US3258948A

US3258948A - Sheet metal forming apparatus

Info

Publication number: US3258948A
Application number: US320731A
Authority: US
Inventors: Sr John I Carlson
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1963-11-01
Filing date: 1963-11-01
Publication date: 1966-07-05
Anticipated expiration: 1983-07-05

Description

July 5, 1966 J. l. CARLSON, SR 3,258,948

SHEET METAL FORMING APPARATUS Filed Nov. 1, 1963 2 Sheets-Sheet, 1

FIGI

y l6 1 H J 6 26 I INVENTOR JOHN I H03 CARLSON,SR.

ATTORNEY y 1966 J. CARLSON, SR 3,258,948

SHEET METAL FORMING APPARATUS Filed Nov. 1, 1963 2 Sheets-Sheet. 2

1 mhhhhhh FIG 4 INVENTOR,

JOHN l. CARLSONSR.

BY I (M7 ATTORNEY United States Patent M 3,258,948 SHEET METAL FORMING APPARATUS John I. Carlson, Sr., New Britain, Conn., assignor to General Electric Company, a corporation of New York Filed Nov. 1, 1963, Ser. No. 320,731 9 Claims. (Cl. 72---57) My invention relates to sheet material forming apparatus, and more particularly to sheet material forming apparatus utilizing elastomeric or rubber-like die members.

The use of elastomeric or rubber-like material as a die member has come into substantial use in connection with sheet metal forming primarily because the use of this material for a die is substantially less expensive than constructing a metal die by conventional metal machining methods. In accordance with prior art elastomeric metal forming techniques, a sheet of metal to be formed is laid on a bed of elastomeric material, and a forming punch is brought down against the metal, forcing it into the bed of elastomeric material and causing portions of the sheet to be folded up around the punch, forming the desired bend or bends.

In order to get satisfactory sharp bends, it has been necessary to provide the body of elastomeric material with grooves in the upper surface thereof, along the intended bendline of the metal, and to place the workpiece on the elastomeric material so that the intended bendline of the workpiece coincides with the grooves provided in the elastomeric material. While it is possible, with such prior art technique, to use a single bed of elastomeric material to form bends in workpieces of different sizes, this requires provision of grooves in the surface of the material at each of the desired bendlines as previously described, and the accurate placement of the workpieces thereon in each case,

Also, in accordance with prior art, if it is desired to use a single bed of elastomeric material to bend workpieces of different sizes, a bed must be provided which is large enough to handle the largest piece to be bent. This adds substantially to the expense of the equipment, and detracts from its efficiency, since it may be only once in a great while that such a large piece is desired to be bent. In addition, the large size of such a bed of elastomeric material makes it inconvenient to Work with smaller size workpieces.

It is an object of the present invention to provide metal forming apparatus of the elastomeric bed type, which does not require the provision of pre-cut grooves in the surface of the elastomeric material and corresponding placement of the workpiece on the elastomeric material.

It is another object of the invention to provide metal forming apparatus of the elastomeric bed type which has a high degree of flexibility and is capable of handling sheet metal workpieces of a variety of sizes without requiring substantial time and labor in setting up the equipment or in changing from one size to another.

It is another object of the invention to provide metal forming apparatus of the elastomeric bed type which is comparatively inexpensive and utilizes only a relatively small amount of elastomeric material.

In accordance with the invention in one form, sheet metal forming apparatus is provided including a die member comprising a bed or body of elastomeric material which is contained within a heavy, generally tray-shaped, metallic support or casing providing a bottom wall and upstanding side walls and an open top wall. The casing is supported for limited rocking or pivotal movement about an axis extending parallel to the intended bendline.

