US3168028A

US3168028A - Damper blade and assembly

Info

Publication number: US3168028A
Application number: US199950A
Authority: US
Inventors: Francis M Booth; William M Kane
Original assignee: FRANK M BOOTH Inc
Current assignee: FRANK M BOOTH Inc
Priority date: 1962-06-04
Filing date: 1962-06-04
Publication date: 1965-02-02
Anticipated expiration: 1982-02-02

Description

Feb. 2, 1965 F. M. BOOTH ETAL 3,

DAMPER BLADE AND ASSEMBLY Filed June 4, 1962 BY WILL/AM M. KANE 8. L, 277%.Zafi.

A 7 TOP/V5 VS United States Patent Ofifice 3,168,028 Patented Feb. 2, 1965 3,168,028 DAMPER BLADE AND ASSEMBLY Francis M. Booth and William M. Kane, Marysville, Calif, assignors to Frank M. Booth, Ine, Marysville, Calif., a corporation of California Filed June 4, 1962, Ser. No. 199,950 3 Claims. (Cl. 98-110) This invention relates to a damper blade of the general type in which a metal blade includes coaxial shaft extensions secured thereto and projecting from two opposite edges of the blade for supporting the blade for rotary 'movement about the axis of said extensions.

Blades of the above general type have normally been formed with a channel extending across each blade from one of the aforesaid two opposite edges to the other, which channel opens outwardly of one side of each blade, and a stub shaft has been positioned within said channel at each of the two opposite ends thereof with each shaft projecting outwardly of the edge of the blade adjacent thereto. Up

to this point, the present invention employs the same structure.

Heretofore the shafts have each been secured to each blade by use of centrally arched metal straps. One strap has been positioned to extend across each shaft with the shaft projecting laterally into the arch, and the ends of each strap have been welded to the blade at opposite sides of the channel that is in the damper blade. strap is drilled to provide an opening through the arch Each thereof, and each opening so drilled is tapped for a screw. After each shaft has been positioned in the ends of the channel between the latter and the arch in each strap, a I set screw is threadedly extended through the tapped opening in said arch and into engagement with the shaft. In some instances a single shaft may be in the blade channel projecting at its ends from two opposite edges of the damper blade, but the same set screw and strap structure is used to secure the shaft to the blade.

Thus, by the method and structure heretofore employed, six separate steps are required to secure each of two stub shafts to a damper, and the straps, screws and welding vibration and noise in some instances, and the fact that the screws project from the blade also subjects them to being injured, as well as frequently causing injury to workmen installing the blades, since these screws have relatively sharp edges.

One of the objects of the invention is the provision of a blade and shaft assembly that overcomes the above men- ,tioned objections to the conventional blade and shaft assemblies.

One of the objects of the present invention is the provision of a shaft mounting for a damper blade that is stamped and cut as an integral part of each blade.

Another object of the invention is the provision of a shaft mounting for a damper blade that is formed to frictionally hold each shaft rigid with the blade at substantially uniform tightness far exceeding any strain that may be placed on the blade when each blade is in normal use.

A still further object of the invention is the provision of a shaft mounting for securing blade supporting shafts to damper blades, that is formed to preclude interference with the smooth flow of air across either of the two opposite sides of each blade.

Other objects and advantages will appear in the description and drawings.

In the drawings,

FIG. 1 is an isometric view of a typical installation of damper blades.

FIG. 2 is an enlarged elevational view of one end of a damper blade showing the shaft mounting and a shaft, as seen from one side of the blade.

FIG. 3 is an end elevational view of the portion shown in FIG. 2.

FIG. 4 is a cross sectional view taken along line 44 of FIG. 2.

FIG. 5 is a cross sectional view of the blade taken along line 5-5 of FIG. 2, a shaft being shown in elevation.

FIG. 6 is a semidiagrammatic perspective view illustrative of a method of forming the shaft securing portion of the blade.

