U.S. patent application number 13/533835 was filed with the patent office on 2013-12-26 for lightweight helicopter skid shoes.
This patent application is currently assigned to Bell Helicopter Textron Inc.. The applicant listed for this patent is William A. Amante, James M. McCollough. Invention is credited to William A. Amante, James M. McCollough.
Application Number | 20130341461 13/533835 |
Document ID | / |
Family ID | 46799012 |
Filed Date | 2013-12-26 |
United States Patent
Application |
20130341461 |
Kind Code |
A1 |
McCollough; James M. ; et
al. |
December 26, 2013 |
Lightweight Helicopter Skid Shoes
Abstract
A lightweight skid shoe assembly comprises a body of wear
resistant, non-metallic or partially metallic material; and a
structure coupling mechanism; wherein the body prevents
friction-related damage to the structure. Another lightweight skid
shoe assembly comprises a body of wear resistant, non-metallic or
partially metallic material selected from the group consisting of:
a polyamide or polyimide impregnated carbon fiber layup, a peek or
PEI injection mold with carbon fiber, compression molded carbon
fiber or fiberglass, a resin infusion with carbon fiber preform
fabric, a fiber reinforced thermoset, acetal resin, machined acetal
or thermoplastic, thermosetting plastic, or a metal-matrix
composite; wherein the body prevents friction-related damage to a
structure. Another lightweight skid shoe assembly comprises a body
of wear resistant, non-metallic or partially metallic material; and
a shear-bearing mechanism; wherein the shear-bearing mechanism
directs shear forces away from the body; and wherein the body
prevents friction-related damage to the structure.
Inventors: |
McCollough; James M.;
(Arlington, TX) ; Amante; William A.; (Grapevine,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
McCollough; James M.
Amante; William A. |
Arlington
Grapevine |
TX
TX |
US
US |
|
|
Assignee: |
Bell Helicopter Textron
Inc.
Fort Worth
TX
|
Family ID: |
46799012 |
Appl. No.: |
13/533835 |
Filed: |
June 26, 2012 |
Current U.S.
Class: |
244/108 |
Current CPC
Class: |
B64C 25/52 20130101;
B64C 2025/325 20130101 |
Class at
Publication: |
244/108 |
International
Class: |
B64C 25/52 20060101
B64C025/52 |
Claims
1. A lightweight skid shoe assembly, comprising: a body having one
or more layers of wear resistant, non-metallic or partially
metallic material; and a coupling mechanism for coupling the body
to a structure; wherein the body withstands shear forces when
frictionally engaging a contact surface; and wherein the body
substantially prevents friction-related damage to a surface of the
structure to which it is coupled.
2. The lightweight skid shoe assembly of claim 1, wherein the
material of at least one of the layers is selected from the group
consisting of: a polyamide impregnated carbon fiber layup, a
polyimide impregnated carbon fiber layup, a peek injection mold
with carbon fiber, a polyetherimide injection mold with carbon
fiber, compression molded carbon fiber, compression molded
fiberglass, a resin infusion with carbon fiber preform fabric, a
fiber reinforced thermoset, acetal resin, machined acetal, machined
thermoplastic, thermosetting plastic, or a metal-matrix
composite.
3. The lightweight skid shoe assembly of claim 1, wherein the
coupling mechanism comprises apertures in the body for receiving
coupling hardware.
4. The lightweight skid shoe assembly of claim 1, wherein the
coupling mechanism comprises coupling bolts.
5. The lightweight skid shoe assembly of claim 1, wherein the
coupling mechanism comprises coupling straps.
6. The lightweight skid shoe assembly of claim 1, further
comprising: a shear-bearing mechanism operable to direct a portion
of the shear forces away from the body when the body frictionally
engages the contact surface.
7. The lightweight skid shoe assembly of claim 6: wherein the
shear-bearing mechanism comprises a retainer having an opening; and
wherein the body is disposed within the retainer.
8. The lightweight skid shoe assembly of claim 7, wherein the depth
of the opening is less than the thickness of the body.
9. The lightweight skid shoe assembly of claim 7, wherein a portion
of the body extends through the opening.
