US3672194A

US3672194A - Forming and trimming apparatus for hydroform press

Info

Publication number: US3672194A
Application number: US91288A
Authority: US
Inventors: John J Martin
Original assignee: Avco Corp
Current assignee: Avco Corp
Priority date: 1970-11-20
Filing date: 1970-11-20
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27

Abstract

A device having separate shape-forming and trim die portions is incorporated in a hydroform press. A blank sheet is placed over the die portions and a diaphragm is placed over the blank sheet. The diaphragm is pressurized with hydraulic fluid and then only the shape-forming die portions are urged into the flexible die element to shape and trim the element in a single cycle of the machine.

Description

United States Patent Martin [4 1 June 27, 1972 s41 FORMING AND TRIMMING 2,766,711 10/1956 Dever et al. ..72/s7 APPARATUS FOR HYDROFORM PRESS 2,344,743 3/1944 Sm1th, .lr ...72l57 2,859,719 11/1958 Krayb1ll ..72/63 [72] Inventor: John J. Martin, Milford, Conn.

1 Primary Examiner-Richard J. Herbst [73] Asslgnee. Avco Corporation, Stratford, Conn. Atmmey Chafles M Hogan and Gary M. Gm [22] Filed: Nov. 20, 1970 [57] ABSTRACT [21] App1.No.: 91,288

A device having separate shape-forming and trim die portions is incorporated in a hydroform press. A blank sheet is placed U.S. Cl. ..72/55, 72/63 over the die ortions and a diaphragm is placed over the blank [51] lnt.Cl ..B2ld 28/18 sheet. The diaphragm is pressurized with hydraulic fluid and [58] Field of Search ..72/55, 57, 63; 18/19 F, DIG. 19; then only the shape-forming die portions are urged into the 264/313 flexible die element to shape and trim the element in a single cycle of the machine. 56 ited 1 References C 5 Claims, 3 Drawing Figures UNITED STATES PATENTS 2,719,500 10/ 1955 Kraybill ..72/57 l 1 I I mm W 32 8\ f 5 my? INVENTOR. JOHN J. MARTIN ATTORNEYS.

P'A'TE'N'TEDJum m2 SHEET 2 OF 2 INVENTOR JOHN J. MARTIN MUM M. W 7 ATTORNEYS.

FORMING AND TRIMMING APPARATUS F HYDROFORM PRESS The present invention relates to die elements for use with hydroform shape-forming machines.

Several years ago the process of hydroforming was developed to rapidly and efficiently form complex parts. Such a machine generally consists of a rigid male die element which is connected to a hydraulic ram of the hydroform machine. A

7 blank sheet is laid over the rigid die element and a flexible die element that forms one wall of a'chamber is positioned over the blank sheet. The pressure in the pressure chamber is increased to an extremely high level, such as 10,000 p.s.i. with hydraulic fluid. This forces the blank sheet element against the contours of the rigid die element. After this initial pressurization the hydraulic ram in the machine is actuated to displace the rigid die element'along with the-blank sheet into the flexible die element. This greatly increases the stresses in the chamber and causes the blank sheet to conform to the shape of the rigid dieelement. As the rigid die element is pushed into the flexible die element, the flexible die element exerts a lateral pressure locking the blank sheet to the contours of the rigid; die element and distributing the remaining metal uniformly over the entire surface of the die.

This process enables the deep. drawing of many parts in a single operation and, as a, result, has greatly decreased manufacturing costs for the items so formed. However, even with present hydroform machines additional steps are necessary to trim the part so formed.

Therefore it is an object of the present invention to form and trim a blank sheet element in a single cycle of a hydroform machine, while bridging the central portion of the hydraulic ram.

In a machine of the above type the above ends are achieved by an apparatus comprising a rigid shape-forming die displaceable toward a'flexible die of the machine. A trim dieis supported by the machine base at the same level as the shapeforming die for receiving a blank sheet during initial pressurization of the flexible die. As a result, the blank sheet is formed by pressurization of the' flexible die element and trimmed by displacement of the shape-forming die element toward the flexible die element.

