AU709913B2 - Improved lightweight ram for bodymaker - Google Patents

Description

2 IMPROVED LIGHTWEIGHT RAM FOR BODYMAKER Background of the Invention The invention relates to the construction of a ram that is utilised in high speed apparatus for forming elongated one piece metal can bodies from relatively shallow cups, and more specifically relates to an improved lightweight ram with increases integrity against stresses produced during the operation of the bodymaker.

The main section or body of a so-called two piece metal container or can of the type very often used for beer/beverages includes an elongated cylindrical sidewall, an integral bottom and an open top. Such bodies are often .formed in drawing and ironing machines of the type described in US Patent No. 3,704,619 issued 5 December 1972 to 15 E. Paramonoff for Redraw Blankholder Positioning Mechanism for Cup-Shaped Article Formers such as Metallic Can Body Formers and the Like, US Patent No. 3,735,629 issued 29 May 1973 to E. Paramonoff entitled Apparatus for Forming One Piece Metallic Can Bodies, and US Patent No. 4,530,228 issued 23 July 1985 to W. Snyder and D. Dettmer for Apparatus for Producing Seamless Container Bodies. The apparatus described in the aforesaid patents produce can bodies from blanks in the form of relatively shallow cups, by having a reciprocated ram drive each cup through a die pack which is a series of ringlike die elements having openings that are graduated. Each blank passes through the largest opening first, and each subsequent opening that the blank is driven through is slightly smaller than the preceding opening through which the blank has been driven.

A replaceable punch mounted to the ram at the front thereof engages each cup to drive it through the die pack.

The rear end of the ram is connected to the drive means that reciprocates the ram along its horizontally positioned longitudinal axis through a forward working stroke followed by a rearward return stroke.

Conventionally, rams are manufactured from a single Spec: P19997T 3 piece of barstock. This imposes severe limitations on readily machining the interior of the hollow elongated main centre section of the ram. This problem arises because the axial passages at both ends of the ram are limited in diameter, being considerably less than the centre section diameter that will still enable the centre section to provide the required mechanical strength (without having excessive wall thickness). Thus, in the prior art, wall thickness of the main centre section was unusually considerably greater than necessary to meet strength requirements so that the rams were unnecessarily heavy.

In US Patent No. 5,208,435 a ram is provided constructed as a weldment in which there is an elongated tube, a tail piece metallurgically bonded to one end of the tube and a nose piece metallurgically bonded to the other end of the tube. While effective, this ram could *see*: 0 experience excessive stress levels in the weld zone, Cc particularly where the tail piece is bonded to the tube, with the effects of these stresses being magnified when the 20 welds have imperfections.

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Summary of the Invention An object of the present invention is to address one

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or more of the above identified deficiencies of the prior .art. The present invention provides a lightweight ram for 25 high speed apparatus that produces relatively elongated can bodies by driving relatively shallow cups through a ring type die means, said ram including: an elongated thin-walled tube portion, a nose

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section and a tail section; 30 said nose section constructed to mount and COC c.

operatively position a punch on said ram; said tail section adapted for connection to a driving device that reciprocates the ram along its longitudinal axis; said sections and said tube portion being in axial alignment, with said tube portion being interposed .c c C C~ c C c C S c c Cc C ec cccC cC c 4 between said sections and said nose and tail sections projecting in opposite directions from opposite ends of said tube portion; a metallurgical bond fixedly securing said tail section to said tube portion at one end; said tube portion and said nose section being constructed from a single integral piece of material.

Preferably, the thin-walled tube section and said nose section are formed by drilling out said single integral piece of material.

It is preferred that the tail end of the tube portion and said tail section are constructed so that a portion of one will overlap a portion of the other when they are fixedly secured together.

Further, the portion of overlap may, for example, be at least inch wide.

It is preferred that the tail end of the tube portion and said one section are first assembled by heating the overlapping portion to expand it and then shrink fitting 20 the tail end and said one section together.

Preferably further a weld metallurgically bonds the tube portion to said tail section.

e *The single integral piece of material and said one *z.i 25 section may, for example, be constructed of alloy steel.

25 Preferably the tube portion has a length that is greater than one hundred times its wall thickness.

It is preferred that there are aligned axial passages through the nose section, the tube portion and the tail section, with the axial passage of the tube portion having ooooo 30 a diameter of at least two times the diameter of the axial 999*99 passages for both the nose section and the tail section.

Further, the tube portion may, for example, have an axial passage that is of a diameter which is greater than of the outer diameter of the tube portion.

