FR2707538A1 - Multi-tool spindle and multi-bar machine tool using it - Google Patents

Abstract

The tool holder spindle (10) on its outer surface has a circular bearing ring (16) followed by a cylindrical part (18) extended by a screw thread (19). Tools (20, 24, 25) having decreasing radii of action and internal diameters corresponding with the external diameter of the cylindrical part (18) are slipped over the cylindrical part and are clamped between the bearing ring (16) and a clamping flange (28) integral with a bolt (27) engaged in the screw thread (19).

Description

MULTI-TOOL SPINDLE AND MACHINE TOOL
OF MULTI-BAR IMPLEMENTATION
The present invention relates to a spindle driven in rotation and capable of carrying a plurality of tools. The invention also relates to a machine tool using the aforementioned spindle to completely machine, for example by drilling, milling and / or sawing, parts in the end of a bar. In particular, thanks to the aforementioned spindle, this machine tool can have several identical stations working simultaneously on bars arranged in parallel, each station performing the same sequence of several machining operations.

 Forests are known which have a tapered rear part making it possible to drill a hole and then immediately chamfer the edge. Document EP 0 352 224 describes a multi-directional monobloc cutting tool comprising several cutting edges: on the external and internal periphery of the front face, as well as on the periphery of the side wall. However, these monoblock tools can obviously only be used for machining operations planned during their design.

Known cutting tools are also known. For example, documents EP 0 391 695 and
FR 2 427 160 describe tapered cutters brought directly to a forest to deburr and chamfer the orifice of the drilled hole. But if the resistance encountered turns out to be too great, we end up damaging the lateral cutting lines, even breaking the forest, rendering it unusable later. Document FR 2 415 509 discloses a spindle carrying in its internal channel a forest clamped by a screw and on its periphery a hole saw screwed on a thread, this arrangement only making it possible to pierce a large diameter orifice by frontal advance.

 Document US 4,580,934 describes a spindle whose end has a coaxial thread and two radial grooves. This spindle is intended for a circular planer whose rear pins engage in the grooves, this planer being followed by a guide disc to center the tool in a hole already made in a piece of wood and which is desired. enlarge. A simple bolt engaged in the thread holds the two tools against the end of the spindle. Document DT 19 40 059 describes a similar tool in which the plane is replaced by a knife capable of attacking the metal. A rear ring mounted over the spindle on a thread confirms the orthogonal orientation of the knife. The retaining bolt has a thread oriented in the opposite direction to the direction of rotation of the spindle to prevent its loosening during work. The advantage of these removable cutting tools is that you can select the diameter of the knives and the front guide cylinder depending on the circumstances.

 However, again, these tools with only frontal action are applicable only for a single function, in this case widening orifices already drilled or machined in a perpendicular surface. The use of a bolt to assemble the tool causes the tip of the tool to be closed.

 The object of the present invention is a spindle capable of accommodating a wider range of tools, in particular a forest combined with milling cutters with lateral action, or even a circular saw capable of reaching the rear of a workpiece.

 This object is achieved by the fact that the support spindle of several tools has on its external surface a circular support ring followed by a cylindrical part extended by a thread, tools having decreasing radii of action, and internal diameters in correspondence with the external diameter of the cylindrical part being threaded thereon, and clamped between the support ring and a clamping flange secured to a bolt engaged in the thread.

 According to a preferred embodiment, the spindle is completed by an internal coaxial conduit with a conical mouth to receive a mandrel for holding a frontal forest.

 It is thus easy to assemble on the same spindle, from front to rear, a drilling forest, one or more milling cutters with lateral action to make grooves or the outline of a part, and finally a circular saw for cut off the finished part. The fact that the range of action of the tools is decreasing makes it possible to use them successively without the preceding tool interfering.

 Preferably, the circular support crown is machined with the spindle to provide, by construction, an intangible support exactly perpendicular to the axis of the spindle.

 If desired, the cylindrical part can have several stages of different diameters to receive tools having corresponding internal diameters.

 If desired, insert a spacing washer between two tools to enlarge the field of action of the smallest.

 Advantageously, the mandrel of the forest is pulled back simply by means of a conical screw orthogonally passing through the spindle at the rear of the support crown and penetrating into an orifice of this mandrel.

