FR2546091A1 - INTERCHANGEABLE TOOL SUPPORT UNIT FOR MACHINE - Google Patents

Abstract

THE INVENTION RELATES TO AN INTERCHANGEABLE TOOL SUPPORT UNIT FOR A MACHINE INTENDED TO SUPPORT A WORKING ELEMENT. THE UNIT INCLUDES A GENERALLY EXTENDED ROTARY BODY 1, ONE END OF WHICH IS CONNECTED TO A ROTATING CONTROL SOURCE 48, A TOOL HOLDER 4 CARRIED BY ROTARY BODY 1 TO EXECUTE MOVEMENT IN A RADIAL DIRECTION AND TO SUPPORT ONE 'MACHINING 53 HAS ONE OF ITS OPPOSITE ENDS TO ROTARY BODY 1, A MOVABLE ELEMENT 24 DOES INSIDE THE ROTARY BODY 1, A CAM 21 TRANSMITTING THE AXIAL DISPLACEMENT OF THE ELEMENT 24 TO THE TOOL HOLDER 4 TO MOVE THE LATTER IN A RADIAL DIRECTION, AND AN INDEXING MECHANISM 18 TO INTERMITTENTLY MOVE THE ELEMENT 24 IN AN AXIAL DIRECTION EVERY TIME THE ROTARY BODY HAS ROTATED A FULL ROTATION. APPLICATION TO MOUNTING ON MACHINE TOOLS, IN PARTICULAR DRILLS, GRINDERS, AND LATHES.

Description

The present invention generally relates to a machining apparatus

  digitally controlled, such as for example a lathe device, a grinding machine, a punching machine, a cutting machine, and a milling machine and in particular an interchangeable tool holder unit for use in such apparatus for supporting a rotary device cutter that can be used to form a bore of a specific size

  or an O-ring seat within this bore.

  The machine tool support unit comprises a generally elongate rotating body adapted to be interchangeably coupled to a machine shaft for rotation therewith, the free end thereof having a carrier tool that

  can move in a radial direction.

  the tool support is moved together with the rotating body during rotation of the rotating body to allow a cutting element mounted in the vicinity of the

  tool holder to rotate around the longitudinal axis -

  of the rotary body so that the tool support can be moved in a radial direction relative to the rotary body In this machine tool support unit, the distance over which the tool support is radially displaced each time the machine is moved. rotary body makes a complete revolution around its longitudinal axis driven by the shaft of the machine must necessarily be very small, for example of the order of one thousandth of

  millimeter and, in addition, the tool support unit itself

  same must have a precise shape Therefore, the unit

  tool holder must contain a complicated mechanism.

  A very reliable, durable and accurate tool support unit has not been developed so far

  being that the above requirements must be met

  above. Accordingly, the present invention has been provided for the purpose of providing a machine tool support unit satisfying the requirements set out above and its main object is to provide an improved machine tool support unit in which the The tool carrier can be moved in a radial direction relative to the rotating body at an extremely small distance during a complete revolution of the rotating body so as to allow a workpiece to be machined precisely, that is, to say to form a bore of

  precise dimensions or an O-ring seat in the

inside the bore.

  Another object of the present invention is to provide an improved machine tool support unit of the type mentioned above which can be manufactured

  with a minimum number of component parts.

  Another object of the present invention is an improved machine tool support unit of the type mentioned above in which an indexing means is constructed for the purpose of moving the tool support in a radial direction with respect to the rotating body to allow the tool support unit

  to be moved gently and precisely.

  Other features and benefits of the

  present invention will result from the detailed description

  which will follow of preferred embodiments of the invention.

  FIG. 1 is a sectional side view of an interchangeable machine tool support unit according to a first preferred embodiment of the present invention;

  FIG. 2 is a view in transverse section

  dirty of the tool support unit shown in Fig. 1 to show the relationship between a follower pin and a travel wedge both used in the tool support unit;

  FIG. 3 is a longitudinal section view.

  dinaling a portion of the tool support unit to show the relationship between a tool carrier and an indexing mechanism; Figure 4 is a spread view of the indexing mechanism; Fig. 5 is a spread view showing a modified form of the indexing mechanism; Fig. 6 is a view similar to Fig. 1 to show another preferred embodiment of the present invention; Figure 7 is a longitudinal sectional view on a somewhat larger scale showing the

  relationship between the tool support and the indexing mechanism

  used in the tool support unit according to the

  second preferred embodiment of the present invention.

  vention; Figures 8 and 9 are axial sectional views respectively showing how the traveling wedge is supported when used in the tool support unit shown in Figure 6; Fig. 10 is a schematic side view of an essential portion of the tool support unit according to the embodiment shown in Fig. 1, to show the details of the moving wedge in relation to roller elements; Figure 11 is a side view of the moving wedge and roller elements in the assembled state; Fig. 12 is a perspective view of a roller assembly used in the tool support unit according to the embodiment of Fig. 6; Fig. 13 is a perspective view of a retaining member for retaining the roller members used in the tool holder according to the embodiment of Fig. 6; and Figures 14 to 16 are respective views

  fragmentary longitudinal sections of an essential part

  of the tool support unit to show different ways of movably mounting the support

tool on the rotating body.

