APPARATUS AND PROCESS FOR THE PRODUCTION OF MECHANICAL PIECES WITH SMALL SIZE

Field of the Invention

In its most general aspect the present invention relates to the technical field of small parts and, in particular, the so-called workshop small parts.

More particularly, the invention relates to an apparatus for the production of mechanical pieces with small size such as, for example but not only, bolts, small bolts, nuts, washers, rings, plugs, studs, tangs and balls for valves, joints, reduction units, hose connecting elements, ring nuts, swivel nuts and similar small mechanical pieces made of metal or plastic material.

The invention also relates to a process for manufacturing mechanical pieces of the aforementioned type.

State of the art

As known, in the field of small parts and particularly the so-called workshop small metal parts, small mechanical parts such as bolts, small bolts, nuts, washers, rings, plugs, studs, tangs and balls for valves, joints, reduction units, hose connecting elements, ring nuts, swivel nuts and the like, are generally produced through a closed-mold process.

Although a method of the aforesaid type meets the purpose, it is not free from drawbacks including high cost of molds, which in practice are made by two half-shells containing the impression of the mechanical piece to be made.

Moreover, by closing the mold containing the molten metal to be formed and subsequently opening the mold with the shaped metal, unwanted imperfections are caused on the obtained mechanical pieces, the so-called flow marks.

Again, closed-mold processes require a step of ejecting the mechanical pieces from the mold, which is mechanically actuated by a special ejector, that is to say a pin arranged in the mold and acting on the formed mechanical piece, during or after the step of opening of the mold.

The use of ejectors causes other drawbacks including the risk of developing further irregularities or imperfections on formed mechanical pieces, long residence time in the molds and, as a result, undesired overheating of formed pieces, as well as general slowdown of the molding process, and finally the structural complexity of the molds and thus of the entire equipment used in processes of the type considered herein is increased.

Structure and operation of known apparatuses used in processes of the type considered herein are further complicated by the so-called part pickers, namely those mechanical members also known as spoons or collectors, which move between one mold and the other, or between two half-shells of a mold, to pick up the shaped pieces ejected from the molds.

Summary of the invention

The technical problem underlying the present invention is to provide an apparatus for making small mechanical parts, i.e. mechanical pieces with small sizes, for example made of metal or plastic material such as, for example but not only, bolts, small bolts, nuts, washers, rings, plugs, studs, tangs and balls for valves, joints, reduction units, hose connecting elements, ring nuts, swivel nuts and the like, having structural and functional characteristics such as to overcome one or more of the drawbacks mentioned above with reference to the known art.

According to the invention, the aforesaid problem is solved by an apparatus for making mechanical pieces, particularly but not exclusively, of the aforesaid type, comprising at least one first plunger and one second plunger both movable and opposed one to another; at least one die interposed between the aforesaid first plunger and the aforesaid second plunger and intended to receive at least one semifinished product to be formed, for example a heated billet made of metal or plastic material; at least one guide extended between the aforesaid die towards the aforesaid first plunger to feed the aforesaid semifinished product into the aforesaid die by the aforesaid first plunger; at least one discharge channel extended at the side of the aforesaid die that is opposite to the aforesaid guide in order to pick up at least one formed mechanical piece obtained from the aforesaid semifinished product; and movement means to move the aforesaid first plunger and the aforesaid second plunger, wherein the aforesaid first plunger and second plunger are movable between at least one first position, in which they are distal from the aforesaid die, and a second position in which they are proximal to the aforesaid die, in the aforesaid second position at least the aforesaid second plunger having a head portion inside the aforesaid die.

According to the invention, the aforesaid apparatus can be substantially considered a sort of horizontal hot extrusion apparatus, since the material to be formed, i.e. the aforesaid semifinished product, heated, enters the aforesaid die from one side and comes out formed, i.e. as a finished mechanical piece, from an opposed side of the aforesaid die, and passes through the latter, as better understood hereinafter.

