EP4019238A1

EP4019238A1 - High performance press machine for clay artifacts

Info

Publication number: EP4019238A1
Application number: EP21217399.1A
Authority: EP
Inventors: Silvio GIACCARDI
Original assignee: Bongioanni Macchine SpA
Current assignee: Bongioanni Macchine SpA
Priority date: 2020-12-23
Filing date: 2021-12-23
Publication date: 2022-06-29
Anticipated expiration: 2041-12-23
Also published as: EP4019238B1; EP4019238C0

Abstract

Press machine (11) for clay artifacts, in particular for the making of roof tiles, comprising: a support structure (13) comprising a base frame (15), two lateral uprights (17, 19) each having a first end (17a, 19a) associated with said base frame (15), wherein said uprights (17, 19) are distanced from each other, a cross beam (21) connected to a second end (17b, 19b) of each upright (17, 19) and distal to said base frame (15); a pressing part (23) movable in a vertical direction relative to the support structure (13) and associated with said support structure (13) between said cross beam (21) and said base frame (15), said pressing part (23) comprising first mold-holding units (29) equipped with support means for supporting a plurality of first molds, and a camshaft (31) arranged to provide said pressing part (23) with a desmodromic movement along said vertical direction relative to the support structure (13); a movable element (39) rotatably associated with the support structure (13) and proximal to said base frame (15), said movable element (39) comprising second mold-holding units (41) equipped with support means for supporting a plurality of second molds, wherein the movement of said movable element (39) is synchronized with the movement of the pressing part (23) in order to bring said second mold-holding units (41) to said first mold-holding units (29) for the making of molded objects; wherein said camshaft (31) comprises at least two cams (33) each having a plurality of cam portions defining respective pressing tracks (43) cooperating with pressing elements (47) for imparting a downward movement onto the pressing part (23) and respective lifting tracks (45) cooperating with lifting stroke elements (49) for providing the pressing part (23) with a lifting movement towards the cross beam (21).

Description

Technical Field

The present invention relates to a high performance press machine for clay artifacts, especially for clay building products, such as roof tiles and the like, and particularly to a drum press machine.

Prior Art

According to prior art, a press machine for clay building products may be of the mechanical or hydraulic type, depending on the technology employed for generating the pressing force. Forming of an artifact of the type of a clay building product takes place by means of a pressure exerted by a movable part of a press, called pressing plunger, which, by means a desmodromic cam mechanism, or a hydraulic cylinder, presses a plastic mixture of clay and water into the space defined between two molds. Due to the fact that the press machine is usually oriented with the movement of its movable part along a vertical axis, a first mold associated with the pressing plunger is referred to as upper mold, and a second mold, usually stationary during pressing, is referred to as lower mold, or counter-mold. According to prior art, the upper and lower molds are shaped so as to define therebetween a space adapted to confer the desired shape and consistency onto the molded product.
The upper mold is linked to the pressing plunger by means of an upper mold-holding unit equipped with a mold-holding plate with which the upper mold can be rigidly associated. The lower mold, instead, is linked to another movable component of the press machine, known as drum, whose purpose is to cyclically bring the lower mold under the pressing plunger, at each pressing cycle, thus ensuring continuous operation of the machinery and unloading of the manufactured artifacts.
Such drum press machines are usually driven by an electric motor and have a production rate governed by the requirements of the artifact to be molded. More particularly, rotation of the driving shaft corresponds to a downward and upward movement of the pressing plunger, more precisely of the upper mold, and a product, for example a plurality of roof tiles, is molded at each downward stroke of the pressing plunger.
Some examples of press machines currently known in the field of the making of clay artifacts are described in documents DE20306186U1 and CN102896690 (A ).
A drawback of press machines for the making of clay artifacts lies in that said press machines have a configuration such that the size of the press machine must necessarily be limited, i.e. they allow to install only a small number of molds onto the pressing plunger. This results in poor production yields and high operating costs for each molding cycle performed by the press machine.
Document US3785194A describes a transfer press machine for machining workpieces by means of a series of pistons driven by a camshaft. One of the main objects of the press machine described in this document is to independently control the pistons in order to carry out different machining operations requiring certain phase differences.
The main object of the present invention is therefore to overcome the drawbacks and limitations mentioned above, by providing a press machine for clay artifacts that allows to increase the production yields in order to obtain a larger number of molded items, for example roof tiles, with a single molding cycle.
Another object of the invention is to provide a press machine for clay artifacts that is robust and reliable and can be industrialized at affordable costs.
These and other objects are achieved with a large-sized press machine as claimed in the appended claims.

