US2092188A - Process and apparatus for drawing metal strips - Google Patents

Description

A. SIMONS Sept. 7, 1937.

PROCESS AND APPARATUS FOR DRAWING METAL STRIPS Filed July 5, 1955 3 Sheets-Sheet l INVENTOR Aaron Samoa/s BY W ATTORNEYS A. SIMONS Sept. 7, 1937.

Filed July 5, 1955 PROCESS AND APPARATUS FOR DRAWING METAL STRIPS INVENTOR.

Aaron Simon/J .JTTURXFYS.

BY W PROCESS AND APPARATUS FOR DRAWING METAL STRIPS Filed July 5, 19-35 3 Sheets-Sheet 3 g -41 -42 I: E 5. -42

a. n 46 47 W 7% +11 49 y- NVENTOR- Aaro 4533920176 I y w ATTORNEYS.

Patented Sept. 7, .1937

UNITED STATES PATENT OFFICE PROCESS AND APPARATUS FOR DRAWING METAL STRIPS 14 Claims.

This invention involves a process and apparatus for the drawing of metal strips to reduce the thickness thereof. By the term strips I mean to include metal members regardless of the crosssectional form, and which may be flat, round or other shape. If flat they may be of any desired width, and include such widths as are ordinarily designated as plates or sheets. Heretofore the reduction in the thickness of flat metal strips has been effected by passing the strip between rollers so rotated that the surfaces engaging the strip move in the same direction as the strip, whereby the strip is advanced by the rollers which at the same time press it and reduce its thickness.

In reducing the diameter of round strips, such as wire, it has been common practice to draw or pull the wire through an apertured die, and this has proved satisfactory due to the low ratio of the surface of the cross-sectional area, but can be employed to effect only a small reduction in diameter as otherwise the pull required will stretch and further reduce the diameter of the 1 wire or break it beyond the die.

So far as I am aware no one has heretofore been able to draw fiat metal strips satisfactorily, particularly if the strip be comparatively wide in respect to the thickness because of the high ratio of surface to the cross-sectional area and the resulting extremely high tension required to draw the strip between opposing die surfaces adjusted to give substantial reduction in thickness, and no one has been able to draw round metal strips, such as wire, to effect a large reduction in diameter by a single passage through a single die. Cold drawing and rolling operations produce quite different types of structural changes in the surface portions of the metal operated on, and heretofore cold rolling of strips has imparted to the surface portions undesirable structural changes not present in drawn wire.

By means of my invention strips may be drawn to effect very substantial reduction in thickness and without exerting a pull or tension even as high as is necessary in wire drawing and in spite of the fact that the reduction in thickness is over a comparatively wide area in respect to the the direction of the strip, or may move in straight or curved lines at an angle to the direction of movement of the strip. Such angles may vary between 0 and 180 to the direction of movement of the strip. It is preferable that the drawing 5 surfaces move in directions having components at right angles to the direction of movement of the strip, and therefore exert equal and opposite tendencies toward lateral movement of the strip so that these tendencies balance each other 10 and the strip may move in a straight line in the direction of its length. By reason of the continuous movement of the engaging surfaces of the die members in opposite directions the resistance to the endwise movement of the strip 15.

between the die members is very greatly reduced and a comparatively small tension is required for pulling the strip lengthwise between the die members even though it undergo a substantial reduction in thickness by reason of the extent of 2 the spacing of the die members.

My improved process may be carried out in various types of apparatus. In the accompanying drawings certain of such types of apparatus are illustrated. In these drawings:

Fig. 1 is a plan view showing diagrammatically an apparatus including two members rotatable in opposite directions about the same axis,

Fig. 2 is a central longitudinal section through the form shown in Fig. 1, 30

Fig. 3 is a view similar to Fig. 1, but with members offset to eccentric positions.

