WO2013029575A1

WO2013029575A1 - Seating device with a tilting seat part

Info

Publication number: WO2013029575A1
Application number: PCT/CZ2012/000084
Authority: WO
Inventors: Michal ŠORM
Original assignee: Sorm Michal
Priority date: 2011-08-29
Filing date: 2012-08-27
Publication date: 2013-03-07
Also published as: CZ2011532A3

Abstract

The invention relates to a seating device with a tilting seat part, which is mounted for tilting motion by means of tilting joint (2) on an upper portion (31) of a support member (3) for tilting movement from its neutral - horizontal position, whereby a lower portion (32) of the support member (3) is mounted on a base (4) and a first resilient element (5) is arranged between the seat part (1) and the support member (3) to cause a resistance against the tilting movement of the seat part (1) from its neutral position comprising as essential feature the first resilient element (5) formed as a vertically mounted slim straight - lined spring (51), the upper end of which is mounted at the central area of the seat part (1) or its frame (11) and its lower end is mounted within the support portion (3) along a vertical axis (O) passing through the center of the tilting joint (2) of the seat part (1).

Description

Seating device with a tilting seat part TECHNICAL FIELD

The invention relates to a seating device with a tilting seat part mounted on a support member including a base and specifically designed for office or similar chairs.

DESCRIPTION OF PRIOR ART

The known prior art include seating devices, with a tilting seat part tiltably mounted on a support member including a base. The angular amplitude of the seat part from the equilibrium i.e. horizontal position to all directions is controlled by a spring mechanism which, after unloading the seat part returns the seat part to the original equilibrium position.

For example, DE 10 2005 033 052 A1 discloses a seating device the seat part of which is spring cushioned by an annular airbag disposed between the lower side of the seat part and its frame. The characteristics of the spring action of the annular airbag may be manually adjusted by changing the air pressure in the annular airbag. A disadvantage of this structure resides in the need of a large built up space under the seat part particularly in the horizontal direction and impossibility of self adjustment of the spring characteristics by the weight of the seating person.

DE 20 55 687 presents a seating device, the seat part of which is spring biased by a helical spring in the vertical direction and also laterally upon deflection of the seat part. A disadvantage of this design is a relatively great diameter of the helical spring, which shall ensure the stability when the seat part is deflected as well as the impossibility to adjust manually the spring characteristics dependent on the weight of the seating person.

Similar drawbacks of a large built up space for the spring mechanism enabling the seat part to be tilted and the impossibility of self adjustment of the spring characteristics regulating the tilting angle of the seat part are apparent from DE 201 06 173 U1 , EP 0298928, EP 0079530 B1 and DE 97 42 100 A1.

U.S. 5,573,304 offers a seating device, consisting of seat part mounted tiltably on the upper portion of a support member the lower portion of which is fixed to a base. The upper portion of the support member props up resiliently the seat part by means of a second resilient element in a vertical direction and the deflection amplitude of the seat part in all directions is spring biased by means of a first resilient element disposed between the seat part and the upper portion of the support member. This first resilient element is composed of a number of pre-stressed curved leaf springs fixed by their upper ends to the periphery of the seat part and by their lower ends to the upper portion of the support member. The support member is mounted telescopically on the lower portion of the support member. The lower portion and the upper portion of the support member are spring biased towards each other by a second resilient element, i.e. a vertical helical spring. In another alternative embodiment, the seat part is mounted by means of its lower central pivot in a first resilient element in the form of a rubber disc. The rubber disc is mounted at its perimeter in the upper end of a support member designed as a C-shaped leaf spring the lower end of which is secured to the base. Upon loading the seat part by an occupant the center of gravity of which lies in the vertical axis passing through the tilting point of the seat part the force originating in the seat part is transferred in the vertical direction always through the first resilient element to the second resilient element which both are disposed in series one above other and the seat part is shifted in vertical direction due to the elastic deformation of both the resilient elements. If the occupant displaces his center of gravity out of said vertical axis, the resisting force of the resilient element is directed against the tilting movement of the seat part.

A disadvantage of this solution is that in case of the same deflection of the occupant's center of gravity the heavier occupant experiences greater deflection of the seat part than a lightweight occupant. The reason is that the characteristics of the first resilient element are self-adjustable dependent on the weight of the occupant. The object of the present invention is to provide a seating device by which spring acting against the deflection of the seat part, i.e. the first resilient element, occupies a minimum space, preferably in the horizontal direction, and the characteristics of such a spring is manually adjustable. More advantageously, the spring is hidden inside the vertical support member of the seating device.

