Wedge-Guided Gripper Structure for Stable Axial Output Motion

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Solution Overview

Problem

The actuator in existing gripping devices is fixed to a fluid piston in a cantilevered manner, leading to a moment that hinders stable movement in the axial direction due to a reaction force from the flange portion.

Innovation Solution

A gripping device with an output member supported by an output member guide member, utilizing a drive unit that includes a spring and an operating portion to move the output member axially, and claw members guided by pin members and wedge grooves to stabilize movement, without requiring pressure fluid.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the actuator is fixed to the fluid piston rod in a cantilevered manner, then the structure is simple, but a moment is applied to the actuator that hinders stable movement of the fluid piston in the axial direction

Engineering Contradiction:
Improveactuator fixation structureVSAvoidstable movement of output member
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces an intermediary support structure (the support member with guide surfaces) between the actuator and the fluid piston rod. This intermediary component receives and redirects the reaction force from the flange portion, preventing it from creating a destabilizing moment on the actuator while allowing axial movement to proceed smoothly.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the force transmission path by separating the actuator mounting function from the piston rod connection function. The actuator is mounted on a support member that is distinct from the piston rod itself, allowing independent optimization of each component's function and reducing coupled interference between them.

Inventive Principle:
Principle #1Segmentation

2Force

If a conventional actuator with flange portion is used, then the gripping force can be applied, but the reaction force creates a moment that destabilizes the fluid piston movement

Engineering Contradiction:
Improvegripping forceVSAvoidstability of fluid piston movement
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The patent converts the harmful reaction force moment into a beneficial guiding function. The support member's guide surfaces are specifically designed to receive the reaction force from the flange portion and redirect it along the axial direction, transforming what was previously a destabilizing moment into a force that actually helps guide and stabilize the piston rod's movement.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Power

If pressure fluid (compressed air or oil) is used to drive the output member, then the gripping device can operate with sufficient force, but the device complexity and cost increase

Engineering Contradiction:
Improvegripping powerVSAvoiddrive system complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent replaces the pneumatic or hydraulic drive system with a purely mechanical spring-based system. The elastic member (spring) stores and releases mechanical energy to drive the output member, eliminating the need for compressors, hydraulic pumps, fluid reservoirs, and control valves associated with pressure fluid systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The elastic member serves multiple functions simultaneously: it stores energy, provides the driving force for gripping, and acts as a mechanical element that can be directly integrated into the structure. The spring-based system is self-contained and does not require external utility connections, making the device more autonomous and simpler.

Inventive Principle:
Principle #25Self-service

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 device enables stable movement of the output member and claw members, reducing the number of components and eliminating the need for pressure fluid, thereby enhancing stability and reducing costs.

Implementation Method 1

a spring 6 which is provided in a cylindrical hole 5a formed in the operating portion 5 and is configured to bias the output member 3 in a direction opposite to a direction in which the operating portion 5 is pressed into the hole 2

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

a first pin member 22 which is provided in the first claw member 16, the first pin member 22 being provided inside a first wedge groove 12 formed in an output member main body portion 4 of the output member 3

Methodology Applied
Scientific EffectWedge mechanism: Wedge

Data Source

PatentEP4721913A1Gripping device
Publication Date: 2026.04.08 KOSMEK LTD (JP)
  • EP4721913A1 patent drawingFigure 1A
  • EP4721913A1 patent drawingFigure 1B
  • EP4721913A1 patent drawingFigure 1C

AI summary

A gripping device includes: an output member (3); a first claw member (16); a second claw member (17); a first pin member (22) provided in the first claw member (16), the first pin member (22) being provided inside a first wedge groove (12) formed in the output member (3); a second pin member (26) provided in the second claw member (17), the second pin member (26) being provided inside a second wedge groove (13) formed in the output member (3); and an output member guide member (9) fixed to a housing (1), the output member guide member (9) being provided in an output member guide groove (8) formed in an end portion in the axial direction of an output member main body portion (4) of the output member (3).