Abstract: A writing instrument may include an upper barrel rotatably connected to a lower barrel. Writing fluid reservoirs may be housed in the upper barrel. A writing tip secured to the lower barrel may be in selective fluid communication with the writing fluid reservoirs. The upper barrel may be rotatable relative to the lower barrel of the writing instrument.

Abstract: An exercise apparatus may provide a novel linkage assembly suitable for linking circular motion to relatively more complex, generally elliptical motion. Left and right rocker links may be rotatably mounted on a frame rotatable about a first axis. Left and right rocker linkages may be mounted on the frame rotatable about a second axis. Left and right force receiving members may be movably connected between respective rocker links and rocker linkages in such a manner that the force receiving members move through paths of motion which are fixed, adjustable or variable.

Abstract: In an oscillating fin propulsion apparatus adapted for use by a disabled diver, a propulsion force may be produced by a fin adapted to sweep back and forth in a generally transverse direction relative to the traveling direction of the diver. The fin may be mounted on a scuba tank operatively connected to drive members that may be reciprocated by the diver. The oscillating fin may provide a propulsive force propelling the diver forward during both oscillating directions of the fin.

Abstract: An exercise apparatus may include a frame configured to rest on a floor surface. Left and right foot members may be mounted on respective sides of a stanchion connected to the frame. The foot members may include foot platforms securely fixed to a lower distal end thereof. Toe plates may be pivotally secured to the foot platforms. The toe plates may be rotatable for engagement with a trigger switch operative connected to a display.

Abstract: In a gravity filtration system, upper and lower fluid reservoirs may be mated together. Unfiltered fluid may be supplied to the upper reservoir. One or more filters provide fluid communication between the upper and lower fluid reservoirs. Fluid may pass through the filters into the lower fluid reservoir. The weight of the fluid in the gravity filtration system may be monitored to maximize the fluid flow rate without loss of fluid by supporting the fluid reservoirs on a moveable platform interconnected to a stationary base by a force reactive linkage. Automatic fill components may be provided for automatically actuating a fluid supply valve connected to an unfiltered fluid source. As filtered fluid is withdrawn from the lower reservoir, actuation of the fluid supply valve to an open position may permit unfiltered fluid to be supplied to the upper reservoir. Supply of unfiltered fluid to the upper reservoir may be stopped upon actuation of the fluid supply valve to the closed position.

Abstract: A yoga paddleboard may include a yoga board body having a hole extending therethrough. The hole may be formed at the approximate lateral and longitudinal center of the paddleboard. The hole may be sized and configured to support a yoga ball pressed in the hole to establish an interfacing friction connection therebetween. The yoga ball may be used to perform yoga exercises while floating on the paddleboard. Alternative embodiments may include yoga ball supports configured to support yoga balls of different sizes and/or multiple yoga balls for use with the paddleboard.

Abstract: In an oscillating fin propulsion apparatus operatively connected to a scuba diver moving on or through a body of water, a propulsive force may be produced by a pair of fins adapted to sweep back and forth in a generally transverse direction relative to the longitudinal axis of the scuba diver's body. The fins may be mounted on opposite sides of a frame detachably secured to a scuba tank. The fins may be rotatable in an oscillatory motion about respective axes coplanar to the center longitudinal axis of the frame. Drive members operable by the scuba diver may be operatively connected to the fins. The oscillating fins may provide a propulsive force to propel the scuba diver longitudinally forward during both oscillating directions of the fins as they sweep back and forth.

Abstract: A swim fin may include a foot pocket configured to receive a foot of a swimmer and a fin blade extending from the foot pocket. The fin blade may be relatively stiff and flex about a hinge region proximate the foot pocket. Fin rails may extend along the lateral edges of the fin blade. The fin rails may include a fin spine comprising a plurality of fin spine segments joined in linear configuration. The swim fin may be configured to provide a swim fin with predetermined hydrodynamic characteristics. The swim fin may flex within a maximum angle of attack that may be variable and dynamically changed, within the predetermined maximum attack angle range, as a function of the kicking force generated by a swimmer during a kicking cycle.

Abstract: A water propulsion apparatus operatively connected to a body moving on or through a body of water, may produce a propulsive force by sweeping fins in an oscillating motion in a generally transverse direction relative to a longitudinal axis of the body. The fins may be mounted on opposite sides of a frame and are rotatable about a first axis coplanar to the center longitudinal axis of the frame. Drive members rotatable about a second axis that is canted relative to the first axis may be operatively connected to the fins. The oscillatory motion of the fins may be controlled by torque applied at the canted second axis by reciprocating the drive members in a generally vertical plane parallel to the center longitudinal axis of the frame. The oscillating fins may provide a propulsive force during both oscillating directions of the fins as they sweep back and forth.

Abstract: In an exercise machine, foot platforms may travel in inclined circular paths to establish three dimensional operational characteristics. Platform support members may be rotationally synchronized by connected mechanical components such that they are maintained out of phase with each other by one half of a cycle or 180 degrees in counter rotational directions. Crank synchronization in an inclined plane during operation of the exercise machine may provide three-dimensional foot travel in vertical, lateral and longitudinal directions.

