Seat Configuration

This application is a continuation of U.S. Non-Provisional application Ser. No. 18/460,225, now U.S. Pat. No. 12,342,944, filed Sep. 1, 2023, entitled “SEAT CONFIGURATION;” which is a continuation of U.S. Non-Provisional application Ser. No. 17/848,688, now U.S. Pat. No. 11,744,375, filed Jun. 24, 2022, entitled “SEAT CONFIGURATION;” which claims the benefit of U.S. Provisional Patent Application No. 63/221,669, filed Jul. 14, 2021, entitled “SEAT AND BACK FOR A CHAIR”, the entire contents of each of which are hereby incorporated by reference herein in their entirety.

Proper posture is not only important for the spine, but also the pelvic region and shoulders. Sitting without proper posture repeatedly and for long periods of time can eventually lead to chronic back pain, shoulder and neck pain, or even permanent or semi-permanent misalignment of the spine, which may require medical intervention to correct. Additionally, sitting in a hunched over position can affect a person's breathing.

A majority of people work in an office job or another job that requires sitting upright in a chair or seat for extended periods of time, often for more than 8 hours in a single day. Typical seating used by people of all sizes does not adjust to fit each individual's unique sitting needs anthropometrically, biomechanically, or at the general comfort level. General comfort is often tough to quantify but it is common medical knowledge that pain from tissue, joint, muscle, etc. is simply derived from a person's nociceptors. The nociceptor that determines pain in the seated space is known as the mechanoreceptors. The four main types of mechanoreceptors are the Merkel disks for the pressure, the Ruffini corpuscles for the stretch and shear stresses, the Pacinian corpuscles for vibration, and the Meissner's corpuscles primarily providing information about tactile and sensitive changes. The Merkel disks and the Ruffini corpuscles mechanoreceptors are slowly adapting cutaneous mechanoreceptors. For comfort, slowly adapting mechanoreceptors are more critical than fast adapting mechanoreceptors. Therefore, parameters in the interaction zone that may be relevant to comfort are pressure elongation and shear stress. These findings were not published until 2005 and were not examined as relevant to seating comfort until 2020. Thus, previous chair designs trying to apply posterior lifting features to the pelvic and thoracic regions did not take into account that the forces from the back supports were creating an equal and opposite shear force across the seat of the occupant and impacting Ruffini corpuscles.

For example, in U.S. Pat. Nos. 7,040,703, 7,396,082, and 4,981,325, each device tries to apply a force to the sacral and thoracic regions, but do not attempt to counteract that force. This will lead to the pelvis of the occupant sliding forward over time, resulting in an unstable posture, and/or will lead to discomfort caused by a reaction of the Ruffini corpuscles.

Nociceptors are located in the skin, muscles, skeletal structures, and viscera and are responsible for sending pain signals to the brain for a person to process and then take appropriate action. If a chair doesn't fit a user properly, the user may sit awkwardly causing tissue or joint pain. Additionally, the tissue or joint pain often causes the user to move or fidget in the chair. If a chair can adjust to truly fit the size and shape of the user, exert low peak pressure and low shear on the tissue surfaces, and hold the user's pelvis, spine, and head in a neutral posture alignment, the user may experience less pain while sitting, thus achieving greater comfort over time. This is not an easy task, and a solution is desired to achieve the above-mentioned steps for increased comfort over time and improved sitting capabilities or tolerances.

In the state of the art of biomechanical laws for sitting and standing, neutralizing one's pelvis in space will result in establishing a natural lumbar curve and alignment of the mid/upper thoracic region. Applying a force or device directly to L1-L4 does not provide biomechanical advantage in lifting the upper thoracic region and/or have the preferred ability to rotate the pelvis into a neutral state. It can be hard for the human body to tolerate the pressure on the L1-L4 that would be required to lift one's central mass using a lumbar support. Supporting/rotating the pelvis gives a user the biomechanical advantage to rotate the pelvis about its natural pivot point, which is the acetabulum (e.g., socket for femoral head). What is known as natural lumbar curvature can more easily be achieved by simply controlling the angle of one's pelvis. When a person is standing or sitting with correct posture/alignment, the pelvis should be within three degrees of neutrality in a posterior/anterior rotation. The human pelvis when standing and measured between the PSIS and ASIS has a balanced/neutral axis of 7 to 10 degrees. Meaning that the pelvis can travel plus or minus 1.5 degrees (i.e., 1.5 degrees in an anterior direction or 1.5 degrees in a posterior direction) before being defined as coming out of neutrality. When in a neutral (or optimal position), the L5, which is firmly held in place to the pelvis with the iliolumbar ligaments, is stacked upright which also allows the L4, L3, L2, and L1 to have an optimal lumbar curve. As an example, when the pelvis begins to rock forward or backwards, the movement of the pelvis holding L5 causes L4, L3, L2, and L1 to sway out of place. Thus, when the pelvis has a posterior rotation, for example in a slouching posture, the person loses their lumbar curve due to the backwards rotation of the L5 within the pelvis, thereby toppling the other lumbar segments. Angling the pelvis too far in the anterior direction results in excessive lordotic posture and angling the pelvis too far in the posterior direction results in slumped or c-shaped sitting. In lordotic posture, there is typically no disc bulging. However, in slumped posture, the disc pressure increases, resulting in bulging of the discs. This is why keeping a neutral pelvis is seen medically as an optimal outcome for long term healthy sitting. This neutrality is what holds L5 at a certain angle in space. L4-L1 follow this arcuate path establishing natural lumbar curve, giving proper disc spacing. When you rotate the pelvis anteriorly or posteriorly, the angles of L5 and L4 follow the rotation of the pelvis because L5 and L4 have so many surrounding ligaments tying them to the pelvis. Thus, when the angles of L5 and L4 change, the natural hinging between L3, L2, and L1 starts reducing or inducing curvature. The further you rotate the pelvis backwards/posteriorly, the more you lose your natural lumbar curvature. It should be made clear that the pelvis's rotational position in space is what controls flexion or extension of the lumbar spine region, which in turn affects intradiscal pressure. Passive extension of the spine on the posterior side causes intradiscal pressure, this leads the nucleus pulposus to migrate anteriorly and thus relieve pressure on pain sensitive structures of the spine including the posterior longitudinal ligament and annulus fibrosis. Thus, controlling one's posture by articulating the pelvis rotation in space is the preferred medical approach to establishing and supporting a natural lumbar and thoracic curve and proper intradiscal pressure.

