A mobile robot configured to drive on a surface with irregularities, comprising: a chassis having a front end facing a forward direction of travel, a back end, a first side, and a second side. There is a first drive wheel rigidly affixed to the chassis proximate the first side and interconnected to a motor to propel it. There is a second drive wheel rigidly affixed to the chassis proximate the second side and interconnected to a motor to propel it. A first caster assembly is rigidly affixed to the chassis proximate the front end and includes a first caster wheel configured to rotate about a first swivel axis. A second caster assembly is rigidly affixed to the chassis proximate the back end and includes a second caster wheel configured to rotate about a second swivel axis and it includes a compliant member to absorb the irregularities.

A skateboard includes a board body having a first section and a second section, at least a first wheel set connected to the first section, and at least two second wheel sets connected to the second section. The first wheel set includes a first base protruding from the first section. Each second wheel set includes a second base protruding from the second section and defines a reference line passing through a center of the second base. Both of the bases slope at an angle of 5 to 35 degrees respectively. An angle of not more than 60 degrees is formed between the reference line and a baseline passing axially through a center of the board body. The skateboard moves forward when the wheel sets are triggered by twisting a body of a user and a moving direction is changeable by shifting a center of gravity of the user.

A self-leveling caster assembly includes a caster frame and a castor fork which is configured to pivot relative to the caster frame. A spring or other biasing mechanism biases the caster fork away from the caster frame, to maintain contact between the ground and a wheel supported by the caster fork along a travel range of the wheel. Even if a frame supporting the self-leveling caster assembly is bent, pulling the wheel away from the ground, the biased caster fork will maintain contact between the ground and the wheel, allowing continued use of a shopping cart or other wheeled apparatus including the self-leveling caster assembly.

A selectively locking rotational bearing element includes at least one bearing element supporting an outer race for rotational movement and a plurality of locking elements disposed circumferentially about an inner surface of the outer race. An actuator selectively moves the plurality of locking elements into engagement with the outer race to restrict rotational movement of the outer race and selectively move the plurality of locking elements away from engagement with the outer race such that the outer race is free to rotate relative to the locking elements.

A selectively locking rotational bearing element includes at least one bearing element supporting an outer race for rotational movement and a plurality of locking elements disposed circumferentially about an inner surface of the outer race. An actuator selectively moves the plurality of locking elements into engagement with the outer race to restrict rotational movement of the outer race and selectively move the plurality of locking elements away from engagement with the outer race such that the outer race is free to rotate relative to the locking elements.

Several solutions are described for making it easier to move a surgical robotics patient table, either from rest or to turn it. The table has a base, a support, and a table top on which the patient is supported. A number of casters are mounted to a body of the base. In one case, controllable jacks lift the body to release the casters thereby allowing them to swivel to a desired orientation. In another case, a drive assembly is rotatably coupled to the body of the base and includes an electric drive motor and a drive wheel to drive the table across the floor. Other aspects are also described and claimed.

A spacing bar of a wheelchair frame comprising an elongated structural body having a pair of opposite ends, each of the opposite ends having a C-shaped clamp configured for being clamped to respective lateral frame members of the wheelchair frame, wherein the elongated structural body and the C-shaped clamps are integrally made of a monocoque composite construction, and a tightening assembly for each of the C-shaped clamps, the tightening assemblies being arranged in the spacing bar to loosen and tighten the C-shaped clamps to the respective lateral frame members. A wheelchair frame comprising: a pair of lateral frame members configured to support at least a seat, and front and rear wheel units, the lateral frame members each having an elongated frame portion in a seating zone of the wheelchair frame, and a spacing bar having an elongated structural body and a pair of opposite ends, each of the opposite ends having a connector configured for being clamped to a respective one of the lateral frame member of the wheelchair frame, wherein each of the connectors forms a joint with the respective one of the elongated frame portions constraining the spacing bar to movement of the spacing bar axially along the pair of the elongated frame portion, a tightening assembly for each of the connectors, the tightening assemblies being arranged in the spacing bar to loosen and tighten the connectors to block or allow movement of the spacing bar along the pair of the lateral frame members.

A spacing bar of a wheelchair frame comprising an elongated structural body having a pair of opposite ends, each of the opposite ends having a C-shaped clamp configured for being clamped to respective lateral frame members of the wheelchair frame, wherein the elongated structural body and the C-shaped clamps are integrally made of a monocoque composite construction, and a tightening assembly for each of the C-shaped clamps, the tightening assemblies being arranged in the spacing bar to loosen and tighten the C-shaped clamps to the respective lateral frame members. A wheelchair frame comprising: a pair of lateral frame members configured to support at least a seat, and front and rear wheel units, the lateral frame members each having an elongated frame portion in a seating zone of the wheelchair frame, and a spacing bar having an elongated structural body and a pair of opposite ends, each of the opposite ends having a connector configured for being clamped to a respective one of the lateral frame member of the wheelchair frame, wherein each of the connectors forms a joint with the respective one of the elongated frame portions constraining the spacing bar to movement of the spacing bar axially along the pair of the elongated frame portion, a tightening assembly for each of the connectors, the tightening assemblies being arranged in the spacing bar to loosen and tighten the connectors to block or allow movement of the spacing bar along the pair of the lateral frame members.

A wheelchair can comprise: a frame comprising an upper portion and a lower portion that is coupled to the upper portion so that the upper portion is vertically adjustable with respect to the lower portion. A pair of drive wheels can be coupled to the frame. A plurality (e.g., a pair) of casters are coupled to the frame. Each caster can have a respective swivel axis. At least one caster of the plurality of casters can be configured to be locked to prevent swiveling about its respective swivel axis and unlocked to enable swiveling about its respective swivel axis.

A system of bracket assemblies for a wheelchair comprises a pair of bracket assemblies adapted to be connected to respective sides of a seat frame of the wheelchair. Each of the bracket assemblies has a base adapted to be secured to a seat frame member of the seat frame, an arm adapted to be secured to a backrest frame member of a backrest frame, and a pivot pivotally connecting the base to the arm for rotational movement of the arm relative to the base. One or more blocking mechanism blocks the rotational movement of the arm relative to the base in a use orientation of the backrest frame. A rod having opposed ends connected to the base of the pair of the bracket assemblies for spacing the bracket assemblies away from one another. A rear wheel unit is also provided.