Bicycle Derailleur Cable Clamping and Anti-Rotation
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Solution Overview
Problem
Existing bicycle derailleurs face installation challenges due to incorrect cable exit points from the frame, leading to misalignment and complex adjustments, affecting gear shifting precision.
Innovation Solution
A bicycle derailleur with a cable-clamping washer and anti-rotation appendage system that locks the control cable on the actuation arm, providing distinct points of traction force application to compensate for misalignment, simplifying installation and ensuring precise gear shifting by defining unequivocal positions for the control cable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control cable exit point from the frame is incorrect, then the derailleur installation becomes complex and requires precise alignment adjustments, but the gear shifting precision deteriorates
Solution Approach 1:
The actuation arm is designed with a movable cable contact point that can be repositioned along the arm's length. This dynamic adjustment capability allows the cable exit point to be optimized after installation, compensating for frame manufacturing variations and eliminating the need for precise pre-alignment during installation.
Solution Approach 2:
The invention changes the parameter of cable contact position on the actuation arm. By providing multiple possible contact points along the arm, the system can adjust this parameter to achieve the correct cable angle and movement ratio, thereby maintaining gear shifting precision regardless of the frame's cable exit point location.
2Device complexity
If the cable exit point is misaligned with the derailleur, then installation complexity increases, but the movement ratio precision deteriorates
Solution Approach 1:
The actuation arm incorporates a movable cable contact point that can be repositioned to optimize the cable angle and leverage arm length. This dynamic adjustment simplifies installation by eliminating alignment constraints while maintaining precise movement ratio through proper selection of the contact point position.
Solution Approach 2:
The derailleur is pre-equipped with an actuation arm designed to accommodate cable contact at various positions. This preliminary design feature allows installers to simply select the appropriate contact point without requiring complex alignment procedures, thereby maintaining movement ratio precision while reducing installation complexity.
3Manufacturing precision
If narrow tolerances are used for derailleur mounting to achieve precise gearshifting, then manufacturing precision improves, but device complexity and adjustment difficulty increase
Solution Approach 1:
The movable cable contact point on the actuation arm transforms the system from a fixed-geometry mechanism requiring narrow mounting tolerances to a dynamically adjustable system. This allows broader mounting tolerances while maintaining gearshifting precision through post-installation adjustment of the cable contact position.
Solution Approach 2:
By enabling adjustment of the cable contact position parameter along the actuation arm, the system compensates for variations in derailleur mounting position. This parameter change capability maintains gearshifting precision without requiring narrow mounting tolerances or complex adjustment procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution allows for quick and simple adjustment of the derailleur to achieve the designed movement ratio, reducing installation complexity and enhancing gear shifting precision by forcing the anti-rotation appendage into specific seats, thereby ensuring correct cable constraint.
Implementation Method 1
an anti-rotation appendage (43) projecting from said cable-clamping washer (40) and configured for being inserted in a holding seat (52) of the actuation arm (20)
Implementation Method 2
a cable-clamping washer (40) configured for being fixedly connected to the actuation arm (20) and configured for locking a control cable (100) on the actuation arm (20)
Implementation Method 3
The positioning mechanism of the chain guide is usually formed by a deformable articulated quadrilateral. Such an articulated quadrilateral comprises a fixed body (first side of the quadrilateral) fixedly connected to a strap for the connection about the seat tube, two connecting rods (inner connecting rod and outer connecting rod, which form another two sides of the quadrilateral) rotatably connected to the fixed body about two respective axes and the body of the chain guide itself (which forms the fourth side and completes the articulated quadrilateral) rotatably connected to each of the two connecting rods about two further respective axes.
Implementation Method 4
The outer connecting rod is hinged at the top to the fixed body about the first of the four axes and extends at the top beyond such an axis with an actuation arm to the end of which the control cable of the derailleur is connected. When the control cable is pulled, the actuation arm is actuated and the outer connecting rod rotates about the first axis.
Data Source
AI summary
A derailleur comprising a chain guide, a fixed body adapted for being fixedly associated with a part of frame of the bicycle, and an actuation arm hinged to the fixed body. A cable-clamping washer constrained to the actuation arm locks a control cable on the actuation arm. A first fastening station and a second fastening station are defined on said actuation arm and configured to fasten the control cable in different positions on the actuation arm. An anti-rotation appendage projecting from the chain-clamping washer is adapted for being inserted in a holding seat of the actuation arm and holding the control cable in at least one of the first and the second fastening stations.