It should be made clear that if the pelvis is not held in a neutral state, it is biomechanically impossible to restore natural spinal column alignment throughout the entire spine. This is why holding the pelvis in a neutral state during sitting or standing is the only way to stand or sit without adding disc pressures, stress, muscle imbalance and/or fatigue, and joint pain to the entire trunk of the human body.

A seating configuration is described. The seating configuration includes a seat. The seat includes a feature to retain a user in a specific position on the seat. The seating configuration includes a first back support. The first back support is positioned adjacent a posterior pelvic area of the user. The seating configuration includes a second back support. The second back support is positioned adjacent to the thoracic area of the user. The seat, the first back support, and the second back support together can be configured to create a natural alignment of a spinal column of the user.

It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary to the understanding of the invention or render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.

One or more specific embodiments will be described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

is a representation of a user's typical seated posture in an existing chairthat does not have features (e.g., support surfaces) that are capable of properly supporting a person and promote a proper seated posture of the person.depicts a representation of the forces acting on a user while sitting. The existing chairis depicted as a standard chair, but may instead be another type of seating, such as but not limited to an office chair, airplane seating, vehicle seating, industrial equipment seating, stadium seating, theater seating, residential seating, etc. As shown in, the depicted standard chair does not promote proper alignment of the pelvis (e.g., pelvic-sacral-lumber region)and spineof the user. Proper alignment of the pelvic-sacral-lumbar regionand spinal columncan be seen when the pelvisis aligned within three degrees of a neutral position (i.e., plus or minus 1.5 degrees in each direction). The proper alignment of the pelvic-sacral-lumbarregion and the spinecreates proper disc spacing. Improper disc spacing can cause an endless amount of negative health effects. To prevent the negative health effects of improper alignment and disc spacing while sitting, it is important that a person is able to have the pelvisand entire spinal column(i.e., from lumbar to cervical segments) aligned within three degrees of a neutral position when sitting (e.g., in a chair, in a vehicle, on other furniture types, etc.). When the pelvisis in a neutral state while sitting, the ITs are exerting the highest peak pressures (which cause the Merkel disc mechanoreceptors to fire pain signals) through tissue between the bone and a seating surfaceof the chair. In order to allow the user to sit with proper spine alignment, the peak pressures on a user's ITs must be below a tolerable threshold that do not cause the Merkel pain receptor to fire. Studies have shown that the preferred peak pressure threshold is lower than 124 mmHg. Other studies have indicated that when shear stress is present, thus affecting the Ruffini corpuscles mechanoreceptors, the threshold is reduced to 65 mmHg. A comfortable pressure with no shear was recorded at 87 mmHg and when shear was introduced, the comfortable pressure tolerance lowered to 64 mmHg. Thus, reducing both peak pressure and shear stress in the seated plane is critical for improving sitting comfort over time.depicts a representation of the forces acting on a user while sitting. The forces include gravity (G), pressure (e.g., the peak pressures on the IT's) (P), and shear stress(S). Additionally, the pelvic tilt affects the posture of the user and should be accounted for. A slumped thoracic region also causes an additional downward angled force that should be counteracted.