Summary of the Invention

The press machine for clay artifacts, especially for the making of clay building products, such as roof tiles and the like, according to the invention, comprises, according to a preferred embodiment, a support structure having a base frame, a pair of lateral uprights, each having a first end associated with said base frame, wherein said uprights are distanced from each other, and a cross beam connected to a second end of each upright and distal to the the base frame. Preferably, the components of the support structure form a closed loop structure, with a substantially quadrilateral shape, said components being mutually connected.
The press machine further comprises a pressing part, or pressing plunger, movable in a vertical direction relative to the support structure and associated with said support structure between the cross beam and the base frame. The pressing part in turn comprises respective first mold-holding units equipped with support means for supporting a plurality of first molds, or upper molds. The pressing part further comprises a camshaft driven in its rotational movement preferably by an electric motor of known type, in order to impart, by its rotation, a desmodromic movement onto the pressing part along a vertical direction of the support structure, more particularly adapted to impart a reciprocating movement onto the pressing part. More preferably, the camshaft is adapted to provide the pressing part with a downward movement towards the base frame and an upward movement towards the cross beam.
The pressing machine further comprises a movable element rotatably associated close to the base frame, between the pressing part and said movable element. Preferably, the movable element is mounted transversely to the support structure, with its ends associated with the lateral uprights. The movable element in turn comprises respective second mold-holding units having corresponding support means for supporting a plurality of second molds and has a rotational movement around an axis transverse to the support structure. Preferably, the movable element comprises a rotary drum for loading clay and unloading the manufactured items after pressing.
Advantageously, the movement of the movable element is synchronized with the movement of the pressing part in order to bring said second molds to said first molds for the making of molded objects, such as roof tiles and the like.
Advantageously, according to the invention, the camshaft comprises at least two cams, each having a plurality of cam portions defining respective pressing tracks and respective lifting tracks. In the illustrated embodiment, the pressing tracks cooperate with pressing elements for imparting a downward movement onto the pressing part, in order to bring the first mold-holding units to the second mold-holding units of the movable element. The lifting tracks cooperate with lifting stroke elements for providing the pressing part with an upward pulling movement, i.e. towards the cross beam of the press machine, thus bringing the first mold-holding units away from the second mold-holding units.
The cross beam further comprises support means extending inferiorly towards the pressing part of the press machine and are provided with appropriate seats adapted to receive and support the camshaft centrally to the press machine and rotatably.
Advantageously, the support means and the cross beam with which they are associated define a yoke-like arrangement for supporting, preferably centrally within the press machine, the camshaft in its rotational movement.
Preferably, the support means comprise a pair of plates extending centrally downwards from said cross beam, said plates being arranged symmetrically relative to a center plane of the support structure. Preferably, the seats adapted to receive and support the shaft comprise openings having a substantially circular shape and provided with supports in the form of bearings.
The camshaft is mounted in a direction substantially parallel to the cross beam and preferably comprises a first shaft portion and a second shaft portion that extend towards the lateral uprights on one part and on the other part, respectively, relative to the support means preferably located at the center of the cross beam.
Preferably, the two shaft portions are connected to each other by means of a connection joint, torsionally rigid, which substantially does not allow for angular displacements of a shaft portion relative to the other shaft portion, but allows for a small inclination of the rotation axes of the hubs relative to each other, and preferably also for a small axial displacement, so as to compensate possible misalignments between the two shaft portions.
Thanks to the yoke-like arrangement defined by the cross beam and the shaft supporting means it is therefore possible to increase the length of the camshaft while allowing to obtain a robust and reliable press machine.
Preferably, thanks to the yoke-like arrangement the camshaft can reach a remarkable size. By way of example, the length of the shaft may be between 3800 mm and 4100 mm.
According to a preferred embodiment of the invention, the first shaft portion and the second shaft portion each comprise at least one cam having a plurality of cam portions defining respective pressing tracks cooperating with pressing elements, and a lifting track cooperating with at least one lifting stroke element and arranged between the pressing tracks. By virtue of the fact that each shaft portion comprises respective pressing tracks and respective lifting tracks, it is possible to increase the size of the pressing part and thus of the press machine, in order to allow to introduce a higher number of first molds, or upper molds, into the press machine, in comparison with the number of molds allowed by currently known press machines. More preferably, the cams form a single body with the camshaft.
Preferably, the pressing elements comprise pressing rollers rotatably and coaxially arranged in the lower region of the pressing part, in particular in the region of the pressing part facing the base frame, between the pressing tracks and the first mold-holding units.
Preferably, the lifting stroke elements comprise lifting stroke rollers, rotatably arranged in a bridge in the upper region of the pressing part, in particular on the side facing the cross beam and closer to said cross beam when the pressing part is associated with the press machine.
Preferably, the cams having a plurality of cam portions defining the respective pressing tracks and the respective lifting tracks of the first and second shaft portion are arranged on the first and second shaft portion, symmetrically relative to a center plane of said shaft.
Advantageously, according to the configuration of the press machine according to the invention, the mold-holding unit of the pressing part is adapted to receive a variable number of first molds or upper molds depending on the size of such molds.

