Hinge Pin Mounted Door Switch for Tamper-Proof Position Sensing

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Solution Overview

Problem

Current door position sensing technologies require invasive mounting methods, such as drilling and screwing, which are time-consuming and destructive, and do not offer universal solutions for various door installations, leading to high manufacturing costs and installation challenges.

Innovation Solution

A mechanical switch is mounted by replacing a hinge pin, using spring-biased lever arms that move with the door, allowing for door position detection without drilling or screwing, and featuring a secure design to prevent tampering and magnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a two part magnetic switch or button type switch is used, then door position monitoring is achieved, but mounting requires drilling into door jamb and door which is time consuming and destructive

Engineering Contradiction:

Improvedoor position monitoringVSAvoidinstallation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The invention extracts the mounting function from the door structure itself by utilizing the existing hinge pin as the mounting carrier. The switch is attached to the hinge pin rather than requiring separate mounting operations on the door and door jamb, thereby eliminating the time-consuming drilling and screwing processes while maintaining reliable door position monitoring.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The hinge pin serves multiple functions: it continues to perform its original function of connecting the door to the door jamb, and simultaneously serves as the mounting carrier for the door position switch. This multi-functionality eliminates the need for separate mounting hardware and operations, reducing installation time and complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If a two part magnetic switch or button type switch is used, then door position monitoring is achieved, but mounting requires drilling and screwing which is destructive to door and door jamb

Engineering Contradiction:

Improvedoor position monitoringVSAvoiddamage to door and door jamb

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of manufacture

If a flush mounted two part magnetic switch is used, then mounting surface requirements are reduced, but it does not work well with door/jamb configurations with inadequate flush mounting surface

Engineering Contradiction:

Improvemounting surface requirementsVSAvoidcompatibility with various door configurations

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Reliability

If mechanical switches integral to hinge are used, then door position monitoring is achieved, but requires detailed and elaborate machining and design involving specific hinge designs

Engineering Contradiction:

Improvedoor position monitoringVSAvoidmachining and design complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention segments the door position monitoring function from the hinge structure itself. Instead of integrating the switch into the hinge (which would require elaborate machining), the switch is mounted on the hinge pin as a separate, independent component. This segmentation simplifies both the hinge design and the switch mounting, reducing overall device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of integrating the switch into the hinge structure (conventional approach), the invention inverts the mounting approach by attaching the switch to the hinge pin that connects the door and door jamb. This inversion simplifies the mounting process and reduces machining complexity while maintaining functional reliability.

Inventive Principle:

Principle #13The other way round (Inversion)

5Reliability

If switches mounted by drilling and screwing are used, then door position monitoring is achieved, but manufacturing costs are high and installation is time consuming

Engineering Contradiction:

Improvedoor position monitoringVSAvoidmanufacturing and installation cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution provides a low-cost, easy-to-install, and tamper-proof door position sensing system that is universally applicable, minimizing installation time and damage to doors, while maintaining hinge strength and operation.

Implementation Method 1

A coil spring is coiled around the hinge pin. The spring has two opposite ends. Each end engages a respective one of the two pieces. The piece of the fixed portion is biased by the spring against the fixed part of the door hinge and/or against the door frame. The piece of the rotatable portion is biased by the spring against the rotatable part of the door hinge and/or against the door.

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8510989B2Hinge pin mounted door switch

Publication Date: 2013.08.20 ROBERT BOSCH GMBH

AI summary

A door position detecting apparatus comprises a switch including a body having two electrical contacts and a through-channel. The through-channel of the switch receives a hinge pin inserted therethrough and further inserted into a door hinge. Two lever arms extend from the body. Each of the arms is attached to a respective one of the electrical contacts. The arms have a first position relative to each other wherein the contacts are electrically connected to each other, and a second position relative to each other wherein the contacts are electrically disconnected from each other. Biasing means biases the arms against a fixed door jamb and a rotatable door, respectively, such that one of the arms follows movement of the rotatable door from an open position of the door to a closed position of the door. Monitoring means monitors whether the contacts are electrically connected to each other.