U.S. patent application number 16/008724 was filed with the patent office on 2018-10-18 for personal escape device with eddy current braking.
The applicant listed for this patent is Bailout, LLC. Invention is credited to James R. Hendershot, Patrick Thomas Henke, Benjamin T. Krupp, Troy S. Owens, Michael Allen Ragsdale.
Application Number | 20180296860 16/008724 |
Document ID | / |
Family ID | 60326195 |
Filed Date | 2018-10-18 |
United States Patent
Application |
20180296860 |
Kind Code |
A1 |
Krupp; Benjamin T. ; et
al. |
October 18, 2018 |
PERSONAL ESCAPE DEVICE WITH EDDY CURRENT BRAKING
Abstract
A personal escape device includes a main housing, a shaft, a
magnet housing, and a plurality of magnets. The shaft is rotatably
coupled with the main housing and is rotatable about a rotational
axis. The magnet housing is positioned in the main housing and is
coupled with the shaft such that the magnet housing rotates
together with the shaft. The plurality of magnets is coupled with
the magnet housing such that the plurality of magnets rotates
together with the magnet housing. The stator assembly is coupled
with the main housing and surrounds the magnet housing. The stator
assembly and the magnet housing are radially spaced from each other
to define an air gap therebetween.
Inventors: |
Krupp; Benjamin T.;
(Wyoming, OH) ; Ragsdale; Michael Allen;
(Cincinnati, OH) ; Henke; Patrick Thomas;
(Hamilton, OH) ; Hendershot; James R.;
(Louisville, KY) ; Owens; Troy S.; (Cincinnati,
OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bailout, LLC |
Louisville |
KY |
US |
|
|
Family ID: |
60326195 |
Appl. No.: |
16/008724 |
Filed: |
June 14, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15600025 |
May 19, 2017 |
10022570 |
|
|
16008724 |
|
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|
|
62339468 |
May 20, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A62B 1/08 20130101; H02P
3/04 20130101; H02K 49/046 20130101; H02K 7/104 20130101; H02K
7/1004 20130101; H02K 16/005 20130101; H02K 49/043 20130101 |
International
Class: |
A62B 1/08 20060101
A62B001/08; H02K 7/104 20060101 H02K007/104 |
Claims
1. A personal escape device comprising: a main housing; a shaft
rotatably coupled with the main housing and rotatable about a
rotational axis; a magnet housing positioned in the main housing
and coupled with the shaft such that the magnet housing rotates
together with the shaft; a plurality of magnets coupled with the
magnet housing such that the plurality of magnets rotates together
with the magnet housing; a stator assembly coupled with the main
housing and surrounding the magnet housing, the stator assembly and
magnet housing being radially spaced from each other to define an
air gap therebetween, wherein: each magnet has a flux density; at
least a portion of the magnet housing is interposed between each
magnet and an adjacent magnet of the plurality of magnets; and the
portion of the magnet housing that is interposed between each
magnet and an adjacent magnet of the plurality of magnets is
configured to transmit substantially the entirety of the flux
density from each magnet to the stator.
2. The personal escape device of claim 1 wherein the magnet housing
comprises a hub and a rotor that are each formed of a metal and
cooperate to retain a plurality of magnets.
3. The personal escape device of claim 2 wherein the hub is formed
of a non-ferrous material.
4. The personal escape device of claim 1 wherein the stator
assembly comprises a stator and a back iron, the back iron being
sandwiched between the stator and the main housing.
5. The personal escape device of claim 4 wherein the stator is
formed of a non-ferrous material and the back iron is formed of a
ferrous material.
6. The personal escape device of claim 1 wherein the plurality of
magnets comprise eight magnets.
7. The personal escape device of claim 1 further comprising: a
pulley attached to the shaft and comprising a pair of disc members
that are coupled together and cooperate with each other to define a
groove; and a cord disposed in the groove and only partially wound
upon the disc members; wherein rotation of the disc members
facilitates dispensation of a portion of the cord from the disc
members.
8. The personal escape device of claim 1 wherein: the magnet
housing comprises a hub and a rotor that are each formed of a metal
and cooperate to retain a plurality of magnets; and the stator
assembly comprises a stator and a back iron, the back iron being
sandwiched between the stator and the main housing.
9. The personal escape device of claim 8 wherein: the hub is formed
of a non-ferrous material; the stator is formed of a non-ferrous
material; and the back iron is formed of a ferrous material.
10. A personal escape device comprising: a main housing; a shaft
rotatably coupled with the main housing and rotatable about a
rotational axis; a magnet housing positioned in the housing and
coupled with the shaft such that the magnet housing rotates
together with the shaft; a plurality of magnets coupled with the
magnet housing such that the plurality of magnets rotate together
with the magnet housing; a stator assembly coupled with the main
housing and surrounding the magnet housing, the stator assembly and
magnet housing being radially spaced from each other to define an
air gap therebetween, wherein: each magnet of the plurality of
magnets has an axis of polarization; and each magnet of the
plurality is arranged such that the axis of polarization is
oriented tangentially with respect to the axis of rotation of the
shaft.