Brief Description of the Drawings

Some preferred embodiments of the invention will be described below by way of non-limiting examples with reference to the annexed drawings, in which:

Fig. 1 is a perspective view of a press machine according to the invention;
Fig. 2 is a front plan view of a detail of Fig.1;
Fig. 3 is a longitudinal sectional view of a detail of Fig.1;
Fig. 4 is a perspective view of a camshaft of the press machine according to the invention;
Fig. 5 is a front plan view of a detail of the camshaft of Fig. 4;
Fig. 6 is a longitudinal section along the line A-A of Fig. 5;
Fig. 7 is a longitudinal section corresponding to Fig. 7, of a detail of the camshaft of Fig.4.

Description of Some Preferred Embodiments of the Invention

Referring to Figs. 1-3, there is illustrated a preferred embodiment of the invention in which the press machine for clay artifacts, especially for the making of clay building products, such as roof tiles and the like, has been referred to as a whole with reference numeral 11.
The press machine 11 comprises a support structure 13 provided with a base frame 15, and a pair of lateral uprights 17, 19, each having a first end 17a, 19a associated with the base frame 15. The uprights 17, 19 are distanced from each other and connected to each other by means of a cross beam 21 associated with a second end 17b, 19b of each upright 17, 19. In the illustrated embodiment, the various components of the support structure 13, such as the base frame 15, the uprights 7, 19 and the cross beam 21 are mutually connected with one another by known means such as fastening brackets, screws and nuts, thereby forming an intrinsically closed structure, i.e. a substantially loop-like structure.
The press machine 11 further comprises a pressing part 23, or pressing plunger, movable in a vertical direction relative to the support structure 13 and associated with said support structure 13 between the cross beam 21 and the base frame 15. To this aim, the pressing part 23 comprises appropriate guide means for engaging with guides 25 provided on the inner vertical walls 27 of each lateral upright 17, 19.
The pressing part 23 in turn comprises respective first mold-holding units 29 equipped with support means for supporting a plurality of first molds, or upper molds (not shown).
The pressing part 23 further comprises a shaft 31 having at least two cams 33 adapted to impart, by its rotation, a desmodromic movement onto the pressing part 23 along a vertical direction of the support structure 13, more particularly adapted to impart a reciprocating movement onto the pressing part 23, namely an upward pulling movement, i.e. towards the cross beam 21, and a movement of thrust downwards, i.e. towards the base frame 15. In the illustrated embodiment, the camshaft 31 is driven in its rotational movement by an electric motor 37 of known type, from which it takes its motion by means of mechanisms known to a person skilled in the art, such as, for example, a kinematic chain comprising a belt 38 transmitting motion from the pulley of the motor 37 to the pulley 40 of the press machine 11.
The press machine 11 further comprises a movable element 39 rotatably associated close to the base frame 15 between the pressing part 23 and said movable element 39. In the illustrated embodiment, the movable element 39 is mounted transversely to the support structure 13, parallelly to the cross beam 21, with its ends attached to the lateral uprights 17, 19. The movable element 39 in turn comprises respective second mold-holding units 41 equipped with respective support means for supporting a plurality of second molds (not shown) and has a rotational movement around an axis transverse to the support structure 13. In the illustrated embodiment, the movable element 39 comprises a rotary drum, preferably a drum with six faces, each of said faces being adapted to receive a respective mold-holding unit 41.
