EP0128912B1 - Hydraulic, pneumatic, pneumatic/hydraulic or combined pneumatic/explosion press - Google Patents

Abstract

Press for manufacturing molded or pressed products, comprising a press tool (3) fixed at one end of a moving cylinder (2). Said moving cylinder (2) is coaxially mounted inside a fixed guiding cylinder (4) fixed and coaxially suspended inside a cylinder (5) forming the outer envelope of the press. The press has a moving wall (8) defining a first variable volume chamber, eight hydraulic jacks (11a-11h) with free differential pistons (12a-12h) arranged in crown about the central cylinder (2). The outer envelope (5) comprises a widening (23) provided with at least a bore (44) wherein are arranged explosion means to cause the displacement of the press tool (3) when the press is used as a combined pneumatic/explosion press. The press has reduced overall dimensions, and may be adapted to the manufacture of different articles at various working rates by simple and fast modifications.

Description

The present invention relates to a press with hydraulic, pneumatic, pneumatic / hydraulic or pneumatic / explosion combined operation used in particular for manufacturing products by compacting, sintering, pressing, shaping, stamping or embossing.

We already know many presses, hydraulic, pneumatic. However, these presses generally presented a significant bulk. For example, in terms of height, a conventional press of the same strength should be equipped with a plunger sliding in a hydraulic cylinder eight times longer than each of eight hydraulic cylinders located next to each other in the proposed press. The disadvantage is even greater with regard to the periphery of conventional construction. In the case of American patent - US Patent No. 3,320,740 described below, it can be seen that the circumference of a conventional press operating as an explosion press with a much lower force, is larger than the periphery of the new press performing all three functions, notably the hydraulic, pneumatic and combined explosion functions. In addition, if it was desired during the manufacture of the product to have several successive pressure levels, it was necessary to provide a relatively expensive and complex device for programming these pneumatic or hydraulic presses.

While the use of an explosion press for the production of metal products, for example, was simply mentioned in the book “Meyers Handbuch über die Technik published by Bibliographisches Institut - Mannheim (page 286), it is described in all its details in the aforementioned US patent. Without intending to underestimate the solution proposed in the said patent, it must be noted that, despite the larger bulk, it does not have sufficient power to perform the work which requires a higher force, with automatic adjustment. force and impact depth, sufficient and adjustable air compression not dependent on a coil spring of limited force etc. Indeed, it does not solve the main problem posed by the use of an explosion press for the production of pressed, stamped or shaped metal products concerning a precise dosage of the amount of explosive or the force of the explosion necessary to accomplish a specific job, in very short and regular time intervals.

The object of the present invention is to propose a press which can be used as a hydraulic press, a pneumatic press or a combined pneumatic / explosion press, having a small footprint and the operation of which can be automated very simply. In addition, with the press of the invention, it is possible to obtain several levels of pressure during a work cycle, by a positive control of the pressure exerted on the tool of the press, in particular when it is used as hydraulic press.

To this end, the invention which is defined in claim 1 relates to a press in particular used for manufacturing products by compacting, sintering, pressing, shaping, stamping or embossing.

According to one embodiment of the invention, the mobile cylinder of the press is mounted coaxially inside a fixed guide cylinder, fixed in a suspended manner coaxially inside a cylinder forming the outer casing of the press, this fixed guide cylinder and the cylinder forming the outer casing being fixed by their respective upper flaring on a platform for supporting the press.

According to another embodiment of the invention, the central movable cylinder of the press comprises a narrowing on which rests a movable partition 'comprising an outer cylindrical part slidably mounted sealingly against the internal wall of the intermediate cylinder to define a first variable volume chamber filled with hydraulic fluid, and the hydraulic means of the press comprising a plurality of hydraulic cylinders arranged in a ring around the central movable cylinder, in the first variable volume chamber and passing through the movable partition, each hydraulic cylinder comprising a free differential piston defining an upper chamber and a lower chamber, the upper chamber of each cylinder being supplied with pressurized hydraulic fluid by a hydraulic fluid supply pump, and the lower chamber being in fluid communication with the first volume chamber variable. The pressurized hydraulic fluid supply pump successively supplies each hydraulic cylinder.

According to yet another embodiment of the invention, the cylinder of each cylinder comprises an extension having a reduced section in which slides in substantially sealed manner the rod of the free piston associated with the hydraulic cylinder. This extension of reduced internal section opens above the working piston to form with the end of the piston rod a second chamber with variable volume filled with a hydraulic fluid.

The press can comprise an intermediate cylinder mounted coaxially in the cylinder forming the external envelope of the press, around the hydraulic cylinders, this intermediate cylinder being fixed by its upper flare on the support platform of the press and defines with the cylinder forming the outer envelope an annular chamber containing a cooling fluid, the cylindrical part of the movable partition sliding against the internal surface of this intermediate cylinder.

The cylinder forming the outer envelope of the press may include a widening also extending towards the interior of the cylinder to define an auxiliary reservoir of cooling fluid such as water, the intermediate cylinder having a collar coming to rest on this enlargement and a cylindrical part of reduced section in contact with the extension part of the hydraulic cylinders to thus define a third chamber with variable volume. This third chamber with variable volume comprises an upper chamber defined by the movable partition, the intermediate cylinder and the narrowing thereof and a lower chamber communicating with the upper chamber through orifices formed in the narrowing of the intermediate cylinder, this lower chamber being defined by the enlargement of the cylinder forming the outer envelope, the reduced section of the intermediate cylinder and the driving piston. Advantageously, this driving piston comprises an upper cylindrical part extending in a sliding manner in the space defined between the internal wall of the enlargement of the external cylinder and the reduced section part of the intermediate cylinder.

