Wheelchair, in particular medical wheelchair

Abstract

The invention relates to a wheelchair comprising a seat (5), a first wheel (1) wherein the wheelchair further comprises: a second wheel (2) which is higher than the first wheel (1), and wherein the first wheel (1) is retractable so as to be higher than the second wheel (2) when retracted.

Description

Technical Field

[0001] The present invention relates to the technical field of wheelchairs, and more preferably, to the technical field of medical wheelchairs. Background Art

[0002] According to a first prior art, there is a wheelchair with a seat on which a person can sit, and the seat is supported by rolling wheels so that the seated person can drive on the floor. The seated person may be, for example, a permanently disabled person, a temporarily disabled person, or an immobile patient in the hospital. When the ground is flat, moving forward is relatively easy. However, when there are some obstacles and / or some undulations, such as steps to climb, this may become difficult for the seated person. He or she not only often needs the help of another pedestrian, but this help may even require a lot of physical effort from the helping pedestrian, especially when the steps to climb may not be very high, but the seated person is heavy.

[0003] Of course, a system can be implemented that will help the seated person climb the steps with or without the help of a pedestrian while remaining quietly seated in the wheelchair. However, although this system may be efficient, it will most likely be complex and cumbersome.

[0004] According to a second prior art, for example, as disclosed in the prior art US20160346144, a patient chair with adjustable height for radiological imaging is known. However, when there are steps to climb and the person is already seated in the wheelchair, this second prior art is not very useful.

[0005] Considering the preferred application of a medical wheelchair, a radiology device may have an electric platform that allows a (normal, non-disabled) patient to be positioned at several different heights in a stationary position, preferably at two different heights:

[0006] - A first examination height, for example, at 10 cm from the floor, which allows the patient to climb onto the platform but keeps the feet outside the X-ray field,

[0007] - A second examination height, for example, 43 cm from the floor, which allows the X-ray tube to be located under the patient's feet and allows the patient to perform a full-body scan (from the soles of his feet to the top of his head).

[0008] This platform often cannot be removed from the system, meaning that the actual steps to climb have a significant height of, for example, at least 10 cm.

[0009] For immobile patients, the patient needs to be imaged while sitting in a radiolucent wheelchair. Transferring the patient from his personal wheelchair to the radiolucent wheelchair can be difficult, depending on his weight and disability. It is preferably done in an open environment where all sides of both chairs can be accessed. Thus, it is better to perform the transfer outside the acquisition area of the radiology equipment.

[0010] Subsequently, the radiolucent wheelchair with the patient sitting therein must be placed in the acquisition area of the radiology system on the platform to perform the patient imaging acquisition examination, and the radiology system is preferably an X-ray system.

[0011] Thus, the wheelchair should enable the patient sitting on it to safely climb this 10-cm step without the assisting operator having to exert excessive force. It should also allow climbing down from the platform after the examination under the same comfortable conditions. Summary of the Invention

[0012] The object of the present invention is to at least partially alleviate the above-mentioned drawbacks.

[0013] More specifically, the present invention seeks a system that is rather simple and easy, which is efficient by allowing the person sitting to remain quietly on the wheelchair, while the assisting pedestrian will need little physical strength to help the wheelchair carrying the sitting person successfully climb the steps. The preferred scenario the present invention relates to corresponds to the case where the height of the steps to be climbed is known in advance and remains constant, such as the predetermined step height within the radiology equipment.

[0014] Therefore, the present invention proposes to have a second wheel at the correct height, i.e., at the height of the steps to be climbed, while the first wheel on the ground is retractable, such that when the second wheel takes over from the first wheel by resting on the steps to be climbed, the first wheel retracts so that the wheelchair rolls on the steps and the first wheel no longer rolls on the ground, thereby allowing the wheelchair carrying the sitting person to smoothly reach the higher steps to be climbed from the ground, while keeping the seat and the person sitting thereon at approximately the same height during the transfer from the first lower height on the ground to the second higher height of the steps to be climbed.

[0015] This first object of the present invention is achieved by a wheelchair comprising a seat, a first wheel, wherein the wheelchair further comprises a second wheel, the second wheel being higher than the first wheel, and wherein: the first wheel is retractable so as to be higher than the second wheel when retracted.

[0016] Relative to the ground on which the wheelchair is located and on which the wheelchair can roll, the second wheel is higher than the first wheel. The lowermost part of the periphery of the second wheel that can roll on the ground is higher than the lowermost part of the periphery of the first wheel, and the first wheel will thus roll on the ground. Preferably, the axis of rotation of the second wheel is also higher than the axis of rotation of the first wheel.

[0017] The first set of wheels is retractable so that when retracted, it is higher than the second set of wheels relative to the ground on which the wheelchair is located and on which the wheelchair can roll. The lowermost part of the periphery of the first set of wheels that can roll on the ground is higher than the lowermost part of the periphery of the second set of wheels, and the second set of wheels will thus roll on the ground. Preferably, the axis of rotation of the first set of wheels is also higher than the axis of rotation of the second set of wheels.

[0018] This first object of the invention is also achieved by a radiology system, wherein the radiology system comprises a wheelchair according to any one of the preceding claims, and a radiology device, the radiology device comprising: a gantry, which is enclosed within a cover; a patient table; two radiation sources, which have imaging directions orthogonal to each other, the two radiation sources sliding vertically to perform a vertical scan of a patient standing on the table, the top view of the gantry cover being L-shaped, each of the two radiation sources being located outside the L-shaped gantry cover and inside the angular sector of the L, and being enclosed within the cover, and the cover sliding vertically together with the radiation source it encloses.

[0019] This radiology system and this radiology device are preferably the system and device claimed and described in patent application WO 2021090042, which patent application is hereby incorporated herein by reference.

[0020] When the radiology device is used by a disabled patient or a non-ambulatory patient, the table in this radiology device is a step that the disabled patient or the non-ambulatory patient sitting in the wheelchair has to climb. If the disabled patient or the non-ambulatory patient is sitting in a wheelchair according to an embodiment of the invention, he will be able to perform a medical examination inside the radiology device with maximum comfort, while if he is sitting in a prior art wheelchair, he will feel discomfort during the placement before performing this medical examination. Therefore, this makes the wheelchair according to the invention a very valuable asset when used inside a radiology device having a patient table or a patient lifting platform.

[0021] If not associated with a wheelchair according to the invention, some hospitals may not even be willing to purchase a radiology device and incorporate it into a radiology system that combines a wheelchair according to the invention with a radiology device that presents a patient table or a lifting platform at a height different from the rest of the floor. Some hospitals believe that a radiology system that is fully suitable for ambulatory patients but will cause a lot of discomfort to disabled or non-ambulatory patients is generally inadequate.

[0022] According to an embodiment of the invention, it is intended to provide a radiolucent chair for adults and children, the chair having means for allowing a patient sitting on the chair to be placed on a platform significantly higher than the floor, for example on a 10 cm high platform.

