US 3796248 A
A folding blade type fire damper is provided with a thermally actuated resettable release link and retraction means co-operating with the link to reset the blades in their retracted condition upon actuation from outside the duct in which the damper is mounted.
Claims available in
Description (OCR text may contain errors)
United States Patent 1191 McCabe 1 Mar. 12, 1974 [5 REMOTELY RESETTABLE FIRE DAMPER 2,148,530 2/1939 Burke 126/2875 ux 3,665,996 5/1972 Roberts.. 160/1  Invent Franc f 3,687,185 8/1972 Singer 160/1 Box 181, Buckmgham, Pa. 18912  Filed: Aug. 28, 1972 Primary ExaminerMervin Stein [211 App! 28422l Assistant Examiner-Philip C. Kannan Related US. Application Data  Continuation-impart of Ser. No. 178,111, Sept. 7,
1971, Pat. No. 3,725,972. 7
 ABSTRACT  US. Cl 160/1, 160/35, 160/84  Int. Cl E05f 15/20 A folding blade type fire damper is provided with a  Field of Search 160/1, 84, 5, 6, 36, 35; thermally actuated resettable release link and retracl26/287.5, 285; 137/457, 79; 98/85, 86; tion means co-operating with the linkto reset the 1 251/66, 68 blades in their retracted condition upon actuation from outside the duct in which the damper is  References Cited mounted.
UNITED STATES PATENTS 3,646,877 3/1972 Ellis 160/84 X -12 Claims, 5 Drawing Figures CROSS REFERENCE TO APPLICATION DESCRIPTION OF THE PREFERRED EMBODIMENTS Although specific forms of the invention have been This application is a continuation-in-part of my prior selected for illustration in the drawings, and the followco-pending application for a Fire Link and Method of Actuating Same Ser. No. 178,] l l, filed Sept. 7, 1971, now US. Pat. Nos 3,725,972, and discloses and claims, in part, the subject matter disclosed and claimed therein.
BACKGROUND OF THE INVENTION This invention relates to thermally actuated fire dampers used in air ducts, and more particularly to a resettable link and a means co-operating therewith to reset the fire damper in its folded condition, from without the duct.
In the proir art, folding blade fire dampers such as those shown in my US. Pat. No. 3,273,632 and 3,401,734 were retained in a folded or retracted condition by a wire or chain held by a fusable link. The link was not resettable.
In my prior co-pending application I disclose a resettable link which can be actuated by a remote electrical signal to release the damper from its folded condition and allow it to extend to its fire blocking unfolded condition in the air duct in which it is mounted. However, in order to reset the damper in its retracted condition it is necessary to gain access to the air duct. It is desirable to be able to reset the damper remotely from outside the air duct. I
SUMMARY OF THE INVENTION associated with it for improved response to thermal conditions in theduct.
Accordingly, it is an object of my invention to improve'fire damper systems by providing a means for remotely opening and resetting dampers mounted in ducts.
This and other objects of my invention will become apparent from the following description of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an elevation of a remotely resettable folding blade fire damper in accordance with my invention shown partially in section, mounted in its environmental condition with alternate positions shown in phantom lines;
FIG. 2 is a partial plan view taken as indicated by the lines and arrows 2--2 in FIG. 1;
FIGv 3 is a section on a greatly enlarged scale taken as indicated by the lines and arrows 33 in FIG. 2;
FIG. 4 is a partial view similar to FIG. 3 showing the parts in an alternate position; and
FIG. 5 is a plan view taken as indicated by the lines and arrows 5-5 in FIG. 3.
ing description is drawn in specific terms for the purpose of describing there forms of the invention, this description is not intended to limit the scope of the invention which is defined in the appended claims.
A folding blade fire damper of the type disclosed in my patents referenced above is shown in FIG. 1 designated generally 10 in its environmental condition mounted in an air duct shown in phantom lines and designated generally 12. The damper comprises a frame 14 and a plurality of blades shown schematically and designated generally 16. The blades shown in full lines are in their folded or retracted condition. This is the condition in which they would normally be retained by a wire or chain and fusable link. In the prior art, when the link melted and separated, the blades unfolded and extended to the bottom of the frame as shown by the phantom lines at A. This wasthe unfolded or.fully extended condition in which they prevented air and fire from passing through the duct.