Furthermore, the pump for supplying pressurized hydraulic fluid to the hydraulic cylinders may comprise a piston fixed to the upper end of the upper section of reduced section of the central movable cylinder of the press, this piston being actuated by a screw press, for example.

The press may include a piston fitted with seals, slidably mounted in the central movable cylinder of the press below the narrowing thereof, and a piston rod disposed inside the upper section reduced from this central cylinder and from the cylinder integral with the piston of the pump for supplying pressurized hydraulic fluid. Means for actuating this piston are connected to the upper part of the piston rod so as to cause the displacement of the rod and of the piston in the movable central cylinder, these means are advantageously a screw press, mounted on the press. screw for actuating the pressurized hydraulic fluid supply pump.

To use the press as a pneumatic / combined explosion press, the explosion means may comprise at least one cylinder formed by a bore in the enlarged part of the cylinder forming the outer casing of the press, this cylinder being provided with a jacket in which slides a piston integral with the press tool and forming a projection on the upper face of an annular part of this press tool, inlet and exhaust valves, ignition means and supplying fuel to the cylinder, and a device for supplying compressed air to each cylinder, and finally an exhaust duct formed at the top of the cylinder of these means of explosion in the enlargement of the cylinder forming the outer press cover.

The valve seats for the head of the intake valve and the head of the exhaust valve can be formed respectively at the upper end of the piston and at the upper face of the cylinder of the explosion means. Advantageously, the intake valve comprises a longitudinal bore in which the body of the cylinder exhaust valve is mounted coaxially and in a sliding manner, the rod of this exhaust valve passing through the annular part of the press tool and comprising a member forming a stop on its part projecting beyond the press tool to cause the opening of the exhaust valve after a predetermined stroke of the press tool and thus limit the stroke of this press tool.

Furthermore, the device for supplying compressed air to each cylinder can be constituted by a fresh air intake valve, disposed in an orifice in the bottom of the central movable cylinder of the press, the chamber of the central movable cylinder being in fluid communication with the piston chamber through an air intake duct.

• - la figure 1 est une vue en coupe longitudinale de la presse de l'invention utilisée comme presse hydraulique, l'outil de presse étant à son point mort haut ;
• - la figure 2 est une vue semblable à celle de la figure 1, dans laquelle l'outil de presse est à son point mort bas ;
• - la figure 3 est une vue en coupe transversale selon la ligne III-III de'la figure 1 ;
• - - les figures 4, 5, et 6 sont des vues en coupe longitudinale de la partie inférieure de la presse de l'invention fonctionnant comme une presse à explosion illustrant les différents stades de réalisation d'un produit pressé, respectivement au commencement, pendant et à la fin de la fabrication du produit pressé.

The details and advantages of the present invention will appear more clearly on reading the explanatory description which follows of several embodiments of the press of the invention, given by way of example with reference to the appended schematic drawings in which:

• - Figure 1 is a longitudinal sectional view of the press of the invention used as a hydraulic press, the press tool being at its top dead center;
• - Figure 2 is a view similar to that of Figure 1, in which the press tool is at its bottom dead center;
• - Figure 3 is a cross-sectional view along line III-III de'la Figure 1;
• - - Figures 4, 5, and 6 are views in longitudinal section of the lower part of the press of the invention operating as an explosion press illustrating the different stages of production of a pressed product, respectively at the beginning, during and at the end of the manufacture of the pressed product.

The press of the invention illustrated as a whole in FIGS. 1 and 2 is mounted on a support infrastructure via a platform 1. This press can be used alone or in combination with other devices allowing '' feeding a product below the press tool 3 in a mold for the manufacture of molded products by sintering, pressing or the like, the molds can be brought one by one below the press tool by a carousel so allow continuous manufacture of articles. Indeed, as will be described below, the operation of the press of the invention can be easily automated and programmed according to the work rates. of a molded products manufacturing unit.

Referring to Figures 1 to 3, we will describe the press of the invention and more particularly a first embodiment of this press which can operate as a hydraulic, pneumatic or hydraulic / pneumatic press.

This press comprises an outer cylinder 5 forming the envelope of the press; it is fixed in a suspended manner by an upper flaring 5a on the platform 1 by screws and nuts 68.

The press of the invention also comprises a central mobile cylinder 2 mounted to slide inside a fixed guide cylinder 4 arranged coaxially inside the cylinder 5 and fixed by its upper flare 6 on the platform 1 to by means of the nuts 68. At the lower end of the central movable cylinder 2 is fixed integrally the driving piston 64 of the press tool 3 on the flare 2b of the cylinder 2.

The press also comprises an intermediate cylinder 19 mounted coaxially with the cylinders 5, 4 and 2 and fixed by its upper flaring 20 to the platform 1 by means of the nuts 68.

The cylinder 5 forming the outer envelope comprises a first enlargement 25 also extending towards the interior of the cylinder to form an annular reservoir 26 of a cooling fluid such as water. This reservoir comprises an internal wall 31 equipped with a seal 101 to allow a sealed sliding of a cylindrical part 30 of the driving piston 64 of the press against the internal surface of the wall 31. Advantageously the external wall of the reservoir 26 includes a coolant supply pipe (not shown).

In the embodiment illustrated, the cylinder 5 of the press comprises a second lower extension 69 to allow, for example, housing a container of a mixture _'of material to be pressed (not shown).

