FR2496531A1 - Holder for machine tool - has tool driven along curved path w.r.t. axis of machine tool spindle using geared ring driving spindle - Google Patents

Abstract

The tool holder includes a ring with an axis coinciding with the axis of a machine tool, which has a spindle driving a shaft on the axis in the ring (a). The shaft (b) has gear teeth driving a gear ring with an axis which is displaced w.r.t. the first axis. The gear ring has internal teeth driving a spindle on a third axis and a tool, e.g. a milling cutter, is located in the spindle. The gear ring is located in a housing, which is rotated on the ring by a worm and wormwheel. The result is that the spindle travels through an arc w.r.t. the axis, esp. so the tool can cut a curved groove in a workpiece.

Description

Tool holder device in particular for a universal type of machine tool making it possible to produce machining operations such as arcuate grooves.

 The present invention relates to a tool holder device for a machine tool of a universal type for performing such machining such as arcuate grooves.

 When it is desired to create a seal between two parts having, in particular, radial annular contact surfaces and fastening elements such as bolts which pass through the contact surfaces, it is customary to make grooves in the contact surface. one of the parts and arrange a seal in this groove. The realization of such grooves poses certain difficulties, especially when it is necessary to circumvent the holes through which the fasteners pass.

Currently, this problem is solved by machining the grooves in the form of broken lines or using the numerical control. However, the production of grooves in broken lines without numerical control is expensive because it requires adjustment times of the machine tool and the important workpiece. In addition, few companies have a numerically controlled machine tool because such a machine requires a very large amount of fun.

 The present invention aims to overcome the disadvantages of the technique. It allows in particular the realization of grooves at a very low cost of machining while avoiding numerical control.

 The tool holder according to the present application can be mounted on a machine tool of universal type such as a milling machine or a boring machine and can transmit the movement of the output shaft of the machine tool to the tool and to perform particular machining such as arcuate grooves of different radii and different arcs.

 For this purpose, the tool holder according to the invention comprises a support which can be fixed to the body of or on the machine tool and having a main axis, a housing mounted on said support so as to be able to rotate around the main axis of this support and having a secondary axis different from said main axis, a spindle sleeve rises on said housing so as to be rotatable about the secondary axis of this housing, a tool pin carried by said spindle sleeve being rotatable about an axis different from the secondary axis of said holder sleeve, a gear transmission comprising gear elements rotating about said axes and effecting the transmission of the movement of the output shaft of the machine tool at said spindle for rotating said tool, an adjusting means for rotating said spindle sleeve about said secondary axis by rolling a su r the other two elements of the last gear of said gear transmission, one of which is associated with said pin and the other is mounted along said secondary axis to adjust the desired spacing between the axis of said pin and said axis main and driving means for rotating said housing relative to said support so as to perform the desired arcuate machining whose main radius is equal to the spacing between the axis of said pin and said main axis .

 In an interesting variant embodiment, said transmission comprises a main shaft mounted along said main axis and comprising means of connection with the output shaft of the machine tool and a toothed part and a secondary shaft mounted along said secondary axis and comprising a first toothed portion engaged with the toothed portion of said main shaft and a second toothed portion engaged with a toothed portion of said tool pin, the second toothed portion of said secondary shaft and the toothed portion of said tool pin forming said last gear .

 According to the present invention, said last gear may comprise a toothed wheel and an inner toothed crown.

It may also include two gears.

 According to the present invention, said main shaft can be mounted in alignment with the output shaft of the machine tool, said connecting means being formed by an axial connecting element fixed to the end of said main shaft and cooperating with the end of the output shaft of the machine tool.

 According to the present invention, said holder sleeve may comprise at its periphery a toothed portion centered along said secondary axis. A toothed gear can be rotatably mounted on said housing and engage with the peripheral toothed portion of said spindle sleeve, said pinion gear being rotatable to rotate said spindle sleeve relative to said housing about said minor axis, said pinion and said peripheral toothed portion of the spindle sleeve forming said adjusting means.

 According to the present invention, said drive means may comprise an input shaft mounted on said support and a gear link between said input shaft and said housing, said input shaft being connectable to an external means such as an electric motor so as to rotate said housing about said main axis.

In a preferred embodiment, said gear link comprises a toothed wheel fixed to said casing and centered along said main axis and a screw-shaped part made or mounted on said input shaft which is arranged transversely to said gear wheel.
The device according to the present invention preferably comprises means for releasably securing said spindle sleeve to said housing after having made the desired adjustment and in particular to avoid, during machining, vibrations or a modification of the adjustment .

