US2730981A - Press platen stop block - Google Patents

Description

Jan. 17, 1956 w. ERNST PRESS PLATEN STOP BLOCK 5 Sheets-Sheet 1 Original Filed Sept. 15, 1949 FIG-I INVENTOR WALT'ER ERNST g z 5 ATTORNEYS.

Jan. 17, 1956 w. ERNST 3 PRESS PLATEN STOP BLOCK Original Filed Sept. 15, 1949 5 Sheets-Sheet 2 mven'ron WALTER ERNST 8Y7 .cyaf

ATTORNEYS Jan. 17, 1956 w. ERNST 2,730,931

PRESS PLATEN STOP BLOCK Original Filed Sept. 15, 1949 5 Sheets-Sheet 4 1 l4 2 's y &\\\ &\K

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Jan. 17, 1956 w. ERNST 2,730,981

PRESS PLATEN STOP BLOCK Original Filed Sept. 15, 1949 5 Sheets-Sheet 5 I a 4 A76 LTER 23:51

///I Mia/ MW 154 ATTORNEYS.

VII /IIIIIIIIIII" United States Patent PRESS PLATEN STOP BLOCK Walter Ernst, Day ton, Ohio, assignor to The Commonwealth Engineering Company of Ohio, Dayton, Ohio, a corporation of Ohio 2 Claims. (Cl. 113-45) This invention relates to presses, especially to hydraulic presses,.and particularly to the frame structure thereof, and 1s a d1v1sion of my copending application Serial Number 115,901, filed September 15, 1949, now Patent No. 2,672,836, issued March 23, 1954.

In the manufacture of presses as generally practiced at the present time, each press is constructed to 0perate at a particular tonnage and in a particular fashion.

That is to say, a five hundred ton press can be operated on any jobs up to five hundred tons, but will not carry out work above that tonnage, and the press can operate as a blankholder press, it it is equipped with a blankholder, but cannot handle work of that nature unless the blankholder is built into the press at the time of manufacture thereof.

This condition has existed because it has been customary to design and construct each press according to the requirements of a single job or a single type of work. Formerly, this practice did not represent any substantial lack of economy because there were less rapid changes in types of jobs and of styles of product than there are in present-day products.

In modern production, for a machine tool to be utilized to its fullest value, it must be sufliciently versatile to handle a number of different types of work operations and to be convertible from one type job to another relatively quickly and inexpensively.

Further, in the modern competitive field, machine tools must be produced economically and sold at the lowest possible price in order to be salable against other similar products.

7 methods.

a In particular it is an object of this invention to provide a hydraulic press structure which is highly versatile and -can readilybe adapted for a number of different types of work operations.

Another particular object of this invention is to provide a press structure which is convenient to manufacture and which, accordingly,-is an economical press to manufacture. It is also an object to provide an improved guiding means for the platen of the press which is better able -to withstand deflecting loads on the press, platen and which is easy to construct and install in the press.

These and other objects and advantages will become more apparent upon reference to the following description taken. in connection with the accompanying drawings, in which;

Figure l. is a front elevational view of a press constructed according to my invention;

Figure 2 is a vertical section through the upper part of the press on substantially the center line thereof and f'ls l nl h ausd s i Pi 1;

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Figure 3 is a sectional view of the lower part of the press taken along the lines 33 of Figure 5;

Figure 4 is a plan section through the press platen and frame and is indicated by line 4-4 on Figure 2;

Figure 5 is a plan section through the lower part of the press and is indicated by line 55 on Figure 3;

Figure 6 is still another plan section through the press at the level of the blankholder platen and isindicated by line 66 on Figure 3;

Figure 7 is an enlarged view taken through one corner of the press platen and the adjacent corner of the press frame showing the gib guiding arrangement for the platen according to this invention; and

Figure 8 is a view similar to Figure 7 but showing the guiding arrangement for the blankholder platen.

Referring to the drawings somewhat more in detail, a. press constructed in accordance with this invention comprises a bed ill and a head 12 spaced apart by the uprights l4. Extending through uprights 14 are strain rods 16 connected to the ends of which are the nuts 18 by means of which the head, bed, and uprights are clamped together.

The strain rods 16 serve as keys for holding the head, bed, and uprights in aligned relation by virtueof the enlarged diameter portions 29 on the rods which closely fit within machined bores in the head, bed, and uprigh where these members abut.

According to the present invention, the press head and the cylinder therein are separate castings. This is a preferred practice because the cylinder can be of the exact size required to do the work which is to be placed in the press, and full advantage taken of the available hydraulic horsepower.

