Machine for the semi-automatic screen-printing of foams

Abstract

The present invention relates to a semi-automatic screen-printing machine (1) specially designed to print simultaneously, using the screen-printing technique, on the transverse and longitudinal faces of a plurality of parallelepiped-shaped polyurethane foams (8). This technological breakthrough aims to meet the increasing needs of companies in terms of the customisation of foam products, in particular polyurethane, by offering the possibility of incorporating patterns, images or texts on these complex surfaces. The semi-automatic screen-printing machine (1) of the present invention is characterised in that it comprises a double screen-printing station (7) for printing on longitudinal faces of the foams (8), a double screen-printing station (2) for printing on transverse faces of the foams (8), a tilting belt conveyor (3), a telescopic belt conveyor (4) and a simple belt conveyor (6).

Description

[0001] Semi-automatic foam screen printing machine

[0002] Description

[0003] TECHNOLOGICAL FIELD:

[0004] The invention relates to the field of printing devices and specifically aims to print images and text on polyurethane foams. More specifically, it relates to a semi-automatic screen printing machine capable of printing on the horizontal and vertical faces of a polyurethane foam having a parallelepiped shape.

[0005] PRIOR STATE OF THE ART:

[0006] Foam printing is a versatile process that allows polyurethane foam products to be customized with specific patterns, images, text, and logos. This can be used for branding purposes to strengthen a company's or brand's identity, or to add labels, compliance information, or decorative designs to the mattress surface.

[0007] There are several techniques for printing on foams, for example: Digital printing, which is a modern method that allows images created digitally on a computer to be printed directly onto the foam by a special digital foam printer to deposit ink directly onto the foam, layer by layer. Then the ink is usually dried using heat or UV exposures so that it adheres properly to the foam. For example, Chinese patent document CN213831003 describes a high-definition foam printing device. The device is designed to print on foam boards of different thicknesses, such as EPE, PU, ​​EPS, and EVA foam materials. It addresses the challenge of achieving single-sided printing on foam boards that may have different thicknesses. Key features and components of the high-definition foam printing device include:

[0008] - Material Feed Unit: This unit is responsible for feeding the foam boards into the printing process.

[0009] - Processing Device: The processing device is used to improve the surface tension of the foam boards, making them suitable for high-quality printing.

[0010] - Inkjet printing device: This device performs the actual printing on the foam boards.

[0011] - Material Collection Device: This unit collects the printed foam panels.

[0012] - Transmission platform vertical height adjustment mechanism that allows the vertical height of the transmission platform to be adjusted to ensure it can accommodate foam boards of different thicknesses.

[0013] - Drive Platform (6): The drive platform consists of a motor, a transmission chain, a drive drum and a conveyor belt, which help to advance the foam panels through the printing process.

[0014] Although the high-definition foam printing system described in the Chinese patent has some drawbacks that are worth considering, the main drawbacks include the high cost of foam printing. It requires the use of special printers designed to work with this type of material. These printers can be expensive to acquire and maintain, which can represent a significant financial investment for companies, not to mention that before being printed, the foam must undergo a treatment to improve its surface tension. This treatment requires additional equipment and preparation operations, which increases the complexity of the production process. Thus, foam printing, especially when carried out in high definition, can take considerably longer than the manufacturing and cutting of the foam itself.This means that the printing process can become a bottleneck in overall production, causing additional delays in the delivery of finished products. Adjusting the vertical height of the transmission platform to accommodate different foam thicknesses can be a delicate operation, requiring precise management. Errors in this process can lead to printing problems and delays.

[0015] Another prior art technique for printing foams is screen printing. This method involves using a screen as a stencil to transfer ink to the foam. The first step is to prepare a fabric or mesh screen stretched over a frame. Next, a stencil is created by applying a photosensitive coating to the screen, followed by exposing the screen to light with the desired pattern. The ink is deposited onto the screen, and then a squeegee is used to force the ink through the open areas of the stencil (where the light has hardened the photosensitive emulsion), transferring it to the foam below. Finally, the printed foam is dried to ensure strong ink adhesion.

