Pencil shaped magnetic coating thickness gauge
First Claim
1. Magnetic coating-thickness gauge for measuring the thickness of a non-magnetic coating on a ferromagnetic substrate of the type wherein a permanent magnet is suspended by spring means for axial movement within a tubular housing resembling a pencil, said housing being provided with an axially extending slot, the magnet having a pole surface for contact with a coating to be measured on said substrate through an opening at one end of the housing, manually operable slide means encircling the exterior of the housing for slidable movement along the length of the housing in a generally straight line, connecting means extending through said slot between the slide means and spring means to permit the slide means to exert increasing force on said magnet when the slide means is moved away from said one end of the housing to dislodge the magnet from said coating and scale means on said housing with said slide means to denote coating thickness as a function of the force exerted on said magnet, said slide means including friction means engageable with a surface of the housing to hold the slide means in position when released by an operator of the gauge.
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Accused Products
Abstract
A coating thickness gauge employs a permanent magnet suspended on a coil spring within a pencil shaped housing; the spring being attached to a slide which encircles the housing aid is manually slidable along the length of the housing to adjust the tension of the spring exerted on the magnet. The end of the magnet projects through the end of the housing in contact with a coating deposited on a ferromagnetic base so that the thickness of the coating is measured in terms of the spring tension exerted when the side is moved to pull the magnet away from the coating and this thickness can be read on a scale mounted along the length of the housing. The slide can be provided with internal resilient friction rings or an internal expandable friction element can be placed in the housing to resist inadvertent movement of the slide and an internal stop can be employed to prevent bouncing of the magnet to displace the slide. Several types of indicator or pointer devices can be employed on the slide to facilitate reading the scale.
21 Citations
17 Claims
- 1. Magnetic coating-thickness gauge for measuring the thickness of a non-magnetic coating on a ferromagnetic substrate of the type wherein a permanent magnet is suspended by spring means for axial movement within a tubular housing resembling a pencil, said housing being provided with an axially extending slot, the magnet having a pole surface for contact with a coating to be measured on said substrate through an opening at one end of the housing, manually operable slide means encircling the exterior of the housing for slidable movement along the length of the housing in a generally straight line, connecting means extending through said slot between the slide means and spring means to permit the slide means to exert increasing force on said magnet when the slide means is moved away from said one end of the housing to dislodge the magnet from said coating and scale means on said housing with said slide means to denote coating thickness as a function of the force exerted on said magnet, said slide means including friction means engageable with a surface of the housing to hold the slide means in position when released by an operator of the gauge.
Specification