US2748634A - Apparatus for contour rolling - Google Patents

Description

June 5, 1956 R. P. KOEHRING ET Ax. 2,748,534

APPARATUS FOR CONTOUR ROLLING A Filed April 10, 1952 3 Sheets-sheet 1 INI/ENTORS` [ar] E IA/JY'EHS 3 WM June 5, 1956 R. P. KOEHRING ET AL 2,748,634

APPARATUS FOR CONTOUR ROLLING 5 Sheets-Sheet 2 Filed April lO, 1952 f INVENToRs f x 54 C7 4 1Y0/5nd E KBJ'Jhq [far] E. MXENS 32 WM W June 5, 1956 R. P. KOEHRING ET Ax. 2,748,534

APPARATUS RoR coNTouR ROLLING 5 Sheets-Sheet 5 Filed April lO, 1952 y INVENTORS Edf] E', MMT/75 fafa/7a ffice/711mg United States Patent O APPARATUS FOR CONTOUR ROLLING Roland P. Koehring and Carl E. Wilkens, Dayton, Ohio, assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application April 10, 1952, Serial No. 281,554

1 Claim. (Cl. 80-23) i This invention relates to an apparatus for contour rolling articles made from sintered metal powders.

It is, therefore, the basic object of the invention to provide an apparatus for shaping, while cold, articles from sintered metal powders which are molded and sintered to the approximate shape desired and are then contour rolled to the exact shape desired.

Another object of the invention is to provide an apparatus for contour rolling articles made from the sintered metal powders wherein the rolling operation accomplishes two major results, namely, the proper shaping of the article and an increase in the physical properties, such as, density, tensile strength, etc., of the article either over its entire extent or at predetermined and selected portions thereof.

In carrying out the above object, another object of the invention is to provide apparatus for contour rolling projectiles comprising three contouring rolls wherein one of said rolls utilized includes an end iiange predetermining the length of the projectile and wherein back-up ro-lls are provided for each contouring roll, which back-up rolls are suitably recessed for clearance purposes adjacent portions of the contour rolls which are not subjected to maximum stress.

A still further object of the inventio-n is to provide an apparatus for contour rolling articles and similar objects wherein three contour rolls are utilized together with three back-up rolls therefor and wherein one of the contour rolls is driven, which driving force is transmitted to the other rolls through suitable gearing so that all rolls are positively rotated at the same speed.

Another object of the invention is to provide an apparatus wherein gearing is provided for associating the various contour rolls and wherein the one roll is adjustably mounted for vertical displacement and isv hingedly connected to the driving gear so as to always be held in similar relation to said gear regardless of displacement of the roll.

it is still a further object of the invention to provide an apparatus for contour rolling articles made from sintered metal powders wherein a pair of rolls relatively movable with respect to each other are provided, which rolls have the desired contour of the part to be formed on the surfaces thereof, a third member being provided to position the part between the'` contour rolls during the rolling operation.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments o-f the present invention are clearly shown.

In the drawings:

Fig. 1 is an end view of a contour rolling apparatus.

Fig. 2 is a sectional view taken on line 2-2 of Fig. l.

Fig. 3 is a sectional view taken on line 3-3 of Fig. 2.

Fig. 4 is a diagrammatic end view showingv one contour roll in displaced position.

Fig. 5 is a diagrammatic end view of the apparatus shown in Fig. 4, wherein the displaced roll is in contouring position.

v 2,148,634 Patented June 5 1956 Fig. 6 is a side view of another embodiment of the apparatus used for contouring.

Fig. 7 is a view taken on line 7--7 of Fig. 6.

Fig. 8 is a diagrammatic view of the contouring rolls shown in Fig. 7, showing the relative position of the rolls, pushing member and part to be contoured.

ln the manufacture of cylindrical articles from sintered metal powder; for example, in the manufacture of projectiles and the like, it is quite ditiicult to briquet the metal powder prior to sintering in the exact shape designed, whereby, when the article is sintered, additional machining operations are normally required to bring the article to the exact shape and size desired.

Then too, in cylindrical articles of this type, it is very ditiicult to size thearticle after sintering by the usual methods used in powder metallurgy, for example, by pressing through a button die or the like.

