Chair tilt mechanism

CROSS-REFERENCE TO RELATED APPLICATIONS

0001The present application claims priority to <patcit id="pcit0001" dnum="US24235419" dnum-type="L"><text>U.S. Patent Application No. 16/242,354, filed on January 8, 2019</text></patcit> and <patcit id="pcit0002" dnum="US62620196" dnum-type="L"><text>U.S. Provisional Patent Application No. 62/620,196, which was filed on January 22, 2018</text></patcit>.

FIELD OF INVENTION

0002The present invention relates to chairs, tilt mechanisms for chairs, and methods of using chairs.

BACKGROUND OF THE INVENTION

0003Chairs often include a base that supports a seat. Examples of chairs may be appreciated from <patcit id="pcit0003" dnum="US8216416B"><text>U.S. Pat. Nos. 8,216,416</text></patcit>, <patcit id="pcit0004" dnum="US8167373B"><text>8,167,373</text></patcit>, <patcit id="pcit0005" dnum="US8157329B"><text>8,157,329</text></patcit>, <patcit id="pcit0006" dnum="US8029060B"><text>8,029,060</text></patcit>, <patcit id="pcit0007" dnum="US7887131B"><text>7,887,131</text></patcit>, <patcit id="pcit0008" dnum="US7198329B"><text>7,198,329</text></patcit>, <patcit id="pcit0009" dnum="US6824218B"><text>6,824,218</text></patcit>, and <patcit id="pcit0010" dnum="US6817667B"><text>6,817,667</text></patcit> and <patcit id="pcit0011" dnum="US20030168901"><text>U.S. Pat. App. Pub. Nos. 2003/0168901</text></patcit>, <patcit id="pcit0012" dnum="US20060006715"><text>2006/0006715</text></patcit>, and <patcit id="pcit0013" dnum="US20080290712"><text>2008/0290712</text></patcit>. Some chairs may be configured to have a back that tilts from an upright position to a recline position. Other relevant chairs are disclosed in <patcit id="pcit0014" dnum="EP0535262A1"><text>EP0535262A1</text></patcit> and <patcit id="pcit0015" dnum="US3053571A"><text>US3053571A</text></patcit>.

SUMMARY OF THE INVENTION

0004In an aspect of the invention, there is provided a chair as claimed in claim 1.

0005The spring of the tilt mechanism can be a coil spring, an elastomeric spring or other type of spring. In some embodiments, the spring can be a coil spring that is positioned around a gas spring within the column that is actuatable for height adjustment of the seat. The gas spring can be positioned within the central opening of the coil spring that extends along the length of the coil spring. The central opening can be defined by the body of the coil spring as an inner passageway that extends along the length of the coil spring.

0006The frame of the backrest can have more than just a first leg. For example, the frame of the backrest can include a second leg that extends forwardly form the lower portion to a position below the seat that is within a housing of a tilt mechanism. The tilt mechanism can also include elements for connecting to the second leg. For example, the tilt mechanism can include a second spring connecting member that has a lower end connected to the spring and an upper end pivotally connected to a first end of a third tilt member. A second end of the third tilt member can be pivotally connected to a second end of a fourth tilt member. A first end of the fourth tilt member can be pivotally connected to a portion of a forward distal end of the second leg extending from the lower portion of the frame of the backrest.

0007The tilt mechanism can include a leverage adjustment mechanism. The leverage adjustment mechanism can include a leverage adjustment actuator connected to a rotatable member. The rotatable member can be connected to a first node positioning member so that rotation of the rotatable member in a first rotational direction drives linear motion of the first node positioning member in a forward direction and rotation of the rotatable member in a second rotational direction that is opposite the first rotational direction drives motion of the first node positioning member in a rearward direction. The rotatable member can also be connected to a second node positioning member so that rotation of the rotatable member in the first rotational direction drives linear motion of the second node positioning member in a forward direction and rotation of the rotatable member in the second rotational direction drives motion of the second node positioning member in a rearward direction. A first node can be provided that engages the first tilt member. The first node can be attached to the first node positioning member such that the first node moves forwardly when the first node positioning member is moved forwardly via rotation of the rotatable member in the first rotational direction and the first node moves rearwardly when the first node positioning member is moved rearwardly via rotation of the rotatable member in the second rotational direction. A second node that engages the third tilt member can also be provided. The second node can be attached to the second node positioning member such that the second node moves forwardly when the second node positioning member is moved forwardly via rotation of the rotatable member in the first rotational direction and the second node moves rearwardly when the second node positioning member is moved rearwardly via rotation of the rotatable member in the second rotational direction. The first and second nodes can be positioned so that motion of the first node and second node can adjust a mechanical leverage applicable to the spring to adjust an amount of force needed to be exerted on the backrest to compress the spring.

