U.S. patent application number 11/859064 was filed with the patent office on 2009-03-26 for anti-twist device.
Invention is credited to Roger Dick, Joe Esteireiro, Jean-Marc Girardin.
Application Number | 20090078811 11/859064 |
Document ID | / |
Family ID | 39930015 |
Filed Date | 2009-03-26 |
United States Patent
Application |
20090078811 |
Kind Code |
A1 |
Dick; Roger ; et
al. |
March 26, 2009 |
ANTI-TWIST DEVICE
Abstract
The embodiments described and claimed herein relate to opening
in a housing for a retractor. The opening includes structures which
reduce the risk of twisting webbing passing through the opening
and, thereby, interfering with the proper functionality of the
retractor. The openings can include one or more guide surfaces
which incorporate some combination of features which smooth out the
webbing as it enters the retractor and/or urge the webbing into
alignment with the retractor opening. In addition, or in the
alternative, the height of the opening can be modified to closely
conform to the maximum thickness of the webbing. The guide surfaces
can be integrally formed with the retractor housing or can be
provided by an insert piece which attaches to the housing. In one
embodiment, the guide surface is disposed along an upper wall of
the opening and is curvilinear and outwardly diverging. More
specifically, the guide surface has slopes that vary along its
length whereby the guide surface is approximately vertical near a
leading edge of the guide surface and is approximately horizontal
near a trailing edge of the guide surface.
Inventors: |
Dick; Roger; (Tamarac,
FL) ; Esteireiro; Joe; (Weston, FL) ;
Girardin; Jean-Marc; (Golden Beach, FL) |
Correspondence
Address: |
David I. ROCHE;BAKER & McKENZIE
130 E. Randolph Drive
Chicago
IL
60601
US
|
Family ID: |
39930015 |
Appl. No.: |
11/859064 |
Filed: |
September 21, 2007 |
Current U.S.
Class: |
242/397 |
Current CPC
Class: |
B60R 22/18 20130101;
A61G 5/10 20130101; A61G 1/044 20130101; B60R 2022/1818
20130101 |
Class at
Publication: |
242/397 |
International
Class: |
B65H 81/00 20060101
B65H081/00 |
Claims
1. A device for reducing the chances that a twisted portion of a
restraint strap will interfere with the operation of a retractor
comprising: a housing, a retractor spool, and a restraint strap,
the restraint strap being wound on the retractor spool and having a
thickness; the housing defining an interior space in which a
retractor spool is disposed and having an opening which is adapted
for passing the strap therethrough; and, the opening having an
effective height which is between approximately two and eight times
the thickness of the restraint strap to allow a double stitched
portion of the restraint strap to pass therethrough.
2. The device of claim 1, wherein the effective height is between
approximately two and six times the thickness of the restraint
strap.
3. The device of claim 1, wherein the housing is a retractor
cover.
4. The device of claim 1, wherein the housing is a barrier
housing.
5. The device of claim 1, wherein the opening is provided with at
least one guide surface, the guide surface having at least one
slope between a leading edge and a trailing edge, wherein the at
least one slope causes the leading edge to diverge from an opposing
sidewall.
6. The device of claim 5, wherein the at least one slope comprises
at least a first slope near the leading edge and at least a second
slope near the trailing edge, wherein the guide surface is aligned
approximately perpendicular to an axis of the opening near the
leading edge and is aligned approximately parallel to the axis of
the opening near the trailing edge.
7. The device of claim 6, wherein the guide surface is curvilinear
and includes a variable slope between the leading and trailing
edges.
8. The device of claim 1, wherein the opening includes a plurality
of contoured guide surfaces, at least one of which is adapted to
guide the movement of the lateral edges of the strap.
9. The device of claim 1, wherein a guide surface for the opening
is formed on a member which is attachable to the housing, the guide
surface constricting a size of the opening to provide the opening
with the effective height.
10. The device of claim 9, wherein the member includes at least one
locking groove whereby the member can be engaged with the opening
by snapping into place.
11. The device of claim 1, wherein the opening is generally
quadrangular and includes four walls, onto one of which at least
one guide surface is formed.
12. A device for reducing the chances that a twisted portion of a
restraint strap will interfere with the operation of a retractor
comprising: a housing, a retractor spool, and a restraint strap,
the restraint strap being wound on the retractor spool and having a
thickness; the housing defining an interior space in which a
retractor spool is disposed and having an opening which is adapted
for passing the strap therethrough; the opening having at least one
sidewall, with at least a portion of the sidewall having a guide
surface, the guide surface being configured to guide the movement
of the strap and thereby resist the passing of a twist in the strap
through the opening and into the housing; and, the guide surface
having a leading edge and a trailing edge, the guide surface
extending a distance into the opening whereby the trailing edge is
disposed within the interior space of the housing.
13. The device of claim 12, wherein the housing is a retractor
cover.
14. The device of claim 12, wherein the housing is a barrier
housing.