[0016] A prior art document bearing the number US5176076 A describes a screen printing machine that performs screen printing by moving a squeegee in contact with a screen to force a printing paste through a printing pattern formed on the screen. The squeegee is held by a squeegee head. The squeegee head includes a support member for supporting the squeegee so as to move it up and down, and at least one movable member that pivotally supports the head and is movable together with the support member. When the squeegee is to be replaced, only the support member is angularly movable relative to the movable member so as to provide sufficient space above the screen to facilitate replacement of the squeegee.

[0017] However, recently, in the type of screen printing for printing a pattern, on a small scale such as an electronic circuit, and which has linear motion guides employing ball bearings which are used as guides for the squeegee head. Such a linear motion type guide driven by an electric motor and a ball screw as a driving device to alternately move the squeegee head. To date, mattress foam manufacturing lines use a manual screen printing method due to the large size of the foams and which has several disadvantages in a production line, including:

[0018] - Dirt and waste: During manual printing, there may be ink splashes or spills on the work table or floor. These ink residues can stain the foams that pass over the work table, resulting in inferior finished products. In addition, these ink stains can cause hygiene problems in the workplace and require frequent cleaning, which can lead to lost time and productivity.

[0019] - Production waste: Using manual screen printing can lead to an increased number of defective products due to human errors such as misprints, mismatches, and color errors. These defective products become costly industrial waste that must be disposed of properly.

[0020] - Operator health risks: Manual screen printing operators are often exposed to inks, solvents, and chemicals used in the printing process. Prolonged exposure to these substances can have adverse effects on workers' health, including respiratory problems, skin irritation, and long-term health risks. While appropriate safety measures, such as wearing personal protective equipment, are essential, there is always a residual risk to operator health.

[0021] -Production speed limitations: Manual screen printing is generally slower than automated printing methods. This can limit the factory's production capacity, leading to delays in delivering finished products to customers.

[0022] - Variable print quality: Manual printing can also result in variations in print quality depending on the operator's skill. Differences in pressure, speed, and ink application can lead to inconsistent results.

[0023] To mitigate these drawbacks, many companies are opting for automated or semi-automated screen printing machines, which allow for faster production, consistent print quality and reduced health risks for workers.

[0024] For this purpose, the present invention proposes a semi-automated screen printing machine which makes it possible to mark prints on the horizontal and vertical faces of a plurality of foams simultaneously.

[0025] STATEMENT OF THE INVENTION

[0026] The present invention aims to simultaneously solve the problems mentioned above by introducing an innovative solution in the form of a screen printing machine specially designed to print simultaneously on the transverse and longitudinal faces of several foams having parallelepiped shapes. This technological advance aims to meet the growing needs of companies in terms of customization of foam products, by offering the possibility of incorporating patterns, images or texts on these complex surfaces.

[0027] Until now, printing on foam surfaces has presented major challenges in terms of technical complexity and production efficiency. Traditional manual printing methods were often limited in terms of print quality, accuracy, and flexibility to meet customization needs.

[0028] Thus, printing on both parallelepiped faces of foams presents significant complexities in the screen printing process. Due to the three-dimensional nature of parallelepiped shapes, ensuring accurate and consistent printing on both faces can pose major technical challenges. The need to maintain precise alignment of the printing screen with the foam surfaces throughout the process adds an additional dimension of complexity.

[0029] Additionally, ensuring uniform ink distribution on both sides is a significant challenge. Since foam surfaces can have varying textures or irregular surface characteristics, ensuring consistent ink application on these surfaces can require precise adjustments to the printing process. Furthermore, efficient foam management during the printing process can pose logistical challenges, as handling parallelepiped shapes may require specific support and positioning to ensure accurate, high-quality prints.

[0030] By overcoming these complexities, the screen printing machine presented demonstrates a remarkable ability to precisely handle the printing requirements on both parallelepiped sides of foams. With its sophisticated mechanism and innovative features, this machine effectively addresses the challenges of customizing foam products, thus providing industries with an advanced and reliable solution to meet the growing market demands for customization.

