Medical treatment chair with adjustable backrest and headrest

Abstract

In a medical treatment chair with a backrest (1) and a headrest (2), the headrest (2) is motor-driven and height-adjustable via an electric drive (3) coupled to the backrest (1). Furthermore, it can be manually pivoted about a pivot axis (II) perpendicular to the direction of height adjustment (I) to set an angle of inclination (α) between a plane of the backrest (1) and a plane of the headrest (2). The treatment chair has control means designed to automatically adjust the height position of the headrest (2) via the electric drive (3) when the angle of inclination (α) between the plane of the backrest (1) and the plane of the headrest (2) is manually adjusted.

Description

[0001] The present invention relates to a medical treatment chair according to the preamble of claim 1, which has a backrest and an adjustable headrest arranged thereon. In particular, the present invention relates to a dental treatment chair used in dental practices.

[0002] Performing dental examinations and treatments requires appropriate patient positioning, allowing the practitioner to perform the work ergonomically. At the same time, the patient should also be able to lie comfortably in the chair, regardless of their size. The dental chair should therefore be equally suitable for adults and children of different sizes.

[0003] Dental treatment chairs are therefore typically designed with an adjustable backrest that can be moved from a nearly vertical position to a horizontal position. The patient's head rests on a headrest connected to the backrest, which is height-adjustable. Within the scope of this height adjustability, the distance between the headrest and the backrest can be changed, allowing the treatment chair to be adapted to the patient's height.

[0004] In addition, it is often possible to pivot the headrest around a pivot axis aligned perpendicular to the direction of the height adjustment. This allows the angle of inclination between the backrest and the headrest to be adjusted, making it possible to adjust the patient's head orientation to suit the examination or treatment being performed. For example, examining a patient's upper jaw requires a slightly different head inclination than examining the lower jaw.

[0005] To ensure that the patient continues to rest comfortably in the treatment chair when the headrest's inclination is changed, the height of the headrest must also be adjusted relative to the backrest. In this context, it is known from the prior art that both the adjustment of the headrest's inclination and the associated length compensation—i.e., the adjustment of the distance between the backrest and the headrest—are performed manually. Alternatively, EP 0 517 933 B1 describes a patient chair in which the headrest's inclination can be adjusted using an electric drive, while the length compensation is performed simultaneously using another electric drive.

[0006] Furthermore, US 5,203,609 A describes a dental treatment chair consisting of a base and upper parts, including a seat, a backrest, and a headrest, all of which are adjustable relative to each other. The chair has controllable drive means for varying the inclination and longitudinal displacement of the upper parts relative to the base, whereby the adjustment means can be either manual or controlled.

[0007] Finally, DE 10 2006 055 211 B3 describes an adjustable headrest for a dental workstation, whereby the headrest can be pivoted relative to the backrest of a treatment chair and adjusted longitudinally. Appropriately designed gear elements enable both manual and parallel mechanical adjustment.

[0008] The solution described in the above-mentioned prior art, in particular the fully electric adjustment of the headrest angle and the implementation of length compensation, appears to be a very convenient procedure at first glance, but has proven to be less than optimal in several respects in the past. The initial disadvantage of these known systems is that with motorized adjustment of the headrest, it can only be adjusted at a fixed speed and thus relatively slowly. This often results in a lengthy process of adjusting the treatment chair to suit the patient and the treatment or examination to be performed. Another disadvantage is that in this case, it is only visually noticeable whether the desired angle of the headrest has been achieved.However, there is no direct interaction between the operator - for example the dentist - and the headrest.

[0009] Accordingly, it would be desirable to provide a novel solution that allows for a quick and precise adjustment of the inclination of the headrest of a treatment chair, based on a direct interaction between the operator and the headrest and, at the same time, also allows for a comfortable length adjustment of the headrest.

[0010] The object is achieved by a medical treatment chair having the features of claim 1; advantageous developments of the invention are the subject of the dependent claims.