 Such a multi-tool spindle is advantageously used in a machine tool for machining complex parts in the end of a bar of material, such as, for example, links in a jewelry chain from steel or gold profiles.

 Indeed, if we consider a machine having to carry out a plurality of machining operations in the end of a bar by frontal and lateral attacks, like the machines described in documents WO 91 14534 or WO 89 11951, the adaptation of a single multi-tool spindle according to the invention in a single head capable of moving in the three axes of Cartesian coordinates makes it possible to overcome, in many cases, both individual lateral tool heads with radial displacement, and of the turret located opposite the bar and carrying a plurality of pins each holding a single tool. Even for milling machines with only lateral action, such as the machine described in document EP 0 385 315, the spindle according to the invention saves at least one of the side heads: either vertically plunging or horizontal diving.

 Alternatively, the spindle support head can be fixed and the bar support fully mobile, or a sharing of movements can be established between the two. This then results in a significant simplification of the machine inducing on the one hand reduced machine construction costs, and on the other hand shortened setting times between two series.

 In the field of micro-mechanics, it can be very advantageous to be able to work simultaneously on a plurality of bars arranged in parallel to best reduce the dead times of each tool, as well as the times of installation of the bars.

 As such, a machine is known comprising a vertical circular fixed support carrying on its periphery a plurality of regularly spaced stations, each carrying out only one operation controlled by a set of cams, installed at the rear of the support. The machine comprises opposite a circular structure coaxial with the support carrying on its periphery several parallel horizontal bars also regularly spaced. Once the machining cycles of all stations have been completed, the structure rotates to bring each bar end to the next station. When launching a new production, it is then necessary to adjust the precision of movement of a bar from one station to another, then to adjust the precision of the action of each tool. These adjustments prove to be long and tedious in practice. In addition, given the importance of the displacements, there is a risk of loss of precision during production.

 Another object of the invention is therefore a machine tool using the above-mentioned multi-tool spindles simultaneously on a plurality of bars arranged in parallel, so as to significantly increase productivity while maintaining rigorous machining precision.

These goals are achieved by a machine tool using multi-tool spindles according to the invention for the simultaneous machining of several parallel bars because it comprises
- A table carrying a series of blocks in which are arranged jaws for clamping the bar end piece, table further carrying a structure keeping the bars parallel to each other, and including a device for advancing the bars after each machining cycle ,
a support for an at least identical series of multi-tool spindles respectively located opposite a bar, these spindles being driven simultaneously at the same speed of rotation,
means of displacement of the table and / or of the support controlled by control means generating displacements of vertical, lateral and plunge machining, or combined displacements, displacements having the same repercussions for each multi-tool spindle facing a bar end,
means for adjusting the advance of each bar before closing the clamping jaws at the start of each machining cycle,
- a pair of bar / spindle being considered as a reference, separate means for adjusting the vertical initial position of the bar and the initial lateral position of the spindle at each other pair, or vice versa the means for adjusting the position vertical initial acting on the spindle.

 According to a preferred embodiment, the means for adjusting the advance of each bar comprise a series of stops situated in another part of the support accessible by the bars carried by the table, stops arranged in an identical manner as the pins, and whose the depth of each is individually adjustable by means of a micro-mechanical screw. Then, at the beginning of each cycle, the table simply brings the bars in front of their stops while remaining at a predetermined distance from the support, then the clamping jaws open to allow the bar advance device to push them. here against these stops, the jaws closing immediately after.

 In a preferred embodiment, each adjustable spindle is supported by a bearing block engaged in a horizontal (or vertical) slide; and the means for adjusting the initial position of the spindle comprise a screw parallel to the direction of adjustment, held movable in rotation in the support and engaged in a tapping of the bearing block in order to allow the movement of the latter in its slide. Similarly, a jaw gripping a bar is movable perpendicular to the slide of the spindle, the adjustment means comprising a screw held movable in rotation in the block and engaged in a tapping of the jaw.

 Preferably, the pins, and therefore also the bars, are aligned horizontally or vertically so that their support bearing blocks can be mounted in one and the same slide for adjusting their initial position. Furthermore, the horizontal alignment of the bars facilitates the installation of movable clamps under the clamping jaws, clamps coming to grip a finished part before it is separated from the bar, then bringing this part to a rework station or in a recycling bin.

