Compact Tool Holder Clamping Layout for Short-Axis Turrets

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Solution Overview

Problem

Existing clamping devices for machine tools are too long and not suitable for use in tool turrets with limited axial space, leading to stress on rotary bearings and inefficiencies in tool changing operations.

Innovation Solution

A clamping device with a hydraulic actuator and motion transferring mechanism that allows the drawbar to move between releasing and locking positions without rotating parts, reducing stress on rotary bearings and enabling compact design for use in tool turrets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a clamping device with a hydraulic actuator and motion transferring mechanism is used, then the axial length of the clamping device is reduced, but the device complexity increases

Engineering Contradiction:
Improveaxial length of clamping deviceVSAvoidcomplexity of motion transferring mechanism
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The motion transferring mechanism is arranged concentrically around the spindle, with components nested within each other radially. The actuating member is surrounded by the first drawbar, which is surrounded by the second drawbar, creating a compact nested structure that reduces axial length while containing all necessary functional elements within a limited radial space.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention transitions from a primarily axial arrangement of components to a concentric radial arrangement. The motion transferring mechanism uses radial positioning and concentric nesting to achieve compactness in the axial direction, effectively moving the design problem from one dimension (axial) to another (radial).

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

2Adaptability or versatility

If the clamping device has a long axial extent, then it can accommodate all necessary components, but it cannot be used in tool turrets with limited axial space

Engineering Contradiction:
Improvesuitability for tool turret applicationVSAvoidaxial extent of clamping device
Core Design Contradiction:
Adaptability or versatilityVSLength of moving object

Solution Approach 1:

Multiple functional components are nested concentrically around the spindle: the actuating member is surrounded by the first drawbar, which is surrounded by the second drawbar. This nested arrangement allows all necessary clamping and actuation components to be accommodated within a compact axial envelope suitable for tool turret applications.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The clamping device uses dynamic elements including a movable actuating member that can slide axially, drawbars that move between retracted and advanced positions, and engagement members that can rotate or shift to lock or release the tool holder. These dynamic components enable compact packaging while maintaining full functionality.

Inventive Principle:
Principle #15Dynamics

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

The solution enables efficient automatic tool changing with reduced stress on rotary bearings, allowing for smaller or longer-lasting bearings and improved operational efficiency in machine tools.

Implementation Method 1

a hydraulic actuator for moving the actuating member axially in relation to the spindle, the hydraulic actuator being arranged in the housing and comprising a cylinder housing and a piston member

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP4108368B1Clamping device for tool holder
Publication Date: 2023.12.06 SANDVIK COROMANT
  • EP4108368B1 patent drawingFigure 1~2
  • EP4108368B1 patent drawingFigure 3a
  • EP4108368B1 patent drawingFigure 3b~3c

AI summary

A clamping device for releasably holding a tool holder shank (81), comprising: - a spindle (2) rotatably mounted inside a housing (3); - a drawbar (8) axially moveable in a bore (5) in the housing between an advanced releasing position and a retracted locking position; - engagement members (20) moveable under the effect of the drawbar into locking engagement with the tool holder shank; - an actuating member (13) slidably mounted to the spindle; - a motion transferring mechanism (30) for transferring an axial movement of the actuating member into a movement of the drawbar; and - a cylinder housing (60) and an associated piston member (70) for moving the actuating member in relation to the spindle. The cylinder housing (60) is arranged in the housing (3) in an axially floating manner. The actuating member (13) is rotatable in relation to the cylinder housing (60) and the piston member (70) together with the spindle (2).