FIELD OF THE INVENTION

The field of this invention relates to the art of cutting boards especially fiberglass boards having a foil backing on one surface thereof. The apparatus and method involve removing strips of fiberglass from a substantially- planar duct board whereupon the board can be fo ~lded into a polygonal or rounded shape and a longitudinal joint sealed to make a duct section. BACKGROUND OF THE INVENTION The art of board cutting machines has been under development for many years. Early attempts were in the field of cardboard cutting and usually involved a plurality of feed rolls moving a piece to be cut across a stationary knife. Typical of such machines are those disclosed in U.S. Patents No. 810,971; 442,878; 667,055; and 527,963. Other cutting machines used variations of the moving piece-stationary blade configuration by incorporating additional features such as reciprocation of a blade as the piece was pushed across the blade. One such machine is disclosed in U.S. Patent 2,565,400. More recently, machines were proposed specifically for the task of cutting fiberglass duct board having an impermeable barrier such a foil on one face. These machines, just as the earlier cardboard cutting machines, employed drive rollers to move the fiberglass board across a stationary blade. Typical of these machines are U.S. Patents 3,941,018; 4,091,697; 3,996,824 and 3,605,534.

The board cutting machines employing a movable piece with stationary blades presented numerous drawbacks. Fiberglass duct board is manufactured in rectangular- sheets usually eight feet (2.44 meters) by ten feet (3.05 5 meters). These devices, such as discussed in the Barr 3,605,534 patent, employed a multiple number of blades which removed a plurality of parallel strips from the board. Thereafter, the board could, upon removal from the machine, be folded and sealed along a longitudinal joint

10 to form a duct section. However, for each different size duct that had to be cut, the blades required repositioning. Additionally, in view of the fixed size of the fiberglass board which could be purchased, even the most meticulous amount of calculation still resulted in

15 scrap pieces generated by cutting each board. Such pieces were unusable to manufacture another piece of duct. These small scrap pieces were used as duct end caps or simply thrown away.

Apart from the waste generated by board cutting

20 machines employing stationary blades with a driven duct board, additional problems ensued. On a typical building construction job ducts of various sizes are required. In order to fabricate ducts of differing sizes, the machines employing stationary blades and a driven fiberglass board

25 required frequent resetting of blade positions along a carriage. The i preciseness of the setting method coupled with its inherent dependence on operator skill to properly set the blade positions, resulted in additional waste being generated.

30. Other machines for board cutting employed a

.stationary board with movable blades. These machines did not provide for or anticipate any method of reducing waste as a result of cutting duct sections out of a board of fixed dimensions. Typical of such machines are U.S.

35 Patents 532,822; 2,436,111; 1,117,577; 3,515,019 and

3,242,780. Although these machines employed a stationary board with blades movable on a carriage across the board,

they still had significant drawbacks. Importantly, all incorporated a materials handling problem. The duct board had to be loaded individually, sheet by sheet, onto an easel type structure whereupon the carriage holding the blades would be driven across the sheet. Each time a different size duct was to be cut, the blades had to be realigned along the carriage. Furthermore, the machines such as that disclosed in U.S. Patent 2,436,111 employed a cutting motion along the long dimension of a board which usually involved leaving a thin unusable strip at one edge of the board. The Reid 3,242,780 patent had the ability to cut a stationary board along the long or short dimension but involved a cumbersome loading procedure involving vacuum cups to retain the piece while it was being cut as well as frequent adjustments of blade positions to prepare different size ducts.

Known board cutting machines regardless of whether they employed stationary blades with a moving board or a stationary board with moving blades suffered from various drawbacks. As previously mentioned, the waste problem was prevalent in either design. Additionally, it was not possible to quickly mass produce large quantities of duct of varying size for a particular job in view of the frequent blade repositionings necessary and the cumbersome loading procedure. Frequently, machines involving stationary blades and a moving board had to be fed one board at a time by an individual operator. Such machines, manufactured by the Glass Master Corporation of San Antonio, Texas have recently been in use. One such machine called Autogroover uses computer control to reposition blade along the carriage to cut different size duct. Despite such automation, the Autogroover still generated waste and had to be fed by an operator one board at a time. Not only has scoring the duct board presented several problems, but folding the scored duct board into a duct section has, in the past, involved complex and cumbersome

machinery. The types of cuts employed in the past are illustrated in Figs. 11-14 of U.S. Patent 3,605,534 as well as Fig. 8 of U.S. Patent 3,515,019. Fig. 8 (Item 100) of the U.S. Patent 3,515,019 illustrates what is 5 known as a V-groove cut while Fig. 12 of U.S. Patent 3,605,534 illustrates a shiplap cut. Fig. 13 of U.S. Patent 3,605,534 illustrates a flap cut which acts in combination with the cut displayed in Figs. 11 or 14, of U.S. Patent 3,605,534, to make a closure joint. It has

10. been found that shiplap cuts, employed as corner joints of a duct do not present sufficient joint rigidity to prevent a folded duct in the shape of a rectangle from twisting with respect to its longitudinal axis or otherwise failing to retain its shape. To overcome this problem, a duct-

15 such as that shown in Fig. 2 of U.S. Patent 3,605,534 was folded into a rectangle and then pushed beyond its rectangular shape into a parallelogram shape before a longitudinal joint was taped. Taping a longitudinal joint while the duct was held in a parallelogram configuration

20 allowed the duct to snap back to a rectangular shape. As a result of the stresses imposed on all the corners due to overbending while taping, the duct exhibited additional structural rigidity against twisting or buckling along any of its corners. Elaborate machines were built to retain

25 the duct to be taped in a parallelogram position for taping. One such device is disclosed in U.S. Patent 4,070,954.

