A sitting device that gives the user an option to sit with a lower portion of the body supported by a half seat, while maintaining a standing posture with the unsupported leg. The sitting device includes two, left and right, half seats and a foot stool. The device also includes a seat support frame and two half-seat-position-adjusting actuators. The frame includes a horizontal crossbar and a vertical guide tube, wherein the back end of each of the two half seats is pivotally secured on the horizontal bar. The vertical guide tube houses a length-changing mechanism to vary the height of the sitting device and a height fixing mechanism which prevents yielding of the height of the sitting device when the user sits. Also comprising are the two half-seat-position-adjusting actuators attached at one end of each to the vertical tube and at the other end to the respective half seat.

FIELD OF THE INVENTION

The present invention relates to chairs, chair-like devices, body support devices, standing devices, and sitting devices. More specifically, the present invention is a sitting device.

BACKGROUND OF THE INVENTION

According to a study (Deyo et al., 2006), about one fourth of U.S. adults report low back pain in the past 3 months, emphasizing the prevalence and importance of this condition. It is generally accepted that prolonged, static sitting postures are likely to aggravate a preexisting low back condition or instigate the development of a new condition (Kelsey & White, 1980; Lis et al., 2007; Battié´ et al., 2002). Also, a recent occupational study finds that sitting hours positively correlate with lower back pain (Mendelek et al., 2011). In sitting, the pelvis rotates posteriorly and the lumbar lordosis (the natural curve of the lower back) flattens (De Carvalho et al., 2010). This posture increases the strain on the posterior passive elements of the spine (De Carvalho et al., 2010; O'Sullivan et al., 2011; Lengsfeld et al., 2000). The problem stems from the very fact that chair sitting requires raising both upper legs. This reduces the angle between the thigh and the torso from 180 degrees to near 90 degrees therefore pushing the posterior passive elements of the spine (De Carvalho et al., 2010).

There are some claver chair products increasing the thigh-torso angle by providing a knee support and a forward-tilted seat (U.S. Pat. Nos. 4,765,684; 5,782,534), thereby reducing back pain. Another category of products is standing chair (U.S. Pat. Nos. 3,704,847; 4,738,487), by which the user maintains a half-standing posture; sitting on a raised, tilted-forward seat. There are other inventions which let the user change the thigh-torso angle by having two split half seats individually tilt forward (U.S. Pat. Nos. 4,451,086; 7,387,339 B2) or mobilizing the pelvis (U.S. Pat. Nos. 6,139,095; 6,357,827 B1) while the user is in a sitting position. While these products increase the spine-thigh angle, they do not reach the ideal 180 degrees (standing posture); and the postures that the user needs to maintain are rather unnatural.

SUMMARY OF THE INVENTION

The applicant has invented a new category of chair or sitting device, which provides, in one embodiment, two half seats that are individually controlled to be in a supporting seat position or in a collapsed seat position. The sitting device effectively lets the user keep the standing posture while at least half of the body weight supported. Since the standing posture naturally keeps the lumbar lordosis, the sitting device eliminates the source of sitting-related back pain. Moreover, it also gives the user an option to use it as an ordinary chair by positioning both of the two half seats in the supporting position.

In a first embodiment, the sitting device includes two independently position-adjustable half seats. The half seats are secured to the seat support frame comprised of a horizontal cross bar and a vertical guide tube. The piston of a pneumatic cylinder or any equivalent mechanism, which is for height adjustment of the whole sitting device, is housed and travels inside the vertical guide tube of the seat support frame. The bottom of the pneumatic cylinder is secured to the base of the sitting device. At the lower portion of the vertical guide tube of the seat support frame, two perches are attached one for the left half seat-controlling actuator and the other for the right half seat-controlling actuator to be secured on. The bottom of the half seat-controlling linear actuator is secured to the perch via a bracket; the top part of the actuator is secured to the bottom of the half seat via a bracket. The position of each half seat is controlled by the length of the linear actuator, which in turn is controlled by the user via manual switches or by a programmable control box.

