Patent Description:
A stairlift is a safety-critical apparatus used by persons having at least some degree of disability. As with all mechanical and electro-mechanical devices a stairlift is susceptible to malfunction and, given the potential limitations of some stairlift users, considerable effort is applied to ensure that users are not exposed to unnecessary danger when a malfunction occurs. Further, when a fault does occur, it is important that the fault is quickly identified and addressed.

It is known to provide a visual display on the stairlift in which codes representative of particular faults are displayed but these are principally for the benefit of technicians or service centres responsible for the servicing or upkeep of the stairlift, and are of no immediate assistance to a stairlift user. In our experience, typical stairlift users, and persons having limited technical understanding, find the observation and interpretation of fault codes difficult and confusing.

An advance on the mere display of fault codes is described in <CIT> in which a stairlift is provided with a facility to monitor the operation of the stairlift, to sense a fault, and to communicate the nature of a fault to a remote service centre by way of an SMS message. Again this system is of assistance to service providers but provides no immediate assistance to a stairlift user.

The occurrence of faults is one issue but in some instances what a user perceives to be a fault is not, in fact, a fault. For example, a user may board the stairlift, operate the hand control to start the carriage moving along the rail, only to find that the carriage does not move. This may be indicative of a fault but experience indicates that, in many instances, the problem arises because one of the isolating switches is in the off position. A further example is when a user unwittingly releases pressure on the hand control mid-journey causing the carriage to come to a halt at some point along the rail, spaced from the ends. There have been instances where the user interprets this event as the onset of a fault, does not re-activate the hand control, and attempts to dismount the stairlift. This can be extremely dangerous as any attempt to dismount the stairlift mid-journey exposes the user to the possibility of a dangerous fall.

<CIT> discloses a safety rail monitoring system where a signal is generated as to whether a user is holding onto a safety rail and if the user is not holding onto the safety rail an alert signal is generated to remind the user.

It is an object of the present invention to provide a stairlift, that will go at least some way to addressing the aforementioned drawbacks; or which will at least provide a novel and useful choice.

Accordingly, the invention provides a stairlift as defined in claim <NUM>.

Preferably said diagnostic facility is configured to delay issuing a voice-based output for a defined period following a detection of a fault.

Preferably said defined period varies according to the nature of the detected fault.

Preferably one voice-based output is linked with a further voice-based output a non-verbal audio output and/or a haptic output.

Preferably said stairlift includes an upper stop point at an upper end of the rail and a lower stop point at a lower end of the rail, wherein a fault comprises the carriage coming to a halt between said upper stop point and said lower stop point in response to said user control assuming an off position, and wherein said diagnostic facility is configured to issue a voice-based output comprising an instruction to a user to displace the user control into an operating position to effect movement of said carriage toward a stop point and wherein said diagnostic facility is further configured to issue a voice-based output comprising an instruction to a user not to dismount from the stairlift until arrival at a stop point.

Preferably said stairlift further includes a chair occupancy sensor and wherein said diagnostic facility is configured to issue an instruction to a user not to dismount from the stairlift in response to a signal from said chair occupancy sensor.

Preferably a fault comprises the carriage failing to move or coming to a halt while the user control is in an operating position, and wherein said diagnostic facility is configured to issue a voice-based output comprising an instruction to a user to communicate with a help provider, and wherein said diagnostic facility is further configured to issue a voice-based output comprising an instruction to a user of a procedure to dismount from the stairlift.

Preferably said stairlift includes safety edges displaceable in the event said carriage encounters an obstruction while moving along said rail, wherein a fault comprises the carriage failing to move or coming to a halt while said user control is in an operating position and a safety pad is displaced by contact with an obstruction, and wherein said diagnostic facility is configured to issue a voice-based output comprising an instruction to remove an obstruction to thereby release the safety pad; or to drive the carriage in a reverse direction away from the obstruction.

Preferably said stairlift includes one or more of a carriage isolation switch, a bi-stable switch and a key switch, each of said switches having an 'on' position and an 'off position, any of said switches when in an off position preventing said carriage from movement along the rail, wherein a fault comprises a switch being in an off position while said user control is displaced to an operating position, and wherein said diagnostic facility is configured to issue a voice-based output instructing a user to displace said switch to an 'on' position, and wherein said diagnostic facility is further configured to issue a voice-based output directing a user to a location of a switch, the position of which is preventing movement of said carriage.

