WO2001047744A1

WO2001047744A1 - Recliner mechanism with brake action

Info

Publication number: WO2001047744A1
Application number: PCT/SE2000/002525
Authority: WO
Inventors: Lennart Lindblad
Original assignee: Lennart Lindblad
Priority date: 1999-12-23
Filing date: 2000-12-14
Publication date: 2001-07-05
Also published as: SE9904759D0; AU2416801A; SE515219C2; SE9904759L

Abstract

The invention concerns a device for adjustment of the relative angular positions between a first pivot element (20) and a second pivot element (21), said elements preferably located on the seat cushion (2) and the backrest (3), respectively, of for example a chair (1) or a vehicle seat. The pivot elements (20, 21) are arranged for pivotal movement about a common axis relative to which axis ring gears (25a, 25b) are arranged in an essentially centred position. The device further comprises at least one toothed wheel (23) meshing with said ring gears and being movable alont the circumference of the respective ring gear (25a, 25b) in response to rotation of said toothed wheel (23). The device also comprises a support element (22) formed with slide and friction faces, which circumscribe the toothed wheel (23) along at least part of the wheel circumference. In addition, the support element (22) is coupled to a control means (4). The support element (22) and the toothed wheel (13) are arranged to be pressed against one another, whereby the support element (22), upon adjustment of the angular position of the device, is urged against the toothed wheel (23) so as to exert driving pressure thereon and whereby the toothed wheel (23), upon torque loads on the device, is pressed against the support element (22).

Description

REC INER MECHANISM WITH BRAKE ACTION

Technical Field

The present invention relates to a device for adjustment of the relative angular positions between a first pivot element and a second pivot element, said elements preferably located on the seat cushion and the backrest, respectively, of for example a chair or a vehicle seat. Furthermore, these pivot elements are arranged for pivotal movement about a common axis rela- tive to which axis first and second ring gears are arranged in an essentially centred position on the respective one of said pivot elements. The device further comprises at least one toothed wheel meshing with said ring gears and being movable along the periphery of the respective ring gear in response to rotation of said toothed wheel .

Background of the Art

Devices for adjustment of the relative angular posi- tions between a seat cushion and a backrest usually is referred to collectively as recliner mechanisms or angular adjustment means. Numerous recliner mechanisms of the kind defined in the introduction are already known, among them various planetary gear arrangements intended for in- stance for vehicle seats. A drawback found in many of these arrangements is, however that on account of their high transmission gear ratio the control wheel must often be rotated over a large number of turns to achieve the desired angular-position change. In addition, separate blocking means have to be provided in order to prevent unwanted angular-position changes as a result of heavy- torque load on for instance the backrest relative to the seat cushion, for instance in case of collisions. In addition, more and more frequently wishes are voiced within the motor industry for the possibility to mount seat belt structures on the vehicle seat rather than on the inner face of the vehicle body, as is common practice. Being able to mount the belt on the seat would be advantageous, among other things for the reason that the vertical adjustment of the point of attachment of the belt, necessary today to allow individuals of different heights to be strapped to the seat, would no longer be needed. However, mounting of the belt on the seat adds to the stress on the recliner mechanism in case of collisions, and consequently very strong and sturdy blocking mechanisms are required in order to prevent angular-position changes in case of a collision. In addition, the control, which is coupled to the recliner mechanism, often is badly positioned, as it is inserted in the narrow space between the lower part of the seat and the side wall of the vehicle, which makes the adjustment operation additionally inconvenient. Consequently, there is a need for an adjustment mechanism, which is easy to operate and which is designed with a comparatively low transmission gear ratio while at the same time offering an efficient and safe blocking function. Also in other application, such as in office furniture and the like, there is a corresponding need for angular-position mechanisms that are easy to operate.

Object of the Invention

The object of the invention thus is to provide a recliner mechanism, which is easy to adjust but which effi- ciently blocks the parts in the adjusted position when exposed to load.