The intermediate cylinder 19 comprises a collar 27 and a narrowing 28 resting on the enlargement 25 of the cylinder 5 forming the outer envelope by means of a seal 70. Thus, the intermediate cylinder 19 defines with the cylinder 5 an annular chamber 21 containing a coolant such as water and communicating through the passage 32 formed in the enlargement 25 of the outer cylinder 5 with the coolant reservoir 26. Furthermore, the lower part 22 of reduced section of the intermediate cylinder 19 is in contact over its entire height, and in a sliding manner, with the internal surface of the working piston 64 of the press tool 3, and in particular with the internal surface of the cylindrical part 30 of this working piston.

In addition, the press of the invention comprises eight hydraulic jacks 11a to 11 arranged in a ring, around the central movable cylinder 2 and the guide cylinder 4. These jacks are mounted suspended by their upper ends in grooves 71a to 71h from the orifices. formed in the flaring 6 of the guide cylinder 4. In addition, these hydraulic cylinders 11 a to 11 h are held in position by a stationary lower disc 18 welded to the lower end of the narrowed portion 22 of the intermediate cylinder 19 and comprising orifices to insert the lower opening end of the cylinders of each hydraulic cylinder 11a at 11h.

A movable disc 8 comprising a cylindrical part 9 is slidably mounted in the intermediate cylinder 19 and comes to rest on a narrowing 7 of the movable central cylinder 2. This movable disc 8 includes openings to allow the passage of the extension part of the jacks hydraulic 11a to 11h.

Each hydraulic cylinder 11a at 11 a.m. includes a differential free piston 12 fitted with seals 72 and comprising a piston rod 16a at 4 p.m. sliding in a substantially sealed manner in the lower extension part of each cylinder which has in particular a cross section internal conjugate to the section of the piston rod 16. The piston 12 defines at its lower part a cylinder chamber 13 with variable volume communicating with a first chamber 10 with variable volume defined above the movable disc 8 between the intermediate cylinder 19 and the guide cylinder 4, by openings 73 having for example a rectangular section and formed in the lower part of the cylinder chamber 13 of each hydraulic cylinder 11 at a level below the level of the seal 72 of the differential free pistons 12 when these are at their bottom dead center.

The press comprises a second variable-volume chamber 17, 107, defined in the extension part of each hydraulic cylinder 11a at 11 am and by the lower end of the piston rods 16a at 4 pm as well as by the stationary disc 18, this second variable volume chamber having as its bottom the upper face of the driving piston 64 of the press tool 3.

The press of the invention also comprises a third chamber with variable volume divided into two chambers, an upper chamber 23 located below the movable disc 8 between the movable cylinder 2 and the intermediate cylinder 19, and a second lower chamber 24 defined below. narrowing 28 of the intermediate cylinder 19, and between its narrowed lower part 22 and the inner wall 31 of the reservoir 26 of coolant. These two chambers 24, 23 are in fluid communication through an orifice 29 formed in the narrowing part 28 of the intermediate cylinder 19 and therefore forms the third variable volume chamber of the press of the invention.

The press also comprises a central piston 39 provided with sealing segments 40 slidably mounted in the lower part of the central movable cylinder 2, this central piston comprising a piston rod 41 slidingly disposed inside the upper part 2a of reduced section. of the central cylinder 2.

In the illustrated embodiment, the press comprises a pump 14 for feeding under pressure of a hydraulic fluid in the hydraulic cylinders 11a to 11h through an oil distributor constituted by a disc 15 disposed on the upper flare 6 of the guide cylinder 4 and comprising a single orifice for successively distributing the hydraulic fluid under pressure supplied by the pump 14 in each hydraulic cylinder 11a at 11h. This disc 15 comprises a cylindrical part 74 provided with a toothing 75 engaging with the toothing of a drive wheel 76 supported by an external cylinder 77 fixed by its lower flare on the platform 1 and supporting by its flare upper a casing 78 of the feed pump 14 fixed by nuts 79.

The pump 14 for supplying pressurized oil comprises a piston 34 provided with a seal 80 mounted to slide in leaktight manner inside the casing 78 so as to delimit a chamber 33 of hydraulic fluid under pressure. The piston 34 is supported by its lower face on a narrowing 81 of the narrowed upper part 2a of the movable central cylinder 2.

The piston 34 of the pump 14 for supplying pressurized hydraulic fluid is actuated by a lower screw press enclosed in the casing 78 and comprising a toothed wheel 35 in engagement with a drive wheel 36, a rising lead screw. 37 embedded and fixed in a central bore of the toothed wheel 35, this lead screw 37 being engaged with a threaded shaft 38 integral with the piston 34.

The toothed wheel 35 is supported by lower and upper roller bearings 82, 83. Of course, it is possible to replace the lower screw press for actuating the feed pump 14 by another suitable actuating means.

In the preferred embodiment of the invention, the press comprises an upper screw press enclosed in an upper casing 84 fixed by its lower flare 85 on the upper flare 86 of the casing 78 by screws and nuts 87. This casing 84 supports by its upper flaring 88 a cover 89 fixed by means of screws and nuts 90. The upper screw press comprises a toothed wheel 42 supported by lower and upper roller bearings 91, 92 and engaged with a toothed wheel d drive 43, a mounting lead screw 93 embedded and fixed in a central bore of the toothed wheel 42 and engaged with a threaded part of the shaft 41 of the central piston 39 of the press. This piston rod 41 passes through the cover 89 and is prevented from rotating by a guide yoke 94 by means of a nut 95, the yoke being fitted on at least two guide slides 96a, 96b secured to the cover 89. Finally, the press tool 3 comprises the driving piston 64 fitted by a central opening on the central movable cylinder 2 of the press and comprising an annular part 47 on the upper face of which is fixed or formed at least one cylinder 46 forming a piston provided on its outer surface of sealing segments 97 and slidably mounted inside a jacket 45 disposed in a bore 44 forming a cylinder produced at the lower part of the enlargement 25 of the movable outer cylinder 5.

