PTC device with extended thickness
AssigneeTherm-O-Disc, Incorporated
InventorsJohn J. Krimm, Jeffrey A. West, Robert L. Newman
Life of this patent
Estimating the term…
Abstract
A thin PTC device that includes a layer of PTC material sandwiched between a pair of metal plates is provided with an increased effective thickness by outwardly extending flanges on at least one of the metal plates. This allows a close fit of the PTC device in a pocket that otherwise would be too large for holding the PTC device properly.
Claims35
A thermal protector comprising a substantially flat layer of material that has a positive temperature coefficient of resistance and normally provides very little resistance to current flow while automatically switching to a very high resistance state at a predetermined elevated temperature to substantially block flow of all but a trickle current therethrough, said material having outer opposite faces, metal foil electrodes laminated to said opposite faces, a pair of opposite metal terminal plates soldered to said electrodes with said material sandwiched therebetween, said plates having top and bottom ends and opposite sides, a terminal leg extending from said bottom end of each of said plates for connecting said PTC device in an electric circuit, said plates having outer surfaces spaced-apart a thickness distance measured in a thickness direction substantially perpendicular to and between said outer surfaces, and means permanently attached to at least one of said plates and extending outwardly therefrom as a unitary part of said thermal protector for providing said thermal protector with an effective thickness measured in said thickness direction that is at least about two times said thickness distance for providing close reception of said thermal protector in a pocket having a pocket thickness that is about the same as said effective thickness of said thermal protector.
A PTC device comprising a layer of PTC material sandwiched between and bonded to a pair of opposite terminal plates having top and bottom ends and opposite sides, each of said plates and said PTC material having substantially coextensive areas, a terminal leg extending outwardly from said bottom end of each of said plates, said top and bottom ends and said opposite sides defining a plate periphery, and a plurality of flanges integral with at least one of said plates and extending outwardly therefrom substantially perpendicular thereto along said plate periphery, said flanges being spaced from and independent of said terminals.
A motor brush holder having a pocket for receiving a thermal protector for connection in circuit with an electric motor, said pocket having top and bottom pocket openings, a predetermined pocket thickness and a predetermined pocket width, a pocket abutment adjacent said pocket bottom opening, a PTC device received in said pocket and having a bottom end engaging said abutment, said PTC device comprising a substantially flat layer of PTC material sandwiched between a pair of substantially flat opposite terminal plates, said terminal plates having plate outer surfaces and said PTC device having a predetermined thickness between said plate outer surfaces that is substantially less than said pocket thickness, means permanently attached to at least one of said plates and extending outwardly therefrom for providing said PTC device with an effective thickness measured in the same direction as said predetermined thickness that is substantially greater than said predetermined thickness for close reception of said PTC device in said pocket, and terminal legs on said terminal plates extending through said pocket bottom opening for connection in circuit with an electric motor.
A motor brush holder having a pocket for receiving a thermal protector for connection in circuit with an electric motor, said pocket having top and bottom pocket openings, a predetermined pocket thickness and a predetermined pocket width, a pocket abutment adjacent said pocket bottom opening, a PTC device received in said pocket and having a bottom end engaging said abutment, said PTC device comprising a substantially flat layer of PTC material sandwiched between a pair of substantially flat opposite terminal plates, said terminal plates having plate outer surfaces and said PTC device having a predetermined thickness between said plate outer surfaces that is substantially less than said pocket thickness, said terminal plates having terminal legs extending through said pocket bottom opening for connection in an electric motor circuit, and at least one of said plates having at least one integral flange extending outwardly substantially perpendicular thereto for providing said PTC device with an effective thickness along said flange measured in the same direction as said predetermined thickness that is substantially greater than said predetermined thickness for close reception of said PTC device in said pocket.
A thermal protector comprising a substantially flat layer of material that has a positive temperature coefficient of resistance and normally provides very little resistance to current flow while automatically switching to a very high resistance state at a predetermined elevated temperature to substantially block flow of all but a trickle current therethrough, said material being sandwiched between and bonded to a pair of opposite metal terminal plates having top and bottom ends and opposite sides, said thermal protector having top and bottom ends and opposite sides that substantially coincide with said top and bottom ends and said opposite sides of said plates, a terminal leg extending from said bottom end of each of said plates at said bottom end of said thermal protector for connecting said thermal protector in an electric circuit, and a bottom flange extending outwardly from said bottom end of at least one of said plates integrally therewith, a direction from each said plate toward said material being an inward direction and a direction from each said plate away from said material being an outward direction, and said bottom flange extending in said outward direction.
A thermal protector comprising a substantially flat layer of material that has a positive temperature coefficient of resistance and normally provides very little resistance to current flow while automatically switching to a very high resistance state at a predetermined elevated temperature to substantially block flow of all but a trickle current therethrough, said material being sandwiched between and bonded to a pair of opposite metal terminal plates having top and bottom ends and opposite sides, said thermal protector having top and bottom ends and opposite sides that substantially coincide with said top and bottom ends and said opposite sides of said plates, a terminal leg extending from said bottom end of each of said plates at said bottom end of said thermal protector for connecting said thermal protector in an electric circuit, and a side flange extending outwardly from each of said opposite sides of at least one of said plates integrally therewith, a direction from each said plate toward said material being an inward direction and a direction from each said plate away from said material being an outward direction, and each said side flange extending in said outward direction.
A thermal protector comprising a substantially flat layer of material that has a positive temperature coefficient of resistance and normally provides very little resistance to current flow while automatically switching to a very high resistance state at a predetermined elevated temperature to substantially block flow of all but a trickle current therethrough, said material being sandwiched between and bonded to a pair of opposite metal terminal plates, said plates having outer surfaces spaced-apart a thickness distance measured in a thickness direction substantially perpendicular to and between said outer surfaces, a thickness extension permanently attached to at least one of said plates and extending outwardly therefrom as a unitary part of said thermal protector for providing said thermal protector with an effective thickness measured in said thickness direction that is at least about two times said thickness distance for providing close reception of said thermal protector in a pocket, a direction from each said plate toward said material being an inward direction and a direction from each said plate away from said material being an outward direction, said thickness extension extending in said outward direction, a terminal leg extending from each said plate for connecting said thermal protector in an electrical circuit, said thickness extension being separate and independent from each said terminal leg, said material having an outer periphery, and at least a substantial portion of said thickness extension being located on or within said outer periphery.
Dependencies are inferred from the claim text.