[0031] By offering the ability to print patterns, images, or text on parallelepiped foams, this machine opens up new opportunities for businesses. It allows them to create unique products, strengthen their brand, and meet the specific needs of their customers. Furthermore, by automating the printing process, it helps increase production efficiency, thus reducing costs and delivery times.

[0032] The semi-automatic screen printing machine (1) which is the subject of the present invention is characterized in that it comprises

[0033] - Double horizontal screen printing station (7);

[0034] - Double vertical screen printing station (2);

[0035] - An inclined belt conveyor (3);

[0036] - A telescopic belt conveyor (4);

[0037] - A single belt conveyor (6);

[0038] In the present invention, a vertical screen printing station is defined by a screen printing station specially designed for printing on the longitudinal face of foams 8 having parallelepiped shapes by applying a printing method using a screen with patterns or designs to transfer ink onto the surface of the foam and the foam is positioned so as to expose its longitudinal face. On the other hand, a horizontal screen printing station is designed for printing on the transverse faces of the foams. In this case, the foam is positioned so as to expose one of its transverse faces under the screen printing screen is applied against this surface, and the printing process is similar to that of the vertical station, where the ink is transferred through the open areas of the screen to create the desired pattern on the transverse face of the foam.

[0039] The screen printing process of the foams (8) begins with the deposit of the foams on the single belt conveyor (6). These foams are then conveyed under the horizontal screen printing station (7), which performs a 90° degree pivot to position the printing screen above the longitudinal faces of the foams (8). Once this screen printing operation is completed, the foams are transferred to a telescopic belt conveyor (4), which in turn transmits them to the tilting belt conveyor (3). When the foams are received by the tilting conveyor (3) a holding bar (31) clamps the foams (8) before the tilting conveyor is inclined. Once the tilting conveyor has performed a 90° rotation, the vertical screen printing station performs a rotation to position the printing screen above the foams (8).

[0040] This complex process allows for high-precision printing on multiple foams simultaneously, optimizing the accessibility of vertical and horizontal screen printing stations. The foams are thus subjected to screen printing operations on their longitudinal and transverse faces, allowing the personalization of foam products in an efficient and controlled manner.

[0041] BRIEF DESCRIPTION OF THE DRAWINGS:

[0042] The semi-automatic screen printing machine which is the subject of the present invention will be described in more detail by way of non-limiting example, in the attached drawings, in which

[0043] - Figure 1: Represents a perspective view of the screen printing machine comprising a double horizontal screen printing station, double vertical screen printing station; an inclining belt conveyor; a telescopic belt conveyor; a single belt conveyor; - Figure 2: Represents a perspective view of the horizontal screen printing station;

[0044] - Figure 3: Represents a perspective view of the vertical movement mechanism of the horizontal screen printing station;

[0045] - Figure 4: Represents a perspective view of the squeegee and the counter squeegee

[0046] - Figure 5: Represents a perspective view of the print screen

[0047] - Figure 6: shows a perspective view of the horizontal movement mechanism of the scrapers and counter scrapers

[0048] - Figure 7: Represents a perspective view of the supports holding the printing screen.

[0049] - Figure 8: represents a perspective view of the simple conveyor;

[0050] - Figure 9: represents a perspective view of the tilting conveyor;

[0051] - Figure 10: represents a perspective view of the conveyor tilting mechanism;

[0052] - Figure 11: Represents a perspective view of the mechanism for holding the foams in the tilting conveyor;

[0053] - Figure 12: Represents a perspective view of the telescopic conveyor;

[0054] - Figure 13: Represents a perspective view of the telescopic mechanism of the conveyor;

[0055] - Figure 14: Represents a perspective view of the pivoting mechanism of the screen printing stations;

[0056] - Figure 15: drive mechanism of the trays of the screen printing pivoting mechanism;

[0057] Equivalent elements shown in the different figures will bear the same numerical references. DETAILED DESCRIPTION OF THE INVENTION:

[0058] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, those skilled in the art will understand that the present invention may be practiced without these specific details. In other instances, well-known components and circuits have not been described in detail so as not to obscure the present invention.

