TOOL HOLDER FOR CLAMPING INSERTS, USING A RESILIENT L-SHAPED CLAMP

Abstract: Tool holder device having an elongated main body presenting a rearwardly extending back portion (2) to be received inside a turret body groove and locked therein by means of wedge means, a forwardly extending portion having an obliquely arranged abutment surface (3) and an outwardly facing surface (5) defining the position of the insert tool holder. The adjoining surface (6) of the main body having an elongated groove (7) having parallel walls also in parallel with the outwardly facing surface and a bottom perpendicular to same surface and in an intermediary position a number of threaded bores (8) extending essentially in parallel with the outwardly facing, a seat for the tool holder defining surface (5). The groove being adapted to receive two or more L-shaped clamping pieces (9) having one leg (10) with an end portion with a thickness corresponding to the width of the main body elongated groove (7) and another leg (11) having an abutment seat (12) for the tool holder and through bores (13) for screws essentially in parallel with the former leg and with an adjoining abutment surface for the screw head, the clamping piece adjacent joining of its two legs having a mutual bending facilitating recess or groove (16).

Description: Tool holder for clamping inserts, using a resilient L-shaped clamp. Technical field of the invention This invention relates to a so called tool holder or clamping piece for insert holders for turret tool holders and the like . Here the tool holder is clamped in a seat at the turret and the insert holder in the tool holder . Prior art A known clamping piece or tool holder is divided in a base part having abutments for clamping wedges and screws for securing the base part in grooves at the turret body and a carrier piece for the tool or insert holder which later piece as also the base piece has complementary guiding and positioning portions, on securing the pieces to each other engaging each other and localizing the parts as well as at the carrier piece arranged setable and adjustable guides for clamping bodies pressing the tool holder towards an abutment. Another known embodiment includes a tool holder made in one piece with a rear protruding portion intended to be wedged inside the turret body groove and having an elongated clamping rail intended to secure the tool holder by means of screws passing through holes in the rail and inserted into the holder body, an opposite edge of the holder abutting a seat at the holder proper. DE, Al 3434 089 and GB, B 19851/1909 disclose arrangements for securing parting tool holders and tools by means of an essentially L-shaped clamping piece one leg of which rests in an elongated groove at the base part whereas the other leg engages a tool holder or tool in order to press same against a seat when prsεed towards the base part by means of one or more screws. The former publication also reveals a weakening slot made in the leg of the clamping piece engaging the elongated groove to facilitate the movement of the other leg towards the tool holder. The later publication discloses a rigid L-shaped clamping piece, on setting the screw swinging the clamping piece around an axis at the line of engagement along the base part groove. The correspond ng axis of the weakened leg clamping piece follows the bottom of the said weakening groove. The positioning of the said axes below a plane perpendicular to the plane of the tool holder and passing the point or line of engagement at the free edge of the tool holder implies that any force excerted towards the tool holder engaging leg of the clamping piece, will result in a division of the force acting against the tool holder edge in one component acting in the plane of the tool holder and one component pushing outwardly so as to remove the holder from its seat. DE, B2 2 548 870 and US, A 4 545 705 disclose arrangements similar to the one shown in GB, B 19851, i.e. clamping pieces having one leg resting in a groove and the other leg engaging a tool holder or tool. In all cases the clamping piece swings around an axis situated well below a plane through the upper edge of the tool or tool holder. Aspects of the invention One aspect of this invention is to bring about a new tool holder having a simple construction and easily manufactured without complicated machining and the like. Another aspect is to fulfill a since long felt need of facilitating the change of tool holders without necessitating dismantling of a multitude of pieces. Still another aspect is to make a new tool holder device so arranged as to secure as stable as possible a clamping of the tool holder by arranging the contact directions of the clamping piece. Summary of the invention The tool holder according to this invention includes an elongated main part having a number of longitudinal grooves, ridges and surfaces designed to form both a rearwardly extending back portion insertable into the turret body recess and securable therein by means of known wedging means, one forwardly protruding portion having an obliquely localized abutment surface together with a joining outwardly facing surface forms to position for the insert holder defining parts, wherein the opposite edge of the outward] facing surface is joined with a backwardly obliquely arranged surface in turn passing into an elongated groove having paralle] walls also parallel with said outwardly facing surface and a bottom at right angles with said surface. The portion having the rearwardly obliquely arranged surface, presents a number of threaded bores which are essentially parallel with the surface defining the outwardly facing site for the insert holder. At the main part there are mountable two or more essentially L-shaped clamping pieces having a non significant length dimension and having one leg with one end portion having a thickness closely corresponding to the width of the elongated groove at the main part and one leg having an oblique inner abutment face and at least one through hole essentially parallel with the formal leg and having an adjoining abutment surface for the head of a screw which surface s obliquely arranged so that a screw passed through the bore and into a threaded bore at the main part will engage essentially only at the portion of the abutment surface closest to the leg end having the obliquely arranged surface. The clamping pieces have at the point where the two legs are joined a recess facilitating the bending of the material. Brief description of the drawings One preferred embodiment of the device according to this invention will be described more in detail in the following with references to the accompanying drawings, in which Figure 1 is a side view of the tool holder main part seen from the outside, Figure 2 is an end view of the same part from one end, Figure 3 is a front end view on a larger scale of a clamping piece, Figure 4 is a side view of the same, and Figure 5 is an end view on the same scale as Figures 1 and 2 of the clamping piece mounted on the main part and with an nsert holder. The main part, i.e. the tool holder 1, is formed by a piece of steel by milling or the like machining given a specific shape. At part 1 there is at the rear end, i.e. on the side which in mounted position will be facing the turret body, an elongated extending portion 2, which forms a specific portion to be inserted into a groove at the turret body and secured therein by means of known, not shown wedging means inserted between the extending portion and the opposite wall of the groove. The front side of part 1 shows at the lower portion thereof an elongated projection 3 having a dov/nwardly and inwardly inclined upper edge 4 serving as an abutment for an insert holder placed thereon. A front face 5 adjoins to this abutment and defines together with it two sides of the seat for the insert holder. The front face 5 changes over into a rearwardly and downwardly inclined surface 6 which inclines towards a groove 7 arranged in the upwardly facing side of the part, said groove having sides parallel with the front face 5 and bottom essentially at right angles with the sides. The main part also includes at least two threaded bores 8 extending essentially parallel with the front side 5 from the inclined surface 6. To each main part are attached at least two clamping pieces designated 9. Each clamping piece includes an inverted essentially L-shaped piece of material having insign * > ficant length and preferrably manufactured by machining rod material into desired sectional shape and subsequent cutting in needed lengthes . Each clamping piece has a downwardly directed leg 10 having a thickness A closely corresponding with the width B at the longitudinal groove 7. The engagement between said leg and the groove ensures a secure localization of the clamping piece. The other leg 11 has at the underside of the outer end an obliquely arranged surface 12 which serves as contact surface towards the insert holder edge and also presents a bore 13 essentially parallel with the former leg 10. The bore is connected to a counter sunk seat or abutment portion 14 for the head of a screw which is threaded through the bore 12 into any one of the threaded bores 8 of the main part and this counter sunk seat is obliquely arranged so that the portion 14a thereof adjacent the outer end of the leg is higher and consequently will meet the head of the screw first and serve as abutment for the same. At the transition 15 between the two legs there is an obliquely arranged recess or slot 16 which gives to two legs a mutual mobility. After securing the main part 1 of the tool holder in a per se known way at the turret body groove, the insert holder S will be mounted and this takes place by placing the insert holder with the lower side thereof towards the lower obliquely arranged edge 4 and engaging the front surface 5. The clamping pieces 9 are secured in desired positions aligned with the bores 8 by inserting the rear leg 10 into the groove 7 and threading the screws 8 into the bores. As soon as a screw head reaches the front portion 14a of the counter sunk seat 14, the upper leg will swing over the transition 15 between the two legs whereby the obliquely arranged surface 12 will contact the insert holder s and press the same downwardly towards the opposite abutment 4 and simultaneously inwardly towards the surface 5. The more the screw is tenεioned, the leg 11 will swing more downwardly and to allow this the bore 13 for the screw is so shaped that the screw shaft will run freely therethrough even if the leg is swung out of its original position. By arranging a recess 16 the transition 15 between the two legs 10 and 11 there iε achieved a hinge function. The pivot axis thereof will be situated at a rather high level and this results in an efficient press action towards the insert holder. This is the result of the lever relations existing where the fulcrum of the one armed lever, i.e. the transition portion 15, will be situated higher than a normal plane perpendicular to the upper edge of the insert holder and the contact surface at the end of the leg. The fork resulting from the tenεioning of the screw and acting at the contact point between the end of the leg 11 and the insert holder may be divided in one component parallel with the plane of the insert holder and the front face 5 and one inwardly directed component perpendicular thereto. Consequently on tightening the screws the insert holder will be pressed downwardly towards the opposite abutment 4 and simultaneously against the front side 5 of the main part 1. The invention is not restricted to the above described embodiment but may be modified within the scope of the attached claims.

