US 2766559 A
Description (OCR text may contain errors)
Get. 16, 1956 w. I. PIXLEY APPARATUS FOR MANUFACTURE OF sxsw ROLLS 2 Sheets-Sheet 1 Filed May 27, 1954 Oct. 16, w -plx Y v APPARATUS FOR MANUFACTURE OF SKEW ROLLS Filed May 27, 1954 2 Sheets-Sheet 2 FIG .3.
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IA" k APPARATUS FOR MANUFACTURE OF SKEW ROLLS William I. Pixley, Huntleigli Village, Mo.
Application May 27, 1954, Serial No. 432,777
2 Claims. (Cl. 51-33) This invention relates to apparatus for manufacture of skew rolls.
The object of the invention is the provision of apparatus for making improved rolls for burnishing, sizing and straightening, wherein the rolls will have a fine finish without the introduction of tool marks at inflexion circles on the rolls.
In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated,
Fig. 1 is a diagrammatic elevation of one form of skew roll made according to the invention;
Fig. 2 is a view similar to Fig. 1, showing another form of roll;
Fig. 3 is a plan view of apparatus for constructing rolls such as shown in Figs. 1 and 2;
Fig. 4 is a right side view of Fig. 3, parts being broken away;
Fig. 5 is a cross section taken on line 55 of Fig. 3; and,
Fig. 6 is a fragmentary diagrammatic view of parts of Fig. 3, showing on a reduced scale an alternative form of the invention.
Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.
Bar and tube straightening machines employ skew rolls of various types and arrangements. For example, on so-called two-roll straighteners, one roll is concave (i. e., of hourglass shape) and the opposite roll a straight cylinder or a convex roll (the latter barrel-shaped). A common characteristic of such arrangements is the production of comparatively narrow bands of cont-act between the workpiece and the end of the concave roll, the workpiece in effect spanning the center portions of the concave roll and bearing on its end margins. This has the efifect of rolling a helical blemish (mark or indentation) in the workpiece, assuming that the workpiece is deflected enough in the rolls effectively to straighten it. The concave rolls have heretofore been made with waists of circular axial curvature, compound circular axial curvatures and hyperboloid axial curvatures. The hyperboloid forms have produced the least damage on workpieces of low-carbon steel having low yield points where no great deflection or bending of the workpiece is required in order to straighten it. Nevertheless such hyperboloid forms have been no more successful than the circular forms on certain alloy bars having low moduli of elasticity requiring a comparatively greater deflection per unit of length for straightening. Thus it will be clear that the prior roll forms have not given suflicient support to the workpiece in the central planes of the rolls to prevent damage under all circumstances to the workpiece surface.
In the cast of co-called multi-roll straighteners, wherein all rolls are of concave form, each roll acts as a support for the workpiece and no bending of the workpiece is done by end reactions from any one roll. To provide the Z,766,55 Patented Oct. 16, 1956 proper support the angles of the rolls are varied in amounts depending upon the size of the workpiece. However, here again the roll forms above mentioned do not give altogether satisfactory support, because the curvatures are such that if the angle between rolls is varied to utilize the full roll length, the workpieces again contact the roll ends, thus as before raising the workpiece from and spanning the roll center portions, thus introducing said spiral blemishes.
By means of the present invention, there is produced a concave type of roll which may be used with another one like it or with a convex roll without the production on the workpiece of any spiral blemishes. Briefly, this is accomplished by a concave roll having an axial curvature consisting of a center section of hourglass shape, defined either by a circle or circles of revolution or a hyperboloid of revolution, and two end sections of conical shapes tangent to the respective ends of the surface of revolution of the center section. A modification consists in the provision of in the end sections, reverse curvatures relative to the curvature of the center section, at what will hereinafter he referred to as circles of inflexion.
