FR2984787A1 - Tool changer for tool magazine assigned to machining head, has translation unit movable to adjustment position of adjusting unit, where adjusting unit is movable to variable position of tool holder by movement of tool magazine about axis - Google Patents

Abstract

The changer (6) has a tool holding unit i.e. grip (9), for holding of a tool (8), and an opening unit i.e. strut jack, for opening of the tool holding unit. A translation unit i.e. trolley, of the tool holding unit is movable between an inoperative position and a storage position in a tool magazine. The translation unit is movable to an adjustment position of an adjusting unit that is provided in the tool magazine. The adjusting unit is movable to a variable position of a tool holder i.e. ring (13), by movement of the tool magazine about an axis. An independent claim is also included for a method for installation and/or automatic withdrawal of a tool.

Description

The invention relates to the field of CNC machine tools, in particular that of machining centers. The machining centers are generally equipped with tool magazines on which the various tools are arranged. The 5 tool changes equipping the machining head (s) are programmed according to the numerical definition of the part. The machining center is equipped to perform such a tool change fully automatically. The tool whose operation is completed is stored in the magazine, and the tool 10 necessary for the next operation is taken from the same magazine to another location, this fully automatically. When the tools are worn out, they must be removed from the store, taken to a sharpening shop, sharpened, and returned to the tool shop of the machining center. The magazine removal operation requires that the machining center be shut down for safety reasons, and then the tool magazine is rotated until the tool to be removed is positioned in front of an opening made in the magazine. at the tool magazine, through which the operator can remove the tool. In general, it sets up another tool prepared in advance, to allow the machining center to continue its operations during the sharpening time of the removed tool. As soon as the new tool is put back in place, the tool magazine can return to its working position, and the machining center can be restarted. The downtime of the machining center is very expensive. Indeed the passage of a workpiece on the machining center is often on the critical path of the manufacturing time of the workpiece. Each second of stopping of the machine thus represents an additional time of manufacture. Moreover, the machining centers are expensive machines, and amortized by their operating time, often in operation day and night. Whenever the machining center has to stop, this represents a lost time, during which the machine produces nothing, and is therefore not amortized.

There is therefore a need to automate this tool change. The present invention more particularly relates to an automatic tool replacement device in a machining center tool magazine, more particularly to a crown-shaped magazine whose tools are arranged along the circumference. Such a crown-shaped magazine is movable about its axis A (see Fig. 1), this mobility enabling it to have, in front of the machining head, the tool selected by the machining center program, generally in the low position of the store in the shape of a crown. To then allow the machining head to deposit a tool in the store and to take another, the store is also rotatable about a substantially horizontal axis B located upward of the store, thus conferring a movement of the selected tool to the machining head to allow the machining head to grasp it. The magazine then makes a rotational movement about the B axis in the opposite direction to deviate from the machining head, and allow it to perform all the upward and downward movements necessary to complete the task. planned machining. During these upward and downward movements, the tool magazine is locked in rotation about the axis A, but constantly or frequently makes small rotational movements about the axis B. These movements around the axis B pose a problem when automating the replacement of a tool in the magazine, as the tool position can vary unpredictably at any time. Conventional and affordable devices to the skilled person therefore do not work.

The present invention proposes to remedy at least some of the aforementioned drawbacks and proposes a solution that makes it possible to replace a tool in the tool magazine automatically, while remaining a simple, inexpensive and very reliable solution.

To this end, the invention relates to a tool changer of a tool magazine assigned to a machining head, said tool magazine having a crown shape which has an axis of symmetry and a circumference and comprising a a plurality of tool holders disposed circumferentially and each adapted to hold a tool so that it can be automatically positioned on said machining head, and is rotatable about said axis of symmetry so as to enable position of any of the tool holders of the tool magazine at said machining head, and movable in rotation about a second substantially horizontal axis so as to allow lateral movement of the tool carrier to the tool head so that the tool head can deposit or grasp the tool. Said tool changer is particular in that it comprises a first means for holding said tool, means for opening said holding means, means for translating said holding means between a position outside the tool magazine and a position in the tool magazine, and means for adapting said position in the tool magazine to the variable position of the tool support due to movement of the tool magazine about said second axis.

