Mammography Arm Layout to Reduce Rotational Moment Load

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Solution Overview

Problem

Existing mammography apparatuses face increased rotational moments and load on the drive mechanism due to the disposition of the drive and restriction mechanisms in the arm, leading to potential inefficiencies and mechanical stress.

Innovation Solution

The mammography apparatus is designed with the drive mechanism and restriction mechanism positioned to intersect the center line of the arm, bringing the center of gravity closer to the support shaft, reducing the rotational moment and load on the drive mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the drive mechanism and restriction mechanism are disposed in the arm, then the arm can be equipped with necessary functional components, but the center of gravity becomes biased and the rotational moment around the support shaft increases

Engineering Contradiction:
Improvefunctional components integrationVSAvoidrotational moment
Core Design Contradiction:
Adaptability or versatilityVSForce

Solution Approach 1:

The patent applies counterweight principle by positioning the drive mechanism and restriction mechanism on opposite sides of the arm's center line. This creates a balanced distribution of mass that counteracts the gravitational torque, reducing the net rotational moment around the support shaft while maintaining all necessary functional components in the arm

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Adaptability or versatility

If the drive mechanism and restriction mechanism are disposed in the arm, then the arm can be equipped with necessary functional components, but the load applied to the drive mechanism increases

Engineering Contradiction:
Improvefunctional components integrationVSAvoidload on drive mechanism
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

By strategically positioning the drive mechanism and restriction mechanism on opposite sides of the center line, the patent creates a balanced configuration that reduces the gravitational load on the drive mechanism, allowing the arm to carry necessary functional components with reduced power requirements

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Adaptability or versatility

If the center of gravity is biased away from the support shaft, then the arm can accommodate mechanisms, but the rotational moment increases requiring more complex drive mechanisms

Engineering Contradiction:
Improvemechanism accommodationVSAvoiddrive mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses counterbalancing positioning to offset the center of gravity bias caused by accommodating mechanisms in the arm. This simplifies the drive mechanism requirements by reducing the rotational moment, eliminating the need for complex high-torque drive systems while maintaining full functional capability

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Data Source

PatentEP4331493B1Mammography apparatus
Publication Date: 2026.04.15 FUJIFILM CORP
  • EP4331493B1 patent drawingFigure 1
  • EP4331493B1 patent drawingFigure 2
  • EP4331493B1 patent drawingFigure 3

AI summary

A mammography apparatus includes an arm (21); and a stand (20), the arm is provided with a drive mechanism (40) including a motor (40A) that rotationally drives the radiation source holding portion, and a first restriction mechanism (42) that restricts rotation of the imaging table (24) about the axis of the support shaft (46), the first restriction mechanism is disposed on a side opposite to a radiation source with respect to the support shaft, and the drive mechanism is disposed on a radiation source side with respect to the first restriction mechanism and in a case where a center line of the arm extending in a direction connecting the radiation source and a center of the support shaft is assumed, the drive mechanism is disposed so as to intersect the center line.