According to the invention, the camshaft 31 of the pressing part 23 comprises at least two cams 33, each having a plurality of cam portions defining respective pressing tracks 43 and respective lifting tracks 45.
Advantageously, the pressing tracks 43 cooperate with pressing elements 47 for imparting a downward movement onto the pressing part 23 and thus a thrust onto the first mold-holding units 29 in order to bring said first mold-holding units to the second mold-holding units 41 of the movable element 39.
The lifting tracks 45 advantageously cooperate with lifting stroke elements 49 for providing the pressing part 23 with an upward pulling movement, i.e. towards the cross beam 21, thus bringing the first mold-holding units 29 away from the second mold-holding units 41.
The cross beam 21 further comprises support means 51 projecting inferiorly from the cross beam 21 and extending towards the pressing part 23 of the press machine 11, said support means being provided with appropriate seats 53 that are provided close to the end of the support means 51 facing the pressing part 23 of the press machine 11 and are adapted to receive and support the camshaft 31centrally to the press machine 11 and rotatably.
Advantageously, the support means 51 and the cross beam 21 define a yoke-like arrangement adapted to support the camshaft 31 in its rotational movement.
In the illustrated embodiment, the support means 51 comprise a pair of plates 51a, 51b extending centrally downwards from said cross beam 21.The plates 51a, 51b are arranged symmetrically relative to a center plane of said support structure 13. In other embodiments, more than one pair of support means may be provided, depending on the length of the camshaft, or in still further embodiments the support means may take different shapes and positions, while still guaranteeing robustness and stability of the press machine 11 against the forces generated during pressing.
In addition, in the illustrated embodiment, the seats 53 adapted to receive and support the camshaft 31 comprise openings having a substantially circular shape and defining respective supports 55 for bearings 28 arranged radially for supporting the camshaft 31. The camshaft 31 is supported with respect to the support structure 13 by radial bearings 28 provided in appropriate supports in the inner front walls 27 of the lateral uprights 17, 19.
In the illustrated embodiment, the camshaft 31 is mounted in a direction parallel to the cross beam 21 and comprises a first shaft portion 31a and a second shaft portion 31b coaxial to each other and extending towards the lateral uprights 17,19 on one part and on the other part, respectively, relative to the support means 51. In the illustrated embodiment, each of the plates 51a, 51b supports the first 31a and the second 31b shaft portion, respectively, by means of appropriate bearings 28.
According to an embodiment example of the invention, the camshaft 31 has a length between 3800 mm and 4100 mm. However, such length of the camshaft 31 is not mandatory. Therefore, in other embodiments, the camshaft 31 may have a different length, which may vary depending on the size and number of the molds associated with the press machine 11.
In the illustrated embodiment, the first 31a and second 31b shaft portion comprise each at least one cam 33, provided in turn with a plurality of cam portions defining respective pressing tracks 43 and a lifting track arranged between the pressing tracks 43.
In the illustrated embodiment, the plurality of cam portions defining the pressing tracks 43 and the lifting track 45 of each cam 33 are made as a single piece and form a single body with the corresponding shaft portion 31a, 31b. In other embodiments, the plurality of cam portions may be provided individually on the corresponding shaft portion 31a, 31b.
The pressing tracks 43 cooperate with pressing elements 47 for imparting a downward movement onto the pressing part 23 and therefore a thrust onto the first mold-holding units 29.