With reference more particularly to Fig. 1 of the drawings, there is shown at numeral 1 a roll of general hourglass shape having a center section 3 and end sections 5 beyond imaginary circles 7. The roll is of right circular section at all points along its length. The outside of the roll is constituted by a surface of revolution formed around the center line C-L. The intersection of an axial plane containing the center line CL is indicated by a curve 9 which may be a segment of a circle or modified circles. Or the surface may be a hyperboloid of revolution. Thu-s in general the line 9 may or may not have a constant radius of curvature in a plane containing it and the center line .C'L. At its ends the central section, as designated by the circles "7, is tangentially continued by conical shapes which constitute the end sections 5. The axes of the conical ends '5 are coaxial with the axis of the surface of revolution forming the center section 3. This arrangement places the tangent surfaces of the end sections 5 within any surfaces of revolution which would be formed by extension of the shape 9 beyond the circles 7. These circles 7 are hereinafter therefore designated as tangent inflexion circles. They cannot be seen on the rolls (as in the drawings) but exist thereon.
In Fig. 2 an alternative form of roll is shown, in which like numerals designate like parts and features. Primed numerals indicate similar parts with variations disclosed below. Thus in Fig. 2, the numeral 3 again represents an hourglass central section such as above described. Curve 9 may be constituted by a circle or a hyperboloid, as above described. But the end section 5', instead of being extended by means of tangent conical shapes as indicated by the dotted lines 11, are extended by tangent barrel-shaped surfaces of revolution. These surfaces are generated by curves 15 of reverse curvature relative to that of line 9 but respectively tangent thereto at inflexion circles "7. Thus all of the material in each barrel-shaped end section 5 is positioned inside of an imaginary cone 11, extending tangentially from the center section 3. The lines 15 generating the surfaces of revolution of the end sections 5' may be of any suitable form, and throughout their length may or may not have a constant radius of curvature, as is indicated. But in any event, the curvature is reverse to that of section 3.
An advantage of skew rolls such as described above is that the curvature of the center section 3, whatever it may be, is not carried on into the end sections 5 or 5'. At the inflexion circles this curvature becomes either infinite, i. e. straight (Fig. 1) resulting in end cones 5 which are straight-sided or reversed (Fig. 2). The result is that the contact area between the center section of the roll and workpiece will be increased materially. Thus the workpiece, instead of pressing with a large force on the roll ends or spanning section 3, will tend better to be supported throughout the entirelength oi the rolls. .Thus localized blemishing pressures are minimized. This is true whether two concave rolls are used or whether one concave roll is used in connection with another barrelshaped roll.
Another advantage is that the rolls may be designed with deeper curvatures, resulting in the ability to effect greater bending or deflection of the workpiece, particularly in the case of two-roll straighteners. The greater and more even contact afforded by the invention produces better burnishing, sizing and polishing effects without blemishes and with .a longer roll life. Moreover, the rolls have a greater capacity because extremely high local end loading pressures are eliminated. it is these high end pressures that also tend to cause the stated blemishes.
In Figs. 3 and 4 apparatus is illustrated for carrying out an improved method for making rolls of the class herein described. The Fig. 1 form of roll is shown, for example, in Fig. 3 and numbered accordingly. This is mounted on bearings 17 and rotated by means of a suitably belted sheave 19 around center line CL. At 21 is shown a stationary base plate or support in which is an array of openings 23, the center lines of which are located in a plane N normal to the center line CL, the plane passing through the narrowest portion of the waist of the roll. These openings 23 are for the selective reception of a pivot pin 25. On the plate 21 is located a swinging carriage 27 in which is a similar array of openings 29 in alignment with the openings 23. Thus by replacement of the pin 25, various points of pivoting may be obtained between the carriage 27 and the base plate 21.
The carriage 27 may be swung by means of a link 31, operated by a double-acting hydraulic piston 33 in a hydraulic cylinder 35, pivoted to plate 21 at 37. Parts 31, 33, 35 form cooperating cylinder and plunger elements, one of which is pivoted to the support 21 and the other of which is pivoted to the swinging carriage 27.
On the carriage 27 are dovetail guides 39 for a tengentially movable carriage 41. This carriage is operated by a piston rod 43, pivoted thereto at 45 and reaching to a double-acting hydraulic piston 47 within a hydraulic cylinder 49. The latter is pivoted at 51 to an extension 53 from the carriage 27. Parts 43, 47, 49 form cooperating cylinder and plunger elements, one of which is pivoted to the carriage 27 and the other of which is pivoted to the carriage 41.
