Ceiling Lift Tilt Control via Dual Motor Height Limiting

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Solution Overview

Problem

Existing ceiling lift systems face challenges in safely and comfortably managing the tilt of large or heavy patients, as they can lead to uncomfortable or hazardous positions due to uncontrolled height differences between spreader bars, particularly for patients with a high Body Mass Index or weight above 160 kg.

Innovation Solution

A dual motor ceiling lift system with a controller that sets a maximum height difference between spreader bars at plus or minus 350 mm, preventing further tilt when this limit is reached, ensuring patient safety and comfort by allowing only motion away from the limit, thus preventing reclining or seating beyond a defined position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the height difference between spreader bars is increased to provide tilting function for patient comfort, then patient comfort and caregiver effort are improved, but patient safety deteriorates due to hazardous positions

Engineering Contradiction:
Improvepatient comfortVSAvoidpatient safety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control system continuously monitors the height difference between spreader bars and provides feedback to prevent exceeding safe limits. The controller receives signals from sensors measuring spreader bar positions and automatically prevents operation when the height difference approaches dangerous thresholds, thus maintaining patient safety while allowing comfortable positioning within safe ranges.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system pre-establishes maximum height difference limits and prevents operation before hazardous conditions can occur. By setting predetermined safe operating boundaries and blocking control signals that would exceed these boundaries, the system proactively prevents unsafe tilting positions rather than reacting after danger arises.

Inventive Principle:
Principle #9Preliminary anti-action

2Strength

If the lifting capacity is increased to handle larger patients, then the system can support heavier patients, but device complexity increases

Engineering Contradiction:
Improvelifting capacityVSAvoidsystem complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The system divides the lifting function into two independent motor units, each capable of supporting heavy loads individually. This segmentation allows each motor to be optimized for high strength without requiring a single overly complex high-capacity motor, and enables independent control of each spreader bar for tilting operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dual motor unit system serves multiple functions: it can lift heavy patients independently, provide tilting capability through coordinated operation, and maintain patient position through differential control. This multi-functionality reduces the need for separate specialized devices, effectively managing system complexity while handling diverse patient care requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If dual motor units are used to enable tilting function, then patient comfort is improved, but device complexity increases

Engineering Contradiction:
Improvepatient comfortVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The control system merges the functions of two motor units into a coordinated system managed by a single controller. The controller synchronizes both motors to work together for tilting operations, combining their capabilities to provide comfortable patient positioning while centralizing control logic to manage complexity rather than having separate independent control systems.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3220872B1Ceiling lift tilt management system
Publication Date: 2022.10.05 ARJO IP HLDG AB
  • EP3220872B1 patent drawingFigure 1~3
  • EP3220872B1 patent drawingFigure 4~5
  • EP3220872B1 patent drawingFigure 6~7

AI summary

A ceiling lift tilt management system includes first and second motor units, which are attachable to a rail system of a medical care facility. Each motor unit includes a flexible strap, which can be coiled or uncoiled within the motor unit to raise or lower a spreader bar attached thereto. Coiling or uncoiling of the straps can cause raising or lowering of a sling attached to the spreader bars. The system also allows for tilting of the spreader bars by coiling or uncoiling a leading motor unit strap. The system includes a control system that measures the relative lengths of the two straps in order to ensure that relative tilt between the spreader bars does not exceed a threshold. Once a threshold tilt for height difference is reached, further user requests for additional tilting are prohibited. Patient comfort and safety are therefore ensured.