WO2007110638A1

WO2007110638A1 - Apparatus to aid the traversal of a staircase

Info

Publication number: WO2007110638A1
Application number: PCT/GB2007/001123
Authority: WO
Inventors: Alan R. Turner-Smith; John Harding; Louis Blache
Original assignee: King's College London
Priority date: 2006-03-29
Filing date: 2007-03-28
Publication date: 2007-10-04
Also published as: GB2459791B; GB0913516D0; GB2459791A; GB2436555A; GB2436555B; GB0606275D0

Abstract

An apparatus to aid the ascent or descent of a staircase (10) by a user (1), comprising: a guide means (20) provided generally parallel to the inclination of the staircase; a carriage (40) slidably engaged with said guide means,- and a handle (30) carried by said carriage, said apparatus being characterised by further comprising a control mechanism comprises means for permitting incremental movement along said guide means, the means being further arranged such that initiation of an increment of movement is caused by a user exerting an activation force on said handle (30) whereby to move said handle in a predetermined activation direction. Such a apparatus with an ascent handle (34) and a descent handle (32) which are located, for the same position of the carriage (40), at different positions.

Description

APPARATUS TO AID THE TRAVERSAL OF A STAIRCASE

Technical Field

The present invention relates to an apparatus to assist the ascent and descent of a staircase, and which is in particular provided with ascent and descent handles provided, for the same position on the staircase, at different positions depending on whether an ascent or descent is being performed. From another aspect, the present invention also relates to an apparatus particularly to aid the traversal of staircases, which by virtue of a rocking operation of a handle allows the incremental traversal of a staircase.

Background to the Invention and Prior Art

With the onset of older age limitations on activity imposed by ill health and disability are common. Of these, mobility problems are very common, affecting a large proportion of older people. With such mobility problems a difficulty or inability to ascend or descent stairs can result, which can have a great impact on the degree of independence an older person may enjoy, and in particular in their own home. While it is well known in the art that powered stair lift systems are readily available, such powered stair lift systems are commonly expensive, and can be detrimental in terms of depriving an older person of valuable exercise involved in ascending and descending stairs. It is therefore advantageous, if possible, to provide an arrangement which permits an older person, or other disabled or partially disabled person, to ascend and descend stairs on their own, but with any aid necessary for example to prevent falls, or other accidents.

Arrangements are known within the prior art which address this problem. One example prior art document which describes such an arrangement is GB 2309468, which describes a device to assist the ascent and descent of a staircase. An example taken from this prior art document illustrating the device, and the ascent and descent of a staircase using the device is shown in Figures 1 and 2.

With reference to Figure 1, the prior art device comprises a staircase banister system having two banister rails 12, disposed on either side of a flight of stairs, together with a rod 18 disposed substantially horizontally across the staircase and adapted to engage both banister rails. Each banister rail incorporates a groove 14, having slots 16 disposed along its length, for example at each step position. In use a person wishing to climb the staircase stands at the foot of the stairs, and engages the rod in the groove 14 sliding the rod up the groove 14 until it engages in a slot 16. The rod 18 thus being held between the two banister rails can be used to assist the climbing of the first one or two stairs. The rod is then retrieved from the slot 16, slid further along the groove 14 up to the next slot 16, in which it is then secured, and the person then ascends the next one or two stairs. This action is repeated until the user 1 has ascended the stairs.

Figure 2 illustrates the user 1 descending a staircase, using the same system. Here, the operation is in reverse, with the rod 18 being inserted into the groove 14 in the banister rail at the top of the stairs, and slid down the groove until it locks into a slot 16. The user 1 then descends one or two stairs, repeating the operation until all of the stairs have been descended.

With such an arrangement, therefore, the rod 18 when located in the slots 16 provides a substantially fixed rod which supports the user 1 in ascending and descending stairs.

A device similar to that described in GB 2309468 which has been commercially available previously is the "Stair Bar" available from Nuvations, of 11 Hale End, Hook Heath, Woking, Surrey, United Kingdom. An example "Stair Bar" product is shown in Figure 3 which illustrates in more detail the banisters 12 provided with grooves 14 and slots 16. In particular, it can be seen how the rod 18 is introduced into the groove 14, and can then be secured within a slot 16, to provide support.

Although products such as those described in GB 2309468 or the "Stair Bar" product are robust and have very few moving parts thus requiring little maintenance, problems arise during their use in that typically, such an arrangement provided with only a single groove 14 may be advantageous for either ascending or descending a staircase, dependent on the height of the banister 12 bearing the groove 14 above the level of the stairs. However, such an arrangement does not allow for particularly comfortable ascent and descent of the staircase, for following reason. More particularly, typically a user of such a device will find the use of the device most comfortable and convenient when the device at a position one or two steps in front of the user's present position is at such a height that the user's hands are substantially at chest height. Such a position allows a user to use their upper body strength to help climb the stairs, if necessary. However, as shown in Figures 1 and 2, a positioning of the banister 12 which provides such a height for the rod 18 one or two steps ahead on an ascent of the staircase does not provide a convenient positioning of the rod on a descent. More particularly, as shown in Figure 2, when the rod is placed one or two steps ahead of the user's present position on a descent, the location of the rod becomes much too low for the user to comfortably and conveniently use. Moreover, with such a low position for the rod on a descent of the staircase, the safety of the device is decreased, and the risk of damaging falls correspondingly increases.

One possible solution to this problem is to provide two sets of banisters 12 at different heights, with one set being used for a staircase ascent, and another set used for a staircase descent. Such arrangement is in fact shown in Figure 3, where it can be seen that two grooves 14 are provided in the banister. However, such a solution increases the unsightliness of the banister, and a user must remember in which of the grooves 14 the rod is to be inserted, for an ascent or descent. In particular, once an ascent or descent has been commenced it is not possible usually to change the rod 18 from an ascent groove to a descent groove or vice versa, and hence groove selection on the commencement of an ascent or descent is important. In particular on a descent, if the incorrect groove is chosen and the descent then commenced, then the safety of the user is put at risk. Additionally, typically the difference in height created by the use of two separate grooves is insufficient to fully alleviate the problem.

An additional drawback is that typically with such "Stair Bar" arrangements, the user must grip the bar quite tightly and manipulate the bar with a high degree of dexterity in order to move the bar along the groove 14, and to retrieve the bar 18 from its locking positions in the slots 16. For frail users with manual dexterity problems, such an operation can prove too complicated, meaning that the Stair Bar cannot be reliably used with such users.

Summary of the Invention To address at least some of the above noted problems, embodiments of the present invention provides an apparatus which provides different ascent and descent aids, preferably in the form of ascent and descent guard rails or bars provided at different positions for the same stair position, dependent on whether an ascent or descent is being performed. In embodiments of the invention the ascent and descent bars are mounted on the same fitting attached to a single rail, such that the ascent and descent bars move together up and down the stairs in unison. The provision of separately positioned ascent and descent aids means that the height of the aids can be set to the correct height for the user for both the separate ascent and descent, and moreover the movement of the bars together provides an additional advantage that the user is further guarded against falling forwards or backwards during an ascent or descent, by the additional bar.

