EXTENDABLE STAIRCASE

Abstract

 The present invention relates to a modularly extendable staircase (100) comprising a plurality of extendable treads (20), each tread (20) comprising a tread surface (27), characterized in that each tread (20) is configured to be moved from a retracted state (11) to an extended state (12) such that when each tread (20) is arranged in its retracted state (11), the tread surfaces (27) extend in a common extension plane (28), and wherein when the respective tread (20) is arranged in an extended state (12) the tread surface (27) of the respective tread (20) extends parallel to and above a tread surface (27) of a neighboring tread (20).

Description

[0001] The present invention concerns a staircase with modularly extendable treads.

[0002] After a surgery, patients in a hospital typically make their first steps in the hospital itself. Especially after surgeries that affect the ability to walk, climbing stairs constitutes a major challenge for patients. To practice walking and climbing stairs, patients usually first walk along the corridor of the hospital and, after a first successful training, up and down the stairway of the building. This is inconvenient in two aspects. First, the stairway of a hospital is a busy place frequented by patients, visitors and staff moving between different stations of the hospital, which creates stress for the patients. Second, this solution is just a provisional one in the sense that the stairway is not built for this purpose and the treads are not designed to match the patients' needs. A considerable disadvantage of using the building stairways as training area is that patients that require assistance cannot profit from existing body weight support systems, which relieve patients from their body weight and further catch them in case they fall.

[0003] Some hospitals might have dedicated trainings stairs respectively training steps available; however, they are bulky and thereby require a lot of precious space even when they are not in use.

[0004] Based on this, it is subject of the present invention to provide a staircase which is improved regarding the problems described above.

[0005] This objective is solved by a staircase with the features of claim 1 as well as the methods of claims 42 to 45.

[0006] Advantageous embodiments of the invention are given in the corresponding subclaims and described in the following.

[0007] The invention discloses a modularly extendable staircase comprising a plurality of extendable treads, each tread comprising a tread surface, characterized in that each tread is configured to be moved from a retracted state to an extended state such that when each tread is arranged in its retracted state, the tread surfaces extend in a common extension plane, and wherein when the respective tread is arranged in an extended state the tread surface of the respective tread extends parallel to and above a tread surface of a neighboring tread (20).

[0008] In the context of the present invention, the term 'modularly extendable' or 'modular extension' refers to the possibility to extend or retract individual treads of the staircase, i.e. without the need to extract all extendable treads of the staircase. However, the staircase according to the invention also permits to extend or retract all extendable treads of the staircase. The number of extendable treads is arbitrary. The modular design of the staircase is in particular useful for use in hospitals or rehab institutions, as it permits to select a specific number of extended treads depending on the physical constitution of the patient. The staircase according to the invention may however also find applications in other fields, for example as a compact extendable staircase for use in labs, workshops and the like.

[0009] The tread surface refers to the part of the tread a patient or user is stepping on during intended use of the staircase. To this end, the tread surface is preferably arranged horizontally and oriented perpendicular to a vertical gravitational force such that the patient or user does not need to balance or compensate any tilts of the tread surface with respect to a horizontal axis normal to the vertical gravitational force. However, the staircase may also be used on an oblique plane, if the tread surfaces remain normal to the gravitational force.

[0010] The invention advantageously proposes to configure the tread surfaces such that they can be moved between a retracted state and an extended state. In the retracted state, the tread surfaces of the extendable treads extend in a common extension plane, making the staircase compact and easy to store, which is particularly useful when the staircase is not in use. When the tread surface of the respective extendable tread is moved to the extended state above the tread surface of the neighboring tread, the staircase may be used as intended.

[0011] According to an embodiment of the present invention, the staircase may form a cuboid when all treads are in the retracted state. To this end, all extendable treads may be arranged in a static, particularly non-extendable, lowermost tread. The cuboid may for example have a height H, a width W and a length L, wherein the height extends along a vertical z-axis and the width and length extending along an x- and y- axis in a horizontal plane perpendicular to the vertical z-axis, such that the x-, y- and z-axes span an orthogonal coordinate system. In the following, the terms vertical and horizontal refer to orientations relative to the coordinate system defined here.

[0012] The height of the cuboid may correspond to a height of the lowermost tread and the dimensions of the width and length define an area covered by the staircase, particularly covered by the lowermost tread. The dimensions of the cuboid may for example be chosen such that an aspect ratio R = W/L is within 0.2 and 0.8 and that the height H may be within 5 cm and 30 cm. For example, the width may be 1 m, the length may be 1.8 m and the height may be 17 cm. The respective tread surface of a respective tread may for example have a depth between 10 cm and 40 cm, particularly between 20 cm and 30 cm, said depth extending along the length of the staircase, respectively.

[0013] Each extendable tread may comprise a tread height that may be on the order of the height of the lowermost tread or lower, for example between 5cm and 30 cm.

[0014] A structure comprising the respective tread surface of a respective tread may comprise a thickness that may be substantially lower than the tread height of the respective tread, i.e. a thickness smaller than 30cm, particularly smaller than 5 cm.

[0015] Each tread of the staircase may for example comprise six pairwise opposing boundaries defining a volume within the boundaries. For example, the volume defined by the lowermost tread may be approximated by the dimensions of the cuboid, H × W × L. The boundaries may for example be formed by walls of the respective tread. The walls may be closed walls, but they also may comprise holes or openings in general. Opposing boundaries or walls may be oriented parallel to each other, but they may also be oriented at a finite angle with respect to each other. The term 'neighboring' refers to adjacent treads of a respective tread. For example, thread three has the neighboring treads two and four.

[0016] According to another aspect of the present invention, the staircase may comprise at least one guidance unit that may be configured to move the extendable treads between the retracted and the extended state. To this end, the guidance units may be arranged at the extendable treads and configured to be slidable between and fixable at at least a first and a second position. Preferably, the first and second position may correspond to the retracted and the extended state of a respective extendable tread, respectively.

[0017] To move the respective tread surface relative to the tread surfaces of the neighboring treads between the extended and the retracted state, the guidance units may connect the respective extendable tread with its neighboring treads.

[0018] According to an embodiment, the at least one respective guidance unit may be arranged for example on two neighboring walls, particularly vertical neighboring walls of neighboring treads, slidably connecting the neighboring treads. However, the at least one guidance unit may also be mounted on an outside and/or an inside of the respective vertical wall.

[0019] The at least one guidance unit may be arranged vertically, wherein in the first position the respective tread is in the retracted state and wherein in the second position the respective tread is in the extended state. Preferably, the second position is located vertically above the first position.

[0020] According to an embodiment of the present invention, the at least one guidance unit is pivotable around an axis extending within in a horizontal plane spanned by the x- and the y-axis defined above. The axis may for example be parallel to the x-axis or the y-axis, such that the guidance unit may be pivoted around an axis parallel to a front- or backside of the staircase.

[0021] According to another embodiment of the present invention, in the first position, the at least one guidance unit may be arranged essentially horizontally (i.e. parallel to the x- and the y-axis) with the respective tread being in the retracted state. Further, in the second position, the at least one guidance unit may be pivoted around said axis relative to the first position such that the respective tread is in the extended state. As such, the guidance units may be movable between the first and second position and pivotable around said axis so as to move the respective tread between the retracted and the extended state.

