US3581656A

US3581656A - Prestressed press

Info

Publication number: US3581656A
Application number: US832193A
Authority: US
Inventors: Lambros Pappas; Eugene E Grankowski
Original assignee: Verson Allsteel Press Co
Current assignee: Allied Products Corp
Priority date: 1969-06-11
Filing date: 1969-06-11
Publication date: 1971-06-01
Anticipated expiration: 1988-06-01
Also published as: DE2020120A1; CA948477A; FR2045976A1; BR7019589D0; BE751336A; SE372730B; GB1312476A

Abstract

A prestressed press, including a bed member, a crown member and a ram carried by one of said members for performing a work function between the ram and the other of said members, is provided with a plurality of downwardly facing saddles on the bed member and a plurality of upwardly facing saddles on the crown member. A plurality of tension members extend between and along the sides of the bed member and the crown member beyond the saddles thereon and they have offsets therein respectively engaging the downwardly facing saddles on the bed member and the upwardly facing saddles on the crown member. A plurality of compression members are interposed between the bed member and the crown member, and shim means are arranged between the plurality of compression members and at least one of said bed and crown members for maintaining tension in said plurality of tension members and compression in said plurality of compression members.

Description

United States Patent [72] lnventors Lambros Pappas;

Eugene E. Grankowski, both of Chicago, Ill. [211 App]. No. 832,193 [22] Filed June 11, 1969 [4S] Patented June 1, 1971 [73] Assignee Verson Allsteel Press Company Chicago, Ill.

[54] PRESTRESSED PRESS 15 Claims, 6 Drawing Figs.

[52] U.S. Cl 100/214, 29/404, 29/446, 72/455, 100/269 [51] Int. Cl 133% 15/04 [501 Field of Search 100/214, 269; 29/446, 454; 72/455 [56] References Cited UNITED STATES PATENTS 1,872,115 8/1932 Byerlein 29/404 1,974,148 9/1934 Byerlein 100/214 3,154,006 l0 /1964 Novak 100/214X 3,210,837 10/1965 Hassellof ABSTRACT: A prestressed press, including a bed member, a crown member and a ram carried by one of said members for performing a work function between the ram and the other of said members, is provided with a plurality of downwardly facing saddles on the bed member and a plurality of upwardly facing saddles on the crown member. A plurality of tension members extend between and along the sides of the bed member and the crown member beyond the saddles thereon and they have offsets therein respectively engaging the downwardly facing saddles on the bed member and the upwardly facing saddles on the crown member. A plurality of compression members are interposed between the bed member and the crown member, and shim means are arranged between the plurality of compression members and at least one of said bed and crown members for maintaining tension in said plurality of tension members and compression in said plurality of compression members.

Patented June 1, 1971 3,581,656

5 Sheets-Sheet I5 JambrwJ/L 7% as @ZWE Grwzkii' PRESTRESSED PRESS Prestressed presses in the prior art usually include a bed member, a crown member, columns interposed between those members and.threaded tie rods extending through the bed member, the crown member and the columns, tie rod nuts being threaded onto the tie rods for tensioning the same and for compressing the bed and crown members and the columns to provide a rigid structure for restraining high work function forces. However, threaded tie rods have an inherently high stress concentration factor in the area of the threads, requiring heavy tie rod and nut constructions and heavy cumbersome frames.

The principal object of this invention is to provide an improved prestressed press which minimizes the disadvantages of the aforementioned prior art prestressed presses, which eliminates the need for threaded tie rods and their inherently high stress concentration factor, and which provides a more compact frame requiring less weight.

Briefly, the prestressed press of this invention basically includes a bed member, a crown member and a ram carried by one of said members for performing a work function between the ram and the other of said members. While this invention is applicable to mechanical presses having a power driven crank or the like for operating the ram, it finds particular utility ina hydraulic press where the ram is operated by a hydraulic cylinder. The hydraulic cylinder may be in the crown member of the press forforcing the ram downwardly toward the bed member of the press, or it may be in the bed member of the press for forcing the ram upwardly toward the crown member of the press. For purposes of illustration, the hydraulic cylinder is disclosed herein as being in the bed member.

