FR2684906A1 - Autolathe with tail stock - Google Patents

Abstract

The present invention relates to an autolathe with tail stock. The tail stock (14) carries two spindles capable of identically entraining two bars (6) to be machined which identical tools (58, 164, 72, 73, 88) machine simultaneously in order to produce mutually identical machined components (100).

Description

The present invention relates to a turning lathe of the type comprising
- a bench having a determined longitudinal direction and integrally comprising a transverse fan,
- a doll mounted movable in longitudinal translation relative to the bench, on a first side of the range with reference to the longitudinal direction,
a first spindle mounted movable for rotation about a first longitudinal axis with respect to the headstock and capable of receiving coaxially a first bar to be machined, temporarily attached to it,
a first guide barrel for the first bar in longitudinal translation and in rotation about the first axis relative to the fan, coaxial with the first spindle and in the longitudinal extension of that,
a first tool-holder means mounted to move in translation in a first transverse direction relative to the fan, on a second side of the latter with reference to the longitudinal direction, and capable of carrying at least one tool and of present it in the longitudinal extension of the first spindle,
- Motor means controlled according to a machining to be carried out to cause controlled movements of longitudinal translation of the headstock relative to the bench, of rotation of the first spindle around the first axis relative to the; headstock, and of translation of the first tool-holder means in the first transverse direction relative to the fan.

 - means of command and control of the motor means according to the machining to be carried out.

 Generally, in the above as in the following, it is meant by the fact that a tool is presented in the longitudinal extension of a spindle the fact that it occupies a position such that, if a bar is engaged with this spindle and crosses the fan through the associated barrel, it interferes with this bar to carry out machining, whatever the design and orientation of the tool for this purpose and in particular whether it is transverse or longitudinal , parallel to the corresponding axis or coincident with it, fixed or movable relative to the corresponding tool holder means.

 Such turning turns are well known, and marketed for example by the Applicant under the references K'MX 20 and 26, in a version in which the spindle and the guide barrel are respectively unique and in which the first tool holder means is completed by a second tool-holder means movable in translation in a second transverse direction relative to the fan, on the second side thereof, and capable of carrying at least one tool and of presenting it in the longitudinal extension of the first pin then unique. This makes it possible to carry out simultaneously, on the same bar, two compatible machining operations in that they must be carried out at the same speed of rotation of the bar around the first axis under the effect of the spindle and, optionally, of longitudinal translation. of the bar under the effect of the movable headstock, or in that they require the bar to be stopped in the same determined position both angularly with reference to the first axis and with longitudinal translation; it is thus possible to save time for the production of a part from the bar, for example by authorizing simultaneous turning with a roughing tool, on the one hand, carried by the first tool holder means, and by a finishing tool, on the other hand, carried by the second tool holder means.

 However, it appeared desirable to increase the rate of such a turning lathe in terms of the number of parts produced per unit of time and for example per hour.

 To this end, it is certainly possible to juxtapose two of these known turning turns, which makes it possible to double the rate if we consider these two turns together but has a number of particularly sensitive drawbacks.

 One of these drawbacks resides in the outright doubling of the investment to be made and another of these drawbacks resides in the size, also doubled, of an installation comprising two turning turns thus juxtaposed; in addition, insofar as it is necessary to carry out separately the commands for the movements of longitudinal translation of the dolls of the two turning turns relative to the respective bench, of joint rotation of the bars and pins around the respective first axis relative to the respective headstock, of transverse translation of the first and possible second tool-holder means with respect to the fan, an installation grouping two turning turns of known type requires significant labor time, in fact double that required only one of these turning turns.

The object of the present invention is to remedy these drawbacks and, to this end, the present invention provides a turning lathe of the type indicated in the preamble, characterized in that it comprises
a second spindle mounted movable for rotation about a second longitudinal axis with respect to the headstock and capable of coaxially receiving a second bar to be machined, temporarily attached to it,
a second guide barrel for the second bar in longitudinal translation and in rotation about the second axis relative to the fan, coaxial with the second spindle and in the longitudinal extension of the latter,
a second tool holder means mounted movable in translation in a second transverse direction relative to the fan, on said second side of the latter, and capable of carrying at least one tool identical to said tool of the first tool holder means, and to present it in the longitudinal extension of the second spindle,
kinematic coupling means on the one hand between the first and second pins, with the longitudinal translation joint with the headstock relative to the bench and with the rotation around the first and second axes relative to the headstock, and on the other hand share between the first and second tool-carrying means, in translation along the first and second transverse directions, so as to present identical tools simultaneously in the longitudinal extension of the first and second spindles and to simultaneously machine identical parts from the first and second bars.

 In a space barely larger than that of a single-spindle turning lathe, the lathe according to the present invention allows a much higher rate because of the possibility of carrying out simultaneously, on two bars, all the necessary machining to the realization of a respective piece, identical from one bar to another.

 A turning lathe according to the invention remains however much less expensive than two turning lathe working on a single bar at the same time, because of the possibility of using common means to carry out the machining of the two bars including with regard to machining command and control means. Thus, it is easily understood that a turning lathe according to the invention could comprise a single bench, a single fan carrying the first and second guide guns, a single movable headstock carrying the first and second pins, as well as common motor means , controlled as a function of the same machining to be carried out, that is to say by action of an operator at the level of a single command and control panel and / or by implementing a memorized machining program also in electronic command and control electronics, to cause controlled movements of longitudinal translation of the headstock relative to the bench, rotation of the first and second pins around the first and second axes relative to the headstock, and translation of the first and second tool holder means in the first and second transverse directions relative to the fan. It is also easily understood that the kinematic coupling means on the one hand between the first and second pins, with the longitudinal translation joint with the headstock relative to the bench and with the rotation around the first and second axes relative to the headstock, and on the other hand between the first and second tool-carrying means, in translation along the first and second transverse directions, are much less costly than doubling the driven motor means and their control and command means, which entails the aforementioned juxtaposition of two turning turns of known type.

 These advantages are found even if, preferably and known in itself in the case of single-spindle turning lathes, provision is made for the first and second guide guns to be mounted for rotation in the fan respectively around the first axis and around the second axis; indeed, advantageously provision is made in this case for kinematic coupling means of the first and second guide guns with the first and second pins for rotation about the first and second axes, these kinematic coupling means being able to be produced in a particularly simple as well as the aforementioned kinematic coupling means between the first and second spindles and between the first and second tool holder means, respectively.

 In a manner known in itself in the case of single-spindle turning lathes, the first and second tool holder means may advantageously include first and second tool turrets capable of carrying several respective tools simultaneously, identical for the first and second turrets specifically of the present invention, and it is then provided that the first and second turrets are indexable around a respective longitudinal axis to present respectively in the longitudinal extension of the first spindle and in the longitudinal extension of the second spindle a identical determined tool; the controlled motor means then comprise for this purpose means for causing identical controlled indexing of the first and second turrets around their longitudinal axis.

 Such a design of the first and second tool holder means makes it possible to benefit from the known advantages of productivity gain linked to the possibility of successively carrying out several different machining operations on the same work station.

 The transverse size of the turning lathe according to the invention remains however little increased compared to that of a turning lathe of known type, comprising first and second tool-carrying means in particular produced in the form of two turrets however associated with a single spindle if, preferably and moreover known in itself in the case of such a single-spindle turning lathe, the first and second transverse directions are combined and the first and second tool-holding means disposed respectively on either side of an assembly formed in the case of a turning lathe according to the invention by the first and second guide guns, replacing a single guide barrel of a single-spindle turning lathe of l 'Prior art.

 It will be observed that the desire to keep a transverse size as small as possible in a turning lathe according to the invention leads to providing the first and second tool holder means, in particular in the form of a respective turret, in a single associated copy respectively to the first spindle or the second spindle.

 This certainly does not make it possible to benefit from the possibilities of successive presentation of a large number of different tools, and for example of six or eight different tools, respectively in the longitudinal extension of the first spindle and in the longitudinal extension of the second spindle , that in a reduced way in comparison with a single-spindle turning lathe, on which the presence of two turrets allows comparatively to double these possibilities, by additionally offering the possibility of simultaneously presenting two tools towards or along the first axis then single.

 However, this limitation is not really a hindrance insofar as it is possible to provide additional tool-carrying means which, without constituting turrets, nevertheless offer interesting additional machining possibilities.

 Thus, if the complexity of the machining operations requires it, a turning lathe according to the invention can comprise a third tool-holder means mounted movable in longitudinal translation relative to the bench, on the second side of the fan, and capable of carrying at least one pair of identical tools disposed respectively in the longitudinal extension of the first spindle and in the longitudinal extension of the second spindle, in which case the controlled drive means comprise means for causing controlled movements of longitudinal translation of the third tool holder means in relation to the bench.

Naturally, this third tool holder means can work simultaneously with or alternately with the first and second tool holder means. This third tool holder means can also carry a pair of take-up pins arranged respectively in the longitudinal extension of the first spindle and in the longitudinal extension of the second spindle, for a purpose which will become apparent from the following description; then, preferably, the controlled motor means comprise controlled means for synchronized drive of the pins for resumption of rotation on themselves relative to the third tool-carrying means.

 Like the first and second tool holder means, this third tool holder means can offer the possibility of carrying out successively different machining operations simultaneously on the first and second bars if, in accordance with a preferred embodiment, this third tool holder means itself a third tool-holder turret indexable about a longitudinal axis coplanar with the first and second axes and equidistant from the latter, the third tool-holder turret being capable of carrying several pairs of mutually identical tools, respectively said pair return pins, arranged mutually symmetrically with respect to the longitudinal axis of the third turret, in which case the controlled drive means comprise means for causing controlled indexing of the third turret around its longitudinal axis so as to present tools simultaneously identical or the recovery pins in the longitudinal extension of the first and second pins.

 Other embodiments of the third tool holder means, however, offer this possibility of successively carrying out different machining operations simultaneously on the first and second bars.

 Thus, according to a variant of this third tool-carrying means, the latter comprises a tool-carrying carriage mounted movable in translation in a third transverse direction relative to the bench and capable of carrying several pairs of mutually identical tools, respectively said pair of return pins, mutually juxtaposed in a fourth transverse direction parallel to a plane defined by the first and second axes, said pairs of tools, respectively said pair of return pins, being mutually juxtaposed in the third transverse direction and the third transverse direction intersecting said plane, and the controlled motor means comprise means for causing controlled movements of translation of the tool carriage in the third transverse direction relative to the bench so as to present simultaneously identical tools or the recovery pins in the lon extension gitudinal of the first and second pins; preferably, the third transverse direction is perpendicular to said plane.

 According to another variant of the third tool holder means, the latter comprises a tool carriage mounted movable in translation in a fourth transverse direction relative to the bench, and capable of carrying several pairs of mutually identical tools, respectively said pair take-up pins, mutually juxtaposed in the fourth transverse direction, the fourth transverse direction being parallel to a plane defined by the first and second axes, and the controlled motor means comprise means for causing controlled movements of translation of the tool carriage according to the fourth transverse direction relative to the bench so as to present simultaneously identical tools or the recovery pins in the longitudinal extension of the first and second pins.

 In addition to the third tool holder means or as a replacement for the latter, a twin-spindle turning lathe according to the invention may include a fourth tool holder means mounted movable in translation in a third transverse direction relative to the fan. , on the second side thereof, and capable of carrying at least one pair of mutually identical tools, or means for supporting the bars, mutually juxtaposed in a fourth transverse direction parallel to a plane defined by the first and second axes, the third transverse direction being secant from said plane and for example perpendicular thereto; the controlled motor means then comprise means for causing controlled movements of translation of the fourth tool-carrying means in the third transverse direction relative to the fan, so as to present identical tools simultaneously, or the means for supporting the bars, in the longitudinal extension of the first and second pins.

 This fourth tool holder means on the one hand ensures support for the bars if the workpieces have a large longitudinal dimension, resulting in a significant longitudinal overhang of the bars relative to the range, second side of the latter, and on the other hand to perform on each bar an additional machining operation simultaneously with the machining carried out respectively by the tools of the first and second tool-carrying means and by the tools of any third tool-carrying means , or alternately with these machining operations.

 It is even possible to carry out thus, successively, two machining operations, or more than two machining operations, by means of the fourth tool-carrying means if the latter is capable of carrying a plurality of pairs of mutually identical tools, mutually juxtaposed in the fourth direction transverse while said pairs of tools are mutually juxtaposed in the third transverse direction; under the action of the controlled motor means, it is possible during the machining carried out by the tools carried by the first and second tool-carrying means and possibly by the tools carried by the third tool-carrying means, or alternately with this machining, present in the longitudinal alignment of the first and second spindles, that is to say bring into contact with the first and second bars, any of the pairs of identical tools of the fourth tool holder means.

 The tools carried by the fourth tool-carrying means, such as the tools carried by the first, second and third tool-carrying means, can be of any desired design, and of any desired orientation, compatible with the possible relative displacement (s) between the carrying means corresponding tools and the first or second bars, provisionally integral with the first and second pins respectively; it can thus be in particular stationary or driven tools, in particular rotation on themselves, relative to the corresponding tool holder means when they are in service, transverse or longitudinal tools, parallel to the first and second axes or merged with these, respectively, to perform end machining such as drilling, reaming, tapping, these examples being in no way limiting.

