US2635490A - Apparatus for forming articles of comminuted metal - Google Patents

Description

C. C. KINKER A ril 21, 1953 APPARATUS FOR FORMING ARTICLES OF COMMINUTED METAL Filed Feb. 18, 1948 6 Sheets-Sheet l INVENTOR. Clarence C. M'nker BY fflNEYS E April 21, 1953 c. c. KlNKER 2,635,490

APPARATUS FOR FORMING ARTICLES OF COMMINUTED METAL Filed Feb. 18, 1948 6 Sheets-Sheet 2 E'g I INVEIYTOR. Clarence C. A mkeh 3 XTT RNEYS C. C. KINKER April 21, 1953 APPARATUS FOR FORMING ARTICLES OF COMMINUTED METAL Filed Feb. 18, 1948 6 Sheets-Sheet 5 lNVE NToR. Clarence C. hm/rer' April 21, 1953 c. c. KINKER 2,635,490

APPARATUS FOR FORMING ARTICLES OF COMMINUTED METAL Filed Feb. 18, 1948 6 Sheets-Sheet 4 E 9 E IN VEN TOR.

C/arence C. Kin/(en April 21, 1953 c. c. KINKER 2,635,490

APPARATUS FOR FORMING ARTICLES OF COMMINUTED METAL Filed Feb. 18, 1948 6 Sheets-Sheet 5 jfz'q. I

INVENIOR. Clarence C K/nker' BY W AT OR NEYS E C. C. KINKER A ril 21, 1953 APPARATUS FOR FORMING ARTICLES OF COMMINUTED METAL Filed Feb. 18, 1948 6 Sheets-Sheet 6 INVENTOR Clarence C. llmker A E ATTOENEYS Patented Apr. 21, 1953 APPARATUS FOR FORMING ARTICLES 02* COMMINUTED METAL Clarence C. Kinker, Defiance, Ohio, assignor to Baldwin-Lima-Hamilton Corporation, a corporation of Pennsylvania Application February 18, 1948, Serial No. 9,147 In Canada September 8, 1944 '7 Claims.

This invention relates to a method of and apparatus for compacting powdered or comminuted material to form coherent bodies therefrom. This application is a continuation-inpart of application Serial No. 506,786, filed October 18, 1943, and now abandoned.

The amount of compaction that may be achieved in a press depends to a large extent upon the maximum instantaneous pressure applied to the material within a die forming part of the press. To a lesser extent the amount of compaction is also influenced by the duration of time during which the material is held under pressure.

The pressure that may be exerted during the compacting of a material by an ordinary hydraulically operated or crank-operated press is determined by the load carrying capacity of the frame of the press. As ordinarily constructed, the frame of the press must be capable of sustaining a force equal to or greater than the maximum pressure or force applied to the material being compacted. The strength of the frame thus limits the compacting pressure that may be obtained in an ordinary press. The principal object of this invention is to provide a method of and apparatus for compacting material in which method the maximum instantaneous force that is applied to the material is much greater than the average force exerted by the press or transmitted through the frame of the press.

Another object of the invention is to provide a compacting apparatus in which the compacting force for a given cycle of operation is divided into a series of short-duration high-pressure impacts that efiect a compacting action similar to that produced from successive blows of a hammer.

A still further object of the invention is to efiect a compaction of the material by holding the material under a low, sustained pressure while subjecting it to a series of high pressure impacts.

A still further object of the invention is to incorporate mechanism into a crank-operated press such that the material being compacted is subjected to a series of impacts during each revolution of the crank operating the press.

These and other objects and advantages are apparent from the following description of a preferred form of apparatus for carrying out the invention.

The invention consists in an improved method or compressing material comprising the steps of applying force to the material through a path that includes stressed resilient members and a heavy body, and stepwisely shortening the portion of the force transmission path between the heavy body and the material, which shortening results in stepwise movement of the heavy body toward the material accompanied by at least a momentary extension of the resilient members and the application of an impact force to the material at the termination of each stepwise movement of the heavy body.

