Patent Description:
Numerous types of crutches are known for providing mobility to those who suffer from infirmities, injuries, and/or handicaps. Hands-free crutches are particularly useful because they allow their users to use both hands for tasks other than stabilizing the crutch.

The earliest hand-free crutches appear to have relied on monopods, i.e., a single ground contact pad that is substantially flat on the bottom. See e.g., <CIT>) and <CIT>). That strategy has persisted into the present, as exemplified by <CIT>), <CIT>), <CIT>), <CIT>), <CIT>), and <CIT>).

These and all other extrinsic materials discussed herein are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

Starting in the mid-<NUM> three appears to have been recognition that a single foot was not satisfactory, and the field began experimenting with use of a second foot. See e.g., <CIT>), <CIT>). Other variations to improve stability have included a single foot having a width that extends from the medial to the lateral side of the user's foot, and even a three-footed crutch, see the Freedom Leg™ (<NUM>) and <CIT>), respectively. Other similar crutches can be found in prior art documents <CIT> and <CIT>.

Unfortunately, these and all other known hands-free crutches are difficult to use due to lack of stability and/or lack of natural transfer of weight. The user must re-learn a new way of transferring weight to and from the crutch while walking. Thus, there is still a need for stable hands-free crutch, which allows the user to walk in a relatively natural manner.

The inventive subject matter provides apparatus, systems, and methods in which a hands-free knee crutch provides stable and natural weight transition by providing a ground support in which (<NUM>) a medial contact region is higher than a lateral contact region when weight is being transmitted vertically to the ground or other surface, and (<NUM>) both the medial and lateral contact regions touch the surface when weight is being transmitted to the surface at some functional angle off vertical.

The medial and lateral contact regions can be positioned on one or more feet, but are preferably positioned on a single foot. Since the ground support is slightly supinated, the foot or feet is/are preferable rotatable relative to the knee platform to accommodate either left or right leg usage. The foot (or lateral foot where there are two feet) also preferably has a symmetrically curved lateral edge.

In especially preferred embodiments the medial and lateral contact regions are disposed on medial and lateral pads, respectively, which can advantageously be configured as sagitally oriented rockers. In a rocker configuration, anterior and posterior ends of the pads are curved upwards relative to the middle. Pads can be part of a unitary whole, but are preferably separate components, separated by at least <NUM>, more preferably at least <NUM>, more preferably at least <NUM>, more preferably at least <NUM>, more preferably at least <NUM>, and most preferably at least <NUM>. Even wider separations are also contemplated, depending in part on the width of the foot and the width of the pads. The pads and/or treads on the pads can be user replaceable.

The extent to which the medial contact region can be higher than the lateral portion when weight is being transmitted vertically to the surface is between <NUM> and <NUM>, more preferably between <NUM> and <NUM>, and most preferably between <NUM> and <NUM>. In some contemplated embodiments that difference can be adjusted by the user.

Preferred leg supports are significantly different from others on the market. In one aspect the leg platform can have a posteriorly narrowing "V" or "U" shaped support. In another aspect, preferred crutches include a knee fastener that pulls the knee anteriorly and inferiorly. In another aspect, preferred crutches include a thigh fastener that couples to an at least partially rigid thigh contact, which provides additional lateral support and alignment of the frame. Most preferably the thigh contact is part of an upper thigh saddle having both inner and outer thigh contacts. As used herein a "knee strap" is a knee fastener that pulls the knee anteriorly and inferiorly.

In addition to the usual strap and height adjustments, preferred embodiments include: (<NUM>) adjustment for the thigh saddle or other contact; (<NUM>) relative height adjustments for the medial and lateral contact regions of the foot or feet; and (<NUM>) replaceable treads on medial and lateral pads of the foot or feet.

The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.

