The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed:-

FIELD OF INVENTION

[0001] The present invention relates to support structures for providing seating arrangements and more particularly to recliner type of support structures.

BACKGROUND OF THE INVENTION

[0002] Use of recliners in automotive vehicles for controlling seating position depending upon user preference is known. Conventionally  the seat recliners comprise a cam which is operably coupled to a shaft which actuates the rotation of the cam when manually driven by a lever attached to it. The cam comprises a plurality of sectors and is configured to slidably move the sectors in radial direction between a locked and an unlocked position. Outer portion of each of the sectors are lined with plurality of teeth. The teeth provided in the sectors are configured to engage with inner teeth of an upper part of the recliner in order to lock the seat position. Further  when the lever is operated  the cam and subsequently the sectors are moved from a locked to an unlocked position  and the teeth on the outer portion of the sectors are no longer interlocked with the inner teeth of the upper part  thus allowing the seat adjustment.

[0003] One limitation associated with the seat recliners of the type described above is the occurrence of operational noise and wear tear during the release of the outer teeth of the sectors from the inner teeth of the upper part. The locked position is achieved due to the intersection of the outer teeth of the sector with inner teeth of the upper part. The noise may be generated during the release of the sectors from a locked position to an unlocked position  as both the inner teeth and the outer teeth have uniform teeth profile. Hence  there is a need for an improved locking mechanism for controlling the operation of recliners.

BRIEF DESCRIPTION OF THE INVENTION

[0004] The above-mentioned shortcomings  disadvantages and problems are addressed herein which will be understood by reading and understanding the following specification.

[0005] The object of the present invention is to provide an improved locking mechanism that reduces noise generated during recliner operation.

[0006] Accordingly  in one embodiment  a locking mechanism is provided for a flexible support structure. The locking mechanism comprises a pair of recliners coupled to each other using a connecting rod. The pair of recliners is configured for coupling a seating unit with a support unit so as to facilitate motion between the support unit and the seating unit thereby providing the flexible support structure with a reclining range.

[0007] The locking mechanism further comprises a lever coupled to the connecting rod and configured to be operated by a user of the flexible support structure. Further  each of the recliners comprises a housing formed by a first part  and a second part coupled to the first part using a cover ring. The housing comprises a cam configured for bi-directional motion in an approximate semi circular path  a shaft coupled to the lever and the cam  such that motion induced in the lever rotates the shaft so as to actuate rotation of the cam.
The housing further comprises at least three sectors mounted on the cam  each sector being configured for sliding radially between a locking and an unlocking position. Further  the outer surface of each of the sectors comprise gear teeth such that the profile of the gear teeth positioned on each of the sectors are non-uniform. The second part of the housing comprises an annular rim of teeth lined on the internal wall diameter that operate in conjunction with the gear teeth of the sectors in order to set an accurate locking position.

[0008] In another embodiment  a flexible support structure is provided which comprises a seating unit and a support unit coupled to the seating unit through a pair of recliners. The pair of recliners are connected by a connecting rod. A lever is coupled to the connecting rod and is configured to be operated by a user of the flexible support structure. Further  each pair of recliners comprises a first part and a second part  the second part being coupled to the first part using a cover ring and thereby forming the recliner. The first part forms a part of the seating unit and comprises a cam configured for bi-directional motion in an approximate semi circular path  a shaft coupled to the lever and the cam  such that a motion induced in the lever rotates the shaft so as to actuate rotation of the cam. At least three sectors are mounted on the cam  each sector being configured for sliding radially between a locked position and an unlocked position. The outer surface of each of the sectors comprise gear teeth and the profile of the gear teeth positioned on each of the sectors are non-uniform in order.to facilitate setting an accurate locked position. The second part is coupled to the support unit and is lined with an annular rim of teeth in the internal wall diameter that operate in conjunction with the gear teeth of the sectors for facilitating motion between a locked position and an unlocked position of the support unit with respect to the seating unit so as to provide the flexible support structure with a reclining range.

[0009] Systems and methods of varying scope are described herein. In addition to the aspects and advantages described in this summary  further aspects and advantages will become apparent by reference to the drawings and with reference to the detailed description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1a shows a schematic diagram of a flexible support structure having a support unit and a seating unit as described in one embodiment;

[0011] FIG. 1b shows a schematic diagram of a flexible support structure having a support unit and a seating unit coupled to each other by two recliners as described in one embodiment;

[0012] FIG. 1c shows a schematic diagram of a flexible support structure having a recliner at one end and a hinge at other end;

[0013] FIG.2 shows a schematic diagram of a locking mechanism employed in the flexible support structure as described in one embodiment;

[0014] FIG. 3 shows a schematic diagram of the top view of the locking mechanism in a locked position as described in one embodiment;

[0015] FIG. 4 shows a schematic diagram of the top view of the locking mechanism in an unlocked position as described in one embodiment;

[0016] FIG.5 shows a schematic diagram of the sectors having gear teeth at the outer surface as described in one embodiment;

[0017] FIG.6 shows a schematic diagram of the sectors having non-uniform teeth profile as described in one embodiment;

[0018] FIG. 7 shows a cover ring having a discontinuous periphery as described in one embodiment; and

[0019] FIG. 8 shows a schematic diagram of the locking mechanism having a cover ring having cutout portions and welded at the edges.

