Automatic Tool-Holder Locking Device for CNC Lathes

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Solution Overview

Problem

Existing methods for replacing tool-holders on CNC machines and other machining tools require frequent manual intervention, leading to increased production costs due to downtime, awkward operations, and exposure to lubricants and refrigerants, with no efficient means for automatic centring and positive locking.

Innovation Solution

An automatic device with a pawl mechanism using a motorized planetary gear reducer and proximity sensors allows for remote operation, enabling quick and precise locking and unlocking of tool-holders, with automatic centring along multiple axes, reducing operator strain and contamination risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If manual replacement of tool-holders is used, then device complexity is reduced, but productivity decreases due to frequent downtime and set-up times

Engineering Contradiction:
Improveproduction efficiencyVSAvoidlocking device complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The locking device automatically performs centring and locking operations without requiring manual intervention. The system uses sensors to detect tool-holder positions and automatically activates motors to move pawls for centring and locking, enabling the device to service itself and eliminating the need for operator intervention during tool replacement.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces manual mechanical operations with an automated electromechanical system. Motors drive pawls through leadscrews to perform centring and locking actions that previously required manual operation of handles or spanners, substituting mechanical manual control with automated motorized control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If operator performs manual locking operations, then ease of operation is reduced due to awkward positions and repeated strain, but device complexity is minimized

Engineering Contradiction:
Improveoperator convenienceVSAvoidlocking mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The locking mechanism automatically performs all locking and centring operations without requiring operator intervention. The system detects tool-holder installation and automatically activates the appropriate motors to position pawls and secure the tool-holder, eliminating the need for operators to perform repeated manual locking actions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces motors and sensors as intermediary elements between the operator and the locking mechanism. Instead of directly operating handles or spanners, the operator simply installs the tool-holder and the automated system mediates the locking process, eliminating awkward positions and physical strain.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If frequent tool-holder replacement is performed manually, then adaptability is improved, but loss of time increases due to downtime and set-up operations

Engineering Contradiction:
Improvetool replacement flexibilityVSAvoiddowntime
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The system automatically performs centring and locking operations immediately upon tool-holder installation, eliminating the time required for manual set-up operations. The automated detection and actuation system reduces the replacement cycle time while maintaining full adaptability for frequent tool changes.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent positions pawls in preliminary centring positions automatically upon tool-holder installation, before final locking occurs. This preliminary automated centring action eliminates the time previously required for manual adjustment and positioning operations.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If automated locking device is implemented, then reliability is improved through consistent positioning, but device complexity increases due to additional components

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsystem component count
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces manual positioning operations with motorized actuators that drive pawls through leadscrews. This substitution provides consistent, repeatable positioning accuracy controlled by the motor system, eliminating variability in manual operations while using relatively simple electromechanical components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 significantly reduces downtime and production costs by enabling rapid, precise, and automated replacement of tool-holders, minimizing operator exposure to hazardous substances and eliminating strenuous manual operations, while ensuring high reliability and resistance over time.

Implementation Method 1

a motor with a planetary gear reducer (46), fitted with a shaft (48)

Methodology Applied
Scientific EffectPlanetary gear mechanism: Epicyclic Gearing

Implementation Method 2

said body (30), in which an exposed face (32) has a quadrangular extension, defines a threaded leadscrew, with internal trapezoidal thread

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 3

The automatic locking device further comprises at least two proximity sensors (54), provided for each tool-holder (12), suitable to detect the stroke performed, and therefore the position reached by the pawls (18)

Methodology Applied
Scientific EffectProximity sensing:

Data Source

PatentEP3403760B1Automatic device for locking tool-holders on lathes and machine tools
Publication Date: 2020.02.19 ALGRA SPA
  • EP3403760B1 patent drawingFigure 1
  • EP3403760B1 patent drawingFigure 2~3
  • EP3403760B1 patent drawingFigure 4~6

AI summary

An automatic device for locking of tool holders (12) on lathes and machinery performing machining by chip removal, particularly suitable to be used on multi-spindle and single spindle CNC lathes, on transfer machines, milling centres of any kind and, in general, on all types of machine tools which perform machining by chip removal, comprises a support body (14) anchored to the machine tool and surmounted by a plate (16), said device comprises, for each of said tool-holders (12), a pawl (18) provided with a female truncated-cone recess (24), cooperating with a nut screw (36) and moved automatically vertically to engage in contact with a truncated cone collar appendage (40) made in a recess (38) in the rear (12'). The movement in the vertical direction of the pawls(18) is produced by means of individual motors (46), equipped with a shaft (48) which protrudes from their lower face and engages to the upper end of said nut screw (36).