US 3822622 A
An apparatus for punching annular parts from a sheet of stock material, such as a continuous ribbon or tape of plastic material. The apparatus comprises means for feeding the ribbon or tape of stock material between two plate members, clamping a portion of the ribbon or tape between the plate members, and, by means of a pair, or a plurality of pairs, of opposed punch members adapted to be reciprocated in timed relationship to firstly punch from the stock material a slug for forming the center aperture of the annular part, and secondly punch from the stock material the annular part itself. The slug punched from the stock material and the annular part are separated by appropriate aspirator means.
Description (OCR text may contain errors)
United States Patent 1191 Smith et al.
1111 3,822,622 1451 July 9,1974
[ APPARATUS FOR MAKING ANNULAR PARTS  Inventors: Joseph E. Smith, Birmingham;
Raymond P. DeSantis, Royal Oak;
Georges D. Detroyer, Grosse Ile, all of Mich.
 Assignee: Wolverine-Pentronix, Inc., Lincoln Park, Mich.
 Filed: Aug. 7, 1972 21 App]. No: 278,532
 US. Cl 83/100, 83/214, 83/621, 83/623  Int. Cl B26f l/02 Field of Search 83/621, 623, 100, 380, 83/214; 10/72 R, 85
 References Cited UNITED STATES PATENTS 2,313,525 3/1943 Edelman 83/621 X 3,568,554 3/1971 Wieche 83/621 X 3,610,082 10/1971 Riggi et a1 83/623 X 3,640,167 2/1972 Axtmann 83/623 X FOREIGN PATENTS OR APPLICATIONS 1,050,322 12/1966 Great Britain 1. 83/621 France 1. 83/621 France 83/621 Primary Etaminer-J. M. Meister Attorney, Agent, or Firm-Hauke. Gifford, Patzilidis A: Dumont 5 7] ABSTRACT An apparatus for punching annular parts from a sheet ofstock material, such as a continuous ribbon or tape of plastic material. The apparatus comprises means for feeding the ribbon or tape of stock material between two plate members, clamping a portion of the ribbon or tape between the plate members, and, by means of a pair, or a plurality of pairs, of opposed punch members adapted to be'reciprocated in timed relationship to firstly punch from the stock material a slug for forming the center aperture of the annular part, and
secondly punch from the stock material the annular part itself. The slug punched from the stock material and the annular part are separated by appropriate aspirator means.
'15 Claims, 8 Drawing Figures PATENTEU IL I 3.822.622
sum 1 BF 3 FIG! BACKGROUND OF THE INVENTION Very small annular parts such as, for example, magnetic cores are conventionally made of powder material, such as ferrites and the like, which is compacted in an appropriately shaped die cavity, under high pressure by way of a punch adapted to compact the powder material against an anvil closing the end of the die cavity, or between two oppositely advancing punches disposed in the die cavity. A core rod member is disposed in the die cavity for forming in the center of the compacted mass of powder material an aperture, or hole, such that the finished article, or green core, is in the form of an annulus, or toroid.
It has been a general trend in many industries, and more particularly in the electronic and computer industry in which the majority of magnetic cores are used, to miniaturize components, and this has led to many difficulties in forming tiny parts of the order of a few thousandths of an inch in overall size with precision, constant density, and accurate dimensions. The manufacture of magnetic cores requires very close dimensional and density tolerances so as to achieve consistency'in the physical and electromagnetic characteristics of the sintered cores. As the dimensions of magnetic cores are decreased with a view toward such miniaturization of the equipment in which they are used, the result is that a great number of cores may be used within a small frame area and a great number of frames may be packaged within a small volume, which are all desirable achievements not only with a view toward miniaturization but also with a view toward obtaining magnetic cores which can be switched from a magnetic state to another magnetic state in a very short period of time and with a very small control current. However, difficulties are readily encountered in compacting from powder material such minute parts, seemingly not larger to the naked eye than aspeck of dust, with the accuracy required. For that reason, it has been found advantageous to make magnetic cores of very small dimensions, such as 12 mils, 300 microns, or less, in diameter by means other than compacting powder ferrites and like magnetic materials.-
One of the means contemplated for obtaining miniature magnetic cores consists in making a thin sheet of calendered plastic binder containing the appropriate metallic oxides or ferrites in very. fine particles uniformly dispersed in the binder. The stock material from which the magnetic cores are eventually made therefore takes the form of an elongated pliable plastic sheet or film. Preferably the sheet is slitted lengthwise to obtain several continuous ribbons or tapes of a predetermined width, and a few thousandths of an inch in thickness, which may conveniently be spooled, and from which annular parts, forming the green magnetic cores, may be punched out as the stock material is unwound from its spool. The tiny annular parts, or toroids, punched from the ribbon or tape of stock material are subsequently heated at a relatively high temperature so as to evaporate, or burn out, the plastic binder and sintered at yet a higher temperature to form magnetic cores suitable for stringing in an appropriate array in a frame, as is conventionally done. The thickness of the stock material determines the final height of the magnetic cores after sintering, taking in consider-' ation the shrinkage factor during sintering. The composition of the plastic resin binder must be properly selected so as to permit thesintering of the cores without the formation of deleterious ash or residue materials in any appreciable amount having an adverse effect upon the final electromagnetic characteristics of the magnetic cores.