This arrangement also permits exchange of the cylinder for one of a dilferent size to meet varying work conditions. Also, the cylinder castings are easier to produce because the combinationof thick and thin sections is avoided and the amount of scrap due to leaky cylinder castings is substantially less than would obtain if the cylinder were integral with the press head.

In Figure 2 it will be seen that the press head has a central bore 22 having smoothly machined annular areas 7 24 at its upper and lower ends. Within bore 22 is cylinder casting 26 having machined annular areas thatengage the areas 24 within the bore 22 and thus hold the cylinder in exact alignment in the press head, Cylinder 26 has a relatively large flange 30 thereon below the press head, and bolts 32 extend through this flange into the head for retaining the cylinder and head assembled.

The press head supports a tank arrangement 34 into which the upper end of cylinder 26 extends, and there is provided packing 36 about the upper end of the cylinder adapted for being compressed by a gland 38 to prevent leakage. of fluid from the tank around the cylinder.

' Reciprocably mounted in cylinder 26 is the double acting press ram 49 that extends out through the bottom of the cylinder through packing 42 for connection with the press platen 44, as by the split ring 46.

' Ram 40 may also be axially bored from its upper end,

as at 47, for receiving the auxiliary plunger 48 that is preferably hollow, as at 49, to permit fluid to be supplied to the lower end of bore 4-7.

Fluid is adapted for being supplied to the upper end of the press cylinder by a conduit 56 that communicates with a passage 51 in the upper end of the press cylinder. In the arrangement shown, passage 46 communicates with municates with the inlet of a pressure shiftover valve 52 which is preferably mounted on the side of the upper end of cylinder 26.

r The press head is provided with a plurality of spaced bores 53 in which are mounted surge valves 54. The surge plunger is moving upwardly.

:formed in its corners.

also adapted for being piloted open by pressure supplied thereto through the conduit means 56 when the press There is preferably one surge valve associated with the aum'liary plunger 48, while there are two surge valves associated with the cylinder 26.

Fluid connection is had with the lower side of plunger 40 by conduit 64 which communicates with a passage 66 formed in flange 39 at the lower end of cylinder 26.

It may be noted at this time that the conduits 50 and 64 are permanentlyaflixed in the press head as by welding,

' so that the removingof the press cylinder or the placing of it in the press is a relatively simple matter and involves a minimum of pipe connections. For example, at the upper end of the cylinder asmall elbow fitting 68 may be employed for making connection between conduit 50 and the press cylinder, while at the lower end of the press cylinder the O-ring 70 provides the means for effecting connection between conduit 64 and passage 66.

Turning now to the press platen, the construction of this member will best be seen in Figures 2, 4, and 7. The

platen comprises a cast member having ledges 72 formed in its front and back faces and also having the notches 74 The notches 74 are for the purpose of adjustably receiving the gib members 76. These members 76 are L-shaped with the end of the leg at the side of the platen bevelled off,,as at 78 to bear against the press guides 80. i

Gib members 76 are'clamped tightly against a machined surface on the side of the platen by bolts 82 which extend through clearance holes in the corners of the platen.

. The gib members 76 are adjustable toward and away from the guides StP-by means of the set screws 84 extending through the gib members from the front and bearing against one face of the notches 74, and the bolts 86 extending through the gib members and into the said platen.

'It will be apparent that the combination of the bolts 82, the abutment screws 84, and the clamp screws 86 provides a ready means for positively determining the location of the gib members 76 on the platen. It will also be noted that there are substantially no twisting forces exerted on any of the said locating means for the gib members, or on the gib members themselves, but that any thrusts that are imposed on the said gib members due to impending deflections of the platen are carried by the gib members or the fastening means therefor purely in tension or compression.

It may be pointed out at this time that the guides 80 are mounted on the uprights of the press by means of the .tongue and groove arrangement which will be best seen at 88 in Figure 7. The groove in the upright canreadily be formed by simple machining processes, and the tongue on the guide can also be formed thereon in a very simple manner.

The guides are preferably of hardened steel, surface ground, and may either be manufactured or purchased commercially at a reasonable cost. The grooves run the full length of the upright, but the guides'are cut off, as

indicated at 87 in Figure 3, the correct length to give any required daylight and stroke combination. there is no pattern change or redesigning of the press necessary in changing the stroke-daylight relationship. Bolts 90 may be distributed along the guides for clamping them tightly in position against their associated uprights.

It will be noted in Figures 2 and 4'that the platen 44 has extensions 92 thereon extending into the space between the guides 80. These extensions are utilized for providing a positive stop for the platen by locating the stop blocks 94 on the bed in the space between the guides.