In the illustrated embodiment, the pressing elements 47 comprise pressing rollers rotatably and coaxially arranged in the lower region of the pressing part 23, in particular in the region of the pressing part 23 facing the base frame 15. The pressing rollers 47 are arranged in a radial direction between the pressing tracks 43 and the first mold-holding units 29 and are supported by radial bearings 46 that are received in supports made in the form of bearings 48 provided in the lower region of the pressing part 23. In the illustrated embodiment, there are provided four pressing rollers 47, two for each shaft portion 31a, 31b, and more particularly one for each of the pressing tracks 43. Each of the pressing rollers 47 is supported by two radial bearings 46 arranged respectively on the sides of each pressing roller 47 and directly adjacent axially.
The lifting tracks 45 cooperate with lifting stroke elements 49 for providing the pressing part 23 with an upward pulling movement, i.e. towards the cross beam 21, thus bringing the first mold-holding units 29 away from the second mold-holding units 41. In the illustrated embodiments, the lifting stroke elements 49 comprise lifting rollers rotatably arranged in a bridge 57 in the upper region of the pressing part 23, in particular on the side facing the cross beam 21 and closer to said cross beam when the pressing part 21 is associated with the press machine 11. Thanks to this configuration it is possible to guarantee lifting of the pressing part 23 along the guides 25 when the cam portions defining the lifting tracks 45 arrive at the corresponding position of rotation on the camshaft 31.
Referring to Fig. 4, the camshaft 31 in which the cams 33 form a single body with the shaft 31 is illustrated. In the illustrated embodiment, the first shaft portion 31a and the second shaft portion 31b are connected to each other by a connection joint 59, torsionally rigid, which allows for angular movements along the rotation axis and is adapted to maintain the first 31a and the second 31b shaft portion firmly connected to each other and correspondingly transmit the rotary motion imparted by the motor 37.
Referring to Figs. 5-7, a connection joint 59 is illustrated, which maintains the first shaft portion 31a and the second shaft portion 31b connected to each other. The connection joint 59 comprises two sleeves 61, 63 associated with each other by means of appropriate fastening means 65, such as, for example, fastening screws. The connection joint 59 further comprises two hubs 67, 69, each received in a respective sleeve 61, 63 and adapted to receive a respective shaft portion 31a, 31b. The hubs 67, 69 of the connection joint 59 have each a toothed portion 71, 73 extending circumferentially on the outer surface of each hub 67, 69.
The sleeves 61, 63 each comprise a corresponding toothed portion 75, 77 extending circumferentially over the inner surface of each sleeve 61, 63 and adapted to cooperate with the respective toothed portion 71, 73 provided on each of the hubs 67, 69. The toothed portions 71, 73, 75, 77 of the sleeves 61, 63 and hubs 67, 69 are defined by a plurality of teeth having a slightly rounded, or domed, profile, said teeth guaranteeing transfer of the torque between hub 67, 69 and sleeve 61, 63 while allowing both for angular movements and a move away or an approach of the two hubs 67, 69 in an axial direction, as illustrated for example in Fig. 7 showing a schematic view of the connection joint 59 in a configuration in which the axes of the two hubs 67,69 are not coincident with each other. In particular, the profile of the toothed portions 71, 73, 75, 77 is defined so as to allow for an angular movement of the two hubs 67,69, preferably until an angle of about 0,08° relative to the axis of rotation. Thanks to this configuration, the connection joint 59 allows for movements that are small but essential between the first and second shaft portion 31a, 31b. If such movements were not present, load stresses would take place, which, together with the torsional stresses exerted on the camshaft 31 would not guarantee optimal operation of the camshaft 31.
