Multi Pivot Tilting Seat Support Structure

Abstract

An adjustable seat support structure for modifying the posture of a seated person with a dual tilt mechanism, which allows and supports both a forward inclining and a rearward reclining seating posture, includes a foundation base assembly, a height adjustable seat support column assembly, an adaptive seat support link positioned on the foundation base assembly and the height adjustable seat support column assembly, an adaptive and lockable dual ult mechanism supporting a pivotal seat assembly a dynamic moving seat support that facilitates a modulated pivotal motion through a transverse parallelepiped lever assembly, a seat assembly mounted to a top plate of the dynamic moving support structure having a bowl portion and a fabric cover, a backrest support portion, an armrest support portion mounted to a backrest, and a beadrest portion mounted to the back rest support portion by a j-bar.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is the United States national phase of International Patent Application No. PCT / TH2024 / 000002 filed Jan. 18, 2024, and claims priority to International Patent Application No. PCT / TH2023000011 filed May 2, 2023, the disclosures of which are hereby incorporated by reference in their entireties.BACKGROUNDField of the Disclosure

[0002] The present disclosure relates to a multi pivotal horizontal rotating seat support structure or device that is commonly used in office chairs to support the weight of a person, in particular a seated person, and specifically, to an adjustable support structure or device, that is adjustable to alter the seating or reclining position of a subject resting on the structure particularly from an inclined forward position to a rearward reclined position. The background of the disclosure will be described in the next section of this specification with specific reference to an office chair.Description of Related Art

[0003] There are imminent situations, where there is a need to provide an adjustable seating support structure. One of the best known, but not exclusive examples of this need, is in office and task chairs, where the posture of a seated person needs to be altered, in order to administer various tasks executed in a seated position. It also needs to be altered in terms of height, build and proportions of the seated person. Moreover, the person's seating or reclining position may need to be altered, to provide a higher seating position in tandem with a height adjustable table or desk, for example, as shown in U.S. Patent App. Pub. No. U.S.20120299350A1, U.S. Patent App. Pub. No. U.S.20090140567A1, Japan Patent App. Pub. No. JP2019013718A.

[0004] Support structures for use in offices and other situations, which allow altering the seat height, seat inclination and reclining position of a subject are known (e.g., U.S. Pat. No. 7,028,580A, International Patent App. Pub. No. WO01 / 8719Al, U.S. Pat. No. 9,356,998B1, U.S. Pat. No. 11,620,043B1, and U.S. Pat. No. 8,944,507B2). However, many of the known forms of support structures suffer from various disadvantages, such as by not acknowledging the latest status of biomechanical science or focusing only on some limited parts of the ergonomic implications of the seated person. Non-limiting embodiments of the present disclosure are primarily, but not exclusively, focused on an office and task chair application.

[0005] In some non-limiting embodiments, an office chair includes eight portions:

[0006] (A) A mobile base assembly portion (foot base)

[0007] (B) A pneumatic height adjustable swivel column (gas spring)

[0008] (C) An adjustable support structure portion (mechanism)

[0009] (D) A seat support portion (seat pan)

[0010] (E) An arm support portion (armrest)

[0011] (F) A spine support portion (backbone)

[0012] (G) A Backrest support portion (backrest)

[0013] (H) A head support portion (headrest)

[0014] Portion (A) supports the upper portions (B-H), may be equipped with glides or swiveling wheels for mobility while seated. Portion (B) contains a mechanical or pneumatic device to allow swiveling and a height adjustment of the upper portions (C-H). Portions (C) and (D) enable an articulated movement of a person from an inclined and forward leaning seated position to a lower backward reclined position, which can be secured infinitely by the use of a mechanical, pneumatic, or electric actuated means.

[0015] Portion (E) is attached to the height adjustable backrest (G) to maintain a constant equal and proportional correct height for the lower arm of a seated person.

[0016] Portion (F) is configured to support the portions G, E & H and is transverse pivotally hinged to portion (C) to allow for a reverse synchronized alteration of the backrest angle with the imaginative pivotal fulcrum in the hip joint.

[0017] Many known forms of support structures, upon which a user may be supported in a seated position, demonstrate limited knowledge of the current state of anthropological or biomechanical data, or purposely choose to focus only on parts of it. Exemplary deficiencies of known chairs are discussed hereinafter.

