Detachable Bushing Workpiece Holder for Dense Bore Layouts

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Solution Overview

Problem

Existing workpiece holders for machining elongate workpieces face issues with thermal distortion during brazing, limiting the number of workpieces that can be accommodated and resulting in reduced throughput due to the need for spaced bores and bushings.

Innovation Solution

A workpiece holder design where bushings are detachably fixed via positive and/or non-positive connections, allowing for closer spacing and eliminating thermal distortion, enabling higher throughput and easy replacement of worn bushings without affecting the retaining disk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If bushings are fixed by brazing, then the connection is strong and durable, but thermal distortion occurs and bores must be spaced far apart

Engineering Contradiction:
Improvebushing connection strengthVSAvoidholding disk distortion
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The bushing fixation is segmented into modular components: the holding disk remains separate from the bushings, which are attached via detachable connections (screws, clips, or press-fit mechanisms). This segmentation eliminates thermal distortion by avoiding brazing while maintaining secure attachment through mechanical means.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The harmful thermal process of brazing is extracted and replaced with a cold-joining method. The bushings are fixed using mechanical connections that do not generate heat, thereby preventing thermal distortion of the holding disk while preserving the strength and durability of the bushing attachment.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If bores are spaced far apart for brazing, then thermal distortion is avoided, but the number of workpieces that can be accommodated decreases

Engineering Contradiction:
Improveholding disk flatnessVSAvoidworkpiece throughput
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The holding disk is segmented into multiple zones with bores distributed throughout the disk area, not just at the periphery. This allows maximum utilization of the disk surface area while maintaining adequate spacing between bores to prevent thermal distortion during brazing operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bore arrangement transitions from a single circumferential ring to a multi-dimensional pattern distributed across the disk surface. This spatial optimization increases the number of accommodated workpieces while maintaining sufficient spacing between bores to avoid thermal distortion during brazing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Strength

If bushings are permanently brazed, then the connection is secure, but replacement of worn bushings requires replacing the entire workpiece holder

Engineering Contradiction:
Improvebushing attachment securityVSAvoidbushing replacement difficulty
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The bushing attachment system transitions from a static permanent connection (brazing) to a dynamic detachable connection that can be easily assembled and disassembled. Mechanical fasteners such as screws, clips, or press-fit mechanisms allow quick replacement of worn bushings while maintaining secure attachment during operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The design enables selective replacement of only the worn bushings while retaining the holding disk and other functional components. This extends the service life of the workpiece holder by allowing individual component replacement rather than requiring disposal of the entire assembly.

Inventive Principle:
Principle #34Discarding and recovering

4Productivity

If the holding disk diameter is increased to accommodate more workpieces, then throughput increases, but the size and complexity of the device increases

Engineering Contradiction:
Improveworkpiece capacityVSAvoidholding disk diameter
Core Design Contradiction:
ProductivityVSLength of stationary object

Solution Approach 1:

The holding disk utilizes its full surface area by distributing bores in a segmented pattern across the radius, not just at the outer circumference. This maximizes the number of workpieces that can be accommodated on disks of various sizes, improving productivity without requiring excessive disk diameter.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4039406A1Workpiece holder
Publication Date: 2022.08.10 LEISTRITZ PRODUKTIONSTECHNIK GMBH
  • EP4039406A1 patent drawingFigure 1~2
  • EP4039406A1 patent drawingFigure 3~4
  • EP4039406A1 patent drawingFigure 5~6

AI summary

Workpiece holder for receiving several elongated workpieces, in particular those to be machined at both ends, comprising a retaining disc (2) with several bores (3) arranged around the circumference, wherein a bushing (5) receiving a workpiece to be machined is received in each bore (3) and is fixed to the retaining disc (2), characterized in that each bushing (5) is detachably fixed in the bore (3) by means of at least one form-fit and/or force-fit connection.