Abstract:
The derailleur cable-collet system is an automatic pedal-rate to wheel-rate adjusting system. Pedal pressure is sensed at the crankshaft hub and electronically compared to pedal-pressure threshold values entered by the rider into an electronic circuit. Pedal velocity is sensed at the front sprocket and electronically compared to velocity threshold values. Shifting decision logic is relayed to feed battery current into solenoid-driven collets that move derailleur cables. An arc-jaw collet moves derailleur cable in one direction, and employs spring-forms for structure and bias. A distribution circuit senses travel limits of derailleur arms and redirects cable travel to another derailleur chain-guiding apparatus. A pedal-position sensor contributes to a pedal shifting time circuit that minimizes chain force during sprocket-shifting actions.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     U.S. Ser. No. 08/181,294, now U.S. Pat. No. 5,407,396. Statement as to rights to inventions made under Federally-sponsored research and development: None 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention utilizes sets of an arc-jaw collet mechanism to move a derailleur cable core of a person-powered vehicle such as a bicycle. The collet takes power from an electric relay whose input includes a battery and electric instruction from pressure and frequency transducers which sense pedal pressure and pedal velocity. Bridge circuits and solenoids link sensing logic with chain shifting apparatus. 
     2. Description of Related Art 
     Riding a bicycle inflicts two physiological problems: 
     1. Heavy pedal forces at a slow-pedal rate delivers less than optimum work from the human body and, if sustained, can induce muscle damage. 
     2. High-velocity pedal travel at light pedal force also delivers less than optimum work from the human body yet accelerates fatigue. 
     Many human-power vehicles provide the rider with a manual control over pedal to wheel ratio. A hand-operated derailleur system is common. 
     However, manual management of levers or grips for as many as eight rear wheel sprockets and three pedalled sprockets does not usually offer optimized transfer of work from the rider into the bicycle. 
     One prior art automatic shifter (U.S. Pat. No. 4,598,920) automatically adjusts the pedal-to-wheel turning ratio for a set of rear wheel sprockets by sensing radial force from the rear wheel turning velocity and adjusting the rear-wheel driving chain with a derailleur guide. As vehicle speed increases, the pedal-to-wheel turning rate is reduced in the ratio steps available from a rear wheel set of sprockets. 
     A shifter described in application Ser. No. 08/181,294, now U.S. Pat. No. 5,407,396 (Chain Shifter) senses mechanical forces within a segment of chain in comparison to a pre-set threshold chain-force, with mechanical apparatus to adjust rear and front derailleur cable actions for an increased pedal-to-wheel turning rate. The shifter also senses a pattern of low chain forces and actuates cams to reduce the pedal-to-wheel turning rate. A pulse converter accepts oscillating signals from force sensors and moves derailleur cables. 
     A problem in shifting a derailleur cable in two directions with a combination of manual and automatic means is to disconnect automatic means from the cable when motion is not being applied. Conventional collets advance a shaft in one direction and then hold the shaft firmly. Such collets are commonly used as tooling for an engine lathe. 
     SUMMARY OF THE INVENTION 
     The derailleur cable collet system moves a derailleur cable by controlled release of stored energy. Sensors of pedal force and pedal velocity provide parameters for comparison with threshold parameter values. When pedal force exceeds a set threshold, stored energy is released into a collet which moves a bicycle derailleur cable to downshift chain travel and induce a higher pedal-to-wheel ratio of easier pedalling. 
     When pedal velocity exceeds a set threshold, combined from multiple inputs, stored energy is released into a second collet whose cable movement will upshift a derailleur apparatus to induce a lower pedal-to-wheel ratio of slower pedalling. 
     A light-weight cable-moving collet responds to breached threshold values to move a cable one direction, and to accommodate other free cable travel. The collet mechanism converts stored energy of forward solenoid pulses into cable movement, and releases resistive contact with the cable by a &#34;broken lever&#34; return action. 
     Sensors for pedal force and velocity are located near the bicycle&#39;s hub, and transducers convert mechanical parameters to computer-circuit inputs. A cable-motion distributor senses limits to automatic shifting of rear derailleur, and directs selected automatic shifting to a front derailleur apparatus. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING: 
     FIG. 1. A Derailleur Cable Collet System 
     FIG. 2. A Bicycle with Cable Collet Components 
     FIG. 3. A Frame-Mounted Pedal Force Transducer 
     FIG. 4. A Pedal Motion Transducer 
     FIG. 5A. An Arc-Jaw Collet with Cable-Core 
     FIG. 5B. An arctravel collet mechanism 
     FIG. 6. A Collet-driving Circuit 
     FIG. 7. An Automatic Shift Module 
     FIG. 8. A Seat-Force Transducer 
     FIG. 9. A Pedal-Force Collet-Driving Algorithm 
     FIG. 10. A Pedal-Velocity Collet-Driving Algorithm 
     FIG. 11. A Work Load Meter Circuit 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     A rear wheel derailleur (FIG. 2-1) is connected to a first cable (FIG. 2--2) whose cable core (FIG. 5-3) passes through a peak downshifting pedal-force collet (FIG. 2-4; 6-4; 9-4) and a pedal velocity collet (FIG. 2-5; 6-5; 10-5). A pedalled sprocket derailleur (FIG. 2-6) shifts sprocket positions using a forward chain-guide (FIG. 2-6.1) and is connected to a second cable (FIG. 2-6.2) which communicates with an upshifting pedal force collet (FIG. 2-6.3; 6-6.3; 9-6.3) and a second pedal velocity collet (FIG. 2-6.4; 6-6.4; 10-6.4). A rider&#39;s force upon a pedal (FIG. 2-7) is sensed in a force transducer (FIG. 3-8; 9-8) as compression between a crank bearing outer surface (FIG. 3-9) and a vertical surface spot (FIG. 3-10) within a bottom frame bracket (FIG. 3-11). A second crank-bearing (FIG. 3-9.1) provides structural freedom to transmit pedal-crank force against the bicycle frame. 
