US3422658A - High velocity forming machine - Google Patents

Description

Jan. 21, 1969 A. MICHELSON HIGH VELOCITY FORMING MACHINE Sheet of 4 Filed Feb. 10, 1967 INVENTOR. ANATOL MICHELSON Jan. 21, 1969 A. MICHELSON HIGH VELOCITY FORMING MACHINE Filed Feb. 10, 1967 INVENTOR. ANATOL MICHELSON BY W W FIGS ATTORNEYS.

Jan. 21, 1969 A. MICHELSON HIGH VELOCITY FORMING MACHINE Sheet 3 of 4 Filed Feb. 10, 1967 INVENTOR. ANATOL MICHELSON ATTORNEYS.

Jan. 21, 1969 A. MICHELSON 3,422,658

HIGH VELOCITY FORMING MACHINE Filed Feb. 10, 1967 Sheet 4 Of 4 ANATOL MICHELSON ATTORNEYS.

United States Patent 3,422,658 HIGH VELOCITY FORMING MACHINE Anatol Michelson, Glenolden, Pa., assignor to E. W. Bliss Company, Canton, Ohio, a corporation of Delaware Filed Feb. 10, 1967, Ser. No. 615,161 US. Cl. 72-407 12 Claims Int. Cl. 133% 1/34; B21d 7/06; B21s 7/46 ABSTRACT OF THE DISCLOSURE An impact type forming press which has a pair of opposed platens mounted for reciprocation toward and away from one another. The movement of the platens is synchronized through the use of a mechanical interconnection comprised of a plurality of threaded rods which pass through ball nuts carried in each platen. The platens are moved apart by the use of a mechanical clamp which grips the end of a shaft extending from one of the platens and is moved by a worm gear drive. Energy storing means in the form of a sealed chamber containing precompressed gas is provided to store energy during the period when the platens are moved apart. Release of the mechanical clamp permits the stored energy to drive the platens together at a high velocity.

The present invention pertains to the art of forming metal and the like and, more particularly, to high velocity forming.

More particularly, the invention relates to a high energy impact forming press of the type used in forming metal to a desired configuration, and it will be described with particular reference thereto; however, it is appreciated that the invention has broader application and could be used to press or form any material.

Generally, most impact forming machines are comprised of a pair of press or die platens which are driven together at a high velocity. Each platen carries a forming die. The metal to be formed is placed between the forming dies on the platens prior to their coming together. When the platens are brought together, the metal is impacted into a desired shape. Unless the movement of the two platens is closely synchronized so that the platens are moving together with substantially equal momentum, high impact forces or jars will be transmitted to the press frame and supporting foundation.

In some impact press machines no attempt is made to synchronize the movement and momentum of the press or die platens. Those that do attempt such synchronization use very complicated structure, generally including many hydraulic cylinders, valves, solenoids, complicated electrical equipment, different pressurE systems, etc. As a result, these synchronized impact presses are extremely costly. Further, the maintenance required for such machines is quite extensive, since it is mandatory that all of the various systems work in a strict and exact sequence.

Additionally, in most prior machines difficulties are encountered in recocking or moving the platens to their open position. Separate mechanism is often required to release or trigger the open platens, and accidental triggering sometimes occurs.

The present invention overcomes the above-mentioned disadvantages of the prior high energy presses by providing a press structure in which exact synchronization of the velocity and momentum of the moving press or die platens is achieved simply and relatively inexpensively. The press is designed so that synchronization of the platens is inherent in its operation. This permits the press frame and foundations to be extremely light-weight, since they carry only the weight of the machine parts and are Patented Jan. 21, 1969 not subjected to high impact stresses. Further, no complicated pneumatic or electrical control systems are required to effect synchronization.

The problems of recocking and triggering are also overcome by the use of a simple mechanical clamp and worm type drive mechanism. This aids in achieving a high cycle rate and aslo provides a simple means for regulating the stroke of the platens.

In accordance with the present invention, an impact forming press is provided in which a pair of platens is mounted for reciprocable movement toward and away from each other. Means are provided to drive the platens together and a rotatable force transmitting element is drivingly interconnected between the platens to reduce the difference in the momentum of the platens to a desired level.

A primary object of the present invention is the provision of an impact type forming press capable of high velocity and high cycle rate without the use of complex control systems.

An additional object is the provision of an impact forming press which is recocked and triggered through the use of simple mechanical means.

Another object of the present invention is to provide an impact forming press in which exact synchronization of the momentum of the press platens is achieved without the use of expensive and complicated control systems.