[0023] According to an embodiment of the present invention, the wheelchair is a device that allows for the acquisition of frontal and lateral images of immobile patients in a functional sitting position. Immobile patients are those who must be assisted by another person to walk, including wheelchair users and patients who have difficulty remaining stationary when standing without an assistive device. Being able to image these patients will allow them to benefit from low-dose radiological examinations, 3D modeling, and patient-specific parameters, as well as (if necessary) spinal modules for preoperative spinal surgery planning, even when the corresponding radiological equipment presents a patient platform above the ground. The patients imaged in this wheelchair will have the opportunity to benefit from the complete care path provided by radiological equipment with a patient platform above the ground.

[0024] Preferred embodiments include one or more of the following features, which may be combined singly or together with this first object part of the present invention, either partially or fully.

[0025] Preferably, the wheelchair further includes: two first front wheels associated with two second front wheels, and two first rear wheels associated with two second rear wheels.

[0026] Therefore, a smooth transfer from a first lower height at ground level to a second higher height at step level (the second higher height being higher than the first lower height) can be performed step by step, that is, first the front part of the wheelchair and then the rear part of the wheelchair, or first the rear part of the wheelchair and then the front part of the wheelchair.

[0027] Preferably, the wheelchair further includes a first front locking mechanism that secures the position of the first front wheels when not retracted, and a first rear locking mechanism that secures the position of the first rear wheels when not retracted.

[0028] Preferably, there is at least a first locking mechanism that secures the position of at least part of the first wheels when not retracted.

[0029] Therefore, when driving the wheelchair at a given level at the same height, the risk of the first wheels retracting when not desired is reduced or eliminated, such as when contacting small obstacles or when encountering small undulating changes, thereby making the wheelchair unbalanced, which is quite uncomfortable for the seated person and also poses a risk of the seated person falling to the ground, which is quite dangerous.

[0030] Preferably, the wheelchair further includes: a second front locking mechanism that secures the locking of the first front locking mechanism, and a second rear locking mechanism that secures the locking of the first rear locking mechanism.

[0031] Preferably, there is at least a second locking mechanism that secures the locking of the first locking mechanism or at least one of the first locking mechanisms.

[0032] Thus, due to this dual - stage locking system, the locking of the retractable first wheels can no longer be inadvertently activated under unwanted activation circumstances, even with the help of a distracted pedestrian.

[0033] Preferably, the wheelchair further includes a third - front wheel associated with the two first front wheels and the two second front wheels, and a third - rear wheel associated with the two first rear wheels and the two second rear wheels. The unlocking of the second front - locking mechanism is automatically and mechanically driven by a pressure on the third - front wheel being higher than a given threshold, where the given threshold corresponds to the wheelchair being loaded on the second front wheels rather than the first front wheels. This pressure higher than the given threshold automatically and mechanically triggers a lock visual indicator to show that the second front - locking mechanism is unlocked. The unlocking of the second rear - locking mechanism is automatically and mechanically driven by a pressure on the third - rear wheel being higher than a given threshold, where the given threshold corresponds to the wheelchair being loaded on the second rear wheels rather than the first rear wheels. This pressure higher than the given threshold automatically and mechanically triggers a lock visual indicator to show that the second rear - locking mechanism is unlocked.

[0034] Preferably, there is at least one unlocking of at least one second - locking mechanism that is automatically and mechanically driven by a pressure on at least a part of a third wheel being higher than a given threshold, where the given threshold corresponds to the wheelchair being loaded on at least a part of the second wheels rather than all of the first wheels. This pressure higher than the given threshold automatically and mechanically triggers at least one lock visual indicator to show that this second - locking mechanism is unlocked.

[0035] Thus, due to this specific dual - stage locking system, the locking of the retractable first wheels can no longer be inadvertently activated under unwanted activation circumstances, even with the help of a distracted pedestrian. Moreover, this locking can actually be activated only when there are steps to climb and when the wheelchair is exactly adjacent to the steps to be climbed.

[0036] Preferably, the unlocking of the first front - locking mechanism is possible only when the second front - locking mechanism is unlocked, and the unlocking of the first front - locking mechanism is mechanically driven by the manual pressure of the user's foot on a first unlocking pedal. The unlocking of the first rear - locking mechanism is possible only when the second rear - locking mechanism is unlocked, and the unlocking of the first rear - locking mechanism is mechanically driven by the manual pressure of the user's foot on a second unlocking pedal.

[0037] Preferably, there is at least one unlocking of at least one first - locking mechanism that is possible only when at least one second - locking mechanism is unlocked, and the unlocking of at least one first - locking mechanism is mechanically driven by the manual pressure of the user's foot on at least one unlocking pedal.

[0038] Thus, due to this specific double - cascade locking system, the locking of the retractable first wheels can virtually no longer be inadvertently activated in the event of an unwanted activation, even with the help of a distracted pedestrian. Additionally, this locking can actually be activated only when there are steps to be climbed and when the wheelchair is precisely adjacent to the steps to be climbed.

[0039] Preferably, the first wheels include: a pair of first front wheels and a pair of first rear wheels, and the second wheels include: a pair of second front wheels and a pair of second rear wheels. The pair of first front wheels is paired with the pair of second front wheels so as to bear the load of the wheelchair when the pair of first front wheels is retracted, and the pair of first rear wheels is paired with the pair of second rear wheels so as to bear the load of the wheelchair when the pair of first rear wheels is retracted.

[0040] Thus, there is a clear pair - by - pair coupling between the first wheels and the second wheels, such that when climbing steps, the second wheels assist the first wheels, but only the first wheels to which they are associated.

[0041] Preferably, from the front to the rear of the wheelchair, there are in sequence: the pair of first front wheels, the pair of second front wheels, the pair of first rear wheels, and the pair of second rear wheels. The retraction of the pair of first front wheels and the retraction of the pair of first rear wheels are not simultaneous.

[0042] Thus, the smooth transfer from a first lower height at ground level to a second higher height at step level (the second higher height is higher than the first lower height) can be carried out step - by - step, that is, first the front part of the wheelchair and then the rear part of the wheelchair, or first the rear part of the wheelchair and then the front part of the wheelchair.

[0043] Preferably, the axis of rotation of the second wheels is fastened to the structure of the wheelchair so as to remain immovable during the retraction of the first wheels.

[0044] The axis of rotation of each pair of second wheels is offset from the axis of rotation of its paired pair of first wheels by a gap G, and the gap depends on the height H of the stairs that the wheelchair is to climb and the difference between the diameter D1 of the first wheels and the diameter D2 of the second wheels.

[0045] The relationship is preferably: G = H-(D1 - D2) / 2.

[0046] Thus, the trade - off between structural simplicity and mechanism efficiency is improved.

[0047] Preferably, the retraction mechanism of the first wheels rotates the first wheels around an axis of rotation that is offset from the axis of rotation of the first wheels.

[0048] Thus, the retraction of the first wheels does not interfere with the operation and rolling of the corresponding second wheels.

[0049] Preferably, the retracting mechanism includes a return spring which, when retraction is no longer required, will return the first wheels to their original non-retracted position, whereupon the first locking mechanism will automatically lock the first wheels in their original non-retracted position.

[0050] Accordingly, the safety of the retracting mechanism is enhanced.

[0051] Preferably, the second wheels are rollers which have a diameter smaller than that of the first wheels, and the circular cross-sectional area of the rollers is at most half that of the circular cross-sectional area of the first wheels.

