FR2581572A3 - DEVICE FOR BLOCKING TOOL HEADS ON A MACHINE-TOOL TOOL HOLDER - Google Patents

Abstract

The invention relates to a device for locking at least one tool head 2 on a tool holder 1 by means of a traction element 5. The problem to be solved consists in obtaining a simple assembly without play. The device is characterized. in that the tool head 2 is provided for centering with a conical side surface 2b cooperating with a corresponding conical side surface 1b of the tool holder 1, flat faces 1a, 2a formed at the large diameter end of the Conical surfaces 1b, 2b of the tool holder and of the tool head determining the axial position under the axial force of the traction element 5. The invention is applicable to machine tools. (CF DRAWING IN BOPI)

Description

DEVICE FOR BLOCKING TOOL HEADS ON A DOOR

TOOLS OF MACHINE TOOL.

  The invention relates to a device for locking tool heads provided with at least one cutting edge for machining by chip removal, on a carrier

  machine tool tools that do not rotate during machining

  with centering surfaces formed on the tool head and the tool holder and with abutment faces for determining the axial position, an axially displaceable pulling element being provided for fixing the tool head on the tool holder, the tool head being guaranteed against rotation relative to

  to the tool holder by a key and groove connection.

  Such devices for locking tool heads on a machine tool holder are known according to

different achievements.

  In one of these known embodiments, a cylindrical centering element is formed on the tool holder, the tool head made with a cylindrical bore

  being engaged on this centering element. The head of ou-

  it is guaranteed against rotation by a tongue disposed on the tool holder in the radial direction and which engages in a corresponding radial groove of the tool head. The locking of the tool head on the tool holder is ensured by a plurality of clamping pins inclined with respect to the radial direction

  and which engage in an annular groove of the bore

  age of reception of the tool head. When actuated by the traction element provided with a conical head, these clamping pins act so that the

  tool head is pushed against a flat face of the holder

  tools. This known embodiment has the disadvantage that there is necessarily a game because of the realization

  cylinder of the engagement element formed on the carrier

258157,

  tools. This game can not be eliminated because of the

  because it requires a difference in diameter between the

  Cylindrical engagement piece and the tool head receiving bore for setting and removing this tool head. Since this game must be

  kept at a low value for reasons of stability

  There is only a small amount of centering

  that the known realization does not permit the automatic change

  of the tool head only if the apparatus of change

  automatic operation works with a very high degree

  if we. Another decisive disadvantage arises from the fact that the force transmission during the locking of the tool head on the tool holder takes place by means of pins

  with small transmission surfaces

  therefore not only very strongly

  but also subject to significant wear. This is all the more true as they are also solicited by dynamic shearing efforts as a result of the game

  due to the construction between the cylindrical engagement element

  drique and the cylindrical recption bore.

  In another known embodiment, the assembly between the tool head and the tool holder takes place by means of a hirth latch and a collet. The collet has several clamping elements which

  act on a retaining pin of the tool head.

  The disadvantage of this known construction lies in the indeterminacy of the connection between the head

  tool holder and the tool carrier as a result of the teeth of the

  Hirth, which must ensure not only the safety against the relative rotation between the tool head and the tool holder, but also at the same time the centering and the determination of the axial position. A division defect of the Hirth notching leads to an erroneous position in the axial direction and in the radial direction of the cutting edge of the tool head. Despite the use of a

  Hirth cranking of very expensive and complicated

  This known embodiment thus presents

  the disadvantage of low accuracy.

  The object of the invention is to arrange a device of the type described in the preamble for blocking tool heads on a machine tool holder, so that avoiding the disadvantages of the known embodiments and with a low construction cost, we get a mounting without play of the tool head on the tool holder. We must also obtain a well-defined centering and axial position, the centering game in front of

  to be as big as possible for the automatic change

tick of the tool head.

  For this purpose, the invention relates to a device of the above type, characterized in that the tool head

  is equipped with a short lateral surface for centering

  conical wedge, the tool holder being provided with a corresponding opposite conical side surface and in that, for determining the axial position of the tool head on the tool holder, a planar face is formed

  at the end of large diameter of each lateral surface

  said flat faces applying, in the clamping state by the axial traction force of the traction element, without play on one another, as well as the

conical side surfaces.

