Cylindrical Letterbox Structure for Vandal-Resistant Secure Access

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current letterboxes lack enhanced security and protection features against external actions and vandalism while maintaining manufacturing simplicity and cost-effectiveness.

Innovation Solution

A cylindrical letterbox design featuring a thick steel base, rust-resistant central body with improved anchoring and security elements, including a secure door mechanism with a magnetized plate and double-bolt lock, and anti-corrosion treatment to ensure durability and security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional letterbox structures are used, then manufacturing simplicity is maintained, but security and protection levels are insufficient

Engineering Contradiction:
Improvesecurity and protectionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The letterbox is divided into three distinct segments: base portion, central body, and cap portion. Each segment can be manufactured separately and then assembled through welding, allowing for simplified production of individual components while achieving high security through the integrated structure. The segmentation enables specialized design features in each portion without complicating the overall manufacturing process.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The letterbox employs composite construction combining thick steel sheets (5mm) for the base, iron plates for the central body, and metal plates (2mm) for the cap, all protected by anti-corrosion coatings. This composite material approach enhances security and durability while maintaining manufacturing feasibility through standard metalworking processes and welding techniques.

Inventive Principle:
Principle #40Composite materials

2Strength

If thicker materials and improved anchoring are used, then resistance to vandalism and external actions is increased, but production costs increase

Engineering Contradiction:
Improveresistance to vandalismVSAvoidproduction cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

Different thicknesses and material properties are applied to different portions of the letterbox based on their specific functional requirements. The base uses 5mm thick steel for maximum anchoring strength, the central body uses iron plates with anti-corrosion protection for durability, and the cap uses 2mm metal plates. This localized quality approach optimizes material usage and reduces overall production costs while maintaining high resistance to vandalism where most critical.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention combines multiple security features into integrated components: the anchoring system merges thick base material with welded anchorings; the door system combines robust hinges, double-bolt locks, and magnetized plates; the protective features integrate anti-corrosion treatment, folding lids, and fixed visors. This merging reduces the need for separate security devices and lowers overall production costs.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If conventional door security mechanisms are used, then ease of operation is maintained, but security against unauthorized access is insufficient

Engineering Contradiction:
Improvedoor securityVSAvoiddoor operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The door system incorporates dynamic elements including folding lids with hinges that allow smooth opening and closing operations, and a double-bolt lock mechanism that provides secure locking. The magnetized plate integrated into the door offers automatic alignment and secure engagement. These dynamic features maintain ease of operation for authorized users while providing high security against unauthorized access through multiple locking points and robust construction.

Inventive Principle:
Principle #15Dynamics

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 cylindrical letterbox provides increased protection and security for stored documents without increasing manufacturing complexity or costs, ensuring resistance to vandalism and harsh weather conditions.

Implementation Method 1

a magnetized plate (8c) integrated to the door (8)

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP2090203B1Cylindrical letterbox
Publication Date: 2010.07.21 SOC ESTATAL CORREOS Y TELEGRAFOS
  • EP2090203B1 patent drawingFigure 1.1~1.4
  • EP2090203B1 patent drawingFigure 2.1~2.2
  • EP2090203B1 patent drawingFigure 3.1~3.2

AI summary

A cylindrical letterbox, of the type installed in public thoroughfares or similar for the reception of postal objects, is disclosed, the letterbox configuration of which is of conventional type, comprised of a lower body or base and an upper base equipped with an access door and destined to contain the sack that collects postal objects introduced through an entrance slot within reach of users. The letterbox assembly includes characteristics that provide substantial improvements with respect to other letterboxes of the current state of the art materialised in the provision of strips inside the lower body, orthogonally intercrossed and welded to the edge of the body, to support the sack; anchoring elements of the lower body in angularly equidistant positions; an entrance slot protected against the introduction of foreign objects, for which purpose it includes a ramp associated to a door that opens by gravity and is equipped with a closing magnet; and reinforcement strips welded to the sack extraction door, that prevent the warping or deformation thereof and which, together with the safety lock that actuates internal catch elements, guarantee the secure use of the letterbox.