Abstract:
A foldable boarding ramp is operatively connected to a door opening provided in a body and is selectively extendable to the ground. The foldable boarding ramp is stored in a folded state inside a fairing covering a connecting portion between the body and a main wing. Thus, a reduction in the space of a passenger compartment and a cargo compartment due to the storage of the folded boarding ramp is prevented. In addition, an increase in air resistance can be suppressed without providing a dedicated fairing for covering the boarding ramp. Further, an interlocking member connects together a door for opening and closing the door opening and the boarding ramp when the door is opened. The boarding ramp may be automatically deployed to improve convenience.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2006-103268 filed on Apr. 4, 2006 the entire contents of which are hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a boarding ramp device for an aircraft that includes a body, a main wing, and a fairing for covering a connecting portion between the body and the main wing. The fairing bulges in a lower face of the body. 
   2. Description of the Related Art 
   U.S. Pat. No. 4,014,486 and Japanese Patent Application Laid-open No. 4-230495 disclose a device in which a boarding ramp that is stored in a folded state in a body is deployed from a door opening formed in the body to the ground. The boarding ramp is stored in a folded state in view of the fact that there is a distance between the door opening and the ground. Thus, it is difficult for passengers to directly get on and off the aircraft without the use of a boarding ramp. 
   In addition, U.S. Pat. No. 4,453,684 discloses a device in which a door for opening and closing a door opening formed in a body is divided into a door upper-part and a door lower-part. A boarding ramp is provided on an inner surface of the door lower-part. 
   Further, U.S. Pat. No. 4,440,364 discloses a device that includes a boarding ramp that is extendable from a stored position along a lower face of a body to a use position wherein the boarding ramp projects sideward of the body. A dedicated fairing is provided in the body so as to cover the boarding ramp in the stored state. 
   However, U.S. Pat. No. 4,014,486 and Japanese Patent Application Laid-open No. 4-230495 have a problem wherein the space for a passenger compartment or a cargo compartment of the aircraft is decreased by the boarding ramp because the boarding ramp in the folded state is stored inside the aircraft. 
   Also, the boarding ramp described in U.S. Pat. No. 4,453,684 has a problem that the device is applicable only to a small-sized aircraft wherein distance between the lower end of the door opening and the ground is about the length of the door lower-part because the boarding ramp is provided on the inner face of the door lower-part. 
   Further, the boarding ramp described in U.S. Pat. No. 4,440,364 has a problem in that the dedicated fairing for covering the boarding ramp in the stored position is required to be provided on the lower face of the body, which increases air resistance. 
   SUMMARY OF THE INVENTION 
   The present invention has been achieved in view of the above circumstances. It is an object of an embodiment of the present invention to accommodate a foldable boarding ramp of an aircraft without reducing the space inside a body or increasing air resistance. 
   In order to achieve the above object, according to an embodiment of the present invention, there is provided a boarding ramp device for an aircraft that includes a body, a door opening provided in the body, a door for opening and closing the door opening, a main wing, and a fairing for covering a connecting portion between the body and the main wing. The fairing bulges in a lower face of the body, wherein the boarding ramp device comprises a foldable boarding ramp which connects the door opening to the ground, and which is stored inside the fairing in a folded state. 
   With this arrangement, the foldable boarding ramp connecting the door opening provided in the body to the ground is stored in the folded state inside the fairing covering the connecting portion between the body and the main wing. Thus, it is possible to prevent a reduction in the space of a passenger compartment and a cargo compartment due to the folded boarding ramp. Also, an increase in air resistance can be suppressed without providing a dedicated fairing for covering the boarding ramp. 
   According to an embodiment of the present invention, interlocking means connects the door and the boarding ramp so that the boarding ramp is deployed in association with the opening of the door. 
   With this arrangement, the door which opens and closes the door opening and the boarding ramp are connected together by the interlocking means so that the boarding ramp is automatically deployed when the door is opened, thereby improving convenience. 
   According to an embodiment of the present invention, the interlocking means comprises a clutch mechanism for releasing interlocking between the door and the boarding ramp. 
