US2967559A - Trimming and flanging die - Google Patents

Description

Jan. 10; 1961 Filed Feb. 20, 1958 G. D. GARRISON TRIMMING AND FLANGING DIE 5 SheetsSheet 1 /nver for G/enn D. Gaff/50f) Afforney Jan. 10, 1961 e. D. GARRISON TRIMMING AND FLANGING DIE 5 Sheets-Sheet 2 flll'l Filed Feb. 20, 1958 Jan. 10, 1961 G. D. GARRISON TRIMMING AND FLANGING DIE Filed Feb. 20, 1958 5 Sheets-Sheet 3 G/erm 0. Garrison Jan. 10, 1961 G. D. GARRISON TRIMMING AND FLANGING DIE 5 Sheets-Sheet 4 Filed Feb. 20, 1958 /0 van /or G/enn 0. Garrison 'iZ /3' M /n ven for Jan. 10, 1961 Filed Feb. 20,. 1958 /n ven for G/enn D. Gar/[son Unite States Patent TRIMMING AND FLANGING DIE Glenn D. Garrison, 320 Hall St. SW., Grand Rapids, Mich.

Filed Feb. 20, 1958, Ser. No. 716,351

4 Claims. (Cl. 153-2) This invention relates to the construction of dies designed to perform a certain type of operation on sheet metal. In the machines and appliances encountered daily in the lives of everyone, many examples are found of sheet metal panels with flanges extending around most of the periphery. These flanges are often quite deep, and are used either for appearance, added structural rigidity, or a combination of both. The panels are often of quite substantial size, as in the case of the door of a refrigerator, and the depth of the peripheral flanges provides space for accommodating insulation and a variety of interior mechanism, as well as adding an appearance of bulk and solidity which seems to be desirable.

When the flanges are of considerable depth, it becomes diflicult to form them completely by the so-called deep draw procedure without a very expensive and costly sequence of die operations. This procedure produces a continuous flange by a stretching operation similar to that which results if a mans fist were forced into a ring which had been covered by a rubber diaphragm. An excessive amount of such stretching results in tearing of the metal, with the net result of imposing a limitation on the extent of the draw which is possible in a single operation. The cost of draw dies reaches into many thousands of dollars, and due respect for economy requires that the number of them be limited insofar as possible. it should be pointed out also that an extended sequence of draw dies results in a very expensive commitment of 7 press equipment and manual operations which further disturbs the cost.

To minimize the extent of the deep-draw operation, it is standard practice to utilize this procedure to form only a portion of the peripheral flanges, leaving aconsiderable strip of material extending laterally from the flange to be later bent down into co-planar relationship to form a continuation of the drawn flange. This practice is very simple along a straight line, but results in some flow of metal when an attempt is made to continue it around curved sections. Some small deviation from a straight line can be tolerated without excessive distortion, but anything approaching a sharp corner will result in excessive wrinkling of the lateral extension as it is bent down into its final position. This problem at the corners requires that a portion of the corners be cut away so that the amount of bent-down material is so small that wrinkling does not take place. This results in a discontinuity of the flanges at the corners, which may be remedied later by welding or some similar operation if structural integrity or appearance is of prime importance.

A fairly standard procedure for trimming the laterallyextended shelf before bending it down into final position, and for the subsequent bending operation, is in general use. The trimmed outline of the laterally-extending portion (which may be conveniently referred to as a shelf), is defined by a frame-like arrangement of fixed shearing sections mounted on a lower part of a die, with a set of mating shearing members mounted on an upper part ice of the die in position to shear the shelf edge onthe inside of the fixed shearing structure. The construction of the moveable upper shearing members is such that it substantially extends over the full surface of the trimmed shelf so that continued downward movement of the upper part of the die results in ironing the shelf into a continuation of the existing drawn portion of the flange.

The width of the shelf defines the thickness of the upper shearing member, which is normally substantial enough so that structural strength and rigidity is no problem. At the corners, however, where the shelf width must be minimized to avoid wrinkling, the condition is entirely different. Insufficient space exists for a conventional combined shearing and ironing member of adequate strength. This invention provides a die construction directed primarily toward the solution of this problem. The principle of operation involved in this invention centers in the shearing of the corner areas during the trimming operation on the outside of the lower shearing members rather than on the inside as previously outlined. The lower shearing members are caused to retract preferably downwardly away from the shearing plane after the shearing action has taken place. A lateral shifting is also a possible form of retraction. This movement permits the subsequent engagement of an ironing member of substantial size and without interference which will displace the small shelf at the corner into a continuation of the drawn flange. The use of dies embodying this invention has the effect of combining two operations into one, with the net result of lowering both the die cost and the associated manual operations. The several features of the invention will be discussed in further detail through an analysis of the particular embodiments illustrated in the accompanying drawings. In the drawings:

Figure 1 presents a plan view of the corner area of a die constructed according to the preferred form of the invention.

