Title:
DUCT FRAME OPENING
United States Patent 3815638
Abstract:
A duct opening frame, typically supplied in coil form, of flexible, bendable sheet material and adapted to be formed into a frame for attachment to low density, Fiberglas heating, ventilating and cooling ducts to provide means to receive grilles, registers and access doors on the duct.
US Patent References:
/1178114.html
Westlake - April 1916 - 1178114
Air duct
Bristol - September 1940 - 2215318
Predetermined bend line
Zalkind - November 1940 - 2221854
Method of making spurs
Grimland - August 1949 - 2479741
Furnace register frame
Deroo - September 1951 - 2566558
/1178114.html
Westlake - April 1916 - 1178114
Air duct
Bristol - September 1940 - 2215318
Predetermined bend line
Zalkind - November 1940 - 2221854
Method of making spurs
Grimland - August 1949 - 2479741
Furnace register frame
Deroo - September 1951 - 2566558
Application Number:
05/069163
Publication Date:
06/11/1974
Filing Date:
09/02/1970
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
454/331
International Classes:
F16L25/00; F16L53/00; F24F13/02; F24F13/06; F16L53/00
Field of Search:
29/190,183,193 285/424 98/114,101 165/50 138/103
US Patent References:
| 2916054 | Knockdown sectional air conduits | December 1959 | Callan | |
| 3001805 | Duct connector | September 1961 | Jones et al. | |
| 3340787 | Grille frames | September 1967 | Phillips | |
| 3347569 | Conduit connecting structure and method | October 1967 | Lindgren | |
| 3354947 | Air-conditioning system for a mobile home | November 1967 | McKinnon | |
| 3386434 | Method of and apparatus for installing a furnace | June 1968 | Castell et al. |
Primary Examiner:
Myracle, Jerry W.
Attorney, Agent or Firm:
Williamson, Bains & Moore
Parent Case Data:
This is a continuation of Ser. No. 642,634, filed May 11, 1967, now abandoned.
Claims:
What is claimed is
1. In combination with an elongate generally rectangular fiberglass duct having a continuous closed peripheral wall, a rectangular opening in the peripheral wall,
2. The combination as defined in claim 1 wherein the receiving element of each press clip is of substantially rectangular configuration and wherein the web elements of each press clip are of substantially rectangular shaped configuration.
1. In combination with an elongate generally rectangular fiberglass duct having a continuous closed peripheral wall, a rectangular opening in the peripheral wall,
2. The combination as defined in claim 1 wherein the receiving element of each press clip is of substantially rectangular configuration and wherein the web elements of each press clip are of substantially rectangular shaped configuration.
Description:
This invention relates to a duct opening frame for Fiberglas heating, ventilating and air conditioning ducts and, more particularly, relates to a duct opening frame of flexible, bendable sheet material typically supplied in coil form to be formed to order with conventional tools and by hand.
Although low density materials, such as Fiberglas, have been available and used for the past several years for heating, ventilating and air conditioning ducts, a suitable frame for attachment to the duct opening to provide means to receive registers, grilles and access doors thereon has not heretofore been available. My co-pending application, entitled METHOD AND APPARATUS FOR SUPPORTING AND RETAINING LOW DENSITY WEBS, Ser. No. 494,561, filed Oct. 11, 1965, now Pat. No. 3,712,649, discloses and claims supporting and joining apparatus for Fiberglas ducts providing a method and means to fabricate a continuous duct system from Fiberglas material. It has been found, however, that in addition to means for joining and retaining Fiberglas into a continuous duct system, a frame adapted to be attached to an opening in the duct to provide means to receive grilles, registers and access doors thereon has become necessary to the proper and efficient use of Fiberglas or other low density material in a duct system.
Heating, ventilating and air conditioning duct systems require openings therein along the system at predetermined intervals. The openings vary greatly in size, depending upon the size of the duct, the length of the run or the size of the room being serviced. Of course, other engineering design requirements affect the selection of the opening size. Consequently, frames must be available to reinforce the duct opening and to be mounted on the duct opening to receive grilles, registers and access doors. In the past, frames have been constructed at a factory or shop and shipped to a job site. A multitude of frames sizes must be manufactured and must be available at the job site. Prefabricated frames are expensive in that a wide variety of sizes must be made and stored by the manufacturer or contractor. Further, the prefabricated frame is difficult and time consuming to attach to an opening in the Fiberglas duct. Therefore, the contractor, the manufacturer or the contractor's supplier must maintain a large inventory of duct frames which have been prefabricated so that the contractor may meet the varying engineering requirements for the heating, ventilating and air conditioning duct systems.