Moreover, in order to address the further problem which may present itself to users with low manual dexterity, from another aspect embodiments of the invention provide an arrangement for the traversal of a staircase, wherein a guard aid such as a rail or bar is provided to support a user, which is incrementally moved up or down a staircase along a guide rail by the provision of stopping points along the guide rail, which stop the movement of the aid. hi order to overcome the stopping points, the guard aid is mounted on a carriage mechanism which operates to overcome the stops by virtue of the rail or bar being gently rocked by the user. The rocking motion causes the carriage to overcome the stops, such that it can then proceed along the rail towards the next stop. Such a rocking motion can usually be produced by a user even with low manual dexterity skills, and does not require detailed manipulation of the descent bar.

As noted above, the inventors have found that a "rocking motion" of a supporting handle to initiate the next phase of an incremental movement has proved to be particularly intuitive and easy to operate for many users, and particularly those of low manual dexterity. Whilst in the embodiments mentioned below such a movement is used to initiate an incremental descent phase its use is not limited to such, and it can also be used to initiate ascent movements. Therefore, from a first aspect the present invention provides an apparatus to aid the traversal of a staircase by a user, comprising: a guide means provided generally parallel to the inclination of the staircase; a carriage slidably engaged with said guide means; and a handle carried by said carriage, said apparatus being characterised, by further comprising a control mechanism comprises means for permitting incremental movement along said guide means, the means being further arranged such that initiation of an increment of movement is caused by a user exerting an activation force on said handle whereby to move said handle in a predetermined activation direction.

Moreover, from a second aspect the present invention comprises an apparatus to aid the ascent or descent of a staircase by a user, comprising: a guide means provided generally parallel to the inclination of the staircase; and a carriage slidably engaged with said guide means; said apparatus being characterised by further comprising a handle providing, for an ascent of the staircase, an ascent handle, and, for a descent of the staircase, a descent handle, the ascent handle and descent handle being located, for the same position of the carriage, at different positions. With such an arrangement the problems noted earlier of different positions of a supporting handle being required for an ascent or descent of the staircase can be addressed.

In a preferred embodiment said handle comprises said ascent handle and said descent handle separately provided, so as to be mutually carried by said carriage. More preferably the ascent handle is provided on said carriage extending into a position so as to be accessible to the front of a user during an ascent of the staircase, and moreover the descent handle is also provided on said carriage extending into a position so as to be accessible to the front of a user during a descent of the staircase. Thus, whether descent or ascent is being performed a supporting handle can be provided at the correct position, and moreover the other handle (ascent or descent, depending on direction of movement) then extends behind the user. Thus the user is left with an increased feeling of security by virtue of having supporting handles extending both in front of and behind her body.

To enhance this feeling of security, in more preferred embodiments said ascent and descent handles are mounted on said carriage so as to extend in substantially opposite directions, whereby to define a user space between said handles in which to accommodate a user when in use. Thus, the user is provided with a defined operating space in which she can be securely accommodated whilst using the apparatus.

Preferably the ascent and/or descent handles are rotatably connected to said carriage, whereby to allow said handles to be rotatably moved with respect to said carriage about at least one axis of rotation, or more preferably about two or three axes of rotation. Preferably these axes are substantially orthogonal. The provision of this rotatable movement of the handles allows the handles to be folded out of the horizontal plane of the staircase when not in use, or additionally or alternatively to allow the handles to be moved to allow easy entry and exit into the user space defined by the handles. Moreover, the additional axes of rotation allow further movement of the handles, even when in the folded position, for example to move the handles out of the way of doorways, which may commonly be located next to the tops of staircases.

hi preferred embodiments said carrier comprises an ascent control mechanism and a descent control mechanism. More particularly, preferably said guide means is provided along its length with a series of engagement holes, and said ascent control mechanism comprises an ascent pawl arranged to ratchet along said series of engagement holes during an ascent. Conversely, preferably said descent mechanism comprises means for permitting incremental descent along said guide means, the means being further arranged such that initiation of an increment of descent is caused by a user exerting an activation force on said descent handle whereby to move said descent handle in a predetermined activation direction. The provision of the ascent and descent mechanisms allows for the different requirements on ascent and descent to be taken into account. For example, on ascent a user may tire and require the ascent to be stopped at any point to rest. The use of the ratchet mechanism allows an ascent to be halted at any intermediate point on the staircase, and the carriage will be held at that point, hi contrast, on the descent it is less likely that a user will tire, but there are increased concerns of the handle getting too far in front of a user. Using an incremental descent mechanism can alleviate such concerns.

Preferably said descent handle extends from a pivotable connection to said carriage, whereby the activation force causes said ascent handle to rotate about said pivot, said rotation initiating an increment of descent. Thus the user can engage in a "rocking motion" of said handle to initiate the next incremental descent phase, and then push the handle through the next incremental phase. The inventors have found such a rocking motion to be intuitive, and easy for users to operate, particularly those with low manual dexterity. Moreover, in preferred embodiments a counterweight is slidably attached to said guide means, and arranged to counterbalance the carriage and handle. This allows for a user to not have to exert much force to move the carriage and handle arrangement. Preferably only the frictional force between the guide means and the carriage need be overcome.

Preferred embodiments preferably also further comprise a fail-safe mechanism to lock movement of said carriage along said guide means in the event that said counterweight fails to counterbalance said carriage and handle. This is an additional safety feature which enhances the safety of the apparatus.

Further aspects, features, and advantages of the present invention will be apparent from the appended claims.

Description of the Drawings

Further features and advantages of the present invention will become apparent from the following description of embodiments thereof, presented by way of example only, and by reference to the accompanying drawings, wherein like reference numerals refer to like parts, and wherein: -

Figure 1 is a drawing illustrating a prior art arrangement;

Figure 2 is a drawing illustrating a prior art arrangement;

Figure 3 is a collection of photographs of a prior art arrangement;

Figure 4 is a computer generated drawing illustrating an embodiment of the present invention;

Figure 5 is a computer generated illustration of an alternative embodiment of the invention;

Figure 6 is a computer generated drawing of a part of an embodiment of the present invention; Figure 7 is a computer generated illustration showing an embodiment of the present invention in use;

Figure 8 is an image of an alternative embodiment of the present invention;

Figure 9 is a drawing illustrating an embodiment of the present invention;

Figure 10 is a plan view of an embodiment of the present invention;

Figure 11 is a side sectional view of a part of an embodiment of the present invention;

Figure 12 is a front view of a part of an embodiment of the present invention;

Figure 13 is a plan sectional view of the part of the present invention shown in Figure 12;

Figure 14 is a side sectional elevation view of the part of the present invention shown in Figures 12 and 13;

Figure 15 is a front elevational view of the part of the embodiment of the present invention shown in Figures 12 to 14;

Figure 16 is a further front elevational view of the part of the embodiment of the present invention of Figures 12 to 15;

Figure 17 is a further side elevational view of the part of the present invention shown in Figures 12 and 16, but with an alternative latch arrangement;

Figure 18 is a further front elevational view of a part of an embodiment of the present invention shown in Figures 12 and 17;

Figure 19 is a plan view of the part of embodiments of the present invention shown in Figures 12 to 18; Figure 20 is a sectional diagrammatic view taken along the line AA of Figure 21;

Figure 21 is a sectional diagrammatic view taken along the line DD of Figure 22;

Figure 22 is an end on view of a carriage assembly used in embodiments of the present invention;

Figure 23 is a sectional diagrammatic view taken along a line BB of Figure 21;

Figure 24 is a sectional diagrammatic view taken along a line CC of Figure 21;

Figure 25 is a front diagrammatic view of a carriage assembly used in embodiments of the present invention; and

Figure 26 is a diagram of a stop member used in embodiments of the present invention.