  Before the beginning of the description of forms

  In accordance with the present invention, it will be appreciated that to describe it, it will be agreed that the interchangeable machine tool support unit according to the present invention will be used to support a cutter bit to obtain a precise bore. to finish

  a hole already drilled and give it a precise dimension.

  With reference first to FIGS. 1 to 3, it will be seen that an interchangeable machine tool support unit according to a first preferred embodiment of the present invention comprises a body

  generally elongated rotating wheel 1 having a cross section

  and a carriage section 1b to support a tool support 4, the carriage section 1b being rigidly connected to the driving section 1a to rotate together with it by means of at least one stop pin and A connecting bolt 6 The driving section 1a comprises a circumferentially grooved ring 2 rigidly mounted on this section so as to contact

  handling arm (not shown) at the time of replacement

  the tool support unit, which can be done automatically as is well known to those skilled in the art, and a rod 3 tapered outwardly from the ring 2 in a coaxial position with respect to that and intended to be removably connected to a machine shaft 48 to rotate with it, the machine shaft 48 being rotatably supported by a machine headstock 50 by a bearing assembly 49 A support shaft 7 is mounted

  externally on the trolley section lb through the

  8 axially spaced apart, the rotating body 1 rotatably passing therethrough and having a protruding lateral portion 7a.

  matter with him and in such a way as to extend radi-

  outwardly, the protruding part 7a receiving

  an air supply tube 9 in the manner described above.

  below. The air supply tube 9 has an end portion inserted axially by sliding in an inner sleeve 11 received in a bore 10 which is defined

  in the projecting lateral portion 7a so as to extend

  in the axial direction parallel to the longitudinal axis of the rotating body 1 The air supply tube 9 also serves as a positioning element to prevent any possible rotation of the support shaft 7 by

  relative to the rotating body 1 and, for this purpose, the feed tube

  9 has a plug 12 mounted externally on it and adjustably held in position by means of a locking nut 14 and a set screw 13, the plug 12 extending radially outwardly from the tube 9 Thus, it can easily be seen that by adjusting the locking nut 14, and the adjusting screw 13, the position of the plug 12 relative to the

  to the air supply tube 9 can be adjusted.

  The inner sleeve 11 within the hole in the projecting lateral portion 7a is normally pushed outwardly by means of

  a thrust spring 15 contained within the beam

  wise 10, an outer end of the inner sleeve 11 abuts therefore against the plug 12 The latter penetrates with a certain clearance in a cavity 16 defined in the support drum 7 but when, and as long as, the air supply tube 9 and the inner sleeve 11 protrude outwards under the action of the spring of

  thrust 15 to take a protruding position

  in the position set back from Figure 1), the

  chon 12 enters a cavity 17, defined in the driving section la of the rotary body 1, which allows

  to lock the support shaft 7 on the rotary body 1.

  The carriage section lb of the rotating body 1

  has a radial hole in which an indexing mechanism

  The movable drive member 18 includes an externally threaded shaft 18a, rotatably supported but not axially movable within the hole. radial formed in the carriage section lb by means of two spaced bearings 19, a toothed wheel or a spider rigidly attached to one end of the threaded rod 18a, and an indexing cam 21 internally threaded and mounted on the threaded rod 18 The indexing cam 21 has a defined cam inclined face 22 and a keyway 23 defined in the cam face 22 so as to extend in a direction parallel to the longitudinal axis of the threaded rod 18. a, the keyway 23 receiving a key projection 26 supported by a generally elongate moving wedge 24, as described below, so that the indexing car 21 can isse only move axially relative to the rod

  threaded 18 without being turned relative to the latter.

  The generally elongated travel wedge 24 is located within an axial hole of the carriage section 1b at a location between the indexing cam 21 and the tool support 4 to effect movement in an axial direction. relative to the rotary body 1 and comprises, as best shown in Figures 3 and 4, an end inclined at 25 in a direction opposite to the inclination of the cam face 22 of the indexing cam 21 to obtain a contact sliding with the cam face 22, the projecting key portion 26 protruding axially outwardly from the inclined end face 25 This wedge 24 is normally pushed by a thrust spring 27 so that its face inclined end 25 is held in sliding contact with the

  cam face 22, the thrust spring 27 being

  placed between a shoulder 28, defined in the corner of displacement

  24 and a fixed spring retainer 30

  at the trolley part lb by means of an adjustment bolt 29.

