US3875778A

US3875778A - Hydraulic press

Info

Publication number: US3875778A
Application number: US407506A
Authority: US
Inventors: Keijo Eugen Hellgren
Original assignee: ASEA AB
Current assignee: ABB Norden Holding AB
Priority date: 1972-11-14
Filing date: 1973-10-18
Publication date: 1975-04-08
Anticipated expiration: 1992-04-08
Also published as: JPS49135278A; SE368173B

Abstract

In an hydraulic press for forming sheet material which includes a press stand with a recess therein and an expansible pressure bag and a pad of elastic material within the recess, and which has an operating space below the recess into which a trough-shaped support member for tools and workpieces can be inserted, metallic strip seals are provided which overlie the edges of the pad and extend over the wall portions at either end of the recesses. Such wall portions are provided with grooves, into which flanges on the outer ends of the strip seals engage. The strip seals are supported by hat-shaped elements arranged in recesses in such wall portions which are secured to the strip seals and are held in position by coil springs engaging bolts secured in the recesses.

Description

United States Patent Hellgren Apr. 8, 1975 [S ll HYDRAULKC PRESS 3.545.3-ll l2/l97U Grunkowski et all 72/63 [75] lmcmor' gigg fi Hellgren \HMLMS Primary E.i'umiizer-Richard .l. Herhst (73] Assignee: Allmanna Svenska Elektriska 57 ABSTRACT Akuebolage imam Sweden ln Llll hydraulic press for forming sheet material which [22} Filed: Oct. I8. 1973 includes a press stand with a recess therein and an ex unsihle ressure hti and u ad of elastic material [2]] App! 407506 iiithin this recess. an?! which has lln operating space below the recess into which it trough-shaped support [30] Foreign Application Priority Data member for tools and workpieces can be inserted. me-

[4 1973 Sweden 4747/73 ttillic strip seals are provided which overlie the edges of the pad and extend over the wall portions at either 52 s CL I I V I g I l I I r 4 t v 72 3 end of the recesses. Such wall portions are provided 5 H h. C] H. N n 22/12 with grooves. into which flanges on the outer ends of [58] Field of Search 72/63; 100/21 1 the Strip W18 engage The strip M15 m pp y hat-shaped elements arranged in recesses in such wall [56] References Cited portions which are secured to the strip seals and are UNITED STATES PATENTS held in position by coil springs engaging bolts secured r in the recesses. 1696.184 12/1954 Demurest 72163 177L850 Il/I956 Whcelon 4. 72/63 4 Claims. 6 Drawing Figures PATENTEDAPR 8|H75 $875,778

22 2 2/b 2/0 38 40 2/ 2/c 200 2/d 42 25 Fig. 5

22 2 21b 21a 38 40 2/ 2/c 20o 2/d 42 25 Fig.6

booooo oooo HYDRAULIC PRESS BACKGROUND OF THE INVENTION l. Field of the Invention The present invention relates to a press with a very large working area for forming sheet-metal by means of a diaphragm which is pressed against pieces of sheet metal resting on a forming block. Aircraft parts such as ribs and the like can be manufactured in such a press.

2. The Prior Art The press according to the invention comprises a press stand having a window opening with substantially rectangular cross-section. A frame or plate is suspended in the press stand and in said frame or plate a diaphragm is attached forming a pressure bag. On the underside of the diaphragm there is a thick layer of elastic material which forms a pad forming workpieces. workpieces are placed at the bottom of a troughshaped support member which is pushed into the operating space below the plate with the pressure bag and pad. after which the pressure bag is supplied with pressure medium. This will cause the pad to be pressed against one or more workpieces at the bottom of the trough-shaped support member.

There exist very great problems in such presses in preventing the pad from being pressed out through gaps between the support member and the surrounding construction elements in presses. Particularly great are the problems of preventing the pad from being pressed out through the gap between the upper surface of the support member and the support plate of the pressure bag at the end openings of the press.

