Patent Description:
According to one embodiment of the invention, a mobility vehicle comprises a frame, a first pivot arm coupled to the frame and coupled to a drive wheel, a second pivot arm coupled to the frame and coupled to a ground engaging caster wheel, and a suspension assembly coupled to the frame. The suspension assembly may include a first spring assembly, disposed about a first spring axis, and coupled to the first pivot arm; and a second spring assembly, disposed about a second spring axis, and coupled to the second pivot arm. The first spring axis and the second spring axis may be disposed relative to each other at an angle of no greater than about <NUM> degrees when the mobility vehicle is operating on horizontal ground.

The first pivot arm may include an anti-tip element. The first pivot arm is configured and dimensioned to cause the anti-tip element to move relative to a drive wheel axis when the first pivot arm pivots. The first pivot arm is coupled to the frame at a first rod extending from a left side of the frame to a right side of the frame and the second pivot arm is coupled to the frame at a second rod extending from the left side of the frame to the right side of the frame, each of the first rod and second rod fixedly attached to the frame in a configuration to stiffen the frame. The first axis may be closer to horizontal than the second spring axis.

The mobility vehicle includes a stiffening bridge disposed from the first rod to the second rod. The stiffening bridge may be an outermost point of the frame. The second pivot arm may include a first substantially linear arm segment extending at least from a point at which the second pivot arm may be coupled to the frame through a point at which the second pivot arm may be coupled to the second spring assembly. The second pivot arm may include a second arm segment extending from the linear arm segment to at least a caster stem axis. The second spring axis may be approximately normal to the first substantially linear segment when the mobility vehicle is on substantially horizontal ground. A horizontal projection of a first line may pass through a) a point at which the first spring assembly is coupled to the frame and b) a point at which the second spring assembly is coupled to the frame may intersect a horizontal projection of a second line passing through c) a point at which the first spring assembly is coupled to the first pivot arm and d) a point at which the second spring assembly is coupled to the second pivot arm.

The intersection of the horizontal projection of the first line and the horizontal projection of the second line may be closer to the first pivot arm than the second pivot arm. At least one of the first spring assembly and the second spring assembly may include a spring disposed about co-axial damper. A center of gravity of the mobility vehicle may be positioned approximately at the midpoint between a vertical line passing through a point at which the first spring assembly is coupled to the frame and a vertical line passing through a point at which the second spring assembly is coupled to the frame.

The foregoing summary, as well as the following detailed description of embodiments of the mobility vehicle, will be better understood when read in conjunction with the appended drawings of an exemplary embodiment. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. For example, although not expressly stated herein, features of one or more various disclosed embodiments may be incorporated into other of the disclosed embodiments.

Referring to the drawings in detail, wherein like reference numerals indicate like elements throughout, there is shown in <FIG> a mobility vehicle, generally designated <NUM>, in accordance with an exemplary embodiment of the present invention. In some embodiments, the mobility vehicle is a wheelchair.

The mobility vehicle <NUM> includes a frame <NUM>. Frame <NUM> may be a two-piece welded frame. In one embodiment, frame <NUM> includes a left side 22a and a right side 22b. Frame <NUM> may further comprise a three-sided box frame having a bottom panel (e.g., formed of left side 22a and right side 22b), a left panel 23a and a right panel 23b. In one embodiment, left panel 23a and the left side 22a of a bottom panel are a single continuous material. In some embodiments, right panel 23b and right side 22b are of a single continuous material. In some embodiments bottom panel <NUM> includes front panel 21a and rear panel 21b. In some embodiments, front panel 21a and 21b are separated by a gap 21c. In some embodiments, one or more drive wheels <NUM> are coupled to the frame <NUM>. In some embodiments, a motor <NUM> is coupled to the drive wheel <NUM> to rotate the drive wheel <NUM> about a drive wheel axis <NUM>. In some embodiments, the mobility vehicle <NUM> includes two drive wheels <NUM> with a motor <NUM> coupled to each of the drive wheels <NUM> such that each drive wheel is controllable independently of the other drive wheel <NUM>. In some embodiments, the motor is a brushed DC motor (e.g., a Linix <NUM>-pole motor) with single-stage gearbox.

The motor <NUM>, in some embodiments, is connected to a controller (not show) configured to receive an input from a user (e.g., via a joystick, sip and puff controller, or voice command). In some embodiments, the controller is configured to send a signal to the motor <NUM> in response to receiving a signal from the user to move the mobility vehicle <NUM>. In some embodiments, the mobility vehicle <NUM> does not include a motor and the drive wheels are manually powered (e.g., rotating wheel by hand or turning a crank coupled to the drive wheel).

Referring to <FIG>, the mobility vehicle <NUM> is shown with a drive wheel <NUM> removed for ease of discussion. A first pivot arm <NUM> is coupled to the frame <NUM> and the drive wheel <NUM>. In some embodiments, the first pivot arm <NUM> is movably coupled to the frame <NUM>. In some embodiments, the first pivot arm <NUM> is pivotable relative to the frame <NUM>. In some embodiments, the first pivot arm <NUM> can pivot relative to the frame <NUM> about a point <NUM> where the first pivot arm <NUM> is coupled to the frame <NUM>. In some embodiments, the first pivot arm <NUM> can pivot relative to the frame <NUM> to account for uneven terrain (e.g., by maintaining a seat in a generally horizontal orientation) and provide a smoother ride for a user of the mobility vehicle <NUM> than a mobility vehicle that does not include a first pivot arm.

In some embodiments, the length of the first pivot arm <NUM>, and thus the distance of the drive wheel <NUM> to a midpoint of the mobility vehicle <NUM>, can be selected to provide stability to the mobility vehicle <NUM> (e.g., a longer distance may provide a more stable mobility vehicle). In some embodiments, the length of the first pivot arm <NUM> is selected to provide a mobility vehicle with a relatively small footprint. In some embodiments, the first pivot arm <NUM> is coupled to a gear box <NUM> and the gear box <NUM> is coupled to the motor <NUM>. In some embodiments, gear box <NUM> is a single stage gear box. In some embodiments, gear box <NUM> includes an axle coupled to drive wheel <NUM> to rotate the drive wheel. In some embodiments, fender <NUM> is coupled to the first pivot arm <NUM> to prevent unintended contact between drive wheel <NUM> and foreign objects.

In some embodiments, the first pivot arm <NUM> includes an anti-tip element <NUM> (e.g., a wheel). In some embodiments, drive wheel <NUM> is positioned between the anti-tip element <NUM> and the midpoint of the mobility vehicle <NUM>. In some embodiments, the anti-tip element <NUM> is configured to be positioned to avoid contact with the ground when the mobility vehicle <NUM> is on a horizontal ground surface. In some embodiments, the first pivot arm <NUM> is configured and dimensioned to cause the anti-tip element <NUM> to move relative to the drive wheel axis <NUM> when the first pivot arm <NUM> pivots relative to frame <NUM>. In some embodiments, the anti-tip element <NUM> is detachably coupled to the first pivot arm <NUM> (e.g., via a threaded connector, magnet, or rivet).

In some embodiments, the first pivot arm <NUM> includes a first plate <NUM> and a second plate <NUM> coupled to the first plate <NUM> (<FIG>). In some embodiments, first plate <NUM> and second plate <NUM> are a unitary construct. In some embodiments, the first plate <NUM> is configured to be coupled to the gear box <NUM> and the second plate <NUM> is configured to be coupled to the anti-tip element <NUM>. In some embodiments, the orientation of the second plate <NUM> to the first plate <NUM> is adjustable.

In some embodiments, the mobility vehicle <NUM> includes a caster wheel <NUM> configured to rotate about a caster stem axis <NUM> (<FIG>) and caster axis <NUM>. In some embodiments, the caster wheel <NUM> is configured to engage the ground during operation of the mobility vehicle <NUM>. A second pivot arm <NUM> is coupled to the frame <NUM> and the caster wheel <NUM>. In some embodiments, the second pivot arm <NUM> is pivotable relative to the frame <NUM> about a point <NUM> (<FIG>) where the second pivot arm <NUM> is coupled to the frame <NUM>. In some embodiments, second pivot arm <NUM> is pivotable relative to the frame <NUM> independently of first pivot arm <NUM>. In some embodiments, mobility vehicle <NUM> includes a plurality of caster wheels <NUM> and second pivot arms <NUM>. In some embodiments, each of the plurality of caster wheels <NUM> and second pivot arms <NUM> are pivotable independently of another of the plurality of caster wheels <NUM> and second pivot arms <NUM>.

The first pivot arm <NUM> is coupled to the frame <NUM> at a first rod <NUM> (<FIG>). The first rod <NUM> extends from a right side of frame <NUM> to a left side of frame <NUM>. In some embodiments, the first pivot arm <NUM> on the left side of the mobility vehicle <NUM> and the first pivot arm <NUM> on the right side of the mobility vehicle <NUM> are each coupled to the first rod <NUM>. In some embodiments, the first rod <NUM> is fixed relative to the frame <NUM> such that the first rod <NUM> does not rotate as the first pivot arm <NUM> rotates relative to the frame <NUM>.

Second pivot arm <NUM> is coupled to frame <NUM> at a second rod <NUM>. Second rod <NUM> extends from a right side of frame <NUM> to a left side of frame <NUM>. In some embodiments, the second pivot arm <NUM> on the left side of the mobility vehicle <NUM> and the second pivot arm <NUM> on the right side of the mobility vehicle <NUM> are each coupled to the second rod <NUM>. In some embodiments, the second rod <NUM> is fixed relative to the frame <NUM> such that the second rod <NUM> does not rotate as the second pivot arm <NUM> rotates relative to the frame <NUM>. First rod <NUM> and second rod <NUM> are fixedly attached to the frame <NUM> (e.g., via welding) in a configuration to stiffen the frame <NUM>. The first rod <NUM> and second rod <NUM> are coupled to frame <NUM> such that the longitudinal axis of each rod <NUM>, <NUM> is below a bottom panel of frame <NUM>. A stiffening bridge <NUM> is disposed from first rod <NUM> to second rod <NUM>. In some embodiments, the bridge <NUM> is an outermost point of the frame <NUM>. In some embodiments, the bridge <NUM> and first pivot arm <NUM> are co-planar. In some embodiments, bridge <NUM> is configured to provide a distinctive ornamental shape. The mobility vehicle <NUM> includes a suspension assembly <NUM>. Suspension assembly <NUM> is coupled to frame <NUM>. In some embodiments, suspension assembly <NUM> includes at least one of a shock, a damper, or a coil-over configuration. In some embodiments, suspension assembly <NUM> includes a first spring assembly <NUM> and a second spring assembly <NUM>. In some embodiments, the first spring assembly <NUM> is coupled to the first pivot arm <NUM> (e.g., via threaded anchor, dowel, or axle). In some embodiments, first spring assembly <NUM> is coupled to first pivot arm <NUM> in a rotatable or pivotable configuration. First spring assembly <NUM> may be rotatable relative to the first pivot arm <NUM>. In some embodiments, the second spring assembly <NUM> is coupled to the second pivot arm <NUM> (e.g., via threaded anchor, dowel, or axle). In some embodiments, second spring assembly <NUM> is coupled to second pivot arm <NUM> in a rotatable or pivotable configuration (e.g., such that it is rotatable or pivotable relative to second pivot arm <NUM>). In some embodiments, at least one of the first spring assembly <NUM> and the second spring assembly <NUM> include a spring <NUM> disposed about a damper <NUM>. In some embodiments, damper <NUM> has a linear damping rate. In some embodiments, damper <NUM> has a damping rate that is light (e.g., approximately <NUM> to <NUM> lbf-s/in) in compression and medium-light (e.g., approximately <NUM> to <NUM> lbf-s/in) in rebound. In some embodiments, spring <NUM> and damper <NUM> are co-axial. In some embodiments, spring <NUM> is disposed co-axially about damper <NUM>.

In some embodiments, a ratio of the vertical travel distance, relative to the frame, of drive wheel <NUM> and/or castor wheel <NUM> to a respective one of first spring assembly <NUM> and the second spring assembly <NUM> about <NUM>:<NUM>. In some embodiments the foregoing ratio is substantially linear throughout the entire movement of one or more of the drive wheel(s) and/or castor wheel(s). <FIG> illustrates an embodiment of the foregoing ratios of drive wheel <NUM> (v. first spring assembly <NUM>) and castor wheel <NUM> (v. second spring assembly <NUM>). In some embodiments, as illustrated in <FIG>, one of spring assembly is configured to produce a stiffer response than another spring assembly. As illustrated in <FIG>, second spring assembly <NUM> is configured to produce a stiffer response to the vertical movement of castor wheel <NUM> than first spring assembly <NUM> produces in response to vertical movement of drive wheel <NUM>. This differential in stiffness performance may be true even where second spring assembly <NUM> and first spring assembly <NUM> as substantially identical. The difference in such case being attributed to the configuration of the respective spring assemblies as they are coupled to their respective pivot assemblies. In some embodiments, the ratio of vertical travel distance, TDv, of a first pivotable wheel (e.g., drive wheel <NUM> or castor wheel <NUM>) relative to frame <NUM> as the pivotable wheel pivots about the frame (e.g., about point <NUM> or <NUM> respectively) to compression of a respective spring assembly (e.g., spring assembly <NUM> or <NUM> respectively), SAC, is about <NUM>:<NUM>. In some embodiments, the ratio of TDV: SAC is about <NUM>:<NUM>. In some embodiments, the ratio TDV: SAC is different from front pivot wheel/spring assembly combinations than for rear pivot wheel/spring assembly combinations. In some embodiments, TDV: SAC for one or both of front or rear wheel/spring assemblies is about <NUM>:<NUM>; about <NUM>:<NUM>; about <NUM>: <NUM>; about <NUM>:<NUM>; about <NUM>:<NUM>; about <NUM>:<NUM>; about <NUM>:<NUM> or about <NUM>: <NUM>. In some embodiments, TDV: SAC for one or both of front or rear wheel/spring assemblies is up to <NUM>:<NUM>; up to <NUM>:<NUM>; up to <NUM>:<NUM>: up to <NUM>:<NUM>; up to <NUM>:<NUM>. In some embodiments, the first spring assembly <NUM> and/or second spring assembly <NUM> are configured to provide a consistent damping rate (e.g., the damping rate is substantially constant throughout the travel length of the respective pivot wheel) through movement of the drive wheel <NUM> or caster wheel <NUM> along an arc.

Table <NUM> reproduced below, reflects performance of exemplary front suspension and rear suspension.

In some embodiments, the first spring assembly <NUM> or second spring assembly <NUM> have a maximum travel distance along the spring axis of about <NUM> inch, about <NUM> inches, about <NUM> inches, about <NUM> inches, about <NUM> inches, about <NUM> inches, or about <NUM> inches.

In some embodiments, the first spring assembly <NUM> is disposed about a first spring axis <NUM> and the second spring assembly <NUM> is disposed about a second spring axis <NUM> (<FIG>). In some embodiments, the first spring axis <NUM> and the second spring axis <NUM> are disposed relative to each other at an angle <NUM> of about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, no greater than <NUM>°, no greater than <NUM>°, no greater than <NUM>°, no greater than <NUM>°, no greater than <NUM>°, no greater than <NUM>°, no greater than <NUM>°, or no greater than <NUM>°. In some embodiments, the first spring axis <NUM> is closer to horizontal than the second spring axis <NUM>. In some embodiments, the second spring axis <NUM> is closer to horizontal than the first spring axis <NUM>.

In some embodiments, the second pivot arm <NUM> includes a first arm segment <NUM> and a second arm segment <NUM> (<FIG>). In some embodiments, the first arm segment <NUM> is substantially linear. In some embodiments, the first arm segment <NUM> extends at least from a point <NUM> where the second pivot arm <NUM> is coupled to frame <NUM> through a point <NUM> where the second pivot arm <NUM> is coupled to the second spring assembly <NUM>. In some embodiments, the second arm segment <NUM> extends at least from a point <NUM> where the second pivot arm <NUM> is coupled to the second spring assembly <NUM> to caster stem axis <NUM>.

In some embodiments, the second arm segment <NUM> extends from the first arm segment <NUM> to at least a caster stem axis <NUM>. In some embodiments, the second spring axis <NUM> is approximately normal to the first arm segment <NUM> when the mobility vehicle <NUM> is on substantially horizontal ground. In some embodiments, second spring axis <NUM> is substantially tangent to an arc that would be formed by the translation of point <NUM> pivoting about point <NUM>. In some embodiments, second spring axis <NUM> is at an angle with the tangent to an arc that would be formed by the translation of point <NUM> pivoting about point <NUM>. In some embodiments the formed angle is up to <NUM> degrees, up to <NUM> degrees, up to <NUM> degrees, about <NUM> degree, about <NUM> degrees, about <NUM> degrees, about <NUM> degrees or about <NUM> degrees.

In some embodiments, a center of gravity of the mobility vehicle <NUM> (with the user seated on the completed vehicle) is positioned approximately at a midpoint between a vertical line <NUM> passing through a point <NUM> at which the first spring assembly <NUM> is coupled to frame <NUM> and a vertical line <NUM> passing through a point <NUM> at which the second spring assembly <NUM> is coupled to frame <NUM>. In some embodiments, the center of gravity of the mobility vehicle <NUM> is positioned between line <NUM> and line <NUM> when the mobility vehicle <NUM> is on horizontal ground and the center of gravity is not between line <NUM> and line <NUM> when the mobility vehicle <NUM> is on an incline or decline.

In some embodiments, a horizontal projection of a first line <NUM> (e.g., as illustrated in <FIG>) passes through point <NUM> and point <NUM>. In some embodiments, a horizontal projection of a second line <NUM> passes through a point <NUM> at which the first spring assembly <NUM> is coupled to the first pivot arm <NUM> and point <NUM>. In some embodiments, the horizontal projection of the first line <NUM> intersects the horizontal projection of the second line <NUM> at intersection <NUM>. In some embodiments, intersection <NUM> is closer to the first pivot arm <NUM> than the second pivot arm <NUM>. In some embodiments, an angle <NUM> between the horizontal projection of the first line <NUM> and the horizontal projection of the second line <NUM> is about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, about <NUM>° to about <NUM>°, or about <NUM>° to about <NUM>°.

It will be appreciated by those skilled in the art that changes could be made to the exemplary embodiments shown and described above. 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 scope of the present invention as defined by the claims. The words "right", "left", "lower" and "upper" designate directions in the drawings to which reference is made. 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".

Claim 1:
A mobility vehicle (<NUM>) comprising:
a frame (<NUM>);
a first pivot arm (<NUM>) coupled to the frame (<NUM>) and coupled to a drive wheel (<NUM>);
a second pivot arm (<NUM>) coupled to the frame (<NUM>) and coupled to a ground engaging caster wheel (<NUM>); and
a suspension assembly (<NUM>) coupled to the frame (<NUM>);
wherein the first pivot arm (<NUM>) is coupled to the frame (<NUM>) at a first rod (<NUM>) extending from a left side of the frame (<NUM>) to a right side of the frame (<NUM>)and the second pivot arm (<NUM>) is coupled to the frame (<NUM>) at a second rod (<NUM>) extending from the left side of the frame (<NUM>) to the right side of the frame (<NUM>), each of the first rod (<NUM>) and second rod (<NUM>) fixedly attached to the frame (<NUM>) in a configuration to stiffen the frame (<NUM>), and
wherein the mobility vehicle (<NUM>) further comprises a stiffening bridge (<NUM>) disposed from the first rod (<NUM>) to the second rod (<NUM>),
characterized in that the first rod (<NUM>) and the second rod (<NUM>) are coupled to the frame (<NUM>) such that the longitudinal axis of each rod (<NUM>, <NUM>) is below a bottom panel of the frame (<NUM>).