Screw Tensioning Gear-Hydraulic Layout for High Force in Tight Space

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Solution Overview

Problem

Existing screw tensioning devices require a compact design while maintaining high pulling force multiplication, often resulting in an elongated overall design due to the need for a small piston portion with a large fluid storage capacity.

Innovation Solution

A device with a gear unit that transforms input torque into a higher output torque, combined with a hydraulically actuated system using a piston and volume portions with different effective cross-sections to apply or remove tension from a connecting element, allowing for a compact design without sacrificing pulling force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a small piston portion with large fluid storage capacity is used to achieve high pulling force multiplication, then the pulling force is sufficient, but the device becomes elongated in overall design

Engineering Contradiction:
Improvepulling forceVSAvoidoverall length
Core Design Contradiction:
ForceVSLength of moving object

Solution Approach 1:

The patent implements nesting by placing the piston portion inside the fixation element, which itself is contained within the support element. This nested arrangement allows the fluid storage capacity to be maximized within a compact footprint, achieving high pulling force multiplication without elongating the device's overall length.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a linear elongated design to a more three-dimensional compact configuration. By arranging the piston portion radially within the fixation element and using a support element with a bearing surface that extends perpendicular to the longitudinal axis, the device achieves force multiplication in a compact spatial arrangement rather than requiring linear extension.

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

2Length of moving object

If a compact design is pursued, then the device saves space, but the pulling force multiplication capability may be reduced

Engineering Contradiction:
Improveoverall lengthVSAvoidpulling force
Core Design Contradiction:
Length of moving objectVSForce

Solution Approach 1:

The nested arrangement of the piston portion within the fixation element allows the fluid storage volume to be efficiently utilized in a compact configuration. The piston can have a large effective base area relative to the device's overall dimensions, maintaining force multiplication capability while keeping the device compact.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent uses hydraulic principles with fluid communicated between the piston portion and fixation element to transmit and multiply force. The hydraulic system allows compact force transmission through fluid pressure, enabling high pulling force multiplication without requiring large mechanical components that would increase device length.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Force

If the piston portion has a small effective base area for force multiplication, then the pulling force is high, but the fluid storage capacity must be large which increases device length

Engineering Contradiction:
Improvepulling forceVSAvoidfluid storage volume
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The piston portion is nested within the fixation element, allowing the fluid storage volume to be contained within the same spatial envelope as the force multiplication mechanism. This enables the device to have both a small effective base area for high force multiplication and sufficient fluid storage capacity without increasing overall device volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent merges the fluid storage function with the structural components (fixation element and support element) rather than requiring a separate reservoir. The fixation element serves both as a structural component and as part of the fluid containment system, eliminating the need for additional volume that would increase device size.

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

The device achieves a compact design while maintaining sufficient pulling force, enabling efficient tensioning and loosening of connecting elements, such as screws, with improved space-saving characteristics compared to traditional devices.

Implementation Method 1

The device comprises a gear unit configured to transform an input torque applied to a transmission input element into an output torque applied to the actuating element which absolute value is higher compared to the input torque

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 2

the volume comprises two distinct portions, namely a piston portion delimited by the piston and the fixation element and an effective portion delimited by the fixation element and the support element which are fluid-communicatively connected. An effective base area of the piston portion is smaller than an effective base area of the effective portion... By this configuration, the actuating force applied onto the piston is hydraulically transformed into a force acting on the fixation element which is higher compared to that one acting on the piston

Methodology Applied
Scientific EffectHydraulic force multiplication: Hydraulic Press

Implementation Method 3

an actuating unit for translating a rotational movement applied to an actuating element into a translational movement of the engagement element relative to the component to be tightened and the support element

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP3898108B1Device for tensioning a connecting element
Publication Date: 2024.04.10 CATERPILLAR ENERGY SOLUTIONS
  • EP3898108B1 patent drawingFigure 1

AI summary

The present invention refers to a device (10) for tensioning a connecting element (12) fastened to a component (18, 20) to be tightened. The device (10) comprises an engagement element (24) connectable to the connecting element (12), and an actuating unit (44) for translating a rotational movement applied to an actuating element (46) into a translational movement of the engagement element (24) relative to the component (18, 20). Further, the device (10) comprises a gear unit (106) configured to transform an input torque (T1) applied to a transmission input element (108) into an output torque (T2) applied to the actuating element (46) which absolute value is higher compared to the input torque (T1).