Pin Detent Retention for Rotary Impact Tools
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Solution Overview
Problem
Existing pin detent retention devices in rotary impact tools require deliberate user action for both installation and removal of socket accessory tools, and are susceptible to shear loading, which can shorten their lifespan.
Innovation Solution
A pin detent retention device with a tapered or chamfered surface that automatically compresses into a retracted position during socket installation, eliminating the need for manual tools and reducing shear loading by allowing the socket to bottom out on the anvil rather than the pin detent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pin detent retention device is used to secure socket accessory tools, then secure retention and prevention of accidental removal is achieved, but deliberate user action is required for both installation and removal which reduces ease of operation
Solution Approach 1:
The pin detent is made movable between extended and retracted positions rather than being fixed. The spring biasing member enables the pin to dynamically adjust its position based on operational needs - extended for secure retention during use, retracted for easy installation and removal, thus resolving the contradiction between security and ease of operation
Solution Approach 2:
The spring biasing member is pre-loaded to automatically extend the pin detent into the socket accessory tool after installation, securing it before the user even completes the installation process. This preliminary securing action ensures retention without requiring deliberate user effort to engage the pin
2Reliability
If a pin detent retention device is used to prevent accidental removal, then reliability is improved, but the device is susceptible to shear loading from socket bottoming out which reduces durability
Solution Approach 1:
The spring biasing member acts as an intermediary between the pin detent and the socket accessory tool. It absorbs the impact and shear forces when the socket bottoms out, preventing these forces from being directly transmitted to the pin detent, thus protecting it from shear loading and extending its lifespan while maintaining secure retention
Solution Approach 2:
The spring biasing member is pre-configured to cushion and absorb shear forces before they can damage the pin detent. This beforehand cushioning protects the pin from shear loading during normal operation and accidental impacts, thereby extending its service life while maintaining reliable retention
3Ease of operation
If a ball detent retention device is used for easy installation and removal, then ease of operation is improved, but the socket accessory tool can be removed without deliberate user action which reduces security
Solution Approach 1:
The pin detent is designed to be movable between extended and retracted positions rather than fixed like traditional ball detents. This dynamic capability allows it to provide secure retention when extended during use, while being easily retractable for installation and removal, thus achieving both security and ease of operation that static ball detents cannot provide
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
Enables easy installation of socket accessory tools while ensuring secure retention and reducing pin detent wear, requiring deliberate user action for removal and minimizing shear loading for extended pin life.
Implementation Method 1
A spring biasing member is interposed between the pin detent and the interior end wall structure
Data Source
AI summary
A power tool assembly includes an anvil having an accessory receiving end portion that defines a detent bore. A detent is positioned in the detent bore and movable between a retracted position and an extended position in the detent bore. A biasing member is configured to urge the detent toward the extended position. The detent includes an upper detent portion having a trailing abutment surface, a trailing top surface portion, and a leading top surface portion. When the detent is positioned in the extended position, the trailing abutment surface and the trailing top surface portion are located outside of the detent bore, and the leading top surface portion is located within the detent bore. When the detent is positioned in the retracted position, the trailing abutment surface is located within the detent bore, and the leading top surface portion is located within the detent bore.