The press tool 3 also comprises a removable tool piston 66 and fixed by studs 98 and nuts 99 on the drive piston 64. The tool piston 66 has a shape combined with the shape of the products to be manufactured.

• - La presse à vis inférieure est actionnée pour mettre sous pression le fluide hydraulique, ou l'huile contenu dans le réservoir ou chambre 33. Le distributeur ou fond 15 est mis en rotation pour alimenter successivement dans les vérins hydrauliques 11a à 11h l'huile sous pression et ainsi provoquer la descente des pistons libres 12a à 12h. Avantageusement, le volume du réservoir 33 est sensiblement égal à la somme des volumes de chaque vérin hydraulique 11a a à 11 h quand les pistons 12a à 12h sont à leur point mort bas. La descente du piston 34 de la pompe d'alimentation 14 à huile sous pression provoque un déplacement du cylindre central 2 par l'effort mécanique du piston 34 sur l'épaulement 81 du cylindre 2a.
• - La descente des pistons 12a à 12h dans les vérins hydrauliques 11a à 11h chasse le fluide contenu dans la chambre de cylindre 13 à travers les orifices 73 dans la chambre à volume variable 10. L'augmentation de pression de fluide dans cette chambre 10 provoque la descente du disque mobile 8 qui exerce ainsi une force sur le cylindre central 2 au niveau de son épaulement 7 et donc sur l'outil de presse 3.
• - La descente des pistons 12a à 12h entraîne simultanément la descente des tiges de piston 16a à 16h dans la chambre à volume variable 17, 107, provoquant ainsi une augmentation de pression du fluide hydraulique contenu dans cette chambre et donc exerçant une nouvelle pression sur la face supérieure du piston moteur 64 de l'outil de presse 3.
• - Enfin, la descente de la cloison mobile 8 provoque une augmentation de pression dans la chambre à volume variable 23 et ainsi force le fluide hydraulique contenu dans cette chambre à passer dans la chambre inférieure 24 à travers les orifices 29a, 29b pour exercer une nouvelle pression sur la partie cylindrique 30 du piston moteur 64 et donc exercer une pression sur l'outil de presse 3.

Thus, the press described above can function as a hydraulic press, the means for forming the hydraulic pressure being constituted by the feed pump 14 of a pressurized hydraulic fluid such as oil, the hydraulic cylinders 11a at 11 a.m., the first variable-volume chamber 10, 13, the second variable-volume chamber 17, 107 and the third variable-volume chamber constituted by the two chambers 23, 24. The operation of such a hydraulic press which comprises four hydraulic pressure generation units will be described below:

• - The lower screw press is actuated to pressurize the hydraulic fluid, or the oil contained in the tank or chamber 33. The distributor or base 15 is rotated to successively supply the hydraulic cylinders 11a to 11h under pressure and thus cause the free pistons 12a to descend to 12h. Advantageously, the volume of the reservoir 33 is substantially equal to the sum of the volumes of each hydraulic cylinder 11a a at 11 h when the pistons 12a at 12 h are at their bottom dead center. The descent of the piston 34 of the pressurized oil supply pump 14 causes a displacement of the central cylinder 2 by the mechanical force of the piston 34 on the shoulder 81 of the cylinder 2a.
• - The descent of the pistons 12a at 12h in the hydraulic cylinders 11a at 11h drives out the fluid contained in the cylinder chamber 13 through the orifices 73 in the variable volume chamber 10. The increase in fluid pressure in this chamber 10 causes the descent of the movable disc 8 which thus exerts a force on the central cylinder 2 at its shoulder 7 and therefore on the press tool 3.
• - The descent of the pistons 12a at 12h simultaneously causes the descent of the piston rods 16a at 16h in the variable volume chamber 17, 107, thus causing an increase in pressure of the hydraulic fluid contained in this chamber and therefore exerting a new pressure on the upper face of the driving piston 64 of the press tool 3.
• - Finally, the descent of the movable partition 8 causes an increase in pressure in the variable volume chamber 23 and thus forces the hydraulic fluid contained in this chamber to pass into the lower chamber 24 through the orifices 29a, 29b to exert a new pressure on the cylindrical part 30 of the driving piston 64 and therefore exert pressure on the press tool 3.

The intensity of oil pressure exerted successively against the head of each different piston tiel 12a at 12h is adjustable by adjusting the pressure supplied by the pressurized fluid supply pump 14, during the entire descent of the movable central cylinder 2 and therefore of the press tool 3.

Since the differential pistons descend successively one after the other, the intensity of the pressure in the first variable-volume chamber 10 is determined as a function of the ratio between the working surface of the differential piston of each hydraulic cylinder and the surface useful of the partition 8 as well as the force exerted by the piston 34 of the feed pump 14.

In addition, the volume of the intermediate chamber 23 with the movable partition 8 at its top dead center is equal to the volume of the bottom chamber 24 with the engine piston 64 at its bottom dead center. The intensity of the pressure exerted by the hydraulic fluid contained in these chambers 23 and 24 is equal to the intensity of the pressure already transmitted by the movable disc 8 on the driving piston 64 via the shoulder 7 of the cylinder mobile central 2.

Finally, the volume of the variable-volume chamber 107 when the driving piston 64 of the press tool is at its bottom dead center is equal to the volume of the chambers 17a at 5 pm of the extensions of the hydraulic jacks 11 a at 11 am.