Description of the Preferred Embodiments

Embodiments of the present invention will now be described with respect to Figures 4 to 26.

An overview of elements of a preferred first embodiment of the present invention will first be given with respect to Figures 4, 9 and 10. Here, with reference to Figure 4, embodiments of the present invention provide a staircase ascent and descent assistance apparatus to help the ascent or descent of a staircase by a user 1. The apparatus comprises a rail 20, and slidedly mounted on the rail 20 is a handle member 30, comprising in this embodiment an individual ascent handle, and descent handle. The rail 20 may be mounted on an adjacent wall to the staircase 10, or alternatively may be provided with legs 22, attached to a telescopic mount 24, which extends across the staircase, as shown in Figure 6. Provision of the legs 22 with the telescopic mount 24 means that the rail 20 does not need to be permanently fixed to the wall adjacent the staircase 10, allowing for the entire arrangement to be portable, and transferable from location to location. Figures 9 and 10 illustrate the assistance apparatus in greater detail. With reference to Figure 9, the apparatus according to the present embodiment comprises the rail 20, slidebly mounted upon which is a carriage 40. Rotatably affixed to the carriage 40 is a handle member 30, comprising an ascent handle member 34 to be gripped by the user 1 while ascending the staircase 10, and a descent handle member 32, to be gripped by the user 1 while descending the staircase 10. Provided at intervals along the rail 20 are stop members 28, preferably equally positioned along the length of the rail 20, every one, two, or more steps. The rail 20 is provided along its length with rail stop location holes 204, as shown in Figure 25, which allow the stops to fitted at substantially any point along the rail as necessary for any particular installation. Thus, the stops can be positioned along the rails in line with the individual stairs. Moreover, although as mentioned the stops are preferably equally positioned along the rail, the stops can, if necessary, be unequally positioned, such that the spaces between stops differ. This facility allows for maximum flexibility in installing the apparatus on any particular staircase, and for taking into account user preferences.

As shown, the rail 20 is supported by legs 22 at intervals along its length, which themselves rest upon the staircase 10 via a telescopic cantilever support member 24, which extends across the stairs, as shown and described previously with respect to Figure 26. As mentioned, the use of the legs 22 and the cantilever support members 24 means that the entire arrangement is essentially self supporting and the rail 20 does not need to be permanently affixed to any adjacent wall to the staircase 10. Additionally, as shown in Figure 9 the rail 20 does not extend beyond the top or bottom of the staircase 10, and thus is particularly advantageous if, for example, there is a doorway located at the top or bottom of the staircase, as the rail does not obstruct the doorway. It is possible for the rail not to have to extend beyond the staircase 10 because of the mounting of the handle 30 on the carriage 40 such that the ascent handle member and descent handle member extend outwards to either side. Such extension allows the handles to provide support in front of the user beyond the staircase for the last few steps of an ascent or descent, but without requiring the carriage, and hence the rail, to extend beyond the staircase.

As noted above, the carriage 40 is slidably mounted on the rail 20, such that it may slide up and down the rail, upon being pushed by the user in the appropriate direction. In order to provide for easy operation, and particularly on ascent such that the user does not have to push the entire weight of the carriage and handle member, a counter balance 26 is further provided slidably mounted on the underside of the rail 20, and attached to the carriage 40 via a wire extending up along the rail 20, and over a pulley or other arrangement at the top end of the rail 20, to attach to the carriage 40 at the upper side thereof. Thus, the carriage 40 and counter balance 26 move in opposite directions to each other along the rail, the counter balance being weighted to match the weight of the carriage 40 and handle member 30 as closely as possible. Matching the weight of the counter balance 26 and the carriage 40 and handle member 30 means that on ascent of the stairs the user 1 need only overcome the friction forces of the carriage 40 and rail 20 to push the carriage 40 bearing the handle member 30 up the stairs, and likewise on a descent the same operation is achieved. The use of the counter balance 26 is particularly important for a descent, such that the carriage 40 and handle member 30 do not run away down the rail 20.

Please note that Figure 9 illustrates a carriage member 40 bearing a handle member 30 at both the top position next to the user 1, and at a bottom position. This is for illustration purposes only, and typically, on any one rail only a single carriage member 40 bearing a handle member 30 would be provided.

Figure 10 illustrates the apparatus according to the presently described embodiment from a plan view, giving an idea of the shape of the ascent handle member 34 and descent handle member 32 forming the handle member 30, in that they are both curved. . Additionally, Figure 10 illustrates that the handle member 30 is hingedly mounted in a first direction onto the carriage 40, such that the handle member 30 may rotate about an axis extending perpendicular to the plane of the handle member 30 as shown in Figures 9 and 10 to permit entry and exit into the handle member by a user. Moreover, provided on the handle member 30 are guide rods 304 and 302 which extend in the plane of the handle member in the direction of the rail 20. These guide rods contact the rail 20 when the carriage 40 bearing the handle member 30 is in a position in the middle of the rail 20, but when the carriage 40 is at a position at either end of the rail 20, one of the guide rods 304 or 302 no longer contacts the rail, thus allowing the handle member to rotate about hinge 468 in one or other direction. More particularly, as shown in Figure 10 when the carriage 40 is at the top of the rail 20 (in the left hand position of Figure 10) the guide rod 304 is no longer in contact with the rail 20, such that the handle member 20 may pivot about the hinge 468 to an entry and exit position as shown by the dotted lines. Similarly, when the carriage 40 bearing the handle member 30 is at the bottom of the rail 20 (as shown in the right hand position of Figure 10) then the guide rod 302 no longer contacts the rail 20 allowing the handle member 30 to rotate about the hinge 468 in the opposite direction, again to permit entry and exit into and out of the handle member.

Figure 10 also illustrates the shape of the ascent and descent handle members 32 and 34 forming the handle member 30 in this preferred embodiment, in that they are preferably curved. However, it should be noted that this shape is not essential to the invention, and the handle members may take different shapes, and in particular may be straight, or take more complicated forms. Figure 5, for example, illustrates an alternative form of the handle member which may be used in other embodiments of the invention. However, it is important that ascent and descent handle members which provide for a handle to be held by the user at a convenient and comfortable height for both ascents and descents of the staircase 10, are provided.

Moreover, Figure 9 illustrates that the handle member 30 comprising the ascent and descent handle members 34 and 32 is arranged in a substantially horizontal plane. However, this is not an essential feature of embodiments of the invention, and the handle member 30 may be arranged at an inclined angle, and moreover the ascent and descent handle members 32 and 34 may be at offset heights to each other. This is important because the purpose of providing the ascent and descent handle members is, as mentioned, to allow for a handle member to be provided at a correct height during both the ascent and descent of the staircase 10. Thus, individual adjustment of both the relative heights of the ascent and descent handle members with respect to each other, as well as their inclination should preferably be performed, for any particular user 1. Generally, however, the inventors have found that orientation of the handle member with the ascent and descent handle members at the same relative height, and with the handle member inclined at horizontal gives a good level of performance for many potential users. Before describing the details of the carriage mechanism 40 and the rail 20 of the preferred embodiment, having given an overall outline of the structure of the assistance apparatus of the present embodiment, it will now be useful to give an overview of the operation of the apparatus of the present embodiment in use. Figure 7 is a sequence of diagrams illustrating such operation.

