EP1396213B1 - Synchronised mecanism for office chairs - Google Patents

Abstract

The synchronising mechanism is biased by a spring assembly (23) which has at least one coil compression spring (24) mounted parallel to the sliding direction of the seat support (4) and associated with its own abutment arm (25) whose front end is attached to the base support (1) and whose rear end freely extends to form an abutment (27) for the rear support of the compression spring. The at least one compression spring is supported by its front end on an abutment (28) formed on the seat support. To adjust the pretension of the compression spring the associated abutment arm is mounted on the base support longitudinally displaceable in the longitudinal direction of the seat.

Description

The invention relates to a synchronous mechanism for office chairs with the im The preamble of claim 1 specified features, as described in DE 198 10 768 A 1 or based on an earlier application of the Applicant DE 101 25 994 A1 are known.

Under the name "synchronous mechanism" assemblies are in the seat substructure of an office chair meant for a coupled, a certain relative movement of the seat and backrest to each other provide with bringing kinematics. This is on a chair column a base support placed on the one to a pivotable about a transverse axis, hingedly connected to the base support seat support and on the other also pivotable about a transverse axis, hinged to the base support connected backrest support are stored. On the seat carrier is the usually with a padded seat provided seat of the office chair assembled. The backrest support, which is commonly used by the Actual synchronous mechanism extends to the rear, contributes to one after Above extending boom, the backrest of the office chair.

Seat support and backrest support are coupled so articulated that a Pivoting movement of the backrest to the rear - as for example caused by leaning on the chair user to the backrest can be - a lowering movement of the rear edge of the seat down induced. This correlated seat-back movement brings one considerable comfort advantage with it and is for orthopedic reasons he wishes.

In order for a pure pivotal coupling of the backrest support with the Base and seat support a pivoting of the backrest and seat to at the bottom of the back, one degree of freedom must be introduced into the mechanics be, which is a displacement of the seat support to the rear simultaneous pivoting around its front end allows. Therefor disclose the two documents mentioned above to the state the technique of a rotary-sliding joint between the base plate and the front End of the seat carrier. Depending on whether and how strong in the sliding-swivel movement the seat support an increase in the seat leading edge desired is, the slot-like sliding guide for the seat support is more likely steep, as in DE 198 10 768 A1 or rather flat, as in DE 101 25th 994 A1.

Another basic issue with synchronous mechanisms is in their spring action against the pivoting backwards. For this For example, a variety of spring designs are known in the art. In the synchronous mechanism according to DE 198 10 768 A 1 is the combination a gas and helical compression spring provided, which is considered relative high-building unit extends under the seat support. The one attack point this spring arrangement is the front bearing end of the seat support, with its rear end, the spring assembly is in an abutment supported the cone seat of the seat support.

The provided in the construction according to DE 101 25 994 A1 spring arrangement based on two thigh springs housed in the base plate are. The one leg of the spring is in an adjustment in the base support housed, whereas the second leg upwards in the direction Seat support protrudes, which has a corresponding abutment on this Leg supports and thus against its backward Swing direction is applied.

Both spring assemblies of the prior art take a considerable amount Part of the available installation space in the base carrier so that its free design is set relatively narrow limits. Especially become when using such known synchronous mechanisms the base carriers for reasons of aesthetics and aesthetics relatively bulky Have fairings to the spring assembly and the associated Hide adjusting elements as far as possible.

On the problem of adjustability of the bias of the spring assembly Reference is made to DE 100 08 453 C2, which is a spring package with zuund wegschaltbaren spring units for varying the spring preload and thus reveals counterforce against pivoting. The spring arrangement itself is here however between the base carrier and a one-piece, Combined seat-backrest support arranged as a whole is pivotable to the rear. This does not provide a synchronous mechanism per se represents.

The invention is based on the object, a synchronous mechanism for Office chairs to improve so that the spring arrangements in a constructive Simplicity particularly compact and especially in a narrower spatial To arrange proximity under the seat carrier, so that the area of the base carrier essentially free, while achieving the greatest possible freedom of design remains.