Another object of the present invention is to provide a seating device, by which the characteristics of the first resilient element controlling the tilting motion of the seat part is self-adjustable dependent on the weight of the occupant. SUMMARY OF THE INVENTION

The above discussed drawbacks are overcome and said objects are accomplished by a seating device according to the preamble of the first claim comprising as essential features a first resilient element in the form of a vertically mounted slim straight-lined spring the upper end of which is mounted at a central area of a seat part and the lower end of which is mounted on the support part along a vertical axis passing through a tilting joint of the seat part.

Said structure enables space reducing mounting of the first resilient element in the vertical direction to control the tilting angle of the seat part in all directions. By refraining from a robust spring device under the seat part used as yet a more esthetic and slim implementation of the support member of the seating device is possible.

According to another advantageous aspect of the invention, the lower end of the vertical slim straight-lined spring is slidably mounted in a guiding hole of a partition wall, which wall is fixedly mounted or vertically adjustable within the support part. In the embodiment with the fixed partition wall the rigidity of the slim vertical straight- lined spring which controls the tilting angle of the seat is dependent on the factory setting only while with the slidably mounted partition wall the user may manually control the rigidity, i.e. the characteristics of the slim straight-lined spring as the user may see appropriate.

It is also useful, if the upper portion of the support member is separated from the lower portion and a second resilient element is located between the both portions to provide a spring mounting of the seat part in the vertical direction. Such a design enables a self-adjustment of the characteristics of the slim straight-lined spring controlling the tilting angle of the seat part in such a manner that the same deflection of the center of gravity of the seating person from the vertical axis passing through the tilting point of the seat part produces the same tilting angle of the seat part without regard to the weight of the seating person. Accordingly, the rigidity of the straight-lined vertical spring is self-adjustable by the weight of the seating person by shortening its working or operating length, respectively. The upper portion consists preferably of a telescopic tube with an upper flange situated on its higher section and the lower portion consists of a telescopic tube with a lower flange on its lower section whereby a second resilient element in the form of a helical spring is located between the upper and the lower flange. This embodiment provides for a perfect guidance of the seat part in the vertical direction. Moreover, the first resilient element and optionally the second additional resilient element are hidden within said tubes which arrangement contributes not only to the safety but also to the elegancy of the overall design of the seating device.

According to another advantageous embodiment, the slim straight-lined spring is designed as a rod-shaped spring with a circular cross-section. This embodiment makes possible a good axial guidance of the lower end of the rod-shaped spring and the unchanged spring characteristics when the seat part is tilted in any direction.

In certain cases, it may be useful if the slim straight-lined spring is designed as a rod -shaped spring with a rectangular cross-section. Such a spring may, due to its cross- section configuration, exhibit different spring characteristics in different directions in which the seat part swings.

The slim straight-lined spring may also be formed as a helical spring with a minimum helix lead. This configuration enables to reduce the length of the slim straight-lined spring and accordingly, the structural height of the support member due to a great bending deformation at a relatively short operating length of such a type of spring.

It is also useful if the slim straight-lined spring is constituted of a bundle of very thin straight-lined springs and such a bundle has circular or another cross-section. Such spring is less rigid than a spring constituted of a single rod of the same cross section area but exhibits a great bending deformation at a relatively short operating length.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain examples of the invention are further described with reference to the accompanied drawings in which: Fig. 1 shows a vertical cross-section of a 1 alternative embodiment of the seating device with a manual adjustment of the spring characteristics;

Fig. 2a shows a detail A the seating device of Fig. 1 with an unloaded seat part;

Fig. 2b shows a detail A of the seating device of Fig. 1 with a loaded seat part where the center of gravity of the seating person lies in the vertical axis of the seating device;

Fig. 2c shows a detail A of the seating device of Fig. 1 with a loaded seat part where the point of gravity of the seating person lies out of the vertical axis of the seating device;

Fig. 3a shows a detail of the 2^nd alternative embodiment with a self-adjustment of the spring characteristics like in Fig. 2a;

Fig. 3b shows a detail of the 2^nd alternative embodiment with self-adjustment of the spring characteristics like in Fig. 2b;

Fig. 3c shows a detail of the 2^nd alternative embodiment with a self-adjustment of the spring characteristics like in Fig. 2c;

DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. 1 shows a seating device represented by an office chair consisting of a seat part 1 with an integrated backrest, the seat part 1 of which is arranged on a frame 11 , which is mounted on an upper portion 31 of a support member 31 by means of tilting joint in the form of an elastic member. A lower portion 32 of the support member 3 is mounted on the base 4 by means of which the seating device rests on the ground or a floor. It is to be understood that the tilting device according to the invention may be adapted for tilting into all direction by means of a ball joint or in one plane only by means of rotatable bearing or in two planes by means of a cross pin joint or otherwise. Also the seat part need not be mounted for tilting motion on the support member 3 at its center, i.e. in the center of gravity of the seat part, but in area nearby such a center. The tilting joint 2, which is constituted by an elastic bloc enables the seat part 1 to tilt into all directions, i.e. in any direction, to which the seating person displaces its center of gravity T from the vertical axis O passing through the center of the tilting joint 2. The elastic bloc may also enable a slight elastic motion in the vertical direction, which motion however may not be regarded as a spring action in the vertical direction. To control the deflection of the seat part 1 from the basic, i.e. the horizontal position and not to allow the full deflection till the abutment even upon a minor deflection of the center of gravity of the seating person from the vertical axis

0, the tilting motion is opposed by a resilient force of a first resilient element 5 which holds the seat part 1 substantially in a horizontal plane, i.e. in the basic position as shown in Fig. 2a and Fig. 3a.

In examples of embodiments, the first resilient element 5 consists of a vertically mounted rod-shaped spring 51 , the upper end of which is connected to the seat part

1 , or the frame 11 respectively, by means of a sleeve 13 passing through the elastic bloc of the tilting joint 2. The lower end of the rod-shaped spring 51 is slidably mounted in the hole 71 of a partition wall 7 which, is engaged with the upper portion 31 according to the 1^st alternative embodiment and with the lower portion 32 pursuant to the 2^nd alternative embodiment. It is to be understood that the lower end of the rod-shaped spring 51 may be fixed within the partition wall 7 and its upper end may be slidably mounted within the sleeve 13. In order to reduce the friction between the end of the rod-shaped spring 51 and the hole 71 , a slidable bush or a antifriction bearing may be inserted into the hole 71. In both alternative embodiments, the attachment of the partition wall 7 to the support member 3 may be effected as a non-dismantling or dismantling connection. The dismantling connection enables optional setting of the partition wall 7 in the vertical direction by means of a known per se arresting device 72. Upon tilting the seat part 1 on the elastic bloc 2 initiated by deflection of the seating person center of gravity from the vertical axis O, the sleeve 13 is tilted and bends the slim straight-lined spring 1 along its operating length L. The operating length L is defined by the pitch between the upper and the lower rest end of the straight-lined spring 51 as shown in Fig. 2c and Fig. 3c. The shorter is the operating length L of the slim straight-lined spring, the more rigid is the spring and on the contrary. Due to the vertical optional setting of the partition wall 7 with the guiding hole 71 inside the upper portion 31 , the operating length L and consequently the rigidity of the straight-lined spring 51 may be manually adjusted. Both the alternative embodiments are characterized by the fact that the spring device is slim and occupies, specifically in the horizontal level, a minimum space. This is also enabled by a slim, elegant design of the support member 3 as it is best shown in Fig. 1. The 1 alternative embodiment of the seating device according to the invention provides a spatially reduced arrangement of the spring loaded tilting of the seat part in the embodiment with the adjustable partition wall 7 and optional manual setting of the characteristics of the elasticity or rigidity of the spring loaded tilting.

Moreover, the 2^nd alternative embodiment enables the self-adjustment of the characteristics of the tilting elasticity or rigidity of the seating part through the weight of the seating person.

According to the 1^st alternative embodiment, the support member 3 comprises the upper portion 31 which is far longer than the upper portion according to the 2^nd alternative embodiment and the partition wall 7 situated in its lower section. The upper portion 31 is connected by its lower section with the lower portion 32. The lower portion 32 has a lower pivotally shaped section which is slidably mounted in the base 1 and loaded by the second resilient element 6 against the base 1. Since the partition wall 7 is mounted within the upper portion 31 , which is secured to the lower portion 32, the operating length L of the first resilient element 5 in the vertical direction is not shortened in course of the spring action. This 1^st alternative embodiment is shown in Fig. 1 to Fig. 2c, whereby Fig. 2a to 2c illustrate in detail various loading conditions of the seat part 1.

