Sealing Lip Collar Gap for Piston Stability in Mechanical Tone Generators

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Solution Overview

Problem

Existing mechanical sound-generating devices for dolls and toys face issues with piston tilting and air leakage due to limited seal flexibility and mass distribution, leading to suboptimal sound generation, especially during rapid movements.

Innovation Solution

A mechanical sound-generating device featuring a profiled hollow body with a piston and a sliding insert that includes a ceramic material, a weight plate, and a sealing lip with a collar gap, which creates a labyrinth seal to prevent air leakage and ensure optimal sealing without hindering piston movement, allowing for adjustable air flow and tone generation through gravity or acceleration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a seal with limited flexural rigidity is used to prevent air leakage, then sealing is improved, but the seal tends to deviate in the direction of the upper side of the hollow-cylindrical body, causing undesired air passage and negatively influencing sound generation

Engineering Contradiction:
Improvesealing effectivenessVSAvoidseal position stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent employs a flexible sealing lip made of elastomeric material that can deform to maintain contact with the cylinder wall. The sealing lip is designed with specific geometric features including a collar-shaped cross-section with a collar gap oriented towards the closed end, allowing it to flex and conform to the wall surface while preventing air leakage, thus resolving the contradiction between sealing effectiveness and position stability.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention introduces a collar gap in the sealing lip that is oriented in a specific direction (towards the closed end of the cylinder). This directional feature creates an air pressure differential that generates a stabilizing force on the sealing lip, counteracting the tendency to deviate upward. By utilizing pressure distribution in the radial dimension, the seal maintains both effective sealing and positional stability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If guide ribs are distributed around the circumference to support the piston, then piston stability is improved, but the piston may tilt in the hollow-cylindrical body with impairment of the desired tone generation

Engineering Contradiction:
Improvepiston support stabilityVSAvoidpiston movement smoothness
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent removes the traditional guide ribs from the piston design and replaces them with a sliding insert that moves within the hollow-cylindrical body. This extraction of the guiding function from the piston itself and relocation to a dedicated sliding component eliminates the tilting issue while maintaining support stability, as the sliding insert can move freely without the constraint of circumferential guide ribs.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The sliding insert acts as an intermediary component between the piston and the hollow-cylindrical body. It provides the necessary support and guidance function while allowing smooth movement, mediating between the need for stability and the need for ease of operation. The sliding insert absorbs the guiding function without causing piston tilting.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the piston is relatively heavy to achieve sufficient air throughput for tone generation, then sound generation is improved, but the piston mass increases device complexity and manufacturing cost

Engineering Contradiction:
Improveair throughput for sound generationVSAvoidpiston mass and weight bodies
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent changes the material parameter of the piston from traditional heavy materials to ceramic material, which provides sufficient mass for air throughput while having favorable density and acoustic properties. Additionally, the sealing lip geometry parameters are optimized to improve sealing effectiveness, allowing for more efficient air displacement with reduced piston mass, thus achieving sound generation without excessive weight.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If the seal is arranged on the piston circumference to seal against the cylinder wall, then air leakage prevention is improved, but the seal tightness is limited during rapid downward movement of the piston

Engineering Contradiction:
Improveair leakage preventionVSAvoidpiston movement speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent transforms the static seal arrangement into a dynamic sealing system. The sliding insert is designed to move with the piston and maintain sealing contact through its collar-shaped structure with a collar gap. During rapid downward movement, the dynamic configuration allows the seal to adapt to changing pressure conditions, maintaining tightness throughout the motion cycle rather than being limited to static or slow-moving conditions.

Inventive Principle:
Principle #15Dynamics

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

The solution provides reliable sound generation with improved sealing and adjustable tone sequences, eliminating the risk of piston tilting and air leakage, while allowing for variable tone length and pitch control through weight selection and structural modifications.

Implementation Method 1

the piston causes an air flow rate in the flow passage with the result of tone generation by movement, in particular by sliding down in the profile hollow body due to gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 2

A tone generator arranged in the piston head causes the air displaced during the movement of the piston to oscillate, which can be heard as an acoustic event

Methodology Applied
Scientific EffectSound generation by air oscillation: Sound

Data Source

PatentEP2644239B1Mechanical tone generation device
Publication Date: 2014.06.11 KARL TIERSTIMMEN U SPIELWAREN
  • EP2644239B1 patent drawingFigure 1
  • EP2644239B1 patent drawingFigure 2
  • EP2644239B1 patent drawingFigure 3~4

AI summary

The device has an end closed profile hollow portion (9) whose inner side is provided with a piston (7). The front end of piston is provided with a flow passage (15) in which a tongue-shaped sound producing device (5) is provided. The piston slides in the hollow portion for reducing the air flow in the flow passage, and a seal lip (10) is located in the peripheral surface of the hollow portion. The seal lip has a collar portion with collar gap that is oriented towards the closed end of the hollow portion. A sliding insert unit holds a weight plate.