Abstract:
When a single door for opening and closing an opening in a body is opened outward with its lower part as a fulcrum, a plurality of plate-shaped steps of a foldable boarding ramp provided on an inner face of the door are swung in association with one another from a stored position along the inner face of the door to a deployed position to be used for ingress and egress of the passengers. Since the boarding ramp is folded into the stored position, it does not impair the space of a passenger compartment. Further, since the steps are folded into a position so as not to interfere with a window provided in an upper part of the door, they do not give an oppressed feeling to the passengers in the passenger compartment. The step is deployed to cover the window provided in the upper part of the door during use.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a boarding ramp device for an aircraft wherein a single door is provided that includes a window in its upper part for opening and closing an opening in a body of the aircraft. The door is pivotally supported at its lower part by the body with a foldable boarding ramp being provided on an inner face of the door. 
   2. Description of Background Art 
   An aircraft such as a business passenger aircraft having a body of a relatively small diameter includes a boarding ramp on an inner face of a door (face opposed to a passenger compartment) in order to open and close an opening provided in a body for ingress and egress of passengers. U.S. Pat. No. 2,910,255 and U.S. Pat. No. 4,086,726 disclose a boarding ramp provided on an inner face of the door, wherein when the door that is pivotally supported at its lower end by the body is opened outwardly and an upper end of the door nears the ground, the ramp is diagonally positioned so as to connect the opening of the body to the ground. 
   However, the boarding ramp described in U.S. Pat. No. 2,910,255 and U.S. Pat. No. 4,086,726 projects into the passenger compartment from the inner face of the door in the state when the door is closed, leading to a problem that a space in the passenger compartment is oppressed. Also, the exposed boarding ramp impairs the appearance of the passenger compartment, leading to a possibility that the clothes of the passengers may be smeared with mud or the like adhering to the boarding ramp. Further, a window can not be provided in the door due to an obstruction by the boarding ramp. Thus, a problem results wherein the passengers have an oppressed feeling. 
   In this situation, Beechcraft SUPER KING AIR of Raytheon Aircraft Company employs a boarding ramp including a door pivotally supported at its lower end by an aircraft body with a plurality of steps swingably supported at their base ends by the inner face of the door. The steps are folded along the inner face of the door when the door is closed and the steps forms the boarding ramp by swinging into a deployed position when the door is opened. 
   The boarding ramp of SUPER KING AIR can effectively use the space of the passenger compartment since the steps can be folded, but does not yet solve the problems that the boarding ramp impairs the aesthetic appearance of the passenger compartment. In addition, the door does not have a window which leads to an oppressed feeling to the passengers. 
   SUMMARY OF THE INVENTION 
   An embodiment of the present invention provides a boarding ramp device for an aircraft which does not impair the space of a passenger compartment, has an excellent appearance, and does not give an oppressed feeling to passengers. 
   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 wherein a single door includes a window in its upper part that opens and closes an opening in a body of the aircraft. The door is pivotally supported at its lower part by the body. A foldable boarding ramp is provided on an inner face of the door, wherein the boarding ramp includes a plurality of plate-shaped steps pivotally supported on the inner face of the door, wherein the steps are capable of swinging in association with one another between a stored position along the inner face of the door and a deployed position used for getting on and off by passengers. The steps are folded into the stored position so as not to interfere with the window, and the steps are deployed into the deployed position so as to cover the window. 
   With this arrangement, when the single door for opening and closing the opening in the body is opened outwardly with its lower part as a fulcrum, the plurality of plate-shaped steps of the foldable boarding ramp provided on the inner face of the door are swung in association with one another from the stored position along the inner face of the door to the deployed position used for getting on and off by passengers. Since the boarding ramp is folded into the stored position, they do not impair the space of the passenger compartment. In addition, since the steps are folded into the stored position where they do not interfere with the window provided in the upper part of the door, an oppressed feeling is not given to the passengers in the passenger compartment. Further, since the steps are deployed into the deployed position so as to cover the window provided in the upper part of the door, the passengers can step on the steps without being obstructed by the upper part of the door provided with the window. 
