Ship Container Coupling Piece Spacer Bearing Surface Design
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Solution Overview
Problem
Existing coupling pieces for securing containers on ships are prone to the 'opening effect' during high tensile forces, leading to disengagement and potential loss or injury, with limited pull-out force and safety reserve.
Innovation Solution
The coupling piece features a spacer with a bearing surface aligned with the first coupling projection, forming a uniform bearing surface that reduces pressure on the corner fitting edge, decreasing deformation and increasing the pull-out force by distributing force closer to the inner wall, thereby enhancing safety reserve and reducing vertical play.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the coupling piece is designed with a standard bearing surface on the first coupling projection, then the insertion operation is simple, but the pressure on the corner fitting edge is high causing deformation and reducing pull-out force
Solution Approach 1:
The bearing surface is segmented into two distinct surfaces: a first bearing surface on the first coupling projection and a second bearing surface on the spacer. This segmentation distributes the load from tensile forces across two separate contact areas, reducing the pressure concentration on any single edge of the corner fitting and thereby preventing deformation while maintaining simple insertion operation.
Solution Approach 2:
The solution extends the bearing functionality from a single surface to a multi-dimensional arrangement by adding the second bearing surface on the spacer at a different spatial location. This dimensional extension allows the load to be distributed across multiple points along the corner fitting, reducing stress concentration and increasing the overall pull-out force capacity.
2Device complexity
If the coupling piece uses a compact design, then the device complexity is low, but the deformation under tensile force is high leading to the opening effect
Solution Approach 1:
The spacer acts as an intermediary element between the first coupling projection and the corner fitting. It provides an additional bearing surface that mediates the force transmission, distributing the tensile load more evenly and reducing the direct pressure on the corner fitting edges. This intermediary structure prevents deformation and the opening effect while maintaining relatively simple device complexity.
3Strength
If the bearing surface is enlarged to distribute force, then the pull-out force increases, but the vertical play of the coupling piece increases
Solution Approach 1:
The bearing surfaces are strategically positioned at specific locations on the coupling piece and corner fitting to optimize force distribution. The first bearing surface is located on the first coupling projection while the second bearing surface is positioned on the spacer, creating localized contact zones that distribute pressure effectively without requiring an overall enlargement of the coupling piece dimensions, thus limiting vertical play.
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 reduces the opening effect, increases the pull-out force, and enhances safety reserve, allowing for higher payloads or increased safety with reduced deformation and vertical play, while maintaining easy insertion and locking.
Implementation Method 1
The bearing surface of the first coupling projection and the bearing surface of the spacer form a uniform bearing surface for the locking head and the overall length of the locking head is greater than the length of the lateral straight edge of a slot in the corner fitting. The bearing surface of the first coupling projection is accordingly enlarged by the bearing surface of the spacer. This reduces the pressure on the edge of the lower corner fitting of the upper container with the same tensile force.
Implementation Method 2
When coupled, the coupling piece wraps around the edges of the corner fittings in a C-shape. Tensile forces on the coupling piece due to lifting forces on the container, which are induced by rough seas, therefore cause the coupling piece to bend up elastically. Furthermore, the corner fittings of the containers are also elastically deformed.
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to a coupling piece (10) for connecting two stacked containers on board ships, comprising: a first coupling projection (11) which can be inserted into a lower corner fitting (12) of the upper container and pre-locked there; a second coupling projection (13) which, in a coupled state, engages in an upper corner fitting of the lower container; a bearing surface (20) of the first coupling projection (11) which, in the coupled state, rests on an inner edge of the lower corner fitting (10) of the upper container; and a spacer (27) of the first coupling projection (11) such that the coupling piece (10) can only be inserted into the lower corner fitting (12) of the upper container in a specific orientation.In order to reduce a so-called opening effect and consequently increase the pull-out force, the coupling piece (10) according to the invention is characterized in that the spacer piece (27) has a bearing surface (28) which is aligned with the bearing surface (20) of the first coupling projection (11) and, in the coupled state, also rests on the inner edge of the lower corner fitting (12) of the upper container.