A further object of the present invention is the provision of an impact forming press in which the press frame and foundation structure can be extremely lightweight because of the exact synchonization of the momentum of the forming platens.

A still further object of the present invention is the provision of an impact forming press which is capable of operating at a very high cycle rate.

An additional object of the present invention is the provision of an impact press which can be constructed simply and relatively inexpensively.

A still further object of the present invention is the provision of an impact press having two movable platens which are mechanically interconnected to move at a synchronized speed toward each other.

These and other objects and advantages will become apparent from the following description used to illustrate the preferred embodiment of the invention when read in connection with the accompanying drawings in which:

FIGURE 1 is an elevational view of the preferred embodiment of the present invention, showing the press in its die closed position;

FIGURE 2 is a partial top view of FIGURE 1;

FIGURE 3 is a cross-sectional view taken on line 33 of FIGURE 1;

FIGURE 4 is a cross-sectional view taken on line 44 of FIGURE 1;

FIGURE 5 is a cross-sectional elevational view taken on line 5-5 of FIGURE 4 and showing the internal details of the energy transformer of the present invention;

FIGURE 6 is a detailed view of the actuating clamp used in the present invention;

FIGURE 7 is a cross-sectional view taken on line 7--7 of FIGURE 1 and shows in detail one of the double thrust bearings used in the present invention;

FIGURE 8 is a cross-sectional view taken on line 8-8 of FIGURE 1 and shows in detail one of the ball nut assemblies used in the present invention; and,

FIGURES 9 and 10 are schematic elevations of the press in its open and closed positions, respectively.

Referring now to the drawings wherein the showings are for the purpose of illustrating the preferred embodiment of the invention only and not for the purpose of limiting same, FIGURE 1 shows an overall arrangement of a press A comprised of frame B, press drive assembly C, energy transformer D, and platen movement synchronizing assembly E.

Press A, in general In general, as shown diagrammatically in FIGURES 9 and 10, press A comprises a pair of vertically movable press or die platens 80 and 82 carrying die 79 and 81. The platens are constrained to have equal momentum through a mechanical interconnection. This interconnection could take many forms; however, in the preferred embodiment it comprises four force transmitting shafts 104. Those shafts are connected to the upper and lower platens through drive trains comprised of threads or carnming surfaces formed or mounted on the shaft and coacting nonrotatable ball nut assemblies 126 mounted in each platen.

The threads on upper portion 136 of each shaft 104 are moved in the opposite direction because of rotation of each lower portion 138. In this manner, a force causing movement of one of the platens causes the shafts 184 to be rotated by the ball nut assemblies positioned in that platen. This causes the other platen to be simultaneously moved in the oppostie direction because of rotation of the shaft 184 through the ball nut assemblies positioned in it.

To assure that the platens have equal momentum, the lead of the threads on the upper portion 136 of each shaft is related to the lead of the threads on the lower portion 138, so that the mass X times the velocity V of the upper platen equals the mass Y times the velocity VI of the lower platen. For example, if the mass of each of the platens were equal, then the lead of the threads on both the upper and lower portions of the shaft would also be equal, as shown in the drawings, thereby producing equal velocities of the platens. However, also for example, if the mass of the upper platen were one-half that of the lower platen, then to produce equal momentum, the upper platen would have to move at twice the velocity of the lower platen. This could be accomplished by making the lead of the upper threaded portions twice that of the lower threaded portions. Thus, it is a simple matter to assure that both of the platens have equal momentum. It is apparent. however, that when the velocities are differcut, the platens will not meet in the center of the frame, as shown in the drawings.

The means for applying power to the platens includes an energy transformer D comprised of a sealed housing 39 filled with a precompressed compressible medium such as gas. Extending through the housing 39 are two shafts 84 carrying lower platen 82 and a single shaft 58 carrying upper platen 80. Shaft 58 extends upwardly through housing 39 and is releasably connected to shaft 30 by a clamp assembly 32. Means are provided to selectively drive shaft 30 and clamp 32 up or down.

Upward movement of shaft 58 by clamp 32 and shaft 30 causes platen 80 to likewise move upwardly. As shaft 58 moves upwardly, the enlarged piston portion 69 of shaft 58 moves into housing 39 and compresses the gas therein. As described above, upward movement of platen 80 causes threaded shafts 104 to be rotated and lower platen 82 and shafts 84 to simultaneously move downward. Because of the downward movement of shafts 84, their piston portions 98 likewise enter housing 39 and also act to compress the medium therein. Thus, when the platens have been moved to their open position, as shown in FIGURE 9, the gas in housing 39 is compressed to a high pressure. Subsequently, actuation of clamp 32 to release shaft 58 permits the compressed medium to act against the pistons and move the platens toward one another with great force and at high velocity. Because of the arrangement of threaded shafts 104, the movement of each of the platens is simultaneous and with equal velocity. Consequently, substantially all the kinetic energy of the platens will be transmitted to the workpiece positioned between the platens and substantially none to the press frame and foundation.