During the successive descent of the differential pistons 12a at 12h, the force exerted by the pressurized oil contained in the chambers 17 and the variable volume chamber 107 on the driving piston 64 of the press tool is equal to the pressure resulting from the ratio between the surface of a single piston rod 16a at 16h and the useful upper surface of the bottom of the engine piston 64 of the press tool, and depends on the force produced by the oil supply pump at the given time.

FIG. 2 illustrates the position of the various elements of the press when the press tool is at its bottom dead center.

The return of the press tool to its top dead center is achieved by actuation of the lower screw press to raise the piston 34 of the feed pump 14 to its top dead center and thus cause the differential pistons 12a to rise. at 12 o'clock and the driving piston 64 at their top dead center, in synchronization with the ascent of the piston rod 41 and of the central piston 39 using the upper screw press and with the synchronized rotation of the distribution base 15 of hydraulic fluid. Indeed, this central piston 39 has always remained pressed against the lower part of the narrowing 7 of the movable central cylinder 2. For this, the threaded shaft 41 of the upper screw press or the piston rod is disengaged during the descent of the press tool 3, then clutched for raising this press tool to its top dead center.

In such a press, the sealing devices are provided only for elements such as the central piston 39, the differential pistons 12a at 12 o'clock, the internal wall 31 of the enlargement 25 of the external cylinder 5, which delimit a chamber or enclosure containing a fluid with respect to a duct, an enclosure connected to ambient air or with respect to an enclosure containing a fluid of a different nature such as cooling water.

In the press of the invention it is not necessary to provide sealing elements between the different chambers with variable volume 10, 13, 23, 24, 17, 107 since the surfaces of the pistons, movable partitions are calculated so that their ratio is identical in all the chambers containing a fluid under pressure 10, 13, 17, 23, 24, 107 and therefore in which a substantially equal pressure always prevails.

- Consequently, these tanks can even communicate with each other through small pressure equalization orifices which have absolutely no influence on the efficiency of the press. Besides, these equalization orifices make it possible to eliminate any differences in volume of the different chambers, differences in volume induced by manufacturing defects. Therefore, these equalization orifices make it possible to fill the variable volume chambers with fluid such as a hydraulic fluid under pressure by a single fluid supply orifice, and in particular to compensate for any leaks of hydraulic fluid.

• - elle est capable de fournir une force de pressage élevée par rapport à son encombrement,
• - la pression finale exercée par le piston moteur de l'outil de presse est égale à la somme des différentes pressions produites dans chaque chambre à volume variable, et. donc résulte d'une multiplication de la pression exercée par le piston 34 de la pompe d'alimentation 14 en fluide hydraulique sous pression,
• - une grande économie d'énergie,
• - une course importante de l'outil de presse par rapport à la hauteur de la presse et donc une grande capacité d'alimentation en mélange dans des moules ainsi qu'une force de pressage réglable jusqu'à l'emboutissage complet des pièces à presser,
• - cette presse peut être utilisée comme une presse hydraulique ayant un fonctionnement très souple et qui peut être facilement automatisée par programmation de la pression produite par le piston 34 de la pompe d'alimentation 14 du fluide sous pression, comme une presse hydraulique pneumatique, ou hydraulique-pneumatique et à explosion combinée comme cela sera décrit ci-dessous.

Thus, this press has the following advantages:

• - it is capable of providing a high pressing force compared to its size,
• - the final pressure exerted by the driving piston of the press tool is equal to the sum of the different pressures produced in each variable volume chamber, and. therefore results from a multiplication of the pressure exerted by the piston 34 of the pump 14 for supplying pressurized hydraulic fluid,
• - great energy savings,
• - a large stroke of the press tool relative to the height of the press and therefore a large capacity for supplying mixture into molds as well as an adjustable pressing force until the complete pressing of the parts to be pressed ,
• this press can be used as a hydraulic press having a very flexible operation and which can be easily automated by programming the pressure produced by the piston 34 of the supply pump 14 for the pressurized fluid, such as a pneumatic hydraulic press, or hydraulic-pneumatic and combined explosion as will be described below.

In addition, the replacement of the press tool is very easy, and the devices for adjusting the pressure and the working rate of such a press are very accessible.

• - réglage de la course de l'outil de presse,
• - réglage de son point de départ,
• - échangeabilité du piston outil
• - réglage de la vitesse de descente et de retour de l'outil de presse.

Therefore, this press is very easily adaptable as a function of the work rate desired for the manufacture of a particular product, this adaptation being carried out by, for example:

• - adjustment of the press tool stroke,
• - setting of its starting point,
• - exchangeability of the tool piston
• - setting the speed of descent and return of the press tool.

Will now be described with reference to Figures 4, 5 and 6, the press of the invention in its variant as an explosion press in particular used for the manufacture by stamping of metal products such as a metal sheet 100 disposed above a female matrix 108 and illustrated in FIGS. 4 to 6.

To transform the press described above into an explosion press, the pistons 46 integral with the annular ring 47 of the driving piston 64 are equipped with two inlet 48 and outlet 49 valves respectively. A valve seat 51 is formed at the upper end of the piston 46 to receive the head 52 of the intake valve 48, while a second valve seat 53 is formed in the through end of an exhaust duct 50 to receive the head 54 of the exhaust valve 49.

The intake valve 48 has a central axial bore in which the body 58 of the exhaust valve 49 is slidably mounted, the rod 56 of this exhaust valve being slidably mounted in a bore 102 forming a valve guide made in the annular part 47 of the driving piston 64. In addition, the end of this valve rod 56 is threaded and comprises a stop element 57, adjustable in position and disposed below the annular part 47 of the driving piston so as to cause the opening of the exhaust valve when the press tool has traveled a predetermined distance and therefore adjust the pressing depth obtained by this press.

