US3017694A - Metal bending method and product - Google Patents

Description

Jan. 23, 1962 M. GOLDSMITH METAL BENDING METHOD AND PRODUCT 4 Sheets-Sheet 1 Filed Jan. 10, 1958 BY iw Y lim v Jan. 23TW62 M. GOLDSMITH METAL BENDING METHOD AND PRODUCT 4 Sheets-Sheet 2 Filed Jan. 10, 1958 INVENTOR M1113 aldsmz'i ATTORNEYS Jan. 23, 1962 M. GOLDSMITH METAL BENDING METHOD AND PRODUCT 4 Sheets-Sheet 3 Filed Jan. 10, 1958 INVENTOR M01913 Galdamiffi ATTORNEY/5' Jan. 23, 1962 M. GOLDSMITH METAL BENDING METHOD AND PRODUCT 4 Sheets-Sheet 4 Filed Jan. 10, 1958 A TTORNEYS tes Pate The present invention relates to the production of a flexible connector stock material in which one side marginal portion of two elongated metal strips are secured to opposite side margins of an elongated flexible strip, e.g., a fabric strip.

The invention more particularly relates to the production of flexible connector stock material as aforesaid in which the combined widths of the metal strips do not substantially differ from the width of the fabric strip.

The present invention is a continuation in part of my prior copending application, Serial Number 402,096, filed January 4, 1954, and issued March 4, 1958 as Patent 2,825,384.

In my prior copending application, each marginal side edge of an elongated strip of fabric is securely attached to a separate elongated strip of metal by progressively longitudinally advancing the two metal strips along parallel paths in predetermined widthwise relationship. The strip of fabric is placed upon the metal strips and bending pressure is progressively applied to the outer marginal portion of each of the metal strips to bend the outer marginal portions of these metal strips over upon the strip of fabric. Pressure is then progressively applied to securely attach a marginal portion of each of said metal strips to each of the side edges of the strip of fabric and the secured together stock material is then coiled simultaneously with the aforesaid progressive securement.

In accordance with a feature of my said copending application, the metal strips overlap and this permits the production of a flexible connector stock material in which the fabric strip is of minimum width, thus effecting substantial savings in the cost of the product which is produced.

In some heating and ventilating installations, a wider fabric strip is insisted upon and in such instance the desired product may be produced as taught in my prior copending application. However, the need for overlapped metal strips is eliminated when the fabric width required or specified by the purchaser is as great or greater than the combined widths of the two metal strips which is required to enable the flexible connector stock material to be suitably secured, as is conventional, in a heating and ventilating duct system.

When flexible connector stock material is produced in accordance with the procedure of my prior copending application using two metal strips, various problems arise which will be more fully described hereinafter and which are overcome to a very considerable extent in my prior application. The present invention represents an improvement over my prior application in which the apparatus is considerably simplified and in which certain problems incident to proceeding with two metal strips are entirely avoided.

More particularly, when proceeding with two metal strips, it is essential to precisely control the longitudinal relative movement of each of the metal strips with respect to one another. Further, only a single edge of each of the meal strips is deformed incident to bending securement of the metal strips to the fabric strip and this leads to a serious problem of bowing which results from the stretching of one side marginal portion of a metal strip without a corresponding deformation of the opposite marginal portion. Also, the guiding of each of the metal ice strips with respect to its lateral position presents a problem requiring the utilization of guiding means disposed between the bending means for the purpose of laterally confining the inner edges of the two metal strips which are present.

The present invention entirely avoids the above referred to difficulties by employing a single metal strip which is severed after securement to opposite marginal portions of the elongated fabric to provide a flexible stock material of the same type and character as described in my prior copending application with the single exception that the fabric strip is not narrower than the combined widths of the metal strips.

More particularly, the present invention provides automatic precise longitudinal relative movement, automatic avoidance of bowing and the elimination of internal guides for the metal strips.

In accordance with the present invention, an elongated fabric strip is superimposed upon a single, preferably slightly wider metal strip and both of the side marginal portions of the metal strip are bent over into secure engagement with the-adjacent side marginal portions of the fabric strip. The metal strip is then longitudinally severed between its side marginal portion (the line of severing is preferably straight and it may be centrally positioned or positioned slightly to the side of center) to thereby provide a completed flexible connector stock material in which two elongated metal strips are secured to opposite side marginal portions of a single fabric strip.