Preferably said diagnostic facility includes an input representative of a voltage level of a battery provided to power said carriage along said rail, and wherein a fault comprises said voltage level being below a target voltage level when said user control is in an operating position, said diagnostic facility being configured to issue voice-based output instructing a user to displace the user control to drive the carriage to a charging point on said rail.

Preferably said stairlift further includes a battery charger operable to charge one or more batteries within said carriage and said diagnostic facility includes an input representative of the operation of said charger, wherein a fault comprises no charging power being sensed when said carriage is parked on a charging point on said rail, and wherein said diagnostic facility is configured to issue voice-based output instructing a user to check the connection of said charger to mains power.

Preferably said stairlift further includes a swivel mechanism between said chair and said carriage operable to enable said chair to be swivelled between a central travel position and a swivelled position when said carriage is at a said stop point, wherein a fault comprises said user control being displaced into an operating position when said chair is in a position other than the central position, and wherein said diagnostic facility is configured to issue a voice-based output instructing a user to move the chair to the central position.

Preferably said stairlift further includes a seatbelt operable to retain a user in the chair, said seatbelt having a fastened and an unfastened state, wherein a fault comprises said hand control being displaced into an operating position while said seat belt is in an unfastened state, wherein said diagnostic facility is configured to issue a voice-based message instructing a user to move the seatbelt into a fastened state.

Preferably said diagnostic facility is further configured to issue a non-verbal audible sound characteristic of the presence of a fault.

Preferably said diagnostic facility is configured to receive communications from a remote communication device including a mobile telephone, tablet or other and to issue voice-based outputs in response to communications from said remote communication device. Preferably said diagnostic facility is configured such that one or more of the tone, volume and frequency of voice-based outputs are adapted to the needs or wishes of a user and/or said diagnostic facility is configured to receive operating upgrades from a remote location. Many variations in the way the present invention can be performed will present themselves to those skilled in the art.

One working embodiment of the invention will now be described with reference to the accompanying drawing in which <FIG> shows a stairlift in diagrammatic form to which the present invention may be applied.

<FIG> shows a stairlift to which the present invention may be applied either in whole or in part. Further, subject to the scope of the appended claims, further voice-based outputs not presently described may be provided without departing from the scope of this invention.

In the example shown the stairlift <NUM> comprises a carriage <NUM> mounted on rail <NUM> for movement on the carriage between an upper stop point <NUM> and a lower stop point <NUM>. The carriage <NUM> is driven along the rail by an electric motor <NUM> rotating a pinion <NUM> which engages with a rack <NUM> extending along the underside of the rail. The motor <NUM> draws its operating power from one or more batteries <NUM> mounted in the carriage <NUM>, the batteries <NUM> being charged from battery charger <NUM> and charging connections typically included in, or mounted at, the stop points <NUM> and <NUM>. The charger <NUM> may be connected to mains supply by cable <NUM> connected into wall socket <NUM>.

In the conventional manner a chair <NUM> is mounted on the carriage <NUM> by way of an interface <NUM> and, in this example, a swivel mechanism <NUM> operated by paddle levers <NUM>. The chair comprises a seat base <NUM>, backrest <NUM> and spaced armrests <NUM>. A footrest <NUM> is mounted on the lower edge of the interface <NUM>. A hand control <NUM> is mounted on one of the armrests <NUM> whereby a user can control the movement of the carriage up and down the rail. As typically encountered a user control, preferably a hand control <NUM>, has an off position and an operating position, an internal spring bias causing the hand control to assume the off position when a user releases pressure from the hand control when in an operating position.

The user control is typically supplemented by landing controls (not shown) whereby the stairlift can be called from a one landing when it is parked at another landing. Safety pads <NUM> are provided on the carriage and preferably on the footrest <NUM> which, in the event an obstruction is encountered as the carriage moves along the rail, displace and trigger switches to bring the carriage to a halt. In this particular example an occupancy sensor in the form of a pressure sensitive pad <NUM> is provided in the seat base <NUM> and, in the known manner, the chair is also provided with a seatbelt <NUM> to retain a user in the chair during travel.

In order to prevent unauthorized use of the stairlift and/or to preserve battery charge a number of switches are provided on the stairlift. These may comprise an isolation switch or child lock <NUM> and a bi-stable on/off switch <NUM>. The isolation switch <NUM> is preferably a key switch.

