Abstract
There is provided a stair assistance device 1 for assisting a person to climb up and down stairs, the device comprising: a handle; a saddle for engagement with a guide rail mounted alongside the stairs, the saddle being connected to the handle; and an engagement rack for attachment to and extending along the length of the guide rail, the saddle being engaged with the engagement rack; where the saddle is arranged for sliding motion along the guide rail and for selectively preventing motion of the handle and saddle along the guide rail, the saddle comprising: a releasable ratchet mechanism comprising a pawl engageable with a ratchet which, when engaged, prevents movement of the handle in a downstairs direction and allows movement of the handle in an upstairs direction; and where the handle is coupled to the pawl such that a predetermined movement of the handle relative to the guide rail will disengage the pawl.
Claims
1: A stair assistance device for assisting a person to climb up and down stairs, the device comprising: a handle; a saddle for engagement with a guide rail mounted alongside the stairs, the saddle being connected to the handle; and an engagement rack for attachment to and extending along the length of the guide rail, the saddle being engaged with the engagement rack; wherein the saddle is arranged for sliding motion along the guide rail and for selectively preventing motion of the handle and saddle along the guide rail, the saddle comprising: a releasable ratchet mechanism comprising a pawl engageable with a ratchet which, when engaged, prevents movement of the handle in a downstairs direction and allows movement of the handle in an upstairs direction; and wherein the handle is coupled to the pawl such that a predetermined movement of the handle relative to the guide rail will disengage the pawl.
2: The stair assistance device as claimed in claim 1, wherein the engagement rack comprises a strip of generally rigid material with teeth spaced along the strip, and wherein the saddle comprises a sprocket, wherein teeth of the sprocket are arranged to interlock with the teeth of the engagement rack.
3: The stair assistance device as claimed in claim 1, wherein the ratchet is a ratchet wheel comprising angled teeth spaced around the circumference of the ratchet wheel, and wherein the pawl comprises a finger arranged to engage with the angled teeth.
4: The stair assistance device as claimed in claim 3, wherein the ratchet wheel and the sprocket are mounted to a common axle such that rotation of the sprocket and rotation of the ratchet wheel is synchronised.
5: The stair assistance device as claimed in claim 1, comprising a friction clutch mechanism coupled to the ratchet mechanism, the friction clutch mechanism including a clutch lever configured to disengage the pawl when the handle is moved in the upstairs direction and to engage the pawl when the handle is moved in the downstairs direction, wherein the predetermined movement of the handle prevents the clutch lever from engaging the pawl.
6: The stair assistance device as claimed in claim 5, wherein the ratchet is a ratchet wheel comprising angled teeth spaced around the circumference of the ratchet wheel, and the friction clutch mechanism comprises a clutch disc arranged to be frictionally driven by the ratchet wheel.
7: The stair assistance device as claimed in claim 6, comprising a friction washer in contact with and arranged between the ratchet wheel and the clutch disc.
8: The stair assistance device as claimed in claim 6, wherein the clutch disc is arranged to actuate the clutch lever to engage or disengage the pawl based on rotation of the ratchet wheel.
9: The stair assistance device as claimed in claim 8, wherein a first end of the clutch lever is fixed to or integrally formed with the pawl and a second end of the clutch lever is coupled to the clutch disc, wherein the second end of the clutch lever is seated in a notch in the circumference of the clutch disc.
10: The stair assistance device as claimed in any of claim 5, wherein the angle between the clutch lever and the pawl is fixed.
11: The stair assistance device as claimed in claim 1, wherein the saddle comprises a ratchet pull element arranged such that, in a first position of the ratchet pull element, the pawl can move freely between the engaged and disengaged position and, in a second position of the pull element, the ratchet pull element retains the pawl in the disengaged position.
12: The stair assistance device as claimed in claim 11, wherein the ratchet pull element has an elongated shape comprising a flange at one end, wherein, in the second position, the flange obstructs movement of the pawl.
13: The stair assistance device as claimed in claim 11, wherein the predetermined movement is a lifting of the handle to rotate the handle about the long axis of the guide rail to move the ratchet pull element from the first position to the second position and thereby disengage the pawl.
