Press Brake Crowning With Eccentric Shafts and Force Multiplication

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Solution Overview

Problem

Press brakes face challenges in achieving downsizing and compactness of actuators while maintaining effective crowning of the lower table, often requiring large hydraulic cylinders that lead to cumbersome maintenance and energy inefficiencies.

Innovation Solution

The implementation of a force-increasing mechanism using a servo motor, eccentric shafts, and toggle mechanisms to transmit increased force for rotating the eccentric shafts, allowing for synchronous operation and reduced actuator size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a hydraulic cylinder is used as an actuator for crowning the lower table, then sufficient force can be applied to curve the central portion upward, but the actuator becomes large in size and cumbersome to maintain

Engineering Contradiction:
Improvecrowning forceVSAvoidactuator size
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

A force-increasing mechanism is introduced as an intermediary between the motor and the eccentric shaft. This mechanism includes a lever member integrally provided with the eccentric shaft and a link member pivotally connected to the lever member. The link member is pushed or pulled by the actuator to rotate the eccentric shaft, enabling force multiplication without requiring a large actuator.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If a hydraulic cylinder is used for crowning operations, then the required force can be achieved, but maintenance and management become cumbersome

Engineering Contradiction:
Improvecrowning forceVSAvoidmaintenance difficulty
Core Design Contradiction:
ForceVSEase of repair

Solution Approach 1:

The patent replaces the hydraulic cylinder-based mechanical system with a motor-driven force-increasing mechanism. This substitution eliminates hydraulic fluid, seals, and complex hydraulic components that require maintenance, while achieving the same force multiplication effect through mechanical leverage in the link member and lever member system.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Force

If a hydraulic cylinder is used for crowning, then sufficient force is available, but temperature rise of hydraulic operating oil occurs

Engineering Contradiction:
Improvecrowning forceVSAvoidhydraulic oil temperature
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

The patent eliminates the hydraulic system entirely by using a motor-driven mechanical force-increasing mechanism. This removes the source of hydraulic oil temperature rise while maintaining the ability to generate sufficient crowning force through the mechanical advantage provided by the link member and lever member configuration.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

This configuration enables a compact and energy-efficient actuator system that effectively performs crowning operations, enhancing the precision and efficiency of the press brake's bending process.

Implementation Method 1

a force-increasing mechanism for transmitting an output of an actuator to each eccentric shaft with a force increased

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

performing the crowning by rotating an eccentric shaft

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentEP3427854B1Press brake using force-increasing mechanism
Publication Date: 2021.06.16 AMADA HOLDINGS CO LTD
  • EP3427854B1 patent drawingFigure 1
  • EP3427854B1 patent drawingFigure 2
  • EP3427854B1 patent drawingFigure 3

AI summary

Provided are a crowning method and a press brake wherein, when crowning with a lower table is performed, the crowning is performed while rotating eccentric shafts using a force-increasing mechanism. In this press brake crowning method a front plate 11 and a back plate 13 are provided respectively at the front and back of a lower table 5, which is supported by left and right side frames 3L and 3R in a press brake 1, and crowning is performed while rotating eccentric shafts 23, which are provided in the lower table 5 with intervals therebetween in the left-right directions. A force-increasing mechanism 41 is provided between each eccentric shaft 23 and an actuator 31 for rotating each eccentric shaft 23, the output of the actuator 31 is increased by the force-increasing mechanism 41 and is transmitted to each eccentric shaft 23, and each eccentric shaft 23 is rotated, thereby performing crowning.