More particularly, Figure 7.1 illustrates the apparatus where the carriage bearing the handle member 30 is positioned at the top of the stairs, and the handle 30 has been rotated upwards and to the side, in order to allow entry of the user 1 into the inner circumference of the handle member 30. In this respect, the handle member 30 is hingedly connected to the carriage member 40 by both the hinge 468 noted previously, and also an additional hinge to allow rotation of the handle member upwards about a horizontal axis. As shown in Figure 7.1 the user 1 steps inside the circumference of the handle member 30, and then as shown in Figure 7.2 rotates the handle member 30 such that the user becomes essentially substantially surrounded by the handle member 30, when the member is in its operating position. With reference to Figure 9, the user then pushes the handle member 30 down the rail 20, overcoming any factional forces between the carriage 40 and the rail 20. Because of the counter balance 26, the carriage 40 bearing the handle member 30 does not "run away" from the user down the rail.

The carriage member 40 bearing the handle member 30 proceeds down the rail 20 under the force of the user's push until the carriage member 40 meets a first stop member 28 positioned along the rail 20, perhaps every one, two, or more steps. The carriage member 40 then stops. The user 1 then steps down the stairs holding onto the descent handle member 32. In order to cause the carriage member 40 to overcome the stop 28, the carriage member 40 is provided with a mechanism to be described in detail later, which permits the user 1 to apply a rocking motion to the descent handle member 32, which causes the carriage member 40 to overcome the stop 28 such that it may then be pushed further down the rail 20 in the direction of the next stop. Such a rocking motion is easy for older people with low manual dexterity to perform, and the mechanism which allows the rocking motion to overcome the stop therefore provides for a controlled incremental descent of the carriage member 40 bearing the handle member 30 and the user 1 down the staircase 10. At each stop member 28 the rocking motion is repeated by the user 1 to allow the carriage member 40 to overcome the stop. The operation is repeated at each stop until the bottom of the stairs is obtained. At the bottom of the stairs, the handle member 30 may be rotated as shown in Figure 10, to permit exit of the user 1 from inside^" the circumference of the handle member.

On an ascent, essentially the same operations are performed although in this embodiment no rocking motion is required. As shown in Figures 7.3 and 7.4 the user manipulates the handle member 30 via its hinged connection to the carriage 40, in order to enter the circumference of the handle member. The user 1 then pushes the ascent handle member 34, in order to push the handle member 30 borne by the carriage 40 up the rail 20. The counter balance 26 counters the weight of the carriage 40 and handle member 30, such that the user should overcome no more than the frictional forces between the carriage 40 and rail 20 in order to push the carriage 40 up the rail. A ratchet mechanism is used in the carriage 40, in order to ratchet the carriage 40 up the rail. Use of such a ratchet mechanism stops the carriage 40 from sliding backwards, when the user no longer pushes against the ascent handle member 34. On the ascent the ratchet mechanism is such that the stops 28 play no part, and instead the ratchet mechanism is used to hold the carriage 40 in place when the user stops pushing the ascent handle member 34. Thus, the user can rest when climbing the stairs, at any point. Typically, the user would push on the ascent handle member using the handle member for support, as the user climbs the stairs.

With such an apparatus as described above in respect of the preferred embodiment, several benefits are obtained. For example, the apparatus enables normal movement of the person, involving use of the leg rather than the arm muscles in walking. On ascent of the staircase the apparatus enables a person to lean on and walk up the stairs, rather than pulling themselves up. Such motion reduces the risk of falling backwards if the grip is lost. Additionally, a similar posture is also enabled on descent, and the rocking motion to provide for incremental descent is intuitive to most users. The provision of the handle member comprising both the ascent handle member and the descent handle member also engenders a particular feeling of security in users, as they are essentially surrounded by the handle members, and hence guarded from falling both forwards and backwards. Secret trials of the device have provided results that indicated that users felt particularly safe when using the apparatus. Having described the basic layout and operation of an embodiment of the invention, further details of the ascent and descent mechanisms included in the carriage 40, as well as the hinging mechanism which connects the handle 30 to carriage 40, will be described. Please note that the following details relate to a preferred embodiment representing the best mode of the invention presently known to the inventors. In other embodiments different mechanisms may be used, to provide the same, or at least a subset of, the functionality provided by the embodiment to be presently described.

Details of the connection of the handle 30 to the carriage 40 will first be described, with reference to Figures 11 to 19. Principally, the connection is a hinge connection hinged about at least two axes, and preferably three axes, to allow rotation of the handle both within the horizontal plane of the staircase as described previously with respect to Figure

10, but also to allow the handle to be lifted such that the ascent and descent handles extend vertically, and are no longer within the horizontal plane of the staircase. Such a feature is advantageous as it allows the handle 30 to be moved out of the way of the staircase so that the staircase can, for example, be used by able bodied users.

Additionally, the connection of the handle to the carriage also preferably permits rotation of the handle about a third axis orthogonal to the other axes, such that, when in the folded upright position the handle may be rotated from side to side, such that, for example, it may be moved out of the way of any doorway located at the top or bottom of a staircase.

Figure 11 illustrates a cross sectional view of the carriage 40 located within the guide rail 20. The guide rail 20 is provided with a stop member 28, as shown. The carriage 40 is provided with a central axle 410 onto which is rotatably attached a face plate 420, via bearing 414. Cover plates 430 and 440 are provided on top of the face plate 420, and all of plates 420, 430 and 440 are secured onto the axle 410 via bolt 412. Cover plate 440 has attached to its outer surface thereof a horse shoe shaped member 450 which is upstanding from the outer surface of plate 440, and is provided with a generally U-shaped surface, but having an inner circumferential surface 452 shaped so as to receive therein rectangular lift hinge supports 460, at certain positions. Figure 12 is a front view of the arrangement of Figure 11, illustrating the horse shoe shaped member 450 and its inner circumferential surface 452. Lift hinge supports 460 are also shown located within horse shoe member 450. The inner circumferential surface 452 of horse shoe member 450 is shaped such that lift hinge supports 460 may be rotated about central axle 410 but may only take certain positions. Figure 15 illustrates the positions which may be taken by the lift hinge supports 460 within the horse shoe member 450, with the different positions shown in dotted outline. In particular, it can be seen from Figure 15 that the inner circumferential surface 452 of horse shoe member 450 permits the lift hinge supports 460 to take one of four different positions, to allow the lift hinge supports 460 to rotate about axle 410, thereby allowing the handle 30 to be rotated from side to side. In this respect, Figure 15 illustrates a central position for the lift hinge support members 460, as also shown in Figure 12, with the auxiliary rotated positions being shown in dotted outline. The provision of the alternative positions provided by the horseshoe shaped member 450 enables the handle 30 to be set at an appropriate angle in relation to a given stair gradient.

Figure 12 also illustrates in dotted outline the shape of face plate 420. In particular it will be seen that face plate 420 which is rotatably mounted on axle 410 is provided at one end thereof with a slot 422, and at the other end thereof with protrusion 424 extending, with respect to Figure 12, into the plane of the page. Slot 422 and protrusion 424 form part of the descent control mechanism, to be described later. Face plate 420 is arranged on axle 410 with respect to outer plates 430, 440 and horse shoe shape member 450, such that if a user was to apply a turning force about axle 410 to the handle 30, then face plate 420 would move with the handle.

