

FIG. 8 is a view to illustrate a limit switch which may be mounted to the door lock unit 200. According to this invention, the limit switch 700 is mounted on the door lock unit 200, and detects where the actuating shaft 130 is fixed

or moved. A signal generated by the limit switch 700 is transmitted to the exterior, thus indicating the operated state of the automatic closing device 10 for the fire door 500. The operation of the automatic closing device for the fire door according to an embodiment of the present invention will be described below.

First, when a user pushes the end of the actuating shaft 130 exposed to a side of the main body 110 so that the locking latch 210 is seated into the door lock unit 200, the locking latch 210 is secured by the seating grooved of the locking hook 220 of the door lock unit 200. Thus, movement of the actuating shaft 130 is impossible.

In such a state, when a signal indicating the occurrence of a fire is transmitted, a solenoid valve 250 is operated, thus moving an adjusting bar 260. By the movement of the adjusting bar 260, the actuating part 240 is rotated. As the actuating part 240 rotates, the locking hook 220 is rotated by the spring 230, so that it enters the state of FIG. 6. After the locking latch 210 is released, the actuating shaft 130 may move.

Since the actuating shaft 130 may move, the pinion 150 engaging with the rack 140 may rotate. Due to the rotating pinion 150, the actuating bar 160 also rotates. Thus, the fire door 500 is closed by the door closure unit 600 which is mounted to the fire door 500. Even when the fire door 500 is

closed, the rack 140 may freely move between the support wall 120 and the nut 180, so that the actuating bar 160 may rotate, thus allowing a person to open the fire door and escape. Further, when a user desires to keep the fire door open, one end of the actuating shaft 130 exposed to the outside of the main body 110 is inserted to be secured to the door lock unit 200. At this time, the actuating bar 160 cannot rotate, so that the fire door 500 remains in an open state.

FIGS. 9, 10, and 11 show another embodiment of a door lock unit, according to the present invention.

The door lock unit of the automatic closing device 10 for the fire door is denoted by reference numeral 300. The door lock unit 300 includes a locking latch 310, bent parts 320, a spring 330, and a releasing part 340. The locking latch 310 is formed using a plate having a predetermined thickness, and is mounted to the end of the actuating shaft 130. First grooves 311 are formed on both sides of the locking latch 310, and a second groove 312 is formed on the front end of the locking latch 310.

A pair of bent parts 320 has an "L" shape, and rotates about a hinge 350 at a predetermined angle. A first end of each bent part 320 is seated in the corresponding first groove 311 of the locking latch 310. Further, a spring 330 is provided to connect second ends of the bent parts 320 to

each other. The releasing part 340 is mounted to an end of a motor shaft, with a step provided on an outer circumference of the releasing part 340.

By such a construction, the releasing part 340 is rotatable by the motor. When the releasing part 340 seated in the second groove 312 of the locking latch 310 rotates, the locking latch 310 is rotated by the step of releasing part 340. At this time, the locking latch 310 secured by the first ends of the bent parts 320 is released, so that the actuating shaft 130 may move.

Further, FIGS. 12 and 13 are views to illustrate a further embodiment of a door lock unit of the automatic closing device for the fire door, according to the present invention. The door lock unit of this invention moves an actuating part 240 using a force generated in response to a signal from a smoke or heat sensor. As the actuating part 240 moves, a locking hook 220 is rotated by the elastic force of a spring. Thereby, the locking unit is released.

The actuating part 240 may be released by a releasing part. Of course, the actuating part 240 may be automatically released by operating a solenoid actuator or a motor, in response to a signal generated in response to the detection of smoke or heat.

According to this invention, an operating mechanism, which is operated in response to a signal that indicates the occurrence of a fire after sensing smoke or heat, may use a

motor or a solenoid actuator. That is, when a fire indication is generated, the actuating part 240 is operated by rotating a shaft of a motor having a cam or a step or the operating force of a solenoid actuator, so that the locking latch is automatically released.

In order to ensure the reliable operation of the actuating part 240, one end of the actuating part 240, which is denoted by reference numeral 250, may be formed to be long. Such a construction allows the actuating part to be operated by amplified force using the action of a lever. Such a long end of the actuating part allows the actuating part to be easily automatically operated by the force of the motor or solenoid actuator.

Of course, it is necessary to be able to manually operate the door lock unit of the automatic closing device for the fire door, according to the present invention.

Further, by operating the manual lock releasing part 260, the locked state of the actuating part may be manually released. The manual lock releasing part 260 usually protrudes out of the door lock unit.

In a detailed description, the manual lock releasing part 260 protruding out of the door lock unit may be provided under the actuating part 240. By manually rotating the manual lock releasing part 260 about a hinge, the actuating part 240 is operated, so that the locking unit is released.

The door lock unit used in this invention is operated to respond to an emergency indicated by smoke or heat.

In the case of an emergency, the door lock unit according to the present invention operates the actuating unit so that the fire door is automatically closed.

FIGS. 14 through 18 show a further embodiment of a door lock unit. As shown in the drawings, one end of the actuating shaft 130 has the shape of a flat plate so that a locking latch maintains a constant thickness. A locking groove 820 is formed on the outer circumference of the locking latch. Further, a "ϋ"-shaped locking hook is provided at a position where the end of the actuating shaft is locked.

