A dental chair

Abstract

The invention relates to a dental chair comprising: a seat and a central column supporting the dental chair. The central column is equipped with an actuator that can raise and lower the dental chair. A backrest connected to a motor capable of rotating the backrest around an axis R so that a seated patient's back can be shifted between a first position in which the patients back lays essentially horizontally, and a second position in which the patients back is essentially vertically. The dental chair further comprises an backrest-actuator that can displace the backrest relative to the axis R, so that the distance between the seat and the backrest varies: and a programmable processor with an input unit through which a user can interact with the programable processor, which processor is connected to the backrest's motor and backrest-actuator so that the programable processor can regulate the rotation of the backrest and the distance between the seat and the backrest, the programable processor being programmed so that the distance between the seat and the backrest is regulated depending on the rotation between the backrest and the seat.

Description

[0001] A dental chair

[0002] The invention relates to a dental chair comprising: a seat; a central support supporting the dental chair, which central column is equipped with an actuator that can raise and lower the dental chair a backrest connected to a motor capable of rotating the backrest around an axis R so that a seated patient's back can be shifted between a first position in which the patients back lays essentially horizontally, and a second position in which the patients back is essentially vertically.

[0003] Many modern dental chairs are engineered with mechanisms to adjust the backrest and seat, ensuring optimal ergonomics for dentists and comfort for patients. These mechanisms include manual systems, electric motors, hydraulic systems, and pneumatic systems. Additionally, the design of these moving parts is carefully considered to avoid issues like clothing displacement during adjustments. Such issues have, in prior art techniques, for example been tried to be solved with the help of e.g. slow start and stop mechanisms to ensure that movements start and stop gradually, preventing sudden shifts that could disturb the patient’s clothing. When the backrest moves, the seat can be designed to adjust simultaneously in a coordinated manner, ensuring the patient remains comfortably positioned.

[0004] Dental chairs are designed so that the backrest and seat move in a synchronized manner. This means that as the backrest reclines, the seat adjusts to maintain the patient's natural body alignment, preventing the patient from sliding or their clothing from shifting.

[0005] EP0680307 A1 describes a dental chair provided with a reclining mechanism interlinking the back rest, the chair seat and a leg or foot rest for raising and reclining the back rest, for tilting the chair seat, and for lowering and raising the leg or foot rest together. In order to be able to recline the chair so that its seat back rest and leg or foot rest are both flat and horizontal, the mechanism includes means for disengaging the chair seat so that with the chair seat disengaged and horizontal, the back rest can be reclined and the leg or foot rest can be raised both also to horizontal.

[0006] US2020121537 describes dental chairs used in dental practice. More particularly, the invention relates to an apparatus and a method allowing the movement of chairs synchronizing a first mechanism that reclines the backrest with respect to the seat of chairs, and to a second compensation mechanism that moves the seat along the longitudinal axis of the chair during reclining.

[0007] In prior art, the adjusting positioning of the torso / head has caused problems as an angular rotation of the patient’s torso means that the patient’s head is displaced in the horizontal plane - requiring the dentist to move along. Further, it often happens that the patient’s clothing is affected by this movement.

[0008] It has been shown that these disadvantages can be minimized or completely eliminated when the dental chair further comprises: a backrest-actuator that can displace the backrest relative to its rotational axis R, so that the distance between the seat and the backrest varies: and a programmable processor with an input unit through which a user can interact with the programable processor, connected to the backrest's motor and backrest-actuator so that the programable processor can regulate the rotation of the backrest and the distance between the seat and the backrest, the programable processor being programmed so that the distance between the seat and the backrest is regulated depending on the rotation between the backrest and the seat.

[0009] In an embodiment, the programable processor is programmed so that it controls the motor and backrest-actuator so that the distance between the seat and the backrest is minimized when the motor rotates the backrest in the direction from the second position to the first position and vice versa when the motor rotates the backrest in the direction from the first position to the second position.

[0010] It has surprisingly been shown that precisely these modes of operation will among other reduce problems with clothing parts being pulled apart. In an embodiment, the programable processor is programmed such that an input about the patient's height via the input unit causes the distance between the seat and the back to be regulated accordingly when the backrest is rotated between the first and second positions. It has been found that the programmable controller can be programmed so that a simple input via the input unit as to which of two or more intervals the height of a patient lies within can provide a very advantageous and coordinated control of the rotation of the backrest and the distance between the backrest and the seat.

[0011] In an embodiment, the dental chair comprises a chair actuator that can regulate the horizontal position of the dental chair so that the dental chair can be moved in the horizontal direction of a central axis. There exist various reasons why a dentist may have advantages in being able to move the entire dental chair, typically he / she will be able to minimize disadvantages that are inadvertently created during the manipulation of the seat back, including e.g. that the patient's head has moved.

