EP3738473A1

EP3738473A1 - Swivel device for a chair, a chair provided with a swivel device and chair operating method

Info

Publication number: EP3738473A1
Application number: EP20174541.1A
Authority: EP
Inventors: Geertjan VAN OLST
Original assignee: Prominent Holding BV
Current assignee: Prominent Holding BV
Priority date: 2019-05-13
Filing date: 2020-05-13
Publication date: 2020-11-18
Also published as: NL2023934B1

Abstract

The invention relates to a swivel device comprising:
- a base part to form or be connected to a chair base;
- a swivel part to form or be connected to a chair seat, said swivel part being rotatable relative to the base part about a substantially vertical rotation axis; and
- a locking element,
wherein the swivel part comprises a hole,
wherein the locking element is moveably arranged inside the hole to move in a direction parallel to the vertical rotation axis between a release position in which the swivel part is free to rotate relative to the base part and a lock position in which the angular orientation of the swivel part is substantially locked by engagement of both the swivel and base part with the locking element inside the hole.

Description

BACKGROUND OF THE INVENTION

The invention relates to a swivel device for a chair, a chair provided with such a swivel device, and a method for operating such a chair.
Applicant is producer of chairs that may include a so-called standup aid function in which the chair or part thereof is pivotable about a substantially horizontal axis to move the seat and thus the user upwards to help the user get out of the chair. However, when a user wants to get out of the chair using the standup aid function, the fact that the chair is also able to rotate about a substantially vertical axis as provided for by the swivel device is annoying and tiresome for the user.
In order to solve this problem, applicant currently uses an electric drive to operate a clamp to move into frictional engagement with a base part of the swivel device to lock the angular position of the seat about the vertical axis. However, this solution may have several drawbacks, including but not limited to:

the electric drive being an active member consuming power;
the electric drive and clamp taking up a lot of space;
the clamping action on the base part introducing damage and wear to the base part; and
the electric drive requiring additional control.

SUMMARY OF THE INVENTION

In view of the above it is an object of the invention to provide a chair of which the angular position of the seat about the vertical axis can be locked relative to the base while solving one or more of the abovementioned drawbacks.
To achieve the object of the invention, there is provided a swivel device for a chair, comprising:

a base part to form or be connected to a chair base;
a swivel part to form or be connected to a chair seat, said swivel part being rotatable relative to the base part about a substantially vertical rotation axis; and
a locking element,

An advantage of the swivel device according to the invention is that damage and wear to the base, if present to a notable degree, are not visible on the outside and thus the appearance of the swivel device is not adversely affected by the locking function.
A further advantage may be that providing the locking function inside the swivel device safes a lot of space compared to the prior art.
In an embodiment, the swivel part comprises an opening at an upper end thereof, wherein the hold extends downwards from said opening to the base part.
This allows the locking element to extend from the swivel part or to be accessible via the opening in the swivel part, which allows for passive control of the locking function without having to use a dedicated electric drive, thereby reducing the required control power and/or consumption of energy.
In an embodiment, the swivel device further comprises a spring urging the locking element towards the lock position. This aids in providing passive control of the locking function as for instance upwards movement of the seat attached to the swivel part may then automatically result in locking of the swivel device due to the spring action.
In an embodiment, the swivel device is configured such that the locking element can be moved towards the release position by applying a force to the locking element that is opposite and initially larger than a spring force applied by the spring to the locking element. Said force can originate from a weight from a chair, a person in the chair, or a combination thereof. However, it can alternatively of additionally originate from an actuator such as a separate drive or a drive responsible for the position or orientation of a seat of the chair. It is also envisaged that a magnetic actuator is provided that is configured to move the locking element towards the release position in an active or energized state and allows the spring to move the locking element towards the lock position in an inactive or deenergized state.
In an embodiment, the locking element comprises a top portion extending from or above the opening in the swivel part in at least the lock position. This allows the seat or a portion thereof to engage with the locking element to position the locking element in either the release position or the lock position.
In an embodiment, the locking element in the lock position is located at a larger distance from the base part than in the release position. In other words, during use of the swivel device in a chair standing on the ground, the locking element in the lock position is at a higher level above the ground than in the release position. This may correspond to the position of a seat and the required locking function, e.g. the seat in a lower position may correspond to the locking element being in the release position and the seat in an upper position, for instance to aid in standup, may correspond to the locking element being in the lock position.
However, alternatively, the locking element in the lock position is located at a smaller distance from the base part than in the release position. In other words, during use of the swivel device in a chair standing on the ground, the locking element in the release position is at a higher level above the ground than in the lock position. This may be advantageous when gravity on the lock element is used to urge the locking element towards the lock position as explained below. It may also correspond to the position of a seat and the required locking function as described for the alternative situation when a lever is used in between the seat and the locking element allowing to lift the locking element while moving the seat down.
In an embodiment, the engagement of the swivel part with the locking element is a form fitting engagement. Alternatively, the engagement is a frictional engagement.
In an embodiment, the engagement of the base part with the locking element is a form fitting engagement. Alternatively, the engagement is a frictional engagement.
For both engagements, the form fitting engagement is preferred as this is less prone to wear and damage. However, an advantage of the frictional engagement is that rotation is still possible when the applied friction is overcome without severely damaging the swivel device.
In an embodiment, the form fitting engagement is provided by a portion of the locking element having a polygonal cross-section that is able to at least partially mesh with a corresponding polygonal cross-section of the swivel part or the base part at least in the lock position.
In an embodiment, the form fitting engagement is provided by an internal gear meshing at least partially with an external gear at least in the lock position.
In an embodiment, in the release position, the swivel part is free to rotate relative to the base part due to disengagement between the swivel part and the locking element. Alternatively, or additionally, the swivel part is free to rotate relative to the base part due to disengagement between the base part and the locking element.
Hence, in an exemplary embodiment, there is a continuous engagement between the swivel part and the locking element in both the release position and the lock position, and thus in any intermediate position, while there is only engagement between the base part and the locking element in the lock position, and possibly in some intermediate positions close to the lock position. The reverse situation may also apply.
In an embodiment, the base part includes a bore to receive the swivel part, and wherein the locking element extends in the hole to below the swivel part in the bore to engage with the base part in at least the lock position.
In an embodiment, the spring is arranged in the bore between the base part and the locking element.
In an embodiment, the swivel device is configured to urge the locking element towards the lock position using gravity, in particular using gravitational forces acting on a weight of the locking element itself. In an embodiment, the swivel device is configured such that the locking element can be moved towards the release position by applying a force to the locking element that is opposite and initially larger than a gravitational force applied to the locking element. Said force can originate from a weight from a chair, e.g. using a lever, a person in the chair, or a combination thereof. However, it can alternatively of additionally originate from an actuator such as a separate drive or a drive responsible for the position or orientation of a seat of the chair. It is also envisaged that a magnetic actuator is provided that is configured to move the locking element towards the release position in an active state and allows gravity to pull the locking element towards the lock position in an inactive state.
In an embodiment, the swivel device comprises a lever that is pivotable about a pivot axis, wherein an end of the lever is attached to the locking element and the opposite end of the lever is engageable by a seat to move the locking element. The lever can in some embodiments be considered to be part of the locking element and/or may extend from the opening at the upper end of the swivel part.
In an embodiment, an actuator is provided as part of the swivel device to move the locking element between the lock position and the release position.
In an embodiment, the swivel part is rotatable about the rotation axis relative to the base part for at most 360 degrees. This may be advantageous to prevent tangling of wires caused by rotating the chair too much in the same direction.
The invention further relates to a chair comprising:

a base;
a seat assembly including a frame and a seat; and
a swivel device arranged between the base and the frame of the seat assembly,

An advantage of the chair according to the invention is that the position of the seat determines whether the locking element of the swivel device is in the release position or in the lock position, which provides passive control of the swivel device.
In an embodiment, the upper position of the seat corresponds to an empty seat with no user in the chair, while the lower position of the seat corresponds to a user being present in the seat, so that when there is no person sitting in the chair, the swivel device is locked and the seat assembly cannot rotate relative to the base, and when a person is sitting in the chair, the swivel device is released and rotation of the seat assembly relative to the base is allowed.
The seat assembly may for instance be provided with a spring urging the seat to the upper position while allowing the weight of a person to move the seat to the lower position.
In an embodiment, the upper position of the seat corresponds to a standup position while the lower position of the seat corresponds to a sitting position. Preferably, a first actuator is provided to position the seat.
In an embodiment, the chair includes arm rests connected to the seat of the seat assembly.
In an embodiment, the chair includes a back connected to the seat of the seat assembly, wherein the back is preferably pivotable relative to the seat between an upright position and a lying position. The angular orientation of the back relative to the seat may be adjustable by a second actuator provided between the seat and the back. The aformentioned arm rests may be alternatively or additionally be connected to the back.
In an embodiment, the chair includes a leg rest connected to the seat assembly for supporting the lower legs of a user. The leg rest may be moveable relative to the seat assembly between a relax position in which the leg rest is arranged to support the lower legs of a user, and a hidden position in which the leg rest is at least partially arranged below the seat assembly to allow a user to position both feet on the ground when sitting in the chair. Preferably, the leg rest is connected to both the seat and the frame using a linkage mechanism such that operating the first actuator also allows to position the leg rest relative to the frame of the seat assembly. However, a third actuator may be provided to operate the leg rest. Control of the first and third actuator may be such that when operating the first actuator, the leg rest is prevented from interfering with other parts of the chair.
In an embodiment, the chair includes a head rest, e.g. connected to the back. Preferably, the head rest is pivotable relative to the back. The head rest may be configured to be positioned manually, e.g. by overcoming a predetermined friction threshold, and/or using a fourth actuator.
In an embodiment, the swivel device is a swivel device according to the invention, wherein the base part is integral with or connected to the base, and wherein the swivel part is integral with or connected to the frame of the seat assembly. Any feature described above with respect to the swivel device according to the invention may be a feature of the swivel device of the chair according to the invention as will be apparent to the skilled person.
The invention yet also relates to a chair comprising:

In an embodiment, the configuration of the seat assembly and the swivel device is a passive configuration such that the seat includes a member to engage with the locking element of the swivel device such that in the lower position of the seat, the locking element of the swivel device is in the release position, and such that in the upper position of the seat, the locking element of the swivel device is in the lock position, as described above.
The abovementioned engagement between the member of the seat and the locking element may be a direct engagement between the member and the locking element, e.g. a top portion of the locking element, but may also be an indirect engagement, e.g. via a lever that is pivotable about a pivot axis, wherein an end of the lever is attached to the locking element and the opposite end of the lever is engageable by the member of the seat to move the locking element. When the lever is considered to be part of the locking element, the latter is also a direct engagement.
In an embodiment, the swivel device is a swivel device according to the invention.
In an embodiment, the configuration of the seat assembly and the swivel device is an active configuration such that an active component, e.g. an actuator or drive, is provided to move the locking element in the release position and/or the locking position.
In an embodiment, the swivel device may include a switch element and the seat includes a member to engage with the switch element, so that upon engagement between the member of the seat and the switch element, the active component is activated or inactivated to allow the locking element to move towards the release position.
The invention also relates to a method for using or operating a chair according to the invention, said method comprising the following steps:

a. providing the chair with the seat in the lower position; and
b. moving the seat to the upper position to aid a user in standing up from the chair.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in a non-limiting way with reference to the accompanying drawings in which like parts are indicated by like reference symbols, and in which:

Fig. 1: schematically depicts a perspective view of a chair according to an embodiment of the invention;
Fig. 2: schematically depicts a side view of the chair of Fig. 1;
Fig. 3: schematically depicts a swivel device of the chair of Fig. 1;
Fig. 4: schematically depicts a side view of the chair of Fig. 1 in a relax upright configuration;
Fig. 5: schematically depicts a perspective view of the chair of Fig. 1 in the relax upright configuration;
Fig. 6: schematically depicts a side view of the chair of Fig. 1 in a relax lying configuration;
Fig. 7: schematically depicts a side view of the chair of Fig. 1 in a stand-up configuration;
Fig. 8: schematically depicts a cross sectional view of the swivel device of Fig. 3 in a lock position;
Fig. 9: schematically depicts a perspective cross sectional view of the swivel device of Fig. 3 in the lock position;
Fig. 10: schematically depicts a perspective cross sectional view of the swivel device of Fig. 3 in a release position;
Fig. 11: schematically depicts a cross sectional view of the swivel device of Fig. 3 in the release position;
Fig. 12: schematically depicts the perspective cross sectional view of Fig. 10 with the swivel part being rotated relative to the base part;
Fig. 13: schematically depicts a perspective view of the chair of Fig. 1 with the seat in a first intermediate position and the swivel device in the lock position;
Fig. 14: schematically depicts a perspective view of the chair of Fig. 1 with the seat in a second intermediate position and the swivel device in the lock position;
Fig. 15: schematically depicts a perspective view of the chair of Fig. 1 with the swivel device in the release position
Fig. 16: schematically depicts an exploded view of a swivel device according to another embodiment of the invention;
Fig. 17: schematically depicts a perspective cross sectional view of the swivel device of Fig. 16 in a release position;
Fig. 18: schematically depicts a perspective cross sectional view of the swivel device of Fig. 16 in a lock position;
Fig. 19: schematically depicts a perspective cross sectional view of a swivel device according to a further embodiment of the invention;
Fig. 20: schematically depicts a cross sectional view of a detail of a swivel device according to another embodiment of the invention with a locking element in the lock position; and
Fig. 21: schematically depicts the swivel device of Fig. 20 with the locking element in the release position.