Further, as shown in FIG. 18, an adjusting handle 830 protrudes from the outer circumference of the actuating shaft

130. The adjusting handle 830 is secured to a pulling strap

840. Further, the pulling strap 840 reciprocates a predetermined length by a motor. Thus, when the motor is operated in response to an external signal, the pulling strap 840 moves a predetermined length. By the movement of the pulling strap 840, the actuating shaft 130 is rotated by a predetermined angle (90 degrees), so that the flat end rotates 90 degrees.

That is, when the actuating shaft 130 is seated in a through hole 810 of the locking hook 800, and thereafter is rotated at 90 degrees, in response to an external signal, the

actuating shaft 130 is removed from the locking hook 800, so that the fire door is closed. Further, a user can return the actuating shaft 130 to an original position thereof using the adjusting handle 830. FIGS. 19 to 22 are views illustrating a sequential closing system for fire doors, according to the present invention, which sequentially closes a pair of door panels, in conjunction with the automatic closing device for fire doors. When the fire door 500 having the pair of door panels is closed, the fire door 500 must be sequentially closed so as to be sealed completely. The automatic closing system of this invention, when applied to this case, will be described in detail with reference to FIGS. 20 to 22.

FIGS. 20, 21, and 22 are views to illustrate a first automatic closing device 11, a second automatic closing device 12, and the sequential closing system which is operated to sequentially close the fire door. As shown in FIG. 20, 21, and 22, the fire door includes a pair of door panels, that is, a first door panel 501 and a second door panel 502. Door closure units 600 are mounted to the first and second door panels 501 and 502, respectively. The first and second automatic closing devices 11 and 12 are coupled to the door closure units 600 in such a way as to be opposite each other. One end of a first actuating shaft of the first automatic closing device 11 and one end of a second actuating

shaft 132 of the second automatic closing device 12 pass through main bodies of the corresponding closing devices. The first and second actuating shafts are connected to a sequential closing unit 400 which is provided at a middle position between the first and second actuating shafts.

According to the present invention, the sequential closing unit may comprise a recess-type closing unit or a rotary-type closing unit.

The recess-type closing unit includes a casing, a seat, a protrusion, and an insertion hole. The seat is provided in the casing, and is elastically supported by a spring. The protrusion is integrated with the seat, and protrudes out of the casing. The insertion hole is formed in the casing. Of course, a sensor which detects the movement of the second actuating shaft may be provided at a predetermined position on the sequential closing unit.

According to this embodiment, the sequential closing unit includes a casing 400, a protrusion 410 which protrudes out of the casing, a seat 430 which is connected to the protrusion and supports the protrusion in the casing, a spring 450 which elastically supports the seat, and an insertion hole. When the protrusion protruding out of the casing is retracted into the casing by a roller provided on an end of the first actuating shaft, empty space is formed in the casing. Due to this space, the insertion hole provided

at a predetermined position in the casing is opened. The second actuating shaft is inserted into the insertion hole. Since the second actuating shaft is moved by the insertion hole, it is possible to close the second door panel. That is, the automatic closing device is operated in response to an external signal, and the first and second actuating shafts 131 and 132 are operated in conjunction with each other by the sequential closing unit of this invention. In a detailed description, unless the first actuating shaft retracts the protrusion of the sequential closing unit into the casing, the second actuating shaft 420 cannot move because of the seat 430 provided in the casing. However, when the first actuating shaft 130 moves a predetermined distance, the first door panel 501 is closed. Simultaneously, the first actuating shaft 130 moves, so that the protrusion 410 is retracted into the casing. Due to the space defined by the retraction of the protrusion, the insertion hole is opened. Thereby, the second actuating shaft 420 may be inserted into the insertion hole, so that the second door panel 502 is also closed.

That is, in response to an external signal, the first door panel 501 is first closed. Next, the second door panel 502 is closed. Further, a limit switch is attached to a side surface of the casing. Thus, when the second actuating shaft is inserted, the limit switch 460 is operated, so that whether the second door panel is closed is determined.

FIG. 23 illustrates another embodiment of a sequential closing unit, that is, a rotary-type closing unit, according to this invention. The rotary-type closing unit includes a box-shaped casing, a rotary part which is rotatably seated in the casing by a hinge, a coil spring which biases the rotary part in a predetermined direction, and a stop step which limits the rotation of the rotary part.

Of course, a sensor which detects the movement of the second actuating shaft may be further provided on the rotary- type closing unit.

As shown in the drawings, the rotary-type closing unit includes a box-shaped casing having insertion holes at positions where one end of the first actuating shaft 131 and one end of the second actuating shaft 132 are inserted. An "L"-shaped rotary part 1010 supported by a hinge 1050 is installed in the casing. Further, a coil spring 1030 is secured to the hinge 1050 so as to bias the rotary part 1010 in a predetermined direction. The rotation of the rotary part 1010 is limited by a stop step 1020. The operation of this invention constructed as described above will be described with reference to FIGS. 24 to 26. When the first door panel is closed, the first actuating shaft 131 is moved. By the movement of the first actuating shaft 131, the rotary part 1010 is rotated. The second actuating shaft 132 moves into space which is created by the rotation of the rotary part 101, so that the second

door panel is closed. Further, the movement of the second actuating shaft is detected by a sensor 1040.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.