[0018] Despite current knowledge and scientific feet, the majority of chair manufacturers still follow an outdated rule of sitting on a horizontal surface upright at fixed 90-degree angles between leg, thigh and upper body (torso). Scientific evidence (Mandal, Keagan) shows, that the angle between the vertical axis of the pelvis and thighs at the hip joint can only bend 60 degrees; the remaining 30-degree bending is affected by commensurate rotation of the pelvis axis back-wards, which changes the natural curve of the spine (lordosis) into an opposite curve (kyphosis), which causes asymmetric pressure on the inter-vertebrae discs, which are squeezed outwards. Although the spine can be forcefully pushed back into its natural curve with an outspoken lumbar support, this will eventually cause discomfort and back pain, because the muscles of the lower back, the buttock muscles and lower muscles of the thigh are subjected to prolonged static load, which can result in acidosis in these muscles and pain symptoms. The lack of movement will eventually result in insufficient synovial fluid, which serves to lubricate the lower vertebrae and the intervertebral discs.

[0019] In some support structures, all of the individual surfaces, that make up the ergonomic platform must be secured into position in sequences, often with re-adjustments required, making the transition from one support position (e.g., a reclining position) to another (e.g., an upright seating position) cumbersome and time consuming.

[0020] The majority of products currently in the market do not meet or align with the current requirement and regulations in many countries of height adjustable tables, which demand a flexible workplace solution to offer a table height for either working while sitting down or standing up without a chair entirely.

[0021] Many products currently in the market also do not offer alternative applications of their use, for example, in industrial, medical, educational, or other fields that require an ergonomic seat support structure.

[0022] In view of the foregoing, there exists a need for an adjustable support structure, which addresses the above problems associated with the prior art.SUMMARY

[0023] Accordingly, provided are devices and assemblies for supporting the weight of a person, in particular a seated person, and specifically, an adjustable support structure or device, that is adjustable to alter the seating or reclining position of a subject resting on the structure particularly from an inclined forward position to a rearward reclined position. According to some non-limiting embodiments of the present disclosure, a support structure recognizes and supports the current state of anthropological and biomechanical facts. Furthermore, some non-limiting embodiments of the present disclosure allow and encourage a ‘seated’ person to shift the seating position upward and forward in a convenient, easily understandable, and self-explanatory way. The present disclosure generally provides for non-limiting embodiments of a support structure for supporting a person in a seated position, the support structure including a linear forward and upward or backward and downward moving apparatus to carry the weight of a person seated upon the support structure and a frame attached to the support structure to support the upper body portion, when leaning back (backrest), that supports angle variations of the seated person forward or backward through a reverse synchronized movement.

[0024] In some non-limiting embodiments, the support structure is incorporated into a chair, in particular a task or office chair, on which the subject may recline backward or ascent forward in a linear single movement, whereby the transverse pivotal axis of the motion is the knee joint as the reference fulcrum, meaning, while the upper thigh is evenly supported and in permanent contact with the seat pan surface in its entire length, the legs remain resting square on the floor. The compulsory dynamic movement allows the seated person to maintain, throughout the motion, a torso-to-thigh angle larger than 90 degrees. Incline and recline of the seat pan is achieved and controlled by two pairs of transverse connected pivotally hinged levers directly under the seat pan, which force the seat pan to move on a compulsory hinged parallelogram with uneven legs, also called parallelepiped, to describe an imaginative curved path with the fulcrum in the knee joint.

[0025] The fact, that throughout the entire motion from a backward reclined position to a high forward inclined position, a torso-to-thigh angle of 100 degrees or more can be maintained, the need to alter the angle ratio between seat and backrest is less relevant, since the primary function of the backrest is to support the upper body or torso when it tips backward over its balance point into a reclining position. As a desire or need may occur to further open the body angle closer to the zero posture (described further below), a backrest to seat angle adjustment is incorporated through a compulsory reverse synchronized movement adjacent with the seat pan.

[0026] To be able to elevate a person into a higher forward leaning position, the seat pan and the parallelepiped levers need to be supported by means of a force to lift a weight. There are several options available for imparting this force, such as a pneumatic cylinder or gas spring, a transverse torsion bar, or an electric actuator.