Advantageously, the hubs 67, 69 have a toothed seat 79 adapted to receive the shaft portion 31a,31b, which will be provided with corresponding engagement teeth engaging in the toothed seat 79. The engagement between the shaft portion 31a, 31b and the corresponding hubs 67, 69 preferably takes place by heat interference fit. More particularly, the hubs 67,69 are heated in an electric oven containing oil, where they expand thus allowing entry of the first and second shaft portion 31a, 31b, which have a diameter slightly larger than the inner diameter of the hubs 67, 69.
Thanks to this configuration it is possible to guarantee high levels of torque transfer between the connection joint 59 and the first and second shaft portion 31a, 31b. Furthermore, this configuration allows the first and second shaft portion 31a, 31b to behave as if they were a single drive shaft from the torsional point of view, guaranteeing optimal synchronization of the cams 33 of the camshaft 31.
According to this preferred embodiment of the invention, the camshaft 31 is driven in rotation by a single motor 37 and a corresponding kinematic transmission located at one end of said shaft. In other embodiments, each shaft portion may be driven by a corresponding, dedicated electric motor. According to further embodiments, the first 31a and second 31b shaft portion may define a camshaft 31 made as a single body.
Advantageously, the number of first molds associated with the first mold-holding unit 29 may vary depending on the size of the molds. Therefore, according to some embodiment examples, the press machine 11 may receive four large-sized molds, or a number of five or six middle-sized molds, or a number of nine small-sized molds. However, the mentioned examples are not limiting and the number of first molds will be variable.
The operation of the press machine 11 according to the invention will be described in brief below. The camshaft 31 is driven in its rotational movement by the motor 37, from which it takes its motion by means of known mechanisms, such as, for example, a pulley and a belt 38 plus a set of gears. The camshaft 31 is fixed relative to the support structure 13 in its rotational movement. Upon rotation of the camshaft 31, the cams 33 also rotate, causing sliding of the pressing part 23 into the guides 25 provided in the support structure 13. More precisely, the pressing tracks 43 cooperating with the pressing rollers 47 impart a thrust onto the first mold-holding units 29 when the part with larger width L1 of the tracks 43 comes into contact with said pressing rollers 47 during rotation of the camshaft 31. This configuration is shown with reference to Fig. 3, in which it can be seen that the pressing part 23 takes a lowered position, closer to the movable element 39 consisting of a rotary drum in the illustrated embodiment. In this position, molding of objects such as roof tiles and the like takes place by means of the first 29 and second 41 mold-holding units. When the camshaft 31 rotates by 180° relative to the configuration illustrated in Fig. 3, the cam portions defining the respective pressing tracks 43 and lifting tracks 45 lift the pressing part 23, pulling it upwards by means of the cooperation between the lifting stroke rollers 49 and the lifting tracks 45. In this position, the part with smaller width L2 of the pressing tracks 43 is in contact with the pressing rollers 47 and the part with larger width L3 of the lifting tracks 45 is in contact with the lifting stroke rollers 49. Thanks to this configuration, by means of the rotation of the camshaft 31 the pressing part 23 carries out a desmodromic movement along the guides 25, i.e. a pulling movement upwards, in particular towards the cross beam 21, and a thrust downwards, in particular towards the movable element 39.
The invention as described is susceptible to several modifications and variations falling within the same inventive principle.

