Low-Profile Chuck Layout for Accurate Multi-Jaw Workpiece Centering
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Solution Overview
Problem
Existing chucks face inaccuracies and unpredictable clamping forces due to motion clearances, especially when handling workpieces with non-symmetric contours, leading to incorrect positioning and processing.
Innovation Solution
A chuck design with linearly movable piston rods or threaded spindles perpendicular to the centering axis, combined with a synchronizer ring and compensatory rockers, allows for independent compensation of clamping jaw movements and synchronization of actuating forces, ensuring precise alignment and clamping without increasing the chuck's constructional height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If motion clearance is provided between clamping jaws and drive components, then the clamping jaws can accommodate workpieces with different dimensions and contours, but positioning accuracy and clamping force consistency deteriorate
Solution Approach 1:
The rocker acts as a feedback mechanism that detects when all clamping jaws have made contact with the workpiece. When contact is established, the rocker pivots to signal the drive means to generate full clamping force, ensuring accurate positioning while accommodating various workpiece geometries
Solution Approach 2:
The rocker serves as an intermediary element between the clamping jaws and the drive means. It mediates the motion sequence by temporarily decoupling the clamping jaws from the drive force until all jaws are properly positioned, thereby eliminating the harmful effect of motion clearance
2Adaptability or versatility
If motion clearance is provided between drive components, then the system can handle workpieces with varying dimensions, but clamping force predictability worsens
Solution Approach 1:
The system performs preliminary positioning action through the rocker mechanism before applying full clamping force. The rocker ensures all clamping jaws are correctly positioned and contact the workpiece beforehand, making the subsequent clamping force application predictable and reliable
Solution Approach 2:
The rocker provides feedback on the positioning status of all clamping jaws. Only when the rocker indicates proper positioning does the drive means apply full clamping force, ensuring both adaptability to different dimensions and predictability of the clamping force
3Device complexity
If drive means are arranged coaxially with the chuck body axis, then the clamping mechanism is simplified, but the constructional height increases requiring additional machine tool space
Solution Approach 1:
The drive means are arranged perpendicular to the chuck body axis, changing the spatial dimension from axial to radial arrangement. This dimensional change reduces the constructional height while maintaining the functional simplicity of the clamping mechanism through the rocker-based motion sequence control
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 ensures accurate and repeatable positioning of workpieces coaxially with the centering axis, maintaining low constructional height and eliminating the need for additional space, while ensuring all clamping jaws engage simultaneously for consistent clamping force application.
Implementation Method 1
a rocker disposed between two adjacent clamping jaws, respectively, by means of which a movement compensation between the two clamping jaws is effected
Implementation Method 2
the axial feed movement of the drive means is transmitted to the respective clamping jaws via corresponding helical gearings, inclined surfaces or a grab-hook connection
Implementation Method 3
the drivers are drivingly coupled with an axially movable pressure piston via a coupling ring so that the actuating force of the pressure piston acts upon the driver
Data Source
AI summary
A chuck (1) is provided by means of which workpieces (2) are supported individually for machining by a machine tool (3) and aligned coaxially to a centering axis (4), which serves as a reference for machining the workpiece (2) by the machine tool (3), having a chuck body (5), having at least four clamping jaws (6, 7, 8, 9) that are radially movably mounted on the chuck body (5) and are arranged in pairs in an X or Y plane and by means of which the workpiece (2) is held during the machining process to be aligned with respect to the centering axis (4), and having a pull piston (45) that is mounted in or at the chuck body (5) so as to be linearly movable and which is drivably coupled to a respective clamping jaw (6, 7, 8, 9) such that during the linear movement of the pull piston (45) the clamping jaws (6, 7, 8, 9) are radially fed in the direction of the workpiece (2) to be clamped or moved away from same in a synchronous manner, wherein the pull piston (45) is arranged coaxially with respect to the centering axis (4) inside the chuck body (5) and is axially actuated by one or more drive means (12, 13, 52, 53), on the one hand aiming at adjusting the compensatory movements between two adjacent clamping jaws running perpendicular to one another (6, 7, 8, 9) irrespective of their feed movement and operative contact with the workpiece (2) to be clamped, and on the other hand aiming at the constructional height of such chuck (1) being as small as possible. This aim is achieved in that each drive means (12, 13, 52, 53) has a linearly movable piston rod (26) or threaded spindle (55), whose respective longitudinal axis (26′ or 55′) is arranged to be perpendicular to the centering axis (4). (FIG. 1)