In known constructions an L-shaped strip is used which is attached in a resilient manner in the past of the support plate of the pressure bag which forms the end wall in the space where the pressure bag and its pad are arranged. One flange of the L-shaped strip is directly attached by bolts in the end wall of the support plate and the elasticity is obtained by bending the flange. By providing notches in the flange an increase in the length of the spring is achieved. The forces which affect the strip in the pressing are great and sometimes cause the attachment bolts to burst after only a short time. It has also been difficult to make the resilient parts of the strip flange sufficiently rigid. These bolt and strip ruptures have caused prolonged shut-downs.

SUMMARY OF THE INVENTION According to the invention the strip is constructed and arranged in such a way that all forces affecting the strip in the axial directions of the press are transmitted to the wall which defines the space of the pressure bag, and the resilient attachment of the strip is such that the attachment bolts are only subjected to tensile forces. The strip seal is made with a U-shaped portion with a flange projecting into a slot in said wall.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described more closely with reference to the accompanying drawings.

FIG. 1 shows a side view of a press plant;

FIG. 2 shows a section on the line AA of FIG. I;

FIG. 3 is a vertical longitudinal section on the line 3-8 of FIG. 2;

FIG. 4 shows on a larger scale a section through the strip seal and adjacent parts on the same line BB; and

FIGS. 5 and 6 show the position of the strip sea] at two moments during a press operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings. I designates a press and 2 a trough shaped support member on which workpieces can be placed. The support member is provided with transport rolls 3 running on tracks 4. The support member is displaceable between the position shown in FIG. I, where pressed sheet-metal pieces are removed and new pieces are put on forms, and a position pushed into the press where the press pad forms the sheet-metal pieces. The press shown is of the kind having a press stand which is constructed of an upper yoke I0, a lower yoke II and two intermediate spaces 12 which are kept together by a pre-stressed strip sheath I3. This sheath is surrounded by a protective plate 14.

The press rests on a support I5 having bearing plate beds adjusted to the press. The yokes and spaces form a rectangular window opening in the press. In the space within the press a plate 16 is mounted in the yoke 10 by means of bolts now shown. In a recess in said plate a diaphragm I7 is attached with the help of the plate 18 and the bolts I9 so that a pressure bag is formed. The space between the diaphragm I7 and the plate I8 communicates with a pressure source (not shown] through pipes 29 by way of valves and pipes (not shown). The diaphragm is connected to a thick pad 20 of elastic material. Adjacent the recess where the diaphragm and pad are arranged there is a support strip 2I which is intended to prevent the pad 20 from being pressed out through the gap 22 between the plate I6 and the upper surface of the trough-shaped support member 2 during a press operation when the pad is pressed against the plate 23 on the forming block 24 in the recess 25 in the support member 2 by the press me dium in the pressure bag formed of the diaphragm I7 and the plate 18.

The wheels 3 of the support member 2 are mounted on axle pins 26 between the brackets 27. In the tracks 4 nearest the press there are plates 31 supported by springs 30, said plates having a lifting force somewhat exceeding the weight of the support member 2 with the forming block 24 and the workpiece 23. In this way these plates yield downwardly when the pad 20 exerts a downward force against the workpiece 23 on the forming block 24 resting on the bottom 32 of the recess 25. The support member 2 will then rest against the yoke 11, which will thus take up the main part of the downward force.

The strip seal 21, a part of which overlaps the edge of the pad 20, is E-shaped and is provided with a web 210, a flange 21b. a flange 21c and a flange 21d. The pad 20 has a shape adapted to the shape of the strip seal 21, with a part 200 projecting between the flanges 21c and 21d. In the outer wall 16a of the plate 16, that is, the wall portion at the end of the recess. there is a slot 35. The flange 21b projects into this slotv The flange 21c rests against the vertical. inner surface 36 of the wall 16a. In the wall there are bores 37. Through an aperture 38 in the web 21a. a hat-shaped sleeve 39 projects into the bore 37. The strip seal 21 is suspended from the wall 16a with the help of a bolt 40 and a pres sure spring 41 and said sleeve 39. When pushing in and pulling out the trough-shaped support member 2, the pad 20 and the strip are in the position shown in FIGS.

