Single-Piece Oscillating Arm for Windscreen Wiper Spring Mounting
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Solution Overview
Problem
Existing windscreen wiper devices require complex machinery and multiple constructional parts for manufacturing and mounting, increasing costs and complexity.
Innovation Solution
A single-piece oscillating arm made from a flat metal sheet with a U-shaped cross-section and a bayonet connection, featuring a partially closed tube with co-axial holes for spring accommodation, reducing the number of parts and manufacturing costs while enhancing rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple constructional parts (wiper rod, holder, mounting head pin) are used to accommodate the spring, then the spring can be properly mounted, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent merges the wiper rod, holder, and mounting head pin into a single integrated oscillating arm component made from one piece of sheet material. The spring accommodation features (lips with holes) are formed directly as integral parts of the oscillating arm, eliminating the need for separate constructional parts while maintaining the spring mounting function.
Solution Approach 2:
The oscillating arm is designed to perform multiple functions simultaneously: it serves as the structural arm, the spring holder, the mounting interface, and the connection point for the wiper blade. The integral design with formed lips and holes provides spring accommodation without requiring additional specialized components.
2Reliability
If multiple constructional parts are used for the oscillating arm, then the spring can be accommodated, but complex machinery and tools are needed for manufacturing and mounting
Solution Approach 1:
The patent combines multiple manufacturing operations into a single sheet metal forming process. The oscillating arm with its integral spring accommodation features (lips and holes) is produced in one piece from sheet material using standard forming techniques, eliminating the need for complex assembly machinery and multiple manufacturing steps required for separate parts.
Solution Approach 2:
The oscillating arm is designed to be self-contained with all spring accommodation features integrated directly into the structure. The lips with holes are formed as integral parts, allowing the component to serve its own mounting function without requiring external holders or separate mounting mechanisms.
3Device complexity
If a single-piece oscillating arm is used, then manufacturing costs and complexity are reduced, but the rigidity may be compromised
Solution Approach 1:
The patent applies local quality by forming specific regions of the oscillating arm with enhanced structural characteristics. The lips with holes are formed with appropriate thickness and geometry to provide localized reinforcement for spring accommodation, while the main body maintains the necessary rigidity. The tube structure with partially closed ends provides structural reinforcement at critical locations.
Solution Approach 2:
The oscillating arm incorporates a tube structure with curved geometry rather than straight rigid sections. The tubular form with partially closed ends provides structural strength and rigidity while maintaining the single-piece construction. The curved geometry of the tube distributes stresses more effectively than straight sections.
Data Source
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AI summary
A windscreen wiper device (1), particularly for automobiles, comprising an elongated wiper blade (2), which can be placed in abutment with a windscreen to be wiped, which windscreen wiper device comprises a connecting device (7) for an oscillating arm (8), wherein said oscillating arm is pivotally connected with its first end to said connecting device and with its second end to a mounting head (18) on a drive shaft (19), and wherein said oscillating arm is provided with a longitudinally extending base (29) and two spaced-apart sidewalls (30, 31) extending outwardly along opposite sides of said base to form a tube having an open face, with the special feature that said oscillating arm is produced integrally from a single sheet material, wherein outboard edges (32, 33) of said sidewalls are folded inwardly towards each other to partially close said open face of said tube.