• die Federanordnung mindestens eine im wesentlichen parallel zur Schieberichtung des Sitzträgers flach unter diesem angeordnete Schraubendruckfeder aufweist, wobei
• für jede Schraubendruckfeder ein Widerlagerausleger vorgesehen ist, dessen vorderes Ende am Basisträger angelenkt ist und dessen rückwärtiges Ende frei auskragend ein Widerlager für die rückwärtige Abstützung der Schaubendruckfeder bildet, und
• sich die mindestens eine Schraubendruckfeder jeweils mit ihrem vorderen Ende an einem am Sitzträger gebildeten Widerlager abstützt.

This object is achieved by the features stated in the characterizing part of claim 1, which

• the spring arrangement has at least one substantially parallel to the sliding direction of the seat support flat below this arranged helical compression spring, wherein
• an abutment arm is provided for each helical compression spring whose front end is hinged to the base support and the rear end of which freely cantilevered forms an abutment for the rearward support of the Schaubendruckfeder, and
• the at least one helical compression spring is supported in each case with its front end on an abutment formed on the seat support.

By the specified construction, the entire spring arrangement practically only about its front end with the remaining kinematics of Synchronous mechanism connected. Starting from the front end of the abutment boom, that at the height of the turn-slide joint between seat support and base support is arranged, the spring arrangement projects virtually horizontally back along the seat support. Due to the flat design it has a very low height. Furthermore, since any fasteners missing in the direction of the backrest or base wearer Below, this section can be made of other design and design parts of the chair are received in any way.

The basic construction of the spring arrangement according to the abutment arm also allows preferred developments in which the adjustment the bias of the spring assembly in a simple manner bewerkstelligbar is. So the abutment boom needs only in the seat longitudinal direction be slidably mounted. By a longitudinal displacement changes the Position of the abutment for the rearward support of the helical compression spring, either stronger or weaker under corresponding Changing the bias voltage is compressed. Preferred dimensions becomes the displacement of the abutment arm by a control shaft with eccentric cam realized.

According to a further preferred embodiment is as a spring arrangement a spring assembly of several helical compression springs provided whose Total prestress by different gradation of the individual Eccentric cam of the control shaft can be varied in narrow steps. this has On the one hand the advantage that a good tunability of the opposing force in the Synchronous mechanism achievable with a wide range of absolute variation is. In contrast to the construction according to the aforementioned DE 100 08 453 C2 is in this case to a Zu- and Wegschaltbarkeit individual Springs completely omitted.

Further preferred embodiments of the invention see the execution the abutment boom as rods in front, on which the helical compression springs are set up. This can be the helical compression springs supported by a support strip on the abutment of the seat support, in a Bearing recess of the abutment is pivotally mounted slide. The support the helical compression spring towards the seat support is improved by because due to the movement of the seat support plate back down at an actuation of the synchronous mechanism a certain tilt angle in to compensate for the support of the helical compression spring.

Further preferred embodiments relate to the training the bearing head of the respective abutment boom in the form of a frame, on the one hand for the storage of the abutment boom on the base support and on the other hand as an attack surface for the eccentric cam of the control shaft is used.

According to further preferred embodiments is at least one Abutment boom provided at the rear end of an additional abutment which is adjustable in the seat longitudinal direction. So that can be on this abutment boom seated helical compression spring in its basic bias be varied, so that together with the adjustability the abutment boom itself at least two different drag ranges for adapting the synchronous mechanism to light or heavyweight persons are provided. Within this Areas can then about the actual adjustment of the abutment boom a fine adjustment be made.

Finally, in a further variant of the invention, the at least one Abstützausleger designed as a control shaft, on the one hand by a Actuator on the base support rotatably driven and on the other hand with her provided at the rear end with an adjustable abutment stop is. This is spindle-shaped by a shaft rotation in the direction of the spring force the helical compression spring adjustable so that only by the Actuation of the actuator, the bias of the helical compression springs is easily adjustable over wide ranges.

Preferably, the actuator is controlled by a manually operable actuating shaft formed in the front area of the base, which has a Deflection gear is coupled to the front end of the control shafts. In order to is the adjustment of the spring preload in a convenient way a knob on the side of the chair protruding end of the actuating shaft to accomplish.

A structurally simple storage of the adjusting waves results from that in a seated on a Umlenkgetriebewelle bearing bracket are rotatably mounted with their front end. The reversing gear is for Achieving a compact design as a bevel gear between each a control shaft and one driven by the actuating shaft Transmission shaft formed.