On the carriage 41 are radial guides 55 for a radially movable carriage 57. This carriage is pivoted at 59 to a piston rod 61, reaching to a double-acting hydraulic piston 63 within a hydraulic cylinder 65. The latter is pivoted at 67 to an extension 69 from the carriage 41. Parts 61, 63, 65 form cooperating cylinder and plunger elements, one of which is pivoted to the carriage 41 and the other of which is pivoted to the carriage 57.
The carriage 57 carries bearings 71 for a spindle 73 of a grinding wheel 75. The carriage 57 also carries a motor M, having a belt drive 77 connecting it with the spindle, so that the grinding wheel 75 may be driven from the motor. As will be seen from Fig. 3, it is preferable that the mid section of the roll 1, the central plane of the grinding wheel 75, and the plane N containing the center lines of the holes 23 and 29, shall be coincident. The axis A of the grinding wheel is parallel to the direction of movement of carriage 41. The motion of carriage 41 is tangential to the swing of carriage .27.
Suitable hydraulic fluid lines, valves and valve controls (not shown because known) are employed to lead hydraulic fluid to and from opposite sides of the pistons 33, 47 and 63. Thus control may be had or" the movements of the carriages 2'7, 41 and 57. 7 It will be understood that hydraulic actuation of these parts is only one type of apparatus for driving them, and that other ap- 4 paratus may be used, such as mechanical linkages, or they may under certain circumstances be controlled manually.
Operation is as follows:
Assuming the parts to be in the Fig. 3 position, the motor M being driven and both the roll 1 and grinding wheel 75 rotating, the rotary carriage 27 may be swung on both sides of the plane N so as to grind section 3.
The effective grinding portion of the wheel 75 may be moved to either point 13 on either inflexion circle 7. The effect is to grind the hourglass section 3 with a partial circle 9 functioning as a generating curve for the rcsulting surface of revolution.
Next, assume that the surface of section 3 has been properly ground, and the wheel 75 brought, say, to the lefthand point 13 by action of the mechanism 31, 33, 35, 37. When point 13 is reached by the mid plane of wheel 75, action of said mechanism is stopped. Fluid is then admitted behind piston 47 to drive the carriage 41 along guides 39. This will result in tangential movement of this carriage, resulting in grinding of the conical left end portion 5. The mid plane of wheel 75 is then tangentially returned to touch at the left-hand point 13 and further tangential movement of carriage 41 is stopped. Plate 27 is then swung so that the wheel 75 traverses section 3 and arrives at the right-hand point 13. Then fluid is admitted to the left of piston 47, thus driving the carria e 41 tangentially to the right in guides 49 and grinding the right-end portion 5. The result is a smooth, continuous, unbroken ground surface forming on the roll 1, consisting of the central hourglass portion 3 and tangential endwise cones 5, connected at the inflexiou circles 7. For successive sweeps of the wheel 75, as above described, carriage 57 may be moved radially outward until a desired roll size is obtained. Hydraulic control of piston 63 in cylinder 65 is used for this purpose.
The carriage 57 may also be moved by means of piston 63 in order to modify the generated surface of section 3. Thus, for example, it a hyperboloid of revolution is to be formed in this region, hydraulic fluid may be automatically metered into and out of cylinders 35 and 65, so as to modify the circular curvature as carriage 27 swings. The reverse curvatures of the end sections 5 of Fig. 2 may also be efiected by automatically controlled admission and exhaust of hydraulic fluid into and out of cylinders 49 and 65, which occurs while carriage 27 is stationary at the ends of its swing.