The severing operation may be conducted immediately after securement or later, prior to use of the stock material in the construction of a flexible connection in a duct system. When the severing operation is performed immediately, the product may be coiled immediately in lengths of from 25 to feet or longer, and it may be dispensed from the coil as desired ina form which is available for immediate use.

In another preferred form of the invention, the metal strip is longitudinally scored, preferably prior to securement to the fabric strip and the completed product including the scored metal strip broken apart, as by flexing of the scored metal strip immediately prior to use. The product containing a single scored metal strip may also be coiled to facilitate shipment and storage prior to use and severed from the coil in desired lengths while still in the form of a single scored metal strip secured to a single fabric strip. The severed length of this product may then be flexed by the sheet metal worker about the score line to quickly provide the flexible connector piece having two separate metal strips which it is desired to employ.

The invention includes the method of producing the flexible connector stock material starting with a single strip of metal to produce the final flexible connector stock material including separate metal strips as well as the method of producing a flexible connector stock material blank which is scored to enable severing thereof in simple and efiicient manner by the user. The invention also includes the flexible connector stock material blank itself having a longitudinally scored single metal strip.

The invention will now be more fully described, reference being had to the accompanying drawings in which:

FIG. 1 is a side elevational view of an illustrative machine constructed in accordance with the present invention;

FIG. 2 is a fragmentary plan view with the fabric guide in section;

FIG. 3 is a sectional view taken on the line 3-3 of FIG. 2;

FIG. 4 is a fragmentary vertical sectional view taken on an enlarged scale and showing illustratively severing means for longitudinally severing the metal strip while leaving the fabric strip intact;

FIG. 5 is a cross-section showing the superimposed 3 fabric strip and metal strip with the side marginal portions in partially bent over position;

FIG. 6 is a view similar to FIG. and showing a modified form of the invention in which the single metal strip is provided with a longitudinal deep channel permitting severing of the metal strip by flexure thereof after securement of the metal strip to the fabric strip has been completed;

FIG. 7 is a partial perspective View of the product produced in accordance with the modification shown in FIG. 6 and illustrating the manner in which the metal strip is flexed to separate the metal strip into a pair of strips to thereby produce a flexible connector stock material from a scored or deeply channeled blank;

FIG. 8 is a top plan view of a fabric guide adapted to laterally fold a strip of fabric passing therethrough so that the fabric strip deposited upon the single metal strip may be wider than the strip of metal although the lateral fold produces an effective width of fabric strip of appropriate size for deposition and subsequent securement to the side marginal portions of the metal strip;

FIG. 9 is a cross-section taken on the line 99 of FIG. 8;

FIG. 10 is a view similar to FIGS. 5 and 6 and illustrates the final securement operation performed in the situation in which the fabric strip is folded over in the manner indicated in FIG. 8; and

FIG. 11 is a perspective view of the product produced in FIG. 10 with the fabric strip unfolded to facilitate severing of the metal strip along the length thereof.

Referring to FIG. 1 of the drawing, a single elongated strip of metal 10 is continuously withdrawn from a supply coil (not shown) and pulled into and through two juxtaposed laterally spaced parallel series of forming rolls indicated generally by the numeral 20. The forming rolls are driven by means of motor 11, belt 18, and pulley 19. A single strip of fabric is fed from a supply (not shown) and slid along an overhead chute 31 to a fabric guide 32 supported by uprights 34. A weight 33, secured to the chute 31, as shown, is placed upon the fabric 30 and serves, together with the friction of the fabric against the chute itself, to provide suitable tension to the fabric which is supplied. The fabric 30 passes under idler roll 35 which presses the fabric 30 against the surface of the fabric guide 32, thus additionally reducing the danger of having the fabric wrinkle.

It will be understood that the specific means of supplying the fabric 30' which has been illustrated is not essential to the invention. Thus, fabric 30 may be superimposed upon the metal strip 10 in advance of the forming rolls 20 and travel through the entire length of the forming rolls 20 together with the metal strip 10.

The metal strip 10 together with the superimposed fabric 30 emerge from the forming rolls 20 and are permanently secured together by pressure crimping rolls indicated generally at The use of crimping rolls provides enhanced securement between the fabric and the metal whereby a greater resistance to separation is achieved. As will be appreciated, the pressure crimping rolls 40 may be omitted and smooth surfaced pressure rolls employed or such smooth pressure rolls may be employed in addition to the crimping rolls. The crimps are preferably pointed but they may simply depress lines into the bent over portion of metal.

