Locking Chuck with Camming Pawl Prevents Tool Loosening
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Solution Overview
Problem
Existing chucks for drills and power drivers lack effective mechanisms to prevent unintentional loosening of tools, particularly when subjected to vibrations or torque changes during operation.
Innovation Solution
A chuck design featuring a cylindrical body with a nose section and tail section, including a rotatable sleeve and locking pawls with a camming surface, which engages an annular array of locking teeth to prevent the nut from rotating in the opening direction, ensuring the tool remains securely gripped.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional keyless chuck is used, then the device can be operated manually or with powered drivers, but the tool may unintentionally loosen during operation due to vibrations or torque changes
Solution Approach 1:
The locking pawl is pre-positioned to engage with the locking teeth on the nut, creating a preliminary mechanical lock that prevents the nut from rotating in the opening direction. This preliminary action ensures the tool cannot loosen before vibrations or torque changes occur
Solution Approach 2:
The locking mechanism applies a counteracting force in the closing direction through the engagement portion compressed between the locking teeth and camming surface. This preliminary anti-action counteracts the loosening forces generated by vibrations or torque changes before they can cause tool detachment
2Force
If a locking mechanism with engagement portion compressed between locking teeth and camming surface is added, then additional force is exerted in the closing direction, but the device complexity increases
Solution Approach 1:
The locking pawl combines multiple functions into a single component: it acts as both a locking element (preventing rotation in opening direction) and a force application element (exerting closing direction force through compression between locking teeth and camming surface). This merging increases holding force without proportionally increasing complexity
Solution Approach 2:
The nut serves multiple purposes: it threads with the jaws to control jaw movement, provides locking teeth for the locking mechanism, and acts as the element that would rotate in the opening direction without the lock. This multi-functionality reduces the need for separate components, limiting complexity increase
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 design effectively prevents unintentional loosening of tools by applying additional force in the closing direction, enhancing the chuck's holding power and reducing the likelihood of tool detachment during use.
Implementation Method 1
a camming surface, which engages an annular array of locking teeth to prevent the nut from rotating in the opening direction
Data Source
AI summary
A chuck includes a body having a nose section with an axial bore and a plurality of passageways formed therein, and a plurality of jaws disposed in the passageways. A nut for driving the jaws is rotatably mounted about the body and a sleeve defining a first recess and a second recess is rotatable with respect to the nut between a first rotational position and a second rotational position. An array of locking teeth is fixed to the body and a pawl member with an engagement portion is non-rotatably fixed to the nut. The engagement portion is received in the second recess and engages the locking teeth when the sleeve is in the second rotational position, the engagement portion being compressed so that an amount of force is exerted on the nut in the closing direction by the engagement portion.