[0011] The solution according to the invention is initially based on the idea of manually adjusting the inclination of the headrest. This procedure has proven to be preferred because it allows the inclination, and thus the alignment of the patient's head, to be adjusted more quickly and efficiently for the examination or treatment being carried out. However, in contrast to solutions known from the prior art, in which the two adjustments regarding the inclination of the headrest and the associated adjustment of the distance between the backrest and headrest are generally carried out either electronically or by motor or purely manually, the present invention provides for the adjustment of the height position of the headrest to be carried out by motor to compensate for the manual adjustment of the inclination angle.The dentist can then quickly and efficiently adjust the headrest's inclination, which is then automatically adjusted to ensure the patient remains comfortably positioned in the treatment chair. This unique combination of various adjustments results in extremely comfortable and efficient adjustment of the treatment chair's configuration.For this purpose, the treatment chair has control means which have an electronic control circuit and a sensor for detecting the angle of inclination between the plane of the backrest and the plane of the headrest, wherein the control means are designed, after adjustment of the angle of inclination between the plane of the backrest and the plane of the headrest with the aid of the sensor, to generate a control parameter corresponding to the set angle, which is used as an input signal for the electronic control circuit, and to generate a suitable compensation value for controlling the drive with the aid of the control unit depending on the determined angle of inclination.

[0012] According to the present invention, a medical, in particular a dental treatment chair with a backrest and a headrest is therefore proposed, wherein the headrest is coupled to the backrest in a height-adjustable manner by means of a motor via an electric drive and is further manually pivotable about a pivot axis which is oriented perpendicular to the direction of height adjustability in order to be able to adjust an angle of inclination between a plane of the backrest and a plane of the headrest, wherein according to the invention the treatment chair has control means which are designed to motor-control an adjustment of a height position of the headrest via the electric drive when the angle of inclination between the plane of the backrest and the plane of the headrest is manually adjusted, and wherein the control means have an electronic control circuit and a sensor for detecting the angle of inclination between the plane of the backrest and the plane of the headrest and are designed to∘ after adjusting the angle of inclination between the plane of the backrest and the plane of the headrest, using the sensor to generate a control parameter corresponding to the set angle, which is used as an input signal for the electronic control circuit, ∘ and, depending on the determined angle of inclination, using the control unit to generate a suitable compensation value for controlling the drive in order to control it in such a way that ▪ in the event of a reduction in the angle of inclination between the plane of the backrest and the plane of the headrest, a distance between the backrest and the headrest is increased and ▪ in the event of an increase in the angle of inclination between the plane of the backrest and the plane of the headrest, a distance between the backrest and the headrest is reduced.

[0013] The inventive tracking of the height adjustment of the headrest means that, regardless of the inclination of the headrest, the patient's head is always comfortably supported, which is of crucial importance for the trouble-free performance of a treatment or examination.

[0014] Preferably, the sensor can comprise a displacement sensor—particularly in the form of a sliding potentiometer—which is connected to a pivot joint for the headrest via at least one lever. This allows the inclination of the headrest relative to the backrest to be determined in a particularly simple and reliable manner. Alternatively, the sensor could also comprise an inclination sensor in the form of a gyroscope or a rotary potentiometer.

[0015] To ensure that the headrest reliably remains in the position selected by the user, the treatment chair preferably has a locking device for locking the inclination of the headrest, which locking device can be manually unlocked. In particular, the locking device can be unlocked, for example, using a push button or a similar control element located on the headrest. The locking device can comprise at least one blocking cylinder, as is known from comparable solutions in the prior art.