The invention also includes an improved apparatus for carrying out the improved method of compressing material. In a preferred form, the improved apparatus includes a press in which a movable head is reciprocated by a crank and connecting rod mechanism. The movable head carries a punch that is adapted to enter a die supported in another portion of the press to compact material within the die. The punch is attached to the movable head by mechanism capable of permitting a controlled stepwise reduction in the distance between the punch and the movable head even though a substantial amount of force is being transmitted from the head to the punch. The movable head is connected to and driven from the crank and connecting rod driven mechanism by heavy preloaded coil springs constituting resilient members. The adjustment of .the Various components of the press is such that in a regular pressing operation the crank and connecting rod mechanism drives the head to lower the punch into the die and to apply force to the material within the die. The stroke of the connecting rod driven mechanism is such that the punch engages the material in the die and the movement of the head is consequently arrested before the crank reaches its dead center position. The continued motion of the crank and connecting rod mechanism is permitted by compression of the heavy coiled springs beyond their preloaded condition.

During that portion of the stroke in which the springs are compressed beyond their preloaded condition the mechanism connecting the punch to the movable head is operated to permit one or more stepwise reductions in the distance between the punch and the movable head thereby producing stepwise movements of the movable head toward the now stationary punch (held stationary by contact with the material in the die). During each step of the stepwise reduction in distance, the resilient members-the heavy preloaded springs-accelerate the head toward the punch and the kinetic energy acquired by the head during such stepwise movement is imparted to the punch as the mechanism connecting the punch to the head arrests the movement of the head at the termination of each such stepwise movement.

This sudden arresting of the movement of the head at the termination of each stepwise movement produces high impact forces that facilitate the compression of materials within the die. Each stepwise movement of the head, as permitted by the stepwise reduction in distance between the movable head and the punch, produces a corresponding extension of the compressed resilient members-the springs-which extension may be momentary or continued depending upon the movement of the connecting rod driven mechanism occurring during each stepwise movement. If the movement of the connecting rod mechanism during each stepwise movement exceeds the length of the stepwise reduction in distance between the punch and head the extension of the springs is merely momentary while if the connecting rod mechanism is near the end of its stroke the stepwise movement of the head results in a net increase in extension of the springs. Successive steps of the stepwise movement of the head with respect to the punch and connecting rod mechanism may occur as long as the resilient membersthe springs-are compressed by the connecting rod mechanism beyond their preloaded condition.

In its preferred form the mechanism connecting the punch to the movable head for permitting the stepwise reduction in distance between these elements includes a hydraulic cylinder mounted in the head and a piston within the cylinder the rod of which is connected to the punch. During that portion of the press cycle during which the punch is not in contact with the material in the die hydraulic fluid from a source maintained under pressure flows into the hydraulic cylinder until the piston thereof is driven to the limit of its stroke. During that portion of the press cycle when the punch is in contact with the material in the die and the heavy springs have been compressed beyond their preloaded condition the fluid within the hydraulic cylinder, which is now under high pressure, is permitted to escape in intermittent metered quantities the escape of each particular quantity resulting in one step of a series of stepwise movements of the piston within the cylinder in a direction that tends to reduce the distance between the punch and the movable head. Because of the magnitude of the forces involved the hydraulic cylinder and piston are preferred as mechanism for permitting stepwise movement between the punch and the resiliently driven head.

A metering device incorporating a metering piston is included in the hydraulic system between the hydraulic cylinder in the movable head and an accumulator that maintains pressure on the hydraulic fluid. Furthermore, a check valve connected in parallel to the metering device is included to permit fiow of fluid from the accumulator directly to the hydraulic cylinder when the punch is not in contact with the work and to prevent reverse flow when the pressure in the hydraulic cylinder builds up as the I punch engages the material in the die. Thus hydraulic fluid flows from the accumulator to the hydraulic cylinder through the check valve when the pressure in the accumulator exceeds that in the hydraulic cylinder and intermittently flows in the reverse direction through the me- 4 tering device when the pressure in the hydraulic cylinder exceeds that in the accumulator.

In the drawings:

Figure I is a side elevation, with parts broken away, of the essential mechanism of a press constructed according to the invention.

Figure II is a schematic illustration showing the cooperation of the variou elements of the press.

Figure III is a side elevation, with parts shown in section, of a feeding mechanism suitable for feeding preforms into the press.

Figure IV is a fragmentary plan view as seen from the line IVIV of Figure III.

Figure V is a fragmentary end elevation as seen from the line V-V of Figure III.

Figure VI is a plan view illustrating the feeding mechanism for advancing the preforms to the press and removing the previously formed article.

Figure VII is a fragmentary vertical section taken along the line VIIVII of Figure III.

Figure VIII is a fragmentary detail as seen from the line VIIIIVIII of Figure III.