[0052] Accordingly, the trade-off between structural simplicity and mechanism efficiency is improved. The rollers can be significantly smaller than the wheels as they are intended to be used only in specific situations: climbing over specific steps and remaining on the steps, such as the steps present within a radiological device.

[0053] Preferably, the second wheels are non-retractable.

[0054] Accordingly, the trade-off between structural simplicity and mechanism efficiency is improved because the second wheels of limited size do not need to retract when properly positioned, even when the wheelchair is being driven on the ground outside the radiological device.

[0055] Preferably, the wheelchair further includes: a floorboard which supports the seat, into which the first wheels are retractable, and the second wheels are partially at the height of the floorboard and partially below the floorboard.

[0056] Accordingly, the bulk and overall volume of the wheelchair are further reduced.

[0057] Preferably, the first wheels are retracted by moving relative to the floorboard, and the second wheels remain immovable relative to the floorboard during the retraction of the first wheels.

[0058] Accordingly, the trade-off between structural simplicity and mechanism efficiency is improved.

[0059] Preferably, the wheelchair further includes: the horizontal rotation axes of all the second wheels are fixed relative to the floorboard, the horizontal rotation axes of all the first wheels are movable relative to the floorboard during the retraction of the first wheels, except during the retraction of the first wheels, the horizontal rotation axes of some of the first wheels are fixed relative to the floorboard, and except during the retraction of the first wheels, the horizontal rotation axes of some other first wheels can be vertically oriented relative to the floorboard.

[0060] Accordingly, the manoeuvrability of the wheelchair is further improved.

[0061] Preferably, the wheelchair further includes: a lifting system which is located between the seat and the floorboard and lifts the seat relative to the floorboard.

[0062] Thus, the wheelchair can further adapt to the different sizes of the person sitting thereon.

[0063] Preferably, the seat is radiolucent.

[0064] Thus, this wheelchair can be used more easily within a radiology device.

[0065] Preferably, the wheelchair is for immobile patients in a functional sitting position.

[0066] Thus, this wheelchair can be used more easily in a medical environment.

[0067] Preferably, the height difference between the first wheel and the second wheel is in the range of 5 - 20 cm, or in the range of 8 - 12 cm, or about 10 cm. More precisely, the height difference between the lowermost part of the perimeter of the first wheel (the part that will rest on the ground and roll on the ground) and the lowermost part of the perimeter of the second wheel (the part that will rest on the ground and roll on the ground) is in the range of 5 - 20 cm, or in the range of 8 - 12 cm, or about 10 cm.

[0068] Thus, the overall bulk and overall volume of the wheelchair are further reduced, and at the same time, the height of the steps that this wheelchair can easily climb is still relatively large.

[0069] Preferably, the wheelchair is fully mechanical and passive, so the wheelchair does not include a motor and does not include a power supply.

[0070] Thus, the trade - off between structural simplicity and mechanism efficiency is further improved.

[0071] Preferably, the wheelchair further includes a brake to prevent the wheelchair from rolling, which is activated by the manual pressure of the user's foot on a first brake pedal, and preferably automatically and mechanically triggers a brake visual indicator to show that the brake is activated, and the brake is released by the manual pressure of the user's foot on a second brake pedal.

[0072] Thus, the safety of this wheelchair is further improved.

[0073] Preferably, the wheelchair further includes: two rods, the lengths of the two rods are in the range of 50 cm - 150 cm, preferably about 80 cm, the two rods can be locked in a vertical position, the two rods can be unlocked and tilted at an angle in the range of 30 - 60 degrees, preferably about 50 degrees, relative to the vertical direction, and have handles at the respective distal ends of the two rods.

[0074] Thus, the portability and maneuverability of the wheelchair are further improved.

[0075] Preferably, the radiology system further includes: a first safety device that stops the vertical scanning when detecting a patient body part moving outside a first predetermined area to avoid a collision between the patient body part and the vertically sliding radiation source cover, and a second safety device that stops the vertical scanning when detecting an object or a person outside the radiology device within a second predetermined area to avoid a collision between the object or the person and the vertically sliding radiation source cover.

[0076] Therefore, the safety of disabled or immobile patients sitting in a wheelchair is further improved.

[0077] Preferably, in a square array having three rows from A to C and three columns from 1 to 3: the top view of the L-shaped gantry cover obtains squares C1, C2, C3, B3, A3, the two radiation source covers are respectively located within squares B1 and A2, the patient floor obtains square B2, and square A1 remains completely free and vacant.

[0078] Therefore, the mobility of the wheelchair is further improved, and at the same time, the trade-off between the structural simplicity and the mechanism efficiency of the complete radiology system including the wheelchair and the radiology device is further improved.

[0079] This second object of the present invention is achieved by a mobile patient support including: a base having a top side, a bottom side, a front portion, and a rear portion; a seat configured to receive a patient, the seat being fastened to the top side of the base; a first strut having a proximal end and a distal end, wherein the proximal end is pivotally attached to the bottom side of the base; a first wheel fastened near the distal end of the first strut; a second wheel fastened to the bottom side of the base behind the first wheel; wherein the first strut is pivotable between an extended position and a retracted position, in the extended position the first wheel is positioned further away from the bottom side of the base portion than the second wheel, and in the retracted position the first wheel is positioned closer to the bottom side of the base portion than the second wheel.

[0080] The preferred embodiment includes one or more of the following features, which may be combined partially or fully with this second object of the present invention either individually or together.

[0081] Preferably, the mobile patient support further includes a first locking mechanism that can be configured between the following positions: (1) a locked position, in which the first locking mechanism maintains the first strut in the extended position; and (b) an unlocked position, in which the first locking mechanism retracts the first strut, thereby moving the first wheel towards the bottom side of the base.

[0082] Preferably, the mobile patient support further includes a second locking mechanism configurable between: (1) a first position in which the second locking mechanism maintains the first locking mechanism in its locked position, and (2) a second position in which the first locking mechanism is permitted to transition from the locked position to the unlocked position.

[0083] Preferably, the mobile patient support further includes a visual indicator mechanically coupled to the second locking mechanism and configured to provide an indication as to whether the second locking mechanism is in the first position or the second position.

[0084] Preferably, the second locking mechanism is configured to transition from the first position to the second position when the third wheel is subjected to sufficient force.

[0085] Preferably, the second locking mechanism further includes a third wheel.

[0086] Preferably, the third wheel is positioned relative to the base such that the farthest side edge of the wheel extends farther from the bottom side of the base than the farthest side edge of the second wheel.

[0087] Preferably, the first locking mechanism is configured to transition from the locked position to the unlocked position by a user's foot applying pressure to the first locking mechanism.

[0088] Preferably, the diameter of the first wheel is greater than the diameter of the second wheel.

[0089] Preferably, the patient support is configured to be transferred onto an elevated platform, the height of the elevated platform being greater than the vertical distance between the lowest points of the bottom edges of each of the first wheel and the second wheel.

[0090] Preferred embodiments of any one of the foregoing first and second objects of the present invention include one or more of the previous features, which when combined in part or in whole may be individually or together partially or fully combined with the first object of the present invention or the second object of the present invention or both objects of the present invention.

[0091] Further features and advantages of the present invention will be apparent from the following description of embodiments of the present invention given as non-limiting examples with reference to the accompanying drawings listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] Figure 1 A perspective view showing an example of a wheelchair according to an embodiment of the present invention.