0008Embodiments of the chair can also include a tilt limiter mechanism. For example, some embodiments can include a tilt limiter mechanism that includes an adjustable actuator connected to a tilt limiter member within the housing of the tilt mechanism. The tilt limiter member can be positioned within a slot defined by structure within the housing of the tilt mechanism such that movement of the actuator adjusts a position of the tilt limiter member within the slot.

0009As another example, a tilt limiter mechanism can include an adjustable actuator connected to a tilt limiter member within the housing of the tilt mechanism where the tilt limiter member is moveably positioned to engage the first tilt member. The tilt limiter member can be stepped so that a first position of the tilt limiter member prevents recline of the backrest, a second position of the tilt limiter permits the first tilt member to move so that the backrest is adjustable from the upright position toward the reclined position, and a third position of the tilt limiter permits the first tilt member to move so that the backrest is moveable to a position that is between the upright position and the reclined position. Embodiments of the tilt limiter mechanism can also include a shaft positioned within a slot. The shaft can be connected to the tilt limiter member such that the shaft is moveable within the slot when a position of the tilt limiter member is adjusted. The tilt limiter mechanism can also include a first spring that is configured to facilitate movement of the actuator of the tilt limiter mechanism and a second spring that is configured to provide a pre-selected biasing force to prevent adjustment of the tilt limiter member when the backrest is in the reclined position. The second spring can be positioned so that the second spring is connected to the tilt limiter member so that the second spring moves in response to the actuator of the tilt limiter mechanism being adjusted only when the backrest is in the upright position to effect motion of the tilt limiter member in response to movement of the actuator.

0010Embodiments of the chair can utilize a tilt mechanism that includes a leverage adjustment mechanism. Some embodiments of the leverage adjustment mechanism can include a leverage adjustment actuator connected to a rotatable member. The rotatable member can be connected to a node positioning member so that rotation of the rotatable member in a first rotational direction drives linear motion of the node positioning member in a forward direction and rotation of the rotatable member in a second rotational direction that is opposite the first rotational direction drives motion of the node positioning member in a rearward direction. A node that engages the first tilt member can be attached to the node positioning member such that the node moves forwardly when the node positioning member is moved forwardly via rotation of the rotatable member in the first rotational direction and the node moves rearwardly when the node positioning member is moved rearwardly via rotation of the rotatable member in the second rotational direction. The node can be positioned so that motion of the node to adjust a position of the node adjusts a mechanical leverage applicable to the spring to adjust an amount of force needed to be exerted on the backrest to compress the spring.

0011A method of using a chair is also provided. An embodiment of the chair that is used in the method can be an embodiment of a chair disclosed herein. Some embodiments of the chair can include providing a chair, adjusting a position of a node that engages the first tilt member such that the node moves forwardly or rearwardly to adjust a mechanical leverage applicable to the spring to adjust an amount of force needed to be exerted on the backrest to compress the spring and recline the backrest; and manipulating an actuator of a tilt limiter mechanism of the chair to adjust an extent to which the backrest is reclineable while the backrest is reclined.

0012In some embodiments of the method, the adjusting of the position of the node occurs via the node moving forwardly along a plate of the first tilt member. In other embodiments, the adjusting of the position of the node occurs via the node moving rearwardly along a plate of the first tilt member. In other embodiments, the adjusting can occur via movement of the node forwardly and rearwardly to different positions.

0013Embodiments of the method can also include other steps. For example, an embodiment of the method can include delaying adjustment of the tilt limiter mechanism to occur via the manipulating of the actuator of the tilt limiter mechanism so that adjustment of the tilt limiter mechanism is only effected after the backrest is moved to the upright position and is no longer reclined. In some embodiments, the delaying adjustment of the tilt limiter mechanism can include a spring of the tilt limiter mechanism having a pre-selected biasing force resiliently moving in response to motion of the actuator of the tilt limiter mechanism when the backrest is reclined to prevent adjustment of a detent mechanism for adjusting a position of the tilt limit member when the backrest is reclined. The pre-selected biasing force can be a force that is less than a force needed to overcome force acting on the tilt limiter mechanism when the backrest is reclined to prevent overloading of components of the chair.