15. The device of claim 12, wherein the trailing edge of the guide
surface is disposed in close proximity to the retractor spool.
16. The device of claim 12, wherein the guide surface has at least
one slope between the leading edge and the trailing edge, wherein
the at least one slope causes the leading edge to diverge from an
opposing sidewall.
17. The device of claim 16, wherein the at least one slope
comprises at least a first slope near the leading edge and at least
a second slope near the trailing edge, wherein the guide surface is
aligned approximately perpendicular to an axis of the opening near
the leading edge and is aligned approximately parallel to the axis
of the opening near the trailing edge.
18. The device of claim 12, wherein the guide surface is
curvilinear and includes a variable slope between the leading and
trailing edges.
19. The device of claim 12, wherein the opening includes a
plurality of contoured guide surfaces, at least one of which is
adapted to guide the movement of the lateral edges of the
strap.
20. The device of claim 12, wherein the guide surface for the
opening is formed on a member which is attachable to the
housing.
21. The device of claim 20, wherein the member includes at least
one locking groove whereby the member can be engaged with the
opening by snapping into place.
22. The device of claim 12, wherein the opening is generally
quadrangular and includes four walls, onto at least one of which
the guide surface is formed.
23. A device for reducing the chances that a twisted portion of a
restraint strap will interfere with the operation of a retractor
comprising: a housing, a retractor spool, and a restraint strap,
the restraint strap being wound on the retractor spool and having a
thickness; the housing defining an interior space in which a
retractor spool is disposed and having an opening which is adapted
for passing the strap therethrough; the opening having an effective
height which is between approximately two and eight times the
thickness of the restraint strap to allow a double stitched portion
of the restraint strap to pass therethrough; the opening having at
least one sidewall, with at least a portion of the sidewall having
a guide surface, the guide surface being configured to guide the
movement of the strap and thereby resist the passing of a twist in
the strap through the opening and into the housing; and, the guide
surface having a leading edge and a trailing edge, the guide
surface extending a distance into the opening whereby the trailing
edge is disposed within the interior space of the housing.
24. The device of claim 23, wherein the effective height is between
approximately two and six times the thickness of the restraint
strap.
25. The device of claim 23, wherein the housing is a retractor
cover.
26. The device of claim 23, wherein the housing is a barrier
housing.
27. The device of claim 23, wherein the trailing edge of the guide
surface is disposed in close proximity to the retractor spool.
28. The device of claim 23, wherein the guide surface has at least
one slope between a leading edge and a trailing edge, wherein the
at least one slope causes the leading edge to diverge from an
opposing sidewall.
29. The device of claim 28, wherein the at least one slope
comprises at least a first slope near the leading edge and at least
a second slope near the trailing edge, wherein the guide surface is
aligned approximately perpendicular to an axis of the opening near
the leading edge and is aligned approximately parallel to the axis
of the opening near the trailing edge.
30. The device of claim 29, wherein the guide surface is
curvilinear and includes a variable slope between the leading and
trailing edges.
31. The device of claim 30, wherein the opening includes a
plurality of contoured guide surfaces, at least one of which is
adapted to guide the movement of the lateral edges of the
strap.
32. The device of claim 30, wherein a guide surface for the opening
is formed on a member which is attachable to the housing, the guide
surface constricting a size of the opening to provide the opening
with the effective height.
33. The device of claim 32, wherein the member includes at least
one locking groove whereby the member can be engaged with the
opening by snapping into place.
Description
FIELD OF THE INVENTIONS
[0001] The embodiments described and claimed herein relate
generally to wheelchair securement devices for vehicles. More
specifically, one embodiment described herein relates to a
retractor cover, which includes features to prevent twisted webbing
or restraint strap from passing into the retractor housing. Another
embodiment relates to a retrofit insert for a retractor cover,
which includes similar anti-twist features. Yet another embodiment
relates to an anti-twist guide slot, or retrofit insert for a slot,
which could be used in a location remote from the retractor.
BACKGROUND OF THE INVENTIONS
[0002] Retractors are utilized in a number of different
applications, such as safety harnesses, automobile seatbelt
systems, and wheelchair securement systems for vehicles. The
particular embodiments disclosed herein are primarily adapted for
use in wheelchair securement systems for restraining both the
wheelchair and the wheelchair passenger, although it is envisioned
that the features shown and described herein could be utilized in
an equally effective manner in other applications.
[0003] It is well known that retractors can be installed in a
number of different configurations. In a most simple application,
four retractors can be mounted to a vehicle's floor or near
thereby, one for securing each corner of a wheelchair. For examples
of prior art retractors, see Q'Straint's QRT retractors at
www.qstarint.com and Sure-Lok's Retraktor Series System at
www.sure-lok.com. Since floor-mounted retractors can present
serious tripping hazards for vehicle passengers, manufacturers have
developed various apparatus for reducing or minimizing the tripping
hazard. For example, as described in U.S. patent application Ser.