The platen is designed to sustain the full tonnageof the press, and the stop blocks 94 and projections 92 on the platen thus represent an inexpensive and effective arrangement for providing a positive stop for the platen and ram.

As will be particularly observed in Figure 5, the uprights 14 have through openings 94A therein immediately above the bed 10 of the press and in alignment with the stop blocks 94. These openings are normally closed by cover plates 96, but, if it should be desired to operate the press with a transverse through opening for feeding strip stock or the like therethrough, the said cover plates the surface of the bed when the blankholder motor is in its lowermost position. It'will also be noted in Figure 3 that if'the stop blocks 94 are removed, the press platen can readily be disassembled from the press by dropping it down below the lower ends of the guidesand then sliding it laterally out of the press through either the front or back opening thereof. The press bed, best seen in Figures 3 and 5, is a cast member similar to the head and includes a substantially rectangular central opening 98 which may be utilized for the purpose of receiving a die cushion or ejector unit. a

For detachably receiving the die cushion or ejector assembly, the press bed has the upstanding bored bosses 100 through which the strain rods 7102 can be passed for supporting the beams 104 that extend from the front to the back of the press and on .the underneath side of the bed. These beams are adapted for receiving the projecting parts 106 of the die cushion or ejector cylinder 108 which reciprocably receives a plunger 110 on the upper end of which is mounted a platen 112.

Platen 112 is adapted for being guided in its reciproca tory movements by the guide rails 114 mounted on the faces of ribs about the cavity 98.

It will be understood that usually there is a bolster plate resting on the upper surface. of the press bed and that the platen 112 will normally bottom against the underneath side of the said bolster plate. In the manufacture of the press, the press bed is always formed with the rectangular opening 98 extending therethrough and with the upstanding bored bosses 100, so that at any time it is desired to do so, the die cushion or ejector assembly can be mounted in the press or removed therefrom. The illustrated arrangement permits this to be done in a minimum of time and at a minimum pf expense.

In many instances it is necessary to supply a press of the type illustrated with a blankholder arrangement for holding a blank during a drawing operation. The blankholder a gem t comprises a blankhol e p aten positioned beneath ,the main platen 44 and suspended therefrom by the pick-up rods 152 which pass loosely through bored holes in the ledges at the front and back faces of the main platen. Platen 150 has a, central opening 151 to admit a punch or the like to be carried by the main platen for action on the center part of a blank, the periphery of which is to be engaged by the blankholder platen. V

The blankholder platen is generally stationary while i it is working and therefore does not require the heavy gib arrangement already described in connection with the main platen. Rather; the blankholder platen is so shaped as to extend along the diagonal faces of the guides V 80 and engagement of the blankholder platen with the said guides is accomplished by means of the relatively .thin wear plates 154 bolted on the diagonal faces of the inders and pistons detachably mounted in the press bed and having upwardly extending rods connected with the blankholder platen so as to pull it downwardly with the proper amount of force.

The blankholder actuating arrangement is best seen in Figure 3, wherein it will be seen that the press bed has a cavity on each side thereof opening upwardly from the bottom, as at 156, for receiving one of the two blankholder actuating cylinders S. Reciprocable in each cylinder 158 is a double acting piston 160 having rod members of equal diameters extending from its opposite faces, as at 162 and 164. The lower of the rods 164 each have connected therewith a yoke member 166 extending from the front to the back of the press.

At each end of each of the yokes 166 there are connected the vertically extending pull down rods 168 which extend through suitable bores 170 in the press bed into engagement with the blankholder platen 150. Nuts 172 may comprise the means for tightly clamping the rods to the yokes 166 and to the blankholder platen. This is desirable in order to give the proper distribution of force over the blankholder platen and also regulate the blank holder pressure at the several corners, should it be so desired.

The rods 168 are adapted for being stopped in a predetermined downward position by adjustable sleeves 176 thereon which pass through bushings 176 at the top of the bed 10, and have heads 178 thereon at their lower ends which fit relatively closely in bores 170. The sleeves 176 are adjustable on rods 168 by being threaded thereto, as at 180, and are adapted for abutting the caps 182 secured to the bed at the lower ends of the bores 176.

As will be seen hereinafter, when the blankholder 150 is in its actuated position, the sleeves 174 all bottom against caps 182 and adjustment of the sleeves on the rods is effective for regulating the action of the blankholder platen at its respective corners.

