Note: Descriptions are shown in the official language in which they were submitted.
CA 02952490 2016-12-20
1
A maintenance step for a helicopter
The present invention is related to a maintenance step for a
helicopter. The present invention is further related to a helicopter with
such a maintenance step.
Maintenance steps are generally present on all helicopters and
can be provided in different numbers on the helicopters dependent e.
g. on an underlying helicopter size. For instance, three maintenance
steps per side are provided on the H135 and H145 from Airbus
Helicopters and more steps can be provided e. g. on the NH90 from
Airbus helicopters.
In general, maintenance steps are adapted to allow
maintenance crew members to get in a position where they can fulfil
required maintenance tasks, especially checks at the helicopter's
engines and main gear box. Thus, the maintenance steps must be
suitable to provide access to respective upper decks of helicopters so
that they are always located outside of a helicopter, namely in a
lateral shell of the helicopter's fuselage.
More specifically, maintenance steps are usually part of a
fuselage of a helicopter and can be visible to the outside, i. e.
distinguishable from the fuselage. However, they are preferably
hidden and retracted, i. e. made flush to an outer surface of the
fuselage, in flight operation of the helicopter.
An exemplary maintenance step on a fuselage of a helicopter
comprises a trap-like single step that is pivotally mounted to a
support element and connected to a rotatable stirrup, which is
storable on the support element. However, due to the dimensions of
the rotatable stirrup, the trap-like single step must be designed
CA 02952490 2016-12-20
2
relatively large such that the trap-like single step can be stored
thereon. This, nevertheless, results in additional weight, costs and
integration problems of the maintenance step. Furthermore, this
maintenance step cannot be used for an undercut in a lateral shell of
a helicopter's fuselage, as the support element cannot be adapted
thereto in a suitable manner.
The document US 2011/0272524 Al describes an integrated
maintenance step on a fuselage of a helicopter. This maintenance
step comprises a casing that is integrated into a lateral shell of the
fuselage for access from outside of the helicopter, and a single step
that is pivotally mounted in the casing. In other words, the
maintenance step is foldable and flush to an outer surface of the
fuselage of the helicopter. The term "flush" means that the outer
surface is smooth and the maintenance step is integrated into this
outer surface such that it is not distinguishable when observed from a
predetermined distance.
The document US 8,905,354 B1 describes a foldable step
assembly for a helicopter with a housing and a single support member
that is hingedly coupled to the housing by means of a shaft. The
support member is configured as a step support and a hand hold
device and it is adapted to rotate between a stored position and a
deployed position. Furthermore, a first locking feature is associated
with the support member and a second locking feature is associated
with the housing. Moreover, a spring is operably associated with the
support member and the housing such that the spring biases the first
locking feature towards the second locking feature.
However, the above described maintenance steps and step
assemblies only comprise foldable single steps that are folded, i. e.
li
CA 02952490 2016-12-20
3
turned around a single axis, in order to provide a step for getting
access to an upper deck of a helicopter. This kind of single step is,
nevertheless, only usable in a straight, middle area of a lateral shell
of a helicopter's fuselage. In case of an undercut in the lateral shell,
e. g. close to a bottom shell of the helicopter's fuselage, it is not
possible to use such a single step without major impact on style, loft
and integration in the helicopter. In particular, in case of such an
undercut in the lateral shell a single step that is arranged close to a
bottom shell of the helicopter's fuselage can simply be unusable or at
least not safely or ergonomically usable.
If, however, no other technical solution exists to integrate a
maintenance step on a lowest position in an undercut area, i. e. close
to a bottom shell of the helicopter's fuselage, so that only a
maintenance step in a higher position can be provided, an extra
device such as e. g. a small ladder that is placed in front of the
helicopter would be necessary to grant access to the maintenance
step in the higher position. This is, however, not acceptable if quick
access to an upper deck of the helicopter without additional devices
should be enabled.
It is, therefore, an object of the present invention to provide a
new maintenance step for a helicopter that is at least usable without
major restrictions on a lateral shell of a fuselage of a helicopter.
More specifically, according to the present invention a
maintenance step for a helicopter comprises a casing that is adapted
for integration into a lateral shell of a fuselage of a helicopter, and a
step member that is pivotally mounted to the casing. A stirrup unit is
pivotally mounted to the step member. The stirrup unit comprises at
I'
CA 02952490 2016-12-20
4
least a first and a second section, the second section being
telescopically mounted to the first section.