Figure 2 is a perspective view on an enlarged scale of the same area as that shown in Figure 1.

Figure 3 is a section on the plane 3-3 of Figure 1.

Figure 4 is a plan view of a work piece following the deep draw operation, and in the condition in which it is placed on the die illustrated in the drawings for further processing.

Figure 5 illustrates the completed form of the work piece after the shelf has been trimmed and bent down into the continuation of the drawn flange.

Figure 6 presents a view of the plane 6-6 of Figure 4, and is in projection with Figure 4.

Figure 7 presents a section of the plane 7--7 of Figure 5, and is in projection with Figure 5.

Figure 8 presents a fragmentary sectional view of the corner area of the die, on an enlarged scale, with the die in a position which corresponds to the completion of the corner shearing operation to trim the shelf.

Figure 9 presents a plan view of the work piece with sections at the corners of the shelf broken away during the shearing processes at the corners.

Figure 10 presents a section on a vertical plane along the portions of the die corresponding to the straight sides of the work piece which are relatively remote from the corners. The die is in position prior to the commencement of the trimming action on the shelf.

Figure 11 illustrates a schematic view showing the break-away of the scrap portions of the shelf after the trimming operation.

Figure 12 presents a combined view in section on vertical planes at the corner, and also at the sides of the work piece, with the die in position corresponding to the completion of the ironing of the shelf into an extension of the drawn flanges.

Referring first to Figures 4 and 6, the workpiece indicated generally at 20 includes a central relatively planar panel area 21, a peripheral flange 22 extending completely around the piece and formed by the deep draw operation and a laterally-extending shelf 23 which may be considered as substantially parallel to the central portion 21. The purpose of the die construction discussed herein is to transform the work piece from the condition shown in Figures 4 and 6 to that appearing in Figures and 7. The central area 21 has been left undisturbed, but the laterally-extending shelf portions 23 have disappeared to form continuations of the drawn flange 22. Discontinuities are present as indicated at 24 at the corners, which result from the fact that the shelf has been narrowed at the corners to a point where it can be ironed down without wrinkling.

The construction of that part of the die which corresponds to the straight sides of the work pieces is relatively conventional, and is illustrated in'Fi'gure 10. A fixed lower portion of the die is indicated at 25, and is usually supported upon some form of fixed structure mounted on the press. The press is preferably provided with a conventional biasing system indicated at 26 which continually applies a resilient upward force to a limit position. A series of pins, one of which is indicated at 27 in Figure 10, is slideably mounted in the fixed portion 25 of the die and communicates between the biasing mechanism 26 and the intermediate die member 28. The alignment of the die members is maintained through the usual post and bearing arrangement, and need not be discussed here in detail. The upper die member 29 is aligned with respect to the lower die member by the same system, and reciprocates both with respect to the fixed lower die member 25 and with respect to the intermediate die member 28.

A set of fixed shearing bars 30 is mounted on the lower die member 25 by suitable locating pins (not shown) and secured by bolts as indicated at 31 in Figure 10. These bars constitute a framework, the inside edge of which defines the outline of the trimmed shelf 23, the framework being discontinuous at the corners.

A further set of shearing bars indicated at 32 is mounted on the upper die member 29, and is secured in position by the bolts indicated at 33. The outer edge of the lower extremity of the bars 32 cooperates with the shearing edge of the bars 30 to trim the final outline of the shelves 23. As with the bars 30, the bars 32 are discontinuous at the corners. After the shearing operation has been completed, the continued downward movement of the bars 32 results in ironing down the trimmed portion of the shelves 23 into the condition shown in Figure 7. The bottom surface 34 of the bars 32 is given an angle as shown to provide clearance and facilitate the beginning of the bending operation on the material of the shelf so that the bending operation is performed with a greater degree of control following the shearing action. As the stroke of the press proceeds to the final position illustrated at the right side of Figure 12, the block 35, which is mounted on the intermediate die member, 28, moves downwardly somewhat in advance of the lower edge of the bar 34, and the presence of this member further contributes to the control of the shelf during the bending and shearing operations. Downward movement of the intermediate member 28 begins when the top of the post 36 is contacted by the pad 37 of the upper die member 29. The post 36 is fixed with respect to the intermediate die member, and the continued movement of the upper die member 29 after the .contact with the post 36 causes the movement of the intermediate. die member against the action of the biasing system applied through the medium of the pins 27. The work piece is positioned during all of these operations by a pad 38 mounted on suitable structure associated with the lower die section 25.