The tooling used for punching the green" cores, or unsintered cores, from the tape of stock material is a very high precision tooling of very small dimensions and close tolerancesfor making such parts which. although hardly discernible with the naked eye. require extreme consistency of dimensions: from one part to another, while permitting the high production rates compatible with an economically viable operation. Al though a conventional progressive die is generally capable of punching annular parts, a progressive die for making parts as small as green magnetic cores requires high precision not only in the dimensions of the separate punch and die elements for first forming the central aperture in the cores and secondly punching the core from the stock material at a position of the stock material separate from that at which the central aperture is punched out, but, more importantly yet, a pro gressive die requires very complex feeding and indexing means for effecting the progressive displacement of the stock material through the die and for accurately indexing the stock material sequentially at at least two separate punching stations for obtaining a single fin ished part. There result considerable difficulties in forming parts with the high dimensional precision and with the high degree of concentricity required for a finished product such as green magnetic cores. Such inconveniences, disadvantages and difficulties are overcome by the apparatus of the present invention which permits to punch the central aperture and the complete annular part at a single punching position during a single stoppage of the stock material progression through the punch and die assembly and by means of concentric punch and die members. In this manner, the required degree of accuracy in dimensions and in concentricity is obtained, which cannot be obtained by way of the prior art punch and die apparatus.
SUMMARY OF THE INVENTION The present invention has therefore for its principal object to make, at high production rates, annular parts of very small dimensions of the order of a few thousandths of an inch in height and width, punched from a sheet of stock material such as, for example, a ribbon or tape of pliable plastic material consisting of a uniform dispersion of solid particles in a binder, by means of a relatively simple apparatus consisting of at least a pair of opposed and concentric punch and die members for forming a completepart from the tape of stock material in a single operation, and to provide simple means for intermittently feeding the tape of stock material between opposed pairs of punches. The appara-- tus of the invention is in a modular [form which permits interchangeability with the tooling normally used on a powder material compacting press for forming parts from compacted powder material which, as will be obvious to those skilled in the art, presents a commercial and technological advantage of great value resulting from an efiicient use of already existing machinery. However, as will also be obvious to those skilled in the art, the present invention may be incorporated in any other machine capable of providing appropriate driving means for the stock material feeding mechanism and for the punch and die members actuating mechanism.
The many objects and advantages of the present invention will become apparent when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a longitudinal sectional view of an example of apparatus according to the present invention;
FIG. 2 is a top plan view of a portion of the apparatus of FIG. 1, as generally seen from line 22 of FIG. 1, and omitting some elements for the sake of clarity;
FIG. 3 is a sectional view from line 3-3 of FIG. 2;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An apparatus according to the present invention, designated by numeral at FIGS. 1, 2 and 4, takes the form of a multiple punch and die unit adapted for mounting on the table of a machine, such table being indicated at 12 in FIGS. 2 and 4. The machine may be, for example, any one of the Multipak (Registered Trademark) powder compacting presses made by the Pentronix Division of WolverinoPcntronix, Inc. of Lincoln Park, Mich., or any one ofthe presses disclosed in US. Letters Pat. Nos. 3,328,840, 3,328,842, 3,344,213, 3,415,142, 3,561,054, 3,561,056, 3,574,892 and 3,645,658, all assigned to the assignee of the present application. The apparatus of the present invention may also be mounted on the table of any appropriate machine provided with either cam actuated or hydraulic actuated upper and lower punch member driving means. For illustrative purpose only, the invention will be described as being adapted for mounting on the table ofa Multipak powder compacting press, or any one of the presses disclosed in the above mentioned patents, instead of the powder compacting punch and die module, or tool set, normally mounted thereon and interchangeable with such powder compacting punch and die module.