A second embodiment of the sitting device shares most of the mechanisms of the first embodiment except for the half seat moving mechanism. In the second embodiment, the linear actuators of the first embodiment are replaced with rotors with attached seat supporting arms, which control the positions of the half seats. Each seat supporting arm has two segments (lower part and upper part) with a joint in the middle. The bottom of the arm is attached to the rotor; the top end of the arm is attached to the bottom of the half seat via a bracket. The position of each half seat is controlled by the angular position of the rotor which in turn swings the attached supporting arm. When the supporting arm swings forward, the attached half seat rises to a supporting position; when the supporting arm swings backward, the attached half seat retracts. This swinging motion is controlled by the user via manual switches or by a programmable control box. Other alternate designs are also presented.

The sitting device of any embodiment may further include one or more of the following: a height fixing mechanism, a backrest or back support member, armrests or arm support member, any structural reinforcement mechanism, casters, a foot stool or foot support member, and any safety mechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is a sitting device whose preferred embodiments are indicated by numbers from 1.000 through 11.000.

FIG. 1shows a lateral view of a first embodiment of the sitting device where a user sits on one of the half seats,1.200a(a: right; b: left; the same convention is used throughout the text), while standing with his/her unsupported leg. For comfort, a foot stool,1.500, is provided.

In a first embodiment and referring toFIGS. 1-9, the sitting device1.000includes a seat support frame or member,1.300to which the rear end of two half seats (1.200afor the right;1.200b, for the left) are secured; an electric linear actuator1.400a, is linked to a perch1.390ajutting out from the bottom part of the support frame1.300; the seat support frame1.300is supported by a pneumatic cylinder1.600, or an equivalent mechanism, that could change the height of the sitting device via its piston1.610inFIG. 3housed inside of the vertical guide tube part1.320of the support frame1.300. In this preferred embodiment, the pneumatic cylinder1.600is a non-rotating one to prevent a pivoting motion of the sitting device around the cylinder. A wider chair base of1.700may be required if a rotating mechanism around the pneumatic cylinder is allowed. A pivoting motion of the whole chair can be achieved via a turn table mechanism embedded in the chair base1.700.

FIG. 2shows a front view of the sitting device inFIG. 1. One half seat has been removed for clarity; the base part of the sitting device is illustrated as an environmental view to give a 3D sense; the same holds for the following figures. The position of the half seat1.200ais controlled by a linear actuator1.400a. The bottom of the actuator is linked to a perch1.390avia a bracket1.391a(FIG. 3) and the top is linked to the bottom of the half seat via a bracket1.420a. When the piston of the actuator1.410alengthens it pushes the bottom of the half seat1.200atherefore raises the half seat in a pivoting motion around the hinge1.311a(FIG. 3) to a supporting position as shown inFIGS. 1 and 2. The illustration also includes a back support1.800and a chair base1.700among other possible chair mechanisms.

FIG. 3shows an exploded, perspective view of a height adjustment mechanism of a sitting device according to the present invention. The seat supporting frame is comprised of a horizontal crossbar1.310, a vertical guide tube1.320and two perches1.390a,1.390bwith brackets1.391a,1.391b, accepting the linear actuators1.400aand1.400b(inFIG. 6). The crossbar1.310accepts the two half seats via the hinges1.311a,1.311b. A pneumatic cylinder1.600or other compatible height changing mechanism is inserted through the bottom of the guide tube. By lifting the height adjusting lever1.312, which pushes the gas releasing button1.611on top of the piston1.610of the pneumatic cylinder, the piston1.610changes its position, therefore pushing or pulling the seat supporting frame1.300, in turn changing the height of the sitting device. At the bottom of the vertical guide tube, a band brake1.330(FIG. 4) or other height fixing mechanism is housed to fix the height. Fixing the height is needed because the height of the sitting device needs to be stable to match the height of the user without yielding.

