Adjustable height wheelchair

A powered wheelchair comprises a frame and an arm assembly that includes an arm that is pivotably coupled to the frame. The arm assembly includes a wheel coupled to the arm. A drive system is coupled to the arm assembly and configured to drive a drive wheel. An arm limiter is pivotably coupled to the suspension and coupled to one or more of the arm assembly and the drive system in an engaged position. The arm limiter is configured to limit movement of the arm assembly in the engaged position.

FIELD OF THE INVENTION

The present invention generally relates to an adjustable height wheelchair and, more particularly, to a powered wheelchair that elevates from a lowered position to a raised position.

BACKGROUND

Wheelchairs are an important means of transportation for a significant portion of society and provide an important degree of independence for those they assist. However, this degree of independence can be limited if the wheelchair is required to traverse obstacles such as, for example, curbs that are commonly present at sidewalks and other paved surface interfaces, and door thresholds. Accordingly, powered wheelchairs have been the subject of increasing development efforts to provide handicapped and disabled persons with independent mobility to assist them in leading active lives.

To aid in climbing curbs, some power wheelchairs typically have a pair of forward extending anti-tip assemblies that are rotatably coupled to the wheelchair frame. The arms of the anti-tip assemblies are rotatably coupled to the wheelchair frame such that when the wheelchair encounters a curb, the anti-tip assemblies will pivot upwardly to thereby allow the wheelchair to traverse the curb. Some power wheelchairs also have elevatable seats that permit the occupant to move at “eye-level” with persons walking with them. However, wheelchairs operating with seats at elevated positions are susceptible to instability under certain conditions, and anti-tip assemblies, while beneficial for climbing obstacles such as curbs, may contribute to the instability when the wheelchair is operating on other than flat, level ground.

BRIEF SUMMARY OF THE INVENTION

In one embodiment there is a powered wheelchair comprising a frame; an arm assembly including an arm that is pivotably coupled to the frame, the arm assembly including a wheel coupled to the arm; a suspension coupled to the frame and to the arm assembly; a drive system coupled to the arm assembly and configured to drive a drive wheel; and an arm limiter pivotably coupled to the suspension and coupled to one or more of the arm assembly and the drive system in an engaged position, the arm limiter being configured to limit movement of the arm assembly in the engaged position. In one embodiment, the arm limiter includes a latch arm, the latch arm having a notch for engaging a catch extending from the one or more of the arm assembly and the drive system in the engaged position. In one embodiment, the latch arm is bent generally in the shape of a question mark. In one embodiment, the arm limiter includes a spring coupled between the latch arm and the suspension, the spring being configured to bias the latch arm toward the engaged position. In one embodiment, the latch arm includes a free distal end configured to engage with a projection extending from a lift mechanism of the powered wheelchair.

In a further embodiment, the powered wheelchair includes an expandable traction member coupled to one or more of the arm assembly and the drive system and to the frame. In one embodiment, the expandable traction member is configured to bias the arm assembly upwardly relative to a ground surface. In one embodiment, the arm limiter is pivotably coupled to the suspension proximate where the expandable traction member is coupled to the frame.

In a further embodiment, the powered wheelchair includes a lift mechanism supported by the frame; and a seat supported by the lift mechanism, the lift mechanism configured to move the seat between a lowered position and a raised position. In one embodiment, the lift mechanism includes a projection configured to engage the arm limiter in the lowered position and release the arm limiter in the raised position and allow the arm limiter to transition to the engaged position. In one embodiment, the suspension includes a lever pivotably coupled to the frame and a compression spring coupled between the frame and the lever, the arm limiter being pivotably coupled to the lever. In one embodiment, the arm limiter is prevented from transitioning to the engaged position depending on the position of the arm assembly. In one embodiment, the drive system includes an electric motor and a gear box. In one embodiment, the drive system is rigidly coupled to the arm assembly and indirectly coupled to the frame by the arm assembly. In one embodiment, the arm assembly includes a catch, and the arm limiter is coupled to the catch in the engaged position. In one embodiment, the arm limiter includes a sensor, the drive system being configured to drive the drive wheel at a reduced speed when the sensor detects that the arm limiter is in the engaged position.