11. The personal escape device of claim 10 wherein the magnet
housing comprises a hub and a rotor that are each formed of a metal
and cooperate to retain a plurality of magnets.
12. The personal escape device of claim 11 wherein the hub is
formed of a non-ferrous material.
13. The personal escape device of claim 10 wherein the stator
assembly comprises a stator and a back iron, the back iron being
sandwiched between the stator and the main housing.
14. The personal escape device of claim 13 wherein the stator is
formed of a non-ferrous material and electrically conductive back
iron is formed of a ferrous material.
15. The personal escape device of claim 10 wherein at least a
portion of the magnet housing is interposed between each magnet and
an adjacent magnet of the plurality of magnets.
16. The personal escape device of claim 10 further comprising: a
pulley attached to the shaft and comprising a pair of disc members
that are coupled together and cooperate with each other to define a
groove; and a cord disposed in the groove and only partially wound
upon the disc members; wherein rotation of the disc members
facilitates dispensation of a portion of the cord from the disc
members.
17. A personal escape device comprising: a main housing; a shaft
rotatably coupled with the main housing and rotatable about a
rotational axis; a magnet housing positioned in the housing and
coupled with the shaft such that the magnet housing rotates
together with the shaft; a plurality of magnets coupled with the
magnet housing such that the plurality of magnets rotates together
with the magnet housing; a stator assembly coupled with the main
housing and surrounding the magnet housing, the stator assembly and
magnet housing being radially spaced from each other to define an
air gap therebetween; a pulley attached to the shaft; and a cord
routed at least partially around the pulley, wherein rotation of
the pulley facilitates dispensation of a portion of the cord from
the pulley, wherein: each magnet of the plurality of magnets has an
axis of polarization; each magnet of the plurality is arranged such
that the axis of polarization is oriented tangentially with respect
to the axis of rotation of the shaft; and at least a portion of the
magnet housing is interposed between each magnet and an adjacent
magnet of the plurality of magnets.
18. The personal escape device of claim 17 wherein: the magnet
housing comprises a hub and a rotor that are each formed of a metal
and cooperate to retain a plurality of magnets; and the stator
assembly comprises a stator and a back iron, the back iron being
sandwiched between the stator and the main housing.
19. The personal escape device of claim 18 wherein: the hub is
formed of a non-ferrous material; the stator is formed of a
non-ferrous material; and the back iron is formed of a ferrous
material.
20. The personal escape device of claim 19 wherein the plurality of
magnets comprises eight magnets.
Description
REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 15/600,025, entitled Personal Escape Device
with Eddy Current Braking, filed May 19, 2017 which claims priority
of U.S. provisional patent application Ser. No. 62/339,468,
entitled Personal Escape Device with Eddy Current Braking, filed
May 20, 2016, and hereby incorporates these applications by
reference herein in their entirety.
BACKGROUND
[0002] Fires and other emergencies can occur in buildings and other
structures that have occupants trapped at high elevations. In some
emergency situations, conventional paths of egress, such as
interior stairwells or fire escapes become blocked with fire or
smoke, or are otherwise overloaded with evacuating occupants,
thereby impeding the ability of other occupants to exit the
structure in a timely fashion. Further, other occupants may not be
able to use certain paths of egress due to physical impairments. In
such cases, occupants that cannot exit the structure are forced to
wait for rescue. Thus, there is a need for a reliable device for
enabling the controlled descent of persons of a range of ages,
weights, and abilities from high elevations during emergency
situations.
SUMMARY
[0003] In accordance with one embodiment, a personal escape device
comprises a main housing, a shaft, a magnet housing, a plurality of
magnets, and a stator. The shaft is rotatably coupled with the main
housing and is rotatable about a rotational axis. The magnet
housing is positioned in the housing and is coupled with the shaft
such that the magnet housing rotates together with the shaft. The
plurality of magnets is coupled with the magnet housing such that
the plurality of magnets rotates together with the magnet housing.
The stator assembly is coupled with the main housing and surrounds
the magnet housing. The stator assembly and magnet housing are
radially spaced from each other to define an air gap therebetween.
Each magnet has a flux density. At least a portion of the magnet
housing is interposed between each magnet and an adjacent magnet of
the plurality of magnets. The portion of the magnet housing that is
interposed between each magnet and an adjacent magnet of the
plurality of magnets is configured to transmit substantially the
entirety of the flux density from each magnet to the stator
[0004] A personal escape device comprises a main housing, a shaft,
a magnet housing, a plurality of magnets, and a stator assembly.
The shaft is rotatably coupled with the main housing and is
rotatable about a rotational axis. The magnet housing is positioned
in the housing and is coupled with the shaft such that the magnet
housing rotates together with the shaft. The plurality of magnets
is coupled with the magnet housing such that the plurality of
magnets rotates together with the magnet housing. The stator
assembly is coupled with the main housing and surrounds the magnet
housing. The stator assembly and magnet housing are radially spaced
from each other to define an air gap therebetween. Each magnet of
the plurality of magnets has an axis of polarization. Each magnet
of the plurality is arranged such that the axis of polarization is
oriented tangentially with respect to the axis of rotation of the
shaft.
