US20120098313A1

US20120098313A1 - Reclining Chair

Info

Publication number: US20120098313A1
Application number: US12/911,487
Authority: US
Inventors: Emilian Dan Cartis; Mark McKenna
Original assignee: Humanscale Corp
Current assignee: Humanscale Corp
Priority date: 2010-10-25
Filing date: 2010-10-25
Publication date: 2012-04-26

Abstract

In the specification and drawings a reclinable chair is described and shown having a recline mechanism pivotally attaching a backrest to a support assembly. The recline mechanism comprises a coupler operatively connected to an elastomeric spring assembly. The elastomeric spring assembly has four elastomeric inserts positioned between a polygon-shaped core and a polygon-shaped exterior housing. The exterior housing is fixed to the backrest, while the core is fixed to the coupler. The exterior housing has an outwardly protruding tooth positioned between the coupler's inwardly protruding preload stop and the coupler's inwardly protruding recline stop such that the primary tooth engages the preload stop when the chair is in a rested state and engages the recline stop when the chair is in a fully reclined state.

Description

I. BACKGROUND OF THE INVENTION

In order to increase the comfort of a person seated in a chair, manufacturers have long made chairs with a backrest that is capable of reclining several degrees with respect to a vertical position. Today, seats with a reclining backrest are used in homes, offices, and vehicles. A common feature of reclinable chairs is a spring mechanism to bias the chair components toward an upright position. These mechanisms typically include a spring capable of returning the chair to the upright position when the rearwards thrust applied by the user ceases. The spring force stored during recline serves to assist the user when returning to an upright position.
Traditionally, the spring mechanisms used in reclinable chairs have featured steel springs. However, steel springs have low natural damping, making the springs prone to suffer from unwanted oscillation and vibration. Steel springs are also succeptible to corrosion and damage due to shock loads. Elastomeric springs, on the other hand, have high natural damping, increased shock load capabilities, and are largely resistant to corrosion. Accordingly, it would be advantageous to have a recline mechanism featuring an elastomeric spring, thereby providing an ergonomic, self-dampened reclinable chair.

II. SUMMARY OF THE INVENTION

A reclinable chair having the features of the present invention comprises a recline mechanism pivotally attaching a backrest to a support assembly. The recline mechanism can comprise a coupler operatively connected to an elastomeric spring assembly. The recline mechanism's elastomeric spring assembly can comprise at least four elastomeric (rubber) inserts positioned between a polygon-shaped core and a polygon-shaped exterior housing. The exterior housing is fixed to the backrest, while the core is fixed to the coupler. In this arrangement, the exterior housing will rotate about the core when the backrest is reclined. In order to provide a means for applying a preload to the spring assembly, the exterior housing can have at least one outwardly protruding tooth that engages an inwardly-protruding preload stop of the coupler.
In an embodiment of the invention, the recline mechanism can also feature a means for preventing the spring elastomeric assembly from extending beyond its maximum torsional range during recline. The coupler can comprise an inwardly-protruding recline stop spaced apart from the inwardly protruding preload stop. In this arrangement, the elastomeric spring assembly's outwardly protruding tooth will be positioned between the preload stop and the recline stop such that the tooth engages the preload stop when the chair is in a rested state and engages the recline stop when the chair is in a fully reclined state.
The above summary is not intended to describe each illustrated embodiment or every possible implementation. It should also be understood that the specific devices illustrated in the attached drawings, and described in the following description, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

III. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a right-side perspective view of an embodiment of the reclinable chair of the present invention.

FIG. 2 is a is a right-side perspective view of the embodiment of the reclinable chair shown in FIG. 1 with the backrest removed.

FIG. 3 is a front perspective view of an embodiment of the chair's recline mechanism.

FIG. 4 is a rear perspective view of an embodiment of the chair's recline mechanism.

FIG. 5 is an exploded view of the recline mechanism's elastomeric spring assembly.

FIG. 6 is an exploded view of an embodiment of the chair's recline mechanism and backrest.

FIG. 7 is a perspective view of an embodiment of the chair's recline mechanism prior to being attached to the backrest.

FIG. 8 is a perspective view of an embodiment of the chair's recline mechanism attached to the backrest.

FIG. 9 is an exploded view showing the recline mechanism's coupler being attached to the elastomeric spring assembly.

FIG. 10 is a side view of an embodiment of the recline mechanism's coupler.

