WO2010000837A1

WO2010000837A1 - Press frame module

Info

Publication number: WO2010000837A1
Application number: PCT/EP2009/058410
Authority: WO
Inventors: Peter Sternersson; Kuno Nothin; Lars Eriksson
Original assignee: Presservice Ljungby Ab
Priority date: 2008-07-04
Filing date: 2009-07-03
Publication date: 2010-01-07
Also published as: EP2141006A1

Abstract

A press frame module for a press comprises a front plate (4) and a rear plate (6) parallely arranged to each other, spacer elements (16) arranged between the plates (4, 6), and a press platen (26), which is displaceable in a press chamber formed between the plates (4, 6). Each of the spacer elements (16) is a solid connecting bar having a center portion, forming a spacer, and end portions, said center portion having a larger cross sectional area than each of the end portions, and each of said end portions being received with a tight fit in a bore arranged in a corresponding one of said plates and being attached to that plate by means of a tightening element (18).

Description

PRESS FRAME MODULE

Field of the invention

The present invention relates to a press frame module for a press comprising a front plate and a rear plate parallely arranged to each other, spacer elements arranged between the plates, and a press platen, which is displaceable in a press chamber formed between the plates.

Background of the invention

There are many different constructions of press frames structures for presses. When manufacturing presses welding is often an undesirable operation as it affects the metallic properties and demands special post treatment. This makes assembly at the site of use difficult and requires transport of the often voluminous presses in an assembled form.

US 5 027 638 describes a force-resisting structure for a conventionally built press frame. This solid structure is unwelded and comprises metal plates connected and maintained in alignment by a pair of side plates. The plates are connected together with bolts, but the bolts do not participate in resisting the main structural loads. The purpose with this structure is to achieve a structure, where all parts are assembled by means of bolts without welding.

This structure is a complex construction with many different parts, such as upper and lower plates with intermediate wedges for transferring forces to load carrying parts. Further it does not allow side feeding of objects to be pressed.

Summary of the invention It is an object of the present invention to provide a press frame module which is easy and cost effective to produce and mount.

This and other objects that will be apparent from the following summary and description are achieved by a press frame module according to the appended claims. According to one aspect of the present invention, there is provided a press frame module for a press comprising a front plate and a rear plate parallely arranged to each other, spacer elements arranged between the plates, and a press platen, which is displaceable in a press chamber formed between the plates. Each of the spacer elements is a solid connecting bar having a center portion, forming a spacer, and end portions, said center portion having a larger cross sectional area than each of the end portions, and each of said end portions being received with a tight fit in a bore arranged in a corresponding one of said plates and being attached to that plate by means of a tightening element.

The tight fit of the end portions in combination with the engaging function of tightening devices provides for a robust press frame module. A press frame module that may be assembled in an easy manner is provided. Prefabhcation and post assembly at site is thus enabled, which in turn reduces transport costs. A further advantage is that no post treatment of the assembled frame module is required since the connecting bars are attached by means of a tightening element. Also, a press frame module that may be demounted in an easy manner is provided. Furthermore, a press frame which is easy to reconstruct and manufacture in different dimensions is provided. Each connecting bar is easily machined and preferably attached by means of screws or bolts, though it is also possible to use wedgeshaped elements, such as keys or cotters. Preferably, the tightening element is a screw, or a bolt, which is screwed into a blind hole in the end portion. Thus, a very robust and stable press frame module is provided. Also, assembling of a press frame module can be carried out in a very easy and controllable manner.

The plate thickness in an area around each of the bores is preferably larger than the length of the corresponding end portion. A clearance between the connecting bar and the screw is then achieved which enables the plate to be biased against the connecting bar in a very robust manner. The clearance enables the connecting bar to be biased against the plate and may thus even further improve the stability of the press frame module. Preferably, each bore, on the surface facing the opposite plate, has a surrounding circular recess forming a plane surface for receiving a connecting bar in a right-angled fashion. The recesses further improves the stability of the press frame module. Preferably, each of the end portions has a circular cross section.

Each of the end portions may have the shape of a cylinder.

In one embodiment each connecting bar is a solid circular bar with a larger diameter center part and smaller diameter ends, wherein each bore has a diameter of essentially the same diameter as the smaller diameter ends for receiving each end with a tight fit. With all bores machined exactly the same and with identical connecting bars this construction provides for a simple assembly with exactly spaced apart plates.

