US 736677 A
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Description (OCR text may contain errors)
No. 736,677. f PATENTED AUG. .18, 1903.v
APPLICATION FILED MAR. 2, 1903.
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UNITED STATES Patented August 18, 1903.
SPECIFICATION forming part of Letters Patent No. 736,677, dated August 18, 1 903.
Application filed March 2, 1903. Serial No. 145,365. (No model.)
To @ZZ whom it may concern.-
Be it known that I, GASPAR BLOOM, a subject of the Emperor of Germany, and a resident of Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Resistance- Tubes, of which the following is a specification.
My invention relates to devices for use in connection with electric conductors; and .it consists of improved forms of resistancetubes, so called, or tubes which are longitudinally surrounded by the helices of a resistance-coil.
The objects of my invention are to provide as a part of such a device a metallic tube` which shall be capable of resisting a breaking strain, such as might be due to the im` pact resulting from the falling of said tube upon an unyieldin g surface; to provide coats of insulating material which completely inclose said tube and also protect thelatter from oxidation; to provide for the resistancecoil a perfectinsulation by means of material of a relatively very high fusing temperature, and to provide improved means for connecting the ends of the resistance-coil with those of electric conductors.
I am aware that resistance-tubes have hitherto been made of vitrified clay and that resistance-coils have been inclosed within coats of soft enamel surrounding said tubes exteriorly. Such tubes are, however, more frangible than those of my invention, and the coilinclosing enamel is fusible at a temperature which is several hundred degrees lower than that of porcelain or porcelain enamel, which are the materials used in my invention. Furthermore, exposed end parts of the coilwire have been used for connecting other wires thereto, and these frequently were accidentally broken from the device at or near the surface of the insulating material, thus rendering the device entirely useless, the latter differing therein from my improved connections, each of which comprises a exible metallic band which is suitably joined to an end of the coil, ends of said band forming a duplicate connection for a conducting-wire and the device therefore retaining its usefulness, evenv though parts of the band ends should be accidentally broken off. It should be noted also that the band ends, because of their comparatively greater liexibility, are not so readily broken otf as are projecting ends ofvwire. A,
In .thedrawings Figure lis a side elevation of a complete resistance-tube which embodies a form of my invention. Fig. 2 is a central vertical longitudinal section thereof. Fig. 3 is an end elevation of the device; and Fig. 4 is a detail View of a band, a connecting-wire being shown in broken lines.
Corresponding parts in all the figures are denoted by the same reference characters.
Referring to the drawings, l designates a metallic tube, which may be inexpensively made of cast-iron and may be coated internally with anyv suitable protective material, such as a vitriiied insulating substance, and preferably porcelain enamel. A coat 2,0f porcelain, covers the exterior surfaces, including the ends, of the tube l, and upon this is fused a coat 2', of porcelain enamel, upon which is coiled a resistance-wire 3. Flexible bands 4 4, of suitable sheet metal and preferably of copper, are respectively contacted with and preferably connected to the ends of the wire 3. A The material of each band should be longer than is necessary to encircle the device as the latter is thus far formed, and the remaining parts 4' 4' of said material of each band maybe joined together as closely to the tube l as possible, as at 4l', and in any suitable manner, ascrew 5, passing through a perforation in each part 4 and secured by a nut 5', being shown herein as used for the purpose mentioned. The parts 4 extend radially near each end of the tube l a sufficient distance to form clamps 6, the members whereof are perforated near their outer ends. A screw 7 and a nut 7 may be used to close each clamp 6 upon a bent end of a conducting-wire 8, which is shown in broken lines in Fig. 4. An outer coat 2, of fused porcelain enamel, surrounds the resistance-coil 3 and the bands 4 4 and is practically integral with the inner coat 2', thus inclosing the coil 3 in an impervious insulating material.
The porcelain enamel which I use in connection with my invent-ion cannot be fused at a lower temperature than from 1,0000 to 1,200 Fahrenheit, or at a temperature from 600 to 800 above that of the fusing-point of the soft enamel heretofore used for the purpose.
The uses and advantages of my invention will be readily understood and appreciated by those who are skilled in the art to which it appertains. The device as shown and described is simple and durable, provides perfect insulation for the resistance-coil, cannot easily be broken, and provides improved means for its connection to electric conductors. It should be noted that the parts 4 are not of such a nature as to be easily broken from the resistance-tube; but should this occur at the most natural point of breakagenamely, outwardly of the screw 5 and nut 5- the latter members, together with the remainder of the projecting parts 4', will form a clamp which will be well adapted for use for. the same purpose as that for which the clamp 6 is designed. The tube 1, which is simply used as a base member upon which to locate and secure the functionally-required members of the device, being completely inclosed within practically indestructible insulating material, is perfectly protected from oxidation and also from electrolytic action.
I do not desire to be understood as limiting myself to the details of construction and arrangement as herein described and illustrated, as it is manifest that Variations and modifications may be made in the features of construction and arrangement in the adaptation of the device to various conditions of use without departing from the spirit and scope of my invention and improvements. I therefore reserve the right to all such variation and modification as properly fall within the scope of my invention and the terms of the following claims.
Having thus described my invention, I claim and desire to secure by Letters Patentl. Aresistance-tube, comprisinga supporting-tube, a plurality of coatings of insulating material inclosing said tube, a resistance-coil interposed between said coatings, metal strips encircling the supporting-tube between said coat-ings of insulating material and connected to the terminals of the resistance-coil, the ends of said bands projecting eXteriorly of said coatings and forming clamps for connecting the terminals of the coil with the terminals of acircuit, substantially as described.
2. A resistance-tube, comprising a metallic supporting-tube, a plurality of coatings of insulating material inclosing said tube, a resistance-coil interposed between said coatings, metal strips encircling the supporting-tube between said coatings of insulatingmaterial and connected to the terminals of the resistance-coil, the ends of said band projecting exterior-ly ofsaid coatings and forming clamps for connecting the terminals of the coil with the terminals of a circuit, substantially as described.
3. A resistance-tube, comprising a metallic supporting-tube, a plurality of coatings of porcelain enamel surrounding said tube eX- teriorly, a resistance-coil interposed between the coatings of porcelain enamel, and iiexible sheet-metal bands between said coatings of insulating material and connected to the terminals of the resistance-coil, the ends of said bands projecting exteriorly of coatings and forming clamps for connecting the terminals of the coil With the terminals of a circuit, substantially as described.
at. A resistance-tube, comprising a supporting-tube, a plurality of coatings of insulating material inclosing said tube, a resistance-coil interposed between said coatings, metal strips encircling the supporting-tube between said coatings of insulating material and connected to the terminals of the resistance-coil, the ends of said band projecting eXteriorly of said coatings, bolts projecting through said ends and nuts on the ends of said bolts, substantially as described.
In testimony whereof I have signed my name in the presence of the subscribing witnesses.
CHAs. H. DAvIDs, J. C. PYBAs.