FIG. 11 is a side view showing the recline mechanism's coupler coupled to the recline mechanism's elastomeric spring assembly.

FIG. 12 is a front perspective view showing the recline mechanism's coupler coupled to the recline mechanism's elastomeric spring assembly.

IV. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

Referring to FIGS. 1-4, the reclinable chair 1 comprises a recline mechanism 300 pivotally attaching a backrest 200 to a support assembly 100. The support assembly 100 can comprise a seat 150 mounted to a base 110. The seat can comprise a seat cushion 151 attached to a seat shell 152. The recline mechanism 300 comprises a coupler 320 coupled to an elastomeric spring assembly 330.
The backrest 200 is attached to the support assembly 100 by mounting the coupler 320 to the elastomeric spring assembly 330 and then securing the coupler 320 to the seat 150 and/or the base 110. The coupler 320 can comprise an arm 321 attached to a cup 322. The distal side of the cup 322 is mated to the spring assembly 330 as described in further detail below. The proximal side of the cup 322 is secured to the seat 150 via one or more screws inserted through the cup's one or more holes 329. The coupler 320 is secured to the base 110 by sliding the coupler's arm 321 inside the end of the base 110. One skilled in the art will appreciate that a variety of fasteners can be used to attached the coupler 320 to either the seat 150 or the base 110, including bolts, screws, rivits, glue, or welding. Further, one skilled in the art will appreciate that the base 110 can be a pedestal base, a four-legged base, or any other base suitable for supporting a seat surface. In such embodiments, the coupler 320 can merely comprise the cup 322, thereby disposing of the coupler's arm 321.
An exploded view of the elastomeric spring assembly 330 is depicted in FIG. 5. The elastomeric spring assembly comprises four elastomeric (rubber) inserts 333 positioned between a polygon-shaped core 334 and a polygon-shaped exterior housing 331. The core 334 is rotated 45 degrees relative to the exterior housing 331. The inserts 333 are arranged in the corners of the exterior housing 331 and each bears on a face of the core 334. In this arrangement, any rotation of the exterior housing 331 with respect to the core 334 (or conversely, rotation of the core 334 with respect to the exterior housing 331) produces deformation of the elastomeric inserts 333. The deformation of the elastomeric inserts 333 allows for a torsional range of approximately ±30 degrees. The spring assembly's exterior housing 331 features one or more primary teeth 331 a extending from its outer periphery. The exterior housing 331 can also feature one or more secondary teeth 331 b extending from its outer periphery. In a preferred embodiment, the exterior housing 331 is twenty-five millimeters (25 mm) in length and has four primary teeth 331 a and eight secondary teeth 331 b.
Referring to FIGS. 6-8, the elastomeric spring assembly 330 can be secured to the backrest 200 via a sleeve 210. The sleeve 210 features one or more primary notches 210 a along its inner periphery which mate with the one or more primary teeth 331 a of the spring assembly's exterior housing 331. The sleeve 210 may also have one or more secondary notches 210 b along its inner periphery for mating with the exterior housing's secondary teeth 331 b. The sleeve 210 can be mounted to the backrest by inserting the sleeve 210 into the backrest's circular casing 201 and securing it thereto by any conventional means known in the art. In an alternative embodiment, the sleeve 210 can be integrally formed within the backrest 200, thereby allowing the elastomeric spring assembly's exterior housing 331 to be mounted directly to the backrest 200.
Referring to FIGS. 9-12, the coupler 320 is mounted to the elastomeric spring assembly 330 as follows. The distal side of the cup 322 can comprise a central ring 323 having one or more projections 323 a. The one or more projections 323 a engage the one or more slots 334 a in the spring assembly's core 334 (see FIG. 6) to fix the spring assembly's core 334 relative to the coupler 320. The distal side of the cup 322 also features one or more inwardly-protruding preload stops 322 a spaced apart from one or more inwardly protruding recline stops 322 b. When assembled, each of the elastomeric spring assembly's primary teeth 331 a are positioned between a preload stop 322 a and a recline stop 322 b. This positioning allows for the recline mechanism 300 to be installed in a pretensioned state as described below, and further protects the spring assembly from extending beyond its maximum torsional range of ±30 degrees when the backrest is reclined.