Preferably, such a maintenance step is installed on an outer
surface, i. e. an outer skin, of a helicopter's fuselage. A
corresponding installation location can preferentially be selected
arbitrarily and, thus, be along the whole fuselage. In current
configurations, this maintenance step is preferentially installed in
front and/or rear sections of a helicopter. Thereby, the maintenance
step can either be installed from an inside or an outside of the
helicopter.
According to one aspect of the present invention, the inventive
maintenance step can be installed as an integrated footstep for
undercut areas of a helicopter's fuselage. It has a very low negative
impact or no impact at all on fuel capacity, only a very low impact on
installation volume requirement and no impact at all on a required
crash behaviour of a helicopter's bottom shell. Furthermore, it
represents a light and cheap method for access to a helicopter's
upper deck that advantageously does not require additional ground
support equipment, such as a small ladder. Finally, the inventive
maintenance step is also useable with cold weather gloves, e. g. thick
winter gloves.
Advantageously, the inventive maintenance step combines two
separate step members that are even useable for undercut areas.
This means that there is no need for space allocation of an additional
lower maintenance step, such as e. g. a maintenance step on a
lowest position in an undercut area close to a bottom shell of a
helicopter's fuselage, as the stirrup unit would replace such an
additional lower maintenance step. Consequently, a key benefit of the
CA 02952490 2016-12-20
inventive maintenance step is to enable space savings for integration
of other equipment (e. g. fuel) and to allow provision of a
maintenance step in an area of a helicopter's fuselage, where
normally no integrated maintenance step can be installed.
5 Furthermore, the inventive maintenance step is easy to use for
operation and safe locking during flight operation of a helicopter. It
has a flat design for reduced space requirement inside the helicopter
and it provides modularity at minimum installation space for maximal
use. A further advantage of the inventive maintenance step is to get
more space available. Moreover, the costs for the inventive
maintenance step are decreased by approximately 50% and its weight
by approximately 9%, compared to a conventional maintenance step.
Finally, the inventive maintenance step can be provided with a plastic
locking device with very little weight and which is not harming the
lateral shell of the fuselage of the helicopter.
According to one aspect of the present invention, the
maintenance step has a geometrically equivalent interface to a lateral
shell of a fuselage of a corresponding helicopter for allowing modular
use for subsequent installation at a plurality of different existing
helicopters. Preferably, the casing of the inventive maintenance step
is integrated into a lateral shell of a fuselage of a helicopter for
access from outside. A first step, which is preferably implemented as
the step member with a stepping plate and a covering plate, is
preferentially pivotally mounted in the casing, e. g. around a first
axis. Preferably, the stepping plate is implemented as a full flat
stepping surface with anti-skid painting provided thereon for improved
safety during maintenance. The covering plate is preferentially
mounted to the stepping plate by at least one safety screw to provide
for the step member in its closed position a smooth surface in
CA 02952490 2016-12-20
6
alignment with the lateral shell of the fuselage of the helicopter.
Furthermore, the covering plate can be provided with an opening for a
locking device in order to allow for easily fixing the step member in its
closed position inside the fuselage. A second step, which is
preferably implemented as the stirrup unit, is preferentially pivotally
mounted on the first step, e. g. around a second axis, which can be
perpendicular, parallel or otherwise oriented with respect to the first
axis. The second step can preferentially be pivoted up to contact with
the first step.
Preferably, the stirrup unit is telescopic and can be extended to
its full length by at least two and, preferentially, three telescopic
elements. In other words, the stirrup unit preferably consists of
several telescopic elements, the material, number and lengths of
which can be adapted according to application-specific needs.
However, the lowest telescopic element in the stirrup unit is
preferentially formed in a U-shape for defining a lowest stepping area
of the stirrup unit. This lowest stepping area is preferably equipped
with anti-slip treatment for safe operation even in adverse condition.
Furthermore, securing pins in the telescopic elements are provided
according to one aspect of the present invention for securing the
length of the stirrup unit in extended form and for providing sufficient
strength during use. In addition, if necessary, a rope or rod, which is
preferably installed on the stirrup unit, can be provided for connection
to an attachment point provided on the fuselage of the helicopter in
order to provide additional stiffness.