Thus the automation of the tool change becomes possible, in spite of the frequent or continuous movement of the tool magazine, which makes it possible to avoid the stop of the machining center for such a tool change, and therefore of increase its operating time per day, and therefore its profitability.

According to other features: said translation means may be a carriage actuated in translation by an engagement jack, and said means for adapting a resilient means disposed between said carriage and said holding means, adapted to accommodate by its elasticity the difference between the movement of said carriage and that of said tool support, thus providing a reliable solution of movement, said elastic means may be a spring disposed between the holding means and said carriage, representing a simple and inexpensive solution, said means retaining device may be a clamp actuated by a clamping cylinder, so as to allow perfect reliability of both the maintenance and the opening, said tool changer may further comprise a second holding means for a second tool, so to allow a placement of said second tool in the tool magazine immediately after removal of a first tool from said magazine by the medium n of the first holding means, allowing a considerable saving of time, said tool changer may comprise a rotation means adapted to move the first holding means from its off-store position while putting the second holding means in said off position; store, thus allowing a rapid sequence of movements, said rotation means can be a rotary cylinder, again representing a simple and compact solution. The present invention also relates to a method of placing and / or automatically removing a tool from a tool magazine assigned to a machining head, by a tool changer 20 according to the invention, and comprising the following steps: setting up a tool on the second holding means set in off-store position of the first holding means 25 actuating the engagement jack for positioning in the magazine the first holding means, the means for holding the adaptation ensuring the correspondence of said position in the magazine with the actual position of a tool in the magazine closing the first holding means 30 actuating the engagement cylinder for setting the non-magazine position of the first holding means actuating the rotary actuator to move the first holding means away from the first holding means and to put the second retaining means in position while holding the actuating cylinder for positioning in the magazine of the second retaining means , the matching means ensuring the correspondence of said position in the magazine with the actual position of the tool support in the magazine opening of the second holding means actuating the engagement cylinder for setting the non-magazine position of the second holding means . The advantage of the present invention is that the automatic replacement of a tool of the tool magazine becomes possible by a simple, reliable, compact and inexpensive solution. The machining center can thus operate continuously, its program managing the moments when it is necessary to replace a tool for wear, where it is necessary to replace one because the planned operations require tools not present in the tool magazine, and manager. the moment when such a replacement is possible by the device according to the invention. It is then sufficient to feed the tool changer outside the machining center without stopping it, either by manual feeding, or by a power supply itself automated, according to solutions accessible to the man of the 'art. Other features and advantages of the invention will emerge from the following detailed description relating to an exemplary embodiment given by way of indication and not limitation. The understanding of this description will be facilitated with reference to the accompanying drawings, in which: FIG. 1 shows a perspective view of a tool change device according to the invention, with a tool changer in two positions; FIG. 2 represents a detail of the tool changer implanted in FIG. 1; Figure 3 shows the tool changer of FIG. 2 equipped with tools; As shown in Figures 1 to 3 of the attached drawing, the present invention relates to a tool change device in a tool magazine 1, said device comprising a positioning arm 2, movable in translation relative to to a fixed frame 3, by means of a positioning cylinder 4. On said arm 2 is fixed by a fixing bracket 5 a tool changer 6, shown in detail in FIG. 2. The tool changer 6 is facing an opening 7 of the tool magazine 1, to extract and / or install a tool 8. Such tool 8 is usually accompanied by its tool holder, which allows it to attach to the machining head (not shown) served by the tool magazine 1. In the following we pass in silence such a tool holder, and we will mention only the tool 8 to mean a tool 8 accompanied if necessary its tool holder. When the extraction or installation of the tool 8 in the tool magazine 1 is finished, the positioning cylinder 4 brings the tool changer 6 to the outside of the machine, in an area where it is permitted to intervene manually while the machining center is running. Here, it is then possible to take the tool 8 extracted, with a view to sharpening it, or to repair it, and it is possible to install another intended to be installed in the tool magazine 1 during the following operation. This operation can be done manually, but it can also be done automatically, for example by means of a second tool magazine 1, in which are disposed the next tools 8 to replace, and / or the last tools 8 extracted from tool magazine 1, thus allowing to intervene manually only after a certain number of operations of changes of tool. We understand the interest of such an installation, which avoids introducing the hand of an operator in the machining center. By replacing the hand of an operator by a mechanical arm 2 equipped with automatisms, and able to replace a tool 8 in the tool magazine 1, we can then afford to perform this operation without stopping the machining center. . Indeed, all the movements of an automated arm 2 are perfectly mastered, and the risk of collision with the machining head and its tool 8 running is almost zero. Moreover, if such a collision should happen due to a programming or design error, the damage would be exclusively material, without any risk of injury to the operator. The machining center can therefore operate continuously, without any stop for the replacement of worn or defective tools. It is nevertheless necessary to design the program of the machining center to organize the replacements of such tools, which is not easy, but is within the reach of a numerical control programmer. But we can avoid stops, and therefore increase the running time of this equipment. The tool changer 6 is hereinafter described in more detail.