 In addition, when a lathe according to the invention simultaneously comprises the third tool holder means, in the form of a third turret comprising the aforementioned pair of recovery pins, and the fourth tool holder means, it is possible to make cooperate the third and fourth tool-holder means to complete the machining of parts already separated from the first and second bars after partial machining by the tools carried by the different tool-holder means, by carrying these parts by means of the take-up pins and by machining them by means of tools carried by the fourth tool-carrying means while other parts, for their part still integral with the first and second bars, undergo all or part of the aforementioned partial machining, in particular by means of the tools first and second tool holder means; production rates can be considerably increased.

 A preferred embodiment of the invention, for this purpose, is characterized in that the fourth tool holder means is capable of carrying at least one pair of mutually identical tools facing the third turret, arranged mutually symmetrically by relative to a longitudinal axis of the fourth tool holder means, coinciding with the longitudinal axis of the third turret in a privileged position of the fourth tool holder means, in that the means for causing a controlled indexing of the third turret are suitable for simultaneously place the take-up pins, in a controlled manner, in a take-up position in which they are arranged respectively along the first axis and along the second axis and in at least one machining position in which they are placed in the respective longitudinal extensions tools of said pair, while the fourth tool holder occupies said privileged position principal point; it will be noted that one could also use tools carried by the first and second tool-carrying means to complete the machining of parts already partially machined, carried by the return pins, it being understood that the third tool-carrying means, carrying these recovery pins, could be constituted not only by a turret but also in a different way and for example in the form of a carriage as indicated above.

 Whether the tools thus used for machining parts carried by the take-up pins belong to the fourth tool-carrying means or to the first and second tool-carrying means, the machining which they carry out can be accompanied by a rotation of the recovery on themselves or a fixity of these recovery pins, suitably indexed relative to the third tool holder means.

 Preferably, each of the aforementioned tool-carrying means comprises means for individual adjustment of the tool or of the corresponding tools respectively, in order to make it possible to correct possible differences in wear and tear between tools, in principle identical, intended to machine the first and second bars; these adjustment means can be manual and actuated by an operator observing differences between the dimensions of the parts machined from the first and second bars, but it is also possible to provide for automatic take-up of the wear clearance, which however has the drawback considerably increase the complexity of a turning lathe in accordance with the present invention without corresponding to a related advantage. When the aforementioned differences in wear translate into differences in the longitudinal dimensions of the machined parts, provision may be made, with a view to their correction, for means of relative longitudinal adjustment of the first and second pins, preferably in the form automatically controlled by function of the machining to be carried out in order to have a specificity of adjustment as a function of the tool used at any given time in a particularly simple manner, it can be provided for this purpose that the first spindle is longitudinally fixed relative to the headstock movable and that the relative longitudinal adjustment means of the first and second spindles comprise longitudinal adjustment means of the second spindle relative to the movable headstock.

 It will also be observed that insofar as a turning lathe according to the invention simultaneously practices identical machining operations on the two bars, in principle at the same transverse level, a possible lack of transverse alignment of the two bars before their machining may require an initial lengthening operation by cutting off that of the bars which exceeds the other, in a longitudinal direction going from the first and second pins towards the first and second guide guns, or by cutting up the two bars at one same transverse level while they are also supported at the same transverse level, towards the rear with reference to said longitudinal direction, in bar advance means known in themselves, associated with the first and second spindles and controlled in permanent synchronism in the context of the present invention; this has the drawback of causing on the one hand an additional machining operation, and on the other hand a loss of material due to the production of a fall.

 To avoid such a possibility, a turning lathe according to the invention preferably comprises means for mutual transverse alignment of the first and second bars prior to their machining.

 In a particularly simple manner, these transverse alignment means can comprise at least one stop piece having a flat stop face and mounted movable relative to the fan, on the first side of the latter, between a position in which the piece stopper is interposed between the first and second pins, on the one hand, and the first and second guide guns, on the other hand, and in which the stopper face cuts perpendicularly the first and second axes while being turned towards the first and second pins, and a position in which the abutment piece clears the respective longitudinal alignments of the first pin and the first guide gun, on the one hand, and the second pin and the second guide gun, on the other go.

 The operation of mutual transverse alignment of the first and second bars prior to their machining can be controlled manually or automatically and consists in first placing the stop piece in the first of the above positions then causing the first and second bars, engaged for this purpose in mutually independent bar advance means, known in themselves, until the two bars abut against the abutment face in a longitudinal direction going from the first and second pins towards the first and second guide guns; the first and second pins, with respect to which the first and second bars were initially free to slide longitudinally, are then tightened respectively on the first bar and on the second bar, so as to ensure mutual securing of the first bar and the first spindle, on the one hand, and the second bar and the second spindle, on the other hand, then the abutment piece is brought into the aforementioned second position. Then, by a longitudinal translational movement of the headstock in relation to the bench, the first and second bars mutually aligned transversely are engaged in the first and second guide guns, respectively, while maintaining their mutual transverse alignment, which they will keep in principle during the machining of successive parts from each of them; the bar-advance means are in fact then controlled in synchronism in the same way as the first and second spindles; however, the operation of mutual transverse alignment of the bars could if necessary be repeated between the respective machining of two successive pieces from each of them, after a movement of recoil of the bars intended to clear a passage for the piece of stop.

 At the end of the machining of a respective part in each bar, and taking into account that it is preferable not to drop the machined parts, detached from the bars at the end of the machining by transverse cutting by means of parting-off tools carried by one or other of the aforementioned tool-carrying means, in order not to risk damaging either these parts, or the tools possibly carried below the parts, in particular by the possible fourth tool-carrying means, it is preferably provided that a turning lathe according to the invention comprises means for taking up the parts machined from the first and second bars.

 These recovery means may advantageously include first and second clamps mounted movable relative to the fan, on the second side thereof, between a position for taking charge of a respective part, in which the first and second clamps are disposed respectively along the first axis and along the second axis, and a discharge position; the controlled motor means then comprise means for causing an evolution of the sleeves reach or are in the evacuation position. Depending on the case, the ejection pushers can be fixed relative to the bench so that the ejection of the machined parts out of the sleeves results only from a longitudinal translation of the latter towards their evacuation position from their support position, or be movable in longitudinal translation relative to the bench, under the action of said controlled motor means, to eject the machined parts out of the sleeves while the latter occupy their evacuation position; in one case as in the other, the movements of passage of the sleeves from one to the other of the pick-up and evacuation positions, respectively, is preferably carried out by simple longitudinal translation of the sleeves relative to the bench but, in particular for reasons of compatibility with the presence and operation of the third tool holder means which, moreover, could carry said ejection pushers to align them if necessary with the sleeves, under the action of said motor means controlled, this longitudinal translation can be accompanied by other movements, for example similar to those of the aforementioned clamps, without departing from the scope of the present invention.

 Other characteristics and advantages of a turning lathe according to the invention will emerge from the description below, relating to a nonlimiting exemplary embodiment, as well as from the appended drawings which form an integral part of this description.

 - Figure 1 shows a perspective view of a turning lathe according to the present invention.

 - Figure 2 shows a partial view, in perspective, of this turning lathe without its protective covers.

 - Figure 3 is a diagram of this tower, seen from above.

 - Figures 4 and 5 show details of this turn, in directions identified by arrows 4 and 5 respectively in Figure 2.

 - Figures 6 and 7 illustrate the adjustable mounting of two different types of tools on one of the first and second turrets acting as first and second tool holder means, in section through a plane including the longitudinal indexing axis of this turret.

 - Figures 8 to 10 illustrate, in a sectional view through a vertical plane passing through one or the other of the first and second axes, constituting the axes of rotation of the first and second pins, a process of transverse alignment of the first and second bars before provisionally joining them with the first and second pins, respectively, then machining.

 FIG. 11 shows a detailed diagram of the third tool-holder turret, forming the third tool-holder means, in a longitudinal direction indicated by an arrow XI in FIG. 2.

 FIG. 12 shows a view of the fourth tool holder means, in a longitudinal direction opposite to direction XI and identified by an arrow XII in FIG. 2.

 - Figure 13 shows, in a view similar to that of Figure 4, a mounting variant of the first and second pins relative to the movable headstock.

 - Figures 14 and 15 illustrate, in views similar to that of Figure 2, two alternative embodiments of the third tool holder means.

 - Figure 16 illustrates, in an exploded view but also similar to that of Figure 2, different possibilities of mounting tools on the fourth tool holder means.

 - Figure 17 illustrates, in a view similar to that of Figure 2, the cooperation of a third tool holder means produced in the form of a turret and tools carried by the fourth tool holder means.

 - Figure 18 illustrates, in a view similar to that of Figure 2, an alternative embodiment of the means for taking up the machined parts.

As shown in Figure 1, the turning lathe 1 according to the invention comprises, like a traditional turning lathe
- a lower frame or base 2 fixed to the ground not shown
- an upper cowling 3 mounted in a partially removable manner on the lower frame 2 and normally closed when the turning lathe 1 is in service
- A command and control panel 4, placed at eye level so as to be visible when the upper cowling 3 is closed, is for example mounted for this purpose on a fixed part of this upper cowling 3
- A cabinet 5 housing a command and control electronics 16, shown diagrammatically in FIG. 3, in functional connection on the one hand with the command and control panel 4 and on the other hand with different components of the turning lathe 1 which will be described later to command and control, typically of the invention, the simultaneous machining of two mutually parallel bars 6, visible in other figures; the cabinet 5, fixed relative to the ground, is for example juxtaposed to the lower frame 2
an automatic interlocking device 7 formed, in a characteristic manner of the present invention, of two automatic bar feeders 8 of the traditional type, mutually juxtaposed and fixed to the ground; these bar feeders 8, commercially available, are not characteristic of the present invention except that they are controlled in synchronism, in a manner easily conceivable by a person skilled in the art, and will therefore not be detailed .

 Inside the cover 3 assumed to be closed, the lower frame 2 carries the components which will now be described with reference to FIGS. 2 to 12, in general, and to FIGS. 13 to 18, relating to variants, expressly indicated.

 In particular, as shown more particularly in FIG. 2, the lower frame 2 integrally carries a main bench 9 and an auxiliary bench 10 horizontal having the same longitudinal direction, horizontal Z and mutually juxtaposed longitudinally so as to present the same longitudinal plane, vertical 18 of respective symmetry which, as will emerge from the following description, forms a plane of symmetry either respective or mutual for most of the components of the turning lathe 1 housed inside the cowling 3.

 It will be noted that, secured to each other by respective attachment to the lower frame 2, the two benches 9 and 10 behave as an integral whole and could consist of a single piece; their dissociation nevertheless makes it possible to present the turning lathe 1 in modular form, the auxiliary bench 10 being optional and its presence being linked only to a desire to increase the possible machining operations on the lathe turning 1, it that is to say in the same workstation.

 In a transverse end zone facing the auxiliary bench 10, the main bench 9 integrally carries, projecting upward, a transverse fan 11 which could if necessary also be made at least partially in one piece with the bench main 9.

 If we consider as a reference direction a direction 12 of the longitudinal direction Z going from the main bench 9 to the auxiliary bench 10, the transverse fan 11 is thus placed in a front end zone of the main bench 9 and, in rear of the fan 11, this main bench 9 integrally carries longitudinal guide rails 13, in longitudinal translation without any other possibility of relative displacement, for a headstock 14 thus movable longitudinally, in approach and in distance, relative to range 11.

 To cause controlled movements of approximation or longitudinal distance of the movable headstock 14 relative to the fan 11, the frame 2 integrally carries an electric motor 15 acting on the headstock 14 by means of a ball screw 21 with a longitudinal axis 108 or an equivalent device and the starting of this motor 15 with a view to a longitudinal translation of the movable headstock 14 in one direction or the other relative to the fan 11 and the stopping of the motor 15 are controlled by the command and control electronics 16 housed in the cabinet 5, according to a machining to be carried out, under the command and control of the control panel 4.

 This assembly of the movable headstock 14 and this mode of control of its longitudinal translation in one direction or the other relative to the fan 1 1 are common to the headstock turning lathe dollies of the prior art and do not require this makes no further description.

It will be noted that although the motor 15 has been illustrated in the direct longitudinal extension of the ball screw, itself arranged along the plane 18 and interposed between the slides 13, on the block diagram of FIG. 3, prefer to have the motor 15 next to the main bench 9, along one of the slides 13, and connect it to the ball screw 21 via a constant velocity transmission 22 for example with belt and pulleys, as indicated in Figure 4.

 So this time characteristic of the present invention, the movable doll 14 has internally two pairs 17, mutually symmetrical with respect to the plane 18, of guide bearings, exclusively for rotation about a respective longitudinal axis 19 with respect to the doll mobile 14, of a respective spindle 20 capable of receiving coaxially, in an integral but removable manner, a respective work bar 6 provided by one, respective, of the bar feeders 8 themselves arranged along the axes 19; the mutual symmetry of the pairs of bearings 17 with respect to the plane 18 also implies mutual symmetry of the axes 19 arranged in the same horizontal plane 53, of the pins 20, of the bars 6 and of the bar feeders 8 with respect to this plane 18.

