Fixing Device Through-Hole Indicator for Spring Posture Checks
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Solution Overview
Problem
It is difficult for workers to verify if the biasing member, which biases the heat sensitive element against the planar heater, is assembled in the correct posture in the fixing device, leading to potential fixing failures.
Innovation Solution
The fixing device incorporates a stay with a through hole and an interlocking portion that allows easy verification of the compression spring's posture, ensuring correct assembly of the biasing member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the biasing member is disposed inside the stay without external visibility, then the structure is compact and simple, but it becomes difficult to verify correct assembly posture
Solution Approach 1:
A protrusion is introduced as an intermediary element that extends from the biasing member through the stay to the external surface. This protrusion serves as a mediator that translates the internal state of the biasing member into an externally visible indicator, allowing workers to verify assembly posture without complicating the overall structure.
Solution Approach 2:
The biasing member itself is modified to include the protrusion, making it self-indicating. The component serves its dual function of providing biasing force while simultaneously indicating its own assembly status through the protrusion that extends outward for visual verification.
2Reliability
If the stay is made solid without through holes, then structural strength is maintained, but the biasing member cannot be visually inspected
Solution Approach 1:
The stay is designed with local quality variation: most of the stay remains solid to maintain structural strength, while a specific localized region contains a through hole that allows the protrusion to extend outward. This localized modification provides inspection capability without compromising the overall structural integrity of the stay.
Solution Approach 2:
The stay is segmented into two functional zones: a main body portion that provides structural support and a through-hole portion that enables visual inspection. This segmentation allows the stay to simultaneously fulfill both structural and inspection functions.
3Ease of manufacture
If no interlocking portion is provided, then the biasing member can be easily installed, but assembly posture cannot be verified
Solution Approach 1:
The protrusion acts as a visual indicator that changes its visibility state based on assembly posture. When correctly assembled, the protrusion extends to a specific position that is visible through the through hole, providing immediate visual feedback about assembly status without requiring additional tools or complex 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
Facilitates easy checking of the compression spring's correct assembly, reducing the likelihood of fixing failures by ensuring proper contact force and position of the thermistor with the planar heater.
Implementation Method 1
uses a planar heater (a resistive heat generator) as a heating device to heat a fixing belt
Implementation Method 2
The biasing member biases the heat sensitive element against the planar heater
Data Source
Figure 1
Figure 2~4
Figure 5A~6
AI summary
A fixing device (20) includes a planar heater (24), a fixing belt (21) heated by the planar heater (24), a pressure rotator (31) pressing one face of the planar heater (24) via the fixing belt (21), a holder (23) holding the planar heater (24), a heat sensitive element (40) facing another face of the planar heater (24), a biasing member (47) biasing the heat sensitive element (40) against the planar heater (24), a stay (30) holding the holder (23) and accommodating the biasing member (47) in the stay (30), and an interlocking portion (41a, 47a, 47b, and 48). The stay (30) has a through hole (30a). The interlocking portion (41a, 47a, 47b, and 48) has a portion in the through hole (30a) and changes a posture according to a change in a posture of the biasing member (47) in the stay (30).