Claims

A press machine (11) for clay artifacts, in particular for the making of roof tiles, comprising:
- a support structure (13) comprising a base frame (15), two lateral uprights (17, 19) each having a first end (17a, 19a) associated with said base frame (15), wherein said uprights (17, 19) are distanced from each other, a cross beam (21) connected to a second end (17b, 19b) of each upright (17, 19) and distal to said base frame (15);

- a pressing part (23) movable in a vertical direction relative to the support structure (13) and associated with said support structure (13) between said cross beam (21) and said base frame (15), said pressing part (23) comprising first mold-holding units (29) equipped with support means for supporting a plurality of first molds, and a camshaft (31) arranged to provide said pressing part (23) with a desmodromic movement along said vertical direction relative to the support structure (13);

- a movable element (39) rotatably associated with the support structure (13) and proximal to said base frame (15), said movable element (39) comprising second mold-holding units (41) equipped with support means for supporting a plurality of second molds,
wherein the movement of said movable element (39) is synchronized with the movement of the pressing part (23) in order to bring said second mold-holding units (41) to said first mold-holding units (29) for the making of molded objects;
characterized in that said camshaft (31) comprises at least two cams (33) each having a plurality of cam portions defining respective pressing tracks (43) cooperating with pressing elements (47) for imparting a downward movement onto the pressing part (23) and respective lifting tracks (45) cooperating with lifting stroke elements (49) for providing the pressing part (23) with a lifting movement towards the cross beam (21).
The press machine (11) according to claim 1, wherein said camshaft (31) is mounted in a direction parallel to said cross beam (21) and comprises a first shaft portion (31a) and a second shaft portion (31b) coaxial to each other, each having a cam (33), said cam (33) being provided with a plurality of cam portions defining a pair of pressing tracks (43) and a lifting track (45) arranged between said pair of pressing tracks (43).
The press machine (11) according to claim 1 o 2, wherein the pressing elements (47) comprise pressing rollers rotatably and coaxially arranged between the pressing tracks (43) and the first mold-holding units (29) on the side of the pressing part (23) facing the base frame (15).
The press machine (11) according to any of the preceding claims, wherein the stroke elements (49) comprise lifting stroke rollers rotatably arranged in a bridge (57) on the side of the pressing part (23) facing the cross beam (21).
The press machine (11) according to any of the preceding claims, wherein said cross beam (21) comprises support means (51) projecting from said cross beam (21) and extending towards the pressing part (23), wherein said support means (51) are provided with appropriate seats (53) adapted to receive and support said camshaft (31).
The press machine (11) according to claim 5, wherein said support means (51) and said cross beam (21) define a yoke-like arrangement for supporting the camshaft (31) in its rotational movement.
The press machine (11) according to claim 5 or 6, wherein said support means (51) comprise a pair of plates (51a, 51b) extending centrally from said cross beam (21), and wherein said plates (51a, 51b) are arranged symmetrically relative to a center plane of said support structure (13).
The press machine (11) according to any of the preceding claims, wherein the support structure comprised guides (25) provided in the inner front walls (27) of each upright (17, 19), in which guides the pressing part (23) slides as a result of the desmodromic downward and upward movement imparted by the rotation of the camshaft (31) in cooperation with the pressing elements (47) and the stroke elements (49).
The press machine (11) according to any of the preceding claims, wherein the camshaft (31) has a length between 3800 mm and 4100 mm.
The press machine (11) according to any of the preceding claims, wherein the first mold-holding units (29) of the pressing part (23) are adapted to receive a variable number of first molds.
The press machine (11) according to claim 10, wherein the first mold-holding units (29) of the pressing part (23) are adapted to receive four large-sized molds, or five or six middle-sized molds, or nine small-sized molds.
The press machine (11) according to any of claims 2 to 11, wherein the first shaft portion (31a) and the second shaft portion (31b) are connected to each other by a connection joint (59), torsionally rigid, which allows for angular movements along the rotation axis and is adapted to maintain the first (31a) and the second (31b) shaft portion firmly connected to each other and correspondingly transmit the rotary motion imparted by a motor (37).
Press machine (11) according to claim 12, wherein the connection joint comprises at least one sleeve (61,63) in which two hubs (67, 69) adapted to receive a respective shaft portion (31a, 31b) are housed, and wherein the at least one sleeve (61,63) and the hubs (67, 69) comprise toothed portions (71, 73; 75, 77) complementary to each other for mutual engagement of the at least one sleeve (61, 63) with said hubs (67, 69).
Press machine (11) according to claim 13, wherein the toothed portions (71, 73; 75, 77) of the at least one sleeve (61, 63) and of the hubs (67, 69) are defined by a plurality of teeth having a slightly rounded profile in order to guarantee transfer of the torque between hubs (67, 69) and sleeve (61, 63) and allow both for angular movements and a move away or an approach of the two hubs (67, 69) in an axial direction.
Press machine (11) according to claim 13 or 14, wherein the hubs (67, 69) have a toothed seat (79) adapted to receive a corresponding shaft portion (31a,31b) provided with engagement teeth engaging in the toothed seat (79).