[0005] A personal escape device comprises a main housing, a shaft,
a magnet housing, a plurality of magnets, a stator assembly, a
pulley, and a cord. The shaft is rotatably coupled with the main
housing and is rotatable about a rotational axis. The magnet
housing is positioned in the housing and is coupled with the shaft
such that the magnet housing rotates together with the shaft. A
plurality of magnets is coupled with the magnet housing such that
the plurality of magnets rotates together with the magnet housing.
The stator assembly is coupled with the main housing and surrounds
the magnet housing. The stator assembly and magnet housing are
radially spaced from each other to define an air gap therebetween.
The pulley is attached to the shaft. The cord is routed at least
partially around the pulley. Rotation of the pulley facilitates
dispensation of a portion of the cord from the pulley. Each magnet
of the plurality of magnets has an axis of polarization. Each
magnet of the plurality is arranged such that the axis of
polarization is oriented tangentially with respect to the axis of
rotation of the shaft. At least a portion of the magnet housing is
interposed between each magnet and an adjacent magnet of the
plurality of magnets.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The present disclosure will be more readily understood from
a detailed description of some example embodiments taken in
conjunction with the following figures:
[0007] FIG. 1 depicts a cross-sectional view of a personal escape
device taken along the line 1-1 in FIG. 2, in accordance with one
non-limiting embodiment.
[0008] FIG. 2 depicts a side view of the personal escape device of
FIG. 1.
[0009] FIG. 3 depicts an enlarged cross-sectional view of the
encircled portion of FIG. 1 depicting a lateral end of the personal
escape device of FIG. 1.
[0010] FIG. 4 is an exploded view of FIG. 3.
[0011] FIG. 5 depicts a cross-sectional view taken along the line
5-5 in FIG. 2.
[0012] FIG. 6 depicts an example arrangement of magnets that are
coupled to a magnet housing.
[0013] FIG. 7 depicts an example line feed housing that can be
associated with a personal escape device.
[0014] FIG. 8 depicts another embodiment of a line feed
housing.
[0015] FIG. 9 depicts a cross-sectional view of an example braking
mechanism in accordance with one non-limiting embodiment.
[0016] FIGS. 10a-10b depict an example routing clip for assisting
with the placement of the protective channel relative to a
user.
[0017] FIG. 11 is a cross-sectional view taken along the line 11-11
in FIG. 15, in accordance with an alternative embodiment.
[0018] FIG. 12 is a cross-sectional view taken along the line 12-12
in FIG. 15.
[0019] FIG. 13 is a cross-sectional view depicting a stator
assembly of the personal escape device of FIG. 11, with certain
components removed for clarity of illustration.
[0020] FIG. 14 is a cross-sectional view taken along the line 14-14
in FIG. 15, with certain components removed for clarity of
illustration.
[0021] FIG. 15 is a cross sectional view depicting the personal
escape device of FIG. 11.
[0022] FIG. 16 is a cross sectional view depicting a magnetic
housing depicting the personal escape device of FIG. 11.
[0023] FIG. 17 is a perspective view depicting a disc member of the
personal escape device of FIG. 11.
[0024] FIG. 18 is a perspective view depicting a pair of the disc
members of FIG. 17.
[0025] FIG. 19 is a side view of the pair depicting the disc
members of FIG. 17.
[0026] FIG. 20 is a perspective view depicting a pulley of the
personal escape device of FIG. 11 with certain components removed
for clarity of illustration.
[0027] FIG. 21 is an upper view depicting the pulley of FIG.
20.
[0028] FIG. 22 is a plot depicting the results of testing of four
different prototype personal escape devices.
DETAILED DESCRIPTION
[0029] Various non-limiting embodiments of the present disclosure
will now be described to provide an overall understanding of the
principles of the structure, function, and use of the apparatuses,
systems, methods, and processes disclosed herein. One or more
examples of these non-limiting embodiments are illustrated in the
accompanying drawings. Those of ordinary skill in the art will
understand that systems and methods specifically described herein
and illustrated in the accompanying drawings are non-limiting
embodiments. The features illustrated or described in connection
with one non-limiting embodiment may be combined with the features
of other non-limiting embodiments. Such modifications and
variations are intended to be included within the scope of the
present disclosure.
[0030] Reference throughout the specification to "various
embodiments", "some embodiments", "one embodiment", "some example
embodiments", "one example embodiment", or "an embodiment" means
that a particular feature, structure, or characteristic described
in connection with any embodiment is included in at least one
embodiment. Thus, appearances of the phrases "in various
embodiments", "in some embodiments", "in one embodiment", "some
example embodiments", "one example embodiment", or "in an
embodiment" in places throughout the specification are not
necessarily all referring to the same embodiment. Furthermore, the
particular features, structures or characteristics may be combined
in any suitable manner in one or more embodiments.
