US 3017793 A
Description (OCR text may contain errors)
Jan; 23, 1962 G. H. APPEL 3,017,793
FORMING TOOLS, MACHINES AND METHODS Filed Feb. 16, 1959 3 Sheets-Sheet 1 IO l5 :FLLE E INVENTOR. GERHARD H. APPEL BY i W ATTORNEYS Jan. 23, 1962 G. H. APPEL 3,017,793
' INVENTOR. ET GERHARD H. APPEL .5 BY
ATTORNEYS Filed Feb. 16, 1959 Jan. 23, 1962 G. H. APPEL 3,017,793
FORMING TOOLS, MACHINES AND METHODS 3 Sheets-Sheet 3 INVENTOR.
GERHARD H. APPEL BY E g ATTORNEYS United States att 3,017,793 Patented Jan. 23, 1962 3,017,793 FORMING TOOLS, MACHINES AND METHODS Gerhard H. Appel, Belle River, Ontario, Canada, assignor to Appel Process, Ltd., Oshawa, Ontario, Canada Filed Feb. 16, 1959, Ser. No. 793,490 1 Claim. (Cl. 78-403) This application relates to and methods.
The art is aware of, and in my prior patent of United Kingdom No. 768,834 of 1957, as well as in my prior French Patent No. 1,074,439 of 1953 and 1,137,761 of 1957, I disclose a forming machine for feeding an elongated workpiece intermittently and longitudinally through a die throat defined by dies which are held fixed against travel in or contra to the direction of feed and are forced intermittently and radially or transversely against the increment of workpiece in the throat, with the dies being inhibited against rotation relative to the workpiece while they are in loaded contact with it. The transverse die actuation is in offbeat relation to the feed of the workpiece so that the workpiece is stationary while being worked on by the dies and is free of the die loads while being fed through the die throat.
The art is also aware that such machines may be used for forming tubular workpieces on a mandrel inside the workpiece, and in prior applications of the United States, Ser. No. 523,598, filed July 21, 1955, now Patent No. 2,857,791, and Ser. No. 561,446 filed January 26, 1956, now abandoned, I disclose how a mandrel may be mounted within a tubular workpiece and held in the machine while the workpiece is fed intermittently and incrementally through the die throat along the mandrel so that the portion of the workpiece in the die throat is worked upon by the dies and radially forced against the portion of the mandrel that is also in the die throat.
The invention hereof relates to an improved apparatus and method based generally upon the foregoing but differing therefrom in certain respects, among which and principally is the formation of the mandrel or tool for obtaining certain desired results which will hereafter appear.
Experimentation with the machines of the foregoing patents and applications has suggested tome that using such machines in accordance with the method and the novel mandrel hereof, it is possible to profile the workpiece intern-ally in a far more effective and accurate manner than has heretofore been the case. It is therefore an object of the present invention to provide a method and an apparatus and a tool or mandrel for profiling the interior of a tubular workpiece to the profile that is desired and that is determined by the profile of the mandrel, with a high degree of accuracy.
Further, it is an object of this invention to provide a mandrel which has longitudinally extending profiling grooves therein for forming longitudinally extending profiling ribs on the interior of the workpiece, with the grooves being gradually and progressively deeper measured along the length of the mandrel and in the direction of feed of the workpiece on it.
Referring back again to the foregoing mentioned patents and applications, it has generally been the practice to compress the workpiece upon a profiled mandrel by external forces applied radially inwardly in the hopes of internally profiling it to the contour of the mandrel grooves, but in the methods heretofore known the results have been that the pressures required for the final part of the operation of forcing workpiece material into the mandrel grooves are considerably greater in magnitude than the forces required in the initial part of the operation. In the present method, the forces are of the same forming tools, machines,
amplitude at the beginning as well as at'the end of the profiling operation.
