US2210869A

US2210869A - Damper

Info

Publication number: US2210869A
Application number: US173344A
Authority: US
Inventors: John M Larson
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1937-11-08
Filing date: 1937-11-08
Publication date: 1940-08-06
Anticipated expiration: 1957-08-06

Description

Aug. 6, 1940. J. M. LARsoN 2,210,869

DAMPER Filed Nov. a, 1951 23 23 t ,L ,L z

INVENTOR John M. Larsom BY A9/WMM ATTORNEY Patented Aug. 6, 1940 UNITED [STATI-:s

PATENT. oFFlcs DAMPER Application November s, 1931, serial No. 173,344

4 Claims.

This invention relates to dampers and more particularly to the type of damper employing a plurality` of blades which are actuated together by a cross connection.

In order that the blades of a damper of this type may be opened and closed together it has been customary to secure an actuating bracket toeach blade. 'I'hese actuating brackets are pivoted to a cross actuating member at a point so located relative to the blade that the actuating member will clear the blades in all the operative positions of the blade. It is common practice to use a at bar, pinned to each actuating bracket, as the cross connection. A damper motor either .actuates the cross connection or is operatively connected to one of the blades by a mechanism apart from the cross connection.

'I'he difliculty encountered with this construction lies in the extreme care which must be employed in manufacture if proper operation is to be attained. Dampers of this type are generally built for a particular installation, making it impractical to tool up for quantity production on a damper of certain dimensions. Consequently the parts are constructed by hand and all dimensions must be laid out individually. If with the usual stili' cross connection, one bracket is pivoted to the cross connection at a slightly greater distance from the damper pivot than an adjoining damper. bracket, the pivot points of the brackets will move through unequal distances, as the damper blades are moved from one position to another, thereby causing binding. Also, with the usual stiii cross connections, if the .brackets of all of thedamper blades are not parallel, binding will result. 'I'his binding throws additional load on the damper motor and results in improper settingsv of the blades. In addition to the binding which resulted when dampers of this type were not accurately constructed,'-the blades of such dampers would also not all close together unless extreme care was taken in the manufacture of the damper.' For instance, unless all of the brackets Were attached to the cross connection at properly spaced points, one pair of blades would reach closed position before others of the blades, thereby preventing complete closure of the damper, which of course is objectionable in many types of installations. Also, in many instances, even through a damper of this type would be properly constructed at the factory, it would be bent or sprung while in transit from the factory to the job or during installation, which would result in the damper then binding or failing to close completely.

An object of this invention is to provide a damper of the type employing a cross connection to actuate a plurality of blades in which the above difficulties are obviated.

A further object 0f the invention is to provide a damper comprising a plurality of blades operated simultaneously by a cross connection, of such construction as to eliminate binding when shifting from one damper position to another.

Another object is to provide a damper of the above mentioned type in which the blades may be readily adjusted during installation so that they all close together.

Another object is to provide a damper in which the degree of skill and care that must be employed in manufacture and installation is reduced.

Other objects will appear from the following description and the appended claims. For a full disclosure of my invention reference is made to the following detailed description and to the accompanying drawing in which:

Figure 1 is a plan view partly in section of a damper embodying the invention,

Figure 2 is a perspective view showing an actuating bracket together with a trunnon and a p'ortion of the actuating rod, and

Figure 3 is a sectional view through the bracket, trunnion and rod taken on line 3 3 of Figure 1.

The damper frame is generally illustrated at I0 and comprises a rectangular frame of channel section adapted to be placed in a duct or the like through which it is desired to control the now of air. Plvoted in frame I IJ are damper blades I I, I2, and I3 which when in the position shown in solid lines in Figure 1 are eiective to close the opening inside the frame I0. The blades I I, I2, and I3 are similar and each extends longitudinally across the opening. Rods I4, I5, and I 6 are suitably secured to blades II, I2, and I3 and extend into holes drilled in frame I0 to form bearings about which the blades may rotate. Angle pieces I1 and I8 are secured to the frame to form abutments against which the outside blades I I and I3 rest when closed and serve both as stops for the blades and as a means to close the opening more tightly. The longitudinal edges of the blades are so formed as to interlock with the adjoining blade.

Actuating brackets I9, 20, and 2I are secured to blades II, I2, and I3 by any suitable means as by riveting as at 22, 23, and 24. As shown in Figure 1 these brackets are so shaped that when the blades are in their open position, as shown in'dotted lines, the actuating rod 25 Will clear the edges of the blades. As thus far described the damper is of conventional construction.