Figure IX is an enlarged elevation, with parts broken away and parts shown in section, of the upper portion of the improved press.

Figure X is a fragmentary elevation showing a portion of the driving mechanism of the press and a portion of the hydraulic system.

Figure In is a perspective view, with parts broken away, showing a metering device forming part of the hydraulic system of the improved press.

These specific figures and the accompanying description are intended merely to illustrate the invention but not to impose limitations on the claims.

Briefly described, the improved method is as follows: The comminuted material, preferably in preformed bodies (called preforms), is first passed through a heating furnace to raise the temperature to a predetermined point. The preforms are then successively fed into registration with cooperating dies which fashion and compress the same. These operations may, if desired, be carried out in a non-oxidizing atmosphere and the formed bodies, when successively ejected from the die, may be passed through a liquid seal which also forms a cooling bath. When a preform is fed into registration with the die, a lower plunger constituting the bottom of the die chamber is depressed to lower the preform into the die, and an upper punch is driven into the die to produce the desired compression. During this compressing operation any entrapped air must be eliminated by removing it by compression or force from between the particles or through the pores of the preform and it has been found advantageous for this and for other reasons hereafter described to deliver a succession of hammer blows or impacts, instead of continuous pressure.

The press constructed according to the invention and illustrated in the accompanying figures includes a frame or housing I and a movable head mechanism 2. The head mechanism 2 is carried on a plurality of vertical tie rods 3 that are slidably mounted in the frame I and are rigidly connected near their lower ends to a crosshead 4. The crosshead 4 is connected through a connecting rod 5 to a crank shaft 6 that is journaled in the lower part of the frame I. The lower ends of the tie rods 3 are guided in bearings I attached to the frame I which bearings absorb the side thrust produced by the connecting rod 5 and thus prevent any binding of the tie rods within the frame I.

A large gear 5 rigidly attached to the crank shaft 6 meshes with and is driven by a pinion 9 mounted on an intermediate or pinion shaft I0. The shaft it also carries a large pulley H the heavy rim of which serves as a flywheel. The large pulley l l is driven through V-belts I2 from a small pulley l3 mounted on an output shaft M of a variable ratio transmission I5. An electrical motor it connected to the input of the variable ratio transmission I5 supplies the power to drive the press.

The head mechanism 2 is slidably mounted on the tie rods 3. The head mechanism includes a heavy casting I! having ears !8 through which the tie rods 3 are slidably fitted. A plurality of heavy helical springs 49 mounted on the upper ends of the tie rods 3 are compressed between lower spring seats resting on the upper surfaces of the ears 1% of the heavy casting i1 and upper abutments 2| that engage nuts 22 threaded onto the upper ends of the tie rods 3. The helical springs 19 urge the casting i1 downwardly on the tie rods 3 until the lower surfaces of the ears l8 rest on shoulders 23 formed in the tie rods 3. The shoulders 23 accurately position the head mechanism 2 with respect to the tie rods 3 while permitting compression of the springs l9 beyond their preloaded condition whenever the force applied through the tie rods 3 exceeds the preload force of the compressed springs IS.

The head mechanism 2 includes a punch 24 that cooperates with a die set into the upper surface of the frame I. A ram 21 (Figure II) forming the lower portion of the die is actuated by a cam mechanism included with the crank shaft 6 and arranged so that the ram 21 is firmly supported by the frame during a pressing operation and is subsequently lifted by the cam mechanism to eject the finished article from the die.

The punch 24, while carried in the head mechanism 2, is movable with respect thereto and the load forces from the punch 24 are carried to the casting ll by means of a hydraulic piston and cylinder that is connected through valving and a conduit system 25 to an accumulator 26 that serves as a reservoir for the oil or other hydraulic fluid used in the system.

Referring now to Figure II, the punch 24 is shown mounted on the lower end of a piston rod 28 of a piston 23 mounted in a hydraulic cylinder 35 formed in the casting ll of the head mechanism 2. The hydraulic cylinder 30 is coning I? and slidable on a tube 34 that, being mounted on the frame I, extends completely through the sleeve 33. A hole 35 drilled in'the side of the tube 34 provides hydraulic communication from the interior of the tube 34 to the interior of the sleeve 33 which is connected directly to the pipe 3|. This arrangement provides hydraulic communication between the cylinder 30 mounted in the head mechanism 2 and other portions of the hydraulic system mounted on the frame I without restricting or interfering with relative movement between the head mechanism 2 and the frame I.

