Abstract:
The miller comprises a pair of benches situated on both sides of a framework, in such a manner that on the upper crossbar is mounted, displaceable and guidable, a transverse support that carries a couple of vertical arms on which are mounted the corresponding tools, the arms being dispaceable towards one side or the other with respect to the support, while the tool that is borne by each of the arms may move upward/downward, as well as rotate, in such a manner that a combination of these movements produced by their corresponding motors allows simultaniously making two pieces that are symmetrical or the same, as well as effect simultanious digitalized work with one arm and milling with the other, after having mounted the corresponding tool on one arm and a digitalizer on the other.

Description:
OBJECT OF THE INVENTION 
     The invention refers to a double arm vertical miller capable of performing three movements according to the rectangular coordinates, &#34;X&#34;, &#34;Y&#34; and &#34;Z&#34;, as well as a rotational movement of each one of the two mills fitted on their respective arms. 
     The miller may simultaneously execute two symmetric parts that are mirror images of each other or two identical parts, as well as simultaneously execute milling or digitizing. 
     BACKGROUND OF THE INVENTION 
     Normally milling machines include an arm on which the corresponding tool for picking up shavings is mounted, being complemented with a second arm acting as a test probe, such that in this type of machine it is impossible to simultaneously execute the milling of two parts. 
     There also exists a type of milling machine with two heads, described in the Spanish utility model, with application No. 8802993, which characterizes the fact that one of the heads is mounted on a main shaft, which may be displaced upwards/downwards with respect to the machine frame, whilst the other head is fitted on a mobile frame. The mobile frame is guided on the main shaft with the possibility of axial sliding, with respect to the main shaft and to the mentioned first head. 
     This present invention provides an embodiment that relates to a combination of two independent millers rather than to a double head miller, since its advantages are those of two independent machines and not those of a functionally double machine. 
     DESCRIPTION OF THE INVENTION 
     This vertical milling machine, has a double arm, that is, two arms fitted over the ends of a support, with respect to which they may be displaced in a &#34;Y&#34; movement, said support also being able to be displaced according to an &#34;X&#34; movement with respect to the upper crossbar corresponding to a bridge fixed over the corresponding table of lower work, with the particularity that the arms mentioned first of all are holders for the work tools, in this case, of the mills, which may be displaced upwards/downwards, according to the third movement &#34;Z&#34;, as well as in a rotational direction, hence enabling two identical pieces to be machined, or even to carry out the machining of a piece by means of the tool fitted on one of the arms, and simultaneously to execute digitalizing by means of the corresponding digitalizer, fitted on the opposite arm. 
     The &#34;X&#34; movement of the upper support to the bridge will be made by means of a motor housed inside said support, preferably in correspondence with an area or intermediate point thereof, and which, for example, with a suitable reducer and pinion will work over a rack complementary to the corresponding guides which necessarily should incorporate the upper crossbar of the bridge to guide or displace this upper transverse support. 
     With respect to the &#34;Y&#34; movement of the respective vertical arms carrying the tools, or of a tool and the digitalizer, it will be done by means of a motor for each one of the arms, which arms are also fitted over guides in the respective transverse support. The motors for activating each arm will be located, for example, at each end of the transverse support. These motors are able to control movement of the respective arms in combination with, for example, associated screws and nuts 
     Regarding the &#34;Z&#34; movement, that is, the vertical displacements of the tool, it is due to the fact that these are fitted with the capability of axial displacement on the vertical arms, that is, they may move longitudinally inside said arms, being activated by means of the corresponding motors located on the upper end of the vertical arms or by means of a motor located on the central part and a set of gears. 
     Moreover, each mill or tool should be equipped with its corresponding rotational movement for the execution of the cut, a movement that will be provided by another motor located on the coupling part of the tool to the arm. 
     Unquestionably, all the referred motors to carry out the different movements will be located or housed inside the respective arms or parts, such that the miller as a whole will be a simple machine and through the combination of these movements and structure, the following advantages result: 
     It may execute the simultaneous machining of two symmetrical parts or two identical parts, with the advantages of time saving and quality. 
     It may simultaneously execute the digitalization with one of the arms, and the machining or milling of one part, with the other, likewise improving time and quality. 
     The arrangement of the arms and the combination of movements which may provided to the former, allow milling of all types to be executed, such as models, molds, scale layouts, valves, matrices and aeronautics. 
     The movements of the different parts or components of the machine considerably reduce the space, at the same time that two parts may be executed or one part and the simultaneous digitalization, occupying a space which was that required or required with one conventional machine to execute the work with a single arm. 