Additionally, the seat typically has minimal or no support characteristics to hold the inferior surface of one's pelvislaterally and typically also lacks features to prevent shearing on the anterior side of the Ischial Tuberosities (IT's), which reduces sliding of the pelvic area forward and backward. This lack of support results in pelvic collapse and typically leads to the user being in slumped or slouched forward seating position. In addition, a user will unknowingly lean side to side in an attempt to avoid discomfort within their sit bones and/or their spinal column. Leaning and/or fidgeting is a side effect of feedback from the mechanoreceptors (i.e., the Merkel disc and the Ruffini corpuscles) that indicates discomfort or soreness while sitting. If a user's sit bones (IT's) are sore, they may also tend to perch on the front edge of the chair to help alleviate this soreness, which ultimately was caused by high peak pressures on their sit bones. Perching on the edge of the chair may provide temporary relief by lowering the distal end of the user's femurs, thus lifting their pelvis. This perching behavior to avoid sit bone pain pulls the user away from any back support feature that could help them sit upright with ease. With no back support, the body will fatigue quickly due to the large amount of muscle groups that need to be activated in order to hold the user in a pelvic/spine neutral position. This is not optimal or comfortable sitting behavior for 6 to 8 hours a day.

As shown in, in a typical seating position, the pelvisof the user is tipped back instead of in a natural, neutral alignment. The back support of the chair depicted inis substantially flat and/or not curved in the proper alignment to prevent lower back pain. Alternatively, in a chair with a lumbar support, the lumbar support is expected to lift both the upper thoracic regionas well as pelvic-sacral-lumbar regionby applying pressure to the smallest cross-section of the skeletal regions (i.e., the lumbar region, specifically L1-L4) associated with upper body alignment. Biomechanically speaking, it is not optimal to apply so much pressure to such a weak/small section of the spine. The pressure on the lumbar regionof the spine caused by traditional lumbar supports often results in a feeling of acute pressure/lift in the user, triggering a mechanoreceptor response and ultimately causing the user to fidget due to the discomfort. While some chairstry to force the lumbar regioninto the proper curve, the users of these chairsoften still slump forward for comfort or due to core muscle fatigue, rendering any lumbar support ineffective. A study of lumbar supports found that in order to maintain lumbar lordosis in sitting, a lumbar pad would need to be 9 cm thick, however, participants tended to complain that such a thick lumbar pad pushed their body too far forward, thus resulting in a center of pressure (CoP) that was more anteriorly located on the seat pan. The center of pressure being more anteriorly located resulted in an increase of shear stress through the seated plane, thus reducing comfort and causing the Ruffini receptors to fire.

Moving to the thoracic regionof the spine, in a normal user's seated posture, as depicted in, the thoracic-cervical regionis rounded forward. Without proper pelvis alignment, a user must engage the abdominal, back, neck, and shoulder muscles to maintain proper posture in the thoracic-cervical region. Most users are unable to do this for the extended lengths of time often required while in a typical task or resting position within a chair. The majority of people sit for 8+ hours a day for their jobs, many of those people sitting at a desk. The resulting rounding of the thoracic regioncan lead to back pain or other health problems from repeated and extended positioning in this way.

Furthermore, most users keep their shouldersin a forward position because the thoracic-cervical regionis not properly supported around the T10-T12 segments of the spineby the back support of the example chair in. This lack of support causes the upper thoracic regionto have an anterior lean, thus allowing the shouldersto rotate forward and the cervical region and head to fall forward. The slumped forward thoracic region, shoulders, and neckmay lead to pain and soreness in the muscle groups from the sternum through the shoulders and neck.

In addition to the muscle strain and fatigue in the back, shouldersand neck, a typical chairalso causes excess pressure on the ischial tuberosity(may colloquially be referred to as sit bones). The seatof the chairmay also cause shear pain directly beneath and/or on the anterior side of the ischial tuberositieswithin the tissue, muscle, and fat that is compressed between the seat surface and ischial tuberosities. This shear pain (i.e., response from the Ruffini corpuscles mechanoreceptors) is induced when a user is sliding in a seated plane; not only is this uncomfortable, it is also dangerous and reduces blood flow, which destroys one's cells more quickly than pressure alone (i.e., a response from the Merkel disc mechanoreceptors). Shear within a seating system will also trigger a nociceptive pain signal more abruptly than pain or discomfort caused by pressure. Pressure pain and/or shear pain will cause the user to frequently re-adjust to find a more comfortable sitting position regardless of how optimal a back support may be.

Sitting too long with the spinein improper seated posture leads to chronic pain and potential back injury (i.e., repetitive stress injury). Unfortunately, sitting for long periods of time is unavoidable for many people, for example, people working in offices, farmers, people operating heavy machinery or public transportation, etc. Thus, it is important that the chair back(s), in combination with the seat in which the user is expected to sit for extended periods of time, provides proper support and reduces peak pressures within all of the support surfaces to allow the user to rest and/or focus on a task. Such a combination of a seat and chair back(s) also encourages proper posture for the entire spinewhile again not sending nociceptive pain signals to the brain.