The prior art failed to appreciate a critical feature of crutches; that when used by the average person, weight passing through the supported leg will generally be directed off vertical. The current inventor took that one step further, recognizing that the foot (or feet) of a crutch should therefore have a medial contact region that is raised relative to a lateral contact region when weight is being transmitted vertically to the ground or other horizontal surface. These distinctions are readily apparent by viewing <FIG>.

In <FIG> a flat-bottomed foot <NUM> of a lower portion of hands-free crutch <NUM>, is pushing against the ground <NUM>. The weight of a user (not shown) is being transmitted vertically through a post <NUM> to the ground <NUM> as shown by force line 14A. Assuming this crutch is being used on a right leg, then viewed from the rear there is a medial contact region <NUM> on the left and a lateral contact region <NUM> on the right, coupled together to form a single pad. Medial contact region <NUM> and lateral contact potion <NUM> contact the ground <NUM> at the same time.

In <FIG> the flat-bottomed foot <NUM> of <FIG> is pushing against the ground <NUM> at an angle shown by force line 14B. Here the medial contact region <NUM> is touching the ground <NUM>, but the lateral contact region <NUM> is off the ground <NUM>.

A similar situation occurs with a rounded foot. In <FIG> a rounded, conventional crutch foot <NUM> of a lower portion of a crutch <NUM>, is pushing against the ground <NUM>. Since the rounded foot has some flexibility, and assuming this crutch is being used on a right leg, there is still a medial contact region <NUM> and a lateral contact region <NUM>. The weight of a user (not shown) is being transmitted vertically to the ground <NUM> as shown by force line 24A. Here, the medial contact region <NUM> and lateral contact region <NUM> are contacting the ground <NUM> at the same time.

In <FIG> the rounded, conventional crutch foot tip <NUM> of <FIG> is pushing against the ground <NUM> at an angle shown by force line 24B. Here the medial contact region <NUM> is touching the ground <NUM>, but the lateral contact region <NUM> is off the ground <NUM>.

In an embodiment of <FIG> according the inventive subject matter herein, foot <NUM> of the lower portion of hands-free crutch <NUM>, is pushing against the ground <NUM>. The weight of a user (not shown) is being transmitted vertically to the ground <NUM> as shown by force line 34A. Assuming this crutch is being used on a right foot, there is a lateral contact region <NUM> that is touching the ground, and a medial contact region <NUM> that is currently raised above the ground <NUM>.

In <FIG> the foot <NUM> of <FIG> is pushing against the ground <NUM> at an angle shown by force line 34B. Here both the medial contact region <NUM> and the lateral contact region <NUM> are touching the ground <NUM> at the same time.

<FIG> are similar to <FIG>, except that here the lower portion of hands-free crutch <NUM> has two feet <NUM> and <NUM>. Assuming this crutch is being used to support a user's right leg (not shown), the lateral contact region <NUM> is on the right of foot <NUM>, and the medial contact region <NUM> is on the left foot <NUM>. In <FIG> the force line 44A is vertical, and the medial contact region <NUM> is elevated while the lateral contact region <NUM> is touching the ground. In <FIG> the force line 44B is at an angle off vertical, so that both the lateral contact region <NUM> and the medial contact region <NUM> are touching the ground <NUM> at the same time.

The minimum angle off vertical at which both lateral and medial contact regions will touch the ground is referred to herein from time to time as the critical angle, and will depend on how several factors, including far apart the two weight bearing pads (or feet) are located, and the relative height of the more medial one when the force line is vertical. Contemplated critical angles include <NUM>-<NUM>°, <NUM>-<NUM>°, <NUM>-<NUM>° and <NUM>-<NUM>°. In general, the critical angle will be between <NUM>° and <NUM>°, although both lesser and greater angles are contemplated.

The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. The use of any and all examples, or exemplary language (e.g. "such as") provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention. Unless otherwise expressly stated, all ranges include their endpoints.

