US3034559A - Dies for bending sheet metal - Google Patents

Description

May 15, 1962 D. M. SLATER 3,034,559

DIES FOR BENDING SHEET METAL Filed flab. 25, 1960 s Sheets-Sheet 1 INVENTOR 5 May 15, 1962 D. M. SLATER 3,

DIES FOR BENDING SHEET METAL Filed Feb. 25, 1960 v 3 Sheets-Sheet 2 lNVENTO RI flax/gm! 12 7/2 32 5; M42

ATI'OIRNEY May 15, 1962 D. M. SLATER 3,034,559

DIES FOR BENDING SHEET METAL Filed Feb. 25, 1960 3 Sheets-Sheet 3 17/5 I \j INVENTORZ fax/ ak AZ JZ/FE? 69 United States Patent 3,034,559 DIES FOR BENDING SHEET METAL Douglas M. Slater, Nashville, Tenn., assignor to John W. McDougall Company, Inc., Nashville, Tenn., a corporation of Tennessee Filed Feb. 23, 1969, Ser. No. 10,408 13 Claims. (Cl. 153-21) This invention relates to dies for bending sheet met-a1 and more particularly to dies for forming multiple deep bends in sheet metal to make various types of slip locks for duct work.

Heretofore, the manufacture of slip locks of the 8- type for heating, ventilating and air 'conditioning duct work, has required six or seven different bending operations on conventional sheet metal bending machines. Moreover, such bending operations require a high degree of skill and care in order to bend the metal according to specified dimensions.

It is therefore an object of this invention to provide special sets of dies for forming the slip looks from a flat sheet of metal in two bending operations, which will require a minimum of skill on the part of the die operator and yet obtain a high degree of accuracy and uniformity in the finished slip locks.

Another object of this invention is to provide sets of dies which may be incorporated in a conventional press brake.

Another object of this invention is to provide -a bending set of dies and a flattening set of dies, both of which may be incorporated in the same press brake to carry out their individual functions simultaneously on different sheets of metal.

A further object of this invention is to provide a set of bending dies and a set of flattening dies which may be adapted for forming at least four types of slip locks.

Another object of this invention is to provide sets of dies for forming slip locks of various dimensions.

Another object of this invention is to provide sets of dies for forming multiple deep bends in sheet metal with a minimum of travel and without danger of tearing the metal at their bend points.

Further objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings, wherein:

FIG. 1 is an end elevation of a press brake incorpm rating the bending dies made in accordance with this invention with the upper die in raised inoperative position;

FIG. 2 is an enlarged sectional elevation of the bending dies of FIG. 1 in operative position;

FIG. 3 is an end view of a bent piece of sheet metal formed by the dies of FIGS. 1 and 2;

FIG. 4 is an end elevation of the flattening dies made in accordance with this invention in various operative positions;

FIG. 5 is a sectional elevation of a 1-inch standing S-bar slip lock formed from dies of FIG. 4, and in operative position locking the adjacent ends of connecting ducts;

IG. 6 is a sectional elevation of a modification of the bending dies with the upper die in raised position;

FIG. 7 is an end view of a bent piece of sheet metal formed by the dies of FIG. 6;

FIG. 8 is a view similar to FIG. 4, disclosing the flattening dies operating upon the bent piece of sheet metal disclosed in FIG. 7;

FIG. 9 is a viewsimilar to FIG. 5, disclosing a 1 /2- inch standing S-b-ar slip lock;

FIG. 10 is a view similar to FIG. 9, disclosing a 1 /2- inch reinforced standing S-bar slip lock;

FIG. 11 is an end elevation of another modified form of the bending dies;

FIG. 12 is an end view of a piece of bent sheet metal formed by the dies of FIG. 11;

FIG. 13 is an end elevation of the flattening dies preparatory to operation upon the bent piece of sheet metal disclosed in FIG. 12;

FIG. 14 is a view similar to FIGS. 5, 9, and 10, disclosing a fiat S slip lock.