The product which is continuously produced is preferably advanced beneath roller 50, contact of the roller with the product serving to rotate said roll which actuates a counting device 51 to indicate the length of product produced by operation of themachine.

In the form of the invention shown in FIG. 1, cutting means 96 (which is preferably constituted by a circular saw) driven by motor M via pulley 92 and belt 93 is employed to continuously sever the single metal strip to thereby produce a flexible connector stock material comprising two elongated strips of metal each having a side marginal portion bent into securement With an opposite side marginal portion of a single fabric strip.

The product, as continuously produced, is fastened to a coiling reel indicated generally at 70 by leading the secured strips of metal and fabric over one of the bars 71 and under the next succeeding bar whereby the advancing product is secured to the coiling reel by means of the natural resiliency of the metal strips.

As will be appreciated, coiling reel 70 may be dispensed with and the product produced in the form of flat strips which are cut to desired length. Further, other means may be employed to secure the flexible connector stock material product to the coiling reel. In the form illustrated, the strip of fabric 30 is on the outside of the coil. Obviously, the coil 70 may be differently positioned and oppositely rotated so that the metal strip is on the outside of the coil. The reel 70 is preferably only a few feet, e.g., 3-10 feet from the crimping rolls 41.

The coiling reel 70 is preferably driven at a velocity which at least matches the linear rate of travel of the flexible connector stock material which is produced. In the form of the invention illustrated, coiling reel 70 is driven by motor 72, power from the motor being transferred to the coiling reel 70 by means of a reduction gear 73, belt 74, variable speed reducing devices 75 and belt 76. The belt 76 is preferably connected to a section of the variable speed reducing device 75 having a diameter of proper size to cause the bars 71 on the coiling reel 70 to advance at the same, or slightly greater, linear velocity than the product which emerges from the machine. If a slightly greater velocity is employed, slippage of belts 74 and 76 will occur and provide a constant torque to the coiling reel 70. This constant torque is not detrimental.

After the desired length of product has been produced and coiled on the coiling reel 70, the product is severed by cutting device 80, and slid off the bars 71 on the coiling reel 70 to provide a coil which may be packaged in this form in any suitable container.

To illustrate suitable operation, motor 11 drives the forming rolls 20 at a rate suflicient to produce about 20 feet of product per minute. Accordingly, motor 72 is operated at 1,750 rpm, a reduction gear ratio of 80 to 1 is employed and the variable speed reducing device is set to produce a 3 to 1 reduction in belt velocity to thereby provide bars 71, which move in a circle of 30 inch diameter, with a velocity which coincides with the rate of travel of the flexible connector stock material which is produced.

While the above illustrates a practicable manner of operating the machine of the invention, it will be understood that production rates may be considerably more rapid, particularly since in the present invention there is no need to precisely regulate the rate of travel of the two independent metal strips.

While a suitable coiling diameter is 30 inches, a smaller diameter may be employed. When resort is had to coiling diameters substantially smaller than 30 inches, e.g., from 10l5 inches in diameter, the metal strip in coiled form is slightly distorted so that it cannot be removed from the coil in fiat condition. In some instances, a small arc in the flexible connector stock material which is withdrawn from the coil may be tolerated. Preferably, the coil diameter is sufficiently great to produce a substantially flat length of product upon removal thereof from the coil. There is, of course, a practical limit to the diameter which can be employed since larger coils of excessive diameter (above about 40 inches) are unwieldly to handle, ship and store.

Motors 11 and 72 are preferably supplied with electric current from a common circuit so that both may be actuated and stopped simultaneously with a common switch. If desired, the counting device 51 may be connected with an electrical relay which breaks the electric circuit to the motors 11 and 72 so that the machine may be automatically stopped when the desired length of product has been produced.

As is evident from FIG. 1, the juxtaposed laterally spaced parallel series of forming rolls 20, pressure crimping rolls 4t counting device 51 and cutting device 80 are all mounted upon table 81. The table 81, as can be seen in FIGS. 1 and 2 has apertures 82, 83 and 84 to receive the forming rolls 20, the pressure crimping rolls 40, and the severing means 90 respectively.

The opposite side marginal portions of the metal strip are acted upon by the forming rolls 21-25 and 21'25 and these forming rolls function to bend the opposite side marginal portions of the metal strip 10 in a stepby-step fashion upwardly over upon the side marginal portions of the single strip of fabric 30. As the metal strip is advanced through the machine the bending of the metal is progressive along the length of the metal strip 10.