[0016] The core idea of the invention, as already mentioned, is that the adjustment of the angle of inclination of the headrest is carried out manually, whereas the subsequent adjustment of the height setting is carried out motorically with the aid of an electric drive. For this purpose, it is preferably provided that the drive for adjusting the headrest relative to the backrest has a stepper motor controlled by the control means. This can then be coupled to a belt drive or a threaded spindle for adjusting the headrest, so that a reliable and efficient adjustment of the height setting is carried out in this way. The stepper motor is preferably coupled to the belt drive or the threaded spindle via a gear system, wherein the gear system then comprises several gears.In particular, the belt drive may comprise two toothed belts extending parallel to each other on both sides of an elongated guide element to which the headrest is attached, wherein the toothed belts are coupled to the guide element in order to convert a movement of the stepper motor into a movement of the guide element.

[0017] The control means can comprise a further sensor for detecting the height position of the headrest. In this case, the control unit uses the output signal of the second sensor to generate a control signal for the electric drive if the compensation value and thus the desired height position of the headrest has not yet been reached. This second sensor, which is preferably formed by a rotary potentiometer or a Hall sensor, thus simply ensures that, after adjusting the inclination of the headrest, the subsequent length compensation is actually carried out reliably and that the required position of the headrest relative to the backrest is achieved.

[0018] Furthermore, according to a particularly preferred embodiment, it can be provided that a guide of the headrest can be selectively decoupled from the electric drive, whereby, in the decoupled state, manual adjustment of the height position of the headrest is then again possible. This solution could, for example, be used to initially manually adjust the position of the headrest to the patient's height. However, if the inclination of the headrest is manually adjusted at a later time in accordance with the invention, the subsequent required height adjustment is carried out electronically.

[0019] The invention will be explained in more detail below with reference to the accompanying drawings. They show: Figure 1 shows a view of a headrest of a dental treatment chair with the options for adjusting the position and inclination of the headrest; Figure 2 shows a plan view of a backrest and a headrest of a treatment chair according to a preferred embodiment of the present invention; Figure 3 shows a side view of the inventive arrangement of Figure 2 ; Figures 4a - 4d show representations of how the length compensation is carried out depending on the selected inclination of the headrest in the exemplary embodiment according to the invention, and Figure 5 shows a diagram of the procedure of the control means for implementing the automatic length compensation according to the invention.

[0020] Figure 1 shows the usual adjustment options for a headrest of a dental chair with regard to a Figure 1 backrest not shown.

[0021] The headrest designated with the reference number 2 is initially connected via a guide element 9 to a Figures 2 and 3 The headrest 2 is coupled to the backrest 1 of a treatment chair shown in FIG. 1, wherein the headrest 2 can be displaced in a longitudinal direction I parallel to the guide element 9 with the aid of a drive mechanism described in more detail below. This adjustment option serves to adapt the distance between the headrest 2 and the backrest 1 to the size of the respective patient, thus ensuring that the patient can rest comfortably on the treatment chair.

[0022] The actual headrest 2 with the corresponding cushion for supporting the patient's head is pivotally connected to the guide element 9 via a pivot joint 20, so that the headrest 2 can be pivoted relative to the backrest 1 about an axis II, which is aligned substantially perpendicular to the guide element 9 and thus the direction of the linear adjustment I, in accordance with the further double arrow.

[0023] According to the invention, it is initially provided that the pivoting of the headrest 2 is carried out manually. For this purpose, the headrest 2 has a locking device for selectively locking the set inclination 2. In this context, it is already known from the prior art to design the locking device in the form of corresponding blocking cylinders, which are coupled on the one hand to components of the pivot joint 20 and on the other hand engage the opposite end of the head support 13 carrying the headrest 2. These blocking cylinders, which are variable in length, can then be locked in such a way that they maintain a length associated with the corresponding inclination, thereby blocking further pivoting about the axis II. By means of a push button 14 (see Figure 3) or a comparable actuating element, this locking device can then be released accordingly, so that the headrest 2 can subsequently be pivoted. Corresponding solutions for this are known from the prior art, for example, from the applicant's EP 1 138 306 B1.

[0024] Alternative solutions for implementing the aforementioned locking device are also conceivable. It is essential that the treatment chair according to the invention offers the possibility of manually adjusting the inclination of the headrest 2 and then locking the headrest 2 in the desired orientation.

