Abstract:
A boring head, essentially consists of a body ( 1 ) provided with a housing ( 2 ) for receiving two tool-holders ( 3 ), capable of being radially driven via a moving device ( 4 ), and of element ( 5 ) for locking the tool-holders ( 3 ) in operational position. The boring head is characterized in that the element ( 5 ) locking the tool-holders ( 3 ) in operational position consists of a single clamping device simultaneously acting on the two tool-holders ( 3 ) and on the body ( 1 ). The invention is more particularly applicable in the field of machine-tool accessories, in particular digitally controlled machines, of machining plants and adaptable cells and workshops.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to the field of machine tool accessories, in particular digitally controlled machines, machining centers and adaptable units and workshops and has for its object a boring head adapted to enlarge holes having very rigorous geometric characteristics, by means of a range of bit carriers of the interchangeable slide type. 
   There exist at present different devices permitting adjusting the selected diameter. However, in these devices, the locking of the assembly elements cannot be carried out by a single gripping means and generally requires several gripping means. Moreover, in devices provided with two bit carriers or slides, the adjustment cannot be carried out as desired from either side and it is impossible to carry out a simultaneous or independent adjustment of the two slides. 
   SUMMARY OF THE INVENTION 
   The present invention has for its object to overcome these drawbacks by providing a boring head permitting centralized blocking of the bit carriers or slides and individual or simultaneous adjustment of said slides. 
   For reasons of simplicity and clarity of the description, the bit carriers will be called slides. To this end, the boring head, which is constituted by a body provided with a recess for the reception of two slides, that can be driven radially by means of a movement device, and by means for locking in service position the slides, is characterized in that the means for locking in service position of the slides is constituted by a single gripping device acting simultaneously on the slides and on the body. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood from the following description, which relates to a preferred embodiment, given by way of non-limiting example, and explained with reference to the accompanying schematic drawings, in which: 
       FIG. 1  is a side elevational and partial cross-sectional view of a boring head according to the invention; 
       FIG. 2  is a side elevational view of the boring head of  FIG. 1 , turned 90° about its longitudinal axis, the slides being removed; 
       FIG. 3  is a view analogous to that of  FIG. 2 , partially in cross-section, the slides being mounted; 
       FIG. 4  is a cross-sectional view on the line A—A of  FIG. 2 ; 
       FIG. 5  is a plan view of a slide, and 
       FIG. 6  is a perspective view of the single locking means. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1-3  of the accompanying drawings show, by way of example, a boring head, which is essentially constituted by a body  1  provided with a recess  2  for the reception of two slides  3 , that can be driven radially by means of a movement device  4 , and by a means  5  for blocking the slides  3  in service position. 
   According to the invention, the means  5  for blocking the slides  3  in service position is constituted by a single gripping device acting simultaneously on the two slides  3  and on the body  1 . 
   The recess  2  for reception of the slides  3  is present, in known manner, in the form of a prismatic notch extending perpendicularly to the longitudinal axis of the body  1  in the front end of this latter. 
   The slides  3  are in the form of bit carriers that are identical or of different heights and are each provided with a machining bit connected by screwing or by raising. The use of slides of different height permits, in the case of machining with the removal of a large thickness of cuttings, an offset of the bit effecting the smallest diameter in front of the bit effecting the larger diameter. These slides  3  are each provided, on the side penetrating to the bottom of the recess  2 , a drive groove  6  adapted to coact with the movement device  4  and extending perpendicular to the direction of movement of the slides  3 . 
   According to one characteristic of the invention, the movement device  4  is preferably constituted by a pair of lugs  7  which, on the one hand, each penetrate by their ends into a corresponding drive groove  6  of a slide  3  and, on the other hand, coact, at their other end, with an adjustment screw  8  and with a coupling means  9  for actuating the adjustment screw  8 . Thus, by placing in rotation the adjustment screw  8 , the latter produces a movement of the corresponding lug  7  and, because of this, a radial displacement of the slide  3 . 
   The adjustment screws  8  are preferably disposed head to tail parallel to the bottom of the recess  2  of the body  1 . 
