Apparatus and method for forming a tubular frame member

• US 5,353,618 A
• Filed: 08/23/1993
• Issued: 10/11/1994
• Est. Priority Date: 08/24/1989
• Status: Expired due to Term

• Current Assignee: Aquaform Incorporated
• Original Assignee: Armco Steel Corporation (AK Steel Holding Corporation), Price Enterprises, Ltd.
• Inventors: Roper, Ralph E., Webb, Gary A., Tyger, Douglas W.
• Primary Examiner(s): JONES, DAVID B
• Application Number:
  US08/077,616
• Time in Patent Office: 414 Days
• Field of Search: 72/56, 72/57, 72/58, 72/59, 72/61, 72/62, 72/367, 72/369, 29/421.1
• US Class Current: 72/58
• CPC Class Codes: B21D 26/045 Closing or sealing means
• CPC Class Codes: B21D 26/047 Mould construction B21D26/037 - B21D26/045 take precedence
• CPC Class Codes: B21D 9/15 using filling material of indefinite shape, e.g. sand, plastic material filling of tubes with such material B21D9/16
• CPC Class Codes: B60G 2206/8107 by hydroforming
• CPC Class Codes: Y10T 29/49805 Shaping by direct application of fluent pressure

Abstract

An apparatus for forming a frame member for an automobile from a tube blank applies internal hydraulic pressure to the blank, tangent bends and preforms the internally pressurized blank into a preformed tube having a desired horizontal profile configuration, then forms the preformed tube into a finally formed frame member having a desired vertical profile configuration and a desired, varying cross-sectional configuration by placing the preformed tube in a stuffing ledge apparatus having a lower die with an upwardly facing ledge and vertically extending, punch engaging surfaces and a punch having a downwardly facing ledge and vertically extending, die engaging surfaces, internally pressurizing the tube, and then ramming the punch downwardly to form the tube into the finally formed frame member, the ledges and vertically extending surfaces substantially completely enclosing a portion of the tube before and while the punch and die come together to form the tube into the finally formed frame member. The forming components in each apparatus are submerged in an aqueous bath, allowing the blank and tube to automatically fill themselves, thereby facilitating sealing and pressurizing of the tube.

Claims

1. An apparatus for forming a complex-shaped frame member from a cylindrical tube blank having first and second opposite ends, comprising:

a base;

a die mounted upon said base and defining a pair of vertical parallel punch engaging surfaces and a horizontal upwardly facing lower stuffing ledge therebetween;

a punch defining a pair of vertical parallel die engaging surfaces and a horizontal downwardly facing upper stuffing ledge therebetween, and wherein said punch is suspended above said die such that said die and punch engaging surfaces are constantly parallel and such that said upper and lower stuffing ledges are in constant vertical alignment along a path parallel to said punch and die engaging surfaces;

wherein said punch has a retracted, non-engaging position above and away from said die;

wherein said die is adapted to receive a tube blank upon its lower stuffing ledge when said punch is in the retracted position;

wherein said punch has a fully extended position wherein said die engaging surfaces are in substantially complete mutually cooperating engagement with said punch engaging surfaces so as to surround a tube blank and wherein said upper and lower stuffing ledges together define the desired complex-shaped frame member configuration;

wherein the apparatus further includes punch moving means for reciprocating said punch between said retracted position and said fully extended position.

2. The apparatus for forming a complex-shaped frame member of claim 1 wherein said punch further includes a tube trapping position between said retracted position and said fully extended position wherein said die engaging surfaces are in partial engagement with said punch engaging surfaces and wherein said upper stuffing ledge, said lower stuffing ledge, one of said punch engaging surfaces and one of said die engaging surfaces together trap a portion of a tube blank between its first and second ends when the tube blank is resting upon said lower stuffing ledge.

3. The apparatus for forming a complex-shaped frame member of claim 2 further including sealing means mounted to said base and for sealing the ends of a tube blank which is resting upon said lower stuffing ledge and for applying a desired internal hydraulic pressure to the blank.

4. The apparatus for forming a complex-shaped frame member of claim 3 wherein said sealing means is adapted to pressurize the blank to a value just below that which will exceed the yield limit of the blank and cause the blank to expand.

