FRAME FOR A PRESS MACHINE

Abstract: A frame for a press machine having a bed, upstanding columns affixed to the bed at the four corners thereof, and a crown affixed to the upper ends of the columns, and a slide movably connected to said crown, comprises four upstanding members integrally formed with the bed at the four corners thereof and fixedly supporting siad columns, and means between said upstanding members at least in the larger ones of the spaces between sais upstanding members, each engaging a pair of said upstanding members so as to create reaction forces counter­ acting a downward deflection of the bed and an inward deflect­ ion of said upstanding members and of said columns cennected thereto, upon operation of the press machine. Said means may be ribs integrally formed with the bed, or wedge members engaging the opposite end faces of a bolster mounted to the bed.

Description: The present invention relates to a frame for a press machine, and more particularly to a frame of a press machine which prevents the press bed and columns from deforming under a working load. A prior art frame for a straight-side press machine, as shown in Fig. 7, has a frame structure including a bed 1, columns 2 set up in front and rear as well as on left and right of the bed 1, namely on the four corners of the bed 1, a crown 3 disposed on the columns 2, and tie rods 4 for fastening together the bed 1, the columns 2 and the crown 3. A bolster 5 is mounted on the bed 1 in the center thereof and is bolted to the bed 1, and a slide 6 is so constructed that it can move up and down relative to the bolster between the columns. There are provided lower and upper dies 7 and 8 on the bolster and on the slide, respectively, and between the dies 7 and 6 pressing is performed. When the press machine is under working load, the bed 1 and the slide 6 deflect in the vertical direction by δ₁ and δ₂, respectively, as shown by dashed line, and the columns 2 deform inside toward the center of the press, being influenced by the deflection of the bed, as shown by δ₃. The deformation of the bed and columns during the press operation will be the factor of lowering dynamic accuracy of the press such as punch failure, and particularly the deformation of the the columns deforms the guiding surfaces of the slide, thereby causing the slide movement out of way and lowering accuracy of products. From GB-A-1 139 189 a four column power press is known including a reciprocable platen, a fixed platen positioned symmetrically with respect to the press axis and extending in a plane normal thereto, a plurality of truss members each connected at an inner end to the fixed platen adjacent the center thereof and diverging axially and radially outwardly therefrom and being connected at the outer end to a column, and a plurality of tension members each connected to and extending between adjacent outer ends of the trusses, the arrangement being such that during use of the press, the load on the fixed platen is resolved into force components placing the truss members under compression, which components are further resolved into lateral and axial force components at each columns with the lateral force components being absorbed by the tension members. Furthermore, the truss members ensure that there is little tendency for the columns to bow or bend since the columns are loaded in a primarily axial direction, the truss members deflecting uniformly under load to absorb the bending forces. It is the object of the present invention to provide a frame for a press machine which decreases the bed deflection and column deformation. This object is attained by a press frame as set forth in claim 1. Preferred embodiments of the invention are subject matter the dependent claims. In following, the invention will be explained with reference to the accompanying drawings in which: Fig. 1 is a plan view of a bed of a press machine, Fig. 2 is a sectional view taken on line II-II of Fig. 1, Fig. 3 is a sectional view taken on line III-III of Fig. 1, Fig. 4 is a front view of the overall press machine, Fig. 5 is a front view of a bed, partly shown in section, Fig. 6 is a detailed view of part A of Fig. 5, and Fig. 7 is a front view of a press machine of the prior art, clearly showing the drawbacks thereof overcome by the present invention. Referring to Figs. 1 to 4, a press machine comprises a bed 10, upstanding members 11 formed integrally with the bed 10 on the four corners thereof, columns 12 provided on the upstanding members 11 and connected therewith, a crown 13 provided on the columns 12, and tie rods 14 extending through said bed 10, upstanding members 11, columns 12 and crown 13 to fix these parts together. The upstanding members 11 are provided with rib members 15 in front and rear of the press machine. The rib members 15 may preferably be provided where the distance between the upstanding members 11 is longer, and the rib members 15 are provided in the front and rear, because the distances between left and right upstanding members are longer than those between front and rear upstanding members. Further, the lower portion of the rib member 15 is integral with the bed. Positioned on the bed 10 is a bolster 16 which is brought by a fork lift or jack and is fixed to the bed 10. The press machine has a slide 17 which is mounted between the columns 12 in a vertically movable manner. An upper die 18 is provided on the lower surface of the slide 17, while a lower die 19 is provided on the upper surface of the bolster 16, and between the upper and lower dies 18 and 19, pressing is performed. When the press machine of the above structure starts to operate, the working load of the press tends to deflect the bed 10, and at the same time tends to deflect the columns 12 inwardly. The rib members 15 mounted to the upstanding members 11, however, prevent the upstanding members 11 and the columns 12 affixed thereto from collapsing inside and, accordingly, prevent the downward deflection of the bed 10, thereby improving dynamic accuracy of the press. Next, with reference to Figs. 5 and 6, the features of the invention will be explained. Upstanding members 21 are formed integrally with a bed 20 on the four corners thereof, and columns 22 are provided on the upstanding members 21 and connected therewith. Although the upper part of the columns 22 is omitted for simplicity of illustration, a crown is positioned on the columns and tie rods (not shown) are provided to fix the crown, columns and bed together, similarly with the press generally explained before. Further, a bolster 23 is positioned on the bed. Between the end faces of the bolster 23 and side walls 20a forming a part of the bed 20 and forming the lower portion of the upstanding members 21, there are provided a first wedge member 24 on one side and a second wedge member 25 on the opposite side of the bolster 23. The first wedge member 24 protrudes from the side wall 20a on the right side ( as seen from the front), extending along the entire width of the bolster 23 in the forward/rearward direction thereof, and being in contact with the end face of the bolster 23. As shown in Fig. 6, a protruding portion 26, constituting part of the second wedge member 25 protrudes from the side wall 20a on the left side of the bed 20 and extends along the entire width of the bolster 23 in the forward/rearward direction thereof at an elevation corresponding to the first wedge member 24. The second wedge member 25 further includes a fixed wedge portion 27 having an inclined surface of which the upper portion is gradually apart from the bed side. The fixed wedge portion 27 is partly fitted in a groove 28 formed on the end face of the bolster 23 and is fixed by a mounting bolt 29 so as to form a space between the fixed wedge portion 27 and the protruding portion 26. Disposed in the space between the protruding portion 26 and the fixed wedge portion 27, is a driving wedge portion 30 which is inclined in a reverse manner to the fixed wedge portion 27. By pushing the driving wedge portion 30 downward, the left and right end faces of the bolster 23 are restrained against the side walls 20a provided at the lower portions of the upstanding members 21 integrally formed with said bed 20. Further, the thus restrained bolster 23 is fixed to the bed 20 by bolting. Even in this case, when a force is applied to the bed 20 in the direction of deflecting it downward upon operation of the press machine applying a load, the side walls 20a of the bed support the bolster 23 by means of the first and second wedge members 24 and 25, thereby decreasing the deflection of the bed under the working load of the press. With the decrease of the deflection of the bed, there is also a decrease in the accompanying deflection of the columns 22. Consequently, the accuracy of the press can be improved.