Fig. 1 und 2

eine Seiten- und Frontansicht einer Synchronmechanik in einer ersten Ausführungsform,

Fig. 3

einen im wesentlichen horizontalen Schnitt durch die Synchronmechanik entlang der Schnittlinie III-III nach Fig. 1,

Fig. 4

ein Vertikalschnitt entlang der Schnittlinie IV-IV nach Fig. 3,

Fig. 5 und 6

Schnitte analog Fig. 3 und 4 mit veränderter Federvorspannung,

Fig. 7 und 8

zentral gelegte Vertikalschnitte durch die Synchronmechanik gemäß der Schnittlinie VII-VII nach Fig. 3 mit unterschiedlichen Stellungen des Zusatz-Widerlagers,

Fig. 9, 10 und 11

Schnitte analog den Fig. 1, 3 und 7 in nach hinten verschwenkter Stellung der Synchronmechanik,

Fig. 12

eine perspektivische, ausschnittsweise Darstellung einer Synchronmechanik in einer zweiten Ausführungsform von schräg hinten, sowie

Fig. 13 und 14

eine Draufsicht bzw. Seitenansicht der Synchronmechanik gemäß Fig. 12.

Further features, details and advantages of the invention will become apparent from the following description in which an embodiment of the subject invention is explained in more detail with reference to the drawings. Show it:

Fig. 1 and 2

a side and front view of a synchronous mechanism in a first embodiment,

Fig. 3

3 is a substantially horizontal section through the synchronizing mechanism along the section line III-III of FIG. 1,

Fig. 4

a vertical section along the section line IV-IV of Fig. 3,

FIGS. 5 and 6

Sections analogous to FIGS. 3 and 4 with modified preload,

FIGS. 7 and 8

centrally placed vertical sections through the synchronous mechanism according to the section line VII-VII of FIG. 3 with different positions of the additional abutment,

FIGS. 9, 10 and 11

Sections analogous to FIGS. 1, 3 and 7 in the backward pivoted position of the synchronizing mechanism,

Fig. 12

a perspective, partial view of a synchronous mechanism in a second embodiment of obliquely behind, as well as

FIGS. 13 and 14

a top view and side view of the synchronous mechanism of FIG. 12th

The basic structure of the synchronous mechanism will be described below with reference to FIGS. 1 to 4 explained. Thus, a base support 1 is provided as the supporting part, in the area of its rear end with a cone seat 2 for attaching the synchronizing mechanism to the upper end of a (not shown) is provided chair column. Other basic components of the synchronous mechanism are the backrest support 3 and the seat support 4. The backrest support 3 is shortly before the cone seat 2 via a transverse axis. 5 pivotally mounted on the base support 1. It consists of two obliquely Rear top extending side struts 6, 7, the rear end in a only schematically indicated Lehnenbasis 8 open.

In the front end region of the widening forward base support 1 on both sides of the central longitudinal plane M are two upwardly projecting bearing posts 9, 10 integrally formed in which as a transverse axis an actuating shaft 11 with a Turn knob 12 is rotatably mounted at one end.

The substantially plate-shaped seat support 4 has in the region of his at the front two downwardly projecting, lateral cheeks 13, 14 on, the with a SL in the seat longitudinal direction to the rear slightly sloping slot 15, 16 are provided. With these slots 15, 16 sits the seat carrier 4 on the control shaft 11, whereby by the engagement of these two components a rotary-sliding joint 17 between base and seat support 1, 4 is formed is, d. H. the seat support 4 can pivot about the control shaft 11 and simultaneously relative to move in the direction of the slots 15, 16.

In the region of its rear end of the seat support 4 with two is also side, downwardly projecting bearing lugs 18, 19 provided, the together with a corresponding, upstanding bearing projection 20, 21 on the two side struts 6, 7 of the backrest support third form a pivot bearing about a transverse axis 22.

For acting on the synchronous mechanism against the synchronous adjustment from the basic position shown in Figs. 1 to 4 out is designated as a whole with 23 spring arrangement, the four parallel to each other, on both sides of the central longitudinal plane M in a common horizontal plane arranged helical compression springs 24.1 to 24.4 (hereinafter referred to by the common reference numeral 24, unless a single helical compression spring is a separate discussion required). For each helical compression spring 24 is in each case an abutment arm 25.1 to 25.4 provided, the front end pivotable relative to the base support 1 via a bearing head 26.1 to 26.4 is articulated. The rod-shaped shaft of the abutment boom 25th protrudes freely to the rear and is there with an abutment projection 27 provided. At this the rear end of the Helical compression springs 24 from.