The enclosure 62 of the piston 46 is connected by a fresh air intake duct 63 to the chamber of the movable central cylinder 2, and is connected with the combustion chamber 55 when the intake valve is in the open position. This combustion chamber is defined between the intake valve 48 and the exhaust valve 49 when they are applied against their respective valve seats.

This combustion chamber is equipped with fuel injection and ignition devices.

Of course, the press can comprise a single cylinder 44 or several cylinders, for example three cylinders 44a to 44c as illustrated in FIG. 3, each cylinder comprising the same elements as that described above.

In the illustrated embodiment, the tool piston 65 fixed on the driving piston 64 comprises lateral bores 103 accessible to accommodate the piston rod 56 and the abutment elements 57, and a central bore 104 communicating on the one hand, with the atmosphere and, on the other hand, through a fresh air intake valve 59 with the chamber of the movable central cylinder 2. This fresh air intake valve 59 has its valve seat 60 formed in a plate circular 61 fixed below the lower flare 2b of the central cylinder 2. The piston rod of this valve is mounted in a rod guide bore produced in the body of the tool piston 65.

Advantageously, in the embodiment shown, the tool piston 65 is constituted by a disc fixed on the driving piston 64 by the bolts or nuts 98, 99 and a second part 66 fixed by bolts 106 on the disc 65, this second part having a lower face forming the male die 67 for drawing the metal sheet 100.

The explosion press works as follows:

The operating work rate of such a press is divided into three. time: fresh air intake, compression and explosion-exhaust.

The admission of fresh air is carried out by actuation of the upper screw press of the press which raises the central piston 39 in the movable central cylinder 2 to its top dead center, and thus causes the valve to open. 59 fresh air intake and fresh air intake in the movable central cylinder 2. In addition, this rise of the piston 39 and its threaded rod 41 causes the press tool 3 to rise together and therefore pistons 46a to 46c in the cylinders 44a to 44c associated with their respective top dead center as well as the intake 48 and exhaust 49 valves. The position of the various mechanical elements during the intake phase is illustrated in FIG. 4 .

When all the mechanical elements of the press have reached their top dead center, the compression phase (Figure 5) begins with the actuation of the upper screw press to now cause the central piston 39 to descend into the movable central cylinder 2 Thus, the fresh air intake valve 59 is closed and the fresh air contained in the cylinder 2 is supplied under pressure through the fresh air intake duct 63 in the piston chamber 62 which causes the opening of the intake valve 48 and the closing of the exhaust valve 49. Thus, the air compressed by the piston 39 in the cylinder 2 is supplied to the combustion chamber 55. When the pressure in the chamber combustion has reached a predetermined value which is measured for example, a pressure gauge (not shown) the descent of the central piston 39 is automatically stopped. The compression phase is thus completed.

The fuel is then injected into the combustion chambers 55 and is ignited by the aforementioned injection and ignition devices, which will cause the explosion of the gas mixture simultaneously in the three combustion chambers 55a to 55c, in the embodiment. illustrated thus causing the closing of the intake valves 48 and the transmission of the shock to the press tool via the ring 65 and therefore the stamping of the metal sheet 100. The composition of the gas mixture contained in the combustion chamber is proportioned according to of the work to be done and therefore of the pressing and stamping force to be obtained.

When the press tool has made a predetermined stroke, the ring 65 comes into contact with the stop elements 57 mounted on the rod 56 of the exhaust valve 49 causing it to open. Thus, the burnt gases contained in the combustion chamber 55 escape through the exhaust duct 50. This position is illustrated in FIG. 6.

Furthermore, at this instant, the fuel chambers 55a to 55c are swept by the compressed air remaining contained in the central cylinder 2 below its piston 39 and in the conduits 63 for admission of fresh air. Furthermore, the cooling of the piston 39 is ensured by the admission and the discharge of the fresh air during its reciprocating movement through a channel 105 connected to the fresh air chamber 104.

Advantageously, when the piston 39 and the piston rod 41 are first mounted or before the press is used as an explosion press, the piston 34 of the pump 14 for supplying pressurized hydraulic fluid is mounted at its point. dead high to thus move the fluid contained above the pistons 12a to 12h of the hydraulic cylinders 11a to 11h in the reservoir 33 of the feed pump, by actuation of the lower and upper screw press during the admission of fresh air in the central cylinder 2. After that, the lower screw press, the oil distribution disc 15 are blocked to prevent the passage of the fluid from the reservoir 33 in the hydraulic cylinders 11a to 11h.

The hydraulic fluid remaining in the various variable volume chambers and the pistons of the hydraulic cylinders will move down or go up according to the movements of the central movable cylinder 2 and the central piston 39, without being subjected to the shock of the explosion.

Thus, the press of the invention which can be used as a hydraulic press when no fuel is injected into the combustion chamber 55 of the cylinders 44a and 44c and simply by switching on the lower screw press and the disc 15 of hydraulic fluid distribution, is transformed into an explosion press by their blocking and the injection of a fuel into the combustion chamber of the cylinders 44a to 44c causing the explosion of this fuel mixed with fresh air admitted in this room.

In conclusion, the press of the invention is of a reduced bulk and can by very simple and very rapid modifications be used according to an appropriate operating mode depending on the articles to be manufactured.