0014Other details, objects, and advantages of the invention will become apparent as the following description of certain present preferred embodiments thereof and certain present preferred methods of practicing the same proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS

0015Exemplary embodiments of the chair and tilt mechanism for the chair are shown in the accompanying drawings. It should be appreciated that like reference numbers used in the drawings may identify like components. <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Figure 1</figref> is a perspective view of a first exemplary embodiment of a chair.</li><li><figref idref="f0002">Figure 2</figref> is a side view of the first exemplary embodiment of the chair.</li><li><figref idref="f0003">Figure 3</figref> is a fragmentary side view of the first exemplary embodiment of the chair.</li><li><figref idref="f0004">Figure 4</figref> is a fragmentary bottom view of the first exemplary embodiment of the chair.</li><li><figref idref="f0005">Figure 5</figref> is a first centered cross sectional view of the first exemplary embodiment of the chair in an upright position with the tilt mechanism in a first lower tension position.</li><li><figref idref="f0006">Figure 6</figref> is a second off-center cross sectional view of the first exemplary embodiment of the chair in an upright position with the tilt mechanism in a first lower tension position.</li><li><figref idref="f0007">Figure 7</figref> is a third cross sectional view of the first exemplary embodiment of the chair in an upright position with the tilt mechanism in a first lower tension position and with parts hidden to better illustrate portions of the mechanism.</li><li><figref idref="f0008">Figure 8</figref> is a first centered cross sectional view of the first exemplary embodiment of the chair in a reclined position with the tilt mechanism in a first lower tension position.</li><li><figref idref="f0009">Figure 9</figref> is a second off-center cross sectional view of the first exemplary embodiment of the chair in a reclined position with the tilt mechanism in a first lower tension position.</li><li><figref idref="f0010">Figure 10</figref> is a third cross sectional view of the first exemplary embodiment of the chair in a reclined position with the tilt mechanism in a first lower tension position and with parts hidden to better illustrate portions of the mechanism.</li><li><figref idref="f0011">Figure 11</figref> is a first centered cross sectional view of the first exemplary embodiment of the chair in an upright position with the tilt mechanism in a second higher tension position.</li><li><figref idref="f0012">Figure 12</figref> is a second off-center cross sectional view of the first exemplary embodiment of the chair in an upright position with the tilt mechanism in a second higher tension position.</li><li><figref idref="f0013">Figure 13</figref> is a third cross sectional view of the first exemplary embodiment of the chair in an upright position with the tilt mechanism in a second higher tension position and with parts hidden to better illustrate portions of the mechanism.</li><li><figref idref="f0014">Figure 14</figref> is a first centered cross sectional view of the first exemplary embodiment of the chair in a reclined position with the tilt mechanism in a second higher tension position.</li><li><figref idref="f0015">Figure 15</figref> is a second off-center cross sectional view of the first exemplary embodiment of the chair in a reclined position with the tilt mechanism in a second higher tension position.</li><li><figref idref="f0016">Figure 16</figref> is a third cross sectional view of the first exemplary embodiment of the chair in a reclined position with the tilt mechanism in a second higher tension position and with parts hidden to better illustrate portions of the mechanism.</li><li><figref idref="f0017">Figure 17</figref> is a schematic image of the first exemplary embodiment of the chair in a reclined position with the tilt mechanism in a lower tension position.</li><li><figref idref="f0018">Figure 18</figref> is a schematic image of the first exemplary embodiment of the chair in a reclined position with the tilt mechanism in a higher tension position.</li><li><figref idref="f0019">Figure 19</figref> is a fragmentary perspective view of the first exemplary embodiment of the chair illustrating internal components of the tilt mechanism 10.</li><li><figref idref="f0020">Figure 20</figref> is a fragmentary perspective view of the first exemplary embodiment of the chair illustrating internal components of the tilt mechanism 10.</li><li><figref idref="f0021">Figure 21</figref> is a fragmentary view of an adjustment mechanism of the tilt mechanism 10 of the first exemplary embodiment of the chair in a first position.</li><li><figref idref="f0021">Figure 22</figref> is a fragmentary view of an adjustment mechanism of the tilt mechanism 10 of the first exemplary embodiment of the chair in a second position.</li><li><figref idref="f0022">Figure 23</figref> is a fragmentary side view of the first exemplary embodiment of the chair with portions of the chair cut away to illustrate components of a tilt limiting mechanism.</li><li><figref idref="f0023">Figure 24</figref> is a is a fragmentary side view of the first exemplary embodiment of the chair with portions of the chair cut away to illustrate components of the tilt limiting mechanism in a full travel position.</li><li><figref idref="f0024">Figure 25</figref> is a is a fragmentary side view of the first exemplary embodiment of the chair with portions of the chair cut away to illustrate components of the tilt limiting mechanism in a mid travel position</li><li><figref idref="f0025">Figure 26</figref> is a is a fragmentary side view of the first exemplary embodiment of the chair with portions of the chair cut away to illustrate components of the tilt limiting mechanism in a non-tilting, or non-travel position</li></ul>

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

0016Referring to <figref idref="f0001 f0002 f0003 f0004 f0005 f0006 f0007 f0008 f0009 f0010 f0011 f0012 f0013 f0014 f0015 f0016 f0017 f0018 f0019 f0020 f0021 f0022 f0023 f0024 f0025">Figures 1-26</figref>, a chair 1 can include a base 3 that supports a seat 5 and a backrest 7. The base 3 can be configured as a pedestal base 3b that is supported by rotatable castors that engage the floor and are moveable to allow the base to be slid or wheeled along a floor and includes a vertically extending column 3a. A gas spring can be positioned within a channel 3d defined in the column 3a. The gas spring can extend upwardly from within the column 3a to and/or within a housing 10a for a tilt mechanism 10. The gas spring can be actuatable via an actuator 6 connected to the gas spring to allow for height adjustment of the seat 5 and backrest 7 so that the seat and backrest are vertically moveable relative to the base 3 and floor on which the base can be positioned between uppermost and lowermost positions.