The invention extends to a method for constructing a lightweight steel ram for high speed apparatus that :2 RA 99 a 41 9* 9 99 9 9 99 produces relatively elongated can bodies by driving relatively shallow cups through a ring type die means, said method including the steps of: constructing a nose section adapted to mount and operatively position a punch of the ram, constructing an elongated thin-walled tube portion and constructing a tail section adapted for connection to a drive means for reciprocating the ram along its longitudinal axis, with said tube portion and said nose section being constructed from a single integral piece of material and said nose section being at one end of said tube portion; metallurgically bonding said tail section to the other end of the tube portion to form a ram in which the nose section, the tube portion and the tail section are axially aligned.

Preferably the metallurgical bonding is the result of welding.

Preferably further following the metallurgical bonding steps, the ram is subjected to stress relieving and 9 *O 20 carburising.

It is preferred that the method also includes the steps of: S'heat treating said tail section and the tube portion prior to bonding them together; and L" 25 stress relieving the assembled tail section and tube portion only at localised areas adjacent the interface .It..

3 -between said tube portion and said tail section.

Preferably the tube portion and the nose section are '"constructed by drilling out material from said single piece 30 of material.

oooo• Preferably wherein the tail end of the tube portion and said tail section are constructed so that there is partial overlap between them when they are secured together.

More preferably the partial overlap is at least k inch wide.

"9 9 99 9 99 9. 99 999 6 It is preferred that the tail end of the tube portion and said tail section are first assembled by heating the partial overlap to expand it and then shrink fitting the tail end and said tail section together.

To produce a relatively lightweight ram, a unitary structure can be constructed by metallurgically bonding a nose piece to a body, the body constructed from a single integral piece having an elongated thin-walled tube section with a front end and a tail piece section adapted for connection to a drive means that reciprocates the ram along its longitudinal axis. In a preferred embodiment of the present invention, the unitary structure is constructed by metallurgically bonding the tail section to a rear end of the body, the body being constructed from a single integral piece having an elongated thin-walled tube section and a nose piece constructed to mount and operatively position a punch on the ram. Preferably the front end of the body and the nose piece, or the rear end of the body and the tail *5e section, have overlapping portions and are assembled by 20 shrink fitting together. Bonding is carried out by welding which achieves attachment strength that is for all practical purposes equal to the strength found in a ram manufactured from a single piece of barstock. Preferably, tube wall thickness is selected so that it does not exceed 25 substantially that thickness required to provide sufficient .o strength for the job that the ram is required to perform thereby minimising weight. The reduction in weight achieved by welding two pieces together to form the ram is significant and results in increased can production because 30 an increase in the cyclic rate of the machine is permitted.

Accordingly, a primary aspect of a preferred embodiment of the instant invention is to provide a relatively lightweight ram for a can body maker.

Another aspect of a preferred embodiment is to provide a ram of this type that is constructed of two elements metallurgically bonded together to form a unitary 7 structure.

Another aspect of a preferred embodiment is to provide a ram of this type in which the two elements are also shrink fit together.

Another aspect of a preferred embodiment is to reduce the level of bending stress at the weld joint, supported by the overlap shrink fit area.

Still another aspect of a preferred embodiment is to provide a ram of this type that is manufactured by welding techniques.

A further aspect of a preferred embodiment is to provide a ram of this type in which the main elongated centre section thereof has a length to wall thickness ratio greater than one hundred.

A still further aspect of a preferred embodiment is to provide a ram of this type which permits increased machine speed.

These aspects as well as other features of this 9..

,invention shall become readily apparent after reading the following description of the accompanying drawings in which: Brief Description of the Drawings Figure 1 is a partially sectioned side elevation of a 9.4.

lightweight ram constructed in accordance with the 25 teachings of the instant invention; Figure 2 is a partially sectioned side elevation of the body of the lightweight ram of Figure 1; Figure 3 is an end view of the body of the lightweight ram looking in the direction of arrows 3-3 of Figure 2; *9e a 30 Figure 4 is a partially sectioned side elevation of the nose piece of the lightweight ram of Figures 1-3; Figure 5 is an end view of the nose piece of the lightweight ram looking in the direction of arrows 5-5 of Figure 4.

Now referring to the Figures.

8 Detailed Description of the Invention Figures 1 to 5 illustrate a lightweight ram for high speed apparatus that produces relatively elongated can bodies by driving relatively shallow cups through a ring type die means.

Ram 10 is constructed by utilising weld 14 to metallurgically bond nose piece 12 to the front end 19 of thin-walled tubular centre section 11 of body 15. Body is constructed of a single integral piece (ie. single piece construction) having an elongated thin-walled tube section 11 with a front end 19 and a tail piece section 13. The body is preferably constructed by drilling out material from a solid bar or tube to form the thin-walled tube section 11 and integral tail piece section 13.