14: The stair assistance device as claimed in claim 1, wherein the saddle comprises a biasing element arranged to bias the pawl into engagement with the ratchet.
15: The stair assistance device as claimed in claim 1, comprising a folding mechanism that enables the handle to be folded away.
16: The stair assistance device as claimed in claim 15, wherein the folding mechanism comprises a single rotating joint that couples the handle to the saddle, with the rotating joint being mounted to the saddle to provide a rotation of the handle, the rotation including a component of rotation about a vertical axis.
17: The stair assistance device as claimed in claim 16, wherein the folding mechanism comprises a spring lock which prevents rotation of the handle until it is disengaged, wherein the spring lock automatically engages when the handle is in a position for normal use and optionally engages when the handle is in the folded position.
18: The stair assistance device as claimed in claim 17, wherein the spring lock comprises a releasable rod extending through the handle and engaging with the rotating joint, wherein a first end of the rod is coupled to an actuation lever for disengaging the rod.
19: The stair assistance device as claimed in claim 1, wherein the saddle can be installed on both a left-hand side and a right-hand side of the stairs.
20: The stair assistance device as claimed in claim 1, wherein the saddle comprises a frame assembly including one or more frames arranged for slidable movement along the guide rail.
21: The stair assistance device as claimed in claim 20, wherein the frame assembly comprises a main frame arranged to house the ratchet mechanism and the friction clutch mechanism, and at least one side frame adjacent and coupled to the main frame.
22: The stair assistance device as claimed in claim 21, wherein the saddle is configured to permit articulation of the main frame and the at least one side frame.
23: The stair assistance device as claimed in claim 1, wherein the stair assistance device comprises the guide rail, wherein the guide rail optionally includes at least one internal channel extending therethrough.
24: The stair assistance device as claimed in claim 23, comprising at least two guide rails, wherein the guide rails are connected by a rail-connecting component inserted into the channel of each guide rail.
25: The stair assistance device as claimed in claim 1, wherein the handle comprises a central gripping portion and one or more lateral gripping portions extending vertically outwards from the central gripping portion.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] Certain preferred embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which:
[0045] FIG. 1 shows a stair assistance device;
[0046] FIG. 2 shows a close up view of the saddle and guide rail;
[0047] FIG. 3 shows the sprocket and engagement rack;
[0048] FIG. 4 shows the ratchet mechanism and friction clutch mechanism in an engaged position;
[0049] FIG. 5 is a sequence of diagrams showing how the ratchet mechanism and friction clutch mechanism operate during an upstairs movement along the guide rail;
[0050] FIG. 6 is a sequence of diagrams showing how the ratchet mechanism and friction clutch mechanism operate during a downstairs movement along the guide rail;
[0051] FIG. 7 shows how the handle can be moved to permanently disengage the pawl;
[0052] FIG. 8 is a sequence of diagrams showing the ratchet mechanism and friction clutch mechanism when the handle is used to permanently disengage the pawl;
[0053] FIG. 9 shows the handle;
[0054] FIGS. 10 and 11 show a top and side view of the handle unlocking mechanism which enables the handle to be folded away;
[0055] FIGS. 12 and 13 show how the handle can be prevented from disengaging the pawl when the handle is in the folded position;
[0056] FIGS. 14, 15 and 16 show the back of the saddle with a frame assembly that enables the saddle to move around bends;
[0057] FIG. 17 shows the internal structure of the guide rail;
[0058] FIG. 18 shows rail-connecting components for connecting two guide rails;
[0059] FIGS. 19 and 20 show how a bracket is connected to a guide rail;
[0060] FIG. 21 shows a guide rail mounted to a wall by a bracket; and
[0061] FIG. 22 shows a guide rail mounted to the ground by a bracket and a pole.