0017A spring 12 can also be positioned within the column 3a inside the vertically extending channel 3. The spring 12 can be a coil spring, an elastomeric elongated spring, or other type of spring element. The spring 12 can be positioned so that it extends within the column 3a outside of the gas spring along a periphery of the gas spring within the column 3a. The gas spring can be within a conduit of the spring 12 (e.g. within a central opening defined by the spring 12, within a central conduit defined by the length of the body of a coil spring when the spring 12 is a coil spring, etc.). In some alternative embodiments, the base 3 can be configured to have a plurality of legs that can have a bottom end that contact the floor or directly engage a floor or are attached to glides that are configured to contact the floor.

0018The chair 1 can include armrests 9 positioned above the seat 5. The armrests 9 can be attached to a portion of the back frame of the backrest 7, a portion of the seat frame of the seat 5, and/or the base 3 so that the armrests 9 are supported above the seat 5. The armrests 9 may be moveable independent of the base 3 and/or backrest 7 or may be affixed to the backrest 7 such that the armrests 9 move in coordination with and simultaneously with the backrest 7 as the backrest 7 moves between an upright position and a reclined position.

0019The seat 5 can include a seat frame 5a that includes a seat plate that may be attached to a tilt mechanism 10 and/or the base 3. The seat frame 5a can help support other seat components (e.g. a seat skin, a cushion covered by a leather or fabric covering, etc.). The seat frame 5a can also include a seat slide mechanism 5b that is configured to permit the seat to be horizontally adjustable along the seat frame 5a independent of the base and backrest so that the seat 5 can be slid forwardly and rearwardly between forward and rearward positions defined by the seat slide mechanism 5b. An actuator 6 can be connected to the slide mechanism so that a user may move the actuator 6 from a locked position to an unlocked position so that the user can exert a force on the seat to effect a horizontal sliding movement along a track defined by the seat slide mechanism 5b. The track can at least be partially defined in a part of the seat frame.

0020The seat 5 and backrest 7 can be coupled to each other via a tilt mechanism 10 so that the backrest 7 can be tilted between an upright position and a reclined position such that the seat 5 synchronously moves as the backrest 7 is moved. Such movement can be appreciated from <figref idref="f0005 f0006 f0007 f0008 f0009 f0010 f0011 f0012 f0013 f0014 f0015 f0016">Figures 5-16</figref>. The tilt mechanism 10 can be configured to bias the backrest 7 to its upright position and the seat 5 to its corresponding first position. The tilt mechanism 10 can also be configured to facilitate motion of the backrest 7 that can be actuated by a user providing a force to push against the backrest while seated in the seat 5 so that the backrest is tiltable to the reclined position and the seat 5 is moveable from its initial first position to a second position that corresponds with the backrest's reclined position. When the user removes the force (e.g. the user stops leaning back on the backrest while seated on the seat 5), the tilt mechanism 10 can effect movement of the backrest 7 from its reclined position to its upright position and also effect motion of the seat 5 from its second position to its first position.

0021The backrest 7 can include a backrest frame that is attached to or supports a back skin that a user may lean his or her back against when seated in the seat 5. The back skin can be a polymeric skin, a mesh skin, or a leather or fabric covering that covers a cushion supported by the backrest frame. The backrest 7 can include an upper portion 7c, a bottom portion 7b and an intermediate portion 7d between the upper portion 7c and lower portion 7b. The lower portion 7b can include a plurality of legs 7a that extend from the lower portion 7b of the backrest frame to the tilt mechanism 10. Each leg 7a can have a distal end 8 positioned in the housing 10a of the tilt mechanism 10 that is pivotally coupled to one or more structures of the tilt mechanism 10. At least a portion of each leg 7a can be enclosed within a side gaiter 3e that is connected to the housing 10a. In some embodiments, a first side gaiter that encloses at least a portion of a first leg 7a can be on a left side of the housing 10a between the front and back of the seat 5 and a second side gaiter can enclose at least a portion of a second leg 7a on a right side of the housing 10a between the front and back of the seat 5. The side gaiters 3e can each be positioned below the seat skin of the seat on which a user can sit. The side gaiters 3e can be attached to the base 3, the tilt mechanism housing 10a and/or the legs 7a. The side gaiters 3e can be positioned and configured to provide an enclosure structure to prevent exposed pinch points from the pivotal couplings of the legs 7a to other structure of the tilt mechanism 10. The side gaiters 3e can at least partially define a channel or passageway in which a respective leg is positioned and can also be composed of a resilient material or elastomeric material so that the gaiters 3e can bend or flex in response to contact with the legs 7a that may occur when the legs 7a tilt or otherwise move as the backrest 7 moves between the upright and reclined positions.