Abstract: A variable stride exercise apparatus may provide a novel linkage assembly and corresponding exercise apparatus suitable for linking circular motion to relatively more complex, generally elliptical motion. Left and right cranks are rotatably mounted on a frame. A foot supporting linkage is movably connected between a rocker and the left and right cranks in such a manner that may provide variable paths of motion controlled by a user of the apparatus.

Abstract: In an exercise machine, foot platforms may travel in inclined circular paths to establish three dimensional operational characteristics. Platform support members may be rotationally synchronized by connected mechanical components such that they are maintained out of phase with each other by one half of a cycle or 180 degrees in counter rotational directions. Crank synchronization in an inclined plane during operation of the exercise machine may provide three-dimensional foot travel in vertical, lateral and longitudinal directions.

Abstract: A water propulsion assembly operatively connected to a watercraft moving on or through a body of water, may produce a propulsive force by sweeping fins in an oscillating motion in a generally transverse direction relative to a longitudinal axis of the watercraft. The fins may be rotatable about a first axis coplanar to the center longitudinal axis of the watercraft. Drive members rotatable about a second axis that is canted relative to the first axis may be operatively connected to the fins. The oscillatory motion of the fins may be controlled by torque applied at the canted second axis by reciprocating the drive members in a plane generally parallel to the center longitudinal axis of the watercraft. The oscillating fins may provide a propulsive force during both oscillating directions of the fins as they sweep back and forth.

Abstract: A writing instrument may include an upper pen barrel rotatably connected to a lower pen barrel. A spool valve and fluid reservoirs may be housed in the upper pen barrel. A writing tip secured to the lower pen barrel may be in selective fluid communication with the fluid reservoirs. The upper pen barrel may be rotatable relative to the lower pen barrel of the writing instrument.

Abstract: In a tri-flush toilet, three operational flush modes may be provided to enable water conservation. The toilet may include a third mode operating a peristaltic pump to reduce the water consumption per flush. The peristaltic pump is operably connected to evacuate fluids and/or solids form the toilet bowl.

Abstract: A swim fin and a method proving thrust propulsion during a swimmer's kicking cycle may include a foot pocket and a fin blade extending from the foot pocket. Fin rails may extend along the lateral edges of the fin blade. The fin rails may include an integral fin spine or separately assembled fin spine configured to provide a swim fin with predetermined hydrodynamic characteristics.

Abstract: An exercise apparatus having homolateral and contralateral modes of operation is disclosed. The exercise apparatus may include a frame supporting generally vertically oriented reciprocating members spaced apart and in substantial parallel relationship to one another. The reciprocating members may include foot supports fixedly secured at the lower distal ends thereof and handlebars rotatably mounted proximate the upper distal ends of the reciprocating members. The handlebars may be selectively locked for homolateral and contralateral operation of the exercise apparatus.

Abstract: A swim fin may include a foot pocket configured to receive a foot of a swimmer and a fin blade extending from the foot pocket. The fin blade may be relatively stiff and flex about a hinge region proximate the foot pocket. Fin rails may extend along the lateral edges of the fin blade. The fin rails may include a fin spine comprising a plurality of fin spine segments joined in linear configuration. The swim fin may be configured to provide a swim fin with predetermined hydrodynamic characteristics. The swim fin may flex within a maximum angle of attack that may be variable and dynamically changed, within the predetermined maximum attack angle range, as a function of the kicking force generated by a swimmer during a kicking cycle.

Abstract: A multi-color writing marker may comprise a tubular marker barrel connected to a motor housing. The marker barrel may house a cartridge removably coupled to a drive shaft connected to a motor. The cartridge may include a plurality of reservoirs containing writing liquids of different colors. A marker tip may be mounted on a distal end of the cartridge. The marker tip supports a plurality of marker nibs corresponding to the number of cartridge reservoirs. Each marker nib may be in fluid communication with a corresponding reservoir. Actuation of the motor spins the cartridge and marker nibs while a user is simultaneous creating a design on the writing surface.

Abstract: In a gravity filtration system, upper and lower fluid reservoirs may be mated together. Unfiltered fluid may be supplied to the upper reservoir. One or more filters provide fluid communication between the upper and lower fluid reservoirs. Unfiltered fluid passes through the filter into the lower filtered fluid reservoir. The weight of the fluid in the gravity filtration system may be monitored to maximize the fluid flow rate without loss of fluid by supporting the fluid reservoirs on a moveable platform interconnected to a stationary base by a force reactive linkage. Automatic fill components may be provided for automatically actuating a fluid supply valve connected to an unfiltered fluid source. As filtered fluid is withdrawn from the lower reservoir, actuation of the fluid supply valve to an open position permits unfiltered fluid to be supplied to the upper reservoir. Supply of unfiltered fluid to the upper reservoir is stopped upon actuation of the fluid supply valve to the closed position.