The above and other related objects and features-of the present invention will be apparent from a reading of the description of the disclosure shown in the accompanying drawings and the novelty thereof pointed out in the appended claims.

In the drawings: v

FIG. 1 is an elevational view of a hydroform machine utilizing apparatus embodying the present invention;

FIG. 2 is an expanded fragmentary view of a portion of the apparatus shown in FIG. 1;

FIG. 3 is a view taken on lines 3-3 of FIG. 2.

Referring now to FIG. 1 there is shown a hydroform machine with which the present invention is used. The machine comprises a base 12 from which four massive structural support posts 14 extend vertically. An adjustable carriage 16, which can be positioned at varying distances from base 12, is guided on posts 14. Carriage 16 has an integral chamber l8which has a flexible die element, such as a rubber diaphragm 20, positioned over one end. The diaphragm 20 is made of material that can withstand extremely high-pressures, for example, butyl rubber. For protection of the butyl rubber diaphragm 20 there is generally an additional diaphragm 22 positionedover diaphragm 20. A retaining plate 24 is secured to carriage 16 by screws (not shown) to hold the diaphragms 20, 22 in place. 7 ,7

The base of the machine 12 has a hydraulic ram or actuating element 28 which is displaceable upwards toward diaphragm 20; The ram has a central output shaft 30 which includes a actual machines extends upward from base 12 and a suitable provision is made in the apparatus described below to make the shaft 30 inoperative.

The apparatus comprises an outer support ring 38 abutting base 12 and appropriately retained in place. Within the outer ring 38 is a ring 44 which supports the periphery of a base disc 46 positioned over the actuating rods 32. Base disc 46 has an integral circular trim die element 48 which defines the inner diameter of a ringlike finished piece which is to be formed froma blank sheet 50. A peripheral trim die element 52 is supported by outer ring 38 and, defines the outer diameter of the ringlike finished piece.

An annular shape forming die support 51 is received within an annular raceway 54 defined by the outer and inner trim die elements 52 and 48, respectively. Annular shape-forming die elements 56 are secured to the die support 51 by means of screws 58. The shape-forming die elements 56 may be shaped to produce a number of configurations. However, for purposes of illustration the shape-forming-die elements are being used to form shallow recesses 55 around the finished piece which is stacked with other pieces to form a heat exchanger.

The shape-forming die elements 56 interfit with the trim die elements 52 and 48 to define the edges of the finished piece.

The die support 51 is displaceable in raceway 54 towards diaphragm 20 by means of a plurality of displaceable rods 60 abutting the bottom surface of die support 51 and extending through openings 62 in the base disc element 48. The bottom of rods 60 abut a displaceable disc 64 which is positioned underneath the base disc 56 and within the peripheral ring support 44. The bottom surface of displaceable disc 64 abuts the actuating rods 32 extending from machine base 12 As a result of this connection the die support 51. and shape-forming die elements 56 are displaceable in an upward direction in response to the displacement of actuating rods 32. While die elements 48 and 52 remain in place holding stripped waste material from blank sheet 50, the cycle is completed without die element 48 being displaced in an upward direction by the output shaft 30. i

In order to support the central portion of the base disc 48 and guide displaceable disc 64, a plurality of support rods 66 abut the bottom of disc 48 radially inward from the periphery support ring 44. Rods 66 extend through openings 68 in the displaceable disc 64 to abut the upper surface of the machine base 12. v

The finished piece, in addition to having a ringlikeshape, may have a series of irregular perforations around its periphery, as shown in FIGS. 2 and To produce these per forationsa series of perforation trimelements 70, 72 are positioned in corresponding recesses 74, 76 positioned around the circumference of the shape-forming die elements 56, as shown 7 particularly in FIG. 3. The trim element 70 is supported within recess 74 by a pair of pins 78 which extend through suitable openings in the die support 51 to abut the upper surface of the base disc 46. The perforation trim element 72 is supported within recess 76 by a plurality of pins 80'which extend through openings 82, as shown in FIG. 2, to abut the upper surface of base disc 46. The perforation trim elements 70, 72' are positioned by the pins 78, 80 to be maintained at the same level as the trim die elements 52 and 48.

