Formwork Turnbuckle Wedge Release in Tight Installation Spaces

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Solution Overview

Problem

Existing turnbuckles for clamping frame formwork elements face challenges in difficult-to-access installation situations, such as when mounted on lower horizontal struts or in close proximity, where wedges cannot be easily released due to space constraints, and require additional tools like hammers for operation.

Innovation Solution

A turnbuckle design featuring a crossbar that can be moved between locking and unlocking positions to control the stroke of the wedge orthogonally, allowing easy release without the need for hammer blows, even in constrained spaces, by increasing or limiting the wedge's stroke relative to the toothed section.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the turnbuckle is mounted on lower horizontal struts or in close proximity to other turnbuckles, then the clamping function is achieved, but the wedge cannot be easily released due to space constraints and requires additional tools like hammers

Engineering Contradiction:
Improveease of wedge releaseVSAvoidavailable space for hammer operation
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The invention extracts the wedge from the constrained space below the crossbeam by providing a guide device with a guide opening that allows the wedge to be removed laterally from the side of the crossbeam. This eliminates the need for hammer blows from below and enables wedge removal in situations where space below the crossbeam is insufficient.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The guide device acts as an intermediary mechanism between the wedge and the external environment. It provides a controlled path through the guide opening that allows the wedge to be extracted laterally without requiring direct access from below the crossbeam, thus mediating the conflict between clamping function and release accessibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If multiple turnbuckles are arranged vertically adjacent to each other to clamp interfaces under high forces, then the clamping capacity is increased, but the wedges interfere with each other and sufficient distance cannot be maintained for hammer operation

Engineering Contradiction:
Improveclamping capacityVSAvoidwedge operation accessibility
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The invention changes the dimension of wedge extraction from vertical (below the crossbeam) to lateral (through the side guide opening). This allows multiple turnbuckles to be arranged vertically adjacent to each other without their wedges interfering with each other, as each wedge can be independently removed through its own guide opening without requiring vertical clearance below the crossbeam.

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

3Reliability

If the wedge is driven deep into the toothed section to ensure secure clamping, then the clamping reliability is improved, but the wedge cannot be released by hammer blows in constrained positions

Engineering Contradiction:
Improveclamping reliabilityVSAvoidwedge release in constrained spaces
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The guide device segments the wedge extraction path from the general space below the crossbeam into a specific lateral path through the guide opening. This allows the wedge to be driven deep into the toothed section for secure clamping while providing a dedicated extraction route that bypasses space constraints, enabling reliable release even in constrained positions where hammer blows from below are not feasible.

Inventive Principle:
Principle #1Segmentation

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

Enables quick and tool-free operation of the turnbuckle, facilitating easy clamping and release of frame formwork elements, particularly in challenging installation scenarios, enhancing operational efficiency and adaptability.

Implementation Method 1

a wedge (20) which, guided by the guide device (19), can be displaced along a wedge-driving direction (B) and can be brought into engagement with at least one of the teeth (13)

Methodology Applied
Scientific EffectWedge mechanism: Wedge

Implementation Method 2

there is provided a transverse bar (21) which is displaceable transversely to the wedge insertion direction between a locking position and an unlocking position

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Data Source

PatentEP4499951B1Turnbuckle for tensioning frame formwork elements
Publication Date: 2026.02.25 PERI GMBH
  • EP4499951B1 patent drawingFigure 1
  • EP4499951B1 patent drawingFigure 2~3
  • EP4499951B1 patent drawingFigure 4~5

AI summary

The invention relates to a turnbuckle (1) for bracing frame formwork elements (2), comprising a first clamping device (7) which has a crossmember (9) and a first clamping jaw (10). The crossmember (9) has a toothed section (12) comprising a row of track teeth (13) which are arranged one behind the other and extend in parallel with one another. The turnbuckle (1) furthermore has a second clamping device (8) with a second clamping jaw (14) and a guide device (19). The second clamping device (8) can be moved in a bracing direction along the crossmember (9) towards the first clamping jaw (10). The turnbuckle (1) further has a wedge (20) which can be displaced in a guided manner by the guide device (19) along a wedge insertion direction and can be brought into engagement with at least one of the track teeth (13) in order to fix the two clamping devices (7, 8) in a bracing position with respect to one another. The guide device (19) has a transverse bolt (21) which can be displaced transversely to the wedge insertion direction between an unlocking position and a locking position. The crossmember (21) is designed and arranged in such a way that the transverse bolt (21) in the locking position delimits a stroke of the wedge (20) in a direction orthogonal to the toothed section (12) in such a way that the wedge (20) in the clamping position can be brought into engagement with the at least one track tooth (13). The crossmember (21) enables a greater stroke of the wedge (20) in the unlocking position.