The metal strip 10 is preferably guided at its outer side edges on its way to the forming rolls 20 by guide rolls 12.

In the preferred form of the invention, as can be seen in FIGS. 2 and 3, the fabric guide 32 extends from above to a position between the forming rolls 23 and 24. The fabric 30 slides over the convex surfaces of the guide 32 and is thereby introduced into the nip between the form rolls '24, 24'. The fabric guide 32 terminates in a presser tongue 36 which is positioned between the laterally spaced forming rolls and extends beyond the forming rolls 24. This tongue 36 serves to hold the fabric in place and additionally functions, together with the curvature of the fabric guide 32, to properly position the fabric 34) in unwrinkled condition upon the metal strip 18. The fabric guide 32 is curved, both along its length and along its width. The curvature of the fabric guide 32 serves to prevent wrinkling of the fabric 30.

Preferably, fabric 38 is provided with a sewn beaded edge portion at each of its longitudinal side marginal edges. The presence of the beaded edge portions of the fabric 38 serve to provide enhanced securement to the bent over side marginal portions of the metal strip 14 The presence of the bead also serves, together with the lateral curvature of the fabric guide 32 to prevent the fabric 31 from being displaced to either side on the fabric guide 32. Preferably, the fabric guide 32 is tapered along its entire length from an enlarged entrance end to an exit end of the same width as the space between the upstanding edges of the metal strip 18 in order to compensate for variations in the width of the fabric 30. The sewn bead on the fabric strip is identified by the numeral 26.

The product emerging from forming rolls 25, 25 advances between pressure crimping rolls 41, 41' which function to permanently secure the metal strip 10 to the side marginal portions of the fabric 30. It is not necessary to positively drive the crimping rolls 41, 41. Instead, these crimping rolls may be rotated by passage of the preliminarily secured together product therebetween.

In order to insure that the bending roll on each side of the machine will operate at the same speed, it is preferred to mount these rolls upon a common shaft as is illustrated in FIG. 2.

The forming action of each series of forming rolls upon a single edge of the metal strip 10 serves to stretch this edge. Since both side marginal portions or edges of the metal strip 10 are equally stretched, the stretching forces are distributed uniformly across the width of the metal strip, thus eliminating any tendency of the metal strip to bow (curve sidewardly).

The common shafts upon which the forming rolls are mounted are journalled in side plate 98 and extend through side plate 99. Each of the side plates 98 and 99 are supported by table 81 and are each divided into an upper and lower side plate, respectively, which support the upper rollers 21-25 and the lower rollers 21'-25', respectively. The upper and lower sections of the side plates 98 and 99 are fixed in position by bolts 100 and 6 101 and secured by locking nuts 102 and 103, as can best be seen in FIG. 3. The material passing between the forming rolls serves to maintain the upper and lower sections of the side plates 98 and 99 in spaced relation and the locking nuts 102 and 103 serve to define the maximum permissible spacing, and, accordingly, the pressure imposed upon the material by the forming rolls. Since the forming rolls 24, '24 and 25, 25 have to contend with the additional thickness imparted by the fabrics 30, the

upper and lower side plates must be maintained closer together at their left end (as viewed in FIG. 3) by the locking nut 102 to prevent an undue portion of strain being placed on forming rolls 24, 24. Adjustment of the pressure of the various forming rolls 21-25 with rolls 2125 may be effected in various manners forming no part of the invention.

The transfer of power from the motor 11 to the various forming rolls 2125 and 2125 is more specifically described in my above mentioned Patent 2,825,384.

The present invention is limited with respect to the minimum width of fabric strip which may be employed although wider fabric strips may be employed by longitudinally folding the fabric so that the center portion thereof is folded over while the side marginal portions project toward the side margins of the metal strip for securement when these side margins are bent over into engagement with the fabric strip. Thus, the free width of the fabric extending laterally between the folded over portions of metal is at least equal to the combined widths of the metal strips from the bent side margins to the inner free sides thereof less the distance of the bent over portions of the metal strips. This description defines the minimum fabric width which may be produced in a flexible connector stock material in accordance with the invention and, as explained above, the fabric strip may be wider than this minimum. For the production of fabric strips of smaller width it is necessary to resort to the use of separate metal strips in accordance with the teachings of my above mentioned Patent 2,825,384.