The damper blades are actuated simultaneously by actuating rod 25 which is pivotally connected to brackets I9, 20, and 2| by

trunnions

26, 21, and 28. Rod 25 while 0f sufficient diameter not to buckle in operation is nevertheless rather ilexible.

Figures 2 and 3 illustrate the manner in which the actuating brackets are attached to rod 25. Trunnion 21 passes through holes 30 in bracket 20, the holes being suillciently larger than the .trunnion to permit free rotation. Rod 25 passes through hole 3| in trunnion 21 andis secured therein by set screw 29.

With the bracket, trunnion and rod as described it is only necessary to loosen all the set screws, close all the blades so that they all close perfectly, and then tighten up the set screws. 'I'he adjustment of the damper is complete. By this arrangement, it Will be apparent that less care need be taken in the manufacture of the damper than for dampers of ordinary construction thereby reducing the cost of the damper While at the same time insuring proper operation o! the damper after installation.

By making rod 25 light and exible, inaccuracies of manufacture or slight misalignment of the parts due to shipping and handling will not cause the mechanism to be sti in its operation. Ii' trunnion 21 is located a slightly greater distance from pivot rod I5 of blade I2 than the other trunnions 26- and 28 are from the pivot points of their blades, rotation of the blades will result in trunnion 21 traveling in a greater arc than trunnions ,.26 and 28. Then, if the trunnions were in line in the first position, rod 25 will dex on movement away from this position. A similar result will occur if the effective lever arms of the various trunnions about their associated blade pivots are not parall'el. Since rod 25 is of small diameter withrespect to the distance between trunnions it will flex easily causing little binding or friction.

It will be seen that a damper mechanism has been provided which is easily adjusted on thejob to close tightly, which is smooth and easy in operation, and which is economical to manufacture because extreme accuracy of construction is not required.

While one embodiment of the invention has been described it is to be understood that it could take other forms apparent to those skilled in the art and should be limited only by the appended claims and prior art.

I claim as my invention:

1. In a damper mechanism, in combination, a damper frame adapted to be positioned in a passage through which the flow of medium is to be controlled, a plurality of damper blades pivotally mounted in said frame and associated with each other in a manner to cooperate with each other in controlling the ow of medium, a bracket member attached to each damper blade, each bracket member extending beyond the edgeof its associated damper blade, all of the bracket 'members being in alignment, and a connecting member attached to each bracket member for actuating said damper blades in unison, said connecting member comprising a continuous exible rod adapted to be stressed longitudinally in both tension and compression to thereby actuate said damper blades in either direction, flexing of saidA connecting member during movement of said damper blades compensating for irregularities in construction of the damper mechanism and preventing binding of said blades by said connecting member.

2. In a damper mechanism, in combination, a damper frame adapted to be positioned in a passage through which the iiow of medium is to be controlled, a plurality of damper blades pivotally mounted in said frame and associated with each other-in a manner to cooperate with each other in controlling the flow of medium, a bracket member attached to each damper blade, each bracket member extending beyond the edge-of ,its associated damper blade, all of the bracket members being in augment, a connecting member attached to'each bracket member for actuating said damper blades in unison, said connecting member comprising a continuous exible rod adapted to be stressed longitudinally in both tension and compression to thereby actuate said damper blades in either direction, flexing of said connecting member during movement of said damper blades compensating for irregularities in construction of the damper mechanism and preventing binding of said blades by said connecting member, and means for individually adjusting each of said bracket members relatively to said connecting member. Y

3. In a damper mechanism, in combination, a damper frame adapted to be positioned in a passage through which the flow of medium is to be controlled, a plurality of damper blades pivotally mounted in said frame and associated with each other in a manner to cooperate with each other in controlling lthe ow of medium, a bracket member attached to each damper blade, each bracket member extending beyond the edge of its associated damper blade, all of the bracket members being in alignment, a trunnion carried by each bracket member, a connecting member passing through each trunnion for actuating said damper blades in unison, adjustable means for securing said trunnions to said connecting member, said connecting member being flexible and being adapted to be stressed longitudinally in both tension and compression to thereby actuate said damper blades in either direction, flexing of said connecting member during movement of said damper blades compensating for irregularities in construction of the damper mechanism and preventing binding of said blades by said connecting member.

4. In a damper mechanism, in combination, a damper frame adapted to be positioned in a passage through which the ow of medium is to be controlled, a plurality of damper blades pivotally mounted in said frame and associated with each other in a manner to cooperate with each other in controlling the flow of medium, a bracket member attached to each damper blade, eachl in either direction, flexingl of said connecting member during movement of lsaid damper blades compensating for irregularities in construction of the damper mechanism and preventing binding of said blades by said connecting member.

lJOHN M. LARsoN.