Note: Descriptions are shown in the official language in which they were submitted.
IMPROVED AXILLARY CRUTCH
FIELD OF THE INVENTION
This invention relates to an improved axillary crutch with
improved balance, stability and weight-bearing capabilities to
enable persons with lower limb disorders to ambulate more easily.
BACKGROUND OF THE INVENTION
For persons with lower limb disorders (broken leg bones, leg-
muscle strains or pulls, knee injuries, broken foot bones, etc.)
there continues to be a need for improved axillary crutch designs
to make ambulation easier. There also continues to be a need for
improved axillary crutch designs having increased balance,
stability and weight-bearing capabilities.
Conventional axillary crutches, made in the so-called brace-
bow configuration, have a single tubular member extending down
from two substantially parallel tubular members, whereby a rubber
crutch tip fitted over the bottom of the single tubular member
comes into contact with the floor as the user ambulates. The two
substantially parallel tubular members are bowed at their lower
extremities and are there connected to the single tubular member.
All of the weight of the user is transmitted to the single tubular
member.
In such conventional crutches, the surface of the crutch tip
on the single tubular member which comes into contact with the
floor is flat. These crutches can become unstable as the user
applies rotative pressure to the crutch while ambulating. Also,
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; stated above, all of the user's weight is applied on the single
tubular member, resulting in a concentrated weight distribution
over a limited surface area. Further, the crutch tip at the
bottom of the crutch tends to become worn because pressure is
applied unevenly on the tip as the crutch is used. Overwear of
the crutch tip can cause safety problems during ambulation.
Further, adjusting the height of the crutch to better fit
the height of the user and adjusting the height of the handle on
the crutch to further accommodate the user involves two
independent and time-consuming steps on conventional crutches.
There remains a need for an improved axillary crutch which
allows for easier ambulation by persons with lower-limb disorders,
and provides increased balance, stability and increased weight-
bearing capabilities. There also remains a need for an easy-to-
use crutch height and handle adjustmen~ mechanism which allowsfor one-step adjustment of crutch height and handle height.
SUMMARY OF THE INVENTION
In one embodiment there is provided an improved axillary
crutch to aid ambulation comprising; an underarm bend section
designed for placement under the axilla of a user, the
underarm bend section having a top end, a bottom end and two
sides, the sides of the underarm bend section being in
substantially parallel relation to one another except at the
top end of the underarm bend section; a foot bend section
having a top end, a bottom radial end and two sides, the sides
of the foot bend section being in substantially parallel
relation to one another except at the bottom radial end of the
foot bend section, wherein the bottom radial end does not
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extend outwardly from the sides of the foot bend section and
wherein the bottom radial end comes into contact with the
floor during ambulation; a handle located intermediate the top
end of the underarm bend section and the bottom radial end of
the foot bend section; and means for inter-connecting and
securing the bottom end of the underarm bend section, the top
end of the foot bend section and the handle.
In more detail, the improved axillary crutch of the
present invention comprises two inter-connected hollow tubular
frame members. A bottom frame member has a bottom radial end,
the design of which, as noted above, is derived from the
natural arcing motion of the crutch during ambulation.
A top end of the bottom frame member telescopes into a
5 bottom end of a top frame member. A height and handle
adjusting means interconnects and secures a handle, the top
frame member and the
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_.ttom frame member. The handle in the height and handle
adjusting means has a central bore through which a bolt extends.
On either side of the crutch the bolt also extends through aligned
apertures in the top frame member and the bottom frame member. A
wing nut screwed on a threaded portion of the bolt is used to
secure the top frame member, the bottom frame member and the
handle together.
To adjust the height of the crutch relative to the floor, a
user or operator unscrews the wing nut, removes the bolt,
telescopes the bottom frame member to the desired position within
the top frame member and then reinserts the bolt into the properly
aligned holes in the top frame member and the bottom frame member.
The height of the handle relative to the crutch may also be
adjusted in the same step by moving the handle relative to the
top frame section and the bottom frame section after the bolt is
removed.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a front elevational view of an axillar~ crutch
of the present invention;
Fig. lA is an exploded view of the crutch of Fig. 1;
Figure 2 is a side view of the crutch of Fig. 1 along lines
2-2 of Fig. l;
Figure 3 is a detail view, partly in section, of a height
and handle adjustment means of the crutch of Fig. l;
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Figure 4 is an alternate embodiment for the height and handle
adjustment means of Fig. 3; and
Figs. 5-7 are perspective views showing the use of the
axillary crutch of the present invention by a user with a lower-
limb disorder.
DETAILED DESCRIPTION OF THE INVENTION
Referenee is made in this deseription by numbers to thevarious eomponents and sections of the axillary crutch of the
present invention. Like numerals in this description and in the
figures are understood to refer to like components and sections
of the erutch. It is to be understood throughout this application
that the term "axillary crutch" refers to a crutch which the user
places under his or her axilla or armpit area.