Furthermore, it is often very desirable to markedly increase the density or other physical properties, such as, tensile strength, after the sintering operation. This can be accomplished by suitable pressing of the article which, due to its porosity, can be changed in over-all dimensions slightly to provide for an increase in density and also provide increase in tensile strength. Then too, in an article, such as a projectile, it is often very desirable to have one portion of higher density than another, for example, the driving band should be relatively soft whereas the body of the projectile is preferably rather hard and dense so as to prevent distortion due to tiring. Also, it is often desirable to have a relatively soft nose portion so that the projectile will shatter or mushroom, etc., as desired. Thus it is apparent that varying density throughout a projectile is an optimum condition which is quite impossible to obtain on cast objects and which, prior to our invention, was diicult if not impossible to obtain on cylindrical articles made from sintered metal powders.

We have found that contour rolling of sintered metal powders in the form of projectiles, etc., can vary well be carried out to not only size the article to the exact size desired and to shape the article at certain portions thereof and in addition, we have found that it is possible to selectively regulate or control the density of predetermined portions of the article during the sizing operation. In this instance, the sizing is carried out by contour rolling since the article is generally cylindrical in shape.

Contour rolling of such an article may be accomplished on apparatus as shown in the accompanying drawings. This apparatus 2G includes three contour rolls 22, 24 and 26 positioned at 120 apart. Each roll is journaled at both ends in end plates 28 and 3i) which are carried by a base plate 32 of the apparatus. The uppermost roll 22 is journaled on a slidable plunger member 34 which is movable vertically so that the roll 22 may be moved toward or away from rolls 24 and 26. On the uppermost end of the plunger 34 is a platform 36 whereby the roll 22 may be forced downwardly through a press member, not shown, acting against the platform 36. In other words, the entire apparatus 2i) may be positioned in a press with the base plate 32 against the lower platten and the platform 36 against the upper platten. The part to be contour rolled is a projectile 38, and as the press forces the. contour roll 22 downwardly, the article 38 is sized between the three rolls 22, 24 and 26. It will be noted that each of the rolls 22, 24 and 26 is backed up by backup rolls designated at 40, 42 and 44. These backup rolls are also journaled on side plates 28 and 30 and are in contact over the major portion of the surfaces of the contour rolls 22, 24 and 26 respectively. The backup rolls are merely idler rolls which turn with the contour rolls. The contour rolls, however, are driven by a suitable mechanism such as a motor through a gear reducer attached to the shaft 46. Shaft 46 is in direct connection with roll 24 which has a gear 4S thereon that meshes with a large idler gear 50. The idler gear 50 meshes with gear 52 attached to roll 22. Gear 43 also meshes with a second idler 54 which engages a gear 56 associated with the contour roll 26. Thus the contour roll 24 is directly driven by the prime mover and, through idlers 50 and 54, directly drives contour rolls 22 and 26, respectively.

Roll 24 is attached by a hinged member 58 to the idler gear t) which definitely controls the distance between the gears so that they are always in mesh. Similarly, gear 52 is carried by a hinged member 60 also attached to the Shaft of idler gear 50. ln this manner, as the roll 22 is raised vertically by the plunger 34, the gear 52 rides around the surface of gear 50 and remains in engagement therewith regardless of the vertical position thereof, Similarly, the gear 50 rides around gear 4S associated with roll 24, as noted in Fig. 4. The relation of immovable gear 48 to the idler 54 is constant whereby the gear 56 and its associated roll 26, which are also immovable, are constantly driven. Thus the hinge mechanisms 58 and 60 permit movement of the contour rolls 22 and 24 and their associated gears 48 and 52 while at no time permitting the gears to become unmeshed with the idlers 50 and 54 so that all of the rolls are positively driven in all positions of the apparatus.

The diagrammatic View in Figs. 4 and S wherein the hinged members 58 and 60 have been reduced in thickness, clearly show the adjustability of position of the gears while said gears remain in mesh.