Frame B Frame B is a relatively light weight welded structure. As best shown in FIGURE 1, frame B comprises vertically extending corner members 10 formed from angle irons connected at their lower ends by horizontally extending cross braces 12. Positioned at the top of corner members 10 and welded thereto is a housing structure 14. Housing structure 14 is formed from metal plates 16 connected at their upper ends by horizontal cross braces 18.

Drive Assembly C Positioned at the uppermost end of the press and supported on horizontally extending brace members 18 is press drive assembly C. This assembly comprises a horizontally positioned reversible electric motor 20 which is connected through a gearing and screw actuator arrangement to threaded shaft and clamp assembly 32. As best shown in FIGURE 2, motor 20 is connected by a worm 22 and worm gear 24 to a convention screw actuator 26. The rotation of screw actuator 26 through which screw shaft 30 extends causes screw shaft 30 to be moved up or down depending upon the direction of the rotation of worm gear 24.

Connected at the lower end of screw shaft 30 is clamp assembly 32. As best shown in FIGURES 5 and 6, clamp assembly 32 is connected at 34 to screw shaft 30 and comprises a U-shaped clamp frame 36 having two downwardly extending legs 38. Slidably mounted on bearing surfaces 42 of clamp frame 36 are two clamp wedges 40. These wedges are guided by guide grooves 43 formed in legs 38 and are under a continual downward bias by springs 44 positioned at the upper end of each of the wedges. Mounted on each of the legs 38 are release levers 46. These levers are fixedly connected to pins 48 which are freely rotatable in legs 38. Also fixedly connected to pins 48 are quick release levers 50. Quick release levers 50 are provided with a roller 52 mounted on pin 54 at the upper end thereof. Positioned on each side of clamp assembly 32 are adjustable stop members 56.

As can best be seen in FIGURE 6, upward movement of clamp assembly 32 causes release levers 46 to contact adjustable stops 56. Continued upward movement of clamp assembly 32 causes release levers 46 to pivot and press against the lower portion of the clamp wedges thus moving them upwardly out of clamping engagement with clamping surfaces of shaft 58. As a result, shaft 58 is released permitting it to begin movement downwardly. As shaft 58 moves downwardly, a camming member 62, which is connected to shaft 58 and extends horizontally therefrom, contacts rollers 52 moving them and quick release levers 50 outwardly. This causes the release levers 46 to be rotated further upwardly against the clamp wedges 40, thus quickly moving them completely out of engagement with clamping surfaces 62 of shaft 58.

Energy transformer D Energy transformer D is designed to store energy supplied from motor 20 during upward movement of shaft 58. As shown in the drawings of the preferred embodiment, it comprises a sealed box-like compressible medium such as gas; however, it is apparent that the transformer could have other configurations and be positioned in other locations and still function in the same manner.

As best shown in FIGURE 5, housing 39 is formed with upper wall 64, lower wall 66 and side wall 68 and is connected to frame A by being welded to vertically extending frame members 10. Positioned in the center of lower wall 66 and in surrounding relationship to shaft 58 is cylinder forming member 70. Shift 58 is connected in sealing relationship to cylinder member 70 by roll diaphragm 72. Roll diaphragm 72 is joined at its outer periphery to the upper end of cylinder 70 by a clamp member 71 and at its inner periphery to the enlarged piston forming section 69 of shaft 58. The opening in upper wall 64 through which shaft 58 extends is likewise sealed by a roll diaphragm 78. This diaphragm 78 is joined at its outer periphery to walls 64 by collar 76 and at its inner periphery to shaft 58 by collar 79 threaded thereon. Thus, it is apparent that by the above-described arrangement, shaft 58 can have a substantial degree of reciprocation through energy transformer D but is maintained completely sealed relative thereto. Also, it should be noted that by providing the enlarged portion 69 of shaft 58 within the lower cylinder member 70 the pressure surface 74 is provided. As can be seen, upward movement of shaft 58 causes the enlarged piston section 69 of the shaft to enter the housing. This reduces the available volume within the housing and causes the gas therein to be compressed to a high pressure. Release of shaft 58 from its supper or gas compressed position causes it and upper platen 80 supported thereby to be moved downwardly with substantial force by virtue of the compressed gas acting against pressure surface 74.

