Electrical connectors – Metallic connector or contact having movable or resilient... – Screw-thread operated securing part
Reexamination Certificate
2002-06-06
2004-04-13
Ta, Tho D. (Department: 2833)
Electrical connectors
Metallic connector or contact having movable or resilient...
Screw-thread operated securing part
C174S08400S, C361S310000, C403S362000
Reexamination Certificate
active
06719593
ABSTRACT:
This invention concerns a screw terminal connected to a conductor device on electrical equipment for connecting at least one electrical conductor to this device.
In particular, it concerns a screw terminal composed of a connection cage equipped with a tapped hole, a screw with a threaded head and stem that screw into the tapped hole, and an elastic pressure device for application against the electrical conductor. The cage and/or the screw are moveable inside the housing on the electrical equipment, and the pressure device is composed of a head plate and a pressure plate connected to each other by an elastic wing that is designed to store torque energy, the head plate being subject to pressure from the screw head, and the pressure plate being applicable against the conductor or the equipment's conductor part.
The document DE U 1 935 560 describes a terminal of this type. A U-shaped stirrup pressure device, composed of a high wing and a low wing connected by a core is engaged by the high wing under the screw head and is applicable through the low wing against a conductor introduced into the cage; the stirrup core is a little higher than the length of the threaded portion in order to create pressurization. Because of the pressure exercised under the screw head, this pressurization prevents terminal loosening and/or after application of the screw stem against the low wing, to recover the creep of the conductor screw tightened by the terminal.
However, the U-shape of the pressure device leads to an unbalance during terminal use.
Document DE 40 13 225 also illustrates a screw terminal equipped with a pressure device in the form of a closed cage, where the deformation method is not described.
This invention is aimed at improving the balance of a screw terminal such as those described, while at the same time ensuring improved deformation for the pressure device, partly for the space occupied by the terminal, and partly to respect the elastic limit of the pressure device.
According to this invention the pressure device is composed of two elastic wings symmetrical with the axial plane of the screw, the elastic wings are concave shaped and the head of the screw acts on the head plate to place the pressure device under compression symmetrically when the screw is tightened. The pressure device provides an advantage by forming an interlocked ring with the rigid cage.
The conception of the pressure device is preferably designed so that the concave elastic wings change shape reducing the concavity when the strain created by the screw is increased. The head plate has a sloping or convex shape and the screw head presses on the head plate at a slight distance from the screw axis to facilitate the described reduction effect in the concavity of the sides. The pressure device can be engaged on the neck of the screw through an assembly plate composed of two circular half-sectors, and this can form or act with the elements that maintain the terminal in open position and improved insulation on the side of the opening where the conductor is inserted.
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Bassenonville Denis
Garcia Jose
Grillot Herve
Paggi Serge
Parkhurst & Wendel L.L.P.
Schneider Electric Industries SAS
Ta Tho D.
Tsukerman Larisa
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