 The design of each of the pins 20 is known in itself and the movements of these pins 20 corresponding respectively to their attachment to the corresponding bar 6 or to mutual release are controlled simultaneously and controlled by the command and control electronics 16 , under the command and control of table 4, identically to the way in which the corresponding movements of the single spindle of a traditional turning lathe with movable headstock are controlled.

 To ensure, in accordance with the present invention, a driving of the pins 20 to rotate in the same direction around their respective axis 19 relative to the movable headstock 14 or a stop of this rotation in a perfectly synchronous manner, the two pins 20 are connected by a respective constant velocity transmission 23, for example belt and pulleys, to a first output shaft 24, of longitudinal axis 104, of an electric motor 25 carried integrally by the movable headstock 14, for example along the plane longitudinal 18, under the pairs of bearings 17, inside a longitudinal opening 101 that the main bench 9 presents between the slides 13.

 The starting of the motor 25, at a speed of rotation of its output shaft 24 as a function of machining determined to be carried out on the two bars 6, as well as its stopping are commanded and controlled by the command and control electronics 16 and by the command and control panel 4.

 The angular position, around the axis 19, in which the two bars 6 are immobilized when the engine 25 is stopped, being of importance for the realization by means of the turning lathe 1 of certain machining operations not corresponding to a turning, means coding 26 are provided to identify at any time the angular position of the two bars 6 around the respective axis 19 and to transmit it to the command and control unit 16 and to the command and control panel 4. In the illustrated example, in which the first output shaft 24 of the motor 25 is turned towards the rear and connected to the pins 20 by the constant velocity transmissions 23 behind the mobile headstock 14, the coding means 26 are placed in a front zone of the movable headstock 14, between the pairs of bearings 17, along the longitudinal plane 18, and have an input shaft 32 of longitudinal axis 33 arranged for example in this plane 18, connected by a transmi constant velocity position 27, for example with belt and pulleys, to an intermediate shaft 28 projecting forward relative to the movable headstock 14, inside which this intermediate shaft 28 is mounted for rotation around a longitudinal axis 29 disposed in the longitudinal plane 18, with no other possibility of relative rotation; the intermediate shaft 28 is itself connected by a constant velocity transmission 30, for example with belt and pulleys, to a second output shaft 31 of the motor 25, which shaft 31 is directly integral with the first output shaft 24 of which it constitutes the coaxial extension forward, opposite the motor 25.

 The respective transmission ratios of the constant velocity transmissions 23 and 30 are identical, so that the intermediate shaft 28 rotates around the axis 29 at the same angular speed and in the same direction as the pins 20, i.e. -to say that the bars 6, around the corresponding axis 19 respectively, and the constant velocity transmission 27 ensures a transmission ratio of 1/1 so that the input shaft 32 of the coding means 26, mounted at the rotation in the latter around the longitudinal axis 33, rotates rigorously at the same angular speed and in the same direction as the bars 6 and that its angular position, around the axis 33, is therefore representative of the angular position of the bars 6 around the respective axis 19.

 In addition to its role as a transmission intermediary between the output shaft 31 of the motor 25 and the input shaft 32 of the coding means 26, the intermediate shaft 28 plays the role of a power take-off for the purpose of l synchronous drive with the pins 20, to rotation around the axes 19, of two rotating barrels 34 provided for guiding the bars 6 on the one hand to rotation around the respective axis 19 and on the other hand to the translation along this axis inside the fan 11.

More precisely, in the longitudinal alignment of each of the spindles 20, the fan 11 integrally carries a respective bearing 35 of a type suitable for guiding the relative rotation around the corresponding axis 19, without the possibility of relative translation in one direction or the other along this axis, for a respective one of the barrels 34 suitably designed to cooperate for this purpose with the corresponding bearing 35 respectively, in a manner easily determinable by a
Tradesman; in a known manner in the field of lathes with movable headstock and single spindle of the prior art, each of the barrels 34 is further internally machined so as to receive the bar 6 respectively corresponding to the free longitudinal sliding while not offering it on the other hand no possibility of transverse movement, except within the limits imposed by this possibility of longitudinal sliding.

 Behind the fan 11, each of the barrels 34 is connected by a constant velocity transmission 36, for example with belt and pulleys, to a longitudinal input shaft 37 coaxial with the intermediate shaft 28 and itself connected to the latter by a constant velocity transmission compatible with the movements of approximation or longitudinal distance of the movable headstock 14 relative to the fan 11, and for example produced in the form of external grooves, longitudinal of the shaft 37, cooperating with grooves internal, longitudinal (not shown) of the shaft 28 then produced in the form of a hollow shaft as shown schematically in 39. Thus, whatever the longitudinal position of the movable headstock 14 relative to the fan 11 , each barrel 34 is rotated about the axis 19 respectively corresponding to the same speed as the spindle 20 respectively corresponding and in the same direction as the latter if the m otor 25 operates, or is immobilized against such a rotation, in the same way as spindle 20, if the motor 25 is stopped.

 To firmly immobilize the barrels 34 and the pins 20, and with them the bars 6, against a rotation about the corresponding axis 19 respectively when the motor 25 is stopped, in particular during machining of the bars 6 other than a turning, temporary locking means 40, commanded and controlled by the command and control electronics 16 and by the command and control panel 4, are provided for example at the level of the shaft 37, being understood that such means could also be provided at any shaft, having an angular position representative of the angular position of the pins 20 and bars 6 around the respective axis 19, in particular in a simplified version of the turning lathe 1 in which the barrels 34 would be driven in rotation not by kinematic connection with the motor 25 also ensuring the driving of the pins 20 and bars 6, but simply by contact with these bars es 6 as in the case of traditional turning lathes with movable headstock and single spindle.

In the example illustrated, these temporary locking means 40 comprise
a pinion 41 coaxial with the shaft 37 and integral with the latter, this pinion 41 having a regular external toothing 42, the teeth of which are, for example, angularly offset by 5, or 3, or 1 "
- An electromagnet 43 carried integrally by the fan 11, in a radial direction 44 relative to the axis 29 and at the pinion 41; this electromagnet 43 comprises in the direction 44 a rod 45 projecting towards the pinion 41 and carrying itself in an integral manner, directly facing the toothing 42 thereof, a wedge 46 capable of engaging between two teeth 42 to immobilize the shaft 37 to rotation about the axis 29 relative to the movable headstock 11, or to retract in the direction of a radial distance relative to the axis 29 to release the shaft 37 vis-à-vis a rotation around this shaft 29 relative to the movable headstock 11, by exit or entry of the rod 45 of the electromagnet the control of the electromagnet 43 for this purpose is naturally provided by the command and control electronics 16 and the command and control panel 4 simultaneously with the stopping and starting of the motor 25.

 It is easily understood that the immobilization or the release of the shaft 37 with respect to a rotation around the shaft 29 relative to the fan 11 also ensures the immobilization or the release of the pins 20, guns 34 and bars 6 with respect to a rotation about the respective axis 19, with respect to the movable headstock 14, as well as the immobilization or the release of the input shaft 32 coding means 26 around its axis 33.

 Naturally, in a manner known in itself, the bars 6 during machining form a cantilever in front of the fan 11, and in particular of the guide barrels 34, and the value of this door-to- false, measured longitudinally between a front transverse end 47 of each bar and a flat, transverse, reference face which can for example constitute a front face 48 of the fan 11, must be identical for the two bars 6 in order to allow the machining of identical parts in the latter.

 When the parts have already been machined from the bars 6, this identity results from the machining itself, and more precisely from the fact that the parts machined simultaneously in the two bars 6 and then detached from the latter by cutting off have a longitudinal dimension determined, identical, and of the synchronized operation of the bar feeds 8 associated with the two pins 20, but a mutual transverse alignment operation of the front ends 47 of the bars 6 should preferably be carried out before machining a first part in each bar 6, in order to avoid differences in longitudinal dimension between the parts machined first in the bars 6 and the lengthening operations, with the creation of a drop, which would result from a possible initial longitudinal offset between the two bars 6.

 To allow this transverse alignment to be carried out before the machining of a first part in each bar 6, the turning lathe 1 comprises, in the preferred embodiment which has been illustrated, transverse alignment means 49 carried by the fan 11, immediately behind the guide barrels 34.

 More specifically, these transverse alignment means 49 comprise, on a flat, rear transverse face 50 of the fan 11, above the guide barrels 34, an electromagnet 51 having an axis 52 arranged perpendicular to the plane 53 of the two axes 19, and more precisely along the longitudinal plane 18.

 Along this axis 52, the electromagnet 51 has a rod 107 projecting downward, which rod 107 carries integrally, by a lower end, a stop piece 54 which can be changed by means of the electromagnet 51, that is to say by bringing the rod 107 in or out of it, between a comparatively high position in which the part 54 is entirely offset upwards, transversely with respect to the longitudinal alignment of the barrels 34 and of the pins 20 to allow the bars 6 to access the guide barrels 34, as shown in FIGS. 5 and 8, and a comparatively low position in which the abutment piece 54 is inserted between the barrels guide 34 and the pins 20 for opposing the bars 6 a stop forward with respect to the fan 11.

 So that this stop translates into a mutual transverse alignment of the ends 47 of the bars 6, the stop piece 54 presents towards the rear is, in a manner not illustrated, a flat transverse face which cuts the two axes 19 perpendicularly when the piece 54 occupies its comparatively low position, that is to say two transverse, flat faces 55, mutually coplanar, each of which cuts perpendicularly one, respective, of the axes 19 when the part 54 occupies its comparatively low position.

Naturally, these two faces 55 or the single face replacing them are offset upwards, like the whole of the part 54, when the latter occupies its comparatively high position.

 The evolution of the part 54 between its comparatively high position and its comparatively low position can be controlled manually from the command and control panel 4, by means of the command and control electronics 16, or automatically by this last, according to a cycle also involving the control of the bar feeders 8 and the pins 20, as can be seen with reference to FIGS. 8 to 10.

 When you are about to machine, by means of the turning lathe 1 according to the invention, two new bars 6, that is to say two bars 6 in which no part has yet been machined by means of this turn 1, the part 54 is placed in a comparatively low position as shown in FIG. 8, in the absence of the bars 6 or when the front ends 47 thereof are still spaced from the barrels 34 towards the rear then, by means of the bar feeders 8, the two bars 6 are advanced longitudinally, through the pins 20 then loosened, until the ends 47 of the two bars 6 abut forwards against the faces 55 of Exhibit 54, as shown in Figure 8.

 Then, as shown in FIG. 9, each of the pins 20 is tightened on the corresponding bar 6 in order to join them mutually, it being understood that the movable headstock 14 then occupies an extreme rear position.

 Then, as shown in FIG. 10, the part 54 is retracted upwards, which breaks the support of the ends 47 of the bars 6 on the faces 55 of the stop part 54, so that by advancing the movable headstock 14 towards the fan 11, a longitudinal penetration of each of the bars 6 is caused in the corresponding barrel 34, and this until the bars 6 emerge from the guide guns 34 in front of the fan 11, forming by relative to the reference face 48 an identical longitudinal projection since the longitudinal translation of the two bars 6 from their position resulting from their abutment towards the front against the part 54 has the same amplitude and thus preserves the mutual transverse alignment obtained by abutted against the part 54.

 The tightening of the pins 20 on the bars 6 and the translation of the tailstock 12 forwards after tightening of the pins 20 on the bars 6 are controlled from the command and control panel 4 by means of the electronics of command and control 16 or automatically by the latter.

 Identical machining can then be carried out simultaneously on the parts of the two bars 6 cantilevered towards the front relative to the fan 11, whether it is the machining of a first part on each bars 6, or whether it is a result of the machining of bars 6 on which parts have already been machined, detached at the end of machining by cutting off the corresponding bar 6.

 To carry out this machining, the fan 11 projects on its front face 48 two identical tool-holder turrets 56, each of which is capable of carrying at least one tool and of orienting the latter towards one, respectively, of the axes 19 for machining the corresponding bar respectively, it being understood that the two turrets 56 carry identical tools for practicing identical, simultaneous machining, on the two bars 6 and that certain tools can also consist of tools which must be placed according to the respectively corresponding axis 19, in particular for carrying out axial bores in the two bars 6.

 Each of the turrets 56 has a structure and a mode of connection with the fan II known in themselves in the case of towers with movable headstock and single spindle, it being understood that if two turrets are sometimes provided on such towers, these two turrets carry in principle different tools, intended to carry out different machining operations on the single bar then.

 To carry each of the turrets 56 and move these turrets 56 relative to the corresponding axis 19 respectively, away or in approach, in a manner controlled by the command and control electronics 16 and by the command and control panel 4 , each turret 56 is mounted on a respective carriage 57 itself mounted for translation in a transverse direction X relative to the fan 11 it will be noted that this transverse direction X is the same for the two carriages 57 in the example illustrated , and in practice parallel to the plane 53, that is to say horizontal, but that one could also mount each carriage 57 in translation relative to the fan 11 in its own transverse direction, that is to say -to say different from one carriage 57 to another, as soon as this assembly makes it possible to bring the two turrets 56 closer or further apart as required with respect to the corresponding axis 19 respectively.

