Power Tool Housing Insert for Stable Clamping and Leak Reduction
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Solution Overview
Problem
Pneumatic and hydraulic power tools face issues with creep and stress relaxation in plastic housings, leading to reduced clamping force over time and potential fluid leaks, which are exacerbated by the added weight and size of stress-reducing ribs.
Innovation Solution
An insert made of a material resistant to creep and stress relaxation, such as metal, is coupled to the housing to receive fasteners, distributing the clamping force through components that maintain the necessary pressure, thereby reducing fluid leaks without increasing tool dimensions or weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ribs are added to the housing to distribute stress and prevent creep, then the housing's resistance to creep and stress relaxation is improved, but the tool's weight and dimensions increase
Solution Approach 1:
The housing is segmented into two functional parts: a plastic housing body and a metal insert. The metal insert is placed only in the critical stress zone where the fastener applies clamping force, rather than reinforcing the entire housing. This segmentation allows stress distribution improvement localized to where it's needed most, without adding weight throughout the entire tool.
Solution Approach 2:
The invention applies local quality by using different materials in different locations based on functional requirements. The metal insert provides high strength and creep resistance specifically at the fastener interface where clamping force is applied, while the plastic housing maintains its lightweight properties in non-critical areas. This localized reinforcement solves the contradiction between strength and weight.
2Reliability
If metal components are used for the housing to resist creep, then the clamping force maintenance is improved, but the tool's weight increases
Solution Approach 1:
The housing system is divided into plastic and metal components, each performing specific functions. The metal insert handles the high-stress clamping force application, ensuring reliable fastener retention, while the plastic housing provides structural support and keeps overall weight low. This functional segmentation maintains reliability without full-metal construction.
Solution Approach 2:
The invention uses a composite construction combining plastic and metal materials in a single housing assembly. The metal insert is integrated into the plastic housing, creating a hybrid structure that leverages the high strength and creep resistance of metal where needed, while maintaining the lightweight and cost-effective properties of plastic in other areas.
3Stability of the object's composition
If the housing material is changed to metal, then resistance to creep and stress relaxation is improved, but the tool's dimensions and weight increase
Solution Approach 1:
Rather than converting the entire housing to metal, the invention segments the housing into a plastic body with a metal insert. The metal portion is limited to the specific area where clamping force stability is critical, allowing the housing to gain creep resistance without the penalty of full metal construction weight.
Solution Approach 2:
The metal insert provides localized quality enhancement at the fastener interface, where stable clamping force is most critical. This targeted approach ensures that metal's superior creep resistance is applied only where mechanically necessary, while the rest of the housing remains lightweight plastic.
Data Source
AI summary
Inserts disposed in a housing of a pneumatically or hydraulically powered tool having a motor adapted to rotate a drive lug in either of first and second rotational directions. The insert is composed of a material resistive to creep and/or stress relaxation. The insert contacts fasteners applying a clamping force to the tool and remove the housing from the load path of the clamping force, thereby reducing the possibility of fluid leaks.