Brakes – Operators – Spring
Reexamination Certificate
1998-07-30
2001-05-29
Oberleitner, Robert J. (Department: 3613)
Brakes
Operators
Spring
C188S163000
Reexamination Certificate
active
06237730
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a safety brake which is releasable via an electromagnet.
A safety requirement issued by regulatory bodies demands technical equipment to be provided with two separate braking circuits so that if one braking circuit should fail, a braking operation from the other braking circuit can be provided. This is the case for elevators constructed in accordance with elevator regulation TRA 200 DIN EN 81.
In accordance with the subject matter of German Gebrauchmuster 295 10 828 two brakes are spacially integrated. In this arrangement there are two armatures, two brake disks, two spring arrangements that press the armature disks against the brake disks, and a single electromagnet with a magnetic coil arranged between the armature disks and brake disks. This arrangement provides a functionally safe, inexpensive and compact system that provides two brakes that are independent of one another.
In order to save space and to simplify the brakes while maintaining the safety function of a braking operation, and thereby reduce the cost of brakes, these brakes were further developed as shown in German Gebrauchmuster 296 11 732.3. In this brake the electromagnet comprises a magnetic coil and coil carrier that surrounds a central shaft that is arranged to be axially displaceable, but not rotatable in the brake. In addition, a single armature disk
3
that is axially displaceable, but cannot be rotated in the brake, is arranged axially between one of two brake disks
2
,
11
and the magnetic coil/coil carrier. Springs are tensioned axially between the magnetic coil/coil carrier and the single armature disk
3
.
A disadvantage of this twin circuit brake is that, on account of the placement of the magnetic coil in the region between the rotating brake disks, the heat that is generated on the brake disks during braking bears upon the coil from two sides. Thus, the coil is heated in accordance with the amount of frictional work done during braking. This heating can become significant, particularly in a high temperature environment, for example in warm countries. In order to prevent overheating of the coil it is necessary to limit the braking power correspondingly.
A further disadvantage of this twin circuit brake is that it is necessary to change the entire coil when the brake linings are changed. This means that an inconvenient amount of effort needs to be expended in order to change the parts subject to wear.
Obviously, this twin circuit brake also needs to comply with the aforementioned safety requirement. In particular, malfunction situations (jamming or seizure situations) that can affect the movable parts of the brake should be accounted for.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a two circuit brake that satisfies the aforementioned safety requirement.
Further, it is an object of the invention to provide a two circuit brake in which the heat generated by braking effect of the brake, in particular in the vicinity of electrical components, is as small as possible.
A further object of the invention is to reduce the amount of effort expended in servicing the brake, in particular in the changing of the wearable parts of the brake, such as the brake linings.
The brake should also be constructed in the simplest possible way, so that it is easy to manufacture.
These objects are achieved in accordance with the following description of the invention.
In the two circuit brake in accordance with the invention, the heat that is generated on the brake linings during braking is only conducted to one side of the coil carrier, and then only via the armature disk. The heat can thereafter be released to the environment via the exposed outer side of the coil carrier. In this way the temperatures that occur in the coil carrier are kept relatively low.
REFERENCES:
patent: 4337855 (1982-07-01), Bennett
patent: 4982825 (1991-01-01), Sekella
patent: 5057728 (1991-10-01), Dammeyer et al.
patent: 5154261 (1992-10-01), Tanaka et al.
patent: 5274290 (1993-12-01), Fischer
patent: 24 04 473 (1975-08-01), None
patent: 27 30 168 (1979-01-01), None
patent: 83 31 477 (1985-01-01), None
patent: 34 24 595 (1986-01-01), None
patent: 295 10 828 U (1995-10-01), None
patent: 296 11 732 U (1996-10-01), None
Dropmann Christoph
Schilling Karl
Chr. Mayr GmbH & Co. KG
King Bradley
Oberleitner Robert J.
Wenderoth , Lind & Ponack, L.L.P.
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