According to this invention, the actuation of the blankholder platen by means of the pistons 160 is accomplished by the supplying of a minimum amount of finid to the said pistons. This is due in part to the fact that tr e opposite faces of pistons 160 are equal in area, and in part to the fact that the blankholder moves to its Working position before any pressure is applied, and then dwells there stationarily under pressure, as contrasted to blankholder arrangements of the prior art where either the blankholder its actuating plunger, or the cylinder for the said plunger are in movement during the supplying of pressure thereto, thus entailing a considerable expenditure of power, which is eliminated with the instant invention.

The blankholder pistons 100 each comprise a central bore 184 that reciprocably receives a valve piston 186, The bore 184 comprises the spaced grooves 183 and 199 with the groove 1S3 communicating by passage means 192 with the space in cylinder 158 below the piston and the groove 1% communicating by passage means 194 with the space in cylinder 158 above piston 16!].

Piston 186 is normally urged downwardly by compression spring 196 bearing between the said piston and the lower end of rod 162. In this position the piston affords free communication between the opposite ends of cylinder 158, so that the piston 160 and its rods 162 and 164 can reciprocate freely in cylinder 158 without any fluid being displaced therefrom or supplied thereto.

The lower rods 164 have passages 198 therethrough that communicate with flexible conduits 200 through which pressure is supplied to the cylinders to actuate the blankholder.

In operation, after the blankholder platen is in working position, pressure is supplied to the upper end of cylinder 158 through conduit 200, bore 198, and passage 194 and acts downwardly on piston 160 and urges the blankholder platen downwardly toward the blank which is therebeneath. As has been mentioned before, when the blankholder is in workingposition, sleeves 176 bottom against caps 182, and it will now be seen that the individual pressures in the several corners of the blankholder platen can be independently adjustedby adjust:- ment of the sleeves 174. It will also be seen that a minimum of fluid under pressure is required for obtaining the blankholder action, due to the fact that the blankholder platen and its actuating pistons are in working position before pressure is supplied to the said pistons.

It will be observed that the entire blankholder arrangement can readily be installed in a press constructed according to this invention, or, if already assembled with the press, can readily be removed therefrom. No change in the press design is required to add the blankholder, and it is only necessary to supply the requisite parts and to assemble them in proper relation with the other parts of the press. It might be noted that the cylinders 158 are flanged, as at 218, at their lower ends, so that the working thrust exerted on the blankholder is carried on the underneath surface of the bed and acts upwardly thereon.

In removing the blankholder assembly, the rods 168 are disconnected from platen and then, after the caps 132 are removed and the cylinders 158 unbolted from the bed, and the hydraulic connections opened, the entire blankholder assembly can be lowered into the pit beneath the press. Thereafter, the platen 150 is disconnected from the main platen and removed from the press frame.

It is to be noted that the blankholder imposes no load whatsoever on the press frame except a certain amount of compression loading on the press bed, and which loading in no way influences the design of the press frame. Thus, if a three hundred ton press were to be constructed and with a press frame to carry the three hundred tons load, it would not be necessary to redesign the press frame in order to associate with it a blankholder arrangement with a rating, say, of one hundred tons.

It will be evident that this is of distinct advantage in giving the press a great deal more utility, in making it more inexpensive to construct, and in permitting a press user to convert it readily from one type of operation to another.

The die cushion structure previously described can be arranged to operate on any particular sort of cycle desired, as more fully disclosed in my copending application Serial Number 115,901. The die cushion is removable from the press in its entirety so that the press can be purchased with or without the die cushion, or the die cushion can be added to a press or removed therefrom at any time desired in order to adapt it to particular working conditions. Similarly as with the blankholder assembly, the die cushion is removed by unbolting it from the press bed, opening the hydraulic lines thereto, and lowering into the pit beneath the press.

It will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions, and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

I claim:

1. In a press; a bed, a head, spaced upright members extending between said head and bed, spaced guide rails carried on each upright and extending into the space between the uprights, a press platen between said uprights and having gib means engaging said guide rails, a blankholder platen supported beneath said press platen, said blankholder platen having gib means to slidably engage said guide rails, vertical reciprocable piston means in said bed, means connecting said piston means with said blankholder platen, a rod extending upwardly from said piston between said guide rails, a stop block on said bed, said rod terminating at substantially the upper edge .of the stop, block when said blankholder platen is in a raised position, said stop block having a passage therethrough ,to slidably receive said rod, and an integral projection on said press platen extending into the space between said guide rails for engagement with said stop block. a

2. In' a press as claimed in claim 1, with said stop block being removably secured to the inner face of one of said uprights.

References Cited in the file of this patent UNITED STATES PATENTS Parish Sept. 5, 1911'

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