[0022] According to another aspect of the present invention, the treads may comprise support struts. The support struts may advantageously be used to stabilize and fix individual treads, particularly in the extended state. To this end, the support struts may for example be mounted on at least one wall of the respective tread, particularly a vertical wall, particularly an outside and/or an inside of the vertical wall.

[0023] According to another embodiment of the present invention, the support struts may be pivotable around at least one respective axis. Said axis is preferably arranged horizontally, particularly parallel to the x-axis. As such, the support struts may form pivotable support struts that may be used to pivot a respective tread between the retracted and the extended state.

[0024] According to yet another embodiment of the present invention, the pivotable support struts connect neighboring treads such that the support struts are pivotable around a first pivot axis and around a second pivot axis. Preferably, in this embodiment, the pivot axes are offset and parallel to each other and parallel to the horizontal plane defined by the x- and y-axis, wherein the first pivot axis runs through a respective extendable tread and wherein the second pivot axis runs through a neighboring tread of the respective tread. As such, the two pivot axes may form a lever that may be used to pivot the respective tread surface of the respective tread between the retracted state and the extended state. Preferably, each two of these levers may be arranged on each of two front sides of a respective tread, so as to enable a stable arrangement of the respective tread surface parallel above the neighboring tread surface.

[0025] According to another embodiment of the present invention, the pivotable support struts may connect neighboring treads such that they are further pivotable around a third pivot axis parallel to the first and second pivot axes, forming double levers configured to pivot the respective tread surface between the extended and retracted state.

[0026] According to another aspect of the present invention, the treads may comprise support blocks. The support blocks may be used to support treads in the extended state by positioning the treads on the support blocks. For example, the neighboring tread may comprise support blocks that may be used to support the extended respective tread. Preferably, the support blocks are used in combination with the guidance units, wherein the guidance units may be used to extend or retract a respective tread and wherein the support blocks are used to support the extended or retracted tread in the extended or retracted state. The support blocks may also be used in combination with the support struts, wherein the support struts may be positioned on the support blocks so as to fix the respective tread in the extended or retracted state.

[0027] The support blocks may for example be mounted on at least one vertical wall of the respective tread. Particularly, the support blocks may be mounted on the inside and/or the outside of the respective vertical wall.

[0028] Another aspect of the present invention refers to extension elements that may be used to extend the respective tread from the retracted state to the extended state via the guidance units and/or the support struts as well as to retract the respective tread from the extended state to the retracted state via the guidance units and/or the support struts.

[0029] For example, the extension elements may comprise recesses arranged on the respective extendable tread area for manual extension of the respective tread from the retracted state to the extended state as well as for manual retraction of the respective tread from the extended state to the retracted state. To this end, the recesses may for example be arranged on the respective tread surfaces or walls of a respective tread.

[0030] As another example, the extension elements may comprise a chain controlled by a chain actuator configured to automatically extend the respective tread from the retracted state to the extended state as well as to automatically retract the respective tread from the extended state to the retracted state.

[0031] As another example, the extension elements may comprise a linear actuator configured to automatically extend the respective tread from the retracted state to the extended state as well as to automatically retract the respective tread from the extended state to the retracted state.

[0032] The linear actuator may further be configured to pivot around a corresponding axis extending along a horizontal axis, particularly an axis parallel to the x-axis. The linear actuator may also be coupled to a lever configured to automatically extend the respective tread from the retracted state to the extended state as well as to automatically retract the respective tread from the extended state to the retracted state.

[0033] As yet another example, the extension elements may comprise a scissor lift controlled by a scissor lift actuator configured to automatically extend the nth tread from the retracted state to the extended state as well as to automatically retract the nth tread from the extended state to the retracted state.

[0034] In another embodiment of the present invention, the staircase may comprise at least one battery for powering the chain actuator, the linear actuator or the scissor lift actuator. Alternatively or additionally, the staircase may comprise an electrical connection, for example at least one cable configured to be connected to an external power supply for powering the chain actuator, the linear actuator or the scissor lift actuator.

[0035] The batteries may be mounted inside the volume defined by the staircase.

[0036] Preferably, the batteries may be configured to be automatically recharged via an external power supply.

[0037] Another aspect of the present invention refers to locking elements for locking or unlocking the respective tread in the extended or the retracted state.

[0038] For example, the locking elements may comprise the pivotable support struts, wherein in the extended state, the pivotable support struts of the respective tread may be arranged vertically and supported by the support blocks of the neighboring tread and wherein in the retracted state, the pivotable support struts of the respective tread may be arranged essentially horizontally, such that the staircase remains compact when all treads are in the retracted state.

[0039] While a vertical orientation of the support struts, i.e. parallel to the gravitational force, in this embodiment may be advantageous in the extended state so as to minimize or avoid a tilt caused by a patient or user stepping on the tread surface of an extended tread, the orientation of the support struts in the retracted state may also deviate from a horizontal orientation depending on the constructive details of the staircase.

[0040] According to another embodiment of the present invention, the locking elements may comprise the pivotable support struts, wherein in the extended state, the respective tread is pivoted into a position beyond a dead center of the pivotable support struts. As such, the respective tread or tread surface may be supported by the tread area of the neighboring tread in the extended state, wherein in the retracted state, the pivotable support struts are arranged essentially horizontally. By positioning the extended tread or tread surface beyond a dead center of the pivotable support struts, the respective extended tread may be advantageously locked in the extended state by supporting it on a respective lower neighboring tread.

[0041] According to an embodiment of the present invention, the pivotable support struts may be formed by at least one of the vertical walls of the respective tread. Preferably, the vertical wall may be arranged at a front side or back side along the length of the staircase, extending along the y-axis. In this embodiment, the respective wall may itself pivotably and arranged essentially vertically in the extended state and non-vertically, particularly essentially horizontally in the retracted state.

[0042] According to another example, the locking elements may comprise the double lever, the aforementioned double lever being configured to pivot the respective tread between the extended state and the retracted state.

[0043] According to another example, locking elements may comprise the pivotable support struts, wherein in the extended state, the pivotable support struts are arranged vertically such that when the staircase is positioned on a lower positioning surface, the pivotable support struts are supported by the lower positioning surface. In the retracted state, the pivotable support struts may for example be arranged essentially horizontally. In this particular embodiment, the support struts of every tread preferably extend from the extended tread vertically downwards to the lower positioning surface, so as to support the extended tread directly on the lower positioning surface. While a vertical orientation of the support struts in this embodiment may be advantageous in the extended state so as to minimize or avoid a tilt of the respective tread caused by a patient or user stepping on the tread surface of an extended tread, the orientation of the support struts in the retracted state may deviate from a horizontal orientation depending on the constructive details of the staircase.

[0044] For example, the locking elements may comprise at least one locking pin.

[0045] According to another example, the locking elements may comprise at least one lifting magnet arranged on the treads. Preferably, the lifting magnet is further configured to engage and extract the locking pin so as to lock and unlock a respective tread in the extended or the retracted state.