With these comments in mind, it is to the elimination of these and other disadvantages to which the present invention is directed, along with the inclusion therein of other novel and desirable features.
An object of my invention is to provide a new and improved duct opening frame for attachment to Fiberglas ducts to provide means to assemble grilles, registers and access doors to the Fiberglas ducts, which duct opening frame is of simple and inexpensive construction and operation.
Another object of my invention is to provide a new and improved duct opening frame which may be supplied in coil form and formed to fit a predetermined opening at the job site with conventional tools and by hand.
Still another object of my invention is the provision of a duct opening frame which is shipped and stored in coil form thereby taking a minimum of storage or shipping volume yet which is manufactured from flexible, bendable sheet material which is easily fabricated on the job by conventional tools and by hand; and which sheet material includes slots along the bending lines to decrease bending resistance thereby allowing the operator to more conveniently bend the duct opening frame to snugly fit the Fiberglas duct without undue difficulty in performing the bends by hand.
A further object of my invention is the provision of a duct opening frame for attachment to Fiberglas ducts to provide means to receive grilles, registers and access doors directly thereon, which duct opening frame is extremely simple in its assembly and operation and will thereby permit quick and easy fabrication and attachment to Fiberglas ducts by a person of minimum skill and manual dexterity.
These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views, and in which:
FIG. 1 is a diagrammatic view of my duct opening frame as it appears in operation attached to a Fiberglas duct, with a grille mounted thereon and with portions of the components broken away for clarity;
FIG. 2 is a perspective view of my duct opening frame in coil form, shown prior to assembly;
FIG. 3 is a perspective view showing an initial step in the fabrication of my duct opening frame prior to assembly of the duct opening frame to a Fiberglas duct;
FIG. 4 is a perspective view of my duct opening frame as it would appear just prior to assembly to a Fiberglas duct;
FIG. 5 is a plan view of the novel press clip;
FIG. 6 is a perspective view of the novel press clip shown partially bent and prior to assembly to a Fiberglas duct;
FIG. 7 is a perspective view showing the alternate embodiment of my invention assembled to a Fiberglas duct showing a grille mounted thereon and with portions broken away for clarity; and
FIG. 8 is a perspective view of another embodiment of my invention shown in coil form.
In FIG. 1, a Fiberglas duct 10 is shown with a duct opening frame, indicated in general by numeral 11 mounted thereon. The duct opening frame is shown completely assembled with a grille 12 attached thereto by screws 13. The longitudinal duct opening is indicated by numeral 14 and the assembled duct opening frame 11 conforms to the opening in the duct in length and depth.
Referring now to FIG. 2, frame 11 is shown in roll or coil form, indicated by numeral 15. The roll comprises a plurality of duct engaging tabs 16 which are bendable along foldline or bendline 17. Longitudinal slots 18 are provided at predetermined intervals along foldline 17 to decrease the bending resistance of tabs 16 as they are bent or folded. The tabs are connected to web or collar 19. A grille or diffuser receiving element 20 is foldably attached to web 19 along foldline or bendline 21. Longitudinal slots 22 are provided along foldline 21 at predetermined intervals to decrease the bending resistance of receiving element 20 on web 19. Receiving element 20 includes a plurality of slotted apertures 23, transverse to foldlines 17 and 21 and spaced longitudinally along receiving element 20. Each receiving element actually constitutes an outturned flange.
Tab 16 may be provided with inwardly crimped terminal portions 24 crimped along foldline 25. These terminal portions may be omitted if desired.
Frame 11 is formed from the coil 15 by first notching receiving element 20 at predetermined intervals longitudinally along the receiving element as it is dispensed from coil 15. The notch is cut with conventional tools inwardly to foldline 21, and is indicated in FIG. 3 by numeral 26. Similarly, if necessary, a corresponding notch may be made in tabs 16 cut inwardly to foldline 17. (This notch is not shown herein). Notches 26 are cut in the receiving element at intervals corresponding to the length and depth of opening 14 in duct 10. The web is then bent at 90° along foldlines 27 to form frame 11. The web may be welded together, if desired. In this configuration, an upper lengthwise receiving element 20a and a corresponding lower lengthwise receiving element 20b is provided. Further, a pair of opposed receiving side elements 20c and 20d are provided. In like manner a plurality of upper lengthwise tabs 16a and corresponding lower lengthwise tabs 16b are provided. A pair of opposed side tabs 16c and tabs 16d are also provided. It should be noted that the inwardly crimped portions 24 of the tabs provides ease in inserting the rectangular frame 11 into duct opening 14.