Further, although it is theoretically possible to profile workpiece material exactly to the contour of the mandrel profiling grooves, as a practical matter, using the methods heretofore known, this is impossible and the net result is that the profiling ribs of the workpiece, even at the end of the operation, using known methods, are not of the exact contour of the profiling grooves of the mandrel. In methods heretofore used, the workpiece material was progressively worked upon in such a manner that at the initial part of the operation, only a very rough approximation of the mandrel grooves was obtained in the profiling of the workpiece and as the operation continued, the approximation became closer on closer but never reached a very high degree of identity of the shape of the workpiece profiling ribs to the contour of the mandrel profiling grooves.
The present method, apparatus, and mandrel are such that at the very beginning of the operation, the workpiece is profiled with ribs of the exact contour of that part of the profiling grooves of the mandrel presented to the workpiece at that moment, and as the operation continues, that con-tour, once established at the beginning of the operation, is maintained and preserved and not changed. The only change is in the depth of the profiling ribs of the workpiece, the depth increasing as the operation continues, but the ribs, once and initially formed to the contour of the mandrel grooves, are confined within such grooves and remain of that contour, even though such ribs are gradually increased in depth as the operation continues.
The foregoing result is obtained largely by the use of a mandrel having profiling grooves which extend longitudinally of the mandrel and which gradually increase in depth so that measured along the mandrel in the direction of feed, the profiling grooves of the mandrel are progressively deeper and deeper, with the result that as the operation continues, the profiling ribs of the mandrel are progressively greater in radial dimension though of the same contour at the end of the operation as at the beginning.
In addition to all of the foregoing the invention hereof contemplates as an additional feature a two step operation of profiling a workpiece with both steps taking place successively and in the same operation. The second step is as previously described, the profiling of the workpiece on a mandrel having grooves of gradually increasing depth. The first step, which precedes the second step, is the improvement of the internal surface of the workpiece on the same mandrel and in the same operation so that by the time the workpiece reaches the grooves of the mandrel at the point where these grooves are most shallow the internal surface of the workpiece has been substantially improved. This is obtained by incorporating within the mandrel and preceding the grooved portion are ungrooved or smooth portion against which the workpiece is radially compressed by the dies as it feeds along such smooth portion, the latter operating to improve the internal surface particularly as to roundness and smoothness and freedom from cracks, scale pits, soft spots, and so forth whereby the internal surface is in a highly improved condition as In these drawings:
FIG. 1 is an exaggerated diagrammatic cross-section view of a tubular workpiece with the mandrel contained therein. 7
FIG. 2 is an end view of a formed workpiece.
FIG. 3 is an end view as if on line 33 of FIG. 1 showing the mandrel only.
FIGS. 4-7 are step-by-step views showing the operation of profiling a workpiece upon a mandrel according to the invention hereof.
FIG. 8 is an elevation view of a cylindrical mandrel.
FIG. 9 is an end view as if on line 9-9 of FIG. 8.
At the outset, it is pointed out that intermittently and incrementally feeding and moving a workpiece along a mandrel held stationary in a die throat and means for so feeding and moving a workpiece longitudinally through a die throat are old and well-known to those skilled in the art. Likewise the art knows of the oif-beat relation between feeding strokes and forming strokes of the dies.
A large variety of workpiece feeding means and moving means are available to the skilled machines designer. Likewise, a large variety of control arrangements are available to enable him to determine exactly what feed and advancing movement of workpiece he desires at any given moment. Likewise, a large variety of holding arrangements are known and available to him to enable him to move a workpiece also in a die throat and to hold a mandrel in a workpiece also in a die throat.
Hence, no effort is made here to illustrate the workpiece feeding and moving means.
The invention concerns itself primarily with a form of mandrel to be incorporated in a forming machine made according to any or all of the foregoing patents and applications, and likewise to a method and apparatus comprising a feed and movement of a workpiece along the mandrel through the throat of the forming machine using a mandrel made in accordance with the invention and illustrated herein.