FIG. 4shows a more detailed height-adjusting mechanism. The figure illustrates a cross-section of the seat supporting frame comprised of a horizontal crossbar1.310and a vertical guide tube1.320. For clarity, the band-brake1.330and the pneumatic cylinder comprised of the piston1.610and its casing1.600are not sectioned. The crossbar1.310houses a spring-loaded height-adjusting lever1.312. The top part of the guide tube1.320secures a socket1.620that secures the top of the piston1.610of the pneumatic cylinder1.600or any equivalent length-changing mechanism. The casing of a band brake1.330or equivalent height-fixing mechanism is secured at the bottom of the guide tube1.320. The casing of the pneumatic cylinder1.600glides through the band brake1.330when the height is allowed to vary. The cable of the band brake1.314links the height-adjusting lever1.312and the band brake1.330and is protected by its case1.316. The left panel ofFIG. 4shows the configuration of the height-adjusting mechanism when it is not in operation. During this non-height adjusting state, the spring1.315pulls the lever1.312down-ward and the cable of the band brake1.314is in a high tension pulled state, which in turn makes the band brake1.330chock the pneumatic cylinder casing1.600therefore fixing the height of the sitting device. The right panel inFIG. 4shows the configuration of the height adjusting mechanism when it is in operation. When the height adjusting lever1.312is pushed up, as indicated by an up-ward arrow in the right panel ofFIG. 4, the lever pivots around its pivot1.313. This lifting motion makes the cable of the band brake1.314relax which in turn makes the band brake1.330release its grip on the pneumatic cylinder casing1.600. After relaxing this height-fixing mechanism, the other end of the height adjusting lever pivots further down now pushing the gas-releasing button1.611on top of the piston of the pneumatic cylinder1.610. This action in turn varies the length of the pneumatic cylinder and therefore the height of the sitting device. When the height-adjusting lever1.312is released, the lever first releases the gas-releasing button1.611therefore stopping the motion of the pneumatic cylinder and then pulls the cable1.314of the band brake1.330to fix the height. In summary, the lifting motion of the height-adjusting lever, by the user, 1) disables the height fix by releasing the grip of the band brake around the pneumatic cylinder and then; 2) engages height adjustment by pressing the gas-release button on top of the pneumatic cylinder. When the height-adjusting lever is released from the lifted position, it 1) disables the height changing mechanism by releasing the gas-releasing button on top of the pneumatic cylinder and then; 2) fixes the height by pulling the cable of the band brake.

FIGS. 5 and 6show a front and lateral views of another side of the first embodiment of the sitting device. When the piston (hidden in the figure) of the actuator1.400bretracts, it leads the half seat1.200bto a collapsed position, as illustrated inFIGS. 5 and 6, in a pivoting motion (indicated by a curved arrow) around the hinge1.311b. InFIGS. 5 and 6, one half seat has been removed for clarity.

FIG. 7illustrates an example of a sequence of motions by the first embodiment of the sitting device. The user can use a control box1.900illustrated inFIG. 8to control the positions and sequence of positions of the half seats as he/she desires. The control box provides a manual panel1.910and an automatic panel1.920. When desired, the user can manually control the position of each half seat individually using the 4 buttons (left seat up, left seat down, right seat up, right seat down) in the “Manual” panel1.910, or program how frequently the seat positions need to change using the buttons in the Automatic panel1.920. The automatic panel provides 5 buttons as illustrated in1.920. The “Cycle on/off” button disables or enables the programmed cycle of seat position sequence. The other 4 buttons (1.921˜1.924) each having an icon corresponding to a configuration of the two half seats provide a means to set a sequence of seat positions. When one of these buttons is pressed, the number (representing minutes) or “N/A” (representing “disabled position”) indicated at the nearest part of the display panel1.925changes to another value (e.g., pressing the button1.921will increase the displayed number from 5 to 6). Each number indicates how long the configuration of the half seat positions should last. For example, the number 5 in the display panel1.925indicates that the configuration of “right half seat supporting and left half seat collapsed” should last 5 minutes before going to the next seat configuration. When one of these buttons is pressed the associated number on the display panel changes in a rotating manner: 0→1→2→ . . . 60→N/A→0, covering an hour. According to this scenario, the display panel1.925inFIG. 8shows a set of sequence of seat configurations (5, 3, 7, N/A) corresponding to the ones inFIG. 7; namely, 5 minutes of A (right side of the user gets supported; left leg standing), 3 minutes of C (the user freely stands with two legs) and 7 minutes of E (the left side of the user gets supported; right leg standing). If desired, the user can push the button1.924to include the normal sitting position (shown in the left panel ofFIG. 9) in the sequence. The electric circuit further includes the power supply1.421and the actuators1.400a,1.400b. The figures of B and D inFIG. 7illustrate transient positions of the moving half seats.