   With this arrangement, since a clutch mechanism for releasing interlocking between the door and the boarding ramp is provided in the interlocking means, even if the boarding ramp is locked in the folded state and can not be deployed, the door can be opened by releasing the interlocking between the door and the boarding ramp using the clutch mechanism, thereby enabling ingress and egress of passengers. 
   Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
       FIG. 1  is a perspective view of a body front portion of an aircraft; 
       FIG. 2  is an enlarged view taken from Arrow  2  in  FIG. 1 ; 
       FIG. 3  is an enlarged view taken from Arrow  3  in  FIG. 1 ; 
       FIG. 4  is an enlarged view taken from Arrow  4  in  FIG. 2 ; 
       FIG. 5  is a sectional view taken along a line  5 - 5  in  FIG. 4  (clutch engaged state); 
       FIG. 6  is a sectional view taken along a line  6 - 6  in  FIG. 5 ; 
       FIG. 7  is a sectional view taken along a line  7 - 7  in  FIG. 5 ; 
       FIG. 8  is a sectional view taken along a line  8 - 8  in  FIG. 5 ; 
       FIG. 9  is a view for explaining the operation corresponding to  FIG. 5  (clutch non-engaged state); 
       FIG. 10  is a view taken from Arrow  10  in  FIG. 3 ; and 
       FIG. 11  is a view for explaining the operation when a boarding ramp is deployed. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   As shown in  FIG. 1 , a connecting portion between a lower part of a body  11  and a main wing  12  of an aircraft is shaped by a fairing  13 . The fairing  13  bulges outwardly from the surface of the body  11  and continues to the surface of the main wing  12  so as to suppress an increase in drag caused by interference between air flowing around the body  11  and air flowing around the main wing  12 . A door  15  opens and closes a door opening  14  formed in a side face of the body  11  forward of a front edge of the main wing  12 . The door  15  can be opened outwardly of the body  11  with an unillustrated hinge provided as a fulcrum at an upper end of the door  15 . The manually opened and closed door  15  is provided with a window  16 , a handle  17  for opening the door  15  from outside the aircraft, a shaping portion  18  constituting a part of the fairing  13 , and a damper  19  for reducing a force required for opening and closing. Provided below the door opening  14  is a cover  20  constituting a part of the fairing  13  and capable of being opened and closed. A boarding ramp  21  is stored inside the cover  20  in a folded state. When the door  15  is opened, the cover  20  is opened downwardly in association with the opening, and the boarding ramp  21  is automatically deployed toward the ground. 
   As shown in  FIG. 2 , the door  15  is connected to the boarding ramp  21  through interlocking means  22 . The interlocking means  22  includes a driving pulley  23  provided at an upper part of the door opening  14 , and a driven pulley  24  provided in the boarding ramp  21  and connected through a cable  25  to the driving pulley  23 . An intermediate portion of the cable  25  is guided by a plurality of intermediate pulleys  27  provided in an annular body frame  26  along the rear edge of the door opening  14 . 
   As illustrated in  FIGS. 2 and 4  to  8 , a structure with regard to the driving pulley  23  will be described. 
   A pipe-shaped support shaft  33  is fixed in an axis L direction to a bracket  32  provided in a longitudinal member  31  extending in the forward/rearward direction along the upper edge of the door opening  14 . The driving pulley  23  and a clutch ring  34  are rotatably supported on the outer circumference of the support shaft  33  and independently from each other. A cylinder portion  35   a  of a driven arm  35  is fitted through a key groove  35   b  and a key  36  in the outer circumference of the clutch ring  34 . The clutch ring  34  is connected to the cylinder portion  35   a  of the rotating arm  35  that is not capable of relative rotation but is capable of sliding in the direction of the axis L. Three recess portions  34   c  formed at the lower end of the clutch ring  34  are opposed to three projections  23   a  formed on the upper face of the driving pulley  23  so that they are engaged with each other. 
