Wiper Blade End Cap Guide Profile Elastic Locking
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Solution Overview
Problem
Existing wiper blade designs face challenges in securing end caps effectively during assembly and maintaining functionality while allowing for sufficient flexibility to follow curved vehicle windows, often resulting in material stress and potential dirt and noise issues.
Innovation Solution
The design relocates locking lugs to the side walls further away from the wiper lip, allowing for flexible side walls during assembly and enhanced locking without material overstress, with a decreasing locking lug height for easy assembly and a steep detent drop for increased locking effect, and symmetric recesses in the spring rails for uniformity and reduced part variety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If locking lugs are provided on side walls of guide profiles, then end caps can be securely locked to spring rails, but material stress increases and flexibility is reduced
Solution Approach 1:
The locking lug is inverted from the conventional design where it protrudes outward to engage with the spring rail. Instead, the locking lug is formed as an inward-protruding element on the guide profile that engages with a corresponding recess in the spring rail. This inversion allows the locking mechanism to be integrated into the guide profile structure itself, eliminating the need for separate locking components and reducing material stress while maintaining secure attachment.
Solution Approach 2:
The locking lug is merged with the guide profile as an integrally formed element rather than being a separate component. The guide profile and locking lug form a unified structure where the locking lug protrudes inward from the guide profile's side wall. This merging reduces the total number of parts, simplifies assembly, and distributes stress more evenly across the integrated structure, preventing material overstress while ensuring reliable end cap attachment.
2Reliability
If side walls of guide profiles are made rigid for structural stability, then locking mechanism works reliably, but assembly becomes difficult and flexibility is reduced
Solution Approach 1:
The guide profile is designed with non-uniform wall thickness to achieve different mechanical properties in different regions. The side walls are made thinner in specific areas to provide flexibility and ease of assembly, while other regions maintain sufficient thickness for structural stability and reliable locking. This local variation in quality allows the guide profile to be both easy to assemble and reliably locking without requiring overly rigid construction throughout.
Solution Approach 2:
The guide profile incorporates dynamic characteristics by making the side walls sufficiently thin to allow controlled deformation during assembly. This enables the guide profile to flex slightly during the assembly process, facilitating easier installation of the end cap, while maintaining sufficient rigidity in the locked state to ensure reliable operation. The dynamic design allows the structure to adapt during assembly and then stabilize in its final configuration.
3Object-affected harmful factors
If locking lugs are covered by side walls for protection, then components are protected from dirt and noise, but access for assembly and maintenance is reduced
Solution Approach 1:
The locking lug is extracted from the conventional fully enclosed position and repositioned to protrude inward from the guide profile's side wall. This extraction creates a partially exposed configuration where the locking lug remains accessible from the outside for assembly and maintenance, while still being sufficiently protected by the guide profile structure. The locking lug engages with a recess in the spring rail in a manner that allows external access without requiring disassembly of protective coverings.
4Reliability
If multiple locking mechanisms are provided for secure attachment, then reliability increases, but device complexity increases
Solution Approach 1:
The locking and guiding functions are merged into a single integrated guide profile structure. The guide profile simultaneously provides guidance for the end cap during assembly and locking through the integrally formed locking lug that engages with the spring rail recess. This merging eliminates the need for separate locking mechanisms and guide structures, reducing device complexity while maintaining secure attachment through the unified locking-guiding structure.
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
This solution ensures secure end cap attachment without overstressing materials, maintains flexibility for curved window tracking, and reduces dirt and noise exposure by protecting components, while minimizing part complexity and ensuring consistent performance on both sides of the wiper blade.
Implementation Method 1
the spring rails (28) are pre-bent concavely towards the wiper lip (16), so that in the unloaded state (Fig. 1) only the ends of the wiper blade (10) touch the vehicle window (12)
Implementation Method 2
the side walls closest to the wiper lip are not integrally formed with the end wall, thus being significantly flexible, so that both side walls of a guide profile can yield during assembly
Implementation Method 3
the locking lugs (50, 56) engage in the recesses (30) of the spring rails (28)
Implementation Method 4
Each end cap (36) has at least one molded-on spring tongue (66) that runs essentially parallel to the upper side of the wiper blade head. When the spring tongue pivots, the end-facing flank of the wedge-shaped locking tab rises further, securing the end cap against being pulled off the wiper blade
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
The invention relates to a wiper blade (10) in a flat bar construction, having a rubber-elastic wiper strip (14), in the lateral longitudinal grooves (24) of which two band-shaped spring rails (28) which extend next to each other in a parallel manner and which are bent concavely toward a wiper lip (16) are inserted as support elements which protrude laterally out of the longitudinal grooves (24), and which are held together and attached to each other at the ends thereof by end caps (36) which, on the longitudinal sides thereof, have guide profiles (44) having a u-shaped cross section, the side jaws (46, 48, 60) of which are guided on the portions of the associated spring rail (28), which protrude out of the longitudinal grooves (24), wherein the end caps (36) comprise spring tongues having engagement lugs (50, 62) which engage in recesses (30) of the spring rails (28) and attach same in the assembly direction (52). According to the invention, one of the side jaws (46, 48, 60) of each guide profile (44) is designed to be at least partially elastic and is used as spring tongue, and the engagement lug (50, 62) is molded on the yielding portion of the side jaw (46, 48, 60), wherein the height of said engagement lug decreases in the assembly direction (52) and thus forms a striking bevel (54), while the engagement lug (50, 62) drops off steeply in the opposite direction..