According to the invention, the afore said apparatus can also be considered a sort of horizontal open-die forging machine without a classic dedicated ejector and a classic dedicated part picker, since the aforesaid mechanical piece is extracted from the aforesaid die, which precisely constitutes a basically open die, and retained directly by the afore said second plunger which cooperates in shaping the desired mechanical piece, as will become apparent hereinafter.

Preferably, the aforesaid apparatus comprises countering means and, in particular, at least one countering member outside of the aforesaid die and arranged, with respect to the latter, at the same side of the aforesaid discharge channel and which is crossed by the aforesaid second plunger while the latter is moving from the aforesaid first position to the aforesaid second position and vice versa, and which is adapted to counter the aforesaid mechanical piece thus removing the latter from the aforesaid head portion of the aforesaid second plunger in particular during the movement of the aforesaid second plunger from the aforesaid second position to the aforesaid first position.

Preferably, the aforesaid at least one countering member is a hollow body, for example a hollow cylinder, in which the aforesaid second plunger slides, and more preferably is a movable hollow body or cylinder, the aforesaid second plunger and the aforesaid movable hollow body or cylinder constituting a so-called double-stroke cylinder or telescopic cylinder on which the aforesaid movement means operate.

Preferably, the aforesaid movement means, for example of oleodynamic, pneumatic, electric type, comprise first movement means and second movement means independent from one another and operating on the aforesaid first plunger and, respectively, on the aforesaid second plunger or the aforesaid double-stroke cylinder.

Preferably, the aforesaid apparatus comprises a plurality of first plungers and second plungers of the aforesaid type, on which the aforesaid first movement means and, respectively, the aforesaid second movement means operate, and a plurality of dies of the aforesaid type, each interposed between a first plunger and a second plunger, then a plurality of guides of the aforesaid type, one guide per each die.

Preferably, the dies of the aforesaid plurality of dies are housed or obtained in a die-holder member, more preferably a die-holder member spanning between the aforesaid guides, and even more preferably removably combined with a loadbearing body of the aforesaid apparatus.

Preferably, the aforesaid apparatus comprises at least one first motorized loader, to feed a plurality of semifinished products of the aforesaid type to the aforesaid at least one guide, thus one semifinished product at a time, or to feed, at the same time, a plurality of semifinished products to the aforesaid plurality of guides, therefore a semifinished product per each aforesaid guide.

Preferably, the aforesaid first loader comprises at least one first movable ramp, wherein the aforesaid first ramp can be displaced between one or more first load positions of semifinished products and a second unload position of semifinished products, wherein in the aforesaid second unload position the aforesaid first ramp spans on the aforesaid guides.

Preferably, the aforesaid first ramp comprises two essentially flat members coupled to one another, essentially overlapped and at least in part sliding with respect one another, wherein the aforesaid two essentially flat members are provided with respective openings, wherein in the aforesaid one or more load positions the aforesaid respective openings are staggered, and wherein in the aforesaid second unload position the aforesaid respective openings are aligned one to another and are aligned with the aforesaid guides.

Preferably, the aforesaid apparatus comprises a second motorized loader opposed and substantially equal to the aforesaid first loader, wherein the aforesaid second loader comprises at least one second movable ramp opposed and substantially equal to the aforesaid first ramp, wherein the aforesaid first ramp and the aforesaid second ramp reciprocate in the respective second unload positions of the aforesaid semifinished products.

Preferably, the aforesaid apparatus comprises at least one first limit member selectively operating on one or the other of the aforesaid two essentially flat members of the first ramp, and possibly comprises a second limit member selectively operating on one or the other of the two essentially flat members of the aforesaid second ramp.

Preferably, the aforesaid apparatus comprises at least one first cutting station to obtain the aforesaid at least one semi-finished product with predetermined desired size, for example from a bar, a block, an ingot and similar pieces of large sizes at a predetermined temperature, wherein the aforesaid first cutting station is arranged upstream of the aforesaid at least one first loader.

