Famous Patents
3M employee and church chorister Art Fry needed something to temporarily mark pages in his hymnal. He was in luck because his colleague, Spencer Silver, accidentally developed a glue that was too weak for other purposes. After initially discouraging consumer response, Post-it Notes became a hit in 1979.
PatentStorm News
Make the Most of Our Site
See this month's Top Inventors and Most Cited Patents.
Stay on top of the latest innovations by subscribing to an RSS feed.
Registered users: Manage your profile.
| Number | Title | Issue Date |
| 7355369 | On-load transformer tap changing system An on-load transformer tap changing system, for example for a power transformer, wherein the secondary or primary of a transformer includes at least one first tap and one second tap. A main connection circuit is used for permanent connection of the first tap or the ... | 04/08/2008 |
| 7123578 | Communication system for driving pairs of twisted pair links A communications system includes tow high speed communication links formed by pairs of transformers at either end thereof. A phantom circuit formed by the pairs of transformers is used to distribute power to devices connected to the high speed links. In transmission... | 10/17/2006 |
| 6810069 | Electrical arc furnace protection system Protection systems are described for electrical systems such as electrical arc furnaces. The protection systems may be designed and used to detect and clear faults that may occur within the electric arc furnace. For example, a pair of Rogowski coils may be used to d... | 10/26/2004 |
| 6794618 | Method for electrical heating of furnaces for heat treatment of metallic workpieces In order to refine a method for electric heating of furnaces for heat treating metallic workpieces, especially vacuum furnaces usable for plasma carburizing or nitriding, in which the heater elements of a furnace are supplied with a heating voltage that is generated... | 09/21/2004 |
| 5475202 | Method and apparatus for heating a thermionic detector source The bead source for the thermionic detector of a gas chromatograph is heated by the secondary winding of a transformer having a center-tapped primary and operating in the push-pull configuration. The voltage drop across the bead is compared with a presele... | 12/12/1995 |
| 5453598 | Apparatus for the transfer of electrical power to a balancer A method and apparatus is disclosed for transferring electrical power to a balancer 14 without the need for a physical connection between the balancer and the power source 16 or the controller 12 and which also provides for data communication between a ba... | 09/26/1995 |
| 5175412 | Electrical control system for an electrically heated window in motor vehicle An electrical control system for an electrically heated window in a motor vehicle has a voltage source including a generator, a voltage regulator for regulating a generator output voltage, a transformer switched between the generator and a heating window,... | 12/29/1992 |
| 4668851 | Circuitry for control of the temperature of a heating element adapted to be contacted by a material to be heated A circuit arrangement for control of the temperature of a heating element adapted for contact by a material to be heated includes a transformer wherein the secondary winding is a metal ring which is the heating element with a temperature detection winding... | 05/26/1987 |
| 4571487 | Methods and apparatus for supplying electrical power for proximity effect heat-tracing A proximity effect heat-tracing system in which proximity effect heat-tracing circuits are fed in either direction from a plurality of feed points connected to a single main transformer to increase the length of pipeline supplied by a single main transfor... | 02/18/1986 |
| 4564747 | Methods and apparatus for detecting abnormalities in proximity effect heat-tracing circuits Methods and apparatus for detecting abnormalities in proximity effect pipeline tracing circuits by coupling conductive elements carrying proximity effect circuit currents and having opposite polarities. These conductive elements are coupled to an addition... | 01/14/1986 |
| 4562338 | Heating power supply apparatus for polycrystalline semiconductor rods A heating power supply apparatus for polycrystalline semiconductor rods, including a power transformer and anti-parallel thyristor unit groups connected to respective portions of the secondary of the power transformer, balance transformer groups connected... | 12/31/1985 |
| 4506131 | Multiple zone induction coil power control apparatus and method A plurality of zones of an induction heating coil are individually controlled by varying the current through one or more zones of the coil to obtain a desired temperature profile in a workpiece. The current flow through a zone of the coil is determined by... | 03/19/1985 |
| 4405894 | Voltage control and balancing circuit A circuit is described for controlling voltage input to a pair of resistances. A main transformer and variable auto transformer are wired in cascade between the voltage supply and the resistances. The resistances are wired in series to the output of the v... | 09/20/1983 |
| 4237369 | Wild stress relief power supply apparatus Temperature responsive power supply apparatus for electrical resistance heating, e.g. for weld stress relief, has a power supply transformer comprising first and second secondary windings in series with one another and first, second and third conductors f... | 12/02/1980 |
| 4074335 | Detecting circuit A detecting circuit comprises a magnetic core having a rectangular magnetic characteristic, a first winding coupled magnetically to the magnetic core, for applying a current to be detected, and a second winding coupled magnetically to the magnetic core, f... | 02/14/1978 |
