Permanent Magnet Chuck Detection for Double-Sheet Attraction
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Solution Overview
Problem
Existing workpiece attraction devices, such as electromagnetic chucks and magnetic grippers, are prone to attracting multiple workpieces unintentionally due to surface moisture or oil, leading to defects and potential damage to forming dies, and existing detection methods are susceptible to external magnetic fields and require complex separation mechanisms.
Innovation Solution
An excessive attraction detection device using a cylinder member with a displaceable permanent magnet and a sensor to detect the number of workpieces by adjusting the biasing forces between the magnet and workpieces, ensuring the magnet is not influenced by external fields and can be easily separated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a detection coil is used to detect workpiece attraction, then detection capability is provided, but the device is easily influenced by external magnetic fields and may malfunction
Solution Approach 1:
The patent replaces the electromagnetic detection coil system with a mechanical detection system. A permanent magnet is positioned close to the workpiece surface, and a detector measures the magnetic force or position of the magnet. This mechanical approach eliminates susceptibility to external magnetic fields that affect electromagnetic coils, while maintaining detection capability through direct mechanical or magnetic field measurement at the workpiece interface.
2Adaptability or versatility
If a detection device is integrated with the workpiece attraction device, then detection function is added, but separation from the workpiece becomes complex
Solution Approach 1:
The patent merges the detection function directly into the workpiece attraction device structure. The permanent magnet used for attraction also serves as the detection element, and the detector is integrated into the attraction device housing. This eliminates the need for separate detection devices and complex separation mechanisms, as the entire assembly can be simply attached to or removed from the workpiece as a single unit.
3Force
If magnetic force is increased to attract workpieces, then attraction capability is improved, but multiple workpieces may be unintentionally attracted
Solution Approach 1:
The patent concentrates the magnetic attraction force at a specific location by positioning the permanent magnet close to the workpiece surface, creating a localized high magnetic field zone. The detector monitors the magnetic force or position to ensure only one workpiece is attracted. This localized approach maintains strong attraction capability while preventing excessive attraction of multiple workpieces through spatial concentration of the magnetic field.
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
Effectively detects excessive workpiece attraction without interference from external magnetic fields and simplifies separation, preventing defects and die damage by accurately determining the number of workpieces retained.
Implementation Method 1
a magnetic part including a permanent magnet used for attraction
Implementation Method 2
a sensor is provided to detect a position of the permanent magnet used for attraction
Data Source
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AI summary
An excessive attraction detection device (10) is composed of a cylinder unit (12) including pistons (36, 38), and a magnet unit (50) including a permanent magnet (58) for attraction. The permanent magnet for attraction can be displaced integrally with the pistons between an attraction position and a retreat position. The attraction position separation energizing force acting on the pistons is larger than the magnetic force of mutual attraction between the permanent magnet for attraction and the workpiece when one workpiece is attracted and held by a workpiece attraction device and smaller than the magnetic force of mutual attraction between the permanent magnet for attraction and the workpiece when two workpieces are attracted and held by the workpiece attraction device.