5. The apparatus for forming a complex-shaped frame member of claim 1 further including boost pressure means for applying an internal hydraulic boost pressure to the blank when said punch is in said fully extended position, said boost pressure being sufficient to radially expand the walls of the blank into the desired complex-shaped frame member configuration defined by said mutually cooperating ledges.

6. A method for producing a frame member from an elongated cylindrical tube blank having first and second ends, comprising the steps of:

providing forming means for forming a tube blank, said forming means including;

a die defining a first vertical, punch engaging wall and a first vertical, punch engaging heel and an horizontal upwardly facing, lower stuffing ledge therebetween, a punch defining a second vertical, die engaging wall and a second vertical, die engaging heel and a horizontal downwardly facing, upper stuffing ledge therebetween, and wherein said upper and lower stuffing ledges are in constant vertical alignment;

placing a tube blank upon said lower stuffing ledge;

ramming said punch downward to a tube trapping position whereby said second vertical wall slidingly engages with said first vertical heel, said second vertical heel engages with said first vertical wall, and said first and second vertical walls and said upper and lower stuffing ledges trap a portion of the tube blank between the first and second ends; and

,

further ramming said punch downward to a fully extended position whereby said first and second stuffing ledges completely enclose said portion of the tube.

7. An apparatus for forming a complex-shaped frame member from a cylindrical tube blank having first and second opposite ends, comprising:

a base;

a die mounted upon said base and defining a vertical, punch engaging wall which smoothly transitions at its bottom into an horizontal upwardly facing lower stuffing ledge, the ledge transitioning at an acute angle into a first vertical heel and wherein said die is adapted to receive a tube blank upon its lower ledge;

a punch defining a vertical, die engaging wall which smoothly transitions at its top into a horizontal downwardly facing upper stuffing ledge, the upper ledge transitioning at an acute angle into a second vertical heel, said upper and lower stuffing ledges being in constant vertical alignment;

sealing means mounted to said base and for sealing the ends of a tube blank which is resting upon said lower stuffing ledge and for applying a desired internal pressure to the blank during forming of the blank by said punch and die;

wherein said punch is operable to be rammed down into a tube trapping position, wherein when a blank is disposed upon the lower ledge, the second heel slides downwardly along the punch engaging wall, the die engaging wall slides downwardly along the blank and along the first heel until the upper and lower ledges and the die engaging walls together define an enclosed cavity trapping a portion of the blank therewithin, and wherein said punch is further operable to be rammed down from the tube trapping position to a fully extended position wherein the upper and lower stuffing ledges have acted upon the blank to form a complex-shaped frame member having a desired horizontal, vertical and cross-sectional profile.

8. The apparatus for forming a complex-shaped frame member of claim 7 further including walls which, with said base, form a tub, wherein said tub contains a liquid, and wherein the sealing means and the blank are both submerged when the blank is disposed upon the lower ledge.

9. The apparatus for forming a complex-shaped frame member of claim 8 wherein said sealing means includes a first tool defining an axial bore and having an open end and an o-ring mounted inwardly from the open end, said tool further defining a port inwardly from the open end including pressure relief means connected at said port for relieving hydraulic pressure within the blank which exceeds a predetermined value.

10. The apparatus for forming a complex-shaped frame member of claim 9 wherein said sealing means further includes a second tool identical to said first tool, and wherein said first and second tools are operable to be moved between a retracted position away from a blank which rests upon said lower ledge and an extended, engaged position whereby the first and second ends of a blank resting upon said lower ledge are telescopically received within the bores of respective said first and second tools, whereby the o-rings form circumferential seals between the ends and the corresponding tools, and wherein movement of said tools from said retracted position to said extended position pressurizes the interior of the blank.

11. The apparatus for forming a complex-shaped frame member of claim 10 wherein in said fully extended position, said upper and lower stuffing ledges define a tube forming cavity having cross-sectional perimeters which are greater than corresponding cross-sectional perimeters of the tube blank and wherein the apparatus further includes boost pressure means for applying a desired boost hydraulic pressure through the port of at least one of said first and second tools to the interior of the tube, said boost pressure means being operable to deactivate said pressure relief means, and wherein said desired boosted hydraulic pressure is sufficient to substantially completely expand the blank within said tube forming cavity.