  As best shown in FIGS. 2 to 4, the tool support 4 having a cavity 4 defined to open in a direction opposite to the rotary body 1 comprises a closed end having a dovetail groove 31 extending in its radial direction, this groove 31 allowing the tool support 4 to be coupled to the carriage section 1b of the rotating body 1 and supported by it to effect a movement in a radial direction relative to the body The tool holder 4 also has a follower pin 32 which supports it so that it passes through the dovetail slot 31, the follower pin 32 having a flat contact face 33 defined therein. follower pin 32 thus being supported by the tool support 4 so as to pass through the dovetail groove 31 in the manner described above, its flat contact face 33 is kept constantly in contact with an inclined cam face 34 dice finished in the travel wedge 24 at one end thereof which is opposite the inclined end face 25 The constant sliding contact between the cam face 34 in the traveling wedge 24 and the flat contact face 33 is performed by the use of a thrust force exerted by a spring 37 which is interposed between the follower pin 32 and a plug member 36 which is screwed into a projecting and dovetailed portion 35 of the trolley section. In practice, the spring force of the spring 37 is transmitted to the follower pin 32 by means of a pusher 38 having a head

  generally conical inserted into an indentation corresponding to

  weight 39 defined in the follower pin 32.

  As best shown in Figures 1, 4

  and 5, the support shaft 7 carries a drive spindle

  40 received in a hole of the projecting lateral portion 7a so as to extend in a direction orthogonal to the axis of rotation of the rotary body 1, one of its ends being placed in the vicinity of the rotation path of the pinion 20 around the longitudinal axis

  rotating body 1, this rotation resulting from rotation

  1, and at a location permitting contact with one of the sprocket teeth 20. This drive spindle 40 can move axially between recessed and protruding positions and is normally pushed to the retracted position by a spring 41, but is moved to the projecting position against the spring 41 when a pressure is introduced into a working chamber 42 which is in fluid connection through an orifice 43 defined in the inner sleeve 11 with

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  an air chamber 44 defined in the projecting lateral portion 7 has in communication with the air supply tube 9 It should be noted that to allow the adjustment of the externally threaded rod 18a and consequently the adjustment of the position of the indexing cam 21 relative to the threaded rod 18a at the moment for example of the initial start of the machine, one end of the externally threaded rod 1 Its neighbor of the pinion 20 comprises an axial blind hole 44 for receiving the tip of the an adjusting instrument, for example a screwdriver that can access it through an access port 46 defined in the support case 7 and normally closed by a plug 47 at a location approximately circumferentially opposite to

the projecting lateral part 7 a.

  The operation of the machine tool support unit will now be described with respect to the embodiment of the present invention with reference to

Figures 1 to 5.

  After introduction of the tool 54 having a cutting bit 53 rigidly in the cavity 4a of the tool support 4, as shown in the dashed line of FIG. 1, in a known manner, the rotary body 1 carrying the tool 54 is coupled to the doll

  of the machine, the rod 3 thereof being received firmly

  Within the shaft 48 of the machine When the rotary body 1 is connected with the machine headstock 50, it is necessary to allow the free end of the air supply pipe 9 to be connected in fluid-tight manner with an air supply passage 52 defined in a block 51 fixed in one piece to the doll 50 of the machine At this moment, during the contact

  of the air supply pipe 9 with the block 51 and when

  that the rotary body 1 is connected to the machine shaft 48 while the rod 3 is introduced axially into the shaft, the whole of the air supply pipe 9,

  of the inner sleeve 11 and the plug 12 is axially displaced

  against the spring 15, the plug 12 then being separated from the cavity 17 of the rotary body 1 and then introduced into the cavity 16 of the support shaft 7. Thus, it is seen that at the completion of the mounting of the rotary body 1 on the machine shaft 48, and subsequently, the rotating body 1 can rotate together with the machine shaft 48, but that the support shaft 7 is held in a fixed position, the plug 12 being introduced into the cavity 16

support shaft 7 -

  When the machine then receives

  In order to drive the shaft 48 in a direction to rotate the rotary body 1 which is coupled to the shaft as described above, the tool support 4 is also rotated in a direction determined by the arrow. 56 of Figure 4, that is to say in the

  same direction as the direction of rotation of the rotational body

  tif 1 If compressed air is introduced during rotation

  the rotating body 1 in the air chamber 44 through the air supply passage 52 in the block 51 and then through the air supply pipe 9, the compressed air then enters the working chamber 42 through the port 43 so as to move the drive pin 40 from the recessed position to the projecting position against the spring 41. When the drive pin is in the projecting position, one end of the pin of FIG. drive 20 away from the working chamber 42 is brought to a position enabling it to contact one of the teeth of the pinion 20 as best shown in FIG. 4, the pinion then rotating about the axis

  rotation of the rotating body 1 simultaneously with rotation

  As a result, each time the rotating body 1 is subjected to a complete rotation around

  of its longitudinal axis, the end of the spindle

  20 pinion against one of the teeth of the pinion 20 so as to rotate the externally threaded rod 18a about its own longitudinal axis If the pinion 20 comprises for example five teeth equal spacing, a

  complete revolution of the rotating body 1 causes rotation

  threaded rod 18a about its longitudinal axis at an angle of 720 in a direction determined by the

arrow 57 of Figures 1 and 4.

