Chuck Release Bolt Safety Mechanism

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Solution Overview

Problem

The existing wedge bar chucks for machine tools are complex and expensive due to their numerous components, which complicates the structure and increases costs.

Innovation Solution

A chuck design where the release bolt is fixed axially and rotates within a retaining bore, engaging with a control pin to move the wedge bar beyond its outer working position for jaw changes, allowing for a one-piece wedge bar and a safety mechanism that prevents unintended re-engagement, simplifying the structure and reducing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional wedge bar mechanism with multiple components is used, then the chuck can achieve reliable jaw clamping and release, but the structure becomes complex and costly

Engineering Contradiction:
Improvejaw clamping and release reliabilityVSAvoidmechanism structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The release bolt integrates multiple functions into a single component: it acts as both the actuating element for jaw release and as part of the safety mechanism. The control groove and engagement elements are incorporated directly into the release bolt, eliminating the need for separate coupling attachments and reducing the total component count while maintaining reliable jaw clamping and release functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The release bolt serves multiple purposes simultaneously: it transmits rotational motion to move the wedge bar, provides safety interlocking through its engagement elements, and controls the jaw release process. This multi-functional design reduces device complexity by consolidating what would traditionally require multiple separate components

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If a two-part wedge bar design with coupling attachment is used, then jaw change is enabled, but the number of components increases and costs rise

Engineering Contradiction:
Improvejaw change capabilityVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The release bolt merges the actuating function and safety function into one component. The control groove that transmits motion and the engagement elements that provide safety interlocking are integrated into the single release bolt structure, eliminating the need for separate coupling attachments and reducing component count while maintaining jaw change capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control groove is segmented into different sections (first groove section for wedge bar movement, second groove section for safety positioning) that perform different functions at different stages of the rotation, enabling complex motion control within a single component structure

Inventive Principle:
Principle #1Segmentation

3Reliability

If safety mechanism components are added to prevent unintended re-engagement, then operational reliability improves, but device complexity increases

Engineering Contradiction:
Improveoperational reliabilityVSAvoidsafety mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The safety mechanism is integrated into the release bolt structure itself through engagement elements that interact with corresponding features on the wedge bar and chuck body. This eliminates the need for separate safety components while providing reliable prevention of unintended re-engagement through the interlocking geometry of the engagement elements

Inventive Principle:
Principle #5Merging (Combining)

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 simplifies the chuck by allowing one-piece wedge bars and enhances operational reliability by ensuring precise control over jaw changes and clamping actions, reducing the complexity and cost of the mechanism.

Implementation Method 1

The wedge bars have on their front end face a helical toothed rack, which engages with a corresponding toothing of a clamping jaw inserted into the corresponding guide groove in order to convert a movement of the wedge bars into a radial movement of the clamping jaws

Methodology Applied
Scientific EffectHelical gearing: Gear

Implementation Method 2

An end section of the release bolt pointing into the interior of the chuck body rotatably engages in a receiving bore of the associated wedge bar, with a control groove being formed in the peripheral surface of the end section, which engages with a control pin held in the wedge bar and protruding into the receiving bore

Methodology Applied
Scientific EffectMechanical engagement: Mechanical Force

Data Source

PatentEP3191245B1Chuck
Publication Date: 2018.08.29 SCHUNK GMBH & CO KG
  • EP3191245B1 patent drawingFigure 1
  • EP3191245B1 patent drawingFigure 2
  • EP3191245B1 patent drawingFigure 3

AI summary

The invention relates to a chuck comprising a chuck body (1), a number of guide points for chuck jaws running radially in relation to the chuck axis, a wedge bar mechanism for actuating the chuck jaws having a number of wedge bars (5) which are guided in wedge bar pockets (6) of the chuck body (1) running transversely in relation to the guide grooves (3), and which can be adjusted by a drive in a working region between an inner working position, corresponding to an inner chuck position of the chuck jaws (4), and an outer working position, corresponding to an outer chuck position of the chuck jaws (4). One safety mechanism is assigned to each wedge bar (5). This comprises a release bolt (9) which is rotatably arranged about its longitudinal axis, in a holding borehole (11) of the chuck body (1) that extends in the longitudinal direction of the corresponding wedge bar (5). An end section (9a) of the release bolt (9) leading into the chuck body (1) rotatably engages in a receiving borehole (13) of the associated wedge bar (5), wherein a control groove is formed in the peripheral surface of the end section (9a), said control groove (14) being engaged with a control pin (15), which is held in the wedge bar (5) and projects into the receiving borehole (13), in such a way that a rotation of the release bolt (9) from its starting position into its release position causes the wedge bar (5) to be pulled away beyond the outer working position into a jaw change position to such an extent that a row of teeth (7) of the wedge bar (5) are positioned outside the region of the guide groove (3), thereby permitting a chuck jaw (4) to be removed from the guide groove (3). The safety mechanism comprises locking means which prevent the wedge bar (5) from being moved from its jaw change position back into its outer working position by rotating the release bolt, without a chuck jaw (4) being inserted into the guide groove (3).