 The tool-holder device may also comprise means for releasably securing said casing to said support, in particular when grooves are made in straight lines without rotating the casing with respect to said support around said main axis.

 Preferably, said casing is mounted on said support by means of at least one bearing centered along said main axis. In addition, the elements of said gear transmission are preferably mounted by means of bearings centered along said main axis, said secondary axis and the axis of said tool spindle.

The present invention will be better understood by studying a tool holder device described by way of nonlimiting example and illustrated by the drawing on which
- Figure 1 shows the tool holder in section;
and Figure 2 shows the It-Ti section of the tool holder of Figure 1.

 The tool holder shown in the figures and generally indicated by the reference numeral 1 can be mounted on a machine tool of a universal type such as a milling machine or a boring machine.

 It comprises a support 2 consisting of a cylindrical part 3 which has a main axis 4 in alignment with the axis of the output shaft of the machine tool which has not been shown and a radial flange 5 fixed to the rear part of the machine. the cylindrical portion 3 by screws 6. The flange 5 has a central passage 7 as well as peripheral holes B external to the cylindrical portion 3 for the passage of screws for fixing the support 2 to the housing or the head of the machine- tool.

 The tool holder 1 also comprises a housing 9 which has a disk-shaped radial portion 10 whose rear portion is in contact with the front radial face 11 of the cylindrical portion 3 of the support 2, a cylindrical portion 12 centered on the main axis 4 and extending from the radial disk-shaped portion 10 on the one hand to Lavant and on the other hand rearwardly within the cylindrical portion 3 of the support 2 to provide a passage cylindrical 12a centered along the main axis 4 passing through the radial portion 10 and a cylindrical portion 13 having a diameter greater than the diameter of the cylindrical portion 3 of the support 2 and extending forwardly from the radial portion disk-shaped 10.

 The casing 9 also comprises a radial cover 14 which is fixed on the front face of the cylindrical part 13 by screws 15.

The housing 9 determines a secondary axis 16 different from the main axis 4 and parallel thereto.
The cover 14 of the housing 9 comprises a cylindrical opening 17 centered on the secondary axis 16.

 The casing 9 is rotatably mounted around the main axis 4 relative to the support 2 by means of a special high-strength and high-precision bearing 18, this bearing 18 being mounted around the rear part of the cylindrical part. 12 of the housing 9 and fixed on the radial portion 10 of the housing 9 by axial screws 19 and on the inner front portion of the cylindrical portion 3 of the support 2 by axial screws 20.

 The tool holder shown also comprises a spindle sleeve 21. Ct spindle sleeve 21 comprises a radial portion 22, a cylindrical portion 23 which extends rearwards and a cylindrical portion 24 of a smaller diameter which extends forwardly, the disc 22 making the connection between the cylindrical portions 23 and 24.

The cylindrical portion 23 of the spindle sleeve 21 has on the outside an annular shoulder 25 so that the rear end portion of the cylindrical portion 23 enters the cylindrical opening 17 of the housing 9 and that the rear face of the annular shoulder 25 come into contact with the front face of the cover 14 of the housing 9.The pin-holder sleeve 21 thus enters the opening 17 of the cover 14 and can rotate along the secondary axis 16. pin 21 is also maintained by means of an annular ring 26 of L-shaped section which is fixed to the front face of the cover 14 of the housing 9, the annular shoulder 25 being disposed between the front face of the cover 14 and the radial portion of the ring 26 with game,
The cylindrical portion 24 of the spindle sleeve 21 accommodates a cylindrical passage 27 in which is mounted a substantially cylindrical pin 28 by means of two bearings 29 and 30 so that the axis 31 of this pin 28 is parallel to the secondary axis 16 and off-center with respect thereto.The front portion of the pin 28 is designed to be able to receive a tool such as a milling cutter which has not been shown in the figure. For this purpose, the front part of the pin 28 comprises a frustoconical blind hole 32 and a tool attachment nut 33 is screwed on the front end of the pin 28, the axis of the tool being arranged according to the pin 31 of pin 28.

 The tool holder device shown in the figures also comprises a gear transmission generally indicated by the reference 34 and mounted inside the support 2 of the housing 9 and the toolholder sleeve 21.