[0025] In contrast to the adjustment of the angle of inclination, the height adjustment of the headrest 2, i.e. the adjustment of the distance between the backrest 1 and the headrest 2, is carried out by means of an electric drive. Figures 2 and 3In the exemplary embodiment shown, a corresponding electric motor 3 is provided in the area of the backrest 1 opposite the headrest 2, which is coupled to a toothed belt 6 via a gear 4. The motor 3, designed as a stepper motor, drives a drive wheel 3a, which transmits the power synchronously via the gear 4 comprising several gears to two toothed belts 6, which run parallel to both sides of the guide element 9 extending from the headrest 2 in the direction of the backrest 1.

[0026] The toothed belts 6 are coupled to the guide element 9 via a guide 7, which runs along two guide rails 8 running parallel to both sides, so that a movement of the toothed belts 6 ultimately results in the guide element 9 being moved into or out of the backrest 1 along direction I. In addition to the two guide rails 8, secure guidance is achieved with the aid of a slide bearing 10, which is provided at the end region of the backrest 1 facing the headrest 2.

[0027] Using a control element not shown in detail in the figures, a dentist or other treating person, for example, initially has the option of controlling the drive in such a way that the distance between the headrest 2 and the backrest 1 is adjusted to the size of the person sitting or lying on the treatment chair. Since this distance initially depends solely on the person's size and is generally adjusted while the backrest 1 is still in a vertical position, this option for adjusting the position of the headrest 2 is also referred to below as height adjustment.

[0028] In accordance with the previous explanations, the height adjustment of the treatment chair according to the invention is motorized via the previously described electric drive. The adjustment of the angle of inclination of the headrest 2, particularly with respect to the backrest 1, is performed manually. As already mentioned, it has been found that for this adjustment of the headrest 2, manually releasing the locking device and subsequently pivoting it manually is more efficient and precise than would be the case with an electric drive.

[0029] In this context, however, it must be considered that after adjusting the angle of inclination of the headrest 2, a corresponding - at least slight - adjustment in the height adjustment must also be made to ensure a comfortable position for the patient at all times. To this end, the invention provides that after manually adjusting the inclination of the headrest 2, the required adjustment of the height position of the headrest 2 is automatically performed using the previously described electric drive.

[0030] The treatment chair designed according to the invention has control means which are responsible for this automatic height adjustment and will be explained in more detail below.

[0031] The control means initially comprise a first sensor 31 for detecting the angle of inclination of the headrest 2 with respect to the backrest 1. In the illustrated embodiment, this sensor 31 comprises a displacement sensor 11 in the form of a sliding potentiometer, which is articulated via a lever 12 to the pivot 20 for the headrest 2. Pivoting the headrest 2 about the axis II leads, due to the coupling via the lever 12, to a change in the electrical resistance of the sliding potentiometer 11, whereby the angle between the plane of the headrest 2 and the plane of the backrest 1 can be determined.

[0032] The resistance value of the displacement sensor 11 is used as the control signal of the sensor 31 for a control electronics unit 30, which then appropriately controls the motor 3 based thereon in order to carry out the height compensation, i.e., the adjustment of the distance between the backrest 1 and the headrest 2. The travel path of the guide element 9 required for this purpose is determined directly by correspondingly specifying the steps on the stepper motor 3, with the aid of a further sensor element 32, which in the illustrated embodiment is designed as a rotary potentiometer - alternatively, the use of a Hall sensor would also be conceivable - detecting whether a desired height position for the headrest 2 has been reached. Upon reaching the desired position, a corresponding signal is then sent to the control unit 30, which then terminates the operation of the stepper motor 3.Furthermore, with the aid of the further sensor element 32, the end positions for the travel path can also be detected, so that the motor 3 then stops automatically when one of the end positions is reached.

[0033] The procedure for adjusting the settings for a headrest 2 according to the solution according to the invention is described in Figure 4 shown.