According to one aspect of the present invention, the
maintenance step can be installed in different planes, i. e. at different
locations of a helicopter and, therefore, be pivoted around different
axes as well. Therefore, the casing is provided with a frame-like
CA 02952490 2016-12-20
7
support structure, i. e. a frame, and a rearward extension with lateral
sides, wherein the rearward extension with the lateral sides is
integrated into a lateral shell of the fuselage of the helicopter.
Preferably, a backside of the rearward extension is formed with at
least one overhang as a cost efficient support for the first step.
Furthermore, the lateral sides preferably comprise coaxial borings,
preferentially for bearings, and the first step is provided with
corresponding coaxial borings in lateral flanges. Pins, and more
specifically pivot pins, are preferably provided for insertion through
corresponding coaxial borings into the coaxial borings in the lateral
sides of the rearward extension for pivotal mounting of the first step,
i. e. its stepping plate, in the casing, and a retaining profile is
provided for securing the inserted pivot pins in their respective
positions. Preferably, wear resistant bearings are provided for
insertion into the corresponding coaxial borings of the lateral sides of
the rearward extension of the casing. The wear resistant bearings are
adapted for holding the pivot pins of the first step and, preferentially
together with washers at the inside of the lateral sides and coaxially
with the bearings, need no replacement during common life cycles of
a helicopter. Advantageously, no more than a single boring is
provided in the first step as the retaining profile prevents the pivot
pins from rotating relative to the lateral sides of the first step.
Preferably, the first step has a hinge mechanism with hinges
and hinge pins and the second step is provided with corresponding
counter parts of the hinge mechanism. Hinge pins or bolts are
preferentially provided for insertion through corresponding coaxial
borings provided in the hinges and the first and second steps. These
coaxial borings can be equipped with associated bearing elements for
pivotal mounting. Finally, in order to enable use of the inventive
CA 02952490 2016-12-20
8
maintenance step on different curvatures on the lateral shell of the
fuselage of the helicopter while still providing a stepping surface that
is oriented in parallel to the ground, shim plates can be installed to
the casing of the maintenance step.
According to a preferred embodiment of the invention, the
second section of the stirrup unit is at least approximately U-shaped
and provides an ascendable stepping area.
According to a further preferred embodiment of the invention,
the stepping area is provided with anti-slip means.
According to a further preferred embodiment of the invention,
the stirrup unit comprises at least one third section that connects the
first section to the second section. The at least one third section is
telescopically mounted to the first section and is further telescopically
mounted to the second section.
According to a further preferred embodiment of the invention,
the stirrup unit is provided with securing pins that are adapted for
restricting telescopic movement of the first, second and third sections
relative to each other.
According to a further preferred embodiment of the invention,
the step member is provided with anti-slip means.
According to a further preferred embodiment of the invention, a
locking device is provided for locking the step member in the casing
in a closed state of the maintenance step.
According to a further preferred embodiment of the invention,
the casing is provided with an overhang that is adapted for blocking
the step member in an opened state of the maintenance step.
CA 02952490 2016-12-20
9
According to a further preferred embodiment of the invention,
the step member comprises a stepping plate that is provided with a
covering plate. The covering plate is implemented as a filling part that
is adapted for creating at least approximately a continuous surface
with a lateral shell of a fuselage of a helicopter to which the
maintenance step is mountable.
According to a further preferred embodiment of the invention,
the covering plate is attached to the stepping plate by means of
associated fixing elements.
According to a further preferred embodiment of the invention, an
attachment rope or rod is provided. The attachment rope or rod is
adapted for securing the step member in an opened state of the
maintenance step to a lateral shell of a fuselage of a helicopter to
which the maintenance step is mountable.
According to a further preferred embodiment of the invention, a
retaining element is provided. The retaining element is adapted for
releasably retaining the stirrup unit at the step member in a retracted
state of the stirrup unit.
According to a further preferred embodiment of the invention,
shim plates are associated with the step member. The shim plates are
adapted for enabling a horizontal alignment of the step member
independent of a respective inclination angle of the casing.
