Control Cable Spring Geometry to Prevent Gap Locking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Control cables with clearance between the rod member and guide pipe often experience malfunctions, such as incomplete operation or operation cessation, due to the coil spring entering the gap and becoming locked.
Innovation Solution
The control cable design includes a coil spring with a small-diameter portion that is slidable along the inner cable's outer surface and a large-diameter portion, where the small-diameter portion is positioned to be suppressed by the inner cable, preventing entry into the gap between the rod member and hollow member, ensuring smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a clearance is provided between the rod member and hollow member to enable smooth sliding, then the ease of operation is improved, but the coil spring may enter the gap and become locked causing malfunction
Solution Approach 1:
The coil spring is designed with different diameter portions (small-diameter portion and large-diameter portion) at different locations. The small-diameter portion specifically engages with the inner cable to prevent radial movement, while the large-diameter portion maintains the spring's structural integrity and buffering function. This local differentiation resolves the contradiction by preventing spring entry into the gap without compromising sliding smoothness.
Solution Approach 2:
The inner cable acts as an intermediary element between the rod member and the coil spring. By having the small-diameter portion of the coil spring engage with the inner cable, the system creates a mechanical constraint that prevents the spring from entering the gap, while still allowing the rod member to slide smoothly within the hollow member.
2Reliability
If the coil spring is constrained to prevent entry into the gap, then the reliability is improved, but the structural complexity increases
Solution Approach 1:
Rather than constraining the entire coil spring with complex external structures, the invention applies a localized structural modification by creating different diameter portions only where needed. The small-diameter portion is specifically designed to engage with the inner cable, providing the necessary constraint while keeping the overall structure simple and elegant.
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
This configuration effectively suppresses malfunctions by preventing the coil spring from entering and becoming locked in the gap, ensuring continuous and reliable operation of the control cable.
Implementation Method 1
a coil spring through which the inner cable is inserted and which is placed in the hollow member so as to be expandable and contractible along a slide direction of the rod member
Implementation Method 2
the small-diameter portion is provided in a position where movement of the small-diameter portion in the radial direction is suppressed by the inner cable
Data Source
Figure 1(a)~1(c)
Figure 2(a)~2(c)
Figure 3~4(b)
AI summary
A control cable is provided with a coil spring that has a diameter that allows a wire diameter to enter a gap existing in a radial direction between a hollow member and a rod member having a fixing portion and configured to move inside the hollow member. The coil spring includes a small-diameter portion slidable along an outer peripheral surface of an inner cable, and a large-diameter portion having an inner diameter larger than an inner diameter of the small-diameter portion. The small-diameter portion is provided in a position where movement of the small-diameter portion in the radial direction is suppressed by the inner cable when the one end of the coil spring is pressed by the fixing portion, and thus, the position which entry of the coil spring into the gap can be suppressed.