Figure 13 illustrates a cross sectional view taken looking along the length of the handle, and including two additional hinges 462 and 468, to permit further manipulation of the handle 30.

More particularly, Figure 13 illustrates the handle 30 being carried by handle carrying part 470 which is hingedly connected to second hinged part 464 via fingers 472 provided on handle carrying part 470, and fingers 474 provided on second hinged part 464. Fingers 474 and 472 are interdigitated, and are provided with a bore running the length therethrough (not shown) into which a pin is inserted to form hinge 468. Handle carrying part 470 carrying handle 30 can therefore rotate about hinge 468.

Second hinged part 464 is carried on lift hinge supports 460 and provides a hinge 462 comprising a pin provided in a bore within the body of second hinged part 464. Second hinged part 464 is provided at the other end from hinge 462 with a catch 466 which engages with lift hinge catch 4762, provided at the lower end of lift hinge supports 460. Lift hinge catch 4762 is activated by a handle bar lift release 476, as shown in Figure 14. Second hinged part 464 carrying handle carrier 470 and the handle 30 can therefore rotate about hinge 462, when lift hinge catch 4762 is activated to release catch 466. When the handle bar lift release 476 is activated, therefore, second hinged part 464 carrying the handle carrier 470 and the handle 30 may then be rotated about hinge 462 such that the handle 30 is lifted out of the horizontal plane of the staircase, as shown in Figure 14. It will be appreciated that the axis of rotation about hinge 462 is substantially orthogonal to the axis of rotation about hinge 468, which themselves are substantially orthogonal to the axis of rotation about axle 410. The degrees of motion provided by the arrangement of the hinges 462 and 468 therefore provide for the handle to be lifted out of the plane of the staircase, as mentioned, and to be rotated from side to side in the plane of the handle, for example to allow the handle to move out of the way of a doorway, or the like, which may be located at the bottom or top of each stair. Additionally, rotation of handle carrier 470 about hinge 460 also permits for easy entry and egress into or from the handle 30, as described previously with respect to Figure 10.

Figures 16 to 19 illustrate the hinged connection of the handle 30 to the carriage 40 in different positions. More particularly, Figure 16 is a front view illustrating the handle in the down position. Figure 17 is a side view of the handle in the same position, illustrating how second hinged part 464 carried on hinge 462 locks onto lift hinge catch 4762 so as to lock into position. In this respect, however, Figure 17 illustrates an alternative version of lift hinge catch 4763 when compared to Figure 14, in that the orientation of the catch has been reversed, as will be apparent from a consideration of the Figure. However, the operation of the catch shown in Figure 17 is substantially the same as that shown in Figure 14, and it retains the same functionality. Figure 18 illustrates the handle folded up i.e. second hinged part 464 rotated upwards about hinge 462, and also swung to one side about hinge 468.

Figure 19 illustrates how rail guides 302 and 304 are provided on the handle and rest against the outer surface of rail guide 20, such that in an intermediate position along the rail handle 30 cannot be rotated about hinge 468 when in the down position. Such operation was previously described with respect to Figure 10. Further details of the ascent and descent control mechanisms provided in the carriage 40 will now be described, with reference to Figures 20 to 26.

Carriage 40 comprises a front plate 402 (shown in Figure 25) and a back plate 404 (shown in Figure 21) within which is contained an ascent control mechanism, and a descent control mechanism. Front and back plates 402 and 404 are joined by rollers 4002, 4004, 4006 and 4008, respectively mounted on axles which join the front and back plates 402 and 404, and are rotatably mounted therein. Carriage 40 is contained within guide rail 20, as shown most clearly in cross section Figure 22 which illustrates the upward facing end of carriage 40. More particularly, it will be seen that guide rail 20 comprises a back plate 206, upper and lower sides 214 and 212, upper front side 208, and lower front side 210. Thus, guide rail 20 provides a partially enclosed volume within which carriage 40 is retained, in slidable engagement with the rail within the volume. Stop members 28 are provided at positions along the rail, as shown and described previously with respect to Figure 9. Each stop member 28 has the shape shown in Figure 26, and provides a first stop surface 282 which engages with a pawl forming part of the descent control mechanism, and an angled, arrow shaped lower surface 284 which engages in use with a down pawl latch 4090, as will be described later. Figure 21 illustrates the orientation of the stop members mounted on the rail 20 with respect to the carriage 40.

Additionally, as shown in Figure 22, upper end plate of carriage 40 has a hole therein, through ^"which counter weight connecting wire 4112 extends. Counter weight connecting wire 4112 proceeds up the guide rail to the upper end thereof, and is then looped round to attach to counter weight 26, as described previously.

With reference to Figures 20 and 21, the ascent control mechanism controlled within carriage 40 comprises ascent pawl 4020, shown in dotted outline in Figure 20. Ascent pawl 4020 is rotatably mounted about pivot 4005, and comprises a first slot engaging protrusion 4024 on one end, and a second slot engaging protrusion 4022 on the opposite end. Ascent pawl 4020 is arranged within carriage 40 at a position next to a series of engagement holes 202 provided within the rear plate 206 of guide rail 20. First and second protrusions 4022 and 4024 are shaped so as to engage into the engagement holes 202. More particularly, first protrusion 4024 is shaped so as to engage in the engagement holes 202 so as to ratchet from hole to hole when the carriage is moved in an up direction, but to prevent movement of the carriage in a down direction, when engaged. Similarly, second protrusion 4022 is oppositely shaped, so as to allow a ratcheting of the carriage from hole to hole in a downwards direction, and to prevent movement of the carriage in an upwards direction along the rail, when engaged.

Directional selector buttons 4050 and 4060 are provided which may be selectively depressed by a user one at a time, to select the direction of movement of the carriage 40. Depression of either button 4050 or 4060 causes rotation of the ascent pawl 4020 about pivot 4005, to engage either first protrusion 4024 (on depression of button 4060), or second protrusion 4022 (on depression of button 4050) within the series of engagement holes 202 provided in the guide rail. More particularly, depression of button 4050 causes the button to abut against an upward end of pawl 4020, pressing protrusion 4022 into the engagement holes. Conversely, depression of button 4060 causes the button to abut against a downward end of ascent pawl 4020, causing protrusion 4024 to engage with said engagement holes 202. It will be appreciated that ascent pawl 4020 rocks about pivot 4005, such that only one button 4050 or 4060 may be depressed at any one time, and that one protrusion 4022 or 4024 at any one time will be engaged with the engagement holes 202 in the rail. Leaf spring 4064 is provided between the downward end of ascent pawl 4020 and a fixed wall of the carriage. This spring helps in movement of the pawl 4020 about pivot 4004, forming an over-centre mechanism such that ascent pawl 4020 takes one of either the upwards or downwards engaged positions, and does not float between such positions, with neither of the protrusions 4022, or 4024 engaged in the engagement holes 202.