 To guide each carriage 57, respectively, in translation in the direction X, the fan 11 carries integrally, on its rear face 50, slides 105 oriented in the direction X, these two pairs being mutually symmetrical by relative to the plane 18 and arranged respectively on either side of the guide guns 34 and the two slides 105 of each pair being mutually symmetrical with respect to the plane 53.

 Each of the pairs of slides 105 carries with the sliding in the direction X, without other possibility of relative displacement, the one, respective, of the carriages 57 that a respective electric motor 59 secured to the fan 11 and controlled on and off by the command and control electronics 16 and the command and control panel 4 makes it possible to move, by means of a ball screw 60 of direction X or a similar device, in translation in the direction d 'A distance or approximation with respect to the nearest axis 19, or to immobilize at a determined distance from this axis. The two motors 59 can be arranged in the extension of the ball screws 60 or other similar device as shown diagrammatically in FIG. 3 but, preferably, they are placed behind the rear face 50 of the fan II and connected to the corresponding ball screw 60 by a constant velocity transmission 61 as shown diagrammatically in FIG. 5.

 Optionally, the two motors 59 can be ordered as a para

 Each of the carriages 57 thus mounted, only one of which has been illustrated in FIG. 5 for reasons of clarity but which are identical and identically mounted, crosses the fan 11 longitudinally, right through, through a respective light 62, so to carry the respectively corresponding turret 56 projecting longitudinally forward with respect to the front face 48 of the fan 11.

 In a manner known in itself, each turret 56 is indexable with respect to the carriage 57 around a respective longitudinal axis 61 located in the example illustrated in the plane 53, without any other possibility of relative displacement, it being understood that the distances separating respectively each of the axes 61 of the nearest axis 19 are identical by virtue of the aforementioned command to move the carriages 57.

 The respective indexing of the two turrets 56 is caused by a respective motor 62 carried integrally by the corresponding carriage 57, the two indexing motors 62 being controlled in the same way as the motors 59, by the control and control 16 and the control and control panel 4, so that the respective indexing of the two turrets 56 are identical, that is to say that these two turrets 56 simultaneously present, at a given instant, identical tools towards the nearest axis 19, or along this axis, or else parallel to it in the absence of rotation of the bars, to practice identical machining. For this purpose also, the two turrets 56 carry the respective tools in the same order around the corresponding axis 61, preferably however with reference to opposite circumferential directions.

 The turrets 56 can also be of any known type, having any desired number of means for removably receiving tools, for example by fitting and elastic retaining, as shown diagrammatically at 63 in FIGS. 6 and 7; however, it is chosen to connect each tool such as a cutting or straightening tool 164 or a drilling tool 165 to the corresponding turret respectively by means 166, 167 allowing individual micrometric adjustment of each tool in the longitudinal direction and, as regards the cutting or dressing tools, in transverse position in order to allow individual compensation for possible differences in wear and tear between otherwise identical tools carried respectively by one and the other of the turrets 56 and thus ensuring identical simultaneous machining using these tools.

 In addition, when these differences in wear manifest themselves in the longitudinal direction, they can be corrected, depending on the tools used at a given instant, by acting on the relative longitudinal position of the two pins 20, according to an implementation variant of the invention which has been illustrated in FIG. 13, where the same numerical references are found as in FIGS. 2, 4, 5 in particular, to designate identical or similar components.

 In particular, we find in Figure 13 the longitudinal slides 13 of the main bench not shown, and the movable headstock 14 mounted for longitudinal sliding relative to this bench via the slides 13, in a manner controlled by a ball screw 21 longitudinal, itself driven via a constant velocity transmission 22 from a motor 15 secured to the main bench and for example arranged in this case at a level lower than that of the slides 13, inside of a light not shown corresponding to the longitudinal light 101 above.

 Upwards, the movable headstock 14 carries two pins 20 ', 20 "in every point identical to the pins 20 except that only one of them, namely the pin 20", is longitudinally fixed relative to mobile doll 14.

 While the axes 19 of the two spindles 20 "and 20" 'keep the positions described above, the spindle 20 "is adjustable longitudinally with respect to the movable headstock 14 and, for this purpose, is mounted for rotation around its axis 19, with no other possibility of relative movement, inside a carriage 102 mounted for longitudinal sliding relative to the movable headstock 14, by means of longitudinal slides 103 of the latter, without other possibility of movement relative.

 To cause controlled movements of longitudinal offset of the spindle 20 "relative to the spindle 20 ', in order to take account of differences in longitudinal dimensions observed on samples of machined parts, in relation to the machining operations carried out from a determined tool of the turrets 56, or to place the spindle 20 "in the same longitudinal position as the spindle 20 'in the absence of such an offset, the carriage 102 integrally carries an electric motor 105 for example of the stepper type. not, acting on the carriage 102 by means of a ball screw 112 of longitudinal axis 206 and of a constant velocity transmission 109 for example by pulleys and belt, or by the intermediary of any equivalent device; thus, an operator having observed a difference in longitudinal dimensions on samples of parts machined from the two bars 6 by means of identical tools carried respectively by one and the other of the turrets 56 can introduce via the table command and control 4 a corresponding correction data of the relative longitudinal position of the pins 20 'and 20 "so that, when the tools in question are used, in a manner controlled by the command and control electronics 16, the motor 105 is driven in one direction and over a number of steps such that the bars 6 offset each other, longitudinally, by a value suitable for compensating for the difference in wear between the two tools; naturally, a correction of the same type, respectively adapted value, can be provided automatically when each of the tools carried by the turrets 56 is used as soon as a check of the p Machined parts allowed to detect a shift in the longitudinal dimensions of the machining carried out using these tools.

 It will be noted that the longitudinal stroke accomplished by the carriage 102, relative to the movable headstock 14, with a view to such corrections has a limited maximum value, for example of the order of a few tenths of a millimeter or, at most, of the order of a few millimeters, so that one can keep to ensure the driving of the pins 20 'and 20 "in rotation about their respective axis 19 a constant velocity transmission with belts and pulleys or the like, connecting each of these pins 20 ', 20 "respectively to the electric motor 25 carried integrally by the movable headstock 14, for example above the pins 20' and 20" and behind them with reference to the direction 12.

In this case, the intermediate shaft 28 intended, preferably, to cause the rotation of the guide barrels 34 on themselves around the axes 19 by means of the shaft 37 and the constant velocity transmission 36, for example by belt and pulleys, is rotated about its axis 29, in synchronism with the pins 20 'and 20 ", by constant velocity connection with one of them, and for example with the pin 20' by the intermediate of a transmission 110 with belt and pulleys disposed in front of the spindle 20 'with reference to the direction 12; as has been described in particular with reference to FIGS. 2, 3 and 4, the intermediate shaft 28 is also connected by means of a constant velocity transmission 27, for example by belt and pulleys, to the encoder 26 carried integrally by the movable headstock 14, between the two pins 20 'and 20 ".

 Of course, one could also adopt in this case a positioning of the electric motors 25 and 15, and a mode of constant velocity connection of the latter with the respectively corresponding mobile components of the lathe, analogous to those which have been described with reference to FIGS. 2 to 5 , in particular, as could be adopted in the case of the lathe described with reference to FIGS. 2 to 4, a positioning and a constant velocity connection of the motors 15 and 25 similar to those which have just been described with reference to FIG. 13 .

 Preferably, each of the turrets 56 is chosen to be of a type suitable for mounting and driving rotary tools such as, for example, circular circular saws 58 visible in FIGS. 2 and 3, or other motorized tools such as cutters intended for example to machine flats on the bars 6 then stationary in rotation, and there is preferably provided on each assembly formed by a carriage 57 and a turret 56 common drive means for all the tools thus mobile carried by the turret 56 considered.

 Thus, in a manner known per se and as illustrated in FIG. 3, each of the carriages 57 can advantageously carry integrally a respective electric drive motor 64, having a respective output shaft 65 arranged along the 'respective axis 61 I and connected by a respective bevel gear 66, inside the turret 56 considered, to one or more return shafts 67 radial relative to the axis 61 considered; when it is a question of driving a transverse circular saw 58 via a respective radial shaft 67, a respective support 68 of this circular saw 58, acting as an intermediary for mounting the latter on the turret respective 56, contains a bevel gear 69 making it possible to drive the respective circular saw 58 to rotate about an unreferenced longitudinal axis, relative to its support 68 and to the respective turret 56; when it comes to driving a tool, such as a milling cutter, to rotate about a radial axis with respect to the axis 61 of the respective turret, in a manner not shown, the intermediate mounting support for the milling cutter on the turret does not contain an angle gear 69 and the kinematic connection of the milling machine with the gear shaft 67 can be made directly, coaxially, or indirectly with or without axis offset, via of a gear train. These arrangements are known to a person skilled in the art and do not require further description but, in accordance with the present invention, the two motors 64 are controlled on and off, by the command and control electronics 16 and the table. of command and control 4, so as to drive the shafts 65 to rotate in the same direction and at the same speed with respect to the assembly in question of a carriage 57 and a turret 56.

 Thus, the two turrets 56 are able to practice, in accordance with the present invention, identical simultaneous machining on the two bars 6, with or without rotation of the latter depending on the case.

 To increase the number of tools capable of working in particular simultaneously with those of the turrets 56 on the bars 6, depending on the case with or without rotation of the latter around the axis 19, the fan 11 carries projecting forward , on its front face 48, not only the turrets 56, but also a tool-carrying carriage 70 mounted movable in translation, on the face 48, in a direction Y perpendicular to the plane 53 as well as to the directions Z and X, c that is to say vertical.

 To this end, the face 48 of the fan It carries in a solid manner slides 111 oriented in the direction Y but otherwise identical to the slides 58, and for example located between the guide guns 34.

 The slides 111 thus defined carry the carriage 70 to slide in the direction Y without any other possibility of relative displacement, and translational movements of the carriage 70 up or down in the direction Y can be caused by an electric motor 78 controlled by the command and control electronics 16 and the command and control panel 4; this motor 78 acts on the tool carriage 70 by means of a ball screw 79, arranged in the direction Y, for example along the plane 18, or of another equivalent device, and it is carried so secured by the fan 1 1 either in direct extension of the ball screw 79 as shown in diagram 12, or opposite the rear face 50 of the fan II as shown in diagram FIG. 2, in which case the motor 78 is connected to the ball screw 79 by a constant velocity transmission 106.

 Above the plane 53, in the mutually symmetrical positions with respect to the plane 18, the carriage 70 carries in the example illustrated in FIGS. 2 and 12 two tool supports 71, integral with the tool carrier carriage 70 but adjustable in position relative to the latter, which tool supports 71 are suitable for receiving mutually identical tools 72 each of which is turned towards one, respectively, of the axes 19. The means for adjusting each support 71 relative to the carriage 70 can be chosen from any type known to a person skilled in the art, and allow the two tools 72 to be placed in strictly identical positions relative to the axis 19 respectively associated, it being understood that this position identity refers to the active part of the tool.

 It is easy to see that the motor 78, by lowering the tool-carrying carriage 70 and consequently bringing the tools 72 closer to the axis 19, makes it possible to practice using these tools, simultaneously, identical machining of the two bars 6; a movement of the tool-carrying carriage 70 upwards, under the action of the motor 78, enables the tools 72 to be released from the bars 6.

 Such an upward movement can be used to bring the bars 6 into the attack position, alternately with the tools 72, two other tools 73 carried, by means of a respective tool holder 75, by the carriage 70 below plane 53, in positions which are mutually symmetrical with respect to plane 18 and preferably with the possibility of adjusting wear compensation so as to ensure identical simultaneous machining of the two bars 6 by means of tools 73.

 In the example illustrated in FIGS. 2 and 12, the tools 72 are of the static type while the tools 73 are of the rotary type, and driven to rotate about a respective axis 74, vertical, by motor means, for example integrated to the respective tool holder 75 and controlled by the command and control electronics 16 and the command and control panel 4 so as to cause the two tools 73 to rotate with identical speeds around the respective axis 74 when the bars 6 are stopped; however, a person skilled in the art will readily understand that the nature of the tools 72 and 73 can be freely chosen, provided that the two tools arranged above the plane 53 are mutually identical and mutually symmetrical with respect to the plane 18, as are the two tools 73 arranged below the plane 53.

Naturally, the tool carriage 70 could also carry tools parallel to the axes 19 and intended to work along these axes 19 or parallel to them, in a manner easily understood by a
Man of the trade.

 FIG. 16 illustrates various types of tools capable of being carried simultaneously, or alternately, by the tool-carrying carriage 70, an embodiment of which offering numerous mounting possibilities for such tools is further illustrated in this FIG. 16, where we find the slides 111 guiding this carriage 70 to slide in the direction Y on the fan not shown, the ball screw 79, the constant velocity transmission 106 and the motor 78 causing controlled movements of the carriage 70 in this direction Y , relative to the fan, the two turrets 56 and one of the guide guns 34, of longitudinal axis 19 as well as the longitudinal direction 12.