The prestressed press is provided with a plurality of downwardly facing saddles on the bed member and a plurality of upwardly facing saddles on the crown member. A plurality of tension members extend between and along the sides of the bed member and the crown .member beyond the saddles thereon and they have offsets therein respectively engaging the downwardly'facing saddles on the bed member and the upwardly facing saddles on the crown member. A plurality of compression members are interposed between the bed member and the crown member, and shim means are arranged between the plurality of compression members and at least one of said bed and crown members for maintaining tension in said plurality of tension members and compression in said plurality of compression members.

In prestressingthe press, preferably, the ram isbIocked against said other of said bed and crown members, pressure above the rated capacity of the press is applied to the ram to tension and stretch the plurality of tension members, the shim means between the plurality of compression members and at least one of said bed and crown members are manipulated to take up for the tensioned and stretched condition of the plurality of tension members, and then the pressure applied to the ram is removed and the blocking between the ram and the other of said bed and crown members is removed, the shim means thereafter'maintaining tension in the plurality of tension members and compression in the plurality of compression members.

The shim means are preferably wedge blocks which are driven into place. The upwardly and downwardly facing saddles are preferably substantially cylindrically convex and the offsets in the plurality of tension members which engage the saddles are preferably substantially cylindrically concave to reduce stress concentrations thereat. The ends of the plurality of tension members adjacent the bed member and the crown member are preferably clamped together to counteract the moments of force in the tension members about the offsets therein which engage the saddles.

Further objects of this invention reside in the details of construction of the prestressed press of this invention and in the cooperative relationships between the component parts thereof.

Other objects and-advantages of this invention will become apparent to those skilled in the art upon reference to the accompanying specification, claims and drawings in which:

FIG. l is a front elevational view of one form of this invention;

FIG. 2 is a side elevational view of the prestressed press looking from the right of FIG. 1;

FIG. 3 is an enlarged vertical sectional view taken substantially along the line 3-3 of FIG. 2, the bottom portion of FIG. 3, however, illustrating a modified construction which is used in the prestressed press of FIG. 5;

FIG. 4 is a horizontal sectional view through the prestressed press and taken substantially along the line 4-4 of FIG. 1;

FIG. 5 is a front elevational view of another form of the prestressed press of this invention and is similar to FIG. I; and

FIG. 6 is a horizontal sectional view through the prestressed press of FIG. 5 and taken substantially along the line 6-6 of FIG. 5.

Referring first to FIGS. 1, 2, 3 and 4, one form of the prestressed press of this invention is generally designated at 10. It includes a supporting base having a pair of support structures 11 spanned by a bed member 15 provided with brackets 12 over each support structure and mounted on a foundation 13 as bybolts or the like. The bed member 15 is suitable secured tothe'supporting base as by bolts or the like. It further includes a ram or platen 19 associated with the bed member 15 and a crown member 20 above the bed member 15. The ram or platen 19 may be operated in any suitable manner and it is illustrated herein as being operated by a hydraulic cylinder which is formed in the bed member 15. In this-respect the hydraulic cylinder includes a cylinder 16 of large diameter and a cylinder 17 of small diameter. A piston 18 is arranged within the

cylinders

16 and 17 and is moved upwardly by means of hydraulic pressure applied therebelow. As illustrated herein, the topof the piston 18 forms the-ram or platen 19 for performing the work function of the press, but within the purview of this invention, the ram or platen 19 may be separate from the piston 18 and separately guided by gibs or the like. The crownmember 20 may also be provided with a platen 21 and the work function is accomplished between the platen or ram 19 of the platen 21 upon application of hydraulic pressure below the piston 18. The opening above the cylinder 16 of large diameter may be closed by a suitable annular plate 22, the piston 18 extending therethrough.