The sleeve 34 mounted on the frame I is connected through a valve 36 to the conduit system 25 leading to the accumulator 26. A metering valve 31 is included in one branch 38 of the conduit system 25 while a check valve 39 is included in another branch 40. The function of these elements in securing stepwise movement of the punch 24 and piston 29 with respect to the head mechanism 2 is described more fully in connection with the description of Figures IX, X and XI.

Still referring to Figure II, the pinion shaft l0 mounted in the frame I, by way of bevel gears 4|, feed shaft 42 and bevel gears 43, drives a shaft 44 carrying feeding cams and 46. The gear ratio through the bevel gears 4| and 43 is such that the cam shaft 44 rotates in synchronism with the crank shaft 6.

The feed cam 45 operates a feeding mechanism 4'! that transfers preforms 48 from an inclined trough 49 into the lower end of a tube 50 which is inclined from the horizontal and which leads through an electrically heated furnace 5|. As each new preform 48 is pushed into the lower end of the inclined tube 50 the preform at the otherthe upper-end of the tube 50 leaves the tube and slides down a curved chute 52 into position to be engaged by a feeding mechanism 53 (Figure III) carried on the ends of feed rods 54. The feed rods 54 are driven by a linkage including a lever 55 that engages the feeding cam 56.

In the event that the preforms must be protected from oxidation during the heating and pressing operation, a protective atmosphere may be supplied through a tube 56 leading into the inclined tube 50 near its upper end. Furthermore, the casting ll of the head mechanism 2 may be provided with a downwardly-directed skirt 5'! which in cooperation with a housing 58 completely encloses the region through which the heated preforms pass in going to and from the die. As the preforms leave the die they slide down an inclined chute 59 the lower end of which is immersed beneath a cooling liquid contained in a tank 60.

The feeding mechanism is shown in detail in Figures III to VIII inclusive. Referring to Figures III, IV and V, the preforms 48 as they roll rown the inclined trough 49 are successively engaged by a finger 51 extending from a carriage 62 that is slidably mounted on a track 63. The carriage 52 including the fingers 6| forms part of the feeding mechanism 47 and is driven through a linkage 54 including a lever 65 having a roller 66 engaging the feed cam 45. A tension spring El connected between the lever 65 and a portion 68 of the frame of the machine holds the roller 66 in contact with the cam. To prevent damage in the event that the preforms jam within the tube 50 a yieldable connection 69 is included between portions of the link 64. The yieldable connection 59 includes a spring 10 arranged to urge the adjacent ends of the portions of the link 54 into. contact with each other and hold them in contact unless the tension in the link 54 exceeds the force exerted by the spring 10. Any excess force causes the spring I0 to yield so that none of the mechanism is overloaded by a failure of the preforms to properly feed through the furnace.

The inclined tube 56 extends through the electrically heated furnace 51 which includes heating elements enclosed in an insulating material that confines the heat within the furnace. The temperatures maintained within the tube 50, particularly near its upper end, are sufiicient to heat the preforms to a softening temperature so that they may be readily formed into final shape by compression within the die of the press. Since the preforms may be of different thicknesses depending upon the object to be made,

a guide member H securely mounted on adjusting screws 12 and extending downwardly through the curved chute 52 is provided to prevent a y possibility of jamming as the preforms slide down the chute.

The feeding mechanism 53 and its drive are shown in considerable detail in Figures VI, VII and VIII. The feeding mechanism 53 includes a crosspiece 13 that is slidably mounted on the feed rods 54 and that includes stop pins 14 arranged to strike fixed abutments 15 during the retraction of the feed rods 54. A pair of helical springs 16 carried on the ends of the feed rods 54 urge the crosspiece 13 toward its normal rest position as shown in Figure VI.

The feed rods 54 also carry a second crosspiece 11 which includes a tongue 18 that, travelling through a slot in the lower end of the curved chute 52 as the feed rods are advanced, engages the rear surface of a preform and urges it toward guide pieces 79 of the first crosspiece I3 so that the preform is accurately positioned as the feed rods 54 advance it into registration with the die cavity. A pair of adjustable shoulders 80 mounted on the feed rods 54 are arranged to contact the crosspiece 13 just before the preform is gripped between the tongue 18 and the guide pieces 19 so that the preform is free to drop into the die when the ram 21 is lowered. The forward motion of the crosspiece 13 also serves to remove the previously completed object after it has been ejected from the die by the operation of the ram 21.