10. The lightweight skid shoe assembly of claim 6: wherein the
shear-bearing mechanism comprises a recess in the structure; and
wherein the body is disposed within the recess.
11. The lightweight skid shoe assembly of claim 10, wherein a
portion of the body extends beyond the recess.
12. The lightweight skid shoe assembly of claim 10, wherein walls
of the recess are operable to direct a portion of the shear forces
away from the body when the body frictionally engages the contact
surface.
13. The lightweight skid shoe assembly of claim 1, wherein the body
further comprises a wear indicator for determining when the body
needs to be replaced.
14. The lightweight skid shoe assembly of claim 1, wherein the body
may be dispensed from a roll of body material.
15. A lightweight skid shoe assembly, comprising: a body having one
or more layers of wear resistant, non-metallic or partially
metallic material selected from the group consisting of: a
polyamide impregnated carbon fiber layup, a polyimide impregnated
carbon fiber layup, a peek injection mold with carbon fiber, a
polyetherimide injection mold with carbon fiber, compression molded
carbon fiber, compression molded fiberglass, a resin infusion with
carbon fiber preform fabric, a fiber reinforced thermoset, acetal
resin, machined acetal, machined thermoplastic, thermosetting
plastic, or a metal-matrix composite; wherein the body
substantially prevents friction-related damage to a surface of a
structure to which it is coupled when the body frictionally engages
a contact surface.
16. The lightweight skid shoe assembly of claim 15, wherein the
body further comprises a wear indicator for determining when the
body needs to be replaced.
17. The lightweight skid shoe assembly of claim 15, further
comprising: a coupling mechanism for coupling the body to the
structure.
18. The lightweight skid shoe assembly of claim 15, further
comprising: a retainer coupled to the structure; wherein the body
is disposed within the retainer; and wherein the retainer is
operable to direct a portion of shear forces away from the body
when the body frictionally engages the contact surface.
19. The lightweight skid shoe assembly of claim 15, further
comprising: a recess within the structure; wherein the body is
disposed within the recess; and wherein walls of the recess are
operable to direct a portion of shear forces away from the body
when the body frictionally engages the contact surface.
20. A lightweight skid shoe assembly, comprising: a body having one
or more layers of wear resistant, non-metallic or partially
metallic material; and a shear-bearing mechanism within which the
body is disposed; wherein the shear-bearing mechanism is operable
to direct a portion of shear forces away from the body when the
body frictionally engages a contact surface; and wherein the body
substantially prevents friction-related damage to a surface of the
structure to which it is coupled.
Description
FIELD OF THE DISCLOSURE
[0001] The present disclosure generally relates to a skid shoe
assembly, and more particularly, to a lightweight skid shoe
assembly that may protect a structure, such as a helicopter skid
tube, from friction-related damage.
BACKGROUND
[0002] Many helicopters feature skid-type landing gear, which
generally comprises an assembly of horizontal skid tubes connected
by support structure the fuselage of the helicopter. Skid tubes may
be damaged by repeated contact and friction with landing surfaces
during takeoffs, landing, and ground transport. Pads of
wear-resistant metal, known as skid shoes, are typically attached
to the skid tubes to protect them from damage. While they offer
effective protection, traditional skid shoes are relatively heavy,
which can reduce the usable load capability of a helicopter.
SUMMARY
[0003] Embodiments of the present disclosure generally provide
lightweight skid shoe assemblies for protecting the surface of a
structure from friction-related damage.
[0004] The present disclosure is directed to a lightweight skid
shoe assembly comprising a body having one or more layers of wear
resistant, non-metallic or partially metallic material; and
coupling mechanism for coupling the body to a structure; wherein
the body withstands shear forces when frictionally engaging a
contact surface; and wherein the body substantially prevents
friction-related damage to a surface of the structure to which it
is coupled. In various embodiments, the material of at least one of
the layers is selected from the group consisting of: a polyamide
impregnated carbon fiber layup, a polyimide impregnated carbon
fiber layup, a peek injection mold with carbon fiber, a
polyetherimide injection mold with carbon fiber, compression molded
carbon fiber, compression molded fiberglass, a resin infusion with
carbon fiber preform fabric, a fiber reinforced thermoset, acetal
resin, machined acetal, machined thermoplastic, thermosetting
plastic, or a metal-matrix composite.
