Locking Sleeve Chuck to Prevent Inertial Over-Tightening
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Solution Overview
Problem
Conventional chucks for power drivers often experience unexpected over-tightening due to inertial forces and vibrations, making it difficult to loosen the jaws once they lock up.
Innovation Solution
The chuck design incorporates a sleeve locking mechanism that locks the sleeve in a fixed position relative to the nut, preventing inertial forces from causing over-tightening. This is achieved through a nut race with a lock pawl and a click pawl that engage with teeth on the body race, allowing the sleeve to transition between locked, unlocked, and tightening modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the nut is allowed to rotate freely to adjust jaw position, then the chuck can be easily operated to open and close jaws, but inertial forces cause the nut to move unexpectedly leading to over-tightening
Solution Approach 1:
The lock pawl and click pawl are positioned to engage with the teeth on the nut race before inertial forces can cause the nut to move. The spring-loaded pawls are pre-positioned to immediately engage with the teeth, preventing unwanted rotation of the nut due to inertial forces during operation.
Solution Approach 2:
The nut race acts as an intermediary between the nut and the body, providing a controlled interface that allows the nut to rotate only when the pawls are disengaged. The teeth on the nut race work with the pawls to mediate the rotation, permitting controlled adjustment while preventing uncontrolled movement from inertial forces.
2Reliability
If the sleeve is locked in position to prevent over-tightening, then control of clamping force is improved, but the chuck becomes more complex with additional locking components
Solution Approach 1:
The lock pawl and click pawl are integrated into a single nut race component, combining two locking functions into one element. The spring-loaded mechanism is integrated into the nut race, eliminating the need for separate spring assemblies and reducing overall complexity while maintaining the dual function of preventing both loosening and over-tightening.
Solution Approach 2:
The spring-loaded pawls automatically engage and disengage based on the rotational position and forces applied to the nut. The mechanism self-regulates by using the applied forces to control pawl engagement, eliminating the need for external control systems or additional actuators.
3Reliability
If the pawls are spring-loaded to ensure engagement with teeth, then prevention of nut loosening is improved, but the mechanism becomes more complex with additional springs and control members
Solution Approach 1:
The spring-loaded mechanism is integrated directly into the nut race structure, with the springs embedded in recesses within the nut race body. This integration eliminates separate spring housings and control members, reducing complexity while ensuring reliable engagement of both the lock pawl and click pawl with the teeth.
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 solution effectively prevents over-tightening and allows for controlled clamping forces on the working bit, even under conditions of inertial forces and vibrations, thereby improving operational reliability and ease of use.
Implementation Method 1
The nut race may comprise a lock pawl and a click pawl. The body race may comprise a plurality of click teeth having click stopping edges oriented in a first rotational direction and a plurality of lock teeth having lock stopping edges oriented in a second rotational direction.
Implementation Method 2
The sleeve may comprise a sleeve tightening surface that may be configured to engage with the nut tightening surface to tighten the nut when the sleeve is rotated into a tightening position.
Implementation Method 3
The nut may be operably coupled with the jaw threading of the jaws such that rotation of the nut relative to the body moves the jaws relative to the body in the opening or closing direction.
Implementation Method 4
The lock pawl and the click pawl may be spring-loaded. The click pawl and the lock pawl may each include a spring-loaded control member that may be engaged with a corresponding one of the click teeth and the lock teeth.
Data Source
AI summary
A chuck for use with a power driver having a rotatable drive spindle is provided. The chuck may include a sleeve comprising a sleeve tightening surface that may be configured to engage with a nut tightening surface to tighten a nut when the sleeve is rotated into a tightening position. With the sleeve disposed in a sleeve locked position, a click pawl may be engaged with a click stopping edge of one of the plurality of click teeth to inhibit rotation of the nut in a first rotational direction to loosen the nut. A lock pawl may also be engaged with a lock stopping edge of one of the plurality of lock teeth to inhibit rotation of the sleeve in a second rotational direction due to the inertia in the sleeve that would tend to further tighten the nut.