  By rotating the rod 18a around its own longitudinal axis, the indexing cam 21 mounted

  by screwing on the threaded rod 18a is moved axially-

  relative to the threaded shank 18 in one direction

  determined by the arrow 58 of FIGS. 1 and 4, the

  the axial displacement of the indexing cam 21 is then 0.1 naked for a rotation of 3600 of the rotary body 1 if the teeth adjacent to the threaded rod 18 a

  are spaced with a pitch of 0 D 5 mm.

  Whenever the indexing cam 21 is axially displaced relative to the threaded rod 18a, as described above, the moving wedge 24 having the inclined end face 25 slidingly engages the cam face 22 in the indexing cam 21 is moved against the spring 27 in a direction shown by the arrow 59 of FIGS. 1 and 4, that is to say in a direction away from the indexing cam 21 to the tool support 4 If the gradient of the cam face 22 is 10/1 in this specific example, the travel wedge 24 can move at a speed of 0.01 mm for a rotation of 3600 of the body As the inclined cam face 34 of the travel wedge 24 slidably contacts the flat contact face 33 of the follower pin 32, the movement of the wedge 24 in the direction shown by the arrow 59 causes the follower pin to shift.

  32 against the spring 37 in a direction

  the direction of travel of the wedge 24

  that, the tool support 4 supporting the follower pin 32 in the manner described above is moved in a radial direction relative to the rotating body 1 and in a direction shown by the arrow 60 of FIGS. 1 and 4, being guided by the dovetail protruding portion 35 in sliding contact in the dovetail groove 31 Similarly, if the gradient of the cam face 34 is 10/1 in this particular example, it is clear that the tool support 4 is moved in the radial direction at a speed of 0.001 mm for a

3600 rotation of the rotating body.

  The above description clearly shows

  that the machine tool support unit according to the embodiment of Figures 1 and 4 is provided so that when the rotary body 1 supporting the tool 54 with the bit 53 is rotated by means of the machine shaft 48 in a direction about its longitudinal axis, and

  as long as this takes place, the outer threaded rod

  18 has functionally transported through the body

  rotating 1 in the trolley section lb so as to extend

  However, as at this moment the drive pin 40 is held in the projecting position in the manner described above, the threaded rod 18 is rotated orthogonally with respect to the rotating body 1 rotates about the longitudinal axis of the rotary body 1. while rotating about the longitudinal axis of the rotating body 1, rotates about its own longitudinal axis by a predetermined angle, the driving pin 40 abutting against one of the teeth of the pinion 20 whenever the rotating body 1 has makes a rotation of 3600 The rotation of the threaded rod 18 has around

  its own longitudinal axis while continuing the rota-

  The rotation of the rotating body 1 causes stepwise feeding of the indexing cam 21 along the threaded rod 18a, which causes the displacement wedge 24 to slide axially and then the radial offset of the

  tool holder 4 against the spring 37.

  Thus, while the rotation of the rotating body 1 continues around its longitudinal axis, the wick

  cutter 53 carried by the tool holder 4 through the

  The middle of the tool 54 moves while rotating about the longitudinal axis of the rotating body 1 in a radial direction external to the axis of rotation of the rotating body 1. As described above, if the travel distance of the indexing cam 21 is 0.1 mm for a rotation of 3600 of the rotating body 1 and the displacement wedge 24 is provided to be displaced by 0.01 mm in response to the displacement of the indexing cam 21 on the distance of 0.1 mm, and if the gradient of the cam face 24 is chosen to be 10/1, the

  cutting bit 53 being turned around the longitudinal axis

  dinal rotating body 1 is moved 0.001 mm for a revolution of 3600 rotating body 1 in the outer radial direction relative to the axis of rotation of the rotating body 1 In this way, the hole formed in a workpiece ( not shown) which is supposed to be supported by a machine back doll opposite to the doll

  before the machine can be reamed accurately.

  In alternation, the cutting bit 53 supported in the manner described above may be used for milling

butt or chamfering.

