Constant Force Device Simplifies Transmission Route

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Solution Overview

Problem

Existing constant force devices in mechanical timepieces experience significant power loss when controlling the rotation of stop wheels and pinions due to complex transmission routes and oscillating mechanisms, which affect the stability and accuracy of timekeeping.

Innovation Solution

A constant force device with a simplified transmission route, featuring a stop wheel and pinion that rotates around a coaxial input and output axle, a stopper that adjusts the rotation progress, and a fixed wheel and pinion for planetary movement, reducing friction and power loss, and incorporating a phase shift regulation mechanism to prevent misalignment and damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cam and fork-shaped portion are used to control the oscillating movement of the second anchor for stopping or resuming rotation of the stop wheel & pinion, then the rotation control function is achieved, but the power loss increases significantly

Engineering Contradiction:

Improverotation control functionVSAvoidpower loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts and eliminates the cam and fork-shaped portion from the mechanism. Instead of using these components to control the oscillating movement of the second anchor, the invention directly engages the stopper with the stop wheel & pinion teeth, removing the intermediate transmission elements that caused power loss while maintaining the rotation control function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the control mechanism by having the stopper directly interact with the stop wheel & pinion teeth rather than using an oscillating anchor controlled by a cam. This reversal of the control approach eliminates the complex transmission route and reduces power loss significantly.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If a complex transmission route is used between the stop wheel & pinion and the output unit, then the rotation control is achieved, but the power loss and friction increase

Engineering Contradiction:

Improverotation controlVSAvoidpower loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent removes the complex intermediate transmission components (cam, fork-shaped portion, oscillating mechanism) from the power transmission route. The stopper directly engages with the stop wheel & pinion teeth, creating a simplified and more efficient transmission path that reduces friction and power loss.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If the stop wheel & pinion rotation is controlled by an oscillating second anchor, then the rotation can be stopped or resumed, but the power loss for controlling rotation increases

Engineering Contradiction:

Improverotation stop and resume functionVSAvoidpower loss

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The patent eliminates the oscillating second anchor mechanism and replaces it with a stopper that directly engages with the stop wheel & pinion teeth. This extraction of the intermediate oscillating mechanism maintains the rotation control functionality while significantly reducing the power loss associated with the complex transmission route.

Inventive Principle:

Principle #2Taking out (Extraction)

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 reduces power loss and stabilizes the output torque, ensuring more accurate timekeeping by simplifying the transmission route and utilizing a stopper to adjust the stop wheel and pinion rotation, while also preventing phase delays and collisions.

Implementation Method 1

an input unit that stores a resilient force in the constant force spring by being rotated around an input axle

Methodology Applied

Scientific EffectElastic potential energy storage: Spring

Implementation Method 2

a stopper that is rotated around the output axle together with the output unit, and that engages with the stop wheel & pinion in response to rotation of the stop wheel & pinion which is rotated around the stop wheel axle body

Methodology Applied

Scientific EffectMechanical engagement: Gear

Data Source

PatentUS9052693B2Constant force device, movement and mechanical timepiece

Publication Date: 2015.06.09 SEIKO WATCH CORP

AI summary

There are provided a constant force device, a movement, and a mechanical timepiece which can decrease a loss of power for controlling rotation of a stop wheel & pinion. A constant force device includes an inner carriage that outputs an output torque by being rotated around a tenon of a first inner rotation body and a tenon of a second inner rotation body, a constant force spring that supplies a rotation force to the inner carriage, an outer carriage that stores a resilient force in the constant force spring by being rotated around a tenon of a first outer rotation body and a tenon of a second outer rotation body, a stop wheel & pinion that is supported to be rotatable around a stop wheel axle body in the outer carriage, and that is rotatable around the tenon of the first outer rotation body and the tenon of the second outer rotation body, and a stopper that is rotated around the tenon of the first inner rotation body and the tenon of the second inner rotation body together with the inner carriage, and that engages with the stop wheel & pinion in response to rotation of the stop wheel & pinion which is rotated around the stop wheel axle body.