WO2024023270A1

WO2024023270A1 - Ophthalmological apparatus comprising a magnetic chin rest

Info

Publication number: WO2024023270A1
Application number: PCT/EP2023/070933
Authority: WO
Inventors: Annika KOSCHORREK; Axel KEIM; Young Woo Lee; Chang Sung Kim
Original assignee: Carl Zeiss Vision International Gmbh
Priority date: 2022-07-28
Filing date: 2023-07-27
Publication date: 2024-02-01

Abstract

The present invention is directed to an ophthalmological apparatus (1) comprising a chin rest (2), characterized in that the chin rest (2) is configured to be releasably mountable on the apparatus (1) via magnetic attachment. Further, the present invention also relates to a chin rest (2) comprising a magnetic element (4).

Description

OPHTHALMOLOGICAL APPARATUS COMPRISING A MAGNETIC CHIN REST

SPECIFICATION:

FIELD OF THE INVENTION

The present invention relates to an ophthalmological apparatus and a chin rest thereof using magnetic attachment.

BACKGROUND

Ophthalmological apparatuses for eye measurement, eye examination or eye treatment have a chin rest to stabilize and fix a subject’s head at a proper location during examination, measurement, or treatment of the subject eye. This is to align the subject’s eye at a proper position (e.g., centration for eye examination in autorefractor) by adjusting the head position. The chin rest together with a forehead rest determines and adjusts the positioning of the head with respect to the apparatus by movement in vertical direction so that the head is properly placed and fixed between the chin rest and the forehead rest during the operation.

Generally, a chin rest is a unit connected to and motorized by a chin rest support. In this regard, ophthalmological apparatuses already in the market are designed to have a chin rest that is substantially an integral part of the apparatus. This means that the chin rest is an integral part of the apparatus or almost permanently attached to the chin rest support by an interference fit, a screwed connection, etc., requiring considerable amount of force or manipulation for detachment. Most of the chin rest supports are motorized so that they can move vertically.

For instance, Zeiss i. Profiler provides a chin rest as an integral part of the apparatus itself, the chin rest forming a single integral unit with the chin rest support. In Huvitz Auto Ref-Keratometer HRK-9000A, a chin rest is connected to a chin rest support via an interference fit, which is a form of fastening between two tight fitting mating parts that produces a joint held by friction after the parts are pushed together. Therefore, the chin rest cannot be separated from the chin rest support without applying substantial amount of force and dedicating time and effort. Both Topcon KR-800S and Zeiss Visuref 100 use a screwed connection between a chin rest and a chin rest support. The conventional chin rest substantially integrated to the apparatus is difficult to clean and maintain. Due to the recently increased importance of disinfection and sterilization of products or things that frequently go through contact with many different people, a need for a chin rest that is easy to clean and maintain has been increased. CN20763762U takes an approach of using disposable sheath that can be put on the top of the chin rest which is cumbersome and not environment friendly.

In addition, during operation of ophthalmological apparatus, as hand(s) of a subject is likely to be placed near an upper surface of the apparatus where the chin rest rests on, there is a risk that the subject injures or clamps his/her fingers when the chin rest comes all the way down to the surface of the apparatus. That is, while being attached to the chin rest support, the chin rest will be moved up or down during positioning of a subject’s head by adjusting the length of the chin rest support. With a resulting gap between the chin rest and the surface of the ophthalmological apparatus by the height adjustment of the chin rest support, the subject may clamp fingers, for example by placing fingers on the surface of the apparatus where the chin rest will eventually rest on when the chin rest support comes down to the lowest level, i.e. , the level the same as the surface of the apparatus. In such a case, the gap disappears as the chin rest support comes down near to the same level as the surface of the apparatus and the chin rest meets the surface of the apparatus where the fingers of the subject are frequently placed, thereby causing injury to the subject’s hands or fingers. Conventionally, this problem has been solved by design follows function, meaning that the chin rest and the chin rest support are designed to have or maintain a substantial gap from the surface of the ophthalmological apparatus. This kind of injury can be also prevented by using countermeasures such as force detection by the motor in the chinrest, and/or chin rest support or automatic stop at a predetermined distance. However, this technology can be expensive and requires more development and design effort.