[0046] According to another example, the locking elements may comprise at least one pivoting magnet. Preferably, said pivoting magnet may be equipped with the locking pin and configured to pivot the locking pin around a respective axis so as to lock and unlock the respective tread in the extended or in the retracted state.

[0047] According to an embodiment of the present invention, the lifting magnet and/or the pivoting magnet may interact with the aforementioned guidance units such that the lifting magnet or the pivoting magnet may be configured to engage or extract the locking pin into or out of the at least one guidance unit, particularly in an optional through hole of the at least one guidance unit so as to lock the respective tread or tread surface in the extended or the retracted state.

[0048] According to another aspect of the invention, the staircase may comprise at least one force sensor configured to determine the force exerted by a patient stepping on the tread surface of a respective tread.

[0049] According to another aspect of the invention, the staircase may comprise at least one spring configured to reduce a tilting moment acting on the treads, particularly a tilting moment acting when the respective tread is moved between the retracted and the extended state, i.e. when the respective tread is not locked in the retracted or the extended state by the locking elements. To this end, the at least one spring may be arranged in an edge section of the stepping area so as to reduce or compensate the tilting moment acting on the treads. The at least one spring may extend between next neighboring treads, respectively, so as to reduce the tilting moment between next neighboring treads down to the lower positioning area. The at least one spring may also extend directly from the respective extended tread down to the lower positioning area, so as to directly contact the lower positioning area. In case a plurality of springs is used, different spring constants may be used. In general, the spring constant may be adjusted according to the tilting moment to be compensated.

[0050] For example, the at least one spring may comprise or be a pneumatic spring.

[0051] According to another aspect of the invention, the staircase may comprise a cover lid configured to cover an upside of the staircase if all treads are in the retracted state. Using the cover lid, the staircase may be closed and safely stored when not in use.

[0052] According to yet another aspect of the invention, the staircase may comprise a ramp. Preferably, said ramp is configured to be mounted to an upmost tread of the staircase, such that the ramp connects the lower positioning surface and the tread surface of the upmost tread. The ramp may be advantageously used by a patient to practice walking on an oblique plane in addition to climbing stairs. A pitch angle of the oblique surface comprised by the ramp may be tuned by varying the number of extended treads. In another advantageous embodiment of the present invention, the ramp may comprise the cover lid.

[0053] In another aspect of the present invention, the staircase comprises a control unit configured to control the locking elements, and/or extension elements. The control unit may permit automated control over the staircase and particularly the extension, retraction, locking and unlocking of the treads, such that the staircase can be set up automatically, for example by the patient or medical personal.

[0054] Another aspect of the invention refers to a method for manual modular unlocking, extension or retraction and locking of a respective tread of the staircase, the method comprising the following steps:

i) While keeping all other treads locked, unlocking of the respective tread to be extended from the retracted to the extended state or to be retracted from the extended to the retracted state by the locking elements,

ii) by exerting a vertically upward or downward force on the respective tread, manual extension or retraction of the respective tread into the extended or the retracted state via the recesses and

iii) locking of the respective tread in the extended or the retracted state by the locking elements.

[0055] The term 'modular' refers to the unlocking, extension or retraction and locking of individual treads without the need to unlock, extend or retract and lock all extendable treads.

[0056] However, another aspect of the invention refers to a method for manual unlocking, extension or retraction and locking of all extendable treads of the staircase, the method comprising the following steps:

i) Unlocking of all extendable treads to be extended from the retracted to the extended state or to be retracted from the extended to the retracted state by the locking elements,

ii) by exerting a vertically upward or downward force on the upmost tread, manual extension or retraction of all extendable treads into the extended or the retracted state via the recesses and

iii) locking of all extendable treads in the extended or the retracted state by the locking elements.

[0057] This method particularly refers to embodiments wherein all extendable treads are connected to neighboring treads via the guidance units, (pivotable) support struts, levers or double levers, such that by exerting a vertically upward or downward force on the upmost tread, all lower treads will follow the respective vertical movement of the upmost tread, since all treads are mutually connected via the guidance units, levers and the like.

[0058] Another aspect of the invention refers to a method for automatic modular unlocking, extension or retraction and locking of the respective tread of the staircase, the method comprising the following steps executable by the control unit:

i) while keeping all other treads locked, prompting the locking elements to unlock the respective tread to be extended from the retracted to the extended state or to be retracted from the extended to the retracted state,

ii) by prompting the extension elements to exert a vertically upward or downward force on the respective tread, modular automatic extension or retraction of the respective tread into the extended or the retracted state via the extension elements, particularly the linear actuator, the chain actuator or the scissor lift actuator,

iii) automatic modular locking of the respective tread in the extended or the retracted state by the locking elements.

[0059] Another aspect of the invention refers to a method for automatic unlocking, extension or retraction and locking of all extendable treads of the staircase, the method comprising the following steps executable by the control unit:

i) unlocking of all extendable treads to be extended from the retracted to the extended state or to be retracted from the extended to the retracted state by the locking elements,

ii) by prompting the extension elements to exert a vertically upward or downward force on the upmost tread, automatic extension or retraction of all treads into the extended or the retracted state via the extension elements, particularly the linear actuator, the chain actuator or the scissor lift actuator and

iii) automatic locking of all extendable treads in the extended or the retracted state by the locking elements.

[0060] This method particularly refers to embodiments wherein all extendable treads are connected to neighboring treads via the guidance units, (pivotable) support struts, levers or double levers, such that by exerting a vertically upward or downward force on the upmost tread, all lower treads will follow the respective vertical movement of the upmost tread, since all treads are mutually connected via the guidance units, levers and the like.

[0061] Particularly, exemplary embodiments are described below in conjunction with the Figures. The Figures are appended to the claims and are accompanied by text explaining individual features of the shown embodiments and aspects of the present invention. Each individual feature shown in the Figures and/or mentioned in the text of the Figures may be incorporated (also in an isolated fashion) into a claim relating to the device according to the present invention.

Fig. 1

shows a schematic overview of an embodiment of the staircase according to the invention, wherein in the left figure, all treads in the retracted state and wherein in the right figure, all treads are in the extended state.

Figs. 2 a,b

show an embodiment of the staircase according to the invention, respectively.

Figs. 3 a-d

present various views of an embodiment showing guidance units comprised by the staircase as well as corresponding locking elements.

Figs. 4 a,b

show a side view of pivotable guidance units in the extended state and the retracted state as well as corresponding locking elements.

Figs. 5 a-c

show various side views of embodiments of a staircase according to the invention.

Figs. 6 a,b

show further embodiments of a staircase according to the invention.

Figs. 7 a-e

presents various extension elements used to extend or retract the treads of the staircase according to the invention.

Fig. 8

shows another embodiment of a staircase according to the invention, with a cover lid forming a ramp connecting the lower positioning area and the upper tread.

Fig. 9

shows another embodiment of a staircase according to the invention, additionally comprising rolls.

Figs. 10 a,b

show further embodiments of a staircase according to the invention, comprising at least one spring that may be used to reduce a tilting moment acting on the treads, particularly a tilting moment acting when the respective tread is moved between the retracted and the extended state,.