The feed rods 54 are interconnected by a crosshead 8| which in turn is connected by a link 82 to the upper end of the lever 55. The lever 55 is driven forward by the feed cam 46 and is retracted to its normal position by a spring 83 that is similar to the spring 61 cooperating with the lever 65. As may be seen in Figure VIII, the roller 66 consists of a ball bearing mounted on a stud extending from the lever 65. The lever 55 is provided with a similar roller to contact the cam 46. This furnace and feeding mechanism provides a simple and efficient structure for heating the preforms and for transferring them to the die of the press and for removing the finished articles from the path of the punch 24 after they have been ejected from the die.

It was mentioned previously that the capacity of a press for effecting compaction of a material confined within its die may be materially increased without increasing the size of the frame of the press if the compacting effort is 4 divided into a series of blows or impacts of relatively high force and short duration. It was also mentioned that this effect may be obtained by connecting the head of the press to tie rods .by means of heavy preloaded resilient members and of connecting the punch to the head mechanism through a structure that is capable of allowing stepwise movement of the punch with respect to the head mechanism. In operation, the heavy preloaded resilient members hold the head structure against the shoulders on the tie rods until the punch engages the material in the die with a force equal to or greater than that exerted by the preloaded members or springs. Further downward travel of the tie rods as the crank shaft continues its rotation serves to compress the springs beyond their preloaded condition and to apply a force to the material within the die equal to that transmitted through the press. While the springs are held in this .and the head casting l1.

8 stressed condition, the head mechanism and the punch are allowed to approach each other in a stepwise manner. Since the punch is held substantially stationary by the material within the die the head mechanism executes the stepwise movements.

During the entire pressing cycle the force of the compressed springs is transmitted through the head mechanism to the punch. The amount of force transmitted at any instant depends upon the instantaneous acceleration of the head as it executes the steps of the stepwise movement. Thus at the start of any such stepwise movement a greater part, if not all, of the spr n force is utilized in overcoming the inertia of the head and very little force is transmitted to the punch. At the end of each stepwise movement the punch is acted upon by a force equal to that exerted by the springs plus the force necessary to decelerate the head mechanism. Since the force transmitted by the springs may be a substantial portion of the capacity of the frame of the press, it follows that the maximum instantaneous force at the end of any stepwise movement may be much greater than the force that the press is capable of continuously exerting.

The springs l9 acting between the nuts 22 at the upper ends of the tie rods 3 and the head casting I! serve as the resilient members that are preloaded and that are compressed beyond their preloaded condition during a portion of the travel of the tie rods 3. The hydraulic piston 29 operating within the cylinder constitutes a portion of the means for effecting a stepwise relative movement between the punch 24 Each stepwise relative movement is effected by withdrawing a metered quantity of fluid from the cylinder 30.

Referring to Figure IX, the upper portion of the press including the head mechanism 2 is shown in considerable detail. As may be seen in this view, the ram 21 operates within a ringshaped member 84 that is set into the frame I and which constitutes the die in which the preform is compacted or forged to form the finished article. The punch 24, which cooperates with the die ring 84 and the lower ram 21, is shown in its lowermost position with respect to the head casting I! while the head mechanism 2 including the casting I I is shown at its uppermost position. In this position the piston 29 of the hydraulic cylinder 30 is at the lower limit of its stroke at which point its lower surface, adjacent the piston rod 28, rests against the lower end of the cylinder. The piston 29 is provided with packing rings 85 that are secured by an upper plate 86 forming the upper end of the piston 23. A portion of the piston rod 28 protrudes through the upper plate 86 in position to engage a lower end of a stop screw 8'! threaded through a cap 88 that closes the upper end of the cylinder 30. This stop screw 81 is used to lock the punch 24 with respect to the head mechanism 2 whenever it is desired to operate the press without employing the stepwise movement of the head.