[0027] When installed with a lifting force in the form of a coil spring or a transverse torsion bar, the adjustable support structure may be a floating device, meaning, that with a corresponding adjustment of the spring to the weight of the seated person, the adjustable support structure may allow balancing the seated body, by changing the center of gravity in the upper body forward to move into a forward elevated posture, or by leaning backward into a relaxed backward reclining posture in a compulsory singular ‘floating’ movement without obstruction or effort.

[0028] Furthermore, while a forward inclining posture modulates the upper torso weight forward and away from the uplifting force and thus requires less force, the opposite movement backwards toward a reclining posture requires more uplifting force as the upper torso weight falls back and increases with further recline. Variations in the weight of different persons require a re-positioning of the characteristics of the uplifting force, which increases when reclining and lessens with the forward incline. This re-positioning can be achieved through a progressive coil spring or by changing the pre-tension of a transverse torsion bar. This re-positioning can also be achieved through a combined arrangement of a gas spring in tandem with a coil spring.

[0029] Finally, it may also be desirable, to lock the seat pan at certain angles for more comfort. A person may be unfamiliar with the floating movement and feel insecure, or a higher precision in movement control may be required for a task at hand. Thus, the said adjustable support structure comprises a means for securing (locking) in the form of a lockable gas spring.

[0030] In some non-limiting embodiments, the solution for the uplifting movement is an electric actuator, which replaces all the other solutions and allows for a precise and controlled modulation of the desired seat movement.

[0031] In some non-limiting embodiments of the present disclosure, the adjustable support structure may have only one releasable locking / detent means for the entire structure of the seat rest support and the arrest of the seat pan (D) movement in any inclination. A second means of lever or other device may be provided for the height adjustment and detention of the means of the uplifting force in portion (B) of the current embodiment.

[0032] The limitations of the terminal positions of the backward and forward movement of the seat pan may be controlled by limiting the movement of the weight lifting device through a travel limit extension of the locking device employed.

[0033] In some non-limiting embodiments, an ergonomic seating device to improve the posture of a seated person with a dual tilt mechanism, that allows and supports both a forward inclining and a rearward reclining seating posture, includes a foundation base assembly; a height adjustable seat support column assembly; an adaptive seat support link positioned on the base assembly and the seat support column to pivot horizontally about a vertical axis related to base assembly; an adaptive link supporting a pivotal seat assembly configured to support a seated persons upper leg; a dynamic moving seat support, that follows a modulated vertical motion along an arc path, with the fulcrum at the knee joint, allowing the seat assembly to maintain consistent contact with the full length of a person's thigh; a seat assembly with a concave recessed portion along a longitudinal midline of the seat support structure with a portion of the flexible seat support assembly configured to receive the rearward lower pelvic area wherein a recessed bowl portion has greater flexibility than the overall flexibility of the seat support structure; a bowl portion at the rear of the flexible seat support structure configured to arrest the buttock protrusion of the lower pelvis when inclining forward; a backrest support portion, which comprises a shell, foam and a backbone structure, which allows both horizontal and vertical adjustment; an armrest portion, which is mounted permanent to the backrest portion and follows the vertical and horizontal adjustment of the backrest movement; and a headrest portion, which is mounted to the back rest portion and is height adjustable in a slide, lockable by screw handle and vertical tilting by means of a frictional restricted hinge attached to the headrest shell.

[0034] In some non-limiting embodiments, a seat support assembly is configured to enable a user to dynamically adjust the posture from a higher forward inclined position to a lower rearward reclined position through a continuous linear movement, which is facilitated by transverse mounted pivotal levers, which are based on a parallelogram, as a simple quadrilateral with two unequal pairs of feeing sides, in its three-dimensional form, also called a parallelepiped, wherein said seat, when comprising said support structure, is operative to enable a person to move from a higher forward inclined position into a lower rearward reclined position in one single continuous movement and the movement is arrestable by means of a lockable gas spring controlled by a lever handle on the side of the structure.

[0035] In some non-limiting embodiments, a seat assembly includes an upper surface in the form of a flexible seat support structure, defining a modulated vertical motion on a path of an arc, that has its fulcrum in the knee joint and thus enabling a mounted seat pan to maintain permanent even contact with the entire length of the thigh of a person seated upon the upper surface.

