Wiper Blade Lever with Fall-Off Preventing Protrusion

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Solution Overview

Problem

In cold climate conditions, wiper blades may stick to the windshield, causing leaf spring members to fall out of accommodating grooves due to excessive deformation between retaining hooks, especially when the interval between hooks is large.

Innovation Solution

A wiper blade design featuring a lever member with first and second retaining hooks and a fall-off preventing protrusion between them, which projects towards the windshield to prevent the leaf spring member from falling out by receiving the blade rubber during movement from the wiper stop to the reversal position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the interval between retaining hooks is increased to reduce material usage and weight, then the lever member becomes lighter and uses less material, but the leaf spring member may fall out of the accommodating groove when the blade rubber deforms significantly

Engineering Contradiction:

Improveweight of lever memberVSAvoidretention of leaf spring member

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The lever member is segmented into multiple functional zones: first and second retaining hooks for primary retention, and intermediate fall-off preventing protrusions for secondary retention. This segmentation allows the hooks to be spaced farther apart (reducing material) while intermediate protrusions prevent leaf spring loss during blade rubber deformation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Fall-off preventing protrusions act as intermediary elements between the retaining hooks. These protrusions provide intermediate support points that prevent the leaf spring member from falling out when the blade rubber deforms, without requiring the main retaining hooks to be closely spaced.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the blade rubber is allowed to deform freely between retaining hooks, then the wiper blade can adapt to surface irregularities, but the leaf spring member may fall out of the accommodating groove

Engineering Contradiction:

Improveadaptation to surface irregularitiesVSAvoidretention of leaf spring member

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

Different regions of the lever member have different functional qualities: retaining hooks provide strong retention at endpoints, while intermediate fall-off preventing protrusions provide lighter guidance. This local differentiation allows blade rubber deformation for surface adaptation while preventing leaf spring loss at critical locations.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The fall-off preventing protrusions serve as intermediary structures that guide the blade rubber and leaf spring member during deformation, allowing the blade to conform to surfaces while preventing catastrophic failure of leaf spring retention.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If retaining hooks are positioned far apart to reduce material, then manufacturing is simpler and material cost is lower, but the leaf spring member is more likely to fall out during operation

Engineering Contradiction:

Improvesimplicity of lever member structureVSAvoidprevention of leaf spring member fall-off

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The retention function is segmented between primary retaining hooks and secondary fall-off preventing protrusions. This segmentation maintains reliability by providing multiple retention points while keeping the overall structure simple and easy to manufacture as an integrated lever member.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The fall-off preventing protrusions are merged into the lever member as an integrated structure, combining the retention function with the lever member itself rather than using separate components, thereby maintaining ease of manufacture while improving reliability.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8528156B2Wiper blade

Publication Date: 2013.09.10 DENSO CORP

AI summary

A wiper blade for connection to a wiper arm for wiping a surface to be wiped while swinging to-and-fro between a wiper stop position and a reversal position. The wiper blade includes a lever member configured to be coupled to the wiper arm, and a blade rubber retained by the lever member. The lever member includes first and second retaining hooks projecting toward the surface to be wiped and arranged at an interval in the longitudinal direction of the lever member. The blade rubber includes accommodating grooves, which are open toward a wiping direction. A leaf spring member is mounted in each accommodating groove. The first and second retaining hooks retain the blade rubber while preventing the leaf spring members from falling out of the accommodating grooves. The lever member further includes fall-off preventing protrusions arranged between the first and second retaining hooks in the longitudinal direction of the lever member. The fall-off preventing protrusions project toward the surface to be wiped. The fall-off preventing protrusions are arranged on the rear side of the blade rubber with respect to a direction in which the blade rubber moves from the wiper stop position toward the reversal position. The fall-off preventing protrusions permit movement of the blade rubber in the direction perpendicular to the surface. When the blade rubber moves from the wiper stop position toward the reversal position, the fall-off preventing protrusions receive the blade rubber so as to prevent the leaf spring members from falling out of the accommodating grooves.