[0012] In an embodiment, the dental chair comprising a motor-controlled leg rest, which is controlled by the programmable processor, which leg rest can tilt steplessly between a position where it lies essentially in horizontal extension of the seat and a position where it lies in extension of the seat but tilted downwards and approximately perpendicular to it. Being able to lift the legs of a patient can improve the patient wellbeing though it results in better blood circulation to the patient's head.

[0013] In an embodiment, the dental chair's seat is connected to a seat-actuator controlled by the programmable processor, such that it, independently of the other parts of the dental chair, can move the seat back and forth in the dental chairs centre axis’s horizontally direction. In an embodiment, the dental chair's central support comprising a parallelogram-based lifting mechanism. Parallelogram connections are suitable in lifting mechanisms as they ensure that the faces of the mechanisms remain parallel, which - in this embodiment of the invention - ensures that the dental chair and its seat maintain their angle to the horizontal when the seat is adjusted up and down.

[0014] In an embodiment the dental chair's backrest may be rotated, so that a patient lying in the dental chair will have their head lying on a surface that is below the flat plane defined by the surface of the seat. Such a position is well known as an Trendelenburg or approximated Trendelenburg position in which the patient is positioned flat on his / her back with their head level to their body and their legs may be passively raised. This position is often used to help venous return to the heart and restore adequate brain perfusion in individuals with e.g. hypotension.

[0015] Embodiments of the invention will now be explained with reference to the figures, in which: fig. 1 shows the dental chair seen from the side; fig 2 shows the dental chair seen from the front and fig. 3 shows the dental chair, seen from the side, in the position where the backrest is laid down and the leg support is turned up, so that a patient in the chair is practically lying horizontally.

[0016] In figure 1 , an embodiment of the invention is shown. The dental chair comprises a headrest 10, a seat 3, a backrest 2, and a leg rest 4. In connection with the backrest 2, an arrow A indicates that the backrest can move linearly away from and towards the seat 3. This movement can be achieved in many ways, for instance, it may be achieved by using one or more gear and / or rack mechanisms and / or by using one or more linear actuators. The dental chair 1 in the shown embodiment is equipped with a leg rest 4 which preferably is also equipped with a motor / mechanism that can rotate the leg rest as indicated by the arrow P’. Under the dental chair, a central column 5 can be seen. The column 5 is normally equipped with a motor that can raise or lower the dental chair, most often this motor is also a linear actuator.

[0017] To control all these movements, the dental chair according to the invention is equipped with a central programmable computer unit (not shown) provided with an input unit, which can be in the form of a touch display and / or a keyboard, but the input unit can of course also be a wireless-based app, and / or a remote control, so the dental chair can be operated wirelessly via, for example, a remote control or a mobile phone.

[0018] When a dental chair's backrest is tilted around an axis - such as the axis indicted in the figures with reference letter R - which is offset from the axis (approximately at the hips) around which the patient's upper body tilts this often has the disadvantage that the patient's clothing parts that touch the seat 3 are pulled away from the clothing parts that touch the backrest of the dental chair.

[0019] By designing the dental chair with a backrest that moves towards the seat when the backrest is laid down (moved towards horizontal), this disadvantage is minimized.

[0020] In figure 2, the dental chair 1 with backrest 2, seat 3, leg rest, and two armrests is shown from the front, and the central axis C is shown in the figure.

[0021] In figure 3, the dental chair 1 is shown in a position where the backrest 2 is approximately horizontal. The central column 5 in this embodiment is designed as a parallelogram connection that, in addition to the parallelogram link 52, includes a base 50, and a seat block 51. The parallelogram connection 50, 51 , 52 ensures that the seat maintains its angle relative to the horizontal while being adjusted up and down.

[0022] As indicated in figure 3, the axis of rotation R around which the backrest of the dental chair rotates does not coincide with the axis of rotation around which a patient's upper body (torso) rotates when the backrest of a dental chair is raised or lowered as indicated by the arrow P. This is disadvantageous as the patient may experience that the pieces of clothing that touches the seat are being pulled apart from the pieces of clothing that touches the backrest. Furthermore, the adjusting positioning of the torso may also cause problems as an angular rotation of the patient’s torso means that the patient’s head is displaced in the horizontal plane - requiring readjustment of light aimed at the patient’s mouth and further force the dentist to move.

[0023] To overcome or minimize some or all of these disadvantages, the dental chair according to the invention comprises: a backrest-actuator that can displace the backrest relative to its rotational axis R, so that the distance between the seat and the backrest may be adjusted. The dental chair further comprises a programmable processor provided with an input unit through which a user can interact with the programable processor. The programable processor is connected to the backrest's motor and backrest-actuator so that the programable processor coordinates the rotation of the backrest and the distance between the seat and the backrest. These movements are indicted by the arrow A and P.

