Transmission for bicycles

• US 4,900,046 A
• Filed: 10/06/1988
• Issued: 02/13/1990
• Est. Priority Date: 10/06/1987
• Status: Expired due to Fees

• Current Assignee: Inaki Aranceta-Angoitia
• Original Assignee: Inaki Aranceta-Angoitia
• Inventors: Aranceta-Angoitia, Inaki
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US07/254,408
• Time in Patent Office: 495 Days
• Field of Search: 280/260, 280/259, 74/750 B, 74/740
• US Class Current: 280/260
• CPC Class Codes: B62M 17/00 Transmissions characterised by use of rotary shaft, e.g. cardan shaft

Abstract

A transmission for bicycles, which substitutes the conventional chain transmission, and which comprises a rimcarrier plate connected to the pedal shaft of the bicycle. A plurality of concentric rings or rims engage with respective pinions mounted with freedom of rotation on a tubular transmission shaft. Within the transmission shaft is positioned a sliding element provided with a diametrical arm, which allows one of the pinions to be blocked at will with respect to the transmission shaft. One guiding rims-pinions group is complemented by a second similar guided rims-pinions group, at the other end of the shaft. The other group of rims and pinions may be selected by an identical arrangement in which a second guided rimcarrier plate transmits the movement through a multiplying planet assembly and ratchet pawls to the shaft of an outlet planetary pinion which is engaged with an engaging track provided on the inner side of the rim of the rear wheel.

Claims

1. Transmission for a bicycle having a nucleus assembly supporting a pedal shaft and a chassis connecting said pedal shaft to a rear wheel of the bicycle, the transmission comprising a first rimcarrier plate rigidly connected to the pedal shaft of the bicycle, a first set of concentric guiding rims fixed to said rimcarrier plate, a drive shaft positioned in said chassis, a first set of pinions permanently engaging said rims and mounted with freedom of rotation on said drive shaft which is radially extended from the pedal shaft to the rear wheel of the bicycle, said drive shaft being a hollow transmission shaft, first means positioned in said hollow transmission shaft for selectively connecting each one of said pinions to said transmission shaft, second selecting means provided on the other end of said transmission shaft, a second rimcarrier plate mounted with freedom of rotation on an additional shaft rigidly connected to the chassis and extending perpendicular to said transmission shaft, a second set of guiding rims rigidly connected to said second rimcarrier plate, a second set of pinions permanently engaging said respective rims of said second set, a multiplying planet assembly including said second rimcarrier plate and pawls provided thereon, said additional shaft having thereon an outlet pinion which plays on an engaging tack of said rear wheel, and said second selecting means selectively connecting one of said pinions of said second set to said transmission shaft and via said second rimcarrier plate, said multiplying planet assembly and said pawls transmitting a movement of said transmission shaft to said additional shaft and thereby to said outlet pinion, said chassis serving as one of the two arms of a fork connecting the rear wheel to said nucleus.

2. Transmission for a bicycle in accordance with claim 1, wherein each of said first and second selecting means comprises a control knob, a transmission rod longitudinally displaceable within the hollow transmission shaft by said control knob, and a radially extended arm rigidly connected to said rod and projecting externally from said transmission shaft through wide apertures of said transmission shaft and which may adopt a plurality of uncoupling and coupling positions for each of the pinions of the respective set, each of said control knobs being tiltable to effect a longitudinal displacement of the respective transmission rod and consequently cause a change in position of the respective arm to be engaged in a selected one of the pinions of the respective set to select one of multiple pre-established positions corresponding to the number of pinions of the corresponding set.