US2207291A - Frictionally positioned fireplace damper - Google Patents

Description

y w.'A. HEDSTROM 2,207,291

FRICTIONALLY POSITIONED FIREPLACE DAMPER Filed May 15, 1939 2 Sheets-Sheet 2 INVENTOR flirted 'Wom ATTORN EYS Patented July 9, 1940 PATENT OFFICE FRICTIONALLY POSITIONED FIREPLACE- DAIWPER Wilhelm A. Hedstrom, Seattle, Wash.

Application May 15, 1939, Serial No. 273,772

4 Claims. (01. 126-288) My present invention relates to the art of fireplace dampers and more particularly to a frictionally positioned fireplace damper.

My device consists essentially of a pivoted fire- 5 placedamper so arranged that the gate member proper may be held in any adjusted position within its range from closed to open by friction. Fireplace dampers have been used for long periods. Toooften they are of such construction that the damper is used either in its full open position or full closed position, depending on whether the fireplace is being used or not. In this way the damper merely serves to shut ofi the chimney opening with its resultant draft source when the fireplace is not being used. It has been found, however, that the fireplace with the throat properly restricted in accordance with the amount of flue gases passing therethrough exerts a very marked degree of control on the fire particularly effecting the production of useful heat therefrom. It has been found, for instance, that proper throating by means of a damper can control the smoking of furnaces,-

particularly when windy outside conditions prevail, and it is therefore the purpose of my present invention to provide means for frictionally holding the damper blade in its most efiective adjusting position, and by so doing the damper is not eifected by steps as is so often the case where 80- a chain adjustment is used or where fiat spots are provided in the rotating shaft, but rather to provide a means so that any intermediate degree of adjustment may be accomplished.

Another object of my invention is to provide 85 a damper structure which will permit the damper to be placed well up in the throat of a fireplace so that it will adequately serve to vary the throating effect on'the fire which in turn controls the rate of burning and the amount of hot gases 40 that are allowed to escape up the chimney before they have dissipated their heat by reflection into the room served by the fireplace.

' Another object of my invention is to provide a damper arrangement that will function'properly without regard to the linear expansion occurring when the damper is heating or cooling.

Further, I use no frame or dome with my damper, and thus I have eliminated one of the principal sources of malfunctioning in dampers. 0 Too often the heavy cast iron dome type dampers, when set in masonry, will, by the expansion of the same, cause the functioning parts to bind and fail toact as intended. Then too, there is the ever present danger of continued expansion in the cast iron. This isa phenomenon well.

known, particularly in grate fires, that by repeated heating and cooling the cast iron members will gradually grow. This phenomenon is occasioned by the fact that as the metal expands due to heat, it gradually fails to fully contract to its original dimensions, and as a result, this growth of the cast iron tends to rupture the masonry in which it is set.

With my present structure I avoid these difiiculties in that I do not provide end bearings for 10 my damper blades and the method of mounting the same permits of reasonable movement longitudinally so that no binding or rupturing of the masonry can occur.

A further object is to provide a damper of 15 knock-down type so that it can be put into an existing fireplaceafter the fireplace has been completed, or possibly used for a period. This same characteristic: permits the damper to be taken out for replacement or repair as some- Still another objectof my invention is to reduce the fireplace damper construction to its simplest form so that the cost of manufacture will be reduced to the minimum, thusmaking it possible for persons who might otherwise not be 3 justified in the expense of a conventional damper, to take advantage of their usefulness.

Other and more specific objects will be apparent from the followingdescriptions taken in connection with the accompanying drawings,

wherein 40 Figure 1 is a front elevation of adamper made after the teachings of mypresent invention.

Figure 2 is a cross-sectional view taken along the line 2-2 of Figure 1. v

Figure 3 is a perspective view showing one form of damper blade suitable for use with my damper.

Figure 4 is a fragmentary, front elevation, in

section, showing a -modified form of a friction 50,

hearing. Y I

Figures 5 and 6 are cross-sectional views taken alongsimilarly numbered lines of Figure 4.

Figure 7 is a'view similar to Figure 1 taken in front elevation and shown in section and illus- '55 trating further the adjustable blade feature which my construction makes possible.

Figure 8 is a perspective view showing the assemblies used in my damper.

Figure 9 is a bracketed view showing a modified form of my braking mechanism.