CN215078330U relates to a portable ophthalmological apparatus and provides a magnetic chin rest which is detachable from a chin rest placing table to make the apparatus as compact as possible. CN215078330U provides a magnetic chin rest, however, as it focuses on providing a portable apparatus, it fails to recognize the problem of the finger injuries and clamps, and here, the magnetic connection is not used to prevent the finger injuries and clamps. As apparent from its figures, the magnetic connection here fails to deliver any safety measure for the subject but only used for the portability of the apparatus. This apparatus still has a danger of finger injuries and clamps due to a chin rest placing table which is connected to the shrink strut and has a width larger than the shrink strut. That is, during the operation (height adjustment), nothing would come between the chin rest and the chin rest placing table or between the chin rest and the surface of the apparatus, as the chin rest placing table is wider than the chin rest and the chin rest is not in direct contact with the surface of the apparatus even when the shrink strut is adjusted to its shortest range. The finger clamp can be only caused between the chin rest placing table and the surface, which are not connected with magnetic attachment.

As such, the conventional ophthalmological apparatuses which adjust the height of the chin rest with vertical movement of a part connected to the chin rest still has an unresolved risk of subject’s injury.

SUMMARY OF THE INVENTION

Starting from CN215078330U, it is therefore an object of the present invention to provide a chin rest of an ophthalmological apparatus which is easy to clean and maintain, and at the same time can prevent the subject from injury in an economical way.

The purpose of the present invention is achieved by an ophthalmological apparatus and a chin rest thereof, wherein the attachment of the chin rest to a chin rest support of the apparatus is realized by magnetic attachment, and the magnetic attachment is configured to be detached when a foreign object is caught (i) between the chin rest and the chin rest support and/or (ii) between the chin rest and at least a part of an upper surface of the apparatus in direct contact with the chin rest, i.e. , where the chin rest rests on.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides an ophthalmological apparatus comprising a chin rest which is releasably mountable on the apparatus via magnetic attachment. The chin rest of the present invention therefore can be easily attached to or detached from the apparatus, leading to ease of maintenance and cleaning compared to the conventional devices where chin rest cannot be or at least cannot be easily disassembled from the apparatus. Simultaneously, the feature of magnetic attachment removes the risk of finger injuries of the subject caused by finger clamp between the chin rest and the chin rest support and/or the surface of the apparatus.

In the context of the present invention, the term “ophthalmological apparatus” refers to an apparatus for measurement, examination, diagnosis and treatment of diseases and disorders of the eye, for example, biometer, keratometer, topographer, and/or autorefractor.

The term “chin rest” is a part attached to an ophthalmological apparatus to aid in positioning of the subject’s chin, ultimately the head, during operation of the apparatus. The chin rest usually has a recess in a shape of a chin (chin cup) so that the subject’s head can be firmly and comfortably held by putting the chin on the recess.

The term “chin rest support” is a part of an ophthalmological apparatus configured so that a chin rest can be mounted thereon and/or attached thereto. A chin rest support can be in a form of strut or pillar. A chin rest support can move in a vertical direction (up and down) to adjust the position of the chin rest, leading to a proper positioning of a subject’s head. The vertical length of the chin rest support can be adjusted to be shortened and/or extended depending on the proper position of the head of the subject.

The chin rest support can be configured to go inside the adjacent part of the ophthalmological apparatus to shorten the length. In a further embodiment, at least one surface of the apparatus is configured to be in direct contact with the chin rest. For instance, the chin rest has a larger width than the width of the chin rest support, thereby the chin rest will be in direct contact with at least one surface of the apparatus, mostly adjacent to a magnetic element of the chin rest support, when the chin rest support is lowered to its short length. At its shortest length, the level of the chin rest support becomes substantially the same as the adjacent surface of the ophthalmological apparatus, meaning that the chin rest support is almost completely retracted into the apparatus at its shortest length. In such a case, the chin rest support will be generally at the same level as the upper surface of the apparatus where the chin rest rests on. In one embodiment, the chin rest support can be completely retracted into the apparatus. With this feature, contrary to CN 215078330U where the chin rest support has a chin rest table which is not shrank into the apparatus, the chin rest support of the present invention eliminates the risk of finger injuries that may be caused by the chin rest support.

Generally, the movements of the chin rest support are realized by manual adjustments (with the help of, for example, a joystick or buttons) or using a drive unit, for example, a motor, providing semi- or fully automatic adjustments.

