Cam Follower Lock for Collapsible Roll Container Reliability

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Solution Overview

Problem

The existing collapsible roll containers are not reliable due to the vulnerability of the spring mechanism, which can wear out or fail, leading to unintended lock release, especially under intense handling and usage.

Innovation Solution

A collapsible roll container design that eliminates the need for a spring by using a cam and follower mechanism, where the protrusion aligns with a matching cavity using a cam surface with increasing and decreasing distances to lock the sidepieces in place, requiring only user force and gravity for operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring mechanism is used to lock the upper sidepiece in the use position, then the locking function is achieved, but the reliability deteriorates due to spring wear, damage, or disappearance under intensive handling

Engineering Contradiction:
Improvelocking mechanism reliabilityVSAvoidspring mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the spring component from the locking mechanism entirely. The cam and follower system achieves the locking function through geometric constraints and gravitational force alone, eliminating the vulnerable spring that could wear out or fail under intensive handling conditions.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The locking mechanism uses the container's own weight and gravity to maintain the locked position. The cam surface geometry automatically positions the follower, and gravity keeps the upper sidepiece in the use position without requiring additional energy-storing components like springs.

Inventive Principle:
Principle #25Self-service

2Reliability

If a cam surface with increasing and decreasing distance is used, then the protrusion can freely align with and enter the matching cavity for secure locking, but the device complexity increases

Engineering Contradiction:
Improvelocking engagement reliabilityVSAvoidcam surface geometry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cam surface uses a curved geometric profile with increasing and decreasing distance from the pivot axis. This curved geometry guides the follower through a controlled path, enabling the protrusion to freely align with and enter the matching cavity while maintaining a relatively simple overall mechanism structure.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If the spring is eliminated and only user force and gravity are used, then the reliability improves by removing wear and tear components, but the force required to operate the mechanism may increase

Engineering Contradiction:
Improvemechanism durabilityVSAvoidoperating force requirement
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The mechanism uses gravity as a counterbalancing force to maintain the locked position. The weight of the upper sidepiece itself provides the necessary force to keep the cam engaged with the follower, eliminating the need for springs while maintaining operational ease through gravitational assistance.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

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 enhances the reliability of the collapsible roll container by eliminating the need for a spring, ensuring secure locking without wear and tear issues, and allowing for efficient folding and stacking.

Implementation Method 1

The cam comprises a cam surface which is engageable by the follower. The cam surface has an increasing and then decreasing distance measured from the pivot axis, such that the follower engaging the cam surface increases a distance between the lower end of the upper sidepiece and the upper end of the lower sidepiece during a last but one part of an upwards pivoting movement to the use position to let the protrusion freely align with the matching cavity, and decreases the distance between the lower end of the upper sidepiece and the upper end of the lower sidepiece during a last part of the upwards pivoting movement to the use position to let the protrusion enter the matching cavity.

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 2

The upper sidepiece is pivotable about a pivot axis of the pivoting means downwards from the use position to a storage position

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP2692609B1Collapsible roll container
Publication Date: 2015.05.27 RTI SERVICES
  • EP2692609B1 patent drawingFigure 1~2
  • EP2692609B1 patent drawingFigure 3~5
  • EP2692609B1 patent drawingFigure 6~8

AI summary

The invention relates to a collapsible roll container (1) comprising a bottom (2), wheels (6a, 6b, 4b), at least one sidepiece (8, 10), comprising an upper sidepiece (18a, 18b), a lower sidepiece (20a, 20b), and pivoting means (22a, 22b, 22c), and a lock (12a, 12b, 12c). The lower sidepiece comprises an upper end(32a, 32b). The upper sidepiece comprises a lower end (30a, 30b) and is connected with the pivoting means to the lower sidepiece. It extends upwards in a use position, and is pivotable about a pivot axis (X1, X2) of the pivoting means downwards from the use position to a storage position. The lock comprises a protrusion (36a, 36b), and a matching cavity (38a, 38b). The pivoting means are designed to allow a translational movement of the lower end of the upper sidepiece. The lock further comprises a cam (42a, 42b) and a follower (46a, 46b). The cam comprises a cam surface (45a, 45b) which is engageable by the follower. The cam surface has an increasing and then decreasing distance measured from the pivot axis.