U.S. patent application number 15/139561 was filed with the patent office on 2021-02-04 for auxetic locking pin.
This patent application is currently assigned to Rolls-Royce Plc. The applicant listed for this patent is Rolls-Royce Plc. Invention is credited to Carl Carson, Miklos Gerendas, Ali Shanian.
Application Number | 20210033129 15/139561 |
Document ID | / |
Family ID | 1000005164011 |
Filed Date | 2021-02-04 |
United States Patent
Application |
20210033129 |
Kind Code |
A1 |
Gerendas; Miklos ; et
al. |
February 4, 2021 |
AUXETIC LOCKING PIN
Abstract
A method of inserting a pin in a bore of an article may include
first providing an article with a bore, the bore having an inside
diameter. The method may then include providing a pin having a
hollow body, the hollow body having a diameter with a profile with
a pattern of voids. The method may then include applying an axial
force on an end of the hollow body to cause the diameter of the pin
to reduce in size to a point where the diameter of the pin is less
than the inside diameter of the article. The method may further
include aligning the pin inside of the bore of the article, and
then removing the axial force on the end of the hollow body.
Inventors: |
Gerendas; Miklos; (Am
Meelensee, DE) ; Shanian; Ali; (Montreal, CA)
; Carson; Carl; (Montreal, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rolls-Royce Plc |
London |
|
GB |
|
|
Assignee: |
Rolls-Royce Plc
London
GB
|
Family ID: |
1000005164011 |
Appl. No.: |
15/139561 |
Filed: |
April 27, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14050293 |
Oct 9, 2013 |
9353783 |
|
|
15139561 |
|
|
|
|
61792487 |
Mar 15, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16B 1/0014 20130101;
B23P 11/02 20130101; F16B 2/241 20130101; Y10T 403/75 20150115;
F16B 19/02 20130101; Y10T 403/7047 20150115; Y10T 403/7061
20150115; F16B 19/004 20130101; F16B 2/243 20130101; Y10T 29/49872
20150115 |
International
Class: |
F16B 19/02 20060101
F16B019/02; B23P 11/02 20060101 B23P011/02; F16B 19/00 20060101
F16B019/00; F16B 1/00 20060101 F16B001/00 |
Claims
1.-16. (canceled)
17. A method of inserting a pin in a bore of an article comprising
the steps of: providing an article with a bore, the bore having an
inside diameter; providing a pin having a hollow body, the hollow
body having a diameter with a profile with a pattern of voids, the
hollow body having an end; applying an axial force on the end of
the hollow body to cause the diameter of the pin to reduce in size
to a point where the diameter of the pin is less than the inside
diameter of the article; aligning the pin inside of the bore of the
article; and removing the axial force on the end of the hollow
body.
18. The method as claimed in claim 17, wherein the step of removing
the axial force causes the diameter of the pin to increase.
19. The method as claimed in claim 17, further comprising the step
of providing a fixture, the fixture has a driver that applies the
axial force on the end of the hollow body.
20. The method as claimed in claim 17, wherein the pin is made by:
providing a sheet of metal, stamping a pattern of shapes into the
sheet of metal, and rolling a stamped sheet of metal into a
cylindrically shaped structure.
21. The method as claimed in claim 19, further comprising: loading
the article on to a shaft of the fixture; and loading the pin in to
the fixture, where an end of the shaft impinges upon an end of the
pin.
22. The method as claimed in claim 21, wherein the axial force is
applied by the shaft.
23. The method as claimed in claim 17, further comprising: applying
an axial force on the end of the hollow body to cause the diameter
of the pin to reduce in size to a point where the diameter of the
pin is less than the inside diameter of the article; and removing
the pin from inside of the bore of the article.
24. The method as claimed in claim 17, wherein the pattern of voids
includes axial ellipses and circumferential ellipses, the axial
ellipses each having a smaller short axis and larger long axis on
an inside diameter of the hollow body than on an outside diameter
of the hollow body, and the circumferential ellipses each having a
larger short axis and a shorter long axis on the inside diameter
than on the outside diameter.
25. The method as claimed in claim 17, wherein said pattern of
voids is distributed over an entire circumference of the hollow
body for an entire axial length of the hollow body.