As shown in <FIG>, the medial ground contact region acts as a counterbalance to the lateral ground contact region. In general, the greater distance between the medial and lateral ground contact regions, the higher the medial ground contact region should be above the lateral ground contact region. And yet, these distances should not be very great. If user is walking with the crutch using a slight abduction, then simultaneous ground contact will occur with each step unless the user missteps.

Although two ground contact regions seems to work the best, it should be appreciated that one could have more than two such regions. In addition, the total are of all regions of ground contact can be fairly large. In preferred embodiments that total is at least <NUM><NUM>, more preferably at least <NUM><NUM>, more preferably at least <NUM><NUM>, and in some embodiments at least <NUM><NUM>. <FIG>, 3C and 3D should be interpreted as having a total area of ground contact of at least <NUM><NUM>.

In <FIG> a crutch <NUM> generally comprises a frame <NUM>, to which are coupled a thigh fastener <NUM>, a thigh saddle <NUM>, a handle <NUM>, a leg platform <NUM>, and a foot <NUM>.

The frame <NUM> generally comprises two upper supports 112A, 112B, two lower supports 114A, 114B, and a post <NUM>. The thigh fastener <NUM>, thigh saddle <NUM>, handle <NUM> and leg platform <NUM> are all connected directly to the two upper supports 112A, 112B. The post <NUM> is connected to the leg platform <NUM>, the lower supports 114A, 114B and the foot <NUM>. The frame members are preferably aluminum to provide sufficient strength with relatively low weight. All suitable materials are also contemplated, including steel, composites, rigid plastics, which could be extruded to include an internal I-beam for strength.

The two upper supports 112A, 112B are preferably telescoping, and include locks 113A and 113B, respectively. The thigh fastener <NUM> preferably comprises a plastic, including for example nylon or polyester webbing, or other strap <NUM>, which can be tightened at fastener <NUM>.

The thigh saddle <NUM> generally comprises a left arm 132A and a right arm 132B, which are at least partially rigid, and extend out from mechanisms 134A and 134B respectively. Those mechanisms force the arms to extend either more directly backwards above the leg platform <NUM> to accommodate a relatively narrow thigh, or further apart from each other to accommodate a relatively wider thigh. Because of their rigidity, the left and right arms 132A, 132B help stabilize the crutch <NUM> relative to the thigh. In preferred embodiments, the arms can be adjusted independently, allowing proper vertical alignment of the crutch for a wide range of leg geometries. The mechanisms 134A, 134B can be any suitable mechanisms for achieving the purposes described herein, an in the relevant figures are merely screws 136A, 136B that tighten ratchet teeth (only partially shown as 138A, 138B) against one another.

It should also be appreciated that much of the stabilization provided by thigh saddle <NUM> can be provided by an at least partially rigid inner thigh arm operating by itself, i.e., without cooperation of a lateral arm.

Lateral adjustability of the inner thigh member should be interpreted as adjustability relative to the leg platform, and can be accomplished in many different ways. One way is to provide rotation of the inner thigh member using a mechanism as shown in <FIG>. Another way is to provide an inner thigh member that is telescoping, or has an extension. Another way is to provide replaceable inner thigh members of different geometries. Another way is to support the inner thigh member on a carriage with transverse adjustments. Still another way is to provide a frame mount of the inner thigh member that is adjustable. Still another way is provide the leg platform with lateral mobility.

The same adjustment mechanisms could apply to an outer thigh member.

As used herein, the term "at least partially rigid" with respect to an object means that a <NUM> length of the object cannot be bent under normal operating conditions (STP) by more than <NUM> without permanently deforming the object.

Although not shown in the Figures, an alternative thigh saddle could move laterally relative to the frame. The key is that no matter how the thigh saddle is structured, it should have sufficient rigidity to constrain crutch movement at the upper thigh, yet can be adjustable to have proper placement on thighs of different sizes and shapes.