Prior to insertion of the duct opening frame into the duct opening, the respective receiving elements 20a, 20b, 20c and 20d are folded outwardly at right angles to web 19. The frame, with tabs 16a, 16b, 16c and 16d projecting outwardly from the respective webs, may then be inserted into opening 14, as shown in FIG. 4. The outwardly projecting receiving elements abut duct 10 preventing further entry of the frame 11 into opening 14. At this point, web portions 19a, 19b, 19c and 19d, confront the portions of duct 10 which define opening 14 and are snugly abutted thereagainst. Duct engaging tabs 16a, 16b, 16c and 16d are folded into duct engaging relation by hand, sandwiching duct 10 between the tabs and the receiving elements thereby tightly securing frame 11 to duct 10 at opening 14. (See FIG. 1)
The duct opening frame is fabricated from 24 gauge galvanized sheet metal and is die cut to provide the tabs and receiving element therein. Slots 23 and 32 are one-eighth inch wide to receive a No. 8 sheet metal screw for mounting of grilles, registers, diffusers and the like thereto.
An alternate form of my invention is shown in FIG. 5. A press clip is indicated, in general by numeral 28 and includes a pair of duct engaging tabs or points 29 at each end thereof. A pair of webs 30 are connected to tabs 29. Receiving element 31 is connected to webs 30 therebetween and includes slotted apertures 32. Tabs 29 are bendable along foldlines 33 which include slots 34 therealong to decrease the bending resistance of tabs 29 relative to webs 30. Webs 30 are foldable relative to receiving element 31 along foldlines 35 which include slots 36 therealong to decrease the bending resistance. Press clip 28 is formed from 24 gauge galvanized sheet metal. Typically, the press clip is utilized to form a duct opening frame for ducts requiring mounting of a grille, diffuser, register and the like at transverse openings thereof.
In some instances, the press clips 28 will be utilized to mount and form a duct opening frame in one of the longitudinal walls of a duct rather than at the end of the duct as shown in FIG. 7. For example, it may be desirable to use the press clips 28 in the formation of a duct forming frame in the manner illustrated in FIG. 1. When the press clips are used in this fashion, the slots 32 in the press clip through which the screws pass will not be formed in the receiving element 31 but will be received in one of the webs 30. Specifically, the slots 32 will be formed in that web 30 which is presented outwardly. It is also pointed out that when the press clips are used to mount and form a frame such as the duct opening frame illustrated in FIG. 1, one of the web portions will preferably be longer than the other web portion.
A duct 10' is shown in FIG. 7 having transverse opening 14'. Press clips 28 are spaced along each side of the opening providing four clips denoted by numerals 28a, 28b, 28c and 28d. A grille 12' is shown mounted thereon with four screws 13' securing grille 12' to press clips 28 which are, in turn, securely mounted on duct 10'.
Another alternate form of my invention is shown in FIG. 8 which shows coil 15' having receiving element 20' with a plurality of circular openings 37. The openings are one-eighth inch in diameter to receive No. 8 sheet metal screws. Of course, press clip 28 may include circular openings rather than slotted openings 32 if desired. Coil 15' includes web 19' and tabs 16' bendably attached thereto.
In operation, the duct opening frame of my invention, when utilized to provide a frame for a longitudinal opening on a Fiberglas duct, is formed from coil 15. The frame size required is determined and a sufficient amount of material, corresponding to the perimeter of opening 14 in duct 10, is uncoiled and cut from the coil. The amount of material which is cut from the coil includes an extra half inch for overlapping. Next, conventional tinsnips are used to cut into the receiving element substantially normal to elongate web member 19, at intervals corresponding to the width and depth dimensions of duct opening 14 with notch 26 proceeding inwardly to foldline 21. If necessary, duct engaging tabs 16 may be similarly cut transverse to elongate web member 19, to foldline 17, if necessary.