Fig. 1 shows in elevation an axillary crutch 10 of the
present invention. As with most axillary crutches, the crutch of
the present invention is best used in pairs, as shown in Figs. 5-
7. The second erutch 100 shown in Figs. 5-7 is identical in
eonstruetion to eruteh 10 and it is understood that the
deseription given below for eruteh 10 applies e~ually to crutch
100. Of course, the eruteh of the present invention may be used
alone or in pairs, depending on the needs of the user.
The eruteh 10 has two basic frame pieces as shown in the
figures - an underarm bend seetion 20 and a radial foot bend
seetion 30. Seetions 20 and 30 are each hollow tubular in
eonstruetion and made of aluminum in the present embodiment.
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Height and handle adjustment means 70, shown in detail in Figs. 3
and lA, interconnects sections 20 and 30 and provides for one-
step adjustment of the height of crutch 10 relative to the floor
and adjustment of the height of a handgrip 60 relative to the
crutch lO, as described below. An alternate embodiment 50 for
the height and handle adjustment means is shown in Fig. 4.
Underarm bend section 20 has a top end 21, on which an
underarm support 40 is secured as shown in Fig. lA. An underarm
pad 41 fits, as seen in Fig. lA, over the support 40. In the
present embodiment the pad 41 is made of a foam rubber material.
As seen in Figs. 5-7, to use the crutch lO, the user places the
pad 41 underneath his or her axilla or armpit area.
A bottom end of section 20 terminates in two hollow tubular
cross-section segments 22a and 22b, best seen in Figs. l and lA.
lS Segments 22a and 22b are parallel to one another and terminate at
the same vertical level, also as shown in Figs. l and lA. The
segments 22a and 22b contain equally-spaced apertures 24 for use
in securing the height and handle adjustment means 70 as described
below.
A top end of radial foot bend section 30 has two hollow
tubular cross-section segments 32a and 32b, best seen in Fig. lA.
Segments 32a and 32b, which are also parallel to one another and
terminate at the same vertical level, in the present embodiment
have less of a diameter than segments 22a and 22b and telescope
into the segments 22a and 22b of the underarm bend section 20 as
shown in Figs. l, 2 and 3. It is understood that crutch lO could
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also be designed such that segments 32a and 32~ have a diameter
greater than segments 22a and 22b and thus segments 22a and 22b
would telescope into segments 32a and 32b. As with segments 22a
and 22b the segments 32a and 32b contain equally-spaced apertures
34 for use in securing the height and handle adjustment means 70
as described below.
A lower end 31 of the section 30 is radial in shape, as
shown in Fi~s. 1, lA and 5-7. A crutch tip 33, also radial in
shape, made in the present embodiment of Santoprene~, a
thermoplastic rubber, is attached to the lower end 31 of the
section 30. Fig. lA shows the crutch tip 33 secured to the lower
end 31 of the section 30 by screws 33a, but it is understood that
any number of attachment means are suitable. Crutch tip 33 comes
in contact with the floor surface as the user ambulates, as shown
in Figs. 5-7.
The radial design of the lower end 31 of the section 30 is
derived from the natural arcing motion of the crutch 10 during
ambulation, and thus makes ambulation easier. As seen in Figs.
5-7, this radial design permits constant contact of a large part
of the surface area of the tip 33 with the floor through the full
range of ambulatory motion providing a more balanced, stable and
increased weight-bearing ambulation than with conventional crutch
designs. These advantages are derived in part because there is a
greater surface area of the tip 33 which is in contact with the
floor during ambulation compared to conventional crutch designs.
Also, unlike with conventional crutch tips, the conti~uous nature
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of the contact between the radial crutch tip 33 and the floor
prevents excessive wearing of any edge or portion of the tip 33,
increasing the useful life of the tip 33.
The radial design of the section 30 also aids in distributing
the user's weight more evenly during ambulation. Unlike
conventional crutches, where all of the user's weight is
distributçd at one location, the radial design of the crutch of
the present invention evenly distributes such weight, resulting
in less strain on the various components and also allowing the
user to ambulate more easily.
The details of the height and handle adjustment means 70 are
shown in Figs. 3 and lA. The means 70 includes a plastic handle
71 which extends from one side of the crutch 10 to the other. A
bolt 72 passes through a set of apertures 24 and 34 in sections
20 and 30, through a central opening in the handle 71, and then
through a second set of apertures 24 and 34. The bolt is secured
to the sections 20 and 30 by means of a wing nut 73 tightened on
a threaded portion 74 of the bolt 72. Handgrip 60 has a central
bore for receipt of the handle 71.
To change the height of the crutch 10 relative to the floor,
the user or operator unscrews the wing nut 73 and then removes
the bolt 72 from the handle 71. The segments 32a and 32b may then
be telescoped further into or further out of segments 22a and 22b
by the user or operator until the desired vertical height for the
crutch 10 is reached.
