Half-sitting stool with supported sit bone

A seating apparatus for supporting a portion of a user, the seating apparatus comprising a reorientable seat portion including a seat platform and a cutout, wherein the seat selectively underlies a first ischial tuberosity of the user but not the second ischial tuberosity, the selection of which is determined by the orientation of the reorientable seat portion.

FIELD

The present disclosure relates to chairs, stools, sitting devices, standing devices, leaning devices and body-support devices. In particular, the present disclosure relates to a piece of furniture that serves as a substitute to office chairs, task chairs, stools, leaning chairs, perching chairs, and hybrids of such.

BACKGROUND

Well-designed sitting devices that account for ergonomic factors should promote good posture to minimize strain in the neck and back and should allow for periodic adjustments in the user's position to redistribute stresses, relieve pressure points, and allow blood flow through areas where blood flow has been constricted.

Good posture can be generally defined as posture in which the spine maintains neutral curvature, with normal lordotic (“inward”) curvature of the cervical and lumbar spine and normal kyphotic (“outward”) curvature of the thoracic spine. Deviation from neutral curvature, as occurs when one is slumping, creates an aesthetically unappealing appearance and causes shear stresses between vertebra. Shear stresses are increased as deviation is increased, or as load is increased. Shear stresses can trigger pain in people sensitive to such stresses, especially in those who have had previous spinal injuries. Lower back pain, for example, is a common cause of missed workdays in the United States.

Maintaining a neutral lumbar spine requires the least effort in the core muscles when a thigh is at an angle close to 180 degrees relative to the back (e.g. when standing). For this reason, posture is often better when a person is standing than when he or she is sitting. However, standing requires muscular effort to keep the leg extended and to balance the body (since bipedal standing is not inherently stable). To reduce the effort required when stationary, numerous devices are used, such as chairs. But chairs put the thighs at an angle less than 180 degrees (often approximately 90 degrees) in relation to the back, causing a flexion force in the lumbar spine, the flexion force increasing with decreasing back-thigh angle. Unwanted flexion can be counteracted by using the core muscles to maintain normal lordosis of the lumbar spine; such use of core muscles is present when one is, for example, “sitting up straight”. However, prolonged exertion of core muscles can cause fatigue, which hinders the person's ability to continue maintaining good posture.

Many devices are available that attempt to improve sitting posture or to reduce time spent sitting.

Lumbar-support devices apply an external force to the lumbar spine to counteract the flexion force caused by sitting.

Reclining chairs increase back-thigh angle by reclining the back while maintaining the thighs in a horizontal position. They are often accompanied by lumbar-support devices.

Saddle chairs, kneeling chairs, and perching stools increase back-thigh angle by positioning the thighs at a downward angle while allowing the upper body and back to remain vertical, reducing the core-muscle effort required to maintain a neutral spine. They are usually not accompanied by lumbar-support devices.

Leaning chairs create a nearly or fully 180-degree back-thigh angle, reducing or virtually eliminating flexion forces in the lumbar spine.

Sit/stand desks allow the user to alternate between sitting and unsupported standing, allowing for periodic relief of the legs and lower back, respectively.

Each of these devices has disadvantages that the present disclosure does not.

Lumbar-support devices often do not apply enough pressure to the lumbar spine to maintain neutral curvature. They are often used ineffectually, such as when the user does not sit far enough back in the seat pan or when inadequate pressure is applied by the device to the lumbar spine.

Lumbar-support devices, saddle chairs, and kneeling chairs place the user in a fixed position and thus are not conducive to repositioning, which is necessary to redistribute stresses and pressure points, or to promote blood flow.

Saddle chairs put significant pressure on the ischial tuberosities (“sit bones”) and the soft tissue near the sit bones, which can cause discomfort over time.

Kneeling chairs put significant pressure on the knees, which can cause discomfort over time.

Perching stools sometimes require stiff cushions to maintain grip between the user's butt and the seat, to prevent the user from sliding down the seat.

Saddle chairs, kneeling chairs, and perching stools require some core exertion to maintain neutral lumbar lordosis, though less exertion than required by a chair that places the thighs at 90 degrees in relation to the back. Kneeling chairs and perching stools also require leg-muscle exertion to prevent the butt from sliding down the seat.

Reclining chairs require flexion of the upper back or neck to maintain a horizontal head when viewing a screen. Reclining chairs also position the user farther from items on a desk, such as a keyboard, requiring him or her to reach when using such items. Reclining chairs also require a headrest to prevent the head from falling backward. Reclining chairs also make it difficult to read or write on a desk, activities that usually warrant an upright or forward lean of the upper body. Lastly, reclining chairs put the sitter in a more rested position, which can cause drowsiness and reduce attentiveness.

Perching stools and leaning chairs direct a high proportion of the body weight through the legs, stressing the musculature and joints in the legs.