  After completion of the work to be done, the rotating body 1 must be turned in the opposite direction to move the various moving parts to their initial positions. In particular, when the rotating body 1 is rotated in the direction opposite to that described above, the threaded rod 18a is rotated in a direction opposite to the direction shown by the arrow 53 so as to displace the indexing cam 21 in a direction opposite to the direction shown by the arrow 58, the displacement wedge 24 being then moved into a direction opposite to the direction shown by the arrow 59, causing a radially internal shift of the tool support 4 This can be accomplished automatically by inverting a drive motor for driving the machine spindle 48, and it is note, however, that the adjustment described above for the purpose of moving the moving parts to their positions

  initials can be executed manually as described above.

  below. When it is desired to perform the manual adjustment to bring the moving parts back to their initial positions, it is necessary to interrupt the supply of compressed air from a source of compressed air to the air supply passage 52 for allow the drive pin 40 to return to the recessed position by the action of the spring 41 and the plug 47 closing the access port 46 in the support shaft 7 must be removed Then after the rotating body 1 was turned manually until the blind axial hole 45 at the end of the threaded rod 18a near the pinion 20 was brought into alignment with the access port 46, the adjusting instrument , ie the screwdriver (not shown) must be inserted through the access port 46 by inserting its tip into the blind hole 45 The screwdriver is then rotated to bring the threaded rod 18a in the reverse direction to that shown by the arrow 57 In this way, the Moving parts of the machine tool support unit according to the present invention

  can be put back to their original positions.

  In the previous embodiment, the indexing cam 21 has been shown as a cylindrical body having the inclined cam face 22 formed externally on the cam and the moving wedge 24 has been described and illustrated as having the inclined cam face 34 formed on its outer periphery However, in the modification shown in FIG. 5, an indexing cam 62 corresponding in function to the cam

  indexing 21 is in the form of a generic block

  Rectangularly mounted screwingly on the threaded rod 18a and having two side camming portions 64 formed integrally therewith to protrude laterally outwardly in opposite directions by being inclined at a predetermined angle to the In addition, the travel wedge 24 has an end having a cavity defining two laterally spaced arms 61 surrounding the indexing cam 62, the opposing walls of the respective arms 61 having inclined cam grooves 63

  defined in such a way as to contact the

  corresponding lateral cam protruding portions 64.

  In this construction, it should be noted that the axial displacement of the indexing cam 62 along the threaded rod 18a will take place in a manner similar to that

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  described in connection with the indexing cam 21, which causes the axial displacement of the travel wedge 24, the camming side projections 64 being slidably guided in and along the inclined cam grooves 63. In addition, instead of using the inclined cam face 34 which has been described and illustrated as being formed on the traveling wedge 24 in the previous embodiment, the end of the traveling wedge 24 in the vicinity of the follower pin 32 has an inclined slot 65 for receiving the follower pin 32, this slot 65 being of a size and shape such that the axial displacement of the wedge 24 can cause the radial offset of the tool support

  4 as is the case with the previous embodiment.

  Even the system illustrated in FIG. 5 may allow the machine tool support unit to operate in the same manner as the embodiment.

  shown and described with reference to Figures 1 to 4.

  The machine tool support unit described with reference to FIGS. 1 to 5 comprises the rotary body intended to be mounted on the shaft of the machine to rotate therewith, the externally operatively threaded rod carried in the rotary body. in such a way as to extend radially with respect thereto, the tool support mounted at one end of the rotating body remote from the machine shaft for effecting movement in a radial direction relative to the rotating body, the wedge displacement member disposed within the rotary body and between the threaded rod and the tool support, the indexing cam mounted by screwing on the threaded rod and having a first cam for moving the displacement wedge in an axial direction relative to the rotating body as the threaded rod is rotated about its longitudinal axis, the displacement wedge being functionally coupled to the support

  of a tool via a second cam for converting

  firing the axial displacement of the traveling wedge in a rectilinear motion performed by the tool support in a direction perpendicular to the axis of rotation of the rotating body, and means for rotating the threaded rod intermittently at an angle predetermined around its longitudinal axis whenever the rotating body makes a complete rotation by being driven by

the shaft of the machine.

  Therefore, by appropriately selecting the number of teeth of pinion 20, the pitch of the teeth on threaded rod 18a, and / or the gradient of each cam surface employed, it is possible to allow the cutting bit 53 which then turns around the axis

  rotation of the rotating body 1 to be displaced radial-

  outwardly at a reduced speed for example

  one thousandth of the rotational speed of the rotating body.

  As a result, the bore can be advantageously

to the desired precise diameter.

  The machine tool support unit according to another preferred embodiment of the present invention is now described by specific reference

Figures 6 to 10.

  Referring now to FIGS. 6 to 10, it will be noted that the machine tool support unit according to the second preferred embodiment comprises a generally elongate rotatable block 101 connected coaxially with a rod 103 to allow for overall rotation at the same time. means of at least one pin 105 and a connecting bolt 106, the pin 105 serving to avoid any relative rotation

  possible rotary block 101 relative to the rod 103.

  A support shaft 107, generally identical in structure to the support shaft 7 of the preceding embodiment, is mounted on the rotary block 101 via two spaced bearings 108 and has a projecting lateral portion 107 formed of integrally with it in the same manner as the protruding side portion 7a of the support shaft 7, the support shaft 107 being maintained when the machine tool support unit is used in a fixed position as described in FIG. liaison with

  the previous embodiment.