[0093] Figure 2 A side view showing an example of a wheelchair according to an embodiment of the present invention.

[0094] Figure 3 Side view showing an example of the lower part of a wheelchair according to an embodiment of the present invention.

[0095] Figure 4 Perspective view showing an example of the lower part of a wheelchair according to an embodiment of the present invention.

[0096] Figure 5 Side view showing an example of the lower part of a wheelchair according to an embodiment of the present invention in the first stage of climbing stairs.

[0097] Figure 6 Side view showing an example of the lower part of a wheelchair according to an embodiment of the present invention in the second stage of climbing stairs.

[0098] Figure 7 Side view showing an example of the lower part of a wheelchair according to an embodiment of the present invention in the third stage of climbing stairs.

[0099] Figure 8 Side view showing an example of the lower part of a wheelchair according to an embodiment of the present invention in the fourth stage of climbing stairs.

[0100] Figure 9 Side view showing an example of a wheelchair according to an embodiment of the present invention after having climbed the stairs.

[0101] Figure 10 Perspective view showing an example of the lower part of a wheelchair according to an embodiment of the present invention, showing a part of the locking system.

[0102] Figure 11 Top view showing an example of the lower part of a wheelchair according to an embodiment of the present invention, showing a part of the locking system.

[0103] Figure 12 Perspective view showing an example of the lower part of a wheelchair according to an embodiment of the present invention, showing a part of the locking system.

[0104] Figure 13 Perspective view showing an example of the frame of a wheelchair according to an embodiment of the present invention.

[0105] Figure 14 Side view showing an example of the frame of a wheelchair according to an embodiment of the present invention after having climbed the stairs.

[0106] Figure 15 Perspective view showing an example of the frame of a wheelchair according to an embodiment of the present invention on the ground.

[0107] Figure 16 Perspective view showing an example of the frame of a wheelchair according to an embodiment of the present invention partially on a step.

[0108] Figure 17 Perspective view showing an example of the frame of a wheelchair according to an embodiment of the present invention that is entirely on a step. Detailed description

[0109] In all the figures, there is:

[0110] - A longitudinal direction X in a horizontal plane, which corresponds to the front - rear direction with respect to the wheelchair,

[0111] - A transverse direction Y in a horizontal plane, which is orthogonal to the longitudinal direction X,

[0112] - A vertical direction Z orthogonal to the horizontal plane, which is orthogonal to both the longitudinal direction X and the transverse direction Y.

[0113] In all the figures, the second wheel 2 will be referred to indifferently as the second wheel 2 or the roller 2.

[0114] Figure 1 Perspective view showing an example of a wheelchair according to an embodiment of the present invention.

[0115] The wheelchair includes a seat 5 supported by a lifting system 50, which can vertically move the seat 5 and maintain the seat 5 at different heights. The lifting system 50 is supported by a substantially horizontal floor plate 3. A first wheel 1 including two front wheels 11 and two rear wheels 12 is mounted below the floor plate 3.

[0116] The lifting system 50 is located between the seat 5 and the floor plate 3, lifting the seat 5 relative to the floor plate 3. The seat 5 is radiolucent. The wheelchair is for a non - ambulatory patient in a functional sitting position. The wheelchair is completely mechanical and passive, so it includes neither a motor nor a power supply.

[0117] Two vertical rods 51 extend upward from the horizontal floor plate 3, and the free ends of the vertical rods are handles 52. The handles 52 each include an actuator for pivoting the rods 51 about the transverse axis Y. The two rods 51 have lengths in the range of 50 cm - 150 cm, preferably about 80 cm. They can be locked in the vertical position, they can also be unlocked and tilted at an angle in the range of 30 - 60 degrees, preferably about 50 degrees, relative to the vertical direction, and have handles 52 at their respective distal ends.

[0118] Figure 2 Side view showing an example of a wheelchair according to an embodiment of the present invention.

[0119] In addition to the seat 5 and the first wheels 1, the wheelchair further includes second wheels 2 that are higher than the first wheels 1. The first wheels 1 are retractable and, when retracted, are higher than the second wheels 2. The wheelchair actually includes two first front wheels 11 associated with two second front wheels 21, and two first rear wheels 12 associated with two second rear wheels 22.

[0120] Figure 3 Side view showing an example of the lower part of a wheelchair according to an embodiment of the present invention.

[0121] The wheelchair further includes a first front locking mechanism 13 that secures the position of the first front wheels 11 when not retracted, and a first rear locking mechanism 14 that secures the position of the first rear wheels 12 when not retracted.

[0122] The second wheels 2 are rollers 2 that have a diameter smaller than that of the first wheels 1, and whose circular cross-sectional area is at most half of the circular cross-sectional area of the first wheels 1. The circular cross-sectional area of the first wheels 1 is the circular surface of the first wheels 1 visible in the plane Figure 3 that is a plan view. Figure X Z. The circular cross-sectional area of the rollers 2 is the circular surface of the rollers 2 visible in the plane Figure 3 that is a plan view. Figure X Z. The rollers 2 are non-retractable, and their axis of rotation is fixed and immovable relative to the base plate 3. The height difference h between the first wheels 1 and the second wheels 2 is in the range of 5 - 20 cm, or in the range of 8 - 12 cm, or is approximately 10 cm.

[0123] The caster wheels 31 and the corresponding caster wheels 32 have diameters much smaller than those of the rollers 21 and the corresponding rollers 22 to which they are respectively associated, less than half of the diameter of said rollers. The caster wheels 31 and the corresponding caster wheels 32 are associated with the rollers 21 and the corresponding rollers 22 such that when the wheelchair is loaded on the rollers 21 and the corresponding rollers 22, the wheelchair also presses on the caster wheels 31 and the corresponding caster wheels 32, so as to trigger the unlocking of the second locking mechanism, and cause the visual indicators 33 and the corresponding visual indicators 34 to protrude from the upper surface 30 of the base plate 3, mechanically actuated by the caster wheels 31 and the corresponding caster wheels 32, while when the wheelchair is loaded on the first wheels 1, these visual indicators 33 and the corresponding visual indicators 34 are mechanically retracted into the base plate 3.

[0124] Figure 4 Perspective view showing an example of the lower part of a wheelchair according to an embodiment of the present invention.

[0125] The wheelchair further includes a brake for preventing the wheelchair from rolling, which is activated by the manual pressure of the user's foot on the first brake pedal, and preferably automatically and mechanically triggers a brake visual indicator 90 to indicate that the brake is activated. The brake is released by the manual pressure of the user's foot on the second brake pedal. Actuated mechanically by the user's foot pressing on the first brake pedal, the brake visual indicator 90 projects from the upper surface 30 of the base plate 3. Actuated mechanically by the user's foot pressing on the second brake pedal, the brake visual indicator 90 retracts into the base plate 3. The lifting system 50 is actuated mechanically by the user's foot pressing on the lifting pedal 53.

[0126] The base plate 3 further includes a first unlocking pedal 36 and a second unlocking pedal 35. The manner in which the first unlocking pedal 36 and the second unlocking pedal 35 operate will be explained below with reference to the following figures.

