Abstract: A laterally collapsible, user-pushed, four-wheeled rollator, stroller or the like has swiveling front wheels for steering, each mounted in a fork with a vertical post, with a toothed pulley fixed thereto, rotatable in a bearing housing fixed at the front end of right and left side frames. The two swiveling front wheels can swivel to any steering angle but always in unison with each other by virtue of a flexible toothed synchronous belt extending between the toothed pulleys. The interior of each bearing housing closely surrounds each toothed pulley and the belt, preventing any disengagement of the belt from either toothed pulley even when the belt becomes slack when the left and right side frames are folded towards each other. A synchronous chain with sprockets can also be used. Tether means pull the belt/chain rearwardly to a protected position during folding.

Abstract: A laterally collapsible, user-pushed, four-wheeled rollator, stroller or the like has swiveling front wheels for steering, each mounted in a fork with a vertical post, with a toothed pulley fixed thereto, rotatable in a bearing housing fixed at the front end of right and left side frames. The two swiveling front wheels can swivel to any steering angle but always in unison with each other by virtue of a flexible toothed synchronous belt extending between the toothed pulleys. The interior of each bearing housing closely surrounds each toothed pulley and the belt, preventing any disengagement of the belt from either toothed pulley even when the belt becomes slack when the left and right side frames are folded towards each other. A synchronous chain with sprockets can also be used. Tether means pull the belt/chain rearwardly to a protected position during folding.

Abstract: The present invention relates to a wheel suspension for mounting on a frame (3) of a vehicle, which, in its direction of propulsion, is arranged to be able to scale an obstacle (7), the wheel suspension (1) comprises a link element (9) arranged rotatably about a rotation point (R), to which rotation point (R), via the frame (3), can be applied a force (Gx) for propulsion, the link element (9) comprises a first and a second wheel axle (11, 13), the second wheel axle (13) serves as a moment axis (X) about which the link element (9) tends to rotate when a force (F) is applied to the first wheel axle (11) in the direction opposite to the direction of travel. The link element (9) acts as a lever arm by virtue of the rotation point (R) being situated at a distance from an imaginary straight line (L) intersecting the first and the second wheel axle (11, 13) and in a plane transversely to the extent of the moment axis (X).

Abstract: The present invention relates to a wheel suspension for mounting on a frame (3) of a vehicle, which, in its direction of propulsion, is arranged to be able to scale an obstacle (7), the wheel suspension (1) comprises a link element (9) arranged rotatably about a rotation point (R), to which rotation point (R), via the frame (3), can be applied a force (Gx) for propulsion, the link element (9) comprises a first and a second wheel axle (11, 13), the second wheel axle (13) serves as a moment axis (X) about which the link element (9) tends to rotate when a force (F) is applied to the first wheel axle (11) in the direction opposite to the direction of travel. The link element (9) acts as a lever arm by virtue of the rotation point (R) being situated at a distance from an imaginary straight line (L) intersecting the first and the second wheel axle (11, 13) and in a plane transversely to the extent of the moment axis (X).