DETAILED DESCRIPTION
[0062] The stair assistance device 1 of FIG. 1 has three main parts, comprising a handle 2, a saddle 4, and an engagement rack (not visible). The stair assistance device 1 is connected onto a guide rail 8, which is similar in design to a conventional stair rail. The guide rail 8 can be supplied for installation with the stair assistance device 1 or an existing stair rail may be used. The handle 2 is attached to the saddle 4. The stair assistance device 1 also includes a folding mechanism 10, which is located between the saddle 4 and the handle 2, and which is discussed in more detail below. The guide rail 8 extends along a stairway following the stairs 12, and is mounted to a wall of the stairway. As shown in more detail in FIGS. 2 and 3, the engagement rack 6 is attached to and forms part of the guide rail 8, and extends along the length of the guide rail 8.
[0063] FIG. 2 shows a close up of the connection of the saddle 4 to the guide rail 8 and the engagement rack 6. The handle 2 is coupled to the saddle 4 via the folding mechanism. The engagement rack 6 is arranged in a slot in the underside of the guide rail 8. The saddle 4 is fitted to the guide rail 8 using rollers or wheels 14 and hence can slide up or down the guide rail 8. The saddle 4 includes a sprocket 16 which is mounted to and rotatable about an axle 24. The sprocket 16 engages with the engagement rack 6, as shown in closer detail in FIG. 3. The engagement rack 6 comprises a strip of material including a sequence of depressions 18 that form a rack, with the material between the depressions 18 acting as the teeth 20 of the rack. The teeth 22 of the sprocket 16 interlock with the teeth 20 of the engagement rack 6. When the sprocket 16 is able to rotate (e.g. it is not prevented from rotating), the saddle 4 can move along the engagement rack 6 and hence along the guide rail 8. When the sprocket 16 cannot rotate, the saddle 4 cannot move along the engagement rack 6 or the guide rail 8. Thus the saddle 4 can selectively prevent movement of the handle 2 up or down the stairs 12 by preventing rotation of the sprocket 16. This is achieved using a ratchet mechanism 26 and a friction clutch mechanism 28 disposed within the saddle 4, as shown in FIGS. 4 to 6 and described below.
[0064] FIG. 4 shows the ratchet mechanism 26 and the friction clutch mechanism 28 of the saddle 4 which enables the selective prevention of movement of the handle 2. The ratchet mechanism 26 comprises a ratchet wheel 30 and a pawl 32 engageable with the ratchet wheel 30. In FIG. 4, the pawl 32 is in an engaged position in which the pawl 32 is seated between adjacent teeth of the ratchet wheel 30. The pawl 32 is biased into engagement with the ratchet wheel 30 by a ratchet spring 34. The ratchet wheel 30 is mounted to the sprocket axle 24, so that rotation of the sprocket 16 and the ratchet wheel 30 is synchronised.
[0065] The friction clutch mechanism 28 interacts with the ratchet mechanism 26 to engage and disengage the pawl 32 based on rotation of the ratchet wheel 30. The friction clutch mechanism 28 comprises a clutch lever 36, a clutch disc 38, and a clutch spring (not shown). A first end of the clutch lever 36 is seated in a notch 40 in the clutch disc 38, and a second end of the clutch lever 36 is fixed to the pawl 32. In this example the clutch lever 36 is fixed to a protrusion 42 that extends outwardly from the pawl 32, but the components could instead be integrally formed or rigidly connected in other ways. The clutch lever 36 and the pawl 32 define an angle therebetween, which is a fixed angle due to the rigid connection between the pawl 32 and the clutch lever 36. The clutch disc 38 is coupled to the ratchet wheel 30 via a friction disc (not shown).
[0066] The saddle 4 also comprises a ratchet pull spring 44, which is arranged to interact with the pawl 32. In FIG. 4, the ratchet pull spring 44 is in a first position in which the ratchet pull spring 44 does not obstruct movement of the pawl 32. Operation of the ratchet pull spring 44 will be discussed in more detail later.
[0067] In the engaged position of the pawl 32 as shown in FIG. 4, the pawl 32 abuts the ratchet wheel tooth and would prevent downstairs (leftward) movement of the saddle 4. If the saddle 4 moves in an upstairs direction (to the right) then the pawl 32 is rotated into the disengaged position and over the next tooth, as discussed below.