The problem is simply a desire to profile a workpiece 10 internally, as for example to form it with internal splines or ribs 11, as shown in FIG. 2.
FIG. 1 shows a mandrel 20 which can be used in the method hereof and employing the apparatus hereof to profile the workpiece internally as will later appear. The mandrel 20 has a chucking or holding portion 21, and an ungrooved portion 22 all of which are conventional, the portion 22 being provided to assist in the heat treating of the mandrel.
The mandrel also has a portion 23 which is also ungrooved.
The mandrel also has a working portion 24 longitudinally extending which has grooves 15 which are progressively and gradually deeper. Thus, at the left hand end of portion 24.0f the mandrel, the grooves begin to form, the depth of the groove at such portion being inch. On the other hand, at the right end of portion 24, the grooves are of maximum depth.
Finally, the mandrel has a portion 25 which is an idle portion or relief portion beyond the working area of the dies, and has die grooves continuing the grooves 15 of portion 24.
The dies encompass a portion 30 of the mandrel, which includes portion 23 and 24 of such mandrel.
There are several dies, at least three, and generally four in the preferred form of the machine. The dies are arranged to move radially only, or at least radially only during their working strokes, and are inhibited against other movements, particularly rotary movements while they are in loaded contact with the workpiece. The latter is a major requirement of this sort of machine, namely, that while the dies are in loaded contact with the Workpiece, the dies move radially only and do not rotate relative to the workpiece.
Means not shown, but well within the skill of the trade and disclosed in the previously mentioned applications 4 are provided for intermittently moving the tubular workpiece from left to right along the mandrel and through the die throat in minute increments in rapid succession.
Means are also provided for successively and rapidly moving the dies inwardly under great pressure.
Means are also provided for synchronizing feed movements of the workpiece and the forming movements of the dies in such a way that they are in off-beat relation, the dies not being in loaded contact with the workpiece while the workpiece moves forwardly, and likewise, the workpiece being stationary while the dies move inwardly.
Only for purposes of better illustration, and with no thought of limitation, we here give specific dimensions of one form of workpiece and mandrel.
The workpiece is to be formed to an ID. of 2,000 inches with four spline ribs at each .248 inch deep and extending for four inches.
Hence the mandrel is formedwith four grooves 15, 90 apart.
Portion 22 of the mandrel is cylindrical and slightly over 2 inches O.D. Portion 23 is 1 inch long and has a taper of .001 inch of diameter per inch of length and its dimensions vary from 2.005 inches at the left end of portion 23 to 2.004 inches at the right end of portion 23.
Portion 24 is 4 inches long and is of the same taper, .001 inch of diameter per inch of length, and thus varies from a diameter of 2.004 inches to 2.000 inches. Portion 25 is of the same taper and is 1 inch long and thus varies from a diameter of 2.000 inches to 1.999 inches.
Grooves 15 which start at the left end of portion 24 and continue to the right end of portion 25 have a taper of 0.125 inch of diameter per inch of length and thus these grooves are of zero depth at the junction of portions 2324, having a diameter of 2.004 inches, and at the right end of portion 24 they have a depth of 0.248 inch, and a diameter of 1.504 inches and at the right end of portion 25 they have a depth of 0.310 inch and a diameter of 1.379 inches.
Thus, where the mandrel body in portion 24 has a diameter reduction of .004 inch, the grooves over the same length have a diameter reduction of 0.500 inch, because the groove taper is many times as great as the mandrel body taper, and the grooves are of gradually increasing depth.
The operation can best be visualized upon reference to FIG. 1. When an increment of the workpiece reaches the left end of portion 23 of the mandrel, its inside diameter is 2.005 inches. When it reaches the left end of portion 24 (FIG. 4) its inside diameter is now 2.004. inches and there are no ribs or splines formed in it.
When such increment moves one inch along portion 24 of the mandrel body, which is the working portion, (FIG. 5) its inside diameter has been reduced .001 inch down to 2.003 inches. Meanwhile, however, a rib or spline had been formed in such workpiece increment to a depth of 0.062 inch, the diameter now being 1.879 inches.