DETAILED DESCRIPTION OF THE INVENTION

[0020] In the following detailed description  reference is made to the accompanying drawings that form a part hereof  and in which is shown by way of illustration specific embodiments  which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments  and it is to be understood that other embodiments may be utilized and that logical  mechanical  electrical and other changes may be made without departing from the scope of the embodiments. The following detailed description is  therefore  not to be taken in a limiting sense.

[0021] To substantially eliminate the noise caused while operating a locking mechanism using a lever  the locking mechanism is provided with multiple sectors having gear teeth with non-uniform profile on their outer surface. The sectors having non-uniform teeth profile are engaged with teeth lined on internal wall of a second part  such that during the operation of the locking mechanism  the noise produced can be avoided/reduced.

[0022] FIG.1a and FIG. 1b show a flexible support structure 100 comprising a seating unit 102 and a support unit 104 connected pivotally to the seating unit 102  allowing adjustment of the support unit 104 relative to the seating unit 102 between recline range (a-b). The seating unit 102 and the support unit 104 are connected by two recliners 106 and 107 on either side. The recliners 106 and 107 are coupled to each other by a connecting rod 108. The connecting rod 108 is coupled to a lever 110 that is operated by a user of the flexible support structure 100.

[0023] In an alternative embodiment  the seating unit 102 and the support unit 104 are connected by single recliner 106 at one end and a hinge 112 at other end as shown in FIG. 1c. The recliner 106 is coupled to the lever 110 that is operated by the user of the flexible support structure 100. In one embodiment  the flexible support structure 100 includes any support structure that is movable in order to support a human being. More particularly  the flexible support structure 100 includes a seating structure  a seating structure used in automotives  prams  hospital cots  surgical tables  positioning devices  patient positioning devices  dental chairs and such structures that are flexible and support positioning human beings.

[0024] FIG.2 shows a locking mechanism 200 employed in the flexible support structure 100. The locking mechanism 200 comprises a first part 202 and a second part 204 coupled to the first part 202 using a cover ring 206. In one embodiment  the first part 202 forms a part of the seating unit 102. The following description is explained in conjunction with FIG.1 and FIG.2. The first part 202 comprises a shaft 208 that is manually adjusted by the lever 110. A cam 210 is operably coupled to the shaft 208 and is configured for bi-directional rotation in an approximate semi-circular path. The rotation of the cam 210 is actuated by the shaft 208. A plurality of sectors 212 are movably coupled to the cam 210 and are configured to slide radially when rotation of the cam 210 is actuated by the shaft 208. Each of the sectors 212 are mounted to slide radially between a locked and an unlocked position.

[0025] In one embodiment  the locking mechanism 200 comprises three sectors 212 which are disposed at approximately 120 degrees to each other about a vertical axis  so as to enable a self-centering mechanism. The first part 202 further comprises a spring unit 224 configured for coupling the cam 210 with at least one of the sectors 212  so as to station the cam 210 in a locked position.

[0026] The second part 204 forms a part of the support unit 104. The second part 204 comprises an annular rim of teeth 214 in the internal wall diameter. For locking the support unit 104 at any given position  the lever 110 is operated to control movement of the shaft 208  which in turn controls the rotation of the cam 210. Subsequently  the sectors 212 are slided radially towards the annular rim of teeth 214 lined on the internal wall diameter of the second part 204. In a locked position  the gear teeth 216 of the sectors 212 engage with inner teeth 214 of the second part 204  thus preventing the motion of the support unit 104 with respect to the seating unit 102.

[0027] On the contrary in an unlocked position  the gear teeth 216 of the sectors 212 disengage with the inner teeth 214 of the second part 204 in order to facilitate the motion of the support unit 104 with respect to the seating unit 102 thereby providing a reclining range (a-b).

[0028] The engagement and disengagement of the sectors 212 with the second part 204 depends upon rotation and counter rotation of the cam 210 and which in turn is initiated by the operation of the lever 110. The first part 202 further comprises a guide plate 218 that is coupled to the cam 210 and the sectors 212. The sectors 212 further comprise at least one projection 220 on each of its surface to operably engage the guide plate 218. The guide plate 218 comprises multiple grooves 222 in which the projections 220 of the sectors 212 are engaged. The guide plate 218 is mounted on the cam 210 and extends radially between the cam 210 and the second part 204 partially overlying the sectors 212.

