WO2014177998A1

WO2014177998A1 - Machining center

Info

Publication number: WO2014177998A1
Application number: PCT/IB2014/061074
Authority: WO
Inventors: Alberto Ruggieri
Original assignee: Paolino Bacci S.R.L.
Priority date: 2013-05-03
Filing date: 2014-04-29
Publication date: 2014-11-06
Also published as: ITFI20130098A1

Abstract

The machining center comprises at least one operating head (5) movable according to a plurality of numerically controlled axes (A, C, X, Z) and at least one workpiece-holding slide (17) movable between a working area and an area where the workpieces to be machined are loaded on the workpiece-holding slide and machined workpieces are unloaded from the workpiece-holding slide, and vice versa. The machining center furthermore comprises at least one blocking member (19) carried by the workpiece-holding slide (21), to block at least one workpiece (P1, P2) on the same workpiece-holding slide. The blocking member comprises at least one lower clamping element (33) and at least one upper clamping element (31), both movable with respect to the workpiece-holding slide (21). An insertion system (39) for inserting the workpieces to be machined onto the blocking member (19) and a removal system (45) for removing the machined workpieces from the blocking member are also provided. The insertion system of the workpieces to be machined and the removal system of the machined workpieces are arranged at two different distinct heights and overlap each other, at least partially.

Description

MACHINING CENTER

Description

Technical Field

The present invention relates to machine tools or machining centers for machining workpieces, especially, although without limitation, workpieces made of wood, aluminum, plastic, or the like. More in particular, the invention relates to improvements to systems for loading workpieces to be machined on the workpiece- holding slide and removing machined workpieces from the workpiece-holding slide. State of the Art

Currently, machining centers or machine tools are known, with systems for manually loading the workpieces to be machined, wherein the operator shall move a workpiece to be machined towards a workpiece-holding slide having a series of clamping jaws, each of which is provided with an upper element and with a lower element. The upper element is fixed and acts as reference stop. The operator rests the workpiece on the upper clamping elements and holds it until the lower clamping elements have been raised and support the workpiece to be machined by holding it against the upper clamping elements. These systems have some disadvantages due to the difficult load of the workpieces. Moreover, unloading of the machined workpieces and loading of the new workpieces to be machined occur in sequence and require relatively long times.

There is therefore the need for providing machine tools or machining centers with more efficient systems for loading and unloading the workpieces.

Summary of the Invention

Essentially, to solve completely or partially the problems of the prior art machining centers, a machining center or machine tool is provided for machining pieces made of wood or the like, especially elongated pieces, comprising at least one operating head movable according to a plurality of numerically controlled axes and at least one workpiece-holding slide movable between a working area and an area where workpieces to be machined are loaded on the workpiece-holding slide and machined workpieces are unloaded from the workpiece-holding slide, and vice versa. The machining center may also comprise at least one blocking member carried by the workpiece-holding slide to block at least one workpiece on the workpiece-holding slide, wherein the blocking member comprises at least one lower clamping element and at least one upper clamping element that are both movable with respect to the workpiece-holding slide to block a workpiece to be machined there between. Moreover, the machining center may advantageously comprise an insertion system for inserting the workpieces to be machined onto the blocking member and a removal system for removing the machined workpieces from the blocking member. The insertion system of the workpieces to be machined and the removal system of the machined workpieces are advantageously arranged at two different and distinct heights and overlap each other, at least partially. Moreover, the lower clamping element advantageously defines a positioning and reference stop for the workpieces to be machined and is movable so as alternatively to move to the height of the insertion system of the workpieces to be machined and to the height of the removal system of the machined workpieces. In this way, an operator can transfer manually a workpiece to be machined from the insertion system towards and between the upper clamping element and the lower clamping element, this latter defining the position of the workpiece to which the machining coordinates refer. The workpiece may stay in this position, whilst the upper clamping element moves downwards until it blocks the workpiece between the two clamping elements.

As the machining coordinates refer to the position defined by the lower clamping element, no significant effort is necessary for the operator to position the workpiece and hold it in position until it is clamped by means of the upper clamping element. It is sufficient that the operator makes the workpiece slide, for instance by translating it along a rest surface until the workpiece rests on the lower clamping element. At this point, the workpiece cannot move and is therefore fixed in the position to which all the machining coordinates refer. The subsequent clamping by means of the downwards movement of the upper clamping element does not cause any displacement of the workpiece. In this way, it is not necessary for the operator to hold the workpiece suspended abutting against the upper clamping element, as it would be instead necessary in the case the machining coordinates were referred to the upper clamping element and the blocking would occur by lifting the lower clamping element.