No. 11/776,223, which is incorporated herein by reference,
Q'Straint has developed a retractable wheelchair anchor onto which
two retractors can be mounted. Q'Straint's wheelchair anchor
includes a foot-operated telescoping arm, which retracts into a
non-use position to present a lesser tripping hazard than
floor-mounted retractors. See also American Seating's Advanced
Restraint Module ("A.R.M.") at www.americanseating.com. Q'Straint
has also developed a forward facing barrier system as disclosed in
U.S. patent application Ser. No. 11/847,435, which is incorporated
herein by reference. Q'Straint's forward facing barrier includes a
housing for concealing internally mounted retractors, whereby the
webbing from each retractor passes through a corresponding slot in
the barrier housing.
[0004] In wheelchair securement applications, retractors often
include up to several feet of webbing. At its proximal end, the
webbing is attached to a spring loaded spool which is disposed
within a cover or housing. At its free end, the webbing is
typically attached to an anchor (such as an S-hook or J-hook),
which is adapted to engage with a structural member of a
wheelchair, thereby securing the wheelchair. Alternatively, the
webbing can be adapted for use as a lap or shoulder belt for the
wheelchair passenger and, for such applications, can include some
sort of a connector, such as a male, female, or pin connector.
[0005] When used in exposed applications--for example, if the
retractors are floor-mounted or mounted onto a retractable
wheelchair anchor--the retractor will usually include a metal or
plastic cover for housing and protecting the working components of
the retractor. When used in non-exposed applications--such as when
mounted internal to the barrier housing--use of a zinc cover is
prohibitively expensive. For this reason, manufacturers often will
not use a separate cover (or housing) for the retractor and will
instead rely upon the barrier housing to protect the retractor.
Alternatively, manufacturers may use an inexpensive cover, such as
a plastic one.
[0006] While all current wheelchair retractors are vulnerable to
twists in the webbing, self-locking retractors are particularly so
since they have openings which are relatively large, having an
effective height which is generally more than ten (10) times the
thickness of the webbing itself. The openings are large since
self-locking retractors utilize a double stitched portion of
webbing, which must be passed through the opening to enable the
self-locking feature. The double stitched portion of webbing is
simply the free end of the webbing that is looped through the
anchor, folded back over itself, and stitched together. When the
webbing is fully retracted, a length of double stitched webbing is
wound on the retractor spool such that it triggers a locking bar.
In this configuration, the retractor is "unlocked," such that the
webbing can be freely pulled out of the retractor. When the double
stitched portion of webbing is pulled out of the retractor, the
locking bar is released, but does not fully engage (i.e., to
prevent further extension of the webbing) until the attendant stops
pulling on the webbing and allows the self-tensioning feature of
the retractor to retract a small amount of webbing.
[0007] In typical use of any of the above described wheelchair
securement systems, an attendant (or vehicle operator) grasps and
pulls the anchor (or lap and shoulder belt connectors), thereby
drawing webbing out from the retractor spool, and attaches the
anchor to a structural member of the wheelchair (or attaches the
lap and shoulder belts together). Often times, the attendant will
introduce twists into the webbing which may not be "undone" when
the anchor is released from the wheelchair (or the lap belt is
released). The twist may pass through the housing and become wound
onto the retractor spool (note that, for the above described
wheelchair securement systems, the term housing refers to either or
both the retractor cover and barrier housing). Once the twist is
wound onto the retractor spool, the twist can interfere with proper
functioning of the retractor such that the efforts required to pull
the webbing from the retractor are increased. Moreover, the twist
may cause the webbing to overlap the gears, which in turn causes
accelerated wear of the webbing and could possibly jam the
retractor. Sometimes, it may be impossible to extend the webbing
without disassembling the retractor or the barrier. In such cases,
the retractor will not work and, hence, the securement system will
be unusable.
[0008] Wheelchair securement system manufacturers, being aware of
and until now being unable to solve these problems, instruct their
customers to regularly inspect for twists in the webbing. Ideally,
a vehicle operator will inspect the webbing for twists every time
before securing a wheelchair. In the case of mass transit vehicles,
this additional step increases the dwell time at stops and
increases the risk of the operator suffering from a back
injury.
SUMMARY OF THE INVENTIONS
[0009] The embodiments described and claimed herein at least
partially reduce the risk of twisting. As discussed briefly above,
it is believed that the configuration (i.e. size and or shape) of
the prior art openings (or guide slots) allow the twists to pass
through unimpeded. Therefore, the openings shown and described
herein incorporate some combination of features which smooth out
the webbing as it passes through the opening and/or urge the
webbing into alignment with the opening. In this manner, the
embodiments described, shown, and claimed herein reduce the chances
that the webbing will fold over into a double thickness and become
wound onto the retractor spool.