Preferably, each of the end portions has the shape of a frusto-cone, the cross sectional area of which is decreasing towards the free end of the end portion. Such frusto-conical end portions facilitate assembling and reassembling of the press module considerably. Furthermore, they contribute to even further improved stability of the press frame module since a more robust attachment of the connecting bar to the plate is achieved. In one embodiment at least one of said bores in the plates is provided with a sleeve inserted therein, the sleeve having an inner wall surface with the same shape as the corresponding frusto-conical end portion, in order to further facilitate mounting and demounting of a press frame module. This embodiment further has the advantage that the production cost of the plates in which the bores are arranged can be reduced since ordinary bores, such as cylindrical bores, may be formed in the plates even though the connecting bars have frusto-conical end portions. The sleeve may be formed from a different material than the plates and/or the connecting bars, which may enable further improvement of the press frame module stability. Further advantages and features of the present invention will be apparent from the following description and the appended claims.

Brief description of the drawings

The invention will now be described in more detail with reference to the appended drawings in which:

Fig. 1 is a perspective view showing a press with a press frame module according the invention.

Fig. 2 is a perspective cross section along Ill-Ill in Fig. 1. Fig. 3 is a cross section in an enlarged scale showing a connecting bar inserted in a plate.

Fig. 4 is a perspective view of a press frame module according the invention. Fig. 5 is a front view of a rear plate in the press frame shown in Fig. 1.

Fig. 6 is a cross section in an enlarged scale showing a connecting bar inserted in and attached to a plate in a press frame module according to a second embodiment of the invention.

Description of preferred embodiments

A press frame module 2 according the invention comprises a front plate 4 and a rear plate 6, each having a rectangular plate opening 8 with opposing first and second sides 8a, 8b and opposing third and forth sides 8c, 8d. Spacer elements 16 are arranged along the longsides of and between the plates 4, 6, such that they are parallely arranged with aligned plate openings 8, between which a press chamber is formed. A press platen 26 is displaceable in the press chamber along the first and second opening sides 8a, 8b. Guide rails 34 are attached to the first and second side openings 8a and 8b for guiding the displaceable press platen. The press chamber is delimited in z direction by a stationary lower platen 24 and a stationary upper platen 28, between which the displaceable press platen 26 is displaceable. Press forces are transferred via the upper and lower stationary platens to the front and rear plates 4, 6 and the connecting bars 16. Hence a cage structure is formed comprising the spacer elements in form of connecting bars 16, connecting the front and rear plates 4, 6, and the guide rails 34, attached to the first and second side openings 8a and 8b for guiding the displaceable press platen.

The cage structure resists bending and shearing forces on the frame arising when pressing. This structure comprises the spacer elements in form of connecting bars 16 for maintaining stability in the x, y and z directions, the displaceable press platen 26 for maintaining stability in the x and y directions and guide rails 34 for guiding the displaceable press platen and preventing the first and second opening sides from bending. X, y and z are coordinates of a three dimensional Cartesian coordinate system as is shown in Figs. 1 , 2 and 4.

Each plate has in this embodiment two parallel rows of bores, with five bores per row. Such a bore 12 is illustrated in Fig. 3. The bores 12 are arranged along the longside of the plates. Each bore 12 is on the surface to be facing the other plate provided with a surrounding circular guide recess 14 for receiving a connecting bar 16, as is most clearly shown in Figs. 4 and 5 and as will be explained below. The number of the bores depends on the size of the press. All bores 12 have the same diameter and all recesses 14 have the same diameter and depth. The front plate 4 and the rear plate 6 are identical as regards the size and position of openings and bores. All bore surfaces are finished to achieve a smooth surface impeding formation of cracks.

The spacer elements comprise ten solid circular connecting bars 16 having a predetermined length. These bars are acting as spacers between the front and the rear plate 4, 6 as well as means for connecting the plates together.

All bars have a center part 16b with a larger diameter D₂ and end parts 16a with a smaller diameter Di . The length of the center part 16b is exactly the same for all bars in order to constitue spacers between the front plate 4 and the rear plate 6. Further the smaller diameter end 16a of all bars have the same diameter.

All the connecting bars 16 are connected to the plates in the same way. The smaller diameter ends 16a of a connecting bar 16 are inserted with a tight fit in a pair of aligned bores 12 in the front and the rear plates 4 and 6. When a smaller diameter end 16a of a bar is inserted in a bore, an end surface of the larger diameter center part 16b of said bar is abutting a recess bottom surface surrounding said bore. The recess bottom surface forms a plane surface for receiving the connecting bar 16 in a right-angled fashion. The circular recess 14 has a slightly larger diameter than the larger diameter center part 16b.

