CENTRAL UNIT FOR A CHAIR

CROSS-REFERENCE TO RELATED APPLICATIONS

Applicant claims priority under 35 U.S.C. § 119 of European Application No. 23218090.1 filed Dec. 19, 2023, the disclosure of which is incorporated by reference.

BACKGROUND OF THE INVENTION
1. Field of the Invention

The invention relates to a central unit for a chair, in particular an office chair.

The central component of office chairs is usually a mechanical component which is predominantly made of metal. The mechanical component allows a base to be fastened thereon. A seat and backrest are also arranged on the central component. The central component often ensures that the backrest and seat can be moved synchronously with one another.

In the office chair sector as well, manufacturers are being asked to meet increasingly stringent requirements in terms of sustainability and recyclability. A conventional office chair comprises a large number of components that have to be laboriously separated for recycling, and some of them are not at all recyclable.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide a central unit for a chair that is simple in design and recyclable.

According to the invention, this object is achieved by a central unit for a chair, in particular an office chair, having a multi-joint body that comprises a seat part for a seat, a backrest part for a backrest, a support part for a support of a base and a front part arranged between the seat part and the support part. The multi-joint body comprises at least three joints which in each case connect two of the specified parts in an articulated manner. Such a central unit can preferably be made from a single material, for example in an injection molding process. If the central unit is only made of one material, it can simply be recycled. The at least three joints can be designed in the same way, such that different joints do not have to be provided for the assembly of the central unit.

Particular advantages arise if at least one, in particular at least three, preferably four of the joints are designed as a solid-body joint. A solid-body joint is a region of a component that allows relative movement (rotation) between two rigid body regions by means of bending. A solid-body joint is based on the principle of elasticity. The function of a joint is achieved by a region that comprises a lower bending stiffness than two adjacent regions. The reduced bending stiffness can be achieved by locally reducing the material thickness. Solid-body joints are often also referred to as film joints, film hinges or flat joints. They are band hinges and have no mechanical parts. Thus, solid-body joints can eliminate the need for mechanical parts that subsequently do not need to be recycled.

In principle, it is conceivable to provide the solid-body joints as separate components and in each case to connect them to two of the seat part, backrest part, support part and front part. However, particular advantages arise if the solid-body joints are formed in one piece, in particular in a material-locking manner, with the parts that they connect. The solid-body joints and the associated parts can be manufactured in an injection molding process, for example. As a result, the need for subsequent assembly work is subsequently eliminated.

Preferably, at least the seat part, the backrest part and the support part are designed to be rigid and the solid-body joints are designed to be flexible, in particular elastic. The seat part, backrest part, support part and/or front part are designed to be stiffer than the solid-body joints. The solid-body joints preferably have a lower material thickness than the seat part, support part, front part and/or backrest part.

Particular advantages arise if the multi-joint body is designed as a single piece. Thus, the multi-joint body can be manufactured in one piece, for example in an injection molding process. The seat part and/or backrest part can be designed in such a way that a seat, for example a seat shell, and a backrest can be fastened to the seat part or backrest part. However, it is also conceivable to design the seat part and the backrest part in such a way that they already form the seat and the backrest. If required, a seat cushion or backrest cushion can be arranged thereon. In this way, an (office) chair, with very few separate components that can be easily detached from one another and recycled at the end of the normal service life of the chair, arises.

If the multi-joint body is made of plastics material, in particular glass fiber-reinforced plastics material, preferably glass fiber-reinforced polyamide, it can be manufactured particularly easily in an injection molding process. Such a multi-joint body can also be easily recycled.

According to one embodiment of the invention, it can be provided that exactly one of the joints is designed as a hinge with a rotation pin. The multi-joint body can be injection-molded with receptacles for the rotation pin. The receptacles can subsequently be connected to one another by the rotation pin in order to form a joint. The other joints of the central unit can be designed as solid-body joints.