FIG. 9left panel shows a configuration of the second embodiment of the sitting device, in which both of the half seats are in supporting position. When the height is lowered in combination with the raised half seats, the sitting device becomes an ordinary chair as illustrated in the right panel ofFIG. 9.

FIGS. 10 to 14illustrate a second preferred embodiment of the sitting device.FIG. 10andFIG. 11show a side view and a front view of the second preferred embodiment of the sitting device2.000. For clarity, one half seat has been removed. Most of the mechanisms of the second embodiment of the sitting device are the same as the ones of the first embodiment except for the half seat moving mechanism. The second embodiment uses two swinging-motion seat supporting arms each one comprised of the lower part2.400(a right, b left) and the upper part2.410(a right, b left), in contrast to the linear actuator1.400described in the first preferred embodiment. The lower part2.400and the upper part2.410of the seat supporting arm are linked by a shock absorber2.420(a right, b left). The bottom of the lower part of the seat support arm2.400is attached to a slowly moving rotor2.391(a right, b left), which is in turn secured to a perch2.390(a right, b left). When the rotor2.391binFIG. 10spins clockwise the lower part of the half seat-supporting arm swings backward as illustrated by a curved arrow. This motion is equivalent to a movement of a human arm bending inward from a stretched position, as illustrated in the inset figure. This motion of the half-seat-supporting arm leads the attached half seat2.200bto a retracted position.

FIGS. 12 and 13show a side view and a front view of the second preferred embodiment of the sitting device, respectively. When the lower part of the supporting arm2.400aswings forward, indicated by a curved arrow, due to a rotating motion of the rotor2.391a, the supporting arm extends (or straightens) just like a stretching human arm from a bent position therefore pushing the half chair2.200ato a supporting position. The inset shows the configuration of the joint portion2.400jof the lower and upper parts of the support arm. For a better illustration it shows magnified and disjointed parts. The configuration of the joint prevents the angle of the arm from going beyond 180 degrees, just like a human arm that cannot be bent outward, i.e., locks (for axial force) when straight. The inset of theFIG. 13shows the configuration of the joint2.400jfrom another view point. This configuration allows the supporting arm to lock naturally when it is stretched just like a human arm.

The locked supporting arm as illustrated inFIG. 12becomes unlocked during the retraction of the half seat because the supporting arm bends. Without a motion damping mechanism, this will make the half seat collapse too quickly under the user's weight. To prevent this sudden yielding of the position of the half seat, a shock absorber2.420a(b for the left) is attached linking the lower part2.400aand upper part2.410aof the supporting arm. While the supporting arm of this embodiment uses only two segments (lower part and upper part), many more segments can also be used. This may give a better retracting motion and also reduce the length that juts out backside of the chair when the half seat is in a retracted position.

The left panel ofFIG. 14is a perspective view of the second embodiment with one half seat raised and the other retracted. The right panel ofFIG. 14is a perspective view of the second embodiment having a configuration similar to the one inFIG. 9right pane. When both of the half seats are in the supporting position they form a full seat and the sitting device can be used as an ordinary chair.

