US 2130851 A
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Description (OCR text may contain errors)
Sept. 20, 1938. F. LE BARON 2,130,851
FIREPLACE DAMPER Filed March 14, 1958 Patented Sept. 20, 1938 PATENT OFFICE FIREPLACE DAMIER Francis Le Baron, Brockton, Mass.
Application March 14,
This invention relates to improvements in fireplace dampers.
` ,More especially it relates to dampers of the general type in which the control to open or 5 close the damper is by a worm screw within the iiue, turned by a handle shaft which reaches out through the chimney breast tol a location where itcan be reached. The invention provides improvements in the worm supporting and operating mechanism, thereby to avoid difcult operating, or failure of the mechanism to function, which hitherto have been caused by caked accumulations of soot and ashes that foster corrosion. Another benefit of the c-onstruction herein disclosed is that it provides so that the fireplace damper unit may be shipped with its operating parts all assembled ready to be set in the flue, requiring only the easy inserting of the handle to whatever depth will meet the varying conditions of different installations.
Heretofore it has been customary to support the worm wholly or partially on the operating rod, or handle, and to operate the damper by a nut, mounted on the worm and linked to the 25. damper, whose travel has moved the damper.
This has required that the parts of the operating mechanism be detached and knocked down for shipping and warehousing, further requiring a putting of parts together when the installation is being made. After the installation the accumulations of soot and dirt between the travelling nut and the worm tend tov hold moisture within the crevices between nut and worm, and to cake, and foster corrosion, with conse- 35 quent interference with satisfactory operation.
The present invention has among its objects to provide for mounting an effective worm in the damper casing, independently of any operating rod, the latter being merely a sort of key to be i04 inserted at the time of installation,-and being, indeed, removable so as to be kept out, if desired, and inserted only at will. This makes a damper which may be operated more easily than in present installations where an operating rod has to support the front end of the worm.
These objects and results may be attained, in connection with a fireplace dome having top opening, and damper therefor of conventional construction, by providing, on the cast iron casing which constitutes the dome, journals for the front and back cylindrical ends of a stout shaft whose mid-portion crosses below the dome and has a worm thread. The front end of this shaft has an axial non-round hole which is accessible, through a hole at the axis of the journal, to
193s, ser-iai No. 195,751
permit the entering of an operating non-round rod or key far enough for the front end of this key-rod to stand in proper relation to any of the different chimney breast settings to which it may likely be desired to fit the damper, so that its handle end projects through the breast and stands in a convenient and accessible position. The shaft with worm, thus journaled within the dome, is xed in position, independent of the operating rod and requiring no support therefrom.
A travelling rider-plow of peculiar construction is threaded on and operated by the worm, being held non-rotatable with respect thereto by a pair of trunnions held in a yoke which is linked to a swinging part of the damper. The peculiarity of the rider is that it engages around less than the full 360 of periphery of the worm, but covers the upper and lateral surfaces thereof, and has its under side open. The rubbing of threads of the worm, and the plowing cf matter on their surfaces by the leading edges of the horizontal bottom face, at the sides of the bottom opening of the rider, enable gravity to extract soot and dust, etc., whenever such foreign elements are loosened by the rider-plow in its movements along the worm.
By mounting the worm independently of the operating rod, the worm with its connections to the damper and casing may be completely assembled at the factory, and the unit thus complete may be stored and be shipped with the worm holding the damper securely to its seat. The operating shaft adds nothing to the size of package. It may be inserted at the time of in.- stallation, being readily adjustable to suit particular requirements as to forward projection from the casing.
It is intended that the patent shall cover, by suitable expression in the appended'claims, Whatever features of patentable novelty exist in the invention disclosed.
In the accompanying drawing:
Figure 1 is a side elevation, in medial vertical section, of a fireplace damper embodying features of the invention, mounted in the iiue above a fireplace; and
Figure 2 is a front elevation, in section on 2 2 of Figure 1.
Referring to the drawing, the fireplace dome and damper frame HJ may be of conventional type, shape and size for being mounted across the lower end of a vertical chimney iiue l2 above the fireplace I4, with base iiange I5 projecting between bricks of the chimney breast, or otherwise secured in a horizontal plane, for maintaining the position of frame I0. The front and end walls of the frame extend from the ange at upward inclinations from horizontal. In' the particular instance portrayed, to which however the invention is not limited, the front wall extends inward and upward approximately at a 45 angle to the plane of the base flange. The end walls rise more nearly vertical. Their top edges run down from the top edge of front wall to near the plane of the base flange at the rear, and, with the edge of the front wall, they provide a seat for the cover or damper I8 which may loe` loosely hinged at the rear by engagement of lugs 28, 20 in the hook elements` 22, 22 on the frame.