[0062] According to the invention, a modularly extendable staircase 100 comprises a plurality of extendable treads 20, each tread 20 comprising a tread surface 27, characterized in that each tread 20 is configured to be moved from a retracted state 11 to an extended state 12 such that when each tread 20 is arranged in its retracted state 11, the tread surfaces 27 extend in a common extension plane 28, and wherein when the respective tread 20 is arranged in an extended state 12 the tread surface 27 of the respective tread 20 extends parallel to and above a tread surface 27 of a neighboring tread 20.

[0063] Fig. 1 shows an embodiment for a staircase 100 according to the invention. According to this embodiment, the staircase 100 may form a cuboid when all treads 20 are in the retracted state 11. To this end, all extendable treads 20 may be arranged in a static, particularly non-extendable, lowermost tread. The cuboid may for example have a height H, a width W and a length L, wherein the height extends along or parallel to a vertical z-axis and the width and length extending along or parallel to a x- and a y- axis, respectively. The x- and the y-axis are within a horizontal plane perpendicular to the vertical z-axis, such that the x-, y- and z-axes span an orthogonal coordinate system. The terms vertical and horizontal refer to orientations relative to the coordinate system defined here.

[0064] The height H of the cuboid may correspond to a height H of a lowermost tread 23 and the dimensions of the width and length may define an area covered by the staircase 100, particularly covered by the lowermost tread 23.

[0065] The staircase 100 shown in Fig. 1 comprises cuboid treads 20 with each six pairwise opposing parallel walls, wherein four of the walls are oriented vertically and two horizontally, with reference to the coordinate system defined above. However, the invention is not limited to cuboid treads 20, such that the walls may for example also be rounded and opposing walls may be tilted at a finite angle relative to each other. Particularly, the walls may also comprise openings, wherein the openings may also cover a majority of a surface of an individual wall, as long as the remaining walls represent sufficient structure to maintain the stability of the staircase 100.

[0066] The extendable treads 20 of the staircase 100 constitute several advantages for a user, particularly for use in a hospital or a clinic. As shown in the embodiment of Fig. 1, the staircase 100 permits to arrange all extendable treads 20 in a volume comprised by the lowermost tread 23, making the staircase 100 very compact and easy to store. Particularly, the staircase 100 may be small enough to both be stored in the retracted state 11 and set up in the extended state 12 in a hospital room, i.e. close to the patient, such that the patient does not have to walk to the staircase 100. Second, according to the invention, individual extendable treads 20 may be extended modularly, i.e. independently of the other extendable treads 20, such that the number of extended treads 20 may be selected according to a training program of a patient. For example, a low number of treads 20 may be selected to start the training and a larger number of treads 20 may be selected for an advanced training.

[0067] While the example staircase 100 shown in Fig. 1 comprises five treads 20, wherein the last four treads 20 are modularly extendable, both the total number of treads 20 and the number of extendable treads are arbitrary. In some embodiments (not shown in Fig. 1) the staircase 100 may also comprise more than one, for example two, three or four treads 20 that are not extendable, followed by an arbitrary number of extendable treads 20. In case the staircase 100 comprises a set of non-extendable treads 20, the extendable and retractable treads 20 may be retractable into a volume defined by the set of not extendable and retractable treads 20.

[0068] As shown in Fig. 1, individual treads 20 may for example have an identical tread 20 height, particularly in the extended state 12. The extendable and retractable treads 20 may have the same tread 20 height as the static, non-extendable treads 20.

[0069] When in use, the lowermost tread 23 of the staircase 100 is preferably positioned on top of a lower positioning surface 1. As shown in the embodiment in Fig. 1, both the lower positioning surface 1 and the tread surfaces 27 may be arranged horizontally and parallel to each other, such that the patient does not need to balance or compensate any tilts between the lower positioning surface 1 and the tread surfaces 27. However, the lower positioning surface 1 and the tread surfaces 27 may also have a non-zero angle relative to each other. In this case, the tread surfaces 27 are preferably oriented such that they extend perpendicular to the vertical gravitational force, such that the patient does not need to balance.

[0070] In the embodiment of Fig. 1, the treads 20 of the staircase 100 are cuboids and shaped such that in the retracted state 11, all extendable treads 20 may be moved into a volume defined by the lowermost tread 23.

[0071] Figs. 2a and 2b show two further embodiments of the staircase 100 according to the invention.

[0072] As illustrated in Fig. 2a, the individual treads 20 may also be formed as a series of neighboring cuboids that have essentially the same geometry, wherein in the retracted state 11, their tread surfaces 27 extend in a common extension plane 28. In the extended state 12, the cuboids forming the treads 20 and in particular their tread surfaces 27 are moved vertically upwards such that the staircase 100 can be used as intended.

[0073] As shown in the embodiment of Fig. 2b, the staircase 100, particularly when in the extended state 12, may also be symmetric, such that the patient may climb up the staircase 100 on one side and down the staircase 100 on another side. The staircase 100 may also form a tread pyramid, wherein the tread surfaces 27 of higher treads 20 become gradually smaller.

[0074] Figs. 3a-d show an exemplary embodiment of the staircase 100 according to the invention with just two treads 20 and guidance units 30 arranged on the staircase 100, particularly on the treads 20 of the staircase. The guidance units 30 are preferably configured to be slidable between at least a first and a second position 31,32 so as to move the respective extendable tread 20 between the retracted and the extended state 11,12. Moreover, the guidance units 30 may be configured to receive locking elements configured to reversibly lock and unlock the guidance unit 30 in the first and second position 31,32.

[0075] Fig. 3a shows a top view (i.e. a view of the x-y-plane) of the exemplary embodiment with just two treads 20. The at least one respective guidance unit 30 may be arranged for example on two neighboring vertical walls of neighboring treads 20, slidably connecting the neighboring treads 20. The at least one guidance unit 30 may for example be mounted on an outside or an inside of the respective vertical wall.

[0076] As demonstrated also in the side view (here a view of the z-x-plane) of the present embodiment shown in Fig. 3b, the at least one guidance 30 unit may be arranged vertically (i.e. along the z-direction). In this representation, the first position 31 of the guidance unit 30 may be understood as a position along the vertical z-axis. If the guidance unit 30 is in its first position 31, as shown in Fig. 3b, the respective extendable tread 20 may be in the retracted state 12 with the tread surfaces 27 of the respective tread 20 and the neighboring tread 20 extending within a common extension plane 28. To ensure stability and a safe transfer between the retracted and the extended state 11,12, the staircase 100 may comprise a plurality of guidance units 30 arranged at multiple sites of two neighboring treads 20.

[0077] Now referring to Fig. 3c, if the guidance unit is moved into the second position 32, the respective extendable tread 20 may be in the extended state 12 such that the respective tread 20 may be in a position outside a volume defined by the (lower) neighboring tread 20 wherein the respective tread surface 27 is arranged above the tread surface 27 of the (lower) neighboring tread 20.