[0031] Personal escape devices in accordance with the present
disclosure can be used by any of a variety of users, such as men,
women, children, and physically disabled persons, to descend in a
controlled and secure manner from structures. Example structures
can include, without limitation, office buildings, homes, bridges,
among other types of equipment (i.e., cranes, window washing
equipment, and the like). Other example uses of the personal escape
devices can include, for example, a high rescue kit (thereby
avoiding large equipment), seat belts or other devices that resist
occupant movement during a crash (e.g., in a school bus), deep
space evacuation, a self-belay device for climbing, lowering
lifeboats from a cruise ship, retrofit of an existing winch,
lowering heavy articles (e.g., a piano) from above ground (e.g., an
apartment), exercise training equipment (e.g., replacing resistance
band training), hospital patent recovery (e.g., traction or can
safely lower suspended patient from ceiling to ground), escape
device that is easily mountable to a window or other egress point
for home use, climbing equipment, riggers, helicopter deployment
(e.g., replacing fast rope), fire rescue, military building
clearing, drone escape (e.g., deployment of a drone that can anchor
itself to a structure and deliver a personal escape device to a
trapped individual), window washing, high rise tower maintenance,
windmill maintenance, evacuation for inoperable ski lifts, or the
like.
[0032] The personal escape device can be sized to be mobile and
easily handled by its user. The device can be anchored in a variety
of different positions and elevations, thereby giving users
flexibility and ease of use. While being used during a descent, the
user of the personal escape device can descend hands-free in a
controlled manner. In some embodiments, a user-controlled braking
mechanism is provided to allow the user to optionally come to a
complete stop.
[0033] A personal escape device in accordance with the present
disclosure can include a housing within which a spool is rotatably
mounted. The primary spool can extend along and rotate about a
central axis. A personal escape device can further include an
elongated cord that is wound around the spool, having its proximal
end affixed to the spool and the distal end extending through a
port in the housing. The cord can be constructed from any suitable
material, or combination of materials, such as wire rope, synthetic
rope, core and sheath rope, and so forth. An anchor assembly can
extend from, or otherwise be coupled to, the distal end of the
cord. The anchor assembly can allow for the distal end to be
coupled to a bracing object, such as a door, a door frame, a
structural beam or pillar, or other secure object of a structure.
Such coupling to the bracing object can be temporary (i.e.,
attached to the bracing object at the time of use) or permanently
or semi-permanently coupled to the bracing object.
[0034] Personal escape devices in accordance with the present
disclosure can include an unwind control assembly, which generally
controls the rate at which the cord exits from the housing during a
descent. Such an unwind control assembly can utilize eddy current
braking to control or regulate the speed of the spool during an
unwinding event. As described in more detail below, one or more
magnets can be coupled to the spool and arranged in a radial
fashion, such that rotation of the spool rotates the magnets about
the central axis. As the magnets rotate within a ferrous and/or
non-ferrous ring, eddy currents are created. The eddy currents, in
turn, yield torque values to provide a braking force to the spool
and slow the unwinding of the cord.
[0035] A device in accordance with the present disclosure can be
employed by a user to escape from a structure in times of
emergencies, or for any other suitable use. To escape from a
building, for example, the anchor assembly is affixed to a
structurally secure object or other type of connection point of the
building. The user can then open or break a window or other type of
opening or egress point. The user, once attached to the personal
escape device (i.e., via a harness, net, platform, pack, or other
assembly), exits through the opening. In response to the
gravity-induced force on the distal end of the cord, the cord exits
through the port in a controlled manner and the spool unwinds. As
the spool rotates, the magnets rotate within the ferrous and/or
non-ferrous ring. Eddy current braking impedes the rotation of the
spool to permit the spool to rotate at a controlled rate, thereby
allowing the user coupled to the spool to descend at a controlled
rate. The controlled rate can vary, but in some embodiments the
descent rate is less than about 1 m/s. In some embodiments, the
descent rate is less than about 2 m/s. In some embodiments, the
descent rate is less than about 3 m/s. In some embodiments, the
descent rate is less than about 4 m/s. As described in more detail
below, in addition to the eddy current brake system, other types of
brake systems can be included, such as hand-operated braking
systems, in order to provide the user with additional means for
controlling the rate of descent and/or stopping the descent.
[0036] FIG. 1 depicts a cross-sectional view of an example personal
escape device 50 in accordance with one non-limiting embodiment.
FIG. 2 depicts a side view of the personal escape device of FIG. 1.
Referring to FIGS. 1-2, the personal escape device 50 has a housing
1 that can be manufactured from substantially rigid, formable or
moldable materials, such as fiberglass, plastics, rigid metals, or
other suitable materials. The housing material can be of sufficient
strength to withstand the forces applied by the weight of the
payload (i.e., the user) during deployment. Payout rollers 9 can be
positioned within the housing 1 proximate to a payout port 11. In
some embodiments, the personal escape device 50 also includes a
protective channel 10 positioned proximate to the payout port
11.