Machines .for feeding duct boards to be cut have also been developed. They had the shortcomings of being highly

30 complex mechanically and used a substantially closed - structure allowing loading of the machine from only one direction. When handling a pallet with a large stack of boards, greater maneuvering access than those known machines could provide was often required. U.S. Patent -5 3,875,835 discloses such a loading machine. SUMMARY OF THE INVENTION

The apparatus and method of the present invention employ a plurality of frame mounted rollers to move a board. A plurality of cutting blade assemblies are movable in a direction transverse to board movement across the machine. 5 A control system positions the board adjacent the cutting blade assemblies. The cutting blades are actuated to cut the board transversely to its direction of movement through the machine while the board is being held stationary. The machine is continuously fed, one board at

IJO a time with the butt joint between boards being taped as an integral step in the cutting procedure. Boards to be cut are stacked and fed one at a time to be cut after proper alignment. The interaction between the rollers and the control system results in proper indexing of the board

15 to make a plurality of strip cuts from the board. Each scored board has a shiplap cut at one end, a flap cut at the opposite end, and a plurality of modified shiplap cuts in between. After the strips are cut, the boards are folded into substantially a rectangular or square shape

20 whereupon a taper applies tape over a flap to seal a longitudinal joint thereby creating a section of duct. BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view of the board cutting machinery illustrating the loading, cutting and sealing

25 operation;

Fig. 2 is a plan view of the power driven push bar of the board feeding means taken along lines 2-2 of Fig. 1;

Fig. 3 is a sectional elevation of the board cutting apparatus, taken along line 3-3 of Fig 1, illustrating the

30 board support means and the cutter means;

Fig. 4 is the front elevational view of the board inlet as seen along lines 4-4 of Fig. 3;

Fig. 5 is a detailed view of the cutter means illustrated in Fig. 3;

35 Fig. 6 is a detailed elevational end view of a cut board after emerging from the board outlet as shown in Fig. 3;

-6-

Fig. 7 is .an assembled elevational end view of the duct in Fig. 6 showing the duct section ready to be taped along a longitudinal joint;

Fig. 8 is a detailed perspective view of the blades used to make a modified shiplap cut;

Fig. 9 is an alternate view of the blades shown in Fig. 8;

Fig. 10 is a detailed perspective view of the blade carriage having a flap blade, a shiplap blade and a board ripping blade thereon;

Fig. 11 is an alternate view of the blade assembly shown in Fig. 10;

Fig-. 12 is a front elevational view of the board sealing apparatus taken along lines 12-12 of Fig. 1; Fig. 13 is a detailed view of the tape carriage on the board sealing apparatus as shown in Fig. 12 and the tape carriage for the joining means as shown in Fig. 4;

Fig. 14 is a section through lines 14-14 of Fig. 13. DESCRIPTION OF THE PREFERRED EMBODIMENT The apparatus and method of the present invention relate to the board cutting and forming boards into a duct section. Preferably, fiberglass duct boards are to be grooved on one face with the opposing face being a foil backing. The apparatus A is illustrated in Fig. 1. The components of the apparatus are as follows: board feeding means B; joining means J (Figs. 1 and 4); board support means S (Fig. 3); cutter means C (Fig. 3); sealing means T; and control means D.

Referring to Figs. 1 and 2 board feeding means B has an open frame 10a having a horizontal component 10b disposed parallel to a fixed support surface such as a working floor. It is generally desirable to secure open frame 10a by fixing horizontal component 10b to a working surface by means well known in the art. A substantially vertical component 10c extends from one end of horizontal component 10b of open frame 10a. Moving means M includes, a drive assembly lOd preferably housed adjacent the top of

vertical component 10c, said drive assembly lod further includes drive motor lOe. A pair of arms lOf and lOg comprise a movable platform which can support a stack of duct boards lOh thereon. It is understood that a solid platform may be employed in lieu of arms lOf and lOg without departing from the spirit of the invention. It has been found that fiberglass duct boards having a thickness of approximately one inch (2.54 cm) contain sufficient structural rigidity to be supported by a pair of arms. Alternatively, a pallet supporting a stack of boards lOh can be placed on arms lOf and lOg. The use of a pair of arms lOf and lOg instead of a solid platform reduces the overall weight of board feeding means B. Vertical component 10c preferably includes a worm-type drive for selectively raising and lowering arms lOf and lOg in tandem. Selective operation of drive motor lOe which cooperates with drive assembly lOd and the drive components located within vertical component 10c, results in upward or downward movement of arms 10f and lOg. The details of the drive which translates rotation of motor lOe into movement of arms lOf and lOg are not illustrated and are known to those of ordinary skill in the art.

By means of an electric eye, proximity switch, or other suitable motion detection devices, the topmost board lOi of stack lOh is raised to the appropriate horizontal plane for feeding to the board support means S (Fig. 3). Having attained the appropriate elevation for topmost board lOi (Fig. 3) via moving means M, pushing means P can be employed to feed board lOi toward board inlet 20b for cutting.

