US3158048A

US3158048A - Impact machine

Info

Publication number: US3158048A
Application number: US64759A
Authority: US
Inventors: Leo C Bollar
Original assignee: Warner and Swasey Co
Current assignee: Warner and Swasey Co
Priority date: 1960-10-25
Filing date: 1960-10-25
Publication date: 1964-11-24
Anticipated expiration: 1981-11-24

Description

United States Patent 3,158,048 IMPACT MACHINE Leo C. Bollar, Pomona, Calif., assignor, by mesne assignments, to The Warner 8r Swasey Company, Cleveland, Uhio, a corporation of ()hio Filed Oct. 25, 1960, Ser. No. 64,759 6 Ciaims. (Cl. 78-42) This invention has to do with improvements in high energy impact machines of the general type comprising cylinder and piston or ram components individually connected to a pair of platens which, from spaced apart positions, are brought relatively together at high velocity and with great force by sudden exposure of an area of the piston or ram to high gas pressure. Typically, such machines are usable for the application of high magnitude forces to forging or extrusion dies carried by and between the platens.

One general object of the invention is to provide an improved machine of this type, characterized by its simplification of the basic platen, cylinder and ram combination, and significant efficiencies, performance levels and structural economies resulting from the simplification. In this respect, the invention reduces the principal components to a simple scalable association of the cylinder and ram adapted to function in a manner giving sudden exposure of the ram to the working or driving gas pres sure, and interconnections between the platens, cylinder and ram, that will withstand the impact forces without requiring expensive or massive structural parts having high replacement costs. I

Heretofore, various proposals have been made for maintaining between a cylinder and contained force transmitting part such as a column, piston or ram, and in one relative position thereof, an annular seal preventing access of actuating gas pressure to a working area of such force transmitting part, until the seal is suddenly broken to give instantaneous exposure of that area to the actuating gas pressure, thus to produce high energy forces bringing the platens relatively together.

The present invention contemplates a new seal structure and arrangement having outstanding advantages in several respects, among which are the capacity of the seal to function at different relative axial positions of the ram and cylinder, and to necessitate only a simple ram or cylinder arrangement whereby the working pressure area of the ram is receivable in the cylinder head sealed off from high pressure gas in the cylinder, and is removable therefrom to give sudden actuating exposure of the ram to the cylinder pressure. According to a preferred structure an end portion of the ram is received within and in sealing engagement with the wall of a bore in the cylinder head, and means is provided for displacing the ram out of the bore to give sudden exposure of the full cross sectional area of the ram.

Other features of the invention have to do with provisions for cushioning theplaten impact force by the incorporation of a cushion medium in the interconnection ice going, will be understood from the following detailed description of an illustrative embodiment of the invention shown by the accompanying drawings, in which:

FIG. 1 is an elevationalview, partly in section, showing the parts in position at the start of the impact stroke;

FIG. 2 is a similar view showing the platens brought together substantially to the point of die impact;

FIG. 3 is a reduced cross section on line 3-3 of FIG. 2; and

FIG. 4 is a fragmentary section showing the sealin association of the rain and cylinder head. 5

The machine may bedescribed generally as comprising upper and lower platens and 11 adapted to carry by' a suitable mode ofattachment, work-forming elements such as the die

blocks

12 and 13 adapted to receive within their cavities 14 and 15 work metal to be forged in conformity with the shape characteristics of the cavities. The platens are movable relatively together and at high impact velocity, from the FIG. 1 positions to the condition illustrated in FIG. 2, by the sudden development and application of high gas pressure within the ram and cylinder assembly generally indicated at 16.

The assembly 16 comprises a cylinder 17 having its lower end threaded at 18 or otherwise secured to a base 19, the upper end of the cylinder being enclosed by head 20 shown to be threaded at 21 into the cylinder and to contain an axially concentric bore 22. The cylinder contains a column or ram 23, the lower end of which is threaded at 24 into the platen It or otherwise detachably secured thereto by suitable means, so that the ram and platen move as a unit in'vertical travel. The ram extends through a bearing 25 in the cylinder base 19, suitable means such as seal rings 26 being provided to prevent fluid leakage from the cylinder downwardly past the bearing. I