[0036] In some non-limiting embodiments, the assembly of the transverse mounted pivotal levers facilitate, but do not limit, a lower rearward tilting angle of the seat pan of minus 5 degrees below a horizontal longitudinal alignment of the seat assembly.

[0037] In some non-limiting embodiments, the assembly of the transverse mounted pivotal levers facilitate, but do not limit, a forward inclining angle of at least plus 18 degrees over the horizontal longitudinal alignment of the seat assembly.

[0038] In some non-limiting embodiments, the adjustable seat support assembly includes a means of applying an uplifting force in the form of a longitudinal mounted lockable gas spring, which at the lower end is fixed onto the adjustable seat support assembly and at the upper end is fixed to the transverse mounted pivotal lever in a semi lying position within the seat support structure, which allows a seated person to move in response to the weight of the user bearing onto the seat assembly from a higher first forward position to a second lower rearward position, when the gas spring is unblocked, and secondly arrests the seat assembly between the first and second position when blocked by releasing the locking handle attached to the support assembly.

[0039] In some non-limiting embodiments, an adjustable seat support assembly includes a means to carry a backrest support frame or backbone, which is mounted horizontally and is vertically adjustable to a transverse mounted pivotal lever, which engages with the rear transverse mounted pivotal lever of the parallelepiped, with lateral pivotal hinge points attached to the support structure by means of a herringbone gear incorporated on the surface of both the backrest support lever and the rear pivotal lever of the parallelepiped, such that a synchronized compulsory reverse movement of the backrest support occurs with an over-proportional change of angle relative to the seat pan in such a way that the lateral angle between the seat and back increases to 120 degrees when tilting forward and decreases to 110 degrees when reclining backward.

[0040] In some non-limiting embodiments, a backrest support frame or backbone moves on a translateral hinge lever and simulates a modulated movement with a fulcrum in the hip joint to prevent the up-lifting of a shirt or clothing of a seated person; which furthermore is adjustable both laterally and vertically to allow ergonomic alignment according to the proportions of a seated person, by means of a screw type locking handle, the depth adjustment facilitated through a slot in the transverse mounted pivotal lever of the support assembly and a vertical slide and slot at the bottom and the rear of the backbone structure.

[0041] In some non-limiting embodiments, an adjustable support assembly which facilitates the mounting of a modulated seat assembly structure includes an outer shell made of recycled ABS or a thermoset compound with natural fibers; a composite flexible injection molded foam insert made of PU or natural latex, which allows a soft cushion to be inserted in the rear part of the seating surface, which forms a bowl to arrest the buttocks of a seated person in such a way, that when tilting forward on the seat, sliding down is prevented through the contour that is formed in the seat by the bearing of the seated person; and a foam cover made of a fabric or a perforated natural latex membrane, which has anti-skid properties to further prevent sliding on the surface and retain a seated person on an optimum contour.

[0042] In some non-limiting embodiments, an adjustable support which facilitates the mounting of a modulated backrest support structure includes an outer shell made of recycled ABS or a thermoset compound shell with natural fibers; a composite flexible molded foam insert made of PU or natural latex; and a foam cover made of a fabric or a perforated natural latex membrane.

[0043] In some non-limiting embodiments, a backrest support frame allows a height adjustable headrest to be mounted on top of the backrest support structure by means of a sliding bracket, which slides inside the backbone and is locked by a screw type locking handle limited by a slot at the back and the headrest adjusting by means of a hinge to a desired angle by the user.

[0044] Some non-limiting embodiments as described herein are designed to accommodate the most common seating situations in the current office environment. Some non-limiting embodiments are also suitable for and encourage the use of height adjustable tables in the office working environment aimed to solve back pain problems, by switching effortlessly between a low sitting position and an elevated high up and articulate forward leaning working position with infinite positions in between.

[0045] In addition, the construction and movement of non-limiting embodiments of the present disclosure also offer to be applicable in many other situations, where a person needs an elevated seating support for various tasks, which traditionally can only be achieved with different specific chairs.