In use the ascent mechanism comprising ascent pawl 4020 provides a ratcheting operation, wherein on an ascent of the guide rail first protrusion 4024 is engaged in the engagement holes 202 and ratchets from hole to hole, as the carriage is moved up the guide rail, by the user pushing on the handle 30. If the user lets go of the handle, first protrusion 4020 does not disengage with the present engagement hole 202 in a downwards direction, and hence the carriage is held in position. In order to make a descent, ascent pawl 4020 is rocked about pivot 4005 by operation of button 4050 such that second protrusion 4022 engages with the engagement holes 202, and ratchets from hole to hole in a downwards direction. Second protrusion 4022 prevents, however, reverse movement of the carriage back in an upwards direction, when the carriage is in descent mode.

The descent control mechanism provided in the carriage 40 will now be described. The purpose of the descent control mechanism is to provide a controlled, incremental descent, between a plurality of intermediate stop positions on the guide rail. The intermediate stop positions are defined by the location of a stop member 28 on the rail 20.

The descent control mechanism comprises a descent pawl 4010 which is pivotably amounted about pivot 4005, the same as the ascent pawl. The descent pawl 4010 is provided at a down end thereof with an abutting surface 4014 provided with a protrusion extending in the direction of the guide rail. The upper end of the descent pawl 4010 is provided with an angled cam surface 4012, comprising a cut out portion of the pawl, as shown in Figures 20, and 24. The cam surface 4012 is contacted by protrusion 424 of the face plate 420 and is angled such that, with reference to Figure 24, movement of protrusion 424 in a downwards direction with respect to the Figure results in movement of the upward end of the pawl in a left hand direction. Translated into Figure 20, face plate 420 pivots about axle 410, such that protrusion 424 moves in a direction into the page. This movement is translated by the cam surface 4012 into a movement of the upper end of the descent pawl about pivot 4005, the upper end moving in a direction down the page, with respect to the Figure. Of course, the opposite end of the descent pawl (the downward end) correspondingly moves in an opposite direction, such that in use the abutting surface 4014 is lifted over any stop member 28.

Also forming part of the descent control mechanism is a handle bar lock member 4040 which is rotatably mounted about pivot 4042 on the carriage member in a downwards direction in front of the ascent and descent pawls. Handle bar lock member 4040 is provided with a slot engaging part 4044, and a stop member engaging part 4046. The slot engaging part 4044 in a resting position rests in slot 422 provided in face plate 420, and acts to stop face plate 420 from being rotated about axle 410. Handle bar lock member 4040 rotates about pivot 4042 to one of two other positions as shown in dashed and dot- dashed outline respectively in Figure 20, dependent upon stop engaging part 4046 contacting a stop member 28 located in the guide rail. In particular, handle bar lock member 4040 assumes one of the two positions other than the rest position depending on whether the stop engaging part 4046 thereof contacts a stop member on upwards directional movement of the carriage 40, or downwards directional movement. More particularly, handle bar lock member 4040 is shaped such that when stop engagement part 4046 thereof contacts a stop member 28 during an upwards movement of the carriage then the handle bar lock member rotates to the position shown in grey in Figure 20 wherein slot engaging part 4044 is fully engaged within the slot, preventing rotation of the face plate 420. Stop engaging part 4046 rotates to trail along the side surface of the slot member as the carriage moves over and past the slot member. Once the handle bar lock member 4040 has moved over the slot member, it returns to a rest position shown in dashed outline by virtue of return spring 4048 acting about pivot 4042.

hi the rest position stop engaging part 4046 points substantially towards the back plate of the guide rail, and slot engaging part 4044 is still retained within slot 422, although rotated at an angle thereof, as shown in dashed relief in Figure 20. However, slot engaging part 4044 still prevents face plate 420 from rotating about axle 410.

hi contrast, when the carriage 40 is in descent mode, the stop engaging part 4046 of the handle bar lock member 4040 engages a stop member 28 from the opposite direction, hi this case, the stop engaging part 4046 causes the handle bar lock member 4040 to rotate in an opposite direction about pivot 4042 than when the stop engaging part engages a stop member in the upwards direction, hi particular the handle bar lock member 4040 is caused to rotate to another position shown in dot-dash outline in Figure 20, wherein the slot engaging part 4044 is rotated so as to be completely out of slot 422 in face plate 420. hi this position, therefore, face plate 420 is free to rotate about axle 410. Once carriage 40 has moved forward past stop member 28 on a downward descent, spring 4048 causes the handle bar lock member 4040 to rotate back to the rest position shown in dashed outline in Figure 20, wherein slot engaging part 4044 re-engages with slot 422, thus preventing rotation of face plate 420.

Also provided as part of the descent control mechanism is down pawl latch 4090. This is pivotably mounted transverse to the pivotal mounting of the ascent and descent pawls, at the upper end of the descent pawl 4010. Down pawl latch 4090 is provided with protrusion 4092 which protrudes into the plane of the stop members 28, and in use contacts and moves over inclined surface 284 of a stop member 28. Down pawl latch 4090 also rests on wire 4112 connecting the carriage 40 to the counter weight, and tension in the wire 4112 causes the down pawl latch to be forced around its pivot in an upward direction (with reference to Figure 24) to contact the underside of descent pawl 4010. The underside of descent pawl 4010 is provided with a notch, into which a corner of down pawl latch 4090 may engage. When down pawl latch 4090 is engaged in the notch provided on the under side of descent pawl 4010, then descent pawl 4010 is held in an inactive position such that abutting surface 4014 at the downward end does not abut against the stopping surfaces 282 of stop members 28. To release the descent pawl from the latched position, as carriage 40 descends past a stop member 28, protrusion 4092 of the down pawl latch 4090 moves over inclined surface 284 of the stop member, thus rotating the down pawl latch 4090 out of the notch provided in the under surface of descent pawl 4010, and releasing the descent pawl to move back such that its downward end abutting surface 4014 is once again in the plane of the stop members 282. This action is particularly guaranteed by the provision of helical spring 4062 acting on the downward end of the descent pawl, to move it back into the stopping position, when the down pawl latch 4090 is released.

In view of the above described arrangement, the operation of the descent control mechanism can be described as follows. Consider first an ascent, and what happens to the elements of the descent control mechanism during such an ascent. In particular, during an ascent at an intermediate position between stop members the handle bar lock member 4040 is in the rest position shown by the dashed lines in Figure 20, with the stop engaging part 4046 pointing towards the rear plate of the guide rail, and the slot engaging part 4040 located within the slot 422, at the slightly inclined position. Thus, the face plate 420 is prevented from rotating, and hence protrusion 424 provided on face plate 420 does not act against cam surface 4012. The descent control mechanism is therefore inoperative at this time, and the carriage 40 can be moved upwards.

As the carriage 40 moves upwards over a stop member, the downward end 4014 of descent pawl 4010 by virtue of the protrusion thereon lifts up and over the stop member, and hence rotates slightly about pivot 4005. Next, stop engaging part 4046 of handle bar lock member 4040 contacts the stop member 28, causing the handle bar lock member 4040 to rotate to the position shown in grey in Figure 20. Here, the slot engaging part 4044 thereof is fully engaged within the slot 422 in the face plate 420. Thus, face plate 420 cannot rotate, even though the carriage 40 is next to a stop member 28.

The above described operations are repeated as the carriage is moved up the guide rail, and moves past each stop member 28. Of course, the ascent control mechanism is in operation during ascent, as previously described.