26. The method as claimed in claim 21, further comprising: applying
an axial force on the end of the hollow body to cause the diameter
of the pin to reduce in size to a point where the diameter of the
pin is less than the inside diameter of the article; removing the
pin from inside of the bore of the article; and removing the pin
from the fixture.
27. A method comprising: loading an article having a bore onto a
shaft of a fixture; loading a pin into the fixture, the pin having
a hollow body, the hollow body having a diameter with a profile
with a pattern of voids; applying, by an end of the shaft, an axial
force on an end of the hollow body to cause the diameter of the pin
to reduce in size to a point where the diameter of the pin is less
than the inside diameter of the article; aligning the pin inside of
the bore of the article; and removing the axial force on the end of
the hollow body.
28. The method as claimed in claim 27, wherein the step of removing
the axial force causes the diameter of the pin to increase.
29. The method as claimed in claim 27, wherein the pin is made by:
providing a sheet of metal; stamping the pattern of voids into the
sheet of metal; and rolling a stamped sheet of metal into a
cylindrically shaped structure.
30. The method as claimed in claim 27, wherein the pattern of voids
includes axial ellipses and circumferential ellipses, the axial
ellipses each having a smaller short axis and larger long axis on
an inside diameter of the hollow body than on an outside diameter
of the hollow body, and the circumferential ellipses each having a
larger short axis and a shorter long axis on the inside diameter
than on the outside diameter.
31. The method as claimed in claim 27, wherein said pattern of
voids is distributed over an entire circumference of the hollow
body for an entire axial length of the hollow body.
32. The method as claimed in claim 27, further comprising: applying
an axial force on the end of the hollow body to cause the diameter
of the pin to reduce in size to a point where the diameter of the
pin is less than the inside diameter of the article; removing the
pin from inside of the bore of the article; and removing the pin
from the fixture.
33. An assembly of a pin and an article formed by the process
comprising the steps of: providing an article with a bore, the bore
having an inside diameter; providing a pin having a hollow body,
the hollow body having a diameter with a profile with a pattern of
voids, the hollow body having an end; applying an axial force on
the end of the hollow body to cause the diameter of the pin to
reduce in size to a point where the diameter of the pin is less
than the inside diameter of the article; aligning the pin inside of
the bore of the article; and removing the axial force on the end of
the hollow body.
34. The assembly as claimed in claim 33, wherein the pattern of
voids includes axial ellipses and circumferential ellipses, the
axial ellipses each having a smaller short axis and larger long
axis on an inside diameter of the hollow body than on an outside
diameter of the hollow body, and the circumferential ellipses each
having a larger short axis and a shorter long axis on the inside
diameter than on the outside diameter.
35. The assembly as claimed in claim 33, wherein said pattern of
voids is distributed over an entire circumference of the hollow
body for an entire axial length of the hollow body.
36. The assembly as claimed in claim 33, wherein the pin is made
by: providing a sheet of metal; stamping the pattern of voids into
the sheet of metal; and rolling a stamped sheet of metal into a
cylindrically shaped structure.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 14/050,293, filed Oct. 9, 2013, which claims priority to
U.S. Provisional Patent Application No. 61/792,487, filed Mar. 15,
2013, all of which are hereby incorporated by reference in their
entirety.
FIELD OF TECHNOLOGY
[0002] A mechanism for securing two members, and more particularly,
transformative periodic structures and tunable photonic crystals
that may be used as hollow, rolled, spring, or a solid pin.
BACKGROUND
[0003] Retaining structures such as pins are used to secure
multiple members together so that a combined pinned assembly may be
created. Sometimes the combined assembly is to be permanently held
together and sometimes it is desirable to disassemble the assembly
so that it can be serviced, rebuilt or otherwise repaired. Based
upon the design circumstances, it may be difficult to repair
certain pinned assemblies due to environmental or physical
constraints.
[0004] Pins may be constructed of various materials, including but
not limited to metal, polymers, rubber and wood. Such pins have
been utilized in numerous products and machinery throughout
industry and society. Many of the materials that have been utilized
to make pins and other retaining structures have been designed to
perform under certain predetermined environmental constraints.
However, certain environmental conditions are so severe that
traditional constructs of pins structures simply cannot operate
under such extreme conditions.