 Preferably, the pins are driven by the same belt, or chain, driven by a usually electric motor. We can also consider a gear train, although this design is heavier.

 A first series of multi-tool spindles being aligned horizontally, we can then consider a second identical series of multi-tool spindles aligned vertically above the first, this second series of spindles being oriented downwards. direction of bar ends. These secondary multi-tool spindles can prove to be useful in the case of particularly complex parts requiring transverse drilling and / or cutting off using an eccentric grain.

 Advantageously, the supply of cooling oil can be carried out by a simplified pipeline based on a buffer tank located at the barycenter of all the pins.

The invention will be better understood from the study of an embodiment taken by way of nonlimiting example and described in the following figures
FIG. 1 is a perspective view of a multi-tool spindle according to the invention and its associated tools,
FIG. 2 is a side view of a machine tool using a plurality of multi-tool spindles according to FIG. 1,
FIG. 3 is a front view of the frame of the machine tool of FIG. 2 seen in direction III, and
- Figure 4 is a front view of the movable table of the machine of Figure 2 seen in direction IV.

 Referring to Figure 1, a tool spindle 10 comprises a body 14 extended rearwardly by a shank 12 capable of being subsequently engaged in the pliers of a rotary mandrel of a machine tool. More particularly, the front part of the spindle 10 consists of a support ring 16 followed by a cylindrical part 18 which is extended by a thread 19, these three zones being preferably machined in the mass. The spindle 10 further comprises an internal channel, the conical inlet 11 of which can be observed, the bottom of which is intersected by a threaded orifice 15.

 On the cylindrical part 18 of the spindle 10 can be threaded a plurality of circular tools, in particular with lateral action such as a saw 20, or a contour milling cutter 24 or a tooth milling cutter 25. Once these tools are installed, engages the bolt 27 on the thread 19 to tighten these tools between the flange 28 secured to the bolt 27 and the support ring 16.

 In the case of bar turning of small parts, the drive of the tools by the friction forces present between the support ring 16 and the flange 28 of the spindle proves to be sufficient, especially as the direction of the thread 19 is reversed relative to the direction of rotation of the spindle causing the torque of the workpiece to react on the tool drives the bolt 27 in an additional tightening direction. If necessary, the contact surfaces of the support crown, tools and the flange are engraved with a structure or covered with a material increasing the coefficient of friction. Obviously, if particularly large machining forces are required, it is always possible to envisage making a longitudinal groove on the cylindrical part 18 in order to insert a key therein which then engages in a radial notch formed in each of the tools 20 , 24.25.

 As illustrated in FIG. 1, it is important that the diameters of the tools decrease from the crown 16 towards the flange 28 so that a rear tool does not interfere during the machining carried out by a previous tool. If desired, a spacing washer 22 can be inserted between two tools, as illustrated here, between the cutter 24 and the saw 20 to widen the field of action of the lower tool, in this case the cutter contours.

As can easily be understood, it is also important that the diameter of the cylindrical part 18 corresponds exactly to the internal diameter of the tools 20, 24.

If necessary, the cylindrical part 18 can have one or more stages of different diameters to correspond to the internal diameter of the tools available on the market.

 In the internal conduit li of the spindle 10 can be engaged a mandrel 30 containing a forest 33, the nape of the clamps coming to bear against the conical part of the inlet of the channel 11, the rear end having an orifice 31 coming in correspondence with the threaded hole 15 of the spindle body 14. Thus, the tightening of the conical screw 13 entering the orifice 31 forces a recoil movement of the mandrel 30 whose clamps close on the forest 33 by feedback from the surface conical.

 A tool-holder spindle according to the invention therefore makes it possible to permanently mount several tools on the same axis, which avoids having to search for them successively on an adjacent magazine barrel. One can thus constitute, according to the specific characteristics of a part, a special tool capable, in stride, of drilling one or more holes, of bypassing different faces and, finally, of cutting the finished part. This special tool is then disassembled for subsequent reconstruction according to the criteria of a new series.

