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(11) | EP 0 016 606 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Aids for the blind and visually handicapped |
| (57) An aid for the blind and visually handicapped has a pistol grip at one end of straight
member 10 carrying spaced ground wheels 22 on downwardly inclined end element 18.
A linkage 7 is pivoted on element 18 and carries lateral resilient probes 34, 35 which
can be retracted to lie rearwards by sliding knob 45 to operate linkage 7. A user
holds the grip whilst walking and can sense changes in ground level and texture and
vertical obstacles which deflect the probes. On release the probes return to their
operative, lateral, position. |
[0002] It is known for a blind person when walking forwards to use an aid in the form of a so-called long stick, which is straight and in some cases can be collapsed for transport. The user, whilst walking forwards, holds the stick downwardly and forwardly, and swings the stick from side to side to sense vertical obstacles, and also taps on the ground to sense changes in ground level, e.g. a road kerb. It will be appreciated that unless forward progress is very slow, some vertical obstacles and changes in ground level will be missed and in general a user will restrict his forward speed to a level which enables most obstacles to be sensed. Prolonged use of the stick can produce fatigue in the user's arm .
[0003] According to this invention an aid for the blind and visually handicapped comprises an elongate member, ground engaging roller means for the elongate member, and probe means extending transversely of the elongate member for detecting obstacles.
[0005] The invention also includes a method of walking using such an aid with the elongate member extending forwards.
[0006] Preferably probe means are adapted to extend laterally of the elongate member, the probe means being deflectable and on release arranged to return to its lateral position.
[0007] With such an aid, a user can readily sense vertical obstacles and changes in ground level on a continuous basis whilst moving forwardly. The aid is most effective if there are two probes adapted to extend laterally respectively on both sides of the elongate member.
[0008] If the roller means comprises two laterally spaced rollers this is particularly useful in locating the elongate member at right angles to a step or kerb.
[0009] In one embodiment the probes are inherently resilient and comprise a plastics tube with an inner fibre glass rod.
[0010] Preferably, for ease of transport and convenience on buses and the like, the probe means is retractable to a position which extends generally towards the other end of the elongate member. Conveniently the probe means is retracted through a linkage connected to an operating element by a rod extending along the elongate member, and releasable detents are preferably provided to resist undesired retraction and extension of the probe means.
[0011] The invention may be performed in various ways and two specific embodiments with possible modifications will now be described by way of example with reference to the accompanying drawings, in which:-
Fig.1 is a perspective view of an aid for blind or other visually handicapped persons;
Fig.2 is an enlarged perspective view of part of the aid;
Fig.3 is a part section of part of the aid;
Fig.4 is a section on the line 4-4 of Fig.3;
Fig.5 is a side view, part in section, of an end of a probe; and
Fig.6.is a part side view of part of a modified arrangement.
[0012] The aid comprises a straight rigid lightweight elongate member 10 formed from square or other section aluminium or plastics extrusion. A cylindrical rod (not shown) is releasably received in the upper end of the member 10 and is secured in place by a bolt extending through the rod and the member 10 and held in place by the bolt and a wing nut 11 . Other forms of releasable fastener could be used to hold the rod. The rod extends beyond the member 10 and has removably secured to it by nuts and bolts 12 a directional hand grip in the form of a pistol grip 13 formed in two halves 13a, 13b each moulded of plastics, for example acrylonitrile butadienestyrene.
[0013] The two halves are secured together by nuts and bolts 14. The grip has a trigger-like rest 8 for the index finger and grooves 15 for the other fingers. A flexible plastics strip 16 has one end held in the hand grip and the other end is apertured to receive the bolt of bolt and wing nut 11. There may be a number of spaced apertures in the strip 16 so that its effective length can be adjusted. The strip forms loop 17 with the grip so that a user may place his arm through the loop 17 to carry the aid. It will be observed that the loop 17 is located so that when the aid is in use the hand or arm does not extend through the loop so that the user can readily release his hold on the grip if desired for example if the aid becomes trapped.
[0014] At the lower end the member 10 is riveted at 9 to bent or cranked element 18 of aluminium or plastics sheet having apertures 19 to reduce its weight and increase strength and rigidity. The lower end of the member 10 receives a plug (not shown) and a horizontal hollow rod 20 fixedly extends through the plug, the member 10 and side edges 21 of the element 18. Two laterally spaced rollers or wheels 22 are rotatably carried on the ends of rod 20. The wheels 22 are very light in weight and are made for example from foamed plastics, for example ethyl vinyl acetate. They have wide flat road-engaging surfaces 23; this enables a user to sense slight changes in ground texture and level and assists in directional stability and preventing the aid from wandering from a straightforwards direction of movement. A long single roller extending across the aid could be used in some cases instead of the two rollers but two rollers are preferred.