3,258,948 Patented July 5, 1966 The die member comprising the casing and the bed of elastomeric material is normally supported in a substantially horizontal position by spring means, whereby when a punch member is brought down against a workpiece laid on top of the elastomeric material, the workpiece is gripped between the punch and the upper surface of the elastomeric material as the die member is rocked about its pivot, compressing the spring. A portion of the workpiece is bent a small amount about a corner of the punch member as the die member rocks under the downward pressure of the punch. Continued downward movement of the punch member after the die member reaches the limit of its rocking movement completes the bending action by forcing the workpiece a short distance further into the elastomeric material, causing the elastomeric material to bulge slightly around the edge of the punch, folding the bent portion of the workpiece around the edge of the punch.

In accordance with the invention in another form, a pair or elastomeric die bed assemblies are supported in spaced apart co-planar relation, whereby a workpiece may be laid so as to expand partially onto each die bed assembly, and a pair of punch members are brought down simultaneously thereby forming two bends at once.

In accordance with another aspect of the invention, means is provided for moving the two elastomeric die bed assemblies toward and away from each other, together with their corresponding punch members, whereby the distance between the two bends to be made simultaneously may be selectively adjusted within a predetermined range.

The invention will be more completely understood from the following detailed description, and its scope will be pointed out in the appended claims.

In the drawings:

FIGURE 1 is an elevation view of one embodiment of the invention partially incross-section, showing the die members in their normal positions;

FIGURE 2 is an elevation view similar to FIGURE 1, showing the die members in their actuated or depressed position;

FIGURE 3 is a plan view of the apparatus of FIG- URES 1 and 2, and

FIGURE 4 is anelevational view of another embodia ment of the invention.

FIGURE 1 illustrates a metal bending apparatus in accordance with one embodiment of this invention wherein a pair of die assemblies, generally indicated by 1 and 2 are mounted upon a base member 3 for cooperation with vertically

movable punches

4 and 4A carried by a press ram 4B. Each die structure is identical with the other; therefore, only one will be described in detail. Each die structure includes a casing or container having a bottom wall 9 and surrounding, upwardly extending side walls 10 which form .a generally rectangular upwardly opening cavity 11. The cavity 11 is filled with elastomeric material 8. Thus the elastomeric material is effectively confined while leaving the upper or working surface open. The upper surface of the elastomeric material is preferably made to project a small amount, such as 36 above the corresponding surfaces of the adjacent side walls of the casing 6.

Each casing 7 is pivotally mounted on the corresponding support member 6 by means of a pair of

trunnions

20 and 21, which extend through

openings

22 and 23 in the side of the support member 6 and are received in

recesses

24 and 25 in the casing (as best shown in FIGURE 3). The casing 7 is biased to an upper position by means of coil springs 26 which are mounted in recesses 27 provided in the support member 6 and similar recesses 28 provided in casing 7. While the casings 7 are guided by the

trunnions

20, 21, however, the primary bearing surfaces are provided by portions 6A of the

support

6 and 7A of the casing 7.

Downward movement of the

punches

4 and 4A causes them to engage the upper surface of the workpiece 5 and to press it against the upper surface of the elastomeric material 8. Continued downward motion of the punches rocks each of the die assemblies comprising the casings 7 and the elastomeric material about their respective pivotal supports, compressing the springs 26. At the same time, a part bend is formed in the workpiece at each of the

outer corners

29 and 30 of the

punches

4 and 4A. This fixes the position of the workpiece with respect to the punches, so that no lateral shifting can occur as the process continues.

The casings then bottom against the supports 6. The

punches

4 and 4A continue to travel a short distance, however, forcing the workpiece further into the elastomeric material adjacent the corners of the punches, and completing the bending action. In this connection, it should be noted that the elastomeric material bulges slightly along the outer surface of the

corners

29 and 30, as at 31, 32 respectively, thereby assisting in making a sharp bend.

