Fluid-Controlled Crimping Tool for Precise Axial Force

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Solution Overview

Problem

Current crimping tools, such as pneumatic and hydraulic riveters, lack precision due to significant effort required to move the primary piston, leading to friction and reduced accuracy in axial force application on the rivet, making them inefficient for precise and rapid crimping operations.

Innovation Solution

A crimping tool design that uses a main valve to control the pressure of a first fluid, eliminating the need to compress a return spring, thereby reducing piston friction and allowing better control over the traction force, with a system comprising a movable main valve member, a trip valve, a detection valve, and a motor control valve to manage the crimping process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a pneumatic or hydraulic system is used to drive the primary piston, then the crimping operation can be automated, but the system requires significant force to move the piston, resulting in friction and lack of precision in axial force application

Engineering Contradiction:
Improveautomation of crimping operationVSAvoidprecision of axial force application
Core Design Contradiction:
Extent of automationVSManufacturing precision

Solution Approach 1:

The patent removes the return spring from the system, extracting the source of friction that was preventing precise force application. By eliminating the spring that needed to be compressed during piston movement, the system achieves both automation and precision without the harmful friction effects

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a main valve as an intermediary control element that precisely regulates fluid pressure to the piston. This valve acts as a mediator between the power source and the piston, enabling precise control of axial force application while maintaining automation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a return spring is used in the hydraulic system, then the piston can return to its initial position, but the spring compression creates friction on the piston and reduces control precision

Engineering Contradiction:
Improvepiston return functionVSAvoidfriction on piston
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent completely removes the return spring from the system, eliminating the friction source. The piston return function is achieved through alternative means (fluid pressure control via the main valve) that do not involve mechanical spring compression, thereby eliminating energy loss to friction

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical spring-based return mechanism with a fluid-pressure-based system controlled by the main valve. This substitution eliminates the mechanical friction inherent in spring-compression systems while maintaining the essential piston return function

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

3Manufacturing precision

If the same fluid is used to move the piston and control pressure, then friction is significantly reduced and control is improved, but a more complex valve system is required to manage fluid direction

Engineering Contradiction:
Improvecontrol of crimping forceVSAvoidvalve system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The main valve performs multiple functions: it controls pressure increase, directs fluid to move the piston, manages pressure decrease, and controls fluid flow to the outlet terminal. By consolidating these functions into a single multi-functional valve, the system achieves precise control without proportionally increasing overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 tool achieves precise and rapid crimping by minimizing friction and enhancing control over the crimping force, resulting in improved speed and accuracy of the crimping operation.

Implementation Method 1

a first chamber (8) containing a first fluid (9), the first fluid (9) being suitable to increase in pressure so as to move the rod (7) in a crimping direction

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

a second chamber (10) containing a second fluid (11), the main piston (12) being movably mounted in the second chamber (10) so as to be moved by the second fluid (11) to decrease the pressure of the first fluid (9)

Methodology Applied
Scientific EffectHydraulic pressure control: Hydraulic Press

Data Source

PatentEP4103359B1Tool and method for crimping an element onto a support member
Publication Date: 2023.11.29 BOLLHOFF OTALU SA
  • EP4103359B1 patent drawingFigure 1
  • EP4103359B1 patent drawingFigure 2
  • EP4103359B1 patent drawingFigure 3

AI summary

Tool (2) for crimping an element (2) onto a support member (3), comprising a movably mounted rod (7), a first chamber (8) containing a first fluid (9), a second chamber (10) containing a second fluid (11), a piston (12) movably mounted inside the second chamber (10) and separating the second chamber (10) into first and second compartments (30, 31), an input terminal (13) suitable for being connected to a second fluid (11) source, and a main valve (14) configured to direct the second fluid (11) into the second compartment (31) in order to move the piston (12) to reduce the pressure of the first fluid (9) and drive the rod (7) in a direction opposite to a crimping direction.