Toggle Lever Crimping Pliers with Adjustable Knee Angle

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Solution Overview

Problem

Existing crimping pliers face challenges in generating consistent pressing forces across various workpiece geometries and materials, leading to inadequate force distribution when handling workpieces with different cross-sectional areas, which can result in either insufficient or excessive force application.

Innovation Solution

The design incorporates a toggle lever drive with a roller-curve principle and a ratchet mechanism, along with a force-displacement compensation element, such as a spring element, to manage the movement of the actuating elements and dies, allowing for adjustable knee angles and flexible deformation to accommodate workpieces of varying sizes, ensuring controlled force application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a toggle lever drive is used to generate pressing forces, then the required maximum pressing forces can be generated by manual actuation, but the pressing force distribution becomes inconsistent when handling workpieces with different cross-sectional areas

Engineering Contradiction:
Improvepressing forceVSAvoidadaptability to different workpiece geometries
Core Design Contradiction:
ForceVSAdaptability or versatility

Solution Approach 1:

The patent applies the dynamics principle by making the knee angle of the toggle lever drive adjustable during operation. The drive mechanism transitions from a fixed geometric configuration to a dynamically adjustable one, allowing the knee angle to be changed based on the workpiece cross-sectional area. This enables the pressing force characteristics to be adapted to different workpiece geometries while maintaining the ability to generate required maximum pressing forces through manual actuation.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the knee angle of the toggle lever drive is fixed, then the pressing force characteristics are determined, but the device cannot accommodate workpieces with cross-sectional areas differing by large factors

Engineering Contradiction:
Improvepressing force controlVSAvoidrange of applicable workpiece sizes
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamics by enabling the knee angle to be dynamically adjusted during operation. The drive mechanism includes components that allow changing the geometric relationship between toggle levers based on the specific workpiece being pressed. This dynamic adjustment capability expands the range of applicable workpiece sizes from a fixed set to a continuous range, while maintaining precise pressing force control through the toggle lever mechanical advantage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by modifying the knee angle parameter of the toggle lever drive to match the workpiece cross-sectional area. The system includes adjustment mechanisms that change the geometric parameters of the drive mechanism, specifically the knee angle, to optimize pressing force distribution for each workpiece size. This parameter adjustment enables the device to handle workpieces with cross-sectional areas differing by factors of up to 200.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a ratchet mechanism is added to secure the hand lever position, then operational safety is improved, but the device complexity increases

Engineering Contradiction:
Improveoperational safetyVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the merging principle by integrating the ratchet mechanism with the existing toggle lever drive and hand lever assembly. The ratchet components are combined with the mechanical structure already present, sharing common elements such as the hand lever, pivot points, and mounting structures. This integration approach adds the security function without proportionally increasing overall device complexity, as the ratchet mechanism utilizes the existing structural framework.

Inventive Principle:
Principle #5Merging (Combining)

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 crimping pliers to effectively handle workpieces with cross-sectional areas differing by a factor of up to 200, providing precise control over pressing forces and preventing excessive deformation, while maintaining operational ease and safety.

Implementation Method 1

force-displacement compensation element, such as a spring element

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3012924B1Jointing clamp
Publication Date: 2017.12.13 WEZAG GMBH WERKZEUGFABRIK
  • EP3012924B1 patent drawingFigure 1
  • EP3012924B1 patent drawingFigure 2
  • EP3012924B1 patent drawingFigure 3

AI summary

The invention relates to a crimping tool with two hand levers (3, 5) and two actuating elements (9, 10) arranged in the area of ​​a crimping head (4), which actuate dies (12) between which a workpiece can be crimped. A toggle lever drive (33) with two toggle levers (34, 35) forming a toggle angle (36) acts between the hand levers (3, 5) and the actuating elements (9, 10). One toggle lever (34) is formed by a roller (23) which is rotatably mounted relative to the hand lever (5). The roller (23) rolls on a cam track (24) fixed to the other hand lever (3). A positive locking mechanism (48) is formed by a locking toothed lever (28) which is rotatably mounted relative to the roller (23). One lever part (30) of the locking tooth lever (28) is coupled to the hand lever (3) via a sliding guide, while the other lever part (29) of the locking tooth lever (28) forms a locking tooth (31) of the positive locking mechanism (48).