The functioning of the stairlift is preferably under the control of electronic control unit (ECU) <NUM>. The ECU <NUM> receives inputs from the hand control <NUM>, the safety pads <NUM>, the swivel mechanism <NUM>, the charging points at stops <NUM> and <NUM>, the batteries <NUM>, seat belt <NUM> and the switches <NUM> and <NUM>. In accordance with the invention a diagnostic facility is provided, preferably within ECU <NUM>, the diagnostic facility being configured to issue a plurality of voice-based instructions related to a corresponding plurality of faults that might arise during operation. In this context and according to the invention a fault may be an internal or hard fault in a component of the stairlift, or may be a fault due to an operating error by a user. As will be described in greater detail below, should a fault arise the ECU then outputs a voice-based instruction to a user to direct the user to action that may mitigate the effects of the fault. By way of example, the voice-based messages may take the form of pre-recorded messages or may be generated using a voice synthesizer.

In this context reference to the ECU or diagnostic facility issuing, emitting or outputting signals and voice-based messages should be interpreted as including the ECU or diagnostic facility causing signals or messages to be issued, emitted or outputted since the messages may be stored or created by a separate unit, albeit a unit responding to commands from the ECU <NUM>.

The ECU <NUM> is preferably configured to apply a short delay, for example <NUM> to <NUM> seconds, before outputting the voice-based instruction. This delay may vary according to the nature of the fault arising. The voice-based message may be preceded by a non-verbal audible sound and/or a haptic output indicating that a fault has arisen that requires the attention of the user, thereby alerting the user to listen for a voice-based instruction.

Examples of faults may include, (but not be limited to):.

Further, as will be illustrated below, the ECU may be configured to provide layers of outputs. In other words, a first fault may give rise to a first verbal output that elicits a first response from a user. Depending on the response made by the user, or the state in which the stairlift is then placed, the ECU may determine the presence of a second fault that gives rise to a second verbal output. One example of this is illustrated in Operating State <NUM> described below.

Each of the above states may, though not necessarily exactly as described, be addressed as follows:.

Carriage <NUM> comes to a halt before arriving at a stop point <NUM> or <NUM> as a result of a user releasing hand control <NUM> thus allowing the hand control to assume an 'off' position.

After <NUM> seconds of no input from the hand control or from a landing control the ECU <NUM> issues a voice-based message such as:
"You have let go of the arm control. Please move and hold the arm control in the direction you wish to travel until we reach the arrival point.

The carriage <NUM> is not positioned at a rail end at a stop point <NUM> or <NUM> and a user tries to stand as sensed, for example, by the release of loading on pressure pad <NUM>.

The ECU issues a voice-based instruction such as:
"We're not there yet, please remain seated and travel to the arrival point.

Once the user is seated again as sensed by the pressure pad <NUM>, operating state <NUM> is again assumed and, if the hand control has not then been displaced after the stated delay, a further instruction as in Operating State <NUM> is given.

A safety pad <NUM> is activated (displaced). This may arise when the carriage is moving along the rail or when the carriage is halted and the hand control <NUM> is displaced to an 'on' position to initiate movement. The control doesn't need to be released for the instruction to start.

As a first step the ECU emits an audible signal indicating an error or the presence of an event requiring attention. After, say, a <NUM> second delay the ECU <NUM> then issues a voice-based instruction such as:
"An object is blocking my way, please remove it if safe to do so, or travel the other way.

The stairlift will not operate when the carriage is at rest and hand control <NUM> is <NUM> operated, due to a hard fault; a fault that a user cannot resolve.

Upon the control <NUM> or a landing control being moved to an 'on' position the ECU will emit an audible error sound followed by a voice-based instruction such as:
"Sorry, I need some assistance. Please contact your supplier. You can do this <NUM> using your mobile application or by using the telephone number written on the side of your carriage.

The stairlift stops during travel with the hand control <NUM> in an 'on' position, due to hard fault; a fault that a user cannot resolve.

Upon stopping the ECU <NUM> emits an audible error sound followed by a voice-based instruction such as:
"Sorry, I'm experiencing an issue and have stopped working. Ask another person in the house to assist you dismount if possible. If not, use the swivel lever to your side and swivel the chair towards the staircase, dismount with care then contact your supplier to inform them about this issue.