15 Advantageously by construction of body 15 having an integral tube section 11 and tail piece section 13, a weld or joint between these two sections is eliminated at a point on the ram 10 where increased stresses are exhibited during the bodymaker operation, thus increasing the 00 20 structural integrity of the ram as there is no joint to break.

Typically, main section 11 has a length L that is approximately 42 inches or less and is at least one hundred

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times greater than the wall thickness T of tube section 11.

In a practical construction, tube section 11 has an outer diameter of approximately 2.5 inches and an inner diameter of approximately 2 inches. This results in a wall thickness of inch which is a reduction of as much as 64% 00*00.

of the 5/8 inch to 11/16 inch wall thickness of the central section in prior art rams that are machined from a single piece of bar stock. When the wall thickness of the tube section 11 is 1/8 inch, this is an 82% reduction from the 11/16 inch wall thickness found in the prior art.

Preferably the tube section 11 has an axial passage that is of a diameter which is greater than 75% of the outer diameter of the tube section 11.

9 Suitable axial lengths for nose piece 12 and tail piece section 13 of the body are approximately 6.6 inches and 1.7 inches, respectively. The diameters of the axial passages 16,17 for the respective nose and tail pieces are approximately 3- of an inch. The diameter of the axial passage of the tube section 11 is preferably at least two times the diameter of the axial passages for both the nose piece 12 and the tail piece section 13.

Nose piece 12 is adapted to mount and operatively position a punch nose and sleeve (not shown) with the latter surrounding and being closely fitted to cylindrical outer surface portion 18 of nose piece 12. Punch elements can be secured in place by retainer screw having external threads that mate with internal threads at the front of 15 passage 16. A punch nose can be secured to the nose piece 0000 12 depicted in Figure 1 by a punch nose retainer screw.

Tail piece section 13 is adapted to be connected to a 2 drive means (not shown) for reciprocating ram 10 along its longitudinal axis 25. Suitable drive means for am 10 as 20 well as other details of can body forming apparatus are described in the aforesaid US Patent Nos. 3,704,619, 3,735,629 and/or 4,530,228. The teachings of these three patents are incorporated herein by reference.

Welding that forms weld 14 and metallurgical bonds elements 12 and 15 achieves attachment strength that is, for practical purposes, equal to having a unit of single 0 woo piece construction. Preferably, in order to reduce the level of stress at weld 14, the front end 19 of the tube "000. .section 11 and the nose piece 12 are constructed so that a portion of one will overlap and closely fit over a portion of the other in order that they may be shrink fit together, i.e. they are assembled by heating the overlapping portion of front end 19 to expand it and snugly fit it onto the underlying portion 20. The overlapping portions are at least inches preferably 1- to 1 inches to achieve a good shrink fit. Suitable shrink fitting is carried out by 10 heating the body 15 to 400-450°F followed by inserting the underlying portion 20 of the nose piece 12 into the overlapping portion of the front end 19 of the body Shrink fitting the nose piece 12 and body 15 together helps keep the stresses away from the weld during the bodymaker operation, i.e. by distributing all annular stress levels caused by bending to the weld joint area, thus increasing the integrity of the ram 10. The weld 14 can be formed by a conventional gas-shielded tig-arc weld. Test specimens were pull tested at 100,000 lbs. tension without failure at the weld joint.

Because the wall of tubular main section 11 is essentially no thicker than required, ram 10 is relatively lightweight so that inertia forces are reduced. Comparing 0 15 ram 10 with conventionally drilled rams of one piece e9 construction, reductions in weight of up to about 45% are obtainable. Because of this foundation, vibration is 2 lessened and machine wear slows down considerably, thereby permitting machine speed to be increased without harmful 20 effects. Ram 10 is also interchangeable with rams of conventional one piece construction.

Elements 12 and 15 are constructed of alloy steel, ,.with 9310 VAR being suitable for this purpose. After elements 12 and 15 are axially aligned, shrink fit and then bonded together by weld 14, the assembly is subjected to stress relieving, carburising and finish machining operations. As an alternative, elements 12 and 15 before they are assembled, and after applying weld 14, are stress relieved only at localised areas adjacent the weld 14.

In a preferred embodiment of the present invention (not shown in the drawings), the ram is constructed conversely by utilising weld to metallurgically bond the tail piece section to the rear end of the body. The body is constructed of a single integral piece having an elongated thin-walled tube section and a nose piece.

11 Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.

In the claims which follow and in the preceding summary of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprising" is used in the sense of "including", i.e. the features specified may be associated with further features in various embodiments of the invention.

