WHITE CANE DEVICE FOR THE VISUALLY IMPAIRED THAT REDUCES SCANNING EFFORT

Abstract

WHITE CANE DEVICE FOR VISUALLY IMPAIRED PERSONS REDUCING SCANNING EFFORT The invention relates to a white cane, a locomotion device for visually impaired persons, comprising a tip consisting of at least two wheels of the same diameter of a few centimeters having a common axis of rotation called the wheel axis and spaced a few centimeters apart; a second axis of rotation, in an almost vertical direction, when the cane is held by the user, called the pivot axis, located a few centimeters in front (in the direction of movement of the person) of the wheel axis, and being midway between the planes of the two wheels, the pivot axis allowing the end of the cane to rotate relative to the block consisting of the tip containing the wheels; a means of locking the different segments constituting the cane so that they cannot rotate relative to each other along the axis of rotation constituted by the cane axis.Figure to be published with the abbreviation: [Fig 1].

Description

Title of the invention: WHITE CANE DEVICE FOR THE VISUALLY IMPAIRED REDUCING THE SWEEPING EFFORT TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of aids to locomotion for visually impaired people and in particular long white canes intended to secure the state of the ground when moving around.

[0002] The present invention relates to a white cane structure making it possible to reduce the efforts of visually impaired people at the wrist, arm and hand level during the sweeping movement of the cane to explore the ground, and this particularly in the case of rough ground. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] In order to allow the visually impaired person to ensure that the state of the ground in front of their feet will not cause them to lose their balance, a long white cane is used. The white color is a signal code. The length of the cane depends on the height of the person, typically it corresponds to the height of the sternum, for example approximately 1.3 m for a person measuring 1.7 to 1.75 m. The visually impaired person holds their cane in their hand, positioned at navel level. They must keep the tip of their cane in contact with the ground, while performing a lateral right-left sweep, by flexion-extension of the wrist. This sweep must allow the tip of the cane in contact with the ground to describe an arc curve whose width, in the direction perpendicular to the step, corresponds approximately to the width of the shoulders. This arc curve must be centered in relation to the axis of the step so as to optimize the protection of the ground.

[0004] The tip of the white cane is the part in contact with the ground. On rough surfaces, the tip easily catches and makes sweeping the cane difficult. This encourages users to lift the cane and only touch the ground at the ends of the sweep (called the two-step technique). The dips between the two ends of the sweep are not detected, and safety is not ensured.

[0005] To ensure that the tip of the cane remains in permanent contact with the ground, reducing snags, rolling tips have been developed. These are balls or cylinders, a few centimeters in diameter, rotating around an axis of rotation that corresponds to that of the cane. All current so-called "high-end" models of canes have rolling tips.

[0006] More recently, a spring has been added between the end of the cane and the rolling tip to further reduce the tip's snagging on the ground, causing it to bounce off certain rough spots instead of getting stuck there.

[0007] Rolling tips have improved the grip of the cane tip on the ground, which has improved safety. However, wrist tendonitis remains very common among white cane users. In cases of very rough ground, users still tend to lift the cane to relieve the strain on the wrist. In order to reduce the strain, the hand is often off-center and placed to the side instead of being centered in relation to the body (finding itself at hip level rather than at navel level in normal use), the wrist movement is then replaced by an arm movement. These common practices cause the cane to lose its symmetry and centering on the ground and reduce the protection of the person on one of their sides (depending on the direction of the asymmetry).