Summary of the Invention

This object is achieved in accordance with the in- vention in that the device also comprises a support element formed with slide and friction faces, which circum- scribe the toothed wheel along at least part of the wheel circumference, said support element being coupled to a control means, and in that the support element and the toothed wheel are arranged to be pressed against one another, whereby the support element, upon adjustment of the angular position of the device, is urged against the toothed wheel so as to exert driving pressure thereon and whereby the toothed wheel, upon torque loads on the device, is pressed against the support element. Under non-load conditions, the toothed wheel thus is free to move both along the circumference of the ring gear and in some cases also in the radial direction relative to the ring gear, and consequently it is easily movable. Upon actuation of the control means, the support element brings along the toothed wheel, the latter thus rotating along the circumference of the ring gear. Upon torque load on the pivot elements, the ring gears will, however, turn in mutually opposite directions, thus urging the freely supported toothed wheel in a radial direction in- wards, whereby the toothed wheel will be pressed against the support element and thus provide efficient blocking of the parts. In case of stronger torque forces, the blocking force thus generated will increase.

In accordance with a preferred embodiment, the above-mentioned toothed wheel is of double type comprising two toothed wheels having mutually different radii, and the ring gears have different diameters. As a result, gearing motions will take place with a minimum of wear on the mechanical parts involved. In accordance with a further preferred embodiment, the support element is arranged to slide in abutment against the tooth crests of the first as well as of the second ring gear, with consequential added mechanical structural stability. In addition, said supports preferably are movable relative to the pivot elements in the angular as well as in the radial directions and they occupy essentially the entire space of extension of the gear ring defined by the tooth crests, with recesses for accommodation of said toothed wheels. Also this feature results in a more stable mechanical structure and ensures small movements of the toothed wheels and the support elements, respectively, upon blocking of the device.

Finally, said control means preferably comprises a control knob mounted to one side of the first pivot element, an abutment plate mounted on the opposite side of the second pivot element and sandwiched therebetween, interconnecting means, which are non-rotationally connected with the support means. Owing to this arrangement, the recliner mechanism is easy to operate by actuating of the control knob, the support means, as a result of abut- ment, urging the toothed wheels to rotate along the ring gear.

Brief Description of the Drawings

The invention will be described in the following with respect to preferred embodiments and with reference to the accompanying drawings, wherein

Fig 1 is a plan view showing the position of a recliner mechanism in accordance with the invention between the backrest and the seat cushion, Fig 2a is a plan view of a first pivot element in accordance with a first embodiment, also showing the associated toothed wheel and the support element,

Fig 2b is a plan view of a second pivot element in accordance with the embodiment of Fig 2a, also showing the associated toothed wheel and the support element,

Fig 2c is a plan view of the first pivot element in accordance with the embodiment of Fig 2a and the second pivot element in accordance with Fig 2b together with associated co-operating toothed wheels and support ele- ment ,

Fig 3a is a lateral view of a first pivot element and a second pivot element in accordance with a second embodiment, together with the associated co-operating toothed wheels and support element,

Fig 3b is a plan view of the embodiment shown in Fig 3a, as seen in two different sectional views along lines I-I and II-II, respectively, and

Fig 4 is a view showing two recliner mechanisms in accordance with the invention, said mechanisms intended to be positioned on opposite sides of a chair and being interconnected by means of a uniting rod.

Detailed Description of Preferred Embodiments

Fig 1 is a general view of a chair 1 comprising a seat cushion 2 and a backrest 3. The recliner mechanism in accordance with the invention is placed in the articu- lated joint between the cushion and the backrest. The relative angular positions of the seat and the backrest are adjusted with the aid of a control knob wheel 4.