As seen in Fig. 2, pushing means P is pivotally mounted to drive assembly lOd through a linkage lOj . Linkage lOj preferably contains a pair of links of equal length, 10k and 10m. Pushing means P further includes a push bar lOu having a pushing surface lOn (Fig. 2).

Pushing surface lOn has a rearward extending section lOp with links 10k and 10m pivoted respectively at points lOq

and lQr. When pushing means P preferably actuates link 10k for rotation, topmost board lOi (Fig. 3) is displaced in two directions as shown by arrows 10s and lot. The dashed lines in Fig. 2 illustrate that when push bar lOu is actuated, pushing surface lOn translates along an edge lOv of topmost board lOi in direction of arrow lot. Additionally, pushing surface lOn urges topmost board lOi in the direction of arrow 10s. The component of force exerted by pushing surface lOn on edge lOv in the direction of arrow lot forces board lOi against alignment means E (Fig. 1).

Alignment means E can consist of a unitary or segmented guide bar(s) lOw having a guide surface(s) lOx thereon. Guide surface lOx is disposed parallel to edge lOy (Fig. 1) of topmost board lOi in stack lOh. As a result of the translation of pushing surface lOn along edge lOv, the topmost board lOi is urged not only in the direction of arrow 10s but also up against guide surfaces lOx so that the proper alignment of board lOi is maintained as it is being driven in direction 10s.

Pushing means P operates in a fixed horizontal plane (Fig. 1). When arms lOf and lOg raise topmost board lOi to the proper elevation, pushing means P can push topmost board lOi towards board inlet 20b. The operation of pushing means P in a fixed, horizontal plane elevated from a working floor, allows board feeding means B to be loaded with a stack of boards lOh from the direction of arrows- lOz and lOaa (Fig. 1).

The ability to load board feeding means B from two separate directions at least ninety degrees apart allows additional flexibility in placement of board feeding means B. It will be appreciated that as presently available in the- U.S.A., duct board is supplied in sheets that are as large as ten feet (3.05 meters) by eight feet (2.44 meters), with a stack containing as many as forty-eight sheets. As a result, considerable room is required to maneuver a stack so that it can be loaded onto arms 10f and. lOg.

As shown in Figs. 1 and 3, board feeding means B can continue to feed from the stack of boards lOh until the last board is fed into board inlet 20b. At that moment, a suitable alarm is sounded and control means D stops the board support means B and cutter means C to allow board feeding means B to be adjusted to receive another stack of boards lOh. As seen in Figs. 3 and 4, the topmost board lOi is abutted to a preceding board 20, which is retained by board support means S for cutting with cutter means C. Control means D not only regulates the movement of board support means S but senses the position of trailing edge 20a of board 20. When trailing edge 20a is placed in close juxtaposition with joining means J, control means D stops of board support means S so that joining means J can effectively connect board 20 to board lOi before cutting operations with cutter means C are resumed.

Joining means J (Fig. 4), includes a mounting rail 20c secured to frame 20d. Mounting rail 20c extends transversely to the direction of board movement through board support means S, as indicated by arrow 20e (Fig. 3). Carriage 20f (Fig. 4) is drivably mounted for translation in two directions along mounting rail 20c. Carriage 20f further includes a rotatably mounted tape spool 20g which holds a supply of heat sealable tape 20h thereon. Tape 2Oh is threaded from tape spool 20g under leading heat roller 20i and trailing heat roller 20j . An intermediate idler roller 20bb may be employed between spool 20g and leading heat roller 20i. A cutting apparatus 20k is disposed between leading heat roller 20i and trailing heat roller 20j . The cutting apparatus 20k is illustrated in Figs. 4 or 13 and generally includes a vertically oriented blade which, in combination with appropriate springs and solenoids can be actuated to travel downwardly to sever tape 20h when carriage 20f has traversed the entire butt joint 20m (Fig. 3) between board 20 and board lOi.

When control means D senses that trailing edge 20a of board 20 is in alignment with tape 20h on joining means J,

further movement of board support means S is curtailed. It wilL be appreciated that as board 20 is driven from board inlet 20b to board outlet 20n of frame 20d, pushing means P maintains board lOi in constant contact with 5 trailing edge 20a.

Upon proper juxtaposition of butt joint 20m, control means I actuates a drive (not shown) causing carriage 20f to translate along mounting rail 20c. Leading and trailing heat rollers 20i and 20j have their lowermost Q point slightly below the upper face 20p of board 20.

Upper face 20p contains the foil backing. As a result of movement of carriage 20f (Fig. 4) from right to left, leading and trailing rollers 20i and 20j slightly compress butt joint 20m against an underlying support 20q (Fig. 3) ^" which is preferably integral with frame 20d. Leading heat roller 20i has a thermostatically controlled heat source 20r therein and is preferably set at a approximately two hundred fifty degrees Fahrenheit. Trailing heat roller 20j has a similar thermostatically controlled heat source 0 20s and is preferably set at five hundred fifty degrees Fahrenheit. The neutral position of carriage 20f is illustrated in Fig. 4.

