Elastic Nail Stopper for Pyrotechnic Actuator Piston Locking
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Solution Overview
Problem
Existing pyrotechnic actuators for airbag and pedestrian protection devices face challenges in simplifying the structure for preventing piston movement before and after activation, with known solutions either being complex or inefficient in locking the piston in place.
Innovation Solution
An actuator design featuring a cylindrical stopper with a nail portion made of elastic material that inhibits piston movement before activation by contacting an enlarged diameter portion and prevents backward movement after activation by expanding beyond the cylinder's opening diameter, utilizing a simple and effective mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex locking mechanism with multiple components is used to prevent piston movement before and after activation, then the piston can be reliably fixed, but the device size and weight increase
Solution Approach 1:
The invention combines the pre-activation locking function and post-activation prevention into a single integrated elastic stopper component. The stopper includes a body portion and a nail portion that work together to provide both locking functions, eliminating the need for separate locking mechanisms and reducing overall device weight while maintaining reliability
Solution Approach 2:
The elastic stopper utilizes dynamic deformation properties - it elastically deforms to allow piston movement during activation while maintaining its shape to prevent backward movement afterward. This dynamic behavior enables a single component to perform multiple functions that would otherwise require separate static mechanisms
2Reliability
If multiple locking components are used to secure the piston before and after activation, then the piston can be firmly fixed, but the device structure becomes complicated
Solution Approach 1:
The invention merges the pre-activation locking function and post-activation prevention into a single integrated elastic stopper component. The stopper includes a body portion and a nail portion that work together to provide both locking functions, eliminating the need for separate locking mechanisms and reducing overall device weight while maintaining reliability
Solution Approach 2:
The elastic stopper is designed as a multi-functional component that performs both pre-activation locking and post-activation prevention. The same component adapts its function based on the activation state, providing universal locking capability throughout the actuator's operational cycle
3Weight of stationary object
If a simple locking structure is used to reduce device size and weight, then the overall device becomes more compact, but the piston may not be reliably fixed before and after activation
Solution Approach 1:
The invention changes the material parameter of the stopper to elastic material, which provides both mechanical strength for reliable locking and flexibility for compact design. The elastic properties allow the stopper to deform under load and return to its original shape, ensuring reliable fixation while maintaining a compact structure
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 actuator effectively locks the piston in place before and after activation using a single elastic stopper component, ensuring reliable operation and size/weight reduction in the device.
Implementation Method 1
a nail portion which inwardly projects from the main body portion and is formed of an elastic material
Implementation Method 2
after the activation of the ignition device, the piston is inhibited from moving in a backward direction by causing the nail portion to contact another part of the enlarged diameter portion
Data Source
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AI summary
The present invention provides an actuator including: a cylinder connected to an ignition device; a piston slidably accommodated inside the cylinder, the piston having, in a desired section in the length direction, an enlarged diameter portion in which an outer diameter is enlarged; a cylindrical stopper attached to an inner peripheral surface of the cylinder, the stopper including, a main body portion which is fixed to the inner peripheral surface of the cylinder, and a nail portion which inwardly projects from the main body portion and is formed of an elastic material, wherein before activation of the ignition device, the piston is inhibited from moving in an axial direction by causing the nail portion to contact a part of the enlarged diameter portion, after activation of the ignition device, the piston is inhibited from moving in a backward direction by causing the nail portion to contact another part of the enlarged diameter portion.