It should be noted in FIG. 3 that the displaceable rods-60 are positioned around the periphery of the die support 5] midway between each of the adjacent perforation trim elements around the circumference of the shape-forming die elements 56.

To form a piece the following operation is used: A blank sheet 50 is placed over the outer and inner trim die elements 52 and 48 and the movable carriage l6 lowered-to position the diaphragm 20 over the blanksheet 50, as shown in FIG. 1. Thepressure in chamber 18 is increased to a very high level so that the blank sheet is forced by diaphragm 20 into the recesses 55 formed in the die elements 56/After this is done the actuating rods 32 are displaced upwards. This causes die elements 56*to be displaced a small amount into the diaphragm 20, as shown in FIG. 2. It should be noted that the trim die elements 52, 48

and also the perforation trim elements 70, 72 remain stationary because they are supported by the base disc 46 or the outer retaining ring 38, both of which are supported on the machine base 12. The resultant relative movement causes the diaphragm 20 to sear off the blank sheet 50 at the junction between the trim die elements and the shape-forming die elements 56. Thus a blank sheet is formed and trimmed in a single cycle of the machine.

It can be seen that the above apparatus is easily installed on a standard hydroform machine and is able to accommodate the actuating rods built into the machine while still maintaining a rigid support of the die elements. The base disc 46 not only is supported at its periphery but is supported directly underneath the central die element 48 to minimize bending stresses produced by the extremely high pressures exerted over the upper surface of the die elements. At the same time rods 66 act as guides for the even displacement of disc 64 to produce a uniform shearing action.

While the above invention has been described in the forming of a ringlike disc element, it is apparent that it can be used with equal advantage to produce other shapes with equal advantage. It is believed that those skilled in the art can employ additional modifications and use the apparatus for other forms without departing from the spirit and scope of the present invention.

Having thus described the invention, what is claimed as novel and desired to be secured by Letters Patent of the United States is:

l. in a forming machine comprising a stationary machine support base, a flexible die element, one side of which is displaceable over a blank sheet placed in said machine, a means for pressurizing the opposite side of said flexible die element, and an actuating means for urging said blank sheet toward said flexible die element after the opposite side of said flexible die element is pressurized, apparatus interposed between said machine base and said blank sheet for forming and trimming it to a ringlike disc with a series of perforations formed therein around its circumference in a single operation of the above machine, said apparatus comprising:

a rigid shape-forming ringlike die displaceable toward said flexible die element by said actuating means, said shapeforming die means defining the ultimate shape and contours of said disc;

trim die means supported by said machine base interfitting with said shape-forming die means to define the inside and outside diameter of said disc;

a series of perforation trim elements received in recesses conforming to the shape of said perforation elements around the periphery of said ringlike die element;

a plurality of perforation trim element support pins extending from the bottom surface of said perforation trim elements through openings in said shape-forming die element to be supported by said machine base;

said shape-forming die and trim die means and perforation trim elements having blank sheet receiving surfaces positioned at generally the same level for initial pressurization of the opposite side of said flexible die element, whereby said contours of said disc are formed by pressurization of said flexible die element and said disc is trimmed and perforated by displacement of said rigid shape-forming die toward said flexible die element.

2. Apparatus as in claim 1 wherein:

said trim die means comprise:

a base disc positioned over said actuating means;

an annular peripheral support ring positioned on said machine base and supporting the periphery of said base disc above said machine base;

an outer retainer ring element extending around the periphery of said base disc and secured to said machine base, outer retainer ring having an upper support surface above the base disc;

a circular trim die element integral with said base disc and defining the inner diameter of said ringlike disc;

an annular trim die element supported by said outer retainer ring element at the same level as said circular trim die element and defining the outer diameter of said ringlike disc;

said shape-forming die means comprises:

an annular shape-forming die element positioned above said base disc and between said trim die elements;

means for connecting said shape-forming elements to said actuating means whereby said shape-forming die element is displaced relative to said trim elements.