Referring now to the drawings in more detail, FIG. 1 discloses a conventional press brake 20 having a vertically reciprocable upper head 21 and a lower stationary die support 22. Removably fixed in the stationary support 22 is a first or lower bending die 23 having a top face of novel configuration. Removably fixed and depending from the upper head 21 is the second or upper bending die 24 having a bottom face of a complementary configuration adapted to mate with the face of the lower die 23 when said upper head 21 has been reciprocated to its lowest position. As best disclosed in FIG. 1, a piece of sheet metal 25, which is to be bent into the desired shape, is placed in a substantially horizontal position between the dies when the upper die 24 is in raised, inoperative position. The rear edge of the sheet metal 25 rests against an upright abutment bar 26 fixed to the frame of the press brake 20 in adjustable spaced relation with the dies 23 and 24.

The top face of the lower bending die 23 comprises an upstanding V-shaped projection 30 flanked by a shallow channel-shaped recess 31 and a shallow V-shaped recess 32. The V-shaped projection 30 has a plane side face 33 which is parallel to the direction of movement of the upper die 24, which is preferably vertical as disclosed in the drawings. The other side face 34 of the projection 30 is likewise plane, but slopes at a substantial acute angle downward and away from the vertical face 33. The side faces 33 and 34 are joined by a gradually rounded portion 35 which forms the upper extremity or tip of the projection 30. The channel-shaped recess 31 has a short side wall 36 which is likewise parallel to the direction of movement of the upper die 24, or preferably vertical. The recess 31 has a sloping plane bottom 37 which forms an obtuse angle with the vertical face 33. The vertical face 33 forms the common side of the projection 30 and the recess 31. The V-shaped recess 32 likewise has a vertical side wall 38 of substantially the same height as the side wall 36. The recess 32 likewise shares a common side face or wall 34 with the projection 30, and has a rounded bottom portion or valley 39. The upper edge of the wall 36 is rounded in -a reverse curve 40 which terminates in a sloping plane surface 41, preferably at an angle of approximately 45 to the vertical. In like manner, the top of the wall 38 forms a rounded portion 42 which terminates in a downwardly sloping plane surface 43 at substantially the same angle of 45 to the vertical. A portion of the bottom 37 adjacent the vertical wall 36 in the recess 31 is provided with a threaded opening 44, fora purpose to be described later.

The upper bending die 24 is provided with a V-shaped recess 50 flanked by projections 51 and 52, having common sides 53 and 54 and a rounded connecting portion 55 of the same dimensions and configuration as their mating counterparts 30, 31, 32, 33, 34, and 35 in the lower stationary die 23. The fiat end surface 57 of the projection 51 is of the same slope as and adapted to mate with the bottom 37 of the recess 31. Moreover, the projection 52 has a rounded tip 59 of the same configuration as the bottom portion 39 of the recess 32. The front face 53 of the upper die 24 is a plane vertical surface adapted to mate with the vertical wall 38 of the recess 32 when the dies 23 and 24 engage. The rear wall 56 of the die 24 is recessed at 60 and provided with a threaded opening 61.

In accordance with the specifications of the ASI-IVE (American Society of Heating and Ventilating Engineers), certain types of S-type slip locks have upstanding reinforcing ribs. These ribs are generally standardized at a he ght of either 1 inch or 1% inches. In order to make the bending dies 23 and 24 adaptable to produce the reinforcing ribs of either height, insert blocks 62 and 63 are provided to be alternately employed with the upper die 24 or the lower die 23, respectively, in order to vary the effective height of the reinforcing rib.

When it is desired to produce an S-type Slip lock having a 1 inch reinforcing rib, the insert block 63 is placed along the bottom 37 of the recess 31 abutting the vertical wall 36 and secured in place by means of a screw 64 inserted through the aligned threaded openings 65 and 44. The insert block 63 is provided with a front vertical face 66 which reduces the effective width of the recess 31 to the same configuration as the projection 51 of the upper die 24, as best disclosed in FIGS. 1 and 2.

In the arrangement disclosed in FIG. 2, the insert block 62 is left out of the recess 60 in order for the projection 51 to mate with the recess 31 and bend the sheet metal 25 therebetween into a similar shape. In this particular modification, the length of the sloping end 57 and the length of the bottom portion 37 between the faces 33 and 66 are each about one inch, with a tolerance of about 0.050 inch to permit the sheet metal 25 to fit between the mating surfaces when the dies are engaged. By operating the'movable head 21 to thrust the die 24 downward to engage the die 23, including the insert block 63, the piece of sheet metal 25 will be bent into the shape 70 disclosed in FIG. 3. The bent shape 70 forms an pen S-shaped portion having substantially parallel legs 1 and 72 connected at opposite ends by an angular leg 73, and a reinforcing rib portion having a pair of legs 74 and 75 connected by a bent portion 76.

