US3302556A

US3302556A - Press frame

Info

Publication number: US3302556A
Application number: US457378A
Authority: US
Inventors: Stanley H Durbin
Original assignee: EW Bliss Co Inc
Current assignee: EW Bliss Co Inc
Priority date: 1965-05-20
Filing date: 1965-05-20
Publication date: 1967-02-07
Anticipated expiration: 1984-02-07
Also published as: GB1139189A; DE1577159A1

Description

S. H. DURBIN Feb. 7, 1967 PRESS FRAME 2 Sheets-Sheet 1 Filed May 20, 1965 FIG. 3

m mu

INVENTQR. STANLEY H. DURBIN 746m; 6? Bank;

ATTORNEYS Feb. 7, 1967 Filed May 20, 1965 s. H. DURBN 3,302,556

PRESS FRAME 2 Sheets-Sheet 2 0 FIG. 6

FIG. 4 1

24 Hi 1' 29 w r|6 H 22\ r5 x I I 1 27 I8 D INVENTOR. STANLEY H. DURBIN BY 7M 8 8044 ATTORNEYS FIG. 5

(PRlOR ART) United States Patent 3,302,556 PRESS FRAME Stanley H. Durbin, Canton, Ohio, assignor to E. W. Bliss Company, Canton, Ohio, a corporation of Delaware Filed May 20, 1965, Ser. No. 457,378 3 Claims. (Cl. 100-214) This invention pertains to the art of power presses and more particularly to a press having an improved crown arrangement.

The invention will be described with particular reference to a crown for a four column, underdriven, single action press of the type adapted to work where a steady pressure of known intensity must be exerted, such as coining, sizing, embossing and work requiring a dwell time, however it should be understood that it has much broader applications and may also be used on double action or general purpose presses and on presses where the slide of the press acts downwardly.

Conventional column presses include a bed and crown restrained by four columns. In underdriven presses, a reciprocal platen is carried by a bolster and acts against a fixed platen carried by the crown. The crown is usually a box member having column bosses at the corners. The columns are provided with shoulders upon which the crown rests, and nuts are prestressed on the ends of the columns projecting above the crown to hold it in place. Since the corners of the crown are held fixed and the press load is applied at the center, the box shaped crown has a tendency to bow from underneath. Though this distortion is very slight, it causes the columns to bend inwardly a measurable amount. Experience has shown that where rigid work specifications are imposed, deflections such as these are particularly detrimental.

The present invention contemplates a new and improved crown arrangement which will overcome this and other difficulties by distributing the loading forces to the columns equally and in an axial manner so as to avoid appreciable platen surface deflection.

In accordance with the invention there is provided a crown restrained by a plurality of columns and comprising a platen having a die supporting surface extending normal to the press axis, a plurality of truss members each having a column boss at the upper end and connected to the platen at the lower end, and tension bars extending laterally between each column boss whereby loading forces on the plate are absorbed equally by the truss members and transmitted axially to the columns without causing appreciable surface deflection to the platen.

Further in accordance with the invention where the invention is employed with a four column press, each truss member extends diagonally downwardly and inwardly to join with the platen adjacent the center thereof.

The principal object of the invention is to provide a crown for a column press which will transfer platen load equally to the columns without appreciable platen surface deflection.

Another object is to provide a crown comprised of a plurality of truss members each of which is arranged with respect to the platen so as to be in compression when distributing loads to the columns.

Still another object is to provide a crown as referred to above which will absorb lateral force components to prevent objectional column bending.

These and other objects will be appreciated more fully by referring to the following description and drawings wherein:

FIGURE 1 is a side elevational view of the four column press incorporating the invention;

FIGURE 2 is a plan view of a preferred embodiment of the invention taken along line 22 of FIGURE 1;

FIGURE 3 is a side elevational view offset along line 3-3 of FIGURE 2, to show a portion of the invention in vertical section;

FIGURE 4 is a fragmentary vertical sectional view taken along line 44 of FIGURE 2.

FIGURE 5 is an exaggerated schematic view dynamic'ally representing the column loading forces and the effect thereof on a conventional four column press;

FIGURE 6 is a dynamic representation of the invention showing in exaggerated form elastic deflection of the truss members and the forces at the columns under loading conditions; and

FIGURE 7 is a schematic plan view of the invention as shown in FIGURE 6 illustrating the laterally acting force components at the columns.

Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting same, FIGURE 1 shows in more or less schematic form a conventional underdriven four column press A having a bed B and a crown C restrained by four columns D. The bed B is supported in a pit E below the floor line F and reciprocally carries a slide G guided at the corners by the columns D. A fixed platen H is vertically spaced from the bed B by the crown C. The slide G is adapted to carry the lower half I of a die set while the platen H is arranged to carry the upper half I in fixed relationship to the slide G.

Referring now to FIGURES 2-4, the crown C and the platen H are preferably a single casting, the crown C comprising column bosses 16 each having an inner bore 18 adapted to fit over the reduced diameter portion 20 of each column D. The crown C rests in engagement with shoulders 22 on each column D as shown in FIG- URE 1 when it is assembled to the press time. Column nuts 24 are threaded on the column ends which project above the bosses 18 tightening the crown down against the shoulders 22. The portions 20 of the columns D may be prestressed in any well known manner such as by heating locally and then applying the nuts 24 before cooling. The crown C also includes a plurality of trusses 27, each cast as integral members of column bosses 16 and the platen H. Each truss 27 extends diagonally from the associated column boss 16 toward the center of the platen H forming a cross head 28 at the press axis as best seen in FIGURE 2. In addition, tension bars 29 are cast integrally between each column boss 16 to form a bail or box frame. These parts and arrangement of parts are mutually interrelated to have unique properties under load as will be more fully explained hereinafter.