Claims: A frame for a press machine, comprising a bed (20), four upstanding members (21) integrally formed therewith at the four corners thereof and each fixedly supporting an upstanding column (22), a crown affixed to the upper ends of said columns (22), and a slide movably connected to said crown, and means (23, 24, 25) provided between said upstanding members (21) at least in the larger ones of the spaces between said upstanding members (21), each engaging a pair of said upstanding members (21) so as to create reaction forces counteracting a downward deflection of said bed (20) and an inward deflection of said upstanding members (21) and of said columns (22) connected thereto upon operation of the press machine, said means (23, 24, 25) comprising a pair of wedge members (24, 25) and a bolster (23) positioned on the bed (20), each of said wedge members (24, 25) being positioned between one of said upstanding members (21) and an end face of said bolster (23). A frame as set forth in claim 1 wherein at least one of said wedge members (24, 25) includes at least a wedge portion (30) having an inclined surface and being so shaped that it has a wedging action when driven in downwardly. A frame as set forth in claim 2 wherein another wedge portion (27) having a surface inclined in a reverse manner to the first wedge portion (30) and being affixed to an associated end face of the bolster (23) is provided and is engaged by the first wedge portion (30) when the latter is driven in downwardly.

Inventors: NAKAMURA, YUICHI, SHIGA, MASAKATSU
Applicants: AIDA ENGINEERING LTD.
Application year: 1987
Main classification: B30B15
IPC codes: B30B15