According to a further preferred embodiment of the invention,
the casing is provided with at least one slope that is adapted for
preventing water accumulation in the casing.
li
CA 02952490 2016-12-20
The present invention further provides a helicopter with a
fuselage that comprises a lateral shell to which a maintenance step
as described above is mounted.
By way of example, a method of mounting an inventive
5
maintenance step to a lateral shell of a fuselage of a helicopter
according to the present invention is described hereinafter.
Furthermore, a method of dismounting such an inventive maintenance
step from a lateral shell of a fuselage of a helicopter according to the
present invention is described hereinafter.
10
Preferably, a method for mounting an inventive maintenance
step to a lateral shell of a fuselage of a helicopter comprises:
- inserting a rearward extension of an essentially rectangular
casing of the maintenance step into the prepared fuselage of
the helicopter,
- riveting an essentially rectangular frame of the essentially
rectangular casing flat against the lateral shell of the
prepared fuselage of the helicopter,
- mounting bearings into coaxial borings in lateral sides of the
rearward extension of the essentially rectangular casing, and
70 -
inserting pins from within a mid box through corresponding
coaxial borings into the coaxial borings in the lateral sides of
the rearward extension and clipping a retaining profile into
grooves at inwardly pointing ends of the inserted pins to fix
the inserted pins in their position.
Preferably, the retaining profile is held in its clipped position by
the covering plate of the maintenance step, which is biased against
the retaining profile after screwing by use of screws of the covering
plate to the step member of the maintenance step. Suitable telescopic
1,
CA 02952490 2016-12-20
11
elements are preferentially slid into each other and securing pins are
fixed. Furthermore, hinges are attached to the telescopic elements
and a step member of the maintenance step.
Advantageously, this method of mounting the inventive
maintenance step to a lateral shell of a fuselage of a helicopter is
particularly simple, fast and leads to provision of a highly reliable
maintenance step.
In addition, washers, preferably distance washers, can be
arranged inside the lateral sides and coaxially with the bearings
before insertion of pivot pins for low friction. Furthermore, a surface
opposite to a stepping area of a stepping plate of the step member
can be provided with a covering plate screwed with safety screws for
a smooth surface in alignment with the lateral shell of the fuselage of
the helicopter.
Preferably, a method for dismounting an inventive maintenance
step to a lateral shell of a fuselage of a helicopter comprises:
- unscrewing and removing the covering plate from the step
member, if applicable,
- withdrawing the retaining profile from its clipped position,
- taking the retaining profile out of the grooves at the inwardly
pointing ends of the inserted pivot pins,
- removing the pivot pins from their positions in the coaxial
borings, and
- taking the step member out of the prepared fuselage of the
helicopter.
Thus, the complete maintenance step can advantageously be
dismounted after removal of the retaining clips and displacement of
both pivot pins in the middle position.
CA 02952490 2016-12-20
12
Preferred embodiments of the invention are outlined by way of
example in the following description with reference to the attached
drawings. In these attached drawings, identical or identically
functioning components and elements are labeled with identical
reference numbers and characters and are, consequently, only
described once in the following description.
- Figure 1 shows a simplified perspective view of a helicopter
with a maintenance step according to the present invention,
- Figure 2 shows an enlarged detail of the helicopter of Figure 1
with the maintenance step in stored state,
- Figure 3 shows a perspective view of the maintenance step of
Figure 2 in deployed state, and
- Figure 4 shows an exploded view of the maintenance step of
Figure 3.
Figure 1 shows a rotary wing aircraft 1 with a plurality of
maintenance steps 4 that is exemplarily illustrated as a helicopter.
Thus, for purposes of simplicity and clarity, the rotary wing aircraft 1
is hereinafter referred to as the "helicopter" 1. The present invention
is, however, not limited to helicopters and can likewise be applied to
any other vehicle, in particular to a vehicle that requires one or more
maintenance steps, independent of a particular configuration thereof.
Illustratively, the helicopter 1 comprises a fuselage la that
defines a tail boom 1 b, which exemplarily comprises a tail wing 1 c
and a fin id. The tail boom lb may further be provided e. g. with a
horizontal stabilizer, a bumper and so on.
CA 02952490 2016-12-20
13
It should be noted that only the fuselage la with the tail boom
lb are shown in Figure 1 for purposes of simplicity and clarity of the
drawings. However, other conventional components, such as e. g. a
rotor of the helicopter 1, are not shown, as they are well-known to the
person skilled in the art and not part of the present invention and
would, thus, only unnecessarily encumber and complicate the
representation.
