Non-Circular Hydraulic Inlet Port for Fastener Tool Head
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Solution Overview
Problem
Existing fastener installation tools with circular hydraulic inlet ports experience stress and premature failure due to pressure peaks during fastener broaching, limiting their operational life as the force required for installation increases with improved fastener strength.
Innovation Solution
A hydro-pneumatically operated fastener installation tool with a non-circular hydraulic inlet port, such as an oval or elongated slot with radiused ends, is designed to minimize stress on the tool head, maintaining compatibility with existing tools and extending their operational life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circular hydraulic inlet port is used in the tool head, then the tool structure is simple and easy to manufacture, but the stress concentration around the port causes premature failure and limits operational life
Solution Approach 1:
The patent applies asymmetry by changing the inlet port cross-sectional shape from circular to non-circular (oval, rectangular, or slot-shaped). This asymmetric geometry redistributes the stress field around the port, eliminating the stress concentration that occurs at the circular port boundaries under hydraulic pressure. The elongated shape aligns with the principal stress directions, allowing more uniform stress distribution and preventing crack initiation, thereby extending tool head operational life.
2Strength
If the fastener stem requires higher breaking force due to improved fastener strength, then the fastening strength increases, but the pressure peak in the tool head increases causing earlier failure
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the inlet port (cross-sectional shape, orientation, and dimensions) to change the stress distribution parameters under hydraulic pressure. The non-circular shape with specific aspect ratios and orientations transforms the stress field characteristics, reducing peak stresses while maintaining the hydraulic pressure levels needed for high-strength fastener installation.
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 non-circular inlet port design reduces maximum stress on the tool head, enhancing durability and operational life by providing a higher factor of safety compared to tools with circular inlet ports, allowing for increased performance and longevity.
Implementation Method 1
the cross-sectional shape of the hydraulic inlet port is non-circular, such that a cross section of the inlet port has a longitudinal axis and lateral axis, wherein the longitudinal axis is greater than the lateral axis... stress around the hydraulic inlet port in the tool head caused on fastener broaching is minimized
Data Source
AI summary
The present invention provides a hydro-pneumatically operated fastener installation tool (2), including a head (4) having hydraulically driven gripping and pulling means for gripping and pulling the stem of a fastener, thereby to install the fastener, and a hydraulic inlet port (6) provided in the head (4) for supplying hydraulic fluid to a cylinder (8) to drive the gripping and pulling means, wherein the cross-sectional shape of the hydraulic inlet port (6) is non-circular, such that a cross section of the inlet port (6) has a longitudinal axis and lateral axis, wherein the longitudinal axis runs widthways across the tool head (4).