     The force-transducer senses compression force from the coupling of forces through a chain (FIG. 3-12), horizontally reacting to vertical force components of the pedal. A peak force is transmitted into the transducer when the pedal&#39;s crank (FIG. 3-13) is at its horizontal position. 
     The transducer converts a mechanical compression force into an electrical parameter, such as impedance, that is proportional to stress. Current is communicated through the impedance of a pedal-force parameter circuit (FIG. 3-13.1, 6-13.1) to a threshold comparing circuit (FIG. 6-14; 9-14). 
     A rider&#39;s pedalling cadence is sensed by a pedal motion transducer (FIG. 4-15; 10-15) and a velocity parameter circuit (FIG. 4-15.1, 6-15.1). Regularly spaced radial points (FIG. 4-16) are located on an inward-facing surface (FIG. 4-17) of a pedal-driven sprocket set (FIG. 2-18). 
     Passage of radial points across the face of a pulse sensor (FIG. 4-19) alters parameters of a resistive capacitor circuit (FIG. 6-20) to convert rate of point passage to a variable electric output such as current flow. 
     The threshold comparing circuit (FIG. 6-14) converts current rate into impedance parameters that are proportional to velocity. The circuit drives a pedal-speed indicator (FIG. 7-21) and provides input to discriminating switching circuits (FIG. 6-22), such as transistors. 
     Electric parameters from the pedal-force transducer pass through communication lines (FIG. 2-23) to a collet driving circuit (FIG. 6-24) within to vehicle shift module (FIG. 7-25). 
     The module face shows a pedal - force meter (FIG. 7-26 ), a pedal-speed meter (FIG. 7-21), a force option selector (FIG. 7-28), a pedal-speed option selector (FIG. 7-28), a biological range setter (FIG. 7-29), a downshift override switch (button) (FIG. 7-30) and an upshift override switch (button) (FIG. 7-31). 
     Force-threshold setting circuits (FIG. 9-32) compare parameters from pressure transducers (FIG. 9-8) with selected, combined input parameters. A resultant current flow within a bridge (FIG. 6-33) triggers a transistor latch (FIG. 10-34) to actuate and hold a first force relay (FIG. 9-35) from a battery (FIG. 9-36) to drive a pedal-force collet (FIG. 9-4). 
     A combination work load circuit (FIG. 11-37) is an amplifier (FIG. 11-38) having inputs from the pedal force transducer (FIG. 11-8) in force circuit (FIG. 11-39) and the pedal velocity transducer (11-15) in pedal-speed circuit (FIG. 11-40). The amplified signal is averaged in a resistive capacitor to be fed into a &#34;work load&#34; figure-of-merit meter (FIG. 11-41). This meter summarizes a rider&#39;s current net performance. 
     A velocity-threshold setting circuit (FIG. 10-42) responds to speed option settings (FIG. 7-28) and is input to the velocity threshold bridge circuit (FIG. 6-14). The bridge output passes through holding and relay apparatus to relays that drive the wheel upshift collet (FIGS. 6-5; 10-5) or pedal downshift collet (FIGS. 6-6.4; 10-6.4). 
     Each cable-moving collet (FIG. 5A) is attached to a frame (FIG. 2-43) portion of the bike and is connected to a battery (FIG. 2-36) in a power circuit (FIG. 9-44). 
     An arc-travel collet mechanism (FIG. 5A-45) is mounted on the frame through a foundation piece (FIG. 5A-46) that supports a collet-driving solenoid (FIG. 5A-47), an outwardly extended shaft (FIG. 5A-48) and a top horizontal spring segment (FIG. 5A-49) of a spring form. 
     The spring form bends its forward vertical spring arm (FIG. 5A-50) downwardly and bends the arm&#39;s end (FIG. 5A-51) horizontally outward. 