 The gear transmission 34 comprises a main shaft 35 mounted along the main axis 4 and extending into the central passage 12a of the housing 9. The rear portion of the main shaft 35 has axial outer ribbings 36 and carries a housing element. link 37 having corresponding inner ribbing, this connecting element 37 being known to be connected quickly to the end of the output shaft of the machine tool on which the device 1 through the central passage 7 of the flange 5 of the support 2, the main shaft 35 being in alignment with the output shaft of the machine tool. For this purpose, the rear part of the connecting element 37 comprises a central cylindrical recess 38 and a radial groove 39.

 The shaft 37 is mounted along the main axis 4 in the central passage 12a of the cylindrical portion 12 of the housing 9 by means of a bearing 40 which is supported on the one hand on the shaft 35 and on the other hand on the part before the cylindrical portion 12 and a bearing 41 which is supported on the one hand on the inner rearwardly cannulated portion of the connecting element 37 and on the other hand on the rear portion of the cylindrical portion 12, a washer 35a fixed to the end of the shaft 35 and disposed in the recess 39 now the assembly.

 The main shaft 35 extends into the housing 9 forwardly beyond its cylindrical portion 12 and comprises, at its front entrance, an external toothing 42.

 The gear transmission 34 also comprises a secondary shaft 43 mounted along the secondary axis 16 and disposed in the housing 9. The secondary shaft 43 is double toothed and comprises an external toothing 44 engaged with the toothing 42 of the shaft main 35 and an internal toothing 45 forming a ring gear with internal teeth.

This internal toothing 45 is made in a central recess 46 of the secondary shaft 43, this recess being open on the front side.

The teeth 44 and 45 of the secondary shaft 43 are centered along the secondary axis 16.

 The rear portion of the spindle 28 extends to the inside of the recess 46 of the secondary shaft 43 and has an external toothing 47 which is engaged with the internal toothing 45 of the secondary shaft 43. diameter of the toothing 47 of the pin 28 is, in the example shown, substantially equal to one third of the diameter of the internal toothing 45 of the secondary shaft 43.

 The secondary shaft 43 is mounted along the secondary axis 16 by means of a bearing 48 mounted on the one hand on the rear part of the secondary shaft 43 and on the other hand in a recess 49 open towards the front made in its radial disc-shaped portion 10 of the housing 9 and further thanks to a bearing 50 mounted at the front of the toothing 44 between the front portion of the secondary shaft 43 surrounding the internal toothing 44 and the cylindrical portion 27 of the bearing sleeve -broche 21.

 The tool holder 1 also comprises a setting means generally indicated by the reference 51.

This adjustment means 51 is formed by a toothing 52 made at the periphery of the shoulder 25 of the spindle sleeve 21 and a shaft 53 which has a toothing 54 in engagement with the toothing 52 and inserted into the retaining ring 26. Spindle sleeve 21. The rear portion of the shaft 53 is rotatably mounted and centered in an orifice 55 of the cover 14 of the housing 9 via a friction ring 56 and the front portion of the shaft 53 extends through and beyond the ring 26 and has a square section that can receive a key or crank not shown.

 The tool holder device 1 also comprises a means for releasably securing the tool sleeve 21 to the housing 9. This means is formed by locking pieces 57 mounted in recesses of the ring 26 regularly distributed.

These locking pieces 57 are fixed to the axial part of the ring 26 by screws 58 which, when tightened, allow the locking pieces 57 to press on the shoulders 25 of the spindle sleeve 21 to apply it. against the front face of the cover 14 of the housing 9.

 The tool-holder device 1 also comprises a drive means generally indicated by the reference numeral 59 enabling the housing 9 to be rotated relative to the support 2.

This drive means 59 comprises a ring 60 fastened to the rear end of the cylindrical portion 12 of the casing 9 by screws 61 and having an external toothing 62 centered along the main axis 4.

 As can be seen more clearly in FIG. 2, the driving means 59 also comprises a transverse input shaft 63 which carries a worm screw 64 in engagement with the toothing 62 of the ring 60.

 The input shaft 63 is mounted via needle bearings 65 and 66 in a sleeve 67 which is disposed in a transverse opening 68 of the cylindrical portion 3 of the support 2 and fixed to this cylindrical portion 3 by means of axial screws 69.

Needle bearings 65 and 66 are associated with axial thrust bearings 70 and 71 which bear respectively against the worm 64 held by a nut 72 screwed onto the inner end of the input shaft 63 and against a shoulder 73 of the input shaft 63.

the abutments 70 and 71 being further bearing against opposite shoulders of the sleeve 67.