   According to an embodiment of the present invention, in addition to the first feature, the boarding ramp further includes a door handle pivotally supported by the body with a door driving link having one end pivotally supported by the door handle and the other end pivotally supported by the door. An upper-step driving link includes one end pivotally supported by the door driving link with an upper step having one end pivotally supported by the other end of the upper-step driving link and an intermediate part pivotally supported by the lower part of the door. A support link includes one end pivotally supported by the door and the other end pivotally supported by the upper step. An intermediate/lower-step driving link includes one end pivotally supported by the support link with a first gear rotatably supported at a rotational support point in the door with the other end of the intermediate/lower-step driving link is pivotally supported at a position eccentric from the rotational support point of the first gear. An intermediate step is pivotally supported by an intermediate part of the door with a second gear fixed to a support shaft of the intermediate step and meshed with the first gear and a first sprocket fixed to the support shaft of the intermediate step. A lower step is pivotally supported at a position below a lower end of the window provided in the upper part of the door. A second sprocket is fixed to a support shaft of the lower step with an endless chain wound around the first and second sprockets. 
   With this arrangement, since the door handle and the door are connected together by the door-driving link, the door can be opened and closed by operating the door handle. In addition, since the upper step is connected to the door-driving link through the upper-step driving link, the upper step can be swung between the stored position and the deployed position in association with the opening and closing of the door. Further, since the intermediate step is connected through the intermediate/lower-step driving link and the first and second gears to the support link connected to the upper step, and the intermediate step is connected to the lower step through the first and second sprockets and the endless chain, the intermediate step and the lower step can be swung between the stored position and the deployed position in association with the opening and closing of the door. 
   According to another embodiment of the present invention, the upper step includes an upper step inner part having one end pivotally supported by the door, and an upper step outer part having one end pivotally supported by the other end of the upper step inner part and the other end pivotally supported by the other end of the support link. The upper step inner part and the upper step outer part are folded so that they overlap with each other in the stored position. 
   With this arrangement, since the upper step is formed by the upper step inner part and the upper step outer part which are folded so that they overlap with each other in the stored position, the upper step can be further compactly stored. 
   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 partial perspective view of a front part of a body of an aircraft including a boarding ramp device according to an embodiment of the present invention; 
       FIG. 2  is an enlarged view of Part  2  in  FIG. 1 ; 
       FIG. 3  is a view taken from Arrow  3  in  FIG. 2  (door in fully opened state); 
       FIG. 4  is a view taken from an arrow of  4 - 4  line in  FIG. 3 ; 
       FIG. 5  is a view taken from an arrow of  5 - 5  line in  FIG. 3 ; 
       FIG. 6  is an enlarged view of Part  6  in  FIG. 3 ; 
       FIG. 7  is an action explanatory view corresponding to  FIG. 3  (door in half opened state); 
       FIG. 8  is a view for explaining the operation corresponding to  FIG. 3  (door in fully closed state); and 
       FIG. 9  is a perspective view showing an inner face of the door in the fully closed state. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , an opening  11   a  is formed on a left side face of a front part of a body  11  of an aircraft such as a business passenger aircraft, the opening  11   a  being opened and closed by a door  12  constituting a part of the body  11 . A foldable boarding ramp  16  having an upper step  13 , an intermediate step  14  and a lower step  15  are provided on an inner face of the door  12  (face opposed to a passenger compartment). A door front side pocket  17  and a door rear side pocket  18  for storing articles are provided on opposite front and rear edges of the door  12 . The upper step  13 , the intermediate step  14  and the lower step  15  of the boarding ramp  16  are deployed into a state available for getting on and off by passengers when the door  12  is fully opened and stored into a position along the inner face of the door  12  and between the door front side pocket  17  and the door rear side pocket  18  (see  FIGS. 8 and 9 ). 
   In the specification, the “upper” and the “lower” in the door  12  are defined as the “upper” and the “lower” in a state where the door  12  is closed. Thus, a window  19  of the door  12  is provided at the upper part of the door  12 , and a hinge line  20  (see  FIG. 3 ) about which the door  12  is opened and closed is provided at the lower end of the door  12 . However, the naming of the upper step  13 , the intermediate step  14  and the lower step  15  are based on a state where the door  12  is opened, that is, the upper step  13  is provided at the lower part of the door  12 , the intermediate step  14  at the intermediate part of the door  12  and the lower step  15  at the upper part of the door  12 , respectively. 