Its front end sits on a transverse to the seat longitudinal direction SL and horizontal extending, in cross-section semicircular support strip 28 as Abutments, with their semi-cylindrical, forward facing Lateral surface in correspondingly cylindrical bearing recesses 29 at the rear end of the cheeks 13, 14 of the seat support 4 are supported. In addition, 25 more, from the seat support between the abutment boom 4 downwardly projecting intermediate posts 30 present, with the Bearing recesses 29 aligned bearing recesses 31 for additional Counter support of the support bar 28 have. The compressive force of the between the abutment projection 27 and the support bar 28 clamped Helical compression springs 24 acts on the seat support 4 forward in the in Fig. 1 to 4 shown basic position.

The abutment boom 25 pass with their rod-shaped shaft Support strip 28 in the rest via feedthrough openings 32nd

The bearing head 26 at the front end of the abutment arm 25 is as formed at least frame or box-shaped part, whose parallel to the seat longitudinal direction SL extending side frame walls 33 respectively are provided with a slot 34, with which the abutment boom 25th pivotable on the control shaft 11 and in the seat longitudinal direction SL relative thereto is slidably mounted. On the control shaft 11 are within the bearing heads Eccentric cam 35.1 to 35.4 rotatably connected to the control shaft 11, at the respective forward facing eccentric edge 36 each the front frame wall 37 of the bearing head 26 is supported. The contact between the frame wall 37 and 36 Exzenterflanke is through Compressive force of the helical compression springs 24 secured.

For the basic configuration of the synchronous mechanism is to be noted that the spring assembly 23 due to the bias of the helical compression springs 24 of the seat support 4 relative to the base support 1 is applied to the front is, so that he with the rear ends of his oblong holes 15, 16 at the Adjusting shaft 11 rests in the basic position shown in Fig. 1 to 4. Of the Backrest support 3 is here in its maximum upright position.

Now, if the bias of the helical compression springs 24 are changed, so only the control shaft 11 needs to be rotated. Their eccentric cams 35 then move the abutment boom 25, for example on forward, so that the rearward abutment projection 27 closer to the support bar 28 is brought. The helical compression springs 24 are thereby more compressed and exert a greater compressive force on the Support strip 28 and thus the seat support 4. As from the drawings is not clear, the eccentric cam 35 different Exzentrizitätsgrade and gradients have, so that different Helical compression springs 24 on actuation of the control shaft 11 different strongly compressed or relieved.

To another adjustment for the bias of the inner To create helical compression springs 24.2 and 24.3, is an adjustable additional-Wider-camp 38 provided. This is primarily about one transversely to the seat longitudinal direction SL vertically arranged, plate-shaped Slider 39, with two bearing holes 40 on the two inner abutment arms 25.2, 25.3 slidably guided in the seat longitudinal direction SL is. This slider 39 is between the two helical compression springs 24.2, 24.3 and their abutment projection 27.2, 27.3 used. It acts with another eccentric cam shaft 41 together, the eccentric cam 42 is located centrally in the central longitudinal plane M and the slide 39 of applied to the rear.

The bearing of the eccentric cam shaft 41 via two bearing struts 43.1, 43.2, each extending from the bottom of the bearing heads 26.3, 26.3 parallel to the lower abutment arms 25.2, 25.3 extend to the rear. At their free ends, these bearing struts 43 four upright standing bearing plates 44.1 to 44.4, which are aligned with each other Bearing eyes 45 are provided. In these sits the eccentric camshaft 41, which is actuated by a lateral knob 46.

If now the bias of the spring assembly 23 to a heavier Person to be adjusted, so via the knob 46, the eccentric camshaft 41 actuated, and the eccentric cam 42 shifts the Slider 39 on the abutment arms 25.2, 25.3 forward. The Helical compression springs 24.2, 24.3 are under increasing the pressure force more compressed. The achievable by the control shaft 11 adjustment the spring force is retained, since upon actuation of the actuating shaft 11 the entire additional abutment 38 is moved along, so that the two already compressed compressed coil springs 24.2, 24.3 be further compressed.