 In FIGS. 2, 3 and 4 is illustrated a machine tool advantageously using a plurality of multi-tool spindles according to FIG. 1 for simultaneously machining the same part in the end of several parallel bars 5. This machine tool is composed, as visible on the right of FIG. 2 and in FIG. 3, of a generally fixed support frame 45 carrying three horizontal parallel pins 10; and, as visible on the left-hand side of FIG. 2 as well as in FIG. 4, of a movable table 35 consolidated by an underlying square 38 and carrying, in correspondence, three blocks 37 in which the bar ends are held 5.

For a better understanding of the rest of the presentation, three axes of Cartesian coordinates of space are arbitrarily defined: a movement of lateral displacement X in a horizontal plane of the table 35 provided by displacement means 47 of the frame; a vertical movement Y of the table 35 provided by means 48 for moving the frame; and a displacement Z also in a horizontal plane but orthogonal to the displacement X provided here by the upper half of the frame 45 displaced by means 49. Advantageously, these displacement means 47,48,49 are controlled by a known device of programmable digital commands . However, it is obvious that the invention is in no way limited to the machine tool as illustrated, but extends to any machine tool capable of generating machining movements in three dimensions.
X, Y, Z cited between a part and a multi-tool spindle, either the table ensuring all movements in front of a fully fixed support frame, or the support frame ensuring all movements in front of a stationary table, or another sharing of movements between the table and the support frame.

 The support frame 45 of the machine according to the invention carries a plurality of bearing blocks 62, each bearing now movable in rotation, a mandrel capable of receiving and tightening the spindle shank 12 of a multi-tool spindle 10.

For example, the pliers of each mandrel can be tightened by means of a clamping ring 32.

 More particularly, and as visible in FIG. 3, the support frame 45 carries, horizontally from right to left, three mandrels furnished with identical active parallel pins and, on the far left, an additional mandrel capable of '' welcome another pin for a complementary operation. Among the three active spindles, the first right spindle is considered as a reference spindle and its position in the frame 46 is fixed once and for all. Conversely, the blocks carrying the two pins in the middle are engaged in a lateral slide 60 (Figure 2) so that their horizontal center line with the reference pin can be adjusted as necessary over a stroke of 10 millimeters . For this, each adjustable block 62 has a tapped hole 66 in which is engaged a screw 64 held movable in rotation in the frame 45, this screw being able to be turned from the outside by action on a button 65.

 With reference to FIGS. 2 and 3, the four spindle-holder mandrels are respectively extended at the rear by a pulley 72, these pulleys being driven simultaneously by the same belt 73 itself driven by a pilot pulley 71 connected to the end of the output shaft of a motor 70, this belt being, if desired, tensioned by a pulley 74.

 It may prove useful to provide, in this same support frame 45, a second identical series of mandrel / spindle 10 'vertical oriented downwardly located respectively in the vertical plane passing through their corresponding horizontal pins. This second series of mandrel / spindle is driven by the same horizontal belt passing through pulleys 72 'and a master pulley 71'. This master pulley can either be driven by a second independent motor or, as illustrated without any limitation being shown in FIG. 2, by a bevel gear driven by the main motor 70. This second series finds its advantage for particularly parts complexes requiring drilling and / or milling in both a horizontal and vertical plane.

 Advantageously, the cooling oil necessary for the machining operations is supplied by a network of tubes 82 based on a central buffer tank 80 located between the two series of spindles.

 Furthermore, the support frame 45 has, under the series of horizontal pins 10, three stops 50 having a center distance substantially identical to that of the three active pins, and whose more or less advanced position can be adjusted using of a device based on a micromechanical screw whose adjustment buttons 52 are accessible, in this example, from the front.

 With reference to FIGS. 2 and 4, the table 35 rigidly carries three blocks 37 in correspondence with the three active pins of the support frame, blocks in which jaws 39 for clamping the end of the bar 5 are held, the profile of these jaws being adapted to each bar profile to always be self-centering. For example, the opening and closing of these jaws can be remotely controlled pneumatically, the supply being effected by conduits 40 carried by a support 41.