depict an example seat configurationincluding a seat, a first or lower back support(e.g., a pelvic-sacral-lumbar back support) and a second or upper back support(e.g., a thoracic-cervical back support), described in more detail herein. The example seat configurationis an ergonomic design that encourages a comfortable and adaptable ergonomic posture for each unique user. The example seatand back supports,promote proper seated posture for the user. Not only do the back supports,promote proper posture, but the seating configurationalso provides prolonged comfort and support to the user to help the user comfortably remain in the proper seating position for an extended period of time. When the back supports,are in the proper positions for a specific user, the seatand back supports,ideally hold the user's pelvis within three degrees of a neutral position, thus supporting each unique user's body shape in proper alignment from the lumbar to the cervical regions with very limited engagement of user's core and upper back muscles. While the example first and second back supports,are shown as separate back supports, the first and second back supports,may be connected using any flexible means of flexible membrane, which may include a cover over the supports,or may just stretch between the supports,, that enables adjustment of at least one back support relative to the other back support. The flexible membranemay include fabric, foam, mesh, a spring or springs, or any other flexible connection. Similarly, while the back supports,are depicted as being separate from the cushion, the lower back support may be connected to the cushion using any of the flexible membranewhich allow movement of the back support relative to the cushion. Additionally or alternatively, a flexible fabric or material (including a foam) may cover one or more of the cushions, first back support, and second back support. That is, one or more of the cushions, first back support, or second back supportmay be covered together and/or separately using upholstery, which may include a foam layer. Examples of the flexible membraneare depicted in.depicts the seat with a flexible membranein the form of a cover positioned over the upper and lower back supports,.depicts the seat with a flexible membranein the form of a cover positioned over the seat, upper back supportand lower back support.

The example seat configurationincludes a seatthat includes a contoured pelvic welland inclined femoral surface, both of which are retaining features that prevent forward migration of the user's pelvis, allowing an input of the pelvic-sacral-lumbar supportto rotate the pelvis upward and hold the pelvis in the neutral state. The pelvic welland the inclined femoral surfaceprovide a force in the posterior and downward direction (from the anterior side of the pelvis) to counteract the force of the first and thoracic-cervical supports in the anterior direction (from the posterior side of the pelvis). Thus, the pelvic welland inclined femoral surfacemaintain the position of the user toward the rear of the seatto keep the user's pelvis in contact with the pelvic-sacral-lumbar supportand keep the user's thoracic region in contact with the thoracic-cervical support. In fact, a study has shown that a contoured seat surface has a greater effect on uniformity of pressure distribution and that a lower peak pressure implied an improvement of the user's comfort on the seat. Thus, the example seatincluding the pelvic welland inclined femoral surfaceprovides greater comfort by reducing the seating pressures in addition to maintaining the position of the user so that the user can feel the full effect of the pelvic-sacral-lumbar and thoracic-cervical supports,.

The illustrated construction ofdepicts the seatand back supports,in use with an example office chair(e.g., a task chair, an executive chair, etc.). The seatin the example construction depicted inis attached to a seat panand baseof an example office furniture. The back supports,are attached to the baseof the example office furniture using one or more frame members (e.g., first support arms, second support arms) coupled to respective back surfaces,(shown in) of each back support,. The example office chair may also include arm rests.

Alternatively, a seatand back supports,as described herein may be used in other environments. For example, the configurationof the seatand back supports,may be used in a vehicle, an airplane, an entertainment venue, in industrial and/or farming equipment, or generally in any type of chair or seat in which the user is expected to sit in a plurality of positions for long periods of time, ideally with positive comfort over time. The design of the seatand the pelvic-sacral-lumbar and/or thoracic-cervical supports,can be adapted for use in a plurality of other seating situations, for example, by attaching the seatto a different base and the pelvic-sacral-lumbar and/or thoracic-cervical supports,to a different type of back frame and/or seat. The configurationof the seatand back supports,is such that the proper curvature of the spine is established and is comfortable for seated tasks, such as using a computer, operating heavy machinery, or driving, but may also be beneficial for sitting in a comfortable upright position as a passenger (e.g., of public transportation, a plane, etc.) or watching a movie, performance, or game in theater/stadium style seating. The seatmay also be used with solutions for mobility challenged users (e.g., wheelchairs (both manual and power), feeder seats, strollers, bathing chairs, adaptive car seats, other durable medical equipment, etc.). The pelvic-sacral-lumbar support and/or the thoracic-cervical support may also be used with such mobility devices within the durable medical equipment industry. For example, the pelvic-sacral-lumbar supportand/or thoracic-cervical supportmay be pivotally coupled to a frame of a wheelchair or power chair to support a user's pelvis while in the wheelchair. The example cushion or seatdescribed herein may also be used with the wheelchair instead of a traditional cushion or flat seat.