0022The tilt mechanism 10 can include a plurality of interconnected structures. These structures can include a vertically extending spring connecting member 11 that connects the coil spring 12 to the tilt mechanism 10 so that the coil spring 12 is able to provide a biasing force that is exertable on the seat 5 and backrest 7 to bias the backrest to its upright position and the seat 5 to its first position. It should be appreciated that there can be multiple spring connecting members 11 (e.g. a first spring connecting member adjacent a left side of the coil spring and a second spring connecting member adjacent a right side of the coil spring opposite the first spring connecting member). Each spring connecting mechanism can be positioned for operative connection to a respective leg 7a extending from the lower portion 7b of the backrest 7.

0023For each spring connecting member 11, a lower end 11a of the spring connecting member 11 can be connected to the coil spring 12 via a spring connection mechanism and the upper end 1 1b of the spring connecting member 11 can be pivotally connected to a respective first tilt member 21. The spring connection mechanism can be a spring plunger element that is configured so that a force is translatable from the spring connecting member to the spring 12 for pushing the spring 12 into a retracted position (or a compressed position) and to translate a force exerted by the spring 12 when the spring 12 extends from a retracted position, or compressed position. Each first tilt member 21 can extend from a first end 21a that is pivotally connected to the upper end 11b to which it is connected to a second end 21b that is pivotally connected to a second tilt member 23. The second tilt member 23 can extend from its second end 23b that is coupled to the second end 21b of the first tilt member 21 to its first end 23a that is pivotally coupled to the front distal end of the leg 7a via a pivotal connection mechanism 25.

0024The first tilt member 21 can have a plate 15 that extends therefrom. A moveable node 10b can be positioned on the plate 15 that is moveable along the upper surface of the plate 15 between a rear end 16 and a front end 18. The moveable node 10b can be horizontally moveable along an intermediate portion 17 between the front and rear ends 18 and 16 of the plate 15 coupled to the first tilt member 21 or that extends from the first tilt member 21. The movement of the moveable node 10b adjusts the leverage of the biasing force exerted by the coil spring 12 via the spring connecting member 11 and its pivotal connection to the first tilt member 21 as the first member pivots about the pivotal connection at the upper end 11b of the spring connecting member in addition to the moveable node 10b. The adjustment in leverage adjusts how much force is required from a user to compress the coil spring 12 to effect a recline of the backrest 7. For instance, in a "low tension" adjustable position, the spring is compressed a first distance Y1 shown in <figref idref="f0017">Figure 17</figref> and the spring 12 is compressed a second distance Y2 that is greater than the first distance Y1. This compressional distance change causes the spring connecting member 11 to drop further in height when the tilt mechanism 10 is in its high tension position (e.g. a position requiring more compression of a spring to get the backrest to recline to a position as compared to the lower tension position). While the moveable node 10b can permit the amount of force required for reclining of the backrest to be adjustable, it also can avoid any type of pretensioning on the coil spring 12 prior to any reclining motion so that there is no change in the coil spring position or configuration that occurs when the node 10b is moved. Motion of the node 10b results in changing the amount to which the coil spring is compressed due to the change of mechanical leverage that is applied during backrest tilting due to movement of the node 10b.

0025Movement of the node 10b can be effected by an actuator that is connected to a leverage adjustment mechanism. The actuator 6 can be a first actuator 6a that is coupled to an elongated rotatable member 10c that can be operatively connected to the node 10b to drive motion of the node 10b. Alternatively, the actuator 6 can be a second actuator 6b that can be operatively connected to a member so that movement of the actuator can drive motion of the node 10b between low and high tension positions that correspond to being closer or farther from the front side or rear side of plate 15.

0026In some embodiments, the motion of the node 10b can be effected by a node moving mechanism that is coupled to an adjustment actuator 6 for tension adjustment of the tilt mechanism 10 that can occur via mechanical leverage adjustment that is providable by movement of the node 10b. The node motion mechanism for leverage adjustment of the tilt mechanism can include the rotatable member 10c being coupled to an actuator 6 so that rotation of the actuator in a first rotational direction drives rotation of the rotatable member 10c in that first rotational direction and rotation of the actuator in a second rotational direction drives rotation of the rotatable member 10c in the second rotational direction (e.g. counterclockwise when the first rotational direction is clockwise or clockwise when the first rotational direction is counterclockwise). Rotation of the rotatable member 10c can result in the rotational motion of the rotatable member 10c being translated to forward or rearward movement of a node positioning member 10e that is connected to the rotatable member 10c so that rotation of the rotatable member in a first direction drives linear forward motion of the node positioning member 10e and rotation of the rotatable member 10c in the second rotational direction drives rearward motion of the node positioning member 10e. Examples of such connections between the rotatable member 10c and the node positioning member 10e can be a worm gear interconnection, other type of gear connection, or a cam system such as a helix cam system having notches or flats. The interconnection between the rotatable member 10c and the node positioning member 10e can be configured to induce sufficient friction into the tilt mechanism system so that the axis about which the second end 21b of the first tilt member 21 may rotate does not move when the backrest is in a reclined position and/or is tilted away from the upright position towards the reclined position.