DETAILED DESCRIPTION OF THE INVENTION

Figs. 1 and 2 schematically depict a chair 1 according to an embodiment of the invention in which Fig. 1 depicts a perspective view and Fig. 2 depicts a side view.
The chair 1 includes a base 10, a swivel device 20, a seat assembly 30, arm rests 40, 41, a back 50, a leg rest 60 and a head rest 70.
The base 10 of the chair 1 is configured to support the other parts of the chair from the ground and is in this embodiment embodied as four legs 11 extending in different directions from a central member 12 to provide a stable support. However, the base 10 may also be formed as a disc or any other shape as is known in the art.
The swivel device 20, which is shown in isolation in Fig. 3, includes a base part 21 and a swivel part 22 that is rotatable relative to the base part 21 about a rotation axis 23 in use extending substantially vertically as shown in Fig. 2 and allowing the upper part of the chair 1 to rotate about the rotation axis 23.
In the embodiment of Figs. 1-3, the base part 21 includes a lower portion 21a and an upper portion 21b. The lower portion 21a is configured to be received in the central member 12 of the base 10 to connect the swivel device 20 to the base 10. To this end, the lower portion 21a may have a downwardly tapering, e.g. a conical, shape to be received in a matching opening (not shown) in the central member 12. The shape of the lower portion 21a and the matching opening in the central member 12 may be such that the connection obtained between the swivel device 20 and the base 10 is based on clamping and/or frictional forces.
It is explicitly noted here that although the swivel device 20 can be separated from the base 10 in this embodiment, the invention also relates to an embodiment in which the swivel device 20 is integral with the base 10, so that the base part 21 forms part of the base 10 or the base 10 forms part of the base part 21.
The swivel part 22 is configured to be connected to a frame 31 of the seat assembly 30. In this embodiment, the swivel part 22 tapers upwardly, e.g. has a conical shape, similar to the lower portion 21a of the base part 21, to be received in a matching opening (not shown) in the frame 31 of the seat assembly 30. The shape of the swivel part 22 and the matching opening in the frame 31 may be such that the connection obtained between the swivel device 20 and the seat assembly 30 is based on clamping and/or frictional forces.
Although clamping and/or frictional connections are described for the shown embodiment, it will be apparent to the skilled person that other connections may also be used. Further, the swivel device 20 may be integral with the frame 31, so that swivel part 22 forms part of the frame 31 or the frame 31 forms part of the swivel part 22.
An advantage of the swivel device 20 being separable from the base 10 and the seat assembly 30 is that the swivel device 20 can easily be replaced, e.g. in case of malfunction or extensive wear. The possibility to replace the swivel device may also allow to easily adapt the height of the chair 1, i.e. a height of the seat assembly 30, to a different user.
The swivel device 20 sets a height H between the base 10 and the seat assembly 30, which height H is mainly defined by the upper portion 21b of the base part 21 of the swivel device 20. Different swivel devices 20 with different heights H can easily be manufactured and used in chairs 1 to optimize the height of the chair 1 to the user.
The seat assembly 30 comprises the frame 31 that is connected to the swivel device and a seat 32. The seat 32, which provides the supporting surface for a user to sit on, is moveable relative to the frame 31. To position the seat 32 relative to the frame 31, a first actuator 33 is provided in the seat assembly 30.
The arm rests 40, 41 are connected to the seat 32 to move along with the seat 32 when positioned by the first actuator 33. The same applies to the back 50. Although the back 50 can have a fixed position or semi-fixed position relative to the seat 32, the back 50 is pivotable relative to the seat 32 about a pivot axis 51. The angular orientation of the back 50 relative to the seat 32 is adjusted using a second actuator 52 provided between the seat 32 and the back 50.
The leg rest 60 is connected to both the seat 32 and the frame 31 using a linkage mechanism 61 such that operating the first actuator 33 also allows positioning of the leg rest 60 along with the seat 32 relative to the frame 31.
The head rest 70 is connected to an upper end of the back 50 and is pivotable about a pivot axis 71 in this embodiment. In this embodiment, the angular orientation of the head rest 70 has to be set manually relative to the back, e.g. by overcoming a predetermined friction threshold between head rest 70 and back 50, which friction threshold keeps the head rest 70 in place relative to the back 50 after setting the angular orientation. Alternatively, or additionally, a fourth actuator (not shown) can be used to set the angular orientation of the head rest 70 relative to the back 50.
To illustrate the moveability of the seat 32, the back 50, and the leg rest 60, reference is made to Figs. 4-7, in which Fig. 4 depicts a side view of the chair 1 in a relax upright configuration, Fig. 5 depicts a perspective view of the chair 1 in the relax upright configuration, Fig. 6 depicts a side view of the chair 1 in a relax lying configuration and Fig. 7 depicts a side view of the chair 1 in a standup upright configuration. The terms "relax" and "standup" refer to two extreme positions defined by the first actuator 33, while the terms "upright" and "lying" refer to two extremes defined by the second actuator 52.
The configuration shown in Figs. 1 and 2 is referred to as the sitting upright configuration in which the leg rest 60 is positioned below the seat 32 to be moved out of the way and the back 50 is substantially perpendicular to the supporting surface of the seat 32. The term "sitting" thus refers to a position defined by the first actuator 33 in between the "relax" and "standup" positions. The leg rest 60 is not intended to be used in the sitting upright configuration so that a user is able to position its feet on the ground with the lower legs making an angle of substantially 90 degrees relative to the upper legs.
In the sitting upright configuration, the back 50 may be substantially parallel to the vertical and the seat 32 may be substantially parallel to the horizontal, but for providing more comfort, the back 50 and seat 32 may be tilted backwards relative to this orientation as shown for the embodiment in Figs. 1 and 2. The angle α (see Fig. 2) between the back 50 and the vertical may for instance be in the range of 0 - 20 degrees.
Appropriate control of the first actuator 33 may move the leg rest 60 into the position as shown in Figs. 4 and 5 by rotating in a direction R1 as shown in Fig. 2. In the configuration as shown in Figs. 4 and 5, the leg rest 60 has moved to a substantially horizontal orientation and has extended in a direction D1 away from the seat 32 thereby allowing to support the lower legs or feet of a user in the chair 1. It is noted that the orientation of the back 50 hasn't changed relative to the seat 32, but that movement of the leg rest 60 to the relax upright configuration may result in a tilting backwards of the seat 32 and thus also a tilting backwards of the back 50. The tilting backwards may be in the order of 0-10 degrees, preferably 2-5 degrees. However, as the orientation of the back 50 hasn't changed relative to the seat 32, this configuration will thus be referred to as the relax upright configuration.