In accordance With the invention, the die members are made horizontally adjustable. For this purpose, each support member 6 is formed with a pair of horizontally extending

slots

12 and 13 which fit about upwardly extending

rails

14 and 15 provided on the base member 3. Each die structure is provided with an outwardly extending threaded shaft 16 which is rotatably attached to the support 6 at one end by means of a bracket 16A and extends through a threaded opening 17 provided in a block 18 mounted on the base member 3. A manually operable handle 19 is attached to the outer end of the threaded shaft 16 to facilitate horizontal movement of the die structure.

While the

corners

29 and 30 of the punch have been shown as being right-angled, it has been found that they may be formed as acute angles, and the upward bulges 31 and 32 of elastomeric material will bend the workpiece 5 at an angle in excess of 90. This may be desirable to allow for the workpiece springing back a small amount after it has been bent. Other modifications of the shape of the punch may also be made, particularly at or near the outer corner portions without affecting the operation of the invention.

At the conclusion of the bending process, the punch 4 is raised and the springs 26 force the casings 7 upwardly to the position shown in FIGURE 1 and the formed Workpiece is removed. It may be noted from FIGURE 3 that the trunnions and 21 and the

bearing surfaces

6A and 7A are spaced from the outer edges of the

punches

4, 4A. With this arrangement, downward movement of the punch 4 causes the tiltable casings 7 to rotate downwardly and slightly outwardly, carrying the elastomeric material 8 with them. Since the upper surface of the elastomeric material 8 is in intimate contact with the workpiece 5, the downward and outward tilting of the casings 7 causes the elastomeric material to exert an outwardly directed force on the workpiece. The outwardly directed force on the workpiece at each side keeps the center of the workpiece taut and prevents any buckling even though there is no support directly under the center portion.

In FIGURE 4, the invention is shown as embodied in metal forming apparatus comprising a pair of punch and die

assemblies

35, 36. Each of the punch and die

assemblies

35, 36 comprises a base support member 37 carrying a pair of guiding posts 38. Since FIGURE 4 is an end elevation view of the assembly, the pair of supporting posts 38 of each

assembly

35, 36 are in alignment, and

therefore only one post of each assembly may be seen in this view.

Slidably supported on the posts 38, is an upper support member 39 having a pair of holes 40 adapted to receive the posts 38. The upper support member 39 also carries a plurality of headed bolts 41, the heads of which are received in generally T-shaped slots 42 in a member 43 which may comprise the vertically movable portion of a press or which may comprise a plate attached to such movable portion.

The base support member 37 carries a die supporting block 43 rigidly attached thereto by suitable means, not shown, which in turn hingedly supports the elastomeric die assembly comprising a rigid tray-like casing 44 containing a block or bed of elastomeric material 45. The

- casing 44 is normally held in a substantially horizontal position by means of a relatively heavy compression spring 46. The upper support member 39 carries a punch member 47 adapted to cooperate with the elastomeric material 45.

In accordance with this aspect of the invention, means is provided for adjusting the relative positions of the punch and die

assembly

35 and 36, without disturbing the preset relationship between the punch members 47 and the die members 45. For this purpose, an elongated threaded adjusting rod 50 is provided, which is rotatably journalled in a supporting block 51 midway between the

assemblies

35, 36. The rod 51) has one portion extending through the base support 37 of the punch card and die assembly 36, and an oppositely directed portion extending through the base portion 37 of the punch and die assembly 35. The respective halves of the rod 50 are threaded in opposite directions, so that rotation of the rod 50 in one direction, such as by the wheel 52 having a handle 53, causes the punch and die

assemblies

35, 36 to move toward each other, and in the opposite direction causes them to move away from each other. The adjusting movement of the punch and die

assembly

35, 36 toward and away from each other is facilitated by the slidable mounting of the upper support members 39 in the member 43 by means of headed bolts 41 riding in T-shaped slots 42, as previously described. Comparable slidable guiding means, not shown, is also provided for the base members 37 on their support plate. Following adjustment of the spacing between the punch and die

assemblies

35, 36, the upper support members 39 are fixedly anchored in place by suitable means such as by clamping nuts threaded onto the bolts 41, or by other suitable means, and the base support member 37 is likewise fixedly anchored to its support by suitable means.