[0029] For engaging the sectors 212 with the second part 204  the cam 210 is actuated to rotate by operating the lever 110. The rotation of the cam 210 engages the guide plate 218 consequently  the guide plate 218 rotates and the grooves 222 in which the projections 220 on the sectors are engaged actuate the sectors 212 to slide radially. The sectors 212 slide and engage with the inner teeth 214 of the second part 204. Further  for disengaging the sectors 212 with the second part 204  the lever 110 is released resulting in counter rotation of the cam 210. The cam 210 counter rotates along with guide plate 218  and subsequently  the grooves 222 engage with the projections 220 on the sectors 212 resulting in sliding of the sectors 212 away from the inner teeth 214 of the second part 204.

[0030] Further  the sectors 212 are positioned at locked position when not being operated. The spring unit 224 is configured for coupling the cam 210 with the sectors 212 so as to station the sectors 212 in locked position. Upon actuating the cam 210 by operating the lever 110 to position the support unit 104 according to user preference  the sectors 212 slide down thereby disengaging with the second part 204. Following an action by the user that releases the lever 110  at a desired position in the recliner range (a-b)  the sectors 212 slide radially and engage with the inner teeth 214 of the second part 204.

[0031] In operation  the gear teeth 216 on the outer surface of the sectors 212 are locked on to the annular rim of teeth 214 of the second part 204 thus locking the angular position of the support unit 104 relative to the seating unit 102. FIG.3 shows the locking mechanism 200 in a locked position. When the lever 110 is operated from the locked position to an unlocked position  the gear teeth 216 on the sectors 212 are no longer interlocked with the annular rim of teeth 214 of the internal wall of the second part 204  thus allowing the motion of the support unit 104 with respect to the seating unit 102. FIG. 4 shows the locking mechanism 200 in an unlocked position. As is shown in FIG. 4  the sectors 212 are positioned away from the second part 204.

[0032] As mentioned in the prior embodiments  the sectors 212 are positioned approximately equi-angle from each other and operate on a self centering mechanism. The present invention has been illustrated with three sectors 212. However  it is apparent to those skilled in the art that the recliner 106 may be re-configured to include at least two or more sectors wherein the sectors are equally spaced circumferentially and corresponding number of sector engaging surfaces are provided on the cam. FIG. 5 shows each of the sectors 212 being lined with gear teeth 216 on the outer surface.

[0033] Further  the gear teeth 216 on each of the sectors 212 have a non-uniform profile as shown in FIG. 6. The gear teeth 216 on each of the sectors 212 may be divided into a first edge teeth 226  a center part teeth 228 and a second edge teeth 230. The profile of the gear teeth 216 on each of the edge parts is different from the profile of the gear teeth 216 on the center part teeth 228. The profile of the gear teeth 216 is truncated towards the edges 226 and 230 and hence the profile of the gear teeth 216 on the edges decreases in height on a path away from the center of the sector 212. Such profile of the gear teeth 216 facilitates accurate locking of the gear teeth 216 with the inner teeth 214 of the second part 204 resulting in reduction of noise caused while operating the locking mechanism 200. Accordingly  the advantage of the invention includes an improved arrangement for reducing noise in a recliner locking mechanism.

[0034] In one embodiment  the cover ring 206 configured for coupling the first part 202 with the second part 204 in each of the recliners 106 and 107 comprises a discontinuous diametric profile. The cover ring 206 comprises multiple (preferably three) cutout portions 232 as shown in FIG. 7. Further the cutout portions 232 are welded at their edges 234 for providing better strength and to reduce weight of the recliners 106 and 107 shown in FIG. 8.

[0035] In an alternative embodiment  the connecting rod 108 may be directly coupled with the cam 210 thereby eliminating the need for the inclusion of the shaft 208. Accordingly  the invention describes a flexible support structure 100 comprising the seating unit 102  the support unit 104  recliners 106 and 107  each recliner 106 and 107 having a first part 202 and a second part 204. The first part 202 comprises a connecting rod 108 that is manually adjusted by the lever 110. The cam 210 is operably coupled to the connecting rod 108 and is configured for bi-directional rotation in an approximate semi-circular path. The rotation of the cam 210 is actuated by the connecting rod 108. The sectors 212 are movably coupled to the cam 210 and are configured to slide radially when rotation of the cam 210 is actuated by the connecting rod 108.In various embodiments of the invention  a locking mechanism 200 for a flexible support structure 100 and a flexible support structure 100 using the locking mechanism 200 are described. However  the embodiments are not limited and may be implemented in connection with different applications. The application of the invention can be extended to other areas  for example positioning devices. The invention provides a broad concept of using a variable teeth profile in sectors for facilitating accurate locking mechanism  which can be adapted in a similar positioning system. The design can be carried further and implemented in various forms and specifications.