Claims: C L A I M S 1. Tool holder device for tool holders and the like for receiving insert holders and similar devices at tool carrying means such as turret bodies, wherein the tool holder has a seat for an insert holder including one rigid abutment for one edge of the insert holder, one lateral abutment and one or more clamping pieces intended to engage an opposite edge of the insert holder, wherein at the main part (1) of the tool holder remote from the seat is arranged an elongated groove (7), and along said groove between the same and the seat bores (8) for setting screws and wherein clamping pieces (9) are essentially L-shaped having one leg (10) intended to be received in the longitudinal groove (7) and one leg (11) having a bore and a free end presenting a contact surface for the edge of the insert holder, c h a r a c t e r i z e d in that the elongated groove (7) and the leg (10) of the clamping piece (9) intended to engage the same groove are mutually adjusted so that the leg is essentially rigidly received in that groove, that at the transition (15) between the two legs (10,11) is arranged a per se known slot or recess (16) enhancing the mutual bendability of the legs, that the bore for the set screw at the one leg has a surrounding counter sunk seat intended to form an abutment for heads arranged at such screws and that such seats are unsymmetrical in order to allow concentration of the press force to the portion thereof adjacent the contact surface leg end, and that the leg (10) engaging the groove (7), the contact surface at the end of the opposite leg, the engagement point of the screw head at the bore seat and the position of the bending enhancing slot (16) are so mutually localized and adapted that on tightening the screw the free leg (11) in turn engages the insert holder edge with a force acting both along the plane of the insert holder towards the opposite abutment (4) and inwardly towards the front side of the tool holder. 2. Arrangement according to claim 1, c h a r a c t e r i z e d in that the seat (14) enclosing the bore (13) of the free leg (11) is obliquely arranged relatively to the center axis of the bore and that the portion (14a) thereof adjacent the free end of said leg is higher than the rest and intended to engage the head of a screw threaded into the tool holder body. 3. Arrangement according to claims 1 or 2, c h a r a c t e r i z e d in that the portion of the free leg (11) contacting or engaging the edge of the insert holder (S) is obliquely arranged (12).

Inventors: MIHIC WLAJKO, MIHIC, WLAJKO
Applicants: MIRCONA AB
Application year: 1992
Main classification: B23B29
IPC codes: B23B27, B23B29