This tool changer 6 comprises the fixing bracket 5, which forms the fixed part of this tool changer 6. It also comprises two clamps 9, each actuated by a clamping cylinder 10. These clamps 9 are configured to maintain a tool 8 when they are tightened by the clamping jack 10. The tool changer 6 further comprises a carriage 11 movable in translation between a position outside the magazine and a position in the magazine, and actuated by a jack d In the tool magazine 1, each tool 8 (or tool 8 with its tool holder) is held by an elastic ring 13. Thus, when a clamp 9 holds a tool 8, the clamping cylinder 10 being closed, the carriage 11 moves into position in the magazine, in a free position, and the tool 8 comes to fit in the ring 13 of this location. When the clamping cylinder 10 opens, the clamp 9 is released, and the tool 8 is then held by the ring 13 in the tool magazine 1 and the carriage 11 can return the clamp 9 in the off-store position. Conversely when a clamp 9 without tools 8, the clamping cylinder 10 being open, approaches the tool magazine 1, the carriage 11 is put in the position in the magazine at a location containing a tool 8 to extract, the clamp 9 first surrounds the tool 8, then the clamping cylinder 10 closes, so that the clamp 9 firmly holds the tool 8. When the carriage 11 returns to the off-store position, the elastic ring 13 loosens tool 8 by deforming elastically, and the tool 8 accompanies the clamp 9 closed.

The change tool changer 6 comprises a second clamp 9 with a second clamping cylinder 10. The two clamps 9 are arranged on a rotating axis, and actuated by a rotary cylinder 14. When it is desired to replace a tool 8 in the tool magazine 1, it has on the second clamp 9 the replacement tool 8, the first clamp 9 being empty. The tool changer 6 is introduced into the machine by means of the positioning cylinder 4. The first clamp 9 is introduced into the tool magazine 1 at the location from which the tool 8 to be extracted is to be removed. replace, and extract said tool 8. The carriage 11 then puts the clamp 9 in the off-store position, then the rotary jack 14 rotates the movable axis by a quarter of a turn, so as to have the second clamp 9 facing the store 1. The carriage 11 then puts the second clamp 9 in position in the magazine; it pushes its tool 8 in the ring 13 released since the first clamp 9 has extracted the tool 8 to replace. The clamping cylinder 10 of the second clamp 9 opens, then the carriage 11 returns the second clamp 9 in its off-store position. The tool replacement is then completely carried out, the positioning jack 4 can take out the arm 2 of the machine. The tool magazine 1 has a crown shape, and the tools are arranged on its circumference. It is movable in rotation about an axis A, axis of symmetry of the crown, to allow to dispose in front of the machining head the desired tool 8, in the low position of the tool magazine 1. A firm wall the tool magazine 1 on the side of the machining head, this wall not being rotatable about the axis A. It has an opening at the machining head to allow the passage of a Tool 8. There are currently 14 tool shops or 21 tools. The rotational movements of the tool magazine 1 are thus configured to allow that of the 14 or 21 tools selected to be positioned in front of the machining head. For the machining of a part, it is common to use several tools successively, milling cutters, forests, reamers, and other machining tools. The machining center is thus programmed so that a table performs all the movements of the workpiece in the horizontal direction, and the machining head performs all the movements in the vertical direction.