[0005] In various embodiments, the coupling mechanism comprises
apertures in the body for receiving coupling hardware. In an
embodiment, the coupling mechanism comprises coupling bolts. In
another embodiment, the coupling mechanism comprises coupling
straps.
[0006] In various embodiments, lightweight skid shoe assembly
further comprises a shear-bearing mechanism operable to direct a
portion of the shear forces away from the body when the body
frictionally engages the contact surface. In an embodiment, the
shear-bearing mechanism comprises a retainer having an opening; and
the body is disposed within the retainer. In another embodiment,
the depth of the opening is less than the thickness of the body. In
yet another embodiment, a portion of the body extends through the
opening.
[0007] In an embodiment, the shear-bearing mechanism comprises a
recess in the structure; and the body is disposed within the
recess. In another embodiment, a portion of the body extends beyond
the recess. In yet another embodiment, walls of the recess are
operable to direct a portion of the shear forces away from the body
when the body frictionally engages the contact surface.
[0008] In an embodiment, the body further comprises a wear
indicator for determining when the body needs to be replaced. In
another embodiment, the body may be dispensed from a roll of body
material.
[0009] In another aspect, the present disclosure is directed to a
lightweight skid shoe assembly comprising a body having one or more
layers of wear resistant, non-metallic or partially metallic
material selected from the group consisting of: a polyamide
impregnated carbon fiber layup, a polyimide impregnated carbon
fiber layup, a peek injection mold with carbon fiber, a
polyetherimide injection mold with carbon fiber, compression molded
carbon fiber, compression molded fiberglass, a resin infusion with
carbon fiber preform fabric, a fiber reinforced thermoset, acetal
resin, machined acetal, machined thermoplastic, thermosetting
plastic, or a metal-matrix composite; wherein the body
substantially prevents friction-related damage to a surface of a
structure to which it is coupled when the body frictionally engages
a contact surface. In an embodiment, the body further comprises a
wear indicator for determining when the body needs to be
replaced.
[0010] In various embodiments, lightweight skid shoe assembly
further comprises a coupling mechanism for coupling the body to the
structure.
[0011] In an embodiment, lightweight skid shoe assembly further
comprises a retainer coupled to the structure; wherein the body is
disposed within the retainer; and wherein the retainer is operable
to direct a portion of shear forces away from the body when the
body frictionally engages the contact surface.
[0012] In an embodiment, lightweight skid shoe assembly further
comprises a recess within the structure; wherein the body is
disposed within the recess; and wherein walls of the recess are
operable to direct a portion of shear forces away from the body
when the body frictionally engages the contact surface.
[0013] In yet another aspect, the present disclosure is directed to
a lightweight skid shoe assembly comprising a body having one or
more layers of wear resistant, non-metallic or partially metallic
material; and a shear-bearing mechanism within which the body is
disposed; wherein the shear-bearing mechanism is operable to direct
a portion of shear forces away from the body when the body
frictionally engages a contact surface; and wherein the body
substantially prevents friction-related damage to a surface of the
structure to which it is coupled.
[0014] Other technical features may be readily apparent to one
skilled in the art from the following figures, descriptions and
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] For a more complete understanding of this disclosure,
reference is now made to the following description, taken in
conjunction with the accompanying drawings, in which:
[0016] FIG. 1 depicts a perspective view of a series of skid shoe
assemblies coupled to a helicopter skid tube according to an
embodiment of the present disclosure;
[0017] FIG. 2 depicts a perspective view of a representative
multi-layer skid shoe body according to an embodiment of the
present disclosure;
[0018] FIG. 3 depicts a perspective view of a skid shoe assembly
comprising bolts coupled to the protected structure of a helicopter
skid tube according to an embodiment of the present disclosure;
[0019] FIG. 4 depicts a perspective view of a skid shoe assembly
comprising straps coupled to the protected structure of a
helicopter skid tube according to an embodiment of the present
disclosure;
[0020] FIG. 5A depicts a bottom view of a skid shoe assembly
comprising a shear-bearing retainer coupled to the protected
structure of a helicopter skid tube according to an embodiment of
the present disclosure;
[0021] FIG. 5B depicts a side view of the skid shoe assembly of
FIG. 5A according to an embodiment of the present disclosure;
[0022] FIG. 6A depicts a bottom view of a skid shoe assembly
comprising a skid shoe body disposed in a shear-bearing recess
formed in a helicopter skid tube according to an embodiment of the
present disclosure; and
[0023] FIG. 6B depicts a side view of the skid shoe assembly of
FIG. 6A.
