Dual Bayonet Collet Coupling for Precise Tool Clamping
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Solution Overview
Problem
Modern machine tools face challenges in achieving precise and secure clamping of tools due to high-speed rotation, which demands high concentricity and quick setup times, while existing clamping devices often suffer from eccentricity errors and complex setup procedures.
Innovation Solution
A clamping device with a draw-back collet and coupling element utilizing two bayonet locks for simultaneous engagement, allowing for quick and secure tool clamping with high concentricity, featuring a tension sleeve and adjustable force clamping system, and concentricity adjustment mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single bayonet lock is used to couple the draw-back collet and coupling element, then the device complexity is reduced, but the concentricity precision and clamping reliability deteriorate due to potential eccentricity errors
Solution Approach 1:
The single bayonet lock is segmented into two separate bayonet locks (first and second bayonet locks) that operate independently. Each lock has its own locking elements and grooves, allowing them to engage separately to progressively reduce eccentricity errors while maintaining manageable device complexity.
Solution Approach 2:
The first bayonet lock is engaged in a preliminary action to establish initial concentricity alignment between the draw-back collet and coupling element. This preliminary alignment prepares the system for the second bayonet lock engagement, which then secures the precise concentric position, thereby achieving high manufacturing precision through staged operations.
2Force
If a threaded connection is used to pull the draw-back collet into the base body, then the clamping force can be adjusted, but the setup time increases due to the complex screwing operation
Solution Approach 1:
The traditional threaded mechanical connection is substituted with a bayonet lock mechanism that uses rotational engagement instead of screwing. This replacement maintains the ability to apply and adjust clamping force through the draw-back action while dramatically reducing setup time by eliminating the multi-turn screwing operation.
Solution Approach 2:
The coupling mechanism transitions from a static threaded connection to a dynamic bayonet lock that can be quickly engaged and disengaged through rotational movement. This dynamic coupling allows for rapid tool changes while maintaining secure clamping force through the draw-back collet mechanism.
3Adaptability or versatility
If the collet is divided into many tongues by axial slots, then the clamping adaptability improves, but the structural strength deteriorates due to reduced material continuity
Solution Approach 1:
The collet combines multiple materials with complementary properties: the body is made of high-strength steel for structural integrity, while the tongues incorporate elastic material sections that provide clamping force. This composite construction maintains structural strength despite the slots by using material composition rather than pure geometric continuity.
Solution Approach 2:
The collet exhibits local quality variations where the tongue regions have different mechanical properties than the body. The tongues are designed with specific elastic characteristics to provide clamping force, while the body maintains high strength. This localized differentiation allows the slots to exist without compromising overall structural strength.
4Manufacturing precision
If a bayonet lock with locking elements in grooves is used, then the concentricity precision improves, but the device complexity increases due to additional locking components
Solution Approach 1:
The two bayonet locks are merged into a coordinated system where the first and second locks work together to achieve concentricity. By combining multiple locking actions into a unified coupling process, the system achieves high precision without proportionally increasing complexity, as the locks share common structural elements and engagement sequences.
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 fast and precise tool clamping with high concentricity, reducing setup times and maintaining tool longevity by ensuring even load distribution and precise alignment, suitable for various machine tools and small batch production.
Implementation Method 1
the draw-back collet is pulled into the receiving opening of the base body by turning the coupling element - whereby an inner diameter of the cylindrical inner shell of the draw-back collet is reduced and a shank of the tool is fastened with a radial press fit
Implementation Method 2
The locking of the bayonet lock - and thus the coupling of the draw-back collet and the coupling element - takes place by pushing and twisting the locking elements of the draw-back collet into the grooves of the coupling element
Implementation Method 3
If the - slotted - collet is pressed with its outer cone into the inner cone of the base body, the tool inserted with its cylindrical shank into the collet or the tool received with its cylindrical shank in the cylindrical inner surface of the collet is radially machined/clamped
Data Source
Figure 1a~1b
Figure 2
Figure 3a~3d
AI summary
The invention relates to a clamping device for a tool or workpiece with a draw-type collet and a coupling element, a draw-type collet for a clamping device, a coupling element for a clamping device, and a method for preparing a clamping device for a tool or workpiece with a draw-type collet and a coupling element.According to the invention, a clamping device for a tool or workpiece with a drawbar and a coupling element has a first and a second bayonet lock, by means of which the drawbar can be locked and clamped against the coupling element, wherein the first and the second bayonet lock can be engaged simultaneously, whereby the drawbar can be locked against the coupling element using the first bayonet lock and the drawbar can be clamped against the coupling element using the second bayonet lock.