[0127] Figure 5 A side view showing an example of the lower part of a wheelchair according to an embodiment of the present invention in the first stage of climbing stairs.

[0128] The existing step is a platform 6 resting on the floor 100. This platform 6 is a lifting platform that can lift its upper surface 60 to different heights so that different parts of the patient's body can be imaged. The wheelchair has partially climbed onto this platform 6 with the upper surface 60. The rear rollers 22 press on the upper surface 60 of the platform 6, thereby bearing the rear load of the wheelchair, such that the first rear wheel 12 is located above the floor 100 and no longer touches this floor 100, and then no longer bears the rear load of the wheelchair. After the rear locking mechanism 14 of the rear wheel 12 has been unlocked by the load of the wheelchair pressing on the third rear caster 32, these rear casters 32 also press on the upper surface 60 of the platform 6, thereby mechanically protruding the rear visual indicator 34 upward from the upper surface 30 of the base plate 3.

[0129] Figure 6 A side view showing an example of the lower part of a wheelchair according to an embodiment of the present invention in the second stage of climbing stairs.

[0130] The wheelchair has partially climbed onto this platform 6 with the upper surface 60. The rollers 22 press on the upper surface 60 of the platform 6, thereby bearing the rear load of the wheelchair and continuing to roll on the upper surface 60 of the platform 6, such that the first rear wheel 12 that has abutted against the platform 6 pivots about the rear retraction axis 18 with its rear base 16 so as to retract into the base plate 3, which is mechanically actuated by the simple pressure of the platform 6 against the first rear wheel 12. At the end of this second stage, the front load of the wheelchair is still on the first front wheel 11.

[0131] Figure 7 A side view showing an example of the lower part of a wheelchair according to an embodiment of the present invention in the third stage of climbing stairs.

[0132] The wheelchair has partially climbed onto the platform 6 having an upper surface 60. The front rollers 21 press against the upper surface 60 of the platform 6, thereby bearing the front load of the wheelchair, such that the first front wheels 11 are located above the floor 100 and no longer contact this floor 100, and then no longer bear the front load of the wheelchair. After the front locking mechanism 13 of the front wheels 11 has been unlocked by the load of the wheelchair pressing on the third front caster 31, these front casters 31 also press against the upper surface 60 of the platform 6, further causing the front visual indicator 33 to project mechanically upward from the upper surface 30 of the base plate 3.

[0133] Figure 8 Side view showing an example of the lower part of a wheelchair according to an embodiment of the present invention in the fourth stage of climbing steps.

[0134] The wheelchair has partially climbed onto the platform 6 having an upper surface 60. The front rollers 21 press against the upper surface 60 of the platform 6, thereby bearing the front load of the wheelchair and continuing to roll on the upper surface 60 of the platform 6, such that the first front wheels 11 that have abutted against the platform 6 pivot about their front base 15 around the front retraction axis 17 so as to retract into the base plate 3, which is mechanically actuated by the simple pressure of the platform 6 against the first front wheels 11. At the end of this fourth stage, the full load of the wheelchair, i.e., the front load and the rear load of the wheelchair, is no longer on any of the first wheels 1, that is, neither on the first front wheels 11 nor on the first rear wheels 12, but on the rollers 2, that is, on the front rollers 21 and the rear rollers 22.

[0135] The first set of wheels 1 includes: a pair of first front wheels 11 and a pair of first rear wheels 12. The second set of wheels 2 as the rollers 2 includes: a pair of second front wheels 21 and a pair of second rear wheels 22. The pair of first front wheels 11 is paired with the pair of second front wheels 21 so as to bear the front load of the wheelchair when the pair of first front wheels 11 retracts into the base plate 3. The pair of first rear wheels 12 is paired with the pair of second rear wheels 22 so as to bear the rear load of the wheelchair when the pair of first rear wheels 12 retracts into the base plate 3.

[0136] From the front to the rear of the wheelchair, there are in sequence: the pair of first front wheels 11, the pair of second front wheels 21, the pair of first rear wheels 12, the pair of second rear wheels 22, and the retraction of the pair of first front wheels 11 and the retraction of the pair of first rear wheels 12 are not simultaneous.

[0137] The rotation axis of the second set of wheels 2 is fastened to the structural base plate 3 of the wheelchair so as to remain immovable during the retraction of the first set of wheels 1. The retraction mechanism of the first set of wheels 1 rotates the first set of wheels 1 about the rotation axis 18 for the first rear wheels 12 or about the rotation axis 17 for the first front wheels 11, and the above rotation axes are offset from the rotation axis of the first set of wheels 1.

[0138] The retraction mechanism includes a return spring (not shown) which, when no longer retracted within the base plate 3, will return the first wheel 1 to its original non-retracted position, and the rear first locking mechanism 14 for the first rear wheel 12 and the front first locking mechanism 13 for the first front wheel 11 will then automatically lock the first wheel 1 one by one in its original non-retracted position.

[0139] The base plate 3 supports the seat 5, and the first wheel 1 is retractable within this base plate 3, more precisely within the housing of the base plate 3, while the second wheel 2 is partly at the height of this base plate 3 and partly below this base plate 3. The first wheel 1 is retracted by moving relative to this base plate 3, while the second wheel 2 remains immovable relative to this base plate 3 during the retraction of the first wheel 1. The base plate 3 of the wheelchair further includes the horizontal rotation axes of all the second wheels 2 fixed relative to this base plate 3, and the horizontal rotation axes of all the first wheels 1 movable relative to this base plate 3 during the retraction of the first wheel 1. Except during the retraction of the first rear wheel 12, the horizontal rotation axis of the first rear wheel 12 is fixed relative to this base plate 3. Except during the retraction of the first front wheel 11, the horizontal rotation axis of the first front wheel 11 can be vertically oriented relative to this base plate 3.

[0140] Figure 9 Side view showing an example of a wheelchair according to an embodiment of the invention after having climbed a step.

[0141] The entire wheelchair is located on the upper surface 60 of the platform 6 which it has climbed. This wheelchair is fully loaded on the rollers 2 which are the second wheels 2, i.e., the front rollers 21 and the rear rollers 22, while all the first wheels 1 which are the first front wheels 11 and the first rear wheels 12 are retracted within the base plate 3 and thus no longer support the load of the wheelchair. The base plate 3 actually abuts against the vertical wall 7 of the radiographic equipment, where the seat 5 abuts obliquely against this vertical wall 7 to obtain more stability, so that an image is taken with as little movement of the seat 5 relative to the radiological equipment as possible.

[0142] Figure 10 Perspective view showing an example of the lower part of a wheelchair according to an embodiment of the invention, showing parts of the locking system.

[0143] Figure 11 Top view showing an example of the lower part of a wheelchair according to an embodiment of the invention, showing parts of the locking system.

[0144] The wheelchair further includes a second front locking mechanism for tightening the locking of the first front locking mechanism, and a second rear locking mechanism for tightening the locking of the first rear locking mechanism, and the second front locking mechanism and the second rear locking mechanism are similar to each other.

[0145] Here, a second rear locking mechanism 14 for fastening the locking of the first rear locking mechanism 4 is shown. There is a locking pin 49 integrated in the base plate 3, which can block or release the rotating disc 40. The rotating disc itself, depending on its rotational position, pushes or pulls two rods 41 and 42, respectively blocking or releasing the safety pins 43 and 44, thereby respectively blocking or releasing the first rear wheel 12.