Starting from the relax upright configuration shown in Figs. 4 and 5, appropriate control of the second actuator 52 may move the back 50 to a lying position as shown in Fig. 6. The angle β between back 50 and seat 32 that was about 90 degrees in the upright position shown in Figs. 1, 2, 4 and 5 has now been increased to for instance 135 degrees. The configuration as shown in Fig. 6 will thus be referred to as the relax lying configuration.
Although not shown, it will be apparent to the skilled person that appropriate control of the second actuator starting from the sitting upright configuration may increase the angle β in a similar manner but now with the leg rest being kept below the seat 32. This configuration will be referred to as the sitting lying configuration.
Referring now to Fig. 7, it can be clearly seen in this figure that the frame 31 includes a four-bar linkage comprised of stationary part 31a that is connected to the swivel part of the swivel device, and linkage bars 31b - 31d. When the first actuator is operated to move the leg rest 60 from the sitting upright configuration to the relax upright configuration as described above, the first actuator 33 applies forces urging the linkage bars 31b - 31d downwards thereby tilting the seat 32 backwards as the seat 32 mainly follows the orientation of linkage bar 31c. However, the seat 32 is prevented from tilting backwards due to downwards movement of the linkage bar 31c as a member 34 engages with the swivel device 20. Hence, the resulting movement is limited to movement of the leg rest 60 and possibly slight tilting backwards due to an upwards movement of the seat 32 at the leg rest side, i.e. the front side, as already mentioned above.
Moving the leg rest 60 from the relax upright configuration to the sitting upright configuration requires an opposite operation of the first actuator 33. In principle, control of the first actuator towards the sitting upright configuration may result in two movements, namely moving the leg rest to below the seat 32 and urging the linkage bars 31b - 31d upwards. However, the weight of the seat 32 and all components connected thereto, possibly including the weight of a user in the chair 1 will cause movement of the leg rest 60 only. Upon reaching the sitting upright position with the leg rest 60 below the seat 32, the leg rest 60 will be prevented from further movement relative to the seat 32 causing the linkage bars 31b - 31d and thus the seat 32 and all components connected thereto to move upwards until the configuration as shown in Fig. 7 is reached. Not only has the seat 32 been moved upwards, it also has been tilted forwards thereby aiding a person to stand up from the chair 1. The configuration as shown in Fig. 7 will thus be referred to as standup upright configuration.
When moving the chair 1 to the standup upright configuration to aid a user in standing up from the chair1, it is preferred that the seat 32 is not able to rotate about the rotation axis 23 allowing a user to stand up stably. Below, Figs. 8-15 will be used to explain how the seat 32 of chair 1 of Figs. 1-7 is prevented from rotating.
Fig. 8 schematically depicts a cross-sectional view of the swivel device 20 of Fig. 3 and Fig. 9 schematically depicts a perspective cross-sectional view of the swivel device 20 of Fig. 8. Clearly shown in Fig. 8 are the earlier described base part 21 with the lower portion 21a and the upper portion 21b, and the swivel part 22 that is rotatable relative to the base part 21 about the rotation axis 23.
In the cross-sectional view of Fig. 8, it can clearly be seen that the base part 21 includes a through hole 24 extending from an opening at an upper end thereof towards an opening at an opposite lower end thereof.
The swivel part 22 is received inside the hole 24 and extends over the height of the hole 24 corresponding to the upper portion 21b of the base part 21. At the opening at the upper end of the base part 21, a first bearing 25a is provided between the swivel part 22 and the base part 21. At the lower end of the swivel part 22, which is substantially at the transition between upper portion 21b and lower portion 21a of the base part 21, a second bearing 25b is provided between the swivel part 22 and the base part 21.
The hole 24 is wider in the lower portion 21a of the base part 21 than in the upper portion 21b of the base part 21 forming a shoulder 21c to be engaged by the second bearing 25b and allowing a fixation member 26 to be connected to the lower end of the swivel part 22 to engage with the second bearing 25b which prevents the swivel part from being pulled upwards out of the hole 24.
The swivel device 20 further comprises a locking element 27 having a lower portion 27a, an upper portion 27c and a central portion 27b in between the lower 27a and the upper portion 27c.
The swivel part 22 has a through hole 22a extending from an upper end thereof to the lower end thereof and configured to receive the locking element 27. The swivel part 22 comprises an end member 22b with a square shaped opening 22c. The upper portion 27c of the locking element 27 has a square shaped cross-section that matches the square shaped opening 22c of the end member 22b thereby providing a rotation lock between locking element 27 and the swivel part 22 due to the form fitting engagement between the upper portion 27c of the locking element 27 and the end member 22b of the swivel part 22 while allowing the locking element 27 to move in a direction parallel to the rotation axis 23 relative to the end member 22b of the swivel part 22.
The lower portion 27a of the locking element 27 is provided below the swivel part 22 in the wider portion of the hole 24 and has an inverted cup shape with an external gear 27d at a lower edge thereof. The base part 21 at the wider portion of hole 24 comprises an inner gear 21d configured to mesh with the external gear 27d of the locking element 27 as shown in Figs. 8 and 9. Hence, due to the mesh between the internal gear 21d and the external gear 27d, the locking element 27 is rotationally locked relative to the base part 21. Combined with the rotation lock between the locking element 27 and the swivel part 22, this means that the swivel part 22 cannot rotate relative to the base part 21 in the position of the locking element as shown in Figs. 8 and 9. This position of the locking element 27 will be referred to as the lock position.
The lower portion 27a of the locking element 27 has an inverted cup shape with a cavity 27e configured to receive an upper end of a spring 28. The opening in the lower portion 21a of the base part 21 is closed off by a cap 29 having a cup shape with a cavity 29a to receive a lower end of the spring 28. The spring 28 is a compression spring urging the locking element towards the lock position in engagement with the lower end of the swivel part 22.
The swivel device 20 further comprises a spacer 25c between the swivel part 22 and the first bearing 25a providing sufficient space between frame 31 and the base part 21 when the frame 31 is connected to the swivel part 22.
Due to the engagement of both the swivel part 22 and the base part 21 with the locking element 27 inside the hole 22a and hole 24, the locking function is provided without requiring a lot of space relative to a swivel device without having this locking function. Further, an advantage is that engagement takes place inside the swivel device and thus damage on the outside of the swivel device is prevented. Last but not least, the locking function may be provided without requiring active components and thus without requiring control or power.