When the increment moves one inch further along the mandrel body (FIG. 6) the workpiece is reduced in diameter to 2.002 inches, and the ribs or splines are increased to a depth of 0.124 inch with the diameter being reduced to 1.754 inches.
At the end of the portion 24 (FIG. 7) the workpiece inside diameter is 2.000 inches, its ribs or splines are now 0.248 inch in depth with a diameter of 1.504 inches.
However, and this is the most important feature, the rib or spline, even before the time it is .062 inch in height, is of the exact contour of the mandrel groove as shown in FIG. 5 and the rib or spline remains at this exact contour as the workpiece moves along the mandrel, the only change being in the height or depth of the rib or spline as illustrated in FIGS. 5-6-7.
The rib or spline which at the very beginning of the operation takes on the exact contour of the mandrel profiling groove 15 is completely formed except as to its depth or height and from the very beginning is of perfeet and accurate'contour. It is preserved in this way by the fact that it is at all times confined within the groove of the mandrel.
The forces required to transform the workpiece ribs or splines from the shape shown in FIG. 4 to the shape shown in FIG. 7 are no greater than the forces required at the beginning of the operation where the workpiece is transformed from an unsplined, unribbed form shown in FIG. 4 to the partially formed spiines or ribs shown in FIG. 5. The forces are uniform through out the operation, with each step of the operation simply reducing the workpiece diameter and heightening or deepening the ribs or splines but at no time being required to contour the splines.
The functioning of part 23 is important particularly in combination with the function-ing of part 24. Part 23 operates to improve the internal surface of the tubular workpiece so that it is in a high state of improvement and perfection as to roundness, smoothness, freedom from fissures and the like, surface stresses, etc., before the workpiece reaches the beginning of part 24 where the splining operation takes place.
While in the example shown the mandrel grooves are shown as straight grooves in which case the splining of the workpiece will also be straight, it is easy to observe that the invention hereof is particularly useful for spiral rifiing as for example in the case of gun barrels. The mandrel will have its grooves spirally rifled to the desired formation of the spiral rifling of the workpiece. The workpiece is fed along the mandrel intermittently and incrementally but with a spiral-like rotation of the workpiece along the mandrel which is then stationary. The workpiece rotates however only during the feed increments and does not rotate while it is in loaded contact with the dies.
The outside diameter of the workpiece will of course be reduced gradually as the workpiece is formed on the mandrel. This is due not only to such factors as possible compaction of the workpiece material and particularly to the removal of fissures, cracks, pits and scales on the interior surface of the workpiece, but is also due to the change in cross-sectional form of the workpiece die to the formation of the splines and ribs. No outside dimensions are given however, because the outside diameter is not of importance in this connection.
Further by way of example, however, and again with no thought of limitation, we do give the following -di=mensions. Assuming mandrel part 24 to be four inches long, and that splines of 0.248 inch deep are to be formed, and assuming a feed of about 1200 forming and feeding strokes per foot of feed, we end up with the fact that for the four inch length illustrated, 400 feeding strokes, and of course, 400 forming strokes take place. Thus, each increment of splining is one fourhund-redth of 0.248 inch, or is only 0.00062 inch. This illustrates that each increment of the workpiece has its spline formed and displaced a matter of 0.00062 inch on each forming stroke of the dies. Because the amount of displacement and formation of the splines is reduced to such a small amount, it becomes easy to observe how accuracy of the contour of the splines can be established in the first forming stroke, and once so established can be preserved throughout the rest of the splining operation. As previously described, once the first forming stroke takes place and established the contour of the spline to the contour of the mandrel groove, from then on the spline thus formed is preserved in contour throughout the remaining three hundred ninety-nine forming strokes in the example given, always being confined within the mandrel grooves, and with the only change being the radial dimension of the thus formed perfectly contoured splines. In four hundred equal and separate forming strokes the spline is increased in depth 0.00062 inch per forming stroke, ultimately increasing from 0.0 inch to 0.248 inch in depth.
