Drum Cam Transport Mechanism for Precise Low-Energy Workpiece Motion

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Solution Overview

Problem

Existing transport devices for workpieces face challenges in achieving precise and energy-efficient rotational and linear movement between rest positions while maintaining dynamics, often requiring significant design changes that increase production and maintenance costs.

Innovation Solution

A transport device with a mechanical control cam and motor control curve that have variable slopes, allowing for the superimposition of movement components to achieve a desired movement profile, optimizing energy use and reducing jerk values by operating the motor close to its optimal operating point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the motor is operated to achieve precise movement profiles with conventional fixed control, then movement precision is maintained, but energy consumption increases and the motor cannot operate at optimal points

Engineering Contradiction:
Improveenergy consumptionVSAvoidmovement precision
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the control system adaptable and flexible. The motor control curve is made variable rather than fixed, allowing the system to adjust the motor's operation dynamically. This enables the motor to operate closer to its optimal operating point while still achieving the desired movement profile, thus reducing energy consumption without sacrificing precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameters of the control system by introducing a variable motor control curve with adjustable slope. By modifying the control parameters (the relationship between motor position and control signal) dynamically, the system can optimize energy consumption while maintaining the required movement precision through coordinated adjustment of both mechanical cam geometry and control curve characteristics.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If design changes are made to reduce friction and improve energy efficiency, then energy consumption decreases, but production and maintenance costs increase

Engineering Contradiction:
Improveenergy consumptionVSAvoidproduction cost
Core Design Contradiction:
Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent partially replaces the purely mechanical control system with a hybrid approach that combines mechanical elements (cam with variable slope groove) and electronic control (variable motor control curve). This substitution allows energy efficiency improvements through control optimization rather than extensive mechanical redesign, thereby reducing production and maintenance costs while still achieving lower energy consumption.

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

3Manufacturing precision

If a more powerful motor is used to maintain precision and dynamics, then movement precision is improved, but energy consumption increases

Engineering Contradiction:
Improvemovement precisionVSAvoidmotor power
Core Design Contradiction:
Manufacturing precisionVSPower

Solution Approach 1:

By changing the control parameters through variable slope cam and variable motor control curve, the system can achieve the same movement precision with a less powerful motor. The optimized control allows the motor to operate more efficiently, delivering the required precision without needing excess power capacity, thus reducing both motor size and energy consumption.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If the mechanical control cam has a fixed slope for simple manufacturing, then production cost is reduced, but energy efficiency and movement profile optimization are compromised

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidenergy efficiency
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent introduces variable slope parameters in the mechanical cam while coordinating them with variable parameters in the electronic control curve. This parameter variation enables energy efficiency optimization without requiring complex manufacturing processes. The variable slope cam can be manufactured using standard techniques, and the combined mechanical-electronic control approach achieves superior energy efficiency compared to fixed slope designs.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3602217B1Transport device for rotatably and/or linearly moving a workpiece
Publication Date: 2021.03.24 WEISS GMBH
  • EP3602217B1 patent drawingFigure 1a~1c
  • EP3602217B1 patent drawingFigure 2a~2c

AI summary

The invention relates to a transport device comprising a transport element for receiving a workpiece, said transport element being movable by means of a motor from a first idle position into a second idle position, the transport element being drivably connected to at least one driver that engages in a drive groove of a drum cam that can be driven by the motor, which can be controlled by means of a programmable control device on the basis of a motor control curve. The drive groove has a variable incline at least in sections and the motor control curve also has a variable course at least in sections, the movement of the transport element being generated by a simultaneous superposition of a first movement component based on a region of variable incline of the drive nut and a second movement component based on a variable region of the motor control curve.