[0078] In order to lock a tread 20 in the retracted or the extended state 11,12, the staircase 100 may additionally comprise locking elements. As shown in Fig. 3d, the locking elements may for example comprise a pivoting magnet 81 with a locking pin 82. The pivoting magnet 81 may be configured to rotate around a respective axis C, particularly a horizontal axis within the x-y-plane, particularly parallel to the y axis, as an extendable tread 20 is moved between the retracted and the extended state 11,12. The rotation may cause the locking pin 82 to engage with the guidance unit 30 at least if the guidance unit 30 is in the first or second position 31,32, so as to fix the tread 20 in the retracted or extended state 11,12. The mechanism shown in Fig. 3d may likewise be applied as locking element for all other embodiments of the present invention if applicable.

[0079] Fig. 4a shows a side view of another embodiment of the present invention, wherein at least one guidance unit 30 may further be pivotable around an axis A within the x-y-plane, particularly parallel to the y-axis. Again, the present embodiment describes just two treads 20 as an example, even though the number of treads 20 may be arbitrary as stated above. In this embodiment, the guidance unit 30 may for example be arranged essentially horizontally in the retracted state 11. In order to transfer the respective extendable tread 20 from the retracted state 11 to the extended state 12, the guidance unit 30 may be pivoted around the axis A, such that the respective tread surface 27 of the respective extendable tread 20 is arranged vertically above the tread surface of the neighboring tread 20.

[0080] To lock the extendable tread 20 in the extended state 12, upon the rotation of the guidance unit 30 around the axis A, a locking element connected to the guidance unit 30 may slide from the first position 31 to the second position 32 along the guidance unit 30 so as to fix the extendable tread 20 in the retracted state 11 or the extended state 12. To this end, the locking element may for example comprise a locking pin 82 that engages via through holes 83 of a guidance unit 30 with a vertical wall of the respective tread 20. The locking pin 82 may be inserted for manually, or, for example, by a lifting magnet 80.

[0081] Fig. 4b shows a schematic cross-section of the lifting magnet 80 slidably arranged on the guidance unit 30, wherein the guidance unit 30 comprises at least two through holes 83 that may be used to engage the locking pin 82 via the respective through hole 83 so as to fix the guidance unit 30 in the first or second position 31,32. The first or second position 31,32 may correspond to the retracted and the extended state 11,12 of the respective extendable tread 20. The mechanism shown in Fig. 4b may likewise be applied to pivotable guidance units 30 and be used as a locking element for all other embodiments of the present invention if applicable.

[0082] Figs. 5a-c show side views of further embodiments of a staircase 100 of the present invention with just two treads 20 as an example, even though the number of treads 20 may be arbitrary as stated above.

[0083] As shown in Fig. 5a, the staircase 100 may comprise support struts 50 that may be used to support and lock a tread 20 in the extended state 12. Preferably, the support struts 50 may be pivotable support struts 50 around at least one respective axis B parallel to the horizontal x-y plane, particularly parallel to the y-axis, so as to facilitate a transition of a respective tread 20 between the retracted state 11 and the extended state 12. The pivotable support struts 50 may for example be mounted on at least one vertical wall of the respective tread 20. The pivotable support struts 50 may particularly be mounted on the outside and/or the inside of the respective vertical wall. Additionally, the staircase 100 may comprise support blocks 60 that may be used to support the pivotable support struts 50 in the extended state 12. To this end, a pivotable support strut 50 of the respective extendable tread 20 may be oriented essentially vertically above a corresponding support block 60 of the (lower) neighboring tread, as shown in Fig. 5a. The support blocks 60 may for example be mounted on at least one vertical wall of the respective tread 20.

[0084] Fig. 5b shows another embodiment of the present invention, wherein the pivotable support struts 50 connect neighboring treads 20 such that the support struts 50 are pivotable around a first pivot axis B1 comprised by a first tread 20 and around a second pivot axis B2 comprised by a second tread 20 being a neighboring tread 20 of the first tread 20. Preferably, the first and the second pivot axis B1,B2 are parallel to each other and parallel to the horizontal x-y-plane, particularly parallel to the y-axis. In this embodiment, the second tread 20 may be pivoted above the first tread 20 and safely positioned beyond a dead center 53 defined by the axis B1 such that the second tread 20 is supported by the tread surface 27 of the first tread 20 in the extended state 12.

[0085] Fig. 5c shows yet another embodiment of the present invention, wherein the pivotable support struts 50 are formed by at least one of the vertical walls of the respective extendable tread 20. In this embodiment, the vertical wall may be oriented essentially vertically in the extended state 12 while in the retracted state 11, it may be oriented essentially horizontally or at an arbitrary angle relative to the horizontal x-y-plane, as shown in Fig. 5c. Similar to the embodiment shown in Fig. 5a, the at least one vertical wall forming the pivotable support strut 50 may for example be supported by one or more corresponding support block 60.

[0086] Figs. 6a,b show side views of further embodiments of a staircase 100 of the present invention with just three treads 20 as an example, even though the number of treads 20 may be arbitrary as stated above.

[0087] In the embodiment shown in Fig. 6a, the respective pivotable support struts 50 of a respective extendable tread 20 may pivot around a respective pivot axis C1,C2. In this embodiment, the pivotable support struts 50 may be arranged vertically and supported by the lower positioning surface 1 in the extended state 12. In this particular embodiment, in the extended state 12, the pivotable support struts 50 of every tread 20 preferably extend from its respective pivot axis C1,C2 down to the lower positioning surface 1, so as to support the extended treads 20 directly on the lower positioning surface 1. While a vertical orientation of the pivotable support struts 50 in this embodiment may be advantageous in the extended state 12 so as to minimize or avoid a tilt caused by a patient or user stepping on the tread surface 27 of an extended tread, the orientation of the pivotable support struts 50 in the retracted state 11 may deviate from a horizontal orientation depending on the constructive details of the staircase 100, as shown in Fig. 6a.

[0088] Fig. 6b shows another embodiment of the present invention, wherein the pivotable support struts 50 may connect neighboring treads 20 such that the pivotable support struts 50 are pivotable around the first and second pivot axis B1,B2 as well as a third pivot axis B3 parallel to the first and second pivot axis B1, B2, forming double levers 52 configured to reversibly pivot the respective extendable tread 20 between the extended and retracted state 12,11.

[0089] Figs. 7a-d present various embodiments of the present invention, showing various extension elements configured to extend or retract the treads 20 into the extended and the retracted state 12,11.

[0090] Particularly, Fig. 7a refers to an embodiment of the present invention wherein the staircase 100 comprises recesses 70. The recesses 70 may be used for manual extension and retraction of individual or all treads 20 by a user. For instance, individual or all extendable treads 20 may be extended by pulling the treads 20 vertically up along the z-axis perpendicular to the x-y-plane. The treads 20 may be supported or locked for example using the pivotable support struts 50 and optionally in combination with the support blocks 60 and/or the guidance units 30, as explained in the embodiments above. As shown in Fig. 7a, the recesses 70 may for example be arranged on the respective tread surfaces 27 of every extendable tread 20. After modularly locking or unlocking individual treads by the locking elements, individual extendable treads 20 may be manually extended or retracted via the recesses 70. After locking or unlocking all treads 20 by the locking elements, all extendable treads 20 may be manually extended or retracted via the recesses 70.

