Sensing system for magnetic clamping devices
First Claim
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1. A magnetic clamping system for a mold of an injection molding machine, comprising:
- a magnet device having a clamping surface for engaging said mold at a clamping interface;
a plurality of switchable permanent electromagnets on said magnet device for establishing a magnetic clamping force at said clamping interface, said electromagnets including a coil member;
a movement detector sensor system operatively associated with at least one of said electromagnets and including first means for determining changes in magnetic flux conditions at said clamping interface and generating a first caution signal if a threshold value is exceeded;
a permeability sensor system operatively associated with at least one of said electromagnets and including second means for determining changes in flux at said between a demagnetized condition and a magnetized condition and generating a second caution signal if said threshold value is not attained; and
controller means for receiving said caution signals and determining continued activity of said injection molding machine based thereon.
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Abstract
A sensor system for determining acceptable magnetization between a magnetic clamp and a mold patent for a quick mold change system on an injection molding machine includes secondary sensing coils magnetically coupled with a switchable magnet in the clamp effecting a voltage output in accordance with magnetic flux conditions between the magnets and the mold and providing a control signal based on changes in said flux condition for controlling activity of said workpiece in accordance therewith.
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Citations
31 Claims
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1. A magnetic clamping system for a mold of an injection molding machine, comprising:
- a magnet device having a clamping surface for engaging said mold at a clamping interface;
a plurality of switchable permanent electromagnets on said magnet device for establishing a magnetic clamping force at said clamping interface, said electromagnets including a coil member;
a movement detector sensor system operatively associated with at least one of said electromagnets and including first means for determining changes in magnetic flux conditions at said clamping interface and generating a first caution signal if a threshold value is exceeded;
a permeability sensor system operatively associated with at least one of said electromagnets and including second means for determining changes in flux at said between a demagnetized condition and a magnetized condition and generating a second caution signal if said threshold value is not attained; and
controller means for receiving said caution signals and determining continued activity of said injection molding machine based thereon.
- a magnet device having a clamping surface for engaging said mold at a clamping interface;
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2. A method for maintaining adequate magnetic forces at an interface between a magnetic clamping device and a workpiece during operations thereat, comprising the steps of:
- placing an inductive coil in said clamping device adjacent said interface;
detecting the change in flux in said coil during said operations;
generating a first alert condition if said change in flux exceeds a threshold value;
detecting the level of flux in said coil prior to said operations; and
generating a second alert condition if said level of flux does not attain a threshold level.
- placing an inductive coil in said clamping device adjacent said interface;
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3. A sensor system for determining acceptable magnetization between a magnet device having a switchable magnet generating a magnetic clamping force at a workpiece, comprising:
- coil means magnetically coupled with said switchable magnet for effecting a voltage output in accordance with magnetic flux conditions between the magnet and the workpiece related to changes in said magnetic clamping force; and
control means coupled to said output for providing a control signal based on changes in said flux conditions; and
means for initiating a first magnetization of said magnet device, ceasing said first magnetization, and initiating a second magnetization of said magnet device after said ceasing, said control signal being effective only during said second magnetization. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
- coil means magnetically coupled with said switchable magnet for effecting a voltage output in accordance with magnetic flux conditions between the magnet and the workpiece related to changes in said magnetic clamping force; and
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20. A sensor system for determining acceptable magnetization between a magnet device having a switchable magnet generating a magnetic clamping force at a workpiece, comprising:
- coil means magnetically coupled with said switchable magnet for effecting a voltage output in accordance with magnetic flux conditions between the magnet and the workpiece related to changes in said magnetic clamping force; and
control means coupled to said output for providing a control signal based on changes in said flux conditions wherein said control means generates said control signal is changes in said flux conditions exceed a threshold value, includes means for varying said threshold value and determines flux conditions at said secondary coil and generates said control signal if a threshold value is not attained, said control means further determining the level of flux change between a demagnetized condition for the switchable magnet and a magnetized condition for the switchable magnet and generates said control signal if said threshold value is not attained; and
resetting integrator means for said control means for receiving said output and generating an output based on said flux change, and comparator means receiving said output and generating said control signal if said threshold value is not attained. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
- coil means magnetically coupled with said switchable magnet for effecting a voltage output in accordance with magnetic flux conditions between the magnet and the workpiece related to changes in said magnetic clamping force; and
Specification