   The means  9  for coupling the actuation of the adjustment screws  8  is preferably constituted by a pair of pinions  10  mounted respectively one near the head  8 ′ of one of the screws, and the other near the free end of the other screw  8 . Preferably, the pinion  10  mounted near the free end of one of the screws  8  is fixed on this latter by means of an expansible device constituted by a gripping screw  11  with a truncated conical head and by the slotted end  8 ″ of the screw  8 . The provision of such an expansible device permits, on the one hand, by gripping the screw  11  with a truncated conical head, a blocking in position of the pinion  10  on the end  8 ″ of the screw  8 , following the expansion of said end  8 ″ and, on the other hand, the possibility of a sliding mounting of the pinion  10  on the end  8 ″, by partially unlocking the screw  11  with a truncated head. In the first case, the actuation of one of the screws  8  could have the result of synchronous driving of the other screw  8  and hence a simultaneous movement of the two slides  3 , whilst in the second case, each slide  3  could be moved independently by actuation of the corresponding adjustment screw  8 , the pinion  10  mounted on the end  8 ″ of one of the screws being thus in free rotation on this end. This pinion  10  could then undergo a drive having no effect on the screw  8  on which it is mounted or statically resting when the screw on which it is mounted is actuated. 
   The actuation of the screw with a truncated conical head  11  can be carried out through a hole  11 ′ in the body  1  aligned with the axis of the corresponding screw  8 . 
   The heads of the screws  8 ′ of the adjustment screws  8  are each provided with a positioning and holding means in translation, in the form of a lateral abutment without play, constituted by an assembly of throats  12  and  13  provided respectively in the screw head  8 ′ and in the body  1  and by balls  14 . The mounting of the balls  14  in such a lateral abutment is carried out in known manner by means of a radial or tangential hole  15  ( FIG. 2 ) provided in a screw-threaded plug  16 . Such a mounting permits positioning and holding of the screws  8  without play, with the possibility of adjusting the hardness of operation by more or less pronounced gripping of the screw-threaded plug  16 . 
   In a known manner, the screw heads  8 ′ of the locking screws  8  are provided, on the one hand, with means for operating by a key  17  and, on the other hand, a scale  18 . There is thus the possibility of verifying immediately the quantity of movement of the corresponding slides  3  carried out during actuation of the screw  8 . 
   Moreover, the two screws  8  being identical, and a synchronous drive of them being possible, the movement device  4  is a bilateral actuating device, which further facilitates the adjustment movements. 
   The screws  8  coact with slides  3  by means of lugs  7 , the recesses of the screws  8  and pinions  10  which they are provided with are connected to the recess  2  of the body  1  by means of a through recess  19 . As a result, impurities or waste from machining can if desired pass through the recess  19  into the recesses of the screws  8 . To avoid penetration of such impurities or waste between the teeth of the pinions  10 , the corresponding portions of said recesses are closed by means of a plate  20  connected against the corresponding surface of the pinion  10  mounted at the free end of one of the screws  8 . 
   As will be seen more particularly from  FIG. 4  of the accompanying drawings, the mounting of the plate  20  can for example be carried out against the pinion  10  mounted at the free end of the screw  8 , by arrangement of said plate  20  between a shoulder of the screw  8  and said pinion  10 . Such a mounting of the plate does not require further description and is well within the scope of those skilled in the art. 
   The single locking device acting simultaneously on the two slides  3  and on the body  1 , forming the means  5  for blocking in service position of said slides  3 , which is shown more particularly in  FIGS. 1  to  3  and  6  of the accompanying drawings, is constituted by a screw  21  passing perpendicularly through the recess  2  and the slides  3  and provided with a head  21 ′ with a conical periphery coacting with counterbore  22  on one of the portions of the body  1  delimiting the recess  2 , by a locking ring  23  bearing below the head  21 ′ of the screw  21  and coacting with its opposite end with one of the slides  3 , and by a nut  24  with a conical periphery coacting, on the one hand, with a counterbore  25  on the other of the portions of the body  1  delimiting the recess  2  and, on the other hand, at its end opposite to the counterbore  25  with the other slide  3 . 