[0008] The movement of the tip of the cane on the ground is composed of a lateral sweeping movement combined with a forward movement of the tip in the direction of movement of the person (or longitudinal). The tip whose axis of rotation is that of the cane allows only lateral rotation and grips the ground for the longitudinal component going in the direction of movement of the person. Other types of tips have been proposed but are not commonly used. For example, a wheel is proposed whose axis of rotation is perpendicular to that of the cane. This tip allows one to move forward with ease on rough ground provided that the cane is not swept because only movement in the direction of movement of the person is permitted. To introduce a lateral component to the sweep, a pronation-supination movement of the wrist must be made, tilting the wheel relative to the ground.This movement is difficult to control physiologically, which makes the sweep unstable, the wheel easily lying on the ground and then blocking the person's progress. Tips containing more complex rotation systems in both axes have been proposed. They pose two problems, greater friction, a greater possibility of becoming clogged with mud and dust on the ground, as well as a small radius of curvature for one of the directions of rotation, which makes it stick to the ground.

[0009] There is a need to further reduce the snagging of cane tips on the ground in order to reduce the difficulty of using the white cane as a mobility tool. In addition, current tips do not promote centering of the cane's grip, and do not help to make the sweep symmetrical. An off-center or asymmetrically sweeping cane very often requires less physical effort from the user at the expense of their safety. It is useful for the structure of the cane to promote the symmetry of the sweep. Summary of the invention

[0010] The invention offers a solution to the two problems mentioned above, namely on the one hand considerably reducing the effort required to sweep the cane on rough ground compared to the rotating tips currently in use, and on the other hand making the sweeping effort minimal when the latter is symmetrical with respect to the axis of the step in order to promote the safest mode of use of the cane.

[0011] Throughout the rest of the text, the longitudinal axis is that of the person's movement and the lateral axis is the axis perpendicular to the longitudinal axis. The white cane is usually composed of segments which fit into each other and the segment at hand level is equipped with a sleeve of larger diameter facilitating the grip. The tip of the cane is connected to the end of the segment closest to the ground. For a folding cane, the segments are held together by an elastic band passing inside them. For a telescopic cane, the segments of decreasing diameters starting from the sleeve slide into each other.

[0012] The invention relates to a white cane, a locomotion device for visually impaired people, comprising • a tip consisting of at least two wheels of the same diameter of a few centimeters having a common axis of rotation called the wheel axis and spaced a few centimeters apart; • a second axis of rotation, of almost vertical direction, when the cane is held by the user, called the pivot axis, located a few centimeters in front (in the direction of movement of the person) of the axis of the wheels, and being halfway between the planes of the two wheels, the pivot axis allowing the end of the cane to rotate relative to the block consisting of the tip containing the wheels; • a means of locking the different segments constituting the rod so that they cannot rotate relative to each other along the axis of rotation constituted by the axis of the rod.

[0013] The flexion-extension movement of the wrist moves the almost vertical pivot axis located in front of the wheel axis. This offset between the pivot axis and the wheel axis is called caster offset. This effect allows the wheels to constantly follow the path of movement of the pivot axis, which minimizes resistance to forward movement, particularly on rough ground. Indeed, a conventional cane tip rolling only laterally produces additional resistance to roughness in the longitudinal direction because there is no rotation in this direction.

[0014] Having two parallel wheels on the same axis with a distance between the two wheels allows stability of the tip on the ground which will not spontaneously lie on its side by rotation around the axis of the cane as a single wheel would do. The tip being stable on the ground, the locking of the segments makes it possible to prohibit pronation-supination movements of the wrist during the scanning process. Scanning by an exclusive flexion-extension movement allows a better perception of the direction of the cane.

[0015] The wheels rotate freely relative to each other about their common axis of rotation. This makes changes in direction of the rod smoother, with one wheel then having a different rotational movement than the other.

[0016] The rotation of the segments of the cane around the axis of the cane is prevented by male-female type locking pieces fixed to the ends of the segments in order to fit together, eliminating the degree of freedom of rotation. This connection blocking the degree of freedom of rotation is done for example on the tenon-mortise principle.

[0017] In addition to the characteristics which have just been mentioned in the preceding paragraph, the device according to the invention may have one or more complementary characteristics among the following, considered individually or according to all technically possible combinations.

[0018] Both wheels are identical and covered with an abrasion-resistant polyurethane rubber.