FIGS. 15 and 16show a third preferred embodiment of the invention,3.000, with heavy duty design using two supporting columns. This embodiment is an adaptation of the first embodiment1.000(could be of the second one,2.000) with two flanking supporting columns3.341a,3.341band two guide tubes3.340a,3.340bthat glide along the corresponding supporting columns. Armrests3.345a,3.345bare secured at the top portion of the guide tubes3.340aand3.340b. The middle column of the sitting device, which houses the height adjustment mechanism, is connected to the two guide tubes3.340a,3.340bby two horizontal crossbars,3.310,3.390. The upper crossbar3.310secures the two half seats3.200a,3.200b; the lower crossbar3.390secures the bottom of the two actuators3.400a,3.400bcontrolling the half seats. This reinforced design prevents the sitting device from a pitching motion when the half seats3.200aand/or3.200bare in supporting position and receive a heavy load.

The height adjustment mechanism of the third embodiment of the sitting device is similar to the ones in the first and second embodiments of the sitting device where the piston (similar to the one,1.610, inFIG. 3) of the pneumatic cylinder3.600extends or retracts causing the height of the device to vary. As the height of the sitting device goes up or down, the guide tubes3.340aand3.340bwill glide up or down along the corresponding supporting columns3.341aand3.341b, respectively. One example of a different sitting height is illustrated inFIG. 16where the piston of the pneumatic cylinder has fully retracted therefore lowering the sitting position of the device3.000, transforming the device into an ordinary chair.

The half seat raising/folding mechanism can be achieved using other alternative mechanisms. One non-limiting example (fourth embodiment) is given in the upper portion ofFIG. 17. This embodiment shows an unfolding motion of a half seat,4.200a, comprising 3 small segments, rising (to the right in the figure) or retracting (to the left in the figure) segment by segment in a sweeping motion. Different number of segments, or a flexible material without segments (or a hybrid including both) can be used for a smoother motion. For a comparison purpose, a corresponding swinging motion of one monolithic half seat,1.200a, used in the first preferred embodiment of the sitting device, is shown in the lower portion ofFIG. 17. This gradual unfolding of the seat illustrated in the upper portion ofFIG. 17may achieve a less intrusive motion for the user than the one illustrated in the lower portion ofFIG. 17. Only the moving components of the half seat are shown for clarity.

FIG. 18shows a fifth embodiment of the sitting device,5.000; only the half seat configurations are shown for clarity. This embodiment includes two half seats,5.200a,5.200b, statically raised (i.e., no actuator-driven half seat raising/lowering mechanism is assumed) with a gap in between. The user manually changes his position to sit on the right half seat or left half seat while maintaining a standing posture with the unsupported leg; one example is illustrated in the left panel ofFIG. 18. The gap can be closed by bring the two halves5.200a,5.200bcloser together in a linear motion (as illustrated by the two opposing arrows in the right panel inFIG. 18) forming a full seat. This linear motion can be achieved manually or automatically.

FIG. 19shows a sixth embodiment of the sitting device,6.000; only the half seat configurations are shown for clarity. This embodiment includes two half seats6.200a,6.200bstatically raised. The user manually changes his position to sit on the right half seat or left half seat while maintaining a standing posture with the unsupported leg. The two separated and statically raised half seats6.200a,6.200bcan be brought together by a pivoting motion as illustrated by two curved and opposing arrows along a pivoting axis (illustrated by a vertical broken line on the right panel ofFIG. 19) to form a full seat. This pivoting motion can be achieved manually or automatically.

FIG. 20shows a seventh embodiment of the sitting device,7.000; only the half seat configurations are shown for clarity. The embodiment includes two half seats7.200a,7.200bwhose positions are individually controlled along the two fronto-caudal rotating axes on the left and right side of the user who is in the middle of them. This rotating motion, illustrated as arrows, can be achieved manually or automatically.