Fig. 4 is a central longitudinal section through the form shown in Fig. 3,

Fig. 5 is a plan view showing diagrammatically 35 an apparatus including two members of the endless type having straight runs movable transversely of the strip,

Fig, 6 is a central longitudinal section through the form shown in Fig. 5, 40

Fig. '7 is a .plan view showing diagrammatically an apparatus including two members movable back and forth in straight lines,

Fig. 8 is a plan view showing diagrammati- 45 cally an apparatus including two members rotatable in the same directions about parallel axes and for drawing flat strips,

Fig. 9 is a central longitudinal section through the form shown in Fig. 8,

Fig. 10 is a v--w similar to Fig. 8, but for drawing round or other shaped strips,

Fig. 11 is a central longitudinal section through the form shown in Fig. 10,

Fig. 12 is a view on a larger scale showing portions of the two die members shown in Figs. 1 and 2,

Fig. 13 is a view similar to Fig. 6, but showing die members more in detail,

Fig. 14 is a vertical transverse section of the construction shown in Fig, 13,

Fig. is a view similar to Fig. 13, but of a different type of construction,

Fig. 16 is a transverse section through the construction shown in Fig. 15, and

Fig. 17 is an enlarged detail of a portion of Fig. 16.

My invention in its broad principles and in a simple form may be understood from the rather diagrammatic showing in Figs. 1, 2 and 12. In this construction there are employed a pair of rotary members In and II of disc type mounted coaxial and carried by shafts l2 and I3. These may be mounted in roller bearings 14 diagrammatically illustrated, and the two discs may be held against separation by thrust bearings l5 diagrammatically illustrated. The opposing faces of the two discs or rotary members l0 and l I have opposed annular die elements illustrated in Fig. 1 as ridges l6 and I1. These are illustrated in Fig. 12 as being formed on annular inserts l8 and IQ of tungsten carbide, hardened steel or other material of sufficient hardness to render it suitable for use in a drawing die presenting narrow fiat opposed surfaces.

The two members are rotated in opposite directions at the same speed, and the strip A to be drawn is fed between the two discs diametrically thereof so that they pass between the two die surfaces l6 and l! which are moving in opposite directions and substantially at right angles to the path of movement of the strip. The

axes of the two members Hi and II may be very.

slightly tilted in respect to each other so that the die surfaces l6 and II are slightly closer together at one side than they are at the other, and thus the strip is subjected to two successive drawing actions, first where it passed between the die surfaces at one side of the axis of rotation of the members and again'where it passed between the surfaces at the diametrically opposite side.

If the members In and II were held stationary the resistance to the endwise movement of the strip would be so great that the strip could not be pulled through without breaking if there were any substantial reduction in the thickness of the strip in passing between the die surfaces. I have discovered that by moving the die surfaces in opposite directions transversely of the strip, the resistance to the endwise movement of the strip between the die surfaces is very substantially reduced, and in fact reduced to such an extent that comparatively small tension is required to pull the strip through even though there is a substantial reduction in thickness effected in passing between the die surfaces. The die surfaces may vary according to the character of the material acted upon and the extent of the reduction to be effected, but they may be tapered toward and from the point of nearest approach as is common in apertured dies forwire drawing.

In the forms above described the two members l0 and H are rotatable about the same axis. It

will be evident that this is not essential as one axis may be laterally offset in respect to the other so that the two members partially but not wholly overlap, as shown in Figs, 3 and 4, and in that event the component of the direction of movement of the die surfaces contacting with the strip will.

be larger lengthwise of the strip and will aid in effecting the endwise movement of the strip. In fact the centers of the two members may be offset to such an extent that the component of movement of the engaging parts of the die surfaces with the strip will be suiTiciently large to require no tension to be applied to the strip in pulling it through.

In Figs. 5 and 6, I have shown diagrammatically and in Figs. 13 and 14, certain details of a dinerent form in which the die elements move in straight lines transversely of the strip and in paths disposed in planes at right angles to the strip rather than parallel to it. The die members may be formed of endless strips of hard metal, but in order to secure the desired flexibility and to enable the die members to pass any reasonably small orbits, it is preferred that the die members he made in sections, each section being rigid and non-flexible. As illustrated in Figs. 13 and 14 there are provided a pair of frame members and 2|, each of which supports and guides a die carrier 22. The two die carriers are adjustable toward and from each other by any suitable means, for instance adjusting screws 23. Each die carrier has side walls 24 provided with opposed grooves 25 within which are disposed side flanges or edges of the die members 26. These grooves 25 extend along straight lines to form upper and lower runways for the die members, and these upper and lower runways are connected by substantially circular runways at their ends so that the die members may be arranged in an endless series. The edges of the die members fit comparatively loosely in the grooves, and the grooves are of such width at the curved end sections as to permit the free sliding of the die members.

