Tool Holder Clamping with Radial Actuation in Tight Axial Space
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Solution Overview
Problem
Existing clamping mechanisms for tool holders in machine tools are bulky and require manual operation, making them unsuitable for automatic tool change applications and limited by axial space constraints in tool turrets.
Innovation Solution
A compact clamping device actuated via a member introduced non-parallel to the longitudinal axis, utilizing inclined surfaces for axial displacement and self-locking mechanisms, allowing for automated operation without manual intervention and efficient force distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If manual clamping mechanisms (cam shaft, wedges) are used, then clamping function is achieved, but device size becomes bulky and requires manual operation
Solution Approach 1:
The patent replaces traditional manual mechanical clamping mechanisms (cam shafts, wedges) with a hydraulic actuator system. The hydraulic piston converts hydraulic pressure into linear motion, which drives the drawbar to clamp the tool holder. This substitution enables automated operation while reducing the overall device volume compared to manual mechanisms.
Solution Approach 2:
The invention uses a hydraulic piston and fluid pressure system to actuate the drawbar. Hydraulic fluid is introduced into the piston chamber, generating force that moves the drawbar axially for clamping and releasing the tool holder. This hydraulic actuation system provides automated control and compact design, eliminating the need for manual cam shaft rotation or wedge manipulation.
2Length of stationary object
If traditional clamping mechanisms are used, then clamping force is sufficient, but axial space requirement is excessive
Solution Approach 1:
The patent changes the actuation direction from axial (parallel to tool holder axis) to radial (perpendicular to tool holder axis). The hydraulic piston is arranged radially, and its linear motion is transmitted through a conversion mechanism to produce axial drawbar movement. This dimensional change allows compact axial space while maintaining sufficient clamping force through the force transmission mechanism.
Solution Approach 2:
The invention nests multiple functional components within a compact axial space. The hydraulic piston, drawbar, and tool holder are arranged concentrically along the radial direction, with the drawbar moving axially within the bore. This nested arrangement minimizes axial length while accommodating all necessary clamping components, achieving reliable clamping in a compact configuration.
3Productivity
If manual actuation is used, then device structure is simple, but operation efficiency is low
Solution Approach 1:
The patent replaces manual mechanical actuation with an automated hydraulic actuation system. The hydraulic piston responds to hydraulic pressure signals to automatically execute clamping and releasing operations, eliminating manual intervention. This increases tool change speed and productivity, despite the added complexity of the hydraulic system, which is justified by the automation benefits.
Solution Approach 2:
The hydraulic actuator system operates autonomously in response to hydraulic pressure control signals. The piston automatically extends and retracts to clamp and release the tool holder without requiring manual operation of cam shafts or other mechanical actuators. This self-service capability enables automated tool changing, significantly improving productivity in CNC machining centers.
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
Enables compact design, automated operation, and self-locking functionality, suitable for automatic tool change applications while minimizing space requirements and ensuring reliable clamping and release mechanisms.
Implementation Method 1
a movement of the actuator in the first direction results in that a pressure is applied by the first locking pressure applying surface on the first locking pressure receiving surface of the drawbar. This pressure will have a component in the axial direction of the bore, such that the drawbar is displaced axially therein
Implementation Method 2
Sliding contact between the respective surfaces is achieved over a large area during movement of the actuator, such that the applied force is distributed in a good way
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
The invention relates to a clamping device (1) for releasably holding a tool holder shank (33). The device comprises a housing (2), a drawbar (6) being mounted reciprocally movable inside a bore (5) in the housing, and an actuator (8). An aperture extends along an actuator axis (A) and is delimited by an aperture housing surface (24) and a drawbar groove (25). A first locking pressure applying surface (10) on the actuator acts upon a first locking pressure receiving surface (11) in the drawbar groove to effectuate a displacement of the drawbar (6) when the actuator (8) is moved along the actuator axis (A) in a first direction (D), resulting in clamping of the tool holder shank (33).