Liftable Door Seal Force and Position Detection

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Solution Overview

Problem

Existing automatic door sealing systems fail to accurately determine when an upward force is applied to the sealing strip, which can occur due to improper installation, warping, or attempted manipulation, leading to ineffective sealing or security breaches.

Innovation Solution

Incorporating a second sensor to determine the position of the sealing strip and a controller to differentiate between normal and abnormal situations, including the use of servomotors to adjust door hinges and an alarm interface for exceptional conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a current sensor is used to detect when the sealing strip presses against an object, then the sealing process can be stopped to prevent damage, but false detection occurs when objects are lying on the floor causing the seal to stop before reaching the proper sealing position

Engineering Contradiction:

Improvesealing accuracyVSAvoidforce detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The force detection function is segmented from the current sensor and assigned to a dedicated force sensor (first sensor) that directly measures forces on the sealing strip. This separates the detection of normal sealing contact from abnormal obstructions, allowing the control unit to distinguish between legitimate sealing forces and false blockages.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A second sensor acts as an intermediary to detect the position of the sealing strip independently. By combining position information with force information, the control unit can determine whether an upward force is abnormal or part of the normal sealing process, resolving the false detection problem.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If the drive stops lowering when current exceeds a threshold, then damage from excessive force is prevented, but the sealing process may be interrupted before achieving proper seal contact

Engineering Contradiction:

Improvesealing force controlVSAvoidsealing completion

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The control unit continuously receives feedback from both the force sensor and position sensor during the lowering process. By monitoring the relationship between position and force in real-time, the system can distinguish between normal sealing forces (which increase gradually as the seal approaches the floor) and abnormal obstruction forces (which cause sudden spikes), allowing appropriate response decisions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The control strategy transitions from a static current threshold to a dynamic evaluation that considers the rate of force increase, the position of the sealing strip, and the relationship between these parameters. This dynamic approach allows the system to tolerate normal force increases during sealing while immediately responding to abnormal force spikes.

Inventive Principle:

Principle #15Dynamics

3Reliability

If the sealing strip is pressed against the floor to ensure tight sealing, then sealing effectiveness is improved, but the risk of damage from excessive force or manipulation increases

Engineering Contradiction:

Improvesealing effectivenessVSAvoiddamage risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The force sensor and position sensor are activated during the approach phase to establish a baseline of normal operation. The control unit learns the expected force-position relationship before the sealing strip contacts the floor, enabling it to distinguish between normal sealing forces and abnormal manipulation attempts that occur during or after sealing.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Continuous feedback from the force sensor allows the control unit to monitor the sealing process and detect any abnormal upward forces that indicate manipulation attempts. The system can respond by stopping the drive, activating an alarm, or adjusting the sealing force to maintain effectiveness while preventing damage.

Inventive Principle:

Principle #23Feedback

Data Source

PatentEP3851627A1Door with hinges, a door leaf and an electromotorically lowerable and liftable door seal

Publication Date: 2021.07.21 ATHMER

Figure 1

AI summary

15. The invention relates to a door with a liftable sealing strip, comprising a first sensor (4) for detecting when the sealing strip exerts an upward force on it. A control unit connected to the at least one first sensor (4) stops the lowering movement of the sealing strip as soon as the sealing strip is moved against an object. The door has at least one second sensor (5) connected to the control unit (6). Based on a signal supplied by the second sensor (5), the control unit (6) can determine whether the sealing strip reached a defined sealing position when the lowering movement was stopped, or whether it is in the defined sealing position. Thus, the position of the sealing strip when the first sensor detects an upward force can be determined using the sensor data from the second sensor.This can reveal whether a break-in attempt or an incorrect door position.