  By the arrangement according to the invention, with centering surfaces made in the form of conical side surfaces, there is a large centering stroke during the introduction of the tool head.

  on the tool holder, so that the automatic change

  tick of the tool head is possible without difficulty.

  In spite of this great centering stroke, a fixture without play of the tool head is obtained in the tightened state on the tool holder, a well-defined centering and a well-defined axial position being obtained because the centering and abutment surfaces are obtained. are distinct, so that redundancy indeterminacy is avoided. Due to the size of the centering and abutment surfaces, low and negligible wear and a low tendency to fouling are obtained. In addition,

  tion according to the invention is of economic manufacture.

  than. According to another characteristic of the invention, the tool head may be provided with a threaded hole in which a pulling screw arranged directly in the tool holder and acting as a traction element engages directly. This gives a simple and rigid assembly and automatic locking by the thread between

  the tool head and the tool holder.

  To achieve this construction, it is proposed according to the invention to mount the pulling screw in the tool holder so that it slides between two end positions and load it by a spring

  acting in the tightening direction of the tool head.

  By matching the end positions and the spring, it is obtained that, when the tool head is put in place, the pulling screw leaves the tool holder only until the conical centering surfaces

  cooperate for the preliminary centering and that security

  against the rotation acts, the thread of the traction screw engaging however just in the drilling

tapped on the tool head.

  According to a variant embodiment of the invention, an annular groove with trapezoidal section is formed in the tool head behind the inner conical side surface, clamping elements

  with radial adjustment engaging in this annular groove

  by clamping surfaces corresponding to said groove, said clamping members being displaced by axial movement of the pulling member. With a construction expense a little bigger,

  in this embodiment, a particular arrangement

  Firstly, it is safe against fouling and allows

  quick release and loosening of the tool head.

  According to a preferred embodiment,

  the traction element is provided with a displacement thread

  cement for the radial adjustment of the clamping elements.

  The rotation of a nut maintained without possibility of

  axial displacement then results in a displacement

  the axial element of the traction element provided with the thread and which, for this purpose, is maintained without the possibility of

rotation in the tool holder.

  Since rapid tightening and loosening of the tool head on the machine tool with simple elements is required, the draw element is, for the radial adjustment of the clamping element, according to the invention, constantly loaded by at least one spring in the tightening direction of the tool head and can be moved in the opposite direction by a force which can be applied from the outside, this force being produced, for example, by a cylinder solicited on one side. It is thus possible in a simple manner to automate the clamping operation

and loosening.

  Another possible embodiment consists in that the traction element can, for the radial adjustment displacement of the clamping elements, be actuated by a pressure fluid cylinder incorporated in the

  toolholders. This realization occurs if the holder

  tools already has pressurized fluid connections.

  Finally, it is proposed by the invention to make the clamping elements on a split clamping cartridge and to move them radially outwards by the conical head of the traction element against

  the inherent elasticity of the clamping cartridge. This agency

258157d

  known, according to various achievements, is

  to allow, with high operational safety, the use of conventional building

Trade.

  The description below relates to examples

  embodiment of the invention shown in the accompanying drawings, in which: - Figure 1 is a longitudinal section of a head

  of tool set up on a tool holder with a pre-

  first embodiment of the traction element at the beginning of the fixing operation, - Figure 2 is a view corresponding to Figure 1, but in the tight state,

  FIG. 3 is a longitudinal section corresponding to

  2, using a second embodiment of the traction element, FIG. 4 represents another embodiment of the traction element, by means of a sectional cut.

  longitudinal axis of a tool head blocked on the

  tools, - Figure 5 is a view corresponding to Figure 4, in the case of the use of a variant solution

  to actuate the traction element.

  FIG. 1 and FIG. 2 represent, according to a first embodiment, a tool holder 1 which, on the side carrying a tool head 2, is provided with an annular flat face serving as an abutment face for the head.

  2 which has a flat annular surface corres-

  2a. The flat face 1a of the tool holder 1 surrounds a short outer conical side surface 1b projecting from the tool holder 1. The taper angle of the outer conical side surface 1b corresponds to a value of between 1:10 and 1: 4. On this outer conical side surface lb can be engaged the head

  tool 2 by means of an integral conical

  2b which is formed in a central bore of the tool head 2 provided with one or more platelets of

cut 3.