Handle <NUM> is also preferably stiff plastic, but could also be wood, metal or some other material. Experiments have shown that handle <NUM> is important for some new users to gain confidence in using the device. However, due to the many other novel features discussed herein, most new users find the handle unnecessary after only a few minutes of practice. The handle can also be used for short trips when the user does not want to take time to strap in, and for long trips to combat leg fatigue.

As shown, handle <NUM> is positioned medially relative to a front perspective of the frame, rather than being placed on one side of the frame as in prior art devices. Medial positioning is considered herein to be advantageous because it facilitates use in standing up from a seated position, and facilitates use of the crutch as a cane. Although a handle need not be placed exactly in a medial sagittal line of the crutch, it is preferred that the handle be positioned such that a medial sagittal plane of the crutch passes through at least a portion of the handle. As used herein, the medial sagittal plane of a crutch is to be taken as the vertical plane that passes through the leg platform along a user's lower leg when the leg is fastened into the crutch for walking.

In the crutch of claim <NUM>, the top of the handle is positioned at an approximate top of the frame. This is also not an absolute requirement. It is, however, preferred that the top of the handle be positioned within <NUM> of the top of the frame, more preferred that the top of the handle be positioned within <NUM> of the top of the frame, and most preferred that the top of the handle be positioned within <NUM> of the top of the frame.

Contemplated handles need not have any particular ergonomic shape. Contemplated handles include padded bars as show in <FIG>, <FIG>, <FIG>, and <FIG>, as well as more knob shaped handles (not shown). Contemplated handles may or may not be padded, and may or may not have a leather or other coating.

In <FIG>, <FIG>, <FIG>, and <FIG>, the handle should be interpreted as being integral with the thigh saddle.

Leg platform <NUM> has a support <NUM> sized and dimensioned to receive one of the lower legs of the user, with the knee facing forward and the user's foot facing rearward. Since the knee of many people is wider than the anterior (bony) portion of the lower leg, the knee (forward) portion of the support <NUM> is wider than the more rearward portion of the cushion <NUM>. Further, as the support transitions from anterior to posterior, the U shape similarly transitions to more of a V shape to better conform to the contours of the human leg. This provides additional proprioception, stability and control of the crutch.

A rear strap <NUM> and rear fastener <NUM> keep the mid portion of the user's lower leg snug against the cushion <NUM>, while a forward strap <NUM> and forward fastener <NUM> keep the upper portion of the user's lower leg snug against the cushion <NUM>. The forward strap <NUM> is preferably coupled to the leg platform <NUM> quite close to the upper supports 112A, 112B, such that the strap can actually contact the user's leg at or near the popliteal fossa, and tend to pull the leg down against both the cushion <NUM> and forward against a blocking band <NUM> configured between the two upper supports 112A, 112B. The blocking band <NUM> stops the knee from pushing forward in the space between the two upper supports 112A, 112B.

As used herein, and unless the context dictates otherwise, the term "coupled to" is intended to include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). Therefore, the terms "coupled to" and "coupled with" are used synonymously.

Post <NUM> is preferably telescopic, with holes 116A and at least one pin 116B to maintain a desired relationship between the moving telescoping parts. Adjustment of the effective length of post <NUM> allows for operation of the crutch <NUM> with users having very different leg lengths.

<FIG> is a perspective view of the crutch of <FIG>, in which the foot is oriented for use in supporting a left leg.

Foot <NUM> is as described above with respect to <FIG>, and shown in <FIG>. However, as perhaps more clearly seen in <FIG>, foot <NUM> has two pads <NUM> and <NUM> that correspond to the medial and lateral contact regions, respectively. Each of the pads <NUM>, <NUM> is has a rocker configuration, having a convexity facing the floor or other surface, and oriented to rock in an at least approximately sagittal direction. In this particular embodiment the pads <NUM>, <NUM> have user replaceable treads <NUM>, <NUM>. Any suitable mechanism can be used to ensure that the bottom of the more medial pad <NUM> is raised relative to the bottom of the more lateral pad <NUM>, including a shim <NUM>, placed above the more lateral pad <NUM>. Relative height can also be adjusted using adjusting screws <NUM>.