[0024] As indicated in figure 3, the backrest 2 can preferably be laid down and the legrest 4 raised accordingly, both so far that the patient may be positioned in the so-called Trendelenburg position, in which the patient is positioned flat on their back with their head level to their body, and their legs may be passively raised.

[0025] This position is often used to help venous return to the heart and restore adequate brain perfusion in individuals with, for example, hypotension. As mentioned above, another problem linked to the reclining of a dental chairs backrest is that while the backrest reclines, a patient's head, on which the dentist operates, progressively relocates in space, from a position substantially aligned with her / his hip joint, to a position wherein patient's head is at a marked distance from patient's hip, say in the order of tens of centimeters. This forces the dentist, normally positioned on patient's side or behind the patient, to replace.

[0026] In figure 3 is another horizontal arrow A' shown. The arrow A' indicates that the dentist's chair according to the invention may be equipped with a - not shown - chair-actuator and guide system being capable of moving the chair back and forth in the direction of the arrow A'. By equipping the dental chair with a chair actuator that can move the chair as shown with arrow A', a unique opportunity is achieved for the dental chair - if necessary - to have the position of the chair adjusted according to the both the dentists and the patients' current and individual needs. The size of the thereby achieved movement of the chair will normally be in the order of 0-25, or 0-50 or 0-100cm. and the chair-actuator is normally connected to the thereto accordingly programmed programable controller such that the patient's head is kept - horizontally - in a preferred position while (or after) the backrest is lowered or raised.

[0027] Several different actuators are mentioned in the application. Such actuators are well known to those skilled in the art and they exist in many versions. Several of these actuators - used in the invention - may be of the type: linear actuators, but this is not a requirement. The precise mode of operation or type of the actuators is therefore not decisive and accordingly these will not be described further in this application.

Claims

Claims1 . A dental chair comprising: a. a seat; b. a central support supporting the dental chair, which central support preferably is equipped with an lifting-actuator that can raise and lower the dental chair c. a backrest connected to a motor capable of rotating the backrest around an axis R so that a seated patient's back can be shifted between a first position in which the patients back lays essentially horizontally, and a second position in which the patients back is essentially vertically; characterized in that, the dental chair further comprises: d. a backrest actuator that can displace the backrest relative to the axis R, so that the distance between the seat and the backrest varies: and e. a programmable processor with an input unit through which a user can interact with the programable processor connected to the backrest's motor and the backrest-actuator so that the programable processor can regulate the rotation of the backrest and the distance between the seat and the backrest, the programable processor being programmed so that the distance between the seat and the backrest is regulated depending on the angle between the backrest and the seat.

2. A dental chair according to claim 1 , wherein the programable processor is programmed so that it controls the motor and backrest-actuator so that the distance between the seat and the backrest is reduced when the motor rotates the backrest in the direction from the second position to thefirst position and vice versa when the motor rotates the backrest in the direction from the first position to the second position.

3. A dental chair according to claim 1 or 2, characterized in that the programable processor being programmed so that an input about the patient's height via the input unit causes the distance between the seat and the back to be regulated accordingly when the backrest is rotated between the first and second positions.

4. A dental chair according to any of claims 1-3, characterized in that, the dental chair comprises a chair-actuator being connected to said programable processor, said chair-actuator being capable of regulating the horizontal position of the dental chair so that the dental chair can be moved in the horizontal direction of a central axis.

5. A dental chair according to any of claims 1-4, characterized in that, the dental chair comprising a motor-controlled leg rest, which is controlled by the programmable processor such that the leg rest can be rotated between a position where it lies essentially in horizontal extension of the seat and a position where it lies in extension of the seat but tilted downwards and approximately perpendicular to it.

6. A dental chair according to any of claims 1-5, characterized in that, the dental chair's seat being connected to a seat actuator controlled by the programmable processor, which, independently of the other parts of the dental chair, can move the seat back and forth in the horizontal direction of a central axis.

7. A dental chair according to any of claims 1-6, characterized in that, the dental chair's central support comprises a parallelogram-based lifting mechanism.io8. A dental chair according to any of claims 1-7, characterized in that, the dental chair's backrest may be rotated down below horizontal, so that a patient lying in the dental chair will have their head lying on a surface that is below the plane defined by the surface of the seat.

9. A dental chair according to any of claims 1-8, characterized in that, the chair is mounted for adjustable tilting movement relative to the central column to allow for flat surgery or angled approximate Trendelenburg positions.

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