The operation of cutting apparatus 20k can be further understood by a close examination of Fig. 13. Cutting 5 apparatus 20k includes a vertically disposed cutting blade 20t secured to carriage 20u which is guided by guide 20v. Solenoid 20w has a piston 20x which is connected to carriage 20v. Spring 20y resists the movement of piston 20x of solenoid 20w. In operation, actuation of solenoid 20w results in inward retraction of piston 20x into the solenoid 20w which overcomes the spring force of spring 20y and results in downward movement blade 20t to sever tape 20h. When the solenoid is deenergized, spring force exerted by spring 20y lifts carriage 20u as piston 20x is extended from solenoid 20w. It can be readily appreciated by those skilled in the art that alternative means of

actuatioπ of blade 20t can be employed without departing from the spirit of the invention.

Operating problems may ensue in using solely one heating roller set at a sufficiently high temperature to 5 completely seal and set heat sensitive tape 2Oh. In applications employing only a single roller set at a sufficiently high temperature to seal and set the tape, remnants of tape 20h cling to blade 20t during cutting thereby preventing further efficient cutting of tape 20h

10 for subsequent operations. As a result, the apparatus of the present invention employs staged heating wherein the leading heat roller 20i (Fig. 4) is set at a lower temperature than the trailing heat roller 20j. As a result, when blade 20t is actuated to sever tape 20h at

15 edge 20z (Fig. 4) of board 20, the tape is still tacky and does not stick to blade 20t. After completion of the taping of a butt joint 20m, carriage 20f is driven to its neutral position shown in Fig. 4. The return motion, timed by control means D, is executed when board support

20 means S is stationary, in order to avoid any damage to the foil backing.

Referring to Fig. 3, board support means S includes a pair of inlet rollers 30a and 30b. Rollers 30a and 30b are disposed transverse to the direction of board movement

25 as shown by arrow 20e and are secured to frame 20d. Rollers 30a and 30b have longitudinal center lines disposed in a common vertical plane with roller 30a disposed above upper face 20p of board 20. Roller 30b is. disposed directly below roller 30a such that board 20 is

3.0 slightly pinched by rollers 30a and 30b. Board support means S further includes a pair of outlet rollers 30c and 30d disposed adjacent board outlet 20n and secured to frame 20d. Outlet rollers 30c and d extend in a direction transverse to board movement as illustrated by arrow 20e.

35 Outlet rollers 30c and d pinch board 20 therebetween for proper indexing and movement of the board through frame 20d as will be more fully explained hereinbelow. Although

only two rollers are shown to act as inlet rollers and two rollers as outlet rollers, those skilled in the art will appreciate that additional rollers may be employed to support and move the board through frame 20d. In the 5 preferred embodiment, rollers 30a through d provide two functions of supporting the board through frame 20d, as well as moving the board in the direction of arrow 20e. The amount that rollers 30a and b or rollers 30c and d pinch board 20 can be varied. By example and not by way

10 of limitation, the spacing between rollers 30a and b and rollers 30c and d can be set at three quarters of an inch (1.875 cm) for a nominally one inch (2.54 cm) thick board. Control means D regulates the rotation of rollers 30a through d. Proper indexing of the board with respect to

15 cutter means C is accomplished using control means D to drive rollers 30a through d in tandem. However, occasions may arise wherein all the boards for a particular job have been cut, yet one board 20 still remains within frame 20d secured by rollers 30a through d. In that event, should a

20 subsequent production run not be immediately required, it is advantageous to advance the board which was last cut through board outlet 2On while retaining any remnants of that board held firmly between inlet rollers 30a and 30b. To accomplish this, control means D senses when a job is

25 complete, and selectively drives outlet rollers 30c and 30d independently of inlet rollers 30a and 30b, thereby driving the final board which has been cut through board outlet 20n. The remaining portion of the board 20 is held fixedly by inlet rollers 30a and b. When the next

30. production run is initiated, the remnant of the board 20 held by inlet rollers 30a and b is already properly indexed with respect to cutter means C to allow the automatic start of the next production run. It should be noted that the remaining board remnant will already have a

25 leading shiplap cut thereon, as shown by surfaces 70a and b in Fig. 6. The special procedure required for insertion of an initial board into frame 20d so that it is securely

held by inlet rollers 30a and b and outlet rollers 30c and d will be described in more detail hereinbelow.

Cutter means C (Fig. 3) is disposed between inlet rollers 30a and b and outlet rollers 30c and d adjacent to board 20. As shown in Fig. 3, upper face 2Op contains the foil backing with cutter means disposed below board 20 for removal of strips 40a. Those skilled in the art will appreciate that board 20 can be fed through frame 20d with the foil side down and cutter means C disposed above the board 20. However, it is preferred to have cutter means C below the plane of board movement so that strips 40a can drop or be easily tapped out of board 20 while board 20 is suspended above a suitable receptacle 40b.

Cutter means C further includes first, second and third blade rails 40c-e, respectively (Fig. 3). Each of blade rails 40c-e has a carriage thereon labeled 40f-h, respectively (Fig. 5). As seen in Figs. 3 and 5, carriage 40f is preferably disposed between carriages 40g and 40h with carriage 40g closest to board inlet 20b and carriage 40h disposed closest to board outlet 2On. All three carriages 40f-h are aligned in an identical horizontal plane. Blade rails 40c through e are each disposed in a direction transverse to the direction of board movement through frame 20d. Control means D coordinates the movements of board support means S to position board 20 adjacent carriages 40f through h for cutting strips 40a therefrom. Each carriage, 40f through h, has a blade assembly 40i-k, respectively, thereon (Fig. 5).