 The output shaft 63 extends outside the sleeve 67 and the support 2 and its outer end has a square section 74. An electric drive motor 75 shown schematically and partially at its output shaft 76 aligned with the input shaft 63 and rotatably connected to the latter by a connecting element 77. The electric drive motor 75 can be fixed either directly on the support 2 or to the machine tool.

 The tool holder device 1 also comprises a locking means for detachably rotating the housing 9 to the support 2. This locking means comprises screws 78 distributed on the periphery of the cylindrical portion 3 of the support 2 which passes through bushings 79 arranged in orifices 80 of an outer radial extension 81 of the front portion of the cylindrical portion 3 of the support 2. The threaded end of the screws 78 cooperates with nuts 82 which are arranged in a dovetail ring 83 formed in the rear face of the disk-shaped radial portion 10 in contact 11 with the cylindrical portion 3 of the support 2. The sockets 79 are arranged between the rear face of the housing 9 and the head of the screws 78. As an example, three locking screws 78 are provided.

The tool-holder device 1 also comprises an annular rule placed in a circumferential groove of the cylindrical part 3 of the support 2 adjacent the housing 9, this rule being able to turn and being able to be locked on the support 2 by means of a radial screw 85. This graduated rule 84 makes it possible to know the variation of angular position between the casing 9 and the support 2,
It is also provided on the ring 26 and on the sleeve-boh-21 bore graduations to know either the angular position of the spindle sleeve 21 relative to the housing 9 is directly the spacing between the main axis 4 and the axis 31 of the tool spindle 28.

 Finally, the tool holder device 1 comprises a deflector 86 fixed on the inner face of the flange 5 around the central passage 7 and which extends towards the periphery of the connecting element 37, an annular lip seal 87 between the portion of the cylindrical portion 12 of the housing 9 and the connecting member 37, an O-ring 88 mounts in a peripheral groove of the cylindrical portion 23 of the spindle sleeve 21 and in contact with the cylindrical opening 17 of the lid 14 and an annular lip seal 89 mounted in a ring 90 fixed to the front face of the cylindrical portion 24 of the spindle sleeve 21 by screws 91 and in contact with a front peripheral surface of the pin 28, said baffle and said seals being provided for the maintenance of lubricant transmissions 34 and 59 and their protection.

 We will now describe how can be used the tool holder device described with reference to Figures 1 and 2.

 The tool holder 1 is mounted on the housing or on the head of a universal type of machine tool such as a milling machine or mortiser by arranging the main shaft 35 in alignment with the output shaft of the machine. the machine tool, 11 connecting member 37 effecting the rotational connection between the output shaft of the machine tool and the main shaft 35. is mounted in the pin 28 a tool such as a milling cutter.

 The rotational movement of the output shaft of the machine tool is transmitted to the tool via gearing 34.

 To make a groove in a straight line on a part placed in front of the tool mounted in pin 287 it suffices to operate as usual by moving either the head of the machine tool or the workpiece. It is good to have taken care before making this machining to lock the screws 58 to secure the spindle sleeve 21 to the housing 9 and to block the screws 78 to secure the housing 9 to the support 2.

 To make a groove having a determined main radius, the spacing between the delta pin axis 31 which corresponds to the axis of the tool and the main axis 4 to the desired radius is adjusted by rotating the shaft 53 which, thanks to its toothing 54, rotates the spindle sleeve 21 around the secondary axis f6.

 During the rotation of the spindle sleeve 21, the toothing 47 of the spindle 28 rolls on the internal toothing 45 of the secondary shaft 43 fixed. When this adjustment is made, the spindle sleeve 21 is preferably secured to the housing 9 by blocking the screws 58. To perform the machining of the groove according to the desired radius, and after taking care that the screws 78 are 011 unlocks the machine tool which then drives the tool through the gear transmission 34 and starts the drive motor 75 which, through the worm 64 and the outer ring gear 60, rotates the housing 9 about the main axis 4 and thus determines the feed movement of the tool The arc covered by machining can be any.

 it is obviously possible to continuously perform straight grooves and grooves arcuate.

 According to the example shown, grooves can be made in an arc whose maximum radius is equal to the distance between the main axis 4 and the secondary axis 16 to which is added the difference between the main radius of the toothing 45 of the secondary shaft 43 and the main radius of the toothing 47 of the spindle 28 whose minimum radius is equal to the distance between the main axis 4 and the secondary axis 16 to which the difference between the radius is subtracted of the toothing 45 of the secondary shaft 43 and the main radius of the toothing 47 of the spindle 28. All the intermediate radii are possible.