[0059] Unless specifically indicated otherwise, as will be apparent from the following discussions, it is understood that throughout the description, discussions using terms such as "mechanism", "equipment", or the like, refer to a mechanical component or assembly of components, or a mechanical, pneumatic, electrical or similar device, which manipulates and / or transforms movements, energy, into other forms in a similar manner.

[0060] In the description of the present embodiment, certain terms "X", "Y", "Z", "R", "wide width", "horizontal", "front-back", "right-left", "top-bottom", and the like serve only to describe the present invention and simplify the description, and therefore cannot be construed as limiting the present invention.

[0061] The embodiments below are only used to illustrate the technical solutions of the present invention, and are not limited to the above embodiments, and the specific embodiments of the present invention should not be considered as being limited to the above description, and those skilled in the art may still make modifications to the above embodiments, or make equivalent substitutions for certain technical features, and such modifications or substitutions should be considered as falling within the scope of protection of the present invention.

[0062] As already explained above, the invention relates to a screen printing machine for a plurality of foams simultaneously which will now be described in detail with reference to the figures which represent a first non-limiting example of embodiment of the invention. Figure 1 refers to a screen printing machine 1 for a multitude of foams simultaneously according to a preferred embodiment of the invention comprising: A double horizontal screen printing station 7; a double vertical screen printing station 2; an inclinable belt conveyor 3; A telescopic belt conveyor 4 and a single belt conveyor 6; the screen printing operation of the foams begins with the careful placement of the foams on the single belt conveyor, thus ensuring a smooth progression of the operations.Guided by the conveyor, the foams are then directed towards the vertical screen printing station, which rotates 90 degrees to position the printing screen precisely above the longitudinal faces of the foams (8). This configuration guarantees precise and uniform printing on all surfaces.

[0063] Once the vertical screen printing process is complete, the foams are moved to the telescopic belt conveyor, which then passes them to the tilting belt conveyor. At this point, a clamping mechanism integrated into the tilting conveyor holds the foams firmly in place, ensuring optimum stability during the screen printing operation. The subsequent 90-degree tilt of the conveyor allows the horizontal screen printing stations to take over the printing process, precisely positioning the printing screen above the foams (8) for perfect printing on the transverse surfaces.

[0064] The horizontal and vertical screen printing station are similar and include the same mechanisms. Subsequently, the description will detail the horizontal screen printing station and the same reasoning will apply to the vertical screen printing station.

[0065] As shown in Figure 3, the screen printing station mechanism comprises a double vertical actuation mechanism (74) which allows the vertical movement of the actuating mechanism of the squeegees and the printing tables in the "Z" direction. After the end of the printing cycle, the carriage (743) rises to the high position on a main beam (722) secured to the guide means 742 for the back and forth movements of said carriage (743) along vertical rails (740) fixed on the frame (741). In one embodiment of the invention, the guide means 742 consist of wheels which move along the rails (740). This carriage (743) is driven in translation by a chain (745) actuated by a geared motor (744) connected to a motor shaft equipped with two motor pinions at its upper end and two free return pinions at its lower end.

[0066] Figure 6 is a schematic view showing the construction of the drive mechanism 75 for driving the squeegees 721 in the "Y" direction relative to the printing screen, in a first embodiment of the present invention, and Figure 4 is a schematic view showing the driven portion 72. The drive mechanism 75 includes a drive motor 751 rotatably connected to drive the rotation of a speed reducer, in order to rotate a pulley 750 and move the belt 751 in the "Y" direction of the guide rail or in the longitudinal direction of the printing table. In the present embodiment, the two squeegees 72 and 72' when driven, move horizontally which perform a reciprocating movement in a longitudinal direction of the squeegee and the counter squeegee.

[0067] The belt conveyor shown in Figure 8 comprises a support table 60 consisting of a rectangular frame formed by transverse beams and longitudinal beams, on the end faces of which there are rollers 64, 64' in the direction of transport driven by a geared motor 63 and an endless belt 62 guided around these rollers 64 / 64', the positioning sheet 61 makes it possible to make the printing zone in each foam coincide with the imprints of the printing screen.

