Patent ID: 6491597
Filing Date: 2002-12-10
Classification: B62M

Abstract:
A front speed changing device comprising:a base mounted on a bicycle frame; a chain guiding member for guiding a chain to displace between a first position and a second position; a first link rod pivoted at a first end with said base and connected at a second end to said chain guiding member; a second link rod pivoted at a mid-section to said base and connected at a second end with said chain guiding member; a recovery member enabling said chain guiding member to guide said chain to swivel toward said first position; a pull cord capable of resisting a recovery force of said recovery member, so as to enable said chain guiding member to guide said chain to displace horizontally toward said second position; wherein said front speed changing device is characterized by: said second link rod which has an extension end, said first end of said second link rod being located between said extension end and said second end of said second link rod; a driven member pivoted to said base and provided with a protruded portion and a start end; a linking member pivoted at a first end with said extension end of said second link rod, and at a second end with said protruded portion of said driven member; said pull cord being fastened, at one end with said start end of said driven member.