[0091] Fig. 7b refers to an embodiment of the present invention wherein the staircase 100 comprises a chain 71. The chain 71 may be arranged essentially horizontally in the retracted state. After modularly locking or unlocking individual extendable treads 20 by the locking elements, individual treads 20 may be extended or retracted via the chain 71. After locking or unlocking all treads 20 by the locking elements, all treads 20 may be extended or retracted via the chain 71. The chain 71 may be operated manually, or by an optional chain actuator.

[0092] Fig. 7c refers to an embodiment of the present invention wherein the staircase 100 comprises a linear actuator 72. The linear actuator 72 may be connected to members connecting individual treads 20. As shown in Fig. 7c, the linear actuator 72 may be arranged horizontally and configured to extend or retract the treads 20 by moving along the horizontal direction. After modularly locking or unlocking individual extendable treads 20 by the locking elements, individual extendable treads 20 may be extended or retracted via the linear actuator 72. After locking or unlocking all extendable treads 20 by the locking elements, all extendable treads 20 may be extended or retracted via the linear actuator 72.

[0093] Fig. 7d refers to an embodiment of the present invention wherein the staircase 100 comprises a linear actuator 72 that is further pivotable around an axis D wherein it is connected to the lowermost and upmost tread 23,22 of the staircase 100. After modularly locking or unlocking individual treads by the locking elements, individual treads may be extended or retracted via the pivotable linear actuator 72. After locking or unlocking all treads 20 by the locking elements, all treads 20 may be extended or retracted via the pivotable linear actuator 72.

[0094] Fig. 7e refers to an embodiment of the present invention wherein the staircase 100 comprises a scissor lift 74. The scissor lift 74 may comprise pivotable X-shaped members connecting the individual treads 20. As shown here, the scissor lift may also only connect for example every second tread 20. The scissor lift 74 may optionally be controlled by a scissor lift actuator. After modularly locking or unlocking individual extendable treads 20 by the locking elements, individual extendable treads 20 may be extended or retracted via the scissor lift 74. After locking or unlocking all extendable treads 20 by the locking elements, all extendable treads 20 may be extended or retracted via the scissor lift 74.

[0095] Additionally, the staircase 100 may comprise a control unit (not shown) configured to control the locking elements, and/or the extension elements shown in Figs. 7a-e. The control unit may permit automated control over the staircase 100 and particularly the extension, retraction, locking and unlocking of the treads 20, such that the staircase 100 can be set up automatically, for example by the patient or medical personal.

[0096] Fig. 8 shows another embodiment of the present invention wherein the staircase 100 comprises a cover lid 91. The cover lid 91 may be arranged above the common extension plane 28 to cover and close the staircase 100 if all treads 20 are in the retracted state 11. Using the cover lid 91, the staircase 100 may be closed and safely stored when not in use. When in use, and particularly when in use in the extended state 12, the staircase 100 may comprise a ramp 92 configured to be mounted to the upmost tread 22. As such, the ramp 92 may connect the lower positioning surface 1 and the tread surface 27 of the upmost tread 22. The ramp 92 may be used by a patient to practice walking on an oblique plane in addition to climbing stairs. A pitch angle of the oblique plane may be tuned by varying the number of extended treads 20. In another advantageous embodiment of the present invention, the ramp 92 may comprise the cover lid 91.

[0097] Fig. 9 shows another embodiment of the present invention wherein the staircase 100 comprises rolls 93. The rolls 93 may be mounted for example on the front or backside of the staircase 100, i.e. in the area of the two ends along the length of the staircase 100 extending along the y-axis and be used to pull or roll the staircase 100 over the lower positioning surface 1, so as to facilitate the transport of the staircase 100, particularly in the retracted state 11.

[0098] Figs. 10a and 10b show embodiments of the present invention wherein the staircase 100 comprises at least one spring 90. The at least one spring 90 may be used to reduce the tilting moment acting on the treads 20, particularly a tilting moment acting when the respective tread 20 is moved between the retracted and the extended state 11,12, i.e. when the respective tread 20 is not locked in the retracted or the extended state 11,12. Preferably, as shown in Figs. 10a and 10b, the at least one spring 90 may be arranged in an at least one edge section of the tread surface 27 so as to reduce the tilting moment. The at least one spring 90 may extend essentially between next neighboring treads 20, so as to reduce the tilting moment between next neighboring treads 20 by supporting the respective spring 90 on the next lower tread surface 27 respectively for every extendable tread 20 in a cascade-manner down to the lower positioning surface 1, as shown in Fig. 10a.

[0099] As shown in Fig. 10b, the at least one spring 90 may also be pivotable around a respective axis and connect next neighboring treads 20, so as to reduce the tilting moment.

[0100] In case a plurality of springs 90 is used, different spring constants may be used. In general, the spring constant may be adjusted according to the tilting moment to be compensated. For example, the at least one spring 90 may comprise or be a pneumatic spring.

[0101] In the following, further aspects of the present invention and embodiments thereof are stated as items. These items may also be formulated as claims of the present invention/application at hand. The reference numerals in parentheses also refer to the appended Figures.

[0102] Item 1: A modularly extendable staircase (100) comprising a plurality of extendable treads (20), each tread (20) comprising a tread surface (27), characterized in that each tread (20) is configured to be moved from a retracted state (11) to an extended state (12) such that when each tread (20) is arranged in its retracted state (11), the tread surfaces (27) extend in a common extension plane (28), and wherein when the respective tread (20) is arranged in an extended state (12) the tread surface (27) of the respective tread (20) extends parallel to and above a tread surface (27) of a neighboring tread (20).

[0103] Item 2: The staircase (100) according to item 1, wherein when all treads (20) are in the retracted state (11), the staircase (100) forms a cuboid, particularly a cuboid extending by a height H along a vertical z-axis, a width W and a length L extending along a horizontal x- and y-axis, respectively, wherein the x-, y- and z-axes define an orthogonal coordinate system.

[0104] Item 3: The staircase (100) according to item 2, wherein an aspect ratio R = W/L is within 0.2 and 0.8 and wherein the height H is within 5 cm and 30 cm.

[0105] Item 4: The staircase (100) according to one of the preceding items, comprising at least one guidance unit (30) arranged at the treads (20) and configured to be slidable between and fixable at at least a first and a second position (31,32), wherein the first and second position (31,32) correspond to the retracted and the extended state (11,12) of a respective extendable tread (20), respectively.

[0106] Item 5: The staircase (100) according to item 4, characterized in that the at least one guidance unit (30) is connecting the respective tread (20) with its neighboring treads (18,19).

[0107] Item 6: The staircase (100) according to item 5, characterized in that the at least one guidance unit (30) is arranged vertically, wherein in the first position (31) the respective tread (20) is in the retracted state (11) and wherein in the second position (32) the respective tread (20) is in the extended state (12), the second position (32) being above the first position (31).

[0108] Item 7: The staircase (100) according to one of the items 4 to 6, characterized in that the at least one guidance unit (30) is pivotable around an axis (A) extending along a horizontal axis, particularly parallel to the x-axis.

