Transfer Plunger Tapping Mechanism for Sticky Powder Metering

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Solution Overview

Problem

Existing devices for dosing powdery filling materials, especially when dealing with sticky products, face issues of powder sticking to transfer plungers, leading to metering inaccuracies, product carryover, and contamination due to uneven breaking off of powder compacts during the transfer process.

Innovation Solution

The introduction of an additional drive unit that accelerates the transfer plunger in the opposite direction to the transfer direction, providing a vehement impulse to overcome adhesive forces and ensure reliable detachment of powder compacts, allowing them to fall freely into the capsule.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the transfer plunger is held in position just above the lower part segment to allow capsule transport to move further, then the capsule positioning is improved, but the powder compacts stick to the transfer plunger and do not fall into the capsule base

Engineering Contradiction:
Improvecapsule positioning precisionVSAvoidpowder transfer reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The transfer plunger performs periodic tapping movements in addition to its main transfer stroke. These periodic tapping actions create vibrations that prevent powder compacts from sticking to the transfer plunger surface, ensuring reliable powder transfer while maintaining the holding position for capsule positioning.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The transfer plunger is equipped with a tapping mechanism that generates mechanical vibrations during the transfer process. These vibrations reduce adhesion between the powder compacts and the transfer plunger, allowing the powder to detach and fall into the capsule base reliably while the plunger remains positioned above the lower part segment.

Inventive Principle:
Principle #18Mechanical vibration

2Reliability

If the transfer plunger is accelerated in the opposite direction to the transfer direction, then the tear-off force overcomes adhesive forces and powder detachment is improved, but the device complexity increases due to the additional drive unit

Engineering Contradiction:
Improvepowder detachment reliabilityVSAvoiddrive system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The tapping drive unit is integrated into the existing transfer plunger mechanism, combining the transfer function and the detachment function into a single integrated assembly. This reduces overall system complexity by sharing structural components and control systems between the main transfer motion and the tapping motion.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The transfer plunger's own motion is utilized to generate the tapping effect through controlled deceleration and reversal. The inertial forces generated during rapid deceleration and direction change of the transfer plunger itself create the necessary tapping action, eliminating the need for a completely separate tapping mechanism.

Inventive Principle:
Principle #25Self-service

3Productivity

If the powder compacts are sheared off by the transfer stamps on the upper edge of the base segment, then the powder falls into the capsule base, but metering inaccuracies and product carryover occur

Engineering Contradiction:
Improvepowder transfer speedVSAvoidmetering accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The mechanical shearing action is replaced with a controlled detachment mechanism using vibrations and opposite-direction acceleration. This allows the powder compacts to detach cleanly from the transfer plunger through forceful separation rather than uneven shearing, maintaining metering accuracy while ensuring complete transfer into the capsule base.

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

Solution Approach 2:

The forces acting on the powder compacts are changed from static shearing forces to dynamic separation forces through controlled acceleration in the opposite direction. This parameter change in the force application method enables complete and accurate powder detachment without the metering inaccuracies caused by uneven shearing.

Inventive Principle:
Principle #35Parameter changes

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 solution ensures reliable tapping off of powder compacts during transfer, preventing sticking and ensuring accurate metering by generating a tear-off force greater than the adhesive forces, thus minimizing contamination and product carryover.

Implementation Method 1

the spontaneous acceleration of the heavy transfer stamps on the one hand and the inertia of the very light powder compacts (filling material) on the other hand, a tear-off force is caused that is greater than the adhesive forces

Methodology Applied
Scientific EffectInertia: Inertia

Implementation Method 2

The pneumatic cylinder 36 accelerates the lifting ram 38 upwards in the opposite direction to the transfer direction and hits the underside of the yoke 34 with full force

Methodology Applied
Scientific EffectImpact force: Impact Force

Data Source

PatentEP2175825B1Device for metering of powdery filling material
Publication Date: 2015.11.04 ROBERT BOSCH GMBH
  • EP2175825B1 patent drawingFigure 1
  • EP2175825B1 patent drawingFigure 2
  • EP2175825B1 patent drawingFigure 3

AI summary

A device for metering of powdery filling material is proposed, with a filling material container (12), on the bottom of which at least one metering aperture (14) is arranged, with at least one transfer ram (16) which can be introduced by a movement system (24, 25) into the metering aperture (14) in order to transfer the filling material located in the metering aperture (14) into a receptacle (22), characterized in that, in addition to the movement system (24, 25), a drive unit (27) is provided for applying a force to the transfer ram in order to assist the transfer of the filling material into the receptacle (22).