Sit/stand desks require raising and lowering the desk platform, a function that can be expensive to implement and interrupts the user's activity every time the desk platform is translated.

Most methods of sitting, perching, and leaning keep the body symmetrical between the right and left halves. In particular, the back-thigh angle of the right leg is the same as that of the left. However, this need not be the case. For example, U.S. Pat. No. 8,220,872 describes a sitting device in which one leg is in a standing position (i.e. with a 180-degree femur-spine angle) and the other leg in a sitting position (i.e. with a 90-degree femur-spine angle), or in which both legs are in a sitting position. The device has a separate seat pad for each the left and right side which robotically changes angle such that the user can switch standing legs without repositioning the upper body. A disadvantage of this design is that it is complex and potentially expensive to manufacture.

An improved apparatus for sitting/standing satisfies several needs: It enables a 180-degree back-thigh angle; it does not cause extension or flexion of the cervical spine; it eliminates fatigue caused by continuous balancing; it allows periodic rest of leg extensor muscles and relief of pressure points; it allows for positional adjustment with minimal effort; and it is simple in construction.

BRIEF SUMMARY

The present disclosure promotes good posture by enabling the user to extend a leg downward while in a “half-seated” position, in which the user's posture is similar to that of a person who is standing.

The present disclosure vertically supports one side (“supported side”) of the user's pelvis while the other side (“unsupported side”) is vertically supported by the user's standing leg. Having one but not the other side of the pelvis supported by the seat is possible because there is a cutout in the seat through which the standing leg may extend. The seat underlies the sit bone on the supported side of the pelvis but does not underly the sit bone on the unsupported side of the pelvis. The foot on the supported side is placed on a footrest, while the foot on the unsupported side is placed on a base. The weight of the user is therefore distributed among the seat, the footrest, and the base. When the left sit bone but not the right sit bone is supported by the seat, the user is said to be in a “left-seated” position. When the right sit bone but not the left sit bone is supported by the seat, the user is said to be in a “right-seated” position. Stability of the user is enhanced when the user presses back on the seat with the unsupported side of the pelvis, engaging a built-in anti-rotation mechanism (e.g., a mechanical stop, a friction device, etc.) and preventing pelvic rotation in the transverse plane of the user's body. It can be readily inferred that the leg extensor muscles on the supported side are rested, while those on the unsupported side are engaged.

The user may at any time switch the supported and unsupported sides. To do so, the user need only reorient the seat so that the seat underlies the newly supported side and no longer underlies the previously supported side. Therefore, the present disclosure features a seating apparatus that allows for a simple and minimally disruptive way to switch supported and unsupported sides of the pelvis. Reorientation can be rotation, translation, or a combination of the two.

Besides the “left-seated” and “right-seated” positions, the user has other choices of positions: The user may choose a standing position, in which neither sit bones are supported by the seat; the user may choose a conventionally seated position, in which both sit bones are resting on the seat and both feet are resting on a footrest, the base, or the floor; the user may switch to a seated position in which he or she is straddling a saddle integrated into the seat, with both feet on a base or the floor.

DETAILED DESCRIPTION

FIG. 1is an isometric view of a half-sitting stool, consistent with embodiments of the present disclosure.

The half-sitting stool10of the present disclosure includes a seat portion100, supported by a stem portion200, and a base portion300upon which stem portion200is mounted. The seat portion100can rotate relative to the base portion300in the transverse plane of the user. An apparatus enabling orientation of seat portion100relative to base portion300may be located in seat portion100, stem portion200, or base portion300. The distance between seat portion100and base portion300can be adjusted by a height-adjustment mechanism. Also shown inFIG. 1is a footrest portion400that, in some embodiments, is attached to the base portion300and, in other embodiments, is separate from base portion300.

Stem portion200is attached to base portion300so that stem portion200remains upright and does not tip over, even when a leaning force is applied to it. The base portion300may be an apparatus movable relative to the floor, affixed to the floor, or contained in the floor.

FIGS. 2A-2Care isometric views of a half-sitting stool with a user in various seated positions, consistent with embodiments of the present disclosure.FIGS. 2A-2Cshow a general embodiment of the present disclosure with a user900in three positions:

FIG. 2Ashows the user in a left-seated position;

FIG. 2Bshows the user in a right-seated position;

FIG. 2Cshows the user in a conventionally seated position.

FIGS. 2A-2Cillustrate several positions available to the user with minimal effort required to configure the apparatus for the desired position and with minimal transverse movement of the user's torso. It can be seen fromFIG. 2AandFIG. 2Bthat a pseudo-standing posture is possible while simultaneously being supported by the seat. InFIG. 2C, the user assumes a sitting posture because the user is in a conventionally seated position.