Preferably, the aforesaid apparatus comprises a second cutting station opposed and substantially equal to the aforesaid first cutting station, wherein the aforesaid second cutting station is arranged upstream of the aforesaid second loader.

Preferably, the aforesaid apparatus comprises at least one first heating station, for example a furnace, for heating bars, blocks, ingots and similar pieces of metal or plastic material, which is arranged upstream of the aforesaid first cutting station and more preferably comprises a second heating station opposed and substantially equal to the aforesaid first heating station and arranged upstream of the aforesaid second cutting station.

According to the invention, the aforesaid problem is also solved by a process for making mechanical pieces of the aforementioned type, comprising the steps of:

• providing, at a preset temperature, one or more semifinished products to be formed, for example one or more heated billets of plastic or metal material such as for example brass, aluminum, copper and similar metals or metal alloys used in producing small parts;
• feeding the aforesaid one or more semifinished products to respective one or more guides;
• transferring the aforesaid one or more semifinished products from the aforesaid one or more guides to one or more dies by respective one or more first plungers, wherein the aforesaid one or more first plungers are movable, sliding in the aforesaid one or more guides and operate on the aforesaid one or more semifinished products;
• moving one or more second plungers closer to the aforesaid one or more dies, wherein the aforesaid one or more second plungers are movable and opposed to the aforesaid one or more first plungers;
• forming, in the aforesaid one or more dies, one or more respective mechanical pieces of preset shape by plastically deforming the aforesaid one or more semifinished products by operating thereon through the action of the aforesaid one or more first plungers and the aforesaid one or more second plungers;
• moving the aforesaid one or more second plungers away from the one or more dies with consequent and concurrent extraction therefrom of the aforesaid one or more mechanical pieces.

Preferably, the aforesaid process further comprises a step of:

• further moving the aforesaid one or more second plungers away from the aforesaid one or more dies, while removing from the former the aforesaid one or more mechanical pieces by the action of one or more countering members, the aforesaid one or more countering members respectively operating on the aforesaid one or more mechanical pieces as the aforesaid one or more second plungers are further moving away from the aforesaid one or more dies;
• and preferably comprises a picking-up step wherein the aforesaid one or more mechanical pieces are conveyed in at least one discharge channel.

Preferably, in case of a number of semifinished products, the aforesaid semifinished products are fed at the same time to the respective guides, and more preferably the movements of the respective first plungers are synchronized one to another.

Preferably, in case of a number of semifinished products, the movements of the respective second plungers are synchronized one to another.

Preferably, the movements of the aforesaid one or more first plungers and the movements of the aforesaid one or more second plungers are synchronized, or substantially synchronized, one to another.

Preferably, the aforesaid process comprises at least one cutting step, wherein the aforesaid semifinished products are obtained by cutting one or more pieces such as, for example, bars, blocks or ingots of metal material or plastic material.

Preferably, the aforesaid at least one cutting step is carried out under heat, the aforesaid process comprising, before the cutting step, at least one step of heating the aforesaid one or more pieces.

BRIEF DESCRIPTION OF THE FIGURES

Further characteristics and advantages of the invention will be more evident by the review of the following description of a preferred, but not exclusive, embodiment depicted for illustration purposes only and without limitation, with the aid of the attached drawings, in which:

• figure 1 schematically shows a partially phantom side view of an apparatus for producing mechanical pieces according to a first embodiment of the present invention;
• figure 2 schematically shows a partially phantom plan view of the apparatus of figure 1;
• figure 3 schematically shows a front view of the apparatus of figure 1,
• figures 4-7 schematically show side views of an enlarged detail of the apparatus of figure 1, during four different operating steps of making a mechanical piece according to the present invention;
• figure 8 schematically shows a partially phantom plan view of the apparatus of figure 1 according to a variation of the embodiment of the invention;
• figure 9 schematically shows an enlarged detail of the apparatus of figure 8;
• figure 10 schematically shows a plan view of a further enlarged detail of the apparatus of figure 8.