The opening 22c at the upper end of the swivel part 22 through which the upper portion 27c of the locking element 27 extends allows to operate the locking element. In this embodiment, operating the locking element 27 may be allowed by operating the upper portion 27c extending through the opening 22c, but alternatively, or additionally, the locking element 27 may not extend beyond the opening 22c, but the opening 22c allows to operate the upper portion of the locking element via the opening 22c.
Figs. 10 and 11 depict the locking element 27 in a release position in which the locking element has been moved downwards relative to the lock position as shown in Figs. 8 and 9. Fig. 10 is a perspective cross-sectional view corresponding to the view of Fig. 9 while Fig. 11 is a cross-sectional view corresponding to the view of Fig. 8.
In the release position of the locking element 27, the external gear 27d is not in engagement anymore with the internal gear 21d thereby releasing one form fitting engagement between the base part 21 and the swivel part 22 thereby allowing the swivel part 22 to be free to rotate relative to the base part about the rotation axis 23. To illustrate this, Fig. 12 depicts the same view as Fig. 10 but with the swivel part 22 rotated relative to the base part 21 thereby clearly showing the teeth of the external gear 27d and the internal gear 21d.
Moving the locking element 27 from the lock position to the release position is done using the member 34 on the seat 32 as will be explained below by reference to Figs. 7 and 13-15.
Fig. 7 depicts the chair 1 in the standup upright configuration in which the seat 32 has been raised and tilter forwards relative to the frame 31. This means that member 34 is released from the swivel device 20. Fig. 15 depicts a perspective view of the chair 1 in the sitting upright configuration of Figs. 1 and 2, but now from the back clearly depicting the engagement between the member 34 and the swivel device 20. Figs. 13 and 14 depict similar views as Fig. 15 of the chair 1 in different intermediate positions between the standup upright configuration in Fig. 7 and the sitting upright configuration in Fig. 15.
In Figs. 13, 14 and 7, the member 34 is not in engagement with the locking element 27, so that the spring 28 in the swivel device 20 urges the locking element 27 to the lock position. When the teeth of the internal gear 21d and the external gear 27d are able to mesh, the locking element 27 will actually move towards the lock position thereby locking the angular rotation of the swivel part and all components connected thereto relative to the base part. The upper portion 27c of the locking element 27 thus protrudes from the swivel part as can be clearly seen in Figs. 13 and 14. If initially, the teeth do no mesh and thus the locking element is prevented from moving to the lock position, an advantage of the relatively large number of teeth on the inner and external gears is that it only requires a small rotation of the seat relative to the base to reach a position in which the gears are able to mesh and thus the locking element is able to move to the lock position due to the spring force applied to the locking element.
When the first actuator 33 is operated to move the seat 32 to the sitting upright position shown in Figs. 1, 2 and 15, member 34 will come in to engagement with the locking element 27, i.e. the upper portion 27c of the locking element 27, causing the locking element to move to the release position allowing to rotate the swivel part and all components connected thereto relative to the base part.
Although in the above described embodiment, movement of the seat is controlled using an actuator, it is also possible that the chair has a moveable seat 32 that is moveable between a position as depicted in Fig. 13 or 14 and the position as depicted in Fig. 15 and a spring is provided urging the seat towards the position as depicted in Fig. 13 or 14 so that when there is no user in the chair, i.e. the seat is empty, the seat is in the position as depicted in Fig. 13 or 14 and thus the locking element is in the lock position. When a user is lowering itself to sit in the chair, the weight of the user will move the seat against the spring force towards the position as depicted in Fig. 15 thereby moving the locking element to the release position. In this way, a passive control of the swivel device is provided as an alternative or addition to the above described active control. Hence, the swivel device according to the invention can also be used in a chair which does not have a standup aid function, but combinations are of course also possible.
Fig. 16 schematically depicts an exploded view of a swivel device 20 according to another embodiment of the invention. The swivel device 20 includes a base part 21 and a swivel part 22 that is rotatable relative to the base part 21 about a rotation axis 23, said rotation axis 23 in use extending substantially vertically and allowing a seat, i.e. an upper part of a chair, to rotate about the rotation axis 23.
In the embodiment of Fig. 16, the base part 21 includes a lower portion 21a and an upper portion 21b. The lower portion 21a is configured to be received in a central member of a base of a chair to connect the swivel device 20 to the base. To this end, the lower portion 21a may have a downwardly tapering, e.g. a conical, shape to be received in a matching opening in the central member. The shape of the lower portion 21a and the matching opening in the central member may be such that the connection obtained between the swivel device 20 and the base is based on clamping and/or frictional forces.
The swivel part 22 is configured to be connected to a frame of a seat assembly of a chair.
Fig. 17 and 18 schematically depict perspective cross-sectional views of the swivel device 20 of Fig. 16 in a release position and a lock position, respectively. In the below description, reference will be made to the Figs. 16-18.
Base part 21 includes a through hole 24 extending from an opening at an upper end thereof towards an opening at an opposite end thereof.
The swivel part 22 is received inside the hole 24. At the opening at the upper end of the base part 21, a first bearing 25a is provided between the swivel part 22 and the base part 21. At the lower end of the swivel part 22, a second bearing 25b is provided between the swivel part 22 and the base part 21.
The hole 24 is wider in the lower portion 21a of the base part 21 than in the upper portion 21b of the base part 21 forming a shoulder 21c to be engaged by the second bearing 25b and allowing a fixation member 26 to be connected to the lower end of the swivel part 22 to engage with the second bearing 25b which prevents the swivel part from being pulled upwards out of the hole 24 and/or prevents the second bearing 25b from moving downwards.
The swivel device 20 further comprises a locking element 27 having a lower portion 27a, an upper portion 27c and a central portion 27b in between the lower 27a and the upper portion 27c.
The swivel part 22 has a through hole 22a extending from an upper end thereof to the lower end thereof and configured to receive the locking element 27. The swivel part 22 comprises an end 22b with a square shaped opening 22c. The upper portion 27c of the locking element 27 has a square shaped cross-section that matches the square shaped opening 22c of the end member 22b thereby providing a rotation lock between locking element 27 and the swivel part 22 due to the form fitting engagement between the upper portion 27c of the locking element 27 and the end 22b of the swivel part 22 while allowing the locking element 27 to move in a direction parallel to the rotation axis 23 relative to the end 22b of the swivel part 22.
The lower portion 27a of the locking element 27 is provided below the swivel part 22 in the wider portion of the hole 24. An external gear 27d is attached to the lower portion 27a of the locking element 27 using a washer 27f and a bolt 27g received in a threaded hole 27h.