Claims (25)

1. A hydraulic, pneumatic, pneumatic-hydraulic or combined pneumatic-explosion press, particularly for the manufacture of products by compaction, sintering, pressing, forming, swaging or (illegible). The press comprises a piston tool (66) attached to a driving piston (64) supported by the splayed section (2b) of the lower section of a movable cylinder (2), the upper part of which slides inside a fixed guiding cylinder (4), coaxially suspended inside an intermediate cylinder (19) which, resting with its shoulder (27) and a contraction (28) on the broadened section (25) of a cylinder (5) forming the outer casing of the press, contains with this outer cylinder (5) an annular chamber (21) containing a coolant which is linked by a passage (32), formed in the widening of the outer cylinder (5) to a lower coolant tank (26). The same intermediate cylinder (19) contains within it the hydraulic mechanisms comprising several hydraulic cylinders (11a to 11 h), arranged in a crown around the movable cylinder (2). The movable cylinder is equipped with a contraction (7) on which rests a movable plate (8) sliding at the same time in a sealed state into the holes pierced in its base around the said hydraulic cylinders (11a to 11h) and through its cylindrical section (9) against the inner wall of the intermediate cylinder (19) defining with this and the guiding cylinder (4) a first variable volume chamber (10), permanently linked to a first lower variable volume chamber (13), situated in each hydraulic cylinder (11a to 11 h) and formed by the sliding action of the differential pistons (12a to 12h) in the upper section of each hydraulic cylinder between the lower surface of each free differential piston (12) and an opening (73) made in the side of each hydraulic cylinder, above the upper part of its extended section, ensuring a transfer of the pressure exerted by the hydraulic fluid from a hydraulic fluid feeding pump (14), successively filling the first upper variable volume chamber (13) which is situated in each hydraulic cylinder between its free differential piston (12) and the disc (15) acting as the base of the pump (14). The extended section of each hydraulic cylinder (11a a to 11 h) of a contracted inner section, into which the rod (16a to 16h) of each differential piston slides, is welded by its lower end to its respective hole, pierced in a fixed lower disc (18) welded to the lower end of a contracted section (22) of the intermediate cylinder (19) and situated in a driving piston (64) boring around the movable cylinder, to create a second variable volume' chamber (17a to 17h, 107) filled with hydraulic fluid between these and the underside of the rod (16a-to 16h) of each differential piston (12a to 12h). A third variable volume chamber comprising an upper chamber (23) situated above the movable partition (8) - between the central movable cylinder (2) and the intermediate cylinder (19) - and a lower chamber (24) positioned below the contraction (28) of the intermediate cylinder (19) and between its lower contracted section (22) and the lower wall (31) of the coolant tank (26). The two chambers are permanently connected via a hole (29) and, along with the other variable volume chambers (10, 13, 17a to 17h, 107), they form part of the hydraulic system of the press. This hydraulic system is characterised by the fact that the piston tool (66) and the movable cylinder (2), which are fixed to the driving piston (64), are subjected during their downward motion to a pressure coming from the hydraulic pressure mechanisms (11a to 11 h, 8,16a to 16h, 13, 17, 23, 24, 107) supported by the coordinated action of the pneumatic press system, especially its mechanical (41, 38, 2) and pneumatic pressure components (41, 39, 2). These also support the operation of the explosion system of the press so that a piston (39), sliding inside the movable cylinder (2) driven by an upper screw press (42, 43), compresses the fresh air drawn through a valve (59), and transports it along a pipe (63) and into a cylinder (44a to 44c) where it is mixed with the fuel so that the self-igniting mixture obtained creates a pressure independant from the hydraulic system, and exerted in the form of a controlled shock from the point of view of the strength and the depth which is determined by a stop element (57). The shock is successively repeated thanks to a piston (39) which is mounted so that it raises the movable cylinder (2) and the associated pistons (64, 66) to their starting position. The same components of the pneumatic system cause the return of the said pistons to their previous position in the event of the press being used as a hydraulic press.

2. A press as defined in claim 1, characterised by the fact that the fixed guiding cylinder (4), the intermediate cylinder (19) and the cylinder (5), acting as the casing of the press, are fixed by their respective upper splayed end (5a, 6, 20) to a supporting platform (1). The splaying of the fixed guiding cylinder (4) is achieved by means of a disc (6) containing grooved holes (71a a to 71h), each holding the upper end of a hydraulic cylinder (11a to 11 h) in a fixed position.

3. A press as defined in claim 1, characterised by the fact that the driving piston (64) is connected to the lower splayed end (2b) of the movable cylinder (2) by boring the centre of the driving piston.

4. A press as defined in claim 1, characterised by the fact that the movable partition (8) transfers the hydraulic pressure built up in the upper variable volume chambers (11 a to 11 h, 12a to 12h, 10, 13) on the driving piston (64) by means of the hydraulic fluid contained in the lower variable volume chambers (23, 24, 17, 107) as well as by direct mechanical action, given that the movable partition (8) rests on the flange (7) of the movable cylinder (2) firmly attached to the driving piston (64).

5. A press as defined in claim 4, characterised by the fact that the movable partition (8) slides into the openings made in its base the length of the movable cylinder (2) and the hydraulic cylinders (11a to 11h) in a semi-sealed manner, but without any sealed segments, thus enabling the pressure in the upper (11a to 11 h, 12a to 12h, 10, 13) and the lower variable volume chambers (23, 24, 17, 107) to be equal.

6. A press as defined in claim 5, characterised by the fact that the equalisation of hydraulic fluid pressure in the upper (11a to 11h, 12a to 12h, 10, 13) and the lower variable volume chambers (23, 24, 17, 107) is stimulated through small pressure equalisation holes pierced in the base of the movable partition (8).

7. A press as defined in claim 1, characterised by the fact that the hydraulic fluid feeding pump (14) comprises a fluid chamber (33) and a piston (34) fixed to-the upper end of the upper part (2a) of the contracted part of the central movable cylinder (2).