0027The node positioning member 10e can be connected to the node 10b so that the forward motion of the node positioning member 10e causes the node 10b to move forwardly along the plate 15 and the rearward motion of the node positioning member 10e causes the node to move rearwardly along the plate 15. In some embodiments, the rotatable member 10c can be connected to the node positioning member 10e via a gear connection mechanism 10d (e.g. a worm gear connection mechanism, etc.) such that rotation of the rotatable member 10c in a first rotational direction drives linear forward motion or rearward motion of the node positioning member 10e and node 10b and rotation of the rotatable member 10c in the opposite second rotational direction causes the node positioning member 10e and node 10b to move linearly in a linear direction opposite to the direction at which these structures move when the rotatable member 10c is rotated in the first rotational direction (e.g. backwardly if the linear motion is forwardly when the rotatable member is rotated in the first rotational direction and forwardly if the linear motion is backwardly when the rotatable member is rotated in the first rotational direction).

0028For instance, the rotatable member 10c can have teeth that mate with a worm gear or worm gear teeth of the node positioning member 10e or a gear connection mechanism 10d for providing a connection between the node positioning member 10e and the rotatable member 10c so that rotation of the rotatable member 10c about a horizontal axis that extends from the left side of the chair 1 to a right side of the chair 1 results in the worm gear teeth being contacted by the rotatable member teeth to drive the linear motion of the node positioning member 10e and node 10b forwardly and rearwardly (e.g. a direction that is perpendicular to the rotational axis of the rotatable member). As another example of a connection between the rotatable member 10c and the node positioning member 10e that can be provided so that rotation of the rotatable member 10c is translated into linear motion (e.g. forward or rearward motion) of the node positioning member 10e, the rotatable member 10c can have teeth that project outwardly and engaged in teeth of the gear connection mechanism 10d that engages to a bottom side or other side of the node positioning member 10e so that rotation of the rotatable member 10c drives linear motion of the node positioning member 10e that is perpendicular to the axis about which the rotatable member 10c rotates (e.g. forward and rearward motion when the axis of rotation of the rotatable member extends horizontally from a left side of the chair to a right side of the chair, etc.) via the intermeshing of the teeth of the rotatable member 10c and the teeth of the gear connection mechanism 10d operatively connected to the node positioning member 10e. In some embodiments, a driving wedge can be positioned between the gear connection mechanism 10d and the node positioning member 10e to push or pull the node positioning member 10e in response to rotation of the rotatable member 10c that is translated to the driving wedge via the gear connection mechanism 10d.

0029In yet other embodiments, the gear connection mechanism 10d can be integrated into the node positioning member 10e such that the node positioning member 10e has threads that mate with threads 10t of the rotatable member 10c to drive the linear motion of the node positioning member 10e. In some embodiments of such a connection, the rotational axis could be defined so that the linear motion of the node positioning member 10e traveled along the rotational axis about which the rotatable member rotates as it moves forwardly or rearwardly instead of a direction that is perpendicular to the rotational axis.

0030For some embodiments, the pitch of the thread 10t and the angle of the driving wedge can be pre-selected to define a number of turns an actuator coupled to the rotatable member 10c needs to be rotated to adjust the position of the node to adjust the recline force a user must exert to recline the backrest. But, if the pitch of the thread is selected solely to reduce the number of turns of an actuator 6 needed for quickly adjusting the tilt mechanism's ability to translate forces to the and from the spring 12, the friction induced could be too low and could result in movement of components of the tilt mechanism out of their selected position during recline, which would dynamically alter the force a user would need to exert to recline the backrest and provide an uncomfortable ride for the user experiencing such a recline motion.

0031For some embodiments, there may be node positioning members on opposite sides of a coil spring 12 (e.g. left and right sides above the coil spring 12 in the housing 10a of the tilt mechanism). For such embodiments, the first and second node positioning members 10e can each be connected to a respective node 10b (e.g. a first node 10b connected to a first node positioning member 10e and a second node 10b connected to a second node positioning member 10e). Each node can be moveable along a plate 15 extending from a first tilt member 21 to be moveable forwardly and rearwardly along that plate for adjusting mechanical leverage applied to the coil spring via recline of the backrest 7. Each node 10b can engage a respective first tilt member 21 (for such embodiments, the second set of first and second tilt members 21 and 23 and spring connecting member 11 can be considered third and fourth tilt members connected between a second leg 7a and a second spring connecting member 11).