Referring to FIG. 1 -a fire damper is illustrated in which a plurality of corresponding damper blades, generally designated 1, are supported in parallel side by side relation in a row. Coaxial stub shafts 2 are secured to each blade 1 at opposite ends thereof, which shafts project oppositely outwardly of each blade at said ends, and the projecting ends of the shafts 2 are rotatably supported in bearings carried by side frame members 3 that may support the blades in air ducts or wherever desired.

The blades of each assembly, such as illustrated in FIG. I carry arms 4 projecting from one of the corresponding sides thereof, and which arms may, in turn, be pivotally connected with a single link or bar 5 for simultaneously moving the blades to the desired position within a duct, and a holding rod 6 will hold the blades in said positions against the resistance of spring 7 that tends to move the blades to closed position. A fusible link 8 positioned in the air stream will melt to release the holding rod 6 upon a predetermined elevation in temperature in the stream, whereupon the spring 8 will function to automatically move the blades to closed positions.

The present invention is not concerned with the control means employed, or Whether the damper is a fire, mixing or other damper. However, the assembly illustrated in FIG. 1 emphasizes the importance of a secure connection between the shafts and the damper blades, and also the alignment of the shafts on each blade so that the shafts will turn freely in the bearings.

The present invention is particularly concerned with the means on the blades for mounting the shafts that support the blades for rotation about the axis of the shafts 2, and also the blade-shaft assembly.

Insofar as the method of making the blades, and the blade-shaft assemblies are concerned, each blade illustrated in FIG. 1 is oblong in outline and is formed with a channel 9 extending longitudinally from end to end thereof intermediate the longitudinally extending edges of the blade. This channel will function to reinforce the blade against transverse bowing, and also provides a seat for the shafts.

In FIG. 6 one end portion of a blade 1 is positioned over a die generally designated 10 that includes a pair of axially spaced elongated die elements 12 rigidly supported on similarly spaced die blocks 13 that, in turn, are held in properly spaced relation on a base plate 14. The adjacent ends of said elements 12 terminate approximately even with the adjacent sides of the die blocks.

An end portion of the blade 1 is adapted to be positioned, with the channel 9 opening downwardly, over the die with elements 12 seated within the channel 9. The cross sectional contours of the elements 12 where they are received in channel 9 are substantially complementary to the inner surfaces of the channel 9.

A hold-down member generally designated 15 may include a vertically reciprocable plate 11 carrying a pair of channels adapted to receive the convex side of the channel 9 when the latter is in'a position receiving the die elements 12, as seen in FIG. 6. Plate 11 is rigid with the blocks and is formed with a central opening 17 through which a vertically reciprocable punch 18 is adapted to move. This punch element has a lower edge that extends longitudinally of elements 12 and the punch element is adapted to move downwardly between elements 12 to shear the walls of channel 9 to the planar blade portions extending outwardly therefrom, along spaced lines .25 (FIG. 2) to a position projecting to the side of the blade opposite to the remainders of the channel walls, whereby the portion 19 will form an elongated bridge piece extending between the pair of cuts that are at the ends of the portion 19.

The parts 20 of blade 1 at opposite sides of the portion 19, and that integrally connect the bridge piece 19 with the blade, will automatically be drawn out of the plane of the blade to the same side thereof as the bridge piece, and are a part of the latter. These parts 20 have gently curved surfaces leading from the planar surfaces of the blade at substantially less than right angles relative to said planar surfaces as seen in FIG. 4, so as to function in generally the same manner as an airfoil, to pass air thereover and past the bridge piece, without causing objectionable turbulence and without causing noise or vibration.