The material may now be folded transversely at the web member along foldlines 27 to form a rectangular frame. As shown in FIG. 3, the frame is partially formed and is ready to be inserted into opening 14. First, receiving elements 20 are folded outwardly along foldlines 21 which are slotted at 22 to decrease the bending resistance. Frame 11 may now be inserted into opening 14 and is pushed into the opening until receiving elements 20 abut duct 10. The installer may now bend tabs 16 outwardly along foldline 17 sandwiching the duct between the receiving element and the duct engaging tabs.
The duct is now properly prepared to receive a register, diffuser, grille or access door. The unit may be attached directly to frame 11, utilizing slotted openings 23 in the receiving element. The slotted openings are one-eighth inch wide to receive a standard, No. 8 sheet metal screw.
In some instances, it is desirable to place a grille, diffuser, access door or register on a transverse, either circular or rectangular, opening in a duct system. This may be done by utilizing press clip 28 which is folded along foldlines 33 to provide duct engaging tabs 29 to engage duct 10', and then folded along foldlines 35 such that the edge of the duct 14' receives the receiving element 31 so that a unit may be secured thereon.
From the foregoing it will be seen that I have provided a new and novel duct opening frame for use with Fiberglas duct systems which is not only simple and efficient in construction and operation, but which is capable of being formed to fit varying size openings in ducts as may be necessary under design requirements. Further, the duct opening frame of my invention is provided with slots along foldlines to decrease the bending resistance such that all folds may be made by hand without the need for any tools whatsoever. This, therefore, greatly speeds up the assembly of my duct opening frame to Fiberglas ducts and results in considerable savings in labor costs to the contractor.
It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions without departing from the scope of my invention.
Although low density materials, such as Fiberglas, have been available and used for the past several years for heating, ventilating and air conditioning ducts, a suitable frame for attachment to the duct opening to provide means to receive registers, grilles and access doors thereon has not heretofore been available. My co-pending application, entitled METHOD AND APPARATUS FOR SUPPORTING AND RETAINING LOW DENSITY WEBS, Ser. No. 494,561, filed Oct. 11, 1965, now Pat. No. 3,712,649, discloses and claims supporting and joining apparatus for Fiberglas ducts providing a method and means to fabricate a continuous duct system from Fiberglas material. It has been found, however, that in addition to means for joining and retaining Fiberglas into a continuous duct system, a frame adapted to be attached to an opening in the duct to provide means to receive grilles, registers and access doors thereon has become necessary to the proper and efficient use of Fiberglas or other low density material in a duct system.
Heating, ventilating and air conditioning duct systems require openings therein along the system at predetermined intervals. The openings vary greatly in size, depending upon the size of the duct, the length of the run or the size of the room being serviced. Of course, other engineering design requirements affect the selection of the opening size. Consequently, frames must be available to reinforce the duct opening and to be mounted on the duct opening to receive grilles, registers and access doors. In the past, frames have been constructed at a factory or shop and shipped to a job site. A multitude of frames sizes must be manufactured and must be available at the job site. Prefabricated frames are expensive in that a wide variety of sizes must be made and stored by the manufacturer or contractor. Further, the prefabricated frame is difficult and time consuming to attach to an opening in the Fiberglas duct. Therefore, the contractor, the manufacturer or the contractor's supplier must maintain a large inventory of duct frames which have been prefabricated so that the contractor may meet the varying engineering requirements for the heating, ventilating and air conditioning duct systems.
With these comments in mind, it is to the elimination of these and other disadvantages to which the present invention is directed, along with the inclusion therein of other novel and desirable features.
An object of my invention is to provide a new and improved duct opening frame for attachment to Fiberglas ducts to provide means to assemble grilles, registers and access doors to the Fiberglas ducts, which duct opening frame is of simple and inexpensive construction and operation.
Another object of my invention is to provide a new and improved duct opening frame which may be supplied in coil form and formed to fit a predetermined opening at the job site with conventional tools and by hand.
Still another object of my invention is the provision of a duct opening frame which is shipped and stored in coil form thereby taking a minimum of storage or shipping volume yet which is manufactured from flexible, bendable sheet material which is easily fabricated on the job by conventional tools and by hand; and which sheet material includes slots along the bending lines to decrease bending resistance thereby allowing the operator to more conveniently bend the duct opening frame to snugly fit the Fiberglas duct without undue difficulty in performing the bends by hand.
A further object of my invention is the provision of a duct opening frame for attachment to Fiberglas ducts to provide means to receive grilles, registers and access doors directly thereon, which duct opening frame is extremely simple in its assembly and operation and will thereby permit quick and easy fabrication and attachment to Fiberglas ducts by a person of minimum skill and manual dexterity.