[0037] A shaft 4 is disposed within the housing 1 and is rotatable
about a central axis. A cord 8 is wound around the shaft 4, with
its proximal end affixed to the shaft 4 and its distal end routed
through the payout port 11. The distal end can be coupled to an
anchoring assembly, such as a hook or a carabiner, among a wide
variety of other anchoring devices, as discussed above. Spool
flanges 7 can extend radially from the shaft 4 and be positioned to
maintain the lateral placement of the cord 8 along the shaft 4
during the winding and unwinding of the cord 8. The length of the
cord 8 can vary depending upon the height of the structure with
which the personal escape device 50 is intended to be used.
Furthermore, the sizing and spacing of the spool flanges 7 can vary
based on the size and length of the cord 8 that is wound around the
shaft 4.
[0038] A magnet housing 3 is positioned within the housing 1 and
coupled to the shaft 4, such that rotation of the shaft 4 rotates
the magnet housing 3. In the illustrated embodiment, magnet
housings 3 are each positioned proximate to lateral ends of the
shaft 4. In some embodiments a magnet housing cap 3a is coupled to
the magnet housing 3, and one or more magnets 2 are coupled to the
magnet housing 3. In the illustrated embodiment, the magnets 2 are
coupled around the outer periphery of the magnet housing 3. Thus,
rotation of the shaft 4, which can be caused by the unwinding cord
8, causes the magnets 2 to rotate. To facilitate ease of rotation
of the shaft 4 relative to the housing 1, roller bearings 5 can be
utilized.
[0039] Conductive rings 6 are positioned within the housing 1 to
surround the magnet housing 3 such that rotation of the magnets 2
proximate to the rings 6 generates eddy currents. The eddy currents
generally are induced by the relative movement of the magnets 2 and
rings 6 through electromagnetic induction. The eddy currents create
a drag force that will oppose the motion of the magnets 2
proportional to its velocity. The rings 6 can be ferrous,
non-ferrous, or combinations thereof. For example, in some
non-limiting embodiments the rings 6 are copper, aluminum, or
steel. The wall thickness of the ring 6 can depend on the type of
material, the size of the personal escape device 50, and/or the
intended use, among other factors. In some embodiments, however,
the rings 6 are copper and can have a lateral width within the
range of about 2 inches to about 4 inches, a diameter within the
range of about 2 inches to 4 inches, and a wall thickness within
the range of about 0.2 inches to 1 inch. In some embodiments,
however, the rings 6 are copper and can have a width of about 2.25
inches to about 4 inches, a diameter of about 3.18 inches, and a
wall thickness of about 0.25 inches. Depending on the material
used, various dimensions can be increased or decreased to achieve
the desired performance without departing from the scope of the
present disclosure.
[0040] FIG. 3 depicts an enlarged cross-sectional view of a lateral
end of the personal escape device 50 of FIG. 1. FIG. 4 is an
exploded view of FIG. 3. As shown in FIG. 3, an air gap 12 is
defined between an inner surface of the ring 6 and the magnets 2
such at that the magnets 2 do not contact the ring 6. In some
embodiments, the air gap 12 is less than 0.10 inches. The shaft 4
can be attached to the spool flange 7 which, in combination with an
oppositely mounted spool flange 7 (FIG. 1), creates the cavity for
the cord 8. FIG. 4 also depicts supporting magnets 2a that are
housed in the magnet housing 3 and are each positioned between
adjacent magnets 2. The shaft 4, the spool flange 7, the magnet
housing cap 3a, the magnets 2, the magnet housing 3, and the
supporting magnets 2a an rotate relative to the ring 6, with the
lateral end of the shaft 4 engaged with the bearing 5.
[0041] FIG. 5 depicts a cross-sectional view of a lateral end of
the personal escape device 50 shown in FIG. 1 taken orthogonal to
the central axis. As illustrated, the magnets 2 and the magnet
housing 3 are centrally positioned within the ring 6. The magnets 2
are positioned to provide an air gap 12 between the ring 6 and
magnets 2.
[0042] FIG. 6 depicts an example arrangement of the magnets 2 that
are coupled to the magnet housing 3. In the illustrated embodiment,
six magnets are used and are arranged in alternating poles in a
radial fashion. The axis of polarity in this arrangement is radial
to the axis of rotation of the shaft. Other arrangements of magnets
can be used without departing from the scope of the present
disclosure.
[0043] FIG. 7 depicts a line feed housing 18 that can be associated
with the personal escape device 50. The line feed housing 18 can be
positioned proximate to the payout port 11, such that the cord 8
unwinding from the shaft 4 is routed through the line feed housing
18. The line feed housing 18 can be integral with the housing 1 or
can be a separate component (as illustrated) that is affixed to a
harness strap 16, for example. In some embodiments, the line feed
housing 18 houses a hand brake 13. The hand brake 13 can be
provided using any suitable configuration, such as a lever, a
rotatable wheel (as illustrated), or a push button, among other
configurations.
[0044] FIG. 8 depicts another embodiment of the line feed housing
18. In this embodiment, a protective channel 10 is routed through
the line feed housing 18. Such line feed housings can be used, for
example, in connection with certain types of harnesses in which
particular routing the cord 8 is desired.