DETAILED DESCRIPTION
[0024] Embodiments of the present disclosure generally provide a
lightweight skid shoe assembly for use in a variety of applications
including, but not limited to, protecting helicopter skid landing
gear and other structures from friction-related damage. The skid
shoe assembly may be lighter than traditional skid shoe assemblies,
thereby reducing a helicopter's empty weight and increasing its
useful load. In various embodiments, lightweight skid shoe assembly
may be easier to periodically replace than traditional skid shoe
assemblies. In various embodiments, the skid shoe assembly may
comprise a skid shoe body of wear-resistant materials, all or a
portion of which having sacrificial wear properties, a
shear-bearing coupling mechanism to alleviate shear forces acting
on the skid shoe body, and/or a recess in a protected structure
within which the skid shoe body is disposed.
[0025] FIGS. 1-6B illustrate representative embodiments of skid
shoe assemblies 100, 150, 160, 170, 180 and parts thereof. It
should be understood that the components of skid shoe assemblies
100, 150, 160, 170, 180 and parts thereof shown in FIGS. 1-6B are
for illustrative purposes only, and that any other suitable
components or subcomponents may be used in conjunction with or in
lieu of the components comprising skid shoe assemblies 100, 150,
160, 170, 180 and the parts of skid shoe assemblies 100, 150, 160,
170, 180 described herein.
[0026] Referring now to FIG. 1, a representative skid shoe assembly
100 is shown coupled to a protected structure 110, such as a
helicopter skid tube 112. In one embodiment, a single skid shoe
assembly 100 may generally cover a portion of, or substantially the
entirety of, a protected surface 120 of the protected structure
110, such as the underside 114 of the helicopter skid tube 112, for
example. In another embodiment, a series of skid shoe assemblies
100 may cover a portion of, or substantially the entirety of, the
protected surface 120 of the protected structure 110. For example,
as depicted in FIG. 1, a series of skid shoe assemblies 100 may be
arranged in a spaced apart manner along the protected structure 110
to cover a portion of the protected surface 120, thereby resulting
in uncovered portions 122 of the protected surface 120 and covered
portions 124 of the protected surface covered by the skid shoe
assemblies 100.
[0027] The series of skid shoe assemblies 100 may further be
configured to minimize or prevent contact between the uncovered
portions 122 of the protected surface 120 and a contact surface
130, such as a helicopter landing pad, for example. As depicted in
FIG. 1, one or more skid shoe assemblies 100 may be configured to
protrude a suitable distance from the protected surface 120 to
create a gap 125 between the uncovered portions 122 of the
protected surface 120 and the contact surface 130.
[0028] The skid shoe assemblies 100 may vary in size, shape,
thickness, materials, and construction. Skid shoe assemblies 100
having larger exposed areas and/or more wear-resistant
constructions may be disposed on high-traffic or high-friction
protected surfaces 120 or portions thereof, while skid shoe
assemblies 100 having smaller exposed areas and/or less
wear-resistant constructions may be disposed on lower-traffic or
lower-friction protected surfaces 120 or portions thereof.
[0029] Some non-metallic constructions may offer less protection or
be less durable than metallic constructions in certain
applications. In a helicopter context, heavy-duty metallic skid
shoes may still be needed under rigorous operating conditions
involving numerous and/or hard landings, such as training or
certification testing. It is not uncommon for helicopters to touch
down and slide on a runway at speeds in excess of 60 knots during
engine failure simulations, for example. Under normal operating
conditions, however, operators often use medium-duty skid shoes to
save weight and boost useful load as hard landings and landings on
unprepared surfaces are far less common. Non-metallic skid shoe
constructions are well suited for such conditions, as they may
provide the requisite level of protection, while offering a lower
weight penalty and easier replacement. In the event of a hard
landing that exceeds the structural capabilities of the
non-metallic skid shoe assembly 100, an operator may be required to
replace the skid landing gear. Many operators would view this as an
acceptable cost of doing business given the relative infrequency of
such events.
