Method of disassembling a cold head and lifting-up jig

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Solution Overview

Problem

The disassembly and maintenance of cold heads in cryocoolers are challenging due to their movable nature and limited space, making it difficult to handle heavy components and perform operations efficiently.

Innovation Solution

A method involving a lifting-up jig system that includes a displacer drive unit and a lifting-up jig with a rotatable bolt, allowing for the axial lifting of the displacer drive unit and displacer, facilitating easier disassembly and assembly by reducing manual labor and accommodating space constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If manual disassembly of cold head components is performed, then maintenance can be carried out, but it is difficult to handle heavy components and perform operations efficiently due to limited space and movable nature of the cold head

Engineering Contradiction:

Improvemaintenance efficiencyVSAvoidhandling difficulty

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

A lifting-up jig is introduced as an intermediary tool between the maintenance personnel and the heavy cold head components. The jig includes a lifting-up bolt that engages with a lifting-up bolt hole in the displacer drive unit, allowing operators to mechanically lift heavy components without direct manual handling, thus improving both ease of operation and maintenance efficiency

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The lifting-up bolt hole is pre-provided in the displacer drive unit, and the lifting-up jig is prepared in advance. This preliminary preparation allows for quick engagement and lifting operations during maintenance, eliminating the need for complex manual handling procedures and improving overall maintenance productivity

Inventive Principle:

Principle #10Preliminary action

2Ease of repair

If the cold head is made movable relative to the sleeve for maintenance access, then the cold head can be separated from the sleeve, but handling and positioning become more difficult in limited spaces

Engineering Contradiction:

Improvemaintenance accessibilityVSAvoidhandling difficulty

Core Design Contradiction:

Ease of repairVSEase of operation

Solution Approach 1:

The lifting-up jig acts as a mediator that provides controlled movement of the cold head components. By engaging the lifting-up bolt with the lifting-up bolt hole, the jig enables precise positioning and handling of the movable cold head components, making maintenance accessible while controlling the handling difficulty

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cold head is designed to be movable relative to the sleeve, and the lifting-up jig provides dynamic control over this movement. The lifting-up bolt can be engaged and disengaged to control the position of the cold head, allowing maintenance operations while managing the complexity of handling movable components

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11278994B2Method of disassembling a cold head and lifting-up jig

Publication Date: 2022.03.22 SUMITOMO HEAVY IND LTD

AI summary

Provided is a method of disassembling a cold head provided with a displacer that extends in an axial direction, a cylinder that accommodates the displacer, and a displacer drive unit that is fastened to the cylinder and is connected to the displacer such that the displacer is driven in the axial direction, the method including mounting a lifting-up jig onto the displacer drive unit, unfastening the displacer drive unit and the cylinder from each other, and operating the lifting-up jig such that the displacer drive unit is lifted up from the cylinder together with the displacer.