The apparatus 10 comprises a base plate 14 mounted over an appropriate aperture in the table 12 and fastened thereon by any convenient means, such as bolts 16. The base plate 14 has on its upper surface a recess 18 in which is mounted a plate member 20, also by means of any convenient fastening means such as screws and the like, not shown. Three column members 22, two of which only can be seen in FIG. 1 are each mounted through an appropriate bore 24 axed at right angle to the upper and lower surfaces of the base plate 14. The column members 22 are fastened in the bores 24 by any convenient means, such as being press-fitted therein, cemented, or held by set screws or the like, not shown. The column members 22 project a certain distance above and below the base plate 14.
Mounted below the base plate 14 there is a punch holder member 26 provided with an enlarged diameter portion 28 having three axial bores 30, each aligned with and defining a linear bearing for one of the column members 22, such that the punch holder member 26 is reciprocable relatively to and below the base plate 14. The punch holder member 26 is provided at its lower end with an actuating stem 32 fastened to a reciprocating means depending from the driving mechanism of the machine (not shown) on which the apparatus of the invention is mounted. The end of the punch holder member 26 disposed toward the base plate 14 has a punch mounting block 34 fastened thereto which is adapted to accept a plurality of lower punch members 36, preferably made of carbide, disposed in two parallel rows, each row comprising several punch members such as, for example, 10, 12, 14 or more punch members in each row, according to the width of the stock material from which finished articles are to be punched and according to the size of the finished articles. Such rows of punch members 36 extend transversely at a right angle to the plane of the sheet of paper on which FIG. 1 is drawn. Preferably the punch members in alternately one row and the other are staggered so as to reduce to a minimum the amount of scrap material remaining in the stock material after the finished articles are punched from the stock material.
The punch members 36 are mounted in appropriate bores 38 in the punch mounting block 34, the coincident axes of each bore 38 and associated punch member 36 being parallel to the axes of the column members 22. The punch members 36 are fastened in the bores 38 of the punch mounting block 34 by an appropriate means such as being press-fitted therein or by being cemented therein. The punch members 36 are hollow, as best shown at FIGS. 58, and are thus provided with an internal bore 40 which is placed in communication with a manifold or collector 42, formed in the punch holder member 26. The manifold or collector 42 is provided at its lower end with an outlet passageway 44 and an appropriate fitting, not shown, to which is connected a flexible line 46 in turn connected to an aspirator means, not shown, such that any particle falling in the manifold or collector 32 may be evacuated.
Part of the base plate 14 is cut-out below the plate member 20 and the plate member 20 has a plurality of bores 48 each slidably accepting therethrough one of the punch members 36 which have normally their upper end constantly engaged in the bores 48.
Above the base plate 14, there is an upper plate 50, as shown at FIG. 1, provided with appropriate through bores 52 each adapted to slidably accept therethrough the upper projecting portion of a column member 22. The upper plate 50 has, on its lower face, a recess 54 in which is mounted a plate member 56, preferably made of a very hard material such as a carbide or the like and fastened therein by any convenient means, and which is provided with two parallel rows of staggered die apertures 58, each of which is axially aligned with one of the bores 48, and consequently one of the lower punch members 36. In the example of configuration illustrated, the plate member 56 has a ridge 60 extending transversely between the two parallel rows of die apertures 58, although the ridge may be omitted. The top surface of the upper plate 50 is formed as a V-shaped recess 62, the apex of which is directed towards the rows of die apertures 58 in the plate member 56. A plurality of tubes 64, each corresponding to one of the die apertures 58 and having its end proximate such die aperture, are clamped by means of clamping blocks 66 on both angled surfaces of the U-shaped recess 62 on the upper plate 50, the other end of each tube 64 being connected by means of an appropriate flexible line to the inlet of an aspirator 68 which may be of the type disclosed in copending application Ser. No. 173,452, now US. Pat. No. 3,768,952, such that each individual article extracted from each die aperture 58 is finally collected in an individual receptacle 70, each individual receptacle 70 corresponding to one of the die apertures 58 so as to segregate the production of each die aperture from the production of every other die aperture.