The bed member 15 which comprises the hydraulic cylinder apparatus is provided with a pair of downwardly facing saddles 25, the saddles preferably being cylindrically convex. .The crown member 20 is also provided with a pair of upwardly facing saddles 26 which also are preferably cylindrically convex. A pair of tensionmembers 27 extend between and along the sides of the bed member 15 and the crown member 20 beyond the

saddles

25 and 26 thereon, as indicated at 28 and 29 respectively. These tension members 27 have

offsets

30 and 31 therein respectively engaging the downwardly facing saddles 25 on the bed member 15 and the upwardly facing saddles 26 on the crown member 20. Here, the

offsets

30 and 31 are preferably cylindrically concave to mate with the cylindrically convex surfaces of

thesaddles

25 and 26 to reduce stress concentrations at these points.

A pair of compression members 35 are interposed between the bed member 15 and the crown member 20 adjacent the tension members 27. Arranged between the compression members 35 and the crown member 20 are shim means which may take the form of wedge blocks 36.

In prestressing the press, preferably, the ram or platen 19 is blocked by suitable-blocks (not shown) against the platen 21 of the crown member 20 and hydraulic pressure above the rated capacity of the press is applied to the piston 18 to tension and stretch the tension members 27. The wedge blocks 36 comprising the shim means are manipulated as by driving the same to take up the gap resulting from the tensioned and stretched condition of the tension members 27. The pressure applied to the piston l8.is then removed and the blocking between the platen or ram 19 and the platen 21 is removed with the result that tension is maintained in the tension members 27 and compression is maintained in the compression members 35.

As shown more clearly in FIGS. 1 and 2, the bottom portions 28 of the tension members 27 have tension bolts 38 extending therethrough and are drawn toward each other by means of nuts 39 threaded on the bolts 38 against sleeves 40. This clamping of the lower ends 28 of the tension members 27 counteracts the moments of force in the tension members 27 about the offsets 30 which engage the saddles 25.

In a like manner as illustrated in FlGS. l, 2 and 4, the upper ends 29 of the tension members 27 have tension bolts 42 extending therethrough and are drawn towards each other by nuts 43 threaded on to the bolts 42 against sleeves 44. Here, also this clamping of the upper ends 29 of the tension members 27 counteracts the moments of force in the tension members 27 about the offsets 31 therein which engage the saddles 26.

The bed member is provided with brackets 46 on opposite sides of the tension members 27 and the crown member is provided with brackets 47 on opposite sides of the tension members 27 for the purpose of positioning and aligning the tension members 27 with respect to the bed member 15 and the crown member 20.

The other form of the invention illustrated in FIGS. 5 and 6 and in the lower portion of FIG. 3 is the same as the form of the invention illustrated in FIGS. 1 to 4 with the exception that a different structure is used for clamping together the lower ends 28 and the upper ends 29 of the tension members 27. Accordingly, like reference characters have been utilized for like parts and a further description is, therefore, not considered necessary. In the modified form of the prestressed hydraulic press which is generally designated at 50, the lower ends 28 of the tension members 27 are provided with outwardly facing shoulders 52. A plate 53 spans the lower ends 28 of the tension members 27 and it is provided with a pair of inwardly facing shoulders 54 adjacent the shoulders 52. Shim means in the form of wedge blocks 55 are interposed between the

shoulders

52 and 54 and as they are driven, the lower ends 28 of the tension members 27 are drawn toward each other to counteract the moments of force in the tension members about the offsets therein which engage the saddles 25. The lower ends 28 of the tension member are provided with threaded studs 56 and the transverse plate 53 is held against the lower ends 28 of the tension members 27 by means of sleeves 57 and nuts 58 threaded on the studs 56.

In a like manner as shown in FIGS. 5 and 6, the upper ends 29 of the tension members 27 have outwardly facing shoulders 60. A plate 61 arranged across the upper ends 29 of the tension members 27 has inwardly facing shoulders 62 adjacent the shoulders 60 and shim means in the form of wedge blocks 63 operate when driven home to draw the upper ends 29 of the tension members 27 toward each other for the purpose of counteracting the moments of force in the tension members 27 about the offsets 31 therein which engage the saddles 26. The ends 29 of the tension members 27 carry studs 65 and the plate 61 is secured against the ends 29 of the tension member by sleeves 66 and nuts 67 threaded on the studs 65.