     As a further option a single motor can be used for the movement of both of the vertical arms. The single motor is directly coupled to one of the shafts in the transverse support, that corresponding to one of the tools and a first gear. The first gear, by means of a clutch device, may be directly connected to a second gear, which is at the end of the other shaft of the miller. Or the first and second gear may be used with the cooperation of an intermediate gear, such that when the clutchable first gear is isolated, only one of the tools of the miller operates, to produce a single part. When the clutchable first gear connects directly with the second gear of the other shaft, both tools simultaneously operate, to produce two mirror image parts since the first and second gears rotate in opposite directions. When the clutchable first gear engages the second gear with the cooperation of a third idler gear, both shafts rotate in a same direction, to obtain equal parts. 
     If the mentioned support is desired, fitted transversely over the intermediate framework, it may be finished at its ends by two stanchions associated to the work bench by means of guides facilitating its displacement, when the mentioned support is slid along the framework, such that the support is materialized in a second framework, installed with a sliding nature, over the intermediate and fixed framework. With the latter, vibrations are prevented and the machine working conditions are improved. 
     Over one of the stanchions participating in the mobile framework, a viewer may be created to control work development. 
     The bench may be divided in two parts, on both sides of the intermediate and fixed framework, and if it is desired that each one of the two benches are no longer fixed, becoming mobile with the collaboration of some guides and runners supported over them. In this way, maintaining the bridge fixed, the benches may be separately mobilized to obtain the different parts. 
     According to another of the characteristics of the invention, the vertical stemples of the support for the tools, which, in turn, slides over the intermediate and fixed framework, become dismountable, allowing, reducing the support stability, the possibility of machining parts of any size. 
     Returning to the mobility of the benches again, under each one of them, a motor may be placed over a screw-nut set, such that while the ends of the screw are fixed to the ends of the bench, the nut is fixed to the intermediate module thereof, hence becoming displaceable in one or other direction on rotating the said motor also in one or other direction. 
     According to another of the characteristics of the invention, the incorporation to the machine of fixed supports has been foreseen, in which a protractile boss acts, such that by means of bosses of said supports, the benches may be blocked, one at a time or simultaneously, specifically when two identical or mirror-image parts are being executed. 
     Finally, and according to another of the characteristics of the invention, the existence of a mobile support has also been foreseen with a fixed boss, entrusted with blocking the machine support, immobilizing it with respect to the bridge thereof, in turn, fixed, when necessary. This allows, for example, leaving one of the benches mobile and coupling a market turn-table to the other, at the appropriate distance, machining a crown of infinite external radius and internal radius depending on the width of the bench, it being possible to simultaneously execute another equal or different part by means of the other arm. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     To complement the description being made and with the purpose of understanding the characteristics of the invention better, a set of drawings which with an illustrative and non-limiting character is attached to this descriptive report as an integral part thereof, consist of the following: 
     FIG. 1 shows a schematic perspective view of one version of a double arm miller executed according to the principles of the invention. 
     FIG. 2 shows a schematic profile view, of the set of gears indicated by reference 8 in FIG. 2. 
     FIGS. 3, 4 and 5 show front views of the set of gears shown in FIG. 3 in positions: to obtain two identical parts, to obtain two mirror image parts and the milling of a single part, respectively. 
     FIG. 6 shows a similar view to that in FIG. 1, where the miller shows some modifications. 
     FIG. 7 shows a similar view to that in FIG. 6, where the two benches are partially sectioned showing part of their activation mechanism. 
     FIG. 8 is a view of the miller in FIG. 6, where the holding supports have been incorporated for the immobilizing bosses of the benches and the supports for coupling to the miller of a turn-table. 
     FIG. 9 schematically shows a plan view of the miller in FIG. 8 to which a turn-table has been coupled. 
    
    
     PREFERRED EMBODIMENT OF THE INVENTION 
     Viewing FIG. 1, it may be observed how the vertical miller shown incorporates a platform or work bench (1) on which is fitted transversely and in the center a fixed framework (2), which defines in its upper part a guide (3) for sliding movement of a support (4) along an &#34;X&#34; axis such movement being powered by a motor component (5). Respective end arms (6-6&#39;), slide over guides of the support (4) respectively powered by two end motors (7&#39;) or by an intermediate, single motor (7) by means of a set of gears (8), that will be described below, to obtain movement along a &#34;Y&#34; axis. Movement along the &#34;Z&#34; axis is obtained thanks to the tool holder heads (9), which are displaceable vertically inside said arms (6-6&#39;), power by respective motors (10), and (11), inside the arms (6-6&#39;), which motor also confer the tools (12) with the necessary rotational movement so that they may carry out their milling function. These tools are normally mills, but in a given case may be a digitalizer. 
