Derailleur

A derailleur for moving a chain to different sized sprockets arranged between a range of sizes increasing from smallest to largest in a sprocket nest, the derailleur comprises:

• an angled pivot guide feed arm supporting a chain guide roller for directing the chain onto one of multiple sprockets within the sprocket nest,
• wherein the angled pivot guide feed arm is rotatably mounted over pivot end on a single angular pivot pin fixed on an inclined surface attached to the frame, the inclined surface being oriented at an angle equal to a tangent slope of the sprocket nest as measured by a straight line formed between the largest sprocket and the smallest sprocket and when the angled pivot guide feed arm pivot end rotates about the pivot pin, an opposite upper chain guide end supporting the chain guide roller of the pivot guide feed arm traces a planar arcuate path along a sweep angle set and controlled by the rotation about said singular angular pivot pin;
• a projection about or near the pivot end, wherein coils of a tension spring rest on the projection and prevent or limit the tension spring coils from reaching the center of rotation and the tension spring biases both the angled pivot guide feed arm and a chain slack take up idler arm having a chain take up roller and a pair of take-up frame sides, the tension spring being connected to the angled pivotal guide feed arm and the chain slack take-up idler arm, both the guide roller and the chain take-up rollers being held between the take up frame sides of the chain slack take-up idler arm;
• and
• wherein when the chain slack take-up idler arm is moved centered on a middle sprocket the chain guide roller and the chain take up roller are both aligned parallel and in the same plane with the middle sprocket of the sprocket nest wherein the chain slack take-up idler arm when moved from alignment with the middle sprocket is canted on an angle at either extremes of the smallest and largest sprockets wherein the chain guide roller and chain take-up roller are not aligned parallel and in the same plane relative to the respective smallest or largest sprocket creating a twist in the chain which is straightened out by a movement of the guide roller and chain take-up roller by utilizing a gap or clearance between the take-up frame sides of the chain slack idler arm.

A derailleur for moving a chain to different sized sprockets arranged between a range of sizes increasing from smallest to largest in a sprocket nest, the derailleur comprises:

• an angled pivot guide feed arm bent supporting a chain guide roller for directing the chain onto one of multiple sprockets within the sprocket nest,
• wherein the angled pivot guide feed arm is rotatably mounted over pivot end on a single angular pivot pin fixed on a frame or on an inclined surface attached to the frame, the inclined surface being oriented at an angle equal to the tangent slope of the sprocket nest as measured by a straight line formed between the largest sprocket and the smallest sprocket and when the angled pivot guide feed arm pivot end rotates about the pivot pin, an opposite upper chain guide end supporting the chain guide roller of the pivot guide feed arm traces a fixed planar arcuate path along a sweep angle set and controlled by the rotation about said singular angular pivot pin;
• a single tension spring biasing the pivot guide feed arm, the tension spring being connected to the twisted pivot guide feed arm at or near the pivot end and to a chain slack take-up idler arm having a chain take up roller;
• a lancing segment of sheet metal adjacent a hub or pivot to support the tension spring smoothly against the side coils of the spring;
• and
• wherein when the chain slack take-up idler arm is moved centered on a middle sprocket the chain guide roller and the chain take up roller are both aligned parallel and in the same plane with the middle sprocket of the sprocket nest wherein the chain slack take-up idler arm when moved from alignment with the middle sprocket is canted on an angle at either extremes of the smallest and largest sprockets wherein the chain guide roller and chain take-up roller are not aligned parallel and in the same plane relative to the respective smallest or largest sprocket creating a twist in the chain which is straightened out by the movement of the guide roller and chain take-up roller by utilizing a gap or clearance between the take-up frame sides of the chain slack idler arm.