[0010] For example, one embodiment described herein is a housing
for a retractor. The housing, in turn, defines an interior space in
which the working components of the retractor are disposed and has
an opening which is adapted for passing webbing therethrough. The
opening in the housing has at least one guide surface which is
integrally formed therein. The guide surface is configured to guide
the movement of the webbing and thereby resist the passing of
twists in the webbing through the opening. More specifically, the
guide surface has a leading edge being disposed generally near an
outside the housing, a trailing edge, and at least one slope
therebetween, wherein the at least one slope causes the leading
edge to diverge from the opening. In another embodiment, the
housing for the retractor is a retractor cover. In yet another
embodiment, the retractor is internally mounted in a barrier,
whereby the housing for the retractor is a barrier housing.
[0011] Another embodiment described herein is a retrofit insert
piece or webbing guide which is adapted to attach to a housing for
a retractor and which provides at least one guide surface for the
opening in the housing. Like the guide surface of the first
embodiment, the guide surface of the second embodiment serves to
resist a twist in the webbing from passing through the opening.
More specifically, at least a portion of the guide surface is
aligned in non-parallel relation to the axis of the opening,
whereby the portion the guide surface is outwardly diverging. In
another embodiment, the housing for the retractor is a retractor
cover. In yet another embodiment, the retractor is internally
mounted in a barrier, whereby the housing for the retractor is a
barrier housing.
[0012] Other embodiments, which include some combination of the
features discussed above and below and other features which are
known or unknown in the art, are contemplated as falling within the
claims even if such embodiments are not specifically identified or
discussed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] These and other features, aspects, objects, and advantages
of the embodiments described and claimed herein will become better
understood upon consideration of the following detailed
description, appended claims, and accompanying drawings where:
[0014] FIG. 1 is a perspective view of a first embodiment of a
retractor housing, which includes integrally formed guide surfaces
at the opening of the housing;
[0015] FIG. 2 is a first perspective, exploded view of the
same;
[0016] FIG. 3 is a second perspective, exploded view of the
same;
[0017] FIG. 4 is a cross sectional view of the same;
[0018] FIG. 5 is a top view of a lower member of the retractor
housing;
[0019] FIG. 6 is a bottom view of an upper member of the retractor
housing;
[0020] FIG. 7 is a perspective view of a second embodiment of a
retractor, which includes a retrofit webbing guide;
[0021] FIG. 8 is a perspective view of the retrofit webbing
guide;
[0022] FIG. 9 is a front view of the same;
[0023] FIG. 10 is a bottom view of the same;
[0024] FIG. 11 is a cross sectional view of the same;
[0025] FIG. 12 is a perspective view of the second embodiment of
the retractor, which the retrofit webbing guide partially inserted
into the opening in the retractor housing;
[0026] FIG. 13 is a cross-sectional view of the first embodiment of
the retractor housing, showing the relative location of the upper
guide surface with the internal mechanisms of the retractor;
[0027] FIG. 14 is a cross-sectional view of the second embodiment
of the retractor housing, showing the relative location of the
retrofit insert with the internal mechanisms of the retractor;
[0028] FIG. 15 is a forward facing barrier which includes
anti-twist guide slots for wheelchair securement and lap and
shoulder belt retractors;
[0029] FIG. 16 is a close-up view of the same showing the
anti-twist guide slots for the wheelchair securement and lap belt
retractors;
[0030] FIG. 17 is a close-up view of the same showing the
anti-twist guide slots for the shoulder belt retractor; and,
[0031] FIG. 18 is a perspective view of a second embodiment of a
retrofit webbing guide.
[0032] It should be understood that the drawings are not
necessarily to scale and that the embodiments are sometimes
illustrated by graphic symbols, phantom lines, diagrammatic
representations and fragmentary views. In certain instances,
details which are not necessary for an understanding of the
embodiments described and claimed herein or which render other
details difficult to perceive may have been omitted. It should be
understood, of course, that the inventions described herein are not
necessarily limited to the particular embodiments illustrated.
Indeed, it is expected that persons of ordinary skill in the art
may devise a number of alternative configurations that are similar
and equivalent to the embodiments shown and described herein
without departing from the spirit and scope of the claims.
[0033] Like reference numerals will be used to refer to like or
similar parts from Figure to Figure in the following detailed
description of the drawings.
DETAILED DESCRIPTION OF THE DRAWINGS
[0034] Various embodiments of an anti-twist slot or opening for
passing webbing therethrough are described and shown herein which
incorporate some combination of features which substantially reduce
the chance that twisted webbing will become wound onto a retractor
spool and therefore interfere with the functionality of a
retractor. Some of the features of the openings which make this
possible relate to the height of the opening as compared to the
thickness of the webbing, the length of the innermost guide surface
on the upper wall (or various other walls depending upon
orientation), the proximity of the innermost guide surface on the
upper wall (or various other walls depending upon orientation) to
the retractor spool, the aspect ratios of the opening, and/or the
contours of the opening side walls. Although the embodiments
depicted herein include openings having specific aspect ratios and
specific contours, it is in no way intended that the inventions be
limited to those specific values or those specific combinations of
aspect ratios and contours. The specific dimensions recited herein
are for example purposes only and apply only to the specific
embodiments shown in the figures. The dimensions are not intended
to be limiting upon the claims except to the extent that specific
dimensions are explicitly recited therein. Indeed, the dimensions
could vary widely (even outside the specific ranges provided
herein) depending on various factors, including the type of
application, the length and thickness of the webbing, etc.