According to a further embodiment of the invention, it can be provided that the front part is designed to be flexurally elastic. The other parts, in particular the seat part, backrest part and support part, can be designed to be rigid or at least more rigid. The front part can comprise a joint, in particular a solid-body joint, only at one end. As a result, the number of joints can be reduced. In particular, such a multi-joint body can only comprise three joints. The three joints can be designed as solid-body joints. In particular, with this embodiment, the front part can have a lower material thickness than the support part, the backrest part and the seat part, but a greater material thickness than the solid-body joints.

In order to provide sufficient resistance for the tilting back of the backrest, it can be advantageous to arrange a spring arrangement between the seat part and the support part. The spring arrangement can, for example, comprise one or more spring elements which can be designed in the form of leaf springs. The spring arrangement can be manufactured together with the rest of the multi-joint body in an injection molding process. At least one spring element of the spring arrangement can be formed in one piece, in particular in a material-locking manner, with the seat part and the support part.

In order to be able to adjust the central unit to different user weights, the spring arrangement can comprise at least one spring element that can be activated and deactivated or attached to the multi-joint body. Such a spring element can, for example, be formed in one piece with the seat part at one end. The other end of the spring element can be pivotably arranged on the support part. This pivot action can be blocked by a slider. In the blocked position, the spring element exerts its spring effect, while it is deactivated in the position released by the slider. Alternatively, several spring elements may be provided. The spring elements may be identical and according to the required spring force one or several spring elements may be attached to the multi-joint body. Furthermore, spring elements having different width, different thickness and/or being made of different materials may be provided. The spring element(s) needed for a desired spring force may be installed on the multi-joint body.

According to one configuration of the invention, a limiting arrangement can be provided for limiting the maximum relative movement of the seat part and backrest part. In particular, two stops can be provided, wherein one stop defines the maximum opening angle between the seat part and backrest part and one stop defines the minimum angle between the seat part and backrest part.

Furthermore, a manually operable locking mechanism can be provided for locking the relative position of the seat part and backrest part. Due to this measure, the opening angle between the backrest part and the seat part can be determined.

A manually operable seat tilt limiter can also be provided. The locking mechanism and the seat tilt limiter can be combined.

A pin can be arranged on the backrest part, which pin is guided in a slot of a guide part arranged on the support part. The two end points of the slot represent the stops that limit the relative movement of the seat part and backrest part. In order to ensure particularly good stability, the pin and guide part can be made of metal.

A latch can be pivotably arranged on the guide part that comprises both a stop for the pin and a locking receptacle for the pin. If the latch is in a position in which the pin can strike against the stop, the seat tilt can be limited by the stop. If the latch is in a position in which the pin is held by the locking receptacle, the relative movement of the seat part and backrest part is prevented.

Further advantages arise if an assembly with a receptacle for the support of a base is arranged on the support part. In particular, if the assembly is made of metal, sufficient stability arises for accommodating the support of the base. The locking mechanism and the seat tilt limiter can also be implemented on the assembly, in order to realize these functions with sufficient stability. In the event of recycling, the assembly can simply be detached from the multi-joint body, such that both components can be recycled separately.

A guide for accommodating the seat and/or the backrest can be arranged on the seat part and/or the backrest part. This makes it easier to assemble the seat and/or backrest. The guides can be designed in the form of a dovetail.

A plug-in connecting element for attaching a seat element and/or backrest element can be arranged on the seat part and/or the backrest part. This constitutes an easy way for assembling the seat and backrest. The seat part and the backrest part can be a component or central element of the seat or backrest.

Armrests can be arranged on the backrest part in a material-locking manner. In particular, they can be molded onto the backrest part or be an integral component thereof.

A chair, in particular an office chair, with a central unit according to the invention, also falls within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages of the invention can be found in the description and the drawings. Likewise, according to the invention, the aforementioned features and those which are to be explained below can each be used individually or together in any desired combinations. The embodiments shown and described are not to be understood as an exhaustive list, but, rather, have an exemplary character for the description of the invention.