  The safety of the tool head 2 against rotation

  With respect to the tool holder 1 is ensured in the embodiment examples represented by a key 4 fixed in the radial direction on the tool holder i in the area of the flat face la, this engaging key

  in a corresponding groove in the tool head 2.

  In the first embodiment of Figure 1 and Figure 2, it is used as an element

  traction, to lock the tool head 2 on the carrier

  tools 1, a traction screw 5 whose threaded portion engages in a threaded bore 2c of the tool head

  2. The draw screw 5 is guided by means of a glue

  annular ring 5a for sliding between two positions

  end in a bore 1c of the tool carrier 1. The posi-

  rear end is determined by the stop of

  the annular flange 5a on a stop ring 6. When

  that the tool head 2 is withdrawn, this end position

  The rear mite is obtained by a spring 7 disposed between the annular collar 5a and the bottom of the bore 1c of the tool holder 1, this spring loading the traction screw in the tightening direction of the tool head 2. The another end position, front, of the traction screw 5 is determined by the stop of its annular flange 5a

on the compressed spring 7.

  In the exemplary embodiment according to FIG. 1 and FIG. 2, an outer six-piece 5b is formed at the end of the traction screw 5. This six-piece makes it possible to turn the traction screw 5. The longitudinal dimensions are given between they so that the pulling screw 5 comes out of the tool holder 1, by its first thread turn according to Figure 1, just enough for that when setting up the

  the tool head 2 by its integral conical lateral surface.

  2b on the outer conical side surface 1b of the tool holder 1, the first thread turn engages

  when we turn the draw screw 5. We are thus

  that preliminary centering takes place by means of the conical side surfaces 1b and 2b and that there is a security against the rotation by the key 4, if the tool head 2 is put in place automatically or at the hand on the tool holder 1 for blocking. The rotation of the pulling screw 5 therefore causes the tool head 2 to be properly locked. A play without tightness is thus obtained by the conical side surfaces 1b and 2b as well as by the abutment of the flat faces 1a. and 2. When loosening the pulling screw 5, the spring 7 acts so that this pulling screw 5 is brought back into the tool holder 1 according to the loosening operation, so that the tool head 2 retains its clamping position until the output of the draw screw 5 out of the tapped bore 2c of the tool head

  2. The tool head 2 can therefore also be removed automatically.

  tool holder 1 at the end of the operation

loosening.

  In the second embodiment according to FIG. 3, an annular groove 2d with trapezoidal section is formed in the tool head 2 behind the surface.

  internal conical side 2b. In this annular groove

  2d engage clamping elements 8a to

  radial element, these elements having clamping surfaces corresponding to the annular groove 2d. In the exemplary embodiment shown, the elements of

  8a are formed on a clamping cartridge 8.

  These clamping elements 8a are moved radially by the conical head 9a of a pulling member 9 against the inherent resilience of the clamping cartridge 8 when the pulling member 9 is moved in the direction of

  axial with respect to the tool holder 1.

  In the embodiment shown in FIG. 3, the axial displacement of the traction element 9 takes place by means of a movement thread formed at the end of the traction element 9 in the form of an external thread. and in the front portion of a nut provided with a key surface 10a. While the nut 10 is mounted for rotation in the tool holder 1, the pulling member 9 is held rotatably by a set screw 11. As a result, the rotation of the nut 10 results in movement. axial of

the traction element 9.

  Blocking and loosening of the tool head 2 take place in the embodiment according to FIG. 3 as in the first embodiment of FIG. 1 and FIG. 2. The clamping elements 8a can then, for the purpose of in place and removing the tool head 2, be moved radially inward due to their own resilience by the head 9a, of the pulling member 9, which is outwardly forward, to such an extent that the tool head

  2 can be engaged and removed without difficulty.

  The third embodiment according to FIG. 4 differs from the embodiment according to FIG. 3 by the mode of action of the traction element 9 acting on the clamping elements 8a of the cartridge.

tightening 8.