In one embodiment, there is a a powered wheelchair comprising: a frame; a lift mechanism supported by the frame; a seat supported by the lift mechanism, the lift mechanism configured to move the seat between a lowered position and a raised position; a pair of drive wheels; at least one drive coupled to the frame and configured to apply a torque to at least one of the drive wheels; an arm assembly including an arm that is pivotably coupled to the frame and a wheel coupled to the arm, the arm configured to be in a first position relative to the frame when the powered wheelchair is operating on flat ground and to be rotatable from that first position, the arm assembly having a suspension coupled to the frame; an arm limiter configured to inhibit motion of the arm when the seat is in the raised position, the arm limiter having a first configuration in which the arm is rotatable from the first position through a first range of rotation, and a second configuration in which the arm is rotatable from the first position only through a second range of rotation that is smaller than the first range of rotation, the arm limiter coupled to the suspension and configured to engage the arm assembly in the second configuration; and a trigger mounted to the lift mechanism and coupled with the arm limiter such that as the seat is moved between the lowered and raised positions, the trigger causes the arm limiter to transition between the first and second configurations, wherein the arm limiter is prevented from transitioning into the second configuration when the arm is rotationally different from the first position relative to the frame by more than a predetermined amount.

In one embodiment, the trigger is configured to urge the arm limiter toward the first configuration as the lift mechanism moves the seat from the raised position to the lowered position. In one embodiment, the predetermined amount is greater than or equal to 4 degrees. In one embodiment, the trigger includes a projection projecting laterally from a side of the lift mechanism. In one embodiment, the suspension comprises a first suspension component having a first range of travel and a second suspension component having a second range of travel that is less than the first range of travel and wherein the second suspension component is configured to move through the second range of travel during operation of the powered wheelchair only when the arm limiter is in the second position. In one embodiment, the first suspension component is configured to compress an amount that is less than the first range of travel when the arm limiter is in the second position. In one embodiment, the second suspension component is configured to compress through the entire second range of travel when the arm limiter is in the second position.

In one embodiment, there is a powered wheelchair comprising: a frame; a lift mechanism supported by the frame; a seat supported by the lift mechanism, the lift mechanism configured to move the seat between a lowered position and a raised position; a pair of drive wheels; at least one drive coupled to the frame and configured to apply a torque to at least one of the drive wheels; an arm limiter; an arm assembly including an arm that is pivotably coupled to the frame and a wheel coupled to the arm, the arm configured to be in a first position relative to the frame when the powered wheelchair is operating on flat ground and to be rotatable from that first position, the arm assembly having a suspension configured to control motion of the arm assembly relative to the frame depending upon a configuration of an arm limiter, the arm limiter configured to inhibit motion of the arm when the lift mechanism is in the raised position, the arm limiter having a first configuration in which the arm assembly is rotatable from the first position through a first range of rotation, and a second configuration in which the arm is rotatable from the first position only through a second range of rotation that is smaller than the first range of rotation, the arm limiter coupled to the suspension and configured to engage the arm assembly in the second configuration; and a trigger mounted to the lift mechanism and coupled with the arm limiter such that as the seat is moved between the lowered and raised positions, the trigger causes the arm limiter to transition between the first and second configurations, wherein the arm limiter is prevented from transitioning into the second configuration when the arm is rotationally different from the first position relative to the frame by more than a predetermined amount.

In one embodiment, the suspension comprises a first suspension component having a first range of travel and a second suspension component having a second range of travel wherein the first suspension component is compressible through the first range of travel when the arm limiter is not in the engaged position and the second suspension component is compressible through the second range of travel when the arm limiter is in the engaged position. In one embodiment, the suspension is a suspension means for controlling motion of the arm assembly relative to the frame depending upon a configuration of an arm limiter.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings in detail, wherein like reference numerals indicate like elements throughout, there is shown inFIGS. 1A-7an adjustable height wheelchair, generally designated10, an exemplary embodiment of the present invention. Various embodiments of the adjustable height wheelchair are described in further detail below in reference to the exemplary embodiment shown in the figures. Additional examples of powered wheelchairs having lift and suspension mechanisms are disclosed in U.S. Patent Application Publication No. 2015/0196441 and U.S. Pat. No. 8,408,343 which are hereby incorporated by reference in their entirety.

Referring toFIGS. 1A-3C, the adjustable height wheelchair10(also referred to as wheelchair10) may be configured to elevate a seated occupant and operate the wheelchair10in a safe, stable condition dependent on the occupant's position, ground surface features, and/or one more or more wheelchair operational parameters. The wheelchair10may be configured to elevate a chair or seat12between a conventional lowered position (e.g.,FIGS. 1A-1C) and raised or elevated positions (e.g.,FIGS. 2A-2Cillustrate a partially elevated position andFIGS. 3A-3Cillustrate a fully elevated position). Providing an adjustable height wheelchair10may allow an occupant to operate the wheelchair10with the seat12in the raised position, which in some circumstances can be at a conversational or eye-to-eye level height with others who are standing or walking along with the wheelchair10. In one embodiment, the wheelchair10raises the seat12more than six (6) inches above its most lowered state. In one embodiment, the wheelchair10raises the seat12seven (7) inches above its most lowered state. In one embodiment, the wheelchair10raises the seat12eight (8) inches above its most lowered state. In one embodiment, the wheelchair10raises the seat12nine (9) inches above its most lowered state. In one embodiment, the wheelchair10raises the seat12ten (10) inches above its most lowered state. In one embodiment, the wheelchair10raises the seat12more than 10 inches.