In the drawings:

FIG. 1 is a side view of a multi-joint body with four film hinges;

FIG. 2 is a perspective view of the multi-joint body with four joints in an initial position;

FIG. 3 is a representation corresponding to FIG. 2 with the backrest pivoted backwards;

FIG. 4 shows an embodiment of a multi-joint body with which a seat part and a support part are connected by a spring arrangement;

FIG. 5 is a representation corresponding to FIG. 4 with the backrest pivoted backwards;

FIG. 6 is a sectional view of a multi-joint body with a spring arrangement with a plurality of spring elements.

FIG. 7 is a representation corresponding to FIG. 6 with an activated spring element;

FIG. 8 is a configuration of a multi-joint body with a flexurally elastic front part;

FIG. 9 is a representation corresponding to FIG. 8, wherein the backrest is pivoted backwards;

FIG. 10 shows a multi-joint body with which only three joints are designed as solid-body joints;

FIG. 11 shows the multi-joint body of FIG. 10, wherein one joint comprises a rotation pin;

FIG. 12 shows a central unit with a multi-joint body and a locking mechanism;

FIG. 13 shows a central unit with a limiting arrangement;

FIG. 14 shows the central unit with a locking mechanism;

FIG. 15 shows the blocked locking mechanism;

FIG. 16A shows a multi-joint body with receptacles for a seat and a backrest;

FIG. 16B shows the multi-joint body of FIG. 16A while the seat and backrest are attached;

FIG. 16C shows a backrest suitable for attaching;

FIG. 17 shows a further multi-joint body with plug-in connecting elements for attaching seat and backrest elements;

FIG. 18 shows a multi-joint body with armrests arranged on the backrest part in a material-locking manner;

FIG. 19 shows a side view of a multi-joint body with mountings for one or more spring elements;

FIG. 20 shows a side view of the multi-joint body of FIG. 19 with inserted spring element;

FIG. 21 shows a side view of a spring element; and

FIG. 22 shows a perspective view of a spring element.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 shows a central unit 10 of a chair, in particular an office chair, with a multi-joint body 12. The multi-joint body 12 comprises a seat part 14 for a seat 16, a backrest part 18 for a backrest 20, a support part 22 for a base and a front part 24. The seat part 14 is connected to the backrest part 18 via a joint 26 which is designed as a solid-body joint. The backrest part 18 is connected to the support part 22 via a joint 28 which is designed as a solid-body joint. The support part 22 is connected to the front part 24 via a joint 30 which is designed as a solid-body joint. The front part 24 is connected to the seat part 14 via a joint 32 which is designed as a solid-body joint. The joints 26, 28, 30, 32 have a lower material thickness than the seat part 14, the backrest part 18, the support part 22 and the front part 24. The seat part 14, the backrest part 18, the support part 22 and the front part 24 are designed to be rigid. The joints 26, 28, 30, 32 are designed to be less rigid, namely flexible, in particular elastic. The material thickness of the joints 26, 28, 30, 32 can be the same or different. In each case, two joints can also have the same material thickness.

In the exemplary embodiment shown, the multi-joint body 12 is designed as a four-joint system. The seat part 14, the backrest part 18, the support part 22 and the front part 24 along with the joints 26, 28, 30, 32 arranged between them surround an opening 34. The multi-joint body 12 can be designed as a single piece. In particular, the joints 26, 28, 30, 32 can in each case be formed in one piece, in particular in a material-locking manner, with the parts adjoining thereon. The seat 16 and the backrest 20 can be separate parts and can be connected to the multi-joint body 12. However, it is also conceivable that the seat 16 and the backrest 20 are also formed in one piece, in particular in a material-locking manner, with the multi-joint body 12. In particular, the multi-joint body 12, if applicable together with the seat 16 and backrest 20, can be made of plastics material and manufactured in an injection molding process.

FIG. 2 shows a perspective view of the central unit 10 of FIG. 1 in an initial position. This means that no force was exerted on the backrest 20 or the seat 16 and thus the multi-joint body 12 was not deformed.