If it was desired to reset the damper, then it was necessary to gain access to the duct. One had to reach into the duct and raise the blades by hand to their folded condition B and then attach'another fusable link. By using a resettable link, the same link can be used again. By using the present invention, the damper can be reset from outside the duct. Among the advantages of this invention is that it provides a means for testing the functioning of the damper periodically at greatly reduced maintenance and test costs.
The damper reset comprises a pivotally mounted angled arm 18. The arm isv made of flat metal, preferably several inches wide to provide a stable surface upon which to rest the blades and to raise the blades without.
cocking them. This is accomplished as shown in phantom lines in FIG. 1 depicting several alternate positions. With the blades extended as at A a flexable braided wire 20 is loosely positioned as at C underneath the free end of the last blade. One end of the wire 20 passes through a hole in the free end of the arm 18 and is retained from being pulled through the hole by a metallic clip 22. The wire 20 passes over a pulley 24 which is fixedly attached to the upper extension 26 of the frame 10; the extension 26 being cantilevered from the top of the frame. The other end of the wire 20 extends through a hole 28 in the bottom of the frame 10 and a hole 30 in the duct, and terminates in a handle 32 attached thereto in any suitable manner.
The arm 18 is pivoted about a pin 36. Accordingly,
when the handle 32 is pulled from outside the duct, the wire 20 is drawn over the pulley 24 and begins to lift the blades 16. As more and more wire is withdrawn the blades are folded and raised upwardly and the arm 18 begins to engage the blades as shown at D. Upon further retraction, the arm fully pivots to the position shown in full lines wherein the end 38 FIG. 3 of the arm 18 mechanically interlocks with the pin 40 of the resettable link designated generally 42.
The link comprises a base 44 upon which are mounted a plurality of metal strips each insulated from the other and from the base. The outer strip 46 is a bimetallic thermally responsive element which when heated moves in the direction of the arrow E FIG. 4.
The rivet 48 retains the fixed end of the element 46 be- 52 slightly narrower than the end 58"(on the order of 0.030of an inch less) as this will direct the bending slightly forward to advantageously release the pin 40 from the hole-60. The pin 40 is cocked at its free end slightly back in a direction toward the rivet 48 in order to hold greater weight when engaged by the arm 38 as in FIG. 3. Accordingly, causing the greatest bending to occur closer to the free end of the element 46 upon heating of the element, provides for the release of more weight more efficiently.
The element 62 is a thin, flat strip of metal fixedly held at one end by the rivet 48 between the insulator spacers 64 and 50. The metal member 62 is preformed or bent so that its normal positionQwhen not acted upon by the member 46 would be that shown in part in FIG. 4. However, the member 46 is a heaviergauge material and in its normal-unheated condition it assumes the position shown in FIG. 3 wherein it forces the free end of element 62 back toward the base 44. The element 62 has sufficient spring resiliency in it so that it is not deformed by this action and will move to its normal position as shown in FIG. 4 when the element 46 has been sufficiently heated to bendit in the direction of the arrow E to the position shown in FIG. 4.
An electrical contact 63 is provided on the end of element 62 to engage an electrical contact '47 on element 46 and and complete the electrical circuit necessary to remotely heat element 46. When these contacts are separated as in FIG. 4 the circuit is broken and heating ceases. Thereafter, as element46 cools, itbegins to return to its normal condition as shown in FIG. 3. As long as the electrical signalis present when the contacts 43 and 47 again engage, the element 46 will again begin to heat up. The purpose of this is to .prevent overheating of the bimetallic element 46, which could cause 4 force of the member 46. It should be noted that the pin .40 is fixedly held on the end of the member 46, and is electrically insulated therefrom by the insulators 76.
To aid in guiding the pin into the hole60, the hole is made slightly o versized and the tabs 78 FIGS. 2 and 5 extending from the endof the end 38 are positioned closely adjacent to the walls 84 of the shroud 72. This provides an initial guide for the pin. In addition, the end 86 of the arm end 38 fits closely within the walls of the shroud thereby providing a further guide.