8. A press as defined in claim 7, characterised by the fact that the piston (34) in the pump (14) is driven by a screw press comprising a pinion (35), in contact with a driving wheel (36), and an upward-motion screw (37), in contact with a thread shaft which is connected to the piston (34) of the feeding pump (14).

9. A press as defined in claim 7, characterised by the fact that the base (15) of the feeding pump (14) rotates above the hydraulic cylinder (11a to 11h) ends, and comprises a single opening allowing the fluid to enter each hydraulic cylinder.

10. A press as defined in claim 1, characterised by the fact that the feeding pump (14) sends the hydraulic fluid successively to each hydraulic cylinder (11a to 11h).

11. A press as defined in claim 7, characterised by the fact that the volume of the feeder pump (14) fluid chamber (33) is equal to the sum of the volume of each hydraulic cylinder (11a to 11h) chamber when the free piston is bottom dead centre.

12. A press as defined in claim 1, characterised by the fact that the section of each hydraulic cylinder (11a to 11h) and the section of each variable volume cylinder (10, 17a to 17h, 23, 24, 107) are determined so that the pressure of the hydraulic fluid in each variable volume chamber is approximately the same as in each hydraulic cylinder.

13. A press as defined in claim 1, characterised by the fact that the broadened section (25) of the outer cylinder (5) also tends towards the inside of this cylinder in order to form the subsidiary tank (26) for a coolant such as water, the intermediate cylinder (19) presenting the shoulder (27) resting on this broadened section (25), (illegible) cylindrical section of the contracted part (22) in contact with the extended section of the hydraulic cylinders (11 a to 11 h).

14. A press as defined in claim 13, characterised by the fact that the subsidiary tank (26), which is in two-way connection with the annular chamber (21), is used to cool the combustion mechanisms (44a to 44c, 45a to 45c).

15. A press as defined in claim 1, characterised by the fact that the driving piston (64) comprises an upper cylindrical section (30) which slides into the space formed between the internal wall (31) of the broadened section (25) of the outer cylinder (5) and the section (22) of the contracted part of the intermediate cylinder (19).

16. A press as defined in claim 15, character- . ised by the fact that the pressure created in every system of the press, especially in its combined mechanical/pneumatic system, in the hydraulic system and the combined pneumatic/explosion system, is transferred to the piston tool (66) by the driving piston (64).

17. A press as defined in claim 1, characterised by the fact that the combined mechanical/pneumatic pressure comes from a mechanical device comprising an upper screw press (35 to 37) fitted on the driving lower screw press of the feeding pump (14) and comprising a pinion (42) in contact with a driving wheel (43) and an upward-motion screw (93) in contact with the threaded part of the rod (41). These are blocked in rotation together with the piston (39) which slides into the lower section of the movable cylinder (2), forming with the movable cylinder a container with variable volume linked on one side to the atmosphere via the automatic valve (59) and on the other side with the piston (62) chamber of the combustion cylinder (44) via the compressed air pipe (63) connected to the body of the driving piston (64). This causes therefore, during its upward motion towards the top dead centre, all the hydraulic pressure mechanisms to rise to their respective starting positions and fresh air to fill the lower section of the movable cylinder (2), and during its downward motion towards bottom dead centre, the .air in its container and in the chamber (62) of the cylinder (44) to be compressed simultaneously.

18. A press as defined in claim 17, character- . ised by the fact that the piston (39) rod (41 which slides into the movable cylinder (2) fixed to the driving piston (64) is disengaged during the explosion in order to avoid the shock being transmitted to the elements of the hydraulic system of the press.

19. A press as defined in claim 1, characterised by the fact that the disc (18) crossed by the movable cylinder (2) has openings provided and is fixed on to the lower end of the contracted section of the intermediate cylinder (19), housing the extended section of the hydraulic cylinders (11a to 11h) in the respective openings, to keep them welded in a vertical position.

20. A press as defined in claim 13, characterised by the fact that the broadened section (25) of the outer cylinder (5) comprises in its lower section at least one boring in order to receive the combustion mechanisms enabling a force to be applied to the piston tool (66).

21. A press as defined in claim 19, characterised by the fact that the combustion mechanisms comprise at least one cylinder (44), fitted with an outer casing (45), into which a piston (46) slides in a sealed state, projecting on the upper side of the annular section (47) of the driving piston (64), one inlet and outlet valve (48, 49), mechanisms for ignition and feeding fuel to the cylinder, a device for feeding compressed air to each cylinder (44), and an outlet pipe (50) fitted to the upper section of the cylinder (44) in the broadened section of the outer cylinder (5).

22. A press as defined in claim 20, characterised by the fact that the upper end of the piston (46) forms a valve face (51) for the block (52) of the inlet valve, and the upper section of the cylinder (44) forms another valve face (53) for the block (54) of the outlet valve (49). A combustion chamber (55) is defined between the upper section of the cylinder (44) and the upper end of the piston (46).

23. A press as defined in claim 21, characterised by the fact that the rod (56) of the outlet valve (49) of the cylinder (44) crosses the annular section (47) of the driving piston (64) and comprises the element acting as a stop (57) on its projecting section in order to cause the outlet valve (49) to open after travelling in the direction determined by the driving piston (64).

24. A press as defined in claim 21, characterised by the fact that the cylinder (44) inlet valve (48) comprises a longitudinal boring into which the body (58) of the cylinder (44) outlet valve (49) is slid coaxially.

25. A press as defined in any one of the previous claims, characterised by the fact that the press tools (3, 65, 66) are fixed to the driving piston in such way that they may be removed, the elements (65, 66) of the press tool conforming to the form of the product to be manufactured.

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