The ends of the bridge piece 19 at points 22 (FIGS. 2, 3, adjacent to the cuts 25 or the lines of said cuts, are automatically drawn to form concavely extending surfaces, transversely of the bridge pieces 19, that are adapted to uniformly and more fully and closely engage a damper mounting shaft 2 than the portion of the bridge piece between the said portions at points 22, as will later be explained. Y

The lower edge of punch 18 may be slightly curved, in transverse, cross sectional contour, so as not to score the metal of the portion 19' and so that the metal of portion 19 will have a concave contour facing the plane of, the blade, and which is opposite to the contour of the channel 9 in the remainder of the blade. a

The distance, at a right angle to the planeof blade 1, between the bottom wall of channel 9 that extends away from the bridge piece 19, and the concave surfaces of the bridge piece that face the plane of the blade, is such that the shaft 2 must be forcibly pressed or driven into channel 9 and across the gap between the cuts 25.

FIG. 1 shows shaft 2 at each end of each blade 1, while FIGS. 2-5 also show the shaft in position at one of the ends of a blade. The structure at opposite ends of each blade is identical.

Each shaft 2 has been forced longitudinally thereof to a position in which the shaft extends into the channel 9 at opposite ends of the bridge piece and across the gap that is formed by each pair of cuts 25. The portions 21 of the bridge piece at opposite ends thereof most tightly engage one of the sides of shaft 2 with substantially uni form pressure while the channel walls at opposite ends of the bridge piece, and outwardly of said ends, will engage the opposite sides of the shaft with similar pressure.

The bridge piece is stamped to one side of the plane of the blade such a distance that it will cooperate with the channel walls engaging the shaft at the ends of the bridge piece, to frictionally hold the shaft against rotary movement relative to the damper blade and against axial or pulling movement under any conditions that may be encountered in actual installations. In actual practice, where standard 95 shafts are used, and the walls of channel 9 are formed for such shaft, the mounting socket that comprises a bridge piece 19 and the channel walls at the end thereof are so designed to rigidly retain each shaft in each such socket against axial movement of each shaft relative to the blade at over a four hundred pound pull, and to rigidly hold each shaft against rotary movement relative to the blade at over seventeen inch pounds torque.

The shafts 2 may obviously be simultaneously fitted on each blade, and both bridge pieces may be simultaneously formed. The die and punch of FIG. 6 are not intended to show all elements that may be used, since the holddown plate, for example, may be yieldably held against the blade by springs, and conventional means may be employed to mount the die, punch and hold-down structure in a punch press.

It should also be noted that parts 23 of bridge piece 19 connect with the sloping portions extending away from the blade in a direction that extends toward the axis of the shaft, which insures a more secure engagement-between the bridge piece 19 and the shaft, irrespective of variations in the temperature of the air or'gas passing over the blades, and this depression of the bridge piece between portions 20 does not create any objectionable turbulence in the air stream.

It is to be understood that the claims appended hereto are intended to cover all changes'and modifications of the example of the invention herein chosen for the purpose of disclosure which do not constitute departures from the spirit of the invention and the scope of the claims.

'We claim:

1. In an elongated sheet metal damper blade formed with a channel extending longitudinally thereof having walls of uniform substantially semi-cylindrical cross-sec tional contour from end to end thereof projecting to one side of said blade providing a concave substantially semicylindrical inner surface adapted to follow and engage the outersurface of a shaft having approximately the same cylindrical contour, said blade having planar por= tions respectively at opposite sides of said channel, and said channel being open'at the ends of said blade:

(a) the walls of said channel being formed at a point intermediate the ends of the latter with a gap of sub stantial width longitudinally of said channels;

(b) a bridge piece integral with and stamped from Said blade extending longitudinally of said channel and across said gap and projecting to the o posite side of said blade that is opposite to said one side thereof;

(c) said bridge piece including side portions of similar size extending generally toward each other from the planar portions at opposite sides of said channel at angles relative to said planar portions that are respectively substantially less than a right angle, and