The die carriers are also provided with runwaysfor a series of roller bearings 21 which engage with the inner or rear surfaces of the die members so as to take the strain exerted on the die members by the drawing of the strip between them. The carriers adjacent to their ends are provided with semi-circular grooves 28 along which the rollers may pass over to a lower runway or vice versa and out of contact with the die members 26.

Each die member intermediate of its side edges and upon the surface opposite to its working surface is provided with a series of teeth constituting a section of a rack bar 29, and mounted in the carrier is a pinion 30 engaging with the rack teeth of the several die sections in succession. The pinion may be rotated in any suitable manner, for instance, it may have a shaft extending through one side of the carrier 26 and provided with a worm wheel 3| engaging with a worm 32. The two worms may be mounted on parallel shafts connected by gearing 33, 34, for simultaneous rotation. The pinions for the two die elements are preferably disposed adjacent to oppositeends of the orbital paths, and the direction of rotation is such that each pinion pushes its corresponding die elements transversely of the path of movement of the strip A rather than pulling it. -Thus the series of die elements are pushed transversely of the strip and in opposite directions, one moving across the upper surface of the strip, and the other across the lower surface. By means of this arrangement there may be a slight amount of play or lost motion between the die members as they pass along their non-working runways or in passing to or from the working runway, but the resistance to the endwise movement of the die members as they move across the strip willcause them to firmly abut without any space therebetween during the portion of their movements where they engage with the strip. The portions of the die members directly engaging the strip are preferably flat and parallel.

The strip may be supplied to and taken from the apparatus in any suitable manner. Merely as an example I have shown the strip withdrawn from a roll B and the thinner strip wound up on a roll C.

The construction illustrated in Figs. 15, 16 and 17 is similar in principle to that shown in Figs. 13 and 14. Instead of having a separate set of rollers 21 for backing up the die members these members may be mounted upon oppositely disposed endless chains. In Figs. 15 and 16 there are shown two pairs of sprocket wheels 40 and endless chains including links 4| secured to the die members 42 and connecting links 43, the links being secured together by pins 44. The die elements 42 are quite similar to those shown in Figs. 4 and 5 and comprise rigid blocks which may be of tungsten carbide, hardened steel, an alloy or other material.

Encircled by each endless chain are frame elements 45 which present surfaces resisting movement of the endless chains away from each other along the portion of their paths. The two endless chains with their series of die elements are rotated in such directions that the die elements in engaging with opposite sides of the strip A travel in opposite directions. Merely as an example of operating means, one sprocket of each chain is connected to a worm wheel 46 engaging with a worm wheel 41, and the shafts of these worm wheels are provided with sprockets 48 connected by chains 49 to sprockets on a drive shaft 50.

One of the frame elements may be adjusted toward or from the other to vary the spacing between the opposed parallel series of die elements, in any suitable manner. Merely as an example, screw rods 5| extend downwardly through the frame into the upper adjustable frame element 45, and these screw rods at their upper ends are provided with worm wheels engaging with worms 52 on an adjusting shaft 53. By rotating this shaft the upper frame element 45 may be raised or lowered to provide the spacing desired.

To resist the movement of the die elements in the direction of movement of the strip being drawn, the chains may engage with opposite sides of a fiange 55 on the frame, or the die elements may be provided with flanges 56 movable in a groove in the frame element.

In Fig. 7, I have shown the two members in the form of plates 10 and II held against movement away from the strip by roller bearings and mounted for back and forth movement. As shown the members are connected to rods I2, the outer ends of the rods being moved in orbital paths, for

' instance, by eccentrics, cams or cranks I3. These versely of the strip is while in Figs. to 7 and 13 to 17 the component transversely of the strip is 180. In both extremes, the surfaces engaging the strip move in opposite directions.

In Figs. and 11, I have shown a form similar to that of Figs. 8 and 9, except that the members 80a and am are grooved for the drawing of a strip which has a curved surface, such as a round wire Aa. instead of a flat strip.

In the ordinary drawing of wire there is the friction created by engagement of the wire with and movement over the die or drawing surface, and also the resistance to the reduction of the thickness. In my improved process the friction is carried away by the movement of the die or drawing members, and in place thereof there is the energy consumed in moving the die members, but this energy is imparted in the drive of said members and not in the pull on the strip. Thus the pull on the strip is merely that required to reduce the thickness and not that required to overcome friction. This reduction in pull permits a far greater reduction in thickness for the same pulling force than has heretofore been possible. The greater the speed of the members or the greater the transverse component of the movement of the members, the greater is the friction carried by the members instead of the strip.