[0146] When the locking pin 49 is upward (see Figure 10 ), it blocks the rotation of the rotating disc 40, thereby maintaining the rods 41 and 42 immovable. The rods continuously push the safety pins 43 and 44 into the rear base 16, respectively, so as to keep the first rear wheel 12 in a blocked state.

[0147] When the locking pin 49 is downward (see Figure 11 ), it releases the rotation of the rotating disc 40, thereby respectively pulling the rods 41 and 42. The rods in turn pull the safety pins 43 and 44 out of the two rear bases 16, and then become released. Thus, subsequently, once the roller 22 has borne the load of the wheelchair, it is possible to retract the first rear wheel 12 by rotating about the axis 18 of the first rear wheel 12 and its rear base 16.

[0148] Once the locking pin 49 is downward, the rotating disc 40 is rotated by a cable 48, which is pulled by the user's foot pressing the pedal 36 (see Figure 4 ). The pulled cable can form an angle by rotating around the pulley 47.

[0149] The unlocking of the second rear locking mechanism 14 is automatically and mechanically driven by the pressure on the third rear wheel 32 being higher than a given threshold, which corresponds to the wheelchair being loaded on the second rear wheel 22 rather than the first rear wheel 12. This pressure higher than the given threshold automatically and mechanically triggers the lock visual indicator 34, indicating that the second rear locking mechanism 14 is unlocked. The unlocking of the first rear locking mechanism 4 is only possible when the second rear locking mechanism 14 is unlocked, and the unlocking of the first rear locking mechanism 4 is mechanically driven by the user's foot applying manual pressure on the first unlocking pedal 36 (see Figure 4 ).

[0150] In a similar manner, even when Figure 11As can also be understood without being shown, the unlocking of the second front locking mechanism is automatically and mechanically driven by a pressure on the third front wheel 31 that is higher than a given threshold, which corresponds to the wheelchair being loaded on the second front wheel 21 rather than the first front wheel 11. This pressure above the given threshold automatically and mechanically triggers the lock visual indicator 33, indicating that the second front locking mechanism 13 is unlocked. The unlocking of the first front locking mechanism is only possible when the second front locking mechanism 13 is unlocked, and the unlocking of the first front locking mechanism is mechanically driven by the manual pressure of the user's foot on the second unlocking pedal 35 (see Figure 4 ).

[0151] The rear first locking mechanism 14 and the front first locking mechanism 13 work in a similar manner. When the rollers 2 are not on the platform 6, the third small wheels 31 and 32 are not on the platform 6 and they are in the low position. They automatically place the locking pin 49 in the upward position, which prevents the movement of the wheel retraction mechanism. When the rollers 2 and the third small wheels 31 and 32 are on the platform 6, they are pushed upward. This pulls the locking pin 49 downward, thus releasing the movement of the wheel retraction mechanism. The transmission between the third small rear wheel 32 and the locking pin 49 is performed by the rotation of the horizontal rod around the rotation axis indicated by the Figure 10 rotating arrow on it.

[0152] The rear wheel retraction mechanism and the front wheel retraction mechanism work in a similar manner. When the foot pedal is activated, i.e., the pedal 36 for the rear wheel retraction mechanism or the pedal 35 for the front wheel retraction mechanism, this pulls the cable 48, thus causing the rotating disc 40 to rotate. The connecting rods 41 and 42 pull the two safety pins 43 and 44 out of their housings, thus releasing the retraction of the first wheel 1. The rotation of the rotating disc 40 is only possible if the second locking mechanism 14 has first been unlocked by translating the locking pin 49 downward.

[0153] Figure 12 Perspective view showing an example of the lower part of a wheelchair according to an embodiment of the present invention, showing a part of the locking system.

[0154] The rod 42 can push the safety pin 44 into the hole 64 of the first rear base 16 or pull this safety pin 44 out of this hole 64 of the first rear base 16.

[0155] Figure 13 Perspective view showing an example of the frame of a wheelchair according to an embodiment of the present invention.

[0156] The wheelchair is on the floor and ready to roll on the floor on its first wheels 1, that is, on its first front wheel 11 and its first rear wheel 12. The wheelchair is loaded on the first wheels 11 and 12, rather than on the second wheels 21 and 22. The first wheels 11 and 12 are in the working position, that is, in the extended position, and are blocked in this extended position in order to be able to bear the load of the wheelchair.

[0157] Figure 14 A side view showing an example of the frame of a wheelchair according to an embodiment of the present invention after climbing the steps.

[0158] The wheelchair is on the upper surface 60 of the platform 6 and is blocked in this position to allow taking an X-ray image, or after such an X-ray image has been taken, it is ready to roll on this upper surface 60 of the platform 6 on its second wheels 2, that is, on its second front wheel 21 and its second rear wheel 22. The wheelchair is loaded on the second wheels 21 and 22, rather than on the first wheels 11 and 12. The first wheels 11 and 12 are in a retracted position inside the housing of the base plate 3 (the housing of the base plate 3 has been removed here to better show the interior of the base plate 3), and the load of the wheelchair is borne by the second wheels 21 and 22.

[0159] Figure 15 A perspective view showing an example of the frame of a wheelchair according to an embodiment of the present invention on the ground.

[0160] A mannequin 8 playing the role of a patient is sitting on the seat 5 of the wheelchair, and the wheelchair rolls on the floor 100 and enters the X-ray radiology equipment to allow simultaneous frontal and lateral images of this mannequin 8 to be taken.

[0161] Figure 16 A perspective view showing an example of the frame of a wheelchair according to an embodiment of the present invention partially on the steps.

[0162] The mannequin 8 is still sitting on the seat 5 of the wheelchair, and the wheelchair rolls partially on the floor 100 on the first front wheel 11 and partially on the upper surface 60 of the platform 6 on the second rear wheel 22. The first rear wheel 12 is retracted inside the housing of the base plate 3 (this housing of the base plate 3 has been removed here), and the wheelchair is inside the X-ray radiology equipment to allow simultaneous frontal and lateral images of this mannequin 8 to be taken.

[0163] Figure 17 A perspective view showing an example of the frame of a wheelchair according to an embodiment of the present invention completely on the steps.

[0164] The mannequin 8 is still sitting on the seat 5 of the wheelchair, and the wheelchair rolls on the upper surface 60 of the platform 6 on the second front wheel 21 and the second rear wheel 22. The first front wheel 11 and the first rear wheel 12 are retracted inside the housing of the base plate 3 (this housing of the base plate 3 has been removed here), and the wheelchair is inside the X-ray radiology equipment and is correctly positioned at a specific position on the platform 6 where frontal and lateral images of this mannequin 8 can be taken.

[0165] Now, the complete sequence will be described in conjunction with Figure 15 - 16 -17.

[0166] The floor plate 3 of a wheelchair, preferably a medical wheelchair, comprises the following mechanisms:

[0167] - Four first wheels 11 and 12, each equipped with a separate brake,

[0168] - A first wheel retraction mechanism for retracting the first wheels 11 and 12 of the chair when positioning the wheelchair on top of the platform 6 of an X-ray imaging device.