With the representation in FIG. 3, a force was exerted on the backrest 20, such that it was pivoted backwards. As a result, a different shape of opening 34 arises. Given that the joints 26, 28, 30, 32 are made of elastic material, they automatically return to the position shown in FIG. 2 if no further external force is exerted on the backrest 20. In FIG. 3, the backrest 20 and the seat 16 are at a greater angle to one another than in FIG. 2.

With the embodiment of the central unit 10a in accordance with FIG. 4, a spring arrangement 36 is provided between the seat part 14 and the support part 22. The spring arrangement 36 can be formed in one piece, in particular in a material-locking manner, with the seat part 14 and the support part 22. The spring arrangement 36 can increase the resistance for the swinging back of the backrest 20. The spring arrangement 36 effectively divides the opening 34 into two halves.

FIG. 4 shows the central unit 10a in an initial position, i.e., without the backrest 20 being pivoted relative to the seat 16.

FIG. 5 shows the central unit 10a after the backrest 20 was pivoted backwards relative to the seat 16. It can be seen that both the spring arrangement 36 and the opening 34 were deformed. The spring arrangement 36 can only comprise one spring element which is designed in the form of a leaf spring. However, the spring arrangement 36 can also be designed in accordance with FIG. 6.

The spring arrangement 36 of FIG. 6 comprises a plurality of spring elements 38, 40. The spring element 38 is firmly connected to the seat part 14 and the support part 22, in particular formed in one piece therewith. In the exemplary embodiment shown, the spring element 40 is only connected to the seat part 14, in particular is formed in one piece therewith. The end 42 of the spring element 40 on the support part side is rotatably mounted on the support part 22 via an axis of rotation 44. If the seat part 14 thus moves relative to the support part 22, the end 42 can be pivoted relative to the support part 22, such that the spring element 40 exerts no effect. For activating the spring element 40, a slider 46 is provided, which can be displaced relative to the support part 22. The slider 46 can be pushed into the recess 48 for activating the spring element 40, as shown in FIG. 7. In this case, the end 42 can no longer be pivoted about the axis 44, such that the spring element 40 exerts its effect and counteracts a relative movement of the seat part 14 and support part 22 when exerting a force on the backrest 20. A spring element analogous to spring element 38 can also be provided. In particular, the spring element 40 can be arranged between two spring elements 38.

FIG. 8 shows a further variant of a central unit 10b. This embodiment comprises only the joints 26, 28, 32. The front part 24a is designed to be flexurally elastic. It has a material thickness that is less than that of the seat part 14, the backrest part 18 and the support part 22, but greater than that of the joints 26, 28, 32. Due to this configuration, the stiffness of the multi-joint body 12b can further increase. In particular, the force required to deform the multi-joint body 12 can be increased in this way compared to the configuration of FIG. 1.

FIG. 8 shows the multi-joint body 12b in an initial position, i.e., without the backrest 20 being pivoted relative to the seat 16. FIG. 9 shows the situation after the backrest 20 was pivoted relative to the seat 16. It can be seen here that the front part 24a was deformed as a result. With the configuration in accordance with FIGS. 8 and 9, the front part 24a is formed in one piece with the support part 22. It would also be conceivable to omit the joint 32 and connect the front part 24a directly to the seat part 14, while retaining the joint 30 between the front part 24a and the support part 22.

FIG. 10 shows a further embodiment of a central unit 10c. The multi-joint body in turn comprises a seat part 14, a backrest part 18, a support part 22 and a front part 24. The seat part 14 and the backrest part 18 are connected by a joint 26 designed as a solid-body joint. The support part 22 and the front part 24 are connected by a joint 30 designed as a solid-body joint. The front part 24 and the seat part 14 are connected by a joint 32 designed as a solid-body joint. In this case, however, the joint 28 is not designed as a solid-body joint. A pin receptacle 50 is formed on the backrest part 18 and a pin receptacle 52 is formed on the support part 22. The pin receptacles 50, 52 can be connected by a pin, in order to thereby form a joint 28. In this case, the multi-joint body 12c thus only comprises three solid-body joints. The special feature of this embodiment is that the multi-joint body 12c shown in FIG. 10 can also be manufactured in one piece using an injection molding process.

