Parallel Crank Applicator with Nested Bars

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Solution Overview

Problem

Existing applicators for extruding fluid materials, such as those used in dentistry, face challenges with operability due to changing lever angles and the risk of hand sandwiching between crank bars, leading to difficulties in gripping and proper force transmission.

Innovation Solution

An applicator design featuring a parallel crank mechanism with a first and second crank bar, where the second crank bar covers the side surfaces of the first crank bar in a sandwiching manner, preventing hand sandwiching and maintaining a consistent lever angle, enhancing operability and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a lever is coupled to a main body via a parallel crank that includes a pair of crank bars, then the angle of the lever with respect to the main body remains constant, but the distance between the crank bars changes when they swing, creating a risk of hand sandwiching

Engineering Contradiction:

Improvelever angle stabilityVSAvoidhand sandwiching risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The first crank bar is nested within the second crank bar, which covers at least a part of side surfaces of the first crank bar in a sandwiching manner. This nesting configuration maintains the parallel crank mechanism's angle stability while eliminating the gap between crank bars that causes hand sandwiching risk.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The parallel crank is segmented into two distinct crank bars (first and second) with specific functional divisions: the first crank bar serves as the core functional element, while the second crank bar serves as a protective covering structure. This segmentation allows each component to fulfill its specific role in resolving the technical contradiction.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If the lever angle changes while extruding fluid material, then the extrusion mechanism can be simpler, but the user has difficulty gripping the lever and main body, and fails to properly extrude the fluid material

Engineering Contradiction:

Improvemechanism simplicityVSAvoidgripping difficulty

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The parallel crank mechanism provides dynamic angle stabilization, where the crank bars swing in a coordinated manner to maintain a constant lever angle relative to the main body throughout the extrusion cycle. This dynamic stability ensures consistent user grip and force transmission while preserving the simplicity of the extrusion mechanism.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10913090B2Applicator

Publication Date: 2021.02.09 GC CORP

AI summary

An applicator (1) includes a main body (10), a parallel crank (40), and a lever (50). The parallel crank (40) includes a first crank bar (41) and a second crank bar (42). The first crank bar (41) and the second crank bar (42) each have one end portion swingably coupled to the main body (10). To the lever (50), another end portion of the first crank bar (41) and another end portion of the second crank bar (42) are each swingably coupled. The second crank bar (42) covers at least a part of side surfaces on both sides of the first crank bar (41) in an axial direction of a pin (43) as a rotation axis of the first crank bar (41) with respect to the main body (10) in a sandwiching manner.