[0068] The sequence of diagrams in FIG. 5 shows the operation of the ratchet mechanism 26 and the friction clutch mechanism 28 as the handle 2 is moved in an upstairs direction (to the right, as indicated by the arrows A1). As the handle 2 is pushed upstairs, the saddle 4 begins to move along the guide rail 8. The sprocket 16 rotates in the direction indicated by the arrow A2 due to interaction with the teeth 20 of the engagement rack 6. This causes the ratchet wheel 30 to rotate about the common sprocket axle 24. As the ratchet wheel 30 rotates, the pawl 32 slides along the angled tooth of the ratchet wheel, thus moving upwards as shown by the arrow A3. As shown in FIG. 5 b), rotation of the ratchet wheel 30 drives the clutch disc 38 to rotate due to friction therebetween. The notch 40 of the clutch disc 38 thus rotates and pushes against the clutch lever 36 seated therein, causing the clutch lever 36 to pivot and to lever the pawl 32 out of engagement. The pawl 32 is hence moved against the force of the ratchet spring 34 by both the angled teeth and the clutch lever 36, and does not restrict motion of the saddle 4 along the engagement rack 6.
[0069] The ratchet spring 34 does not push the pawl 32 into engagement with the next tooth, because the clutch lever 36 holds the pawl 32 in the disengaged position. Thus, during an upstairs motion the saddle 4 and handle 2 move freely up the guide rail 8 and the user can walk up the stairs using the handle 2 for additional balance and stability. Additionally, because the pawl 32 is prevented from re-engaging the ratchet wheel 30 by the friction clutch mechanism 28 during upstairs motion, the undesirable tapping noise caused by the pawl 32 continually engaging subsequent ratchet wheel teeth is eliminated. Moreover, the friction clutch mechanism 28 requires no actuation or input from the user because it relies on a frictional relationship with the ratchet mechanism 26 and hence it has simple operation.
[0070] The sequence of diagrams in FIG. 6 shows the operation of the ratchet mechanism 26 and the friction clutch mechanism 28 as the handle 2 is moved in a downstairs direction (to the left, as indicated by the arrows A4). The sprocket 16 rotates in the direction indicated by the arrow A5, again due to the teeth 20 of the engagement rack 6. This causes the ratchet wheel 30 to rotate about the axle 24. As the ratchet wheel 30 rotates, the pawl 32 is engaged with the ratchet wheel 30 due to the ratchet spring 34 pushing the pawl 32 downwards and by action of the friction clutch mechanism 28. A shown in FIG. 6 b), rotation of the ratchet wheel 30 drives the clutch disc 38 to rotate in the second direction due to friction therebetween. The notch 40 thus moves in the second direction, pushing the clutch lever 36 seated therein and causing the clutch lever 36 to pivot and lever the pawl 32 into engagement. The pawl 32 then restricts further rotation of the ratchet wheel 30. Since rotation of the sprocket 16 and ratchet wheel 30 is synchronised, motion of the sprocket 16 and hence the saddle 4 along the engagement rack 6 is prevented. Thus, if the user becomes unbalanced or falls while moving upstairs, then any downstairs motion of the handle 2 is prevented and the user can stabilise themselves using the handle 2.
[0071] It will be appreciated that a small amount of downstairs motion will occur while the pawl 32 is levered into engagement with the ratchet, but this movement is relatively very small and will not have any effect on the user experience.
