Pulley Block Self-Closing Device for Furniture to Reduce Opening Force
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Solution Overview
Problem
Existing self-closing devices for furniture moving parts, such as sliding doors or drawers, face issues with noise and increased force requirements due to direct linkage of the activating trigger to the shock absorber and spring, especially when a long stroke is needed, leading to inefficient operation and potential structural problems.
Innovation Solution
A shock-absorbing self-closing device with a pulley block mechanism connecting the activating trolley to the impulse spring unit, allowing for a longer arming stroke and reduced force requirement, incorporating a reinforcing shell for structural improvement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the activating trigger is directly linked to the shock absorber and spring unit by means of a slider to achieve a long stroke, then the automatic closing system can be activated much earlier, but the force to be applied during opening increases considerably
Solution Approach 1:
A transmitter wire is introduced as an intermediary element to connect the activating trigger to the spring unit and shock absorber. This wire transmits the activating force over a longer distance without requiring proportionally higher force, as it allows the force to be applied gradually along the length of the wire rather than directly through a rigid slider linkage.
Solution Approach 2:
The connection is transitioned from a direct linear mechanical linkage (slider) to a flexible linear transmission medium (transmitter wire). This dimensional change allows the force to be distributed along the length of the wire, enabling a longer stroke without the force multiplication problem inherent in rigid mechanical linkages.
2Force
If springs with greater length are used to reduce the force increase, then the self-closing devices would be too large, making it difficult to install them
Solution Approach 1:
The transmitter wire serves as a mediator that decouples the relationship between spring length and activating trigger stroke length. By using this flexible transmission medium, the system achieves a long stroke without requiring a proportionally long spring, as the wire can transmit force efficiently over extended distances without the same geometric constraints as a rigid spring.
3Loss of time
If a long stroke activating trigger is used to activate the self-closing system earlier, then the closing can be initiated sooner, but the force to be exerted on the spring increases proportionally with its elongation
Solution Approach 1:
The transmitter wire acts as a force-distributing intermediary that allows the activating trigger to move through a long stroke without requiring proportional force increase. The wire transmits the activating force gradually along its length, enabling early activation (long stroke) while keeping the force requirement manageable, unlike a direct rigid linkage where force would increase linearly with stroke length.
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
Enables earlier activation of the self-closing mechanism with reduced force needed during opening, increased service life of the shock absorber, and improved structural robustness by distributing the force and preventing compressive work on the shock absorber.
Implementation Method 1
the high speed generated by the spring in contraction is absorbed by the shock absorber in the final section of the drawer's travel, allowing smooth, gradual closing
Implementation Method 2
a transmitter wire (10) configured as a loop of a pulley block (11) between respective fixed pulley wheels (4a) and movable pulley wheels (4b) linked to the active end of the impulse spring unit (7)
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
Shock-absorbing self-closing device for moving parts of furniture, of the type having a trolley with guided displacement with an activating trigger locking its displacement in the armed position, in which the impulse spring is tensioned and, when activated, generates the self-closing energy with a speed controlled by the existence of a shock absorber, wherein the activating trolley (3) is connected to the end of the spring unit (7) by a transmitter wire (10) configured as a loop of a pulley block (11) between respective fixed pulleys (4a) and movable pulleys (4b) linked to the active end of the spring unit (7), producing proportionality between the active travel (15a) of the activating trigger (2) and the elongation travel (15b) of the spring unit (7).