Movable or removable closures – Up-and-over type; e.g. – moves from vertical to withdrawn...
Patent
1998-12-07
2000-09-26
Stodola, Daniel P.
Movable or removable closures
Up-and-over type; e.g., moves from vertical to withdrawn...
49200, 160191, E05D 1538
Patent
active
061228621
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention concerns a door that can be opened and closed by raising and lowering it vertically, that can be installed against a ceiling and slide up and down on rollers, or that can be tilted or swung up and down. It features a weight-compensation mechanism attached to it at one end and to a fixed point at the other and including one or more helical-spring modules.
Equipping overhead doors with weight-compensation means to maintain the forces need to open and close them weak is known. Such means include "torsion" springs that apply forces to the door by means of cords and weight-compensation shafts and helical springs, both tension and compression.
When helical springs are involved, means of preventing broken sections from flinging out are necessary. Such means can be tubes that telescope in the event of breakage and devices that extend within the spring and intercept the fragments.
The diameter of the tubes must be longer, the longer the diameter of the spring, which depends in turn on its performance curve in that springs intended to accommodate more powerful forces must be wider than those intended to accommodate weaker ones.
Several weak helical tension springs have been paralleled as an alternative to a single more powerful spring. In this approach, however, each individual spring must be provided with a safety-ensuring device of its own extending through it.
The advantage of several parallel springs is that, if a spring breaks, the forces acting on the door will not all be eliminated. Still, a module comprising several springs of specific power or storage capacity will occupy considerable space.
SUMMARY OF THE INVENTION
The present invention is intended to reduce the space needed to accommodate such helical-spring modules.
This object is attained in accordance with the present invention in that the helical-spring module or modules includes or include at least two parallel-loaded coaxial or nested helical springs, whereby the outside diameter of the coil of the inner spring is shorter than the inside diameter of the coil of the outer spring and whereby the coil of one of the springs in a module winds to the left and the coil in the other winds to the right, the two coils crossing each other.
The coaxial arrangement of the two or more springs allows an overall performance curve with a high storage capacity, even in comparison with those of similar larger and more powerful spring or of several adjacent weaker springs, in little space. The mutual proximity of the coaxial or nested springs is particular important and is possible only because of the opposed winding with the coil of one spring crossing that of the other. The springs can accordingly be very close to each other without the coil of one spring engaging the gaps between the coil in the other spring and jamming it.
Each inner spring intercepts any fragments broken off the outer spring and each outer spring constitutes a cylinder surrounding the inner spring, preventing such fragments from flinging out.
When such coaxial tension springs of different diameter are mounted horizontal, they will also prevent each other from sagging. Compression springs on the other hand will help to prevent each other from buckling horizontally, and this function can be augmented with a guide in the form of a tube surrounding them or of a rod extending through them.
The surfaces of the coils that come into contact are protected from friction in one preferred embodiment by a slick intermediate layer, preferably a sleeve of low-friction plastic.
When helical compression springs are employed, they are conventionally secured at the ends. When helical tension springs are employed, their coils can basically be provided with hooks at their ends at an angle to their winding. One preferred embodiment also employs flat-ended helical tension springs thrust over accommodations as disclosed in Europe Patent 0 266 061 B1 and German 3 924 947 C2.
Tension-spring modules of the type illustrated herein at one end of a spring are employed with
REFERENCES:
patent: 3348336 (1967-10-01), Hashagen
patent: 4757853 (1988-07-01), Price
Cohen Curtis A.
Fogiel Max
Stodola Daniel P.
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