These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views, and in which:
FIG. 1 is a diagrammatic view of my duct opening frame as it appears in operation attached to a Fiberglas duct, with a grille mounted thereon and with portions of the components broken away for clarity;
FIG. 2 is a perspective view of my duct opening frame in coil form, shown prior to assembly;
FIG. 3 is a perspective view showing an initial step in the fabrication of my duct opening frame prior to assembly of the duct opening frame to a Fiberglas duct;
FIG. 4 is a perspective view of my duct opening frame as it would appear just prior to assembly to a Fiberglas duct;
FIG. 5 is a plan view of the novel press clip;
FIG. 6 is a perspective view of the novel press clip shown partially bent and prior to assembly to a Fiberglas duct;
FIG. 7 is a perspective view showing the alternate embodiment of my invention assembled to a Fiberglas duct showing a grille mounted thereon and with portions broken away for clarity; and
FIG. 8 is a perspective view of another embodiment of my invention shown in coil form.
In FIG. 1, a Fiberglas duct 10 is shown with a duct opening frame, indicated in general by numeral 11 mounted thereon. The duct opening frame is shown completely assembled with a grille 12 attached thereto by screws 13. The longitudinal duct opening is indicated by numeral 14 and the assembled duct opening frame 11 conforms to the opening in the duct in length and depth.
Referring now to FIG. 2, frame 11 is shown in roll or coil form, indicated by numeral 15. The roll comprises a plurality of duct engaging tabs 16 which are bendable along foldline or bendline 17. Longitudinal slots 18 are provided at predetermined intervals along foldline 17 to decrease the bending resistance of tabs 16 as they are bent or folded. The tabs are connected to web or collar 19. A grille or diffuser receiving element 20 is foldably attached to web 19 along foldline or bendline 21. Longitudinal slots 22 are provided along foldline 21 at predetermined intervals to decrease the bending resistance of receiving element 20 on web 19. Receiving element 20 includes a plurality of slotted apertures 23, transverse to foldlines 17 and 21 and spaced longitudinally along receiving element 20. Each receiving element actually constitutes an outturned flange.
Tab 16 may be provided with inwardly crimped terminal portions 24 crimped along foldline 25. These terminal portions may be omitted if desired.
Frame 11 is formed from the coil 15 by first notching receiving element 20 at predetermined intervals longitudinally along the receiving element as it is dispensed from coil 15. The notch is cut with conventional tools inwardly to foldline 21, and is indicated in FIG. 3 by numeral 26. Similarly, if necessary, a corresponding notch may be made in tabs 16 cut inwardly to foldline 17. (This notch is not shown herein). Notches 26 are cut in the receiving element at intervals corresponding to the length and depth of opening 14 in duct 10. The web is then bent at 90° along foldlines 27 to form frame 11. The web may be welded together, if desired. In this configuration, an upper lengthwise receiving element 20a and a corresponding lower lengthwise receiving element 20b is provided. Further, a pair of opposed receiving side elements 20c and 20d are provided. In like manner a plurality of upper lengthwise tabs 16a and corresponding lower lengthwise tabs 16b are provided. A pair of opposed side tabs 16c and tabs 16d are also provided. It should be noted that the inwardly crimped portions 24 of the tabs provides ease in inserting the rectangular frame 11 into duct opening 14.
Prior to insertion of the duct opening frame into the duct opening, the respective receiving elements 20a, 20b, 20c and 20d are folded outwardly at right angles to web 19. The frame, with tabs 16a, 16b, 16c and 16d projecting outwardly from the respective webs, may then be inserted into opening 14, as shown in FIG. 4. The outwardly projecting receiving elements abut duct 10 preventing further entry of the frame 11 into opening 14. At this point, web portions 19a, 19b, 19c and 19d, confront the portions of duct 10 which define opening 14 and are snugly abutted thereagainst. Duct engaging tabs 16a, 16b, 16c and 16d are folded into duct engaging relation by hand, sandwiching duct 10 between the tabs and the receiving elements thereby tightly securing frame 11 to duct 10 at opening 14. (See FIG. 1)
The duct opening frame is fabricated from 24 gauge galvanized sheet metal and is die cut to provide the tabs and receiving element therein. Slots 23 and 32 are one-eighth inch wide to receive a No. 8 sheet metal screw for mounting of grilles, registers, diffusers and the like thereto.