     The outwardly bent end fits into a forward swinging-port bearing (FIG. 5A-52) of a bed (FIG. 5A-53) whose top axial surface (FIG. 5-54) is slanted upwardly toward a forward end, and whose top width surface is depressed toward its center (FIG. 5A-55). The bed surface becomes a bottom jaw (FIG. 5A-56) on which a cable core (FIG. 5A-3) slides. A second bearing (FIG. 5A-57) supports the second end of the bed. 
     A spring-form trapeze (FIG. 5A-58, 5B-58) rotates on the outwardly extended shaft (FIG. 5-48) and extends downward 1/2 way to the top surface level of the cable core as it lies at the bottom jaw bed. 
     A bottom bar (FIG. 5A-59, 5B-59) of the trapeze connects to the solenoid&#39;s energy transfer bar (FIG. 5A-60, 5B-60). Stiff arms (FIG. 5A-61, 5B-61) connect to the ends of a downward-facing top jaw (FIG. 5A-62, 5B-62) and midpoint bearings (FIG. 5A-63, 5B-63) connect the arms to the trapeze bottom bar, and passing the energy transfer bar through the stiff arm to also connect to the bottom bar. The stiff arms of the top jaw extend upwardly beyond the shaft on which the trapeze swings. 
     The cable core passes through the arc-travel collet to lie on the bed of the lower jaw until solenoid action advances the trapeze bar. The bar rotates the stiff arms of the top jaw to bring a top jaw surface (FIG. 5A-64, 5B-64) in contact with a slanted top surface of the cable core. 
     Compression of the cable core against the slanted bed rotates forward spring arm (FIG. 5A-50) and the trapeze to the end of the solenoid&#39;s stroke. 
     Reverse motion of the energy transfer bar (FIG. 5A-60, 5B-60) draws the midbearing of the top jaw to &#34;break&#34; the compressive link of the top jaw and the trapeze, releasing compressive downward pressure against the cable core and releasing the vertical spring arm to return the bed with very low friction against the cable core. 
     A collet driving circuit (FIG. 6-24) draws inputs from a pedal-force parameter circuit (FIG. 6-13.1), a pedal-velocity parameter circuit (FIG. 6-15.1), a seat-force transducer circuit (FIG. 8-66) a derailleur rear-wheel travel-limit circuit (FIG. 6-67), a derailleur pedalled sprocket position circuit (FIG. 6-68), manually-adjusted pedal-force threshold value-setting (switch) circuits, (FIG. 6-27), manually-adjusted velocity threshold value-setting (switch) circuits (FIG. 6-28), and pedal-position memory series switch circuits (FIG. 11-71). 
     The collet-driving circuit draws power from a battery, compares bridge-circuit values, and triggers relays to transmit power to collet-driving solenoids. 
     A bridge circuit (FIG. 6-33) within the pedal-force collet driving circuits compares input parameter values from a transducer circuit and combines parameter values from threshold-setting circuits. When sensed transducer values exceed threshold values, a transistor actuates relays connected to collets that are oriented for pull motion to a rear wheel derailleur system or for push motion to a pedalled sprocket derailleur system. 
     A pedal position shift-timer (FIG. 6-72) locates grouped teeth (FIG. 4-73) on two segments of an inward-facing sprocket-ring (FIG. 4-74) whose radius passes a position sensor (FIG. 11-75). 
     Pedalled rotation of the sprocket passes the teeth across the position sensor to communicate a switching signal into the holding and relay circuit. An optimum readiness for shifting occurs when minimum force is being transferred between the pedal and the wheel. Normally the low force transfer between a rider and pedal occurs when a pedal crank is parallel to a rider&#39;s most-straightened leg. 
     The sensor connects to a holding and relay circuit (FIG. 6-76) that accepts shifting instruction parameters from threshold circuits, and delays powering of relays to collet-driving circuits. 
     A cable-motion distributor (FIG. 6-77) connects a minimum rear arm limit switch (FIG. 9-78) and a maximum rear arm limit switch (FIG. 10-79) to relays. When initial cable motion presses the minimum rear arm limit switch, the distributor circuit stops further solenoid current through a first distributor relay (FIG. 13-80) to terminate movement of the rear derailleur cable (FIG. 2--2), and initiates a solenoid current through a second distributor relay (FIG. 13-81) to move the second cable (FIG. 2-5.1) that upshifts (FIG. 6-6.3) the front derailleur. 
     Similarly, when initial cable motion presses the maximum rear arm limit switch, a third distributor relay (FIG. 10-82) terminates service to the rear derailleur, and initiates a fourth distributor relay (FIG. 10-83) to downshift the front derailleur. 
     A cancelled down-shift movement of the first cable collet converts to an up-shift movement of the second cable collet. Thus a cancelled command to reduce a pedal-to-wheel ratio by shifting the chain to a larger rear wheel sprocket becomes a command to reduce a pedal to wheel ratio by shifting the chain to a smaller front sprocket. 
     A front derailleur position sensor (FIG. 6-84) attaches to the front derailleur cable and communicates with the pedal-force threshold setting portion of the pedal-force bridge (FIG. 6-33).