[0072] FIGS. 7 and 8 show how a predetermined movement of the handle 2 permits a downstairs movement of the stair assistance device 1. The handle 2 is coupled to the saddle 4 by the folding mechanism 10 which comprises a fold component 46 fastened to the saddle 4. To perform the predetermined movement, the handle 2 should be tilted or lifted as shown by arrow A6. This causes the handle 2 and the fold component 46 to rotate in the direction indicated by arrow A7 about a fold axle 48 of the folding mechanism 10. As shown in FIG. 8, the ratchet pull spring 44 is coupled to the fold component 46. Thus, as the handle 2 is tilted or lifted, the ratchet pull spring 44 is also lifted. During this movement a flange 50 of the ratchet pull spring 44 engages with and applies a pulling force to the pawl 32, thus pulling the pawl 32 out of engagement. While the handle 2 is maintained in the lifted position, the ratchet pull spring 44 will retain the pawl 32 out of engagement by obstructing any movement of the pawl 32. Since the clutch lever 36 is rigidly fixed to the pawl 32, retention of the pawl 32 also prevents the clutch lever 36 or clutch disc 38 from moving, and hence prevents the friction clutch mechanism 28 from actuating the pawl 32. However, due to the frictional coupling between the clutch disc 38 and the ratchet wheel 30, the ratchet wheel 30 can still rotate. Thus, the ratchet wheel 30 and sprocket 16 (via the sprocket axle 24) can rotate freely both clockwise and counter-clockwise. This enables the saddle 4 and handle 2 to move both upwards and downwards along the guide rail 8.
[0073] FIG. 9 shows the handle 2, which comprises a central gripping portion 52 and two lateral gripping portions 54. Each lateral gripping portion 54 includes an upper portion 54a which extends vertically upwards from the central gripping portion 52, and a lower portion 54b which extends vertically downwards from the central gripping portion 52. Each of the upper and lower portions comprises a loop which makes it easier for the user to hold the handle 2.
[0074] The handle 2 is normally locked in the position shown in FIG. 1. In order to fold the handle 2 away, e.g. to save space in the stairway, the handle 2 comprises the folding mechanism 10. The folding mechanism 10 comprises a single rotating joint which permits rotating of the handle about a vertical axis. The rotating joint comprises a fixed portion fixed to the saddle and a rotating portion fixed to the handle and rotatable relative to the fixed portion about the vertical axis. The folding mechanism 10 further comprises an actuation lever 56 and a spring lock comprising a rod 58 extending through the central gripping portion 52 and coupled to the actuation lever 56. In the locked position, a proximal end of the rod 58 extends into a first opening 60a in the fixed portion of the rotating joint which prevents any change in orientation of the handle 2 relative to the saddle 4. When the actuation lever 56 is pressed in a direction toward the guide rail 8, the rod 58 is pulled out of the first opening 60a, thus enabling the handle 2 to be rotated and folded away. When the handle 2 reaches the folded position, which is a position in which a plane of the handle 2 is parallel to the plane of the wall of the stairway, the rod 58 is biased into a second opening 60b in the rotating joint by a spring which thus locks the handle 2 in the folded position.
[0075] FIGS. 12 and 13 show how the stair assistance device 1 can prevent the pawl 32 from being disengaged when the handle 2 is in the folded position. The saddle 4 comprises a protrusion 61 located on a surface of the saddle 4 adjacent to the handle 2, and the handle 2 comprises an aperture 63 located on a surface of the handle 2 which is adjacent to the saddle 4 in the normal position. When the handle 2 is in the normal position, as shown in FIG. 12, the protrusion 61 and the aperture 63 are aligned. When the handle 2 is lifted in the predetermined movement, the protrusion 61 fits into the aperture 63 in the handle 2 and hence does not obstruct lifting of the handle 2. The ratchet pull spring 44 can therefore pull the pawl 32 out of engagement. When the handle 2 is in the folded position as shown in FIG. 13, the protrusion 61 and the aperture 63 are out of alignment. Thus, when the user tries to lift the handle 2, the protrusion 61 abuts the surface of the handle 2 and obstructs its movement, thereby preventing the handle 2 from lifting and thus preventing the ratchet pull spring 44 from disengaging the pawl 32. The pawl 32 is therefore locked in place when the handle 2 is in the folded position.