Conventional column press construction, as depicted in FIGURE 5, is to provide a box like crown C with the col-umns D fastened at each corner. Under pressure, there is a tendency for the crown C' and the bed B to bow thus placing lateral bending forces on the ends of the columns, as denoted by the laterally directed force vector arrows shown. The forces are such that the columns are caused to sway inwardly at the middle. The extent of bending is small but the bowed condition of the crown C and bed B at high loads is of suflicient magnitude to be of concern since the press is unable to supply the accuracy needed in precision press work.

In accordance With the present invention, when a load is applied to the platen H, there will be no appreciable surface deflection and the lower surface 32 will remain parallel to the slide G though a certain amount of axial movement is permitted as exaggeratedly depicted in FIG- URE 6. Under dynamic loading condition, the truss members 27 equally distribute the loading forces on the platen H to the column bosses 16 and in such a manner that each column D receives an axial component and lateral components of the load as denoted by the vector arrows in FIGURE 6. The axial force components act vertically through the column nuts 24 and are taken directly in tension by the columns .D and transmitted to the bed B while the lateral force components act in opposition to one another and are absorbed by the tension bars 29. Thus the crown C isolates the columns from objectionable bending forces which would otherwise produce distortions of the type shown in FIGURE 5. More importantly, the truss arrangement imposes condition of symmetrical support necessary to insure that no appreciable platen surface deflection occurs.

It should also be noted that the trusses 27 act as flexural beams to a certain extent. That is, since each truss member 27 extends diagonally at an angle of about 4'5 degrees to the press axis, bending forces on them will act in such a manner as to cause a slight deformation as dynamically illustrated in FIGURE 6 in exaggerated form. The bending in each truss 27 is uniform however due to the symmetry of the spider-like truss arrangement and insures that the platen H 'will deflect axially without bending or tilting. This result is not appreciably affected by slightly off center loads.

Having thus described and illustrated a preferred embodiment of the invention, it will be understood that certain obvious modifications could be made by those skilled in the art without departing from the spirit of the invention as defined by the appended claims.

Having thus described my invention, I claim:

1. A four column press including a bed restrained at the ends of four columns extending therefrom and a pair of platens supported in relation to the bed such that one is fixed and the other is reciprocal relative thereto, said fixed platen being positioned symmetrically with respect to the press axis and extending in a plane normal thereto 4 and within the working stroke of the reciprocal platen and comprising integrally formed truss means for distributing the load on the fixed platen equally to the ends of the columns as axial forces including a truss head connected to the fixed platen at the press axis,

a plurality of truss arms each extending diagonally .from the truss head and connected to the end of one of said columns and horizontal members extending laterally between the ends of each column and interconnecting each truss arm so as to absorb any bilateral forces transmitted to the column, each truss arm being connected at the point where two of the horizontal members adjoin each other so as to provide open spaces between the truss arms and the horizontal members.

2. A four column press according to claim 1 wherein the fixed platen is mounted above the bed and the reciprocal platen on the bed.

3. A four column press according to claim 2 wherein the truss arms extend diagonally upwardly and outwardly at an angle of about 45 with the press axis.

References Cited by the Examiner UNITED STATES PATENTS 425,510 4/1890 Jackson 29-252 1,461,093 7/ 1923 Kershner. 1,985,598 12/1934 Carver 100-269 X FOREIGN PATENTS 497,528 3/1919 France.

544,461 6/ 1922 France.

254,909 1/ 1949 Switzerland.

BILLY J. WILI-IITE, Primary Examiner.

Claims

1. A FOUR COLUMN PRESS INCLUDING A BED RESTRAINED AT THE ENDS OF FOUR COLUMNS EXTENDING THEREFROM AND A PAIR OF PLATENS SUPPORTED IN RELATION TO THE BED SUCH THAT ONE IS FIXED AND THE OTHER IS RECIPROCAL RELATIVE THERETO, SAID FIXED PLATEN BEING POSITIONED SYMMETRICALLY WITH RESPCT TO THE PRESS AXIS AND EXTENDING IN A PLANE NORMAL THERETO AND WITHIN THE WORKING STROKE OF THE RECIPROCAL PLATEN AND COMPRISING INTEGRALLY FORMED TRUSS MEANS FOR DISTRIBUTING THE LOAD ON THE FIXED PLATEN EQUALLY TO THE ENDS OF THE COLUMNS AS AXIAL FORCES INCLUDING A TRUSS HEAD CONNECTED TO THE FIXED PLATEN AT THE PRESS AXIS, A PLURALITY OF TRUSS ARMS EACH EXTENDING DIAGONALLY FROM THE TRUSS HEAD AND CONNECTED TO THE END OF ONE OF SAID COLUMNS AND HORIZONTAL MEMBERS EXTENDING LATERALLY BETWEEN THE ENDS OF EACH COLUMN AND INTERCONNECTING EACH TRUSS ARM SO AS TO ABSORB ANY BILATERAL FORCES TRANSMITTED TO THE COLUMN, EACH TRUSS ARM BEING CONNECTED AT THE POINT WHERE TWO OF THE HORIZONTAL MEMBERS ADJOIN EACH OTHER SO AS TO PROVIDE OPEN SPACES BETWEEN THE TRUSS ARMS AND THE HORIZONTAL MEMBERS.