[0019] The rotations around the axles for the wheels are ensured by sealed ball bearings.

[0020] Rotation around the pivot axis is provided by a sealed ball bearing.

[0021] The almost vertical pivot axis is connected to the end of the cane by an elbow at approximately 45° (between 30° and 60°), for a standard length of cane, the latter is generally inclined at an angle close to 45° relative to the ground. If this is not exactly the case depending on the ratio of the person's height to the length of the cane, the pivot axis will not be exactly vertical, but deflected by the same amount. The correct operation of the device does not require a strictly vertical axis. According to an alternative embodiment it is also possible to decide to have an angle somewhat different from 45° between the pivot axis and the axis of the cane, without affecting the correct operation.

[0022] The end of the cane and the base of the tip include stops which will limit the amplitude of rotation around the pivot axis by more or less 50° for example (the chosen limit can be between 30° and 90°), 0° corresponding to the position where the axis of the cane is parallel to the plane of the wheels. The advantage is, on the one hand, to systematically have the pivot axis in front of that of the wheels when starting, on the other hand to have a blocking of the rotation of the wheels if the sweep is asymmetrical and is done on one side with excessive amplitude.

[0023] A flexible rubber seal of the "silent bloc" type with a diameter close to that of the rod, a few millimeters long, is added to the end of the rod before the tip in order to absorb shocks when the tip hits a rising curb of the sidewalk, for example.

[0024] The cane knob or sleeve contains a flat or other means of identification so that visually impaired people can immediately know, when holding the sleeve, how the wheels are positioned in space. This allows the user to start by having both wheels directly positioned in the horizontal plane, without having to turn the cane until finding the position where both wheels are flat in the right direction.

[0025] The lengths of the different segments of the cane are identical, so that all of the folded segments are in continuity with the tip in order to respect the standard size of the folded cane.

[0026] According to an alternative embodiment, it is possible to multiply the number of wheels on the wheel axle or to have very wide wheels to have a tip which can move forward in soft ground.

[0027] According to an alternative embodiment, a negative camber angle of a few degrees (less than 20 degrees) can be introduced between the two wheels in order to promote rotation when the sweep changes direction.

[0028] The front end of the cane has a plane inclined from top to bottom, the bottom being set back from the top, in order to facilitate crossing the stops.

[0029] This type of device can be adapted to telescopic rods, the only difference is that the segments will fit into each other instead of being folded while being held by an elastic band. BRIEF DESCRIPTION OF THE FIGURES

[0030] The figures are presented for information purposes only and in no way limit the invention. • [Fig.l] shows a schematic representation of the entire cane. • [Fig.2] shows a schematic representation of the detail of the cane tip in perspective. • [Fig.3] shows a schematic representation of the cane tip viewed from below. • [Fig.4] shows a schematic representation of the cane tip viewed from above. • Figures 5a and 5b show an example of locking the rotation of the rod segments along the axis of the rod. DETAILED DESCRIPTION

[0031] The figures are presented for information purposes only and in no way limit the invention.

[0032] Unless otherwise specified, the same element appearing in different figures has a single reference.

[0033] The invention relates to a long white cane minimizing sweeping efforts and promoting optimal symmetrical sweeping for safety.

[0034] The device is a white cane for the visually impaired as shown in Figures 1, 2, 3, 4, 5a and 5b.

[0035] The term "relief on the ground surface" or "roughness" means a point on the ground surface having a height different from the height of a theoretical reference surface line, corresponding to flat ground.

[0036] [Fig.l] shows a schematic representation of the complete cane comprising its segments 1 and its tip 2.