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The user or operator then aligns apertures 24 and 34 as
required, inserts the bolt 72 through one set of aligned apertures
24 and 34, through the central bore in the handle 71 and then
through another set of aligned apertures 24 and 34 on the other
side of the crutch 10. To secure the height and handle adjustment
means 70, the user or operator tightens the wing nut 73 on the
threaded portion 74 of the bolt 72.
The height of the handgrip 60 relative to the crutch 10 may
also be changed by unscrewing the wing nut 73 and removing the
bolt 72 in the manner described above. The handgrip 60 and the
handle 71 within it are then moved to a different set of aligned
apertures 24 and 34 and the bolt is reinserted through the new
apertures 24 and 34 and secured to the sections 20 and 30 by
means of the wing nut 74 in the manner described above.
In the present embodiment the handgrip 60 is made of a foam
rubber material. The handgrip 60 is designed to reduce hand
fatigue by dispersing loads over a larger surface area than
typical crutches during ambulation.
The height of the crutch 10 of the present invention can be
adjusted to accommodate users between the heights of 5'0" and
6'5". The telescoping of the radial foot bend section 30 into
the underarm bend section 20 allows for this wide range of
adjustment.
In conventional crutches, such as the brace-bow configuration
described above, height adjustment of the crutch is much more
limited because if the singular tubular member in such crutches
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is too long, the added torque developed can cause instability
during ambulation. Further, the increased torque can cause
unwanted structural stress on the crutch components, especially at
the point where the single tubular member is connected to the
bowed upper tubular members.
To avoid the problems described above, manufacturers of
conventional axillary crutches usually provide two separate crutch
models, one for shorter persons and one for taller persons. The
crutch lO of the present invention is designed to accommodate
1~ users of widely-varying heights so that one model may be used by
almost any person, regardless of height.
The details of the alternate embodiment 50 of the height and
handle adjustment means are shown in Fig. 4. The means 50
includes a handle Sl with a top half section 51a and a bottom
half section 51b. In this alternate embodiment each handle
section 51a and 51b is made of acrylonitrile buladiene styrene
(ABS). Sections 51a and 51b of the handle 51 are connected
together by mechanical means, such as screws 54 shown in Fig. 4,
though it is readily understood that other suitable fastening or
connecting means may be used.
Retractable pins 52a and 52b are located at the outer ends
of shafts 55a and 55b, respectively, within handle 51. Shafts 5Sa
and 55b run through the center of the handle 51 as shown in Fig.
4. Spring 56, wound around shafts 55a and 55b as shown in Fig.
4, ensures that pins 52a and 52b are normally in the loaded
position, i.e. will engage in the aligned apertures 2~ and 34 of
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sections 20 and 30 to secure the handle 51 to the sections 20 and
30 at the desired location.
To change the height of the crutch 10 relative to the floor
for this alternative embodiment, the user or operator rotates
lever 57 on handle 51 in the direction of the arrow of Fig. 4 to
the position shown by the dotted lines in Fig. 4, causing nylon
cam 58 in handle 51 to release the spring loading on pins 52a and
52b, thus retracting pins 52a and 52b on shafts 55a and 55b from
engagement in the apertures 24 and 34. The segments 32a and 32b
may then be telescoped further into or further out of segments
22a and 22b by the user or operator until the desired vertical
height for the crutch 10 is reached. The user or operator then
rotates the lever 57 back to its secured position, in the
direction opposite to the arrow in Fig. 4, causing the spring 56
to once again direct an outward load on the pins s2a and 52b and
thus causing pins 52a and 52b to be securely engaged in the
aligned apertures 24 and 34 at the location desired.
The height of the handle 51 relative to the crutch lo may
also be changed by releasing lever 57 in the manner described
above and sliding handle 51 to a different set of apertures 24
and 34 relative to the sections 20 and 30.
Designed to fit over the handle 51 is a contoured handgrip
(not shown). In this alternative embodiment the handgrip is also
made from a foam rubber material, the same as in the Fig. 3
embodiment.
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As shown above, the handle and height adjustment means of
Figs. 3 and 4 each allow for one-step adjustment of both crutch
height relative to the floor and handle height relative to the
crutch. This is a simpler and faster procedure than for
S conventional crutch designs which normally employ a two-step
system for adjusting crutch height and handle height. Expedited
sizing of the crutch benefits the user of the crutch 10 as well
as benefiting the therapist or hospital personnel assigned to the
task of properly fitting the crutch to a user.
Because the crutch 10 of the present invention does not have
the conventional brace bow design, the risk of injury from cut
ends of tubing is reduced. Also because there is only one
mechanism for both crutch-height and handle-height positioning,
the risk of injury from sharp edges of fasteners or connectors is
also reduced.
It is understood that the present invention is not limited
to the embodiment described above but is defined by the following
claims.