   A clutch shaft  37  is slidably fitted inside the pipe-shaped support shaft  33  in the axis L direction and is biased downwardly by a spring  39  provided under compression between the clutch shaft  37  and an end plate  38  fixed to the upper end of the support shaft  33 . A pin  40  implanted in the clutch shaft  37  slidably penetrates a long hole  33   a  formed in the support shaft  33  in the direction of the axis L and is fitted in an annular guide hole  34   a  formed in the clutch ring  34 . A pin hole  34   b  penetrates the clutch ring  34  in the radially outward direction from the guide hole  34   a  in order to assemble the pin  40 . A lever  41  is fitted in a slit  33   b  formed at the lower end of the support shaft  33 , and is pivotally supported by a pin  42  so as to be capable of oscillation. A contact portion  41   a  at the base end of the lever  41  contacts the lower end of a clutch shaft  37 . The clutch ring  34 , the clutch shaft  37 , the spring  39  and the lever  41  constitute a clutch mechanism  47 . 
   A driving arm  43  is provided in an upper part of the door  15  so as to loosely penetrate the opening  31   a  of the longitudinal member  31  and extends into the bracket  32 . The tip end of the driving arm  43  and the tip end of the driven arm  35  are connected to opposite ends of a connecting rod  44  through ball joints  45  and  46 . 
   As illustrated in  FIGS. 3 and 10 , the structure of the boarding ramp  21  will be described. 
   Base ends of a pair of swing arms  53  are fixed to opposite ends of a support shaft  52  rotatably supported by a pair of brackets  51  provided on the body  11 . Base ends of the support links  56  are fixed to opposite ends of a rotating shaft  55  rotatably supported by brackets  54  provided on the body  11 . Fixed to the rotating shaft  55  are the driven pulley  24  and the base ends of a pair of crank links  57 . The tip ends of the crank links  57  and intermediate portions of the swing arms  53  are connected to each other through pins  58 , drive links  59  and pins  60 . Base ends of an upper step  61  are connected through pins  62  to the intermediate portions of the swing arms  53 . The tip ends of the support links  56  are connected to the intermediate portions of the upper step  61  through pins  63 . 
   An intermediate portion of each connecting link  65  having a base end pivotally supported through a pin  64  at the tip end of the upper step  61  and an intermediate portion of each extend link  67  having a base end pivotally supported through a pin  66  at the tip end of the swing arm  53  are pivotally supported through a pin  68 . Stoppers  69  are provided at the tip ends of the swing arms  53  so as to define rotational limit positions of the extend links  67 . Base ends of support links  70  are pivotally supported through pins  71  at the tip ends of the connecting links  65 . Intermediate portions of a lower step  72  are pivotally supported through pins  73  at the tip ends of the support links  70 . The base ends of the lower step  72  are pivotally supported through pins  74  at the tip ends of the extend links  67 . 
   The tip end of the swing arm  53  and a bracket  75  provided on the inner face of the cover  20  are linked to each other through a ball joint  76 , a cover opening/closing rod  77  and a ball joint  78 . 
   The following is a description of the operation of the embodiment provided with the above construction. 
   In normal operation, the clutch mechanism  47  of the interlocking means  22  is in an engagement state shown in  FIG. 5  where projections  23   a  of the driving pulley  23  are engaged with recess portions  34   c  of the clutch ring  34 . When the door  15  is manually opened in this state, the driving arm  43  provided in the door  15  is moved in the direction of Arrow A 1  in  FIG. 5 , and the arm portion  35   c  of the driven arm  35  is moved in the direction of Arrow A 2  in  FIG. 4  through the connecting rod  44 . As a result, in  FIG. 5 , the clutch ring  34  is rotated around the support shaft  33  through the key  36  and the key groove  35   b  formed on the inner circumferential face of the cylinder portion  35   a  of the driven arm  35 . In addition, the driving pulley  23 , having the projections  23   a  engaged with the recess portions  34   c  of the clutch ring  34 , is rotated around the support shaft  33  (see Arrow A 3  in  FIG. 4 ). When the clutch ring  34  is rotated around the support shaft  33 , the rotation of the clutch ring  34  is not inhibited because the pin  40  slides along the annular guide hole  34   a  of the clutch ring  34 . 
