Pull-Down Bed Locking Mechanism for Safe Vertical-Horizontal Positioning

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Solution Overview

Problem

Conventional pull-down beds fail to simultaneously provide a strong, reliable, compact, easy-to-operate, and aesthetically pleasing design with secure locking in both horizontal and vertical positions, while also being economically viable and easy to manufacture.

Innovation Solution

A pull-down bed with an automatic locking device featuring a hinged mattress frame, actuation device with radial slots and a transmission system, and gas springs for smooth operation, allowing for easy conversion between positions without visible fasteners, utilizing a folded sheet metal frame for aesthetic cleanliness and secure locking via pins and hooks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional pull down bed structure is used, then the basic function of providing a bed is achieved, but the locking reliability in both vertical and horizontal positions is insufficient

Engineering Contradiction:
Improvelocking reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking system is divided into two independent but coordinated locking devices: a first locking device for the vertical position and a second locking device for the horizontal position. Each locking device independently secures the mattress frame in its respective position, providing redundant safety without requiring a single complex locking mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary locking actions by automatically engaging the first locking device when the mattress frame approaches the vertical position and the second locking device when it approaches the horizontal position. This preliminary action prevents the frame from settling in intermediate positions and ensures secure locking before full position is reached.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a secure locking system is added to ensure reliability in both positions, then the locking safety is improved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveposition locking safetyVSAvoidmanufacturing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The locking devices are designed to automatically engage and disengage based on the position of the mattress frame itself. The system uses the frame's own movement to trigger the locking actions through gravitational force and mechanical linkages, eliminating the need for external actuators, motors, or complex control systems that would complicate manufacturing.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces intermediate mechanical elements such as linkages, levers, and gravitational force transmission mechanisms that connect the mattress frame position to the locking device activation. These intermediaries translate the simple positional state of the frame into automatic locking actions without requiring complex direct control systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If a compact design is implemented to minimize space occupation, then the space efficiency is improved, but the ease of operation and user effort required worsen

Engineering Contradiction:
Improvespace occupationVSAvoiduser effort required
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The patent incorporates a counterweight mechanism that balances the weight of the mattress frame, reducing the effort required by the user to move the frame between vertical and horizontal positions. The counterweight system compensates for gravitational force, making operation easier while maintaining a compact footprint.

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

Solution Approach 2:

The locking system is designed to be dynamically activated during the natural movement of the mattress frame. As the frame moves between positions, the locking devices automatically engage at the appropriate moments, eliminating the need for separate manual locking actions and simplifying user operation despite the compact design.

Inventive Principle:
Principle #15Dynamics

4Reliability

If automatic locking devices are added to prevent sudden movements, then the safety and reliability are improved, but the device complexity and operational mechanism complexity increase

Engineering Contradiction:
Improvesafety against sudden movementsVSAvoidoperational mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The automatic locking devices are designed to self-activate based on the position and movement of the mattress frame. The system uses the frame's own gravitational potential energy and mechanical position to trigger the locking actions, eliminating the need for external sensors, motors, or complex control systems that would increase operational mechanism complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The locking devices engage in preliminary action as the mattress frame approaches each stable position, preventing sudden movements or settling. The first locking device engages before the frame fully reaches the vertical position, and the second locking device engages before the frame fully reaches the horizontal position, ensuring smooth and controlled operation.

Inventive Principle:
Principle #10Preliminary action

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 ensures safe, reliable, and easy operation of the pull-down bed in both positions, occupying minimal space, with automatic locking preventing sudden movements and allowing for soft descent, enhancing user safety and reducing assembly complexity.

Implementation Method 1

gas springs for smooth operation

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a friction element, in particular a pin 22, which can be inserted in one of three radial slots 16, 17, 18

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2421409B1Pull down bed with automatic locking device
Publication Date: 2013.02.13 CLEI SRL
  • EP2421409B1 patent drawingFigure 1
  • EP2421409B1 patent drawingFigure 2
  • EP2421409B1 patent drawingFigure 3

AI summary

A pull down bed with automatic locking device has a movable framework, which constitutes a mattress frame, and is hinged to a container body, which constitutes a piece of furniture, so as to define a closed position, in which the mattress frame is substantially inside the piece of furniture, and an open position, for use as a bed, in which the mattress frame is in a horizontal position and rests on the ground by means of two feet. The mattress frame is hinged to the piece of furniture at one end and has its feet at the opposite end. The pull down bed includes a device for locking the mattress frame in the closed or horizontal position, which is actuated by an actuation device, which includes the feet.