[0034] Accordingly, Figure 4a First, it is assumed that backrest 1 and headrest 2 are aligned horizontally, so the patient is already in a lying position.

[0035] In a first step, shown in Figure 4b, the distance d between the backrest 1 and the headrest 2 is then first adjusted according to the size of the patient so that, on the one hand, the patient lies comfortably on the backrest 1 and, on the other hand, the head is comfortably supported on the headrest 2. This adjustment is carried out with the aid of the previously described electric drive, with corresponding operating elements being provided for this purpose on the treatment chair or a supply unit (not shown in detail) of a dental treatment station.

[0036] In principle, as an alternative to the motorized height adjustment, it would also be conceivable to decouple the distance between the headrest 2 and the backrest 1 from the electric drive for this initial adjustment, and to perform the height adjustment manually. This, too, would allow for a significantly faster and more efficient adjustment of the treatment chair's basic setting in a first step. Furthermore, the initial height adjustment could, of course, be performed while the backrest 1 is still in a vertical position. In this case, the headrest 2 would move up or down depending on the patient's height.

[0037] After the position of the headrest 2 has been adjusted to the size of the patient, the inclination of the headrest is then manually adjusted, starting from the aligned position in Figure 4bthe angle α between plane III of the backrest 1 and plane IV of the headrest 2 is either reduced ( Figure 4c ) or enlarged ( Figure 4d ), depending on whether, in the case of a dental treatment chair, an examination or treatment of the upper or lower jaw is to be performed. As already mentioned, the angle of inclination α is adjusted manually by first unlocking the locking mechanism described above and then moving the headrest 2 into the desired orientation.

[0038] However, a change in the angle of inclination α of the headrest 2 also requires a corresponding adjustment of the distance d to ensure that the patient continues to be comfortably supported. In particular, it is provided that in the event that the angle α is as in Figure 4c shown, the distance d is slightly increased. However, if the angle of inclination α is increased, as shown in Figure 4dAs shown, the distance d is reduced to compensate for the length in order to avoid overstretching the patient's neck.

[0039] The crucial point here is that this length adjustment is carried out automatically as soon as the headrest angle has been manually adjusted. The procedure of the control means for automatically adjusting the height position is shown in the flow chart of Figure 5 shown.

[0040] In a first step, as explained above, the headrest 2 is adjusted to the patient's height, with the distance d being adjusted accordingly. As explained, this can be done by controlling the electric drive or manually, if necessary.

[0041] In the subsequent step, according to the present invention, the inclination of the headrest is then manually adjusted, with the aid of the first sensor 31 then generating a control parameter corresponding to the set angle α, which is then transferred to the control unit 30.

[0042] Depending on the determined angle of inclination, the control unit 30 then generates a suitable compensation value α for controlling the electric motor 3. In the case of a lower jaw treatment, i.e., an upward tilt adjustment, the motor 3 is controlled such that the guide element 9 is moved out of the backrest 1 to increase the distance d. In a corresponding manner, the control circuit controls the stepper motor 3 in the case of an upper jaw treatment, in which the headrest 2 is tilted downward, such that the motor 3 retracts the guide element 9 into the backrest 1.

[0043] The travel path is determined by specifying the steps, with the second sensor element 32 determining after each step whether the desired end position has already been reached. If this is not the case, motor 3 continues to be controlled accordingly, since the corresponding compensation value has not yet been reached. However, if the desired compensation value has been reached after a corresponding motor step, further operation of motor 3 is stopped, since the corresponding length compensation has been completed.

[0044] This makes the treatment chair extremely easy to use, as the user only needs to manually adjust the headrest's inclination, and the corresponding length adjustment is then carried out fully automatically. At the same time, the headrest's orientation can be adjusted much more quickly and efficiently to suit the desired treatment, as manual adjustment of the inclination angle is significantly faster and more convenient than with a motorized control.

