Coaster brake system for a multi-speed bicycle

Claim 2

In a bicycle with a frame-supported rear hub including a coaster brake and an exposed speed change mechanism comprising a plurality of rear sprocket wheels of different numbers of teeth operatively connected to a frame-supported front driving sprocket by means of a driving chain having upper and lower runs, and a rear shifting mechanism adjacent the rear hub assembly and a lower run tensioning means including a pivotally mounted arm extending away from said hub assembly and torque means associated with said arm to swing the arm and maintain tension on the lower run of the chain, chain tensioning means characterized by and comprising means pivotally mounted on said bicycle frame adjacent to said upper run between the rear hub and the front drive sprocket member, said tensioning means including an elongate arm, means pivotally mounting said arm relative to said frame with said arm having a free end extending toward said driving sprocket, chain engaging portions on said arm free end and engaging said upper chain run, second torque means engaging said frame and effecting pivoting of said tensioning means arm to eliminate slack in the upper run upon reverse rotation of said front drive sprocket and said rear sprocket wheels actuating said coaster brake.

Claim 3

A multi-speed chain and sprocket drive for a bicycle as set forth in claim 1 wherein: a. said upper arm tensioning means having spaced chain engaging portions mounted on said arm; b. said chain engaging portions having generally circular peripheries and axes substantially normal to the plane of the chain.

Claim 4

A multi-speed chain and sprocket drive for a bicycle as set forth in Claim 2 including: a. means rotatably mounting said chain engaging portions on said elongate arm with axes of said portions parallel and spaced longitudinally of said arm, said upper run extending over opposed portions of the peripheries thereof and therebetween in a general S-path; b. the pivotal mounting of the upper run tensioning means arm being adjacent the axis of one of said chain engaging portions whereby said elongate arm and chain engaging portions swing generally in the plane of the chain path.

Claim 5

A multi-speed chain and sprocket drive for a bicycle as set forth in claIm 3 wherein: a. said torque means being a resilient member having portions in relative engagement with the frame and elongate arm to urge the chain engaging portion remote from said pivotal mounting toward the chain and maintain tension therein; b. said chain engaging portions having rims extending radially outwardly of the peripheries thereof to limit relative lateral movement of the chain and chain engaging portions.

Claim 6

A multi-speed chain and sprocket drive for a bicycle as set forth in claim 4 wherein said chain lower run tensioning means includes: a. a second elongate arm having second chain engaging portions rotatably mounted thereon in spaced apart relation whereby said lower run extends over opposed portions of the chain engaging portions and therebetween in a general S-path; b. said second torque means being a resilient member and having end portions in relative engagement with the frame and the elongate arm to urge the second chain engaging portion remote from the respective pivotal mounting toward the chain maintaining tension therein, said torque means of the tensioning means for both upper and lower runs moving the respective tensioning means in relative cooperation to eliminate slack in the drive chain at all times.

Claim 7

A multi-speed chain and sprocket drive for a bicycle as set forth in claim 5 wherein: a. each of said elongate arms of the tensioning means having a free end remote from the respective pivotal mounting and extending generally toward the drive sprocket.

Claim 8

A multi-speed chain and sprocket drive for a bicycle as set forth in claim 4 wherein: a. said elongate arm having spaced parallel portions with the chain engaging portions therebetween; b. said parallel portions having flanges extending radially outwardly adjacent the peripheries of the chain engaging portion engaged by said upper run to resist disengagement of said upper run from the chain engaging portions.

Claim 9

In a bicycle with a frame supported rear hub including a coaster brake and an exposed speed change mechanism comprising a plurality of rear sprocket wheels of different numbers of teeth operatively connected to a frame supported front driving sprocket by a driving chain having upper and lower runs and a rear shifting mechanism adjacent said rear sprocket wheels including: a. a bicycle frame portion having spaced apart members extending and diverging forwardly from the rear hub, said upper run being disposed between said frame members and in a plane substantially parallel to the plane of said frame members; b. an elongate bracket member extending between said frame member and fixed thereto, said bracket member being adjacent said upper run; c. tensioning means including a pair of elongate arms in spaced apart relation, spaced chain engaging wheels between said arms and rotatably mounted thereon with said upper run extending over opposed portions of the wheels and therebetween in a general S-path, means adjacent one of said wheels pivotally mounting said tensioning means arms on said bracket for swinging movement substantially in the plane of the chain runs, said arms extending from said pivotal mounting means toward the front driving sprocket; d. a coil spring having end portions with one engaging said bracket and the other engaging one of said arms and operative to urge said tensioning means to pivot toward said upper run to maintain tension therein; e. a lower run tensioning means pivotally mounted on the rear shifting mechanism adjacent to said chain lower run and rear sprocket wheels, said lower run tensioning means including a second pair of elongate arms in spaced apart relation and having a free end extending away from the rear sprocket wheels, spaced chain engaging portions rotatably mounted between said elongate arms whereby said lower run extends over opposed portions of the chain engaging portions and therebetween in a general S-path; f. torque means having end portions in relative engageMent with the rear shifting mechanism and one of said second pair elongate arms to urge the chain engaging portion remote from the respective pivotal mounting toward the chain lower run maintaining tension therein.

Claim 10

In a bicycle with a frame supported rear hub including a coaster brake and an exposed speed change mechanism comprising a plurality of rear sprocket wheels of different numbers of teeth operatively connected to a frame supported front driving sprocket by a driving chain having upper and lower runs and a rear shifting mechanism adjacent said rear sprocket wheels including: a. a bicycle frame portion having spaced apart members extending and diverging forwardly from the rear hub, said upper run being disposed between said frame members and in a plane substantially parallel to the plane of said frame members; b. an elongate bracket member extending between said frame member and fixed thereto, said bracket member being adjacent said upper run; c. tensioning means including a pair of elongate arms in spaced apart relation, spaced chain engaging wheels between said arms and rotatably mounted thereon with said upper run extending over opposed portions of the wheels and therebetween in a general S-path, means adjacent one of said wheels pivotally mounting said tensioning means arms on said bracket for swinging movement substantially in the plane of the chain runs, said arms extending from said pivotal mounting means toward the front driving sprocket; d. a coil spring having end portions with one engaging said bracket and the other engaging one of said arms and operative to urge said tensioning means to pivot toward said upper run to maintain tension therein; e. a lower run tensioning means pivotally mounted on the rear shifting mechanism adjacent to said chain lower run and rear sprocket wheels, said lower run tensioning means including a second pair of elongate arms in spaced apart relation and having a free end extending away from the rear sprocket wheels, spaced chain engaging portions rotatably mounted between said elongate arms whereby said lower run extends over opposed portions of the chain engaging portions and therebetween in a general S-path; f. torque means having end portions in relative engageMent with the rear shifting mechanism and one of said second pair elongate arms to urge the chain engaging portion remote from the respective pivotal mounting toward the chain lower run maintaining tension therein.