In order to perform a descent, the ascent control mechanism is switched over via the buttons 4050 and 4060 into descent mode, and the carriage 40 then descends incrementally down the guide rail 20. In particular, consider the carriage 40 descending the guide rail, towards a stop member 28. hi this case, the first part of the descent control mechanism to contact the stop member 28 is the handle bar lock member 4040. hi particular, the stop engaging part 4046 of handle bar lock member 4040 contacts stop member 28, causing the handle bar lock member 4040 to rotate about pivot 4042 to the second position shown in dot dash outline in Figure 20. Here, the slot engaging part 4044 of handle bar lock member 4040 is removed from slot 422 in face plate 420, such that face plate 420 can then rotate about axle 410. With further movement of the carriage 40 in the descent direction, abutting surface 4014 of the downward end of descent pawl 4010 next abuts against stopping face 282 of a stop member 28. This prevents further downward motion of the carriage, and effectively locks the carriage in place. At this point, therefore, face 4014 of descent pawl 4010 is abutted against stopping face 282 of a stop member, and the handle bar lock member 4040 has been rotated out of slot 422 of the face plate 420. However, at the other end of the descent pawl, the down pawl latch 4090 is not yet latched into the slot provided in the under surface of descent pawl 4010.

hi order to release the descent control mechanism to initiate the next incremental descent, the user must apply a force to the descent handle so as to rock the descent handle about axle 410. hi this respect, face plate 420 moves with the descent handle such that rotation of the handle about the axle 410 also causes rotation of the face plate 420 about the axle 410. A rocking motion then applied to the descent handle thus causes the face plate 420 to also rock about axle 410, and causes protrusion 424 provided on the face plate 420 to act against cam surface 4012 of the descent pawl. As described previously, the action of the protrusion 424 on the cam surface 4012 causes the descent pawl to rotate about pivot

4005, such that the abutting surface 4014 on the downward end of the descent pawl is lifted up and over the stopping surface 282 of the stop member. The user can then push on the descent handle to cause the carriage to move towards the next stop member Additionally, in order to hold the descent pawl in place until the carriage has moved past the stop member, the down pawl latch 4090, being forced upwards by tension in the wire 4112 towards the under surface of the descent pawl, latches into the notch provided on the under surface of the descent pawl 4010, when the descent pawl is moved under the cam action. Thus, the down pawl latch acts to latch the descent pawl in a position whereby stopping surface 4014 may move over the stop member 28. Thus, the next incremental descent can then commence.

As the carriage moves over the stop member 28, once the abutting surface 4014 on the downward end of the descent pawl has moved over the stop member completely, as the carriage moves further protrusion 4092 provided on down pawl latch 4090 abuts against inclined surface 284 on stop member 28. The inclined surface of the stop member 28 acting on protrusion 4092 causes the down pawl latch 4090 to rotate about its pivot point against the tension in the wire 4112, which rotation moves the latch from the notch provided in the under surface of the descent pawl 4010. Descent pawl 4010 is then pivoted back about pivot 4005 by the action of spring 4062, such that its abutting surface 4014 on the down end thereof is moved back into the plane of the stop members 28, and can thus engage with stopping surface 282 of the next stop member 28 after the present incremental descent portion has been completed. Additionally, with respect to the handle bar lock member 4040, once this lock member has traversed the stop member 28, then it is rotated by spring 4048 back into the rest position wherein slot engaging part 4044 rests in slot 422, thus preventing rotation of face plate 420, and locking the handle in position.

Thus, the descent control mechanism provides for controlled incremental descent between intermediate stopping positions on the guide rail. In order to overcome any particular stop and initiate the next incremental descent, an intuitive rotary rocking motion is applied by the user to the descent handle, which motion is transferred via face plate 420 so as to release the descent pawl 4010 from engagement from a particular stop member, and thus initiate the next descent portion. The inventors have found that such a mechanism activated by a rotary rocking motion applied to the handle is particularly advantageous, being easy to operate, particularly for users with low manual dexterity. Additional provided within the carriage is a fail safe mechanism comprising fail safe gear 4030, and fail safe latch 4110, attached to wire 4112. Fail safe gear 4030 is pivotably mounted such that the teeth of the gear wheel engage in the engagement holes 202 of the guide rail. In normal use, the fail safe gear freely rotates as the carriage moves up and down the guide rail. In such normal use, fails safe latch 4110 is held rotatably mounted, in a position just to the side of the gear wheel, but out of the circumference of the gear wheel, such that the gear wheel can freely move. However, fail safe latch 4110 is rotatably mounted on the carriage such that it can rotate into the circumference of the gear wheel, thus preventing the gear wheel from turning. As mentioned above, however, fail safe latch 4110 is attached to wire 4112, and the tension in wire 4112 in normal operation keeps the latch 4110 from outside the circumference of the gear wheel 4030.

m the event of the counter weight mechanism failing, however, for example by the wire 4112 snapping, then the tension in wire 4112 will be lost, and a spring 4114 is provided to act on fail safe latch 4110 so as to cause it to be pivoted into the circumference of the fail safe gear 4030. hi particular, spring 4114 applies sufficient force to latch 4110 so as to force the latch in between the gear teeth of fail safe gear 4030, thus preventing the gear from rotating further. Because the teeth of gear wheel 4030 also extend into the engagement holes 202 provided in the guide rail, preventing rotation of the fail safe gear 4030 prevents any further movement of the carriage 40 up or down the guide rail. Thus, in the event of failure of the counter weight mechanism the carriage 40 is locked in position by the fail safe latch 4110 acting on the fail safe gear 4030.

Thus, with the above described mechanisms the carriage provides for hinged mounting of the handle to the carriage such that the handle can be manipulated about several hinged axes of rotation so as to allow the handle to be moved out of the plane of the stairs. Additionally, the ascent and descent control mechanisms provided in the carriage provide for both controlled ascent and descent, and in particular use an intuitive and effective incremental descent mechanism.

Various modifications may be made to the above described arrangement to provide additional embodiments of the invention. For example, whilst in the preferred embodiment described above we have shown the handle as comprising individual ascent and descent bars separately provided so as to be mutually carried by the carrier at the same time, in another embodiment of the invention it may not be necessary to provide both ascent and descent bars at the same time. Instead, the handle could be arranged to be further rotatably mounted such that it can be rotated into an ascent handle position or a descent handle position. In this respect, the ascent handle positions and descent handle positions will preferably be located in the same positions as the ascent handle and descent handles are provided in the preferred embodiment described.

hi another modification the actual arrangement of the ascent handles and descent handles may be varied considerably. Figure 5 mentioned previously gives an alternative configuration of ascent and descent handle which may be used to provide other embodiments, although other shapes of handles will be apparent to the person skilled in the art. The present invention is therefore not limited to any particular shape of ascent or descent handle, and all that is required is that an ascent handle or descent handle be provided, although not necessarily simultaneously, at an appropriate position in front of the user to allow the user to use the apparatus safely. As described previously, different positions are required for ascent and descent of the staircase, for the same position of the carriage.