[0045] FIG. 9 depicts a cross-sectional view of an example braking
mechanism in accordance with one non-limiting embodiment. The
braking mechanism includes rollers 14 through which the cord 8 is
routed. A cam 19 is optionally rotated by a user of the personal
escape device, such that rotation of the cam 19 applies a
frictional force to the cord 8, thereby providing mechanical
braking. Actuation of the cam 19 during a descent can, for
instance, cause the user to come to a stop. When the cam 19 is
subsequently rotated to remove the frictional force, the user can
resume the descent.
[0046] FIG. 10a depicts an example routing clip 15 for assisting
with the placement of the protective channel 10 relative to a user.
FIG. 10b depicts a side view of the routing clip 15. The routing
clip 15 can be affixed to the harness strap 16 using a strap
anchoring knob 17. The strap anchoring knob 17 can be turned to
apply pressure on the harness strap 16 preventing the routing clip
15 from moving relative to the harness strap 16. The protective
channel 10 is routed through the routing clip 15, thereby
preventing relevant movement of protective channel 10 and assisting
with the guiding of the cord 8.
[0047] An alternative embodiment of a personal escape device 150 is
illustrated in FIGS. 11-21 and is similar to or the same as in many
respects as the personal escape device 50 illustrated in FIGS.
1-10B. For example, as illustrated in FIG. 11, the personal escape
device 150 can include a main housing 101 and a shaft 104 that is
rotatable with respect to the main housing 101 about a rotational
axis A1 and journalled with respect to the main housing 101 by a
pair bearings 105. A magnet housing 103 (i.e., a rotor assembly)
can be positioned within the main housing 101 and can be coupled to
the shaft 104, such that rotation of the shaft 104 rotates the
magnet housing 103. The magnet housing 103 can be a two-piece
arrangement that comprises a hub 103a and a rotor 103b that are
formed of a metal. As illustrated in FIGS. 11 and 12, the hub 103a
and the rotor 103b can cooperate to retain a plurality of magnets
102 that rotate together with the magnet housing 103. The hub 103a
can be formed of a non-ferrous material. In one embodiment, the
magnets 102 can be permanent magnets, such as NE 52 magnets, for
example. It is to be appreciated that the magnets 102 can be formed
via injection molding, bonding, hot press molding, three
dimensional printing, or any of a variety of suitable alternative
methods. Referring now to FIGS. 11, 13 and 14, a stator assembly
106 (i.e., a plurality of conductive rings) can include a stator
106a and a back iron 106b that overlies the stator 106a such that
the back iron 106b is sandwiched between the stator 106a and the
main housing 101. The stator assembly 106 can be positioned within
the main housing 101 and can surround the magnet housing 103.
[0048] Referring again to FIG. 11, the magnet housing 103 and the
stator 106 can be radially spaced from each other to define an air
gap 112 therebetween such that rotation of the magnet housing 103
correspondingly rotates the magnets 102 with respect to the
conductive rings 106. In one embodiment, the air gap 112 can be
less than about 0.1 inches. The stator 106a can be formed of a
non-ferrous metal such as aluminum or copper, for example, or other
material that facilitates generation of eddy currents when the
magnet housing 103 rotates with respect to the stator assembly 106
thereby imparting a braking force that opposes rotation of the
magnet housing 103. The back iron 106b can be formed of a ferrous
material and can have a thickness that corresponds to the magnetic
mass within the stator assembly 106. In one embodiment, the back
iron 106b can be formed of a rolled perforated sheet of ferrous
material. In such an embodiment, a cooling fluid (e.g., water) can
be imparted to the rolled perforated sheet and can flow through the
perforations to facilitate cooling of the stator assembly 106. In
other embodiments, cooling fluid (e.g., water) can reside in the
air gap 112 to facilitate cooling of the stator assembly 106.
[0049] However, as illustrated in FIGS. 15 and 16, the arrangement
of the magnets 102 and the interaction between the magnets 102 and
the magnet housing 103 can be different from the personal escape
device 50 illustrated in FIGS. 1-10B. For example, as illustrated
in FIG. 15, the magnets 102 are arranged with respect to the shaft
104 such that their axis of polarization is tangential to the
rotational axis A1. The axis of polarization can be understood to
mean the axis that intersects the north and south poles of the
magnet. A portion of each of the hub 103a and the rotor 103b can be
interposed between each magnet 102 and an adjacent magnet 102
thereby providing a salient pole arrangement that focuses the
magnetic flux into the stator 106a. The portion of the magnet
housing 103 that is interposed between each magnet 102 and the
adjacent magnet 102 can be configured to transmit the entirety of
the flux density from each magnet 102 to the stator assembly 106.
In one embodiment, the portion of the magnet housing 103 that is
interposed between each magnet 102 can have sufficient thickness,
mass and permeability to transmit the entirety of the flux density
from the magnet 102 to the stator assembly 106. Referring now to
FIG. 16, the magnets 102 can be arranged such that the north-south
pole directions of each magnet 102 align between adjacent magnets
102. In such an arrangement, the back iron 106b can act as a return
path for the magnetic flux such that it circulates back into the
stator assembly 106 allowing for the eddy current to increase in
strength thus providing a much larger torque curve than
conventional arrangements.