[0068] Referring to Figures 15 and 16, the vertical displacement mechanism (74) is mounted on a rotating table (76) about a vertical axis "R". This pivoting mechanism (76) comprises the following elements:

[0069] - Swivel plate (761) designed to rotate around the vertical axis of rotation "R" and having a circular shape whose first upper face is mounted by bolting with two vertical displacement mechanisms (74) symmetrical with respect to the median plane perpendicular to the swivel plate (761) while the second lower surface is bolted to an idler pinion (762) connected to a motor pinion (766) by a chain.

[0070] - Motor pinion (766) is engaged with the idler pinion (762) by a chain responsible for transmitting motion from the reducer (767) coupled to the electric motor (764). - Rollers (765) for guiding the platter which are angularly spaced under the platter. These rollers provide stable support and prevent excessive slippage or vibration during rotation.

[0071] According to one embodiment, the device for driving the horizontal squeegees on the printing screen along the Y axis comprises:

[0072] - A carriage 72 comprising means for supporting the scrapers 720 and the counter scraper 727, constituted by carrying jacks 723 mounted on a main beam 722 secured to means for guiding the forward and return movements of said carriage in rails fixed to a frame of the device 75,

[0073] - A toothed belt 753 driven by a driving toothed pulley 750 at one end and an idler pulley 752 at the other end.

[0074] Figure 5 shows the printing table (71), which is mounted normally horizontal and vertically movable relative to the (74), through the vertical drive mechanism (74) which allows the entire printing table (71) to be raised or lowered, by sliding the support means 743 on the rails 740. It comprises: The screen printing screen 710 being mounted on a frame 71 1, the movements above the screen allow, among other things, to move the screen away from the printing table each time a foam to be printed is brought in and the counter-squeegee 727 is used to collect the excess ink carried by the squeegee 721 at each printing pass, to bring it back in the opposite direction, spreading it on the screen, without pressure this time, or when they are not interested in adapting the movement stroke of the squeegee and / or the counter-squeegee to the useful length of the screen, on supports of a length shorter than that of the printing table.

[0075] The screen printing screen assembly takes advantage of these movements to allow for efficient spacing of the printing table. This function is crucial when introducing new inks for printing. In this way, the screen can be moved smoothly, providing easy access for loading new inks while ensuring optimal print quality. On the other hand, the fundamental role of the counter-squeegee is reflected in its ability to recover excess ink. By doing so, it gently returns the excess to the screen, avoiding excessive pressure that could compromise print quality. This precise and delicate action ensures a smooth and efficient printing process, contributing to final results of great finesse and precision.

[0076] Furthermore, Figure 7 highlights the details of the means (712) for fixing the screen (710) to the frame (71 1 ) by means of transversely arranged side panels. These side panels, designed to ensure optimum stability, can be moved through the use of mechanical jacks (713). The latter play an essential role in ensuring precise adjustment of the position of the screen relative to the frame, thus allowing customized positioning according to the specific needs of the application. Thanks to this sophisticated fixing system, the screen can be securely held in place while providing the necessary flexibility for possible subsequent adjustments or modifications.

[0077] As can be seen in Figure 4, the squeegee is made up of a pair of blades made of flexible material 721 opposite and secured to a wooden plate 726 which envelops its upper edge. The squeegee and the counter-squeegee are both mounted under the same carriage truly secured to the carriage 723 guided longitudinally relative to the screen. They are connected to it separately by means of support means constituted by carrying jacks 723 which are permanently installed on hollow profiles 722, said carrying jacks 723 can themselves and independently of each other rise or lower relative to the hollow profiles 722 which are common to them.On the other hand, it is between the scraper and the counter scraper 721 that the inclination adjustment means 725 are provided, intermediate between the main part of each of the arms on which the corresponding scraper is fixed and its end plates linked with the main beam, the only one truly integral with the carriage guided in the rails of the upper frame.