A platen 72 is disposed above the upper plate 50 and is provided with appropriate bores 74, each adapted to slidably accept one column member 22 therethrough. It is obvious that each bore 74 in the platen 72, as each bore 52 in the upper plate 50, and each bore 30 in the lower punch holder member 26, may be provided, and is generally provided, with an appropriate linear bearing or bushing for the purpose of achieving proper alignment of the elements and low wear and friction during relative reciprocation of the elements when the apparatus is in operation. The platen 72 is further provided, on its lower face, with an upper punch mounting block 76 fastened thereon by any convenient means such as pins and bolts, and the punch mounting block 76 is in turn provided with a plurality of bores 78, disposed in parallel staggered rows, each one adapted to accept an upper punch 80 for rigid mounting thereon by cementing, press-fitting, or any other convenient means. Each upper punch 80 is conveniently made of a cylindrical rod of hard metal or alloy, such as a carbide as tungsten carbide, press-fitted into a tubular cylindrical member 82, for example made of steel, which is in turn press-fitted, cemented or otherwise fastened in the bore 78 of the punch holder block 76.
The bottom end portion, as seen in FIG. 1, of each bore 74 in the platen 72 is countersunk, as shown at 84, and thus forms a recessed annular abutment 86 engaging the upper end of a compression coil spring 88, each coil spring 88 being disposed surrounding one of the column members 22 between the upper annular abutment 86 in the platen 72 and a similar annular abutment 90 formed in the upper face of the upper plate 50 about the bore 52. In this manner, when the platen 72 is displaced downwardly, the resultant compression of the coil springs 88 exert a downwardly directed bias that urges the upper plate 50 towards the base plate 14. Spring means, such as Belleville springs 92, are disposed around each of the column members22 in a pocket 94 formed in the upper face of the base plate 14 to urge the upper plate 50 away from the base plate 14. The strength of the Belleville springs 92 is sufficient to normally support the combined weights of the plate member 50 and the platen 72, and the coil springs 88 in turn supports the platen 72 away from the upper plate 50 in the position represented at FIG. 1. Under those conditions, the plate members and 56 are apart from each other, thus permitting a sheet of stock material 96, preferably in the form of a ribbon or tape of such stock material, to be fed between the plate members 20 and 56 by means of two pairs of opposed feed pinch rolls 98100 and 102-104, mounted respectively on shafts 106-108 and 110-112, ahead and beyond the upper plate 50. After the ribbon or tape of stock material 96 has been advanced between the plate members 20 and 56 by the feed rolls 98100 and 102-104 and stopped, an upper ram member 114, forming one of the drive outputs of the machine on which the apparatus of the invention is mounted, is reciprocated downwardly such as to engage the upper face of the platen 72 and drive the platen downwardly. The downward motion of the platen 72 compresses the springs 88, thus in turn displacing downwardly the upper plate 50 such that a portion of the stock material 96 is finnly clamped between the plate members 56 and 20. The Belleville springs 92 are designed such as to be weak enough to compress sufficiently for allowing a slight downward motion of the upper plate 50 which effects the clamping of the stock material 96 between the plate members 20 and 56. Further downward reciprocation of the ram member 114 causes further downward motion of the platen 72, while compressing the coil springs 88, and the upper punch members are reciprocated through the die apertures 58 in the plate member 56, sequentially with reciprocation of the lower punch members 36 mounted in the lower punch holder 26 by means of the drive output of the machine connected to the punch holder actuating stem 32. The diverse punching operations necessary to form an annular part are thus effected sequentially, as will be explained hereinafter in further detail, at a single position of the stock material. After the punching operations have been effected, the upper ram member 114 is reciprocated upwardly to the position shown at FIG. 1,
such that the stock material 96 is; no longer clamped between the plate members 56 and 20 and is further advanced therebetween by means of the feed pinch rolls 98-100 and 102-104 to a subsequent position presenting a fresh area of the stock material to the action of the punch and die members. The: clamping step and punching operations are then repeated.