[0109] Item 8: The staircase (100) according to item 7, wherein in the first position (31), the at least one guidance unit (30) is arranged horizontally with the respective tread (20) being in the retracted state (11) and wherein in the second position (32), the at least one guidance unit (30) is pivoted around the axis (A) such that the respective tread (20) is in the extended state (12).

[0110] Item 9: The staircase (100) according to one of the preceding items, characterized in that the treads (20) comprise support struts (50).

[0111] Item 10: The staircase (100) according to item 9, wherein respective support struts (50) are pivotable around a respective axis (B) extending along a horizontal axis, particularly parallel to the x-axis, forming pivotable support struts (50).

[0112] Item 11: The staircase (100) according to item 9, wherein the support struts (50) are pivotable support struts (50) connecting neighboring treads (20) such that the pivotable support struts (50) are pivotable around a first pivot axis (B1) extending along a horizontal axis through the respective tread (20), particularly parallel to the x-axis, and around a second pivot axis (B2) through the neighboring tread (20), the pivot axes (B1,B2) being parallel and offset from each other.

[0113] Item 12: The staircase (100) according to item 11, wherein the pivotable support struts (50) connecting the neighboring treads (20) are further pivotable around a third pivot axis (B3) parallel to the first and second pivot axes (B1, B2), forming double levers (52) configured to pivot the respective tread (20) between the extended and retracted state (12,11).

[0114] Item 13: The staircase (100) according to one of the preceding items, characterized the treads (20) comprise support blocks (60).

[0115] Item 14: The staircase (100) according to one of the preceding items, comprising extension elements configured to extend the respective tread (20) from the retracted state (11) to the extended state (12) via the guidance units (30) and/or the support struts (50) as well as to retract the respective tread (20) from the extended state (12) to the retracted state (11) via the guidance units (30) and/or the support struts (50).

[0116] Item 15: The staircase (100) according to item 14, wherein the extension elements comprise recesses (70) arranged on the respective tread (20) for manual extension of the respective tread (20) from the retracted state (11) to the extended state (12) as well as for manual retraction of the respective tread (20) from the extended state (12) to the retracted state (11).

[0117] Item 16: The staircase (100) according to item 14, wherein the extension elements comprise a chain (71) controlled by a chain actuator configured to automatically extend the respective tread (20) from the retracted state (11) to the extended state (12) as well as to automatically retract the respective tread (20) from the extended state (12) to the retracted state (11).

[0118] Item 17: The staircase (100) according to item 14, wherein the extension elements comprise a linear actuator (72) configured to automatically extend the respective tread (20) from the retracted state (11) to the extended state (12) as well as to automatically retract the respective tread (20) from the extended state (12) to the retracted state (11).

[0119] Item 18: The staircase (100) according to item 17, wherein the linear actuator (72) is further configured to pivot around a respective axis (D) extending along a horizontal axis, particularly parallel to the x-axis.

[0120] Item 19: The staircase (100) according to item 17 or 18, wherein the linear actuator (72) is coupled to a lever (73) configured to automatically extend the respective tread (20) from the retracted state (11) to the extended state (12) as well as to automatically retract the respective tread (20) from the extended state (12) to the retracted state (11).

[0121] Item 20: The staircase (100) according to item 14, characterized in that the extension elements comprise a scissor lift (74) controlled by a scissor lift actuator configured to automatically extend the respective tread (20) from the retracted state (11) to the extended state (12) as well as to automatically retract the respective tread (20) from the extended state (12) to the retracted state (11).

[0122] Item 21: The staircase (100) according to one of the items 16 to 20, comprising an electrical connection configured to be connected to an external power supply or at least one battery for powering the chain actuator, linear actuator (72) or scissor lift actuator.

[0123] Item 22: The staircase (100) according to item 21, wherein the batteries are mounted inside a volume defined by the staircase (100).

[0124] Item 23: The staircase (100) according to item 21 or 22, wherein the batteries are configured to be automatically recharged via an external power supply.

[0125] Item 24: The staircase (100) according to one of the preceding items, comprising locking elements for locking and unlocking the respective extendable tread (20) in the extended or the retracted state (12,11).

[0126] Item 25: The staircase (100) according to item 24, characterized in that the locking elements comprise the pivotable support struts (50), wherein in the extended state (12), the pivotable support struts (50) of the respective tread (20) are arranged vertically and supported by the support blocks (60) of the neighboring tread (20) and wherein in the retracted state (11), the pivotable support struts (50) of the respective tread (20) are arranged horizontally.

[0127] Item 26: The staircase (100) according to item 24, characterized in that the locking elements comprise the pivotable support struts (50), wherein in the extended state (12), the respective tread (20) is pivoted into a position beyond a dead center (53) of the pivotable support struts (50) such that the respective tread (20) is supported by the tread surface (27) of the neighboring tread (20) and wherein in the retracted state (11), the pivotable support struts (50) are arranged horizontally.

[0128] Item 27: The staircase (100) according to item 24, characterized in that the locking elements comprise the double lever (52), the double lever (52) being configured to pivot the respective tread (20) between the extended state (12) and the retracted state (11).

[0129] Item 28: The staircase (100) according to item 24, characterized in that the pivotable support struts (50) comprise at least one wall defining the respective tread (20).

[0130] Item 29: The staircase (100) according to item 24, characterized in that the locking elements comprise the pivotable support struts (50), wherein in the extended state (12), the pivotable support struts (50) are arranged vertically such that when the staircase (100) is positioned on a lower positioning surface (1), the pivotable support struts (50) are supported by the lower positioning surface (1).

[0131] Item 30: The staircase (100) according to item 24, characterized in that the locking elements comprise at least one locking pin (82).

[0132] Item 31: The staircase (100) according to item 24, characterized in that the locking elements comprise at least one lifting magnet (80) arranged on the treads (20), wherein the at least one lifting magnet (80) is configured to engage and extract the locking pin (82) so as to lock and unlock the respective tread (20) in the extended or the retracted state (12,11).

[0133] Item 32: The staircase (100) according to item 24, characterized in that the locking elements comprise at least one pivoting magnet (81), the pivoting magnet (81) being configured to pivot the locking pin (82) around a respective axis (C) so as to lock and unlock the respective tread (20) in the extended or the retracted state (12,11).

[0134] Item 33: The staircase (100) according to one the items 30 to 32, wherein the locking pin (82) engages in the at least one guidance unit (30), particularly in a through hole (83) of the at least one guidance unit (30) to lock the respective tread (20) in the extended state (12).

[0135] Item 34: The staircase (100) according to one of the preceding items, comprising at least one force sensor configured to determine a force exerted by a patient stepping on the respective tread surface (27) of the respective tread (20).

[0136] Item 35: The staircase (100) according to one of the preceding items, comprising at least one spring (90) configured to reduce a tilting moment acting on the treads (20), particularly a tilting moment acting when the respective tread (20) is moved between the retracted and the extended state (11,12).

[0137] Item 36: The staircase (100) according to item 35, comprising at least one pneumatic spring.

[0138] Item 37: The staircase (100) according to one of the preceding items, comprising a cover lid (91) configured to cover an upside of the staircase if all treads (20) are in the retracted state (11).