[0005] A pin typically has a longitudinal axis and radii that
define a part of the geometry of the pin. The geometry of the pin
traditionally has a solid construct which lends itself for use in
high shear conditions. Based upon the material used, the pin will
have varying compression, shear, tension and elastic
characteristics. Irrespective of the material used, virtually all
materials undergo a transverse contraction when stretched in one
direction and a transverse expansion when compressed. The magnitude
of this transverse deformation is governed by a material property
known as Poisson's ratio, Poisson's ratio is defined as the
transverse strain divided by the axial strain in the direction of
stretching force. Since ordinary materials contract laterally when
stretched and expand laterally when compressed. Poisson's ratio for
such materials is positive. Poisson's ratios, denoted by a Greek
nu, n, for various materials are approximately 0.5 for rubbers and
for soft biological tissues, 0.45 for lead, 0.33 for aluminum, 0.27
for common steels, 0.1 to 0.4 for cellular solids such as typical
polymer foams, and nearly zero for cork.
[0006] Negative Poisson's ratios are theoretically permissible but
have not been successfully observed in real materials.
Specifically, ire an isotropic material (a material which does not
have a preferred orientation) the allowable range of Poisson's
ratio is from -1.0 to +0.5, based on thermodynamic considerations
of strain energy in the theory of elasticity (1). It would be
helpful to provide a pin structure that exhibits negative Poisson's
ratio.
[0007] Repairing an assembly that utilizes a pin traditionally
requires the pin to be driven out of the aperture in which it
resides. This can be accomplished by using a driver to force the
pin out to the aperture. However, in some circumstances a
manufacturer may not want a consumer to repair such assemblies as
doing so may invalidate the warranty, or even impact the integrity
of the system in which the pinned assembly is being used. For
example, if a manufacturer makes a part and that part should only
be serviced by an approved repair technician, then it is difficult
to monitor circumstances when the consumer may have attempted to
repair the pinned assembly themselves. In some instances the
consumer may damage a product by taking the repair into their own
hands, As such, it would be helpful to provide a locking pin that
has features in place that make it difficult for consumers to
repair or take apart a manufactured structure, such as a pinned
assembly.
[0008] It would also be helpful to provide an improved pin like
structure that is made of a process where void configurations are
generated in the material directly in a stress free state, whereby
the pin like structure can then undergo a loaded condition
resulting in a negative Poisson's ratio behavior. Such process
could be used to insert a pin structure into a part, but later
allow the part to be serviced again by re-loading the pin structure
so as to permit the pin to be removed from the part without
damaging the part.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 illustrates a perspective view of a locking pin, in
an unloaded state;
[0010] FIG. 2. illustrates a perspective view of a locking pin, in
a loaded state;
[0011] FIGS. 3A-3C illustrate a front view of a sheet of material,
depicting a void structure at various strain levels;
[0012] FIGS. 4A-4C illustrate a front view of another sheet of
material, depicting an alternative void structure at various strain
levels;
[0013] FIG. 5. illustrates a graph depicting the Poisson's ratio
versus normal strain, for the exemplary locking pin;
[0014] FIG. 6. illustrates side view of a locking pin installed in
a fixture, and the pin is in an unloaded state;
[0015] FIG. 7. illustrates a side view of a locking pin installed
in a fixture, and the pin is under load in the axial direction;
[0016] FIG. 8. illustrates a side view of a locking pin, in a
loaded state and being inserted a bore of a structure;
[0017] FIG. 9. illustrates an alternative shape for the void
structure shown FIGS. 3A-3C, in which the void structures are in a
"double-T" configuration;
[0018] FIG. 10 illustrates a material having void structures in a
"double-T" configuration, as shown in FIG. 9, and where the
placement and configuration of the void structures allows the
material to exhibit auxetic properties with areas of minimal
stress; and
[0019] FIG. 11 illustrates a material having the configuration of
"double-T" void structures as shown in FIG. 10, showing the forces
acting on the material when compression is applied.
DETAILED DESCRIPTION
[0020] In an exemplary embodiment a novel locking pin structure is
presented. The pin exhibits a negative Poisson's ratio and is made
of a material and construct that reduces its diameter when an axial
force is exerted on the longitudinal axis. The material could be a
rubber, metal, or others, that easily undergoes shape changes.