With this construction the plates will be parallely arranged at a exact fixed distance from each other with the bars in a right angle in relation to the plates. Each connecting bar 16 is attached to respective plate by means of a screw 18 with a washer 20 fastened in a corresponding threaded hole in the smaller diameter end 16a. There is a clearance 22 between the washer 20 and the plate 4 enabling the plate to be properly biased against the center part of the connecting bar 16. The plate thus abuts against a "shoulder" formed in a transition area between the central portion and the end portion of the connecting bar 16. This construction further provides for a stable, yet easily assembled attachment between connecting bars and plates.

The displaceable press platen 26 is displaceable along four roller guide rails 34, with two guide rails on each plate, attached to the first and second side opening 8a, 8b in each opening 8, respectively. Each rail 34 is carrying a carriage 32 able to glide along the rail. Each carriage 32 is in turn attached to a support block 30 at the upper corner of the platen 26 and to a vertical surface of said platen. It proves that the connecting bars in combination with the press platens provide for a proper stability in a press frame. The guide rails 34 further improves the stability.

Thanks to the roller guide rails 34 the movement of the displaceable platen 26 is achieved with a high precision.

The lower platen 24 is a press table protruding into each opening 8 at the third openings sides 8c forming a bottom surface of the press chamber. The press table is attached by means of screws 56 to axles which in turn are attached to an anvil table, which could be affected by an anvil cylinder and by means of screws along the third openings sides 8c.

The upper platen 28 is fixed in essentially the same way and protruding into each opening 8 at the forth openings sides 4d forming a top surface of the press chamber. The upper platen 28 is carrying two main cylinders 38 and an additional cylinder 36 of which only a part are visible in Fig. 2. The cylinders are acting on and carrying the displaceable platen 26.

The additional cylinder is an optional cylinder which could be used for ejection, for example. The cylinders are in communication with a high- pressure pump via the fluid power conduits 54.

As seen in Fig. 1 outer cover plates 42 are arranged between the front and the rear plate 4, 6 outside the connecting bars 12 for preventing unintentional access to the press chamber and for protection in case of bursting conduits.

Further, inner cover plates 44 are arranged between the front and the rear plate 4, 6 inside the connecting bars 16. A door 40 is arranged below the cover plate 42 for allowing access to the press chamber and other interior parts of the press in case of maintenance.

The press 1 in Fig. 1 is adapted for front feeding but with modified cover plates 42 , 44 and door 40 it is easily adapted for side feeding.

The press frame module according the invention is to be used for a press, such as the press shown in Fig. 1. This press is a hydraulic press 1 , though the press frame module 2 could be used for other types of presses, such as mechanical or eccentrical presses. The press 1 in Fig. 1 is provided with an operator display 48, an electric cabinet 46 and an inspection balcony 50. Further is shown motor parts 52 and the fluid power conduits 54. In the following a second embodiment will be described. Essentially all features disclosed in the first embodiment are also present in the second embodiment with reference numerals identifying similar or same features. Having mentioned this, the description will focus on explaining the differing features. The second embodiment differs in that each of the connecting bars 116 has frusto-conical end portions 116a, as illustrated in Fig. 6. The cross sectional area of each frusto-conical end portion 116a is decreasing towards the free end of the end portion. Furthermore, each of the bores is provided with a sleeve 117, which sleeve enables a tight fit of the frusto-conical end portion 116a in the corresponding bore 12. Each sleeve 117 has an inner wall surface with the same shape as the corresponding frusto-conical end portion 116a and an outer wall surface with the shape as the corresponding bore 12. In this embodiment the outer wall surface has the shape of a cylinder. Each end portion 116a of a connecting bar 116 is attached to respective plate by means of a screw 18 with a washer 20 fastened in a corresponding threaded blind hole in the frusto-conical end portion 116a, as illustrated in Fig. 6. There is a clearance 122 between the sleeve 117 and the central portion 116b of the connecting bar 116 enabling the center portion 116b to be properly biased against the plate 4. A "shoulder" 19 formed in a transition area between the central portion 116b and the end portion 116a of the connecting bar 16 thus abuts against the plate 4.

It is realized that except from the disclosed differing features also features disclosed in the first embodiment are present in the second embodiment. The description of the first embodiment thus in large extent also goes for the second embodiment.