Figs 2a-2c show a first and a second pivot element 10 and 11, respectively, which are arranged to be mounted in pairs at the rear edge of the cushion and at the lower end of the backrest, respectively. In accordance with this embodiment, the pivot elements are flat plate-like elements. The first pivot element 10 is formed with a first ring gear 15a and the second pivot element 11 with a second ring gear 15b. When the pivot elements are mounted on the chair, they are positioned to ensure that the first and the second ring gear, 15a and 15b, respectively, are essentially centred relative to one another. In addition, the first and the second pivot ele- ment are mounted to ensure that the spacing between their respective flat faces is small, the object being to produce a space-efficient and compact structure. In accordance with this embodiment, the first ring gear 15a has a smaller diameter than the second ring gear 15b. In the opening, which in the mounted position of the two pivot elements is delimited by the two ring gears 15a and 15b, respectively, is inserted a toothed-wheel means 13a, 13b, said means being a double-wheel type of means comprising two toothed-wheel elements of mutually different radii. The first toothed-wheel element 13a is designed to travel along the sequence of teeth of the first ring gear 15a while the second toothed-wheel element 13b, having a larger radius than the first toothed-wheel element 13a, is designed to travel along the sequence of teeth of the second toothed-wheel element 15b. The first and second toothed-wheel elements are centred relative to one another and non-rotationally interconnected. In accordance with this embodiment the first toothed wheel also has a non-round opening, preferably formed with splines and adapted to non-rotationally receive a connection rod (not shown) , which couples the device to a corresponding device situated on the opposite side of the chair 1 for synchronised operation. In addition, a support element 12a, 12b is received in the opening defined by the ring gears 15a, 15b. This support element is formed with slide and friction faces, which are turned towards the tooth crests of the ring gears 15a, 15b and towards the second toothed wheel 13b. In this embodiment, the play between the support element and the above components is small. Via the through-connection rod 14, the support element 12a, 12b is connected to a control knob (not shown in this embodiment) .

Setting of the relative angular positions takes place when the device is in an unstressed position, i.e. when no force is applied on the backrest 3. Upon rotation of the control knob 4, which is connected to the support elements 12a, 12b via the through-coupling rod 14, the support element, which abuts against the toothed-wheel crests of the respective ring gears 15a, 15b and against the second toothed wheel 13b, brings along the second toothed wheel 13b and consequently the first toothed wheel, and said wheels are made to rotate along their respective one of the ring gears. As a result of the traditional transmission gear ratio, the relative angle be- tween the pivot elements 10 and 11 is increased or reduced, depending on the direction in which the control knob is rotated. To rotate the knob is easy, owing to the toothed wheels being freely supported. When on the other hand the device is exposed to torque load, the pivot elements are forced to move in mutually opposite directions, the double toothed wheel being affected by mutually opposite forces exerted by the first and the second ring gears, respectively. The double toothed wheel thus is urged radially inwards, in the direction of disengagement from the ring gears, because of the inclination of the flanks of the teeth, see Fig 2a, and is urged against the support element, which prevents the toothed wheels from rotating and thus disengage from the ring gears. In this manner, the device is locked in position. Heavier torque load only has the effect of increasing the forces acting on the toothed wheels with the generation of oppositely directed forces as a result. The embodiment shown in Figs 3a-3b is constructively similar to the one shown in Figs 2a-2c. Fig 3b shows first and second pivot elements, 20 and 21, respectively, which form a unit and which are arranged to be mounted in pairs at the rear edge of the seat cushion and at the lower edge of the backseat, respectively. In accordance with this embodiment, the pivot elements are designed as flat plate-like elements. A first ring gear 25a is formed in the first pivot element 20 and a second ring gear 25b is formed in the second pivot element 11. When mounted on the chair, the pivot elements are positioned in such a manner that the first and the second ring gear 25a and 25b, respectively, are essentially centred relative to one another. In addition, the first and the second pivot elements are mounted such that their respective flat faces are spaced only a small distance apart, see Fig 3a, in order to thus achieve a space-economic and compact structure. In accordance with this embodiment, the first ring gear wheel 25a has a diameter that is smaller than the diameter of the second ring gear 25b. In the opening, which in the mounted position of the pivot element is delimited by the two ring gears 25a and 25b, respectively, two essentially identical toothed wheel means are in- serted. These wheel means are of a two-wheel type, each means comprising two toothed-wheel elements 23a, 23b having mutually different radii. The first toothed-wheel element 23a is designed to travel along the teeth of the first ring gear 25a, and the second toothed wheel element 23b, having a larger radius than the first one 23a, is designed to travel along the teeth of the second ring gear 25b. The first and the second toothed wheel elements are centred in pairs relative to one another and are non- rotationally interconnected. In addition, a support ele- ment 22a, 22b is received in the opening defined by the ring gears 25a, 25b. The support element is formed with slide and friction faces turned towards the tooth crests and the ring gears 25a, 25b and towards the other two toothed wheels 23b. In accordance with this embodiment, the play between the support element and the above- mentioned components is small. Via through-coupling elements 24, this support element 22a, 22b is connected to an control knob (not shown in this embodiment) located at one side of the two pivot elements, and to a support plate 5 on the opposite side of the two pivot elements, see Fig 3a.