[0036] This written description uses examples to describe the subject matter herein  including the best mode  and also to enable any person skilled in the art to make and use the subject matter. The patentable scope of the subject matter is defined by the claims  and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims  or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

CLAIMS

What is claimed is:
1. A locking mechanism for a flexible support structure  the locking mechanism comprising:
a pair of recliners coupled to each other using a connecting rod  the pair of recliners configured for coupling a seating unit with a support unit so as to facilitate motion between the support unit and the seating unit thereby providing the flexible support structure with a reclining range;
a lever coupled to the connecting rod and configured to be operated by a user of the flexible support structure;
each of the recliners comprising a housing formed by a first part  and a second part coupled to the first part using a cover ring  the housing comprising:
a cam configured for bi-directional motion in an approximate semi circular path;
a shaft coupled to the lever and the cam such that motion induced in the lever rotates the shaft so as to actuate rotation of the cam;
at least three sectors mounted on the cam  each sector being configured for sliding radially between a locking and an unlocking position and wherein the outer surface of each of the sectors comprise gear teeth; and
the second part comprising an annular rim of teeth lined on the internal wall diameter that operate in conjunction with the gear teeth of the sectors in order to set an accurate locking position;
characterized in that the gear teeth positioned on each of the sectors are non- uniform.

2. The locking mechanism of claim 1  wherein the sectors are positioned approximately at equal angle from each other and operate on a self centering mechanism.

3. The locking mechanism of claim 1  wherein gear teeth on each sector are divided into first edge part  a center part and a second edge part and profile of the gear teeth on the edge parts is different from the profile of the gear teeth at the center part.

4. The locking mechanism of claim 3  wherein profile of the gear teeth at the edges is truncated on a path away from the center  for aiding in setting an accurate locking position.

5. The locking mechanism of claim 1  wherein the housing further comprises a guide plate coupled to the cam such that the cam controls the motion of the guide plate that in turn controls the sliding of the three sectors.

6. The locking mechanism of claim 1  wherein the housing further comprises a spring unit configured for stationing the cam in a locked position.

7. The locking mechanism of claim 1  wherein the outer diameter of the cover ring is discontinuous.

8. A flexible support structure comprising:
a seating unit comprising a pair of recliners connected by a connecting rod; a lever coupled to the connecting rod and configured to be operated by a user of the flexible support structure; each pair of recliners comprising a first part and a second part  the first part forming a part of the seating unit and comprising:
a cam configured for bi-directional motion in an approximate semi circular path;
a shaft coupled to the lever and the cam such that a motion induced in the lever rotates the shaft so as to actuate rotation of the cam;
at least three sectors mounted on the cam  each sector being configured for sliding radially between a locking and an unlocking position and wherein the outer surface of each of the sectors comprise gear teeth to facilitate setting an accurate locked position; and
a support unit coupled to the seating unit through the pair of recliners  the support unit comprising the second part coupled to the first part using a cover ring and thereby forming the recliner  the second part being lined with an annular rim of teeth in the internal wall diameter that operate in conjunction with the gear teeth of the sectors for facilitating motion between locking and unlocking position of the support unit with respect to the seating unit so as to provide the flexible support structure with a reclining range;
characterized in that the gear teeth positioned on each of the sectors are non- uniform.

9. The flexible support structure of claim 8  wherein the sectors are positioned approximately at equal angle from each other and operate on a self centering mechanism.

10. The flexible support structure of claim 8  wherein gear teeth on each sector are divided into first edge part  a center part and a second edge part and profile of the gear teeth on the edge parts is different from the profile of the gear teeth at the center part.

11. The flexible support structure of claim 10  wherein profile of the gear teeth at the edges decreases in height on a path away from the center.

12. The flexible support structure of claim 8  wherein the first part further comprises a guide plate coupled to the cam such that the cam controls the motion of the guide plate which in turn controls the sliding of the three sectors to ensure appropriate engagement of the gear teeth of the three sectors with the annular rim of teeth in the second part.

13. The flexible support structure of claim 8  wherein the first part further comprises a spring unit configured for stationing the cam in a locked position  the spring unit extending between a first end connected to the one of the sectors and a second end connected to the cam.

14. The flexible support structure of claim 8  wherein the outer diameter of the cover ring is discontinuous.

15. A recliner for a flexible support structure  the recliner comprising a housing formed by a first part  and a second part coupled to the first part using a cover ring  characterized in that the outer diameter of the cover ring is discontinuous.