In one embodiment, the apparatus of the present invention comprises a chin rest support on which a chin rest is mounted, wherein the chin rest support is configured to move vertically. As the chin rest and the chin rest support are attached via magnetic force which can be readily loosened under a specific condition, it was found that converting the rotation movement of a drive unit into a vertical movement of the chin rest support is suitable. Unlike a direct vertical movement, such a conversion of forces allows the chin rest support to move more smoothly suitable for the magnetic attachment between the chin rest and the chin rest support. Direct vertical movement of the chin rest support such as shrink strut such as in CN215078833U may jeopardize stable magnetic attachment of the chin rest to the apparatus.

To be specific, the vertical movement of the chin rest support is driven by a drive unit configured to be rotatable. In one embodiment, the drive unit may be a drive shaft. The drive unit converts its rotation to the vertical movement of the chin rest support. This is implemented by the drive unit having a screw thread formed on its one end and the chin rest support having a screw thread on its one end, wherein the screw thread of the drive unit and the screw thread of the chin rest support are screw- coupled to convert a rotary motion of the drive into a vertical reciprocating motion of the chin rest support. In one embodiment, the chin rest support is capable of sliding movement in a vertical direction. For this, the chin rest support further comprises a means for vertical movement of the chin rest support. The means for vertical movement of the chin rest support is configured to prevent the chin rest support from rotating. For instance, the means for vertical movement can be in a rod shape extended in a vertical direction, enabling the sliding movement of the chin rest support.

The magnetic attachment between the chin rest and the chin rest support of the ophthalmological apparatus enables easy and quick detachment of the chin rest from the ophthalmological apparatus. The chin rest releasably mounted on the chin rest support via magnetic attachment is configured to provide an attachment to the chin rest support of the apparatus tight enough to ensure stable and precise positioning of the subject’s head, and further, it also enables the loosening and release of the chin rest from the chin rest support in a case where the subject happens to put the finger between the chin rest and the surface of the ophthalmological apparatus. In one embodiment, the magnetic attachment has a magnetic force at a strength which enables the chin rest support and the chin rest to be separated when a foreign object is caught therebetween or between the chin rest and the upper surface of the apparatus. Hence in addition to the advantages mentioned above, the chin rest of the present invention can prevent the subject’s injury during the operation of the apparatus with a very simple manner.

The goal of the present invention can be achieved by magnetic elements forming magnetic attachment. The present invention provides an ophthalmological apparatus which comprises a chin rest comprising a first magnetic element. In this regard, the present invention also provides a chin rest which comprises a first magnetic element. Further, the ophthalmological apparatus of the present invention comprises a chin support which comprises a second magnetic element. In a further embodiment, the present apparatus can comprise a chin rest comprising a first magnetic element and a chin rest support comprising a second magnetic element.

The term “magnetic element” refers to magnets, which are also referred to as permanent magnet and produce their own persistent magnetic field even in the absence of an applied magnetic field, as well as magnetic materials, which are also referred to as temporary magnet and can produce a magnetic field in response to an applied magnetic field (magnetism), and thus become magnetized in the presence of a magnetic field. Magnetic elements can also be any materials or combinations of materials that are magnetically attracted to one another and generate magnetic field and force. Examples of magnet are neodymium iron boron (NdFeB or NIB), samarium cobalt (SmCo), ferrite (ceramic magnets, e.g., BaFe2O3 or SRFe2Os) and alnico magnet (Al-Ni-Co). Magnetic materials may be, for example, a ferromagnetic material or ferrimagnetic materials such as irons, iron alloys, or steels.

In one embodiment, the magnetic attachment in the present invention can be realized by the first magnetic element of the chin rest coupled to a second magnetic element of the chin rest support. The coupled magnetic elements generate magnetic field and force, and tract each other, thereby forming the magnetic attachment. The magnetic force refers to magnetic traction between the magnetic elements which provides magnetic attachment.

The magnetic attachment of the present invention is configured to generate a magnetic force that is sufficient to mount and fix the chin rest on the chin rest support so that the subject’s head can be stably positioned and fixed on the chin rest, and at the same time allows for easy detachment of the chin rest from the chin rest support. For example, the chin rest is fixed to the chin rest support so that the chin rest is not moved or detached by the force introduced by the subject or subject’s chin during the measurement, but on the other hand can be released only by applying a force opposite to the direction of the magnetic traction between the chin rest and the chin rest support such as putting a finger between the chin rest and the surface of the ophthalmological apparatus where the chin rest rests on. In other words, the first magnetic element and the second magnetic element are configured to be coupled by a magnetic force at a strength which enables the first magnetic element and the second magnetic element to be separated when a foreign object is caught (i) between the chin rest and the chin rest support and (ii) between the chin rest and the at least a part of the surface of the apparatus where the chin rest rests on.