In this variant, the carriage 70 has forward, with reference to the direction 12, a transverse, flat face 113 of generally rectangular shape, delimited by two short sides arranged in the direction
X and two long sides arranged in the direction Y, in a relationship of mutual symmetry with respect to the longitudinal plane, vertical 18 of symmetry, not visible in this figure 16.

 In this plane, the face 113 is hollowed out with a rectilinear groove 114 thus disposed in the direction Y, which groove 114 has a square or rectangular section, constant, when it is seen in section through any horizontal plane. In addition, near one and the other of its short sides, the face 113 is hollowed out of two rectilinear grooves 115 arranged in the direction X and having, in any cutting plane parallel to the plane 18, an identical section to that of the groove 114. Between the two grooves 115 are arranged in the face 113 several other grooves 116, here three in number, which grooves 116 are rectilinear and arranged in the direction X, and have in section by any parallel plane in plane 18 a section identical to that of the grooves 115 and 114.

 The grooves 114, 115, 116 allow the integral, adjustable and removable mounting, by means known to a person skilled in the art, of various types of tool holders and tools, some examples of which are illustrated in FIG. 16 , it being understood that these tools are arranged in pairs of identical tools, juxtaposed mutually in the direction X and mutually symmetrical with respect to the plane 18 not shown.

 Thus, each of the grooves 115, generally intended to remain permanently respectively above and below the axes 19 during the evolution of the carriage 70 in the direction Y, are more particularly suitable for receiving respective tool holders 117, mutually symmetrical with respect to the plane 18 not shown, static tools for example cutting, such as the tools 72 previously described, intended to work while being turned towards the axis 19 and mutually symmetrical with respect to the plane 18, or even a tool holder 118 carrying two rotary tools 73 mutually symmetrical with respect to the plane 18 and intended to work while being turned towards the axis 19, these rotary tools 73 being driven in rotation relative to the tool holder 118, around the respective axis 74, vertical, by common motor means 119 advantageously carried by the tool holder 118 and controlled by the command and control electronics 16 and the switchboard command and control 4 so as to drive the two tools 73 to rotate with identical speeds around the respective axis 74 when the bars not shown are at 1 stop.

 The grooves 116, intermediate between the grooves 115, are for their part more particularly intended to receive the tool-holders of tools intended to work longitudinally, along the axes 19 or parallel to these, statically with respect to the tool-holder corresponding or with rotation about a longitudinal axis with respect to this tool holder.

Thus, from top to bottom if we refer to FIG. 16 and by way of nonlimiting example, the carriage 70 carries by the three grooves 116
a pair of tool holders 120 mutually juxtaposed in the direction X and each of which carries in a solid but removable manner, and preferably adjustable longitudinally, a longitudinal drill 121 arranged in a vertical plane including one, respective, of the axes 19, the drills 121 thus being mutually symmetrical with respect to the plane 18 not referenced,
- A pair of tool holders 122 mutually juxtaposed in the direction X and each of which carries integrally, removably and preferably longitudinally adjustable, a respective tap 123 arranged in a vertical plane including a respective axis 19, the two taps 123 thus being mutually symmetrical with respect to the plane 18 not shown,
a pair of tool holders 124, mutually juxtaposed in the direction X, and each of which carries a respective longitudinal drill bit 125, arranged along a vertical plane including a respective axis 19, by means of means 126 allowing, in a manner controlled by the command and control electronics 16 and the command and control panel 4, to cause the two drills 125 to rotate about their respective longitudinal axis, not referenced, in a synchronized manner and to move them longitudinally in one direction or in the other with respect to the carriage 70 and to a respective bar during machining, not shown.

 The drills 121 and 125 as well as the taps 123 are directed towards the rear with reference to the direction 12.

 It is easy to see that, by a controlled movement of the carriage 70 in the direction Y, it is possible, alternatively, towards the bars 6 to be machined, not visible in FIG. 6, the drills 121, the taps 123, the drills 125 or, where appropriate , static cutting tools 72 or rotary tools 73, for example for transverse drilling, the bars in the latter case being stationary.

 However, these tools only represent nonlimiting examples of tools capable of being carried, by pair of identical tools mutually juxtaposed in the direction X and mutually symmetrical with respect to the plane 18, by the face 113 of the carriage 70 and, at By way of illustration, FIG. 16 shows two tool holders 126 intended to be thus mutually juxtaposed in the direction X by mounting in one of the grooves 116, replacing one of the pairs of tool holders 120 , 122, 124 mentioned above, these two tool holders 126 bearing in positions which may be mutually symmetrical relative to the plane 18 of the cutting tools 127 having a generally longitudinal shape, oriented towards the rear with reference to the direction 12, and having leading edges 118 intended to be turned towards one, respectively, of the axes 19.

 Through the grooves 116 on its faces 70, the carriage 70 can also temporarily support devices which do not constitute tools and, for example, a pair of supports 219 similar to carriers has been illustrated in FIG. 16. tools and, like the tool holders of the same pair, intended to be integrally mounted, adjustable and removable in one of the grooves 116, to present, along a respective axis 19, a respective coaxial sleeve 220 capable of serving as support and guide, in rotation about the respective axis 19, for a part being machined having a particularly large length, that is to say a particularly large longitudinal overhang, in the direction 12, relative to the respective barrel 34; for this purpose, each sleeve 220 can advantageously be treated internally so as to offer the least possible obstacle to relative rotation around the axis 19, and for example wear internally a coating with a low coefficient of friction, or even be provided internally rolling means similar to a barrel 34, however generally with freedom of rotation about the respective longitudinal axis relative to the respective support or tool holder 219.

 A person skilled in the art will easily understand that by the notion of mutual symmetry of tools 72, 73, 121, 123, 125, 127 with respect to plane 18, as moreover of symmetry of tools such as 58, 164, 165, turrets 56 with respect to this plane 18, we mean a mutual symmetry of the zones of these tools such as the leading edges 128 of the tools 127, capable of attacking the bars 6 during their rotation and / or their longitudinal displacement, or their stop .

 A person skilled in the art will also easily understand that, as soon as the bars 6 are stopped in their rotation about the respective axis 19, at least tools mounted rotatably around a longitudinal axis, such as the drills 125, can be used not only along the respective axis 19, but also parallel to this axis, just as one can then use rotary tools around transverse axes, such as tools 73.

 If the nature of the machining requires it, additional tools 88 can also be provided on a third turret 76 disposed in front of the front face 48 of the fan 11 and carried, with the possibility of indexing, without other possibility of relative displacement, around a longitudinal axis 77 coinciding with the intersection of the planes 18 and 53, that is to say located between the axes 19 and equidistant from each other, on a counter headstock 80 itself mounted in longitudinal translation on the auxiliary bench 10.

 For the purpose of guiding the tailstock 80 in longitudinal translation without any other possibility of relative movement, this auxiliary bench 10 has two longitudinal slides 81 which are mutually symmetrical with respect to the plane 18 and identical to the slides 13 and, to cause in a controlled manner by the command and control electronics 16 and the command and control panel 4 for the translational movements of the tailstock 80 along the slides 81, the engine bench 10 carries securely, for example between the slides 81 an electric motor 87 having an output shaft 82, forming a longitudinal projection forward with respect to the auxiliary bench 10 and driven in rotation about a longitudinal axis 83 when the motor is supplied with electricity, so as to drive, by means of a constant velocity transmission 84, a simultaneous rotation, around a longitudinal axis 85 for example placed in the plane 18 , a ball screw 86 or other equivalent device, cooperating with the tailstock 80 to translate such a rotation by a translation in the longitudinal direction Z, that is to say by bringing the turret closer or further away 76 relative to fan 11.

 As shown schematically in Figure 3, the motor 87 could also be placed in the direct extension, towards the front, of the ball screw 86 to drive the latter directly, to rotation about the axis 85, and cause the aforementioned translational movements of the tailstock 80 and the turret 76.

 It is thus possible, in a manner controlled by the command and control electronics 16 and the command and control panel 4, to move the bars 88 closer or further apart during the machining of the tools 88 carried by the turret 76, in longitudinal projection rearwardly relative to the latter, in the form of pairs of identical tools 88 which are mutually symmetrical with respect to the axis 77 and spaced from the latter by a distance corresponding to the distance separating from this axis 77 each of the axes 19.

 It is easy to see that by rotating the turret 76 around the axis 77 relative to the tailstock 80, it is possible to bring the tools 88 of Itune or the other pair along the axes 19 or parallel to them at will, in respective respective positions with respect to them, as soon as the rotation of the bars 6 around their axis 17 is stopped, in order to practice machining, for example drilling, boring or coaxial tapping in particular at the ends 47 of the bars 6 when, in addition, a translation of the tailstock 80 is rearwardly brought to bring the tools 88 into contact with the bars 6.

 To ensure such indexing of the turret 76, the tailstock 80 integrally carries an indexing motor 89 controlled by the command and control electronics 16 and by the command and control panel 4 in the same way as the motor 87.

 Similarly, to cause possible rotation of the tools 88 about their respective longitudinal axis 90 relative to the turret 76, the tailstock 80 includes a drive motor 91 also controlled by the command and control electronics 16 and by the command and control panel 4 and kinematically linked to the tools 88, in a manner easily determinable by a person skilled in the art.

 Note that in its illustrated embodiment, the turning lathe according to the invention 1 may comprise on each turret 56 six tools capable of working alternately on the respective bar 6, the tool carriage 70 carries in relation to each bar 6 two tools capable of working alternately, however simultaneously with one or the other of the tools carried by the turrets 56, and the turret 76 itself comprises, in relation to each bar 6, three tools capable of working alternately, however simultaneously with a tool from the tool carriage 70 and a tool from the turret 56 corresponding to the same bar 6. If we also take into account that it is possible to provide turrets 56 comprising a greater number of tools , for example eight tools, as well as a turret 76 comprising a greater number of tools, it is easily conceivable that a turning lathe according to the invention 1 offers wide possibilities s simultaneous machining or two successive bars 6, and therefore allow access to particularly high production rates.

 In addition, the turret 76 may advantageously comprise, as illustrated, two return pins 129 turned longitudinally rearward, with reference to the direction 12, like the tools 88 and mounted for rotation relative to the turret 76 around d 'respective longitudinal axes 130, under the action of the motor 91; the axes 130 are mutually symmetrical with respect to the axis 77 of the turret 76 and mutually spaced by a distance corresponding to the mutual spacing of the axes 19 so that, by indexing the turret 76 around the axis 77 relative to the tailstock 80, in a manner controlled by the command and control electronics 16 and by the command and control panel 4, it is possible to place the return pins 129 coaxially with the bars 6 and the parts machined to starting from the latter, then printing against the tailstock 80 a translation first towards the rear, up to a longitudinal distance from the fan 11 just sufficient to allow the passage of tools for cutting the bars, carried by the turrets 56, then forwards, with reference to the direction 12, so as to take these parts coaxially when they are separated from the bars 6 by cutting, for example by means of saws 58, accompanying any ro tation of the bars 6 around their axis 19 during this cutting-off by a rotation, of the same speed and in the same direction of the return pins 129 around their axis 130 relative to the turret 76.

 Then, after a new indexing of the turret 76 relative to the tailstock 80, so as to offset the axes 130 relative to the axes 19, and using on the one hand longitudinal translation movements of the tailstock 80 and, if necessary, a joint rotation of the recovery pins 129 around the respective axis 130 and of the parts thus carried by the recovery pins 129, and on the other hand of the tools carried by the carriage 70 in an illustrated mounting variant in FIG. 17, carry out additional machining of these parts while other parts are being machined, in particular by means of the tools carried by the turrets 56, on an extreme overhang of the bars 6 towards the front, with reference to direction 12, in relation to fan 11.

 Reference will be made in this regard to FIG. 17, where the carriage 70 described with reference to FIG. 16 is identically found in particular and the tailstock 80 carrying the turret 76 itself carrying the return pins 129 , likely to be rotated about their respective axis 130, relative to the turret 76, by the motor 91, illustrated in a position different from that which is illustrated in Figure 2, or to be stopped in any angular position determined around this respective axis 130 relative to the turret 76. There is also the motor 89 which makes it possible to orient the turret 76 around its axis 77 relative to the tailstock 80 in particular so as to make each coincide axes 130 with a respective axis 19, not illustrated in FIG. 17, for carrying out the recovery of already machined parts, at the time of their separation from the bars 6 by sectioning, and an angular offset position rement around the axis 77 relative to this initial recovery position, namely preferably a position illustrated in Figure 17 in which the two axes 130 are mutually superimposed vertically, in the plane 18 not shown in this figure.

 To cooperate with the already partially machined parts carried by the pins 129 and occupying this other position or machining position, the carriage 70 carries in a solid but removable and adjustable manner, by its face 113 and more particularly by the groove 114 thereof. ci, by means known to a person skilled in the art, longitudinal tools, turned forward with reference to direction 12 and corresponding to each other by pairs of mutually identical tools, arranged in the plane 18 not shown in the FIG. 17, mutually spaced vertically by a distance corresponding to the mutual spacing of the axes 130 of the return pins 129, that is to say to the mutual spacing of the axes 19, and mutually symmetrical with respect to a longitudinal axis respective 174, 175, 176 also located in plane 18.