The ram 23, annularly spaced from the cylinder t provide a high pressure gas chamber 27, has an enlarged diameter upper end portion 28 which is receivable within bore 22 in the FIG. 1 position of the parts. The peripheral surface of the enlargement 28 and the receiving bore 22 are formed cylindrically and with substantially sliding tolerance. A seal ring 29, in the form of a Teflon or equivalently serviceable O-ring, is interposed between the ram and bore wall, preferably by accommodating the H O-ring in an annular recess 30 in the cylinder head 2%,

to form a fluid tight seal between the cylinder head and the received ram end. As shown in FIG. 4, the end of the ram surface may be beveled as illustrated to assure of one of the platens with the ram-cylinder component movable therewith. According to a preferred arrangeent, such interconnection comprises tubular piston assemblies working within bores in the platen to be moved thereby, and acting to displace the platen through confined pressurized gas which, beyond the point of the platen impact, is compressible to cushion the shock forces. In this manner it is made possible to reduce the bulk and cost of the force-transmitting tubular rods, in comparison with more conventional concepts of undertaking to match the strength of force transmitting members with shock forces to be assumed.

The invention has various additional features and objects, all of which as well as those outlined in the foresmooth entry into the seal ring. It is to be particularly noted that the seal remains effective when the O-ring is engaged by any axial extent of the ram surface within the bore, and therefore, being effective at different relative axial positions of the cylinder head and contained ram end, is not dependent upon arrival or maintenance of-the ram and cylinder at any single or precise relative axial position. Thus, with the ram received within the cylinder head, any space at 30 is sealed against leakage of high pressure fluid delivered thereto through line 31, until the ram is displaced out of the head bore, all as will later appear.

The cylinder base 19 is connected to the platen 11 in a manner permitting simultaneous upward displacement of the platenand cylinder, and further travel of the cylinder beyond the point of die impact, by the tubular plunger or piston assembly as generally indicated at 32. Each of these assemblies comprises a tube 33 slidable through bearing 34 in the platen 10 and removably retained within the cylinder base 19 by bushing 35 threaded into the upper end of the tube which enters the tube-receiving bore 36 and bears downwardly against the base 19. The tube extends downwardly through sealed bearing 37 in the platen 11 into counterbore 38 forming a gas chamberto 3 which surface 39 of the plunger or piston head 40 threaded into the lower end of the rod, is exposed. Enlarged diameter bore 41 below bore 38 contains a floating piston 42, the uppermost position of which is determined by its engagement with shoulder 43. Chamber 44 between piston 42 and plug 45 in the lower end of bore 41, communicates with chamber 46 by way of passage 47.

High gas pressure derived from a suitable source such as accumulator 48, is communicated to the cylinder chamber 27 by way of line 49 and passage 50 in the cylinder head, and to chamber 46 through line 51, passage 52 in the bushing 35, the interior of tube 33 and port 53. The pressure thus communicated to chamber 46 is transmitted through passage 47 to chamber 44 and the underside of floating piston 42, the pressure differential corresponding to the difference of the exposed

piston areas

39 and 54, acting to position the parts as shown in FIG. 1. An independently pressurized fluid, such as oil, may be delivered between pistons 40 and 42 at the interface 55, by way of tube 56 the lower end of which is received at 57 within passage 58 in the piston 40, the upper end of the tube being secured at 59 within passage 60 in the bushing 35, to which the pressurized oil is delivered through line 61.

Cylinder 17 contains a floating piston 62 carrying seal rings engaging the cylinder wall and ram surface, and containing a counter-bore 63 adapted to receive the ram head enlargement 28, as illustrated in FIG. 2. The floating piston 62 is displaceable upwardly within the cylinder by pressurized oil delivered beneath the piston through passage 64 by way of line 65.

Suitable provision may be made for ejecting the forged object from die 13, automatically in response to return travel of the platen 11 from the FIG. 2 to the FIG. 1 positions. Such means, generally indicated at 165, may comprise a cylinder 66 slidably contained within the platen bore 67, the bottom of the cylinder containing a plug 68 having a passage 69 through which pressurized gas is supplied to the cylinder through line 70. The cylinder is secured at 71 to a base plate 72, which in turn may be attached stationarily to a floor, not shown. Cylinder 66 contains a fixed head 73, the rod 74 of which extends upwardly into the platen bore 75. The rod carries a seal ring 76 and contains a passage 77 through which the gas pressure within the cylinder is communicated about the rod below the seal 76 and to space 78 above the head, such communication occurring even though the rod may have but a slight clearance within the bore 75. The die 13 is shown to contain an ejector having a head 80 receivable downwardly within the recess 81, and a pin 82 extending down through the die into bore 75.

