Waterproof Keypad Rigid Layer Prevents Pad Deformation
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Solution Overview
Problem
Conventional waterproof keypads with resilient rubber pads face deformation issues due to pressure and torsion, leading to potential gaps and water ingress, which compromises the waterproof effect, typically meeting only the IPX4 standard.
Innovation Solution
Incorporating a rigid layer connected tightly to the resilient pad body, which prevents undesired deformation and ensures even pressure distribution, allowing the waterproofing ring to maintain a stable seal against the housing, using materials like polycarbonate resin for the rigid layer and thermoplastic elastomer or urethane for the resilient pad body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a resilient rubber pad is used for the waterproof keypad, then the keypad can provide sealing flexibility, but the rubber pad deforms easily under pressure or torsion, compromising waterproof performance
Solution Approach 1:
The patent uses a composite structure combining a rigid layer (PC material) and a resilient pad body (TPU material). The rigid layer provides structural stability and resists deformation under pressure or torsion, while the resilient pad body maintains sealing flexibility. This composite approach resolves the contradiction by integrating materials with complementary properties.
Solution Approach 2:
The waterproof keypad is divided into functionally distinct segments: a rigid layer for structural support and a separate resilient pad body for sealing. This segmentation allows each component to optimize its specific function without compromising the other, preventing deformation while maintaining adaptability.
2Strength
If screws are used to secure the waterproof keypad, then the keypad can be firmly attached to the housing, but torsion during screwing causes the rubber pad to twist and deform
Solution Approach 1:
The rigid layer made of PC material provides high structural strength and torsion resistance during screwing, preventing the pad body from twisting. The composite structure allows firm attachment via screws while maintaining pad integrity.
Solution Approach 2:
By separating the structural support function (rigid layer) from the sealing function (pad body), the patent enables the rigid layer to withstand screwing torsion without deforming the pad body, achieving both firm attachment and shape preservation.
3Reliability
If pressure is applied to the rubber pad to ensure sealing, then the waterproofing ring can abut against the housing, but uneven pressure distribution creates gaps that allow water ingress
Solution Approach 1:
The rigid layer acts as a pressure-distributing interface that converts point pressure from the press member into uniform distributed pressure across the pad body. This ensures even pressure distribution while maintaining effective sealing pressure.
Solution Approach 2:
The rigid layer serves as an intermediary between the press member and the pad body, mediating the pressure transmission to achieve uniform pressure distribution. This intermediary structure prevents direct point loading that would cause uneven pressure and gaps.
4Device complexity
If a conventional rubber pad structure is used, then the keypad can be simple in construction, but the waterproof effect only meets IPX4 standard, not IPX7
Solution Approach 1:
The composite structure of rigid layer plus resilient pad body provides enhanced waterproof performance (IPX7) while maintaining relatively simple construction. The clear functional division between layers simplifies manufacturing and assembly.
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
Enhances the waterproof effect to meet the IPX7 standard, preventing water ingress even when submerged, by ensuring the waterproofing ring abuts tightly against the housing, thus preventing short-circuits and damage.
Implementation Method 1
the press member presses against the rigid layer, the pressure provided by the press member can be exerted more evenly upon the resilient pad body via the rigid layer
Implementation Method 2
the waterproofing ring is able to press against the housing tightly and stably for enhancing the waterproof effect
Data Source
AI summary
An electrical device includes a housing, a circuit unit disposed in the housing, a waterproof keypad disposed in the housing at a position above the circuit unit, and a press member. The waterproof keypad includes a rigid layer, a resilient pad body, a waterproofing ring, and a plurality of keys. The press member is connected to the housing and presses against the rigid layer. The waterproofing ring is connected to a bottom face of the resilient pad body, abuts against the housing, and surrounds the circuit unit. A portion of a top face of the resilient pad body is connected immovably to a bottom face of the rigid layer. Another portion of the top face of the resilient pad body is exposed from the rigid layer. The keys are connected to the exposed portion of the top face of the resilient pad body and are exposed from the rigid layer.