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5 12 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A lightweight ram for high speed apparatus that produces relatively elongated can bodies by driving relatively shallow cups through a ring type die means, said ram including: an elongated thin-walled tube portion, a nose section and a tail section; said nose section constructed to mount and operatively position a punch on said ram; said tail section adapted for connection to a driving device that reciprocates the ram along its longitudinal axis; said sections and said tube portion being in axial alignment, with said tube portion being interposed between said sections and said nose and tail sections projecting in opposite directions from opposite ends of said tube portion; St 4* a metallurgical bond fixedly securing said tail section to said tube portion at one end; said tube portion and said nose section being constructed from a single integral piece of material.

2. A ram as claimed in claim 1 wherein said tube portion and said nose section are formed by drilling out said single integral piece of material.

25 3. A ram as claimed in claim 1 or claim 2 wherein 0e• the tail end of said tube portion and said tail section are constructed so that a portion of one will overlap a portion the other when they are fixedly secured together.

4. A ram as claimed in claim 3 wherein the portion of overlap is at least 4 inch wide.

A ram as claimed in claim 4 wherein the tail end of the tube portion and said tail section are first assembled by heating the overlapping portion to expand it and then shrink fitting the tail end and said tail section together.

Claims (12)

1. 6. A ram as claimed in any one of claims 1 to 5 in which a weld metallurgically bonds said tube portion to said tail section.
2. 7. A ram as claimed in any one of claims 1 to 6 in which the single integral piece of material and said tail section are constructed of alloy steel.
3. 8. A ram as claimed in any one of claims 1 to 7 in which said tube portion has a length that is greater than one hundred times its wall thickness.
4. 9. A ram as claimed in claim 8 wherein there are aligned axial passages through said nose section, said tube portion and said tail section, with the axial passage of said tube portion having a diameter of at least two times the diameter of the axial passages for both said nose 15 section and said tail section.
5. 10. A ram as claimed in claim 8 wherein said tube portion has an axial passage that is of a diameter which is greater than 75% of the outer diameter of said tube portion. 20 11. A method for constructing a lightweight steel ram for high speed apparatus that produces relatively elongated can bodies by driving relatively shallow cups through a ring-type die means, said method including the steps of: constructing a nose section adapted to mount and operatively position a punch of the ram, constructing an elongated thin walled tube portion and constructing a tail section adapted for connection to a drive means for reciprocating the ram along its longitudinal axis, with said tube portion and said nose section being constructed from a single integral piece of material and said nose section being at one end of said tube portion; metallurgically bonding said tail section to the other end of the tube portion to form a ram in which the nose section, the tube portion and the tail section are axially aligned. 14
6. 12. A method for constructing a ram as claimed in claim 11 in which the metallurgical bonding is the result of welding.
7. 13. A method for constructing a ram as claimed in claim 11 or claim 12 in which, following the metallurgical bonding steps, the ram is subjected to stress relieving and carburising.
8. 14. A method for constructing a ram as claimed in any one of claims 11 to 13 also including the steps of: heat treating said tail section and the tube portion prior to bonding them together; and stress relieving the assembled tail section and ease tube portion only at localised areas adjacent the interface 9 between said tube portion and said tail section.
9. 15. A method for constructing a ram as claimed in any one of claims 11 to 14 wherein said tube portion and said o. -nose section are constructed by drilling out material from said single piece of material.
10. 16. A method for constructing a ram as claimed in 20 claim 15 wherein the tail end of said tube portion and said C. tail section are constructed so that there is partial overlap between them when they are secured together. .17. A method for constructing a ram as claimed in claim 16 wherein the partial overlap is at least 1 inch wide.
11. 18. A method for constructing a ram as claimed in claim 17 wherein the tail end of said tube portion and said tail section are first assembled by heating the partial overlap to expand it and then shrink fitting the tail end and said tail section together.
12. 19. A lightweight ram for high speed apparatus substantially as herein described with reference to any one or more of the exemplary embodiments. 15 A method for constructing a lightweight steel ram for high speed apparatus substantially as herein described with reference to any one or more the exemplary embodiments. Dated this 30th day of June 1999 SEQUA CORPORATION By their Patent Attorneys GRIFFITH HACK 0e 0 0** S. D g ABSTRACT A lightweight ram (10) for high speed apparatus that produces relatively elongated can bodies by driving relatively shallow cups through a ring type die means, said ram including: an elongated thin-walled tube portion a nose section (12) and a tail section (13); said nose section (12) constructed to mount and operatively position a punch on said ram; said tail section (13) adapted for connection to a driving device that reciprocates the ram along its longitudinal axis; said sections (12,13) and said portion (15) being in 0O axial alignment, with said portion (15) being interposed So. 15 between said sections (12,13) and said sections (12,13) projecting in opposite directions from opposite ends of said portion S.. a metallurgical bond fixedly securing one of said sections (12,13) to said portion 20 said portion (15) and another of said sections being constructed from a single integral piece of material. 0S go 00 0 Spec: P19997T