US3507009A - Rotary pressing machine for manufacture of toroidal cores and analogous discs - Google Patents

Description

Apnl 21, 1970 E. H. COMLY 3,507,09

Y ROTARY PRESSING MACHINE FOR MANUFACTURE OF TOROIDAL CORES AND ANALOGOUS DISCS Filed Aug. 18, 1967 3 Sheets -Sheet 1 FIG. I INVENTOR ELWOOD HOWARD COMLY ATTORNEY April 21. 1970 E. H. COMLY 3,507,009

ROTARY PRESSING MACHINE FOR MANUFACTURE OF TOROIDAL CORES AND ANALOGOUS DISCS Filed Aug..l8, 1967 3 Sheets-Sheet 2 FIG. 2

INVENTOR ELWOOD HOWARD COMLY BY WW ATTORNEY 'A ril21, 1910 E.H.0MLY v3,507,009

ROTARY PRESSING MACHINE FOR MANUFACTURE OF TOROIDAL CORES AND ANALOGOUS DISCS v Filed Aug. 18, 1.967 3 Sheets-Sheet 5 FIG. 3

FIG. 4

INVENTOR' ELWOOD HOWARD COMLY BY M I ATTORNEY United States Patent ROTARY PRESSING MACHINE FOR MANUFAC- TURlg 0F TOROIDAL 'CORES AND ANALOGOUS DISC Elwood H. Comly, 2065 Bennett Road, Philadelphia, Pa. 19116 Filed Aug. 18, 1967, Ser. No. 661,658 Int. Cl. B29c 3/02 US. C]. 18-20 12 Claims ABSTRACT OF THE DISCLOSURE A compacting apparatus consisting of a base, a center post extending upwardly from the base, a plurality of dies adapted to rotate about the post, an upper and lower punch mounted coaxially to each die and adapted to rotate in conjunction therewith and means for causing the punches to enter the die. The means consists of a rocker arm pivotally mounted adjacent each punch in constant contact therewith. In operation, as the dies, punches and rocker arms rotate about the center post, the rocker arms are caused to contact a cam means which pivots the rocker arms causing them to move the punches into the die. The principle of the apparatus is especially useful in the manufacture of toroidal cores and analogous discs wherein the rotary pressing action increases production capacity.

This invention relates to an apparatus for accurately compacting comminuted materials to very precise tolerances, and more particularly, to an improved apparatus for making shaped semiconductors and ceramic compacts for use as electronic products, the semiconductors and compacts being automatically manufactured under very precise dimensions from finely comminuted solid materials.

One type of material which is used extensively in semiconductors and high frequency electronic technology is known as ferrites. Ferrites are comprised of mixed solid metallic oxides of high resistivity which are compacted in finely divided form under pressure and are sintered. During the sintering process carried out at high temperatures, the compact mixture in the molded form crystallizes into a crystalline structure like that of a mineral spinel. The resulting ferrite has a hard, black and nonporous ceramic appearance; its various electronic applications include use as a core material in flyback transformers and deflecting yokes, and as magnetic memories and magnetic switches at frequencies up to fifteen megacycles. More particularly, these ferrite cores are polycrystalline ferri-magnetic bodies of sintered crystallites which are characterized by either a cubic or hexagonal crystal structure.

One widely used method of preparing a ferrite core comprises intimately mixing the metal oxide participating in ferrite formation with one or more other metal oxides such as zinc oxide and manganese oxide. A binder-lubricant is added to the mixture and then the mixture is comminuted to provide a uniform distribution. The binderlubricant addition may be any one of a number of commercially available products, such as Wax, starch and metal stearate. Subsequently, the comminuted mixture, which is referred to herein as the green ferrite composition, is pelletized, dried and then shaped or molded by pressing to form the green ferrite body. The green ferrite body is small in size and is molded to very precise minute tolerances.

The green ferrite body is then subjected to a low temperature (about 400 to 500 F.) heat treatment in air, which is referred to as a dewaxing treatment, to remove the binder-lubricant and other volatile matter. Follow- 3,507,009 Patented Apr. 21, 1970 ice ing the dewaxing treatment, the body is then subjected to a high temperature (about 1800 to 2600 F.) heat treatment, referred to as sintering, in order to react the metal oxides below their melting points and to produce the ferrite crystallites, to thereby cement and sinter the crystallites to each other to form a unitary body or core to which are imparted the desired ferrimagnetic properties which make the core unique as an electronic unit.

Ordinarily, the binder-lubricant is comprised of materials which volatilize over different temperature ranges during dewaxing to form gaseous products which burn upon contact with the air. Where the dewaxing is carried out in air, this burning raises the temperature of the body to one or more temperature peaks, referred to as exothermic temperature peaks. Each of these temperature rises and falls is generally sharp and results from the volatilization and burning of a particular constituent of the binder-lubricant. Strains develop in the body as a result of the heat distribution due to the non-uniform thickness dimension of the body. In many cases, the green ferrite body cracks or shatters as a result of the strain.

In the utilization of the molded semiconductor mixture for the manufacture of-an annular magnetic core suitable for use as a storage element in a magnetic memory, the magnetic core must be shaped in very thin sections and must be molded in highly precise, exacting dimensions in order to supply the desired electrical and magnetic parameters. For example, an annular core having an outer diameter not exceeding 0.6 millimeter and an inner diameter which is at least half that of the outer diameter and which is constituted of a fired reaction product of lithium oxide, nickel oxide and ferric oxide in the proportion of about 14 to 15 mol percent of H 0, about 5 to 7 mol percent of NiO and about 78 to 81 mol percent of Fe O has a switching time not exceeding 0.25 ,4 seconds and a disturbance ratio of 0.61. These are critical limitations in performance for switching and memory read-in and read-out.

In order to produce small, very thin semiconductors from comminuted material, the compacting apparatus must be extremely accurate and capable of holding dimensions and tolerances to less than one-tenth of a mil. In addition to being accurate in the dimensional tolerances of the semiconductor, the apparatus must be capable of producing the semiconductors on a mass production basis at relatively low cost. This is particularly important since it is estimated that, in the United States alone, over 25 million cores are used per year. Core arrays provide such fast, reliable random access memories that practically every computer in use today utilizes them.

However, it is a known fact that as machines become more automated and run at higher speeds, in order to produce a product on a mass production basis, sacifices must be made in the dimensional accuracy of the product and this destroys the quality of the resultant product. In the production of semiconductors and particularly magnetic memories, any deviation from the predetermined dimensions causes a profound change in the operating characteristics of the device. In memory cores fabricated in an annular configuration, three dimensions are very critical from the standpoint of producing the desired characteristics. These critical dimensions are the outside diameter, the internal diameter and, most important, the thickness.

Because of the advantages of microminiaturized cores, namely that the smaller core, the less driving current it requires, the faster it switches for a given current and the tighter it can be packed to minimize delays along windings, the trend in the computer industries has been towards microminiaturization. As the art has progressed over the years, standard core sizes have graduall? decreased from 80 mils outside diameter and 50 mils inside diameter, known in the trade as an 80/50 core, to 50/30, 30/ 18, 20/12 and, recently, even to 12/7. Typical arrays of 20/ 12 cores contain 16,384 of them in a square plane that measures only 6.4 inches on aside. Since the outside diameter, internal diameter and thickness must all be proportional, the thickness of the annular core is usually just a few mils.

Actually, most magnetic cores have a thickness range of .5 .mil to 5.0 mils with the average being between 2 and 3 mils. Obviously, if the core is to have a thickness of 3 mils and the compacting apparatus is only accurate to 2 mils, then there is a possibility and probability of a 66% error.

Presently existing machines such as shown in Stokes US. Patent No. 1,289,570 which are capable of producing cored semiconductor devices normally consist of a die, a lower core rod and punch combination and an upper punch. The dies and punches are mounted on a rotary turntable and are rotated under a cam which causes the punches to enter the die and compress the comminuted materials within the die.

The punches and the dies are expensive to manufacture because they must be machined to exacting tolerances in order to effectively compress the comminuted materials within the die without causing a flash. When the punches are rotated into contact with the cam surface, the action of the cam upon the head portion of the punch causes the punch head portion to wear. This wear is increased in accordance with an increase in the speed of rotation and the amount of pressure applied to the punch by the cam. In the Stokes patent, the actuating :am rotates in one direction and the punches in an opposite direction. This contra-rotation creates a sliding friction between the contracting parts which causes a high degree of wear of both the cam and the punch heads. Additionally, the head portion of the punches slides along a fixed stationary surface and continuously wears as the rotary head containing the punches rotates. Naturally, any Wear in the compressing actuating means will cause a change in the dimensions of the product being compressed. Additionally, it has been determined that, in ejecting a thin, compressed, green comminuted product from its forming die, the distance of ejection should be no greater than the thickness of the product. Semiconductor products, the thickness ranges of which are between .5 and 5.0 mils, are naturally very fragile and diflicult to work with and handle since the slightest :ype of shock or unequal pressure will cause them to break when they are in a green condition. When the ejection distance that the semiconductor must travel is greater than the thickness of the semiconductor, stresses are set up in the semiconductor and they tend to crack and break.

In order to alleviate the aforementioned wear and breakage problems, a compacting apparatus has been invented by the applicant which provides an improved :ompacting, actuating and ejection means and generally provides an apparatus for making semiconductors to extremely close tolerances from comminuted materials in an automatic manner without the wear and tolerance problems normally associated with such apparatus.

The improved compacting apparatus consists of a base having a center post extending vertically therefrom. A die table having a plurality of dies disposed in a circular pattern and separated by a constant arc is adapted to rotate about the center post. A means is provided to rotate the dies about the center post at a desired speed. An upper punch is mounted coaxial to and above each :lie and is adapted to rotate with the die. A lower punch is mounted below and partially within the die and also is adapted to rotate with the die. A rocker means consisting of an upper rocker means and associated rollers and a lower rocker means and associated rollers is pivotally mounted so that the upper rocker means is in constant wear-free contact with the upper punch and the lower rocker means in in constant wear-free contact with the lower punch. A cam means consisting of an upper cam means and an adjustable lower cam means is mounted adjacent the rocker means and is adapted to pivot the rocker means to cause the contacted punches to be moved into the dies. The lower cam means consists of a plurality of cam slidably mounted in the base coplanar to one of the associated rollers on the lower rocker means. The cams are separated by an are equal to the arc separating the dies. A means is provided for varying the radial distance of the cam means from the center post. By varying the radial distance of the cams from the center post, the depth of penetration of the punch into the die can be controlled.

An object of the present invention is to provide an improved apparatus for making semiconductors from comminuted materials.

Another object is to provide an improved method of making semiconductors from comminuted materials.

Another object is to provide an improved compacting punch actuation means.

Another object is to provide an improved ejection means for the compacted, green product.

Another object is to provide a substantially wear-free method and apparatus for actuating the compacting punches.

Another object is to provide an improved means for adjusting the forming pressure of the compacting punches.

Further objects and advantages of the present invention will be brought out in the following specification wherein, for the purposes of completeness of disclosure, 2. preferred embodiment has been described in detail without intending to limit the scope of the invention as set forth in the appended claims.

The attached drawings illustrate the preferred embodiment of the invention in which:

FIGURE 1 is a perspective view of the compacting apparatus;

FIGURE 2 is a cut-away view of a substantially symmetrical portion of the apparatus of FIGURE 1, with the punches in their compacting position;

FIGURE 3 is an enlarged vertical sectional view of an upper punch and rocker means of the apparatus just prior to compacting;

FIGURE 4 is a top perspective view of the lower rocker means and cam means; and

FIGURE 5 is a side cut-away view of the filling mechanism and its relationship to a die.

Referring now to the drawings wherein like reference numerals designate like or corresponding parts throughout the several views, there is shown in FIGURES l, 2 and 3 compacting apparatus 10 having a base 50 and a main center post 11 extending vertically from the center of the base 50. An annular lower head section 12 and an annular upper head section 13 rotate on bearings 14 about the center post 11. The lower and upper head sections 12 and 13 are rotated about the center post 11 by a worm gear arrangement 15.

The annular upper and lower head sections 13 and 12 have a flange extending outwardly around the upper periphery thereof. In effect, the configuration of the lower and upper head sections is similar to that of a T wherein the outwardly extending flange forming the arms of the T is positioned along the top of the leg of the T which encircles the center post 11.

The lower and upper head sections 12 and 13 are rotated through the worm gear arrangement 15 by a suitable rotation means, such as a variable speed motor and clutch (not shown). The variable speed motor and clutch can be any one of many known to those skilled in the art.

An example of a suitable motor is a NSH-SSRH, as sold by Minarik Electric Company of Los Angeles, Calif. The NSH-55RH is a DC. Bodine gear motor. A suitable clutch for use in the present invention is sold by the Rock ford Clutch Division of the Borg-Warner Corporation of Rockford, 111., under the name of .No. 1 Single Dry Pullmore Clutch. While the applicant has, for the sake of illustration and completeness of disclosure, named a specific operative motor and clutch, it will be obvious to those skilled in the art that numerous other motors and clutches can be utilized successfully.

The lower and upper head sections 12 and 13 are drivably connected to each other by a plurality of threaded pins 16 which additionally serve to securely retain a die table 17 in alignment between the lower and upper head sections. The lower surface of the die table 17 lies in abutting overlapping relationship to the upper surface of the flange of the lower head section 12.

The die table 17 has an annular configuration and is secured between the lower head section 12 and the upper head section 13 so that when the head sections are rotated about the center post 11 by the rotation means, the die table 17 rotates with the head sections. Disposed intermediate the inner and outer diameters of the die table 17 in a circular pattern separated by a constant are are a plurality of apertures 18. The apertures 18 are disposed through the die table 17 in a direction parallel to the center post 11 and at a fixed common radial distance from the center line 19 of the post 11.

A die 20 is secured within the aperture 18 by a set screw 21. The die 20 is annular and its inner diameter is the desired outer diameter of the product to be formed therein. The die 20 can easily be removed and replaced with dies having different configurations and internal diameters in order to form various types and shapes of products.

Extending through the flanges of the upper and lower head sections 13 and 12 in coaxial alignment with the dies 20 are guideways 22. Disposed in the guideway 22 in the flange of the upper head section 13 is an upper punch 23. The punch 23 has an external diameter sized to slide smoothly within the guideway 22 and an upper flanged head portion 24. A spring 25 is disposed about the punch 23 between the upper surface of the flange of the upper head section 13 and the lower surface of the flanged head portion 24. The spring 25 urges the punch 23 upwardly away from the die table 17. The punch 23 has an opening 26 in its lower end; the opening 26 is concentric to the punch 23 and is adapted to receive therein a forming member 27. The forming member 27 has an outer diameter sufiicient to enter the die 20. A set screw 28, extending through the wall of the punch 23 into the opening 26, retains the forming member 27 in position during operation of the compacting apparatus 10. The forming member 27 can easily be removed and replaced with differently configured members to match a change in dies or configuration of the compacted product, by manipulation of the set screw 28.

Extending through the guideway 22 in the lower head section 12 is a lower punch 29. The lower punch 29 is similar to the lower punch as shown and described in Baily US. Patent No. 2,068,619. Depending upon the type and size of the core rods used in the lower punch 29, the'forming member 27 of the upper punch 23 will have complementary openings to receive the core rods when it is desired to produce a product having core holes therethrough. If a cored end product is not desired, then a lower punch constructed in accordance with the upper punch 23 without the openings will be utilized. As illustrated in the drawings, a spring 30 is disposed between the lower surface of the flange of the lower head section 12 and the upper surface of a flanged head portion 31 of the lower punch 29 serves to bias the lower punch 29 away from the die table 17 As illustrated best in FIGURE 3, there is secured to the upper surface of the flange of the upper head section 13 intermediate the upper punch 23 and the center post 11 an upper rocker arm ring 32. The ring 32 is disposed concentrically about the center post 11 and has an upwardly extending rocker arm holder 33 adjacent each 6 punch 23. Secured to each holder 33 is a rocker arm means consisting of a rocker arm 34, a punch roller 36 and a cam roller 37.

The rocker arm 34 has a bifurcated end, the branches of which are separated by a sufficient distance to encompass the holder 33 therebetween. A pivot pin 35 extends through the bifurcated end of the rocker arm 34 and the holder 33 in order to retain the rocker arm 34 in pivotal relationship to the holder 33. The upper rocker arm punch roller 36 is rotatably disposed between the branches of the bifurcated end of the rocker arm 34 in contact with the head portion 24 of the upper punch 23. Since the upper rocker arm holder 33 is secured to the ring 32 and therefore to the upper head section 13, the rocker arm 34 rotates with the upper punch 23 and the roller 36 remains in constant contact with the upper punch head portion 24, this continuous contact being assisted by the action of the spring 25 urging the punch 23 upwardly towards the rocker means, the roller encompassing portion of which overlays the punch 23. The cam roller 37 is rotatably secured to the upper end of the upper rocker arm 34 and is disposed in a substantially horizontal plane. By applying a force to the cam roller 37 in a direction outward from the center line 19, the rocker arm 34 will pivot about the bolt 35, causing the punch roller 36 to move downwardly against the head portion 24 of the punch 23. The downward movement of the punch 23 is partially resisted by the spring 25.

A cam means 39 having an actuating portion 38 is secured to the center post 11. The cam means 39 has an annular configuration and circumscribes the center post 11 so that the lower surface of the cam 38 abuts a shoulder 40 which is located on the center post 11 adjacent the actuating roller 37. A nut 41 holds the cam 38 in a fixed position on the center post 11. The cam 38 is secured to the center post 11 so that the actuating portion 39 is coplanar with the cam roller 37 and so that, when the upper head section 13 is rotated causing the upper rocker arm 34 to rotate with it, the roller 37 rides along the periphery of the cam 38. When the roller 37 passes over the cam actuating portion 39, the upper end of the rocker arm 34 is forced outwardly, causing the entire rocker arm 34 to pivot about the bolt 35. As mentioned hereinbefore, the outward pivoted movement of the rocker arm 34 causes the punch roller 36 to force the upper punch 23 downwardly, compressing the spring 25 and allowing the forming member 27 to enter the die 20. By adjusting the radial distance of the actuating portion 39 of the cam 38 from the center line 19, the forming member 27 can be caused to enter the die 20 to any depth desired. Additionally, by allowing the roller 37 to ride along the periphery of the cam 38 so that the spring 25 causes the head portion 24 of the punch 23 to remain in contact with the punch roller 36, the head portion 24 does not become worn due to sliding, rubbing or rolling contact with the punch roller 36. The cam 38 provides a limit to the upward travel of the punch 23 due to the urging of the spring 25. The outer diameter of the cam 38 should be sized so that, when the roller 37 is not in contact with the actuating portion 39, the forming member 27 of the punch 23 is disposed a suflicient distance above the die 20 to allow the die 20 to be filled with the annular configuration and circumscribes the center post 11 so that the lower surface of the cam 39 abuts a shoulder 40 which is located on the center post 11 adjacent the actuating roller 37. A nut 41 holds the cam 39 in a fixed position on the center post 11. The cam 39 is secured to the center post 11 so that the actuating portion 38 is coplanar with the cam roller 37 and so that, when the upper head section 13 is rotated causing the upper rocker arm 34 to rotate with it, the roller 37 rides along the periphery of the cam 39. When the roller 37 passes over the cam actuating portion 38, the upper end of the rocker arm 34 is forced outwardly, causing the entire rocker arm 34 to pivot about the bolt 35. As mentioned hereinbefore, the outward pivoted movement of the rocker arm 34 causes the punch roller 36 to force the upper punch 23 downwardly, compressing the spring 25 and allowing the forming member 27 to enter the die 20. By adjusting the radial distance of the actuating portion 38 of the cam 39 from the center line 19, the forming member 27 can be caused to enter the die to any depth desired. Additionally, by allowing the roller 37 to ride along the periphery of the cam 39 so that the spring causes the head portion 24 of the punch 23 to remain in contact with the punch roller 36, the head portion 24 does not become worn due to sliding, rubbing or rolling con tact with the punch roller 36. The cam 39 provides a limit to the upward travel of the punch 23 due to the urging of the spring 25. The outer diameter of the cam 39 should be sized so that, when the roller 37 is not in contact with the actuating portion 38, the forming member 27 of the punch 23 is disposed a sufiicient distance above the die 20 to allow the die 20 to be filled with the material to be compressed.

Referring now to FIGURE 4, there is shown an annular lower rocker arm ring 42, the ring 42 being secured to the lower surface of the flange portion of the lower head section 12 at a point outwardly of the lower punch 29. The ring 42 is disposed concentrically about the center post 11 and has a cut-away portion adjacent each punch 29. Disposed within each cut-away portion is a lower rocker means 43. The lower rocker means 43 consists of a rocker arm 44, a punch roller 46, a cam roller 47 and a dwell roller 48. The lower rocker arm 44 is pivotally secured to the rocker arm ring 42 by a pivot pin 45 which extends through the rocker arm ring 42 and the upper end of the rocker arm 44. Extending inwardly of the pivoted end of the rocker arm 44 is a bifurcated portion, the branches of the bifurcated portion extending vertically and inwardly beneath the head portion 31 of the punch 29. Rotatably disposed between the branches of the bifurcated end of the rocker arm 44 in contact with the head portion 31 of the punch 29 is the lower punch roller 46. Since the lower rocker arm ring 42 is secured to the lower head section 12, the rocker means 43 rotates with the lower punch 29 and the roller 46 remains in constant contact with the head portion 31 of the punch, this continuous contact being assisted by the action of the spring urging the punch 29 downwardly towards the roller 46. Extending outwardly from the pivoted end of the rocker arm 44 is another bifurcated portion, the branches of which extend horizontally outwardly relative to the pivoted end of the rocker arm 44. Rotatably disposed between the horizontal branches of the rocker arm 44 is a cam roller 47 which is disposed in a substantially horizontal plane. A dwell roller 48 is also rotatably mounted between the horizontal branches of the rocker arm 44, the dwell roller being mounted in overlying parallel juxtaposition to and coaxial with the cam roller 47. A pin 49 retains the cam roller 47 and the dwell roller 48 in their respective positions between the horizontal branches of the rocker arm 44 while enabling the rollers to rotate in a substantially horizontal plane.

Adjustably mounted on the base 50 in a horizontal plane is a cam means consisting of a fill cam 51, a pressure cam 52 and an ejection cam 53. The fill, pressure and ejection cams are slidably mounted in cut out portions in the upper surface of the base 50 coplanar to the cam roller 47 so that the cam roller 47 when rotating with the lower head section 12 will come into rolling contact with the cams. The cams are positioned in the base 50 in the proper order so that when the lower head section 12 is rotating, the cam roller 47 will first contact the fill cam 51 and then the pressure cam 52 and lastly the ejection cam 53'. Secured to the upper surface of the base 50 is an annular dwell ring 54. The dwell ring 54 overlays the base 50 and the cams 51, 52 and 53 so that the cams are sandwiched between the base 50 on their sides and lower surface and the dwell ring 54 on their upper surface.

The fill, pressure and ejection cams are separated by an arc equal to the arc separating the dies 20- so that only one cam roller 47 is in contact with an individual cam at any one time. Therefore a maximum of three cam rollers 47 may be in engagement with the cams at any one time; one of the rollers 47 would be in contact with the fill cam 51, one with the pressure cam 52 and one with the ejection cam 53. All of the remaining cam rollers 47 are held in spaced relationship from the internal wall of the base 50 by the dwell rollers 48 which are in con tact with the internal diameter of the dwell ring 54. The dwell rollers 48 have a greater radius than the cam rollers 47 and when the cam roller 47 is not in contact with a cam the dwell roller 48 comes into contact with the internal diameter of the dwell ring 54. Since the dwell ring 54 has a smaller internal diameter than the base 50, the dwell roller 48 will contact the dwell ring 54 and the cam roller 47 will be held in spaced relationship to the internal diameter of the base 50. The dwell roller 48 is held in rotating contact with the inner periphery of the dwell ring 54 by the action of the spring 30, which urges the lower punch 29 against the rocker arm 44 causing the rocker arm to pivot about the pivot pin 45. The cams 51, 52 and 53 are provided with means to change their distance from the center line 19 and therefore can be adjusted outwardly or inwardly. It is important to the correct operation of the compacting apparatus 10 that the actuating portion 38 of the cam 39 be located directly above the pressure cam 52. This is necessary so that the upper punch 23 enters the die 20 at the same time that the cam roller 47 is in contact with the pressure cam 52 in order to compress the material therein. By varying the radial distance of the pressure cam 52 from the center line 19, the amount of pressure exerted on the material being compressed can be controlled.

When the cam roller 47 contacts the cam surface of the pressure cam 52 the rocker means 43 is pivoted inwardly about the pivot pin 45. The inward pivoting of the rocker arm 44 causes the punch roller 46 to move upwardly against the head portion 31 of the lower punch 29. The amount of upward movement of the punch 29 determines the depth of penetration of the punch 29 into the die. 20. Therefore, by moving the pressure cam 52 inwardly towards the center line 19, the punch roller 46 is forced upwardly a greater distance, causing the punch 29 to move into the die 20 a greater distance against the pressure of the spring 30. The punch 29 is adjusted so that at all times the punch is within the die 20 to a limited extent. In other words, even when the dwell roller 48 is in contact with the dwell ring 54, the rocker arm 44 and the punch roller 46 are positioned so that the downward movement of the punch 29 due to the action of the spring 30 is insufficient to allow the punch 29 to travel below the lower surface of the die 20' due to the abutment of the dwell roller 48 against the dwell ring 54.

The depth of penetration of the punch 29 into the die 20 during the fill cycle is controlled by the fill cam 51. By varying the radial distance of the fill cam 51 from the center line 19, the amount of material that can enter the die 20 is controlled. The ejection cam 53 is positioned at a sufiicient radial distance from the center line 19 to cause the end of the punch 29 to enter the die 20 to a point flush with the upper surface of the die. By causing the punch 29 to pass completely through the die 20, the compacted product will be forced out of the die onto the surface of the die table 17, where it can be removed.

As illustrated in FIGURE 5, a fill spout 55 is mounted in a fixed position so that a discharge orifice 56 is above and adjacent the dies 20. By placing the discharge orifice 56 at the same fixed radial distance from the center line 19 as the dies 20, the material which is discharged through the orifice 56 will fall into the die 20 as the die passes under the orifice 56. The spout 55 is connected to a hopper (not shown) which can be agitated by a shaker in order to cause the powdered material to flow down from the hopper through the spout 55 and out the orifice 56 9 into the die 20. As the die 20 passes out from under the spout 55 a wiper blade 57 wipes away the excess material which has not entered the die 20, but has fallen on top of the die table 17. The excess material is then returned to the hopper. A plurality of hoppers and spouts 55 can be utilized in order to insure that the die 20 is completely filled. The amount of material that will be allowed to enter the die 20 is controlled by the degree of penetration into the die 20 by the punch 29 as regulated by the fill cam 51 in a manner hereinbefore described.

In order to accurately describe the operation of the compacting apparatus 10, the path of rotation and effect of operation of an individual upper rocker means and an individual lower rocker means will be described. However, it should be remembered that a plurality of upper and lower rocker means are simultaneously rotating about the center post during actual operation.

In operation, the rotation means is energized causing the worm gear arrangement to simultaneously rotate the lower and upper head sections 12 and 13 and die table 17 at the same rate about the center post 11.

During the rotation of the head sections, the upper rocker arm cam roller 37 rolls along the periphery of the cam 39 and the lower rocker arm dwell roller 48 rolls along the inner periphery of the dwell ring 54. As mentioned hereinbefore, the spring 30 holds the dwell roller 48 in contact with the inner periphery of the dwell ring 54 and since the radius of the dwell roller 48 is greater than that of the cam roller 47, the cam roller is caused to rotate with the head section free from engagement with any surfaces. When the head sections have rotated to the point where the fill cam 51 is positioned, the cam roller 47 engages the surface of the fill cam and is forced inwardly causing the lower rocker arm 44 to pivot about the pivot pin 45. The pivotal movement of the rocker arm 44 causes the punch roller 46 to move upwardly against the head portion 31 of the punch 29. The action of the punch roller 46 causes the punch 29 to penetrate the die to a predetermined depth, thereby serving as a lower level for the material therein, By varying the radial distance of the fill cam 51 from the center line 19, the amount of material that can be deposited in the die 20 by the fill spout 55 is regulated. Since material is entering the die 20 before the cam roller 47 engages the fill cam 51, the subsequent upward movement of the punch 29 within the die 20 forces some of the material out of the die above the level of the die table 17. A wiper blade 57 removes this excess material so that only the correct predetermined amount of material is left in.

the die 20. During the fill operation, the upper cam roller 37 rolls along the periphery of the cam means 39. After the fill operation the dwell roller 48 again engages the inner periphery of the dwell ring 54 until the cam roller 47 engages the actuating surface of the pressure cam 52. Simultaneously with the cam roller 47 engaging the cam 52, the upper cam roller 37 engages the actuating portion 38 of the cam 39. The simultaneous action of the cam means on the rocker means causes the upper and lower rocker arms 34 and 44 to pivot about their respective pivot pins 35 and 45. The pivotal movement of the rocker means causes the punch rollers 36 and 46 to push the upper and lower punches deeply into the die 20, thereby compacting the material contained therein.

Since the compacting pressure is usually quite great and can possibly exceed the strength of the punches, the means for varying the radial distance of the lower pressure cam 52 is spring loaded. By spring loading the pressure cam 52 to a point less than the strength of the punches, when the punch pressure exceeds the spring pressure the pressure cam 52 will move outwardly against the biasing force of the spring, thereby reducing the pressure on the punches and providing an overload safety factor. In effect, the spring biasing of the pressure cam 52 serves as a compacting pressure adjustment means by varying the radial distance of the cam from the center line 19 and as an overload safety device.

After the compacting operation, the upper actuating roller 37 rolls off the actuating portion 38 of the cam means and returns to its original or non-compacting position and the upper punch 23 exits from the die 20 and returns to its non-compacting position above the die table 17. The dwell roller 48 contacts the dwell ring 54 and the cam roller 47 contacts the ejection cam 53. When the cam roller 47 contacts the actuating surface of the ejection cam 53, the rocker means 43 is pivoted about the pivot pin 45. The pivotal movement of the rocker arm 44 causes the lower punch roller 46 to move upwardly against the head portion 31 of the lower punch 29. The movement of the punch roller 46 causes the punch 29 to penetrate the die 20 to a point at least flush with the upper surface of the die table 17. The upward movement of the punch 29 through the die 20 causes the compacted product produced by the compacting punch operation to be pushed out of the die 20 onto the die table 17, where the wiper blade 57 directs it to an unloading chute.

From the foregoing, it will be seen that there has been devised an extremely simple compacting apparatus for comminuted products, consisting of a center post and a plurality of dies rotating about the center post. A pair of punches are positioned coaxially to each die and a rocker means is pivotally mounted in substantially Wearfree engagement with the punches. The rocker means is adapted to pivot and move the punches into the dies when contacted by a cam means. The punches and rocker means of the compacting apparatus are substantially free from wear because of the absence of rubbing or sliding contact. Since the rocker means is in constant contact with the head portions of the punches without substantial relative movement between them, there is no appreciable wear of either of the parts. Additionally, since the dwell roller causes the lower cam roller to rotate in suspension without coming in contact with any surfaces except the actuating surface of the cam means, the cam roller has no appreciable wear, even after extensive use of the apparatus.

Since certain changes may be made in the above apparatus, and different embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description (or shown in the accompanying drawings) shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim:

1. In an improved compacting apparatus having a center post, a plurality of dies rotating about said center post and a pair of punches in coaxial alignment with each die, the improvement comprising:

a rocker means pivotally mounted including a roller element in constant free contact rolling with each of said punches; and

a cam means adapted to pivot said rocker means whereby said punches are moved into said die. E

2. A compacting apparatus in accordance with claim 1 wherein said rocker means comprises:

a rocker arm adapted to rotate with said dies and pivotally secured adjacent thereto;

said roller element including a punch roller rotatably secured to said rocker arm in constant contact with said punch; and

said cam means including a cam roller rotatably secured to said rocker arm and adapted to contact said cam means whereby said cam means pivots said rocker arm causing said punch roller to move said punch into said die.

3. An improved compacting apparatus comprising:

a base;

a center post extending vertically from said base;

a plurality of dies adapted to rotate about said center post at a fixed radial distance therefrom;

a means for rotating said dies about said center post;

an upper punch mounted above and coaxial to said die and adapted to rotate in conjunction therewith;

a lower punch mounted below and partially within said die and adapted to rotate in conjunction there- 8. A compacting apparatus in accordance with claim 7 wherein said adjustable lower cam means comprises:

a fill cam slidably mounted on said base coplanar to said cam roller;

means for varying the radial distance of said fill cam from said center post;

a pressure cam slidably mounted on said base coplanar to said cam roller;

means for varying the radial distance of said pressure cam from said center post;

with; an ejection cam slidably mounted on said base coan upper rocker means pivotally mounted including a planar to said cam roller; and

roller element in constant free rolling contact with means for varying the radial distance of said ejection said upper punch; cam from said center post, said fill pressure and a lower rocker means pivotally mounted in constant 15 ejection cams being separated by an are equal to the substantially wear Lfree contact with said lower punch;

a fixed upper cam means adapted to pivot said upper rocker means whereby said upper punch is urged into said die; and

an adjustable lower cam means adapted to pivot said lower rocker means whereby said lower punch is urged into said die for adjustably varying distances.

4. -A compacting apparatus in accordance with claim 3 wherein said upper rocekr means comprises:

a rocker arm pivotally mounted adjacent said upper punch;

said roller element including a punch roller rotatably secured to one end of said rocker arm in constant free rolling contact with said upper punch; and

a cam roller rotatably secured to an opposite end of said rocker arm in constant rotatable contact with said fixed upper cam.

5. A compacting apparatus in accordance with claim are separating said dies. 9. A compacting apparatus in accordance with claim 7 wherein said lower punch is spring biased away from said die whereby the spring pressure holds said dwell roller in contact with the inner periphery of said dwell ring.

10. A compacting apparatus in accordance with claim 8 wherein said means for varying the radial distance of said pressure cam from said center post is spring loaded whereby said spring provides an overloading safety factor.

11. A compacting apparatus in accordance with claim 3 wherein said lower cam means and said upper cam means are mounted in a common vertical plane.

12. A method of compacting a comminuted product comprising the steps of:

rotating a plurality of dies about a center post; rotating an upper punch disposed above and coaxial to said die in conjunction therewith;

4 wherein said upper punch is spring biased away from Totaling a lower Punch disposed Partially Within Said said die whereby the spring pressure holds said cam die in conjunction therewith; roller in constant contact with said fixed upper cam. rotating an pp rocker arm With Said P1 Punch and 6. A compacting apparatus in accordance with claim inconstallt rolling Contact therewith; 3 further comprising a dwell ring mounted on said base rotating 3 lower rocker arm With Said lower Punch and symmetrically about said center post in overlapping in constant rolling Contact therewith; juxtaposition to said lower cam means. pivoting Said pp rocker arm downwardly thereby 7. A compacting apparatus in accordance with claim causing Said pp punch to I110"e into Said and 6 wherein said lower rocker means comprises: pivoting Said lower rocker arm p y thereby calls" a rocker arm pivotally mounted adjacent said lower ing Said lower Punch to move into d punch; a punch roller rotatably secured to one end of said References C'ted rocker arm in constant wear free rolling contact with UNITED STATES PATENTS sald lower p 1,267,632 5/1918 Claussen. a cam roller rotatably secured to an opposite end of 1,711,978 5/1929 Wanders said rocker arm and adapted to contact said adjust- 2,058,880 10/1936 Hunt, able lower cam means, and 2,354,029 7/1944 Kingston 25-65 X a dwell roller rotatably secured to said rocker arm in 2,224 653 12 19 Lane et a].

parallel, overlapping juxtaposition to said cam roller, 2,651,809 '9/ 1953 Merchur t 1, said dwell roller having a radius greater than said 3,112,521 12 19 3 Ward XR cam roller and adapted to roll along the inner periphery of said dwell ring when said cam roller is WILBUR MCBAY, P m ry Xaminer not in contact with said lower cam means, said dwell US. Cl. X.R.

roller when in contact with said dwell ring causes said cam roller to rotate in contact free suspension. 25-65; 107-17

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