Device with axially positionable coil winding

Electricity: magnetically operated switches – magnets – and electr – Electromagnetically actuated switches – Tripping means

Reexamination Certificate

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Details

C335S042000, C335S172000, C335S174000

Reexamination Certificate

active

06300853

ABSTRACT:

This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/DE99/02372 which has an International filing date of Aug. 3, 1999, which designated the United States of America.
FIELD OF THE INVENTION
The invention relates to an overcurrent release having a U-shaped yoke, a coil winding, a pole and an armature, with there being an airgap between the pole and the armature and the coil winding being arranged between the two limbs of the yoke.
BACKGROUND OF THE INVENTION
A device of this generic type is used in non-delayed overcurrent releases such as, in circuit breakers for switching and protection of motors and other loads. These non-delayed overcurrent releases are designed as electromagnetic releases, which essentially include a coil winding, a coil former, an armature, a pole, a plunger, a restraining spring and a yoke. The armature pulls in at a specific circuit breaker rated current, for example at twelve times the rated current for motor protection or at 19 times the rated current for transformer protection. The armature movement in the process acts on a switch mechanism and on a moving switching piece, in order to open the contacts. According to the Standard (IEC60947), the response current must not fluctuate by more than ?20% in this case.
If the adjustment ranges are relatively wide, it is difficult to position the coil winding accurately this is because of to the relatively large supporting cross-sections required, the relatively small numbers of turns, the relatively wide tolerances for the coil and the winding wire and the relatively inhomogenous magnetic field associated with this. Thus, it is difficult; and to position the coil winding sufficiently accurately with respect to the airgap between the armature and the pole in order to make it possible to comply with the response limits in accordance with the Standard. Furthermore, there is a problem in fixing the coil winding in the position with respect to the airgap once this has been determined so that the coil winding is not moved in the direction of the center of gravity of the iron at the rated current or in the event of high short-circuit current; or with the coil being compressed or deformed as a consequence, it often results in no longer complying with the response limits.
For relatively low switching ratings; the coil winding is wound on a coil former. At the upper and lower ends, the coil former is provided with a flange, against which the winding wire rests. Furthermore, the coil formers are generally wound with a number of layers, and the last layer is bound with adhesive tape in order to fix it The coils thus form a compact unit, avoiding the problems mentioned above.
For higher switching ratings, the coils are produced with the winding turns resting on them in order to prevent the coil from being compressed and deformed in the event of high short-circuit currents.
Owing to the use of standard coil formers for the respective size and the fact that they are designed for the geometrically largest coil winding, there is often a gap between the coil former flange or yoke and the last turn of the coil winding. Once the coil winding has been positioned accurately with respect to the airgap between the armature and the pole, one end of the winding is bonded to the coil former flange or yoke in order to fix the coil winding, and the other end of the winding is welded to a connection.
SUMMARY OF THE INVENTION
The invention is based on the object of providing a device having a coil winding which allows the coil winding to be positioned in its axial direction.
The object is achieved by providing an adjusting ring between the coil winding and one of the two limbs of the yoke. This acts as a variable spacer between the coil winding and the yoke this such the position of the coil winding with respect to the airgap can be varied in the axial direction by twisting the adjusting ring.
In one advantageous development of the invention, the adjusting ring has a surface which faces the last winding turn and is matched to the pitch of the winding wire of the coil winding. This allows the coil winding to be supported over a large area toward the yoke. At the same time, the coil winding can be moved axially, with little force being required, by twisting the adjusting ring.
In addition, it is advantageous for the coil winding to be arranged on a coil former.
Inadvertent backwards twisting of the adjusting ring is prevented in a simple manner by providing the adjusting ring with teeth on its innerside which engage with teeth on the coil former.
In a further advantageous refinement, the adjusting ring is provided with an external tooth system. This allows slight movement by hand or by a production machine.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.


REFERENCES:
patent: 4939492 (1990-07-01), Raso, et al.
patent: 5793026 (1998-08-01), Kolberg, et al.
patent: T2-68909431 (1994-05-01), None
patent: A1326449 (1989-08-01), None

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