The operation of the synchronous mechanism can be with reference to FIGS. 9 to 11 in conjunction with FIGS. 1 to 4 explain. This is how it works when pushing back pivoted the backrest of the backrest support 3 to the rear, the thus the seat support 4 back down around the turn-slide joint 17 pivots. The support bar 28 moves closer to the end of the Ablagerausleger 25 out, so that the helical compression springs 24 stronger be compressed and thus build up a higher counterforce. The Rotary sliding movement can be performed until the control shaft 11 at the rear end of the slots 15, 16 hit the seat support.

If the backrest is relieved, then the seat support 4 by the Schraubenendruckfedem 24 pivoted back to the top, with the backrest support 3 mitverschwenkt. This movement is in turn by striking the actuating shaft 11 at the front end of the slots 15, 16 limited.

A second embodiment of a synchronous mechanism according to the invention is shown in FIGS. 12 to 14. To avoid repetition It should be noted in this context that the basic elements of the Synchronous mechanism, such as base support 1, backrest support 3 and seat support 4 with their mutual coupling via transverse axes 5, 22 and the Rotary sliding joint 17 with the embodiment according to FIGS. 1 to 11 to match. In this respect, for such constructive and functional matching elements in the embodiment of FIG. 12 to 14 matching reference numerals used and it will become an explanation related to the corresponding statements refer to Figs. 1 to 11.

In the following, only the alternative design and storage of the the helical compression springs 24 bearing abutment boom 25 described become. Accordingly, these abutment booms 25 are indeed turn hinged with its front end on the base support 1 in principle pivotable, However, in the linkage as a whole with 50 designated actuator for a rotation of acting as a control shaft 51 abutment arm 25 integrated. This actuator 50 has a direction transverse to the extension direction the adjusting shafts 51 rotatable below it on the base support 1 mounted actuating shaft 52 which, to one side of the base support. 1 protrudes and is provided there with a knob 53. Within the basic carrier 1 is the actuating shaft 52 with a gear 54 of a reduction gear 55 provided, the output-side gear 56 on a also mounted in the base support 1 intermediate shaft 57 is seated. This intermediate shaft 57 is completed by coaxial attachable stub shaft 58, on each of which cone gears 59 sit. These form with corresponding bevel gears 60 at the front ends of the Abstützausleger 25 forming adjusting shafts 51 each a bevel gear 61, which in turn with the reduction gear 55 the total so designated deflection gear 49 results. This will turn the Actuating shaft 52 transformed into a rotational movement of the adjusting shafts 51.

The control shafts 51 are at their rear end respectively with threads 62 provided with which spindle nuts 63 are engaged. These spindle nuts 63 are by a common, transverse to the extension direction the adjusting shafts 51 extending abutment bar connected to the each helical compression springs 24 are supported with their rear end. Whose front end is - as in the embodiment of FIG. 1 - to one on the seat support 4 in a semicircular bearing shell (in FIGS. 12 to 14 not visible) pivotally mounted support bar 28 supported.

It remains nachzutragen that the support bar 28 sweeping the front Ends of the adjusting shafts 51 in bearing brackets 65 rotatably mounted in pairs are, in turn, with bearing extensions 66 on the intermediate shaft 57th are pivotally mounted. Thus, the control shafts 51 are not just theirs Rotatable longitudinal axis, but also about the intermediate shaft 57 pivotally stored, so that the adjusting shafts 51, the slight tilting movement of the seat support 4 can perform at the bottom. In this movement is the seat support 4 with the support bar 28 against the force of the helical compression springs 24 shifted to the rear. This drag is through a Adjustment of the rear abutment bar 64 variable.

It should be noted that in Figs. 12 to 14 components, such as two Stellwellen 51 on the left half of Figs. 12 and 14 and there located parts of the deflection gear 49, the left leg of the Backrest support 3 and the seat support 4 for better clarity the construction were omitted.