  A generally cylindrical tool carrier 104 having an end for supporting the cutting bit through the carrier in a manner similar to that described in connection with the previous embodiment at its other end which has a tail groove dovetail 131 defined to extend in a radial direction, said groove 131 receiving a dovetailed protruding portion 131a which is formed on one end of the rotating body 101 away from the rod 103 of way that the tool support 104 can be guided to move in a radial direction by

relative to the rotary body 101.

  The rotary body 101 has an axial hole in which a displacement wedge 124 is axially displaceable relative to the rotary body 101. The displacement wedge 124 has a generally cylindrical configuration and has a shoulder defined at 128 as well as also an inclined cam face 134 defined to make a predetermined angle relative to its longitudinal axis This wedge 124 is normally pushed to the left as seen in Figure 6 by the action of a spring 127 disposed between shoulder 128 and a plate 130 for retaining the spring fixed to the block

  rotary 101 by means of an adjusting bolt 129.

  The tool support 104 carries a counter-key member 132 inserted into an axial hole of the tool support 104 so as to move in an axial direction relative to the tool support 104 and parallel to the axis of rotation. of the rotary block 101, the counter-key 132 defining an inclined cam face 133 slidably contacting the inclined face of

  cam 134 of the traveling corner 124 The distance on the-

  that one end of the keyway 132 in the vicinity of the displacement wedge 124 protrudes axially outwardly from the tool support 104 can be adjusted by turning an adjustment bolt 166 threadedly carried by the tool support 104, one end thereof abutting against the other end of the keyway 132 away from the wedge 124 To prevent any separation of the key-132 against the axial hole of the tool holder 104, the counter-key 132 is maintained in position by a retaining bolt 167 adjustably supported by the tool support 104 so as to extend radially relative to the tool support 104, one of

  its ends contacting a flat inclined axial face-

  168 which is defined in the counter-key 132 at a location axially rearward with respect to the inclined cam face 133 To avoid any loosening of the retaining bolt 167, a locking bolt 169 is used which is inserted in the same hole as the holding bolt 167, which maintains the latter in

position.

  A pusher 138 corresponding to its function

  at the pusher 38 used in the above embodiment.

  dente is carried by the rotary block 101 so as to move in a radial direction relative to the rotary block 101 by means of a support boss 136, one end of which has a hole receiving the pusher 138, the support boss 136 being screwed by being held in position within a defined hole in the rotary block 101 The pusher 138 supported in the manner described above is normally urged by a coil spring 137 mounted around the pusher so that one end thereof The last one remote from the support boss 136 is kept in constant contact with the cross-key 132. Reference numeral 170 is a rubber dust-resistant elastic cover sleeve which is mounted to encircle the seal. finding between the block

  rotary 101 and the tool support 104.

  The indexing mechanism to move axially

  Then, the travel wedge 124 in response to each complete rotation of the rotatable block 101 driven by the machine shaft with the rod 103 includes a movable control member 118 having an externally threaded shaft 118a, an indexing cam 121 threadably mounted on the threaded rod 118a and a pinion or spider 120 rigidly mounted on one end of the threaded rod 118a so as to rotate together An automatically release clutch assembly 183 is interposed between the pinion 120 and the threaded rod 118a so that when there is possibly an overload, the connection between the threaded rod 118a and the pinion 120 can be automatically eliminated to prevent any damage to the indexing mechanism The pinion 120 just as in the embodiment previous, can contact a control pin 140 each time the rotating body 101 has made a complete rotation, the control pin etan is supported by the support shaft 107 to effect a movement between projecting and receding positions in a radial direction with respect to the rotatable block 101. The threaded shaft 118a is rotatably supported but so as not to be able to rotate. move axially within a radial hole of the rotary block 101 by means of two spaced bearings 119

  to extend in a radial direction relative to the rotational block

  The indexing cam 121 mounted on the threaded shank 118a has an inclined cam face 122 which it defines to slidably contact the inclined end face 125 of the travel wedge 124, while also having a Keyway 123 defined in an inclined cam face 122 and in which a corresponding key is slidably inserted.

  126 protruding axially outwardly of the end face

  inclined mite 125 of the travel wedge 124.

  As is the case with the control pin used in the previous embodiment, with reference to FIGS. 1 to 5, the control pin 120 is moved from the recessed position to the position

  protruding against a thrust spring 141 when

  that a pressure is introduced into the working chamber 142, in the same manner as in the previous embodiment when the control pin 140 is in the projecting position, one end of the control pin 140 remote from the the working chamber 142 is held in position so as to be able to contact any one of the teeth of the pinion 120, so that each time the rotary block 101 has made a complete rotation while being driven by the shaft of the machine, the threaded rod 118a can be rotated about its own longitudinal axis to move the indexing cam

  121 along the threaded rod 118 a.