Also functionally, the embodiment illustrated in Figs 3a and 3b is equivalent to the one shown in Figs 2a- 2c. When the device is exposed to torque load oppositely directed pivotal forces are exerted on the pivot elements, such that the double toothed wheel is forced in opposite directions by the first and the second ring gear, respectively. The two double toothed wheels thus are urged radially inwards, in a direction of disengage- ment from the ring gears, as a result of the inclination of the flanks of the teeth, see Fig 3b, and they are thus pressed against the support element, the extension of the latter being such that the support element offers fric- tional resistance to and prevents the toothed wheels from disengaging from the ring gears. In this manner, the device is locked in its then position. More considerable torque load only results in stronger forces being exerted on the toothed wheels, the frictional effect thus becoming stronger. In addition, it should be mentioned that in use a connecting rod 30 (see Fig 4) often connects the device with a corresponding device provided at the opposite side of the chair 1.

Several modifications of the device are conceivable within the scope of protection of the appended claims. For example, the two ring gears could have diameters of equal size and the toothed wheel could be a uniform toothed wheel of constant diameter engaging the first as well as the second ring gear. In this case the number of teeth of the first and of the second ring gear must differ, and preferably be of different circular pitch in order to provide the desired relative turning movement of said components. In addition, the number of toothed wheels could exceed two and the support element could be configured in different ways and fill up the space defined by the gear rings and the toothed wheels to a smaller or larger extent.

Claims

1. A device for adjustment of the relative angular positions between a first pivot element (10, 20) and a second pivot element (11, 21), said elements preferably located on the seat cushion (2) and the backrest (3) , respectively, of for example a chair (1) or a vehicle seat, said pivot elements (10, 11; 20, 21) being arranged for pivotal movement about a common axis relative to which axis first and second ring gears (15a, 15b; 25a, 25b) are arranged in an essentially centred position on the respective one of said pivot elements, said device further comprising at least one toothed wheel (13; 23) meshing with said ring gears and being movable along the circum- ference of the respective ring gear (15a, 15b; 25a, 25b) in response to rotation of said toothed wheel (13; 23), c h a r a c t e r i s e d in that the device also comprises a support element (12; 22) formed with slide and friction faces, which circumscribe the toothed wheel (13; 23) along at least part of the wheel circumference, said support element (12; 22) being coupled to a control means (4), and in that the support element (12; 22) and the toothed wheel (13; 23) are arranged to be pressed against one another, whereby the support element (12; 22), upon adjustment of the angular position of the device, is urged against the toothed wheel (13; 23) so as to exert driving pressure thereon and whereby the toothed wheel (13; 23), upon torque loads on the device, is pressed against the support element (12; 22).

2. A device as claimed in claim 1, wherein said toothed wheel (13; 23) is of double type comprising two toothed wheels (13a, 13b; 23a, 23b) having mutually different radii, and the ring gears (15a, 15b; 25a, 25b) have mutually different diameters.

3. A device as claimed in claim 2, wherein the support element (12; 22) is arranged to slide in abutment against the tooth crests of the first as well as of the second ring gear (15a, 15b; 25a, 25b) .

4. A device as claimed in any one of the preceding claims, wherein said support elements (12; 22) preferably are movable relative to the pivot elements (10, 11; 20, 21) in the angular as well as in the radial directions and occupy essentially the entire space of extension of the gear rings ( (15a, 15b; 25a, 25b) defined by the tooth crests, with recesses for accommodation of said toothed wheels (13; 23) .

5. A device as claimed in any one of the preceding claims, wherein said control means (4) comprises a control knob (4) mounted to one side of the first pivot element (10; 20), an abutment plate (5) mounted on the oppo- site side of the second pivot element (11; 21) and sandwiched therebetween, interconnecting means (14; 24), which are non-rotationally connected with the driving means (12; 22) .