Fig. 3, which is a cross sectional view through the apparatus, shows quite clearly how the article 38 is contour rolled between the three contour rolls together with the action of the backup rolls thereon. After the pressure is applied to the upper plate 36, the contour rolls, due to the compressibility of the porous metal article, move toward a common center on their 120 spaced axes and gradually roll into the article 38 the desired accurate contour while simultaneously increasing the density and tensile strength thereof.

The use of the backup rolls 40, 42 and 44 is quite necessary to the success of the invention. The contour rolls 22, 24 and 26 must necessarily be of rather small diameter which is more or less regulated by the diameter of the article to be rolled. In the instant case, the contour rolls have ridges at 62 which bite into the article, such as a projectile, and hold the article spaced in a horizontal position. The larger diameter end flanges 64 likewise aid in this positioning. The drive band on the article is noted at 66 and is not appreciably compressed due t0 the fact that the grooves 68 are provided in the contour rolls. Thus, the projectile is provided with an integral driving band that is relatively soft and of lower density than the remainder of the article. At the forward end of the contour rolls, the nose portion of the projectile is shaped and it will be noted that one roll, namely, roll 22, has a large diameter flange 70 thereon which slightly overlaps the ends of rolls 24 and 26. This definitely sets the length of the projectile and likewise prevents the projectile from sliding forward within the rolls and thereby getting out of position. The roll 22 is backed by roll 40 and by a large flange 72 on the roll 40. As the pressure is placed on the projectile, the main body portion of the projectile is formed by the major portion of the rolls which are backed up by backup rolls while the nose portion is formed between the three rolls and is definitely Set for length by the flange 70. Outward movement of the roll 22 is prevented by flange 72 on backup roll 40 rotating in groove 73. It will also be noted that all of the backup rolls have a groove 74 therein which registers with the flange 64 on the contour rolls and further prevents outward or radial movement of said rolls. Similarly, the backup rolls are relieved at 76 since the changing diameters would be difficult to back up and cause excessive friction as the rolls are moved.

The entire apparatus therefore -is one to provide pressure rolling on a compressible material wherein the contour rolls are positively driven for positively rotating the article to be contoured and wherein the contour rolls are positively backed up to pevent distortion or bowing thereof and are positively held against radial movement through flanges on the backup rolls. When the article has been properly contoured as determined by the extent of downward movement of the plunger member 34, member 34 is backed off the finished article 38, removed from the apparatus and another article is pressed therein for contouring.

A modification of the apparatus, as shown in Figs. l through 5, inclusive, is depicted in Figs. 6 through 8. 'Ihis modification eliminates the necessity of backup rolls as used in the apparatus shown in Fig. l, for example. When using three rolls, it is apparent that the diameter of the rolls limits the size of the article which may be rolled therebetween and therefore in order to roll a rather small diameter article, such as shown at 38 in Fig. 2, it is necessary to use small diameter rolls which do not have sufficient strength to prevent bowing. In order to strengthen such rolls, heavy backup rolls are necessary. In the embodiment of the apparatus, shown in Fig. 6, the necessity of backup rolls is eliminated through the use of two rotatable members which may be of any necessary size to yield the desired strength. The two rolls cooperate with a pushing member to center the part being contoured therebetween.

Referring specifically to Fig. 6, a frame member 71 is provided on which is journaled a stationary roll 73 and a movable roll which is carried on a frame member 77 slidable in tracks, not shown, in the member 7l. The member 77 is spring biased to cause rolls 75 to be spaced from rolls 73 except when pressure is supplied to the frame 77. For example, the entire apparatus may be placed in a punch press or other suitable mechanism to cause the frame 77 and its associated roll 75 to move toward the roll 73 in the frame 71.

In practice, stops are provided in the tracks so that the downward travel of the frame 77 may be adjustably limited. Each of the rolls 73 and 75 are driven by chains 80 and 82 which engage sprockets 84 and 86, respectively, carried by the shafts of the rolls 73 and 75. The other end of the chains 80 and 82 engage sprockets 88 and 90, not shown, which sprockets are driven by a suitable power mechanism, for example, a speed reducer driven by a motor, not shown. Thus the chains 80 and 82, through their associated sprockets and motor, cause the rolls 73 and 75 to rotate at a desired speed in the direction shown in Fig. 8 by the arrows on the rolls. The surfaces of the rolls 73 and 75 are contoured at 92 and 94 as noted in Fig. 7, so that an article, such as a projeetile, may be rolled therebetween to the desired size and contour, as previously discussed in connection with the apparatus shown in Fig. 1.