The lower portion 27a includes an extension 27i that is substantially rectangularly shaped and matches a shape of opening 27j in the external gear 27d, thereby providing a form fitting engagement between external gear 27d and lower portion 27a.
The base part 21 at the wider portion of hole 24 comprises an inner gear 21d configured to mesh with the external gear 27d of the locking element 27 as shown in Fig. 18. Hence, due to the mesh between the internal gear 21d and the external gear 27d, the locking element 27 is rotationally locked relative to the base part 21. Combined with the rotation lock between the locking element 27 and the swivel part 22, this means that the swivel part 22 cannot rotate relative to the base part 21 in the position of the locking element as shown in Fig. 18. This position of the locking element 27 will be referred to as the lock position.
The opening in the lower portion 21a of the base part 21 is closed off by a cap 29 having a cup shape with a cavity 29a to receive a lower end of a spring 28. The upper end of the spring 28 engages with the external gear 27d. The spring 28 is a compression spring urging the locking element towards the lock position in engagement with the lower end of the swivel part 22. The cap 29 includes an outer thread 29b that is configured to mate with an inner thread 21f in the lower portion 21a of the base part 21 to withstand the spring force.
The swivel device 20 further comprises a spacer 25c between the swivel part 22 and the first bearing 25a providing sufficient space between frame 31 and the base part 21 when the frame 31 is connected to the swivel part 22.
The spacer 25c in this embodiment is connected such that the spacer 25c rotates along with the swivel part 22. Extending downwards from the spacer 25c is a pin 25d that is received in a circular groove 21e provided in an upper surface of the base part 21. The groove 21e includes a wall 21f that blocks passage of the pin 25d, so that the swivel part 22 can only rotate from an angular orientation at one side of the wall 21f to another angular orientation at an opposite side of the wall 21f thereby preventing a rotation of more than 360 degrees. In other words, the circular-shaped groove 21e spans over an angle of at most 360 degrees, e.g. 350 degrees. This may be advantageous when wiring is used to connect equipment of the chair to mains or other equipment. When rotation of the chair is limited, the chance of the wiring getting tangled or damages is reduced.
Due to the engagement of both the swivel part 22 and the base part 21 with the locking element 27 inside the hole 22a and hole 24, the locking function is provided without requiring a lot of space relative to a swivel device without having this locking function. Further, an advantage is that engagement takes place inside the swivel device and thus damage on the outside of the swivel device is prevented. Last but not least, the locking function may be provided without requiring active components and thus without requiring control or power.
The opening 22c at the upper end of the swivel part 22 through which the upper portion 27c of the locking element 27 extends allows to operate the locking element. In this embodiment, operating the locking element 27 may be allowed by operating the upper portion 27c extending through the opening 22c, but alternatively, or additionally, the locking element 27 may not extend beyond the opening 22c, but the opening 22c allows to operate the upper portion of the locking element via the opening 22c.
Pushing the locking element 27 downwards, e.g. using the seat of a chair, will move the locking element 27 in a direction opposite the spring force towards a release position as shown in Fig. 17 in which the external gear 27d is no longer mating, i.e. in engagement, with the inner gear 21d allowing the locking element 27 and thus the swivel device 22 to rotate freely about rotation axis 23,
Fig. 19 schematically depicts a perspective cross-sectional view of a swivel device 20 according to yet another embodiment of the invention. However, swivel device 20 shows many similarities with the embodiment described in relation to Figs. 16-18 and thus in the below description emphasis will be given to the differences. For the similarities, reference is made to the above description in relation to Figs. 16-18.
The embodiment of Fig. 19 has many similarities with the embodiment of Figs. 16-18 as they may be part of the same product family and thus may be used with the same chairs. The main difference between the two embodiments is the height of the swivel device. Both devices are able to be arranged between similar bases and seat assemblies, but a height H of the upper portion of the base part 21 of the swivel device 20 in the embodiment of Fig. 19 is larger than a corresponding height H in the embodiment of Figs. 16-18, thereby allowing to position the seat assembly at a larger distance from the ground using the swivel device 20 of Fig. 19.
The design of the swivel device 20 of Fig. 19 is preferably such that all parts except the base part 21 are equal to the corresponding parts of the swivel device 20 of Figs. 16-18, thereby providing a modular design that is easy to fabricate. To allow the use of the same parts, the inner thread 21f is positioned at the same distance from the opening of hole 24 at the upper end thereof and the opposite opening at the lower end of hole 24 is large enough to allow the insertion of cap 29.
Hence, by replacing the base part 21 only, the swivel device 20 can be quickly adapted to different heights.
In the above embodiment, the locking element 27 in the lock position is at a larger distance above the ground than in the release position and the spring 28 is used to move the locking element 27 from the release position to the lock position. However, other embodiments can also be envisaged. An example thereof is provided in Figs. 20 and 21 which does not require the use of a spring, but merely uses gravity to move the locking element from the release position to the lock position.
Figs. 20 and 21 only depict a cross-sectional view of an upper portion of a swivel part 22 and a locking element 27 of a swivel device 20 according to another embodiment of the invention.
The swivel part 22 is provided with an opening 22c at an upper end thereof and a hole 22a extending downwards from said opening 22c to a base part of the swivel device 20.
The locking element 27 is arranged inside the hold 22a and is moveable in a direction parallel to rotation axis 23 of the swivel part 22. A lever 120 is arranged in the opening 22c with a first free end 120a extending from the opening 22c and a second free end 120b extending in the hole 22a. The second free end 120b is pivotably connected to the locking element 27 and the lever 120 is pivotably connected in the opening 22c to the swivel part 22.
Considering the swivel device 20 of Figs. 20 and 21 to be part of a chair according to an embodiment of the invention, the chair, more in particular a seat assembly thereof may include a frame and a seat, wherein the frame is to be connected to the swivel part 22 of the swivel device, and the seat may include a member to engage with the lever 120, so that when the seat is in a lower position, said member engages with the lever and the actuator force or the gravitational force resulting therefrom will put the lever 120 in the position of Fig. 21 and when the seat is in an upper position, said member is disengaged from the lever 120 and gravity will pull the locking element 27 downwards towards the position as shown in Fig. 20.
Hence, in Fig. 20, the locking element 27 is in the lock position and in Fig. 21, the locking element 27 is in the release position.