(d) said bridge piece further including an intermediate portion integral with and connected with said side portions at the ends of the latter that are remote from said planar portions, said intermediate portion being formed with an inner surface of cylindrical crosssectional contour at each of the ends of said intermediate portion axially of the channel and said last mentioned surfaces being concentric with and spaced from the axis about which said semi-cylindrical sur-- face of said channel is developed a distance sufricient to coact with said semi-cylindrical surface that is at opposite sides of said gap for tightly gripping the outer cylindrical surface of such shaft upon driving suchshaft into said channel longitudinally of the latter, and I a (e) a cylindrical shaft in said channel having its outer cylindrical surface tightly gripped by said semi-cylindrical surface of the walls of said channel and the cylindrical surface of said intermediate portion of said bridge piece against axial and rotary movement of said shaft relative to said bladeunder forces substantiallyexceeding those encountered in normal and continued operation of said damper blade,

(f) said shaft extending axially outwardly of said channel to provide a free end for mounting in a bearing.

2. In a damper blade as defined in claim 1:

(g) said intermediate portion being in a position closer to said axis about which said semi-cylindrica1 surfaces are developed than the said outer ends of said side portions, and

(h) extensions integral with said side portions at their said outer ends extending generally toward said axis integral with and supporting said intermediate portion in said position.

3. In an elongated sheet metal damper blade formed with a channel extending longitudinally thereof having walls of uniform substantially semi-cylindrical cross-sectional contour from end to end thereof projecting to one side of said blade providing a concave substantially semicylindrical inner surface adapted to follow and engage the outer surface of a shaft having approximately the same cylindrical contour, said blade having planar portions respectively at opposite sides of said channel, and said channel being open at the ends of said blade:

(at) the walls of said channel being formed with a pair of gaps respectively adjacent to but spaced from the ends of said blade, said gaps being of substantial width longitudinally of said channel;

(b) a pair of corresponding bridge pieces integral with and stamped from said blade extending longitudinally of said channel and across said gaps respectively, and projecting to the opposite side of said blade that is opposite to said one side thereof;

(c) said bridge pieces including side portions of similar size extending angularly relative to said planar portions to said opposite side of said blade, each extending from each planar portion with which it is connected at substantially less than a right angle, and from points substantially equally spaced outwardly of the respective sides of said channel a substantial distance;

(d) said bridge portions each further including an intermediate portion integral with said side portions respectively formed with inner surfaces of cylindrical cross-sectional contour concentric with and spaced from the axis about which the semi-cylindrical surface of said channel is developed distances sufficient to coact with said semi-cylindrical surface of said channel at opposite sides of said gap to respectively tightly and frictionally grip the outer cylindrical surface of such shaft upon driving a pair of such shafts endwise into said channel at each of the ends of the latter;

(2) a pair of cylindrical shafts so driven in said channel having their outer cylindrical surfaces tightly gripped by said semi-cylindrical surface of said channel and the cylindrical surfaces of said intermediate portions against axial and rotary movement of said shafts relative to said blade under forces substantially exceeding those encountered in normal and continued operation of said damper blade;

(f) said shafts extending axially outwardly of said channel at the opposite ends of the latter to provide free cylindrical ends for mounting in bearings;

(g) said intermediate portions being in positions spaced from but closer to said axis about which said semicylindrical surface of said channel is developed than the distances of the outer ends of said side portions that are remote from said points are spaced from said axis;

(h) extensions of said side portions at their said outer ends extending generally toward said axis integral with and supporting said intermediate portions in their said positions.

References Cited by the Examiner UNITED STATES PATENTS 1,230,882 6/17 Filbey 126-292 1,288,706 12/18 Shanahan et a1. 29-515 1,480,949 1/24 Olinger 126-292 1,675,404 7/28 Cohn 126-292 1,734,013 10/29 Jones 126-288 2,427,393 9/47 Eckel 29-515 2,572,491 10/51 Keilwitz 126-288 ROBERT A. OLEARY, Primary Examiner.

WHITMORE A. WILTZ, JAMES W. WESTHAVER,

Examiners.