[0078] According to one embodiment of the invention and referring to figures 12 and 13, the conveyor 4 comprises: a first drive pulley 42 fixed to the right end of the chassis 40 and driven by a geared motor 44; an idler pulley 43 at the other end and a telescopic mechanism 41 composed of a jack 414 arranged in a cavity at the lower part of the belt conveyor 4, and the first end of which is fixedly installed on the transverse beam 415 of the frame 40 and the second movable end of the jack 414 is mounted on beam 41 1 free in longitudinal translation relative to the frame 40 and guided on the rail 410. Said jack 414 is actuated to stretch, the central frame 41 1 to stretch the entire conveyor belt synchronously so that the belt conveyor 4 is stretched.

[0079] Referring to figures 9, 10 and 11, the rotary conveyor 3 comprises:

[0080] - A first drive pulley 35 fixed to the right end of the chassis 30 and driven by a geared motor 36;

[0081] - A 34 idler pulley at the other end

[0082] - A mechanism for holding the foams during the rotation cycle is composed of two cylinders, 310 and 312, perpendicular to the longitudinal direction of the rotary conveyor 3. These cylinders are fixed on one side to the frame 30 and on the other side to a movable bar, 311, which holds the foams in place during the rotation and printing phase.

[0083] - A pivoting mechanism 33 of the conveyor 42 relative to the chassis 40 comprising a motor 33 coupled to a speed reducer 331 which comprises two output shafts, the axes of which are perpendicular to the axis of the motor 333. The two outputs of the reducer are connected to two cranks 330, which are opposite and symmetrical relative to the longitudinal median plane of the motor 33.

[0084] Said cranks 330 have two ends. The first end is connected to the output shaft of the reducer 331, while the second end is assembled with the connecting rod 332. This connecting rod is provided with two joints which allow rotation, thus allowing the connecting rod to follow the movement of the crank 330 while transmitting the force to an axis fixed transversely to the edges of the conveyor frame. This allows the pivoting of the conveyor relative to the frame.

[0085] The screen printing machine 1 comprises a double vertical screen printing station 2 for printing on the transverse faces of the foams 8, which is similar to the horizontal screen printing station 7 previously described, also comprising a vertical actuating mechanism equipped with a lifting platform allowing vertical movement of the printing tables mounted on a turntable, pivoting about a vertical axis "R". This pivoting unit comprises a pivoting platen designed to rotate about the vertical rotation axis "R". The first upper face of the platen is fixed by bolting to two vertical displacement mechanisms symmetrical with respect to the median plane perpendicular to the pivoting platen, while the second lower surface is connected to an idler gear, which in turn is connected to a motor sprocket by a chain.

[0086] The motor pinion is connected to the idler pinion by a chain, ensuring smooth transmission of motion from the gear unit coupled to the electric motor. Guide rollers, conveniently spaced beneath the turntable, provide stable support, preventing any slippage or unwanted vibration during rotation.

[0087] To ensure the longitudinal movement of the squeegees of the vertical screen printing station relative to the printing screen along the X axis, a transmission device is put in place, comprising a toothed belt driven by a toothed driving pulley at one end and an idler return pulley at the other end.

[0088] Although the invention has been described with reference to an exemplary embodiment, those skilled in the art should understand that various modifications may be made and equivalents may be substituted for the elements of the invention without departing from the scope thereof. Furthermore, numerous modifications may be made to adapt a particular situation or substance to the teachings of the invention without departing from its scope. Therefore, it is important that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention include all embodiments falling within the scope of the distributed claims. Furthermore, unless specifically indicated, the use of the terms first, second, etc.does not denote any order or importance, but rather serves to distinguish one element from another.

Claims

Claim 1. A screen printing machine (1) which prints by applying ink to a plurality of polyurethane foams (8) having a parallelepiped shape, characterized by: - A double horizontal screen printing station (7) for printing on longitudinal faces of the foams 8, provided with: two vertical displacement mechanisms (74) of the printing tables mounted on a rotary plate (761) and arranged symmetrically with respect to its vertical median plane (P) and a horizontal drive mechanism 75 of the squeegee supports 72 along the Y axis in the printing table. - Double vertical screen printing station (2) for printing on transverse faces of the foams 8, provided with: two mechanisms for vertical movement of the printing tables mounted on a rotary plate and arranged symmetrically with respect to its vertical median plane (P) and a mechanism for horizontal drive of the squeegees along the X axis in the printing table. - An inclined belt conveyor (3) equipped with a pivoting system 33 of the conveyor (42) relative to the chassis (40) and a foam holding mechanism (31 b) during the rotation cycle of the foams (8). - A telescopic belt conveyor (4) which allows the movement of the foams (8) from the single belt conveyor 6 to the tilting conveyor (3).