For tool changes, the machining head is placed in the up position, where it is in front of a tool 8 of the tool magazine 1. The machining head is not movable in the horizontal plane it is then the tool magazine 1 that must approach the machining head. It does this by a rotational movement about a horizontal axis B, the tool 8 to be disposed in the machining head at the bottom end of the tool magazine 1. This movement is configured so that the ring 13 seize the tool 8 of the machining head. At this moment the machining head opens a collet, and the tool 8 remains held by the ring 13. The tool magazine 1 is set back in position by rotation about the axis B, then revolves around the axis A until the new tool 8 is in front of the machining head. The tool 8 is held in the tool magazine 1 by the ring 13 is pushed to its position on the machining head, which then closes the clamp on the tool 8, the tool magazine 1 rotates around the axis B, so that the ring 13 releases the tool 8. In the machining phase, the tool magazine 1 makes movements around the axis B, according to the vertical position of the machining head. However no movement around the axis A is allowed in the machining phase. Movement around the A-axis is only allowed during tool change phases. To replace a tool 8 in the tool magazine 1, an opening 7 is disposed in the non-movable wall about the axis A of the tool magazine 1, on the lateral side, to a quarter turn of the position of the machining head. It is therefore possible to replace a tool 8, only when it is precisely in front of the opening 7. The machining center is programmed to handle the opportune moments, and decide when the tool 8 which must being replaced is opposite the opening 7. Due to the rotational movements of the tool magazine 1 around the axis B during machining, it is necessary that the intervention of the tool changer 6 is done. adapting to these movements, and adapting to the different possible positions of the tool 8 relative to the tool changer 6. The tool change device is configured so that the movement of the tool 8 by relative to the tool changer 6 is essentially along the axis of the engagement cylinder 12. For example we can have the axis of the engagement cylinder 12 perpendicular to the axis B.

The axis of the positioning cylinder 4 must be arranged so as to be able to enter the machining center, so there is not a large choice of directions. Nevertheless, when possible, one can choose the direction of the axis of the positioning cylinder 4 parallel to the axis B. Otherwise, it may have a slight angle with the axis B, and the fixing bracket 5 may be configured so that despite the angle between the axis of the positioning cylinder 4 and the axis B, the axis of the engagement cylinder 12 is nevertheless perpendicular to the axis B. The axis of the engagement cylinder 12 may also not be perpendicular to the B axis, the skilled person will find the solutions for the movement of the carriage 11 is able to follow the movement of the tool 8 in the tool magazine 1 during a phase d 'machining. The carriage 11 is provided with an elastic means configured to give a positional tolerance of the clamp 9 relative to the carriage 11. In this way, when the engagement cylinder 12 is actuated, the clamp 9 moves towards a ring 13 When the gripper 9 encounters the ring 13, either with a tool 8 to be deposited, or to extract a tool 8, it is possible, depending on the position of the tool magazine 1 at this precise moment, that the carriage 11 did not finish his race. The elastic means then allows the engagement cylinder 12 to complete its stroke, while the clamp 9 remains stationary. This elastic means may be a spring arranged at the end of travel of the carriage 11, configured stiff enough to engage a tool 8 in the ring 13, but sufficiently flexible to then compress and allow the clamp 9 to remain stationary, or to follow the movement of the ring 13, while the carriage 11 continues and ends its race. This elastic means also makes it possible for the extraction or installation operation of a tool 8 to take place while the tool magazine 1 is in the process of making rotational movements around the axis B, for the needs vertical movements of the machining head. The elastic means absorbs the differential movement between the ring 13 and the carriage 11, so that the clamp 9 can remain attached to the ring 13 all the time necessary to perform the installation or extraction of a tool 8. In all the rigor the movement of the ring 13 is a circular movement of rotation about the axis B, while the movement of the carriage 11 is rectilinear. However, the difference between the two movements is small, because of the small amplitude of this movement with respect to the radius of the circular motion. Indeed, the tool magazine 1 makes a significant rotational movement about the axis B at the moment when the machining head makes a tool change, but during the replacement of a tool 8 by the tool changer 6, the machining head is being machined, and the rotational movements of the tool magazine 1 about the B axis are lower. Moreover, the elastic means can be configured to also absorb the differences between the rectilinear movement of the carriage 11 and the circular movement of the ring 13, and therefore of the clamp 9 during the time when it is in contact with the ring 13 by the intermediate of the tool 8 to be extracted or installed, even if said differences comprise a component of movement perpendicular to the axis of the engagement cylinder 12. The advantage of the present invention resides in particular in that Although the invention has been described with respect to a particular embodiment, it is understood that it is in no way limited and that various modifications of shapes, materials and combinations of these various elements can be made therein without departing from the framework and spirit of the invention.