While for purposes of illustration, one basic form of this invention has been disclosed, other forms thereof may become apparent to those skilled in the art upon reference to this disclosure and, therefore, this invention is to be limited only by the scope of the appended claims.

We claim:

1. In a prestressed press including a bed member, a crown member and a ram carried by one of said members for performing a work function between the ram and the other of said members, the improvement comprising, a plurality of downwardly facing saddles on the bed member, a plurality of upwardly facing saddles on the crown member, a plurality of tension members extending between and along the sides of the bed member and crown member beyond the saddles thereon and having offsets therein respectively engaging the downwardly facing saddles on the bed member and the upwardly facing saddles on the crown member, a plurality of compression members interposed between the bed member and the crown member, and shim means between the plurality of compression members and at least one of said bed and crown members for maintaining tension in said plurality of tension members and compression in said plurality of compression members.

2. A prestressed press as defined in claim 1 wherein said shim means comprise wedge blocks which are driven into place.

3. A prestressed press as defined in claim 2 wherein said downwardly and upwardly facing saddles are substantially cylindrically convex and said offsets in the plurality of tension members which engage the saddles are substantially cylindrically concave, whereby stress concentrations are reduced to a minimum.

4. A prestressed press as defined in claim 1 wherein said downwardly and upwardly facing saddles are substantially cylindrically convex and said offsets in the plurality of tension members which engage the saddles are substantially cylindrically concave, whereby stress concentrations are reduced to a minimum.

5. A prestressed press as defined in claim 4 comprising means for clamping together the lower ends of the plurality of tension members adjacent the bed member and means for clamping together the upper ends of the plurality of tension members adjacent the crown member to counteract the m0- ments of forces in the plurality of tension members about the offsets therein which engage the saddles.

6. A prestressed press as defined in claim 5 wherein said clamping means comprise tension rods extending respectively between the upper ends and the lower ends of the plurality of tension members.

7. A prestressed press as defined in claim 5 where said clamping means comprise outwardly facing shoulders on the ends of the plurality of tension members, plates overlying the upper ends of the plurality of tension members and having inwardly facing shoulders adjacent the outwardly facing shoulders on the tension members, and shim means interposed between the shoulders on the tension members and on the plates.

8. A prestressed press as defined in claim 7 including bolts extending through the plates into the plurality of tension members outwardly beyond the shoulders thereon to secure the plates to the tension members.

9. A prestressed press as defined in claim 1 comprising means for clamping together the lower ends of the plurality of tension members adjacent the bed member and means for clamping together the upper ends of the plurality of tension members adjacent the crown member to counteract the moments of forces in the plurality of tension members about the offsets therein which engage the saddles.

10. A prestressed press as defined in claim 9 wherein said clamping means comprise tension rods extending respectively between the upper ends and the lower ends of the plurality of tension members.

11. A prestressed press as defined in claim 9 wherein said clamping means comprise outwardly facing shoulders on the ends of the plurality of tension members, plates overlying the upper ends of the plurality of tension members and having inwardly facing shoulders adjacent the outwardly facing shoulders on the tension members, and shim means interposed between the shoulders on the tension members and on the plates 12. A prestressed press as defined in claim 11 including bolts extending through the plates into the plurality of tension members outwardly beyond the shoulders thereon to secure the plates to the tension members.

13. A prestressed press as defined in claim 1 wherein said ram is hydraulically operated, and wherein movement of said ram is blocked against said other of said members while hydraulic pressure above the rated capacity is applied to said ram for initially tensioning said plurality of tension members.

14. The method of prestressing a prestressed press including a bed member, a crown member and a ram carried by one of said members for performing a work function between the ram and the other of said members, a plurality of downwardly facing saddles on the bed member, a plurality of upwardly facing saddles on the crown member, a plurality of tension members extending between and along the sides of the bed member.

and crown member beyond the saddles thereon and having offsets therein respectively engaging the downwardly facing saddles of the bed member and the upwardly facing saddles on the crown member, a plurality of compression members interposed between the'bed member and the crown member, and shim means between the plurality of compression members and at least one of, said bed and crown members for maintaining tension in said plurality of tension members and compression in said plurality of compression members, comprising blocking the ram against said other of said bed and crown members, applying pressure above the rated capacity of the press to stretch and initially tension the plurality of tension members, manipulating the shim means to take up for the stretched condition of the plurality of tension members, and removing said applied pressure and the blocking between the ram and said other of said members.

