Push-up Device Cam Engagement Mechanism

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Solution Overview

Problem

Conventional push-up devices for fuel lids experience malfunctions due to friction and torsion issues during lock-and-unlock movements, leading to a point where the cam becomes free.

Innovation Solution

A push-up device design featuring a cam portion, rotor, slide groove, engagement projection, lock groove, spring, and sleeve that restricts rod movement in the sliding direction, ensuring the cam remains engaged and preventing free sliding, thereby eliminating malfunctions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the cam is allowed to rotate freely during lock-and-unlock movement, then the device can achieve simple operation, but the cam becomes free at certain points causing malfunction due to friction and torsion

Engineering Contradiction:
Improvelock-and-unlock movementVSAvoidcam engagement stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces a mediator element (the engagement projection on the rotor interacting with the cam groove on the rod) that ensures continuous constraint of the cam during rotation. This intermediary mechanism prevents the cam from becoming free while still allowing the lock-and-unlock movement to proceed smoothly, resolving the contradiction between ease of operation and reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates an equipotential constraint system where the engagement projection and cam groove maintain constant contact throughout the rotation cycle. This ensures that the cam remains constrained at all positions during lock-and-unlock movement, eliminating the free point that causes malfunction while maintaining smooth operation.

Inventive Principle:
Principle #12Equipotentiality

2Device complexity

If the rod is allowed to slide freely in the sliding direction, then the device achieves simple structure, but the cam becomes disengaged causing malfunction

Engineering Contradiction:
Improverod structureVSAvoidcam engagement
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The engagement projection acts as an intermediary that connects the rod's sliding motion to the cam's rotational motion. This intermediary ensures that as the rod slides, the cam remains properly engaged and constrained, preventing disengagement while maintaining relatively simple rod structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Duration of action of moving object

If friction and torsion are present during cam rotation, then the device can achieve continuous motion, but these forces cause malfunction when the cam becomes free

Engineering Contradiction:
Improvecontinuous motionVSAvoidoperation stability
Core Design Contradiction:
Duration of action of moving objectVSReliability

Solution Approach 1:

The engagement projection and cam groove form an intermediary constraint system that maintains continuous contact during motion. This intermediary mechanism ensures that friction and torsion forces are continuously distributed and managed throughout the rotation, preventing the cam from becoming free and eliminating the malfunctions that would otherwise occur.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively prevents the cam from becoming free, ensuring reliable operation by maintaining engagement between the stationary-side cam and movable-side cam, thus preventing malfunctions during lock-and-unlock movements.

Implementation Method 1

a spring inserted to pass through the lower-side rod portion, elastically shrunk inside the case for urging the rotor toward the cam portion

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2447102B1Push-up device
Publication Date: 2014.04.23 NIFCO INC
  • EP2447102B1 patent drawingFigure 1
  • EP2447102B1 patent drawingFigure 2
  • EP2447102B1 patent drawingFigure 3

AI summary

A lock device includes a cam portion including a stationary-side cam; a rotor including a movable-side cam; a slide groove; a slide projection; an engagement projection; and a lock groove, in which the movable-side cam is disengaged from the stationary-side cam, so that the rotor rotates so as to allow the engagement projection that has been fitted in the lock portion to disengage from the lock portion. The urging device includes a spring, and a sleeve inserted to pass through a lower-side rod portion, positioned between the rotor and the spring, and also restricting a movement of the rod in a sliding direction in a lock position of the lock device (for example, a lock groove and an engagement projection, and the like).