Illustratively, the fuselage la comprises at least two longitudinal
side walls, a board side wall respectively lateral shell 1g, which is
also referred to hereinafter as the "board side lateral shell 1g", and a
starboard side wall respectively lateral shell 1h, which is also referred
to hereinafter as the "starboard side lateral shell 1h", both of which
are preferably connected to the tail boom lb. The board side lateral
shell 1 g and the starboard side lateral shell lh exemplarily comprise
a plurality of doors and/or windows 2, a plurality of maintenance traps
3 and a plurality of emergency exits 5, which are e. g. at least partly
defined by the plurality of doors and/or windows 2.
The fuselage 1a illustratively further comprises an outer surface
if and preferably defines at least a drive system accommodating
region le and a cockpit, and may further define a passenger cabin
and/or a cargo compartment. However, for simplicity and clarity of the
description, such a cockpit, passenger cabin and cargo compartment
are not explained in greater detail.
The drive system accommodating region le preferably
accommodates one or more engines that are adapted for driving the
helicopter 1, e. g. by providing power to an associated power
distribution unit, such as a gearbox, which then provides this power to
a suitable propelling unit, such as e. g. a propeller, rotor or other.
CA 02952490 2016-12-20
14
Preferably, the one or more engines are embodied as air breathing
propulsion engines, such as diesel engines, gas engines, gas turbines
and so on, which combust a fuel/air mix for power generation.
However, as the air breathing propulsion engines as such are not part
of the present invention, they are not explained in greater detail for
brevity and conciseness.
According to one aspect of the present invention, the fuselage
la and, more generally the helicopter 1, is further provided with the
plurality of maintenance steps 4. Illustratively, the plurality of
maintenance steps 4 are shown on the board side lateral shell 1g and
comprise, by way of example, an upper step 4a, a middle step 4b and
a lower step 4c.
It should be noted that, by way of example, only the lower step
4c is embodied according to the present invention and described in
greater detail hereinafter, while the upper and middle steps 4a, 4b
can be implemented as conventional maintenance steps. However,
the upper and/or middle steps 4a, 4b may alternatively also be
embodied according to the present invention, i. e. have a
configuration that is at least similar to the configuration of the lower
step 4c as described below.
It should further be noted that the lower step 4c as described
hereinafter can also be integrated in other areas of the helicopter 1
where a direct integration of a step is not possible, e. g. in cowlings,
fairings, doors and/or ramps. It can further be used as a boarding
step, e. g. for pilot/co-pilot, and so on.
Figure 2 shows the maintenance step 4c of Figure 1, which is
mounted to the board side lateral shell 1g of the fuselage la of the
helicopter 1 of Figure 1. According to one aspect of the present
CA 02952490 2016-12-20
invention, the board side lateral shell 1g is provided with an
attachment point 13. The latter can e. g. be adapted for attachment of
an attachment rope or rod (17 in Figure 3) of the maintenance step 4c
for providing additional stiffness in operation. Therefore, the
5
attachment point 13 can be positioned in front, rear or below the
maintenance step 4c.
More specifically, the maintenance step 4c preferably comprises
a casing 6 that is adapted for integration into the board side lateral
shell 1g and a step member 7 that is pivotally mounted to the casing
10 6.
The casing 6 exemplarily comprises a frame-like support structure
6a, which is also referred to hereinafter as the "frame 6a". The latter
illustratively defines an inner opening 6b and is preferably closed by
a rear wall that closes up the board side lateral shell 1g. Thus, the
casing 6 defines a tray or bowl-like structure.
15 By
way of example, the casing 6 is integrated into the board
side lateral shell 1g such that the maintenance step 4c is mounted to
the board side lateral shell 1g. Illustratively, the maintenance step 4c
is shown in a closed state, wherein the step member 7 is arranged
inside the inner opening 6b of the frame 6a, and preferentially
completely accommodated therein. In this closed state, the step
member 7 is preferably locked in the casing 6 by means of a locking
device 8. The latter is preferentially mounted to the step member 7
and locked in the closed state as illustrated to a lock bar 8a that is
provided at the casing 6.