While the adjustable die structure shown in FIGURE 4 is shown as used with the preferred form of elastomeric die construction, it will be readily obvious that the aforesaid adjustable die structure may be used with conventional rigidly-supported metal bending dies in place of the elastomeric material 45.

Other modifications of the invention will also occur to those skilled in the art, and I therefore intend by the appended claims to cover all such modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Sheet material forming apparatus comprising:

(a) a support;

(b) a casing having a bottom wall and peripheral upstanding side walls defining a cavity therein;

(c) resilient means supporting said casing on said support;

(d) a body of elastomeric material filling said cavity and having a generally planar surface thereof exposed to receive a workpiece of sheet material thereon;

(e) punch means disposed and arranged to engage said workpiece when on said exposed surface of said body of elastomeric material and to cause pivotal movement of said casing against said resilient support whereby to force said workpiece partially into said body of elastomeric material and to bend a portion of said workpiece around a corner of said punch.

2. For use with metal bending apparatus having a movable punch for forming bends in a workpiece, a die apparatus comprising:

(a) a support;

(b) a rigid casing pivotally supported on said support,

said casing having a bottom and peripheral upstanding side walls defining an open-top recess;

(c) a body of elastomeric material filling said cavity and having a surface thereof exposed at said open p;

(d) stop means carried by said support, and

(e) resilient means supporting said casing in a normal position spaced away from said stop means, whereby a sheet material workpiece may be placed on said exposed surface and pressed by said punch against said body of elastomeric maerial, rotating said casing about said pivotal support and against said stop to form said workpiece around said punch.

3. For use with sheet material bending apparatus including a movable punch for forming bends in a workpiece, a die assembly comprising:

(a) a support;

(b) a casing having a generally planar bottom wall and peripheral upstanding side walls defining an opentop recess;

(c) a body of elastomeric material filling said recess and having a surface portion thereof exposed at said open top;

(d) means supporting said casing on said support for pivotal movement, said casing having the outer portion of one of said side walls formed to provide an elongated pivotal bearing surface extending substantially the same length as the corresponding dimension of said elastomeric body;

(e) stop means carried by said support, and

(f) means resiliently supporting said casing on said support with said exposed surface of said elastomeric body extending substantially in a horizontal plane.

(4. Sheet material bending apparatus comprising:

(a) a support;

(b) a pair of casing members pivotally supported on said support, each of said casing members comprising a generally planar bottom Wall and peripheral upstanding side walls defining an open-top recess;

(c) a body of elastomeric material substantially filling each of said recesses;

(d) means supporting said casings on said support for pivotal movement about parallel axes, said axes extending adjacent the outer edges of each of said casing members respectively;

(e) stop means limiting said pivotal movement of said casings, and

(f) means resiliently supporting each of said casing members with said exposed surface of said elastomeric material extending substantially in a common plane.

5. Sheet material bending apparatus comprising:

(a) a support;

(b) a pair of casing members, each of said casing members comprising a generally planar bottom wall and peripheral upstanding side walls defining an open top recess;

(c) a body of elastomeric material substantially filling each of said recesses;

(e) stop means limiting said pivotal movement of said casings;

(f) means resiliently supporting each of said casing members with said exposed surfaces of said bodies 6. of elastomeric material extending substantially in a common plane;

(g) and means for adjustably positioning said casing members closer or farther away from each other whereby to accommodate workpieces of varying sizes.

6. Sheet material bending apparatus as set forth in claim 5 wherein said adjusting means comprises a shaft journalled for rotation on said support substantially midway between said punch-and-die assemblies and having a first portion thereof in threaded relation with a first one of said assemblies and a second portion thereof in threaded relation with the other of said assemblies, said portions being threaded in opposite directions, and means for rotating said shaft to adjustably position said assemblies.