According to the 2^nd alternative embodiment illustrated in Fig. 3a to Fig. 3c, the partition wall 7 with the guiding hole 71 is connected to the lower portion 32 either fixedly or slidably in vertical direction. The lower portion 32 is formed as a telescopic tube, the lower section of which is secured to the base 4 and provided with a lower prop flange 320 to support the lower end of the second resilient element 6. The upper portion 31 has also the form of a telescopic tube, the lower section of which is slidably mounted in the lower portion 32. The higher end of the upper portion 31 is provided with an upper prop flange 3 0 for supporting the upper end of the second resilient element 6. The higher end of the upper portion 31 further bears the tilting joint 2 of the seat part 1 designed as an elastic bloc. Since upon loading the seat part 1 by a seating person - not shown - the upper portion 31 is shifted in the vertical direction towards the lower portion 32 against the action of the second resilient element 5, the slim straight-lined spring 51 moves over the same distance through the guiding hole 71. Thereby, the starting operating length L of the slim straight-lined spring will be shortened to the operating length L1 proportionally to the weight of the seating person (vise Fig. 3b). This proportion is dependent on the characteristics of the second resilient element 5, which is determined by its original shape. If, for example, the second resilient element 5 is designed as a helical spring having a constant helix lead and a constant diameter, than the proportion is direct. The shortening of the operating length L to the operating length L1 results in increased rigidity of the slim straight-lined spring 51 as described above. In this case the rigidity of the slim straight-lined spring 51 is self-adjustable proportional to the weight of the seating person.

The slim straight-lined spring 51 may be a rod-shaped spring with a circular, oval, rectangular or another cross-section dependent on whether its rigidity shall be the same in all tilting directions of the seat part 1 or if it shall be different in particular directions. The slim straight-lined spring 51 may be also designed as a bundle of straight-lined rod springs of small cross-section, whereby the cross-section of the bundle may also be of a various shape. Such a spring exhibits higher flexibility by the same rigidity than a spring of the same cross-section. For the same reason, a helical spring of small cross-section with a minimum helix lead may also serve this purpose.

Claims

1. A seating device with a tilting seat part (1) mounted for tilting motion by means of a tilting joint (2) on an upper portion (31) of a support member (3) for tilting movement from its neutral - horizontal position, whereby a lower portion (32) of the support member (3) is mounted on a base (4) and a first resilient element (5) is arranged between the seat part (1) and the support member (3) to cause a resistance against a tilting movement of the seat part (1) from its neutral position,

characterized in that

the first resilient element (5) is formed as a vertically mounted slim straight- lined spring (51) the upper end of which is mounted at the central area of the seat part (1) or its frame (11) and the lower end is mounted within the support portion (3) along a vertical axis (O) passing through the center of the tilting joint (2) of the seat part (1).

2. The seating device according to claim 1 , wherein the lower end of the straight- lined spring (51 ) is slidably mounted in a guiding hole (71) of a partition wall (7) which is fixedly mounted or vertically adjustable within the support portion (3).

3. The seating device according to claim 2, wherein the upper portion (31) of the support member(3) is secured to the lower portion (32), which is slidably mounted and spring loaded in the vertical direction within the base (4), whereby a second resilient element (6) for spring loading the seat part (1 ) in the vertical direction is located between the base (4) and the upper portion (31) whereby the partition wall (7) is mounted in the upper portion (31).

4. The seating device according to claim 2, wherein the upper portion (31) of the support member (3) is separated from the lower portion (32) and a second resilient element (6) for spring loading the seat part (1 ) in the vertical direction is located between the upper portion (31) and the support member (3) and the partition wall (7) is mounted in the lower portion (32).

5. The seating device according to claim 3, wherei formed as a telescopic tube with an upper flange (310) at its higher end and the lower portion (32) is formed as a telescopic tube with a lower flange (320) at its lower end, whereby the second resilient element (6) formed as a helical spring is located between the upper flange (310) and the lower flange (320).

6. The seating device according to any of the preceding claims 1 to 5, wherein the tilting joint (2) is formed as an elastic bloc (21), which is fixed within the higher section of the upper portion (31).

7. The seating device according to any of the preceding claims 1 to 6, wherein the upper end of the slim straight-lined spring (51) is secured in the central area of the seat part (1) by means of a sleeve (13) mounted by its peripheral surface in the tilting joint (2).

8. The seating device according to any of the preceding claims 1 to 7, wherein the slim straight-lined spring (51) is formed as a rod-shaped spring having a circular cross-section.

9. The seating device according to any of the preceding claims 1 to 7, wherein the slim straight-lined spring (51) is formed as a rod-shaped spring having a rectangular cross-section.

10. The seating device according to any of the preceding claims 1 to 7, wherein the slim straight-lined spring (51 ) is formed as a helical spring with a minimum helical lead.

11. The seating device according to any of the preceding claims 1 to 7, wherein the slim straight-lined spring (51) is constituted by a bundle of a very thin straight- lined springs and the bundle has a circular or another cross-section.