Another embodiment presents an improved method of inserting an
auxetic locking pin into a bore of a structure. The pin may undergo
a shape change when axial forces are exerted on the ends of the
pin, thus causing the outside diameter of the pin to reduce so as
to provide a clearance for the pin to be inserted into the bore of
a part. Once the axial force is removed, the diameter of the pin
expands thusly engaging the bore of the part causing a locking
engagement between the pin and the part.
[0021] Another exemplary embodiment includes a locking pin that
could be made of a hollow structure with specific void structures
in its surface. The void shapes or structures could be generated in
the material directly while it is in a stress-free state,
equivalent to collapsed void shapes found in rubber under external
load in order to get negative Poisson's ratio behavior in metal
without collapsing a metallic structure in manufacturing. The
void's shapes could be generated in a thick-walled hollow cylinder
of the intended size of the pin or the pin can be rolled from sheet
metal, in which prior to rolling a void structure has been
generated. It will be appreciated that the concepts and void
structures that are shown may be employed in areas apart from pins,
including but not limited to, combustors, seals, blade tracks, or
any components whose functions include maintaining a pressure
differential or metering air flow.
[0022] FIG. 1 illustrates an auxetic locking pin 10 that is
substantially tubular in shape having a hollow core 12, a thickness
14, a length 16, an outer diameter 18, an inner diameter 20 and a
plurality of surface configurations or voids 22. The locking pin 10
may be made of rubber, metal, or other material, as is desired for
the particular application to which it may be employed. The locking
pin 10 is shown in a relaxed, unloaded state, in FIG. 1.
[0023] The surface configurations 22, as depicted in FIG. 1, are
shown primarily circular in configuration. In an alternative
arrangement, the surface configurations are in a "double-T" shape,
as shown in FIG. 9. In this configuration, the void configurations
have a slot with two ends, and a rounded arc disposed on each end
of the slot. It will be appreciated that other geometric
configurations can be employed.
[0024] The configurations 22 represent apertures that extend
through the thickness 14 of the pin 10. The outer diameter 18 of
the pin 10 has configurations that are, in one exemplary
embodiment, substantially circular shaped while the inside diameter
20 has a shape 26 that is oval in geometric configuration. The
configurations 22 were placed in the surface 24 of the outside
diameter 18 while the material forming the pin 10 was in a relaxed,
unloaded state. FIG. I illustrates a flat sheet of material 40
(FIGS. 3A-3C) having a width 16 that may be rolled and the ends
welded or otherwise fixed to form the tubular shaped-pin structure
assembly that is shown in FIG. 1.
[0025] An exemplary configuration 22 includes patterns that
consists of horizontal and. vertical ellipses arranged on
horizontal and vertical symmetry lines in a way that the lines are
equally spaced in both dimensions (also .DELTA.x=.DELTA.y). The
center of the ellipses are on the crossing point of the symmetry
lines, and vertical and horizontal slots alternate on the vertical
and horizontal symmetry lines and any vertical slots is surrounded
by horizontal slots along the lines (and vice versa) and the next
vertical slots are found on both diagonals. See FIGS. 3A-3C.
[0026] In an alternative arrangement, patterns of horizontal and
vertical "double-T" void configurations are disposed on horizontal
and vertical symmetry lines in a way that the lines are equally
spaced in both dimensions, as shown in FIG. 10. Similarly to the
configuration shown in FIGS. 3A-3C, the centers of the "double-T"
void configurations are on the crossing points of the symmetry
lines, and vertical and horizontal "double-T" void configurations
alternate on the vertical and horizontal symmetry lines. Any
vertical "double-T" void configuration is surrounded by horizontal
"double-T" void configurations along both the vertical and the
horizontal symmetry lines.
[0027] An ellipse pattern on the outside diameter 18 of the
cylindrical component is equivalent to the pattern on the sheet
(vertical=axial, horizontal=circumferential). But the ellipse shape
on the inside diameter 20 is different due to the different radius
of this surface. Axial ellipses have a smaller short axis than on
the outside but a larger long axis. Circumferential ellipses have a
larger short axis than on the outside but a shorter long axis.