are various views of the example seatand back supports,providing pelvic support and thoracic support, which may be used in the environment depicted in. The seating configurationallows the user to comfortably sit with proper posture while engaging fewer muscles, and thus experiencing less fatigue. The seat configurationincludes the seat portionthat includes a pelvic wellin which the sit bones of the user are positioned and a lower back support (e.g., pelvic-sacral-lumbar support)that supports and lifts the pelvic-sacral-lumbar regionof the user to prevent posterior collapse in the user while the user is sitting. The seat configurationmay also include an upper back support (e.g., thoracic-cervical support), which contacts the thoracic-cervical spineto help create a natural curve of the spine. Additionally, the upper back supportprovides lateral support of the thoracic-cervical spineby cradling at least a portion of the user's lower ribs to stabilize the user in an upright position without requiring the user to engage their lateral core area (e.g., the transverse and oblique abdominal muscles) to hold themselves centered on the back supports. The thoracic-cervical support contacts the thoracic region, specifically the T10-T12 segments of the spine, and provides support to encourage proper alignment of the thoracic-cervical region of the spine. Thus, when properly adjusted, the thoracic-cervical support is capable of reducing anterior tilt/collapse/flexion in the thoracic region and encourages the shoulders to retract, helping the user to maintain an upright alignment. As a result, this configurationencourages the proper seated posture in a user that causes the least amount of pressure and shear pain while sitting; thus providing a comfortable seat for a longer period of time, and thereby reducing muscle imbalances and aiding in reducing back, shoulder, and neck injuries. The placement of the two back supports,creates a natural curve in the lumbar regionof the spinewithout requiring a support to apply pressure specifically to just the lumbar/sacral region. Instead of applying pressure only to the lumbar region of the spine, the upper and lower back supports,support the pelvic-sacral-lumbar region(e.g., the pelvis, the sacrum, and the L4 and L5 spinal segments of the lumbar region) and the thoracic-cervical regionof the spine.

is a partial skeletal cross-sectional view of a user of the example seat configurationdescribed herein. As depicted in, the user's pelvic-sacral-lumbar region is cradled in a pelvic welland the inclined femoral surfaceof the seatand supported by the pelvic-sacral-lumbar supportto achieve the proper posture as described above. The user's thoracic-cervical region is supported by the thoracic-cervical supportto prevent anterior lean, as described above. Additionally,depicts how the example seat configuration described herein allows for proper spinal alignment and disc spacing throughout the length of the user's spine.

are more detailed views of a first example back support (e.g., lower back support, a pelvic-sacral-lumbar support). The example pelvic-sacral-lumbar supportis shaped and oriented to support and lift the pelvic-sacral-lumbar region. The pelvic-sacral-lumbar supportin combination with the first support armshelps align and hold the pelvic-sacral-lumbar regionin a neutral position so that the lower spine(e.g., the lumbar portion of the spine) is urged into a natural curve with the assistance of the iliolumbar ligaments. Thus, the pelvic-sacral-lumbar supportnot only aligns and supports the pelvic-sacral-lumbar region, but also aids in the proper alignment of the user's spine.

The example pelvic-sacral-lumbar supporthas a curved profile, as shown in the perspective view ofand in the top view of. Not only does the pelvic-sacral-lumbar supportcurve inward toward the edges,, but also gradually angles upward as well. Both the inward curve and/or the slight upward angle toward the edges help lift and support the pelvis of the user by making more contact with the user's pelvic-sacral-lumbar regionadjacent to the pelvic bones as compared to a flat pad. All support surfaces in this design are intended to try to reduce peak pressures as much as possible for the majority of users. In other examples, the pelvic-sacral-lumbar supportmay have a different shape or surface contour and/or no surface contour, while still maintaining contact with the user's pelvis. The example pelvic-sacral-lumbar supporthas a substantially continuous curve, but may alternatively have three distinct portions, or may be an even smoother curve or flat. In such examples where the pelvic-sacral-lumbar supportis flat, a memory foam may be used to allow for additional contact with the user's pelvic-sacral-lumbar region. In some example constructions, a back or outer surfaceof the pelvic-sacral-lumbar supportmay have similarly shaped curve, or may not follow the curve of the inner surface of the pelvic-sacral-lumbar support.

In addition to the upward angles toward the edges of the pelvic-sacral-lumbar support, in some examples the entire pelvic-sacral-lumbar supportmay be pretensioned with an upward angle bias (e.g., using a spring or other biasing mechanism) that is reduced in angle as the user sits so that the central part of the pelvic-sacral-lumbar supportappropriately fits the user and also lifts the pelvis and/or pelvic-sacral-lumbar region. That is, the pelvic-sacral-lumbar supportmay be pivotable about a horizontal axis so that the pelvic-sacral-lumbar supportcan pivot to adjust to fit multiple shapes and sizes of users, and an initial position of the pelvic-sacral-lumbar supportis biased with an upward angle. The pelvic-sacral-lumbar supportmay also be adjusted and locked to different angles to fit different sizes of users.

However, in some examples, the pelvic-sacral-lumbar supportis pivotably fixed (e.g., does not pivot about the connection to the support arm). A pivotably fixed pelvic-sacral-lumbar supportmay be easier to manufacture and/or may be more durable because a repetitive stress point is removed from the chair. Additionally, the angle of the pelvic-sacral-lumbar supportthat is comfortable for the majority of users does not significantly change throughout the range of forward and backward motion (e.g., seat depth adjustment, a pelvic angle adjustment) of the pelvic-sacral-lumbar support. The upward bias of the pelvic-sacral-lumbar supportmay be more critical in a chair with a larger range of motion of the pelvic-sacral-lumbar support.