[0037] [Fig.2] shows in perspective the tip of the cane in contact with the ground. The axis of the wheels 21 crosses the two wheels 23, the rotation between the axis 21 and the wheel 23 is facilitated by a sealed ball bearing 231. The pivot axis 22 is almost vertical when the tip is placed on the ground and the cane in the walking position. The rotation between the part secured to the cane 11 and that secured to the axis of the wheels 24 is done using a ball bearing 241 included in the block secured to the axis of the wheels. The pivot axis 22 makes an angle of approximately 45° (between 30 and 60 degrees) with the axis of the cane 25. As a non-limiting example, the diameter of the wheels can be 65mm (between 25mm and 100mm) and the spacing between the two wheels of the order of 50mm (between 25 and 75mm). The rubber seal 12 of the “Silent Bloc” type with a diameter equal to that of the rod (typically between 12mm and 14mm) and 8mm thick (between 4 and 20mm) for example makes it possible to absorb the shock when the rod meets a stop.The anti-rotation joints 13 and 14 allow the tip to be changed and prevent rotations around the axis of the rod between the tip and the last segment of the rod. The forward inclined plane 28 helps to pass the stops; it is typically of the order of 45 degrees and is between 30 and 60 degrees.

[0038] [Fig.3] represents the tip seen from below, we can see the distance between the axis of pivot 22 and the wheel axis 21 (also called caster offset) which can be, by way of non-limiting example, of the order of 25mm (between 10 and 45mm).

[0039] [Fig.4] represents the tip seen from above, the stop secured to the rod 26 comes meet the stop secured to the wheel axle 27 in order to limit the angle around the pivot axis to a value of the order of 50° for example.

[0040] [Fig.5a] represents a non-limiting example of embodiment of the blocking means of rotation around the axis of the rod 25. The male 15 and female 16 locking pieces are integral with their respective rod segments. [Fig.5b] represents another alternative locking device with the locking pieces 17 and 18 integral with their respective segments.

[0041] To enable the user to correctly position the wheels when he grasps the cane and places it on the ground, the sleeve may for example contain a flat on the right parallel to the plane of the wheels. Once the different segments have taken their position when unfolding the cane, having this flat on the right in the vertical plane allows the wheels to be correctly positioned.

Claims

1.

2. Claims White cane device for locomotion for visually impaired people, characterized in that it comprises • a tip consisting of at least two wheels of the same diameter of a few centimeters having a common axis of rotation called the wheel axis and spaced a few centimeters apart; • a second axis of rotation, of almost vertical direction, when the cane is held by the user, called the pivot axis, located a few centimeters in front (in the direction of movement of the person) of the axis of the wheels, and being halfway between the planes of the two wheels, the pivot axis allowing the end of the cane to rotate relative to the block consisting of the tip containing the wheels; • a means of locking the different segments constituting the rod so that they cannot rotate relative to each other along the axis of rotation constituted by the axis of the rod; • on the end of the rod and the base of the tip of the stops which will limit the amplitude of the rotation around the pivot axis between + 50° and -50°, 0° corresponding to the position where the axis of the rod is parallel to the plane of the wheels; • an addition at the end of the rod before the tip, consisting of a flexible rubber joint of the “silent bloc” type, with a diameter close to that of the rod, a few millimeters long in order to absorb shocks; • a cane knob or sleeve which contains a flat surface or other means of identification so that visually impaired people can immediately see, by holding the sleeve, how the wheels are positioned in space. White cane device according to any one of the preceding claims, characterized in that the wheels rotate freely relative to each other with respect to their axis of rotation. common.

3. A white cane device according to any one of the preceding claims, characterized in that rotation of the cane segments around the cane axis is prevented by male-female type locking pieces fixed to the ends of the segments in order to fit together eliminating the degree of freedom of rotation.

4. White cane device according to any one of the preceding claims, characterized in that the two wheels are identical and covered with an abrasion-resistant rubber of the polyurethane rubber type.

5. White cane device according to any one of the preceding claims, characterized in that the rotations of the wheels around their common axis are ensured by sealed ball bearings and that the rotation around the pivot axis is ensured by a sealed ball bearing.

6. White cane device according to any one of the preceding claims, characterized in that the quasi-vertical pivot axis is connected to the end of the cane by an elbow at approximately 45°.

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