[0028] The material structure illustrated in FIG. 11 exhibits
auxetic properties. FIG. 11 shows the distribution of the void
structures. As shown in FIG. 11, the void structures are in a
"double-T" configuration, but other configurations could be used.
The circular arrows in FIG. 11 illustrate the forces that act
within the material when a compressive force is applied. As can be
seen, the material will compress, not only in the direction of the
applied force, but also in a direction perpendicular to the applied
force.
[0029] Similarly to the material illustrated in FIG. 11, the pin 10
has an advantageous behavior of an appeared (macroscopic) negative
Poisson's ratio. The structure of the pin 10 can be made to
contract in lateral direction when it is put under axial
compression load, without the metal it is made from, having a
negative Poisson's ratio. The behavior is triggered by the void
structures 22, as illustrated in FIG. 11,
[0030] FIG. 2 illustrates the FIG. 1 auxetic locking pin 10 in a
loaded state 28. Loading the locking pin 10 can be effectuated by
applying an axial force 30 in the direction of inwardly pointing
arrows 36 which causes an inwardly depending force F to be exerted
on the distally opposed ends 19. The exemplary embodiment shown in
FIG. 2 shows an auxetic locking pin 10 having a hole configuration
22'' that is different than configuration 22 shown in FIG. 1. The
hole configuration 22'' is but one of many different void structure
configurations that could be employed.
[0031] As the axial force 30 is applied to the locking pin 10, the
geometric configuration or structure of the locking pin 10 reacts
negatively by causing the surface of the outer diameter 80 of the
pin 10 to move inwardly in the direction of arrows 36. Thus, an
inwardly depending force 30, causes the outer diameter 80 of
locking pin 10 to move inwardly in the direction of arrows 36. The
reduction of the outer diameter 80 extends uniformly the entire
length 16 of the pin 10. The greater the axial force 30 that
impinges upon the ends 19, the higher degree of inward defamation
of the diameter 80. They are somewhat directly proportional. The
hole configurations 22'' are voids in the pin structure that react
under pressure to cause a negative Poisson's ratio like performance
of the pin 10.
[0032] FIGS. 3A-3C illustrate a sample of base material 40 that
could be employed to manufacture the auxetic locking pin 10 shown
in FIG. 1. The material 40 could be comprised of a sheet of
material that had voids 22 stamped therein while the sheet was in
its relaxed state. The material could be rubber, foam, metal, or
some other material. The apertures or voids 22 that are shown in
the surface of the sheet of material 40, are formed via stamping,
or some other manufacturing process. After the voids 22 have been
placed into the sheet 40, the sheet could undergo a roll forming,
or some other process, in order to form the tubular shaped locking
pin structure 10 that is depicted in FIG. 1. Once the sheet has
been placed in its tubular-shaped configuration, any remaining seam
may be bonded, welded, or otherwise fixed so as to create a
seamless pin like construct.
[0033] FIGS. 3A-3C illustrate the sheet of material 40 having gone
through three different stages of stressed conditions. Each such
stage represents a potential event where the configurations or
voids 22 take on a slightly different configuration as a load is
applied to the pin 10. The first step depicts a sheet of material
40 when in an unstrained condition 42 where the sheet 40 of
material is primarily unloaded. This is when no axial force F has
been applied to the ends 19 of the pin 10.
[0034] Step 2 illustrates a stage 44 Where the sheet 40 of material
has been strained, thus causing the oval structure 22' to become
oblong along a vertical axis 46, while becoming narrowed and
shortened along the x axis 48. As the sheet 40 of material becomes
more stressed, that is a greater axial force 30 is applied, the
oval structures 22 become more disfigured, resulting in the locking
pin 10 transforming into a different geometric configuration. At
this step the diameter 80 of the pin 10 begins to reduce as the
auxetic structure permits a reduction in diameter as the force 30
is applied inwardly.
[0035] Finally, with continued reference to FIGS. 3A-3C, another
step 50 occurs as inwardly applied axial force 30 continues to be
exerted on the auxetic locking pin 10. At this step the sheet 40 of
material has its oval shaped structures 22'' taking on an even more
extreme oval geometric configuration where the x axis 48 continues
to be shortened, while the y axis 46 continues to elongate. This
process may continue until a maximum negative strain level is
reached, thus resulting in a minimum diameter 80 being obtained,
See FIG. 2.