0032It should be appreciated that the node 10b is configured so that its position is not adjusted during tilting of a backrest or seat 5. The forward or rearward positional adjustment of the node 10b can be effected by the rotation of rotatable member 10c as discussed herein. During tilting, the node 10b will not move. Friction provided via the connection between the rotatable member 10c and the node positioning member 10e can help ensure that the node 10b stays in its selected position so that the desired portion of leverage is applied for the translation of force to and from the spring 12.

0033In some embodiments, there may be a recline limiter mechanism 30 that is configured to set a maximum amount of recline tilting that the tilt mechanism 10 will permit (e.g. the reclined position can be limited so that the reclined position is at different fully reclined positions from a more reclined position to a less reclined position). The recline limiter mechanism can be considered a tilt limiter mechanism by being configured to be adjusted to different positions to adjust an extent to which a backrest is tiltable, or reclineable. In some embodiments, the recline limiter mechanism can be configured to prevent the backrest 7 from being reclined so that it always stays in the upright position when the recline limiter mechanism is adjusted to a non-tilting position. Such a recline limiter (or tilt limiter) can be connected to an actuator 6 such as the second actuator 6b or a third actuator 6c that may be moveable to adjust a position of stepped recline limiting members 31s that each engage a respective first tilt member 21 at its second end 21b to limit the extent to which that first tilt member 21 is movable for limiting the path of recline for the backrest 7. Each recline limiting member 31s can be considered a tilt limiting member in some embodiments. A position of the recline limiting member 31s can be adjusted via manipulation of an actuator to adjust the position of the recline limiting member.

0034Each stepped recline limiting member 31s can be coupled to a moveable actuator such as a third actuator 6c that is connected to a detent mechanism connecting the third actuator 6c to the stepped recline limiting member 31s so that a motion of the third actuator can move the stepped recline limiting member between multiple different positions. Those positions can include a position corresponding to a non-travel position that prevents the backrest from moving as shown in <figref idref="f0025">Figure 26</figref>, a mid travel position that permits the backrest to travel from an upright position to a mid-reclined position as shown in <figref idref="f0024">Figure 25</figref>, and a full recline position that permits the backrest 7 to move between its upright position and its fully reclined position as shown in <figref idref="f0023">Figure 24</figref>. The detent mechanism 41 can be configured to define these multiple positions and be configured to move between these positions via a connection to the third actuator 6c. The detent mechanism can include a first spring 42 to help facilitate movement of third actuator 6c to provide a desired feel for user motion of the actuator and to hold the actuator in different user selected positions. The detent mechanism can also include a second spring 45 that is moveable to facilitate adjustment of the recline limiter mechanism 30 between multiple different positional settings defined by apertures in which the detent is positionable as a result of motion of the actuator. The second spring 45 can be structured as a leaf spring or other type of spring member that configured to help prevent motion of the detent when the tilt mechanism 10 is in use via recline of the backrest so that the user is unable to exert a force on the tilt mechanism to try and prevent recline of the backrest when the backrest is already reclined. For instance, the spring member of the second spring 45 can be positioned to bend or otherwise resiliently move (e.g. extend or flex) in response to motion of the third actuator 6c when the backrest is reclined and the user's force has exerted a load on the tilt mechanism for recline of the backrest. The biasing force of the second spring 45 can be pre-selected so that this biasing force is unable to force the detent out of its position when the user's recline force acts on the tilt mechanism to recline the backrest so that the detent does not move with the second spring 45, but instead stays in its position, which forces the spring to bend or otherwise extend in response to the motion of the actuator without moving the detent. When the user removes the exerted recline force so that the backrest is returned to its upright position via the spring 12, the second spring 45 of the detent mechanism 41 can be configured to retract back to its biased, unextended position as the biasing force provided by the second spring 45 can now overcome the force acting on the detent mechanism that previously prevented the detent from being moved out of its position. The second spring 45 can be connected to the detent so that this retraction of the second spring 45 results in the detent moving from its initial position to the new position that the user set via motion of the actuator only when the backrest is in the upright position. Providing this type of a delay in adjustment of the detent's position via the second spring 45 can help prevent the user from breaking components of the tilt mechanism 10 by overloading the components when they are in use via the delayed effectuation of the adjustment initiated by the movement of the actuator that can occur when the backrest is already reclined.

