Hydraulic Deceleration Unit With Curved Contact to Prevent Eccentric Loading

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Solution Overview

Problem

Existing combined acceleration and deceleration devices are prone to overloading and eccentric loading issues, particularly when subjected to sudden forces, which can lead to swivel joint overload or off-center loading of the piston rod.

Innovation Solution

Incorporating a hydraulic cylinder-piston unit with a spring return and curved sliding and stop surfaces, where the sliding surface and stop surface have different radii of curvature, ensuring maximum contact in a single contact line, and allowing the sliding surface to detach from the stop surface when moving from the end position to the parking position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a swivel joint connects the piston rod and driver element, then the device can accommodate angular movements, but the swivel joint can be overloaded by sudden loads

Engineering Contradiction:
Improveangular movement accommodationVSAvoidswivel joint overload resistance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The guide block serves as an intermediary element between the piston rod and driver element. It guides the piston rod along a predetermined curved path, mediating the angular movement while distributing loads through the curved stop surface. This eliminates the need for a swivel joint that concentrates stress at a single pivot point, thereby preventing overload while maintaining angular movement capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the driver element is positioned at an angle during operation, then the device can achieve the required motion path, but the piston rod can be loaded off-center

Engineering Contradiction:
Improvemotion path achievementVSAvoidpiston rod eccentric loading resistance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The guide block features a curved stop surface with a specific radius of curvature that matches the desired motion path of the driver element. This curved geometry guides the piston rod along a predetermined arc, ensuring that the piston rod remains centrally aligned throughout its movement. The curvature transforms the angular positioning requirement into a guided linear motion along a curve, eliminating eccentric loading while achieving the required motion path.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Area of stationary object

If the sliding surface and stop surface have the same radius of curvature, then the contact area is maximized, but the contact is distributed rather than concentrated

Engineering Contradiction:
Improvecontact areaVSAvoidcontact line precision
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The guide block's stop surface has a different radius of curvature than the driver element's sliding surface. This asymmetric curvature relationship ensures that the two surfaces contact along a precise line rather than over a distributed area. The line contact concentrates the force transmission while maintaining manufacturing precision, as the asymmetric geometry naturally defines a unique contact line that is easier to control and manufacture with high precision.

Inventive Principle:
Principle #4Asymmetry

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 enhances the device's reliability by preventing eccentric force application on the piston rod, ensuring stable operation even under multiple sudden loads and maintaining contact between the sliding and stop surfaces to prevent deformation and leaks.

Implementation Method 1

The delay device has at least one hydraulic cylinder-piston unit with a spring return

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

hydraulic cylinder-piston unit with a spring return

Methodology Applied
Scientific EffectElastic potential energy: Spring

Data Source

PatentEP3070248B1Combined accelerating and decelerating device with overload protection
Publication Date: 2018.03.14 ZIMMER GUNTHER
  • EP3070248B1 patent drawingFigure 1
  • EP3070248B1 patent drawingFigure 2~4
  • EP3070248B1 patent drawingFigure 5~7

AI summary

In a combined acceleration and deceleration device with a carrier housing and a carrier element which is movable along at least one guide track of the carrier housing between a force and/or form-locking park position and an end position under the control of an acceleration arrangement and a deceleration arrangement including a hydraulic cylinder-piston unit with a spring return structure. The cylinder-piston unit carries a guide member which is guided by the guide track and has a curved stop surface and the carrier element has a curved push surface with the push surface area and the stop surface area having different radii of curvature so that they contact each other maximally along a contact line.