 These tools may consist of static tools, as illustrated, or alternatively of tools driven in rotation about a respective longitudinal axis by motor means preferably integrated into the respective corresponding tool holder, serving as an assembly intermediary. of the tool on the carriage 70, these motor means being controlled by the command and control electronics 16 and the command and control panel 4.

 Naturally, the tools of the different pairs follow one another in the same order, vertically, respectively in an upper half and in a lower half of the carriage 70 so that by vertical translation then stop of the latter under the action of the motor 78, and while the turret 76 occupies its position for machining the parts temporarily secured to the pins 129, it is possible, by making the axes 174, 175, 176 coincide successively with the axis 77, present successively along the respective axes 130 of the recovery pins 129, while the turret 76 occupies its machining position, the two tools of each pair; identical tools are thus presented simultaneously opposite the two recovery pins 129 so that, by a longitudinal translational movement of the tailstock 80 successively rearward, up to a longitudinal distance from the fan 11 just sufficient to allow the passage of cutting tools, carried by the turrets 76, then forwards with reference to the direction 12, it is possible to machine the parts carried by these two pins 129 identically and then to release the tools.

 Advantageously, one of the tools of each pair is permanently located below the plane 55 of the axes 19, not illustrated in FIG. 17, while the other is permanently located above this plane 55, in order to allow to give the dimension of the carriage 70 and its amplitude of displacement along the Y axis of values as low as possible.

By way of nonlimiting examples of tools thus capable of being carried by the face 113 of the carriage 70 for machining parts carried by the return pins 129, FIG. 17 has been illustrated.
- a pair of longitudinal drills 131,
a pair of longitudinal taps 132, each of which is arranged immediately above a respective drill 131,
- Two other longitudinal drills 133 having a diameter different from that of the drills 131 and each of which is disposed immediately above a respective tap 132.

 It is easily understood that such cooperation between return pins 129 carried by the turret 76 and tools such as 131, 132, 133 carried by the carriage 70 makes it possible to considerably increase the production rates of the lathe, by offering a possibility to carry out certain machining operations on parts after the latter have been detached from the bars and while others of these parts are being machined directly on these bars, in particular by means of the tools carried by the turrets 56.

 Less advantageously, in the absence of a carriage 70, it is also possible to cooperate with the return pins 129 of the turret 76, suitably oriented around the axis 77 relative to the tailstock 80, with suitably oriented tools, carried by the turrets 56, it being understood that it is more difficult then to use the latter to simultaneously practice machining on the bars 6; this solution has, however, in the same way as the solution described with reference to FIG. 17, an advantage in that it makes it possible to machine parts by an inaccessible zone when these are still attached to the corresponding bar 6, know by their end from the cutting of the latter or rear end with reference to the direction 12, for example for drilling or boring and possibly tapping these parts by this end.

 This possibility has been illustrated schematically in FIG. 14, however in the case of the replacement of the turret 76, on the tailstock 80, by a transverse carriage 134 mounted for translation in the direction Y with respect to the tailstock 80, meanwhile mounted as previously indicated.

 More specifically, the carriage 134 is connected to the tailstock 80 by vertical slides 135 which guide it in vertical translation, that is to say in the direction Y, relative to the tailstock 80.

 To ensure the immobilization of the carriage 134 against such a translation, in privileged relative positions, or to ensure the passage from one to the other of these privileged positions, the carriage 134 cooperates forward, with reference to direction 12, with a ball screw 136 mounted for rotation about a vertical axis 137 relative to the tailstock 80, without any other possibility of relative displacement, this ball screw 136 being driven to rotate around its axis 137 by an electric motor 138 secured to the tailstock 80; the ball screw 136 is connected to this electric motor 138 by means of a constant velocity transmission 139 and the electric motor 138 is controlled by the command and control electronics 16 and by the command and control panel 4 in machining function to be carried out using the carriage 134.

 Backwards with reference to the direction 12, the latter carries several pairs, mutually superimposed in the direction Y, of mutually identical tools 88, mutually juxtaposed in the direction X and more precisely mutually symmetrical with respect to the plane 18 not shown, thus that a pair of return pins 129 with axes 130, also mutually identical, mutually juxtaposed in the direction X and more precisely mutually symmetrical with respect to the plane 18, this pair of pins 129 being juxtaposed in the direction Y with the pairs of tools 88.

 The tools 88 like the axes 130 of the pins 129 are placed along vertical planes including the axes 19 so that, by a translational movement of the carriage 134 in the direction Y relative to the tailstock 80, it can be presented according to this axis 19, longitudinally opposite the bars 6 not illustrated in FIG. 14, respectively one and the other of the tools 88 of the same pair or the recovery pins 129, respectively for machining parts still integral with the bars 6 or take these parts back when they are separated from the bars by sectioning, by means of a translation of the tailstock 80 backwards then forwards with reference to the direction 12, under the same conditions as when the tools 88 and the spindles recovery 129 are carried by the turret 76.

 In this case also, the tools 88 may be static, that is to say remain integral with the carriage 134 when they are in service, while advantageously being adjustable and removable with respect to the carriage 134 by means of non-means represented, known to a person skilled in the art; they can also be mounted for rotation about a respective longitudinal axis 90, relative to the carriage 134, as is the case of the return pins 129 which can rotate around their axis 130 relative to the carriage 134; naturally, in this case also, the tools 88 can be adjusted in their position relative to the carriage 134, and are removable with respect to the latter, by use of intermediate mounting means known to a person skilled in the art.

 To ensure the possible drive of the tools 88 to rotate about a respective longitudinal axis 90, as well as the drive of the return pins 129 to rotate around their axis 130, one can provide respective motor means, naturally controlled by the command and control electronics 16 and the command and control panel 4, but preferably a common motor 140 is thus provided, thus controlled, carried in solidarity by the carriage 134, towards the front with reference to the sense 12; this motor 140 is connected, by constant velocity transmissions 141, for example to belts and pulleys, to respective longitudinal shafts 142 passing through the carriage 134 with respect to which they are mounted for rotation about respective longitudinal axes, namely the axes of respective rotation 90 of the tools 88 or the axes 130 of the pins 129, to ensure a transmission of movement towards the tools 88 and the pins 129.

Providing in this case, on the carriage 134, recovery pins 129 allows
- By placing the carriage 134 in a recovery position in which the axes 130 coincide with the axes 19 and successively causing a translation of the tailstock 80 backwards then forwards with reference to the direction 12, d ' take up the machined parts from the bars 6, not illustrated in Figure 14, during their cutting; for this purpose, the tailstock 80 approaches the fan 11, during its rearward movement with reference to the direction 12, up to a longitudinal distance of this range as small as possible but nevertheless sufficient to allow the passage of the cutting tools, carried by the turrets 56, between the recovery pins 129 and the fan 11,
- Then, by bringing by means of the motor 138 the carriage 134 to another position or machining position, offset for example upwards relative to the position for taking up the machined parts and then successively causing a movement of the counter headstock 80 backwards then forwards with reference to direction 12, placing the parts provisionally attached to pins 129 in the longitudinal alignment of tools 143 that the turrets 56 present towards the front, with reference to direction 12 , in positions that are mutually symmetrical with respect to the plane 18 not visible in FIG. 14, to machine the parts by means of these tools 143 which can be static or driven to rotate about a respective longitudinal axis, and to release the parts with respect to these tools after machining in accordance with the present invention, the tools 143 thus used for machining parts carried respectively by the return pins 129, in mut positions only symmetrical with respect to plane 18, are mutually identical.

 Naturally, a carriage of the type described under the reference 134, carrying tools 88, can also be used without recovery pins 129 and without cooperation of such recovery pins 129 with tools such as 143 presented forward, with reference to direction 12, by turrets 56; similarly, the turret 76 previously described may not have recovery pins 129, and the carriage 70, if any, not carry tools such as 131, 132, 133 capable of machining parts carried by such recovery pins, if it is not necessary to machine the parts by their end from the separation from the bars, by sectioning.

 In such a case, also, it is possible to replace on the tailstock 80 the turret 76 indexable by rotation about a longitudinal axis and the carriage 134 movable in vertical translation, to carry tools and present them successively in a position of machining the bars, a carriage 144 of the type illustrated in FIG. 15.

 This carriage 144 is mounted on the tailstock 80, meanwhile mounted as described above, by means of slides 145 oriented in the direction X so as to guide the carriage 144 in translation along this direction relative to tailstock 80.

 This translation, and the immobilization of the carriage 144 in determined positions, in the direction X, relative to the tailstock 80 can be caused, in a controlled manner by the command and control electronics 16 and by the control panel and control 4, by an electric motor 146 carried integrally by the tailstock 80 and connected by a constant velocity transmission 147 to a ball screw 148 mounted on the tailstock 80 along an axis 149 oriented in the direction X, and cooperating with the carriage 144.

 According to the plane 55, not illustrated in FIG. 15, of the axes 19, the carriage 144 carries integrally but preferably adjustable and removable several pairs of tool holders 150 mutually juxtaposed in the direction X; the tool holders 150 of the same pair carry identical tools 151, arranged along the plane 55, and are mutually spaced along the direction X by a distance corresponding to the mutual spacing of the axes 19 so that, by positioning suitably the carriage 144 relative to the tailstock 80, in the direction X, it is possible to present simultaneously in the longitudinal alignment of the two bars 6, not visible in FIG. 15, mutually identical tools 151.

 Naturally, the tools 151 can be static tools or tools driven in rotation relative to the corresponding tool holder 150, around a respective longitudinal axis arranged along the plane 55, just as a pair of these tools 151 could be replaced by a pair of longitudinal recovery pins, similar to recovery pins 129, easily conceivable by a skilled person.

 The longitudinal movements of the tools 151, leading to the engagement of the latter with the bars and then to their release with respect to the latter, can result exclusively from translational movements of the tailstock 80 towards the rear then towards the front, with reference to direction 12, in a manner controlled by the command and control electronics 16 and the command and control panel 4, by means of a motor and of a similar ball screw to those which have been described respectively under the references 87 and 86.

 However, taking into account that the size of the carriage 144 in the direction X would risk in this case causing interference of the tools 151 with the turrets 56, it is preferable to dissociate the respective longitudinal translational movements of the tools 151 and the counter - 80 doll.

More precisely, the latter is in this case movable in translation along the slides 81 only between two limit positions, for example under the action of a jack 152 controlled by the command and control electronics 16 and the command and control panel 4, namely
a rest position which constitutes the front limit position, with reference to the direction 12, and in which the tools 151 are not called upon to work,
- a rear limit position, with reference to the direction 12, in which the tools 151 can be used to machine the bars 6, not visible in FIG. 15, but nevertheless remain offset towards the front, with reference to the direction 12, with respect to to the latter, so that none of them comes into contact with the turrets 56 or hinders the movements of the latter.

 In order to be able to be brought into a position in which they interfere with the bars and machine the latter, the tools 151 are mounted inside the respective tool holders 150 with the possibility of longitudinal sliding between a front limit position, in which they do not thus not interfere with the bars even when the tailstock 80 occupies its rear limit position, and to which they are brought back elastically, by means the production of which falls within the domain of the normal aptitudes of a person skilled in the art, and a rear position adjustable under the control of the command and control electronics 16 and of the command and control panel 4, as a function of a machining to be carried out, and in which they interfere with the bars.

 To this end, from each tool holder 150 protrudes, forwardly with reference to direction 12, a respective pusher 153 secured to the respective tool 151 with respect to a longitudinal translation; the various pushers 153 are thus mutually juxtaposed in the direction X, and along the plane 55 not visible in FIG. 15.

 To cooperate with the two pushers 153 corresponding to tools 151 of the same pair, placed at a given time along the axes 19 so as to make these tools interfere with the bars and machine the latter, the tailstock 80 carries by l 'Intermediate longitudinal slides 154 an auxiliary carriage 155 placed in front of the carriage 144 with reference to the direction 12 and carrying along each of the axes 19, rearward with reference to the direction 12, a longitudinal thrust rod 156; the push rods 156 are thus placed directly forward, longitudinally and with reference to direction 12, pushers 153 corresponding to the same pair of tools 151 placed along the axes 19 at a given instant.

 The auxiliary carriage 155 cooperates with a longitudinal ball screw 157 mounted for rotation about a longitudinal axis 158 relative to the tailstock 80 and capable of being rotated in one direction or the other around this axis 58 by an electric motor 159 controlled by the command and control electronics 16 and the command and control panel 4; this motor 159 is also carried by the tailstock 80 and the ball screw 157 is connected to it by means of a constant velocity transmission 160, for example with belts and pulleys.