The wheelchair10may be a powered wheelchair. In some embodiments, wheelchair10may be configured to selectively limit certain operational aspects when, for example, the wheelchair10is in the process of traversing an obstacle, is on un-level ground, and/or when the seat12is raised. Likewise, the wheelchair10may prevent the raising of the seat12when the wheelchair10is climbing an obstacle or is on unlevel ground. An “obstacle”14as the term is used herein may include any relatively raised or lowered structure on the ground surface G that the wheel must ascend or descend to cross over (seeFIGS. 5A-6B). Operating a wheelchair when the seat is in the elevated position can create instability, especially when climbing curbs or transitioning to a descent when appropriate safety features are not deployed. For instance, when the seat12is in the fully raised position, the center of gravity of the occupied wheelchair is also elevated and/or shifted forward or rearward (depending, for example, on the lift mechanism associated with the chair). The risk of tipping can increase on an incline and overall wheelchair stability can be compromised, especially when traversing or attempting to traverse an obstacle.

The wheelchair10may be configured with supplemental stability features when the seat12is in the elevated position. The supplemental stability configuration may permit wheelchair10to operate at increase travelling speeds when the chair is elevated as compared to elevated height wheelchairs that are not so configured. Increased traveling speeds may include walking, jogging, or running speeds. Conversational height as used herein refers to when the occupant is elevated to a level above the ground surface G (seeFIGS. 5A-6B) to make communication with others (e.g., average height adult males or females) standing or walking next to the wheelchair10easier. For example, conversational height could place the user “eye-level” with someone standing next to the wheelchair10.

With continued reference toFIGS. 1A-1C, the powered wheelchair10may include a frame16(seeFIG. 7), a pair of drive wheels18coupled to the frame16and driven by at least one drive system20(seeFIG. 4A). A pair of front anti-tip arm assemblies22may extend from the frame16in a forward direction F relative to the drive wheels18. A pair of rear anti-tip arm assemblies24may extend from the frame16in a rearward direction R that is opposite to the forward direction F. As used herein the forward-rearward direction F-R may refer the horizontal direction when the wheelchair is operating on flat, level ground. In accordance with the illustrated embodiment, the wheelchair10may be a mid-wheel drive power wheelchair and include front wheels26and rear wheels28disposed in the forward and rearward directions F and R relative to the drive wheels18, respectively. The drive system20may include an electric motor and gear box configured to cause the drive wheels18to rotate about the drive wheel axis A1to advance the wheelchair10along the surface G. The front wheel26may be rotatable about the front wheel axis A2and the rear wheel28may be rotatable about the rear wheel axis A3. The present disclosure, however, is not limited to mid-wheel powered wheel chairs and may include any number of wheels.

Referring toFIGS. 3A-3C, the powered wheelchair10may also include a lift mechanism30mounted to the frame16with the seat12supported by the lift mechanism30. The lift mechanism30may be configured to, in response to inputs an occupant applies to an input device for example, move the seat12between a lowered position (FIGS. 1A-1C) and a raised position (FIGS. 3A-3C) generally along a vertical direction V (seeFIG. 1A) that is substantially perpendicular the forward and rearward directions F and R. The lift mechanism30may include a telescopic pillar mechanism as shown. The lift mechanism30may include a screw type actuator. In one embodiment, the lift mechanism30includes two or more housing segments (e.g.,30a,30b,30c) that are telescopically coupled to one another to cover the actuator. In one embodiment, the housing segments30a,30b,30care arranged such that the top segment30cslides over the middle segment30bwhich slides over the bottom segment30a. The housing segments (e.g.,30a,30b,30c) may have a non-circular cross sectional shape to prevent the chair12from rotating relative to the frame16. In one embodiment, the housing segments (e.g.,30a,30b,30c) are generally rectangular in cross sectional shape. In other embodiments, the housing segments (e.g.,30a,30b,30c) are generally triangular or oval in cross sectional shape. In other embodiments, the housing segments (e.g.,30a,30b,30c) are generally circular in cross sectional shape to allow the chair12to rotate relative to the frame16.