[0076] FIGS. 14, 15 and 16 show the back side of the saddle 4, i.e. the side opposite to the handle 2. The saddle 4 comprises a frame assembly 62 which provides a support structure to which the various components of the saddle 4 are mounted. The frame assembly 62 comprises a main frame 64 and two side frames 66 located adjacent to and on either side of the main frame 64. Each side frame 66 is connected to the main frame 64 by a fastener 68, and can pivot about the fastener 68. Additionally the side frames 66 are connected to each other via a ball-and-socket type joint 70. The side frames 66 therefore have a degree of articulation/relative movement as compared to rigidly-formed frame assemblies. This enables the frame assembly 62 to accommodate bends in the guide rail 8, while retaining a tight fit to the guide rail 8. Each frame comprises at least one roller or wheel 14 to ensure smooth sliding of the saddle 4 along the rail 8.
[0077] FIG. 17 shows the internal structure of a guide rail 8 which has been adapted for use with the stair assistance device 1. The rail 8 includes four channels 72 extending therethrough: two closed channels 72a and two open channels 72b. The closed channels 72a are sealed except for an opening at each end of the guide rail 8, which permits insertion of cables, rail-connecting components etc. The open channels 72b (also termed slots) are exposed on one side along the length of the rail 8. This can enable the inclusion of components which are required to be accessed externally, such as wall-brackets 76 for mounting the guide rail 8 to a wall, grip strips for providing grip to users of the guide rail 8, the engagement rack 6 of the stair assistance device 1, etc.
[0078] As shown in FIG. 18, two guide rail sections can be joined together using one or more rail-connecting components 74, which in this example are bolts 74. The bolts are sized and shaped to fit into a channel 72 of each rail section with a friction fit. In this way, longer guide rails 8 can be formed, and different shaped sections can be connected to form rails suited to the particular stairway in which they are installed. Two bolts 74 are pictured here, but one or more bolts 74 may be used to connect each pair of guide rail sections.
[0079] FIGS. 19 and 20 illustrate how a bracket 76 for connecting the guide rail 8 to a wall and/or the floor is connected to the rail 8. The bracket 76 includes an insertion portion 78 which fits into a channel 72 of the guide rail 8. The insertion portion 78 is sized and shaped so as to substantially match the contour of the channel 72 to enable insertion thereof while ensuring a close fit. The bracket 76 is then tightened to the guide rail 8 using a bracket-tension component 80. The bracket-tension component 80 includes a body portion which is sized and shaped to substantially match the contour of the channel 72, and a tapered portion 82 which extends from the body portion in a direction along the channel 72. The bracket-tension component 80 is inserted into the channel 72 and the tapered portion 82 enters a narrowing opening in the bracket insertion portion 78. The tapered portion 82 is sized slightly larger than the narrowing opening such that as the tapered portion 82 enters the narrowing opening, the bracket insertion portion 78 expands outwardly against the channel 72 of the guide rail 8. This secures the bracket 76 under tension, creating a secure fit of the bracket 76 to the guide rail 8. The bracket-tension component 80 is then fastened to the bracket 76 using a bolt 84. As the bolt 84 is tightened, the tapered portion 82 will be wedged further inside the narrowing opening, thus increasing the tension of the fit.
[0080] FIG. 21 shows the bracket component being used to mount the guide rail 8 to a wall. As shown in FIG. 21, the bracket 76 is adjustable to provide flexibility in installation, depending on the relative position and orientation of the rail 8 and the wall/ground. The bracket 76 includes a telescopic portion 86 for adjusting the depth of the bracket 76 when the distance between the rail 8 and the wall varies. The telescopic portion 86 includes a first portion slidably engaged within a second portion. The length of the telescopic portion 86 is determined by using a fastener (e.g. a set screw) to set the position of the first portion relative to the second portion. The bracket 76 also includes a rotatable portion 88 for adjusting the angle of the bracket 76 relative to the rail 8. The rotatable portion 88 is rotatably coupled to the telescopic portion 86 and can rotate about an axis defined by the telescopic portion 86. The angle of the rotatable portion 88 is set using a set screw.
[0081] As shown in FIG. 22, the bracket 76 can also be used to mount to guide rail 8 to the ground if there is no suitable wall nearby. The rotatable portion 88 is coupled directly to a pole 90 which extends from the ground.
