Door Latch Actuator Reducing Operation Time via 90-Degree Drive Projections
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Solution Overview
Problem
Conventional door latch actuators require longer operation times to switch between lock and unlock states due to increased rotation angles and motor operation times, and manual operation is hindered by the need for greater force and motion synchronization with the worm wheel and motor.
Innovation Solution
A door latch actuator design featuring a reversible motor, a drive portion with 90-degree spaced locking/unlocking drive and stopping projections, and an actuating member with driven and contact portions, allowing for reduced motor rotation and operation time by utilizing the drive projections to move the actuating member efficiently between lock and unlock positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the pinion diameter is made as small as possible to reduce actuator size and weight, then the actuator becomes smaller and lighter, but the operation time increases and the rotation angle of the worm wheel and pinion increases
Solution Approach 1:
The drive portion is designed to rotate only by a predetermined small angle (e.g., 90 degrees or less) instead of requiring the worm wheel to rotate through a large angle. This dynamic adjustment of the rotation range reduces the overall operation time while maintaining the small pinion diameter configuration, thus resolving the contradiction between compact size and fast operation.
Solution Approach 2:
The drive portion is pre-configured with drive projections positioned to engage the actuating member at optimal points in the rotation cycle. This preliminary positioning allows the actuator to achieve full locking/unlocking functionality with minimal rotation, reducing operation time without requiring a larger pinion diameter.
2Reliability
If the pinion always meshes with the actuating member, then the locking mechanism is maintained, but the manually operating means becomes leaden and requires greater force to operate
Solution Approach 1:
The drive portion is designed to rotate only when motor-driven, achieving a limited predetermined angle. During manual operation, this restricted rotation range allows the actuating member to move freely without being constrained by continuous pinion meshing, reducing the force required for manual operation while maintaining reliable locking when motor-driven.
Solution Approach 2:
The drive mechanism is segmented into motor-driven rotation (full functionality) and manual operation modes (restricted rotation). This segmentation allows the system to maintain reliable locking through motor-driven engagement while enabling easy manual operation through limited rotation, resolving the contradiction between reliability and ease of operation.
3Ease of operation
If three teeth are spaced circumferentially by nearly 120 degrees on the worm wheel, then the lock lever can be actuated, but the rotation angle and operation time increase
Solution Approach 1:
Instead of symmetric three-teeth spacing at 120 degrees, the invention uses asymmetric positioning of drive projections on the drive portion that engages the actuating member at optimized points. This asymmetric configuration reduces the required rotation angle to a predetermined small angle (90 degrees or less), significantly reducing operation time while maintaining effective lock lever actuation.
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 design significantly reduces the operation time and force required for switching the door latch between lock and unlock states, enhancing efficiency and usability with reduced motor rotation and manual operation ease.
Implementation Method 1
a reversible motor (48) that rotates a rotating object (51)
Data Source
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AI summary
To provide a door latch actuator that shortens operation time for switching a door latch device to a lock state and an unlock state. When a drive portion 50 is rotated in one direction, one of locking/unlocking drive projections 501 a comes in contact with an upper driven portion 65b to move an actuating member 52 to a lock position. When the actuating member 52 is moved to the lock position, one of the locking/unlocking drive projections 501 a leaves a recess 65a, and a stopping projection 501 c comes in contact with the actuating member 52 to stop rotation of the drive portion 50. When the drive portion rotates in an opposite direction, the other locking/unlocking drive projection 501 b comes in contact with the lower driven portion 65b, so that the actuating member 52 is moved toward an unlock position. When the actuating member 52 is moved to the unlock position, the other locking/unlocking drive projection 501 b leaves the recess, and the stopping projection 501 d comes in contact with the actuating member 52 thereby stopping rotation of the drive portion.