Detachable Fastening Device with Internal Actuation Pin
Solution Overview
Problem
Existing detachable fastening devices for motor vehicle parts, such as expansion clips, face challenges in releasing the fastening mechanism without external access, particularly in confined spaces like engine compartments with blind hole receptacles, leading to limited usability.
Innovation Solution
A detachable fastening device with a base and clamping arms made from hard-elastic plastic, featuring a pivot joint and a blocking mandrel that allows for internal actuation via an actuating pin or slotted screwdriver to release the clamping arms from their locked position, enabling non-destructive release even without external access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the clamping arms are made accessible from outside for release, then the release operation is simple, but the device cannot be used in blind hole receptacles with limited installation space
Solution Approach 1:
The actuating pin is inserted through the insertion opening in the contact flange to reach and actuate the clamping arms from the inside. This nested arrangement allows the release mechanism to be accessed through the existing insertion opening without requiring external access to the clamping arms themselves, enabling use in blind hole receptacles while maintaining simple release operation
Solution Approach 2:
The actuating pin serves as an intermediary tool that transmits the release force from the accessible insertion opening to the clamping arms located inside the blind hole. This mediator enables the operator to release the clamping arms without direct external access to them, resolving the contradiction between ease of operation and adaptability to confined spaces
2Reliability
If the blocking mandrel is inserted to prevent autonomous opening, then the fastening reliability under vibrational loads is improved, but the release operation becomes more complex
Solution Approach 1:
The actuating pin serves multiple functions: it acts as a blocking mandrel to prevent autonomous opening of the clamping arms during normal operation, and simultaneously serves as the release tool when inserted through the insertion opening. This multi-functionality resolves the contradiction by combining the blocking function with the release mechanism, maintaining both high reliability and simple release operation
Solution Approach 2:
The blocking function and release function are merged into a single mechanism. The actuating pin both blocks the clamping arms from opening autonomously and provides the means for intentional release when inserted. This merging eliminates the need for separate blocking and release mechanisms, maintaining reliability while keeping the release operation simple
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 device ensures secure fastening of motor vehicle parts under vibrational loads while allowing for simple and non-destructive release, enhancing usability by eliminating the need for external access to the clamping arms.
Implementation Method 1
The insertion expansion clip of which in one embodiment all the components are fabricated from a hard-elastic plastic, comprises a base having a contact flange... at least one clamping or expanding arm is formed on or integrally with the contact flange, where two clamping arms or precisely one pair of clamping arms can be provided. The at least one clamping arm is configured to engage or snap into a clamping position in the radial direction for locking after overcoming a radial elastic pre-deformation.
Implementation Method 2
In one embodiment, the clamping arm and the contact flanges are made of one piece wherein the snapping elasticity is achieved at a pivot or hinge joint formed in one piece by means of a cross-section reduction at the transition between the contact flange and the at least one clamping arm.
Data Source
AI summary
A device for detachable fastening of an assembly part on a receptacle, the device including a base having a contact flange, at least one clamping arm formed on the contact flange, which snaps resiliently into a clamping position in a radial latching direction. An axial insertion opening is formed in the contact flange. A mandrel is removably inserted into the insertion opening. The mandrel extends as far as a blocking actuation section in a blocking position accommodated in the insertion opening to limit a displacement of the clamping arm from the clamping position or widen the clamping arm in the latching direction into the clamping position. The clamping arm includes an actuation release section which can be actuated by an actuating pin inserted via the insertion opening to urge the clamping arm resiliently from the clamping position opposite to the latching direction.