When it is desired to produce a slip lock having a 1 /2 inch reinforcing rib, the insert block 63 is removed and the insert block 62 is placed in the recess 60 by appropriate means such as a screw 68 inserted through the aligned threaded openings 69 and 61, as best disclosed in FIG. 6. Since the length of the bottom 37 of the recess 31 between its side walls 33 and 36 is preferably about 1 /2 inches and the length of the bottom of the block 62 is about /2 inch, the projection 51 and the insert block 62 are adapted to fit snugly within the recess 31 to form a standing reinforcing rib of 1 /2 inches.

A second set of flattening dies 8t and 81, as best disclosed in FIG. 4, are adapted to be fixed to the stationary support 22 and the upper movable head 21 of a press brake 20 in the same manner as the first set of bending dies 23 and 24. The dies 80 and 81 may be supported in a separate press brake 20 from the dies 23 and 24 or they may be fixed end to end with the dies 23 and 24 in the same members 22 and 21 of the press brake 20. The lower flattening die 89 is stationarily mounted in the sup-. porting member 22 and is provided with a V-shaped recess 82 having faces 83 and 84 intersecting each other at substantially a right angle. The face 83 is adapted to form a more acute angle Wtih the vertical than the face 84. The upper edge of the face 84 terminates in a slight projection 85 employed to produce a slight bend or crimp in the leg 71 of the shape 70 when compressed by the upper die '81. The face 83 of the recess 82 may be provided with various types of removable stop brackets 86 having an abutment 87 to receive the bent portion 76 of the metal shape 70, as disclosed in FIG. 4. The stop bracket 86 may be made of resilient material in order that that it may be clamped over the die 80 as disclosed in FIGS. 4 and 8.

The upper flattening die 81 is adapted to reciprocate vertically into an out of engagement with the lower die 80. The upper die 81 comprises a V-shaped projection having faces 90 and 91 intersecting at substantially a right angle and having the same slopes respectively as the faces 83 and 84 in order that the die 81 will mate with the die 80. Formed in the face 90 adjacent the tip 92 of the upper die 81 is a rectangular shaped notch 93, interseecting the face 90 by rounded portion 94. The purpose of the notch 93 is best illustrated in FIG. 8 where the leg 75 is sufliciently short that it will not be engaged by the tip 92 upon descent of the upper die 81.

The product resulting from the operation disclosed in FIG. 4 upon the bent metal shape is disclosed in FIG. 5 as a 1-inch standing S-bar slip lock 100 locking the adjacent ends of two ducts 10 1 and 102. The open end of the duct 101 slips between the legs 71 and 73, white the open end of the duct 102 slips between the legs 72 and 73 and are held together by the tension in the legs created by the flattening dies 80 and 81. The upstanding reinforcing rib 105 is formed by the legs 74 and squeezed flat against each other between the respective mating faces 83 and 90 of the flattening dies and 81. A slight bend or crimp 106 appears in the leg 71 in exaggerated form in FIG. 5 to create a better seal between the slip lock 100 and the duct 101.. As previously mentioned, such a crimp 106 is produced by virtue of the projection in the face 84 of the lower flattening die 80.

As previously mentioned, FIG 6 discloses the modification in which the insert block 63 has been removed from the die 23 and the insert block 62 has been inserted into the recess 60 of the upper bending die 24 in order to produce a 1 /2 inch standing S-bar slip lock. The bent shape 70 formed by the modified arrangement of the dies 23 and 24 disclosed in FIG. 6, is disclosed in FIG. 7 as having substantially the same configuration as the bent shape 70 disclosed in FIG. 3, except that the leg 74 is /2 inch longer than the leg 74. The lengths of the legs 75 and 75 may be determined by lateral adjustment of the abutment bar 26.

The operation of the flattening dies 80 and 81 upon the bent shape 70 is disclosed in FIG. 8, where the tip 92 of the die 81 descends past the free end of the leg 75 which is caught by the upper side of the notch 94 to start the bending operation. Otherwise, if the notch 93 were not provided, the face would engage the free end of the leg 75 and the force of the descending die 81 would be substantially transmitted longitudinally, instead of transversely, of the leg 75 The product of the operation of the flatening dies 80 and 81 in FIG. 8 is disclosed as a 1 /2 inch standing S-bar slip lock 190 in FIG. 9. Besides the reinforcing rib 165 being /2 inch longer than the rib 105, the function of the slip look disclosed in FIG. 9, is substantially the same as that disclosed in FIG. 5.