FIGS. 5-8 graphically show the successive steps involved in punching a finished part from the sheet of stock material 96. Duringfeed of the sheet of stock material 96 between the plate members 56 and 20, the plate members are separated at least by a distance sufficient to permit advance of the stock material therebetween, as shown at FIG. 5. The end of each lower punch member 36 is substantially flush with, or slightly lower than, the upper end of the aperture 48 in the plate member 20. After the sheet of stock material 96 is clamped in position between the two plate members 56 and 20, the lower punch members 36 are positioned in engagement with the lower surface of the stock material and the upper punch members 80 are advanced through the die apertures 58 in the plate member 56 to the position schematically shown at FIG. 6, causing the end of each punch member 80 to project within the end of the bore 40 of each lower punch member 36, thus piercing the sheet of stock material 96 as a result of cutting out a slug or disc, shown at 116 falling by gravity through the bore 40 in the lower punch member 36, with the formation of a hole or aperture 118 in the sheet of stock material. The slugs or discs 116 of stock material, which are scrap, fall in the manifold 42 (FIG. 1) formed in the lower punch holder 26, and are evacuated by aspiration through the passageway 44 and flexible tubing or line 46.
The upper punch members 80 are subsequently retracted, while the lower punch members 36 are simultaneously, or subsequently, retracted slightly and then advanced upwardly into the die apertures 58 in the plate member 56 to pierce a larger hole 120 (FIG. 7) in the sheet of stock material 96, resulting in the formation of a toroidal or annular-shaped article 122. The annular article 122 is ejected from the die aperture 58 in the plate member 56 as a result of the lower punch 36 being further displaced upwardly to a position (FIG. 8) causing its end to be at least flush with the upper end of the die aperture 58, or preferably slightly projecting therefrom, and the annular article 122 is aspirated through the tube 64. Preferably, to insure that the annular article will separate from the end of the punch 36 to which it may stick, the punch 36 is first reciprocated such that its end projects slightly above the die aperture 58, then retracted within the die aperture to strip the annular article from the punch end, and then reciprocated again to a position whereby its end projects slightly above the die aperture. In the configuration illustrated, the ridge 60 on the upper surface of the plate member, or die plate, 56 acts as a dam preventing each individual aspirator tube 64 from aspirating any annular article other than the one being ejected from the particular die aperture serviced by that aspirator tube. Alternatively, the end of the aspirator tube 64 is shaped as tosurround the upper punch member 80, such that in either configuration the diverse finished articles are appropriately segregated in the containers 70 (FIG. 1), each container collecting only the finished articles originating from a particular die aperture.
In order to use calendering and slitting machines already on the market, for example for making photographic films, it is convenient to adopt a standard width for the ribbon or tape of stock material 96, with the result that the ribbon or tape of stock material is conveniently ofa width such as for example 16 mm, 35 mm, or a like convenient dimension. The stock material, as previously explained, consists ofa plastic film of an appropriate thickness, for example 6 to 10 mils, or 150 to 240 microns, with, for example if it is desired to manufacture magnetic cores, fine particles of magnetic metallic oxides or ferrites uniformly dispersed throughout the mass of the film. Annular articles, such as green" magnetic cores, may be formed by means of the apparatus of the invention with an outer diameter in the range of 20-9 mils, or 500-225 microns, or less with a center aperture or hole in the range of 12-4 mils, or 300-100 microns, or less. Utilizing an apparatus having two rows of 14 die apertures and punch pairs, for example a total of 28 green' cores are punched in the course of a single stroke of the apparatus. The apparatus may be mounted on a machine that drives it, for example, at 700 strokes or more per minute, with the result that the production rate obtained amounts to about 1,200,000 green cores per hour. Because the production originating from each die aperture is segregated from the production originating from every other die aperture, a malfunction associated with one or more die apertures, due to punch breakage or uneven wear of the punches and die walls, may be ignored, as the remaining good cores are separatedfrom the bad cores, until it is convenient to stop the machine for replacing the punch and die assembly of the apparatus of the invention by a new one, or for effecting any maintenance work that may be required.
The intermittent feed mechanism for the tape or ribbon of stock material 96 will now be described in detail, with reference to FIG. 1 and more particularly to FIGS. 2-4. The tape of stock material 96 isnormally spooled on a reel, not shown, conveniently mounted on a reel horse or other convenient means permitting unimpeded unwinding of the tape of stock material 96 from the reel. The leading edge of the tape or ribbon of stock material 96 is manually engaged between the opposed pinch rolls 98 and 100. The roll 98 is mounted above the base plate 14 and is keyed or otherwise fastened to the shaft 106 which is intermittently driven, as will be explained hereinafter. The roll 100, disposed below the level of the upper face of the base plate 14, in a cut-out portion thereof, is constantly urged by way of a spring bias towards the driven feed roll 98 so as to apply the upper face of the tape of stock material 96 against the peripheral surface of the feed roll 98. Sub sequent advance of the tape of stock material through the apparatus is, prior to and after the leading edge of the tape reaches the feed pinch rolls 102-104, effected automatically during the operation of the apparatus, by means of both the pairs of feed pinch rolls 98.-100 and 102-104, in appropriate timed relationship with the reciprocation of the upper and lower punches and 36 during the period of time when the plate members 20 and 56 are urged away from each other as a result of the upper plate 50 being supported by the Belleville spring 92. The structural arrangement of the pairs of pinch rolls 98-100 and 102-104 is the same, the only difference being that the periphery of the feed roll 98 is smooth so as not to mar the surface of the stock material 96, while the periphery of the feed roll 102, which engages the tape of perforated scrap material proceeding from the punching apparatus of the invention, is provided with a knurled or otherwise highly frictional surface 124 for providing a better grip on the surface of the tape of perforated scrap material to insure positive drive thereof.
If so desired, the distance between the axes of the rolls 98 and may be preset at a constant value such as to create a well defined clearance between the peripheral surfaces of the rolls providing a precise thickness sizing means for the tape 96.
As shown in particular details at FIG. 3, relative to the pair of downstream pinch rolls 102-104, each idler roll 100 or 104 is spring loaded towards its respective feed roll 98 or 102 by way of a pair of plungers 126, each disposed in a vertical bore 127 in the base plate 14 and biased by a compressed coil spring 128 such as to radially engage the ends of the shaft 108 or 112 on which is mounted the idler roll 100 or 104. It is obvious that the idler roller 100 or 104 may be coupled by gear, or other, means to'its respective feed roll 98 or 102. The shaft 108 or 112 is supported at both ends in a somewhat upwardly elongated bearing surface 130 formed in the pinch roll support brackets 132. The idler rolls 100 and 104 are preferably mounted on their respective support shafts 108 and 112 so as to be freely rotating therearound. The feed roll 98 or 100 being rigidly maintained along a constant horizontal axis of rotation by way of the shaft 106 or being journaled in the support brackets 132 by means of appropriate bearings such as needle bearings 134, the tape of stock material 96 is thus urged in driving engagement with the peripheral surface of the intermittently driven feed roll 98 or 102, and the arrangement of the feed pinch roll pairs thus further permits to accommodate various thicknesses of tape stock material.
The feed roll drive shaft 106 or 110 projects from the rear support flange 132 and is journaled in the bearing 136 of an additional support bracket 138. A commercially available one-way clutch mechanism 140 is mounted on the end of the shaft 106 or 110 projecting beyond the support bracket 138 and one end of a crank arm 142 is fastened to the periphery of the one-way clutch 140, as shown at FIGS. 2 and 4. The other end of the crank arm 142 is pivotally connected by means of a pivot pin 144 to an end of a connecting arm 146, such that when the connecting arm 146 is oscillated, both crank arms 142 are swung in unison. A vertically disposed roller 148 is mounted below the connecting arm I46 and is engaged in ahorizontal slot 150 formed by the bifurcated ends 152 of an arm 154 radially projecting from an angularly, or circularly, reciprocating drive member 156 mounted on the table 12. The radially reciprocating member 156 is part of the machine on the table 12 of which the apparatus of the invention is mounted and, when such machine is operated as a powder material compacting press, diverse elements such as the powder material dispenser, the compacting anvil, and the finished part ejecting or pick-up mechanism are normally mounted on the end of the arm 154, as explained in detail in the aforementioned patents.
It is evident from the preceding description that when the angularly reciprocating or oscillating member 156 is angularly reciprocated of one arcuate stroke around a vertical axis in timed relationship with the operation of the other drive means for the punch and die apparatus of the invention, such angular reciprocating being timed such as to be effected at the appropriate moment when the plate members 56 and 20 are no' longer clamping the tape of stock material 96 therebetween, the connecting arm 146 driven by the arcuately reciprocating arm 154 is caused to oscillate horizontally. The two one-way clutches 140, mounted respectively on the end of the shaft 106 and on the end of the shaft 110, are arranged such that when the connecting arm 146 is displaced leftwardly, FIGS. 2 and 4, and the,
upper ends of each the two crank arms 142 pivotally attached to the ends of the connecting arm 146 is also caused to be displaced leftwardly, the one-way clutches 140 drive the shafts I06 and 110, and consequently the feed rolls 98 and 102, counterclockwise of a predetermined are, thus feeding the tape of stock material 96 of a predetermined distance rightwardly, as seen in FIGS. 1, 2 and 4, such that a fresh portion of the tape of stock material 96 is caused to index with the punch and die assembly forming part of the apparatus of the present invention so as to punch further annular articles during subsequent clamping of that fresh portion of the tape of stock material 96 between the plate members 56 and 20. The return stroke of the arm 154 may be effected at any appropriate time during clamping of the tape of stock material between the plate members 56 and 20, and during such return stroke causing a rightward displacement of the connecting arm 136, the one-way clutches 140 are automatically disengaged, or free wheeling, such that no torque is applied to the feed roll drive shafts 106 and 110.
The sequential and timed advance, or linear translation, of the tape of stock material 96 between the plate members 56 and 20 is thus effected by a small increment at a time, of a distance each time which is sufficient only to clear the perforated portion of the tape of stock material from between the punch and die mecha nism. Such increment may be of the order of l/60,000 of an inch, or 1.5 mm, or less.
The increment of tape advance may be set such that the two parallel rows of holes 120 punched in the tape 96 during one punching cycle of the apparatus are con tiguous to each other or alternatively, set such that the rows are separated by a distance that permits one row of holes punched in the subsequent punching cycle to be situated in the tape material remaining between the two parallel rows punched at the first punching cycle. The advance increment can be set in one of several alternative manners. For example, the arms 142 (F IG. 3) may be made such as to have an adjustable length or, alternatively, the roller 148 (FIGS. 2 and 4) mounted below the connecting arm 146 may be mounted therebelow, adjustable along the longitudinal axis of the connecting arm 146 such that the vertical axis of the roller 148 may be disposed some distance away from the middle of the connecting arm 146. Alternatively, and preferably, the arm 154 is fastened to the angularly reciprocating drive member 156 so as to permit an initial angular relationship to be established between the arm 154 and the drive member 156 which, inturn, determines the longitudinal position of the connecting arm 146 and the angular position of the arms l42 prior to the beginning of one complete oscillation of the drive member 156.
It will be evident to those skilled in the art that the present invention may be subjected to many modifications and adaptations, without departing from the principle thereof. For example, although the invention has been described as a modular unit which can be substituted for the standard modular powder compacting tooling in a powder compacting press, it will be appreciated that the apparatus of the present invention may be built in any convenient form and operated by any convenient means well known in the art. As another example of modification of the invention, the upper plate member maybe separately operated by appropriate independent means, resulting in dispensing with the Belleville spring 92 (FIG. 1) and/or the coil springs 88. Also, one of the pairs of feed pinch rolls 98-l00 or l02-104 may be omitted, and they may be driven by any other convenient intermittent drive means such as, for example, a star-wheel drive mechanism, or the like. The feed pinch rolls could also be replaced by intermittently driven sprocket wheel means or by oscillating claw means with or without appropriate pin registration means, as is common in the motion picture industry for advancing photographic film in registration with a picture taking or projecting window, which will obviously require utilizing the stock material in the form of a preperforated tape with appropriate perforations disposed along one edge of the tape, or both edges, as is common practice in the photographic art.
It will be appreciated that terms and expressions such asfvertical, horizontal, upper," lower, etc. are
relative terms used only for the purpose of orientation of the diverse elements relative to the drawing in order to facilitate the description of the invention with reference to such drawing.
Although the apparatus of the invention has been described as capable of forming circularly annular arti- I cles, it will be appreciated that the principles of the invention are applicable to forming articles of any required peripheral shape, such as oval, triangular, square, rectangular or irregular shaped articles provided with one, two or more apertures of any peripheral shape whatsoever.
Having thus described the invention by way of a typical embodiment thereof, what is claimed as new is as follows:'
1. An apparatus for punching an annular part from a sheet of stock material, said apparatus comprising a first plate member, an aperture in said first plate member, a first punch disposed for reciprocation through said aperture, a longitudinal bore extending axially through said first punch, a second plate member, an aperture in said second plate member, a second punch disposed for reciprocation through said second plate member, said second punch having a projecting end portion adapted to fit the longitudinal bore of said first punch, and means for reciprocating said first and second punches and one of said plate members relative to the other in timed relationship for sequentially clamping said stock material between said plate members, reciprocating said first punch in engagement with a surface of said stock material, reciprocating said second punch to project the end portion thereof within the longitudinal bore of said first punch for punching a slug from said stock material, retracting said second punch and reciprocating said first punch to project through the aperture in said second plate for punching said annular part from said stock material.
2. The apparatus of claim 1 wherein said sheet of stock material is in the form of a continuous ribbon or tape and further comprising means for sequentially advancing said ribbon or tape to a position presenting a fresh portion of said stock material to the action of the punches for sequentially punching a plurality of said annular parts.
3. The apparatus ofclaim 1 further comprising means for extracting said slug from said bore in said first punch.
4. The apparatus of claim 3 wherein said means is an aspirator means.
5. The apparatus of claim 1 further comprising means for extracting said annular part form the aperture in said second plate.
6. The apparatus of claim 5 wherein said means comprises said first punch adapted to advance during retraction of said second punch to a position ejecting said annular part from said aperture in said second plate member.
7. The apparatus of claim 6 further comprising aspirator means for recovering said annular part.
8. The apparatus of claim 2 further comprising a plurality of pairs ofsaid first and second punches in at least one row disposed transversely to the axis of advance of said ribbon or tape, and means for reciprocating said first and said second punches in unison in timed relationship for simultaneously punching a plurality of said annular parts.
9. The apparatus of claim 8 further comprising single aspirator means for each cavity in said second plate for recovering said annular parts individually and a single receptacle connected to each aspirator means.
10. The apparatus of claim 1 wherein said first plate member is disposed below and said second plate member is disposed above said sheet of stock material.
11. The apparatus of claim 10 wherein said second plate member is mounted for reciprocation in unison with said second punch until the second plate member engages a surface of said stock material for clamping said stock material between said first and second plate members, and biasing means are disposed for maintaining said second plate member in engagement with said surface of the stock material during punching of said slug and of said annular part from said material.
12. The apparatus of claim 2 wherein said means for sequentially advancing said ribbon or tape of stock material comprises a pair of opposed pinch rolls, intermittent drive means for at least one of said rolls for pulling said ribbon or tape axially between said plate members when said plate members are reciprocated away from each other.
13. The apparatus of claim 12 wherein said roll driven by said intermittent drive means is peripherally provided with a roughened surface for deformably engaging a surface of said ribbon or tape after passage between said plate members.
14. The apparatus of claim 12 wherein said intermittent drive means comprises a crank arm mounted for radial motion at an end about an axis coincident with the axis of said roll, one-way drive means interconnecting said crank arm and said roll at said coincident axes, and means oscillating said crank arm through a predetermined arc.
15. The apparatus of claim 14 further comprising a second pair of opposed pinch rolls, said first mentioned pair and said second pair of pinch rolls being spatially disposed on opposite lateral sides of said plate members, a second crank arm mounted for radial motion at an end about an axis coincident with the axis of one of said rolls of said second pair, one-way drive means interconnecting said crank arm and said roll at said coincident axes, connecting arm means pivotally interconnecting said first and second crank arms for oscillation through said predetermined arc in unison, and driving means for oscillating said connecting arm means.