According to one aspect of the present invention, the step
member 7 comprises a stepping plate 7b that is provided with a
covering plate 7a. The covering plate 7a is preferably implemented as
a filling part that is adapted for creating at least approximately a
CA 02952490 2016-12-20
16
continuous surface with the board side lateral shell 1g. The covering
plate 7a is preferentially attached to the stepping plate 7b by means
of associated fixing elements 7c, such as e. g. screws, bolts or rivets.
Alternatively, the covering plate 7a and the stepping plate 7b can be
combined and/or integrated into a single component.
Preferably, the step member 7, and exemplarily the stepping
plate 7b, is pivotally mounted to the casing 6, as described below with
reference to Figure 4. For structurally supporting the step member 7,
it can be attached to the casing 6, e. g. by means of a rope that
interconnects the stepping plate 7b and the frame 6a of the casing 6.
The step member 7, and exemplarily the stepping plate 7b, is
preferably connected to hinges 9. By way of example, the hinges 9
comprise a first hinge 9a and a second hinge 9b. In the illustrated
closed state of the maintenance step 4c, the first hinge 9a defines an
upper hinge and the second hinge 9b defines a lower hinge.
According to one aspect of the present invention, the hinges 9a,
9b comprise associated clevises 10a, 10b, which are illustratively
pivotally mounted to corresponding hinge arms 11a, lib by means of
hinge pins 12. The hinge arms 11a, 11 b are preferably mounted to the
step member 7, and exemplarily to the stepping plate 7b, and
preferentially form an integral part thereof. In other words, the
stepping plate 7b and the hinge arms 11a, 1 1 b are preferably
implemented as a single one-piece component.
However, it should be noted that the hinges 9a, 9b are merely
illustrated by way of example and not for limiting the invention
accordingly. Instead, different kinds of hinge mechanisms can be
used, such as e. g. piano hinges, hinge lines and/or other hinge
elements.
CA 02952490 2016-12-20
17
Figure 3 shows the maintenance step 4c with the casing 6 and
the step member 7 of Figure 2 in an opened state. However, for
simplicity and clarity of the drawings, the maintenance step 4c is
shown without the board side lateral shell lg of the fuselage la of the
helicopter 1 of Figure 1.
In the opened state of the maintenance step 4c, the step
member 7 is pivoted relative to the frame 6a of the casing 6 such that
a plane defined by the stepping plate 7b of the step member 7 is now
illustratively at least approximately perpendicular to a plane defined
by the frame 6a. However, other angles between these planes can
likewise be realized, as described below with reference to Figure 4.
Preferably, the step member 7 is blocked in its illustrated
position by means of an overhang 6c of the casing 6. More
specifically, this overhang 6c is adapted for blocking the step member
7 in the opened state of the maintenance step 4c and defines together
with the frame 6a a receiving opening 6d, wherein a portion of the
step member 7 is illustratively received and blocked.
As described above with reference to Figure 2, the step member
7 and, exemplarily, the stepping plate 7b is connected via the
corresponding hinge arms 11 a, lib to the clevises 10a, 10b by means
of the hinge pins 12 such that the clevises 10a, 10b can be pivoted
relative to the corresponding hinge arms 11a, 11b. The clevises 10a,
10b are preferably further connected by means of additional hinge
pins 12 to a stirrup unit 15, which is, thus, pivotally mounted to the
step member 7.
The step member 7 thus defines a structural support for the
stirrup unit 15. However, other means of structural support of the
CA 02952490 2016-12-20
18
stirrup unit 15 instead of the step member 7 can likewise be provided,
such as a rope or rod.
It should be noted that, by way of example and not for limiting
the present invention accordingly, the stirrup unit 15 can be pivoted
relative to the step member 7 around an axis, which is exemplarily
perpendicular to an axis around which the step member 7 can be
pivoted relative to the casing 6. Alternatively, both axes are not
perpendicular and other angles, e. g. in a range between 300 and 60 ,
can likewise be implemented. Still alternatively, both axes can be
arranged in parallel and so on.
It should further be noted that the connection between the step
member 7 and the stirrup unit 15 is exemplarily embodied by means
of two times two hinges. However, the number of hinges can be
modified. For instance, instead of using two times two hinges, only a
total of two hinges can be used by modifying the step member 7 or
the stirrup unit 15. Such a modification is, nevertheless, readily
available to the person skilled in the art and, therefore, not further
described for brevity and conciseness.