Where additional reinforcing is required in the rib a reinforcing bar 110, as disclosed in dashed lines in FIG. 8, may be laid flat on the leg 74 in the bent shape 70 before before it is flattened by the dies 80 and 81. The resulting product 106, a 1 /2 inch reinforced standing S-bar slip lock is disclosed in FIG. 10.

If desired, the bending dies 23 and 24 and the flattening dies 80 and 81 may be employed to form a simple flat S-slip -lock without any reinforcing rib, as best disclosed in FIGS. 1l14. In this modification the abutment bar 26 may be switched to the other side of the bending dies 23 and 24, or the dies may be reversed, to obtain the ar rangement disclosed in FIG. 11. 'Neither of the insert blocks 62 or 63 are required since no reinforcing rib is to be formed. When the upper bending die 24 descends upon the sheet metal 25, the resulting product is a substantially open S-type bent shape disclosed in FIG. 12 having parallel legs 171 and 172 connected at opposite ends by the diagonal leg 173. The bent shape 170 is then inserted in the lower flattening die 80, as disclosed in FIG. 13, for flattening by the upper die 81. In this operation, the notch 93 has no function and the stop bracket 86 is removed. The resulting product, a flat S-slip lock 200, is disclosed in FIG. 14 locking the adjacent ends of the ducts 101 and 102.

The above invention therefore provides a method and apparatus for rapidly bending sheet metal in only two steps to form S-type slip locks. ioreover, the invention contemplates the employment of only two sets of dies, each set having a novel configuration, and both sets of dies are adapted to be employed in the same conventional press brake, if desired. The dies are so designed that they can operate quickly and smoothly to form uniform bends in sheet metal with a minimum of travel of the metal relative to the die faces. Moreover, the construction of the dies is such that the travel is equally divided on both sides of the tip 35 of the projection 30 on the bending die 23.

-Deep forming of the bends in the sheet metal is also facilitated by providing the shallow recesses 31 and 32 on opposite sides of the projection 30 so that the maximum height of the walls 36 and 38 is /2 inch as compared to a height of at least 1 7 inches for the projection 30. Rounding off the edges 40 and 42 and sloping the face portions 41 and 43 also provide smoother operation of the dies 23 and 24 in forming the deep bends in the shapes 7%), 70 and 170.

The invention is also adapted for versatility in forming S-type slip locks of various specified designs and dimensions by providing such accessories as the insert blocks 62 and 63 and by providing for an adjustable abutment bar 26.

It will be apparent to those skilled in the art that various changes may be made in the invention, without departing from the spirit and scope thereof, and therefore the invention is not limited by that which is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is:

1. An apparatus for forming an S-type slip lock comprising a pair of mating dies, means for relatively moving said dies towards engagement and away from each other, one of said dies comprising a V-shaped projection having a first face parallel to the direction of relative movement, said projection having a second face sloping away from said first face and terminating in a shallow recess, said recess having a face opposing said second face and parallel to said first face, said other die having a complementary face adapted to engage said one die to form an S-shaped bend in sheet metal, and means for flattening said S-shaped bend.

2. The invention according to claim 1 in which said recess is V-shaped and said V-shaped projection extends substantially beyond the opposite face of said recess towards said other die.

3. An apparatus for forming an S-type slip lock comprising a pair of mating dies, means for relatively mow'ng said dies towards engagement and away from each other, one of said dies comprising a V-shaped projection having a first face parallel to the direction of relative movement, said projection having a second face sloping away from said first face and terminating in a shallow V-shaped recess, the outer extremity of said projection forminga rounded surface connecting said first and second faces, said second face forming one wall of said shallow recess, said recess having an opposite wall parallel to the first face of said projection, said projection extending substantially beyond the opposite Wall of said recess towards the other die, a substantially channel-shaped recess formed in said one die adjacent said projection, said first face forming one wall of said channel-shaped recess, the opposite wall of said channel-shaped recess being parallel to and substantially shallower than said first face, the bottom of said channel-shaped recess forming an obtuse angle with the first face of said projection, said other die having complementary faces adapted to engage said one die to form open bends in sheet metal in accordance with the configuration of said dies, and means for flattening said bends.