[0035] Referring first to FIGS. 1-6 and 13, a first embodiment of a
housing 10 for a retractor is depicted. The retractor housing 10 of
the first embodiment is a retractor cover and comprises an upper
member 20 and a lower member 30, which are adapted to engage and
thereby form an enclosure. Although not all components are shown,
the housing is intended to enclose and protect the various working
components of the retractor, including a spring loaded spool
mechanism 22, which in turn carries webbing 14. Although the
housing 10 is comprised of two members 20, 30, it is contemplated
that the housing 10 could be defined by more or less members.
[0036] The upper member 20 and lower member 30 merge to define an
opening 40, through which the webbing is intended to pass. The
opening 40 can be any shape (for example, such as oval or
hexagonal), but as shown is generally quadrangular wherein the
opening 40 is defined by four side walls 50, 60, 70, 80. The four
sidewalls 50, 60, 70, 80 are guide surfaces and, as shown, are
generally curvilinear and inwardly converge towards each other (or,
in other words, outwardly diverge). Although all four sidewalls 50,
60, 70, 80 of the shown embodiment are configured as guide
surfaces, it is contemplated that less than all of the side walls
could be configured as such. In fact, configuring the opening with
a single guide surface may be sufficient.
[0037] For purposes of this description, it is assumed that the
retractor housing 10 is horizontally oriented. Therefore, the first
sidewall 50 is referred to herein as an upper sidewall 50, the
second sidewall 60 is referred to herein as a lower sidewall 60,
the third sidewall 70 is referred to herein as a left sidewall, and
the fourth sidewall 80 is referred to herein as a right sidewall.
However, since it is contemplated that the retractor housing 10
could be oriented vertically or in an inclined configuration, the
use of the terms upper and lower are used for purposes of
description and not for purposes of defining the relative location
of these walls when the retractor housing is installed.
[0038] The upper sidewall 50, as shown, includes several guide
surfaces or portions and is both curvilinear and inwardly
converging, although it is contemplated that the upper sidewall 50
could be entirely linear, or include linear portions. As best shown
in FIG. 4, the upper sidewall 50 has slopes that vary along its
length (i.e., in the direction of travel of the webbing) and, as
shown, has an inner portion 52 and an outer portion 54. Starting
from an inner extent of the inner portion 52 and moving outwardly,
the inner portion 52 is approximately linear and parallel with the
axis of the opening and/or the general plane along which the
webbing travels, although it is contemplated that the inner portion
52 could be curvilinear and oriented an angle to the axis of the
opening. The intersection 56 between the inner portion 52 and the
outer portion 54 is characterized by a substantial increase in
slope along its length. In that respect, the upper sidewall 50
begins to diverge from the lower side wall 60 near or at the
intersection 56. The intersection 56 has an approximate radius of
0.20'', although radii in the range of approximately 0.1'' to 0.3''
would also be sufficient. The upper sidewall 50 continues to
diverge from the lower sidewall along the length of the outer
portion 54, although to a much greater extent than at the
intersection 56. The outer portion 54 is marked by a gradual
increase in slope and, at an outer extent, approaches approximately
vertical. The outer portion 54 has a radius of approximately 0.30''
near its midpoint, although a radius of approximately 0.20'' to
0.40'' would also be sufficient.
[0039] For a horizontally oriented retractor, it has been found
that the upper sidewall 50 contributes more significantly to the
anti-twist capability of the retractor housing, than do the other
sidewalls 60, 70, 80. It has also been found that some features of
the upper wall 50 contribute more significantly to the anti-twist
capability of the retractor. For example, it is believed that
better results can be obtained by maximizing the length of the
inner portion of the upper sidewall 50 and positioning the inner
extent of the inner portion 52 as near as possible to the spool
mechanism or the webbing which is wound thereon. In fact, for a
horizontally oriented retractor, it is believed that satisfactory
results could be obtained by merely configuring the upper wall as a
planar surface which extends a distance from an outside surface of
the retractor housing into the opening.
[0040] Like the upper sidewall 50, the lower sidewall 60, as shown,
is both curvilinear and inwardly converging. As best shown in FIG.
4, the lower sidewall 60 has slopes that vary along its length and,
as shown, has an inner portion 62 and an outer portion 64. Starting
from the inside of the housing 10 and moving outwardly, the inner
portion 62 is substantially parallel with the axis of the opening
and/or the general plane along which the webbing travels. The
intersection 66 between the inner portion 62 and the outer portion
64 is characterized by a substantial decrease in slope along its
length. In that respect, the lower sidewall 60 begins to diverge
from the upper side wall 56 near or at the intersection 66. The
intersection has an approximate radius of 0.34'', although a radius
in the range of approximately 0.24'' to 0.44'' would also be
sufficient. The lower sidewall 60 continues to diverge from the
upper sidewall 50 along the length of the outer portion 64,
although to a slightly greater extent than at the intersection 66.