15. A prestressed press including a bed member, a crown member and'a ram carried by one of said members for performing a work function between the ram and the other of said members, a plurality of downwardly facing saddles on the bed member, a plurality of upwardly facing saddles on the crown member, a plurality of tension members extending between and along the sides of the bed member and crown member beyond the saddles thereon and having offsets therein respectively engaging the downwardly facing saddles on the bed member and the upwardly facing saddles on the crown member, a plurality of compression members interposed between the bed member and the crown member, and shim means between the plurality of compression members and at least one of said bed and crown members for maintaining tension in said plurality of tension members and compression in said plurality of compression members, the tensioning of said tension members and the compressing of said compression members and, hence, the prestressing of the press resulting from blocking the ram against said other of said bed and crown members, applying pressure above the rated capacity of the press to stretch and initially tension the plurality of tension members, manipulating the shim means to take up for the stretched condition of the plurality of tension members, and removing said applied pressure and the blocking between the ram and said other of said members.

Claims

5. A prestressed press as defined in claim 4 comprising means for clamping together the lower ends of the plurality of tension members adjacent the bed member and means for clamping together the upper ends of the plurality of tension members adjacent the crown member to counteract the moments of forces in the plurality of tension members about the offsets therein which engage the saddles.

11. A prestressed press as defined in claim 9 wherein said clamping means comprise outwardly facing shoulders on the ends of the plurality of tension members, plates overlying the upper ends of the plurality of tension members and having inwardly facing shoulders adjacent the outwardly facing shoulders on the tension members, and shim means interposed between the shoulders on the tension members and on the plates .

12. A prestressed press as defined in claim 11 including bolts extending through the plates into the plurality of tension members outwardly beyond the shoulders thereon to secure the plates to the tension members.

14. The method of prestressing a prestressed press including a bed member, a crown member and a ram carried by one of said members for performing a work function between the ram and the other of said members, a plurality of downwardly facing saddles on the bed member, a plurality of upwardly facing saddles on the crown member, a plurality of tension members extending between and along the sides of the bed member and crown member beyond the saddles thereon and having offsets therein respectively engaging the downwardly facing saddles of the bed member and the upwardly facing saddles on the crown member, a plurality of compression members interposed between the bed member and the crown member, and shim means between the plurality of compression members and at least one of said bed and crown members for maintaining tension in said plurality of tension members and compression in said plurality of compression members, comprising blocking the ram against said other of said bed and crown members, applying pressure above the rated capacity of the press to stretch and initially tension the plurality of tension members, manipulating the shim means to take up for the stretched condition of the plurality of tension members, and removing said applied pressure and the blocking between the ram and said other of said members.

15. A prestressed press including a bed member, a crown member and a ram carried by one of said members for performing a work function between the ram and the other of said members, a plurality of downwardly facing saddles on the bed member, a plurality of upwardly facing saddles on the crown member, a plurality of tension members extending between and along the sides of the bed member and crown member beyond the saddles thereon and having offsets therein respectively engaging the downwardly facing saddles on the bed member and the upwardly facing saddles on the crown member, a plurality of compression members interposed between the bed member and the crown member, and shim means between the plurality of compression members and at least one of said bed and crown members for maintaining tension in said plurality of tension members and compression in said plurality of compression membErs, the tensioning of said tension members and the compressing of said compression members and, hence, the prestressing of the press resulting from blocking the ram against said other of said bed and crown members, applying pressure above the rated capacity of the press to stretch and initially tension the plurality of tension members, manipulating the shim means to take up for the stretched condition of the plurality of tension members, and removing said applied pressure and the blocking between the ram and said other of said members.