In accordance with the present invention, the single strip of metal 10, after it has been secured to the single strip of fabric '30, and preferably after final securement as by the pressure crimping rolls 41, is acted upon by the severing means in order to longitudinally divide the metal strip 18 into a pair of metal strips each of which is secured to an opposite marginal portion of the single strip of fabric 30.

In FIGS. 2 and 3, a circular saw 98 is employed to continuously slit the metal strip 10 as it advances through the machine. In order to prevent severing of the fabric strip 38, the circular saw 90 is overlaid by a shield 94 which functions to slightly raise the fabric strip 30 and preferably to also slightly depress the metal strip 11) whereby the metal strip is continuously severed without damage to the fabric strip 30.

The shield 94 is supported at its trailing end by an up standing knife-like support 95 which is, in turn, supported by a strap 96 which is secured, as by securing means 97 to the supporting table 81. The action of the circular saw 90, the shield 94 and knife support 95 will be more clearly seen in FIG. 4 where it will be observed that the knife support 95 extends upwardly through the slitted metal strip 10 (the slit being identified by the numeral 13) and the shield 94 is shown as extending over the upper edge of the circular saw 90 to a point in advance of the point of engagement of the saw with the metal strip 10 where it preferably bears downwardly upon the upper surface of the metal strip 10. The bearing point is indicated by the numeral 97A.

The product in an intermediate stage of production is shown in FIG. 5 which pictures the forming rolls 24 and 24' and also the superimposed metal strip 10 and fabric fabric strip 30. The beaded portion 26 of the fabric strip 3-0 may also be seen.

As will be understood, when the side marginal portions 14 of the metal strip have been forced downwardly into secure engagement overlapping the beaded portion 26 of the fabric strip 39, there will be continu ously formed a product which, after severing along the length of the metal strip 10, will constitute a flexible connector stock material which, after transversely severing the material to desired length, opening the metal strips outwardly, and bending to produce a portion of a duct (as is conventional) will serve to provide a vibration reducing connection in duct work; as is more fully explained in my above mentioned Patent 2,825,384.

In FIG. 6 there is disclosed a modified form of the invention which permits the severing operation accomplished by the circular saw 90 to be eliminated. In this form of the invention, the metal strip 10, preferably prior to passage through the machine, is deeply scored or deeply channelled as is indicated by the numeral 15. In this form of the invention, the product containing the longitudinal centrally disposed deep channel may be continuously produced and coiled without separation of the metal strip 10 into two separate strips as is normally necessary for the production of a flexible connector stock material. This unsevered material may be withdrawn when desired from a coil thereof and transversely severed to produce a desired length thereof at which point, the severed length of flexible connector blank may be flexed along its length, as is illustrated in FIG. 7, the flexing being preferably a back and forth flexing as is indicated by the double-ended arrows 16. In this manner, the metal strip 10 is separated to produce two separate metal strips 10A and 10B when the metal strip 10 is broken along the channel 15.

FIG. 8 illustrates a modification of the invention in which the fabric strip which is deposited upon the metal strip 10 is laterally folded as indicated by the numeral 110 whereby a fabric strip which is wider than the metal strip may be caused to possess an effective width which is smaller than the metal strip and which is therefore adapted to be deposited upon the metal strip in a manner permitting the marginal portions of the metal strip to be bent over upon the side margins of the fabric strip.

As can be seen in FIG. 8, the wide fabric strip 30 is longitudinally advanced in the direction indicated by arrow 111 through a folding guide 112. The folding guide 112 comprises a base portion 113 which tapers inwardly from the entrance to the exit end of the folding guide and a pair of fabric folding flaps 114 and 115, respectively. As will be apparent from FIGS. 8 and 9, the fabric strip 30 is superimposed upon the upper surface of the flap 114 and is passed under the flap 115. Accordingly, as the fabric 30' is pulled through the folding guide 112, the fabric is folded by the free inner ends of the flaps 114- and 115 to produce the fold 110.

The folding action will be apparent from the drawings the phantom lines being employed to illustrate portions of the flap 114- which underlie the fabric 38 but which overlie the flap 115. The flaps 114 and 115 are illustrated in FIG. 9 as being crimped at 116 to effect releasable securement to the upstanding marginal flanges of the base 113. While this structure is preferred, it is not essential and the flaps 114 and 1.15 may be integral with the base portion 113.