[0139] Item 38: The staircase (100) according to one of the preceding items, comprising a ramp (92) configured to be mounted to an upmost tread (22), the ramp (92) connecting the lower positioning surface (1) and the tread surface (27) of the upmost tread (22).

[0140] Item 39: The staircase (100) according to item 38, characterized in that the ramp (92) comprises the cover lid (91).

[0141] Item 40: The staircase (100) according to one of the preceding items, comprising rolls (93) configured to roll the staircase (100).

[0142] Item 41: The staircase (100) according to one of the preceding items, comprising a control unit configured to control the locking elements and/or the extension elements.

[0143] Item 42: A method for manual modular unlocking, extension or retraction and locking of the respective tread (20) of the staircase (100) according to one of the preceding items, the method comprising the following steps:

i) While keeping all other treads (20) locked, unlocking of the respective tread (20) to be extended from the retracted to the extended state (11,12) or to be retracted from the extended to the retracted state (12,11) by the locking elements,

ii) by exerting a vertically upward or downward force on the respective tread (20), manual extension or retraction of the respective tread (20) into the extended or the retracted state (12,11) via the recesses (70) and

iii) locking of the respective tread (20) in the extended or the retracted state (12,11) by the locking elements.

[0144] Item 43: A method for unlocking, extension or retraction and locking of all extendable treads (20) of the staircase (100) according to one of the items 1 to 41, comprising the following steps:

i) Unlocking of all extendable treads (20) to be extended from the retracted to the extended state (11,12) or to be retracted from the extended to the retracted state (12,11) by the locking elements,

ii) by exerting a vertically upward or downward force on the upmost tread (22), manual extension or retraction of all extendable treads (20) into the extended or the retracted state (12,11) via the recesses (70) and

iii) locking of all extendable treads (20) in the extended or the retracted state (12,11) by the locking elements.

[0145] Item 44: A method for automatic modular unlocking, extension or retraction and locking of the respective tread (20) of the staircase (100) according to one of the items 1 to 41, the method comprising the following steps executable by the control unit:

i) while keeping all other treads (20) locked, prompting the locking elements to unlock the respective tread (20) to be extended from the retracted to the extended state (11,12) or to be retracted from the extended to the retracted state (12,11),

ii) by prompting the extension elements to exert a vertically upward or downward force on the respective tread (20), modular automatic extension or retraction of the respective tread (20) into the extended or the retracted state (12,11) via the extension elements, particularly the linear actuator (72), the chain actuator or the scissor lift actuator and

iii) automatic modular locking of the respective tread (20) in the extended or the retracted state (12,11) by the locking elements.

[0146] Item 45: A method for automatic unlocking, extension or retraction and locking of all extendable treads (20) of the staircase (100) according to one of the items 1 to 41, the method comprising the following steps executable by the control unit:

i) unlocking of all extendable treads (20) to be extended from the retracted to the extended state (11,12) or to be retracted from the extended to the retracted state (12,11) by the locking elements,

ii) by prompting the extension elements to exert a vertically upward or downward force on the upmost tread (22), automatic extension or retraction of all treads (20) into the extended or the retracted state (12,11) via the extension elements, particularly the linear actuator (72), the chain actuator or the scissor lift actuator and

iii) automatic locking of all extendable treads (20) in the extended or the retracted state (12,11) by the locking elements.

Claims

1. A modularly extendable staircase (100) comprising a plurality of extendable treads (20), each tread (20) comprising a tread surface (27), characterized in that each tread (20) is configured to be moved from a retracted state (11) to an extended state (12) such that when each tread (20) is arranged in its retracted state (11), the tread surfaces (27) extend in a common extension plane (28), and wherein when the respective tread (20) is arranged in an extended state (12) the tread surface (27) of the respective tread (20) extends parallel to and above a tread surface (27) of a neighboring tread (20).

2. The staircase (100) according to claim 1, wherein when all treads (20) are in the retracted state (11), the staircase (100) forms a cuboid, particularly a cuboid extending by a height H along a vertical z-axis, a width W and a length L extending along a horizontal x- and y-axis, respectively, wherein the x-, y- and z-axes define an orthogonal coordinate system.

3. The staircase (100) according to claim 2, wherein an aspect ratio R = W/L is within 0.2 and 0.8 and wherein the height H is within 5 cm and 30 cm.

4. The staircase (100) according to one of the preceding claims, comprising at least one guidance unit (30) arranged at the treads (20) and configured to be slidable between and fixable at at least a first and a second position (31,32), wherein the first and second position (31,32) correspond to the retracted and the extended state (11,12) of a respective extendable tread (20), respectively.

5. The staircase (100) according to claim 4, characterized in that the at least one guidance unit (30) is connecting the respective tread (20) with its neighboring treads (18,19).

6. The staircase (100) according to claim 5, characterized in that the at least one guidance unit (30) is arranged vertically, wherein in the first position (31) the respective tread (20) is in the retracted state (11) and wherein in the second position (32) the respective tread (20) is in the extended state (12), the second position (32) being above the first position (31).

7. The staircase (100) according to one of the claims 4 to 6, characterized in that the at least one guidance unit (30) is pivotable around an axis (A) extending along a horizontal axis, particularly parallel to the x-axis.

8. The staircase (100) according to claim 7, wherein in the first position (31), the at least one guidance unit (30) is arranged horizontally with the respective tread (20) being in the retracted state (11) and wherein in the second position (32), the at least one guidance unit (30) is pivoted around the axis (A) such that the respective tread (20) is in the extended state (12).

9. The staircase (100) according to one of the preceding claims, characterized in that the treads (20) comprise support struts (50).

10. The staircase (100) according to claim 9, wherein respective support struts (50) are pivotable around a respective axis (B) extending along a horizontal axis, particularly parallel to the x-axis, forming pivotable support struts (50).

11. The staircase (100) according to claim 9, wherein the support struts (50) are pivotable support struts (50) connecting neighboring treads (20) such that the pivotable support struts (50) are pivotable around a first pivot axis (B1) extending along a horizontal axis through the respective tread (20), particularly parallel to the x-axis, and around a second pivot axis (B2) through the neighboring tread (20), the pivot axes (B1,B2) being parallel and offset from each other.

12. The staircase (100) according to claim 11, wherein the pivotable support struts (50) connecting the neighboring treads (20) are further pivotable around a third pivot axis (B3) parallel to the first and second pivot axes (B1, B2), forming double levers (52) configured to pivot the respective tread (20) between the extended and retracted state (12,11).

13. The staircase (100) according to one of the preceding claims, characterized the treads (20) comprise support blocks (60).

14. The staircase (100) according to one of the preceding claims, comprising extension elements configured to extend the respective tread (20) from the retracted state (11) to the extended state (12) via the guidance units (30) and/or the support struts (50) as well as to retract the respective tread (20) from the extended state (12) to the retracted state (11) via the guidance units (30) and/or the support struts (50).

15. The staircase (100) according to claim 14, wherein the extension elements comprise recesses (70) arranged on the respective tread (20) for manual extension of the respective tread (20) from the retracted state (11) to the extended state (12) as well as for manual retraction of the respective tread (20) from the extended state (12) to the retracted state (11).

Drawing