2. A screen printing machine (1) according to claim 1 characterized in that the printing table comprises: a screen printing screen (710) mounted on a frame (71 1); at least one carriage (724) guided in translation along the Y axis and carrying jacks (723) which can themselves and independently of each other raise or lower a squeegee (720) and / or a counter-squeegee (727) consisting of a pair of inclined, opposite and integral flexible material blades (721) with wooden plates (726) which envelop the upper edge of the squeegee and the counter-squeegee; 3. A screen printing machine (1) according to claim 2 characterized in that the pivoting conveyor 3 comprises: - A pivoting system (33) provided with a motor 333 coupled to a speed reducer (331) having two output shafts coupled to a first end of two cranks (330), while the second end of said cranks 330 are assembled with the ball joints of the connecting rods (332) which make it possible to follow the movement of the crank (330) and cause the pivoting of the conveyor (32) relative to the chassis (30). -A mechanism for holding the foams during the rotation cycle is composed of two cylinders, (310) and (312), perpendicular to the longitudinal direction of the rotating conveyor (3). These cylinders are fixed on one side to the frame (30) and on the other side to a movable bar (311), which holds the foams (8) in place during the rotation and printing phase.

4. A screen printing machine (1) according to claim 3 characterized in that the conveyor (4) comprises: a first drive pulley (42 fixed to the right end of the frame (40) and driven by a geared motor (44); an idle return pulley (43) at the other end and a telescopic mechanism (41) composed of a jack (414) arranged in a cavity at the lower part of the belt conveyor (4), and the first end of which is fixedly installed on the transverse beam (415) of the frame (40) and the second movable end of the jack (414) is mounted on beam 41 1 free in longitudinal translation and guided on the rail (410).

5. A screen printing machine according to claim 4 characterized in that the vertical displacement mechanism (74) along the Z axis is mounted on a rotating table (76 comprising: -A swivel plate (761) designed to rotate around the vertical rotation axis "R" having a circular shape whose first upper face is bolted with at least vertical displacement mechanisms (74), while the second lower surface is bolted to an idler gear (762) driven by a motor gear (766) and a transmission chain extending from the reducer (767) coupled to the electric motor (764).

6. A screen printing machine according to claim 5 characterized in that the device for driving the squeegees horizontally on the printing screen along the Y axis comprises: - A carriage (72) comprising means for supporting the scrapers (720) and counter scrapers (727) consisting of supporting jacks (723) mounted on a main beam (722) secured to means for guiding the forward and return movements of said carriage in rails fixed to a frame of the device (75), - A toothed belt 753 driven by a driving toothed pulley (750) at one end and an idler pulley (752) at the other end.

7. A screen printing machine according to claim 6 characterized in that vertical screen printing station 2 comprises a vertical actuation mechanism (74) for the printing tables and the squeegees provided with: - a carriage (743) which goes up and down on a main beam (741) secured to guide means (742) along vertical rails (740) which fit a main beam (741) - a translational drive mechanism for the carriage (743) provided with a chain (745) actuated by a geared motor (744) connected to a motor shaft equipped with two motor pinions at its upper end and two free return pinions at its lower end.

8. A screen printing machine according to claim 6, characterized in that the vertical screen printing station (2) for printing on the transverse faces of the foams 8 is similar to the vertical screen printing station (7) comprising: a mechanism for vertically actuating the printing tables and the squeegees and a device for horizontally driving the squeegees on the printing screen along the X axis.

9. A screen printing machine according to claim 5, characterized in that the pivoting plate (761) is guided by guide rollers (765) of the plate guide, spaced angularly under the plate.

Images