Center Clamp Slide-Cylinder Layout for Large Axial Stroke

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Solution Overview

Problem

Conventional center clamps have an unsatisfactory relationship between axial length and achievable axial stroke of the slides, requiring a longer axial length for the desired stroke, which is undesirable for compact designs.

Innovation Solution

The center clamp design features working cylinders integrated within the carriages, with drive pistons that are rigidly connected by a piston rod, allowing for a pressure medium drive to move the carriages relative to the pistons, enabling a larger axial stroke with a shorter axial length by connecting and pressurizing the pistons and cylinders in a way that maximizes stroke while minimizing length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the axial length of the center clamp is increased to achieve a desired axial stroke of the slides, then the stroke is improved, but the compactness of the design deteriorates

Engineering Contradiction:
Improveaxial stroke of slidesVSAvoidaxial length of center clamp
Core Design Contradiction:
Length of moving objectVSLength of stationary object

Solution Approach 1:

The working cylinders are arranged inside the housing in a nested configuration, with the drive pistons positioned within the cylinders. This nesting allows the stroke-generating components to be contained within the overall structure, achieving large axial stroke without proportionally increasing the external axial length of the center clamp.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The coupling mechanism uses a pivoting lever that rotates about a vertical pivot axis, transforming linear motion into rotational motion and back. This dimensional transformation allows the slides to achieve axial stroke while the overall axial length remains constrained by the housing dimensions rather than the stroke length.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Length of stationary object

If the axial length of the center clamp is reduced for compact design, then the compactness is improved, but the achievable axial stroke of the slides deteriorates

Engineering Contradiction:
Improveaxial length of center clampVSAvoidaxial stroke of slides
Core Design Contradiction:
Length of stationary objectVSLength of moving object

Solution Approach 1:

The slider-crank mechanism with the pivoting lever pre-establishes a mechanical advantage that amplifies the stroke output relative to the input displacement. By designing the lever arm lengths and crank dimensions appropriately, the system compensates for the limited axial space available, generating larger slide stroke from smaller piston displacement.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The pivoting lever acts as an intermediary mechanism between the drive pistons and the slides. It receives the limited linear displacement from the pistons and transforms it into a larger axial stroke for the slides through its rotational motion and geometric configuration, effectively mediating the stroke amplification.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If conventional arrangement of working cylinders outside the slides is used, then the structural simplicity is maintained, but the stroke-to-length ratio deteriorates

Engineering Contradiction:
Improvestructural arrangementVSAvoidaxial stroke to axial length ratio
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

The working cylinders are merged with the slides by arranging them within the same structural envelope. The cylinders are positioned inside the housing with their axes parallel to the slide movement direction, combining the functions of support and actuation within a unified compact structure, thereby improving the stroke-to-length ratio.

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 design achieves a significantly larger maximum stroke of the slides with a relatively short axial length, improving the stroke-to-length ratio and providing a high clamping force, suitable for various applications.

Implementation Method 1

The pressure medium drive is designed to displace at least one drive piston (5, 6) in the associated working cylinder (7, 8) by application of pressure to the drive piston (5, 6) in the working cylinder (7, 8)

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

although the type of hydraulic oil supply is not relevant in this case

Methodology Applied
Scientific EffectPneumatic pressure: Pressure Gradient

Data Source

PatentEP4302925A1Center clamp
Publication Date: 2024.01.10 LUGWIG EHRHARDT GMBH
  • EP4302925A1 patent drawingFigure 1A~1C
  • EP4302925A1 patent drawingFigure 2A~2B
  • EP4302925A1 patent drawingFigure 2C~2D

AI summary

The invention relates to a center clamp (1) for centrally clamping a workpiece, comprising two counter-rotating slides (3, 4) each with a clamping jaw, a coupling mechanism (9) for counter-rotating the two slides (3, 4), and a piston drive (5, 6, 7, 8). The invention provides that the working cylinder (7, 8) is arranged in one of the slides (3, 4) and moves with the slide (3, 4), and that the drive piston (5, 6) is displaceable relative to the slide (3, 4) driven by the drive piston (5, 6).