 Given its structure, the tool holder device 1 which has just been described is not bulky and is very robust.

Indeed, its gear transmission 35 can transmit to the spindle 28 the engine torque of the output shaft of the machine tool and its drive device 59 also gearing allows the usual feed rates.

 The present invention is not limited to the tool holder device described above with reference to Figures I and 2. It can in fact be designed including a different gear transmission.

 and in particular a secondary shaft comprising two outer teeth, one being taken with the external toothing of the pin 28.

The structure of the gear transmission could in particular depend on the speed ratio between the spindle 28 and the output shaft of the machine tool and the maximum and minimum radii of the grooves that one would like to machine. It may further be noted that the tool device could also be used to machine only contours with arcs.

 Many other variants of the tool holder device according to the present invention are also possible without departing from the scope of the present invention.

Claims (12)

 1. A tool-holder device that can be mounted on a machine tool of a universal type such as a milling machine or a boring machine and for transmitting the movement of the output shaft of the machine tool to the tool and of particularly perform machining such as arcuate grooves of different radii and different arcs, characterized in that it comprises a support that can be fixed on the body of the machine tool and having a main axis a mounted casing on said support so as to be rotatable about the main axis of said support and having a secondary axis dif ferent of said main axis, a holder sleeve rises on said housing so as to be rotatable about said secondary axis, a pin-holder tool carried by said spindle sleeve so as to be rotatable about an axis different from said secondary axis, a gear transmission comprising toothed elements rotating about said axes and performing the transmission of the movement of the output shaft of the machine tool to said spindle to rotate said tool, an adjusting means for rotating said spindle sleeve about said secondary axis by rolling one on the other the two elements of the last gears, one of which is associated with said pin and 11 other is mounted along said secondary axis to adjust the desired spacing between the axis of the pin and said main axis, and a means of drive for rotating said housing relative to said support so as to perform the desired arcuate machining whose main radius is equal to the spacing between said main axis and the axis of said pin.  2. A tool holder according to claim 1, characterized in that said gear transmission comprises a main shaft mounted along said main axis and having means for connection with the output shaft of the machine tool and a toothed part and a shaft secondary member mounted along said secondary axis and having a first toothed portion engaged with the toothed portion of said main shaft and a second toothed portion engaged with a toothed portion of said tool pin, the second portion of said secondary shaft and the toothed portion of said tool spindle forming said last gear.  3. A tool holder according to claim 2, characterized in that said main shaft is in alignment with the output shaft of the machine tool, said connecting means being formed by an axial connecting member fixed to the end of said main shaft and cooperating with the end of the output shaft of the machine tool.  4. Tool-holder device according to any one of the preceding claims, characterized in that said last gear comprises a toothed wheel and an inner ring gear.  5. A tool holder according to any one of claims 1 to 3, characterized in that said last gear comprises two gear wheels.  6. Tool-holder device according to any one of the preceding claims, characterized in that said spindle sleeve comprises at its periphery a toothed portion centered along said secondary axis and a toothed gear is rotatably mounted on said housing and engages with the peripheral toothed portion of said spindle sleeve, said pinion gear being rotatable to rotate said holder sleeve relative to said housing about said minor axis, said pinion and said peripheral tooth portion of the spindle sleeve forming said adjusting means.  7. Tool holder according to any one of the preceding claims, characterized in that said drive means comprises an input shaft mounted on said support and a gear connection between said input shaft and said housing, said input shaft being connectable to an external means such as an electric motor so as to rotate said housing about said main axis.  8. A tool holder according to claim 7, characterized in that said gear link comprises a gear wheel fixed to said housing and centered along said main axis and a screw-shaped portion formed or mounted on said gear shaft. input which is disposed transversely to said gear wheel.  9. Tool-holder device according to any one of the preceding claims, characterized in that it comprises means for releasably securing said pin holder sleeve to said housing.  10. Tool holder device according to any one of the preceding claims, characterized in that it comprises means for releasably securing said housing to said support.  11. A tool holder according to any one of the preceding claims, characterized in that said cartE is mounted on said support via at least one bearing  12. Tool holder device according to any one of the preceding claims, characterized in that the elements of said gear transmission are mounted by means of bearings.