In order to hold the projectile or other object between the rolls 73 and 75, a. pusher 96, which is adjustable to or away from the common center of the rolls is provided. The pusher 96 has a hardened contact member 98 thereon which engages the part to be contoured. In this instance, it is preferable to have the part to be contoured so positioned between the rolls that the center of the part is approximately .001 to .003 displaced from the common center of the rolls toward the pusher 96. Thus, the pusher 96 maintains the part to be rolled between the rolls where it rotates as the rolls rotate. During the contouring operation, the frame 77 is pressed downwardly against its resilient mounting until the full and final contour is obtained on the part.

The pusher 96 is adjustably mounted on the frame 71 and may be moved inwardly or outwardly by means of a screw handle 100. Once this adjustment is properly made, it is usually unnecessary to further adjust the pusher since the travel of the frame 77 may be adjusted to cause the part 38 to assume the desired diameter during contouring.

If desired, it is also possible to cause the pusher to be operated through a rack and pinion, not shown, so as to move inwardly at the same rate of travel as the rolls 73 and 75 move toward one another. In this instance, the part 38 is maintained in substantially identical relation to the three parts of the contouring machine, namely, rolls 73 and 75 and pusher 96. In all cases, the pusher is mounted on the frame 71 with its contact member 98 engaging the part to be rolled as noted.

The contact member 98 is relatively small compared to the part 38 being contoured and presents very little friction so that no substantial galling action is apparent. The rubbing surface of member 98 may be slightly rounded to present a line Contact for reducing a friction. ln some cases, it may be desirable to replace the member 98, as shown, with a roller member to further reduce friction, although we have found that a hardened bar yields very satisfactory results. In either case the contact member 98 may be contoured if it contacts contoured portions of the part, although it is preferred to use a member 98 which includes a straight edge only for bearing against uncontoured portions only of the article 38. This may be accomplished since the extent of the member 98 is not critical, merely being used to maintain the part in position.

It will be noted that in both embodiments of the invention a pair of contour rolls are utilized which compress and contour the part to be shaped, while the part is being rotated therebetween. ln each instance, a third member holds the part in proper relative position with respect to the contouring rolls and in this manner, it will be apparent that both forms of the invention utilize similar functions to perform the contouring operation.

While the embodiments of the present invention as herein disclosed, constitute preferred forms, it is to be understood that other forms might be adopted.

What is claimed is as follows:

Apparatus for contour rolling cold porous metal articles of the approximate size and shape to the exact size and shape desired, comprising in combination; three rotatable contour rolls, two of said rolls being permanently mounted against any displacement and a third roll mounted for vertical displacement with respect to the other two rolls, gearing associating all three rolls for concomitant rotation, said gearing including a pair of gears movable during vertical displacement of said third roll for keeping all three rolls in geared relation at all times, three backup rolls, one being provided for each of said contour rolls and disposed on a line drawn through the axis of each of said contour rolls and the axis of the part to be contoured, a flange at one end of the displaceable roll adapted to continuously engage an abutting flange on the backup roll therefor for preventing lateral displacement of said displaceable roll, a second ange on the opposite end of said displaceable contour roll continuously engaging the groove in the backup roll therefor for aiding in preventing lateral displacement thereof and flanges in each of said permanently mounted contour rolls continuously riding in grooves in their respective backup rolls whereby the contour rolls are held against lateral displacement and in proper vertical alignment at all times.

References Cited in the le of this patent UNITED STATES PATENTS 672,516 Schinneller Apr. 23, 1901 1,015,412 Werckmeister Ian. 23, 1912 1,370,998 Roemer Mar. 8, 1921 1,493,836 Wurster May 13, 1924 2,139,872 Worthington Dec. 13, 1938 2,318,505 Long May 4, 1943 FOREIGN PATENTS 302,513 Germany Iuly 22, 1919

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