   Next, the structure of the boarding ramp  16  will be described with reference to  FIGS. 2 to 6 . In  FIGS. 3 ,  7  and  8 , black circles denote fulcrum pins which are unmovable with respect to the body  11  or the door  12 , and white circles denote fulcrum pins which are movable with respect to the body  11  or the door  12 . 
   One end of a door handle  23  is pivotally supported by a bracket  21  provided at the opening  11   a  of the door  12  through a fulcrum pin  22 . A door driving link  25  is pivotally supported at its one end by the door handle  23 . The other end of the door driving link  25  is pivotally supported through a fulcrum pin  27  by a bracket  26  provided on the inner face of the door  12 . One end of an upper-step driving link  28  is pivotally supported through a fulcrum pin  29  at an intermediate part of the door driving link  25 . 
   The upper step  13  comprises an upper step inner part  13   a  and an upper step outer part  13   b . The upper step inner part  13   a  has one end pivotally supported through fulcrum pins  31 ,  31  by brackets  30 ,  30  provided on the inner face of the door  12 . The upper step outer part  13   b  has one end pivotally supported through a fulcrum pin  32  by the other end of the upper step inner part  13   a . A fulcrum pin  33  supports a portion of the upper step inner part  13   a  near its one end and the other end of the upper-step driving link  28 . A support link  36  is pivotally supported at its one end by a bracket  34  provided on the inner face of the door  12  through a fulcrum pin  35 . The other end of the support link  36  is pivotally supported by the other end of the upper step outer part  13   b  through a fulcrum pin  37 . 
   As clearly shown in  FIGS. 2 and 6 , a first gear  40  includes a sector gear that is pivotally supported by a bracket  38  provided on the inner face of the door  12  through a fulcrum pin  39 . An intermediate/lower-step driving link  42  is pivotally supported at its one end by the intermediate part of the support link  36  through a fulcrum pin  41 . The other end of the intermediate/lower-step driving link  42  is pivotally supported through a fulcrum pin  43  at a tip end of an arm  40   a  extending from the first gear  40 . One end of the intermediate step  14  is fixed to a first support shaft  44  bridging the door front side pocket  17  and the door rear side pocket  18 . A second gear  45  is fixed to the first support shaft  44 , and meshed with the first gear  40 . 
   One end of the lower step  15  is fixed to a second support shaft  46  bridging the door front side pocket  17  and the door rear side pocket  18 . An endless chain  49  is wound around a first sprocket  47  fixed to the first support shaft  44  and a second sprocket  48  fixed to the second support shaft  46 . 
   An intermediate part of a handrail  52  is pivotally supported through a fulcrum pin  51  by a bracket  50  provided at the opening  11   a  of the door  12 . A handrail driving link  54  is pivotally supported at its one end by one end of the handrail  52  through a fulcrum pin  53 . The other end of the handrail driving link  54  is pivotally supported through the fulcrum pin  55  at the intermediate part of the door handle  23 . 
   Next, the operation of the embodiment of the present invention having the above-described construction will be described. 
   As shown in  FIGS. 8 and 9 , when the door  12  is at the fully closed position where the door  12  closes the opening  11   a  in the body  11 , the boarding ramp  16  are compactly stored in a folded state between the door front side pocket  17  and the door rear side pocket  18  on the inner face of the door  12 . Among the components of the folded boarding ramp  16 , the lower face (face not stepped on by feet) of the lower step  15  covering the central part of the door  12  and the upper face (face stepped on by feet) of the upper step outer part  13   b  covering the lower part of the door  12  are seen from the passenger compartment side. 
   In the stored state of the boarding ramp  16 , the window  19  located in the upper part of the door  12  is completely exposed, giving no oppressed feeling to the passengers in the passenger compartment. Also, the lower step  15  covering the inner face of a part of the door  12  lower than the window  19  has a lower face (face not stepped on by feet when getting on and off) opposed to the passenger compartment side, providing no fear that mud or the like adhering thereon smears the clothes of the passengers. Further, if the shape of the lower face of the lower step  15  is finished smoothly along the lines of the door front side pocket  17  and the door rear side pocket  18 , the appearance becomes excellent in cooperation with a small protrusion amount of the lower step  15  into the passenger compartment. Furthermore, although the upper face (face stepped on by feet when getting on and off) of the upper step outer part  13   b  is exposed in the lower part of the door  12 , the upper step outer part  13   b  has a small area and is located at a position close to the floor of the passenger compartment, providing no fear that the passengers have discomfort even if a small amount of mud adheres to the clothes of the passengers. 