Referring now to Figures 1, 2, 3, Sand 12, the'strum ture of the die responsible for the formation of the corners of the work piece will now be discussed in detail. A shearing insert 39 is mounted on the intermediate die member 28 at each of the corners, and is held in position preferably by bolts as indicated at 40 in Figure 3. The pad 38 is cut away as shown at 41 to provide clearance for the position of the inserts 39, and the insert is correspondingly bevelled at its upper surface. Downward movement of the upper die member 29 carries with it the upper corner block 42 (secured by the bolts 43 and suitable locating pins not shown) which is formed and positioned so that the edge 44 cooperates with the upper edge of the inserts 39 to trim the shelf 23 to the desired dimensions which will permit the shelf to be bent downward without wrinkling. The position of the cutting edge 44 relative to the point of engagement of the pins 36 and the pads 37 is such that the shearing operation at the corners takes place prior to the initiation of the downward movement of the intermediate die member 28. In fact, the first action of the processing sequence is the shearing out of the scrap pieces at the corners as indicated in Figure 9. The wedge-shaped pieces 45-4-8 are separated from the shelf 23, and fall downwardly and away from the die through the openings 49 at the corners of the lower die structure 25, and are guided in their passage by the chutes 50.

The next step in the sequence of operations involves the engagement of the shearing members discussed in connection with Figure 10. This is also prior to the engagement of the pads 37 with the pins 36 which would cause downward movement of the intermediate die member. This second shearing operation results in the separation of the scrap pieces 51-54 of the configuration shown in Figure 11. Immediately after this second shearing action takes place, the pads 37 will contact the top of the pin 36 to control the downward movement of the intermediate die member 28. As this action progresses, the bearing insert 55 mounted on the upper corner bar 42 withthe bolt 56 comes into engagement with the remaining stub of the shelf 23 which exists after the corner trimming operation has taken place. At approximately the same time, the remainder of the bending operation is initiated at the sides of the work piece. By the time the lower extremely of the bearing insert 55 comes into engagement with the shelf 23, the movement of the intermediate die member will carry with it the upper portion of the shearing inserts 39 so that they will be well out of the way. This condition is shown in the left side of Figure 12. It should be noted that the corner shelf area has been trimmed and bent through the use of structure of very substantial size and rigidity, and through the use of a single press operation. The separation of the scrap pieces of the shelf 23 into the separate corner pieces, followed by the shearing of the side lengths, permits the scrap parts to fall away freely without forming a continuous frame which would complicate the removal of scrap from the die structure.

The details of the die construction at the corners for providing the sequence shearing action is best indicated in Figures 1 and 2. At each corner, blocks 57 and 58 are mounted. The edges 59 and 60 of these blocks, respectively, define the sides of the wedge-shaped pieces 45-48 of Figure 9. The cooperation of the edge 44 with the shearing inserts 39 defines the inner edge of the pieces 45-43. The edges 61 and 62 of the blocks 57 and 53. respectively, serve the dual purpose of cooperating wizh the shearing bar 39, and also Will the shearing bars that trim off the pieces 51-54 shown in Figure 11 from the straight sides of the shelf 23. The blocks 57 and 58 are substantially duplicated at the four corners of the work pieces. and are located in position by conventional pins (not shown) and secured by bolts as shown at 62 and 63.

The particular embodiments of the present invention which have been illustrated and discussed herein are for illustrative purposes only and are not 'to'be'consid'ered as a limitation upon the scope of the appended claims. In these claims, it is my intent to claim the entire invention disclosed herein, except as I am limited by the prior art.