Figure 10 is a bracketed view showing the parts used on the left hand end of Figure 7.

Figure 11 is a cross-sectional view taken along the line HH of Figure '7.

Figure 12 is a perspective view showing the bottom side of my fireplace damper embodying the adjustable length damper blade.

Figure 13 is a View similar in part to Figure 2, but showing a modified form of the frictional engaging mechanism.

Referring to the drawings, throughout which like reference characters indicate like parts, [4 designates the damper blade of my assembly. This, while it may be made of steel plate, is normally best made as a casting of cast iron and of substantially the size of the throat opening. Extending downwardly from the under side of plate M are the alined bearings l6 and I1, and preferably, in order to give rigidity, to the end that the plate itself may be relatively thin, I prefer to have a longitudinally extending rib l8 joining the bearing support members 20 and 2|. Secured within bearings l6 and H as by means of the set screws 22 and 231 are the alined stub shafts 24 and 25. These shafts I prefer to form of hexagonal or octagonal material, although for the purpose a fiuted or keyed shaft might be used. Shafts 2d and 25 are adapted to partial rotation within bearing members 21 and 28. These members are normally built into the masonry when the fireplace is being built and under such conditions it is desirable to key these members in by short rods or pins 30 passing through holes drilled in the ends of the hollow shaft bearing portions 3! and 32. Where it is necessary to install the damper after the fireplace has been built, these are installed by drilling into the masonry and then setting the same in mortar.

It has been found that free turning of shafts 2 and 25 can be-assured against any interference by mortar that might be displaced in the installation by providing caps or packing means P to fit over the ends of the hollow shafts 3| and 32, after the showing particularly of Figures 1 and 4. These caps maybe made of any suitable material and need not necessarily be fireproof in that once the mortar has set in a manner to allow for adequate expansion of the damper assembly when the same becomes heated, they have no further function.

In the form that at present appears most desirable, I obtain my friction securing means by providing on shafts 2d and 25, secured theretoby the deformation of the shafts, the friction wheels 34 and 35. In some instances it is sufficient to bore these slightly smaller than the bell of members El and 28, and then by having shafts 2d and 25 slightly smaller than the bore in the bearing portions 3! and 32, the weight of the damper will hold wheels 34 and 35 in frictional engagement with the internal bore of bells 27 and 28 so that frictional engagement or looking will be obtained. It will readily be understood, it is believed, that by forming bells 27 and 28 with a slight taper and then by coning members 3 and 35 to fit into the same, byproper adjustment greater friction can be provided. In the majority of cases this is not necessary, however, and the simplicity of the straight boring is therefore most desirable.

A modified form of the friction securing means is shown in Figures 4, 5 and 6. Here the bearing member 21a is provided with an external V section groove 38 and a corresponding male section arc ll! is formed preferably as part of blade M, or at least frictionally secured thereto. With such a construction it is desirable that the male section member cover at least a quarter circle after the showing of Figures 5 and 6, so that as the damper is rotated through approximately 90 degrees there will be adequate bearing to at all times assure this desirable frictional adjustment. In Figure 4 particularly'it will be noted that shaft 24 is considerably smaller than the bore of member 21a so that it merely serves as a guide to generally positioning plate l4 without actually serving as a bearing therefor. This is a desirable construction that is used generally throughout my various forms of this friction adjusting means.

In order to provide manual adjustment of these dampers I use a relatively long handle 42 provided with a convenient eye at 43 that will be conveniently below the top opening 44 so that it can be easily adjusted as by a poker or the like.

In the majority of installations it is relatively convenient to install bearing members for my damper when in its extreme adjusted position. One form of this bearing that is at presentmost desirable is shown in Figure 2, and consists of the longitudinally disposed angle irons at 46, 4'! and 58. These can be secured in the masonry either at the time the fireplace is built or later when the damper is installed. Normally it requires only anchoring pins which can either be drilled into the masonry or into the mortar between the bricks with which the same is used.

In Figure 2 it will be seen that member 46 engages the under side of damper plate 14 when the same is in its closed position and the upper side of the damper plate is engaged by angle 41. ,When the damper is given its extreme opposite adjustment, that is, entirely opened, member 48 forms a bottom rack that limits the movement with 4'! providing a stop in addition. It will be apparent, it is believed, that any one of these angles might be dispensed with. However, where conditions permit, the three members are most desirable. 1

Itwill be noted, it is believed, that these angles being separate from each other and disposed so that they can expand laterally, follow out the general plan of my damper in providing against any expansion of installation from either fault of the mechanism or destruction of the masonry to which they are attached.