Thus, it will be seen that this applicationdiscloses a method for internally profiling the tubular workpiece. The method comprises forming the workpiece on a grooved mandrel which is stationarily positioned in a die throat. The mandrel, it is understood, has grooves which are of a gradually increasing depth. The method comprises a step of incrementally feeding the workpiece along the mandrel with the feed starting at the point Where the grooves are most, deep. The method results in forming the workpiece on the mandrel by applying external radial forces to the workpiece in, rapid succession and inoff-beat relation to the feeding of the workpiece in a manner whereby the workpiece is first internally profiled by the formation of ribs therein of the exact contour of the mandrel grooves. Thereafter, the ribs are increased in radial dimension only while they are seated in and confined in and moved along the mandrel groove. The ribs remain of the contour first formed by being confined in the mandrel grooves. Each increment of the workpiece as it is fed along the mandrel is progressively and successfully forced by the die forces into successively deeper portions of the grooves as it moves along the mandrel.
It is also understood that the mandrel grooves extend longitudinally of the mandrel. In the example shown, they are straight grooves to form straight splines or ribs, but this is not required. All that is required is that the grooves extend longitudinally along the mandrel and they may deviate from a straight line as desired.
It will also be understood that there is shown here an apparatus which includes a grooved mandrel whose grooves are of a gradually increasing depth. If the mandrel is tapered, then the grooves are of a greater taper than the mandrel body. The apparatus includes means not shown in the drawing hereof, but incorporated hereinto by reference, for incrementally feeding a tubular workpiece along the mandrel. The means operates in a manner to start the feed at the point where the grooves are most shallow and to continue the feed to and beyond the point where the grooves are most deep. The apparatus also includes the dies which are outside the workpiece and which encompass the mandrel and its grooves. The dies are provided with means whereby they may be moved radially inwardly in off-beat relation to the feed of the workpiece. The dies are mounted in a manner whereby they are inhibited against relative rotation with respect to the workpiece while the dies are in loaded contact with the workpiece.
Finally as a novel element, there is disclosed here a mandrel having longitudinally extending profiling grooves, with the depth of the grooves increasing progressively.
While the mandrel hereof is described in conjunction with the process and apparatus of my prior patents and applications, its use is not limited to forming by such methods and apparatus, but is of more general application and utility, being useful in a variety of forming methods and apparatus, including such, for example, as rotary swaging, etc.
FIGS. 89 show a cylindrical mandrel 120 having a shank or chucking portion 121, an ungrooved cylindrical heat treat portion 122, an ungrooved cylindrical preliminary forming portion 123, a cylindrical portion 124 hav ing tapering grooves of gradually increasing depth, a relief portion 125, all for use with a machine whose dies encompass portion 130, comprising portions 123-124- 125. The parts hereof all corresponding to the .parts numbered 20-30, and 15 of the mandrel of FIGS. 1-3 except for the absence of taper in part 130.
Now having described the method, apparatus and mandrel herein disclosed, reference should be had to the claim which follows.
A mandrel having a longitudinally grooved working portion whose grooves extend the entire length of the working portion; each groove being of uniform width throughout its lengths; each groove being uniformly in- References Cited in the file of this patent UNITED STATES PATENTS 2,641,822 Sampson June 16, 1953 2,810,185 Simons Oct. 22, 1957 10 2,852,835 Harvey et a1 Sept. 23, 1958 8 Ramsay Feb. 10, 1959 Braatz Dec. 22, 1959- FOREIGN PATENTS Australia Mar. 8, 1944 Belgium Feb. 28, 1953 Germany July 3, 1958 Germany July 3, 1958 Great Britain J an. 29, 195 8 Great Britain July 2, 1958 France Mar. 17, 1954