[0045] Overall, a treatment chair is provided in which the positioning and adjustment of a headrest in relation to a backrest of the treatment chair can be carried out in a very efficient and comfortable manner.

Claims

1. Medical, in particular dental, treatment chair having a backrest (1) and a headrest (2), wherein the headrest (2) is coupled to the backrest (1) in a height-adjustable manner by motor via an electric drive (3) and is furthermore manually pivotable about a pivot axis (II) oriented perpendicular to the direction of height adjustability (I), so as to be able to set an angle of inclination (α) between a plane of the backrest (1) and a plane of the headrest (2), characterized in that the treatment chair has control means which, upon manual adjustment of the angle of inclination (α) between the plane of the backrest (1) and the plane of the headrest (2), are designed to control an adjustment of a height position of the headrest (2) by motor via the electric drive (3), wherein the control means comprise an electronic control circuit (30) and a sensor (31) for detecting the angle of inclination (α) between the plane of the backrest (1) and the plane of the headrest (2), and wherein the control means are designed for the following: i. after adjustment of the angle of inclination (α) between the plane of the backrest (1) and the plane of the headrest (2), to generate, with the aid of the sensor (31), a control parameter corresponding to the set angle (α), which control parameter is used as an input signal for the electronic control circuit (30), ii. and, depending on the determined angle of inclination (α), to generate, with the aid of the control unit (30), a suitable compensation value for actuation of the drive (3), so as to control the latter in such a way that • in the event of a reduction in the angle of inclination (α) between the plane of the backrest (1) and the plane of the headrest (2), a distance (d) between the backrest (1) and the headrest (2) is increased, and • in the event of an increase in the angle of inclination (α) between the plane of the backrest (1) and the plane of the headrest (2), a distance (d) between the backrest (1) and the headrest (2) is reduced.

2. Medical treatment chair according to Claim 1, characterized in that the sensor (31) has a displacement sensor (11) in the form of a sliding potentiometer, which is hinged via at least one lever (12) on a swivel joint (20) for the headrest (2).

3. Medical treatment chair according to Claim 1 or 2, characterized in that the drive (3) for adjusting the headrest (2) with respect to the backrest (1) has a stepper motor (3) actuated by the control means.

4. Medical treatment chair according to Claim 3, characterized in that the stepper motor (3) is coupled to a belt drive (6) or a threaded spindle for adjusting the headrest (2).

5. Medical treatment chair according to Claim 4, characterized in that the stepper motor (3) is coupled to the belt drive (6) or the threaded spindle via a gear mechanism (4), wherein the gear mechanism (4) comprises a plurality of gearwheels.

6. Medical treatment chair according to Claim 5, characterized in that the belt drive (6) has two toothed belts which extend parallel to each other on both sides of an elongate guide element (9) to which the headrest (2) is attached, wherein the toothed belts are coupled to the guide element (9) in order to convert a movement of the stepper motor (3) into a movement of the guide element (9), and wherein preferably a gearwheel of the gear mechanism (4) is coupled in each case to one of the two toothed belts.

7. Medical treatment chair according to any one of the preceding claims, characterized in that the control means have a second sensor (32) for detecting the height position of the headrest (2), and the control unit (30) generates a control signal for the electric drive with the output signal of the second sensor (32) if the compensation value has not yet been reached.

8. Medical treatment chair according to Claim 7, characterized in that the second sensor (32) is formed by a rotary potentiometer or a Hall sensor.

9. Medical treatment chair according to any one of the preceding claims, characterized in that a guide of the headrest (2) can be decoupled from the electric drive (3), wherein in the decoupled state a manual adjustment of the height position of the headrest (2) is possible.

10. Medical treatment chair according to any one of the preceding claims, characterized in that it has a locking device for locking the inclination of the headrest (2), which can be unlocked manually, for example with the aid of a pushbutton (14).

11. Medical treatment chair according to Claim 10, characterized in that the locking device comprises at least one blocking cylinder.

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