0035The recline travel of the backrest can be configured to also synchronously move the seat 5 via the tilt mechanism. For instance, the tilt mechanism 10 can include at least one shaft 10f that extends through one or more slots 10g. The shaft 10f can be connected to the tilt mechanism 10 so that motion of the backrest between the upright and reclined positions causes the shaft 10f to move between front and rear ends of the slot(s) 10g. The seat 5 can be connected to this shaft 10f so that the motion of the shaft within the slot(s) 10g drives motion of the seat (e.g. tilting motion, forward or rearward motion, both tilting and rearward/forward motion, etc.). Each of the slots 10g can have an arcuate shape or other shape to help define the path of travel of the seat to be permitted via tilting of the backrest to help guide the motion of the seat 5 and to help provide friction to the backrest tilting motion to help provide a desired ride, or feel, to the synchronous motion of the seat and backrest that can occur via tilting of the backrest.

0036Legs 7a of the backrest that can extend from a lower portion of the frame of the backrest can be pivotally connected to vertical arms 3i of the tilt mechanism 10 at pivotal connections 3h so that tilting motion of the backrest can also result in a tilting motion of the arms 3i. The arms 3i can extend to the seat or the seat frame of the seat for supporting the seat and to help drive tilting of the seat in response to tilting of the legs 7a via the pivotal connections 3h.

0037For embodiments of the chair that include a backrest 7 having two legs 7a, the tilt mechanism 10 can include two sets of interconnecting structures for operatively connecting the coil spring 12 to each leg 7a of the backrest via a respective set of interconnecting structures. Each leg 7a can be connected to the tilt mechanism 10 via a corresponding set of structures as discussed herein (e.g. each leg 7a can be connected to a respective set of spring connecting member 11, and first and second tilt connecting members 21 and 23 etc.). In other embodiments, it is contemplated that only one leg 7a may be connected to the coil spring 12 via the tilt mechanism 10 and any other legs may only be pivotally connected to other structure to facilitate level, balanced rotation relative to the base that is driven by the coil spring 12 connection to only one of the legs 7a.

0038It should be appreciated that embodiments of the chair may utilize many different feature arrangements to meet different sets of design criteria. For instance, it should be appreciated that some components, features, and/or configurations may be described in connection with only one particular embodiment, but these same components, features, and/or configurations can be applied or used with many other embodiments and should be considered applicable to the other embodiments, unless stated otherwise or unless such a component, feature, and/or configuration is technically impossible to use with the other embodiment. Thus, the components, features, and/or configurations of the various embodiments that can be appreciated from the disclosure provided herein can be combined together in any manner and such combinations are expressly contemplated and disclosed by this statement.

0039For example, the seat 5 may be a unitary structure composed of polymeric material or may be a structure that has many interconnected components, such as a foam member that is positioned between a fabric or leather covering and a rigid plate component or other intermediate structural component positioned above the feet or castors of the chair and below the seat 5 of the chair. For instance, the seat may include a covering that may be a fabric or mesh material that is sewn, adhered or otherwise attached to a relatively rigid polymeric plate or metal plate to enclose a foam member, such as a foam cushion. As yet another example, it should be appreciated that the shape and configuration of the base of the chair may be any of a number of different configurations needed to meet a particular design objective that permit the base to support the seat, chair back, and a user sitting on the seat and leaning on the chair back. As yet another example, the height adjustment mechanism used to actuate seat height adjustment may include only one gas spring or may include another type of lifting mechanism coupled to an actuator that is manipulatable to actuate height adjustment (e.g. a button, lever, or other actuator that is coupled to a component of the height adjustment mechanism via a connector such as a wire or cable or lever such that manipulation of the actuator causes the height adjustment mechanism to move to permit adjustment of the height of the seat). As yet another example, embodiments of the tilt mechanism can be configured to only effect tilting of the backrest such that the seat is independently moveable relative to the backrest and does not tilt or otherwise move synchronously with backrest tilting.

0040As yet another example, each of the armrests 9 can be configured to be affixed in a stationary manner or may be configured to be moveably attached to permit rotational and/or height adjustment of the position of the armrest. The armrests can be attached to the backrest frame, the backrest, the seat frame of the seat, the seat, or the base, and/or a housing or other element positioned under the seat frame 5 that is supported by legs or a pedestal base. As yet another example, the spring 12 can be a metal coil spring 12, an elastomeric spring member, an annular structured elastomeric member, a polymeric member that is resilient and annular in shape (e.g. tubular in shape, a polygonal shaped tube having an inner central channel defined therein, etc.) to function as a spring and move between retracted and extended positions within a channel of a column, or other type of spring member. As yet another example, the composition of the structures of the housing, backrest, armrest, and seat frame can be any of a number of different suitable materials. For example, all of these components may be composed of a polymeric material, or some may be composed of a polymeric material while others are composed of metal or other type of material. Therefore it should be understood that while certain exemplary embodiments of a chair and methods of making and using a chair have been discussed and illustrated herein, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.