   When the driving pulley  23  of the interlocking means  22  is rotated in this way, the driven pulley  24  is rotated in the direction of Arrow A 4  in  FIGS. 3 and 10  through the cable  25  guided by the intermediate pulleys  27 . As a result, the crank links  57  are rotated through the rotating shaft  55  integral with the driven pulley  24 , and the swing arms  53  are rotated around the support shaft  52  in the direction of Arrow A 5  through the drive links  59  connected to the crank links  57 . In association with this rotation of the swing arms  53 , the support links  56 , the connecting links  65 , the extend links  67  and the support links  70  are deployed as sequentially shown in  FIG. 11A ,  FIG. 11B ,  FIG. 11C  and  FIG. 10 . 
     FIGS. 3 and 10  show a state where the boarding ramp  21  is fully deployed. In this state, the upper step  61  and the lower step  72  are horizontal so as to enable ingress and egress of passengers. With deployment of the boarding ramp  21 , the cover  20  constituting a part of the fairing  13  is opened downwardly through the cover opening/closing rod  77 . When the door  15  is closed, the driving pulley  23  and the driven pulley  24  are rotated in the direction reverse to the above-described direction, whereby the boarding ramp  21  in the deployed state is stored and the cover  20  is closed. 
   Since the boarding ramp  21  can be automatically deployed and stored as described above with the opening and closing of the door  15 , the convenience can be improved as compared with the case where they are separately carried out. 
   If the boarding ramp  21  is locked in the stored state for some reason, there is a possibility that the door  15  can not be opened or closed because the door  15  and the boarding ramp  21  are connected together by the interlocking mechanism  22 . In this case, the clutch mechanism  47  provided in the driving pulley  23  is disengaged so that the driving pulley  23  is capable of idle rotation to release the interlocking between the door  15  and the boarding ramp  21 , whereby only the door  15  can be opened and closed. 
   More specifically, as shown in  FIG. 9 , when the lever  41  is operated in the direction of Arrow A 6 , a contact portion  41   a  of the lever  41  moves the clutch shaft  37  in the direction of Arrow A 7  against an elastic force of the spring  39 . This movement of the clutch shaft  37  slides the pin  40  in the long hole  33   a  of the support shaft  33 , and the clutch ring  34  engaged with the pin  40  is moved while the key  36  is guided by the key groove  35   b  of the driven arm  35 . As a result, the engagement between the recess portions  34   c  of the clutch ring  34  and the projections  23   a  of the driving pulley  23  is released, whereby the clutch mechanism  47  is brought into a non-engaged state. 
   In this state, even if the driving pulley  23 , connected to the fixed boarding ramp  21  through the cable  25  becomes unrotatable, the door  15  can be opened and closed without any problem, because the clutch ring  34  which is operative in association with the opening and closing of the door  15  through the driving arm  43 , the connecting rod  44 , the driven arm  34  and the key  36  is separated from the driving pulley  23 , thereby avoiding a situation where the passengers cannot get on or off the aircraft. 
   Therefore, since the foldable boarding ramp  21  connecting the door opening  14  of the body  11  and the ground is stored in the folded state inside the fairing  13  covering the connecting portion between the body  11  and the main wing  12 , the folded boarding ramp  21  does not reduce the space for the passenger compartment or the cargo compartment in the body  11 . Moreover, a dedicated fairing for covering the folded boarding ramp  21  is not needed, thereby suppressing an increase in air resistance. 
   The embodiment of the present invention has been described above, but various changes in design can be made to the present invention without departing from the subject matter thereof. 
   For example, in the embodiment, the boarding ramp  21  is arranged on the front edge side of the main wing  12 , but it may be arranged on the rear edge side of the main wing  12 . 
   Also, in the embodiment, the door  15  is manually opened and closed, but it may be opened and closed by an actuator. 
   The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.