FIG. 21shows an eighth embodiment of the sitting device,8.000; only the seat configurations are shown for clarity. The embodiment includes a statically raised full seat8.200aand a statically raised half seat8.200b(may be foldable or removable manually) with a gap in between. The user maneuvers to switch his/her positions between the two seats as desired.

FIG. 22shows a ninth embodiment of the sitting device,9.000; only the essential parts are shown for clarity. InFIG. 22, the left panel illustrates a side view of a raised half seat9.200a, attached rotor9.311aand its extended arm9.312asupporting the half seat. The middle panel illustrates a perspective view of the raised and folded half seats9.200aand9.200balong with the seat support frame9.310, pneumatic column9.600and the chair base. The right panel illustrates a side view of a retracted half seat9.200b, attached rotor9.311band its extended arm9.312bsupporting the half seat. In this design, the actuators that raise the half seats are encased inside the crossbar9.310of the seat support frame therefore exposing no damageable moving parts of the actuating mechanism. It is assumed to have a similar height adjusting mechanism as the one used in the first and second embodiment of the sifting device, except the height adjusting lever needs to be somewhere in the middle portion of the seat support frame9.310because the lateral parts of the crossbar9.310are occupied by the rotors. One side rotor9.311a, is connected to the corresponding half seat9.200avia the connected arm9.312aand the other side rotor9.311bis connected to the other half seat9.200bvia the connected arm9.312b. When a rotor9.311arotates anticlockwise, illustrated as upward-curved arrows in the left and middle panels ofFIG. 22, the attached half seat9.200arises to a supporting position. When the rotor9.311brotates anticlockwise, illustrated as downward-curved arrows in the middle and right panels ofFIG. 22, the attached half seat9.200bretracts. Each rotor is driven by a corresponding motor-gear-brake assembly (similar to the ones commonly seen in all-terrain-vehicle electric winches) fit inside of the crossbar9.310. Namely, the right side motor-gear-brake assembly rotating the rotor9.311ais encased inside and right side of the crossbar9.310; and the left side motor-gear-brake assembly rotating the rotor9.311bis encased inside and left side of the crossbar9.310. Each rotor is a cylinder connected to the underlying corresponding motor-gear-brake assembly. The high torque motor-gear-brake assembly slowly rotates the attached cylindrical rotor (9.311ain case of right side) therefore rotating the attached half seat (e.g.,9.200a). A controller mechanism similar to the one illustrated inFIG. 8(with the two linear actuators,1.400a,1400b, replaced with the two motor-gear-brake assembly) is used to drive the two motor-gear-brake assemblies and control their motion.

FIG. 23shows a tenth embodiment of the sitting device,10.000. The left panel ofFIG. 23shows a perspective view of a half seat in a retracted position, and the right panel shows a perspective view of the same half seat in a raised position. Only one side of the half-seat-position-adjusting mechanism is shown for clarity. This embodiment includes a cable10.401b; a pulley10.402b; a motor10.400bthat pulls or releases the cable; and a half seat10.200bwhose backend is attached preferably to the seat support frame (not shown and assumed a similar configuration as the one used in the first embodiment of the sitting device) via a hinge10.311b. When one end of the cable10.401bis pulled down, illustrated as a downward arrow on the right panel, the other side of the cable, whose end is attached to the half seat10.200bvia a link10.201bgets pulled upward, illustrated as an upward arrow. This upward motion of the cable raises the half seat, illustrated as an upward curved arrow. The pulley mechanism may be housed in or around the armrest.

FIG. 24shows an eleventh embodiment of the sitting device,11.000; only one side of the half seat raising mechanism is shown for clarity. This embodiment includes a supporting beam11.400b, a half seat11.200band the seat support frame11.310. When the moving supporting beam11.400btravels forward (from the left-most figure to the right-most figure) it pushes the retracted half seat to a raised position (right-most panel). A backward travel motion will let the half seat go back to the retracted position (left-most panel). The supporting beam is supposed to be able to adjust its height to match the seat height that the user sets.

REFERENCES CITED

Academic Journals

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UNITED STATES PATENTS