 It is easy to see that by means of the motor 159, suitably controlled, the carriage 155 can be placed in any desired longitudinal position relative to the tailstock 80 itself occupying its rear limit position with reference to the direction 12, as a function of 'a machining to be carried out by means of the tools 151 then placed along the axes 19, to also place these tools 151 in a longitudinal position determined as a function of this machining to be carried out, with respect to the bars 6 not illustrated in FIG. 15; when the machining to be carried out by means of these determined tools 151 is completed, a controlled movement of the carriage 155 forwards with reference to the direction 12 allows the pushers 153 to be returned, integral in this respect with the corresponding tools 151, in their front limit position with reference to direction 12 in order to be able to move the carriage 144 in the direction X relative to the tailstock 80 and possibly place other tools 151 in the longitudinal extension of the bars 6 to start the same process again with these new tools .

 When all of the desired machining operations have been carried out, the two parts machined simultaneously are detached from the bars 6 by cutting off the latter, by means of tools carried by the turrets 56, as indicated above.

 It will be noted that the identity of the machining of the two bars 6, or of spare parts thereof after the start of machining, may require that the tools used simultaneously, carried by the carriage 70, the turret 76 or the carriages 134, 144, are not rigorously symmetrical to each other with respect to plane 18 or to accommodate them, in a manner easily conceivable by a person skilled in the art; the notion of mutual symmetry of these tools, set out in the foregoing, should be considered to include mutual asymmetries, generally slight at least as regards at least the overall position of the tools, as long as they correspond to a identity of machining of bars or parts made from them.

 The parts thus produced by means of the different versions of the lathe according to the invention which have just been described, depending on the case either after they have been detached one by one from the bars 6 by sectioning, or after which have been released by the recovery pins 129, the turret 76 then preferably occupying an orientation such that the axes 130 of the recovery pins 129 coincide with the axes 19, can fall freely, in bulk, in receptacles such as baskets arranged under the fan 11 .

 However, it is preferable on the one hand not to mix the parts coming respectively from one and the other of the bars 6, to allow by periodic control to detect the wear of one or the other of the working tools respectively on one or the other of the bars 6 or on the parts taken up by the take-up pins 129 and on the other hand to avoid a free fall of the parts, risking damaging the latter as well as the tools such as the tools 73 possibly planed under the bars 6 during machining.

 To this end, in accordance with a preferred embodiment, the turning lathe 1 illustrated comprises means for taking up the workpieces machined from the bars 6, and these take-up means are individualized, that is to say specific to the workpieces machined from one or other of the bars 6, respectively.

 A first example of embodiment of such individual recovery means has been illustrated in FIG. 2.

 Only the individual recovery means 92 associated with one of the bars 6 have been detailed in FIG. 2, it being understood that the individual recovery means 92 associated with the other of these bars 6 are identical to them.

 These individual recovery means 92 comprise a longitudinal shaft 93 projecting forwardly relative to the front face 48 of the fan 11 and mounted relative to the latter on the one hand to the longitudinal translation and on the other hand upon rotation about a longitudinal axis 94, beyond the corresponding turret 56 in the direction of a distance from the plane 18; the movements of rotation of the shaft 93 around the axis 94 and of longitudinal translation of the shaft 93, relative to the fan 11, can be caused by any suitable motor means, not detailed, controlled by the electronics command and control 16 and by the command and control panel 4.

* Cantilevered in front of the front face 48 of the fan 11, the shaft 93 integrally carries a first section 95 of a telescopic transverse arm 96, moreover having a second section 97 capable of sliding in one direction or the other with respect to the section 95, under the action of motor means controlled by the command and control electronics 16 and by the command and control panel 4.

 At a free end opposite its connection with the section 95, the section 97 carries a clamp 98 of generally tubular, longitudinal shape, capable of being opened or closed by motor means not shown, controlled from the command and control electronics 16 and of the command and control panel 4 these opening and closing movements of the part 98 correspond to the delimitation, by the latter, of an inner diameter respectively greater than the diameter of a bar 6 to be machined, with the possibility of transverse escape from this bar or more precisely from a machined part having the diameter thereof, or substantially equal to that of the bar to be machined or from a part machined from that -this.

 In addition, below the shaft 93 is provided a longitudinal conveyor 99 exiting the frame 2 of the machine in front of the latter and suitable for conveying towards the front, that is to say towards the outside of the machine. frame 2 of the machine, the parts produced successively from the bar 6 considered; two of these conveyors 99 are thus provided on the basis of one for the parts originating respectively from one or the other of the bars 6, in positions that are mutually symmetrical with respect to the plane 18.

The recovery means 92 are co-cutting, in practice consisting of a circular saw 58 making it possible to make clearer cuts, not requiring subsequent resumption of machining.
- the clamp 98 is then closed if it was not closed previously and the cutting of the corresponding bar 6 is carried out
- After this cutting, the arm 93 advances, taking the machined part, thus separated from the rest of the bar 6, by joint advance of the part 98
- Then, the arm 93 pivots so as to turn the part 98 downwards and to place it immediately above the conveyor 99, this movement being accompanied by a mutual translation of the two sections 95 and 97 of the arm 96 taking into account that the distance separating from the axis 94 the conveyor 99 is generally less than the distance separating from this axis 94 the axis 19 of the corresponding bar 6
- the clamp 98 is then open, as shown diagrammatically in FIG. 2, which drops the machined part 100 on the conveyor 99, which routes this part 100 forwards and outwards from the frame 2 of the machine, for recovery, for example, in tanks specific to one and the other of the conveyors 99
- the clamp 98 is then optionally closed and brought back, by pivoting of the arm 93 around the axis 94 and telescopic movement of the two sections 95 and 97 of the arm 96, in its initial position, coaxial with the bar 6 during machining .

 If the parts machined from the two bars 6 are supported by recovery pins 129 after their separation from the rest of the corresponding bar 6 by cutting, one can use the same recovery means 92 and deduce their operating sequence from the sequence which has just been described, by replacing the longitudinal movements of the clamps 98 towards the rear, that is to say towards the bars 6, and towards the front, that is to say away from with respect to these bars 6, by longitudinal movements of the clamps 98 respectively towards the front, that is to say towards the recovery pins 129 assumed to be placed coaxially with the axes 19, in particular for carrying out the handling of the parts machined, with release of the latter vis-à-vis the recovery pins 129, and rearward, that is to say in the direction of a distance from the recovery pins 129 to release the parts machined.

 A second embodiment of the means for the individual take-up of the parts machined from the two bars 6 has been illustrated in FIG. 18 where these means have been designated by the general reference 161 and where the range 11 is also found, the axes 19, the guide guns 34, the turrets 56, and the carriage 70, as well as the frame 2 of the lathe.

 In the case of this embodiment, the fan 1 1 has above each of the guide barrels 34, in positions mutually symmetrical with respect to the plane 18 not shown in this figure and according to each of the vertical planes including the a, respective, of the axes 19, two guide spans 162, with longitudinal sliding without any other possibility of relative displacement, for a longitudinal rod, respective rectilinear 163 which, thus, crosses the fan 11 right through.

 Behind the fan 11, with reference to the direction 12, the two rods 163 are mutually connected in an integral manner by a transverse yoke 264 which is also connected, towards the quarry with reference to the direction 12, to a longitudinal, straight rod 265 arranged along the plane 18 and constituting the rod of a longitudinal cylinder 266 carried integrally by the frame 2 of the machine and allowing, under the control of the command and control electronics 16 and of the command and control panel 4, to move longitudinally, in unison, the two rods 163 to place them in determined longitudinal positions relative to the frame 2 of the lathe and relative to the components thereof.

 In front of the fan it with reference to the direction 12, and at the same transverse level, the two rods 163 respectively carry, in an integral manner, a vertical arm 267 which is connected to the respective rod 163 by an upper end zone and moreover has a lower end zone at the level of one, respectively, of the axes 19 coaxially to which the arm 267 considered carries integrally a respective longitudinal sleeve 168.

 The two sleeves 168 are thus permanently placed along the respective axis 19 in the illustrated version of the recovery means 161, which is adapted to the case of a lathe having no tailstock 80. When such a tailstock must be provided, there should be provision for transverse retraction means controlled sleeves 168, easily conceivable by a skilled person.

 The two sleeves 168 are open towards the front and towards the rear, with reference to the direction 12, and are delimited internally by a respective internal peripheral face 169 of cylindrical revolution around the respective axis 19 with a diameter greater than a few tenths millimeters to the maximum diameter of a part machined from bars 6, with reference to the respective axis 19; the two sleeves 168 are mutually identical, and arranged at a longitudinal distance from the fan 11 which varies according to the longitudinal position of the rods 163 but is permanently identical for the two sleeves 168.

 In front of the two sleeves 168, with reference to the direction 12, and along each of the axes 19, the frame 2 carries integrally, in the example illustrated, a respective ejection pusher 70 having the shape of a longitudinal rod, rectilinear, for example cylindrical of revolution about the respective axis 19 with a diameter less than that of the inner peripheral face 168 of a sleeve 169 so that, by displacement as a result of a joint movement of the two sleeves 168 forward, they can be engaged on the respective rods 170; the latter have longitudinal dimensions substantially identical to those of the sleeves 168 so that they can thus cross the latter longitudinally, right through.

 Naturally, the fixity of the ejection pushers or rods 170 with respect to the frame 2 of the lathe corresponds to the case of a lathe having no movable tailstock 80; when such a tailstock is provided, the rods 170 can be mounted on this tailstock so as to be able to be presented along the axis 19 alternately with the tools or rework pins carried by this tailstock; thus, if one refers to the various embodiments of a tailstock 80 which have been described, the push rods 170 can be arranged, in a manner easily conceivable by a person skilled in the art, either on the turret 76, in diametrically opposite positions relative to the axis 77 and to a mutual spacing identical to that of the axes 19, that is to say on the carriage 134, in a relationship of mutual symmetry with respect to the plane 18 with a mutual spacing identical to that of the axes 19, or on tool holders 150 of the carriage 144, mutually spaced along the axis X by a distance equal to the mutual spacing of the axes 19 and with longitudinal actuation by means of a respective pusher 153.

 Furthermore, however the rods 170 are connected to the frame 2, namely directly as illustrated in FIG. 18 or by means of a tailstock 80, they can be mounted longitudinally telescopic to penetrate into the sleeves 168 not only due to a longitudinal displacement of the latter relative to the frame 2 of the machine, but by proper longitudinal displacement of the rods 170 relative to this frame 2.

 The operation of the means 161 for taking up machined parts can easily be deduced from that of the means 92.

If one refers first of all to the illustrated mounting mode of the rods 170 on the frame 2 of the machine and, that is to say in the absence of tailstock 80, these means 161 are controlled by the command and control electronics 16 and the command and control panel 4 according to the following sequence
- Initially, it will be considered that the sleeves 168 occupy an extreme forward position, with reference to the direction 12, in which they are fully engaged on the rods 170; they are then shifted forward, with reference to the direction 12, relative to the fan 1 1 by a sufficient longitudinal distance so that they completely release the parts being machined and do not constitute an obstacle to operation of the tools carried by the turrets 36 or the carriage 70
- After machining two identical parts but before separating them from the rest of the bars 6, not visible in Figure 18, by cutting, each sleeve 168 is brought into an extreme rear position, with reference to the axis 12, which constitutes a support position in which it surrounds the corresponding corresponding machined part but is nevertheless spaced longitudinally from the fan II and from the corresponding guide barrel 34 respectively, with reference to direction 12, by a distance longitudinal just sufficient to allow the passage of a cutting tool carried by the turret 36 respectively associated;
- We then practice the cutting of each bar to detach the respective machined part, which remains retained by the sleeve 168 respectively corresponding;
- Then, the two sleeves 168 are moved longitudinally forward, in the direction 12, by action by means of the jack 166, until they are brought back to the abovementioned initial position; when they come close to this position, which constitutes a position for evacuating the machined parts, the rods 170 penetrate into the sleeves 168, from the front with reference to the direction 12, and drive out the machined parts, which fall by gravity, simultaneously, out of the two sleeves 168 from the rear of the latter, with reference to direction 12.

 The operating sequence of the recovery means 161 in the presence of a tailstock 80, in particular when the latter comprises recovery pins 120, can easily be deduced from the above, it being understood that the sleeves 168 then remain in a retracted position transversely relative to the axes 19, so as not to impede the operation of the tailstock 80, when they are not in service.

 To collect separately the machined parts thus obtained from the two sleeves 168, the frame 2 of the lathe presents immediately behind the position that these sleeves 168 occupy when they are engaged on the rods 170, and at a level lower than that of the sleeves 168 , the respective inlets 171 of two chutes 172 which descend from these respective inlets 171 to a respective tray 173 for recovering the parts, open a respective longitudinal conveyor similar to the longitudinal conveyors 99 described with reference to FIG. 2, in a manner not shown in Figure 18 but easily conceivable by a skilled person.

 A person skilled in the art will also easily understand that the sleeves similar to the sleeves 168 could be substituted for the pliers 98 of the individual recovery means 92 described with reference to FIG. 2, as soon as they are provided in a suitable position, above the conveyors 99, ejection means similar to the ejection pushers 170. Such an embodiment would be compatible with the presence of a tailstock 80 and its operation could be easily deduced from the above.