FIG. 11 shows the multi-joint body 12c with the joint 28 completed, i.e., after a pin 54 was inserted into the pin receptacles 50, 52. In principle, it is also conceivable to design one of the other joints 26, 30, 32 as a joint with a pin. However, it is preferable that at least three of the joints 24, 28, 30, 32 are designed as solid-body joints.

FIG. 12 shows a central unit 10d with a multi-joint body 12. An assembly 60, in particular a metal assembly, is arranged on the multi-joint body 12. On the one hand, this comprises a receptacle 62 for accommodating a support of a base (not shown here). Furthermore, a limiting arrangement, a locking mechanism and a seat tilt limiter are formed on the assembly 60, as can be seen from the following representations.

FIG. 13, in which half of the central unit 10d is hidden, shows that a guide part 64 is provided that comprises a slot 66. A pin 68 is arranged in the slot 66 which is fixed to the backrest part 18. The slot 66 limits the range of movement of the pin 68. As a result, the relative movement of seat part 14 and backrest part 18 is limited. The two ends of the slot 66 represent end stops for the pin 68.

Furthermore, a latch 70 can be seen, which is pivotably arranged on the guide part 64. The latch 70 is coupled to an operating handle 74 by means of a toggle mechanism 72. The latch 70 can be pivoted by actuating the operating handle 74.

In the pivoted position of the latch 70 shown in FIG. 14, a stop 76 blocks further movement of the pin 68 in the slot 66. As a result, the mobility of the seat part 14 is limited, such that a manually operable seat tilt limiter is realized. However, a further relative movement of the seat part 14 and the backrest part 18 in the sense of an increase in the angle between the seat part 14 and the backrest part 18 remains possible until the pin 68 abuts against the right end of the slot 66.

FIG. 15 shows a further pivoted position of the latch 70, wherein the pin 68 is received in a locking receptacle 78 of the latch 70. A locking mechanism is thus realized. The relative position of the seat part 14 and the backrest part 18 is locked. The assembly 60 can be a metal assembly. However, it can also be made of a different material, such as plastics material. In any case, the assembly 60 can be completely detached from the multi-joint body, such that it can be recycled.

FIG. 16A shows a multi-joint body 12d, with which the seat part 14 comprises a guide 90 onto which a seat can be slid. In the exemplary embodiment shown, the guide 90 is also configured with a dovetail-shaped cross section. As a result, it is ensured that the pushed-on seat cannot simply be removed upwards. To ensure that the seat remains in its position, the guide 90 comprises latching recesses 92, such that the seat can latch onto the guide 90 with corresponding latching lugs.

A guide 94 is provided on the backrest part 18 for accommodating a backrest. The guide 94 is also configured with a dovetail-shaped cross section. The guides 90, 94 can be formed in a material-locking manner with the seat part 14 or the backrest part 18. In particular, the guides 90, 94 can be molded onto the seat part 14 or the backrest part 18, in particular manufactured at the same time as the multi-joint body 12d.

The recesses 95, 97 are provided on the backrest part 18, which recesses can be designed as through recesses. The bending stiffness of the backrest part 18 can be adjusted by suitably selecting the number, shape and size of the recesses 95, 97.

FIG. 16B shows that the backrest 20 can be pushed onto the guide 94 in the direction of arrow 98. The seat 16 can be pushed onto the guide 90 in the direction of arrow 100. As a result, a particularly easy fastening of the seat 16 and backrest 20 to the multi-joint body 12d arises.

FIG. 16C shows that the backrest 20 comprises a guide 96 on its rear side corresponding to the guide 94, with which the backrest 20 can be pushed onto the guide 94. The guide 96 is configured to be substantially U-shaped, such that the upper horizontal connecting bar forms a stop that prevents the backrest 20 from being pushed too far onto the guide 94. The seat 16 can comprise a corresponding guide on its underside.