Claims

1. IN AN ELONGATED SHEET METAL DAMPER BLADE FORMED WITH A CHANNEL EXTENDING LONGITUDINALLY THEREOF HAVING WALLS OF UNIFORM SUBSTANTIALLY SEMI-CYLINDRICAL CROSS-SECTIONAL CONTOUR FROM END TO END THEREOF PROJECTING TO ONE SIE OF SAID BLADE PROVIDING A CONCAVE SUBSTANTIALLY SEMICYLINDRICAL INNER SURFACE ADAPTED TO FOLLOW AND ENGAGE THE OUTER SURFACE OF A SHAFT HAVING APPROXIMATELY THE SAME CYLINDRICAL CONTOUR, SAID BLADE HAVING PLANAR PORTIONS RESPECTIVELY AT OPPOSITE SIDES OF SAID CHANNEL, AND SAID CHANNEL BEING OPEN AT THE ENDS OF SAID BLADE: (A) THE WALLS OF SAID CHANNEL BEING FORMED AT A POINT INTERMEDIATE THE ENDS OF THE LATTER WITH A GAP OF SUBSTANTIAL WIDTH LONGITUDINALLY OF SAID CHNNELS; (B) A BRIDGE PIECE INTEGRAL WITH AND STAMPED FROM SAID BLADE EXTENDING LONGITUDINALLY OF SAID CHANNEL AND ACROSS SAID GAP AND PROJECTING TO THE OPPOSITE SIDE OF SAID BLADE THAT IS OPPOSITE TO SAID ONE SIDE THEREOF; (C) BRIDGE PIECE INCLUDING SIDE PORTIONS OF SIMILAR SIZE EXTENDING GENERALLY TOWARD EACH OTHER FROM THE PLANAR PORTIONS AT OPPOSITE SIDES OF SAID CHANNEL AT ANGLES RELATIVE TO SAID PLANAR PORTIONS THAT ARE RESPECTIVELY SUBSTANTIALLY LESS THAN A RIGHT ANGLE, AND (D) SAID BRIDGE PIECE FURTHER INCLUDING AN INTERMEDIATE POTION INTEGRAL WITH AND CONNECTED WITH SAID SIDE PORTIONS AT THE ENDS OF THE LATTER THAT ARE REMOTE FROM SAID PLANAR PORTIONS, SAID INTERMEDIATE PORTION BEING FORMED IN AN INNER SURFACE OF CYLINDRICAL CROSSSECTIONAL CONTOUR AT EACH OF THE ENDS OF SAID INTERMEDIATE PORTION AXIALLY OF THE CHANNEL AND SAID LAST MENTIONED SURFACES BEING CONCENTRIC WITH AND SPACED FROM THE AXIS ABOUT WHICH SAID SEMI-CYLINDRICAL SURFACE OF SAID CHANNEL IS DEVELOPED A DISTANCE SUFFICIENT TO COACT WITH SAID SEMI-CYLINDRICAL SURFACE THAT IS AT OPPOSITE SIDES OF SAID GAP FOR TIGHTLY GRIPPING THE OUTER CYLINDRICAL SURFACE OF SUCH SHAFT UPON DRIVING SUCH SHAFT INTO SAID CHANNEL LONGITUDINALLY OF THE LATTER, AND (E) A CYLINDRICAL SHAFT IN SAID CHANNEL HAVING ITS OUTER CYLINDRICAL SURFACE TIGHTLY GRIPPED BY SAID SEMI-CYLINDRICAL SURFACE OF THE WALLS OF SAID CHANNEL AND THE CYLINDRICAL SURFACE OF SAID INTERMEDIATE PORTION OF SAID BRIDGE PIECE AGAINST AXIAL AND ROTARY MOVEMENT OF SAID SHAFT RELATIVE TO SAID BLADE UNDER FORCES SUBSTANTIALLY EXCEEDING THOSE ENCOUNTERED IN NORMAL AND CONTINUED OPERATION OF SAID DAMPER BLADE, (F) SAID SHAFT EXTENDING AXIALLY OUTWARDLY OF SAID CHANNEL TO PROVIDE A FREE END FOR MOUNTING IN A BEARING.