[0169] - A safety lock mechanism for locking the position of the wheelchair once it is mounted on top of the lifting platform 6, as Figure 17 shown above.

[0170] In the initial position, the first wheels 11 and 12 are locked in the vertical position by the first wheel locking mechanism. In this initial position, a patient (or here a mannequin 8 acting as a patient) can transfer from his or her personal wheelchair into a medical wheelchair according to an embodiment of the present invention, and this transfer can be easily performed since it is carried out outside the enclosed space within the cabin of the radiology device. Subsequently, the medical wheelchair and the mannequin 8 (or patient) sitting in the seat 5 of this medical wheelchair can be moved from the transfer area to near the platform 6, as Figure 15 visible above.

[0171] Push the medical wheelchair towards the platform 6 until the rear rollers 22 contact the top 60 of the platform 6. The load is transferred from the first rear wheel 12 to the rear rollers 22; this takes some force since the first rear wheel 12 is a few millimeters lower than the top 60 of the platform 6 to ensure that they are the wheels bearing the load of the medical wheelchair. Push the medical wheelchair until the first rear wheel 12 contacts the side 61 formed by the step of the platform 6 (see Figure 16 ). A visual indicator (34 for the rear rollers 22) shows that the first rear wheel 12 is in the correct position. The safety mechanism unlocks the first rear wheel 12 retraction system.

[0172] The operator activates the pedal 36 (see Figure 4 ), which unlocks the retraction of the first rear wheel 12. This is possible because the first rear wheel locking mechanism 4 has previously been unlocked by the second rear locking mechanism 14. The first rear wheel 12 and its support 16, i.e., its rear base 16, can now rotate about its retraction axis 18 (see Figure 6 ).

[0173] Push the medical wheelchair further towards the platform 6 until the front rollers 21 contact the top 60 of the platform 6. The load of the wheelchair is transferred from the first front wheel 11 to the front rollers 21; this takes some force since the first front wheel 11 is a few millimeters lower than the top 60 of the platform 6 to ensure that they are the wheels bearing the load of the medical wheelchair. Push the medical wheelchair until the first front wheel 11 contacts the side 61 formed by the step of the platform 6 (see Figure 16 ).

[0174] A visual indicator (33 for the front roller 21) shows that the first front wheel 11 is in the correct position. The safety mechanism unlocks the retraction of the first front wheel 11 from the system.

[0175] The operator activates the pedal 35 (see Figure 4 ), which unlocks the retraction of the first front wheel 11. This is possible because the first front wheel locking mechanism was previously unlocked. The first front wheel 11 and its support 15 can now rotate about its retraction axis 17 (see Figure 8 ).

[0176] At Figure 17 , the medical wheelchair is now in the scanning position. An X-ray acquisition is performed using a radiological device. After the X-ray acquisition has been terminated, the medical wheelchair is pulled down from the platform 6. The first wheels 1 are equipped with return springs that place them in the vertical position once they leave the platform 6, first the first front wheel 11 and then the first rear wheel 12 in sequence. Once in the vertical position, these first wheels 1 automatically lock in the vertical position.

[0177] The invention has been described with reference to the preferred embodiments. However, within the scope of the invention, many variations are possible.

Claims

1. A wheelchair, comprising: - A seat (5), - A first wheel (1), wherein the wheelchair further comprises: - A second wheel (2), which is higher than the first wheel (1), and wherein: - The first wheel (1) is retractable so as to be higher than the second wheel (2) when retracted.

2. The wheelchair according to claim 1, wherein, The wheelchair further comprises: - Two first front wheels (11), which are associated with two second front wheels (21), - Two first rear wheels (12), which are associated with two second rear wheels (22).

3. The wheelchair according to claim 2, wherein, The wheelchair further comprises: - A first front locking mechanism, which fastens the position of the first front wheel (11) when not retracted, - A first rear locking mechanism (4), which fastens the position of the first rear wheel (12) when not retracted.

4. The wheelchair according to claim 3, characterized in that, The wheelchair further comprises: - A second front locking mechanism (13), which fastens the locking of the first front locking mechanism, - A second rear locking mechanism (14), which fastens the locking of the first rear locking mechanism (4).

5. The wheelchair according to claim 4, wherein The wheelchair further comprises: - A third front wheel (31), which is associated with the two first front wheels (11) and the two second front wheels (21), - A third rear wheel (32), which is associated with the two first rear wheels (12) and the two second rear wheels (22), - The unlocking of the second front locking mechanism (13) is automatically and mechanically driven by the pressure on the third front wheel (31) being higher than a given threshold, the given threshold corresponding to the wheelchair being loaded on the second front wheel (21) rather than the first front wheel (11), ○ This pressure higher than the given threshold automatically and mechanically triggers a lock visual indicator showing that the second front locking mechanism (13) is unlocked, - The unlocking of the second rear locking mechanism (14) is automatically and mechanically driven by the pressure on the third rear wheel (32) being higher than a given threshold, the given threshold corresponding to the wheelchair being loaded on the second rear wheel (22) rather than the first rear wheel (12), ○ This pressure higher than the given threshold automatically and mechanically triggers a lock visual indicator showing that the second rear locking mechanism (14) is unlocked.

6. The wheelchair according to claim 4 or 5, characterized in that: - The unlocking of the first front locking mechanism is possible only when the second front locking mechanism (13) is unlocked, - and the unlocking of the first front locking mechanism is mechanically driven by the manual pressure of the user's foot on a first unlocking pedal (35), - The unlocking of the first rear locking mechanism (4) is possible only when the second rear locking mechanism (14) is unlocked, - and the unlocking of the first rear locking mechanism (4) is mechanically driven by the manual pressure of the user's foot on a second unlocking pedal (36).

7. The wheelchair according to any one of the preceding claims, characterized in that: - The first wheel (1) comprises: ○ A pair of first front wheels (11) and a pair of first rear wheels (12), - The second wheel (2) comprises: ○ A pair of second front wheels (21) and a pair of second rear wheels (22), - The pair of first front wheels (11) is paired with the pair of second front wheels (21) so as to bear the load of the wheelchair when the pair of first front wheels (11) retracts. - The pair of first rear wheels (12) is paired with the pair of second rear wheels (22) so as to bear the load of the wheelchair when the pair of first rear wheels (12) retracts.

8. The wheelchair according to claim 7, characterized in that: - From the front to the rear of the wheelchair, there are successively: ○ The pair of first front wheels (11), ○ The pair of second front wheels (21), ○ The pair of first rear wheels (12), ○ The pair of second rear wheels (22), - The retraction of the pair of first front wheels (11) and the retraction of the pair of first rear wheels (12) are not simultaneous.

9. The wheelchair according to claim 8, characterized in that, The rotation axis of the second wheel (2) is fastened to the structure of the wheelchair so as to remain immovable during the retraction of the first wheel (1).

10. The wheelchair according to any one of the preceding claims, characterized in that, The retraction mechanism of the first wheel (1) causes the first wheel (1) to rotate about a rotation axis (17, 18) offset from the rotation axis of the first wheel (1).

11. The wheelchair according to any one of the preceding claims, characterized in that: - The retraction mechanism includes a return spring which, when retraction is no longer carried out, will cause the first wheel (1) to return to its original non-retracted position, ○ The first locking mechanism will then automatically lock the first wheel (1) in its original non-retracted position.

