Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Multiple contact type
Reexamination Certificate
2000-03-10
2001-10-02
Donovan, Lincoln (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Electromagnetically actuated switches
Multiple contact type
Reexamination Certificate
active
06297717
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to electromagnetic contactors, and more particularly to a contactor having a floating armature therein.
An electrical contactor is a switch that is adapted to open and close repeatedly to supply and interrupt electrical power to electrical loads, such as motors and the like. An electromagnetic contactor is a contactor that is caused to operate by an electromagnet. The movable contacts are moved from an open position to a closed position by an armature attached to a movable contact carrier assembly depending on the magnetism produced by a coil. The armature is typically mounted to the carrier with fasteners, such as rivets. Other contactors use spring clips either bearing against the surface of the armature or through an aperture in the armature to retain the armature tightly against the carrier.
It has been determined that such configurations can limit the life of a contactor. For example, if the fasteners, such as rivets, break or become loose, the armature can bind, or worse, the contactor can become completely inoperable. Further, a coil can apply an inconsistent magnetic force and/or the physical clearance between the carrier and the housing can cause “window locking.” This results from the carrier tilting within the housing, thereby causing the carrier to bind within the housing during its travel from one position to the next.
While such prior art retention means between the armature and the carrier have functioned adequately, there is an ongoing manufacturing need to simplify assembly, reduce cost, and improve operation of the contactor.
It would therefore be advantageous to have a molded one piece carrier assembly that can retain an armature loosely therein and thereby extend the overall life of the contactor.
SUMMARY OF THE INVENTION
The present invention provides an electromagnetic contactor in which the armature is loosely attached/connected to the contact carrier, and is slideably guided within the contactor to retain the armature within the connecting structure of the carrier that provides extended life and easy assembly.
In accordance with one aspect of the invention, an electrical contactor includes a housing having a set of stationary contacts mounted therein and a set of movable contacts located on a contact carrier within the housing. The movable contacts being in operable association with the stationary contacts, such that when the contacts close, electric power is supplied to a load. The contact carrier has an armature slot integrally molded therewith. An armature is loosely situated in the armature slot of the contact carrier so as to float therein. In this manner, the armature is easily inserted into the carrier while the carrier assembly is mounted in the housing. Moreover, the carrier is less likely to experience window locking that is typically caused by the armature being tightly bound to the carrier.
According to another aspect of the invention, a contactor is disclosed having a floating armature within a contactor housing. The housing has an armature stop and an armature channel to maintain the floating armature in a desired position and aligned with a return spring. A contact carrier is provided having an armature slot integrally molded therewith and having side channels to loosely retain the floating armature therein. The housing has two elongated sides that are parallel to a length of the armature. Each elongated side has a carrier ear slot therein to accept one of the pair of offset ears of the carrier. The housing walls guide the ends of the armature while moving vertically within the housing to maintain the armature position within the carrier.
The present invention provides numerous manufacturing advantages. For example, by providing an armature slot integrally molded with the carrier, no additional fastening means are necessary for attaching the armature to the carrier. By not fixing the armature securely to the carrier, during operation of the contactor, the armature does not exert excessive torsional force on the carrier thereby preventing window locking. During life tests, it was found that the floating armature arrangement of the present invention significantly reduced the load on the carrier during operation and resulted in a significant increase in life of the contactor.
REFERENCES:
patent: 3458838 (1969-07-01), Isler
patent: 3710288 (1973-01-01), Grunert
patent: 3748608 (1973-07-01), Grunert et al.
patent: 3840830 (1974-10-01), Hardman
patent: 4525694 (1985-06-01), Dennison et al.
patent: 5717370 (1998-02-01), Haas
Donovan Lincoln
Eaton Corporation
Ziolkowski Timothy J.
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