The outer portion 64 is marked by a gradual decrease in slope and,
at an outer extent, passes through vertical.
[0041] The left and right sidewalls 70, 80 are essentially mirror
images of each other. For that reason, only the left sidewall 70 is
described in detail herein. As best shown in FIG. 5, the left
sidewall 70 (like both the upper and lower sidewalls 50, 60) is
both curvilinear and inwardly converging. Moreover, the left
sidewall 70 includes an inner portion 72 and an outer portion 74,
which merge at an intersection 76. The length of the inner portion
72 is aligned substantially parallel with the direction of travel
of the webbing and/or the axis of the opening, while the outer
portion diverges away from the axis of the opening at an angle of
approximately 32 degrees. It is contemplated, however, that the
outer portion could be oriented at other angles, such as between
approximately 30 degrees to 45 degrees. The intersection 56, as
shown, has a radius of approximately 0.20'' although a radius in
the range of 0.10'' to 0.30'' would also be sufficient.
[0042] The outer portions 54, 64, 74, 84 of the sidewalls 50, 60,
70, 80 can be characterized as smoothing surfaces. Since these
portions 54, 64, 74, 84 of the sidewalls are marked by gradual
changes in slope and/or generally diverge from the axis of the
opening, it is believed that these surfaces exert only low to
moderate untwisting forces on the webbing. The inner portions 52,
62, 72, 82 and/or the intersections 56, 66, 76, 86 of the sidewalls
50, 60, 70, 80 can be characterized as urging surfaces, as they are
marked by a greater change in slope and/or are substantially
parallel with the axis of the opening. It is believed that the
urging surfaces are more capable of exerting greater untwisting
forces on the webbing. When both are present, the smoothing and
urging surfaces cooperatively work to prevent twisted webbing from
passing through the opening 40.
[0043] In additional or in the alternative to the various contours
of the sidewalls 50, 60, 70, 80, it is believed that the aspect
ratios of the opening 40 contribute to the untwisting capabilities
of the retractor housing 10. The opening 40 can be characterized as
having major dimensions of W.sub.1.times.H.sub.1 and minor (or
effective) dimensions of W.sub.2.times.H.sub.2. At some point along
the depth D of the opening 40, there is an intermediate plane where
the opening 40 has intermediate dimensions which are approximately
equal to or slightly greater than the minor dimensions. The
intermediate plane occurs at a depth D1 from the outer extent of
the opening 40. The location of the intermediate plane
approximately corresponds with the location of the intersections
56, 66, 76, 86, at the point at which the opening 40 begins to
substantially diverge outwardly. In the shown embodiment, W.sub.1
is approximately equal to 2.3'', W.sub.2 is approximately equal to
1.96'', H.sub.1 is approximately equal to 1'', H.sub.2 is
approximately equal to 0.24'', D is approximately equal to 0.40'',
and D1 is approximately equal to 0.20''. It must be kept in mind,
as discussed in more detailed above, that the dimensions recited
herein can vary substantially without affecting the anti-twist
capabilities.
[0044] It is believed that the extent to which the opening is
capable of inducing smoothing and urging actions on the webbing can
be measured by various aspect ratios, including the major to minor
height and width ratios and various other ratios (which can be
easily calculated from the dimensions provided above or scaled from
the attached figures).
[0045] The major to minor height ratio H.sub.1:H.sub.2, as shown,
is approximately 4:1, although a major to minor height ratio of
approximately 3:1 to 5:1 would also be sufficient. The major to
minor width ratio W.sub.1:W.sub.2, as shown, is approximately
1.17:1, although a major to minor width ratio of approximately 1:1
to 1.7:1 would also be sufficient. As the height and width ratios
approach 1, the opening is likely imparting more of an urging
action than a smoothing action on the webbing. In contrast, as the
height and width ratios approach infinity, the opening is likely
imparting more of a smoothing action than an urging action. In
addition or in alternative to providing the opening 40 with any
combination of the features described above, conforming the opening
40 of the retractor housing 10 to satisfy at least some of these
parameters will contribute to anti-twist capabilities of the
opening.
[0046] It is further believed that the anti-twist capabilities of
the shown embodiments are enhanced due to the dimensional
relationship of the opening height with the webbing thickness. For
comparison purposes, the thickness of typical webbing (or restraint
strap), is approximately 1.2 mm. When folded over into double
thickness and stitched together, the webbing will have a thickness
of around 2.4 to 2.5 mm. With H.sub.2 equal to 5.59 mm, it is
understood that the effective height of the opening, being slightly
greater than the thickness of double stitched webbing (about 2.2
times greater than a double stitched portion or about 4.7 times
greater than single thickness webbing), allows a double stitched
portion of webbing to pass into the opening. It has been found that
by closely conforming the height of the opening with the maximum
thickness of webbing in the manner described above (i.e., for the
shown embodiments, the thickness of a double stitched portion),
there is a reduced chance that an unintended folded over portion of
webbing will enter the retractor. It is believed that satisfactory
results can be obtained by reducing the effective height of the
opening such that it is less than ten times the thickness of the
webbing. It has been observed, however, that the ability of the
opening to resist the passing of twists exponentially increases by
decreasing the effective height of the opening, where the best
results can be obtained with an opening that has an effective
height which is approximately equal to the thickness of a double
stitched portion of webbing (i.e., approximately two times the
thickness of the webbing). Ideally, the opening will have an
effective height which is between approximately two (2) to six (6)
times the thickness of the webbing itself.