   According to one characteristic of the invention, the locking ring  23  is mounted freely in rotation on the screw  21  and is provided with two diametrically opposed flats  23 ′ adapted to coact with surfaces  26 ′ of a passage hole  26  of oblong cross-section, whose length slightly exceeds the diameter of the ring  23 . 
   Moreover, according to another characteristic of the invention, the locking ring  23  is provided, at its end opposite to the screw head  21 ′, with two inclined flats  27  offset by 90° relative to the flats  23 ′ and coacting with chamfers  28  of the same inclination provided on the corresponding surface of the corresponding slide  3  at the periphery of an oblong hole  29  for passage of the screw  21 . 
   The nut  24  is provided with a conical periphery  24 ′ coacting with the bottom of the counterbore  25  and comprises, below said conical periphery  24 ′, diametrically opposed flats  30  adapted to coact with surfaces  31 ′ of a passage hole  31  of oblong cross-section, whose length slightly exceeds the diameter of the nut  24  below the conical periphery  24 ′. 
   Moreover, the nut  24  is provided, at its end opposite the conical periphery  24 ′, with two inclined flats  32  offset 90° relative to the flats  30  and coacting with chamfers  28  of the same inclination provided on the corresponding surface of the corresponding slide  3  at the periphery of an oblong hole  29  for passage of the screw  21 . 
   The oblong hole  29  of the slides  3  has a width greater than the diameter of the screw  21 , so as to permit clearance of the slides  3  relative to the screw  21 , along the longitudinal axis of the body  1 . 
   By locking the nut  24  on the screw  21  by means of a coacting tool, for example with the head  21 ′ of the screw  21 , the nut  24  and the locking ring  22  are pressed into the chamfers  28  provided at the periphery of the oblong holes  29  of the slide  3  and lock these latter one against the other by their adjacent surfaces. In this same movement together of the nut  24  and the ring  22 , the coaction of the inclined flats  27  and  32  of the ring  22  and the nut  24  with one of the chamfers  28  on a same side of the oblong holes  29 , has the effect of giving rise to simultaneous movement of the slides  3  tending to press them, on the one hand, against the forward surface of the body  1 , and, on the other hand, preferably against the bottom of the recess  2 . As a result, the slides  3  are perfectly locked in service position and held against any risk of pivoting on the body  1  by application of the corresponding surfaces. 
   According to another characteristic of the invention, the counterbores  22  and  25  for receiving the head of the screw  21 ′ and the nut  24 , have an outwardly curved bottom chamfer adapted to coact with the corresponding conical peripheries of the head of the screw  21 ′ and  24 ′ of the nut  24 . 
   The provision of contact surfaces with a conical periphery between the screw head  21 ′ and the counterbore  22 , as well as between the nut  24  and the counterbore  25 , permits guaranteeing an optimum application of the locking force for the locking of the slides  3 , whilst ensuring a degree of freedom in the case of slight misalignment between the axes of the oblong holes  29  of the slides  3 . Moreover, the construction itself of the single locking device acting simultaneously on the two slides  3  and on the body  1 , forming the means  5  for blocking in service position said slides  3  and that of the counterbores  22  and  25  permit as desired the mounting of this means  5  from one or the other side of the front portion of the body  1 . 
   According to another characteristic of the invention, and as shown more particularly in  FIG. 1  to  3  of the accompanying drawings, the body  1  is provided moreover with a central lubricating device constituted by channels  33  bored in said body  1  and opening at the front end of this latter, near the cutting bits  3 ′ of the slides  3 , these said channels  33  being connected, at the rear end of the body  1 , to a central supply channel  34 . 
   Thus, it is possible to bring cutting lubricant to the immediate vicinity of the cutting tools, without having any contact between said lubricant and the mechanical members for adjusting and blocking the boring head. 
   Thanks to the invention, it is possible to provide a boring head permitting the use of identical slides or of different sizes for offset working and guaranteeing an adjustment and particularly precise and reliable blocking of said slides. Moreover, because of the provision of simultaneous bilateral adjustment and blocking by means of a single device, the use of such a boring head is particularly simple and rapid and the corresponding costs are accordingly reduced. 
   Of course, the invention is not limited to the embodiment described and shown in the accompanying drawings. Modifications remain possible, particularly as to the construction of the various elements or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.