The damper I8 is operable between fully closed and fully open positions, with positive control in each direction, so that the damper may be adjusted to stand in any intermediate position. To this end, a shaft 23 whose surface is a wornr24, isV rotatable within frame I0, and a non-rotatable rider 25S travels along the worm, and is connected by yoke-link 28 to move the damper I8.
According to the invention, the shaft carrying the worm 241s mounted independently of its axial key operating. rod 38, being `iournaled at its rear end in bearing 32, and at its front end in bearing 34'. These bearings are cylindrical. They are in blocks mounted on the interior faces of the dome; and they enclose the cylindrical end4 portions of the shaft. Opposite the front bearing the thin cast iron casing of the dome has a sufcient hole for passage of the operating rod. The adjacent endv of the shaft has an axial nonround hole 36 within which the non-round rod may be inserted to the desired degree, to whatever depth is likely to be needed for desired position of its handle end outside of;` the chimney breastl Rider 28' engages around only the upper and side portions of the worm, leaving an opening 2l at-the-under side of the rider exposing the under surface of the worm, through which opening soot, dust, etc. may fall by gravity as it is loosened by the rider in its travel. The rider has trunnions 38, 38 projecting at opp-osite sides intoholes 48, 48,
in the spread branches of an end yoke y42, on the link 28. The other end of the link is pivotally conneotedto damper I8 at 44.
It will be` apparent that the frame I8, damper I8', shaft 23? journaled with worm 24", rider 2.6 and'link 28 may all be assembled at the factorywhere they aremade, and be shipped as a unit, in operating condition, tothe place of installation. Before packing the worm may be operated to draw the damper closed; and it will be held securely so during transit. The operating keyrod 30 may be conveniently enclosed with the unit, tofbe quickly and easily thrust into theA axial hole to the proper depth, at the time of installation, so that its handle 3| will stand eX- posed in convenient location above the fireplace.
By rotation of the rod 38 the worm 24 is turned for opening and for closing damper I8, and the non-clogging rider 26 has positive drive for rubbing internally over obstructive foreign matter; and it has effective provision for elimination of such matter, as that becomes gradually loosened, by dropping it out of the midst of the rider.
The rider. preferably envelops about three fourths of the angular distance around the worm. This is enough to retain its position on the worm, against lateral stress or reaction; and is enough to give good grinding action, and good freedom of opening for gravity to extract debris which has become loosened by the turning of the worm within the rider. The sharp edges of the bottom surface of the rider constitute a sort of plow, which can scrape from the threads of the worm any matter which may have becomey caked on those threads. When thus loosened, or.v if loosened. by the frictional grinding of riderthreads on worm-threads within the rider, any such matter can fall away from the mid-portion of the rider.
I claim as my invention:
l. A fireplace damper comprising, in combination, a dome with openingtherethrough for a passage between fireplace and flue; a damper mounted onv the dome; a shaft extending across said dome, formed exteriorly as a. worm, and adapted at its front'endto be engaged by arctative driving element; a rider on the worm, engaging its threads and adapted to travel along'- it' when the worm is rotated; meansV connecting said rider 'withv the damper and means holding the rider against rotation; said rider being an element which is' curved aroundv1 the worm;.and envelops a partof the periphery of a short portion of the length of the worm, saidpart being less than the full periphery of the worm and leaving exposed the under side of the-worm under thev rider, for gravity fall of debris from the Vworm threads.
2. A fireplace damper as in claim 1 wherein said enveloped part of the periphery is the upper half and more, but is less than the whole, of the periphery of a short portion of the length ofthe worm,.the part so enveloped'havingV angu-` lar extent great enough to prevent lateral. removal of the rider fromthe worm.
3. A fireplace damper as in claim 1, whereinV the rider has an interior threadzfor engaging the worm; and the. interior and exterior surfaces ofA said rider make an edge, where the envelopingof the worm ceases, riding inthe'thread groovev close to the worm. and constituting a;- scraper for foreign matter thereon.
FRANCIS LE BARON'.