Integrated Gripper Case for Larger Piston Diameter

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Solution Overview

Problem

Conventional grippers face challenges in compactness and cost due to the requirement of a thicker cylindrical member and multiple components, which restrict the increase in piston diameter and increase component costs.

Innovation Solution

A gripper design that eliminates the need for an annular recessed groove in the first case, allowing for a thinner peripheral wall and a larger piston diameter, with the first case processed as a single component and featuring a cylindrical outer peripheral wall, enabling a compact shape and reduced component count.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If an annular recessed groove is formed on the inner peripheral surface of the cylindrical member, then the piston can be housed inside the cylindrical member, but the thickness of the peripheral wall must be larger than the depth of the groove, making it difficult to make the first case compact while increasing the outside diameter of the piston

Engineering Contradiction:
Improveoutside diameter of pistonVSAvoidcompactness of first case
Core Design Contradiction:
Volume of moving objectVSShape

Solution Approach 1:

The invention extracts and eliminates the annular recessed groove from the cylindrical member structure. By removing this groove, the peripheral wall thickness constraint is eliminated, allowing the first case to be made more compact while accommodating a larger diameter piston without requiring the wall to be thick enough to contain a groove of the necessary depth.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of forming a recessed groove inward from the inner peripheral surface to accommodate the piston, the invention inverts the approach by having the piston fit into the cylindrical member without requiring an inward groove. The sealing and positioning functions are achieved through alternative means that do not consume peripheral wall thickness.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If the cylindrical member, cap member, and stopper ring are used as separate components, then the piston can be incorporated into the body case, but the number of components and component cost are increased

Engineering Contradiction:
Improvepiston incorporation reliabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the cylindrical member, cap member, and stopper ring into an integrated first case component. The single-piece construction eliminates the need for separate components while maintaining the functional integrity of piston incorporation, sealing, and positioning through integrated structural features.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The first case is designed as a multi-functional integrated component that simultaneously performs the functions of the cylindrical member (housing), cap member (closure), and stopper ring (positioning). This universal component achieves multiple functions in one piece, reducing component count while maintaining reliability.

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

Data Source

PatentEP3513917B1gripper
Publication Date: 2024.05.29 KITAGAWA IRON WORKS CO LTD
  • EP3513917B1 patent drawingFigure 1
  • EP3513917B1 patent drawingFigure 2
  • EP3513917B1 patent drawingFigure 3

AI summary

The present invention provides a compact and low-cost gripper which allows an outside diameter of a piston to be increased. Provided is a gripper comprising: a body case having, at one end, a cylinder part having a cylinder chamber which houses a piston so as to slide the piston along a central axis of the piston, and having, at the other end, a plurality of guide parts formed at regular intervals around the center axis and extending in a direction orthogonal to the center axis; a plurality of master jaws, on which top jaws can be removably mounted, guided by each of the guide parts; and a plunger having a plurality of interconnecting means which are respectively interconnected with each of the master jaws and slides along the central axis associated with a sliding operation of the piston, wherein: the gripper is configured such that each of the interconnecting means moves, by a sliding operation of the plunger, each of the master jaws in either direction along each of the guide parts, so as to cause each of the top jaws to grip a workpiece or to release the gripped workpiece; the body case has a first case which is provided on one side of the central axis and formed so that the cylinder chamber opens to the other side of the central axis, and a second case which is provided on the other side of the central axis and has each of the guide parts; and the second case is fixed to the first case so as to cover an opening of the first case on a side of the second case.