 Naturally, these embodiments of the means 92 and 161 for taking up machined parts 100 constitute only nonlimiting examples, as are the embodiments, previously described, of turrets 56, of the tool carriage 70, of the turret 76 and tool carriages 134, 144. There could be many other alternative embodiments of these recovery means 92, 161 and these different tool means 56, 70, 76, 134, 144 both as regards the general structure of these tool-carrying means as regards their drive mode and the possible drive mode of the tools in the case of rotary tools, or of the take-up spindles when they exist; in particular, it could be more convenient to drive rotating or otherwise mobile tools, or take-up spindles, carried by the tool-carrying carriage 70, the turret 76, the carriages 134 and 144, by hoses kinematic connection with a motor suitably carried by a freely chosen component of turn 1, or even by connection by means of hoses to a source of pressurized fluid, according to the sources of energy available in particular.

 The production of such variants falls within the normal abilities of a person skilled in the art, as does the production of electronic command and control means 16 and of the command and control panel 4, which will therefore not be detailed and may moreover vary to a large extent.

 In general, the lathe which has just been described could undergo numerous modifications without departing from the scope of the present invention.

Claims (23)

 1. Turning lathe of the type comprising  - a bench (9, 10) having a determined longitudinal direction (2) and integrally comprising a transverse fan (11),  - a headstock (14) mounted movable in longitudinal translation relative to the bench (9), on a first side of the fan (11) with reference to the longitudinal direction (2),  a first spindle (20) mounted movable for rotation about a first longitudinal axis (19) relative to the headstock (14) and capable of receiving coaxially a first bar (6) to be machined, provisionally secured,  a first barrel (34) for guiding the first bar (6) in longitudinal translation and in rotation about the first axis (19) relative to the fan (11), coaxial with the first spindle (20) and in the longitudinal extension thereof,  a first tool holder means (56) mounted movable in translation in a first transverse direction (X) relative to the fan (11), on a second side of the latter with reference to the longitudinal direction, and capable of carrying at least one tool (58, 164, 165) and of presenting it in the longitudinal extension of the first spindle (20),  - motor means (15, 25, 59) controlled as a function of a machining to be carried out to cause controlled movements of longitudinal translation of the headstock (14) relative to the bench, of rotation of the first spindle (20) around the first axis (19) relative to the headstock (14), and translation of the first tool-carrying means (56) in the first transverse direction (X) relative to the fan (11),  - means (4, 16) for controlling and controlling the controlled motor means (15, 25, 59),  characterized in that it comprises  - a second spindle (20) mounted movable for rotation about a second longitudinal axis (19) relative to the headstock (14) and capable of receiving coaxially a second work bar (6), temporarily attached,  a second barrel (34) for guiding the second bar (6) in longitudinal translation and in rotation about the second axis (19) relative to the fan (11), coaxial with the second spindle (20) and in the longitudinal extension thereof,  - a second tool holder means (56) mounted movable in translation in a second transverse direction (X) relative to the fan (11), of said second side thereof, and capable of carrying at least one tool ( 58, 164, 165) identical to said tool (58, 164, 165) of the first tool-carrying means (56) and to present it in the longitudinal extension of the second spindle (20),  - means (16, 23) of kinematic coupling on the one hand between the first and second pins (20), to the longitudinal translation joint with the headstock (14) relative to the bench (9) and to the rotation around the first and second axes (19) relative to the headstock, and on the other hand between the first and second tool-carrying means (56), in translation along the first and second transverse directions (X), so as to present simultaneously identical tools (58, 164, 165) in the longitudinal extension of the first and second spindles (20) and simultaneously machining identical parts (100) from the first and second bars (6).  2. Tower according to claim 1, characterized in that the first and second guide barrels (34) are mounted for rotation in the fan (11) respectively around the first axis (19) and around the second axis (13) , and in that means (36) are provided for kinematic coupling of the first and second guide guns (34) with the first and second pins (20) for rotation about the first and second axes (19).  3. Lathe according to either of claims 1 and 2, characterized in that the first and second tool-carrying means (56) comprise first and second tool-carrying turrets (56) capable of carrying several respective tools simultaneously (58, 164, 165) identical for the first and second turrets (56), in that the first and second turrets (56) are indexable around a respective longitudinal axis (61) to present, respectively in the longitudinal extension of the first spindle (20) and in the longitudinal extension of the second spindle (20), an identical determined tool, and in that the controlled motor means (15, 25, 59) include means (64) for causing identical controlled indexing of the first and second turrets (56) around their longitudinal axis (61), so as to present simultaneously identical tools in the longitudinal extension of the first spindle (20) and in the extension t longitudinal of the second spindle (20).  4. Tower according to any one of claims 1 to 3, characterized in that the first and second transverse directions (X) are combined.  5. Tower according to any one of claims 1 to 4, characterized in that the first and second tool-carrying means (56) are disposed respectively on either side of an assembly formed by the first and second barrels of guide (34).  6. Tower according to any one of claims 1 to 5, characterized in that it comprises a third tool holder means (76, 134, 144) mounted movable in longitudinal translation relative to the bench (10), the second side of the fan (11), and capable of carrying at least one pair of identical tools (88, 151) or of recovery pins (129), the tools (28, 151) or recovery pins (129) of said pair being disposed respectively in the longitudinal extension of the first spindle (20) and in the longitudinal extension of the second spindle (20), and in that the controlled drive means (15, 25, 59) comprise means (87, 152) to cause controlled movements of longitudinal translation of the third tool holder means (76, 134, 144) relative to the bench (10).  7. Tower according to claim 6, characterized in that the controlled motor means (15, 25, 59) comprise controlled means (91, 140) for synchronized drive of the spindles for resumption of rotation on themselves relative to the third tool holder means (76, 134, 144).  8. Lathe according to any one of claims 6 and 7, characterized in that the third tool holder means (76, 134, 144) comprises a third tool holder turret (76) indexable around a longitudinal axis (77 ) coplanar with the first and second axes (19) and equidistant from the latter, in that the third tool turret (76) is capable of carrying several pairs of mutually identical tools (88), respectively said pair of spindles recovery (129), arranged mutually symmetrically with respect to the longitudinal axis (77) of the third turret (76), and in that the controlled drive means (15, 29, 59) include means (89) for causing a controlled indexing of the third turret (76) around its longitudinal axis (77) so as to present simultaneously identical tools (88) or the recovery pins (129) in the longitudinal extension of the first and second pins (20).  9. Tower according to any one of claims 6 and 7, characterized in that the third tool-carrying means (76, 134, 144) comprises a tool-carrying carriage (134) mounted movable in translation in a third transverse direction (Y) relative to the bench (10) and capable of carrying several pairs of mutually identical tools (88), respectively said pair of return pins (129), mutually juxtaposed in a fourth transverse direction (X) parallel to a plane (55) defined by the first and second axes (19), said pairs of tools (88), respectively said pair of take-up spindle (129), being mutually juxtaposed in the third transverse direction (Y) and the third transverse direction (Y) being secant from said plane (55), and in that the controlled motor means (15, 25, 59) comprise means (87) for causing controlled movements of translation of the tool carriage (134) according to the third e transverse direction (Y) relative to the bench (10) so as to present simultaneously identical tools (88) or the recovery pins (129) in the longitudinal extension of the first and second pins (20).  10. Tower according to claim 9, characterized in that the third transverse direction (Y) is perpendicular to said plane (55).  11. Tower according to any one of claims 6 and 7, characterized in that the third tool-carrying means (76, 134, 144) comprises a tool-carrying carriage (144) mounted movable in translation in a fourth transverse direction (X) relative to the bench (10), and capable of carrying several pairs of mutually identical tools (151), respectively said pair of return pins, mutually juxtaposed in the fourth transverse direction (X), the fourth transverse direction ( X) being parallel to a plane (55) defined by the first and second axes (19), and in that the controlled motor means (15, 25, 59) include means (146) for causing controlled movements of translation of the tool carriage (144) in the fourth transverse direction (X) with respect to the bench (10) so as to present simultaneously identical tools (151) or the recovery pins in the longitudinal extension of the first and two ith pins (20).  12. Tower according to any one of claims 1 to 11, characterized in that it comprises a fourth tool holder means (70) mounted movable in translation in a third transverse direction (Y) relative to the fan ( 11), on the second side thereof, and capable of carrying at least one pair of mutually identical tools (72, 73, 121, 123, 125, 127) or of means (220) for supporting the bars (120) , mutually juxtaposed in a fourth transverse direction (X) parallel to a plane (55) defined by the first and second axes (20), the third transverse direction (Y) being intersecting from said plane (55), and in that the means controlled motors (15, 25, 59) comprise means (78) for causing controlled movements of translation of the fourth tool holder means (70) in the third transverse direction (Y) relative to the fan (11), so as to present tools simultaneously (72, 73, 121, 123, 125, 127) id entiques or the means (220) for supporting the bars (120) in the longitudinal extension of the first and second pins (20).  13. Tower according to claim 12, characterized in that the third transverse direction (Y) is perpendicular to said plane (53).  14. Lathe according to any one of claims 12 and 13, characterized in that the fourth tool holder means (70) is capable of carrying a plurality of pairs of tools (72, 73, 121, 123, 125, 127 ) mutually identical, mutually juxtaposed in the fourth transverse direction (X), said pairs of tools being mutually juxtaposed in the third transverse direction (Y).  15. Lathe according to any one of claims 12 to 14 in combination with claim 8, characterized in that the fourth tool holder means (70) is capable of carrying at least one pair of tools (131, 132, 133 ) mutually identical turned towards the third turret (76), arranged mutually symmetrically with respect to a respective longitudinal axis (174, 175, 176) of the fourth tool holder means, coinciding with the longitudinal axis (77) of the third turret ( 76) in a privileged position of the fourth tool-carrying means (70), in that the means (29) for causing a controlled indexing of the third turret (76) are suitable for simultaneously placing the recovery pins (129), controlled manner, in a recovery position in which they are arranged respectively along the first axis (19) and along the second axis (19) and in at least one machining position in which they are placed in the extensions lo respective lengths of the tools (131, 132, 133) of said pair, while the fourth tool holder means (70) occupies said privileged position.  16. Lathe according to any one of claims 1 to 15, characterized in that each tool-carrying means (56, 70, 76, 134, 144) comprises means (166, 167) for individual adjustment of the tool or tools (164, 165) respectively.  17. Tower according to any one of claims 1 to 16, characterized in that it comprises means (102, 103, 105, 109, 112) for relative longitudinal adjustment of the first and second spindles (20 ', 20 ") .  18. Tower according to claim 17, characterized in that the first spindle (20 ') is longitudinally fixed relative to the movable headstock (14) and in that the adjustment means (102, 103, 105, 109, 112) longitudinal relative of the first and second spindles (20 ', 20 ") comprise means (102, 103, 105, 109, 111) for longitudinal adjustment of the second spindle (20') relative to the movable headstock (14).  19. Tower according to any one of claims 1 to 18, characterized in that it comprises means (49) for mutual transverse alignment of the first and second bars (6) prior to their machining.  20. Tower according to claim 19, characterized in that the transverse alignment means (49) comprise at least one abutment part (54) having a planar abutment face (55) and mounted movable relative to the fan ( 11), on the first side thereof, between a position in which the stop piece (54) is interposed between the first and second pins (20), on the one hand, and the first and second guide guns ( 34), on the other hand, and in which the abutment face (55) cuts the first and second axes (19) perpendicularly while being turned towards the first and second pins (20), and a position in which the abutment piece (54) releases the respective longitudinal alignments of the first pin (20) and the first guide gun (34), on the one hand, and the second pin (20) and the second guide gun (34), from somewhere else.  21. Tower according to any one of claims 1 to 20, characterized in that it comprises means (92, 161) for taking up parts (100) machined from the first and second bars (6).  22. Tower according to claim 21, characterized in that the means (92) for taking up the parts (100) machined from the first and second bars (6) comprise first and second clamps (98) mounted movable relative to the 'fan (11), on the second side thereof, between a position for taking over a respective part (100), in which the first and second clamps (98) are arranged respectively along the first axis (19) and along the second axis (19), and a discharge position, and in that the controlled motor means (15, 25, 59) include means for causing a controlled evolution of the first and second clamps (98) between their positions handling and evacuation as well as opening and closing movements of the grippers (98).  23. Tower according to claim 21, characterized in that the means (161) for taking up the parts (100) machined from the first and second bars (6) comprise first and second sleeves (168) mounted movable relative to the 'fan (1), on the second side thereof, between a position for taking over a respective part (100), in which the first and second sleeves (168) are arranged respectively along the first axis (19) and along the second axis (19), and a discharge position, and first and second ejection pushers (170) able to penetrate longitudinally into the first and second sleeves (168), respectively, in the discharge position to drive out a respective machined part (100) longitudinally, and in that the controlled drive means (15, 25, 59) comprise means (266) for causing a controlled change in the first and second sleeves (168) between their positions of taken in cha rge and evacuation as well as relative longitudinal movements of the first and second sleeves (168), on the one hand, and ejection pushers (170), on the other hand, at least when the first and second sleeves arrive or are in the evacuation position.