Hydraulic fluid that is permitted to escape from the cylinder 30 flows through the pipe II and the slidable connector 32. As may be seen in Figure IX, the ends of the sleeve 33 forming the slidable part of the connector 32 are furnished with packings 89 that are a close fit on the tube 34. The hydraulic fluid flows from the pipe 3| into that portion of the sleeve 33 surrounding the tube 34 and in through the hole vided with a cylindrical bore and two annular cavities 92 and 93 extending radially outward from the bore. The lower one of the cavities, the cavity 92, is connected directly to the pipe 99 leading to the slidable connector 32 while the other cavity, the cavity 93, is connected directly to the conduit system 25 leading to the accumulator 26 and the metering valve 31. A valve stem 94 extends through the bore in the sleeve 9| and the ends of the sleeve are closed by packing rings 95 and 93 so that there can be no leakage of fluid. The valve stem 94 is reduced in diameter through a portion of its length sumcient to span the space between the annular cavities 92 and 93 so that when the valve stem 94 is at one limit of its travel fluid may flow from the pipe 99 through the valve 39 to the conduit system 25 or in the reverse direction.

When the valve stem 99 is raised to the position shown in Figure IX, the full diameter portion of the valve stem 94 closes off that portion of the bore between the annular cavities 92 and 93 so that fluid flow is interrupted.

The upper end of the valve stem 94 is reduced in diameter and extends upwardly through a hole in a lug 9'! extending laterally from one of the tie rods 3. The upper end of the valve stem 94 is provided with a collar or cap 98 that contacts the upper surface of the lug 99 to raise the valve stem 94 to the position shown when the tie rods and head mechanism 2 approach the upper end of their range of movementv The valve stem 99 remains in its upper position during the first part of the downward travel of the tie rods 3 and until a hollow nut 99, slidably mounted on the reduced diameter portion of the valve stem 94 and threaded into the lug 91, strikes a shoulder I99 at the bottom of the reduced diameter portion of the valve stem 94. When the hollow nut 99 strikes the shoulder I99 the valve stem 94 is driven downwardly until fluid flow between the pipe 99 and conduit system 25 is established.

The adjustment provided by the hollow nut 99 in relation to the lug 91 and valve stem 94 permits the exercise of control over the escape of fluid from the hydraulic cylinder 39 and thus permits the stepwise movements of the head mechanism .to be limited to a portion of the cycle less than that during which the springs I9 are compressed beyond their preloaded condition.

A saw slot extending from the end of the lug 9! into the hole into which the hollow nut 99 is threaded permits the nut 99 to be clamped securely in adjusted position. The clamping is effected by means of a bolt extending through a transverse hole I9I in the end of the lug 91 and controlled by a handle I92 (shown in Figure I).

Referring now to Figures II and X, the hydraulic system comprising the hydraulic cylinder 39, the slidable connector 32 and the valve 36 mounted on the frame I is connected through the conduit 25 and through either the metering valve 3'! or the check valve 39 to the accumulator 29. is shown mounted on the case of the variable speed transmission 55 and includes an upwardlydirected piston I93 having interior passages I94 connecting a pipe I95 (leading to the metering valve 3'! and check valve 39) to the space with- The accumulator 23 (Figure X) oil in the accumulator 29 above the piston I93. A cylinder I99 is slidably mounted on the piston I93 and is urged downwardly by a plurality of springs I91 which are compressed between ears I98 at the lower end of the cylinder I96 and a spacer plate I99 that is secured to the upper ends of a plurality of rods H9 which serve to guide the cylinder I96 and the springs I91. The force of the springs I91 plus the weight of the cylinder I96 maintains a certain amount of pressure upon the hydraulic fluid within the accumulator 29 while permitting flow either to or from the hydraulic cylinder 39 mounted in the head mechanism 2. If the pressure within the accumulator 26 is greater than the pressure within the hydraulic cylinder 39 and the valve 39 is open hydraulic fluid flows from the accumulator through the pipe I95, the check valve 39 and the conduit system 25 leading to the cylinder 39 and the piston 29 is driven to its lower limit of travel with respect to the head casting IT. The check valve 39 prevents reverse flow when the pressure in the hydraulic cylinder 39 builds up as the punch 24 compacts material within the die ring 84.

During that portion of the cycle when material is being compacted within the die and the force acting on the punch 24 is suihcient to lift the head casting I! off the shoulders 23 of the tie rods 3 and thus compress the springs I9 beyond their preloaded condition fluid is permitted to flow from the conduit system to the accumulator 26 by way of the metering valve 31. The metering valve 3'! is driven by the output shaft I4 of the variable speed transmission I5 and is designed to permit the passage of a succession of metered quantities of fluid from the conduit system 25 to the accumulator 26.