[0030] Referring now to FIG. 2, the skid shoe assembly 100 may
comprise a skid shoe body 200 having one or more layers 215 of
lightweight, wear-resistant, non-metallic or partially metallic
materials that may include, but are not limited to, a polyamide
impregnated carbon fiber layup, a polyimide impregnated carbon
fiber layup, a peek or PEI injection mold with carbon fiber,
compression molded carbon fiber or fiberglass, a resin infusion
with carbon fiber preform fabric, a fiber reinforced thermoset,
acetal resin (such as DuPont.TM. Delrin.RTM.), machined acetal (or
any wear resistant and structurally robust thermoplastic or
thermosetting plastic), formed thermoplastics or thermosetting
plastic, a metal-matrix composite, or any other lightweight
non-metallic or partially metallic materials with sufficient
capability for wear. One having ordinary skill in the art will
recognize that skid shoe body may be comprised of any number of
suitable lightweight, wear-resistant, non-metallic or partially
metallic materials and constructions, and the present disclosure
should not be limited to only the examples provided herein. In
various embodiments, skid shoe body 200 may further comprise
materials and/or constructions that provide for structural
reinforcement. In one embodiment, skid shoe body 200 may comprise
injection-molded nylon with fiberglass or carbon fiber
reinforcement. In another embodiment, skid shoe body may comprise
compression molded carbon fiber or fiberglass with one or more
integral co-molded steel wear strips. All or a portion of skid shoe
body 200 may have sacrificial wear properties. In various
embodiments, one or more layers 215 of body 200 may be classified
as "sacrificial" layers, being comprised of any suitable
wear-resistant material such as those described in this paragraph
that may gradually wear away due to repeated frictional contact
with contact surface 130. In a helicopter application, wear rate
may be a function of the number of landings, any fore/aft or
lateral skidding during landings, and the surface properties of the
landing area. In various embodiments, body 200 may comprise one or
more layers 215 of lightweight, yet structurally robust material,
that may be suitable to withstand all or a portion of shear loads
occurring at the junction(s) of skid shoe body 200 with protected
structure 110. Skid shoe body 200 may further comprise coupling
points 300 that may be defined by flanges or apertures extending
from or disposed through body 200, respectively, for coupling the
layers 215 of the skid shoe body 200 together and/or for coupling
the skid shoe body 200 to the protected structure 110.
[0031] In various embodiments, body 200 may be manufactured such
that it may be disposed from a roll much like adhesive tape. A user
may unroll a desired amount of body material from the roll and cut
it to customized dimensions for coupling to the protected
structure. In an embodiment, an amount corresponding with a
dimension of the protected surface may be dispensed. In another
embodiment, smaller sections may be dispensed and spaced in any
suitable interval or pattern on the protected surface. A user may
find such an embodiment beneficial for reasons including, but not
limited to, less material waste, the ability to customize skid shoe
dimensions, flexibility to "patch" high wear areas, and reduced
cost from not having to buy custom-made skid shoes for one or more
applications. One having ordinary skill in the art will recognize
that body 200 may be manufactured any suitable manner and form, and
the present disclosure should not be limited to the specific
embodiments described herein.
[0032] FIGS. 3 and 4 each depict an embodiment of a skid shoe
assembly 150, 160 comprising a coupling mechanism 310 for coupling
the skid shoe body 200 to a protected structure 110, such as a
helicopter skid tube 112, to cover at least a portion of a
protected surface 120, such as the underside 114 of the helicopter
skid tube 112, for example. In various embodiments, coupling
mechanism 310 may react all or a portion of shear loads on the skid
shoe body 200. In an embodiment, coupling mechanism 310 may couple
a skid shoe body 200 to a skid tube 112 and may resist fore/aft
slippage of body 200 on skid tube 112 during a run-on landing. In
another embodiment, coupling mechanism 310 may resist lateral
slippage of body 200 on skid tube 112 that would otherwise be
caused by rotational movement of the skid tube 112 when flexing
(spreading) under the vertical landing load of the helicopter.