The jaw on the left in FIG. 4, therefore in correspondence with the so-called reference pin located on the right of FIG. 3, is positioned intangibly in its block. Conversely, the other two central and right jaws 39 are adjustable in height in their blocks 37, that is to say in a direction orthogonal to the direction of lateral adjustment of the pins. This adjustment can be made, for example, over a stroke of 5 millimeters by means of a screw 55 engaged in a threaded orifice 56 of the jaws. The important thing is that the adjustment of a spindle is done in a direction perpendicular to the adjustment of the jaw, we could, of course, also have considered a vertical adjustment
Y for the pins in correspondence with a horizontal adjustment X for the jaws, although this construction would have been slightly heavier.

 As can be seen in FIGS. 2 and 4, a front group 95 of grippers 90 for gripping the parts being cut off is mounted movable in the vertical direction Y1 on the table 35. This group is guided by studs 98 sliding along columns 96. Each column is held at the bottom in the table 35 and at the top by column posts 99. The assembly 95 is lifted by a jack 97. Inside this assembly, means of displacement make it possible to open and close the clamps in the direction X1. The clamps are themselves chosen, like the clamping jaws, according to the profile of the bars to be self-centering. At the level of the clamps in the low position, compressed air conduits 92 are provided for ejecting a finished part from the open clamp.

 The bars 5 are contained inside tubes 43 kept parallel on a structure 36 connected to the table 35 by a pivot system 34. The structure 36 is in the form of a quadrilateral slightly deformable by rotation around the device 34 in order to allow the bars to be oriented, not only orthogonally to the support frame 45, but, if desired, obliquely within an angle of plus or minus 10 degrees.

 Each tube 43 contains a piston 44 located behind the bar allowing, once the jaw 39 is opened and the rear space of the tube pressurized by opening solenoid valves 42, to advance the bar at the rate of each cycle of production of parts.

 The implementation of the machine tool according to the invention is carried out schematically in the following manner.

 The machining cycle is initially programmed on the basis of displacement between the first reference jaw relative to the spindle in correspondence also of reference.

Then, the tubes 44 being strictly parallel, the stops 50 in the middle and on the left are adjusted to obtain a bar feed strictly identical to the feed of the first reference bar. A first adjustment is then made of the lateral center distance of the pins 10 in the middle and on the left as a function of the effective center distance of the jaws 39. A series of test machining operations is carried out and, depending on the results , again correct the spindle centers then, if necessary, also correct the height of the adjustable jaws in the middle and left. Once the rigorous machining identity of the parts has been acquired, these adjustments are definitively blocked, for example, by additional locking screws acting on the buttons 65 of the frame or on the screws 55 of the blocks 37. The rigidity of the positioning of the bars compared to the pins being assured, we can start production.

 For all practical purposes, a certain number of controls are provided, such as complete advancement of a bar or effective cutting-off of a finished part which are monitored by the digital control device and immediately stop the machine in the event of an incident.

 As can be seen from reading this presentation, the multi-bar machine using spindles according to the invention multi-tool is particularly advantageous in that it only includes small machining movements carried out so particularly precise, fast, and simultaneously on several bars in parallel. Production efficiency is thus increased by eliminating downtime and inaccuracies during large displacements previously required when moving the bar from one spindle to another or when moving a barrel multi-spindle successively bringing each tool in front of a single bar.

 Many improvements can be made to this multi-tool spindle and to the machine tool used in the context of this invention.

Claims (5)

1. Tool-holder spindle (10) characterized in that it has on its external surface a circular support ring (16) followed by a cylindrical part (18) extended by a thread (19), tools (20 , 24,25) having decreasing radii of action and internal diameters corresponding to the external diameter of the cylindrical part (18) being threaded thereon, and clamped between the support crown (16) and a flange tightening (28) integral with a bolt (27) engaged in the thread (19). 2. Spindle according to claim 1, characterized in that it is completed by an internal coaxial conduit (11) with a conical mouth to receive a mandrel (30) for maintaining a front forest (33). 3. Spindle according to claim 1, characterized in that the circular support ring (16) is machined with the spindle (10). 4. Spindle according to claim 1, characterized in that the cylindrical part (18) has several stages of different diameters for receiving tools having corresponding internal diameters. 5. Spindle according to claim 2, characterized in that the mandrel (30) of the forest (33) is pulled back by means of a conical screw (13) passing orthogonally through the spindle (10) at the rear of the crown support (16) and entering an orifice (31) of this mandrel.