The metering valve 3! is shown in detail in Figure XI. This valve comprises an outer cylindrical casing III that is attached to an end of the casing of the variable speed transmission IS in line with the output shaft I4. A rotatable sleeve IIZ carried in the cylindrical housing III at its closed end is provided with a transverse groove II3 so that it may be driven by a key or tenon H4 formed on the end of the output shaft I I of the variable speed transmission.

An axially slidable piston H5 is contained within the rotatable sleeve H2 and is urged toward the shaft-driven end of the sleeve by a helical spring H9 compressed between an end of the piston H5 and a cap IIl closing the end of the rotatable sleeve H2. The piston II5 includes a reduced diameter emension I I8 and a perforated or grooved guide portion I I9 that, by striking the closed end of the rotatable sleeve H2, limits the spring-urged travel of the piston I I5. An adjusting screw I29 threaded through the can II'I serves as a limit stop at the other end of the travel of the piston I I5.

Hydraulic fluid coming from the hydraulic cylinder in the head mechanism 2 through the conduit 25 enters a port I2I in the side of the cylindrical casing III which port I2I is in the same transverse plane as a plurality of holes or ports 522 of the sleeve H2 and that are adapted to successively register with the port IZI as the sleeve I42 turns in the housing III. The cylindrical housing I I I is provided with a second port I23 in the same transverse plane as the port I2I and which is connected through a pipe I24 leading to the pipe I95 and the accumulator 26. A third outlet or port I25 of the housing III is connected through a short pipe I29 to the pipe I24 and thus is connected to the accumulator 26.

The inlet port I2I from the conduit system 25 and the discharge port I 23 connected to the pipe I24 and the accumulator 2B register successively but not simultaneously with the ports I22 of the sleeve I I2, which latter ports communicate with the space surrounding the extension IIB of the piston I I5. When one of the ports I22 registers with the inlet port I2I, assuming that a high pressure exists within the cylinder 30, hydraulic fluid flows into the space surrounding the reduced diameter extension II8 of the piston H5 and acts against the end of the piston H5 and between the end of the sleeve II2 and the perforated or grooved guide portion II9 to drive the piston II5 against the compression of the spring I I6 until the piston [I5 is stopped by the screw I20. During this travel of the piston II5 fluid is discharged from the chamber containing the spring IIB through radial holes I21 leading to an annular groove I28 that continuously registers with the port I25 and into the pipe I26 and thence to the accumulator 26.

A moment later, as the sleeve I I2 continues its rotation, one of the ports I22 registers with the discharge or outlet port I 23. At this time the spring II6 drives the piston to its former position, thereby circulating fluid out through that one of the ports I22 in registry with the port I23 through the pipes I24 and I25 and through the annular groove I28 and holes I2! and into the chamber containing the spring I I6. This flow of fluid is produced by the spring I I6 and the pressure in the accumulator 26 does not affect this flow because it merely maintains a. substantial pressure throughout the system and all portions of the metering valve are subjected to that pressure during this portion of the operation. There are as many cycles of operation of the piston I I 5 within the rotatable sleeve II2 per revolution of the sleeve as there are ports I22 that are adapted to successively register with the inlet and discharge ports I2I and I23 respectively. Furthermore, since the shaft I4 rotates much faster than the crank shaft 6, it follows that there may be a number of operations of the piston II5 during that portion of the cycle durin which the springs I are compressed beyond their preloaded condition while compacting material within the die.

The quantity of fluid passed by the metering valve 31 during each oscillation of its piston H is controlled by the adjustment; of the screw I20 that serves to limit the travel of the piston II5. This adjustment, by regulating the quantity of fluid released from the cylinder 30 per operation, has the effect of controlling the length of each of the stepwise movements of the head casting I! with respect to the punch 24 and thus the magnitude of the impact force applied to the punch at the end of each such stepwise movement. If a relatively long stroke of the piston H5 is permitted the head mechanism 2 including its casting I1 acquires a relatively high velocity during the stepwise movement; and as the piston H5 is suddenly stopped by striking the adjusting screw I20 the pressure throughout the hydraulic system suddenly rises to a high value as the piston 29 within the cylinder 30 arrests the movement of the head mechanism 2. The high pressure acting against the piston 29 transmits the impact force to the punch 24 and the work in the die. The action is much like a hammer operating through a punch. The relative movement of the head With respect to the punch corresponds to the travel of the hammer, while the sudden stopping of fluid flow corresponds to the usual mechanical contact between the hammer and the driven punch. The results are quite similar, in that advantage is taken of the inertia of the members to allow the generation of high forces acting between them.