Detailed description of the invention

Referring to figures 1-7, an apparatus for making mechanical pieces according to a first embodiment of the present invention is denoted as a whole by the reference number 1.

In particular, but not exclusively, the apparatus 1 is adapted to the make mechanical pieces with small size of metal or plastic material, namely mechanical pieces with small size such as, for example but not only, bolts, small bolts, nuts, washers, rings, plugs, studs, tangs and balls for valves, joints, reduction units, hose connecting elements, ring nuts, swivel nuts and the like.

The apparatus 1 basically comprises a first movable plunger 2, a second plunger 3 also movable and opposed to the first plunger 2, and a die 4 interposed between the first plunger 2 and the second plunger 3.

In particular, the first plunger 2 and the second plunger 3 are movable between a first position, in which they are distal from the die 4, and a second position in which they are proximal to the die 4.

In detail, the die 4 is adapted, and thus intended, to receive a respective semifinished product to be formed, for example a heated billet of metal material or plastic material, in the examples of the figures denoted by A, and therefore is shaped, in particular inside, according to the outer shape of the desired mechanical piece.

The apparatus 1 further comprises a guide 5 extended between the die 4, and precisely therefrom, towards the first plunger 2 to feed the semifinished product A into the die 4 by means of the first plunger 2.

Additionally, the apparatus 1 comprises a discharge channel 6 extended at the side of the die 4 that is opposite to the guide 5 in order to pick up the mechanical piece, in figures denoted by B, formed and obtained from said semifinished product A.

The apparatus 1 further comprises movement means for moving the first plunger 2 and the second plunger 3, in particular according to the examples in figures, respectively first movement means 7 and second movement means 8 independent from one another.

It should be said in addition that, as regard in detail the movement of the first plunger 2 and the second plunger 3, according to the invention the first plunger 2 essentially pushes the semifinished product A into the die 4, i.e. substantially loads in the die 4 the semifinished product A to be formed by feeding it along the guide 5, while the second plunger 3, by a respective head portion 9, pushes into the die 4 to form the desired mechanical piece B by plastically deforming the semifinished product A.

To that purpose, the head portion 9 of the second plunger 3, and possibly also a respective head portion of the first plunger 2, has predetermined shape according to the desired shape of the mechanical piece to be obtained.

In fact, since the mechanical piece B remains substantially fitted on the head portion 9 of the second plunger 3, the second plunger 3, while moving back to the first position, that is to say while moving away from the die 4, also extracts the mechanical piece B from the die 4.

Therefore, the mechanical piece B is extracted from the die 4 without the aid of a specific ejector inside the die 4, an ejector being, de facto, completely absent in the present apparatus.

In detail, the apparatus 1 comprises countering means to remove the mechanical piece B from the second plunger 3 and precisely, according to the examples of the aforesaid figures, comprises a countering member denoted by the reference number 10, outside of the die 4 and arranged, with respect to the latter, at the same side of the discharge channel 6.

The countering member 10, or anyway a portion thereof operating on the mechanical piece B, is virtually crossed or overtaken by the second plunger 3, while the latter is moving from the first position to the second position and vice versa.

In particular, while the second plunger 3 is moving from the second position to the first position, the countering member 10 is adapted to counter the mechanical piece B fitted on the head portion 9 of the second plunger 3, thereby removing the mechanical piece therefrom and basically pulling it out of the second plunger 3 and dropping it into the discharge channel 6.

According to the examples in figures, the countering member 10 takes shape as a hollow cylinder in which the second plunger 3 slides, in particular takes shape as a movable hollow cylinder constituting, together with the second plunger 3, a so-called double-stroke cylinder or telescopic cylinder denoted as a whole by the reference number 11.

The second movement means 8 which, as well as the first movement means 7, may include hydraulic, pneumatic, electric pistons and similar movement means, operate on the double-stroke cylinder 11, with a double effect.

According to the examples of the figures, the apparatus 1 also comprises a die-holder member 12 in which the die 4 is housed or obtained in one piece.