To rotate the seat, the user can manually use his/her hands. Alternatively, the user can lower the leg on the supported side, applying backward pressure on the edge of seat100, thereby inducing a transverse torque on seat100that causes it to rotate, while simultaneously raising the leg on the unsupported side, until the seat underlies the pelvis on the previously unsupported side, which becomes the supported side.

In some embodiments, the half-sitting stool may contain a rotational spring which tends to return seat100to a default position (e.g., bias the seat100to a default position, etc.), in addition to or in lieu of an anti-rotation mechanism. Multiple default positions are possible (e.g., a center default position, a left default position, a right default position, etc.)

Although the user ofFIGS. 2A-2Cis shown with an unsupported leg at approximately 180 degrees in relation to the user's torso, the user may have the unsupported leg at less than 180 degrees in relation to the user's torso, in which case the user could be said to be in a leaning position, but the operating principles of the half-sitting stool remain the same.

FIG. 3is an isometric view of the seat platform of the half-sitting stool ofFIG. 1, consistent with embodiments of the present disclosure.FIG. 3shows an embodiment110of seat portion100comprising a seat platform111and a cutout112. Seat platform111vertically supports the user beneath one, the other, both, or neither of the user's ischial tuberosities (i.e., “sit bones”, left ischial tuberosity, right ischial tuberosity, etc.). Cutout112is an empty space (i.e., a void, an opening, etc.) of seat portion110that permits extension of one of the user's legs on the unsupported side downward through cutout112. The seat platform111includes a seat base114that provides structural support to seat portion110and a seat cushion113that distributes pressure applied to the user's buttocks and thereby provides comfort.

The seat platform can have various shapes (when viewed from the top) to accommodate different sizes of people (e.g., a smaller size for smaller adults/kids, a larger size for larger adults/kids, etc.). The specific profile of the seat platform can also be varied. For example, the empty space can have a larger or smaller angle, the size of the saddle portion can be longer/shorter, or wider/narrower.

The 3-D profile of the seat platform (when viewed from the side) can also vary. In the embodiments shown here, the 3-D profile of the seat platform is flat. The 3-D profile of the seat platform can be varied by using different shapes/contours of the seat base and/or the seat cushion.

FIGS. 4A-4Care top views of three orientational positions of the seat platform ofFIGS. 1 and 3, consistent with embodiments of the present disclosure.FIGS. 4A-4Cshow seat platform111from a top view in three orientational positions of seat platform111corresponding to the three seated positions shown inFIGS. 2A-2C. The location of the user's right sit bone111b, the user's left sit bone111c, and the axis of rotation111aare shown for reference. In the preferred embodiment, the axis of rotation111ais stationary, but in other embodiments the axis may move as the seat is rotated.FIG. 4Acorresponds to the left-seated position, in which the left sit bone of the user is underlain and supported by seat platform111while the left sit bone is not;FIG. 4Bcorresponds to the right-seated position, in which the right sit bone of the user is underlain and supported by the seat platform111while the left sit bone is not;FIG. 4Ccorresponds to the conventionally seated position, in which both the left and the right sit bones are supported by the seat platform111. In the left-seated and right-seated positions, the user's sit bones are approximately in the same position. Although seat platform111is flat in the embodiment shown, it can also be shaped, sculpted, molded, or contoured in various shapes for aesthetic, ergonomic, or comfort purposes without change in the function of the apparatus.

Although the changes in orientation of the seat shown inFIGS. 4A-4Care purely rotational, in other embodiments the seat may be translatable in the transverse plane of the user, in which case axis of rotation111ais not stationary and may move up and down or left and right as viewed from above. The function of seat translation may be implemented using a linear slide mechanism, for example. The purpose of enabling seat translation in addition to rotation may be to enhance adjustability of the seat position or to make such adjustment easier to execute.

FIGS. 5A-5Bare isometric views of a stem portion of the half-sitting stool ofFIG. 1, consistent with embodiments of the present disclosure.FIGS. 5A and 5Bshow an embodiment210of stem portion200comprising upper column212and lower column213. In this embodiment, upper column212and lower column213are telescopically movable relative to each other so that the height of seat portion100, which is attached to one of the two columns, can be adjusted relative to the base portion300, which is attached to the other column. The columns are cylindrical and concentric. In various other embodiments, the columns may be non-concentric or have non-round cross sections. Alternative embodiments may include a plurality of columns. In other embodiments still, the apparatus implementing height adjustment may consist of linkages rather than telescoping columns. In any case, the resultant adjustability of height is necessary to accommodate people of various inseam lengths and to accommodate the user's preferred seat height.

Upper column212can include a height-adjustment lever211, an outer cylinder217, and a bushing216. The lower column213can include a gas lift214and a guide rail215. The column length is fixed until the user activates the height-adjustment mechanism by actuating height-adjustment lever211which in turn actuates a pushbutton on gas lift214, permitting gas lift214to extend or retract. Bushing216serves as a linear bushing between outer cylinder217and gas lift214. Bushing216also is used to implement a rotation-limiting function in conjunction with guide rail215.