Therefore, the magnetic attachment between the chin rest and the chin rest support can be readily released when a finger is put between the chin rest and the surface of the ophthalmological apparatus. As a result, even before the finger is injured by being clamped between the chin rest and the surface of the ophthalmological apparatus, the chin rest is immediately loosened or released from the chin rest support, and thus the injury of the subject can be easily prevented. This requires neither additional complicated system such as sensor or automated stop nor separate design means for preventing the subject from being injured during the operation of the apparatus such as eye measurement, etc.

In one embodiment, at least one of the first and the second magnetic elements can be a magnet. In another embodiment, the magnet can be selected from the group consisting of neodymium iron boron, samarium cobalt, ferrite and alnico magnet. In a further embodiment, at least one of the first and the second magnetic elements may comprise neodymium iron boron. In another further embodiment, one of the first magnetic element and the second magnetic element comprises neodymium iron boron and the other comprises ferrite. By using neodymium iron boron as a magnetic element, even stronger magnetic attachment which ensures firm and stable holding of the subject’s head can be achieved, while still providing detachment of the chin rest by a relatively small force to prevent the subject’s injury.

If more stable attachment is required for the operation of the ophthalmological apparatus, the chin rest of the present invention can be configured to have additional attachment with the ophthalmological apparatus. Here, additional attachment refers to an attachment other than the magnetic attachment. For this purpose, the chin rest or the chin rest support may further comprise an additional means for attachment. The term “additional means for attachment” refers to the any attachment between two components except for the magnetic attachment. In a preferred embodiment, the additional means for attachment also provides easy and simple attachment and detachment. For example, the additional means for attachment can be a pair of protrusion and a hole, or a snap joint. In one exemplary embodiment, the chin rest support comprises at least one hole which is coupled with at least one corresponding protrusion of the chin rest, or vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS Further features, properties and advantages of the present invention will become apparent from the following description of exemplary embodiments of the invention with reference to the drawings.

FIG 1 A and FIG 1 B are respectively an external perspective view and a vertical cross-sectional view which show the structure of the apparatus according to the present invention.

FIG 2 is an internal perspective view which shows the internal structure of the apparatus according to the present invention.

FIG 3 is a cross-sectional view showing the vertical movement of the chin rest support of the present invention.

FIG 4 is a cross-sectional view showing the vertical movement of the chin rest support and the release of the chin rest when a foreign object is inserted beneath the chin rest and above the chin rest support.

FIG 5A and 5B are the front view and rear view of a first exemplary embodiment of a chin rest of the present invention.

FIG 6 depicts a first exemplary embodiment of a chin rest support of the present invention where the chin rest illustrated in FIG 5 can be mounted on.

FIG 7 is the rear view of a second exemplary embodiment of a chin rest of the present invention.

FIG 8 depicts a second exemplary embodiment of a chin rest support of the present invention where the chin rest illustrated in FIG 7 can be mounted on.

FIG 9A to 9D show a one embodiment of an ophthalmological apparatus for measurement of biometric data of an eye where a chin rest is releasably mounted on the chin rest support of the apparatus via magnetic attachment. Figure 1A shows the apparatus according to the present invention where the chin rest support (not shown) is shrunk tto its shortest length and completely retracted into the apparatus 1 . Figure 1 B shows inside the apparatus where the chin rest support 3, 26 is almost completely retracted into the apparatus. As shown in Figure 1 B, the apparatus of the present invention comprises: a chin rest 2, 34 with a second magnetic element 5, 32, a chin rest support 3, 26 with a first magnetic element 4, 28, and a drive unit 24.