In other embodiments, another type of lift mechanism may be employed such as a scissor lift. Further, the wheelchair10can be configured to move the seat12into the raised position and tilt the seat base and seat back relative to each other in the raised position. In an embodiment, the wheelchair10can include a lift and tilt mechanism, such as the lift and tilt mechanism disclosed in U.S. Patent App. Pub. No. 2014/0262566, entitled “Lift Mechanism And Tilt Mechanism For A Power Wheelchair,” incorporated by reference herein in its entirety.

The lift mechanism30may include a trigger30d. The trigger30dmay include a block extending laterally from the lift mechanism30. In one embodiment, the trigger30dextends from the outermost top segment30c. In one embodiment, a trigger30dextends from each lateral side of the lift mechanism30in direction generally perpendicular to the forward F and rearward R directions (seeFIG. 1A). The trigger30dmay be configured to engage and release an arm limiter as discussed in further detail below.

Turning toFIGS. 4A and 4B, as noted above, the wheelchair10includes a pair of front anti-tip arm assemblies22. For ease of illustration only one anti-tip arm assembly22is shown and described below. The other anti-tip assembly22in the pair preferably has the same structure but oriented on the opposite side of the wheelchair10. The anti-tip arm assembly22may also be referred to in this disclosure as an arm assembly22. In one embodiment, the arm assembly22is rotatable coupled to frame16. For example, the arm assembly22may include an arm member32rotatably coupled to the frame16. A front wheel26may also be coupled to the arm assembly (e.g., the wheel26may be coupled to the arm member32). The arm member32may include an arm extension32a. The arm extension32amay extend downwardly from the arm member32. In one embodiment, the arm extension32ais hook shaped (seeFIG. 7). In one embodiment, the arm extension32ais rigidly connected to the arm member32. The arm extension32amay be pivotably coupled to the frame16. In one embodiment, arm assembly22may be directly coupled to frame16only via arm extension32a. In one embodiment, the arm extension32ais pivotably coupled to the frame16about axis A4. In one embodiment, axis A4is generally parallel with axis A1(seeFIG. 1A). The arm member32and arm extension32acan be formed of multiple components that are connected together with fasteners or welds, or pivotally attached together, without limitation. In other embodiments, the arm member32and arm extension32acan be a monolithic structure, such as a cast or extruded material.

Referring toFIGS. 5A-6B, the front wheel26is coupled to the distal end of the arm assembly22and is rotatable about the front wheel axis A2. As illustrated, the front wheel26is in contact with ground or surface G during normal operation. The front wheel26may be part of a caster assembly. The caster assembly rotatably couples the front wheel26to the arm member22such that front wheel26is rotatable about an axis that is generally perpendicular to the ground surface G and perpendicular the wheel axis A2. In some embodiments, the front wheel26can be an anti-tip wheel that is raised or otherwise spaced from the ground or surface G during normal operation in a configuration that does not include a caster. The term “anti-tip” wheel as used herein encompasses caster wheel assemblies (that may include for example, front wheel26) and anti-tip wheels that are raisable during normal operation and encompasses wheels in the front and the rear of the wheelchair10. In some embodiments, the raisable anti-tip wheels can have a first or rest position when the wheelchair10is operating on flat, level ground G.

The arm assembly22may be coupled to the frame16and configured to move the wheel26relative to the frame16upon encountering an obstacle14. The arm assembly22may be pivotably coupled the frame16such that the arm assembly22and wheel axis A2pivot about the pivot axis A4. It should be appreciated, however, that the arm assemblies22can be coupled to the frame16such that the arm member22and wheel axis A2translate relative to the frame16.

Referring toFIGS. 4A and 4B, the arm assembly22may be coupled to the drive system20. The drive system20may be rigidly coupled to the arm assembly22and indirectly coupled to the frame16by, for example, the arm assembly22. In one embodiment, the drive system20and the arm assembly22are configured to pivot relative to the frame16together about a common axis A4. Coupling the drive system20and the arm assembly to one another may allow for a simplified suspension system such as those described in further detail below. In one embodiment, the arm assembly22is coupled to the drive system20at a plurality of points (e.g., P1, P2, P3) around the drive axis A1. In one embodiment, the arm assembly22is coupled to the drive system20at the plurality of points (e.g., P1, P2, P3) via a fastener such as a bolt. In one embodiment, a tie bar34extends between two (or at least two) of the points (e.g., P1and P2). Because the tie bar34may be rigidly coupled to both the arm assembly22and the drive system20, the tie bar34in some embodiments may be considered to be part of the arm assembly22or part of the drive system20. In other embodiments, the drive system20may be moveably connected to the arm assembly22, at least initially, to allow the drive system20to rotate relative to the frame16a predetermined amount before moving simultaneously with the arm assembly22.