In considering the operation of the machine, accumulator 48 and the communicating chamber 47 are charged with gas at high pressure, say in the order of 2000 psi, and at the cycle start, the parts may be positioned as in FIG. 1. Gas is introduced through line 31 to the sealed space 30 under pressure sufiicient to overcome the resistance to displacement of the ram out of bore 22, as imposed mainly by the gas pressure in chamber 27 exerted against annular area 83 of the ram. The communication of pressure to space 30 displaces the cylinder 17 and ram 23 relatively apart, in effect withdrawing the ram head 28 from the cylinder head bore, in a manner such that the effective cross sectional area of the ram is suddenly exposed to the gas pressure in chamber 29. It will be noted that such pressure communication to the end of the ram occurs without any restriction, 'by reason of the ram end being openingly exposed within chamber 27. In this manner, the ram receives the maximum energy obtainable from a body of compressed gas.

Upon such exposure of the ram, the pressure in chamber 27 acts to displace the ram, platen and the die 12, downwardly at extremely high velocity, and simultaneously to elevate cylinder 17 =and'the lower platen 11 through the tubular connectors 32, so that ultimately the die blocks are brought together as in the FIG. 2 condition. Due to the pressure of the gas in chamber 46, the rod 33 and piston 40 may not depart in advance of the die impact, appreciably from the FIG. 1 position relative to platen 11. However, upon the die impact, the rod and piston are displaceable upwardly within chamber 38, instantaneously compressing the gas therein to cushion the impact. During such cushioning travel, the piston 40 moves upwardly away from the floating piston 42. On the down stroke of the piston, occurring as the assembly may oscillate to equilibrium, piston 40 may displace the floating piston downwardly, and such displacement is cushioned by compression of the gas in chamber 44. In a short interval, the oscillations dampen out and the parts tend to restore to the FIG. 1 position. For balanced performance of the assembly, it is found desirable to size the piston areas 84 exposed to the pressure in chambers 46, each at one-half the cross sectional area of the intermediate or body portion of the ram 23.

The cushioning effect of the gas in chamber 44 against impaction of piston 40 downwardly against the floating piston 42, may be controllably varied by the introduction of oil from line 61 through tube 56 at the piston interface 55, to lift the piston 40 and rod 33 above the position shown, thereby decreasing the gas volume in chamber 44. This method of elevating the rods may also be used to vary the spacing between the platens and die blocks. An additional effect of the oil so introduced is to afford a more even distribution of impact forces transmitted from one to the pistons.

To restore the parts from the FIG. 2 condition to the cycle starting positions of FIG. 1, pressurized oil is introduced through line 65 beneath the floating piston 62, displacing the latter upwardly to engage the ram head 28 as in FIG. 2, and elevating the ram into sealing condition within the cylinder head bore 22, it being understood that the oil pressure will be sutficiently high to overcome the gas pressure in chamber 27 and accumulator 48 during the restoration. As will be understood, the pressure in space 30 will be released to allow entry of the ram end to sealed position. When the oil pressure in line 65 is released, the gas pressure in chamber 27 returns the piston 62 to its bottom position.

Concerning the ejector mechanism, the object to be forged is placed upon the ejector head in its elevated position shown in FIG. 1, as maintained by engagement with the rod 74. As the parts move toward impact, platen 11 is elevated relative to cylinder 66 and the piston 73, allowing the ejector to settle into the die block recess 81. Following impact, the lowering movement of platen 11, cushioned by compression of the gas in chamber 78, brings pin 82 downwardly against the rod 74 and eifects work ejecting restoration of the head 80 and die 13 to the FIG. 1 position.