7. Sheet material bending apparatus comprising:

(a) a pair of spaced supports;

(b) a casing member pivotally mounted on each of said supports, said casing comprising a generally planar bottom wall and peripheral upstanding side Walls defining an open-top cavity;

(c) a body of elastomeric material filling each of said cavities and having a generally planar surface thereof exposed at said open top;

(d) resilient means supporting each of said casing members with said exposed surface of said elastomeric material extending in a substantially common plane;

(e) the pivotal axes of said casings on said supports extending parallel to each other and adjacent the outer edges of said casings, and

(f) means for adjustably positioning said supports closer to or farther away from each other.

8. Sheet material bending apparatus comprising:

(a) a support;

(b) a pair of punch and die assemblies supported on said support, each of said punch and die assemblies comprising a base plate and at least one vertically extending guide post supported on said base plate, a punch supporting member disposed in vertically spaced relation over each of said base plates and having a hole therein adapted to receive said guide post;

(c) punch means carried by each of said punch support members and having a predetermined relationship to said die member;

(d) a casing member pivotally mounted on each of said base plates, said casing comprising a generally planar bottom wall and peripheral upstanding side walls defining an open-top cavity;

(e) a body of elastomeric material filling each of said cavities;

(f) resilient means supporting each of said casing members;

(g) the pivotal axes of said casings on said base plates extending parallel to each other and adjacent the outer edges of said casings, and

(h) means for moving at least one of said punch and die assemblies with respect to the other of said punch and die assemblies on said support without disturbing said predetermined relationship of each of said punches with respect to the corresponding die member.

9. Sheet material bending apparatus comprising:

(a) a support;

(e) a. body of elastomeric material filling each of said cavities;

(f) resilient means supporting each of said casing members;

(h) means for simultaneously moving said pair of punch and die assemblies selectively toward and away from each other at substantially equal rates of speed Without disturbing said predetermined relationship of each of said punches with respect to the corresponding die member to selectively vary 2 the distance between said bends While maintaining symmetrical relationship of said bends with respect to a predetermined center line.

References Cited by the Examiner UNITED STATES PATENTS 1,268,360 6/1918 Kimball.

2,362,006 11/1944 Herzog 723 96 2,390,803 12/1945 Marschner 724OO 2,443,596 6/1948 Cahill 72396 3,045,327 7/1962 Clarke et a1.

FOREIGN PATENTS 690,007 4/ 1953 Great Britain.

OTHER REFERENCES Modern Metals: September 1960, vol. XVI, No. 8, page 56.

CHARLES W. LANHAM, Primary Examiner.

R. D. GREFE, Assistant Examiner.

Claims

1. SHEET MATERIAL FORMING APPARATUS COMPRISING: (A) A SUPPORT; (B) A CASING HAVING A BOTTOM WALL AND PERIPHERAL UPSTANDING SIDE WALLS DEFINING A CAVITY THEREIN; (C) RESILIENT MEANS SUPPORTING SAID CASING ON SAID SUPPORT; (D) A BODY OF ELASTOMERIC MATERIAL FILLING SAID CAVITY AND HAVING A GENERALLY PLANAR SURFACE THEREOF EXPOSIED TO RECEIVE A WORKPIECE OF SHEET MATERIAL THEREON; (E) PUNCH MEANS DISPOSED ARE ARRANGED TO ENGAGE SAID WORKPIECE WHEN ON SAID EXPOSED SURFACE OF SAID BODY OF ELASTOMERIC MATERIAL AND TO CAUSE PIVOTAL MOVEMENT OF SAID CASING AGAINST SAID RESILIENT SUPPORT WHEREBY TO FORCE SAID WORKPIECE PARTIALLY INTO SAID BODY OF ELASTOMERIC MATERIAL AND TO BEND A PORTION OF SAID WORKPIECE AROUND A CORNER OF SAID PUNCH.