[0047] Referring now to FIGS. 7-12 and 14, a second embodiment of a
retractor 110 is shown. The second embodiment of the retractor 110
can be substantially similar to prior art retractors, in that it
comprises a housing 112 for enclosing and protecting the working
components of the retractor, including a spool mechanism 116, and
having a quadrangular opening 140 through which webbing 114 is
adapted to pass. Where the second embodiment of the retractor 110
differs from the prior art is its inclusion of a retrofit
anti-twist insert (or member) 145, which modifies the size and
shape of the opening 140 with the aim to reduce the chance that
twisted webbing will pass into the retractor housing 112. Although
the anti-twist insert 145 is designed to be easily installed by
end-users as an after-market component to provide pre-existing
retractor housings with anti-twist capability, other configurations
are contemplated which may require a skilled technician for
installation.
[0048] For practical reasons, the insert 145 is shaped like a "U"
and, therefore, has three sections 155, 175, 185. This construction
allows the insert piece 145 to be installed around the webbing,
thereby negating the need to disassemble the retractor and feed the
webbing through the insert piece. Although the convenience of a
three sided retrofit piece 145 is recognized herein, it is by no
means asserted that it would be impossible or prohibitively
difficult to utilize a four-sided piece or that the claims herein
do not cover such an embodiment. Indeed, it is contemplated that a
four-sided retrofit piece could be made which would require the
end-user (or maintenance personal) to disassemble the retractor 110
and feed the webbing 114 through the retrofit piece. Alternatively,
the retrofit piece could comprise two sections, one of which is
installed on one side of the webbing 114 and the other of which is
installed on the other side of the webbing 114. Yet another
alternative embodiment is shown in FIG. 18. The second embodiment
of the retrofit piece 345 is four-sided, having four sidewalls 350,
360, 370, 380, each of which could include a guide surface. One of
the sides 380 includes a cut 385, through which the webbing can be
inserted. Utilizing the elasticity of the retrofit piece 345, a gap
can be formed at the cut 385 by grasping the piece 345 from
opposite sides of the cut 385 and pulling in the directions
indication by the arrows in FIG. 18. When the piece 345 is
manipulated in such a manner, the opposite side 370 acts as a hinge
to allowing a gap to be formed at the cut 385, whereby the webbing
can be slid into the opening of the retrofit piece 345.
[0049] Referring again to the embodiment shown in FIGS. 7-12 and
14, the first embodiment of the retrofit insert piece 145 includes
at least one guide surface 150, which in the shown embodiment is
present on the upper section 155. It is contemplated that, in
combination or in the alternative, the side sections 175, 185 could
include similar guide surfaces. In addition, for a four sided
retrofit insert piece (not shown) one or more, or even all, sides
could include guide surfaces. See, for example, the guide surfaces
provided by the first embodiment of the retractor housing 10. It
should be noted that the particular housing 112 disclosed in the
figures includes an opening that is not sufficiently wide to
include guide surfaces on the side sections 175, 185. Inclusion of
guide surfaces on the side sections 175, 185 would reduce the width
of the opening to the point of buckling the webbing.
[0050] The guide surface 150 is shown as curvilinear and inwardly
converging, although it is contemplated that the guide surface
could be planar and/or discontinuous, just like the guide surfaces
50, 60, 70, 80 of the previous embodiment. As best shown in FIG.
11, the guide surface 150 has slopes that vary along its length
(i.e., along the direction of travel of the webbing) and, as shown,
has an inner portion 152 and an outer portion 154. Starting from an
inner extent of the inner portion 152 and moving outwardly, the
inner portion 152 begins as nearly parallel with the direction of
travel of the webbing (see FIG. 14) and gradually increases in
slope. In that respect, the upper guide surface 150 diverges from
the lower wall of the opening 140. The intersection 156 between the
inner portion 152 and the outer portion 154 is characterized by a
more substantial increase in slope along its length. The
intersection has an approximate radius of 0.14'', although the
radius could vary widely with similar results. The upper sidewall
150 continues to diverge from the lower wall of the opening 140
along the length of the outer portion 154, although to a much
greater extent. The outer portion 154 is marked by a gradual
increase in slope and, at an outer extent, approaches approximately
vertical. The outer portion 154 has a radius of approximately
0.13'' near its midpoint, although the radius could vary widely
with similar results.