3. Apparatus as in claim 1 wherein said actuating means includes a plurality of axially displaceable actuating rods extending from said machine base and in a generally circular pattern, and wherein said shape-forming die connecting means comprises:

a displaceable disc positioned beneath said base disc and within said peripheral support ring, said displaceable disc being supported on its bottom side by said actuating rods;

a plurality of displaceable rods positioned around the periphery of said central disc and extending through holes in said base die to abut the bottom surface of said shapefor'rning die element.

4. Apparatus as in claim I further comprising a plurality of support rods extending through openings in said displaceable disc and abutting the bottom side of said base disc element radially inward of said peripheral support ring.

5. Apparatus as in claim 4 wherein said perforation trim elements are positioned at regularly spaced intervals around the circumference of said shape-forming ringlike die element and said perforation trim element support pins are supported by said base disc and said displaceable rods which abut said shapeforming die element extend through holes formed in said base disc between each of the adjacent perforation-forming elements around the periphery of said shape-forming die element.

Claims

1. In a forming machine comprising a stationary machine support base, a flexible die element, one side of which is displaceable over a blank sheet placed in said machine, a means for pressurizing the opposite side of said flexible die element, and an actuating means for urging said blank sheet toward said flexible die element after the opposite side of said flexible die element is pressurized, apparatus interposed between said machine base and said blank sheet for forming and trimming it to a ringlike disc with a series of perforations formed therein around its circumference in a single operation of the above machine, said apparatus comprising: a rigid shape-forming ringlike die displaceable toward said flexible die element by said actuating means, said shapeforming die means defining the ultimate shape and contours of said disc; trim die means supported by said machine base interfitting with said shape-forming die means to define the inside and outside diameter of said disc; a series of perforation trim elements received in recesses conforming to the shape of said perforation elements around the periphery of said ringlike die element; a plurality of perforation trim element support pins extending from the bottom surface of said pErforation trim elements through openings in said shape-forming die element to be supported by said machine base; said shape-forming die and trim die means and perforation trim elements having blank sheet receiving surfaces positioned at generally the same level for initial pressurization of the opposite side of said flexible die element, whereby said contours of said disc are formed by pressurization of said flexible die element and said disc is trimmed and perforated by displacement of said rigid shape-forming die toward said flexible die element.

2. Apparatus as in claim 1 wherein: said trim die means comprise: a base disc positioned over said actuating means; an annular peripheral support ring positioned on said machine base and supporting the periphery of said base disc above said machine base; an outer retainer ring element extending around the periphery of said base disc and secured to said machine base, said outer retainer ring having an upper support surface above the base disc; a circular trim die element integral with said base disc and defining the inner diameter of said ringlike disc; an annular trim die element supported by said outer retainer ring element at the same level as said circular trim die element and defining the outer diameter of said ringlike disc; said shape-forming die means comprises: an annular shape-forming die element positioned above said base disc and between said trim die elements; means for connecting said shape-forming elements to said actuating means whereby said shape-forming die element is displaced relative to said trim elements.

3. Apparatus as in claim 1 wherein said actuating means includes a plurality of axially displaceable actuating rods extending from said machine base and in a generally circular pattern, and wherein said shape-forming die connecting means comprises: a displaceable disc positioned beneath said base disc and within said peripheral support ring, said displaceable disc being supported on its bottom side by said actuating rods; a plurality of displaceable rods positioned around the periphery of said central disc and extending through holes in said base die to abut the bottom surface of said shape-forming die element.

4. Apparatus as in claim 1 further comprising a plurality of support rods extending through openings in said displaceable disc and abutting the bottom side of said base disc element radially inward of said peripheral support ring.

5. Apparatus as in claim 4 wherein said perforation trim elements are positioned at regularly spaced intervals around the circumference of said shape-forming ringlike die element and said perforation trim element support pins are supported by said base disc and said displaceable rods which abut said shape-forming die element extend through holes formed in said base disc between each of the adjacent perforation-forming elements around the periphery of said shape-forming die element.