As an important advantage of my invention the strip may be annealed at the same time it is drawn. The friction developed by the movement of the drawing members in respect to the strip, develops heat, and the amount of this heat may be varied by varying the speed of the members. The heat may be sufficient to merely anneal the strip, or may be suflicient to actually soften the strip and thereby further reduce the pull required to effect the reduction in thickness or diameter of the strip. The power required to effect the friction and consequent heating is all mechanical power applied in effecting the movement of the members, and is not the power exerted on the strip in pulling it.

It will be obvious that various changes may be made in the details of construction and that various other types of apparatus may be employed for carrying out my new process.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. The method of drawing fiat strips which includes non-rotatably passing them between two drawing surfaces dis sed in substantially parallel planes, and moving said surfaces in frictional contact with opposite sides of said strips and in directions having opposite components at right angles to the direction of movement of the strip whereby said drawing surfaces carry away the friction created by the drawing of the strip.

2. The process of drawing a flat strip, which includes non-rotatably passing it between opposed die members, and moving said die members in parallel planes and in directions which have opposite components at right angles to the direction of movement of the strip.

3. The process of drawing a flat strip of metal to reduce the thickness thereof, which includes non-rotatably passing it endwise between drawing surfaces of a pair of opposed die members, and simultaneously moving said drawing surfaces in opposite directions transversely of the direction of movement of the strip and frictionally across the opposite flat surfaces of said strip.

4. The process of drawing a strip to reduce the thickness thereof, which includes non-rotatably passing it transversely between parallel opposed die members rotatable about a common axis at right angles to the plane of the strip.

5. The process of drawing a strip to reduce the 5 thickness thereof, which includes passing it endwise between a pair of die members rotatable in opposite directions and about parallel axes at right angles to the plane of the strip.

6. The process of drawing a strip to reduce the 1 thickness thereof, which includes passing it endwise between a pair of die members, and moving said die members in parallel planes on opposite sides of said strip and in opposite directions and in engagement with opposite sides of the strip during the endwise movement of the strip.

7. The process of drawing a strip to reduce the thickness thereof, which includes passing the strip between a pair of endless series of die elements disposed entirely on opposite sides of said strip and having opposed parallel runs in engagement with opposite sides of the strip and movable frictionally across said sides in directions transversely of the direction of movement of the strip.

8. An apparatus for drawing flat strips to reduce the thickness thereof, which includes a pair of die elements on opposite sides of the path of movement of the strip and spaced apart for the passage of the strip therebetween, and means for continuously moving said die elements frictionally across said strip in planes parallel to the plane of the strip and in directions having opposite components at right angles to the direction of movement of the strip.

9. An apparatus for drawing a strip'to reduce the thickness thereof, which includes a pair of die elements rotatable about a common axis at right angles to the direction of movement of the strip, said elements being disposed upon opposite sides of and in engagement with said strip, and

means for non-rotatably advancing the strip endwise.

10. An apparatus for drawing a strip to reduce the thickness thereof, including two endless series of die elements having parallel spaced runs, means for moving said die elementsalong said runs in opposite directions transversely of the strip, and means for passing the strip endwise between said series of elements.

11. The method of drawing a strip to reduce the thickness, which includes moving the strip endwise between drawing members, and heating the strip to anneal it by moving the surface of at least one of said members in frictional contact with the strip and in a direction having a component transverse to the direction of movement of the strip.

12. The method of drawing a strip to reduce the thickness, which includes non-rotatably moving the strip endwise between a pair of drawing members, and reducing the power required to move the strip endwise by imparting movement to the strip engaging surface of at least one memher in a direction transverse to that of the strip movement in a plane parallel to the surface of the strip in contact therewith.

13. The method of drawing a flat strip to reduce the thickness thereof, which includes nonrotatably moving the strip endwise between a pair of drawing members, and continuously moving the engaging surfaces of said members in directions having components at right angles to the path of movement of .the strip and opposite to each other during said endwise movement of the strip,

14. The method of drawing a flat strip to reduce the thickness thereof, which includes non-rotatably moving the strip endwise between a. pair of drawing members, and moving said members in opposite directions and transversely across the opposite surfaces of the strip.

AARON SIMONS.

Images