Carriage 40f is shown in more detail in Figs. 10 and 11 and for the purposes of description will be referred to as the first carriage. First carriage 40f includes a flap cutting blade 40m, a shiplap blade 40n and a board ripping blade 40p. Board ripping blade 40p is designed to cleanly slit through the board including the foil backing upon movement of carriage 40f.

Board ripping blade 40p extends from carriage 40f in a plane perpendicular to board movement through frame 20d. Blade 40p has a pair of opposed cutting edges 40q and 40r which are adjacent to each other and meet at point 40s.

Board. ripping blade 40p is adapted for bidirectional cutting. Cutting edge 40q is rearwardly inclined with respect to movement of carriage 40f as the board ripping blade cuts in one direction while cutting edge 40r is 5 rearwardly inclined with respect to movement of carriage 40f in the opposite direction, for cutting completely through- board 20 including the foil backing on upper surface 20p. Both cutting edges 40q and 40r are double beveled as shown in Figs. 10 and 11 by beveled surfaces

Iff 40t and 40u, respectively. Retaining bar 40v is disposed immediately above upper face 20p to prevent board 20 from riding up board ripping blade 40p during cutting. The tendency of board 20 to ride up is increased as blade 40p gets progressively duller.

15 Carriage 40f also includes a shiplap blade 40n.

Shiplap blade 40n has a first segment 50a extending from carriage 40f in a direction perpendicular to the plane of board movement. A second segment 50b extends from the free end of first segment 50a in a direction substantially

20 perpendicular thereto. That is, second segment 50b runs substantially parallel to upper surface 2Op of board 20 as carriage 40f is moved in either of two directions transverse to the direction of board movement through frame 20d. As seen in Fig. 5, second segment 50b 5 intersects the plane of board ripping blade 40p. Both first segment 50a and second segment 50b each have a pair of opposed cutting edges with edges 50c and d disposed on first segment 50a and edges 50e and f disposed on second segment 50b. When carriage 40f is driven in one direction 0 and cutting edges 50c and 50e are cutting, such edges are rearwardly inclined in the direction of movement of carriage 40f. Similarly, when carriage 40f is driven in the opposite direction and edges 50f and 50d are cutting, such edges are rearwardly aligned in the direction of 5 movement of carriage 40f. Cutting edge 50c is disposed at a spaced relationship to cutting edge 50d, while cutting edge 50e is disposed adjacent to cutting edge 50f as noted

by their ^* intersection point 50g (Fig. 11). As seen by comparing Figs. 10 and 11 both first segment 50a and second segment 50b are single beveled as indicated by beveled surfaces 50h-k (Fig. 10). The significance of single beveling shiplap blade 40n will be discussed in more detail hereinbelow.

First carriage 40f further includes flap blade 40m. Flap blade 40m has a first segment 60a extending from carriage 40f in a plane perpendicular to a direction of board movement through frame 20d. Second segment 60b extends from the free end of first segment 60a and in a plane substantially parallel thereto. As a result, second segment 60b is disposed substantially parallel to upper face 20p of board 20 which includes the foil backing. First segment 60a has opposed cutting edges 60c and d thereon and second segment 60b has opposed cutting edges 60e and f thereon. As can be seen from Fig. 11, when carriage 40f is moving in one direction and cutting edges 60d and 60f are cutting board 20, such edges are rearwardly inclined with respect to the direction of carriage movement. Similarly when the carriage 40f is moving in the opposite direction and cutting edges 60c and 60e are cutting board 20, such edges are rearwardly inclined with respect to the direction of movement of carriage 40f. Cutting edges 60d and 60c are disposed at a spaced relation to each other while cutting edges 60f and 60e are adjacent to one another meeting at intersection point 60g. As can be seen in Fig. 5, second segment 60b of flap blade 40m intersects the plane of board ripping blade 40p. Second segment 50b of shiplap blade 40n is parallel but below second segment 60b of flap blade 40m. Additionally, as seen in Figs. 10 and 11, shiplap blade 40n is offset from flap blade 40m as shown by the misalignment of intersection points 50g and 60g in a direction parallel to movement of carriage 40f. Flap blade 40m and shiplap blade 40n are both offset from board ripping blade 40p in a direction parallel to movement of

carriage 40fT. Cutting edges 60c -f are single beveled as indicated by beveled surfaces 60h-k (Fig. 11).

The cuts made by the blades on carriage 40f are illustrated in Fig_ 6. Shiplap blade 40n makes the 5 leading cut as illustrated by surfaces 70a and b of Fig. .6. As shown in Fig. 6, a quadrilate ally shaped strip 40a is removed from the board adjacent its leading edge 20aa. Board ripping blade 40p and flap blade 40m make the last two cuts along the trailing end 20a of board 20. As shown 0 in Fig. 6, flap blade 40m removes a strip 40a, indicated by dashed lines, thereby leaving exposed, surface 70c and an overhanging flap 70d of foil backing. It can readily be appreciated that edges 60d or 60c are responsible for creating surface 70c while cutting edges 60f or 60e cut 5 parallel but immediately below the foil of upper surface 20p to remove, in a quadrilaterally shaped strip 40a, substantially all the fiberglass below the backing at upper surface 20p. Similarly, at the leading edge 20aa of board 20, cutting edges 50c or 50d create surface 70b 0 while cutting edges 50e or 50f create surface 70a.