It will be apparent from what has been disclosed that various changes may be made by those skilled in the art within the principle and 'scopeof the invention. For example, the cable 20 could be remotely controlled.
It should be noted that when the cable is retracted in the duct, it provides a visible indicator outside the duct that the damper blades have fallen.
It will further be understood that the Abstract of the Disclosure set forth above is intended to provide a non-legal technical statement of the contents of the disclosure in compliance with the Rules of Practice of the United States Patent Office, and is not intended to limit the scope of the invention described and claimed herein.
What is claimed is:
1. In combination with a folding blade damper having I blades movable between a folded and unfolded condition, the improvement comprising: a resettable link thermally actuatable between a closed and opened condition, comprising a bimetallic element cantilevered from a support connected to said damper and having a narrow neck portion intermediate the free end and the supported end, which element is thermally responsive to open and close said link; and a retraction means connected to said damper cooperating with said link to move said blades from their unfolded to their folded condition and retain them in their folded condition upon actuation from outside said damper.
2. The invention of claim 1 wherein said link has a pin extending from the free end of said element toward elastic deformation or burning up of the electric circuit components.
The base 44 is fixedly attached as by. riveting to an agnled bracket 70 which is fixedly attached by any suitable means to the overhang 26. The angled bracket is a solid piece of metal. Mounted about the bracket and link 42 is a solid metallic shroud 72. The shroud can be fixedly or pivotally attached to the angled bracket 70.
As shown, it provides an enclosure about the link 42 open only at the lower end designated generally 74 FIG. 3. This prevents heat dissipation which would result from air flowing through the duct attoo fast a rate. The open end would allow entry of hot air for thermal actuation; while preventing air flow through.
To aid in the mechanical interlocking of the end 38 with the pin 40, l have provided a sloping surface 80 on the pin 40 which is engaged by the sloping surface 82 of the advancing end 38 of the arm. As the wire 20 is drawn through the device the advancing end 38 cams the pin 40 outwardly from its normal position in FIG. 3 until the hole 60 is aligned with the pin 40 and the. pin
drops into place as shown in FIG. 3 under the springsaid support for engaging said retraction means.
3. The invention of claim 2 wherein said neck is narrower at the end thereof most remote from'saidsupport.
4. In combination with a folding blade damper having blades movable between a folded and unfolded condition, the improvement comprising: a resettable link connected to said damper; and a retraction means com- .prising an arm pivotally connected to said damper; said arm adapted to mechanically interlock with said link when said blades are in a folded condition and retain them in their folded condition; and a flexible member connected to the free end of said arm and coacting with said damper to pivot said arm and fold said blades upon retraction from outside saiddamper.
5. The invention of claim 4 wherein in the unfolded condition said arm is disposed on one side of said blades and said flexible member passes about the free end of one of said blades.
6. The invention of claim 4 wherein said damper has a frame'and said flexible member extends beyond said frame in both the folded and unfolded condition.
7.-The invention of claim 2 wherein said link comprises a bimetallic element having a pin extending from one end presenting a beveled surface to the free end of said arm.
8. The invention of claim 4.wherein said arm has a guide means at its free end to guide it into engagement with said link.
9. In combination with a folding blade damper having blades movable between a folded and unfolded condition, the improvement comprising: a resettable link connected to said damper; and a retraction means connected to said damper cooperating with said link to move said blades from their unfolded to their folded condition and retain them in their folded condition upon actuation from outside said damper; said link comprising a bimetallic element cantilevered from a support thermally actuatable between a closed and opened condition of engagement and disengagement with said retraction means; and a second element cantilevered from said support; said elements being electrically insulated from each other and from said support; said elements comprising an electric switch.
10. The invention of claim 9 wherein said second element is resilient and is movable between a flexed position in engagement with said bimetallic element and an upon actuation from outside said damper; said resettable link comprising a bimetallic element cantilevered from a support and having engagement means at the free end thereof for engaging said retraction means; said bimetallic element being thermally actuatable between a closed and opened condition of engagement and disengagement with said retraction means and being substantially closed by a shroud.