[0036] FIG. 5 illustrates a strain graph 60 that plots the
Poisson's ratio 62 on the y axis, relative to the normal strain 64
on the x axis. This graph depicts the relationship of force 30
being applied to the auxetic pin 10. For example, with continued
reference to FIGS. 3A-3C and 5, at step 1 (42), the sheet 40 may
initially take on a slightly positive Poisson's ratio of
approximately 0.2. However, as an axial force 30 continues to be
applied to the auxetic pin 10, the sheet 40 begins to transform the
structure to have a negative Poisson's ratio, such as that depicted
at step 2 (44) where approximately a -0.1 Poisson's ratio is
depicted. This is represented by step 3 (44), of FIGS. 3A-3C. At
this step, the diameter 80 of the locking pin 10 begins to contract
in the direction of arrows 36.
[0037] Finally, as an axial force 30 is continued to be applied to
the end 19 of the locking pin 10, the diameter 80 continues to
contract. The void structures at this stage have an elongated
configuration 22'' as is shown in step 3 (50) (FIG. 3). By applying
the axial force 30 the pin 10 reduces its diameter which may be
helpful to load a locking pin 10 into a part.
[0038] FIGS. 4A-4C illustrate an alternative pattern arrangement
whereby a sheet 40 of material includes a plurality of holes or
voids 22 and its surface. The sheet 40 is shown in an unstressed
state at first step 42. It will be appreciated that other geometric
configurations 22, apart from that which is shown in FIGS. 3A-4C,
are contemplated.
[0039] With continued reference to FIGS. 4A-4C, at step 2 (44) the
pin 10 has had a force 30 applied to the end 19 of the pin. This
causes the geometric configuration 22' to deform as it contracts
along the longitudinal x axis 48, and expands along the y axis
46.
[0040] As force 30 continues to be exerted on the end 19 of the pin
10, the sheet 40 of material continues to have its void structures
deform. This is shown in step 3 (50) where the material 40 is
stressed even further, and the geometric configurations 22'' have
been further transfigured where the oval shaped openings continue
to contract along the x axis 48 and elongate along the y axis
46,
[0041] It will be appreciated that the auxetic locking pin 10 as
illustrated in FIGS. 1. and 2, can have various thicknesses 14,
lengths 16, outside diameters 18, or inside diameters 20. Each of
which may employ an auxetic structure that is operable to have its
structure operate such that when a force is applied on an end 19 of
the pin 10, the diameter 18 contracts, thus allowing the auxetic
pin 10 to be loaded into another structure. Applications for this
unique concept can be used in industries where it desirable to
insert a pin into a boar of an article,
[0042] An exemplary Method of manufacturing an auxetic locking pin
10 will be presented. First a sheet 40 of material is provided
having a thickness 14 and a length 16. It may be made of metal,
rubber or other material. Next, while the sheet remains in a
relaxed state, apertures 22 are stamped or otherwise placed through
the thickness 14 of the material 40. One exemplary pattern is to
have alternating shapes along the x axis. One such non-limiting
example is to provide an oval shaped pattern where ovals are placed
in alternating patterns, such as that shown in FIGS. 3A-3C. Other
shapes or void structures are contemplated, including, but not
limited to, S-shaped, hook-shaped, J-shaped, and
dumbbell-shaped.
[0043] The next step is to roll the sheet 40 of material into a
tubular shape as shown in FIG. 1. This step creates a pin 10 that
has a bore 20 that extends the axial length 16 of the pin 10. A
seam may remain that can be bonded, welded or affixed via other
means. Other finishing steps may be employed to complete the
exterior surface of the pin. The pin 10 is now ready to be inserted
in a part.
[0044] FIGS. 6-8 depict one possible methodology that could be
employed for installing an auxetic locking pin 10 into a part 70.