FIG. 10 illustrates the folded over fabric 30" deposited on the metal strip 10 with the bent over portions 14 of the metal strip being subjected to final securement between crimping rolls 41 and 41. As will be apparent, the fabric strip 30' containing the lateral fold 110 is effectively identical with the fabric strip 30 illustrated in FIGS. 5 and 6 despite the increased lateral width thereof. This increased lateral width facilitates subsequent longitudinal severing of the metal strip 10 as is illustrated in the perspective showing of FIG. 11. As will be apparent, the fabric strip 30' has been unfolded to remove the fold 110 and thereby provide clearance between the fabric strip 30' and the metal strip 10' to permit the insertion therebetween of severing means, such as the ships or metal shears 120 which is diagrammatically illustrated.

It will be understood that the invention has been only illustratively set forth, thus, additional bending rolls may be interposed between the bending rolls Z5 and the pressure crimping rolls 41 to produce a more secure bending contact between the bent over marginal portion 14 of the metal strip 10 and the beaded portion 26 of the fabric strip 30 prior to crimping as by the rollers 41. A single fold securement is illustrated which is crimped at spaced points 17 and this type of securement is preferred. A plurality of folds instead of a single fold may be employed but is less preferred because the securement is less effective and because it is more difficult for the sheet metal worker to cut through the double fold.

Further, the forming rolls of the invention have been shown as being laterally juxtaposed to provide a simultaneous and substantially equal bending action upon each side of the metal strip 10. While this lateral juxtapositioning is preferred, it is not essential and the bending rolls may be spaced at different points along the length of the metal strip 10.

The severing means in the form of the invention which has been illustrated is a circular saw. Various continuous slitting devices may be employed instead of the circular saw illustrated and the invention is not intended to be limited to the specific cutting means which have been illustrated.

The term fabric as employed herein is intended to include any flexible, yieldable sheet material, as for example canvas, woven asbestos webbing or listing tape, sheets of rubber and synthetic resinous materials such as Neoprene vinyl polymers and copolymers and woven and unwoven fabrics coated with rubber or synthetic resinous materials. Some of these flexible yieldable sheet materials cannot be satisfactorily sewn, in which case a thickened margin may be employed in place of a sewn marginal bead.

Other and further changes will be immediately apparent to those skilled in the art, the invention being defined in the claims which follow.

I claim:

1. A method of continuously producing flexible duct connector material having two elongated metal strips each having a side marginal portion bent into securement with an opposite side margin of a fabric strip in which the free width of the fabric strip is at least equal to the combined widths of the metal strips that may be positioned within the opposite side boundaries of said free width comprising: longitudinally advancing a single elongated strip of metal; placing an elongated strip of fabric on said strip of metal; roll forming the metal strip to progressively bend over the side marginal portions of said metal strip upon the side margins of said fabric strip to secure the side margins of said fabric strip to the side margins of said metal strip whereby the opposite side margins of said fabric strip are secured to said metal strip, the free width of fabric is in non-adhesive contact with and at least equal to the combined widths of the metal strip within the opposite side boundaries of said free width, and said metal strip is substantially uniformly distorted across its width by said bending thereof; and cutting said metal strip in a line along the length thereof between the sides of both the fabric and metal strip to form two separate metal strips.

2. A method as recited in claim 1 in which said secured together strips are coiled after cutting of said metal strip, and said bending, cutting and coiling steps occur successively in a continuous operation.

3. In the continuous production of flexible duct connector material comprising: providing a single elongated metal strip, weakening said metal strip between its sides in a longitudinal line enabling breaking of said metal strip along said line upon transverse flexure of the strip; longitudinally advancing said single strip of metal; placing an elongated strip of fabric on said strip of metal; roll forming the metal strip to progressively bend over the side marginal portions of said metal strip to secure the side margins of said fabric strip to the side margins of said metal strip whereby the opposite side margins of said fabric strip are secured to said metal strip, the free width of fabric is in non-adhesive contact with and at least equal to the width of the weakened metal strip within the opposite side boundaries of said free Width, and said metal strip is substantially uniformly distorted across its width by said bending thereof.

4. The method of claim 3 wherein the secured together strips are coiled, and the bending of the metal strip and coiling of the connector material occur successively in a continuous operation.