[0033] Referring now to FIG. 3, the coupling mechanism 310 of the
skid shoe assembly 150 comprises a bolt 312 or a series of bolts
312 to secure the skid shoe body 200 to the helicopter skid tube
112 at discrete coupling points 300. The bolts 312 project through
the skid shoe body 200 at coupling points 300 and into the
protected structure 110, thereby securing skid shoe 200 thereon and
covering a portion 124 of the protected surface 120. In an
embodiment, bolt 312 may have a tapered head for improved shear
reaction. During helicopter landings, as the helicopter skid tube
112 touches down, the skid shoe body 200 will make frictional,
engaging contact with the contact surface 130, while generally
preventing wearing engagement of the protected surface 120, 114
with the contact surface 130. With multiple helicopter landings,
the skid shoe body 200 will gradually wear away due to such
frictional engaging contact with the contact surface 130, and
eventually, layers 215 of the skid shoe body 200, or the entire
skid shoe body 200, will need to be replaced. The worn skid shoe
body 200 may be removed by releasing the bolts 302 at the discrete
contact points 300 that secure the skid shoe body 200 to the
protected structure 110, 112.
[0034] Referring now to FIG. 4, the coupling mechanism 310 of skid
shoe assembly 160 comprises a strap 314 or a series of straps 314
that extend from coupling point(s) 300a located near a first edge
210 of the skid shoe body 200, then wrap around the protected
structure 110, 112, and connect to corresponding coupling point(s)
300b located near a second opposing edge 212 of skid shoe body 200.
In an embodiment, straps 314 comprise band clamps. Similarly,
coupling mechanism 310 may comprise a collar (not shown) that may
enshroud all or a portion of skid shoe body 200 and protected
structure 110, thereby coupling them together and providing a
mechanism to react all or a portion of shear loads acting thereon.
In an embodiment, collar may be heat shrinked, bonded, or
mechanically fastened to protected structure 110. During helicopter
landings, as the helicopter skid tube 112 touches down, the skid
shoe body 200 will make frictional, engaging contact with the
contact surface 130, while generally preventing wearing engagement
of the protected surface 120, 114 with the contact surface 130.
With multiple helicopter landings, the skid shoe body 200 will
gradually wear away due to such frictional engaging contact with
the contact surface 130, and eventually, layers 215 of the skid
shoe body 200, or the entire skid shoe body 200, will need to be
replaced. The worn skid shoe body 200 may be removed by releasing
the straps 314 securing the skid shoe body 200 to the protected
surface 110, 112.
[0035] With respect to skid shoe assemblies 150, 160 shown in FIGS.
3 and 4, shear loads may be concentrated at the coupling points
300, 300a, 300b. As such, the skid shoe body 200 may have inherent
shear strength properties sufficient to withstand shear frictional
forces associated with engaging a contact surface 130 without
suffering damage or becoming dislodged. If necessary, skid shoe
body 200 may comprise reinforced materials or reinforcing
mechanisms (such as grommets, not shown) at coupling points 300,
300a, 300b. One having ordinary skill in the art will appreciate
that specific shear strength requirements are application
dependent, and will recognize a suitable construction for the skid
shoe body 200 and coupling mechanisms 310 described herein for a
given application.
[0036] FIGS. 5A and 5B depict a bottom plan view and a side
elevation view, respectively, of another embodiment of a skid shoe
assembly 170 comprising one or more shear-bearing mechanisms 400.
Shear-bearing mechanism 400 may comprise any mechanism suitable to
direct a significant portion of the shear stress on skid shoe
assembly 170 away from the skid shoe body 200 and distribute such
shear stress throughout the shear-bearing mechanism 400.
[0037] In an embodiment, the shear-bearing mechanism 400 comprises
one or more retainers 410 for coupling the skid shoe body 200 to a
protected surface 120, 114 of the protected structure 110, 112.