A method for manufacturing a press frame module for a press comprises first forming the front and the rear plate essentially identical, wherein each plate is provided with an essentially rectangular opening with opposing first and second sides and opposing third and forth sides in a front plate and a rear plate, and perforated with several bores along each longside. Then the spacer elements are formed by cutting a solid bar, such as a solid circular bar, at a predetermined length for preparing a connecting bar for each pair of aligned bores in the front and the rear plates. Each connecting bar is turned to obtain smaller diameter ends, or frusto-conical end portions, for insertion with a tight fit in respective bores. Each bar is inserted in respective bores such that the plates are parallely arranged and attached to respective plate by means of screws screwed into blind holes in the smaller diameter ends, or end frusto-conical end portions. Optionally, sleeves having an inner wall surface with the same shape as frusto-conical end portions may be inserted in the bores before inserting a frusto-conical end portion in a corresponding bore. Stationary upper and lower platens are attached to the forth and the third side openings, respectively. Further each plate is provided with a pair of parallely arranged and opposing guide rails, and a displaceable press platen is clamped along the guide rails. This method provides for achieving a frame structure which to a great extent facilitates manufacturing of the separate parts as well mounting of said parts as the frame structure comprises few different structural elements without need of welding.

As the press frame module contains few structural parts it is extremely cost effective to manufacture and simple to assemble. No post treatment is needed.

The press frame module according the invention is also simple to customize depending on the customer's need. The front and rear plates and the connecting bars easily are adapted to different sizes of press tables and press tools without cumbersome reconstruction and machine adjustments at manufacturing of the separate module parts. Depending on the chosen size of press frame the plates are machined as regarding dimension, size of plate opening, number and dimension of bores and the connecting bars are machined as regarding length and diameters.

The person skilled in the art realizes that the present invention by no means is limited to the embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims. It will be appreciated that the described embodiment of the invention can be modified and varied by a person skilled in the art without departing from the inventive concept defined in the claims. It is realized by a person skilled in the art that features from various embodiments disclosed herein may be combined with one another in order to provide further alternative embodiments.

In a disclosed embodiments the bore is provided with a sleeve. Alternatively, a frusto-conical end portion may be directly received in a bore, i.e. without a sleeve inserted therein, which bore has the shape of the corresponding frusto-conical end portion. A frusto-conical end portion may thus be received with tight fit in a frusto-conical bore arranged in a plate.

Furthermore, an end portion, or a smaller diameter end, of a connecting bar may be attached to a plate by means of a wedgeshaped element, such as a key or cotter instead of using a screw, which is received in a transverse hole in the end portion.

Claims

1. Press frame module for a press comprising a front plate (4) and a rear plate (6) parallely arranged to each other, spacer elements (16; 116) arranged between the plates (4, 6), and a press platen (26), which is displaceable in a press chamber formed between the plates (4, 6) c h a r a c t e r i z e d in that each of the spacer elements (16; 116) is a solid connecting bar having a center portion (16b; 116b), forming a spacer, and end portions (16a; 116a), said center portion (16b; 116b) having a larger cross sectional area than each of the end portions (16a; 116a), and each of said end portions (16a; 116a) being received with a tight fit in a bore (12) arranged in a corresponding one of said plates and being attached to that plate by means of a tightening element (18).

2. Press frame module according to claim 1 , wherein said tightening element is a screw (18) screwed into a blind hole in the end portion (16b; 116b).

3. Press frame module according to any one of the preceding claims, wherein the plate thickness in an area around each of the bores (12) is larger than the length of the corresponding end portion (16b; 116b).

4. Press frame module according to any one of the preceding claims, wherein each bore (12), on the surface facing the opposite plate, has a surrounding circular recess (14) forming a plane surface for receiving a connecting bar (16; 116) in a right-angled fashion.

5. Press frame module according to any one of the preceding claims, wherein each of the end portions (16a; 116a) has a circular cross section.

6. Press frame module according to claim 5, wherein each of the end portions (16a; 116a) has the shape of a cylinder.

7. Press frame module according to any one of the claims 1 -5, wherein each of the end portions (116a) has the shape of a frusto-cone, the cross sectional area of which is decreasing towards the free end of the end portion.

8. Press frame module according to claim 7, wherein at least one of said bore in the plates is provided with a sleeve (117) inserted therein, the sleeve (117) having an inner wall surface with the same shape as the corresponding frusto-conical end portion (116a).