A system for monitoring shopping carts or other human-propelled carts includes wireless access points that communicate on a wireless network with wheel assemblies of the carts. The system is capable of monitoring a path followed by a cart in a store or building, and using the path (optionally together with other criteria) to determine whether to authorize the cart to exit. For example, if a shopping cart fails to pass through a checkout lane of a store, the system may perform an action that blocks or inhibits the shipping cart from exiting the store.

A system for monitoring shopping carts or other human-propelled carts includes wireless access points that communicate on a wireless network with wheel assemblies of the carts. The system is capable of monitoring a path followed by a cart in a store or building, and using the path (optionally together with other criteria) to determine whether to authorize the cart to exit. For example, if a shopping cart fails to pass through a checkout lane of a store, the system may perform an action that blocks or inhibits the shipping cart from exiting the store. The wheel assemblies may include LEDs or other visual indicators that alert store personnel when a wheel assembly is in a particular state.

A system for monitoring shopping carts or other human-propelled carts includes wireless access points that communicate bi-directionally on a wireless network with wheel assemblies of the carts. The system supports both unicast and multicast command transmissions from the access points to the wheel assemblies, including multicast transmissions in which the target wheel assemblies are specified in terms of their states. For example, an access point can transmit a command that is addressed to all wheel assemblies that are locked, or to all wheel assemblies that are moving.

An accessory plate accommodates a caliper brake disc system in either a retrofit kit or in the original construction of wheelbarrows, hand carts and other wheeled, slow speed vehicles. The accessory plate or extension plate is secured to an axle or hub providing attachment to a caliper system. The accessory plate may be modified to accept other accessories, including but not limited to electric motors, drum brake arms and accessories, lights, battery packs or other accessories pertinent to the vehicle's enhanced operation. A hub system may be optionally used and may help to accommodate the installation of an accessory plate and/or rotor disc and/or drum brake or drum brake actuator.

A vehicle tracking system includes a wheel assembly containing sensor circuitry capable of sensing one or more types of conditions, such as wheel rotation, wheel vibration caused by skidding, and specific electromagnetic and/or magnetic signals indicative of particular wheel locations. The wheel assembly may also include a brake mechanism. The wheel assemblies may be mounted on shopping carts and used to collect and monitor shopping cart status and location data via a wireless network. In one embodiment, the wheel assembly communicates via a wired or wireless connection with a handlebar mounted display unit of the cart.

A wheelchair (100) includes a chassis (101) defining a seat (102), a backrest (103), one or more armrests (104,105), and an undercarriage (106). One or more front caster wheels (118,119) are coupled to, and selectively detachable from, the undercarriage. One or more rear wheel assemblies (120,121) each include a rear wheel (125), an axle (127), and a mounting post (129) extending distally from the axle at a substantially orthogonal angle relative to the axle. One or more quick release devices (130,131) couple each mounting post of each rear wheel assembly to the undercarriage such that the each the one or more rear wheel assemblies is selectively detachable from the undercarriage.

A navigation system uses a dead reckoning method to estimate an object's present position relative to one or more prior positions. In some embodiments, the dead reckoning method determines a change in position from the object's heading and speed during an elapsed time interval. In embodiments suitable for use with wheeled objects, the dead reckoning method determines the change in position by measuring the heading and the amount of wheel rotation. Some or all of the components of the navigation system may be disposed within a wheel, such as a wheel of a shopping cart.

A mobility walker comprising a pair of rear legs and a pair of front legs, each configured to support the mobility walker on the ground. The mobility walker further comprises a transverse handle extending laterally across a width of the mobility walker. The transverse handle is configured to be grasped by a user when operating the mobility walker. At least sixty percent of the length of each of the front legs is formed with a concave curvature, as viewed from a front of the mobility walker.

A walking aid that assists a user in walking in an upright position. The walking aid may include a rear lower frame structure, a front lower frame structure, a first front wheel coupled to a first front lower frame member, a second front wheel coupled to a second front lower frame member, a first rear wheel coupled to the first rear lower frame member, a second rear wheel coupled to the second rear lower frame member, an upper frame structure comprising a first upper frame member, a second upper frame member, a first forearm support, and a second forearm support, a first pivot and latch mechanism pivotally coupling the first upper frame member and the first rear lower frame member together, and a second pivot and latch mechanism pivotally coupling the second upper frame member and the second rear lower frame member together.

A vehicle tracking system includes a wheel assembly containing sensor circuitry capable of sensing various types of conditions, such as specific electromagnetic and/or magnetic signals indicative of particular wheel locations. The sensor circuitry is coupled to an RF transceiver, which may but need not be included within the wheel. The wheel may also include a brake mechanism. In one embodiment, the wheels are placed on shopping carts and are used to collect and monitor shopping cart status and location data via a wireless network. In some embodiments, the wheel assemblies detect that they have entered into particular zones by measuring received signal strengths of received command transmissions, and by comparing these measurements to thresholds that are used to define zone boundaries.