In advantageous embodiments, the lower clamping element may have an actuation system defining only two positions or stroke end positions of the lower clamping element. The first position corresponds to the reference position, and is advantageously approximately at the height of the insertion system for inserting the workpiece to be machined, for instance approximately at the height of a rest surface for the workpiece to be machined, or at a slightly lower height. In this way, the operator can easily transfer the workpiece into the blocking member simply by making it slide on the rest surface. The second position is at the same height as the removal system for removing the machined workpieces. For the sake of ergonomics and to have less interferences, the insertion system for inserting the workpieces to be machined is preferably at a greater height than the removal system for removing the machined workpieces, and overlaps it at least partially

In some preferred embodiments, the insertion system for inserting the workpieces to be machined has advantageously a rest surface for the workpieces, which can be also formed by two or more rest shelves and can be accessed by the operator. During the loading step, the blocking member is on the opposite side of the rest surface with respect to the operator's position. In this way between the operator and the lower clamping element there are no obstacles, and the operator can easily rest a workpiece to be machined on the rest surface and make it slide towards and above the lower clamping element, with a minimum effort.

As the lower clamping element forms the reference stop for the workpiece and is in a fixed position, whilst, vice versa, the clamping force is generated by the upper clamping element, it is possible to block workpieces to be machined whose weight is not limited by the standards limiting the clamping efforts that can be applied by means of the workpiece clamping elements. Indeed, according to current standards, a clamping element cannot apply a force greater than 5 kg onto the workpiece to be blocked. Supposing to have a system with double clamping members, in case the blocking would occur from the bottom against upper clamping elements which are fixed or anyway defining the reference position of the workpiece, on this latter a force greater than 5x2=10 kg should not be applied. Vice versa, by using the lower clamping elements as elements defining the stop and reference position of the workpiece and using, vice versa, the upper clamping elements as pressing and blocking members, the workpiece to be machined can have any weight, supported by the lower clamping elements. It will be always clamped with a force Nx5kg, where N is the number of upper clamping elements, each of which applies a force no greater than 5 kg.

Further advantageous characteristics and embodiments of the machining center according to the invention will be defined in the attached claims, which form an integral part of the present description.

Brief description of the drawings

The invention shall be better understood by following the description and accompanying drawing, which shows non-limiting practical embodiments of the invention. More in particular in the drawing, wherein equal or equivalent parts are indicated with the same reference numbers:

figure 1 is a side view of a machining center in a first embodiment and in a position of the workpiece-holding slide;

figure 2 shows a view analogous to that of figure 1 with a different position of the workpiece-holding slide; and

figure 3 is a plan view according to III-III of figure 2.

Detailed description of embodiments of the invention

The detailed description below of example embodiments is made with reference to the attached drawings. The same reference numbers in different drawings identify the equal or similar elements. Furthermore, the drawings are not necessarily to scale. The detailed description below does not limit the invention. The protective scope of the present invention is defined by the attached claims.

In the description, the reference to "an embodiment" or "the embodiment" or "some embodiments" means that a particular feature, structure or element described with reference to an embodiment is comprised in at least one embodiment of the described object. The sentences "in an embodiment" or "in the embodiment" or "in some embodiments" in the description do not therefore necessarily refer to the same embodiment or embodiments. The particular features, structures or elements can be furthermore combined in any adequate way in one or more embodiments.

In some embodiments, the machining center, indicated as a whole with number 1, comprises a support structure 3 bearing an operating head 5. The exemplary embodiment illustrated in figures 1 to 3 comprises a structure 3 with a movable column. The configuration of the support structure 3 bearing the head 5 may be clearly different from that represented. A fixed column or a gantry structure may be for instance provided.

Just by way of example, the support structure 3 comprises a column 7, carried by a base 9. The column 7 is movable according to a numerically controlled axis of translation X (see figure 3). In some embodiments, the base 9 comprises guides 1 1 onto which shoes of the movable column 7 engage.

In some embodiments, the column 7 comprises guides 13 ' to allow the movement of the operating head 5 according to a numerically controlled vertical axis of translation Z. A slide 15 supporting the operating head 5 may for instance engage on the guides 13. The operating head may be provided with a rotary movement according to a first numerically controlled rotary axis A, for instance horizontal. According to some particularly advantageous embodiments, the operating head 5 is movable according to a further numerically controlled rotary axis C, for instance vertical.