The drive unit 24 can be a rotating drive shaft 24 with a drive 22. The drive unit 24 is rotatably connected to the apparatus 1 . Here, the drive unit 24 is connected to the chin rest support 3, 26 via a screw thread so as to be rotatable. One end (specifically the lower end) of the drive shaft 24 is coupled to a drive 22 such as a driving motor, so that the drive shaft 24 rotates by means of the rotary motion of the drive 22. The other end (specifically the upper end) of the drive shaft 24 has a screw thread for converting the rotary motion of the drive shaft 24 into a vertical reciprocating motion of the chin rest support 3, 26. The chin rest support 3, 26 has a screw thread 27a, 27b which is coupled to the screw thread of the drive unit 24, and thus is capable of sliding movement in the vertical direction.

As shown in the figure, the chin rest support 3, 26 may further comprise a second magnetic element 5, 32 which forms magnetic attachment with a first magnetic element 4, 28 of the chin rest support.

Figure 2 shows the chin rest support 3, 26 and the drive unit 24 separately from the apparatus. Here, two guide holes 26a, 26b are formed on the upper surface of the chin rest support 3, 26 to deliver more stable connection between the chin rest support 3, 26 and the chin rest 2, 34. Further, a vertical driving guide 25 which is in a rod shape and extends in the vertical direction enables sliding movement of the chin rest support 3, 26 in the vertical direction. Optionally, bearings 21 can be provided at the drive unit 24 to prevent friction.

Figure 3 shows the operation of the chin rest support 3, 26 and the chin rest 2, 34 where no foreign object interrupts between the chin rest 2, 34 and an upper surface 7 of the apparatus 1 where the chin rest 2, 34 rests on. The screw thread 27a, 27b of the chin rest support 3, 26 is screw-coupled to the screw thread formed on the drive unit 24, thereby converting the rotary motion. As shown in Figure 3A, when the drive unit 24 rotates in a particular direction (clockwise or anticlockwise depending on the direction the screw thread is formed in), the chin rest support 3, 26 moves upward; whereas, as shown in Figure 3B, when the drive unit 24 rotates in the other direction, the chin rest support 3, 26 moves downward. Under normal circumstances where no foreign object exists between the chin rest 2, 34 and the upper surface 7 where the chin rest 2, 34 rests on, the chin rest support 3, 26 and the chin rest 2, 34 move downward as a single unit while being attached via magnetic attachment. In this case, the chin rest 2, 34 rests directly on the upper surface 7 of the apparatus 1 .

On the other hand, Figures 4A and 4B show the operation of the chin rest 2, 34 and the chin rest support 3, 26 when a foreign object (P, 8) has been inserted below the chin rest. As shown in Figure 4A, the chin rest support 3, 26 moves upwards due to the rotation of the drive unit 24, and as shown in Figure 4B, if there is a foreign object (P, 8) below the chin rest 2, 34 and above the upper surface 7, the chin rest support 3, 26 moves downward normally until the foreign object (P, 8) is caught under the chin rest 2, 34, i.e. , between the chin rest 2, 34 and the upper surface 7 of the apparatus 1 where the chin rest 2, 34 rests on. As the chin rest support 3, 26 comes further down, force is exerted to the chin rest 2, 34 from below as the foreign object (P, 8) is caught between the chin rest 2, 34 and the apparatus 1 , thereby separating, the first magnetic element 4, 28 and the second magnetic element 5, 32. With this operation, injury of a subject (P, 8; for example, finger) can be prevented.

Figure 5A shows a front view and Figure 5B shows a rear view of a first exemplary embodiment of a chin rest 2 according to the present invention. The chin rest 2 is configured to be releasably mounted on a chin rest support 3 of an ophthalmological apparatus 1 via magnetic attachment. The chin rest 2 comprises a first magnetic element 4 for the magnetic attachment.

Figure 6 shows a chin rest support 3 on which the chin rest 2 of Figures 5A and 5B is configured to be releasably mounted on. The chin rest support 3 comprises a second magnetic element 5. The first magnetic element 4 is coupled to the second magnetic element 5 and provides magnetic attachment. Figures 7 and 8 show a second exemplary embodiment of the present invention where the chin rest 2 and the chin rest support 3 have additional means for attachment 9a, 9b with an ophthalmological apparatus 1 other than magnetic attachment provided by the magnetic elements 4, 5. As shown in Figure 7, the chin rest 2 comprises two protruding parts 9a and 9b, and as shown in Figure 8, the chin rest support 3 comprises two holes 26a matching the protruding parts 9a and 9b. These additional means for attachments can provide more stable fixation of the chin rest 2 to the chin rest support 3 as needed.