Therefore, advantageously the die-holder member 12 spans on the guide 5, and advantageously is removably combined with a loadbearing body of the apparatus 1, denoted as a whole by the reference number 13.

Furthermore, the apparatus of the present invention may comprise a loader, not shown in the aforesaid figures, advantageously a motorized loader to feed or load a sequence of semifinished products A to the guide 5, one semifinished product at a time.

Referring to figures 8-10 an apparatus 101 for making mechanical pieces according to a second embodiment of the present invention is now described, in which parts operationally corresponding to those of the above described apparatus 1 have the same reference numbers.

Reference should be made to the description of apparatus 1, which is substantially fully similar to the apparatus 101, although the latter is able to make a plurality of mechanical pieces B at the same time and therefore includes a plurality of first plungers 2, a plurality of second plungers 3 each having a respective head portion 9, a plurality of dies 4 and a plurality of guides 5, whereas for picking up mechanical pieces B a single common discharge channel 6 is provided.

Still similarly to the apparatus previously described with reference to figures 1-7, the description of which should be used as reference, the apparatus 101 also comprises a countering member common to the second plungers 3, or a countering member per each of the second plungers 3, denoted by the reference number 10.

The countering member can be movable, for example a hollow cylinder, and together with the second plungers 3 may form a single double-stroke cylinder or several double-stroke cylinders, or it can be fixed, for example a perforated wall, and in any case it is crossed by the second plungers 3.

Still similarly to the apparatus 1 the description of which should be used as reference, the apparatus 101 comprises first movement means 7 and second movement means 8 independent from each other and respectively operating on the first plungers 2 and on the second plungers 3.

Still similarly to what stated above, the apparatus 101 includes a die-holder member 12 in which the dies 4 are housed or obtained in one piece and which advantageously spans on the guides 5 and which is advantageously removably combined with a loadbearing body 13 of the apparatus 101.

In detail, to simultaneously make a plurality of mechanical pieces B, the apparatus according to the present invention comprises at least one loader to feed simultaneously a plurality of semifinished products A to the plurality of guides 5 and preferably, according to the examples of figures 8-10, it comprises a pair of loaders 114, in particular a first and a second loaders both motorized and arranged opposed to each other.

Each loader 114 includes a respective movable ramp 115, thus respectively a first ramp and a second ramp which can be both displaced, alternately to one another, between one or more first load positions of the semifinished products A and a second unload position of the semifinished products A, wherein in the second unload position the first ramp, and alternately the second ramp, essentially span on the plurality of guides 5.

The first ramp and the second ramp 115 each comprise two essentially flat members, not shown in the examples of figures, coupled to one another, essentially overlapped and sliding with respect to one another, in particular near the second position of the ramps.

Each of the two essentially flat members is provided with respective openings so that, in the load position or positions, the respective openings of the two essentially flat members are staggered with respect to one another thus allowing the semifinished products A to be transported, while in the second unload position the respective openings are aligned one to another and are aligned with the guides 5 to allow the semifinished products A to be unloaded on the same guides 5.

Substantially the first ramp, after being loaded, feeds at the same time a plurality of semifinished products A to the guides 5 while the second ramp is being loaded, subsequently the second ramp feeds at the same time a plurality of semifinished products A to the guides 5 while the first ramp goes back to the first position or positions, to be loaded again.

For the reciprocal sliding of the two essentially flat members of the first guide and of those of the second guide, the apparatus 101 comprises a first limit member and respectively a second limit member, not shown in the examples in figures, which selectively operate on one or the other of the two essentially flat members of the first ramp and respectively of the second ramp.

Still, the apparatus 101 comprises at least one cutting station to obtain, from a heated piece such as a bar, a block or an ingot of metal material or plastic material, the semifinished products A with predetermined desired sizes, and according to the examples of the figures, comprises two cutting stations 116, a first cutting station arranged upstream of the first loader, and a second cutting station arranged upstream of the second loader.