[0051] In addition or in the alternative to changing the contour of
the opening 140, the insert piece 145 contributes to the untwisting
capabilities of the retractor housing 112 by modifying the aspect
ratios of the opening 140. Conforming the insert 145 to satisfy at
least some of the parameters provided above for the first
embodiment will contribute to anti-twist capabilities of the
opening.
[0052] The insert piece 145 includes multiple locking grooves 151,
172, 174, 182, 184 which are adapted to engage with the periphery
of the opening 140. In the shown embodiment, the locking groove
151, 172, 174, 182, 184 are essentially narrow channels which are
adapted to receive the thin-wall construction of the retractor
housing 112 which surrounds the opening 140. The first (or top)
section 155 of the insert piece 145 includes one generally
elongated locking groove 151 which is adapted to engage with the
upper wall of the opening 140. Both the second and third (or right
and left side) sections 175, 185 include two locking grooves 172,
174, 182, 184 which are adapted to engage with the side walls and
lower wall of the opening 140. The locking grooves 151, 172, 174,
182, 184 are generally bounded by an outer lip 157, 177, 187 and
inner lips 159, 179, 189. In the shown embodiment, the outer lip
157, 177, 187 continuously extends around the periphery of the
insert 145 and has outer dimensions which exceed that of the
opening 140. In that respect, the inside surface of the lip 157,
177, 187 rests against the outside surface of the retractor housing
112 and thereby frames the opening 140. The inner lips 159, 179,
189 are discontinuous to reduce the force required to install the
retrofit insert 145. However, it is contemplated that the outer lip
157, 177, 187 could be discontinuous and/or the inner lips 159,
179, 189 could be continuous.
[0053] As best shown by FIG. 12, the insert piece 145 is configured
to be installed, at least in part, by "snapping." First, the insert
piece 145 is tilted such that the upper locking groove 151 engages
with the upper wall of the opening 140. Then, the lower edge of the
insert piece 145 is rotated into engagement with the lower wall of
the opening 140. Moderate force may be required to snap the lower
and side edges of the insert piece 145 into engagement with the
opening. To reduce the required installation force, the inner lips
179, 189 have chamfered rear edges.
[0054] Although the insert component 145 is characterized as a
retrofit piece, and it was initially intended that it be used with
existing retractors to provide anti-twist capabilities, it is not
necessary that the retrofit piece 145 be used solely with
pre-existing retractors. Indeed, it is contemplated that the
retrofit piece 145 could be used or simply modified for use with
new and currently non-existing retractors. Alternatively, the
anti-twist inserts 145 can be installed into pre-existing guide
slots in barrier housings or other similar structures, to prevent
twisted webbing from passing into the barrier housing and becoming
wound onto a retractor spool.
[0055] Referring now to FIGS. 15-17, a third embodiment of a
housing 210 for a retractor is shown. The housing 210 is a
barrier-type housing, similar to that disclosed in U.S. patent
application Ser. No. 11/847,435, which houses multiple,
internally-mounted retractors for restraining a wheelchair and
wheelchair passenger. Specifically, two retractors are provided for
restraining a wheelchair from the rear side and three retractors
are provided for restraining a wheelchair passenger (i.e., by
providing lap and shoulder belts). The retractors include up to
several feet of webbing, which pass through a plurality of
anti-twist slots 220a, 220b, 230a, 230b, 240 in the housing, so
that they may be accessible for use. Each of the slots 220a, 220b,
230a, 230b, 240 include one or more anti-twist guide surfaces which
may be similar to those disclosed by the first and second
embodiments. Specifically, the anti-twist lap belt slot 220a (which
is similar, identical, or a mirror image of the anti-twist lap belt
slot 220b) includes a left sidewall guide surface 222a, a right
sidewall guide surface 224a, an upper sidewall guide surface 226a,
and a lower sidewall guide surface 228a. The anti-twist rear
wheelchair securement belt slot 230 (which is similar, identical,
or a mirror image of the anti-twist slot 230b) includes a left
sidewall guide surface 232a, a right sidewall guide surface 234a,
an upper sidewall guide surface 236a, and a lower sidewall guide
surface 238a. The anti-twist shoulder belt slot 240 is provided
with an upper side wall guide surface 242, a lower sidewall guide
surface 244, a left sidewall guide surface 226 and a right sidewall
guide surface 248. The anti-twist guide surfaces for the barrier
housing 210 can be provided with contours similar to any of the
above described guide surfaces and/or can cooperate to provide the
opening with any of the various aspect ratios defined above to
reduce the chance of twisted webbing from passing through the
slot.
[0056] Although the inventions described and claimed herein have
been described in considerable detail with reference to certain
embodiments, one skilled in the art will appreciate that the
inventions described and claimed herein can be practiced by other
than those embodiments, which have been presented for purposes of
illustration and not of limitation. Therefore, the spirit and scope
of the appended claims should not be limited to the description of
the embodiments contained herein.
* * * * *
References