12. The wheelchair according to any one of the preceding claims, characterized in that, The second wheel (2) is a roller (2), which has a diameter smaller than the diameter of the first wheel (1), and the circular cross-sectional area of the roller is at most half of the circular cross-sectional area of the first wheel (1).

13. The wheelchair according to any one of the preceding claims, characterized in that, The second wheel (2) is non-retractable.

14. The wheelchair according to any one of the preceding claims, characterized in that, The wheelchair further includes: - A bottom plate (3) which supports the seat (5), - The first wheel (1) can retract into this bottom plate (3), - The second wheel (2) is partly at the height of this bottom plate (3) and partly below this bottom plate (3).

15. The wheelchair according to claim 14, characterized in that: - The first wheel (1) retracts by moving relative to this bottom plate (3), - The second wheel (2) remains immovable relative to this bottom plate (3) during the retraction of the first wheel (1).

16. The wheelchair according to claim 14 or 15, characterized in that, The wheelchair further includes: - The horizontal rotation axes of all the second wheels (2) are fixed relative to this bottom plate (3), - The horizontal rotation axes of all the first wheels (1) can move relative to this bottom plate (3) during the retraction of the first wheels (1), - Except during the retraction of the first wheels (1), the horizontal rotation axes of some of the first rear wheels (12) are fixed relative to this bottom plate (3), - Except during the retraction of the first wheels (1), the horizontal rotation axes of some other first wheels (11) can be vertically oriented relative to this bottom plate (3).

17. The wheelchair according to claim 14 or 15 or 16, characterized in that, The wheelchair further includes: - A lifting system (50), the lifting system: ○ Is located between the seat (5) and the bottom plate (3), ○ Lifts the seat (5) relative to the bottom plate (3).

18. The wheelchair according to any one of the preceding claims, characterized in that, The seat (5) is radiolucent.

19. The wheelchair according to any one of the preceding claims, characterized in that, The wheelchair is for a non-ambulatory patient in a functional sitting position.

20. The wheelchair according to any one of the preceding claims, characterized in that, The height difference between the first wheel (1) and the second wheel (2) is in the range of 5 - 20 cm, or in the range of 8 - 12 cm, or is about 10 cm.

21. The wheelchair according to any one of the preceding claims, characterized in that, The wheelchair is: - Completely mechanical and passive, so the wheelchair: ○ Does not include a motor, ○ Does not include a power supply.

22. The wheelchair according to any one of the preceding claims, characterized in that, The wheelchair further includes: - A brake that prevents the wheelchair from rolling, - This brake is activated by the manual pressure of the user's foot on the first brake pedal, ○ And preferably automatically and mechanically triggers a brake visual indicator to show that this brake is activated, - This brake is released by the manual pressure of the user's foot on the second brake pedal.

23. The wheelchair according to any one of the preceding claims, characterized in that, The wheelchair further includes: - Two rods (51), ○ The length of the two rods is in the range of 50 cm - 150 cm, preferably about 80 cm, ○ The two rods can be locked in a vertical position, ○ The two rods can be unlocked and can be tilted at an angle in the range of 30 - 60 degrees with respect to the vertical direction, preferably about 50 degrees, ○ And have handles (52) at the respective distal ends of the two rods.

24. A radiology system, characterized in that, The radiology system includes: - A wheelchair according to any one of the preceding claims, - And a radiology device, the radiology device including: A frame, which is enclosed within a cover, Patient base plate or platform (6), Two radiation sources, having imaging directions orthogonal to each other, which slide vertically in order to perform a vertical scan of a patient standing on the floor or platform (6). The top view of the frame cover is L-shaped. Each of the two radiation sources: ○ Located at: ■ Outside the L-shaped frame cover, ■ Inside the angular sector of the L, ○ And is enclosed in a cover that slides vertically together with the radiation source it encloses.

25. The radiology system according to claim 24, characterized in that, The radiology system further includes: A first safety device that stops the vertical scanning when a patient body part moving outside a first predetermined area is detected, so as to avoid a collision between the patient body part and the vertically sliding radiation source cover. And a second safety device that stops the vertical scanning when an object or a person is detected outside the radiological device within a second predetermined area, so as to avoid a collision between the object or the person and the vertically sliding radiation source cover.

26. The radiology system according to claim 25, wherein: In a square array having three rows from A to C and three columns from 1 to 3: ○ The top view of the L-shaped frame cover obtains squares C1, C2, C3, B3, A3, ○ The two radiation source covers are respectively located within squares B1 and A2, ○ The patient floor or platform (6) obtains square B2, ○ Square A1 remains completely free and vacant.

27. A mobile patient support, which includes: A base (3) having a top side, a bottom side, a front portion, and a rear portion; A seat (5) configured to receive a patient, the seat (5) being fastened to the top side (30) of the base (3); A first strut having a proximal end and a distal end, wherein the proximal end is pivotally attached to the bottom side of the base (3); A first wheel (1) fastened near the distal end of the first strut; A second wheel (2) fastened to the bottom side of the base (3) behind the first wheel (1); Wherein the first strut can pivot between an extended position and a retracted position, in the extended position, the first wheel (1) is positioned further away from the bottom side of the base (3) portion than the second wheel (2), and in the retracted position, the first wheel (1) is positioned closer to the bottom side of the base (3) portion than the second wheel (2).

28. The mobile patient support according to claim 27, further comprising a first locking mechanism configurable between (a) a locked position and (b) an unlocked position, in which locked position the first locking mechanism maintains the first strut in the extended position; and in which unlocked position the first locking mechanism retracts the first strut, thereby moving the first wheel towards the bottom side of the base.

29. The mobile patient support according to claim 28, further comprising a second locking mechanism configurable between (1) a first position and (2) a second position, in which first position the second locking mechanism maintains the first locking mechanism in its locked position, and in which second position the first locking mechanism is permitted to transition from the locked position to the unlocked position.

30. The mobile patient support according to claim 29, further comprising a visual indicator mechanically connected to the second locking mechanism and configured to provide an indication as to whether the second locking mechanism is in the first position or the second position.

31. The mobile patient support according to any one of claims 29 to 30, characterized in that, The second locking mechanism further comprises a third wheel.

32. The mobile patient support according to claim 31, wherein, The third wheel is positioned relative to the base such that the furthest side edge of the wheel extends further from the bottom side of the base than the furthest side edge of the second wheel.

33. The mobile patient support according to any one of claims 29 to 32, characterized in that, The second locking mechanism is configured to transition from the first position to the second position when the third wheel is subjected to sufficient force.

34. The mobile patient support according to any one of claims 28 to 33, characterized in that, The first locking mechanism is configured to transition from the locked position to the unlocked position by the foot of a user applying pressure to the first locking mechanism.

35. The mobile patient support according to any one of claims 27 to 34, characterized in that, The diameter of the first wheel is greater than the diameter of the second wheel.

36. The mobile patient support according to any one of claims 27 to 35, characterized in that, The patient support is configured to be transferred onto an elevated platform, the height of which is greater than the vertical distance between the lowest points of the bottom edges of each of the first wheel and the second wheel.

Images