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US 7,564,330 B2Granted
Reed switch contact coating
AssigneeKey Safety Systems, Inc.
InventorsMark Pickhard, John Wineke, David Lea, Andrew Petraszak, Steve Topel, Tom Lenz
Life of this patent
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Abstract
A reed switch has a contact surface composed of three layers of metal applied to the contacts of the reed switch. The three layers comprise first a layer of titanium of approximately 15 to 150 micro inches, second a layer of molybdenum of 15 to 150 micro inches, and finally a contact layer of 5 to 20 micro inches of ruthenium, or other platinum group metal or alloy. The layers may be applied by any suitable methods, for example by sputtering.
Claims18
A reed switch comprising:
- a glass capsule defining a hermetically sealed volume;
- at least a first ferromagnetic lead extending into the hermetically sealed volume;
- at least a second ferromagnetic lead extending into the hermetically sealed volume;
- the first ferromagnetic lead having a flexible blade portion and a contact portion extending from the flexible blade portion;
- and
- wherein the contact surface is coated with a layer of a metal which wears flat when used as a contact in the reed switch, overlain by a layer of a refractory metal, which in turn is overlain by a layer of a platinum group metal or platinum group metal alloy.
3 more elements
A reed switch comprising:
- a glass capsule, defining an interior hermetically sealed volume;
- a first reed switch blade having a first lead extending into the glass capsule hermetically sealed volume, wherein the first reed switch blade has a first contact surface positioned within the hermetically sealed volume;
- at least a second lead extending into the glass capsule and positioning a second contact surface within the hermetically sealed volume;
- wherein at least the first reed switch blade is flexibly movable to engage the second contact surface with the first contact surface;
- and
- wherein at least the first contact surface has formed thereon a layer of titanium, the titanium layer being overlain by a layer of molybdenum which is formed on the titanium layer, the molybdenum layer being overlain by a layer of a platinum group metal or platinum group metal alloy which is formed on the molybdenum layer, the layer of a platinum group metal or platinum group metal alloy being outermost so as to engage the second contact surface.
3 more elements
A method of reducing the cost of a reed switch comprising:
- taking an existing reed switch design having a contact coating of a selected thickness, and replacing the contact coating of the selected thickness with a three layer coating having a total thickness which is within plus or minus 10% of the selected thickness, the three layer coating comprised of a layer of titanium, overlain by a layer of molybdenum, which in turn is overland by a layer of a platinum group metal or platinum group metal alloy.
Dependencies are inferred from the claim text.