     The support (4), at its opposite ends is interlocked to two stanchions (13-13&#39;). The stanchions (13-13&#39;) are provided at their lower end with means for coupling to the guides (14) at the margins and corresponding to the work bench (1). Thus the support (4) is a mobile framework offering a greater stability to the combination, absorbing vibrations and permitting a faster work rhythm. In turn, either of these stanchions (13) serves as a support for a viewer (15), allowing the development of the work being executed to be controlled. 
     Returning once again to the set of gears (8) and as may be especially observed in FIGS. 2 and 3, this consists of a main gear (16) which can slide over an extension (17) of the shaft (18) corresponding to one of the two halves of the support (4). The shaft 18 is powered by the motor (7), by means of the belt (19) or any other means of suitable transmission, such that this shaft (18) is kept in movement provided the motor (7) is running. 
     The other shaft (18&#39;), corresponding to the other half of the support (4) after a loaded transmission (20), terminates in a second gear (21) identical to the gear (16). The gear 16 is laterally dephased with respect to it, until a situation requires that the gears (16) and (21) engage. It is thus possible to engage and disengage gears 16 and 21 by of sliding the main gear (16) over the extension (17) of the shaft (18), between the extreme positions in FIGS. 4 and 5. 
     Specifically, in the engaged position shown in FIG. 4 for the gears (16) and (21), the movement is transmitted to the secondary shaft (18&#39;), in a direction opposite to that of the main shaft (18), hence obtaining the simultaneous machining of two mirror-image parts . In the position shown in FIG. 5, in which the gears (16) and (21) are disengaged, only the main shaft (18) moves, a work position corresponding to obtaining a single part. 
     In order and to simultaneously obtain two equal parts, the movements of the shafts (18) and (18&#39;) should be in the same direction. A idler third gear (22) is provided has on a walking beam (23), which beam (23) may be activated by any suitable device between the limit positions shown in a continuous and discontinuous plot in FIG. 2. Thus when a machining operation does not require engagement of the gear (2) it is held in the position shown in dotted outline in FIG. 2. Third gear (22) may be coupled to the gears (16) and (21), as an idler gear, according to the representation in FIG. 3, when said gears (16) and (21) are longitudinally disengaged, by which the intended transmission of movement is obtained from the main shaft (18) to the secondary shaft (18&#39;), with movement in a same direction, to obtain equal parts. 
     In FIG. 6, a similar view to that of FIG. 1 is shown, but with the novelty that the bench has been divided into two, with reference numbers (1) and (1&#39;), respectively. The components shown for one bench or the other have the same references as those shown in FIG. 1, with the difference that the reference numbers belonging to bench (1&#39;) are primed. 
     In FIG. 7, it may be seen that one of both of the stanchions (13-13&#39;) can be bypassed to avoid having them before with the purpose of an obstacle in some cases. For this purpose, the mentioned stanchions (13-13&#39;) can be rendered non-movable with the support (4), it then being possible to bypass them if the dimensions of the part to be machined so require (FIG. 7). 
     Regarding FIGS. 6 and 7, it may be observed that the benches (1-1&#39;) may be longitudinally non-movable, the end portion of the benches remains immobile. The benches (1-1&#39;) are structured of numerous telescopic and hollow modules, inside of which is a motor (25), which acts over a nut (26), fixed to the intermediate module of the corresponding bench (1-1&#39;), acting over a screw (27) between end bearings (28-28&#39;), fixed to the ends of the bench, as may be especially observed in FIG. 7. In this way, the operative sectors of the benches (1-1&#39;) may remain perfectly opposite to each other, as in the case of FIG. 6, when identical parts have to be machined, or may remain arranged in diametric opposition, as shown in FIG. 7, when symmetrical parts have to be prepared or they may adopt any other relative position when different parts have to be executed simultaneously. 
     Anyway, the benches (1-1&#39;) may be fixed with the help of fixed supports (29-29&#39;, 30-30&#39;) provided with a protractable shank (31) which may be housed in holes made in the corresponding edges of the benches (1-1&#39;). 
     Moreover, at the lower end of the vertical stemples (13-13&#39;), a fixed boss (32) is interlocked, such that to the two side bosses, two fixed supports (33-33&#39;) are coupled which permit, with the help of two turn-tables (34), consisting of market components and located at a suitable distance, as may observed in FIG. 9, to machine crowns of up to an infinite external radius and an internal radius depending on the width of the bench, as already has been said, it being possible to machine two crowns simultaneously, one on each side of the machine, or only one of said crowns and on the other side a part of any shape.