hi a further modification a rewind mechanism may be incorporated to return the carriage bearing the handle to the opposite end of the stairs without the user having to move with the carriage. Such a rewind mechanism would allow a first user to use the apparatus, for example to ascend the stairs, and then the apparatus can be sent down to the bottom of the stairs using the rewind mechanism to allow a second user to ascend the stairs without the first user having to descend with the device. Such a rewind mechanism may, in a simple form, take the place of respective wires extending from winding reels located at the top and bottom of the rail along the length of the rail and attaching to the carriage. A user may then use the winding reels to effectively "reel in" the carriage from either end of the rail. As one winding reel e.g. at the bottom of the staircase is wound so as to reel the carriage to the bottom of the stairs, the reel at the top of the stairs would reel out, and vice versa. To keep the rewind wires taut, preferably the winding reels are spring-loaded in opposite directions. Moreover, by using different strength springs in the respective winding reels, the carriage can be caused to move automatically to one of the top or bottom of the stairs, depending on which of the reels is provided with the stronger spring. An alternative rewind mechanism may make use of the counterweight mechanism. In particular, in a typical embodiment counterweight wire 4112 will loop over the upper end of rail 20 to connect from the counterweight 26 to the carriage 40. Preferably a pulley wheel is provided at the upper end of rail 20 about which the wire 4112 loops. As an alternative rewind mechanism, therefore, provision of a mechanism to allow rotation of the pulley wheel to be controlled should allow automatic movement of the carriage, as the wire 4112 is moved by the powered pulley wheel. Conveniently, the pulley wheel may be powered by an electric motor, allowing easy control of the rotation of the pulley wheel, and therefore movement of the carriage.

Furthermore, although we have described in detail the preferred presently known best mode ascent and descent control mechanisms provided in the carriage 40, it should be understood that various other mechanisms providing the same functionality will be apparent to the person skilled in the art, and which may be used to provide further embodiments of the present invention. Moreover, although we have described a mechanical arrangement which requires no external power, in other embodiments an electrical control mechanism may be employed, for example using electric motors to help the user move the handle and carriage up and down the guide rail. Other powered mechanisms, for example hydraulic or pneumatic, may also be possible.

Various further modifications will be apparent to the person skilled in the art to provide further embodiments of the invention, which are intended to be encompassed by the appended claims.

Claims

1. An apparatus to aid the traversal of a staircase by a user, comprising: a guide means provided generally parallel to the inclination of the staircase; a carriage slidably engaged with said guide means; and a handle carried by said carriage, said apparatus being characterised by further comprising a control mechanism comprises means for permitting incremental movement along said guide means, the means being further arranged such that initiation of an increment of movement is caused by a user exerting an activation force on said handle whereby to move said handle in a predetermined activation direction.

2. An apparatus according to claim 1, wherein said handle extends from a pivotable connection to said carriage, whereby the activation force causes said ascent handle to rotate about said pivot, said rotation initiating an increment of descent.

3. An apparatus according to claims 1 or 2, wherein said means for permitting incremental movement comprise a pawl, said guide means being provided along its length with a plurality of stop members, the spacing of the stop members defining the movement increments, said pawl being arranged to abut against a stop member at the end of a movement increment whereby to halt said movement, said means for permitting incremental movement further comprising pawl unlatching means responsive to the movement of said handle in the activation direction to unlatch said pawl from said stop member to permit a next incremental movement.

4. An apparatus according to claim 3, wherein said pawl unlatching means comprise a cam surface provided on the descent pawl at an opposite end to that which abuts a stop member, and a cam engaging part which moves in said activation direction on movement of said handle, the movement of said cam engaging part causing, via said cam surface, movement of said pawl whereby to unlatch said pawl from said stop member.

5. An apparatus according to any of claims 1 to 4, wherein the movement is a descent of the staircase.

6. An apparatus to aid the ascent or descent of a staircase by a user, comprising: a guide means provided generally parallel to the inclination of the staircase; and a carriage slidably engaged with said guide means; said apparatus being characterised by further comprising a handle providing, for an ascent of the staircase, an ascent handle, and, for a descent of the staircase, a descent handle, the ascent handle and descent handle being located, for the same position of the carriage, at different positions.

7. An apparatus according to claim 6, wherein said handle comprises said ascent handle and said descent handle separately provided, so as to be mutually carried by said carriage.

8. An apparatus according to claim 6 or 7, wherein said ascent handle is provided on said carriage extending into a position so as to be accessible to the front of a user during an ascent of the staircase.

9. An apparatus according to any of claims 6 to 8, wherein said descent handle is provided on said carriage extending into a position so as to be accessible to the front of a user during a descent of the staircase.

10. An apparatus according to any of claims 6 to 9, wherein said ascent and descent handles are mounted on said carriage so as to extend in substantially opposite directions, whereby to define a user space between said handles in which to accommodate a user when in use.

11. An apparatus according to any of claims 6 to 10, wherein the ascent and/or descent handle is generally curved in shape.

12. An apparatus according to any of claims 6 to 11, wherein the ascent and/or descent handles are rotatably connected to said carriage, whereby to allow said handles to be rotatably moved with respect to said carriage about at least one axis of rotation.

13. An apparatus according to claim 12, wherein said ascent and/or descent handles are rotatably connected to said carriage, whereby to allow said handle to be rotatably moved with respect to said carriage about at least two axes of rotation.

14. An apparatus according to claims 12 or 13, wherein said ascent and/or descent handles are rotatably connected to said carriage, whereby to allow said handle to be rotatably moved with respect to said carriage about at least three axes of rotation.

15. An apparatus according to claims 13 or 14, wherein said axes of rotation are substantially orthogonal.

16. An apparatus according to any of claims 6 to 15, wherein said carrier comprises an ascent control mechanism and a descent control mechanism.

17. An apparatus according to claim 16, wherein said guide means is provided along its length with a series of engagement holes, and said ascent control mechanism comprises an ascent pawl arranged to ratchet along said series of engagement holes during an ascent.

18. An apparatus according to claim 16, wherein said descent mechanism comprises means for permitting incremental descent along said guide means, the means being further arranged such that initiation of an increment of descent is caused by a user exerting an activation force on said descent handle whereby to move said descent handle in a predetermined activation direction.

19. An apparatus according to claim 18, wherein said descent handle extends from a pivotable connection to said carriage, whereby the activation force causes said ascent handle to rotate about said pivot, said rotation initiating an increment of descent.

20. An apparatus according to claims 18 or 19, wherein said means for permitting incremental descent comprise a descent pawl, said guide means being provided along its length with a plurality of stop members, the spacing of the stop members defining the descent increments, said descent pawl being arranged to abut against a stop member at the end of a descent increment whereby to halt said descent, said means for permitting incremental descent further comprising descent pawl unlatching means responsive to the movement of said descent handle in the activation direction to unlatch said descent pawl from said stop member to permit a next incremental descent.

21. An apparatus according to claim 20, wherein said descent pawl unlatching means comprise a cam surface provided on the descent pawl at an opposite end to that which abuts a stop member, and a cam engaging part which moves in said activation direction on movement of said descent handle, the movement of said cam engaging part causing, via said cam surface, movement of said descent pawl whereby to unlatch said descent pawl from said stop member.

22. An apparatus according to any of claims 6 to 21, and further comprising a counterweight slidably attached to said guide means, and arranged to counterbalance the carriage and handle.

23. An apparatus according claim 22, further comprising a fail-safe mechanism to lock movement of said carriage along said guide means in the event that said counterweight fails to counterbalance said carriage and handle.

24. An apparatus substantially as hereinbefore described with reference to Figures 4 to 26.