Also extending through energy transformer D are two lower press platen supporting shafts 84. As best shown in FIGURES 3 and 4, these shafts 84 are positioned equal distances on opposite sides of shaft 58 and extend downwardly parallel thereto. The upper ends of shafts 84 are joined to the energy transformer D for sealed reciprocation relative thereto through connections as best shown in FIGURE 5. These connections are quite similar to those described above with reference to shaft 58 and comprise upper and lower roll diaphragms 88 and 92, respectively. Lower diaphragm 88 is joined at its outer periphery to lower wall 66 by collar 86 and at its inner phriphery to shaft 84 by sleeve 94. Upper diaphragm 92 is joined at its outer periphery to the lower end of cylinder forming member 90 by clamp rnember 91. The inner periphery of diaphragm 92 is joined to shaft 84 by being gripped between Sleeve 94 and piston forming member 98 attached to shaft 84 by nut 96.

In view of the above, it can be seen that shafts 84 can partake of a substantial amount of reciprocation relative to the housing 39 and yet are maintained in completely sealed relationship relative thereto. Further, it should be noted that downward movement of shafts 84 causes piston forming members 98 to be moved into housing 63 and thereby compress the gas therein. Release of shafts 84 from their lower or gas compressed position permits the compressed gas acting against pressure surfaces 100 to move the shafts 84 and the lower platen 82 supported thereby upwardly with substantial force. It should be pointed out that the combined total effective area of pressure surfaces 100 should be related to the effective area of pressure surface 74 so that the energy input to each of the platens 80 and 82 is substantially equal.

As described above, the seal connections between housing 39 and shafts 58 and 84 are preferably roll diaphragms because there is substantially no friction and no chance for leakage with this type of seal. However, it is apparent that other types of seals such as bellows type diaphragms or packed joints could be used.

Also mounted within the housing 63 of energy transformer D are four thrust bearing assemblies 102. As can be seen in FIGURES 3 and 4, these four thrust bearing assemblies are equally spaced about the center of housing 63. Rotatably mounted within each of the thrust bearing assemblies and supported thereby are threaded shafts 104. Threaded shafts 104 serve to synchronize the movements of upper and lower press platens 80 and 82 in a manner to be subsequently described.

Referring now to FIGURE 7, it can be seen that each thrust bearing assembly 102 comprises an outer housing member 106 welded at its top and bottom to upper and lower walls 64 and 66 respectively of housing 63. The upper and lower ends of housing 106 are closed by closure members 118 and 122, respectively. Positioned within the interior of housing 106 are thrust bearings 114 and 116. Shaft 104 is supported by annular thrust bearings 114 and 116 through a thrust collar 108 which is attached to the upper end of shaft 104 by a sleeve and clip ring 112. Also mounted in the housing 106 is a ball bearing 120 which serves to maintain shaft 104 centered relative the thrust bearings. Shaft 104 is sealed at its point of exit from the housing 106 by a seal member 124.

Platen movement synchronizing assembly E Referring now to FIGURES 1 and 5, upper and lower press platens 80 and 82 are shown carried by shafts 58 and 84 respectively. Shafts 58 and 84 extend upwardly and are connected to energy transformer D as described above.

As shown in FIGURE 5, platens 80 and 82 are constrained to have equal and opposite momentum by shafts 104 in the manner previously explained. Shafts 104 extend downwardly from enerby transformer D and are connected to the upper and lower platens through ball nut assemblies 126. As shown in FIGURE 1, the lower ends of shafts 104 are mounted for free rotation in bearing blocks 140 which are connected to cross brace members 12 of frame A.

Referring now to the ball nut assemblies 126, it can be seen in FIGURE 4 that each of the upper and lower press platens are provided with four of these assemblies located generally at their outer corners. As shown in detail in FIGURE 8, each of the ball nut assemblies comprises a main nut-like member 128 mounted in the press platen. Member 128 is mounted to have some axial movement relative the press platen but is fixed against rotation relative thereto. Mounted interiorly of member 128 are a plurality of balls 130. These balls 130 serve as the threads and engage the threaded portion of shafts 104. At the upper end of member 128 is connected a retaining collar 132. This collar is engaged at opposite sides by conventional fluid springs 134 which function to absorb the kinetic energy of the ball nut assemblies when the press platens are impacted.

