A rod piece connection device, comprising: a first connection piece and a second connection piece. The first connection piece includes a first rod piece connection end and a first joggle joint end opposite to the first rod piece connection end. Wherein, the first joggle joint end includes a protrusion head tongue portion and a neck portion. The second connection piece includes a second rod piece connection end and a second joggle joint end opposite to the second rod piece connection end. The second joggle joint end is located corresponding to the first joggle joint end for them to form into a joggle joint. The second joggle joint end includes a protrusion bottom groove portion and a pillow portion. Wherein the protrusion head tongue portion is disposed corresponding into the protrusion bottom groove portion, and the neck portion is located corresponding to the pillow portion.

A rod piece connection device, comprising: a first connection piece and a second connection piece. The first connection piece includes a first rod piece connection end and a first joggle joint end opposite to the first rod piece connection end. Wherein, the first joggle joint end includes a protrusion head tongue portion and a neck portion. The second connection piece includes a second rod piece connection end and a second joggle joint end opposite to the second rod piece connection end. The second joggle joint end is located corresponding to the first joggle joint end for them to form into a joggle joint. The second joggle joint end includes a protrusion bottom groove portion and a pillow portion. Wherein the protrusion head tongue portion is disposed corresponding into the protrusion bottom groove portion, and the neck portion is located corresponding to the pillow portion.

A system for use in rehabilitation of a target patient is provided. The system includes at least two bicycle devices for use by the target patient and a second operator other than the target patient. The at least two bicycle devices each include pedals. At least one of the pedals may have at least one sensor mounted thereon for monitoring operation of the first bicycle device and the target's condition. A servomotor is coupled to the pedals for providing gear-like resistance or pedal assistance for the at least two bicycle devices. A controller is programmed to electrically couple the at least two bicycle devices to each other.

A system for use in rehabilitation of a target patient is provided. The system includes at least two bicycle devices for use by the target patient and a second operator other than the target patient. The at least two bicycle devices each include pedals. At least one of the pedals may have at least one sensor mounted thereon for monitoring operation of the first bicycle device and the target's condition. A servomotor is coupled to the pedals for providing gear-like resistance or pedal assistance for the at least two bicycle devices. A controller is programmed to electrically couple the at least two bicycle devices to each other.

A rod piece connection device, comprising: a first connection piece and a second connection piece. The first connection piece includes a first rod piece connection end and a first joggle joint end opposite to the first rod piece connection end. Wherein, the first joggle joint end includes a protrusion head tongue portion and a neck portion. The second connection piece includes a second rod piece connection end and a second joggle joint end opposite to the second rod piece connection end. The second joggle joint end is located corresponding to the first joggle joint end for them to form into a joggle joint. The second joggle joint end includes a protrusion bottom groove portion and a pillow portion. Wherein the protrusion head tongue portion is disposed corresponding into the protrusion bottom groove portion, and the neck portion is located corresponding to the pillow portion.

A rod piece connection device, comprising: a first connection piece and a second connection piece. The first connection piece includes a first rod piece connection end and a first joggle joint end opposite to the first rod piece connection end. Wherein, the first joggle joint end includes a protrusion head tongue portion and a neck portion. The second connection piece includes a second rod piece connection end and a second joggle joint end opposite to the second rod piece connection end. The second joggle joint end is located corresponding to the first joggle joint end for them to form into a joggle joint. The second joggle joint end includes a protrusion bottom groove portion and a pillow portion. Wherein the protrusion head tongue portion is disposed corresponding into the protrusion bottom groove portion, and the neck portion is located corresponding to the pillow portion.

A bicycle is provided that can include front and rear wheels; a handle bar; and top, bottom, head, front seat, and rear seat tube members (each with a longitudinal axis) that form a frame that is suspended between the wheels. A distance between the head tube member and the front seat tube member can be 14 inches or less. The distance can also be one-half or less of the distance between the head tube member and the rear seat tube member. The longitudinal axis of the head tube member can intersect a longitudinal axis of the front seat tube member at 120 inches or less above a riding surface. The rotational planes of the front pedals of a front crankset can overlap a rotational plane of the front wheel. The handle bar rotates about a volume representative of an upper body of a front rider and/or cargo.

A bicycle is provided that can include front and rear wheels; a handle bar; and top, bottom, head, front seat, and rear seat tube members (each with a longitudinal axis) that form a frame that is suspended between the wheels. A distance between the head tube member and the front seat tube member can be 14 inches or less. The distance can also be one-half or less of the distance between the head tube member and the rear seat tube member. The longitudinal axis of the head tube member can intersect a longitudinal axis of the front seat tube member at 120 inches or less above a riding surface. The rotational planes of the front pedals of a front crankset can overlap a rotational plane of the front wheel. The handle bar rotates about a volume representative of an upper body of a front rider and/or cargo.

A transformable bicycle or tricycle is presently provided. The transformable bicycle has a first seat and a second seat disposed rearward or forward of the first seat. At least one of the first seat and the second seat is transformable and has a planar seat and a planar back. The transformable seat is configured and disposed to transform into an enclosure or into a flat planar bench having the planar seat and the planar back substantially in the same plane.

This Tandem bicycle design describes a reduced linear dimension, whereby the inherent polar integrity of the tandem structure is reduced.

Due to the close proximity of the cyclist, balance and coordination is more rapid and spontaneous.

The gear construct is comprised of a system of three cranking sprockets, closely arranged in a forward (one) and rearward pair. The forward and rear gears closest to the bicycle frame; coupled to a timing chain, functions as the timing mechanism. The rearward outer gear functions as the driving gear connected by a power chain to the rear wheel sprocket(s).

The handlebars required by the rear cyclist necessitates an innovative base connected to the bicycle frame located behind the front cyclist seat collar.

A locking mechanism on the handlebar coupler allows deployment of handlebars from retracted, to the riding position.