[0050] It is to be appreciated that arranging the magnets 102
axially as described can impart a rotating radial flux pattern
which can be more effective at imparting a braking force than
conventional arrangements that impart an axial reciprocating flux
pattern. It is also to be appreciated that the magnets 102 and the
magnet housing 103 can cooperate to form any of a variety of rotor
configurations, such as SPM and IPM rotor configurations which can
include a radial pole arrangement, a bread loaf arrangement, a
radial and salient arrangement, an outside poles arrangement, a
spoke IPM arrangement, a V-pole IPM arrangement or the like.
[0051] It is to be appreciated the thickness of the air gap 112,
the thickness of the stator 106a, the thickness of the back iron
106b, the quantity and arrangement of magnet(s) 102, and/or the
gausing strength and polarity of the magnets 102 can be selected to
achieve a more compact design that yields higher weight capacities
than conventional arrangements. For example, the thickness of the
hub 103a, the rotor 103b, the stator 106a, and the back iron 106b
can be selected to achieve a braking force to suit a particular
application (e.g., fire and rescue) for the personal escape device
150. It is also to be appreciated that the arrangement of the
magnets 102, magnet housing 103, and the stator assembly 106
disclosed herein can result in a lighter, more compact, more
portable design that is more readily available for personal use and
that provides higher eddy currents (e.g., higher braking force)
than conventional arrangements.
[0052] Referring again to FIG. 11, a pulley 152 can be attached to
the shaft 104 such that rotation of the pulley 152 correspondingly
rotates the magnet housing 103 (via the shaft 104). The pulley 152
can comprise a pair of disc members 152 (FIGS. 18 and 19). As
illustrated in FIG. 17, one of the disc members 152 is illustrated
and can be understood to be representative of the other disc member
152 in the pair. Each disc member 152 can include an internal
surface 156 having lateral elongated projections 158 extending
upwardly therefrom. The lateral elongated projections 158 can
extend substantially tangentially from a central hub 160. The
internal surface 156 of the disc members 152 can be substantially
convex shaped such that the profile of the lateral elongated
projections 158 are crowned as they extend away from the central
hub 160. As illustrated in FIGS. 18 and 19, the disc members 152
can be sandwiched together and arranged with the internal surfaces
156 facing each other such that the disc members 152 cooperate to
define a V-shaped groove 162.
[0053] Referring now to FIGS. 20 and 21, the pulley 152 can include
a pulley housing 164 that houses the disc members 152, one of which
has been removed for clarity of illustration. The pulley housing
164 can define an input port 166 and an output port 168 for a cord
108. The cord 108 can be routed through the input port 166, around
the central hub 160, and out of the output port 168 such that the
cord 108 is only partially wound upon the disc members 152. The
cord 108 accordingly does not collect on the disc members 152
(e.g., the cord 108 does not overlap at the disc members 156), but
instead is paid off from a location outside of the personal escape
device 150 as will be described in further detail below. In one
embodiment, the input port 166 and the output port 168 can be
located on the same side of the pulley housing 164 such that the
path of the cord 108 is substantially U-shaped. A self-tailoring
mechanism 170 can be interposed between the input port 166 and the
output port 168 and facilitate effective routing of the cord 108
through the pulley 152 (e.g., through the input port 166, around
the central hub 160, and out of the output port 168).
[0054] When the cord 108 has slack and is initially withdrawn from
the output port 168 (e.g., when a user begins descending from a
building), the input port 166 and the self-tailoring mechanism 170
can cooperate to apply initial tension the cord 108 which draws the
cord towards the central hub 160. As the cord 108 is drawn closer
to the central hub 160 and is pulled deeper into the V-shaped
groove 162, the lateral elongated projections 158 become
increasingly embedded into the cord 108 thereby gripping the cord
108 to facilitate rotation of the disc members 152. As the disc
members 152 rotate, eddy currents are produced between the magnet
housing 103 and the stator assembly 106 which inhibits rotation of
the disc members 152 thereby applying a braking force to the disc
members 152. This braking force slows the unwinding of the cord 108
to accordingly slow a user's vertical descent.
[0055] It is to be appreciated that the cord 108 can be fed into
the input port 166 from any of a variety of suitable payout
devices. In one example, the cord 108 can be paid out from a bag
that is attached to the user proximate the personal escape device
150 and that travels together with the user during descent. It is
to be appreciated that any of a variety of other pulley
arrangements are contemplated such as a capstan, a reel, or a
sheave (e.g., a pulley block), for example.
[0056] In an alternative embodiment, the magnets 102, the magnet
housing 103 and the stator assembly 106 illustrated in FIGS. 11-16
can be provided on opposite sides of a common shaft (e.g., 4)
similar to the embodiment(s) disclosed in FIGS. 1-10B. In such an
embodiment, the magnets 102, the magnet housing 103 and the stator
assembly 106 on each side of the shaft (e.g., 4) can cooperate to
impart braking force to the shaft (e.g., 4) when a cord (e.g., 8)
is unwound therefrom.
