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Title: Variable-leverage brakes for bicycles
Claims: I claim: 1. In combination with a force applying device, a brake assembly for an element rotatably mounted on a frame, comprising a pair of calipers, brake pads fixed to the calipers and engageable with said rotatable element, linkage means separately connected to the calipers for pivotal displacement thereof relative to each other by the force applying device, guide track means connected to said linkage means for slidably guiding movement of one of the calipers, and force transmitting means connecting the force applying device to the linkage means and the other of the calipers for sequentially displacing the calipers relative to the element at different leverage ratios. 2. The combination of claim 1, including lock means responsive to engagement of said one of the calipers with said rotatable element for preventing further displacement of said one of the calipers relative to the guide means. 3. The combination of claim 1, wherein said linkage means includes a pivot member to which the guide means is connected, means pivotally mounting the pivot member about a pivotal axis fixed to the frame, a bell crank element pivotally connected to the pivot member, a link connecting the bell crank element to said one of the calipers, and means pivotally connecting the other of the calipers to the pivot member. 4. The combination of claim 3, wherein said force applying device includes a sheathing and an actuator cable slidable therein, said force transmitting means comprising means connecting the actuator cable to the pivot member, and means pivotally anchoring the sheathing to the bell crank element. 5. The combination of claim 1, wherein said other of the calipers is a first-class lever having relatively short and long arms, the force applying device being connected to one of said arms. 6. The combination of claim 5, including preload means resisting said pivotal displacement of said other of the calipers by the force applying device for initially effecting displacement of said one of the calipers on the guide means in response to force applied to the calipers through the force transmitting means. 7. The combination of claim 1, including preload means resisting said pivotal displacement of said other of the calipers by the force applying device for initially effecting displacement of said one of the calipers on the guide means in response to force applied to the calipers through the force transmitting means. 8. In combination with a force applying device, a brake assembly for an element rotatably mounted on a frame, comprising a pair of calipers, brake pads fixed to the calipers and engageable with said rotatable element, linkage means connected to the calipers for displacement by the force applying device, guide means connected to said linkage means for guiding movement of one of the calipers, force transmitting means connecting the force applying device to the linkage means and the other of the calipers for sequentially displacing the calipers relative to the element at different leverage ratios, and lock means responsive to engagement of said one of the calipers with said rotatable element for preventing further displacement of said one of the calipers relative to the guide means, said linkage means including a pivot member to which the guide means is connected, means pivotally mounting the pivot member about a pivotal axis fixed to the frame, a bell crank element pivotally connected to the pivot member, a link connecting the bell crank element to said one of the calipers, and means pivotally connecting the other of the calipers to the pivot member. 9. The combination of claim 8, wherein said force applying device includes a sheathing and an actuator cable slidable therein, said force transmitting means comprising means connecting the actuator cable to the other of the calipers, and means pivotally anchoring the sheathing to the bell crank element. 10. The combination of claim 9 including preload means biasing the other of the calipers to a limit position relative to the pivot member for preventing displacement of said other of the calipers during an initial stage of brake engagement at a lower one of said different leverage ratios. 11. The combination of claim 10, including abutment means mounted by the pivot member and said other of the calipers for establishing said limit position from which the other of the calipers is displaced at a higher one of the different leverage ratios during a final stage of brake engagement. 12. The combination of claim 8 including preload means biasing the other of the calipers to a limit position relative to the pivot member for preventing displacement of said other of the calipers during an initial stage of brake engagement at a lower one of said different leverage ratios. 13. The combination of claim 12, including abutment means mounted by the lever member and said other of the calipers for establishing said limit position from which the other of the calipers is displaced at a higher one of the different leverage ratios during a final stage of brake engagement. 14. In combination with a force applying device, a brake assembly for an element rotatably mounted on a frame, comprising a pair of calipers, brake pads fixed to the calipers and engageable with said rotatable element, linkage means connected to the calipers for displacement by the force applying device, guide means connected to said linkage means for guiding movement of one of the calipers, force transmitting means connecting the force applying device to the linkage means and the other of the calipers for sequentially displacing the calipers relative to the element at different leverage ratios, said linkage means including a pivot member to which the guide means is connected, means pivotally mounting the pivot member about a pivotal axis fixed to the frame, a bell crank element pivotally connected to the pivot member, a link connecting the bell crank element to said one of the calipers, means pivotally connecting the other of the calipers to the pivot member, said force applying device including a sheathing and an actuator cable slideable therein, said force transmitting means comprising means connecting the actuator cable to the other of the calipers, means pivotally anchoring the sheathing to the bell crank element, and preload means biasing the other of the calipers to a limit position relative to the pivot member for preventing displacement of said other of the calipers during an initial stage of brake engagement at a lower end of said different leverage ratios. 15. The combination of claim 14 including abutment means mounted by the lever member and said other of the calipers for establishing said limit position from which the other of the calipers is displaced at a higher one of the different leverage ratios during a final stage of brake engagement. Other info: Inventors: Armstrong, Allen E. (Lexington, MA, US) Application Number: 602668 Filing Date: 1975-08-07 Publication_date: 1977-03-29 Assignee: Primary Class(es): 188/24.15 188/2D, 188/72.9 Other Classes: US Patent Ref:
Other Refs:
Primary Examiner: Halvosa, George E. A. Assistant Examiner: Attorney: Zalkind & Shuster |
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