The two pads <NUM> and <NUM> are preferably spaced apart by a distance X. X is preferably between <NUM> and <NUM>, more preferably between <NUM> and <NUM>, and most preferably between <NUM> and <NUM>. Since the pads <NUM> and <NUM> each have width, the distance between the pads is taken between the centers of the bottom-most regions of each of the pads when the user's weight is directed vertically downward. Where one or more pads are curved, there are of course multiple centers, and the distance between the pads is taken between the furthest apart centers.

Foot <NUM> can be oriented for use with support of a user's left or right foot merely by rotating the foot <NUM>° relative to the post <NUM>, or rotating both the foot <NUM> and an inner portion of the post <NUM> relative to the leg platform <NUM>. To that end foot <NUM> has a curved lateral edge <NUM>, with symmetry such that the foot <NUM> works equally well, and looks similar, in both left leg and right leg configurations.

<FIG> is a rear view of a person <NUM> having a left leg <NUM> and a right leg 105R. In this example the person is using the crutch of <FIG> to support his left leg 205R, where the user's weight is being transmitted vertically to the ground. <FIG> is a rear view of a person using the crutch of <FIG> to support his left leg, where the user's weight is being transmitted at an angle off vertical.

Two additional features are readily apparent from <FIG> and <FIG>. First, in <FIG>, where the user's weight is pushing vertically down against the ground or other surface <NUM>, a median sagittal vertical plane <NUM> between the medial and lateral contact regions (in this case medial contact region <NUM> and <NUM>) is laterally positioned from a median sagittal vertical plane <NUM> of the leg platform <NUM> by an offset Y of at least <NUM>. Y is preferably at least <NUM>, more preferably at least <NUM>, but not more than <NUM>. Here again, since the pads <NUM> and <NUM> each have width, the median between the pads is taken between the centers of the bottom-most regions of each of the pads when the user's weight is directed vertically downward.

Second, in <FIG> the medial contact region <NUM> and is raised relative to the lateral contact region <NUM> by a distance Z. Z is preferably at least <NUM>, more preferably at least <NUM>, but not more than <NUM>. The lateral contact region <NUM> is touching the ground.

<FIG>show yet another embodiment, in which a crutch has a foot <NUM> with only a single ground contact region <NUM>. In these instances the bottom <NUM> of the foot has a proper camber to accommodate abduction of the user's supported leg, and what could be considered the lateral ground contact region <NUM> is continuous with the medial ground contact region <NUM>. When applying the claims to this type of embodiment, the height difference between medial ground contact region and the lateral ground contact region, and the separation between those regions, should be calculated using the medial most edge of the bottom <NUM> and the lateral most edge of bottom <NUM>.

Astute readers will appreciate that as with other figures, <FIG> depict the height of medial ground contact portion <NUM> relative to the lateral ground contact <NUM>, and the angles at which force lines are directed to the ground <NUM>, in an exaggerated fashion for ease of viewing, and should be interpreted according to the angles given in the specification. More accurate representations are shown in <FIG> and <FIG>. Force line 274A should be interpreted as being vertical.

Claim 1:
A crutch (<NUM>) comprising:
a frame (<NUM>)
an upper leg restraint (<NUM>) coupled to the frame;
a laterally adjustable, at least semi-rigid, thigh member coupled to the frame, and
configured to facilitate alignment of the crutch with respect to a user's leg,
wherein the thigh member comprises a first (132A) at least partially rigid arm and a second (132B) at least partially rigid arm;
mechanisms (136A, 136B) for independently adjustable restriction of rotational movement of an end of
each of the first and second at least partially rigid arms (132A, 132B) relative to the frame (<NUM>); and
a lower leg platform (<NUM>) coupled to the frame (<NUM>)