Operation Assuming the press is in the platens closed position, as shown in FIGURE 10, the motor 20 is started, driving the threaded shaft 30 and clamp assembly 32 downwardly into clamping engagement with the upper end of shaft 58. Motor 20 is then reversed, and clamp assembly 32 begins to move upwardly. Because of the downward bias on clamp wedges 43, the shaft 58 is gripped tightly. Continued upward movement increases the clamp pressure applied to shaft 58. As shaft 58 moves upwardly, upper platen 80 moves upwardly also. This causes enlarged piston portion 69 of shaft 58 to move into housing 63 of energy transformer C compressing the gas contained therein. Simultaneously, lower platen 82 is moved downwardly by virtue of the rotation of threaded shafts 104 caused by nonrotatable ball nut assemblies 126 in the upper platen 80. As the lower platen 82 moves downwardly, the piston portions 98 on the upper ends of shafts 84 move into housing 63 of energy transformer D, further compressing the compressible gas contained therein. When the press platens have been opened to substantially their full open position, a stop 146 on upper platen 80 contacts rnicroswitch 144 which, through conventional wiring not shown, causes motor 20 to be stopped. At this time, the workpiece that is between the dies from the previous press stroke is removed and a new workpiece is placed on lower die plate 81. Motor 20 is then switched on again and continues to move the platens apart. When it has moved the clamp assembly 32 to a position at which adjustable stops 56 are contacted, continued upward movement of clamping assembly 32 causes shaft 58 to be released in the manner previously described. Release of shaft 58 permits the com- 7 pressed gas in chamber housing 39 to act against pistons 98 and piston-forming section 69 causing the upper and lower platens to be driven together at a high velocity. Continued upward movement of clamping assembly 32 causes stop finger 150 carried on clamp housing 36 to contact limit switch 148 and shut off motor 20.

The invention has been described in great detail sufiicient to enable one skilled in the art of presses to duplicate the invention. Obviously modifications and alterations of the preferred embodiment described will occur to others on the reading and understanding of this specification. It is my intention to include all such modifications and alterations as part of my invention insofar as they come within the scope of the appended claims.

Having thus described my invention, I claim:

1. In an impact press comprising: a frame, a first and second platen, means for mounting said platens on said frame for movement toward and away from each other, and means for applying power to at least one platen for driving said platens together at high speed, the improvement comprising:

a force transmitting element;

a first drive train drivingly connecting said element to said first platen;

a second drive train drivingly connecting said element to said second platen; said first drive train including, a first member connected to said first platen and reciprocable therewith, and a first rotatable drive member drivingly connected between said first member and said element;

said second drive train including, a second member connected to said second platen and reciprocable therewith, and a second rotatable drive member drivingly connected between said second member and said element;

said first and second drive trains cooperating with said force transmitting element and said platens so that movement of one of said platens causes the drive train associated therewith to drive said force transmitting element and the drive train associated with the other of said platens, to produce movement of said other platen.

2. The impact press of claim 1, wherein said element and said first and second rotatable drive members are integrally formed.

3. The impact press of claim 1, wherein said element comprises a rotatable rod.

4. The impact press of claim 1, wherein said element comprises a rotatable rod and said first and second rotatable drive members comprise threads formed thereon.

5. The impact press of claim 1, wherein said drive trains include ball nut assemblies and threads on said force transmitting element.

6. The impact press of claim 1, wherein said first and second members are ball nut assemblies.

7. The impact press of claim 1, wherein said means for applying power to said one platen includes means forming a sealed chamber filled with a compressible medium.

8. The impact press of claim 7, wherein said means for applying power to said one platen includes, at least one shaft means connected to one of said platens and passing through said chamber, means sealing said shaft means at its entrance and exist from said chamber but permitting said shaft to have limited reciprocation therethrough, said shaft means including a piston portion adapted to reciprocate into said chamber to compress the medium therein, and means for selectively moving said Shaft means relative said chamber.

9. The impact press of claim 8, wherein said means for selectively moving said shaft means is releasably connected thereto by a clamp means, and including means to release said clamp means in response to a predetermined movement thereof.

10. The impact press of claim 8, wherein said means for applying power to said one platen further includes a worm gear mechanism.

11. The impact press of claim 9, wherein said sealing means comprises diaphragm members.

12. The impact press of claim 9, wherein said means to release said clamp are adjustable for varying the amount of movement necessary to release said clamps.

CHARLES W. LANHAM, Primary Examiner.

G. P. CROSBY, Assistant Examiner.

U.S. Cl. X.R.

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