[0046] To complement the description which is being made and with the aim of aiding to better understand the features of the disclosure according to a preferred exemplary embodiment thereof, a set of drawings is attached as an integral part of said description, in which the following is shown with an illustrative and non-limiting character.BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Additional advantages and details are explained in greater detail below with reference to the exemplary embodiments that are illustrated in the accompanying drawings, in which:

[0048] FIG. 1 depicts a schematic side view of a non-limiting embodiment of an office chair in accordance with the present disclosure;

[0049] FIG. 2 depicts an isometric view of a non-limiting embodiment of the office chair of FIG. 1 in accordance with the present disclosure:

[0050] FIG. 3 depicts a schematic side view of the anatomic premise on which non-limiting embodiments of the present disclosure are based on and reference;

[0051] FIG. 4 depicts a schematic side view of a non-limiting embodiment of a common situation of seat structures offered to the market at present, showing the angles of a generally backward tilted position, and a second acute forward tilted position achieved by non-limiting embodiments in accordance with the present disclosure;

[0052] FIG. 5 depicts an isometric exploded view of non-limiting embodiments of the components of an adjustable support structure portion in accordance with the present disclosure;

[0053] FIG. 6 depicts an isometric exploded view of non-limiting embodiments of a hinge arrangement of the support structure portion between a transverse pivotal backrest support lever and a transverse pivotal rear lever of the parallelepiped, that controls the reverse synchronized movement of the backrest in relation to the seat pan by means of a dual engaging herringbone gear in accordance with the present disclosure;

[0054] FIG. 7 depicts a fundamental schematic function of a non-limiting embodiment of an adaptive structure of the parallelepiped in accordance with the present disclosure;

[0055] FIG. 8 depicts a side view of a non-limiting embodiment of the support structure assembly of FIG. 7 in an assembled position, and its members referring to the assumptions of FIG. 4 in the known horizontal position in accordance with the present disclosure;

[0056] FIG. 9 depicts a side view of a non-limiting embodiment of the support structure assembly and its members and proportions as shown in FIG. 10, raised to the acute forward tilted position, and showing the alignment with the fulcrum reference point of the knee joint in accordance with the present disclosure;

[0057] FIG. 10 depicts a side view of a non-limiting embodiment of the support structure assembly and its members and proportions as shown in FIG. 10, lowered to a reclined rearward position, and with a continuous fulcrum reference point in the knee joint in accordance with the present disclosure;

[0058] FIG. 11 depicts an exploded isometric view of a non-limiting embodiment the means of adjustment of a backrest support lever or backbone, by which a height of a backrest and a seat depth are adjustable in relation to a seat pan in accordance with the present disclosure;

[0059] FIG. 12 depicts a side view of a non-limiting embodiment of a flexible foam insert arrangement of a seat to form an articulated contour through different densities in the foam in accordance with the present disclosure;

[0060] FIG. 13 depicts an isometric exploded view of a non-limiting embodiment of an arrangement of separating two different densities in a flexible seat foam and its insertion and fixing in accordance with the present disclosure;

[0061] FIG. 14 depicts a side view of a human body seated upon a non-limiting embodiment of a contoured seat foam insert of a non-limiting embodiment of a support structure assembly implemented in a chair in an elevated forward tilting position in accordance with the present disclosure;

[0062] FIG. 15 depicts a side view of a non-limiting embodiment of a support structure assembly implemented in a chair in a lower reclined position in accordance with the present disclosure;

[0063] FIG. 16 depicts a side view of a non-limiting embodiment of a support structure assembly implemented in a chairs in a traditional ninety degree angle seat position in accordance with the present disclosure; and

[0064] FIG. 17 depicts a side view of a non-limiting embodiment of a support structure assembly implemented in a chair in an acute forward tilted position in accordance with the present disclosure.

[0065] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the disclosure, and such embodiment are not to be construed as limiting the scope of the disclosure in any manner.DETAILED DESCRIPTION

[0066] It is to be understood that the specific devices and processes illustrated in the attached drawings and described in the following specification are exemplary and non-limiting embodiments of the inventive concepts defined in the appended claims. Hence, specific physical characteristics relating to the non-limiting embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

[0067] FIG. 1 generally depicts an office chair and schematically represents a non-limiting embodiment of the disclosure. As will be evident from viewing FIGS. 1 and 2, the seating assembly may generally include eight elements:

[0068] a five-prong base assembly (denoted A),

[0069] a support column assembly (denoted B),

[0070] a support structure in the form of a mechanism (denoted C),

[0071] a seat pan (denoted D),

[0072] a support structure in the form of an armrest (denoted E),

[0073] a support structure in the form of a backbone (denoted F),

[0074] a backrest support structure (denoted G),

[0075] a support structure in the form of a headrest (denoted H),

[0076] The base A may be structured as a classic 5-prong rolling leg frame which acts as a support mount for structure B, which may include a standpipe with a nylon bush insert, which may carry a telescopic gas cylinder, which may be configured to be adjusted in height in order to adapt to the specific seat height of each user for such a seat support structure.