  Between the outer peripheral surface 172 of the travel wedge 124 and the wall 171 defining the axial hole of the rotary block 101 in which the travel wedge 124 is movably received, a plurality of miniature balls 173 are interposed to facilitate and obtain a In the same way, several juxtaposed rollers 174 of small diameter are interposed between the inclined cam face 133 of the counter-key 132 and the

  corresponding inclined cam face 164 of the displacement wedge

  124 as shown best in FIGS. 8 to 10, the balls 173 are retained by a generally tubular retaining device 175 in two groups, the device of FIG. retained with the balls 173 that it supports being disposed within the axial hole of the rotary block 101 and outside the wedge 124 The retaining element is made of a metal whose thickness is smaller than the diameter of each of the balls 173 and has two orifices 176a and 176b making it possible to receive the

  respective groups of balls 173, as it is clear

in Figure 10.

  It should be noted that the inclined cam faces

  133 and 134 of the counter-key 132 and the corner of

  124, respectively, may comprise, as clearly shown in Figure 11, associated shoulders defined at 178 and 177 and spaced apart from each other so that the juxtaposed rollers 174 may be wedged between the inclined cam faces 133 and 134 without possibility of separation from an intermediate space Alternatively, or in combination with the system shown in FIG. 11, the juxtaposed rollers 174 may be retained by a generally rectangular retaining element 179, as shown in FIG. rollers 174 in a position lying between the inclined faces of

133 and 134.

  In addition, although the tubular retainer shown in Fig. 10 has been described as having ports 176a and 176b for receiving groups

  respective balls 173, it may comprise several

  drillings 180 defined in this element 175, in place of the orifices 176a and 176b so as to receive the balls

  173, as shown in FIG. 13.

  We see from the previous description of

  the embodiment of Figures 6 to 13 that the machine tool holder unit operates in a manner

  closely similar to that according to the first form of

  preferred embodiment of the present invention, as illustrated and described with reference to FIGS.

  particular, during the continuation of the rotation movement

  rotating the rotary body 101 in one direction, and if the control pin 140 is in the helical position, the threaded rod 118 is rotated by a predetermined angle by the contact of the control pin 140 with one of the teeth of the pinion gear 120 integral with the threaded rod 118 each time the rotary block 101 makes a complete rotation When the threaded rod 118a is rotated about its longitudinal axis in this manner while rotating about the longitudinal axis of the rotary block 101 the indexing cam 121 is moved axially relative to

  to the threaded rod 118a, which pushes the wedge of

  124 The axial movement of the travel wedge 124 thus effected is transmitted to the tool support 104 by the counter-key 132 so as to displace the spring 127 in a direction away from the threaded rod 118a. tool support 104 against the spring 138 in a radial direction relative to the

rotary block 101.

  The inverse rotation of the machine shaft and consequently of the rotary block 101 causes the return of the

  various moving parts to their initial positions.

  In particular, the embodiment shown and described with reference to FIGS. 6 to 13 is advantageous in that the axial displacement of the wedge 124 and the relative sliding between the travel wedge 124 and the counter-key 132 take place approximately without friction because of the use of bearings such as balls

  173 and the rollers 174, as fully described above.

  Thus, the resistance that would act on the movement of the travel wedge 124 is advantageously reduced and therefore the load that can be imposed on the indexing mechanism can also be reduced, which has the consequence that the tool support can be moved. smoothly in the radial direction with respect to the block

rotary 101.

  The principle of using the roller bearings can also be applied to the joining part located between the rotary block 101 and the tool support 104. In accordance with this teaching, as shown in FIG. a plurality of roller bearings each having a retaining portion 181 and a plurality of juxtaposed rollers 182 retained in position by the respective retaining member 181 between the wall surface defining the dovetail groove 131 and the wall surface of the portion protruding dovetail 131A solid rotary block

  101, which reduces the resistance that would act on the

  In the modified form shown in FIG. 14, instead of using the juxtaposed rollers 182 retained by the respective retaining elements 181, roller bearings are used, each of which is supported on the rotational block 101. comprises a perforated retaining plate 281, the perforations of which receive the respective balls 283, between the tool support designated by the reference numeral 204 and the rotary block 101 designated by the reference numeral 201, the dovetail groove tool support 204 and the integral dovetail projecting part with the rotary block 201 being respectively designated by the

reference 231 and 231 a.

  In the alternative embodiment of Figure 15, the tool holder 304 is radially movably connected to the rotatable block designated by the reference numeral 301, by means of a groove 331 of generally shaped cross section. of T, defined in the tool holder 304, and a correspondingly projecting T-piece protruding portion 331 in one piece with the rotary block 301, with a plurality of roller bearings

  functionally interposed between them. The modified form

  Fig. 16 is similar to that shown in Fig. 15 with the difference that while the roller bearings used in the modified embodiment in Fig. 15 each comprise a retainer 381 carrying a plurality of side-by-side rollers 382, the roller bearings used in the modification of FIG. 16 each comprise a retaining piece 381a in which are formed several perforations receiving

  a corresponding number of beads 383.