  In this embodiment, the traction element 9 is guided, by an annular collar 9b screwed onto the rear end, to slide in a bore 1c of the tool holder 1. This traction element 9 is loaded in the direction of tightening of the tool head 9 by a spring force which, in the exemplary embodiment shown, is constituted by a series of Belleville washers 12. Thus, as a result of the force of the Belleville washers 12, the clamping elements 8a are constantly in the tightening position. If a tool head 2 is to be removed and a new tool head 2 to be set up, it is necessary to move the pulling element 9 by a force applied from the outside in the direction of the indicated arrow. in FIG. 4, this force exceeding that of the Belleville washers 12. The clamping elements 8a then move radially inwards because of their inherent elasticity to allow the removal or setting up of the tool head 2 As soon as it has been removed by the force applied from the outside, the Belleville washers 12 move the traction element

  9 in the tightening direction of the tool head 2.

  As a result, the head 9a of the traction element 9 moves the clamping elements 8a away from the clamping cartridge 8 and blocks the tool head 2 put in place by

  through the annular groove 2d of the carrier

tools 1.

  In the fourth embodiment following

  In Figure 5, the difference in construction lies simply

  In this embodiment, the pulling member 9 carries a piston 9c guided to slide in a cylindrical chamber 1d of the tool holder 1. The cylindrical chamber 1d is rendered sealed by a cover vis-à-vis the other elements of the tool holder 1 and is provided with pressurized fluid connections If, so that the piston 9c can be moved in both directions under

  the action of the fluid under pressure. By an appropriate order

  asked for the arrival and evacuation of the fluid

  pressure, it is therefore possible to tighten and loosen

  rage of the clamping elements 8a of the clamping cartridge 8, so that the tool head 2 can be,

  in the same way as before, blocked on the door-

tools 1 or removed from it.

ill

Claims (8)

  1. Device for locking tool heads with at least one edge for machining by chip removal, on a machine tool holder which does not rotate during machining, with center surfaces formed on the tool head and the tool holder as well as with abutment faces for determining the axial position, an axially displaceable pulling element being provided for fixing the tool head to the tool holder, the tool head being guaranteed against rotation relative to the tool holder by a groove and key joint, characterized in that the head   tool (2) is provided for centering a short over-   conical side face (2b), the tool holder (1) being   with an opposite conical side surface corresponding   dante (lb) and in that for determining the posi-   axial direction of the tool head (2) on the tool holder (1), a flat face (1a, 2a) is formed at the end of large diameter of each conical side surface (1b, 2b), these faces planes applying, in the clamping state by the axial traction force of the traction element   (5,9), with no play on each other, as well as over- conical side faces (lb, 2b).   2. Device according to claim 1, characterized   in that the tool head (2) is provided with a threaded hole (2c) in which a pulling screw (5) is arranged directly in the tool holder (1) and   acting as a traction element (5).   3. Device according to any one of the   cations 1 and 2, characterized in that the pulling screw (5) is mounted in the tool holder (1) to slide between two end positions, this screw being loaded by a spring (7) acting in the direction of Tightening the tool head (2).   4. Device according to claim 1, characterized 258157:   in that an annular groove (2d) with a cross-section   in the tool head (2) behind the inner conical side surface (2b), radial clamping elements (8a) are engaged in said annular groove by clamping surfaces corresponding to said groove. annular (2d) these elements of   tightening being displaced by axial movement of the element traction force (9).   5. Device according to claim 4, characterized   in that the traction element (9) is provided with a displacement thread for the radial adjustment of the clamping elements (8a).   6. Device according to claim 4, characterized   characterized in that the traction element (9) is, for the radial adjustment of the clamping elements (8a), loaded   constantly by at least one spring (12) in the direction   tightening of the tool head (2) and can be   moved in the opposite direction by a force that can be applied from the outside.   7. Device according to claim 4, characterized   in that the traction element (9) is actuated for the radial adjustment of the clamping elements (8a).   by a pressure fluid cylinder (ld, 9c, le) incor- pored in the tool holder (1).   8. Device according to any one of the   1 to 7, characterized in that the clamping elements (8a) are formed on a clamping cartridge   slotted (8), these elements being able to be displaced radially   outwardly through the conical head (9a) of the traction element (9) against the inherent elasticity the clamping cartridge (8).