If chair is still in the travel or central position after <NUM> seconds, the ECU issues a further voice-based instruction such as:
"Swivel the chair towards the staircase using the lever to your side. I have stopped working and you will need to raise help or dismount.

The last instruction can be repeated until the ECU receives an input that the swivel <NUM> has been moved from the centre position and the seat pad <NUM> is unloaded.

Isolation switch <NUM> on carriage is in the 'off' position; the carriage will not move.

Upon the hand control <NUM> being moved to an 'on' position, or a call being made from a landing control, the ECU emits an audible error sound followed by a voice-based message such as:
"You have put me in isolation mode. Please press the power button on the back of the carriage to reactivate.

Bi-stable switch <NUM> is in off position; carriage will not respond to an input from the hand control <NUM>, or from a call made from a landing control.

Upon the hand control <NUM> being moved to an 'on' position, or a call being made from a landing control the ECU emits an audible error sound followed by a voice-based message such as:
"You have put me in isolation mode. Please press the power button on the arm rest to reactivate.

No charging current is flowing to the carriage <NUM> when parked at a stop point <NUM> or <NUM>.

After a delay of, say, <NUM> seconds after carriage reaches a stop point, the ECU emits an audible error sound followed by voice-based instruction to issue such as:
"Sorry, my charger needs assistance. Please make sure I'm plugged in and the wall socket is switched on to avoid low battery.

This message may be repeated at defined intervals of, say, <NUM> minute if the operating state persists.

The battery voltage falls below a specified minimum voltage when the hand control <NUM> is displaced to an 'on' position, or the battery voltage is already below the specified target level when the hand control is activated.

The ECU emits an audible error sound and then, if the hand control is not released after, say, <NUM> seconds a voice-based instruction issues such as:
"My batteries are low, please travel downstairs and allow me to recharge.

In this state the stairlift will not respond to a call or command for the carriage to move in an uphill direction. The error sound and above message will be repeated.

On arrival at a stop point the ECU issues a voice-based message such as:
"Thank you, I'm now recharging please contact your supplier to inform them about this issue.

The stairlift does not respond to the hand control <NUM> because the chair <NUM> is not locked in a travel position. Typically the travel position is a central position of the swivel mechanism <NUM>.

In this instance, when the hand control <NUM> is displaced into an 'on' position the ECU will emit an audible error sound followed by a voice-based instruction such as:
"Please make sure the chair is in the travel position by using the levers to your sides. Rotate the chair towards the stairs until it reaches the stop, then release the levers.

The chair <NUM> is fitted with interlock seat belt <NUM> and seat belt is not secured when the hand control <NUM> is displaced to an 'on' position.

The ECU emits an audible error signal followed, after a short delay, by a voice-based message such as:
"Please fasten your seatbelt.

The stairlift does not respond to the hand control <NUM> when no load is sensed by the pressure pad <NUM> or when an armrest is in a folded (up) position.

The ECU emits an audible error signal followed, after a short delay, by a voice-based message such as:
"Please make sure you are seated and both arm rests are in the down position.

The instruction is repeated if the problem continues for a specified period of time.

In addition to providing the diagnostic facility described above, the ECU <NUM> is preferably configured to communicate with one or more remote communication devices such as, for example, a mobile phone, tablet computer or other computing device. When so configured, the diagnostic facility may be modified or updated but also, communications may be transferred from remote sites to a user. Examples of voice-based messages that can be issued following an external communication can include:.

The control facility can also be configured to act in a two-way manner and be provided with a microphone so that a user may send voice-based messages.

The control facility is preferably configured to allow customization to a user's needs or wants. For example, the voice output may be adapted to reflect gender, ethnicity, age and the like. Further, the tone, volume and frequency of the outputs may be varied.

Claim 1:
A stairlift (<NUM>) including a rail (<NUM>); a carriage (<NUM>) displaceable along said rail; a user control (<NUM>) displaceable by a user to effect movement of said carriage along said rail; and a diagnostic facility configured to detect faults in a component of the stairlift and a fault due to an operating error by a user arising in the operation of the stairlift, wherein said diagnostic facility (<NUM>) is further configured to identify the nature of the fault and to issue to a stairlift user a voice-based output comprising a suggestion or instruction to aid a user in responding to the detected fault.