Finally, board ripping blade 40p severs the backing and cuts through the entire board at trailing edge 20a.

As seen in Figs. 6, 10 and 11, the removal of a strip 40a from the trailing edge 20a requires the strip 40a to 5 pass between carriage 40f and the underside of .second segment 60b. The other two parallel sides of strip 40a to be removed from tailing edge 20a must pass adjacent to surfaces 40v and 60m, of the board ripping blade 40p and flap blade 40m, respectively. Similarly, when making the Q cut adjacent leading edge 20aa, the quadrilaterally shaped . strip 40a must be passed between carriage 40f and underside of second segment 50b of shiplap blade 40n. The other two surfaces must pass between surface 40bb of board ripping blade 40p and 50m of shiplap blade 40n. In order 5 to minimize compression of a strip 40a which is cut by either flap blade 40m or shiplap blade 40n, the surfaces of such blades are single beveled to minimize compression

-L7-

between opposing surfaces 40v and 60m, 40bb and 50m as well as between second segments 50b or 60b and the carriage 40f. Past designs have experienced clogging of fiberglass between blades between blades and a carriage due to this compressive force. By beveling the cutting surfaces of flap blade 40m and shiplap blade 40n on the sides that look away from the strip to be cut, compression in a plane perpendicular to the movement of carriage 40f is minimized thereby reducing clogging problems as the strips 40a are cut from the board. To further reduce the possibility of clogging, the blades on carriage 40f are offset in a plane parallel to the movement of carriage 40f (Figs. 10 and 11) illustrate the offset of points 40s, 50g .and 60g. The blade assemblies 40j and 40k are disposed, respectively, on second and third carriages 40g and 40h. These assemblies present a significant improvement in the art of blade design with respect to cutting fiberglass boards. In the aggregate, blade assemblies 40j and 40k make what is aptly described as a "modified shiplap cut" . As seen in Fig. 5, blade assemblies 40j and 40k are identical with the mounting of the individual blades reversed. Specifically, both carriages 40g and 40h include a shiplap blade 40n as previously described. On carriage 40g, shiplap blade 40n is mounted to the carriage on an end closest to board inlet 20b, whereas on carriage 40h shiplap blade 40n is mounted on the end of the carriage closest to board outlet 2On.

Figs. 8 and 9 illustrate the shiplap blade 40n with the modified shiplap blade 80a as shown on carriage 40h of Fig. 5. Modified shiplap blade 80a has a first segment 80b which extends from carriage 40h perpendicular to the plane of board movement through frame 20d. The second segment 80c extends from the free end of first segment 80b and in a plane inclined with respect to first segment 80b. Third segment 80d extends from the end of second segment 80c, opposite from first segment 80b, and downwardly

toward carriage 40h, thereby defining an included and acute angle 80t- between- second segment 80c and third segment 80d. Although many angle configurations can be used, the preferred angles are an included angle of 130° 5 between first segment 80b and second segment 80c and an included angle of 54° between second segment 80c and third segment 80d. As seen in Fig. 5, third segment 80d intersects the plane of second segment 50b of shiplap blade 40n. As seen, in Figs. 8 and 9, modified shiplap

Iff blade 80a has opposed cutting edges 80e and 80f on first segment 80b. Opposed cutting edges 80g and 80h are disposed on second segment 80c. Opposed cutting edges 80i and 80j are disposed on third segment 80d. When carriage 40h travels in one direction, cutting edges 80e, 80h, and

15 80j cut the duct board and are rearwardly inclined with respect to the direction of motion of carriage 40h. Conversely, when carriage 40h is driven in the opposite direction, cutting edges 80f, 80g and 80i cut the duct board and are rearwardly inclined with respect to the

20 direction of motion of carriage 40h. All cutting edges on modified shiplap blade 80a are single beveled as illustrated by beveled surfaces 80k, 80m, 80n, 80p, 80r and 80s (Figs. 8 and 9). Cutting pairs 80e and 80f as well as 80g and 80h are spaced from each other while

25 cutting edges 80i and 80j are adjacent to each other meeting at a point 80u.

As previously indicated, the blades on carriage 40g are identical to 40h but are mounted in a reversed relationship. The cuts made by carriages 40g and 40h are

20 ^" illustrated in Fig. 6. Carriage 40h removes a strip 40a defined by remaining surfaces 70e-i. The cuts made by carriage 40g in removing a strip 40a are indicated on Fig. 6 by remaining surfaces 70j, k, m, n, and p. The preferred sequence of cuts on any piece of board is as 5 follows: blade 40n of carriage 40f; blade assembly 40k of carriage 40h; blade assembly 40j of carriage 40g; blade

assembly 40k of carriage 40h; and flap blade 40m and board ripping blade 40p of carriage 40f.