[0077] Mounted upon assembled structures A & B may be the mechanism C and seat pan D, which may at least partially form the adjustable seat support assembly according to some non-limiting embodiments of the present disclosure and which includes a plurality of portions, which will be described in detail below.

[0078] FIG. 3 depicts the biomechanical background and explanation for the function of the present disclosure and describe part of the human skeleton, in particular the arrangement of the bone structure and movement around the hip joint. FIG. 3 shows the relative angles between the pelvis and thigh bone when sitting on a horizontal seating surface and when tilted up and forward by 18 degrees or more over the horizontal. It is by now a scientific established fact, that the maximum angle of lateral movement between hip bone and pelvis is 60 degrees, while the remaining 30 degrees take place in the lumbar part of the spine directly above the pelvis, the result of which is a conversion of the natural spine curve (lordosis) into the opposite curve (kyphosis).

[0079] FIG. 4 depicts firstly the seating configuration and the corresponding torso-to-thigh angles of a traditional seating support structure in a traditional horizontal position and illustrates the effect of the limitation of seat support structures most commonly present in the market, whereas 4.a represents the pivotal location of the hip joint, the knee joint in 4.b and the pivotal point of the foot in joint 4.c, which remains stationary through the whole movement. Secondly, FIG. 4 depicts a position that may be achieved by non-limiting embodiments of the present disclosure in which the seating support structure allows a torso-to-thigh angle of 115 degrees or more to be maintained throughout the entire elevation movement from the utmost lower back recline to the upper most forward incline. This position may allow the curve of the spine in the lumbar region to be maintained as close as possible to its natural curve, which requires a forward tilting angle of the seat pan in alignment with the thigh corresponding to the knee joint. FIG. 4 also demonstrates the angles which non-limiting embodiments of assemblies of the present disclosure achieve through the multi-pivotal levered elevation of the seat pan, whereas during the entire movement in the forward inclined position a lower-to-upper thigh angle of 115 to 120 degrees and in the lower backward reclined position a torso-to-thigh angle of at least 110 to 115 degrees may be sustainable.

[0080] FIG. 5 depicts an exploded isometric view of non-limiting embodiments of the components of the apparatus assembly of portion C in FIG. 1. FIG. 5 depicts a transverse mounted pivotal lever 7 which may engage with the rear transverse mounted pivotal lever 4 of the parallelepiped by means of a herringbone gear incorporated on the surface of both the backrest support lever 7 and the rear pivotal lever of the parallelepiped 4, which may force a synchronized compulsory reverse movement of the backrest support with an over-proportional change of angle relative to the seat pan (see, e.g., FIG. 8).

[0081] FIG. 5 further depicts a transverse mounted pivotal front lever 5 of the parallelepiped, which may be fixed at the front to the base housing 2 and at the upper rear end to the top support plate 6, and may form in combination with the rear pivotal lever 4 the parallelepiped.

[0082] FIG. 5 also depicts the position of the release lever 10.a on the right side and the release bowden cable 8.3 for the release adjustment of the gas spring for the height adjustment in portion B in FIG. 1 and the release bowden cable 3.4 connected to the release lever 10.b, which may activate the release or locking of the support gas spring 3. FIG. 5 further depicts the arrangement of the means for imparting an uplifting force 3 in the form of a coil spring supported gas lift between the base 2 and the attachment to the rear leaver support 4.

[0083] FIG. 6 depicts an illustration of the interconnecting herring bone gear between the lateral pivotal backrest support lever 7 and the lateral pivotal rear lever of the parallelepiped 4.

