Gravity-Actuated Ball Lock for Writing Instrument Axial Translation
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Solution Overview
Problem
Manual devices with movable parts, such as mechanical pencils, face issues where the secondary part remains mobile during intended operations like erasing, leading to unintended advancement of the writing lead, which is undesirable.
Innovation Solution
A manual device with a blocking mechanism using a ball housed in a chamber, where the ball's position is determined by gravity to either allow or block the axial translation of parts, ensuring the secondary part remains stationary when not intended for use, thus preventing unintended lead advancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the second part is made movable relative to the first part to enable operations like erasing, then the operational versatility is improved, but the risk of inadvertent movement and unintended lead advancement increases
Solution Approach 1:
The locking device transitions between locked and unlocked states dynamically based on the device's orientation. When held horizontally, the ball engages the locking groove to prevent movement. When tilted vertically, gravity causes the ball to disengage, allowing the second part to move for erasing operations. This dynamic state change resolves the contradiction by providing both stability during writing and mobility during erasing.
Solution Approach 2:
The invention changes the gravitational parameter's effect on the locking mechanism based on device orientation. By utilizing gravity's directional influence, the system automatically switches between locked and unlocked states without additional components. This parameter-based control enables the second part to be both secure during writing and movable during erasing, resolving the reliability-versus-versatility contradiction.
2Reliability
If a locking device is added to prevent inadvertent movement of the second part, then the control precision is improved, but the device complexity increases
Solution Approach 1:
The locking device is self-actuating through gravity's influence on the ball. No additional actuators, springs, or complex mechanisms are required—the ball automatically engages or disengages based on the device's orientation. This self-service approach provides reliable locking control while minimizing structural complexity, as the gravity field itself serves as the actuating force.
Solution Approach 2:
The invention extracts the essential locking function into a simple ball-and-groove mechanism, separating it from the main device structure. This extracted minimalistic locking system provides the necessary control precision without adding significant complexity to the overall device, as it uses only a ball, a groove, and the existing gravitational field.
3Reliability
If the locking device uses a ball and chamber mechanism to block translation, then the reliability of preventing inadvertent movement is improved, but the device volume increases
Solution Approach 1:
The ball and chamber are nested within the existing cylindrical structure of the mechanical pencil. The chamber is formed as a cavity within the barrel, and the ball is contained within this space without requiring additional external volume. This nesting approach provides reliable locking functionality while minimizing the increase in device volume, as the locking mechanism is integrated into the existing form factor.
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 effectively prevents the secondary part from moving inadvertently, maintaining the integrity of the writing mechanism and ensuring precise control over the manual device's functions, while maintaining a compact design suitable for most users.
Implementation Method 1
the ball's position is determined by gravity to either allow or block the axial translation of parts
Data Source
Figure 1~3
Figure 4~5
AI summary
A manual device (10) comprising a first portion (12) and a second portion (14), the first portion (12) being at least partially sleeved with the second portion (14) and being movable in translation in an axial direction (X) relative to the second portion (14), the first portion (12) having a first distal end (12A) while the second portion (14) has a second distal end (14A) opposite the first distal end (12A) in the axial direction (X), and an immobilisation device (16) designed to prevent the first portion (12) from moving in translation in the axial direction (X) relative to the second portion (14) only when, considered in the direction of gravity (G), the first distal end (12A) is arranged above the second distal end (14A), the immobilisation device (16) comprising a chamber (16B) and a ball or equivalent (16A), housed in the chamber (16B).