Guide device and fixture in which same is used

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Solution Overview

Problem

Existing guide apparatuses for tables, drawers, and cabinets fail to maintain the inner rail at a predetermined position when faced with unexpected forces or heavy loads due to insufficient holding force.

Innovation Solution

A guide apparatus with a position holding mechanism where plate spring portions are supported at both ends, allowing for increased spring force and holding force, even when compact, by using a pair of plate spring portions that sandwich a shaft on the outer rail, with specific inclinations and support structures to enhance the holding capability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a cantilevered plate spring portion is used in the position holding mechanism, then the device complexity is reduced and manufacturing is simplified, but the spring force and holding force become insufficient, especially when the table or drawer is heavy or subjected to large unexpected forces

Engineering Contradiction:
Improveholding forceVSAvoidposition holding mechanism complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The position holding mechanism is segmented into multiple functional components: a pair of plate spring portions (first and second), a shaft with engagement features, and a housing structure. This segmentation allows each component to be optimized independently - the plate spring portions can be designed with specific thicknesses and lengths to maximize spring force, while the shaft provides a dedicated engagement body. The segmentation resolves the contradiction by enabling a more complex but effective multi-component system that delivers sufficient holding force.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies parameter changes by specifying precise geometric parameters of the plate spring portions, including thickness (t1, t2), lengths (L1, L2), and positioning dimensions (a1, a2, b1, b2). These parameter optimizations maximize the spring force generated by the plate springs while maintaining compact dimensions. By carefully controlling these parameters, the system achieves high holding force without requiring excessive complexity in the overall mechanism design.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If the plate spring portion is made compact to reduce space, then the volume is reduced, but the spring force may be compromised

Engineering Contradiction:
Improveposition holding mechanism volumeVSAvoidspring force
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The patent resolves this contradiction through optimized parameter selection for the plate spring portions. Specific thickness values (t1, t2) and length values (L1, L2) are specified to maximize spring force within compact dimensions. The parameters are carefully balanced so that the plate springs generate sufficient elastic force while occupying minimal space within the housing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The position holding mechanism utilizes composite structural design combining plate spring portions made of elastic material with a rigid housing and shaft. This composite approach allows the flexible plate springs to generate high spring force while the rigid components provide structural support and compact geometry. The combination of different material properties enables both compact size and high spring force.

Inventive Principle:
Principle #40Composite materials

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 effectively increases the holding force of the inner rail at both pull-in and pull-out positions, ensuring the inner rail remains at a predetermined position even under unexpected forces or heavy loads, while maintaining a compact design.

Implementation Method 1

a pair of plate spring portions (22a, 22b) placed on the outer rail (1) in such a manner as to sandwich the shaft (21)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a slide rail including an outer rail and an inner rail slidably assembled to the outer rail via rolling elements

Methodology Applied
Scientific EffectRolling friction: Roller

Implementation Method 3

biases the rotary latch toward the inner rail by a torsion spring, and holds the inner rail by the friction force produced between the rotary latch and the inner rail

Methodology Applied
Scientific EffectTorsion spring force: Torsion Spring

Data Source

PatentEP3318772B1Guide device and fixture in which same is used
Publication Date: 2021.03.03 THK CO LTD
  • EP3318772B1 patent drawingFigure 1
  • EP3318772B1 patent drawingFigure 2
  • EP3318772B1 patent drawingFigure 3

AI summary

A guide apparatus is provided which can increase a holding force that holds a table, a drawer, a cabinet, a device, or the like at a predetermined position. An engagement body (43) is placed on a second member (42b) . A pair of plate spring portions (44a and 44b) is placed on a first member (41) in such a manner as to sandwich the engagement body (43). The pair of plate spring portions (44a and 44b) bend in such a manner that a minimum dimension between the pair of plate spring portions (44a and 44b) is smaller than a dimension (length) of the engagement body (43). In a state where the engagement body (43) has gone beyond a minimum dimension position (53) between the pair of plate spring portions (44a and 44b) and the second member (42b) is being held at a predetermined position on the first member (41), the minimum dimension between the pair of plate spring portions (44a and 44b) is smaller than the dimension (length) of the engagement body (43), and both end portions (44a1, 44a3, 44b1, and 44b3), in a length direction, of the plate spring portions (44a and 44b) are supported by the first member (41).