An alternate form of my invention is shown in FIG. 5. A press clip is indicated, in general by numeral 28 and includes a pair of duct engaging tabs or points 29 at each end thereof. A pair of webs 30 are connected to tabs 29. Receiving element 31 is connected to webs 30 therebetween and includes slotted apertures 32. Tabs 29 are bendable along foldlines 33 which include slots 34 therealong to decrease the bending resistance of tabs 29 relative to webs 30. Webs 30 are foldable relative to receiving element 31 along foldlines 35 which include slots 36 therealong to decrease the bending resistance. Press clip 28 is formed from 24 gauge galvanized sheet metal. Typically, the press clip is utilized to form a duct opening frame for ducts requiring mounting of a grille, diffuser, register and the like at transverse openings thereof.
In some instances, the press clips 28 will be utilized to mount and form a duct opening frame in one of the longitudinal walls of a duct rather than at the end of the duct as shown in FIG. 7. For example, it may be desirable to use the press clips 28 in the formation of a duct forming frame in the manner illustrated in FIG. 1. When the press clips are used in this fashion, the slots 32 in the press clip through which the screws pass will not be formed in the receiving element 31 but will be received in one of the webs 30. Specifically, the slots 32 will be formed in that web 30 which is presented outwardly. It is also pointed out that when the press clips are used to mount and form a frame such as the duct opening frame illustrated in FIG. 1, one of the web portions will preferably be longer than the other web portion.
A duct 10' is shown in FIG. 7 having transverse opening 14'. Press clips 28 are spaced along each side of the opening providing four clips denoted by numerals 28a, 28b, 28c and 28d. A grille 12' is shown mounted thereon with four screws 13' securing grille 12' to press clips 28 which are, in turn, securely mounted on duct 10'.
Another alternate form of my invention is shown in FIG. 8 which shows coil 15' having receiving element 20' with a plurality of circular openings 37. The openings are one-eighth inch in diameter to receive No. 8 sheet metal screws. Of course, press clip 28 may include circular openings rather than slotted openings 32 if desired. Coil 15' includes web 19' and tabs 16' bendably attached thereto.
In operation, the duct opening frame of my invention, when utilized to provide a frame for a longitudinal opening on a Fiberglas duct, is formed from coil 15. The frame size required is determined and a sufficient amount of material, corresponding to the perimeter of opening 14 in duct 10, is uncoiled and cut from the coil. The amount of material which is cut from the coil includes an extra half inch for overlapping. Next, conventional tinsnips are used to cut into the receiving element substantially normal to elongate web member 19, at intervals corresponding to the width and depth dimensions of duct opening 14 with notch 26 proceeding inwardly to foldline 21. If necessary, duct engaging tabs 16 may be similarly cut transverse to elongate web member 19, to foldline 17, if necessary.
The material may now be folded transversely at the web member along foldlines 27 to form a rectangular frame. As shown in FIG. 3, the frame is partially formed and is ready to be inserted into opening 14. First, receiving elements 20 are folded outwardly along foldlines 21 which are slotted at 22 to decrease the bending resistance. Frame 11 may now be inserted into opening 14 and is pushed into the opening until receiving elements 20 abut duct 10. The installer may now bend tabs 16 outwardly along foldline 17 sandwiching the duct between the receiving element and the duct engaging tabs.
The duct is now properly prepared to receive a register, diffuser, grille or access door. The unit may be attached directly to frame 11, utilizing slotted openings 23 in the receiving element. The slotted openings are one-eighth inch wide to receive a standard, No. 8 sheet metal screw.
In some instances, it is desirable to place a grille, diffuser, access door or register on a transverse, either circular or rectangular, opening in a duct system. This may be done by utilizing press clip 28 which is folded along foldlines 33 to provide duct engaging tabs 29 to engage duct 10', and then folded along foldlines 35 such that the edge of the duct 14' receives the receiving element 31 so that a unit may be secured thereon.
From the foregoing it will be seen that I have provided a new and novel duct opening frame for use with Fiberglas duct systems which is not only simple and efficient in construction and operation, but which is capable of being formed to fit varying size openings in ducts as may be necessary under design requirements. Further, the duct opening frame of my invention is provided with slots along foldlines to decrease the bending resistance such that all folds may be made by hand without the need for any tools whatsoever. This, therefore, greatly speeds up the assembly of my duct opening frame to Fiberglas ducts and results in considerable savings in labor costs to the contractor.
It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions without departing from the scope of my invention.