I claim:

1. A high energy sudden impact machine comprising a pair of vertically spaced upper and lower platens both vertically movable, a cylinder above the upper platen and connected to the lower platen to be vertically movable therewith, a ram contained in the cylinder and connected to the upper platen so that opposite relative axial movements of the cylinder and ram move the platens relatively toward and away from each other, said cylinder including a head containing a bore which receives and has sealing engagement with a peripheral surface of the upper end of the ram, means for introducing high pressure gas to the cylinder, means operable to displace said ram, said ram having open annular spacing from the cylinder throughout the extent of the ram travel therein to provide a compressed gas chamber, means for supplying compressedgas to said chamber, and an annular piston in said chamber about the ram and operable to elevate the ram into said cylinder head bore.

2. A machine according to claim 1, including also means for vertically adjusting the cylinder relative to the lower platen to vary the platen spacing and their impact force when brought together.

3. A machine according to claim 2, including also yielding means for cushioning relative vertical movement of the cylinder and lower platen at their impacting positions.

4. A high energy impact machine comprising a pair of vertically spaced vertically movable upper and lower platens, a vertically movable cylinder, means connecting the cylinder to the lower platen and a ram contained in the cylinder and connected to the upper platen so that opposite movements of the cylinder and ram move the platens toward and away fom each other, means to suddenly applying high gas pressure to the ram to produce high velocity movement together of the platens to arrested impact positions, the first mentioned means comprising rods interconnecting the cylinder and said lower platen in balanced relation at opposite sides of the ram and carrying pistons displaceable against compressed gas to cause the lower platen to move vertically with the cylinder as the platens travel together, said rods and cylinder being movable past said platen impact positions by cushioning compression of said gas by the pistons, said rods being tubular and gas pressure being applied to the pistons through the rods.

5. A machine according to claim 4, in which said rods extend downwardly into cylinder bores in said lower platen, said bores containing floating pistons below the first mentioned pistons, and means for selectively delivering compressed gas and pressurized liquid through said rods to said bores respectively above the first mentioned pistons and between the latter and said floating pistons.

6. A machine according to claim 5, in which said rods contain tubes through which said pressurized liquid is delivered to said bores between the first mentioned and floating pistons.

References Cited in the file of this patent UNITED STATES PATENTS 1,315,010 Culhane Sept. 2, 1919 1,633,970 Ball June 28, 1927 1,893,187 Urbanek Jan. 3,193 2,122,899 Towler July 5, 1938 2,363,142 Reed Nov. 21, 1944 2,384,163 Flowers Sept. 4, 1945 2,648,949 Taylor Aug. 18, 1953 2,931,218 Ottestad Apr. 5, 1960 2,932,951 I Ottestad Apr. 19, 1960 2,959,049 Luttrell Nov. 8, 1960 2,960,067 Osborne Nov. 15, 1960 3,036,538

Ottestad May 29, 1962

Claims

1. A HIGH ENERGY SUDDEN IMPACT MACHINE COMPRISING A PAIR OF VERTICALLY SPACED UPPER AND LOWER PLATENS BOTH VERTICALLY MOVABLE, A CYLINDER ABOVE THE UPPER PLATEN AND CONNECTED TO THE LOWER PLATEN TO BE VERTICALLY MOVABLE THEREWITH, A RAM CONTAINED IN THE CYLINDER AND CONNECTED TO THE UPPER PLATEN SO THAT OPPOSITE RELATIVE AXIAL MOVEMENTS OF THE CYLINDER AND RAM MOVE THE PLATENS RELATIVELY TOWARD AND AWAY FROM EACH OTHER, SAID CYLINDER INCLUDING A HEAD CONTAINING A BORE WHICH RECEIVES AND HAS SEALING ENGAGEMENT WITH A PERIPHERAL SURFACE OF THE UPPER END OF THE RAM, MEANS FOR INTRODUCING HIGH PRESSURE GAS TO THE CYLINDER, MEANS OPERABLE TO DISPLACE SAID RAM, SAID RAM HAVING OPEN ANNULAR SPACING FROM THE CYLINDER THROUGHOUT THE EXTENT OF THE RAM TRAVEL THEREIN TO PROVIDE A COMPRESSED GAS CHAMBER, MEANS FOR SUPPLYING COMPRESSED GAS TO SAID CHAMBER, AND AN ANNULAR PISTON IN SAID CHAMBER ABOUT THE RAM AND OPERABLE TO ELEVATE THE RAM INTO SAID CYLINDER HEAD BORE.