Retainer 410 may be constructed of any suitable non-metallic,
partially metallic, or metallic material and may be of any suitable
planform to cover a portion of, or substantially the entirety of,
skid shoe body 200. As best shown in FIG. 5A, retainer 410 may
comprise one or more openings 420 that may be substantially equal
to or smaller in dimension than skid shoe body 200. As best shown
in FIG. 5B, retainer 410 may further have a thickness substantially
equal to or less than the thickness of body 200. Retainer 410 may
wrap around skid shoe body 200 and at least partially surround the
protected structure 110, 112, thereby coupling the skid shoe body
200 to the protected structure 110, 112 and covering a portion 124
of the protected surface 120, 114. In an embodiment, a bolt 312 or
a series of bolts 312 may be used to secure the retainer 410 to the
protected structure 110, 112.
[0038] As best shown in FIG. 5B, retainer 410 may be oriented
relative to skid shoe body 200 such that a substantial portion of
skid shoe body 200 projects through each opening 420, resulting in
exposed portions 210 and unexposed portions 220 of skid shoe body
200. Such a configuration may result in the retainer 410 applying
shear support to the unexposed portions 220 of skid shoe body 200,
while allowing the exposed portions 210 of skid shoe body 200 to
engage a contact surface 130. One having ordinary skill in the art
will be capable of determining a suitable size of opening 420 in
retainer 410, as well as a suitable thickness of retainer 410,
based on the desired amount of shear support to be provided to the
unexposed portions 220 of skid shoe body 200 and the desired amount
of area for exposed portions 210 of skid shoe body 200.
Shear-bearing coupling mechanisms 400 may be used as the sole means
of coupling skid shoe body 200 to protected structure 110, 112, or
in addition to other coupling mechanisms 300.
[0039] During helicopter landings, as the helicopter skid tube 112
touches down, the lower surface 217 of the exposed portions 210 of
skid shoe body 200 will make frictional, engaging contact with the
contact surface 130, while generally preventing wearing engagement
of the protected surface 120, 114 with the contact surface 130.
Simultaneously, the retainer 410 will provide shear support to the
unexposed portions 220 of the skid shoe body 200 during such
landings.
[0040] With multiple helicopter landings, the exposed portions 210
of the skid shoe body 200 will gradually wear away due to such
frictional engaging contact with the contact surface 130, and
eventually, layers 215 of the skid shoe body 200, or the entire
skid shoe body 200, will need to be replaced. In various
embodiments, skid shoe body 200 may comprise a visual indicator to
indicate the degree of wear and tear. In one embodiment, body 200
may be imbedded with one or more colors at various depths to
indicate the degree of wear. In another embodiment, body 200
comprises layers 215 of different materials that may be visually
distinguished from each other. When "sacrificial" layers have worn
away, non-sacrificial will begin to show, indicating the need for
replacement. While wear may be visible on traditional metallic skid
shoes, it can be difficult to ascertain its remaining thickness
without removing it from the aircraft. If a maintainer waits too
long to replace a skid shoe, it may wear completely through in
certain areas, exposing the skid tube to friction-related damage.
Alternatively, it can be pricey to replace skid shoes too often.
Visible indication of wear, be it through some sort of layered
color band, exposure of a different material in the skid shoe body,
or any other suitable mechanism, is a benefit of embodiments of the
present disclosure.
[0041] The worn skid shoe body 200 may be removed by releasing the
bolts 312 securing the retainer 410 to the protected surface 110,
112 and then removing the skid shoe body 200 from the retainer 410.
Alternatively, layers 215 of the worn skid shoe body 200 comprising
the exposed portions 210 may be removed and replaced without
removing the retainer 410 by accessing such layers 215 through the
opening 420 via coupling points 300 on the skid shoe body 200, as
shown in FIG. 2. The abilities to accurately determine the
serviceability of the shoe 100 and easily replace them are benefits
of embodiments of the present disclosure as they are not generally
available with traditional fully-metallic skid shoes.
[0042] FIGS. 6A and 6B depict a bottom plan view and a side
elevation view, respectively, of another embodiment of a skid shoe
assembly 180 comprising one or more shear-bearing mechanisms 400.