4. The invention according to claim 3 in which the outer edges of said opposite walls of said V-shaped and 6 channel-shaped recesses form rounded portions which terminate in plane surfaces sloping away from said projection and said other die.

5. The invention according to claim 3 in which said means for flattening said bends comprises a second set of dies, one of said dies comprising a V-shaped recess and the other of said second set of dies comprising a mating V-shaped projection having a notch formed in one face thereof spaced proximate to the tip of said projection.

6. The invention according to claim 3 in which means are provided for varying the width of said channel-shaped recess and the mating face of said other die. 7. The invention according to claim 4 in which the opposite walls of said recesses are substantially equal in height and said terminating plane surfaces slope at substantially 45 angles to the direction of relative movement of the dies.

8. The invention according to claim 7 in which the height of the first face of said projection is at least twice the height of either opposite wall of said recesses.

9. The invention according to claim 1 in which abutment means are provided adjacent the dies to engage the edge of sheet metal inserted between the dies.

10. An apparatus for forming an S-slip lock comprising first and second sets of dies, each set comprising a pair of dies adapted to be moved relatively toward engagement with and away from each other, one of said dies in said first set comprising adjacent first and second projections, said first projection extending substantially beyond said second projection, each projection having a plane corresponding side susbtantially parallel to the direction of relative movement of the dies in said first set, the other side of said first projection forming a plane surface sloping between and connecting said corresponding sides to form a recess between said projections, said one die having another surface adjacent the parallel side of said first projection forming an obtuse angle with said parallel side, said other die in said first set having complementary surfaces adapted to engage said one die in said first set, said second set of dies comprising a first die having a V-shaped recess and a second die having a V-shaped projection adapted to mate with said recess, said V-shaped projection having a notch formed in one face thereof spaced proximate to the tip of said projection.

11. An apparatus for forming an S-slip lock comprising a set of bending dies and a set of flattening dies, each set comprising first and second complementary mating dies, means for relatively moving said dies in each set towards engagement and away from each other, said first bending die comprising a V-shaped projection having a first face parallel to the direction of relative movement, said projection having a second face sloping away from said first face and said second bending die, a V-shaped recess formed in said first bending die, said second face forming one wall of said V-shaped recess, said recess having an opposite wall parallel to said first face, a channelshaped recess formed in said first bending die, said first face forming one wall of said channel-shaped recess, said channel-shaped recess having an opposite wall parallel to said first face, the bottom of said channel-shaped recess being substantially fiat and forming an obtuse angle with the first face of said projection, said projection extending substantially beyond the opposite walls of said recesses towards said second bending die and having a rounded surface connecting said first and second faces, the opposite walls of said recesses being of substantially equal height and terminating in rounded portions which slope away from said projection and said second bending die at substantially 45 angles to the direction of relative movement of the bending dies, said second bending die comprising a V-shaped recess of the same configuration as the projection on said first die and having projections of substantially the same configuration as the recesses in said first die to form open bends in sheet metal having the configuration of the said bending dies, said first flattening die comprising a V-shaped recess, the Walls of which are substantially normal to each other, said second flattening die comprising a V-shaped projection of the same configuration as the recess in the said first flattening die, said second flattening die having a notch formed in one face thereof spaced proximate to the tip of said projection for engaging the upper edge of a piece of sheet metal bent by said bending dies and located directly in the path of said notch.

12. The invention according to claim 11 in which the wall of said V-shaped recess in said first flattening die which mates with said un-notohed surface of the projection in said second flattening die has a projection 'at its 'outer extremity for crimping a portion of said sheet metal.

13. The invention according to claim 11 in which detachable stop means are provided to fit over said first flatening die to receive a bent portion of sheet metal to be flattened between the notched face of the projection of said second flattening die and the mating face of said first flattening die.

References Cited in the file of this patent UNITED STATES PATENTS 2,847,052 Hardrnan Aug. 12, 1958 2,847,053 Hardman Aug. 12, 1958 FOREIGN PATENTS 328,890 Great Britain May 8, 1930 642,340 Great Britain Aug. 30, 1950

Images