[0015] The element 18 has a slot 24, in line with the member 10, in which can slide a pin 25. The pin 25 is pivotally connected to the inner ends of left and right links 26, 27 of linkage 7 above the element 18 and whose outer ends are pivotally connected at 28, 29 to left and right square section links 30, 31 themselves pivoted- respectively at 32, 33 to the element 18. Nylon washers are interposed between the relatively moving parts at the pivots.
[0016] Connected to the ends of links 30, 31 are resilient elongate probes or sensors 34, 35 which operate in a manner somewhat similar to the whiskers of a cat. The inner ends of the sensors extend through the respective link and are releasably held by rubber bush 36. Each sensor comprises an outer tube 37 of nylon plastics and an inner rod 38 of fibre glass. The exterior surface of the tube is smooth, and is designed not to snag in clothing. The ·tube has an integral locating flange 39. A tip portion 40 of plastics is screwed at 41 into the end of the tube 37 and is provided with a tactile marker in the form of an annular groove 42; when the tip portion has worn down to the groove 42 a user will know it should be replaced. Although the bush 36 holds the sensor firm, tne bush can be removed by a user and the probe or sensor withdrawn and replaced, the bush being then attached to the end of the probe. The flange 39 engages the lint to indicate to a user when the probe is in place. The assistance of a sighted person is not required.
[0017] A stainless steel rod 43 extending along member 10 connects the pin 25 to a cylindrical portion 44 screwed into an operating element in the form of a knob 45. A spring 46 is engaged between the knob 45 and a stainless steel washer 46a and biasses the knob outwardly. A-slot 47 is provided in the underside of the member 10 with enlarged portions 48, 49 at its lower and upper ends. In the position shown in Figs.2 and 3 the knob is in portion 48 and the probes 34, 35 are retracted to be inclined towards the member 10. The length of the slot 47 and the fact that the pivots are supported from beneath enables the probes to be retracted through more than 90° to bring the tips of the probes close to the member 10 thus reducing any tendency for the retracted probes to catch in obstacles or against the legs of a user. The portion 44 has side flats 50 so that, on depression of the knob, the knob can be moved upwardly as shown chain-dotted into the portion 49 causing· the pin 25 to move upwardly along the slot 24 bringing the probes 34, 35 to the operative position shown in Fig.1 in which the probes extend laterally of the aid. The engagement of portion 45 in slot portions 48, 49 provides a releasable detent. The knob must be depressed before it can be moved out of slot end portions 48, 49. In the arrangement shown, the user is left handed so that right-hand probe 35 is made longer than probe 34, so that probe 35 extends to beyond the right side of the user. The distance between the tips of the probes in the extended position is at least equal to the width across the widest part of a user's body, usually the shoulder, and in use the tips extend slightly outwardly of the respective shoulders so as to sense obstacles across the full width of a user's body. Different users can have probes of differing lengths. If the user were right-handed then probes 34, 35 would be interchanged. As can be seen from Fig.1, in the operative condition the linkage 7 holds the probes in front of the axle rod 20 but not in front of the foremost surfaces of the wheels 22, so that in use it is the wheels which will first engage a vertical or upstanding surface in front of the user.
[0018] To use the aid a user holds the grip with his hand at his side and walks forward with the rollers 22 engaging the ground. The user can sense, through the wide ground- engaging surface of the rollers, changes in ground level, changes in ground texture, e.g. water, gravel, ice, gaps between paving stones, and grass; and vertical obstructions, and should a probe engage an obstacle it flexes rearwards as shown chain-dotted in Fig.2; this flexing can also be sensed by a user whose forward progress is thus facilitated and the danger of collision with obstacles reduced. The probes can flex or bend through well beyond 90° and have effectively 100% recovery, that is they return to the lateral, operative, condition when the flexing force is removed. The resilient nature of the probes biasses them to the unflexed position of Fig.1 . When a step or road kerb is reached, the rollers can be lowered whilst being kept in contact with the front face 51 of the step riser until the rollers engage the next tread 52. This is facilitated by the generally flat element 18 being downwardly inclined with respect to the member 10.
[0019] The arrangement has certain advantages when compared with a conventional straight long stick as used by the blind and other visually handicapped. This stick is moved to and fro from side to side, and is tapped on the ground in a sequence of positions. Thus changes in ground level or in the nature of the ground may be missed and not all vertical obstructions will be engaged with the stick unless forward progress is made very slow. With the described arrangement the rollers sense ground level and surface characteristics at all times and the probes and wheels sense vertical obstructions in the path of the user. The directional hand grip reduces any tendency to veer away from a directly forward path as can happen with a conventional stick which inclines to left or right due to muscle fatigue in a user's arm.
[0020] It will be seen from Fig.1 that the two wheels 22 enable the. aid to be located with the member 10 at right angles to the edge of the step or kerb, which is not easily achieved with a conventional stick. As a safety feature the member 10 is provided with alternating coatings 53, 54 of light- reflective pressure-sensitive material, for example saturn yellow fluorescent and super high intensity reflective as supplied by Minnesota Mining and Manufacturing Co. of London.
