Spring-Biased Cable Tensioner With Ratchet for Window Assemblies
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Solution Overview
Problem
Existing cable tensioners in power-operated window systems increase packaging complexity, length, and reduce design flexibility, while also increasing noise and reducing the efficiency of the reset function of the latch.
Innovation Solution
A cable tensioner with a spring-biased tension lever and ratchet arrangement that maintains constant tension on the cable by allowing pivotal movement between two angles, utilizing a unidirectional clutch to prevent reverse movement, thereby eliminating the need for an additional cable conduit and reducing overall length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an in-line cable tensioner is disposed between cable ends, then cable tension is maintained, but the overall cable length increases and packaging complexity increases
Solution Approach 1:
The patent extracts the cable tensioner from the in-line configuration and relocates it to the door carrier assembly. The tensioner is now mounted separately on the carrier rather than being embedded within the cable run, which reduces packaging complexity while maintaining tensioning functionality through the carrier-mounted configuration
Solution Approach 2:
The patent transitions from a linear in-line tensioner arrangement to a carrier-mounted tensioner that operates in a different spatial dimension. The tensioner is positioned on the carrier body with its arm extending radially, changing the geometric arrangement from collinear to radial/offset, thereby reducing overall cable length and packaging complexity
2Reliability
If an in-line cable tensioner is used, then cable tension is maintained, but the cable length increases
Solution Approach 1:
By extracting the tensioner from the cable run and mounting it on the carrier, the patent eliminates the need for the cable to pass through the tensioner body, thereby reducing the overall cable length required while maintaining the tensioning function through the carrier-mounted configuration
3Reliability
If a spring-biased cam mechanism is used, then constant cable tension is maintained, but device complexity increases
Solution Approach 1:
The spring-biased cam mechanism is designed to automatically maintain constant cable tension through self-adjusting action. The spring continuously biases the cam arm against the cable, and the cam profile automatically compensates for cable wear and elongation without requiring external control systems, thereby achieving reliable constant tension with relatively simple mechanism
Solution Approach 2:
The patent uses a cam profile with varying radius to change the geometric parameter of the arm-cable contact point. As the cam rotates, the changing radius maintains constant force on the cable despite variations in arm position, achieving constant tension through geometric parameter variation rather than complex control mechanisms
4Reliability
If a unidirectional clutch with ratchet teeth is implemented, then reverse movement is prevented, but manufacturing complexity increases
Solution Approach 1:
The unidirectional clutch is extracted from the cable tensioner body and integrated into the carrier-mounted assembly. The ratchet teeth are formed on the cam or associated with the carrier mounting, separating the clutch function from the tensioning mechanism and simplifying manufacturing of individual components while maintaining reliable unidirectional control
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 provides efficient, accurate, and repeatable cable tensioning with reduced noise and improved design flexibility, maintaining constant tension over the cable's lifespan without adding to its length, thus enhancing the functionality and manufacturing efficiency of vehicle door assemblies.
Implementation Method 1
a cam biasing member (e.g., a spiral torsion spring) imparts a bias on the cam to maintain the cam in constant contact with the cable
Implementation Method 2
The pawl is biased into engagement with the ratchet teeth by a pawl biasing member
Data Source
AI summary
A cable tensioner for a window assembly of a motor vehicle closure panel has a baseplate supporting a tension lever for pivotal movement between a first position, whereat tension lever imparts a first tension in a cable, and a second position, whereat tension lever imparts a second tension in the cable, the second tension being substantially the same as the first tension. A ratcheting arrangement prevents tension lever from returning toward the first tension position. Tension lever is biased toward the first position by a biasing member. Biasing member has a first end operably fixed to baseplate and a second end arranged in biased engagement with tension lever, wherein biasing member is under preload to maintain tension lever in constant engagement with cable.