[0084] FIG. 7 depicts the articulation of the movement of the seat pan from lower reclining to higher forward tilting by employing a parallelepiped to simulate a rotation of the seat pan around the exemplary fulcrum of the knee joint.

[0085] FIG. 8 depicts a non-limiting embodiment of the present disclosure in which the various portions of the support structure C may be connected via hinge or pivot means to define the support structure C in a horizontal position, whereas the uplifting force 3 is at its lower hinge point pivotally hinged to the bearing structure 2 in point 3.1 and at its upper end to the transverse pivotal rear lever 4 in pivot point 3.2. The upper forward pivotal hinged lever 5 is at its lower end hinged pivotal to the front of bearing base 2 in point 5.1 and at its upper end to the seat pan support plate 6 in point 5.2. The lower backward pivotal hinged lever 4 is at its lower point pivotally hinged to the bearing base structure 2 in point 4.1 and at its upper pivotal point to the seat pan support plate 6 in point 4.2.

[0086] FIG. 9 shows a non-limiting embodiment of the support structure C moved into a desired second forward inclined position and illustrates how the support structure C enables the subject supported by the structure to be moved from a relative lower backward reclining position to an acute elevated forward seated position (and vice versa), or to any position along a continuum between those two extremities. As is illustrated in this depiction, the range of movement between the first and any desired second position may be controlled and limited solely by the extent of movement permissible of portion 3.

[0087] FIG. 10 depicts a non-limiting embodiment of the apparatus assembly of portion C shown in FIG. 8 in its rearward reclined status.

[0088] FIG. 11 shows the connecting bracket between the adaptive support structure C and the backrest support structure F with oval slots which may allow ergonomic alignment according to the proportions of a seated person both laterally and vertically, by means of a screw type locking handle.

[0089] FIGS. 12 and 13 depict the arrangement and fixing of two separate portions of flexible foam, whereby the overall seat foam density is higher than the soft foam pad, which may be inserted at the rear of the seat to allow the formation of a cavity or a bowl, which retains a seated persons buttocks in said bowl, based on the anatomy of the human body as shown for example in FIG. 14.

[0090] FIG. 14 depicts a side view of a non-limiting embodiment of the assembly according to the present disclosure with a human body placed on the inclined forward tilting seat pan D and the contour formed under the upper thigh with the protruding buttock at the rear.

[0091] FIG. 15 depicts a side view of a non-limiting embodiment of the assembly according to the present disclosure as in FIG. 14, with a person sitting on it in reclining posture.

[0092] FIG. 16 depicts a side view of a non-limiting embodiment of the assembly according to the present disclosure as in FIG. 14, with a person sitting on the horizontal seat.

[0093] FIG. 17 depicts a side view of a non-limiting embodiment of the assembly according to the present disclosure as in FIG. 14 with the desired forward seat inclination.

[0094] Accordingly, the present disclosure is directed to non-limiting embodiments of a seating support structure for implementation in an office chair, and to non-limiting embodiments of office chairs including such a seating support structure, which allow a user to sit upright on a forward-tilting elevated seat support, which tilts the pelvis forward, opens the body angle between the thigh and the upper body and allows the user to maintain a natural curved spine while sitting. Because of the elevated forward tilting seat, it provides an easy-sitting and easy-rising motion, while the feet remain squarely placed on the floor. This encourages more frequent motion and supports a more dynamic seating in particular, when combined with a height adjustable table, and aims to solve one of the most prominent medical conditions of lower back pain.

[0095] It is to be understood, that while the embodiments of the present disclosure have been described with respect to implementation in an office chair, the devices and assemblies are applicable for, but not limited to, implementation with regard to chairs, seat, support devices and / or to any other conceivable device in any conceivable position, and it is considered that there are various other configurations and uses for supporting a user with the devices and assemblies of the present disclosure.