[0021] The aid is light in weight being generally made of aluminium and plastics and may weigh for example 800 grams or less. The aid is entirely corrosion resistant and rust proof so that the aid can readily be cleaned under a tap or hose by a user without the assistance of a sighted person.
[0022] In a modification the probes are not retractable but extend laterally; the linkage is omitted and the probes are releasably connected to the lower end of the elongate stem 10 above the wheels.
[0023] In some circumstances it may be possible for the aid to have a single, longer, probe extending to one side of the aid but two probes are preferred.
[0024] It will be appreciated that the described aid, unlike a . conventional straight stick, is such that a visually handicapped person does not require lengthy training and practice before being able satisfactorilly to use the aid.
[0025] In a modification shown in Fig.6, the index finger rest 8 is pivoted at 60 to the handle and is movable outwards to the chain-dotted position under the control of a relay 61 energised by battery 62 through lines 63, The battery is replaceable through removable end cap 64. The relay is connected, through line 66 in element 10 to sensor 65 carried on element 18. The sensor 65 is a sound transmitter/receiver and is energised from the battery and is arranged to emit an ultrasonic probe beam generally vertically and includes means responsive to sonic reflections from overhanging obstacles. The beam could be circular, or fan-shaped in a lateral plane. The sensor is arranged to pass a pulse to the relay when an obstacle is sensed of a height, for example, of up to 1.8 metres above the height of axle 20, but not above that height. When the relay is energised by the pulse it causes the rest 8 to move outwards providing a tactile indication of the presence of the obstacle. The relay is re-set manually. An on-off switch (not shown) is provided.
[0026] In a further modification means are provided for sensing the distance travelled. The wheel hubs 67 are cast and have six equi-angularly spaced radial vanes 68 on the inside. A suitable light source 69 carried on element 1.8 is responsive to light reflections from the vanes and includes counting means arranged, after successive predetermined rotations of the wheel, to send a pulse through line 69' in element 10 to micro electric motor 70 energised from the battery through a connection (not shown) and arranged to index one or more of three wheels 71 arranged on a common axis in the handle and partly projecting from the handle. Each wheel carries Braille symbols for 0 to 9 and can be sensed by the index finger to give a user an accurate indication of the distance travelled. This is particularly useful when, for example, crossing a road. An on-off switch (not shown) is provided.
1. An aid for the blind and visually handicapped comprising an elongate member characterised
in that ground engaging roller means (22) are provided for the elongate member, and
probe means adapted to extend transversely of the elongate member for detecting obstacles.
2. An aid as claimed in Claim 1, in which the roller means (22) and probe means (34,
35) are at one end region of the elongate member.
3. An aid as claimed in Claim or Claim 2, in which the probe means (34, 35) is adapted
to extend laterally of the elongate member (10) the probe means being deflectable
and on release arranged to return to its lateral position.
4. An aid as claimed in Claim 3, in which the probe means comprises two elongate deflectable
probes adapted to extend respectively laterally to the two sides of the elongate member
and arranged when released to return to their lateral positions.
5. An aid as claimed in Claim 3 or Claim 4, in which the probe means has a replaceable
tip portion (40) :
6. An aid as claimed in Claim 5, in which the tip portion (40) includes a tactile
marker (42).
7. An aid as claimed in any of Claims 3 to 6, in which the probe means has inherent
resilience.
8. An aid as claimed in Claim 7, in which the probe means comprises an outer plastics
tube (37) surrounding a fibre glass rod (38) extending along the tube.
9. An aid as claimed in any preceding Claim, including means (7, 43, 45) for moving
the probe means between an operative position in which it extends transversely of
the elongate member and an inoperative position in which it extends generally rearwards.
10. An aid as claimed in Claim 9, in which said means for moving comprises a linkage
mechanism (7) connecting the probe means to an operating element (45) movable between
probe-operative and probe-inoperative positions.
11. An aid as claimed in Claim 10, in which the linkage mechanism is connected to
the operating element (45) by a rod (43) extending along the elongate member (10).
12. An aid as claimed in Claim 10 or Claim 11, including releasable detent means (48,
49) for holding the operating element (45) in said positions.
13. An aid as claimed in any preceding Claim, comprising a part (18) adjacent the roller
means downwardly inclined with respect to the elongate member to facilitate descent
of a step by a user.
14. An aid as claimed in any preceding Claim, in which the roller means comprises
two laterally spaced rollers (22).
15. An aid as claimed in any preceding Claim, including a directional hand grip (13)
for the elongate member (10).
16. An aid as claimed in any preceding Claim, in which the probe means comprises ultrasonic
means (65) adapted to operate a tactile indicator (8).
17. An aid as claimed in any preceding Claim, including means (69) responsive to rotation
of the roller means arranged to operate a tactile part (71) for providing a tactile
indication of distance travelled.
18. A method of walking comprising using an aid as claimed in any preceding claim with
the elongate member extending forewards.