The pelvic-sacral-lumbar supportmay be positioned just above the seatto facilitate the contact with the pelvic-sacral-lumbar region. The curved shape in the transverse plane of the pelvic-sacral-lumbar supportnot only lifts and supports the pelvic-sacral-lumbar region, but also provides lateral stability to prevent the user from leaning to one side or the other, thereby maintaining the user in an upright position. The shape and positioning of the pelvic-sacral-lumbar supportensures that the pelvic-sacral-lumbar regionis maintained in a natural and neutral seated position.

In some example constructions, the pelvic-sacral-lumbar supportis rotationally fixed (e.g., fixed about a horizontal axis, not pivotable). In example constructions in which the pelvic-sacral-lumbar supportis fixed, the upward and inward angles of the edges of the pelvic-sacral-lumbar supportare set such to accommodate as broad a range of body types and sizes as possible. A fixed pelvic-sacral-lumbar supportmay be advantageous in some implementations of the example pelvic-sacral-lumbar support, such as for use in environments where the adjustability/customization of the location of the pelvic-sacral-lumbar supportmay not be feasible (e.g., theater seating, seating on public transit or planes, etc.). Additionally, the fixed pelvic-sacral-lumbar supportmay be used in seating systems where only one back support is desired or feasible.

In alternative example constructions, the pelvic-sacral-lumbar supportis pivotable around a horizontal axis (e.g., an x-axis) at a pivot point(see). A pivotable pelvic-sacral-lumbar supportmore closely matches a posterior shape of a range of unique individuals. Additionally, a pivotable pelvic-sacral-lumbar supportmay facilitate movement of the user within the seating configuration. For example, if the user leans forward to reach an object or backwards to relax, the pelvic-sacral-lumbar supportcan pivot accordingly and stay in supportive contact with the pelvic-sacral-lumbar regionof the user. In example constructions in which the pelvic-sacral-lumbar supportis pivotable, the pelvic-sacral-lumbar supportmay be biased such that the entire pelvic-sacral-lumbar supportis angled slightly upward when no user is sitting in the seat. This bias helps the user sit into the seatwithout interference from the user's garments during ingress and egress from the chair, while also enabling the pelvic-sacral-lumbar supportcomes into matched contact with the pelvic-sacral-lumbar region.

In some example constructions, the height of the pelvic-sacral-lumbar supportrelative to the seatis adjustable. The height of the pelvic-sacral-lumbar supportmay be adjustable by the user to better fit the user's body such that the pelvic-sacral-lumbar supportis substantially in the ideal position to properly support and lift the user's pelvic-sacral-lumbar region. For example, a taller user (e.g., a user above an average height for an adult) may need the pelvic-sacral-lumbar supportat a different relative height than a shorter user (e.g., a user below an average height for an adult). Thus, an adjustable height construction of the pelvic-sacral-lumbar supportenables the pelvic-sacral-lumbar supportto accommodate a broader range of users to effectively lift and support the user's pelvic-sacral-lumbar region. Additionally or alternatively, the pelvic-sacral-lumbar supportmay move from the back of the seat toward the front of the seat to adjust effective seat depth and to accommodate different heights and sizes of users.

The example seating configurationalso includes a second example back support (e.g., a thoracic-cervical support), as show in. The thoracic-cervical supporthelps support the thoracic-cervical regionof the user's spine. The majority of people who sit for extended periods of time ultimately end up in a slumped forward position, particularly in the thoracic-cervical regionof the spine, due to muscle fatigue and/or muscle strain of keeping the thoracic-cervical regionin an upright position. The thoracic-cervical supportis shaped to promote the proper curve in the thoracic-cervical regionof the spine. The thoracic-cervical supportalso supports the scapulas (e.g., shoulder blades) to maintain a proper posture of the shoulders when in a seated position. Similar to the rolling forward of the thoracic-cervical regionwhen sitting, many people roll their shoulders forward rather than keeping them retracted backwards when in a seated position.

In a typical seated position, rolling the shoulders forward is easier than keeping the shoulders back because keeping the shoulders back for an extended period of time creates strain and fatigue in the upper back and shoulder muscles, particularly the rhomboid muscles and the trapezius muscle. The thoracic-cervical supportcontacts the thoracic-cervical region, specifically the T10-T12 segments of the spine, and provides support to encourage proper alignment of the thoracic-cervical region of the spine. Thus, when properly adjusted, the thoracic-cervical supportis capable of preventing anterior lean/tilt/flexion of the thoracic region and encourages the shoulders to retract, helping the user to maintain an upright alignment. This allows the user to be able to sit in a position with proper posture for an extended period of time without muscle fatigue, discomfort, soreness, or muscle pain. The example thoracic-cervical supportmakes it easier for the user to maintain proper posture, thus promoting and enabling good spinal health for extended periods of time. The vestibular system, which controls the position of the body at rest and provides the brain with information relating to motion, head position, and spatial orientation works in tandem with the thoracic-cervical supportto help neutrally align the thoracic region and comfortably position the head. Due to every person's unique sense of their center of balance, each user has the ability to optimize the location of the thoracic-cervical supportto find the proper balance point of their head. A person's sense of balance relies on a series of signals to the brain from several organs and structures in their body. The part of the ear that assists in balance is known as the vestibular system. When a person moves, the vestibular system detects mechanical forces, including gravity, that stimulate the semicircular canals and the otolithic organs (Vestibular System). These organs work with other sensory systems in your body, such as the vision and the musculoskeletal sensory system, to control the position of a person's body at rest or in motion. Without the adjustable thoracic-cervical support, a balance point cannot be achieved for each individual.