5. The continuous production of flexible duct connector material comprising: longitudinally advancing a single elongated strip of metal; placing an elongated strip of fabric upon said metal strip; roll forming the metal strip to progressively bend over the side marginal portions of said metal strip to secure the side margins of said fabric strip to the side margins of said metal strip whereby the opposite side margins of said fabric strip are secured to said metal strip, the free width of fabric is in non-adhesive contact with and at least equal to the Width of the metal strip within the opposite side boundaries of said free width, and said metal strip is substantially uniformly distorted across its width by said bending thereof; and after said fabric is placed upon the strip of metal, weakening said metal strip between its sides in a longitudinal line enabling breaking of said metal strip along said line by transverse flexure of the metal strip.

6. The method of claim 5 wherein the secured together material is coiled.

7. A method of continuously producing flexible duct connector material comprising: longitudinally advancing a strip of metal weakening said metal strip between its sides in a longitudinal line enabling breaking of said metal strip along said line by the transverse fiexure of the metal strip; placing an elongated, longitudinally extending folded strip of fabric on said metal strip; and roll forming the side marginal edge portions of the metal strip to progressively bend said edge portions over and upon the side margins of said fabric strip to secure the side margins of said fabric strip to the side marginal portions of said metal strip, whereby said fabric strip is secured to said metal strip, the free width of fabric is in non-adhesive contact with and greater than the width of the metal strip Within the opposite side boundaries of said free width, and said metal strip is uniformly distorted across its Width by said bending thereof.

8. The method of claim 7 wherein the secured together material is coiled.

9. Flexible connector duct blank adapted upon flexure to provide flexible connector duct material having two elongated metal strips each having a side marginal portion bent into securement with an opposite side margin of fabric strip, said blank comprising: a single metal strip which is weakened between its sides in a longitudinal line enabling breaking of said metal strip along said line of weakness upon transverse flexure of the metal strip, the side marginal portions of said metal strip being bent over, a strip of fabric non-adhesively superimposed upon said metal strip between the bent over marginal portions of said metal strip, said marginal portions of the metal strip being bent into engagement with the side margins of said fabric strip.

10. A coil of a length of the flexible connector duct material of claim 9.

11. A flexible connector duct blank as recited in claim 9, wherein the free width of the fabric exceeds the width of the metal strip measured within the opposite side boundaries of said free width.

12. Flexible connector duct blank adapted to provide flexible connector duct material having two elongated metal strips each having a side marginal portion bent into securement with an opposite side margin of a fabric strip upon longitudinal cutting of a single metal strip, said blank comprising: a single elongated metal strip, the side marginal portions of said metal strip being bent over, a longitudinally extending folded strip of fabric non-adhesively superimposed upon said metal strip between the bent over marginal portions thereof, said bent over marginal portions of said metal strip being bent into engagement with the side margins of said fabric strip with the free width of the fabric being in excess of the width of the metal strip measured within the opposite side boundaries of said free width.

13. A coil of a length of the flexible connector duct material of claim 12.

References Cited in the file of this patent UNITED STATES PATENTS 1,056,017 Flora Mar. 18, 1913 1,175,236 Cary Mar. 14, 1916 1,244,985 Kipniss Oct. 30, 1917 1,501,389 Baker July 15, 1924 1,691,491 Nelson Nov. 13, 1928 1,727,184 Thompson Sept. 3, 1929 1,756,448 Bigney Apr. 29, 1930 1,864,929 Peterson June 28, 1932 2,109,921 Leach Mar. 1, 1938 2,564,900 Henriksen Aug. 12, 1951 2,777,573 Goldsmith Jan. 15, 1957 2,781,816 Lawson Feb. 19, 1957 2,781,818 Beckman Feb. 19, 1957 2,782,914 Giles Feb. 26, 1957 2,825,38 Goldsmith Mar. 4, 1958 TENT OFFICE ORRECTION January 23,1962

UNITED STATES PA CERTIFICATE OF C Patent No, 3,01%694 Morris Goldsmith are in the above numbered pat- It is hereby certified that error appe t should read as ent requiring correction and that the said Letters Paten corrected below.

Column 1, line-o7 for "meal" read metal column 2 line 8, after "fabric" insert strip 5 column 6 line 15,

d affected --3 line 73) strike out for "effected"-= rea fabric first occurrence.

Signed and sealed this 7th day of August 19620 (SEAL) Attestz' DAVID L. LADD ERNEST W. SWIDER Commissioner of Patents Attesting Officer

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