The operating head 5 may comprise a plurality of electro-spindles 17. In the illustrated example, the operating head 5 has a crosswise head with four electro- spindles, each of which provided with a tool U. It should be understood that this is only an exemplary embodiment. In other embodiments, the operating head 5 may comprise a different, greater or lower, number of electro-spindles with respect to the represented number.

A further base 20, onto which a workpiece-holding slide or table 21 is mounted, may be associated with the base 9 and the column 7 forming the support structure 3 bearing the operating head 5. As shown in the drawing, the bases 9 and 20 may be fixed to a floor independently of each other. In other embodiments, the two bases may be directly connected to each other to form a monolithic structure.

The workpiece-holding slide 21 is movable along the base 20 in a direction of translation Y according to a numerically controlled axis. In some embodiments the workpiece-holding slide 21 is guided on guides 23 carried by the base 20.

As shown in particular in figure 1, the workpiece-holding slide 21 may move according to the numerically controlled axis of translation Y between a working area, in correspondence of the operating head 5, and an area, indicated as a whole with number 29 and spaced from the operating head 5, for loading the workpieces to be machined and unloading the machined workpieces. A broken line in figure 1 indicates the position of the workpiece-holding slide 21 in the working position, whilst a solid line indicates a position of the workpiece-holding slide 21 in the area 29 of loading the workpieces to be machined and unloading the machined workpieces.

The workpiece-holding slide 21 may carry one or more pairs 19A of clamping elements for clamping workpieces to be machined. The pairs 19A of clamping elements form a blocking system, indicated as a whole as blocking member 19 of the workpiece-holding slide 21.

In some embodiments, each pair of clamping elements comprises an upper clamping element 31 and a lower clamping element 33. The clamping elements 31, 33 form clamping jaws 19 A. Each clamping jaw 19A may be advantageously carried by a support 35. The supports 35 may be two or more, as schematically shown in figure 3. Each pair 19A of clamping elements may be advantageously adjustable according to the double arrow fl9 (figure 3) along a direction parallel to the axis of translation X and therefore orthogonally to the axis of translation Y of the workpiece- holding slide 21. To this end, guides 36 may be advantageously provided, carried by the workpiece-holding slide or table 21.

In some embodiments, both the upper clamping element 31 and the lower clamping element 33 of each pair 19A are vertically movable according to the double arrows f31 and f33 respectively.

In advantageous embodiments, the lower clamping element 33 is movable between two end positions shown in figures 1 and 2. The highest position of the lower clamping element 33 is shown in figure 2, while the lowest position of the lower clamping element 33 is shown in figure 1.

The upwards and downwards movement of the lower clamping element 33 according to the double arrow f33 may be imparted by means of a cylinder-piston actuator, whose piston rods connecting the cylinder-piston actuator to the lower clamping element 33 are indicated with 37. Also other actuators may be used, for instance mechanical jacks.

Also the upper clamping element 31 is advantageously movable according to the double arrow f31 , and this movement may be controlled by means of a cylinder- piston actuator, not shown, or by means of any other suitable actuator.

While the lower clamping element 33 has preferably only two positions respectively of maximum rise and maximum fall, as described above, the upper clamping element 31 can take, in vertical direction, a variable position according to the vertical dimension, i.e. to the thickness, of the workpiece to be machined, so that this latter can always be correctly blocked and clamped between the lower clamping element 33 and the upper clamping element 31 of each pair 19 A.

An insertion system, for inserting the workpieces to be machined onto the blocking member 19 carried by the workpiece-holding slide 21, and a removal system, for removing the machined workpieces from the blocking member 19 carried by the workpiece-holding slide 21, may be provided in the area 29 of loading the workpieces to be machined and unloading the machined workpieces.

In some embodiments, the insertion system for inserting the workpieces to be machined simply comprised rest shelves 39 arranged at a first height HI with respect to a floor Pv (figures 1 and 2).

The shelves 39 may be carried by a support structure 40 (figure 3) and may have a variable and adjustable reciprocal distance. In some embodiments the shelves 39 may be joined together to form a single rest surface that, if necessary, can be telescopically elongated in a direction parallel to the axis X. The dimension of the rest surface, i.e. the reciprocal distance between the two shelves 39, can be adjusted to adapt to workpieces to be machined of various sizes.