Referring toFIG. 7, a traction member36may be coupled between one or more of the arm assembly22and the drive system20and to the frame16. For example, traction member36may be coupled between the arm assembly22and the frame16, or traction member36may be coupled between the drive system20and to the frame16. The traction member36may include a biasing member such as a tension spring or in some embodiments, a compression spring. In one embodiment, the traction member36is provided to urge the drive wheel18downward so that the drive wheel18maintains contact with the ground surface G. In one embodiment, the traction member36is coupled to a bracket34aextending from the tie bar34at one end and to an extension arm16aof the frame16at another end.

Referring toFIGS. 4A-4B, the wheelchair may include one or more arm limiters46configured to selectively engage one or more of the arm assemblies22so as to inhibit relative motion between the one or more arm assembly assemblies22and frame16. In one embodiment, an arm limiter46is configured to automatically engage one or more of the arm assemblies upon the occurrence of a predefined operational condition of in certain instances during operation of the wheelchair10(e.g., when the wheelchair is in an elevated condition). The arm limiter46may be coupled to the frame16. In some embodiments, the arm limiter46is indirectly coupled to the frame16by a suspension as discussed below. When the wheelchair10is in an elevated position and the center of gravity is raised, the arm assembly22without arm limiter46may not provide sufficient support and result in instability or tipping of the chair. Preventing relative motion between the arm assembly22and the frame16can limit certain operation conditions of the wheelchair10in order to improve stability and occupant safety. The arm limiter46may transition between a first or disengaged configuration and a second or engaged configuration where operational movement of the arm assembly22is limited. Further, operation of arm limiter46may be limited, inhibited, impaired or delayed when the wheelchair is traversing an obstacle14. For instance, the arm limiter46may not transition into an engaged configuration if the arm assembly22is engaged in attempting to traverse an obstacle14, as will be further discussed below.

Referring toFIGS. 4A and 4B, the wheelchair10may include an obstacle suspension38. The obstacle suspension38may include a biasing member such as a compression spring40. The suspension38may be coupled to the arm limiter46(e.g., at one end of the obstacle suspension38) and the frame16(e.g., at another end of the obstacle suspension38) to couple the arm limiter46to the frame16. In one embodiment, the suspension38is considered part of the arm limiter46. The suspension38may be pivotably coupled to frame16—about axis A5, for example. In one embodiment, obstacle suspension38may include a lever42pivotably coupled to the frame16about axis A5. In one embodiment, axis A5is generally parallel with axis A4. In one embodiment, axis A5is proximate axis A4. In one embodiment, axis A5is positioned between axis A4and the wheel26. The lever42may be coupled to the frame16by a fastener such as a bolt. A fastener44, such as a bolt, may be coupled to the frame16, extend through the compression spring40and be coupled to the lever42. In one embodiment, the suspension38is configured to resist the pivoting of arm assembly32relative to the frame. For example, the suspension38may be configured to resist an upward movement (in the vertical direction V, seeFIG. 1A) of wheel26and/or an upward impact on wheel26.

In one embodiment, the arm limiter46is configured to limit movement of the arm assembly22relative to the frame in an engaged position. The engaged position may include a configuration in which the arm limiter46may be coupled to the suspension38and coupled to one or more of the arm assembly22and the drive system20. In one embodiment, the arm limiter46is configured to engage the tie bar34in the engaged position. In one embodiment, the arm limiter46is configured to engage a catch34bextending from the tie bar34in the engaged position. The arm limiter46may be pivotably coupled to the obstacle suspension38. In one embodiment, the arm limiter46is pivotably coupled to the obstacle suspension38about axis A6. In one embodiment, axis A6is generally parallel to axis A4. In one embodiment, arm limiter46is coupled to the obstacle suspension38proximate where the traction member36is coupled to the frame16.

The arm limiter46may be in the form of a latch arm46. The arm limiter46may have a first notch46aconfigured to engage the catch34bextending from the tie bar34in the engaged position. The arm limiter46may include a second notch46bconfigured to engage the catch34bextending from the tie bar34in the disengaged position. The arm limiter46may be bent generally in the shape of a question mark. In one embodiment, arm limited46is biased to pivot toward obstacle suspension38—for example, into a position that reduce a range of travel of obstacle suspension38as described herein. In one embodiment, a biasing member such as a tension spring48is coupled between the arm limiter46and the suspension38. The spring48being configured to bias the arm limiter46toward the engaged position. The arm limiter46may be shaped such that the first and second notches46a,46bare within a pocket between the spring48and arm limiter46. The arm limiter46may have a distal end46cthat is configured to engage with the trigger30dof the lift mechanism. In one embodiment, the distal end46cof the latch arm46is a free end. The distal end46cmay be shaped to be generally parallel with axis A4.

Referring toFIGS. 5A and 5B, the arm limiter46is shown in the disengaged position. On level ground G such as shown inFIG. 5A, with the seat in the lowered position, the trigger30dmay engage the arm limiter46(e.g., at the distal end of the arm limiter46) and space the arm limiter46from the catch34b. When the wheel26encounters an obstacle14such as shown inFIG. 5B, the arm assembly22is pivoted relative to frame16an angle β1until the catch34bengages a second notch46bof the arm limiter pivoting the arm limiter46relative to the suspension38. The arm assembly22may pivot relative to the frame (e.g., about axis A4) until the spring40(seeFIG. 4B) of the suspension38is fully compressed. In other embodiments, the vertical pivot limit of the arm assembly22is dictated by a limit of the traction member36. As illustrated inFIG. 5B, the arm limiter46is prevented from transitioning to the engaged position depending on the position of the arm assembly22.

Referring toFIGS. 6A and 6B, the arm limiter46is shown in the engaged position. On level ground G such as shown inFIG. 6A, with the seat in the elevated position, the trigger30dmay be disengaged from the distal end of the arm limiter46such that the biasing member48pivots the arm limiter46relative to arm assembly22until the first notch46aof the arm limiter46is engaged with the catch34b. When the wheel26encounters an obstacle14such as shown inFIG. 5B, the arm assembly22is pivoted relative to frame16an angle β2until the spring40of the suspension38is fully compressed. In one embodiment, lowering the seat12causes the trigger30dto engage the distal end of the arm limiter46, releasing the arm limiter46from the catch34b. In one embodiment wheelchair10includes a sensor50for detecting when the arm limiter46is in the engaged position. The sensor50may be a contact sensor, an electromagnetic sensor and/or a proximity sensor. The sensor50may be positioned on or proximate to catch34b. In one embodiment, the arm limiter46includes a sensor50proximate the first notch46a. Such a sensor50may indicate to a controller that the arm limiter46is in the engaged position. In one embodiment, a controller receives a signal from sensor50that indicates arm limiter46is in the engaged position and in response to the signal generates a control signal that implements a selected and select a desired operation of the wheelchair10as discussed in further detail below.

Referring toFIGS. 5A-6B, the wheelchair10may have different operational modes, such as a standard mode and one or more elevated motion modes. In some embodiments, a control system includes a controller configured to operate the wheelchair10in the different operational modes, an input device in electronic communication with the controller, and one or more sensors in electronic communication with the controller. The controller may be responsive to inputs from the input device and one or more of the sensors in order to cause the wheelchair10to operate at least in (i) a standard mode when the seat12is in the lowered position such that the wheelchair10is moveable along the surface G in accordance with standard drive parameters (that is, conventional parameters that are not limited for elevated seat operation), and (ii) one or more elevated motion modes whereby the seat12is in the raised position and drive parameters are limited to some extent. The elevated motion modes may include A) a first or normal elevated motion mode where the wheelchair is capable operating according to a first set of limited drive parameters, and B) a second elevated motion mode (sometimes referred to as an elevated-inhibited mode) whereby the wheelchair10is capable of operating according to a second set of limited drive parameters that have limits that are typically less than upper limits of the first set of limited drive parameters. The phrase “drive parameters” as used herein (whether in standard or elevated modes) may include a speed (miles/hr), acceleration, and deceleration of the wheelchair10. In some embodiments, the drive parameters include directional components, such as forward speed, reverse speed, and turn speed, forward acceleration, forward deceleration, reverse acceleration, and reverse deceleration. For brevity and ease of illustration, the standard and elevated modes below are described with reference to the speed of the wheelchair10. However, it should be appreciated that the ranges and limits discussed below with respect to speed are applicable to the other drive parameters such as turn speed, acceleration, and deceleration described above.

In one embodiment, the standard mode may be when the seat12is in the lowered position such that the wheelchair is moveable along the surface G at typical wheelchair speeds. The first elevated motion mode can be when the wheelchair10is capable of moving at a first speed range, up to a maximum raised-seat drive speed, which is less than the typical wheelchair speeds. The second elevated motion mode (or an elevated-inhibited mode) is when the wheelchair10is capable of moving at a second elevated mode speed range, up to a maximum raised-inhibited drive speed that is less than the upper limit of the first speed range.

In the standard mode the wheelchair10may move at a standard or lowered-seat drive speed range that is typical of conventional wheelchairs, such from 0.0 mph to about 10.0 mph. Accordingly, it should be appreciated that the fully lowered-seat drive speed can have an upper limit that is anywhere in the conventional range from a practical minimum (or at rest at 0 mph) to, for example, 10.0 mph as indicated. Furthermore, it should be appreciated that when the wheelchair10is operating in the standard mode, the wheelchair10can be configured to move at any speed as desired and is not limited to a speed that is between the practical minimum and 10.0 mph. The powered wheelchair10would typically be in the standard mode (that is, with the seat in the fully-lowered position) when the wheelchair10is traversing obstacle14such as a curb. The term “standard mode” includes a mode that has no speed restrictions by the controller that are related to seat position.

When in the elevated motion modes, the wheelchair10may be configured to move at a speed that has a limit that is less than the standard mode drive speed upper limit. In the elevated motion modes, the wheelchair10preferably is capable of moving at a walking speed (or perhaps faster) while seat12is in the raised position such that the occupant is at the conversational height with a person walking next the powered wheelchair. In an exemplary embodiment, when in the normal elevated motion mode, the first speed range is from a practical minimum to 5.0 mph, preferably from the practical minimum to 3.75 mph. That is, the wheelchair10can be configured to move at a maximum raised-seat drive speed that is no more than 5.0 mph, preferably no more than 3.75 mph. In one embodiment, the wheelchair10is configured to move at a maximum raised-seat drive speed that is no more than 3.5. It should be appreciated that the raised-seat drive speed can have an upper limit that is anywhere from a first speed range of the practical minimum to 5.0 mph. Furthermore, when the wheelchair10is operating in the normal elevated motion mode, there may be circumstances in which the upper limit may be set higher than 5.0 mph. The term “practical minimum” speed as used herein means that the lower limit of the range is chosen according to the parameters understood by persons familiar with wheelchair structure and function, and may be close to zero mph under some conditions.

In an instance in which wheelchair10is operating in the elevated motion mode, and at least one safety criteria is not met, the controller may cause the wheelchair10to operate in some mode other than the first, normal elevated motion mode. For example, the controller may cause the wheelchair10to operate in the second elevated motion mode or elevated inhibited mode at least until all of the safety criteria are met. For example, in some embodiments, if the seat12is in the raised position and one of the safety criteria is not met, the controller may allow the wheelchair10to move within the second, elevated-inhibited speed range, up to the reduced maximum raised-inhibited speed that is less then maximum raised-seat drive speed. The maximum raised-inhibited drive speed can be a speed that is no more than 3.0 mph, preferably no more than 1.5 mph. In one embodiment, the maximum raised-inhibited drive speed can be a speed that is no more than 1.25 mph. It should be appreciated, however, that the raised-inhibited drive speed can have any upper limit as desired so long as it is less than an upper limit of the first, normal speed range.

The maximum speed of the wheelchair may be reduced when one or more of the arm limiters is not engaged in the elevated position. In one embodiment, the maximum standard or lowered-seat drive speed is approximately 10 mph, the maximum elevated motion mode speed with both arm limiters engaged is approximately 3.5 mph, and the maximum elevated motion mode speed with one or more arm limiters not engages is approximately 1.25 mph.

Accordingly, in order for the wheelchair10to operate in the elevated motion modes, certain safety criteria should be satisfied as will be discussed further below. One or more senors may detect information indicative of when the wheelchair10is in a position to safely operate in the elevated motion modes. Those sensors may include contact sensors, electromagnetic sensor and/or proximity sensors. If the sensors detect a condition that indicates that it is not safe to operate the wheelchair10in the elevated motion mode, the controller may operate the wheelchair10in some other mode such as the elevated inhibited mode or standard mode (that is, by requiring the seat12to be in the lowermost position). In certain instances, for example, the wheelchair10will not operate in the elevated motion modes, i.e., the seat12will not move into the raised position if the seat12is initially in the lowered position and the wheelchair10is ascending an obstacle or descending down an incline.

Arm assembly22may have a variety of different ranges of motion depending on the state of wheelchair10. The range of rotation as used herein refers to rotation of the arm assembly22to a position that is different than a first position (e.g., the position illustrated inFIG. 5A). When the arm assembly22is in the first position, such that the wheelchair10is operating on flat, level ground G, a first, fixed reference line L intersects the pivot axis A4and the front wheel axis A2. The line L defines an angle α from the ground surface G in the first position. In one embodiment, the angle α is approximately 5 degrees. In other embodiments, the angle α may be approximately 4 degrees, 3 degrees, 2 degrees, or 1 degree. Referring toFIG. 5B, the arm assembly22may have a first range of motion relative to frame16in the disengaged position such that reference line L is movable up to an angle β1relative to the ground surface G. In one embodiment, the angle β1is approximately 15 degrees. In other embodiment, the angle β1 may be approximately 14 degrees, 13 degrees, 12 degrees, 11 degrees, 10 degrees or 9 degrees. Referring toFIG. 6B, the arm assembly22may have a second range of motion relative to frame16in the engaged position such that reference line L is movable up to an angle β2relative to the ground surface G, the angle β2being less than angle β1. In one embodiment, the angle β2is approximately 10 degrees. In other embodiments, the angle β2, may be approximately 14 degrees, 13 degrees, 12 degrees, 11 degrees, 10 degrees, 9 degrees, 8 degrees, 7 degrees or 6 degrees. In one embodiment, the angle β1is approximately ⅔rds of angle β2. In one embodiment, the angle β1is less than approximately ⅔rds of angle β2. In one embodiment, angle β2is approximately ⅔ the value of angle β1In one embodiment, the bottom of the front wheel26lifts no more than approximately 1.5″ off ground Gin the engaged position. In one embodiment, the bottom of the front wheel26lifts no more than approximately 1.25″ off ground G in the engaged position. In one embodiment, the bottom of the front wheel26lifts no more than approximately 1″ off ground G in the engaged position. In one embodiment, the bottom of the front wheel26lifts no more than approximately 0.75″ off ground G in the engaged position.

The arm limiter46may be disengaged when the wheelchair10is operating in the standard motion mode, i.e., when the seat12is in the lowered position. When the controller receives an input from the input device to operate the wheelchair10in the elevated motion mode, the controller may causes the arm limiter to transition into the second or engaged configuration. However, if certain conditions are not met, the arm limiter46may be inhibited from moving into the engaged position. For example, the arm limiter46may be able to move into the engaged position only when the front wheel26and drive wheel18are on flat, level ground G (or substantial flat, level ground). If the front wheel26is on a surface that is raised relative to the drive wheel18and to ground surface G such that the arm assembly22is pivoted vertically as shown inFIG. 5B, then the arm limiter46is physically blocked from moving into the engaged position (e.g., the catch34bhas already passed the first notch46a. If the front wheel26then returns to the ground plane G, biasing or tension spring48may cause the arm limiter46to move to the engaged position. If the lift mechanism30is lowered while the front wheel26is on a raised surface relative to ground plane G, trigger30dmay cause the arm limiter46to rotate about its axis A6and allow arm22to rotate beyond the raised angle limit without causing undue stress or damage to components of the wheelchair10.

In one embodiment, wheelchair10includes a suspension means for controlling motion of arm assembly22relative to frame16depending upon a configuration of arm limiter46(e.g., depending upon whether the arm limiter is in the engaged position or not in the engaged position). In one embodiment, the suspension means includes a first suspension component such as traction member36and/or a second suspension component such as obstacle suspension38(illustrated for example inFIG. 4A). In one embodiment, the first suspension component has a first range of travel and the second suspension component has a second range of travel that is less than the first range of travel. The suspension may be configured such that the first range of travel is only achieved (e.g., when the first suspension component is fully compressed) when the arm limiter is not in the engaged position. The suspension means may also be configured such that the second range of travel is only achieved (e.g., when the second suspension component is fully compressed) when the arm limiter is in the engaged position. In one embodiment, arm limiter22, the second suspension component (e.g., obstacle suspension38) and the first suspension component (e.g., traction member36) are coupled (e.g., each being rotatably coupled) to wheelchair10at a common axis (e.g., axis A6illustrated, for example, inFIG. 4A).

In one embodiment, the adjustable height wheelchair10includes one or more computers (e.g., a controller) having one or more processors and memory (e.g., one or more nonvolatile storage devices). In some embodiments, memory or computer readable storage medium of memory stores programs, modules and data structures, or a subset thereof for a processor to control and run the various systems and methods disclosed herein. In one embodiment, a non-transitory computer readable storage medium having stored thereon computer-executable instructions which, when executed by a processor, perform one or more of the methods disclosed herein.

It will be appreciated by those skilled in the art that changes could be made to the exemplary embodiments shown and described above without departing from the broad inventive concepts thereof. It is understood, therefore, that this invention is not limited to the exemplary embodiments shown and described, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the claims. For example, specific features of the exemplary embodiments may or may not be part of the claimed invention and various features of the disclosed embodiments may be combined. Unless specifically set forth herein, the terms “a,” “an” and “the” are not limited to one element but instead should be read as meaning “at least one.”

Further, to the extent that the methods of the present invention do not rely on the particular order of steps set forth herein, the particular order of the steps should not be construed as limitation on the claims. Any claims directed to the methods of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the steps may be varied and still remain within the spirit and scope of the present invention.