According to one aspect of the present invention, the stirrup unit
15 comprises at least a first and a second section 15a, 15c. The first
section 15a is exemplarily pivotally mounted to the clevises 10a, 10b
by means of the hinge pins 12 at associated hinge connecting
portions 15d. The second section 15c is preferably telescopically
mounted to the first section 15a. Furthermore, the second section 15c
is preferentially at least approximately U-shaped and provides an
ascendable stepping area 15e, which is preferably provided with anti-
slip means 15f.
CA 02952490 2016-12-20
19
It should be noted that the step member 7, and preferentially the
stepping plate 7b, is preferably also provided with anti-slip means 7d.
These anti-slip means 7d as well as the anti-slip means 15f can be
implemented using any suitable anti-slip covering, coating or
treatment.
According to one aspect of the present invention, the stirrup unit
comprises at least one third section 15b that connects the first
section 15a to the second section 15c. The at least one third section
15b is preferably telescopically mounted to the first section 15a and
10 is further telescopically mounted to the second section 15c.
In Figure 3, the first section 15a exemplarily represents a
connection section that is connected to the step member 7 as
described above and that illustratively defines an upper section of the
stirrup unit 15. The third section 15b exemplarily represents an
15 optional extension section, which can also be omitted if a shorter
stirrup unit is required, and which illustratively defines a middle
section of the stirrup unit 15. The second section 15c exemplarily
represents an ascendable section that is e. g. ascendable by a
maintenance crew member and that illustratively defines a lower
section of the stirrup unit 15.
However, it should be noted that the stirrup unit 15 is only
shown by way of example with the three sections 15a, 15b, 15c, and
not for limiting the present invention accordingly. Instead, e. g.
additional extension sections and/or ascendable sections can be
provided to lengthen the stirrup unit 15 as required, up to forming a
ladder. Likewise, as mentioned above, the optional extension section
can be omitted. Similarly, the applied sections can be implemented
with different materials dependent, e. g., on an intended use.
CA 02952490 2016-12-20
Furthermore, more than one stirrup unit 15 can be integrated into the
maintenance step 4c.
It should further be noted, that instead of the described
modifications to the stirrup unit 15 alternatively the step member 7
5 can be modified. For instance, the step member 7 can be completely
omitted such that the stirrup unit 15 is directly integrated into the
board side lateral shell 1g of Figure 2, i. e. the casing 6. In this case,
the stirrup unit 15 may not be totally smooth/not visible from the
outside and not covered with an aerodynamic covering, such as the
10 covering plate 7a. Alternatively, the stirrup unit 15 can be covered by
such an aerodynamic cover for enabling a smooth outer skin of the
board side lateral shell 1g of Figure 2. In this case, the aerodynamic
cover could be double-used as stepping surface as well.
According to one aspect of the present invention, securing pins
15 16 are provided that are adapted for restricting telescopic movement
of the first, second and third sections 15a, 15b, 15c relative to each
other. More specifically, the securing pins 16 are preferably adapted
to block the stirrup unit 15 at least in an associated deployed state as
shown in Figure 3 and/or an associated retracted state. In the latter,
20 the securing pins 16 can be adapted for fixing the stirrup unit 15 in
its
retracted state and for preventing an undesired deployment.
For deploying the stirrup unit 15, the second section 15c can be
gripped, e. g. at the stepping area 15e, and pulled away from the first
section 15a. For retracting the stirrup unit 15, the second section 15c
can be gripped, e. g. at the stepping area 15e, and pushed towards
the first section 15a.
In its retracted state, the stirrup unit 15 can be stored on the
step member 7 and, more specifically, on the stepping plate 7b after
CA 02952490 2016-12-20
21
having been rotated towards the latter. Preferably, a retaining
element 14 is provided and illustratively rigidly attached to the
stepping plate 7b. The retaining element 14 is preferably adapted for
releasably retaining the stirrup unit 15 at the step member 7 in the
retracted state of the stirrup unit 15.
