A step board is attached to a main body in a rotatable manner. The step board is biased toward the upper side due to a tensile force of a spring while taking a position at which the step board is attached to the main body as an axis, and an attachment angle thereof is so fixed by a stopper as to fall within a predetermined angle. On the lower side of the step board, a cylinder unit covering a side surface of the bar-like main body is provided. The cylinder unit is connected to a brake shoe. Accordingly, when the step board is stepped on, the cylinder unit is moved downward so that the brake shoe makes contact with part of a rear wheel, thereby limiting a rotational velocity of the rear wheel.

A method of identifying stairs from footfalls includes receiving a plurality of footfall locations of a robot traversing an environment. Each respective footfall location indicates a location where a leg of the robot contacted a support surface. The method also includes determining a plurality of candidate footfall location pairs based on the plurality of footfall locations. The candidate footfall location pair includes a first and a second candidate footfall location. The method further includes clustering the first candidate footfall location into a first cluster group based on a height of the first candidate footfall location and clustering the second candidate footfall location into a second cluster group based on a height of the second candidate footfall location. The method additionally includes generating a stair model by representing each of the cluster groups as a corresponding stair and delineating each stair based on a respective midpoint between each adjacent cluster group.

A wheel-alternate stair climbing cart at least has one row of wheels (preferably two or more rows of wheels). Each row comprises a plurality of wheels. Two adjacent groups of wheels are intersected. The total length formed by connecting axle centers of a plurality of wheels can at least cross a vertex of three steps. The wheels on the stair at least keep contact with a vertex of two steps. The present invention better solves the problem that a traditional cart is blocked when operating on the stair or is bumpy when moving, and has the advantages of strong weight loading capability, difficult wear and low manufacturing cost.

A wheel-alternate stair climbing cart at least has one row of wheels (preferably two or more rows of wheels). Each row comprises a plurality of wheels. Two adjacent groups of wheels are intersected. The total length formed by connecting axle centers of a plurality of wheels can at least cross a vertex of three steps. The wheels on the stair at least keep contact with a vertex of two steps. The present invention better solves the problem that a traditional cart is blocked when operating on the stair or is bumpy when moving, and has the advantages of strong weight loading capability, difficult wear and low manufacturing cost.

A wheel includes a supporting frame, with a central portion having a center around which the wheel can turn, and a plurality of radial portions extending from the central portion angularly displaced with each other. A housing seat is delimited between two adjacent radial portions. A movable element is radially displaceable between a first working position located at a maximum distance with respect to the center, and a second working position located at a minimum distance with respect to the center of the central portion. The radial portions and the movable element have respective distal sections, with respect to the center, curved with a curvature radius corresponding to the curvature radius of the wheel and being flush with each other. A locking element is displaceable between one locking position, wherein it abuts on the movable element and prevents the radial displacement thereof, and one unlocking position, wherein it allows the radial displacement of the movable element toward the second working position. A returning element of the movable element between the supporting frame and the movable element is configured to bring the movable element back into the first working position. A band made of an elastically deformable material surrounds the distal sections of the plurality of radial portions and the movable element, at the circular perimeter of the wheel.

A wheel includes a supporting frame, with a central portion having a center around which the wheel can turn, and a plurality of radial portions extending from the central portion angularly displaced with each other. A housing seat is delimited between two adjacent radial portions. A movable element is radially displaceable between a first working position located at a maximum distance with respect to the center, and a second working position located at a minimum distance with respect to the center of the central portion. The radial portions and the movable element have respective distal sections, with respect to the center, curved with a curvature radius corresponding to the curvature radius of the wheel and being flush with each other. A locking element is displaceable between one locking position, wherein it abuts on the movable element and prevents the radial displacement thereof, and one unlocking position, wherein it allows the radial displacement of the movable element toward the second working position. A returning element of the movable element between the supporting frame and the movable element is configured to bring the movable element back into the first working position. A band made of an elastically deformable material surrounds the distal sections of the plurality of radial portions and the movable element, at the circular perimeter of the wheel.

A step-climbing attachment for a wheeled chair, the attachment comprising a first wheel having at least a hub and a rim spaced from the hub, the hub and rim defining an inner region, a second wheel having a different diameter than the first wheel, and the second wheel being rotatably mounted to an extending arm, the extending arm being movable relative to the first wheel between a first position and at least one second position by a controllable mechanism, wherein the controllable mechanism is housed at least partially within the inner region of the first wheel, wherein the second wheel is driven by rotation of the first wheel.

A stroller track system is used to facilitate the transporting of a stroller up and down stairs. The stroller track system includes a left tread assembly and a right tread assembly. The left tread assembly and the right tread assembly are used to engage multiple stairs while traversing a set of stairs. This allows the stroller to glide smoothly up or down the stairs. The left tread assembly and the right tread assembly each include a first track and a first stroller-attaching mount. The first track has a greater surface area than a normal wheel, allowing the first track to span a larger section of a staircase. The first stroller-attaching mount is used to attach the first track to a stroller. In alternative versions of the stroller track system, the left tread assembly and the right tread assembly may include additional tracks to further stabilize the stroller.

A stroller track system is used to facilitate the transporting of a stroller up and down stairs. The stroller track system includes a left tread assembly and a right tread assembly. The left tread assembly and the right tread assembly are used to engage multiple stairs while traversing a set of stairs. This allows the stroller to glide smoothly up or down the stairs. The left tread assembly and the right tread assembly each include a first track and a first stroller-attaching mount. The first track has a greater surface area than a normal wheel, allowing the first track to span a larger section of a staircase. The first stroller-attaching mount is used to attach the first track to a stroller. In alternative versions of the stroller track system, the left tread assembly and the right tread assembly may include additional tracks to further stabilize the stroller.

An infant stroller apparatus includes a stroller frame having a leg frame, a stand platform pivotally connected with the leg frame about a pivot axis, and a spring connected with the leg frame. The stand platform is connected with a caster assembly disposed rearward relative to the pivot axis. The spring is configured to bias the stand platform in a direction for displacing the caster assembly downward. In some embodiment, the infant stroller apparatus can include a brake assembly operable to lift the caster assembly of the stand platform in a braking state.