FIG. 6is a cross-sectional view of a portion of an upper column of the stem portion ofFIGS. 5A-5B, consistent with embodiments of the present disclosure.FIG. 6shows a portion of upper column212from a cross-sectional bottom view. Bushing216is rigidly attached to outer cylinder217, while guide rail215is rigidly attached to gas lift214(not shown inFIG. 6). When upper column212rotates in either direction, bushing216can eventually contacts guide rail215, preventing further rotation. Since upper column212rotates in conjunction with seat portion100and lower column213remains fixed relative to base portion300, rotation of seat portion100relative to base portion300is constrained to a predetermined range. Therefore, when the user is in the left-seated or right-seated position, any tendency for the user's hip to rotate clockwise (as viewed from above) in the former case and counterclockwise in the latter case is restrained, thereby minimizing the need for the user to actively maintain forward hip direction using core and leg muscles. This rotation-limiting function also allows the user to apply a slight backward lean to further promote stability. In other embodiments, the half-sitting stool10may have no anti-rotation mechanism, in which case the disclosure nevertheless supports the pelvis vertically but does not necessarily support the pelvis rotationally.

FIGS. 7A-7Bare isometric views of different base portions for use with a half-sitting stool, consistent with embodiments of the present disclosure.

Base portion300serves as a support for stem portion200and footrest portion400. Base portion300(not shown inFIGS. 7A-7B; seeFIG. 1) also serves to prevent lateral movement of half-sitting stool10relative to the floor.FIGS. 7A and 7Bshow two embodiments of base portion300.

Embodiment310of base portion300(seeFIG. 1) includes a standing surface311, a mount point312for stem portion200, and a mount point313for footrest portion400. In the left-seated and right-seated positions, the user's foot on the unsupported leg rests on standing surface311, while the user's foot on the supported leg rests on footrest portion400. In the standing position, both of the user's feet rest on standing surface311. In the conventionally seated position, the user's feet rest on footrest portion400. Base portion310may be contained in the floor. Base portion310may also be the floor itself, in which case stem portion200and footrest portion400are mounted to the floor.

Embodiment320of base portion300includes a structural frame326that is offset from the floor by a plurality of wheels. Front wheels324are swiveling and rear wheels323non-swiveling. The wheels are mounted to structural frame326. Structural frame326includes mount point321for stem portion200and mount point322for footrest portion400. In the left-seated and right-seated positions, the user's foot on the unsupported side rests on the floor beside structural frame326. In the standing position, both the user's feet rest on the floor beside structural frame326. Embodiment320also includes a brake325that prevents the wheel from spinning when the user applies some weight to half-sitting stool10via seat portion100. The function of brake325is to prevent transverse movement of half-sitting stool10relative to the floor while the user has some of her weight applied to half-sitting stool10.

FIG. 8is an isometric view of a footrest portion for use with a half-sitting stool, consistent with embodiments of the present disclosure.FIG. 8shows an embodiment410of footrest portion400(not shown inFIG. 8; seeFIG. 1). Footrest portion410includes a footrest platform411, a pushbutton412, and a column413. In the left-seated position, the user's left foot is on footrest platform411. In a right-seated position, the user's right foot is on footrest platform411. In a conventionally seated position, both the user's feet are on footrest platform411. Column413is attached to the base portion300and supports the footrest platform411. Column413includes a gas lift that can extend and retract to adjust the height of footrest platform411relative to base portion300. The user raises footrest platform411by pressing pushbutton412with her foot while simultaneously lifting her same foot. The user lowers footrest platform411by pressing pushbutton412with her foot while simultaneously pressing down on footrest platform411. It can be seen that raising and lowering footrest platform411can be done easily with just one foot.

FIGS. 9A-9Care isometric views of different embodiments of the half-sitting stool, consistent with embodiments of the present disclosure. To illustrate some of the possible combinations of seat, stem, base, and footrest,FIGS. 9A-9Cshow three embodiments of half-sitting stool10. Embodiments11and13include seat portion110, while embodiment12includes embodiment120of seat portion100. Seat portion120includes all the elements of seat portion110but also includes a saddle125on which the user can sit in when saddle125is pointed forward. All three embodiments include stem portion210and footrest portion410. Half-sitting stool11includes base portion310; half-sitting stool12includes base portion320; and half-sitting stool13includes embodiment330of base portion300. Base portion330is a floor with mounting points for stem portion200and footrest portion410.FIGS. 9A-9Care meant to provide some examples of combinations of seat, stem, base, and footrest, but it is not practical to show every possible combination here.FIG. 9Cshows an embodiment where there is no separate base—the base is the floor.