   Moreover, since the door handle  23  and the handrail  52  are stored in a clearance between the door front side pocket  17  and the folded boarding ramp  16 , they do not project into the passenger compartment to obstruct or impair the appearance. 
   When the door handle  23  is lowered down in the direction of Arrow a on the fulcrum pin  22  in  FIG. 7  in order to open the fully closed door  12 , the door driving link  25  descends in the direction of Arrow b, so that the door  12  connected through the fulcrum pin  27  to the door driving link  25  is opened outward in the direction of Arrow c about the hinge line  20 . At this time, since the door driving link  25  is relatively rotated in the direction of Arrow d with respect to the door  12 , the upper-step driving link  28  is pulled in the direction of Arrow e, so that the upper step inner part  13   a  is swung in the direction of Arrow f about the fulcrum pin  31 . As a result, the upper step outer part  13   b  is swung in the direction of Arrow g, and the support link  36  is swung in the direction of Arrow h on the fulcrum pin  35 , so that the upper step inner part  13   a  and the upper step outer part  13   b  which has been folded in the overlapping manner are deployed so as to be located on the same plane. 
   As is apparent from  FIGS. 6 and 7 , the intermediate/lower-step driving link  42  is moved in the direction of Arrow i by the support link  36  swinging in the direction of Arrow h, thereby pushing the arm  40   a  of the first gear  40  to rotate the first gear  40  in the direction of Arrow i, so that the second gear  45  meshed with the first gear  40  is rotated together with the first support shaft  44  in the direction of Arrow k. As a result, the intermediate step  14  fixed to the first support shaft  44  is swung and deployed in the direction of Arrow m. Also, when the first sprocket  47  is rotated together with the first support shaft  44  in the direction of Arrow k, the second sprocket  48  and the second support shaft  46  are rotated in the direction of Arrow n by the endless chain  49 , so that the lower step  15  fixed to the second support shaft  46  is swung and deployed in the direction of Arrow o. 
   As illustrated in  FIG. 7 , when the door handle  23  is swung in the direction of Arrow a, the handrail driving link  54  is pulled down in the direction of Arrow p, and the handrail  52  is pulled by the handrail driving link  54  and swung in the direction of Arrow q about the fulcrum pin  51  to project out of the opening  11   a  in the body  11  to the outside of the aircraft. 
   In this way, when the door  12  reaches the fully opened position shown in  FIG. 3 , the upper end of the door  12  is lowered and stopped at a position close to the ground, and the lower step  15 , the intermediate step  14  and the upper step  13  respectively assume horizontal postures and are diagonally aligned at predetermined pitches, whereby the passengers can getting on and off the aircraft through the opening  11   a  in the body  11 . At this time, the handrail  52  extends diagonally along the alignment direction of the lower step  15 , the intermediate step  14  and the upper step  13  so that the passengers going up and down the boarding ramp  16  can easily grab the handrail  52  with one hand. 
   Since the lower step  15  is formed longer than the upper step  13  and the intermediate step  14 , the lower step  15  extends to the upper end of the door  12  while fully covering the window  19  provided in the upper part of the door  12  in the state where the boarding ramp  16  is deployed. Thus, the passengers can step on the lower step  15  without being obstructed by the upper part of the door  12 . 
   Also, since the upper step  13  is divided into two parts, that is, the upper step inner part  13   a  and the upper step outer part  13   b , and folded and stored so that they overlap with each other, the boarding ramp  16  can be made to be stored in a compact manner. 
   When the door  12  is closed from the fully opened state shown in  FIG. 3  through the half opened state shown in  FIG. 7  to the fully closed state shown in  FIG. 8 , the boarding ramp  16  is folded from the deployed state to the stored state through the process in the reverse order of the above-described process. When the passengers are onboard in the aircraft, the door  12  can be opened and closed by operating the door handle  23  from inside the aircraft. When the passengers are not onboard, the door  12  can be directly opened and closed while grabbing the door  12  from outside the aircraft. Also in this case, the boarding ramp  16  is automatically deployed or stored with the opening and closing of the door  12 . 
   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, the door  12  is manually opened and closed by operation of the handle  23  in the embodiment, but the door  12  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.