Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Polarity-responsive
Reexamination Certificate
1999-10-13
2001-11-20
Donovan, Lincoln (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Polarity-responsive
C335S185000, C335S132000
Reexamination Certificate
active
06320485
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electromagnetic relay assembly with a linear motor capable of handling current transfers of up to and greater than 100 amps.
DESCRIPTION OF THE PRIOR ART
There are a few designs for electromagnetic relay assemblies currently in the prior art. These electromagnetic relay assemblies typically include a relay motor assembly that is magnetically coupled to an actuation assembly. The actuation assembly is then operatively coupled to a contact spring that is positioned opposite a pair of conductively isolated contact points. The relay motor typically drives the actuation assembly which in turn drives the contact spring into contact with a pair of contact points positioned directly across from it.
The contact springs typically serve a dual purpose. They ensure good contact with the contact points, and they form a conductive pathway between the contact points. Contact springs are typically made of copper or a copper alloy, the copper alloys typically have lower conductivity than plain copper. Plain copper can typically sustain less than 20 amps per square millimeter without causing excess heat build up in the copper. Excess heat build up in the contact springs will cause the contact springs to lose there spring property. This results in a loss of contact pressure which leads to increased contact resistance which in turn causes the relay to fail. Consequently, most electromagnetic relays can only sustain currents of less than 20 amps per square millimeter through their copper contact springs.
In order to increase current density while minimizing the heat generated by higher currents only two options are currently available. One is to make the contact springs wider, requiring an increase in the size of the relay and increasing the bending force needed by the actuator assembly and the relay motor. The other option is to increase the thickness of the spring which will also increase the bending force needed by the actuator assembly and the relay motor. Consequently, typical electromagnetic relays are not-particularly suited for applications which require higher current flows of up to 100 amps.
Also, current relay motors typically have relay motors which generate a rotational movement. Contact springs typically require only a linear movement in the actuator assembly to bring it into contact with the contact points. Consequently additional pieces are required in the actuation assembly in order to convert the rotational movement generated by the relay motor into a linear movement required by most contact springs, adding to the expense of producing and assembling the electromagnetic relay.
Accordingly, there is a need for an electromagnetic relay which is capable of handling currents of up to 100 amps.
Accordingly there is also a need for an electromagnetic relay with a motor that generates a linear movement to accommodate contact assemblies which require only a linear movement.
The present invention is an electromagnetic relay assembly with a linear motor capable of transferring currents of up to 100 amps for use in regulating the transfer of electricity or in other applications requiring the switching of currents of up to 100 amps.
As will be described in greater detail hereinafter, the present invention solves the aforementioned and employs a number of novel features that render it highly advantageous over the prior art.
SUMMARY OF THE INVENTION
Accordingly it is an object of this invention to provide an electromagnetic relay that is capable of safely transferring currents of greater than 100 amps.
A further object of the present invention is to provide an electromagnetic relay with a relay motor that generates a linear movement.
To achieve these objectives, and in accordance with the purposes of the present invention the following electromagnetic relay is presented.
A relay motor assembly has an elongated coil bobbin with an axially extending cavity therein. An excitation coil made of a conductive material, preferably copper is wound around the bobbin. Coil terminals are conductively attached to the excitation coil and mounted on the bobbin providing a means for sending a current through the excitation coil.
A ferromagnetic frame is partially disposed within the axially extending cavity within the bobbin. The ferromagnetic frame has a first contact section with a first tongue portion extending generally perpendicularly from a first contact section and above the bobbin, and a second contact section having a second and third tongue portions extending generally perpendicularly from the second contact section and above the bobbin, the second tongue portion lying below the third tongue portion.
An actuator assembly has a first and second pole piece made of sheets of ferromagnetic material and a permanent magnet sandwiched in between the pole pieces. An actuator frame made of a nonconductive material is operatively coupled to the first and second ferromagnetic pole pieces, and the permanent magnet. The actuator assembly is positioned so that a portion of the first and second pole pieces are located in between the second and third tongue portion on the second contact section and that the first tongue portion of the first contact section is positioned in between the first and second pole pieces. The first and second pole pieces are magnetically coupled to a tongue portion on opposing contact sections.
A lever assembly is comprised of a housing, a plurality of levers, and a plurality of contact arms. The levers are preferably L-shaped levers. The L-shaped levers are rotatably mounted onto a lever attachment point. The L-shaped lever has a first portion and a second portion. The first portion operatively engaged to the actuator frame and the second portion operatively engaged to the side actuator.
A contact bridge assembly is comprised of a plurality of contact springs, preferably 2, a pair of contact buttons, and a contact bridge made of a sheet of conductive material, preferably copper. The contact bridge is operatively coupled to the contact arm. The contact bridge serves as a conductive pathway between a pair of contact points generally positioned across from the contact bridge.
The conductive bridge is connected to the contact spring. The contact spring provides a force on the contact bridge sufficient to ensure good contact between the contact bridge and the contact points lying across from the contact bridge. A pair of contact buttons are also conductively connected to the contact bridge the contact buttons further ensuring that good contact is made between the contact bridge and the two contact points lying across from the contact bridge.
A relay housing encloses the components of the present invention. The relay housing is preferably made of a nonconductive material and has contact terminal assemblies attached thereto and extending through a wall of the relay housing. The contact terminal assemblies typically have isolated contact points positioned across from the contact bridge.
The present invention is driven by the movement of the pole pieces in response to the polarity of a current running through the excitation coil. A linear movement occurs when the polarity of the current running through the excitation coil causes the magnetic flux to induce the first and second pole pieces to magnetically couple to the contact sections opposite the contact section that they were previously magnetically coupled to. This linear movement of the pole pieces drive the movement of the actuator assembly.
The two directional movement of the actuator assembly is then translated by the L-shaped lever onto the side actuator in only one direction. Consequently, the movement of the actuator assembly will either cause the L-shaped lever either to apply a force on the side actuator or else the movement of the actuator assembly will cause the L-shaped lever to apply no force to the side actuator. When the L-shaped lever applies a force onto the side actuator, the side actuator is pulled from its previous position causing the contact bridge to break contact
Donovan Lincoln
Meroni & Meroni P.C.
Meroni, Jr. Charles F.
Nguyen Tuyen
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