According to one aspect of the present invention, the stirrup unit
is provided with an attachment rope or rod 17. This attachment
rope or rod 17 is preferably adapted to support stepping loads and for
securing the step member 7 in the opened state of the maintenance
10 step 4c to the attachment point 13 of Figure 2 and, thus, to the board
side lateral shell 1g of the fuselage la of the helicopter 1 of Figure 1.
By way of example, the attachment rope or rod 17 is mounted to the
first section 15a of the stirrup unit 15 at an associated fixation
element (17a in Figure 4). Alternatively, an end stop can be
15 implemented into the step member 7 with a suitable locking device,
such that the attachment rope or rod 17 can be omitted.
Figure 4 shows the maintenance step 4c of Figure 3 for further
illustrating the covering plate 7a, the stepping plate 7b with the
integral hinge arms 11a, 11b, the fixing elements 7c, the locking
device 8, the clevises 10a, 10b, the hinge pins 12, the retaining
element 14, the three sections 15a, 15b, 15c of the stirrup unit 15,
the securing pins 16, the attachment rope or rod 17 and the fixation
element 17a. Moreover, the casing 6 with the overhang 6c and the
receiving opening 6d of the maintenance step 4c is also further
illustrated.
According to one aspect of the present invention, the casing 6 is
provided with at least one slope 6e that is adapted for preventing
water accumulation in the casing 6. The at least one slope 6e is
1,
CA 02952490 2016-12-20
22
preferably implemented such that water entering into the casing 6 is
forced to exit the casing 6 by means of gravity.
The casing 6 preferably further comprises fixations for retaining
pivot pins 18. These fixations can be implemented as openings or
borings in the casing's frame 6a, which accommodate the pivot pins
18. The latter are preferably adapted to engage associated receiving
openings 19 that are preferably provided in the stepping plate 7b and,
more generally, in the step member 7. Consequently, the pivot pins
18 are adapted to define pivot axes for the step member 7.
According to one aspect of the present invention, shim plates 20
are associated with the step member 7. The shim plates 20 are
preferably adapted for enabling a horizontal alignment of the step
member 7 independent of a respective inclination angle of the casing
6.
It should be noted that modifications to the above described
embodiments are within the common knowledge of the person skilled
in the art and, thus, also considered as being part of the present
invention. It should further be noted that the drawings are only
intended for schematically representing embodiments of the present
invention and not for showing detailed constructions thereof.
For instance, the step member 7 can be combined with a self-
deploying mechanism, such as e.g. a spring. Thus, when opening the
maintenance step 4c by pulling the step member 7 out of the casing
6, the stirrup unit 15 is automatically deployed by means of the
spring. Furthermore, fixation of the telescopic elements of the stirrup
unit 15 can be achieved by various different means, such as e.g.
described in US 5,586,628 A, US 2003/0038007 Al, DE 26 43 463 Al,
CA 02952490 2016-12-20
23
DE 70 06 082 U, US 3,612,563 A, US 3,892,429 A and DE 10 2012
013 612 Al.
I,
CA 02952490 2016-12-20
24
Reference List
1 rotary wing aircraft
la fuselage
lb tail boom
lc tail wing
id fin
le drive system accommodating region
lf aircraft outer surface
1 g board side wall resp. lateral shell
1h starboard side wall resp. lateral shell
2 aircraft doors and windows
3 maintenance traps
4 board side maintenance steps
4a upper board side maintenance step
4b middle board side maintenance step
4c lower board side maintenance step
5 aircraft emergency exits
6 casing
6a frame-like support structure
p
li
CA 02952490 2016-12-20
,
6b inner opening
6c overhang
6d receiving opening
6e casing slope
5 7 step member
7a step member covering plate
7b step member stepping plate
7c fixing elements
7d step member anti-slip means
10 8 step member locking device
8a lock bar
9 step member hinges
9a upper hinge
9b lower hinge
15 10a upper hinge clevis
10b lower hinge clevis
11a upper hinge arm
11 b lower hinge arm
12 hinge pins
1,
CA 02952490 2016-12-20
26
13 attachment point
14 retaining element
15 stirrup unit
15a stirrup upper section
15b stirrup middle section
15c stirrup lower section
15d hinge connecting portions
15e stepping area
15f anti-slip means
16 telescopic element securing pins
17 attachment rope or rod
17a attachment rope or rod fixation element
18 pivot pins
19 pin receiving openings
20 shim plates