The intersection of remaining surfaces 70f and 70g as well as remaining surfaces 70m and 70n, occurs adjacent 5 but below the foil backing at upper face 20p of board 20. The modified shiplap cuts made by blade assemblies 40j and 40k and illustrated in Fig. 6 represent a marked improvement from the known shiplap or V-groove cuts used in the past. V-groove cuts offered longitudinal rigidity

10 when the board was folded into a rectangular duct section. The major disadvantage of V-groove joints is that they make it extremely difficult to effectively join a lateral duct to a main duct and obtain a good seal. Shiplap joints presented an improvement over V-groove joints in

15 that a sidewall can be cut out to insert a branch duct as shown in Fig. 4 of U.S. Patent 3,605,534. However, as previously described, the use of shiplap cuts builds in an inherent looseness in each shiplap joint which requires that a duct be folded into a rectangular shape and then

20 further distorted into a parallelogram shape before taping. This overbending is required to allow the taped duct to spring back to its rectangular shape after taping thereby removing any slack in the shiplap joints and resulting in enhanced longitudinal rigidity of the duct

25 section and improving its ability to resist twisting along a longitudinal axis. Accordingly, large machines, as shown in Fig. 1 of U.S. Patent 4,070,954, are required to hold a folded duct in the parallelogram position for taping.

3.0 The modified shiplap cut made by blade assemblies 40j and 40k represents an improvement over blade designs in the past by incorporating the beneficial features of both the V-groove and the shiplap cut in one unitary cut. The modified shiplap cut made by blade assemblies 40j and 40k

35 permits easy insertion of lateral ducts by removing any one of panels 70q or 70r (Fig. 7) and inserting a branch duct having a male end therein in the manner shown in Fig.

4- of U.S. Patent 3,605,534. Additionally, the cut board as illustrated in Fig. 6 can be folded into a rectangular shape (or square shape) as shown in Fig. 7 and taped while held in that position. The closure of the longitudinal shiplap joint 70s with flap 70d can thus be accomplished using far simpler machinery than that previously known. In addition to the simplified closure procedure, the folded duct board retains its longitudinal strength and resistance to twist buckling along its longitudinal axis without any need to fold the duct into a parallelogram shape, tape it, and allow it to spring back to a rectangular shape.

The modified shiplap cut made by blade assemblies 40j and 40k has other advantages over blade assemblies previously used. The included angle 80t between second segment 80c and third segment 80d acts to minimize clogging of a strip being cut in that the angular disposition of second and third segments 80c and 80d imparts and downward force toward carriage 40h or 40g on the strip 40a being cut. The downward force tends to minimize clogging of modified shiplap blade 80a as carriage 40g or 40h is moved across the board 20 in either direction. To further minimize clogging of a strip 40a to be removed by blade assemblies 40j or 40k, the shiplap blade 40n is offset in the plane of carriage movement, from the modified shiplap blade 80a on both carriages 40g and 40h as seen by the positions of points 80u and 50g (see Figs. 8 and 9). Additionally, the single beveling of cutting edges 80e-j as well as all the cutting edges 50c-f of shiplap blade 40n further reduces compressive forces on a strip to be removed by carriages 40g or 40h. These compressive forces exist between surface 50m and first segment 80b; between second segment 50b and the carriage 40g or 40h; and between second segment 80c or third segment 80d and the carriage 40g or 40h. These compressive forces generally act in a plane perpendicular to the movement of carriages 40g and 40h. As seen in

Figs. 8 and 9, the beveled edges of modified shiplap blade 80a and shiplap blade 40n all occur on the faces of such blades looking away from the strip to be cut thereby assuring that the actual dimensions of the strip cut are as close as possible to the actual clearance dimensions between modified shiplap blade 80a and shiplap blade 40n as well as the carriage supporting those two blades.

After the boards 20 are scored, sealing means T is employed to effectively close such scored boards into duct sections. In a typical heating, ventilating and air conditioning job, it is desirable to precut a stack of boards lOh into individual segments 20 (Fig. 3) and ship the scored boards to a job site. At the job site, each flat scored board 20 can be folded into a rectangular shape as shown in Fig. 7 and sealed by sealing means T. Since sealing means T may be required on various job sites, it is advantageous to employ a lightweight construction to allow simple and efficient closure of longitudinal joints 70s for each board 20. It is understood that, alternatively, the scored boards 20 can be folded and taped into duct sections at a location remote from point of installation and shipped thereto by truck or other suitable means.

As best seen in Figs. 1 and 12, sealing means T includes a frame 90a having a movable platform 90b thereon. Frame 90a further includes a backstop 90c which has a horizontal component 90d extending in a plane parallel to movable platform 90b. A duct segment 20 is folded into the shape shown in Fig. 7 by hand or by machine after strips 40a are removed therefrom (see Fig. 3). The folded duct board 20 is placed on movable platform 90b with longitudinal joint 70s positioned as shown in Fig. 14. Actuating controls 90e selectively raises movable platform 90b until such time as horizontal component 90d contracts flap 70d and presses it firmly against panel 70t- When the folded duct is raised with platform 90b to the position shown in Fig. 14, further

movement of platform 90b is curtailed via controls 90e. At this time, the duct section is ready to be sealed.

