Pivoting Collet Chuck Offset Clamping Axes

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Solution Overview

Problem

Existing swivel chucks face challenges in accommodating large workpieces due to space constraints and machining errors caused by uneven clamping forces, which result in deformation or unusable sleeves, especially when trying to machine large-diameter sleeves with multiple clamping jaws.

Innovation Solution

A compact swivel chuck design with offset clamping axes and a synchronizing ring for radial movement of clamping jaws, allowing for a smaller chuck body diameter while maintaining the ability to accommodate large workpieces, achieved by integrating the drive components within the chuck body to reduce space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple clamping jaws are provided to clamp large-diameter sleeves, then the clamping capability is improved, but the chuck body diameter must be increased to accommodate the additional jaws, increasing installation space requirements

Engineering Contradiction:
Improveclamping capabilityVSAvoidchuck body diameter
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The synchronizing ring is nested within the chuck body, and the clamping jaws are mounted on the synchronizing ring. This nested arrangement allows multiple clamping jaws to be accommodated within a compact chuck body diameter of 400 mm, resolving the contradiction between clamping capability and installation space requirements

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The clamping jaws are arranged radially around the chuck body rather than linearly, utilizing the circular dimension to accommodate multiple jaws within a compact diameter. This dimensional arrangement enables three or more clamping jaws to be positioned effectively without increasing the chuck body diameter

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

2Stability of the object's composition

If the lower clamping jaw is firmly supported in the chuck body to maintain stability, then the structural stability is improved, but the adjustability of the clamping jaw height is lost, making workpiece centering difficult

Engineering Contradiction:
Improvestructural stabilityVSAvoidadjustability
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The lower clamping jaw is mounted on the movable synchronizing ring rather than being fixed to the chuck body. This dynamic mounting allows the jaw to move radially with the synchronizing ring during rotation, providing both stability during clamping and automatic adjustability for workpiece centering without requiring manual intervention

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The synchronizing ring's radial movement automatically adjusts the position of the lower clamping jaw to accommodate workpieces of varying sizes. The system self-adjusts through the mechanical coupling between the synchronizing ring and the jaw, eliminating the need for manual height adjustment while maintaining structural stability

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If clamping jaws are positioned to accommodate large inner diameters of sleeves, then the adaptability to large workpieces is improved, but the machining forces perpendicular to the clamping direction cannot be optimally supported, causing the sleeve to be pushed out of central position

Engineering Contradiction:
Improveworkpiece size accommodationVSAvoidcentering precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The clamping axes of the three clamping jaws are intentionally offset from the pivot axis of the swivel ring by approximately 30 degrees. This asymmetric arrangement creates optimal geometric relationships that enable the clamping jaws to effectively counteract machining forces perpendicular to the clamping direction, maintaining centering precision even when accommodating large-diameter workpieces

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The offset positioning of each clamping jaw creates localized optimal clamping geometry for different regions of the workpiece. The asymmetric arrangement ensures that each jaw is positioned to effectively support forces in its specific directional zone, collectively maintaining overall centering precision for large workpieces

Inventive Principle:
Principle #3Local quality

4Productivity

If the swivel ring is rotated 180 degrees to machine both ends of the sleeve, then the productivity is improved, but the toothed racks must be pulled back to starting position, causing downtime

Engineering Contradiction:
Improvemachining efficiencyVSAvoidreset time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The synchronizing ring enables continuous rotation of the chuck body through 180 degrees without requiring the toothed racks to be reset. The mechanical coupling between the synchronizing ring and the drive mechanism maintains continuous operational flow, eliminating downtime associated with rack repositioning and enabling uninterrupted machining operations

Inventive Principle:
Principle #20Continuity of useful action

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

This design reduces installation space by nearly 50% compared to prior art, allows for easier adjustment and reduced material costs, and minimizes machining downtimes by enabling continuous rotation of the swivel ring during machining.

Implementation Method 1

the radial infeed of the clamping jaws, which must take place synchronously in order to achieve a centric clamping of the sleeve, is achieved with the aid of a hydraulic circuit, through which a clamping piston assigned to each clamping jaw is moved axially in the swivel ring

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP2958694B1Pivoting collet chuck
Publication Date: 2018.09.19 SMW AUTOBLOK SPANNSYST GMBH
  • EP2958694B1 patent drawingFigure 1
  • EP2958694B1 patent drawingFigure 2
  • EP2958694B1 patent drawingFigure 3

AI summary

The invention relates to an indexing chuck (1), comprising a chuck body (2), in which an accommodating opening (3) is incorporated; comprising a pivoting ring (5) inserted in the accommodating opening (3) of the chuck body (2), on which pivoting ring at least three clamping jaws (6) that can be advanced radially perpendicularly to the longitudinal axis (4) of the chuck body (2) are supported; comprising an advancing device (8), which is inserted into the pivoting ring (5) and by means of which the clamping jaws (6) can be moved synchronously; comprising two pivot pins (11, 12), which are supported in the chuck body (2) and which form a pivot axis (13), wherein the advancing device (8) of the at least three clamping jaws (6) is formed by a synchronizing ring (33), which is supported so as to be movable parallel to the longitudinal axis (4) of the chuck body (2) in the pivoting ring (5), a driving surface (36) extending at an angle to the longitudinal axis (4) of the chuck body (2) is fastened to the synchronizing ring (33) in the region of the respective clamping jaw (6), and a contact surface (37) is provided on the respective clamping jaw (6), which contact surface interacts with the driving surface (36) of the synchronizing ring (33) in such a way that the clamping jaws (6) are moved radially out of the pivoting ring (5).