[0096] While several examples of devices and assemblies for properly and adjustably supporting a user are shown in the accompanying figures and described in detail hereinabove, other aspects will be apparent to, and readily made by, those skilled in the art without departing from the scope and spirit of the disclosure. Accordingly, the foregoing description is intended to be illustrative rather than restrictive. The disclosure described hereinabove is defined by the appended claims and all changes to the disclosure that fall within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

1-9. (canceled)10. A chair, comprising:an adjustable seat support structure for modifying the posture of a seated person with a dual tilt mechanism, which allows and supports both a forward inclining and a rearward reclining seating posture, the adjustable seat support structure comprising:a foundation base assembly;a height adjustable seat support column assembly;an adaptive seat support link, positioned on the foundation base assembly and the height adjustable seat support column assembly to move vertically up and down to accommodate various person heights and pivot 360 degrees horizontally around a vertical axis related to the foundation base assembly;an adaptive and lockable dual tilt mechanism, supporting a pivotal seat assembly configured to support an upper leg of a seated person;a dynamic moving seat support, that facilitates a modulated pivotal motion through a transverse parallelepiped lever assembly, which is at a bottom pivotally hinged to a base housing of the dynamic moving seat support and at a top is pivotally hinged to a top plate, which enables and simulates an arc path with a fulcrum in a knee joint, allowing a seat surface to maintain permanent contact with a full length of a thigh of a seated person;a seat assembly mounted to the top plate of the dynamic moving seat support and comprises a concave recessed portion at a rear along a longitudinal midline of a flexible seat support structure with a portion of the flexible seat support structure configured to receive a rearward lower pelvic area, and a flat forward portion to support a thigh;wherein the seat assembly includes a bowl portion at a rear of the flexible seat support structure configured to arrest a buttock protrusion of a lower pelvis when inclining forward and wherein the bowl portion has a greater flexibility than an overall flexibility of the flexible seat support structure;wherein the seat assembly includes a fabric cover, which has added frictional rubber dots to a surface, to create slide resistance when the seat is tilting forward;a backrest support portion which is adjustable and lockable horizontal and vertical by sliding on a 90 degree j-bar fixed to the dynamic moving seat support and comprises a shell, foam padding, and a backbone support structure;an armrest support portion, which is mounted permanent to a backrest and follows the vertical and horizontal adjustment of the backrest movement, allowing the ergonomic alignment of the elbows with the corresponding position of the lumbar support of the backrest; anda headrest, which is mounted to the back rest support portion by a j-bar and is vertical adjustable by means of frictional resistance inside a slide slot of the backrest support portion and horizontal adjustable by a slide slot inside a headrest adaptor, arrestable by means of a knob or screw.

11. The chair of claim 10, wherein the adjustable seat support structure comprises a lever handle to lock or unlock the height adjustable seat support column assembly, and an uplifting force imparting means selected from at least one of: a longitudinal mounted pneumatic lockable gas spring; a transverse torsion bar, or an electric actuator.

12. The chair of claim 10, wherein the adjustable seat support structure provides for a modulated vertical and forward motion on a simulated path of an arc, that has its fulcrum in the knee joint and thus enabling a mounted seat pan to maintain permanent even contact with the entire length of the thigh of a seated person.

13. The chair of claim 10, wherein the transverse parallelepiped lever assembly facilitates, but does not limit, a longitudinal rearward tilting angle of the seat pan of at least minus 5 degrees below a horizontal alignment of the seat pan.

14. The chair of claim 12, wherein the adjustable seat support structure facilitates, but does not limit, an up and forward tilting angle of the seat pan of at least plus 18 degrees over the horizontal alignment of the seat pan.

15. The chair of claim 11, wherein the longitudinal mounted pneumatic lockable gas spring, has a lower end which is fixed onto the adjustable seat support assembly base and an upper end which is fixed to the rear transverse mounted pivotal lever in a semi lying position within the seat support structure, enabling a seated person to move in response to the weight of the person bearing onto the seat assembly from a higher first forward position to a second lower rearward position, when the gas spring is unblocked, and secondly enabling an arrest of the seat assembly between the first and second position when blocked upon releasing the locking lever handle attached to the dynamic moving seat support.

16. The chair of claim 10, wherein the adjustable seat support structure is provided with an adaptive means to accommodate a fixed angle j-bar bracket to carry the backrest assembly, being adjustable horizontally by means of a slide in the support structure and lockable by a wheel knob.

17. The chair of claim 10, wherein the adjustable seat support structure facilitates the mounting of a flat or modulated seat pan assembly to be fixed on top of the dynamic moving seat support.

18. The chair of claim 10, further comprising:a backrest support assembly which is height adjustable to allow for lumbar alignment and adjustable in depth to accommodate various person sizes.

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