Vertical stop surfaces 41 can be associated with the shelves 39 or the rest surface.

The removal system for removing the machined workpieces is at a height H2, lower than the height HI of the insertion system for inserting the workpieces to be machined, for the purposes explained below.

In some embodiments, the removal system for removing the machined workpieces may comprise extractors 45 provided with a movement according to the double arrow f45. The extractors 45 may be provided for instance as described in EP1719576.

As it is clearly apparent from figures 1 and 2, the positions that the lower clamping element 33 may achieve correlate with the heights HI and H2 of the insertion system for inserting the workpieces to be machined and the removal system for removing the machined workpieces, respectively. More in particular, the removal system for removing the machined workpieces is at a height H2 substantially corresponding to the lowest position taken by the lower clamping element 33. Vice versa, the height HI, at which the insertion system for inserting the workpieces to be machined is arranged, substantially corresponds to the maximum height achieved by the lower clamping element 33 when it has been completely raised. This correlation allows a correct movement of the workpieces in the loading and unloading steps, as explained below.

The cycle of loading, machining and unloading the workpieces will now be illustrated with specific reference to figures 1 and 2. PI indicates a workpiece to be machined, or blank, whilst P2 indicates a machined workpiece that shall be removed from the workpiece-holding slide 21.

A broken line in figure 1 indicates a possible position taken by the workpiece- holding slide 21 during machining the workpiece P blocked by the blocking member 19 through the jaws 19A or pairs of clamping elements 31, 33. For machining, the tools U are numerically controlled to move with respect to the workpiece P along the numerically controlled axes X, Y, Z, A, and C.

Once the workpiece has been machined, the workpiece-holding slide 21 is translated along the axis Y with a movement along the guides 23 towards the area 29 of loading the workpieces to be machined and unloading the machined workpieces.

In the meanwhile, in the loading and unloading position 29, an operator O has positioned a new workpiece PI to be machined putting it on the shelves 39. In this way it is not necessary for the operator to support the weight of the workpiece PI to be machined during the loading step.

The workpiece-holding slide 21 has moved towards the area of loading the workpieces to be machined and unloading the machined workpieces so as to allow the extractors 45 to pick up the machined workpiece P2 and transfer it in an area where it will be subsequently picked up, thus freeing the blocking member 19. To this end, the lower clamping element 33 is moved downwards until it achieves the height of the extractors 45. These latter can be therefore inserted below the machined workpiece P2 and can remove it with a movement according to the arrow f45. The machined workpiece P2 can be temporarily held by the extractors 45 in the position removed by the workpiece-holding slide 21, until the operator has finished the other operations described below for loading the workpiece PI to be machined and can therefore move the machined workpiece P2 away from the machining center 1.

Once the upper surface of the lower clamping element 33 has been freed, this latter can be raised to its upper position of maximum rise, where the upper surface of this lower clamping element 33 is approximately at the same height as the shelves 39 as shown in figure 2. Vice versa, the upper clamping element 31 has been raised at a sufficient height to allow the operator to transfer the workpiece PI to be machined, simply by pushing it, from the shelves 39 to the space defined between the opened clamping elements 31, 33. As the lower clamping element 33 is approximately at the height of the shelves 39 or slightly below them, it is not necessary for the operator to make an effort other than that required to push the workpiece PI, transferring it from the shelves 39 to the upper rest surfaces of the lower clamping elements 33, until to bring the workpiece to be machined PI to the position illustrated in figure 2.

The maximum rise position of the lower clamping element 33 is a reference position, to which all the machining coordinates of the workpiece to be machined PI are referred. As in this position of maximum rise the lower clamping element 33 can be a stop position defined by the vertical movement actuator of the same lower clamping element 33, this position can be repeated easily with high accuracy at each machining cycle, thus allowing to have an always correct reference of the workpiece to be machined PI, independently of the dimensions thereof in vertical direction.

Before machining a new workpiece PI to be machined, this shall be blocked in position. Blocking preferably occurs before starting the motion according to Y to transfer the workpiece-holding slide 21 from the area 29 of loading the workpieces to be machined and unloading the machined workpieces to the machining area below the operating head 5. To this end, the upper clamping element 31 may be lowered (arrow f31 in figure 2) with a vertical stroke depending upon the thickness (i.e. upon the vertical dimension) of the workpiece to be machined PI .