I claim:

1. A trimming and fianging die, said die comprising: a base member having a portion normally fixed with respect thereto for engaging and supporting workpieces, said base member also having fixed interrupted shearing means disposed to establish portions of a substantially continuous trim line, and also having spaced shearing means intersecting said trim line and extending to one side thereof; a movable intermediate die member mounted for limited reciprocation with respect to said base member; biasing means urging said intermediate member away from said base member to a limit position; corner-shearing means mounted on said intermediate die member and disposed to establish portions of said trim line connecting said portions established by said fixed interrupted shearing means; a normally upper die member mounted for reciprocating movement with respect to said base and intermediate die members; first shearing means mounted on said upper die member, said first shearing means being disposed on the same side of said trim line as said intermediate die member corner shearing means to cooperate with said fixed shearing means; second shearing means mounted on said upper die member, said second shearing means being disposed on the opposite side of said trim line from said intermediate die member corner shearing means to cooperate with said corner shearing means and said spaced shearing means to shear out material within the area defined by said corner shearing means and spaced shearing means; bearing means mounted on said upper die member above said intermediate die member corner shearing means between said trim line and said supporting portion; and abutment means operative to cause movement of said intermediate die member with said upper member at a predetermined position in the reciprocating movement of said upper die member, said position being selected to cause shearing action to take place prior to commencement of movement of said intermediate die member.

2. A trimming and fianging die, said die comprising: a base member having a portion normally fixed with respect thereto for engaging and supporting workpieces, said base member also having fixed interrupted shearing means disposed to establish portions of a substantially continuous trim line; a movable intermediate die member mounted for limited reciprocation with respect to said base member; biasing means urging said intermediate member away from said base member to a limit position; corner-shearing means mounted on said intermediate die member and disposed to establish portions of said trim line connecting said portions established by said fixed interrupted shearing means; a normally upper die member mounted for reciprocating movement with respect to said base and intermediate die members; first shearing means mounted on said upper die member, said first shearing means being disposed on the same side of said trim line as said intermediate die member corner shearing means to cooperate with said fixed shearing means; second shearing means mounted on said upper die member, said second shearing means being disposed on the opposite side of said trim line from said intermediate die member corner shearing means to cooperate with said corner shearing means; bearing means mounted on said upper die member above said intermediate die member corner shearing means between said trim line and said supporting portion; and abutment means operative to cause movement of said intermediate die member with said upper member at a predetermined position in the. reciprocating movement of said upper die member, said position being selected to cause shearing action to take place prior to commencement of movement of said intermediate die memher.

3. A trimming and flanging die, said die comprising: a base member having a portion normally fixed with respect thereto for engaging and supporting workpieces, said base member also having fixed interrupted shearing means disposed to establish portions of a substantially continuous trim line; a movable intermediate die member mounted for limited reciprocation with respect to said base member; biasing means urging said intermediate member away from said base member to a limit position; corner-shearing means mounted on said intermediate die member and disposed to establish portions of said trim line connecting said portions established by said fixed interrupted shearing means; a normally upper die member mounted for reciprocating movement with respect to said base and intermediate die members; first shearing means mounted on said upper die member, said first shearing means being disposed on the same side of said trim line as said intermediate die member corner shearing means to cooperate with said fixed shearing means; second shearing means mounted on said upper die member, said second shearing means being disposed on the opposite side of said trim line from said intermediate die member corner shearing means to cooperate with said corner shearing means; bearing means mounted on said upper die member above said intermediate die member corner shearing means between said trim line and said supporting portion; and means operative to cause movement of said intermediate die member with said upper member at a predetermined position in the reciprocating movement of said upper die member.

4. A trimming and flanging die, said die comprising: a base member, said base member having fixed interrupted shearing means disposed to establish portions of a substantially continuous trim line; a movable intermediate die member mounted for limited reciprocation with respect to said base member; biasing means urging said intermediate member away from said base member to a limit position; corner-shearing means mounted on said intermediate die member and disposed to establish portions of said trim line connecting said portions established by said fixed interrupted shearing means; a normally upper die member mounted for reciprocating movement with respect to said base and intermediate die members; first shearing means mounted on said upper die member, said first shearing means being disposed on the same side of said trim line as said intermediate die member corner shearing means to cooperate with said fixed shearing means; second shearing means mounted on said upper die member, said second shearing means being disposed on the opposite side of said trim line from said intermediate die member corner shearing means to cooperate with said corner shearing means; bearing means mounted on said upper die member above said intermediate die member corner shearing means; and means operative to cause movement of'said intermediate die member with said upper member at a predetermined position in the reciprocating movement of said upper die member.

References Cited in the file of this patent UNITED STATES PATENTS 521,858 Higgins June 26, 1894 1,223,849 Berry Apr. 24, 1917 1,932,407 Hothersall Oct. 31, 1933 2,257,965 Koch Oct. 7, 1941

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