In view of the above, it will be seen that the apparatus described constitutes a convenient means for carrylog out my new method of grinding the roll forms. It will be seen that this method briefly constitutes: first, providing a guide for the movement of grinding wheel 75- which will permit its axis A to be located substantially parallel to the center line CL of the roll 1 and pivotally swung into angular positions relative thereto; second, providing for tangential movement of the grinding wheel along its own axis A at a time when A is nonparallel to the axis CL; third, providing change of radial movements of the axis A to and from the pivot point at 25 for modifying the curvature of the section .3 or of the sections 5 or 5; and fourth, providing for diiferent grindingradii by changing the position of the pivot point at .25. or adjusting the radial position of carriage 57 on carriage The advantages of the mechanical apparatus per se arev that it is simple to construct and easy to operate, so as to produce a continuous, unbroken surface between sections 3 and 5 or 3 and 5' at the inflexion circles 7. The apparatus is also adaptable to various types of mechanical, hydraulic or manual control.
It will be understood that, while the apparatus described controls the motions of the grinding wheel 75, the same apparatus can be used for controlling an edge cutting tool 81 supported in a tool post 83 mounted on carriage S7, for shaping rolls prior to grinding (see Fig. 6). In
such case the speed of rotation of the roll blank is reduced.
As regards the skew roll form, the invention in its broadest aspect is characterized in that a central section of the roll has flaring ends and flaring end sections having tangential connections with said central section, no point on the surface of either end section lying outside of the tangential conical projection from the respective flaring end of the central section. For example, in Fig. 2, all points on the end sections 5' lie within the tangential conical projections 11. In the case of Fig. 1, no point on either end section 5 lies outside of such a projection, since all of such points lie on such a conical projection.
In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.
As various changes could be made in the above without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be inter support, means for rotating the skew roll on a horizontal first axis which is fixed relative to the support, carriage, a first changeable-radius pivot means between the carriage and the support, means for swinging said first carriage on said pivot means comprising a cylinder and a plunger element therein, one of which is pivoted to the support and the other of which is pivoted to the first carriage, a first guide on the first carriage, a second movable carriage in said first guide, said first guide being formed to direct movement of said second carriage substantially tangentially with respect to a radius from said pivot means, means adapted to move the second carriage in said first guide comprising a cylinder and a plunger element therein, one of which is connected to the first carriage and the other of which is connected to the second carriage, a second guide on the second carriage, a third movable carriage in said second guide, said second guide being formed to direct movement of said third carriage substantially parallel to said radius, means adapted to move said third carriage in said second guide comprising a cylinder and a plunger element therein, one
of which is connected to the second carriage and the other of which is connected to the third carriage, and a member supported upon said third carriage extending therefrom into machining engagement with said roll.
2. Apparatus for machining the surface of a skew roll blank for roll straighteners and the like, comprising a support, means for rotating the skew roll on a horizontal first axis which is fixed relative to the support, a first carriage, said support and the carriage having pairs of registered pivot openings, a pivot pin selectively insertible into any registered pair, means for swinging said first carriage on said pivot pin comprising a cylinder and a plunger element therein, one of which is pivoted to the support and the other of which is pivoted to the first carriage, a first guide on the first carriage, a second movable carriage, in said first guide, said first guide being formed to direct movement of said second carriage substantially tangentially with respect to a radius from said pivot pin, means adapted to move the second carriage in said first guide comprising a cylinder and a plunger element therein, one of which is connected to the first carriage and the other of which is connected to the second carriage, a second guide on the second carriage, a third movable carriage in said second guide, said second guide being formed to direct movement of said third carriage substantially parallel to said radius, means adapted to move said third carriage in said second guide comprising a cylinder and a plunger element therein, one of which is connected to the second carriage and the other of which is connected to the third carriage, and a member sup ported upon said third carriage extending therefrom into machining engagement with said roll.
References Cited in the file of this patent UNITED STATES PATENTS 209,588 Seaman Nov. 5, 1878 1,489,922 Brundage Apr. 8, 1924 1,756,908 Baumberger Apr. 29, 1930 1,832,631 Hartley Nov. 17, 1931 1,859,851 Stiefel May 24, 1932 1,941,593 Cleveland Jan. 2, 1934 1,980,444 Scott Nov. 13, 1934 2,290,051 Hinkley July 14, 1942 2,302,712 ONeill Nov. 24, 1942 FOREIGN PATENTS 841,112 Germany June 13, 1952