With the configuration of a multi-joint body 12e in accordance with FIG. 17, it can be seen that both the seat part 14 and the backrest part 18 comprise plug-in connecting elements 104, 106 designed as pin receptacles. Corresponding plug-in connecting parts 104, 106 are provided on the opposite side of the seat part 14 or the backrest part 18. Seat elements 108 and backrest elements 110 can simply be plugged into the plug-in connecting elements 104, 106 with corresponding plug-in connecting elements 112, 114 formed as pins, in order to thereby be simply arranged on the multi-joint body 12e. In particular, the seat part 14 and the backrest part 18 can in each case comprise four plug-in connecting elements 104 and 106.

With the embodiment of the multi-joint body 12f in accordance with FIG. 18, it can be seen that armrests 120, 122 are arranged on the backrest part 18. In particular, the armrests 120, 122 are formed in a material-locking manner with the backrest part 18. They can be molded onto the backrest part 18. The armrests 120, 122 together with the upper portion 124 of the backrest part 18 form a U-shaped design. The backrest 20, which is only shown schematically here, can be fastened to the portion 124 of the backrest part 18.

Furthermore, it is indicated that the seat 16 can be inserted into openings 126 of the seat part 14 with corresponding extensions or can be fastened to the seat part 14 through the openings 126 by means of screws. FIG. 18 also indicates a base 128 which is connected to the support part 22 via a support 130.

FIG. 19 shows a central unit 10e of a chair, in particular an office chair, with a multi-joint body 12g. The multi-joint body 12g comprises a seat part 14 for a seat 16, a backrest part 18 for a backrest 20, a support part 22 for a base and a front part 24. The seat part 14 is connected to the backrest part 18 via a joint 26 which is designed as a solid-body joint. The backrest part 18 is connected to the support part 22 via a joint 28 which is designed as a solid-body joint.

The support part 22 is connected to the front part 24 via a joint 30 which is designed as a solid-body joint. The front part 24 is connected to the seat part 14 via a joint 32 which is designed as a solid-body joint. The joints 26, 28, 30, 32 have a lower material thickness than the seat part 14, the backrest part 18, the support part 22 and the front part 24. The seat part 14, the backrest part 18, the support part 22 and the front part 24 are designed to be rigid. The joints 26, 28, 30, 32 are designed to be less rigid, namely flexible, in particular elastic. The material thickness of the joints 26, 28, 30, 32 can be the same or different. In each case, two joints can also have the same material thickness.

The seat part 14 and the support part 22 each comprise a mounting 14a, 22a or holder for a spring arrangement comprising at least one spring element. The mountings are in the shape of a dove-tail. They also function as guides for a spring element, so the spring element can be inserted by pushing it in form the side without having to use a tool.

FIG. 20 shows the multi-joint body 12g with a spring element 38a of a spring arrangement 36a being installed. The spring arrangement 36a serves for providing sufficient resistance for the tilting back of the backrest. The spring arrangement 36a is arranged between the seat part 14 and the support part 22. In order to adjust the spring force, several spring elements 38a can be installed in the mountings 14a, 22a next to one another. Alternatively or additionally, the material thickness and/or the width and/or the material of the spring elements 38a can be varied in order to adjust the spring force and thus to adjust the base part 10e for different user weights. Hence, spring elements 38a can be exchanged for different spring elements 38a in order to adjust the spring force, or different spring elements 38a can be combined.

FIG. 21 shows a side view of a spring element 38a, which is detachable from the multi-joint body 12g. The spring element 38a has an S-shaped configuration. The end parts 38a′, 38a″ are wider than the rest of the spring element 38a and have a complementary configuration to the mountings 14a, 22a. They are adapted to the mountings 14a, 22a.

FIG. 22 shows a perspective view of the spring element 38a. Several spring elements 38a can be provided and a user can install the appropriate number of spring elements 38a in order to adjust a chair having the central unit 10e to his needs.

Although only a few embodiments of the present invention have been shown and described, it is to be understood that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.

CENTRAL UNIT FOR A CHAIR

Information

Publication Number

Date Filed

Date Published

Inventors

Original Assignees

CPC

International Classifications

Abstract

Description

Claims

Priority Claims (1)