A. sealing carriage 90f is mounted on mounting rail 90g. Mounting rail 90g is disposed parallel to longitudinal joint 70s which is to be taped closed. The internal details of the tape dispensing and cutting elements found on carriage 90f are preferably identical in construction and operation to carriage 20f illustrated in Fig. 13 and described hereinabove. As ^' shown in Fig. 1, a stapling gun 90h of a type known in the art can be incorporated into carriage 90f (as well as carriage 20f), if desired, on certain applications. However, in the preferred embodiment sealing the longitudinal joint 70s with tape only is satisfactory for almost all heating, ventilating and air conditioning applications today. with the horizontal component 90d holding flap 70d firmly against panel 70t, carriage 90f is actuated by control 90e to traverse across flap 70d to seal flap 70d to panel 70t along the outer foil. As previously described, suitable position sensing devices actuate the cutting blade on carriage 90f when it is aligned with the end of the joint as represented by the carriage having traversed from the right end to the left end of Fig. 12. As seen in Fig. 14, translation of carriage 90f slightly compresses the flap 70d against panel 70t which helps in holding the duct in place during sealing and further provides adequate contact between the heating rolls on carriage 90f and the tape being applied underneath them to flap 70d and panel 70t. In order to further improve the contact between the heating rolls on carriage 90f, an iron 90i (Fig. 12) may be employed to further smooth down tape 70d against panel 70t. It should be recognized that carriage 90f only tapes a longitudinal joint when moving from right to left as shown in Fig. 12. After taping a longitudinal joint 70s, platform 90b is lowered via controls 90e and the next folded duct section is placed on platform 90b for taping. The folded duct sections are

placed on platform 90b in a substantially rectangular shape, that is, having substantially square corners. The ability to tape a duct section while it retains a substantially rectangular or square shape without overbending, as in the past, makes possible the employment of sealing means T having a far simpler construction than that employed in the past.

In operation, the board cutting is initiated by loading a stack, of boards lOh on arms lOf and lOg. The stack lOi is then raised via moving means M such that a topmost board lOi (Fig. 3) is disposed in a horizontal- plane extending between in the rollers 30a and 3Ob as well as between outlet rollers 30c and 30d. Pushing means P on board feeding means B is actuated whereupon pushing surface lOn moves topmost board 10i in the direction of arrow 10s (Fig. 2). Translation of pushing surface lOn along edge lOv of topmost board lOi also forces topmost board lOi against guide surface lOx. Control means D actuates inlet rollers 30a and 30b and outlet rollers 30c and 30d whereupon when pushing surface lOn moves topmost board lOi into board inlet 20b and topmost board 10i engages inlet rollers 30a and 30b, the board will proceed toward board outlet 20n until it engages outlet rollers 30c and 30d. The first board is fed into frame 20d, until it can be held by both inlet rollers 30a and b and outlet rollers 30c and d. Carriage 40f is then actuated on rail 40c to make the initial cut, thereby indexing all subsequent boards to be fed into frame 20d. The segment of the first board fed into frame 20d which extends between board ripping blade 40p and board outlet 20n is the only discard piece generated in using the system. Once the initial orientation of the first board is made, board feeding means B continues to feed that first board into board inlet 20b for further cutting. It should be noted that upon feeding the first board into board inlet 20b and making the initial cut with board ripping blade 40p as well as shiplap blade 40n, the next cut on the same

board, to be made- by actuating carriage 40h, takes place only after the first board fed into board inlet 20b is further driven such that its leading edge contacts outlet rollers 30c and 30d. Stated differently, no cuts are made unless a board is secured within frame 20d by both inlet rollers 30a and 30b as well as outlet rollers 30c and 30d. As previously described, joining means J in conjunction with control means D tapes a butt joint 20m (Fig. 3) when control means D indexes the butt joint adjacent joining means J by selective operation of board support means S. As a result there is a continuous feed of board to be cut with some scored boards 20 emerging from frame 20d having an additional taped butt joint thereon.

At the completion of a run for a specific job, control means D actuates outlet rollers 30c and 30d independently of inlet rollers 30a and 30b to drive the last piece from frame 20d via outlet 2On. As a result, the trailing segment of the last board remains indexed between inlet rollers 30a and 30b for an immediate start of the next production run. The boards 20 having been scored and driven through board outlet 20n (Fig. 3) are each individually folded into the shape shown in Fig. 7 and placed upon sealing means T. Movable platform 90b is raised until flap 70d is held tightly against the foil backing of panel 70t whereupon carriage 90f is actuated to seal longitudinal joint 70s by applying tape over flap 70d and the foil backing of panel 70t. The platform 90b is then lowered and the duct section is ready for use.

The apparatus A and associated method of the present invention present an improvement in the duct forming arts in that independent of the size of boards being used, no waste is generated after the initial board has been - indexed in the machine. It should be noted, however, that a variation of thickness of board being cut will require a blade change and adjustment of clearances for joining means J as well as board support means S. By virtue of board feeding means B and joining means J, a tall stack of

boards (usually 48) can be continuously fed one at a time for scoring by cutter means C. The modified shiplap cut performed by blade assemblies 40j and 40k provides the structural rigidity of V-groove cuts with the flexibility of the shiplap cut to allow easy connection of branch ducts. The modified shiplap cut further allows the scored boards to be folded into substantially rectangular or square shapes for taping thus obviating the need for overbending into a parallelogram shape during taping as was done in the past. The ability to tape a duct section while in essentially a square to rectangular shape allows the use of a simply constructed sealing means- T. Due to its lightweight construction sealing means T can be employed adjacent frame 20d for taping duct sections remote from the job site or can be used on a job site to seal a stack of boards scored by cutter means C at a remote location. When a job is completed, sealing means T can be easily transported another job site and the process repeated. The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.