Claims (8)

REVENDICATIONS1. Tool changer (6) of a tool magazine (1) assigned to a machining head, said tool magazine (1) having a crown shape which has an axis of symmetry (A) and a circumference and comprising a plurality of tool supports (13) disposed circumferentially and each adapted to hold a tool (8) so that it can be automatically positioned on said machining head, and rotatable about said axis of symmetry so as to allow positioning of any one of the tool supports (13) of the tool magazine (1) at said machining head, and mobile in rotation about a second axis (B) substantially horizontal so as to allow lateral displacement of the tool support (13) towards the machining head so that the machining head can deposit or grasp the tool (8), characterized in that it comprises a first holding means (9) of said tool (8), an opening means (10) for said holding means ien (9), a means (11) for translating said holding means (9) between an out-of-magazine position and a position in the magazine, and means for adapting said position in the magazine to the variable position of the support tool (13) due to movement of the tool magazine (1) about said second axis (B). Tool changer (6) according to the preceding claim 25, wherein said translating means is a carriage (11) actuated in translation by an engagement cylinder (12), and said adaptation means is an elastic means disposed between said carriage (11) and said holding means (9), able to cash by its elasticity the difference between the movement of said carriage (11) and that of said tool carrier (13). 3. Tool changer (6) according to the preceding claim, wherein said resilient means is a spring disposed between the holding means (9) and said carriage (11). 4. Tool changer (6) according to one of the preceding claims, wherein said holding means is a clamp (9) actuated by a clamping cylinder (10). 5. Tool changer (6) according to one of the preceding claims further comprising a second holding means (9) for a second tool (8), so as to allow a placement of said second tool (8) in the tool magazine (1) immediately after removing a first tool (8) from said tool magazine (1) by means of the first holding means (9) 6. tool changer (6) according to the preceding claim, comprising a rotating means (14) adapted to move the first holding means (9) from its off-store position while putting the second holding means (9) in said off-store position. 7. Tool changer (6) according to the preceding claim, wherein said rotation means is a rotary jack (14). 8. A method of placing and / or automatically removing a tool (8) from a tool magazine (1) assigned to a machining head, by a tool changer (6) according to the claim 7, and comprising the following steps: placing a tool (8) on the second holding means (9) placed in the out-of-magazine position of the first holding means (9) actuating the engagement jack (12) for positioning in the magazine the first holding means (9), the adjusting means ensuring the correspondence of said position in the magazine with the actual position of a tool (8) in the tool magazine (1). ) closing the first holding means (9) 30 actuating the engagement cylinder (12) for positioning the first holding means (9) out of the magazine (9) actuating the rotary jack (14) to move away from the first holding means (9) ) and placing in non-store position the second holding means (9) actuating the engagement jack (12) for setting the positio n in the magazine of the second holding means (9), the matching means ensuring the correspondence of said position in the magazine with the actual position of the tool support (13) in the tool magazine (1) opening of the second holding means (9) actuating the engagement cylinder (12) for setting the second holding means (9) out of the storage position.