To apply a preload to the recline mechanism 300, the core 334 is rotated in the opposite direction of recline (i.e., in a forward direction towards the seat) before the coupler 320 is mated to the spring assembly 330. Once the coupler 320 is mated to the spring assembly 330, the spring assembly's core 334 is prevented from discharging the preload because the core 334 is fixed relative to the coupler 320 due to the engagement of the coupler's one or more projections 323 a with the core's one or more slots 334 a. The spring assembly's exterior housing 331 is also prevented from discharging the preload due to the interaction of its one or more primary teeth 331 a with the one or more preload stops 322 a. As shown in FIGS. 11-12, each primary tooth 331 a will engage a preload stop 322 a when the chair is in a rested state, thereby preventing the exterior housing 331 from rotating counter-clockwise and discharging the torsional pretension.
The recline mechanism can be secured to the backrest 200 via a bolt axle 340 and a bushing 341 extending through the coupler's central bore 325 to engage the backrest insert 211. The backrest insert 211 (See FIG. 6) can be fixedly attached to the central opening of the sleeve 210 or directly to the backrest 200 by any conventional fastening means known in the art. Alternatively, the backrest insert 211 can be formed as an intergral component of either the sleeve 210 or the backrest 200.
In operation, a user can recline the chair of the present invention by exerting a rearward force on the backrest 200. The spring assembly's exterior housing 331 is mated to the sleeve 210, which in turn is fixedly attached to the backrest 200. Thus, the torque produced by the application of a rearward force to the backrest is transmitted to the spring assembly's exterior housing 331, causing the spring assembly's exterior housing 331 to rotate about the spring assembly's core 334 in the direction of recline (i.e., in a rearward direction away the seat). The rotation of the exterior housing 331 about the core 334 produces deformation of the elastomeric inserts 333, with the resultant counterbalancing torque produced by the spring assembly 330 increasing in a progressive fashion as the backrest 200 is reclined. The chair will recline until the spring assembly's primary tooth 331 a engages the coupler's recline stop 322 b. The interaction of the spring assembly's tooth 331 a with the coupler's recline stop 322 b prevents the spring assembly from extending beyond its maximum torsional range of ±30 degrees, thereby increasing the service life of the recline mechanism 300. Once the rearward force applied by the user ceases, the elastomeric spring assembly 330 will unload and return the chair to the upright position.
In a preferred embodiment, 18 degrees of preload is applied to the spring assembly, resulting in each recline mechanism providing approximately 17 ft-lbs of torque when the chair is in the rested state. In the preferred embodiment, the recline stop 322 b is spaced apart from the preload stop 322 a a sufficient distance to allow for 12 degrees of motion. Over this range, the torque provided by each recline mechanism 300 will progressively increase in a generally linear fashion from approximately 17 ft-lbs of torque at rest to approximately 35 ft-lbs of torque at full recline. Thus, the recline mechanism will apply a progressively increasing resistance force as the user reclines in order to counterbalance the increase in load supported by the back of the chair.
Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teaching presented in the foregoing descriptions and the associated drawings. For instance, in FIGS. 1-12, the recline mechanism 300 is shown pivotally attaching the backrest 200 to both the seat 150 and the base 110. However, one skilled in the art will appreciate that the reclinable chair disclosed herein could be modified such that the recline mechanism 300 pivotally attaches the backrest 200 to either the base 110 or the seat 150. As for another example, the elastomeric spring assembly is depicted in FIGS. 1-12 as comprising four elastomeric inserts positioned between a generally square core 334 and a generally square exterior housing 331. However, one skilled in the art will appreciate that both the core and exterior housing could take the form of various other polygon shapes. Further, one skilled in the art will appreciate that various degrees of preload may be desired depending on the type of chair, the size of the recline mechanism, and/or the desired range of recline. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A reclinable chair, comprising:

a. a support assembly;

b. a backrest;

c. a recline mechanism pivotally attaching the backrest to the support assembly, the recline mechanism comprising:

i. An elastomeric spring assembly comprising at least four elastomeric inserts positioned between a polygon-shaped core and a polygon-shaped exterior housing, the exterior housing comprising an outwardly protruding primary tooth; and

ii. A coupler comprising an inwardly protruding preload stop spaced apart from an inwardly protruding recline stop, wherein the coupler is coupled to the elastomeric spring assembly such that the exterior housing's primary tooth is positioned between the preload stop and the recline stop.

2. The reclinable chair of claim 1, wherein the support assembly comprises a seat attached to a base.

3. The chair of claim 2, wherein the coupler is attached to the seat.

4. The chair of claim 2, wherein the coupler is attached to the base.

5. The reclinable chair of claim 1, wherein the coupler comprises an arm fixed to a cup, the cup defining a proximate side and a distal side, wherein the arm is attached to the base and the proximate side of the cup is attached to the seat.

6. The reclinable chair of claim 1, wherein the preload stop is spaced apart from the recline stop a sufficient distance to allow for the exterior housing to rotate about the core ±12 degrees.

7. The reclinable chair of claim 6, wherein the exterior housing is approximately twenty-five millimeters in length.

8. The reclinable chair of claim 1, further comprising a sleeve for mounting the elastomeric spring assembly to the backrest.

9. The reclinable chair of claim 8, wherein the sleeve comprises an inner periphery and an outer periphery, wherein the outer periphery is attached to the backrest, and wherein the inner periphery comprises a primary notch for mating with the exterior housing's primary tooth.

10. The reclinable chair of claim 8, wherein the exterior housing comprises a plurality of outwardly protruding primary teeth spaced apart from a plurality of outwardly protruding secondary teeth.

11. The reclinable chair of claim 10, wherein the sleeve comprises an inner periphery and an outer periphery, wherein the sleeve's outer periphery is attached to the backrest, and wherein the sleeve's inner periphery comprises a plurality of primary notches for mating with the exterior housing's plurality of outwardly protruding primary teeth, and wherein the sleeve's inner periphery comprises a plurality of secondary notches for mating with the exterior housing's plurality of outwardly protruding secondary teeth.

12. The reclinable chair of claim 8, wherein the backrest comprises a circular casing.

13. The reclinable chair of claim 12, wherein the sleeve comprises an inner periphery and an outer periphery, wherein the outer periphery is mounted within the backrest's circular casing, and wherein the inner periphery comprises a primary notch for mating with the exterior housing's primary tooth.

14. The reclinable chair of claim 1, wherein the backrest further comprises a sleeve having an inner periphery, the inner periphery comprising a primary notch for mating with the exterior housing's primary tooth.

15. The reclinable chair of claim 1, wherein the exterior housing comprises a plurality of outwardly protruding primary teeth spaced apart from a plurality of outwardly protruding secondary teeth.

16. The reclinable chair of claim 15, wherein the backrest further comprises a sleeve having an inner periphery, the inner periphery comprising a plurality of primary notches for mating with the exterior housing's plurality of outwardly protruding primary teeth, and wherein the sleeve's inner periphery comprises a plurality of secondary notches for mating with the exterior housing's plurality of outwardly protruding secondary teeth.

17. The reclinable chair of claim 1, wherein the elastomeric spring assembly's core further comprises a central bore having one or more slots extending therefrom.

18. The reclinable chair of claim 17, wherein the coupler further comprises a central ring having one or more projections mated to the core's one or more slots to fix the core to the coupler.

19. A reclinable chair, comprising:

a. a support assembly;

b. a backrest;

c. a recline mechanism, comprising:

i. A coupler attached to the support assembly, the coupler defining a cup, the cup comprising an inwardly protruding preload stop spaced apart from an inwardly protruding recline stop; and

ii. An elastomeric spring assembly positioned at least partially within the coupler's cup, the elastomeric spring assembly comprising at least four elastomeric inserts positioned between a polygon-shaped core and a polygon-shaped exterior housing, wherein the core is fixed to the coupler and the exterior housing is fixed to the backrest, and wherein the exterior housing comprising an outwardly protruding primary tooth positioned between the preload stop and the recline stop such that the primary tooth engages the preload stop when the chair is in a rested state and engages the recline stop when the chair is in a fully reclined state.

20. A reclinable chair, comprising:

a. a support assembly;

b. a backrest;

c. a recline mechanism, comprising:

i. An elastomeric spring assembly comprising at least four elastomeric inserts positioned between a polygon-shaped core and a polygon-shaped exterior housing, the core comprising a central bore having one or more slots extending therefrom, the exterior housing attached to the backrest and comprising an outwardly protruding primary tooth; and

ii. A coupler defining a proximate side and a distal side, the proximate side attached to the support assembly, the distal side comprising a central ring having one or more projections mated to the core's one or more slots, the distal side further comprising an inwardly protruding preload stop spaced apart from an inwardly protruding recline stop, wherein the exterior housing's primary tooth is positioned between the preload stop and recline stop.