Claims

A swivel device for a chair comprising:
- a base part to form or be connected to a chair base;

- a swivel part to form or be connected to a chair seat, said swivel part being rotatable relative to the base part about a substantially vertical rotation axis; and

- a locking element,
wherein the swivel part comprises a hole,
wherein the locking element is moveably arranged inside the hole to move in a direction parallel to the vertical rotation axis between a release position in which the swivel part is free to rotate relative to the base part and a lock position in which the angular orientation of the swivel part relative to the base part about the vertical rotation axis is substantially locked by engagement of both the swivel part and the base part with the locking element inside the hole.
A swivel device according to claim 1, wherein the swivel part comprises an opening at an upper end thereof, and wherein the hold extends downwards from said opening to the base part, wherein preferably the locking element comprises a top portion extending from or above the opening in the swivel part in at least the lock position.
A swivel device according to claim 1 or 2, further comprising a spring urging the locking element towards the lock position.
A swivel device according to any of claims 1-3, wherein the locking element in the lock position is located at a larger distance from the base part than in the release position.
A swivel device according to any of claims 1-4, wherein the engagement of the swivel part with the locking element and/or the engagement of the base part with the locking element is a form fitting engagement, wherein preferably the form fitting engagement is provided by a portion of the locking element having a polygonal cross-section that is able to at least partially mesh with a corresponding polygonal cross-section of a portion of the swivel part or the base part at least in the lock position, and/or wherein preferably the form fitting engagement is provided by an internal gear meshing with an external gear in the lock position.
A swivel device according to any of claims 1-4, wherein the engagement of the swivel part with the locking element and/or the engagement of the base part with the locking element is a frictional engagement.
A swivel device according to any of claims 1-6, wherein, in the release position, the swivel part is free to rotate relative to the base part due to disengagement between the swivel part and the locking element, or wherein, in the release position, the swivel part is free to rotate relative to the base part due to disengagement between the base part and the locking element.
A swivel device according to any of the claims 1-7, wherein the base part includes a bore to receive the swivel part, and wherein the locking element extends in the hole to below the swivel part in the bore to engage with the base part in at least the lock position, wherein preferably a spring is arranged in the bore between the base part and the locking element.
A swivel device according to claim 1, wherein the swivel device is configured to urge the locking element towards the lock position using gravity, and wherein preferably the swivel device comprises a lever that is pivotable about a pivot axis, wherein an end of the lever is attached to the locking element and the opposite end of the lever is engageable by a seat to move the locking element.
A swivel device according to claim 1, wherein an actuator is provided to move the locking element between the lock position and the release position.
A swivel device according to any of claims 1-10, wherein the swivel part is rotatable about the rotation axis relative to the base part for at most 360 degrees.
A chair comprising:
- a base;

- a seat assembly including a frame and a seat;

- a swivel device arranged between the base and the frame of the seat assembly,
wherein the swivel device includes a locking element that is moveable between a release position in which the swivel device is free to swivel and a lock position in which the swivel device is locked by the locking element
wherein the seat is moveable between a lower position and an upper position relative to the frame of the seat assembly,
and wherein the seat assembly and the swivel device are configured such that in the lower position of the seat, the locking element of the swivel device is in the release position, and such that in the upper position of the seat, the locking element of the swivel device is in the lock position, wherein preferably the seat includes a member to engage with the locking element of the swivel device such that in the lower position of the seat, the locking element of the swivel device is in the release position, and such that in the upper position of the seat, the locking element of the swivel device is in the lock position.
A chair according to claim 12, wherein the swivel device is a swivel device according to any of the claims 1-11, wherein the base part is integral with or connected to the base, and wherein the swivel part is integral with or connected to the frame of the seat assembly.
A chair according to claim 12 or 13, wherein the lower position of the seat corresponds to a sitting position, wherein the upper position of the seat corresponds to a standup position, and wherein preferably a first actuator is provided to position the seat.
A chair according to claim 12, further including an active component, e.g. an actuator or drive, to move the locking element in the release position and/or the locking position, wherein preferably the swivel device includes a switch element and the seat includes a member to engage with the switch element, so that upon engagement between the member of the seat and the switch element, the active component is activated or inactivated to allow the locking element to move towards the release position.
A method for using or operating a chair according to any of claims 12-15, comprising the following steps:
a. providing the chair with the seat in the lower position; and

b. moving the seat to the upper position to aid a user in standing up from the chair.