The apparatus 101 also comprises at least one heating station, for example a furnace, for heating the aforesaid pieces to be cut and denoted by C and, according to the examples of the figures, comprises two heating stations 116, a first heating station arranged upstream of the first cutting station and a second heating station arranged upstream of the second cutting station.

According to a further aspect of the invention and according to what above described, a process for making mechanical pieces B of the above considered type and carried out with the apparatus described above in its various embodiments, comprises the steps of:

• providing, at a preset temperature, one or more semifinished products A to be formed, for example one or more heated billets of plastic material or brass, aluminum, copper and similar metals or metal alloys used in producing small parts;
• feeding the one or more semifinished products A to respective one or more guides 5;
• transferring the one or more semifinished products A from the one or more guides 5 to one or more dies 4 by respective one or more first plungers 2, wherein the one or more first plungers 2 are movable, sliding in the one or more guides 5 and operating on the one or more semifinished products A;
• moving one or more second plungers 3 closer to the one or more dies 4, wherein the one or more second plungers 3 are movable and opposed to the one or more first plungers 2;
• forming, in the one or more dies 4, one or more respective mechanical pieces B of preset shape by plastically deforming the one or more semifinished products A by operating thereon through the action of the one or more first plungers 2 and the one or more second plungers 3;
• moving the one or more second plungers 3 away from the one or more dies 4 with consequent and concurrent extraction of the one or more mechanical pieces B from the one or more dies 4.

The present process advantageously comprises also a step of automatically recovering the mechanical pieces B, and precisely a step of further moving the one or more second plungers 3 away from the one or more dies 4, while removing the one or more mechanical pieces B from the one or more second plungers 3 by the action of one or more countering members 10, wherein the one or more countering members 10 are respectively operating on the one or more mechanical pieces B as the one or more second plungers 3 are further moving away from the one or more dies 4.

Moreover, advantageously, the mechanical pieces B pulled out of the one or more seconds plungers 3 are picked up, that is to say dropped into a discharge channel 6, while the return movement of the one or more first plungers 2 to the respective first positions allows the one or more guides 5 to become free for a further cycle of this process.

Additionally, according to the invention, it should be said that if several semifinished products A, thus a plurality of semifinished products, are fed, they are simultaneously fed to the respective guides 5 and, advantageously, the movements of the respective first plungers are synchronized one to another.

Furthermore, in the case of several semifinished products A, also the movements of the respective second plungers 3 are synchronized one to another.

Moreover, according to the invention, the movements of the one or more first plungers 2 and of the one or more second plungers 3 are synchronized or substantially synchronized one to another.

According to the invention, the present process further comprises a cutting step in which the one or more semi-finished products A are obtained by cutting one or more pieces of plastic material or metal material, such as bars, blocks or ingots denoted by C.

Advantageously, the cutting step is carried out under heat, the present process comprising, before the cutting step, at least one step of heating the one or more pieces C.

Advantageously, the heating step can continue even after the cutting step of one or more pieces C, thus heating the one or more semifinished products A, for example by heating the one or more dies 4 and/or the one or more guides 5 and/or the one or more first plungers 2 and/or the one or more second plungers 3, by specific heating means, for example electrical resistances and/or circulation of a diathermal fluid in suitable circuits, in the examples of the figures the heating means not being shown.

The advantages of the present invention, already highlighted in the above stated description, can be summarized noticing that an apparatus for making mechanical pieces particularly, but not exclusively, with small sizes is provided, the apparatus having increased structural and functional simplicity and allowing to remarkable increase the mechanical pieces produced per time unit with respect to known apparatuses.

In addition, mechanical pieces essentially without defects, such as flow marks, are obtained thanks to an apparatus without ejectors, without part pickers and without closed dies.

In order to meet incidental and specific requirements, several variations and modifications could be made by a field technician to the illustrated and described embodiments of present invention, provided that all are included in the scope of protection of the invention as defined by the following claims.