EXAMPLES
[0057] Testing was conducted on four different prototype personal
escape devices (B1, B2, B3, B4), the results of which are depicted
in the plot of FIG. 22 that illustrates the relationship between
the total mass imparted on the cord of each personal escape device
and the resulting terminal descent velocity of the mass attached to
the cord. Each prototype configuration had eight neodymium magnets
(Grade N52) oriented to create 8 salient poles between magnet
pairs. A 200 pound payload and frictionless line payout were
assumed.
[0058] The descent velocity was calculated using the following
equation:
v ( t ) = mg b ( 1 - e - bt m ) + v i e - bt ##EQU00001##
[0059] which is the closed form solution to the differential
equation representing a falling payload retarded by a rotary
damping element. The damping coefficient (e.g. relationship between
input speed and output torque) was measured directly by a
dynamometer.
[0060] Example B1 was comprised of an all steel rotor, steel shaft,
aluminum stator, and back iron of various thicknesses. Example B1.1
had a back iron thickness of about 0.1 inch, and Example B1.15 had
a back iron thickness of about 0.15 inch. Increasing the back iron
thickness from about 0.1 inch to about 0.15 inch further improves
the permeability of magnetic flux, resulting in a slight
improvement in the descent velocity.
[0061] Example B2 was comprised of aluminum and steel rotor, steel
shaft, aluminum stator, and back iron of various thicknesses.
Example B2.0 had no back iron, and Example B2.1 had about 0.02 inch
of back iron, B2.2 had about 0.04 inch of back iron, and B2.3 had
about 0.06 inch of back iron. In this configuration, the rotor hub
material is aluminum. Aluminum has a very low magnetic permeability
which forces more magnetic flux through the stator, accounting for
the significant performance improvement over B1, which had an all
steel rotor. Improvements in performance are achieved going from
about 0.0 inch of back iron to about 0.04 inch of back iron. Only
marginal performance gains are achieved at back iron thickness of
about 0.06 inch and greater because the back iron is no longer
saturated at thickness near about 0.06 inch.
[0062] Example B3 is comprised of aluminum and steel rotor,
aluminum shaft, aluminum stator, and back iron of various
thicknesses. B3.0 has no back iron. B3.1 has about 0.02 inch of
back iron, B3.2 has about 0.04 inch of back iron, and B3.3 has
about 0.06 inch of back iron. In this configuration, both the rotor
hub and shaft material is aluminum. The addition of the Aluminum
shaft directs slightly more magnetic flux through the stator,
resulting in a slight improvement in performance relatives to B2,
which had a steel shaft. Similar to B2, dramatic improvements in
performance are achieved going from about 0.0 inch of back iron to
about 0.04 inch of back iron. Again, only marginal performance
gains are achieved at back iron thickness of about 0.06 inch and
greater because the back iron is no longer saturated.
[0063] Example B4 is comprised of aluminum and steel rotor,
aluminum shaft, copper stator, and back iron of various
thicknesses. B3.0 has no back iron, and B3.1 has about 0.02 inch of
back iron, B3.2 has about 0.04 inch of back iron, B3.3 has about
0.06 inch of back iron. In this configuration, both the rotor hub
and shaft material is aluminum. The addition of the Aluminum shaft
directs slightly more magnetic flux through the stator, resulting
in a slight improvement in performance relatives to B2, which had a
steel shaft. Similar to B2, dramatic improvements in performance
are achieved going from about 0.0 inch of back iron to about 0.04
inch of back iron. Again, only marginal performance gains are
achieved at back iron thickness of about 0.06 inch and greater
because the back iron is no longer saturated.
[0064] The examples discussed herein are examples only and are
provided to assist in the explanation of the apparatuses, devices,
systems and methods described herein. None of the features or
components shown in the drawings or discussed below should be taken
as mandatory for any specific implementation of any of these the
apparatuses, devices, systems or methods unless specifically
designated as mandatory. For ease of reading and clarity, certain
components, modules, or methods may be described solely in
connection with a specific figure. Any failure to specifically
describe a combination or sub-combination of components should not
be understood as an indication that any combination or
sub-combination is not possible. Also, for any methods described,
regardless of whether the method is described in conjunction with a
flow diagram, it should be understood that unless otherwise
specified or required by context, any explicit or implicit ordering
of steps performed in the execution of a method does not imply that
those steps must be performed in the order presented but instead
may be performed in a different order or in parallel.
[0065] In various embodiments disclosed herein, a single component
can be replaced by multiple components and multiple components can
be replaced by a single component to perform a given function or
functions. Except where such substitution would not be operative,
such substitution is within the intended scope of the
embodiments.
[0066] The foregoing description of embodiments and examples has
been presented for purposes of illustration and description. It is
not intended to be exhaustive or limiting to the forms described.
Numerous modifications are possible in light of the above
teachings. Some of those modifications have been discussed, and
others will be understood by those skilled in the art. The
embodiments were chosen and described in order to best illustrate
principles of various embodiments as are suited to particular uses
contemplated. The scope is, of course, not limited to the examples
set forth herein, but can be employed in any number of applications
and equivalent devices by those of ordinary skill in the art.
* * * * *