The part 70 could be a device, article, or other structure that
needs a pin, barring, shaft, or the like inserted within the part
70. The part 70 may have a bore 72 that extends the axial length of
the part 70. A fixture or tool 74 may be provided to enhance the
process of installing a locking pin 10 into the part 70. FIG. 6
illustrates a first step in this process where the part 70 has been
loaded onto the shaft 76 of the tool 74. Once loaded, the part 70
is provided with an inside diameter 78 which is operable to receive
a locking pin 10. The locking pin 10 is shown loaded into the
fixture 74 where the end of the shaft 76 impinges upon an end 19 of
the locking pin 10. The locking pin at this stage has a diameter
18, which is unloaded.
[0045] FIG. 7 illustrates a force 30 being applied by the shaft 76
which results in a load being applied to the locking pin 10. At
this step the diameter 18 of the locking pin 10 begins to contract
to where it has a new diameter 80. The diameter 80 is smaller than
the diameter 18. As the force 30 continues to impinge upon the end
19 of the locking pin 10, the diameter 80 continues to decrease.
This continues until the diameter 80 is less than the inside
diameter 72, of the part 70. It would be helpful to provide a
diameter 80 that is sufficiently less than the diameter 78 of the
part 70, so as to allow a clearance therebetween.
[0046] FIG. 8 illustrates the pin 10 with its diameter 80 held
constant while the part 70 is slid axially in the direction of
arrow 82 (FIG. 7). The force 30 continues to be maintained on the
locking pin 10, during this step. The part 70 is slid in the
direction of arrow 82 until it reaches a point where the pin 10 is
centrally located within the bore 72 of the part 70.
[0047] Once the pin 10 has been fully inserted to the bore 72 of
the part 70, the shaft 76 of the fixture 74 is retracted in the
direction opposite of arrow 82. This allows the locking pin 10 to
relax and revert back to its larger diameter 18, or a size similar
thereto. Once the locking pin 10 reverts back towards its diameter
18, it becomes compressed with the bore 72, thus causing an
interference fit between the outer diameter 18 of the locking pin
10, and the bore 72 of the part 70. This interference fit creates a
locking engagement, thus firmly securing the pin 10 relative to the
part 70. Due to the larger overlap with the bore, the pin is more
securely locked in place. The additional edges 24 from the void
structure 22 lead to an additional "keying" with the bore 72. This
creates a locking engagement between the pin 10 and the part 70.
The locking engagement can be unlocked by reversing the
aforementioned steps. The pin 10 does not get loose due to external
load or vibrations.
[0048] The reverse steps may be employed in order to remove the
locking pin 10, from the part 70. A force 30 could be applied until
the structure of the locking pin 10 begins to transform, thus
causing the diameter 18 to decrease. Once the diameter sufficiently
decreases, it has a new diameter 80 which results in a clearance
between outer diameter 80 and the bore 72 of the part 70. The pin
10 can then be removed from the part 70.
[0049] With reference to FIG. 7, the part 70 has been separated
from the pin 10. The pin 10 may be removed from the fixture 74,
thus allowing the part 70 to be rebuilt. Likewise, in the event the
pin 10 needs to be serviced, the aforementioned steps may be
employed to provide a new, or refurbished, pin 10 into a part 70.
Thus, the present method and structure provides for a serviceable
part 70 where a new or refurbished pin 10 can be inserted into the
part 70. The present embodiment may be employed in other
applications, beyond that disclosed herein, where it is desirable
to provide a locking pin 10, or the like, into a bore of a
structure.
[0050] One of the features of an embodiment disclosed herein is
that an untrained person, who does not know about the specific
properties of the pin 10, cannot remove the pin 10 without
significant damage to the bore 72, which can be checked for by an
OEM during overhaul. If authorized personnel needs to remove the
pin 10, then they can apply the process mentioned above to first
compress the pin 10 and then while in the compressed state, slide
the pin 10 out without any damage to the bore 72. This specific
property allows the OEM to discover unauthorized manipulation
(witness pin), or the OEM can use the pin at a vibration level not
bearable for conventional pins in the past.
[0051] It will be appreciated that the aforementioned method and
devices may be modified to have some components and steps removed,
or may have additional components and steps added, all of which are
deemed to be within the spirit of the present disclosure. Even
though the present disclosure has been described in detail with
reference to specific embodiments, it will be appreciated that the
various modification and changes can be made to these embodiments
without departing from the scope of the present disclosure as set
forth in the claims. The specification and the drawings are to be
regarded as an illustrative thought instead of merely restrictive
thought.
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