3 and 4. When pressure medium is supplied to the pres sure bag the diaphragm l7 and the pad are first stretched and the pad tends to pull the strips seal 2] in wards [see FIG. 5) The resulting tensile force are transmitted by way of the flange Zlb and the wall of the slot to the wall 161:. When the pad is pressed against the support member 2 it will simultaneously be pressed against the strip seal 2] and the wall 36. The strip seal 2] will then be pressed against the surface 42 of the support member. that is. the wall portion at the end of the trough as well as the wall 36 and will therefore bridge over the gap 22. thus preventing the pad from being pressed out through the gap and being destroyed By means of the present invention all the forces in the horizontal direction which act on the strip seal are directly transmitted to the wall 16a from the flanges 22c and 21b. respectively. The attachment bolts 40 will then only absorb tensile forces These are limited to a value determined by the springs 41. The whole strip 21 will rest on the support member 2, so the web Zlu will not be subjected to considerable fexural stresses as has been the case in previous press constructions, A satis factory length of service can be obtained despite the use of more simple construction of the strip seal I claim:

1. Hydraulic press for forming sheet material comprising a press stand including a first part having a re cess therein and having walls at each end of the recess with transverse faces an expansible pressure bag and a pad of elastic material within the recess. said press stand including a second part opposite the first part and spaced therefrom to provide an operating space extending through the press stand having end openings, a support member for tools and workpieces insertable into said operating space having transverse faces opposable to the transverse faces of the first part, grooves in said transverse faces substantially parallel to the plane of the end openings, metalli strip seals adjacent the end openings of the operating space overlying the edges of the pad end having flanges engaging in the grooves and having portions between the transverse faces of the first part and the transverse faces of the suport member, said portions overlying the transverse faces of the support part and means mounting the strip seals on the first part 2. Press as claimed in claim I, in which the mounting means mount the strip seals for movement towards and away from the transverse faces of the first part.

3. Press as claimed in claim 1. in which the mounting means mount the strip seals for movement towards and away from the transverse faces of the first part. the mounting means being resilient and resisting movement of the strip seals away from the transverse faces of the support part,

4. Press as claimed in claim 3, in which the transverse faces of the first part have notches therein and the mounting means comprises hatshaped sleeves which are attached by their lower parts in the strip seals and which project into said notches, pressure springs in said sleeves and bolts attached in the transverse faces engaging said springs.

Claims

1. Hydraulic press for forming sheet material comprising a press stand including a first part having a recess therein and having walls at each end of the recess with transverse faces, an expansible pressure bag and a pad of elastic material within the recess, said press stand including a second part opposite the first part and spaced therefrom to provide an operating space extending through the press stand having end openings, a support member for tools and workpieces insertable into said operating space having transverse faces opposable to the transverse faces of the first part, grooves in said transverse faces substantially parallel to the plane of the end openings, metalli strip seals adjacent the end opening of the operating space overlying the edges of the pad end having flanges engaging in the grooves and having portions between the transverse faces of the first part and the transverse faces of the suport member, said portions overlying the transverse faces of the support part and means mounting the strip seals on the first part.

2. Press as claimed in claim 1, in which the mounting means mount the strip seals for movement towards and away from the transverse faces of the first part.

3. Press as claimed in claim 1, in which the mounting means mount the strip seals for movement towards and away from the transverse faces of the first part, the mounting means being resilient and resisting movement of the strip seals away from the transverse faces of the support part.

4. Press as claimed in claim 3, in which the transverse faces of the first part have notches therein and the mounting means comprises hat-shaped sleeves which are attached by their lower parts in the strip seals and which project into said notches, pressure springs in said sleeves and bolts attached in the transverse faces engaging said springs.