In advantageous embodiments, the upper clamping elements 31 may be provided with a coating 31 A made of an elastically yielding material for a better grip of the workpieces PI to be machined and the machined workpieces P2. The deformability of the coating 31 A does not have negative effects on the correct positioning of the workpieces to be machined, as these latter are positioned with respect to the operating head 5 by means of the lower clamping element 33 having high stiffness.

The embodiments described above and illustrated in the drawings have been explained in detail as examples of embodiment of the invention. It will be clearly apparent to those skilled in the art that modifications, variants, additions and omissions are possible, without however departing from the principles, the scope of the concept and the teachings of the present invention as defined in the attached claims. The scope of the invention shall be therefore determined exclusively based upon the widest interpretation of the attached claims, wherein these modifications, variants, additions and omissions are included within this scope. The terms "comprising" "to comprise" and the like do not exclude the presence of further elements or steps in addition to those specifically listed in a claim. The term "a" or "an" before an element, means or feature of a claim does not exclude the presence of a plurality of these elements, means or features. If a claim of a device claims a plurality of "means", some or all these "means" can be actuated by a single component, member or structure. The enunciation of given elements, features or means in distinct depending claims does not exclude the possibility of combining said elements, features or means together. Any reference numerals in the appended claims are provided to facilitate reading of the claims with reference to the description and to the drawing, and do not limit the scope of protection represented by the claims.

Claims

1. A machining center for working elongated pieces, comprising:

at least one operating head movable according to a plurality of numerically controlled axes;

at least one workpiece-holding slide movable between a working area and an area where workpieces to be machined are loaded on the workpiece-holding slide and machined pieces are unloaded from the workpiece-holding slide, and vice versa;

at least one blocking member carried by the workpiece-holding slide to block at least one workpiece on the workpiece-holding slide, wherein the blocking member comprises at least one lower clamping element and at least one upper clamping element that are both movable with respect to the workpiece-holding slide to block a workpiece to be machined there between;

an insertion system for inserting the workpieces to be machined on the blocking member;

a removal system for removing the machined workpieces from the blocking member;

wherein the insertion system of the workpieces to be machined and the removal system of the machined workpieces are arranged at two different heights and at least partially overlapping each other; and wherein the lower clamping element defines a stop for positioning the workpieces to be machined and is movable so as alternatively to move to the height of the insertion system of the workpieces to be machined and to the height of the removal system of the machined workpieces; and wherein the upper clamping element is provided with a clamping movement for clamping the workpieces, through which said upper clamping element is moved downwards towards the lower clamping element to block the workpiece between the upper clamping element and the lower clamping element.

2. Machining center according to claim 1, wherein the insertion system is arranged at a greater height than the removal system.

3. Working center according to claim 1 or 2, wherein the lower clamping elements is movable between two end positions, respectively a position of maximum rise and a position of maximum fall, one of said end positions being a reference position to which all the coordinates for workpiece machining are referred.

4. Machining center according to claim 1 or 2 or 3, wherein the lower clamping element, when arranged at the height of the insertion system, defines the positioning and reference stop.

5. Machining center according to one or more of the previous claims, wherein the upper and lower clamping elements are controlled and arranged so that the workpiece to be machined is transferred on the lower element when this latter is in the position defining the workpiece positioning and reference stop at substantially the same height as the insertion system.

6. Machining center according to one or more of the previous claims, wherein the upper clamping element comprises a coating made of yielding material.

7. Machining center according to one or more of the previous claims, wherein a surface for storing the machined workpieces is associated with the removal system.

8. Machining center according to claim 7, wherein the removal system comprises extractors that remove the machined workpieces from , the blocking member of the workpiece-holding slide and transfer them to the storing surface.

9. Machining center according to one or more of the previous claims, wherein the insertion system comprises shelves for supporting the workpieces before introducing them in the blocking member.

10. Machining center according to claim 7 and 9 or 8 and 9, wherein the lower clamping element is arranged and controlled so as to move to the height of the storing surface and to the height of the supporting shelves alternatively.

1 1. Machining center according to one or more of the previous claims, wherein the insertion system for inserting the workpieces to be machined comprises a rest surface which can be accessed by an operator and from which it is possible to access the lower clamping element, so that an operator can position a workpiece on the rest surface and transfer it by translating it along this rest surface onto the lower clamping element.