The illustrated thoracic-cervical supporthas a substantially trapezoidal shape (e.g., a modified trapezoidal shape with rounded corners and curved edges). The back of the user rests on the center portion. The left and right side portions,are angled inward to contact at least a portion of the user's ribs (e.g., a portion of at least the two lower ribs) to promote lateral stability (i.e., to prevent the user from leaning to one side or the other, thereby maintaining the user in an upright position). Even a slight contact of the ribs is sufficient to laterally support the user.

The left and right angled edges may be substantially straight, but still allow for more movement of the user's arms and shoulders than a typical chair due to the substantially trapezoidal shape of the thoracic-cervical support. Alternatively, the left and right angled edges may have a curved or cutout portion to allow the user to more easily move their arms into a retracted or reaching position (e.g., to reach for something to one side, to stretch, etc.). In either construction, the thoracic-cervical supportprovides support to the scapulas to keep the scapulas pushed in. Specifically, the trapezoidal shape falls within the thoracic cavity of the user. Anything wider than the thoracic cavity will interfere with the arms or elbows of the user, not allowing for full retraction or reach of the arms of the user.

A top edgeof the example thoracic-cervical supportis thicker than the bottom portion of the thoracic-cervical supportand is angled inward. The example top edgehelps promote the correct curvature of the thoracic-cervical spinal region. However, in alternative examples, the top edgemay be the same thickness as the rest of the thoracic-cervical supportand may not be angled forward. In such examples, the thoracic-cervical supportis still effective to support the user's thoracic-cervical regionin a proper seated posture with minimal muscle engagement. Even without the inwardly curved upper edge, the user is able to easily maintain shoulder retraction and the proper curve of their thoracic-cervical spinal regiondue to the pelvic wellin the seatand the pelvic-sacral-lumbar supportproviding the foundation for proper posture for the entire spine.

The example thoracic-cervical supportcan be moved in an inward (anterior) and outward (posterior) direction relative to the seat. Additionally, the thoracic-cervical supportmay have an adjustable height. Preferably, the height adjustment is done through the center support of the chair (e.g., using a telescoping center support that is attached to a back support). However, the height adjustment can be made at the back support(e.g., using multiple different holes through which a pin can be placed, or other similar adjustable feature, to adjust the height of each back supports,). The adjustment allows the thoracic-cervical supportto be positioned in the correct spot to promote proper anatomical alignment of the user without significant engagement of the user's core and back muscles. More specifically, the forward and backward adjustment ensures that the thoracic-cervical supportmaintains proper posture by keeping the user balanced over the pelvic-sacral-lumbar region. The height adjustment ensures that the inwardly angled sides are in contact with at least a portion of the lower ribs and not so high as to make moving the shoulders difficult.

The thoracic-cervical supportmay also pivot about a horizontal axis at a pivot point(see), similar to the pelvic-sacral-lumbar support. This allows the support surface to closely match the shape and angle of user's thoracic region. The thoracic-cervical supportbeing pivotable also allows the thoracic-cervical supportto accommodate a wider range of body types and sizes. Pivotability additionally helps the thoracic-cervical supportmaintain contact with the user when the user makes slight movements or adjustments while sitting in the chair. The pivotability of the thoracic-cervical supportalso helps maintain contact while trying to achieve balance point and seat comfort, including proper extension (decompression) of the spine.

To further aid in proper pelvic-sacral-lumbar support and alignment, the example seating configurationincludes a seatwith the pelvic welland inclined femoral surfaceformed in the structure of the seat, as shown in. The pelvic wellintegrated into the seatand/or seat cushion creates a space in the seatin which the pelvic-sacral-lumbar region, specifically the ischial tuberosity (or sit bones), rests. The pelvic wellis created in the seatsuch that the pelvic wellis a more natural fit to the human shape, thus reducing peak pressures of the user's IT's by generally redistributing pressures throughout the sitting surface area. The pelvic welland inclined femoral surfacealso position the user's pelvic-sacral-lumbarin an appropriate position such that the pelvic-sacral-lumbar supportis able to make contact with the pelvic-sacral-lumbar region and give the user proper support.