This hydraulic system provides a simple rugged structure for accomplishing a stepwise movement between a punch carried in a head mechanism and the head mechanism itself. This mechanism, in cooperation with resilient means for driving the head mechanism, provides a structure capable of supplying a plurality of high intensity impacts to a material being compacted during each compression stroke of an ordinary crankoperated press. By providing such a series oi! high impacts, it is possible to secure much greater compaction of the material than could otherwise be achieved in a press of the same physical size.

Various modifications may be made in the elements of the press and hydraulic system to accommodate the structure for specific purposes without departing from the spirit and scope of the invention.

Having described the invention, I claim:

1. In a press, in combination, a punch for applying force to material to be compressed, a movable head, means capable of stepwise reduction in length for connecting the punch to the movable head, a force generating mechanism, and resilient means connecting the generating mechanism to the movable head, said resilient means cooperating with the connecting means interposed between the punch and head to produce stepwise movement of the head and the application of impact force to the punch at the termination of each step of the stepwise movement.

2. In a press, in combination, a punch for applying force to material to be compressed, a movable head, a hydraulic piston and cylinder for connecting the punch to the head, a force generating mechanism, resilient means connecting the force generating mechanism to the head, and means for intermittently permitting escape of fluid from the hydraulic cylinder to eifect stepwise movement of the head toward the punch and the application of an impact force to the material at the termination of each stepwise movement.

3. In a press, in combination, a punch for applying force to material to be compressed, a movable head, a hydraulic piston and cylinder for connecting the punch to the head, a member driven by a crank and connecting rod, resilient members connecting the driven member to the head, said resilient members being compressed by engagement of the punch with the material prior to the end of the stroke of the driven member, and means for permitting intermittent escape of fluid from the hydraulic cylinder to effect stepwise movement or the head while the punch is engaged with the material and the resilient members are compressed by the driven member.

wise movement of the head while the punch is engaged with the material and the resilient members are compressed by the driven member.

5. In combination with a press for applying impact forces to a material being compressed, a head, force generating mechanism for effecting a given stroke of said head, means for resiliently connecting said head to said force generating mechanism, a punch, a hydraulic valve and piston mounted on said head and connected to said punch, a fluid receiver, and means including a rotary valve for effecting stepwise movement of the head with respect to the punch by intermittently connecting the cylinder to a fluid receiver to allow intermittent escape of fluid from the cylinder during said given stroke.

6. In a device of the class described, in combination, a pair of members, means for resiliently urging the same relatively toward each other, a hydraulic cylinder and piston for separating said members, a force generating mechanism for efiecting a given stroke of said members, a metering piston and cylinder, resilient means urging the metering piston toward one end of its stroke, and valving mechanism for alternately connecting the metering cylinder to the hydraulic cylinder and to a pressure receiver to discharge a quantity of fluid from the hydraulic cylinder thus efiecting one step of a stepwise approach between said members during said given stroke for each operation of the valving mechanism.

7. In a device of the class described, in combination, a pair of members, means for resiliently urging the same relatively toward each other,

a hydraulic cylinder and piston for separating said members, a force generating mechanism for effecting a given stroke of said members, and mechanism for intermittently permitting the escape of metered quantities of fluid from the cylinder, said mechanism comprising a rotatable cylinder having spaced ports in its periphery, a metering piston slidable within the rotatable cylinder, a spring urging the metering piston toward that end of its stroke tending to eject fluid through the ports, a casing surrounding the rotatable cylinder, said casing having ports that register with the ports in the cylinder, one of said casing ports being connected to the hydraulic cylinder and another being connected to a fluid receiver, and said rotatable cylinder and metering piston serving to pass metered quantities of fluid from the hydraulic cylinder to efiect stepwise movement of the members toward each other during said given stroke.

CLARENCE C. ZKINKER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 605,169 Loretz June 7, 1898 651,502 Fitzgerald June 12, 1900 2,127,877 Maglott Aug. 23, 1938 2,169,280 Pfanstiehl Aug. 15, 1939 2,169,281 Pfanstiehl Aug. 15, 1939 2,198,612 Hardy Apr. 30, 1940 2,449,257 Tucker Sept. 14, 1948 2,482,280 Lerma Sept. 30, 1949

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