Figure 9 shows an ophthalmological apparatus 1 where the chin rest 2 of Figure 7 is releasably mounted on the chin rest support 3 of Figure 8 via magnetic attachment. The magnetic attachment is generated between the first magnetic element 4 and the second magnetic element 5. The apparatus 1 of Figure 9 is an ophthalmological apparatus for measurement and analysis of biometric data of an eye of a subject. In Figure 9A, the chin rest support 3 is in its shortest length and the upper surface 7 of the ophthalmological apparatus 1 is in a direct contact with the chin rest 2. The upper surface 7 is the surface of the apparatus 1 where the chin rest 2 rests on. There is no space or gap between the chin rest 2 and the surface 7 of the ophthalmological apparatus 1 . In Figure 9B, the chin rest support 3 is elongated to its maximum height to adjust the positioning of a subject’s head, and thus a space is generated between the chin rest support 3 and the surface 7 of the ophthalmological apparatus 1 . In Figure 9C, while a finger 8 of the subject is put in the space created between the chin rest 2 and the surface 7 of the ophthalmological apparatus 1 , the chin rest support 3 shortens its length, making the chin rest 2 to come down to the lowest level, almost being in a direct contact with the upper surface 7 of the ophthalmological apparatus 1 . Here, the finger 8 of the subject is in a risk of being clamped between the chin rest 2 and the surface 7 of the ophthalmological apparatus 1 . Figure 9D shows that the chin rest 2 releasably mounted on the chin rest support 3 can be readily detached or loosened from the chin rest support 3 just by the finger lying therebetween, and thus prevents injury of the finger.

Claims

CLAIMS:

1 . An ophthalmological apparatus (1 ) comprising a chin rest (2, 34) attached to a chin rest support (3, 26) via magnetic attachment, characterized in that the magnetic attachment is configured to be detached when a foreign object (8) is caught between the chin rest (2, 34) and the chin rest support (3, 26) and/or between the chin rest (2, 34) and at least a part of an upper surface (7) of the apparatus (1 ) where the chin rest (2, 34) rests on.

2. The apparatus (1 ) according to Claim 1 , characterized in that the chin rest (2, 34) is at least partially in direct contact with the at least a part of the upper surface (7) of the apparatus (1 ).

3. The apparatus (1 ) according to Claim 1 or 2, characterized in that the chin rest support (3, 26) is configured to be completely retracted into the apparatus (1 ) to be generally at the same level as the upper surface (7) of the apparatus (1 ).

4. The apparatus (1 ) according to any one of Claim 1 to 3, characterized in that the chin rest support (3, 26) moves vertically.

5. The apparatus (1 ) according to any one of Claims 1 to 4, characterized in that the chin rest support (3, 26) is coupled to a drive unit (24) which is configured to be rotatable.

6. The apparatus (1 ) according to any one of Claims 1 to 5, characterized in that the chin rest support (3, 26) is configured to move vertically by the rotation of the drive unit (24).

7. The apparatus (1 ) according to any one of Claims 1 to 6, characterized in that a screw thread formed on one end of the drive unit (24) and a screw thread (27a, 27b) formed on one end of the chin rest support (3, 26) are screw coupled. The apparatus (1 ) according to any one of Claims 1 to 7, wherein the chin rest (2, 34) has a first magnetic element (4, 28) and the chin rest support (3, 26) has a second magnetic element (5, 32), characterized in that the first magnetic element (4, 28) and/or the second magnetic element (5, 32) are at least one selected from the group consisting of neodymium iron boron, samarium cobalt, ferrite and alnico magnet. The apparatus (1 ) according to any one of Claims 1 to 8, characterized in that the chin rest support (3, 26) comprises an additional means for attachment (26a, 26b). The apparatus (1 ) according to any one of Claims 1 to 9, characterized in that the chin rest (2, 34) comprises an additional means for attachment (9a, 9b). The apparatus (1 ) according to any one of Claims 1 to 10, characterized by further comprising a means for vertical movement (25) of the chin rest support (3, 26). The apparatus (1 ) according to any one of Claims 1 to 11 ,

Characterized in that the additional means for attachment (9a, 9b) of the chin rest (2, 34) and the additional means for attachment (26a) of the chin rest support are The apparatus (1 ) according to Claim 10, characterized in that the means for vertical movement (25) is configured to prevent the chin rest support (3, 26) from rotating.