In an embodiment, the shear-bearing mechanism 400 comprises a
recess 500 in the protected structure 110, 112 within which a skid
shoe body 200 may be disposed. As best shown in FIG. 6A, recess 500
may be substantially equal in planform shape and size to skid shoe
body 200, and as best shown in FIG. 6B, recess 500 may have a depth
substantially equal to or less than the thickness of skid shoe body
200. The skid shoe body 200 may be disposed within recess 500 and
coupled to one or more coupling surfaces 510 within the recess 500
by any coupling mechanism 310 suitable to secure skid shoe body 200
thereon. In an embodiment, a bolt 312 or a series of bolts 312 may
be used to secure the skid shoe body 200 to the coupling surfaces
510 at discrete coupling points 300. Similar to the shear-bearing
retainer 410 of skid shoe assembly 170, the coupling surfaces 510
and walls 520 of recess 500 may apply shear support to the
unexposed portions 220 of skid shoe body 200, and the depth of the
walls 520 may allow for exposed portions 210 of skid shoe body 200
to engage a contact surface 130. One having ordinary skill in the
art will be capable of determining a suitable size of recess 500,
as well as a suitable depth of walls 520, based on the desired
amount of shear support to be provided to the unexposed portions
220 of skid shoe body 200 and the desired amount of area for
exposed portions 210 of skid shoe body 200.
[0043] During helicopter landings, as the helicopter skid tube 112
touches down, the lower surface 217 of the exposed portions 210 of
skid shoe body 200 will make frictional, engaging contact with the
contact surface 130, while generally preventing wearing engagement
of the protected surface 120, 114 with the contact surface 130.
Simultaneously, the walls 520 of the recess 500 will provide shear
support to the unexposed portions 220 of the skid shoe body 200
during such landings. With multiple helicopter landings, the
exposed portions 210 of the skid shoe body 200 will gradually wear
away due to such frictional engaging contact with the contact
surface 130, and eventually, layers 215 of the skid shoe body 200,
or the entire skid shoe body 200, will need to be replaced. Layers
215 or the entire worn skid shoe body 200 may be removed by
releasing the bolts 312 securing the skid shoe body 200 to the
coupling surfaces 210 and then removing the layers 215 or the
entire skid shoe body 200 from the recess 500.
[0044] Skid shoe assembly 100 may further comprise a wear skin (not
shown) for protecting uncovered portions 122 of a protected surface
120. Wear skin may comprise a thin layer of any suitable
non-metallic wear-resistant material. Wear skin may offer scratch
protection from debris (rocks, gravel, sand, etc) on an unprepared
landing surface. In an embodiment, wear skin may be applied to
uncovered portions 122 exposed by gaps 125 between skid shoe bodies
200. In another embodiment, wear skin may be disposed from a roll
much like adhesive tape.
[0045] It may be advantageous to set forth definitions of certain
words and phrases used in this patent document. The term "couple"
and its derivatives refer to any direct or indirect communication
between two or more elements, whether or not those elements are in
physical contact with one another. The terms "include" and
"comprise," as well as derivatives thereof, mean inclusion without
limitation. The term "or" is inclusive, meaning and/or. The phrases
"associated with" and "associated therewith," as well as
derivatives thereof, may mean to include, be included within,
interconnect with, contain, be contained within, connect to or
with, couple to or with, be communicable with, cooperate with,
interleave, juxtapose, be proximate to, be bound to or with, have,
have a property of, or the like.
[0046] Although the present disclosure and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations can be made herein without departing
from the spirit and scope of the disclosure as defined by the
appended claims. Moreover, the scope of the present application is
not intended to be limited to the particular embodiments of the
process, machine, manufacture, composition of matter, means,
methods and steps described in the specification. As one of
ordinary skill in the art will readily appreciate from the
disclosure, processes, machines, manufacture, compositions of
matter, means, methods, or steps, presently existing or later to be
developed that perform substantially the same function or achieve
substantially the same result as the corresponding embodiments
described herein may be utilized according to the present
disclosure. Accordingly, the appended claims are intended to
include within their scope such processes, machines, manufacture,
compositions of matter, means, methods, or steps.
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