  Although the present invention has been fully described in connection with the many embodiments and with reference to the accompanying drawings, it is

  note that various modifications and variations

  experts of this technique Such modifications and changes are included in

the scope of the present invention.

Claims (13)

  1 Machine tool support unit   changeable device intended for a machining apparatus for supporting a machining element, characterized in that it comprises a generally elongate rotary body (1), one end of which is intended to be connected to a rotating control source (48), a tool support (4) carried by the rotary body (1) so as to move in a radial direction relative to the rotary body   supporting a machining element (53) at one of its ends.   opposed to the rotary body (1), an axially displaceable element (24) borne so as to be able to move axially inside the rotary body (1), a cam   (21) for transmitting the axial displacement of the element   movably (24) to the tool support (4) to move the latter in a radial direction relative to the rotary body (1), and an indexing mechanism (18) for intermittently displacing the displaceable member (24). ) in the axial direction of the rotating body each time the latter has performed a complete rotation while being   driven by the control source (48).   2 Tool support unit according to the claim   1, characterized in that the indexing mechanism   (18) comprises an externally threaded rod (18 a) supporting   functionally within the rotating body (1) so as to extend in a radial direction relative to the rotating body, a toothed pinion (20) mounted on one end of the threaded rod (18 a) so as to execute a rotational movement with it, and an indexing cam (21) mounted on the threaded shank (18a) so as to be movable in an axial direction relative to the threaded shank, the indexing cam being movable axially along the threaded rod so that the latter is turned about its longitudinal axis, the displaceable element (24) being displaced axially in response to the axial movement of the indexing cam (21).   3 Tool support unit according to claim   cation 1, characterized in that the toothed pinion (20) is connected to the threaded rod (18 a) via a load-responsive and automatically disconnectable clutch operating to separate the pinion   toothed (20) of the threaded rod (18 a) during an overload.   4 Tool support unit according to any one   one of claims 1 to 3, characterized in that   comprises a support shaft (7) mounted on the rotary body (1b), the support shaft (7) comprising a control transmission element for rotating the threaded rod (18a) by a predetermined angle about its longitudinal axis whenever the rotating body (1) makes a complete rotation.   5 Tool support unit according to the claim   4, characterized in that the control transmission element comprises a control device controlling the transmission of the rotary motion of the rotary body. towards the threaded rod (18 a).   6 Tool support unit according to the claim   4, characterized in that the control transmission element comprises a drive pin (40) carried by the support shaft (7) so as to contact one of the teeth of the toothed gear (20), the shaft threaded (18 a) being rotated each time the drive spindle   (40) abuts against one of the sprocket teeth (20).   7 Tool support unit according to claim   cation 6, characterized in that the control device comprises a thrust spring (41) bringing the control pin (40) to a recessed position where it is away from the rotational path of the pinion (20). , and an air supply device (44) for moving the control pin (40) against the push spring (41) to a projecting position where the control pin is ready to contact 'a   any of the teeth of the toothed gear (20).   8 Tool support unit according to claim   cation 1, characterized in that the cam (21) comprises a follower element (32) rigidly fixed to the support of tool (4) -   9 Tool support unit according to the claim   1, characterized in that the cam (121) comprises a countercombette (132) adjustably supported by the tool support (104) for adjustment in an axial direction relative to the rotational body and in a direction towards the displaceable element (124) and away from it.   10 Tool support unit according to the claim   1, characterized in that it comprises first   roller bearings (173) interposed between the circumferential surface   of the displaceable element (124) and the wall defined   a hole in the rotatable body (104) for receiving the displaceable member, and a second roller bearing interposed between a defined cam face (134).   in the displaceable element (124) and a corresponding cam face   (133) defined in a cam element (132)   forming a portion of the cam (121) and carried by the tool support (104) to facilitate and obtain relative sliding movement between the movable member (124) and the cam member (121).   11 Tool support unit according to the claim   1, characterized in that one end of the tool support (204) adjacent the rotary body (201) has a connecting groove (231) defined to extend in its radial direction, and one end of the rotating body in the vicinity of the tool support (204) has a corresponding projecting portion (231a) formed therein so as to extend in its radial direction, said projecting portion being slidably received in the groove of connecting together the tool support (204) and the rotating body (201), a third roller bearing (283) being interposed between the corresponding projecting portion (231a) and the groove connection (231).   12 Tool support unit according to the claim   11, characterized in that the groove (231) is a dovetail groove and that the corresponding projecting portion (231a) is a dovetail portion having a cross-sectional configuration which is complementary of that of the dovetail groove.   13 Tool support unit according to the claim   11, characterized in that the groove (331) has a generally T-shaped cross section and that the corresponding protruding portion (331 a) has a cross-sectional shape complementary to that of the groove.