It will be apparent further, it is believed, that the damper plate I4 may be adjusted to any desired position between full open or full closed, and the friction devices illustrated will hold the same in that adjusted position, thus making it possible for the home owner .to so accurately adjust the damper as to insure the maximum efficiency and control of the fireplace fire, thus over coming the objection of many persons to the fireplace, in that it is quite generally assumed that there is no adequate adjustment of the fireplace. With this present invention a very definite 'control is provided which is reflected in greater comfort and more heat from the fuel consumed.

As a convenient means in adapting my damper plate Hi to throat openings of various lengths, I have provided an adjustable plate 45. This is held in the desired longitudinal adjustment by a plurality of screws 46 operating in slots 48 in a manner that will probably be best understood by a study of Figure 8.

One of the outstanding advantages of this form of damper is its capacity for easy insertion or removal from a fireplace after the same has been used for a period. It will be apparent, it is believed, that stub shafts 24 and 25 are held in position as by the set screws 22 and 23, and.- referring particularly to Figure 7, it will be observed that after the assembly on the right has been put in place the locking of handle 42 to shaft 24 and the further locking of shaft 24 by 5 screw 22 serves to secure friction wheel 34 in its operating position within bell 21 and to thus hold all the operating parts in the desired position for continued operation.

There are certain conditions, particularly where heavy draft is encountered, where it is desirable to increase the holding power of my frictional positioning means. Figure 9, wherein the fixed member, as 28a, is fluted on its inner surface, as indicated at 50, and that the matching interior member as 35a be similarly fluted on its periphery as shown at 52. This fluting should normally have a large number of small teeth, proportionately smaller than illustrated in Figure 9. It is desirable to avoid a geared tooth form, but rather shallow fluting that will permit the free rotary action of the damper member proper, and yet by the interlocking of these fluted portions there will be a greater certainty of holding the damper in its adjusted position. Following the principles employed when the bearing members are smooth, the diameter of fiuted members 28a and 35a must be such that the fiuting portions will only contact at one point and will in no way tend to definitely lock the assembly together, because once the damper is installed member 3511 must be capable of rotation by handle 42, as that is the only means for controlling the same. In Figure I3 I have show-n a slight variation of this arrangement in that while the outer member has the interior fluting 5D, the companion disc 34a is formed with only one outstanding lug or flute 5d. With such an arrangement the interlocking effect can be accomplished for certain positions of the damper, and for other portions of its travel, friction alone can be relied upon. This'glves greater versatility to the device so that it may be installed in such a manner. as to give those niceties of control that are so much desired, and

One form is illustrated in which my holding means has been created to fulfill.

The foregoing description and the accompanying drawings are believed to clearly disclose a preferred embodiment of my invention, but it will be understood that this disclosure is merely illustrative and that such changes in the invention may be made as are fairly within the scop and spirit of the following claims.

I claim:

1. In a fireplace damper, the combination with opposed journals rigid in the fireplace walls, each ofv said journals having a face plate provided with an annular shoulder thereon, of a damper plate having bearing supports thereon, axles insaid bearing supports one end of each axle being supported freely in a journal, and means on said axles frictionally engaging said shoulders for retaining the damper in adjusted positing.

2. In a fireplace damper, the combination with opposed journals in said fireplace walls each of said journals having a face plate rigid therewith and an annular shoulder serrated interior thereof, of a damper plate having bearing supports thereon, axles in said bearing supports, one end of each axle being supported freely in a journal, an exteriorly fluted wheel eccentrically mounted on, and rotatable with, .each axle and adapted for coaction with said face plate whereby a segment only of each Wheel will engage a segment of said shoulder to retain the damper in adjusted position.

3. In a fireplace damper the combination with opposed journals in the fireplace walls, and an exterior flanged annular housing rigid with each journal, of a damper plate having end supports and axles adjustably mounted in said supports and projecting into said journals, an annular member on each axle in frictional engagement with the interior of a flanged housing for retaining the plate in adjusted position, and means for adjusting the plate. I

4. In a fireplace damper, the combination with opposed journals in the fireplace walls, of a WILHELM A. HEDSTROM.

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