In the example construction depicted in, the pelvic welland inclined femoral surfaceare molded into the material of the seat. In an example of the seatbeing implemented in a cushioned chair or seat (e.g., an office chair, a tractor seat, etc.) the cushion may be made of a foam or other material, such as gel, and the pelvic welland inclined femoral surfaceare molded into the desired shape of the seat cushion such that the peak pressures on the ITs are below 100 mmHg. A foam seat cushion may be an injection molded foam cushion so that the pelvic wellis built-into the construction of the cushion. The foam seat cushion may also be cut from a uniform block of foam in which the pelvic wellis further cut. An example construction of the seatwithout a cushion (e.g., a plastic seat) may also include a pelvic wellmolded (e.g., injection molded) into the material of the seat.

The pelvic wellis positioned adjacent a back edgeof the seatwhere a user's pelvis would be positioned when the user is sitting in an upright position with proper posture. The example pelvic wellmay have a shape corresponding to a shape of the pelvis and gluteus muscles when in a seated position. For example, sides,(e.g., left and right sides of the pelvic well adjacent left and right sides of the seat) of the pelvic wellmay be curved in a similar manner as a curve of a user's hips and/or gluteus muscles when in a seated position. This side edge/curve extends to a front edgeof the seat, forming an elevated edge along the entire length of each the left and the right sides of the seat. The front edge of the seat is at a height above the pelvic well to create increased pressure on the distal end of the femurs, thus increasing pressure distribution area as well as decreasing pressure on the IT's. A back edge of the pelvic welladjacent to the back edge of the seat may be curved to correspond to a curve of the user's pelvic-sacral-lumbar regionand gluteus muscles, which further increases the pressure distribution area and helps assist the lifting of the pelvis in conjunction with the input from the pelvic-sacral-lumbar support.

The slope toward the pelvic wellencourages the proper placement of the pelvis in the pelvic well. Additionally, the pelvic welland inclined femoral surfacemay help relieve pressure or shear underneath and surrounding the region of the IT's. The shape of the pelvic wellhelps cradle and support the user's lower pelvic region or sitting surface and maintain the position of the user's pelvis on the seatsuch that the pelvic supportcan maintain contact with the pelvic-sacral-lumbar region. Additionally, the pelvic welland inclined femoral surfacehold the user in place on the seat, reducing or preventing sliding of the user while the user is sitting in the seat. Additionally, the left and right edges are raised to help the user position themselves in the center of the seat so that the pelvic-sacral-lumbar and thoracic-cervical supports,can work properly to support the user.

In addition to the pelvic well, the front edge of the seatmay include a reverse tapered edge(e.g., an edge that has a bottom surface that is undercut at an angle). The front edge may be tapered backward to act as a relief cut that more closely follow the popliteal fossa downward along the calf muscle. The relief cut helps mitigate contacting these areas, thus reducing the chance of restricting blood flow to one's lower extremities. The design of the front edge of the support surface allows the front edge of the seat to collapse under the weight of the user's legs without the edge of the seat pan contacting and causing pressure on the user's lower extremities. The front edge of the seat pan may also be as low as possible to allow plenty of space for the foam to crush under the weight of the user's legs without coming in contact of the hard front edge, which would cause a sharp pressure to the user's skin that could lead to a pressure injury. Alternatively, the front edge of the seat may be rounded, squared off, or a waterfall edge.

depicts a representation of the forces acting on a user while sitting, including the counteracting forces provided by the seat configuration described herein. Similar to the force diagram shown in, the forces include gravity (G), pressure (e.g., the peak pressures on the IT's) (P), and shear stress(S). In the example construction, the forces acting on the user while sitting are represented using solid arrows. Counteracting forces, or balancing forces are represented using dashed arrows. The example seat configurationdescribed herein counteracts the pressure and shear forces in all seating surfaces, the shear strain in all seating surfaces, and provides the user the opportunity to achieve postural alignment with little discomfort over time. Thus, the example seat configuration results in a reduced triggering of the nociceptors to achieve comfortable sitting for the user over long periods of time.

One or more of the disclosed embodiments, alone or in combination, may provide one or more technical effects including promoting proper ergonomic posture in a way that is comfortable for extended periods of time for a user sitting in a seat configuration described herein. The technical effects and technical problems in the specification are exemplary and are not limiting. It should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems.

As utilized herein, the terms “approximately,” “about,” “substantially,” and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims.

It should be noted that references to relative positions (e.g., “top” and “bottom,” “left” and “right”) in this description are merely used to identify various elements as are oriented in the Figures. It should be recognized that the orientation of particular components may vary greatly depending on the application in which they are used.

For the purpose of this disclosure, the term “coupled” means the joining of two members directly or indirectly to one another. Such joining may be stationary in nature or moveable in nature. Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. Such joining may be permanent in nature or may be removable or releasable in nature.

It is also important to note that the construction and arrangement of the system, methods, and devices as shown in the various examples of embodiments is illustrative only, and not limiting. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many various alternatives, modifications, variations, improvements and/or substantial equivalents, whether known or that are or may be presently foreseen, are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements show as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied (e.g. by variations in the number of engagement slots or size of the engagement slots or type of engagement). The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the various examples of embodiments without departing from the spirit or scope of the present inventions. Therefore, the invention is intended to embrace all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents.