Wheelchairs and scooters are an important means of transportation for a significant portion of society. Whether manual or powered, these vehicles 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, driveways, and other paved surface interfaces. This degree of independence can also be limited if the vehicle is required to ascend inclines or descend declines.
Most wheelchairs have front and rear casters to stabilize the chair from tipping forward or backward and to ensure that the drive wheels are always in contact with the ground. The caster wheels are typically much smaller than the driving wheels and located both forward and rearward of the drive wheels. Though this configuration provides the wheelchair with greater stability, it can hamper the wheelchair's ability to climb over obstacles such as, for example, curbs or the like, because the size of the front casters limits the height of the obstacle that can be traversed.
Though equipped with front and rear suspended casters, most mid-wheel drive wheelchairs exhibit various degrees of tipping forward or rearward when descending declines or ascending inclines. This is because the suspensions suspending the front or rear stabilizing casters are compromised so that they are not made too rigid, which would prevent tipping and also not provide much suspension, or are made too flexible thereby effectively not providing any degree of suspension or stabilization.
USPTO Backgrounds
USPTO Backgrounds