Claims (15)

1. A synchronizing mechanism for office chairs, comprising

   a base carrier (1) to be placed on a chair column,

   a backrest carrier (3), which is articulated to the base carrier (1) such that it is pivotable about a transverse axis (5), ,

   a seat carrier (4), which is pivotable about a transverse axis (11) in the region of its front end via a turning-and-sliding joint (17) and slideable in the longitudinal direction (SL) of the seat together with the base carrier (1), and coupled with the backrest carrier (4) such that it pivots in the region of its back end about a transverse axis (22), as well as

   a spring arrangement (23) to actuate the synchronizing mechanism to counter its synchronized adjusting motion of the seat carrier (4) and backrest carrier (3),

      characterized in that

   the spring arrangement (23) incorporates at least one helical compression spring (24) disposed essentially parallel to the sliding direction of the seat carrier (4), flat underneath the same, wherein

   for each helical compression spring (24) a counter-bearing extension arm (25) is provided, the front end of which is articulated to the base carrier (1) and the rear-facing end of which, freely projecting, forms a counter bearing (27) for the rear support of the helical compression spring (24), and

   the at least one helical compression spring (24) is supported in each case with its front end on a counter bearing (28) formed on the seat carrier (4).
2. A synchronizing mechanism according to claim 1, characterized in that to adjust the pretension of the at least one helical compression spring (24), the associated counter-bearing extension arm (25) is supported slideable in the longitudinal seat direction (SL) on the base carrier (1).
3. A synchronizing mechanism according to claim 2, characterized in that the counter-bearing extension arm (25) is slidably supported on the seat carrier (4) by means of a bearing head (26) on an adjusting shaft (11) forming the transverse axis of the tuming-and-sliding joint (17), said adjusting shaft (11) carrying in each case one eccentric cam (35) for adjusting the associated counter-bearing extension arm (25).
4. A synchronizing mechanism according to claim 3, characterized in that a spring package of multiple helical compression springs (24) is provided, the combined pretension of which is variable in narrow steps by means of a varying gradation of the individual eccentric cams (35) of the adjusting shaft (11).
5. A synchronizing mechanism according to any of the above claims, characterized in that the counter-bearing extension arms (25) are designed as rods on which the helical compression springs (24) are placed.
6. A synchronizing mechanism according to any of the above claims, characterized in that the at least one helical compression spring (24) as a counter bearing for the seat carrier (4) is supported via a bearing strip (28) extending perpendicular to the longitudinal seat direction (SL), which is pivotably slide-mounted in a bearing-cutout.
7. A synchronizing mechanism according to claim 3, characterized in that the bearing head (26) of the given counter-bearing extension arms (25) is designed as a frame, the frame walls (33) of which that extend parallel to the longitudinal seat direction (SL) have an elongated-hole type bearing cutout (34), by means of which the counter-bearing extension arm (25) is slidably supported on the adjusting shaft (11).
8. A synchronizing mechanism according to claim 7, characterized in that the front frame wall (37) of the given bearing head frame (26) is actuated by the associated eccentric cam (35).
9. A synchronizing mechanism according to any of the above claims, characterized in that at least one counter-bearing extension arm (25) is provided at its rear-facing end with a supplemental counter bearing (38) that is adjustable in the longitudinal seat direction (SL).
10. A synchronizing mechanism according to claim 9, characterized in that the adjustable supplemental counter bearing is formed by a slider (39) that is slidably guided on the counter-bearing extension arm (25), said slider (39) being actuatable by an eccentric cam shaft (41).
11. A synchronizing mechanism according to claim 10, characterized in that the eccentric cam shaft (41) is mounted on a bearing brace (43) that extends backward from the front end of the counter-bearing extension arm (25).
12. A synchronizing mechanism according to claim 1, characterized in that the at least one counter-bearing extension arm (25) is executed as an adjusting shaft (51) that is rotation-driveable by an actuator (50) on the base carrier (1), said adjusting shaft (51) supporting on its rear-facing end a counter-bearing end stop (64) that can be adjusted spindle-like in the direction of the spring force of the helical compression spring (24) by a rotation of the shaft .
13. A synchronizing mechanism according to claim 12, characterized in that the actuator (50) incorporates an actuating shaft (52) disposed in the front region of the base carrier (1) perpendicular to the orientation of the adjusting shaft(s) (51), said actuating shaft (52) being coupled via a deflection gear (49) to the front end of the adjusting shaft(s) (51).
14. A synchronizing mechanism according to claim 13, characterized in that at least two adjusting shafts (51) are rotatably supported with their front end in a bearing yoke (65) disposed on a deflection gear shaft (49).
15. A synchronizing mechanism according to claim 12, characterized in that the deflection gear (49) incorporates a bevel gear (61) between the at least one adjusting shaft (51) and a gear shaft (57).

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