Device with mechanical immobilisation of the cutting inserts for tools of machine tools

MECHANICAL LOCKING DEVICE FOR CUTTING INSERTS FOR MACHINE TOOLS TOOLS

-1 The present invention relates to a device comprising a base plate (1) and an insert (2) made of cutting material such as polycrystalline diamond (PKD) or cubic boron nitride (CBN).

The traditional manufacture is a tungsten carbide insert to which the insert of cutting material is brazed.

The device according to the invention makes it possible to remedy the brazing of the inserts and its drawbacks, to eliminate the resharpening of the inserts and to ensure the rapid change of the inserts on the base insert after wear.

The device comprises, according to a first characteristic, a base plate (1) of square, rectangular, triangular, rhombic or other shape, made of spring steel or high speed steel treated at around 62 HRc or other materials such as carbide. of tungsten. The base plate (1) has a housing of particular shape, adapted to receive the cutting insert (2). Each insert housing has a minimum of two tabs. Each lug is formed by 3 or more tapered slopes. The slopes constituting these lugs are inclined from T to 45 *. the optimum slopes being around 15 *.

According to a second characteristic, the device comprises an insert (2) of particular shape, made of a cutting material such as polycrystalline diamond (PKD) or cubic boron nitride (CBN). The insert (2) has a complementary shape which fits in the housing of the base plate (1). it has two lugs housings in which the lugs of the base plate (1) are housed. These lug housings are formed by conical slopes with angles corresponding to those of the base plates.

The user places the insert (2) - FIG. 3, cutting face and large face of the lugs housing upwards, and covers this insert with the base plate (1), large face of the lugs upwards. The two lugs of the base insert (1) fit into the two lugs of the cutting insert (2) by pressing the insert (1) down. The tapered slopes of the lugs fit into the conical lugs of the inserts and ensure the centering and locking by wedging the insert (2) in its plate (1).

-2The device can be tightened by pressing the plate (1) on its insert (2) by a wedge or a flange placed on the upper face of the base plate (1) - FIG. 4; or placed on the underside of the insert (2) FIG. 5; or by a screw placed in the base plate (1) - FIG. 6.

Disassembly of the device is done by loosening the upper or lower corner when loosening the fixing screw.

The insert (2) is removed from its plate (1) by pressing the plate on its underside and pushing the insert downwards - FIG. 7. (To allow disassembly, the insert must not bear on its underside.)

According to particular embodiments, the base plate (1) can be made of any material and in particular of spring steel, high speed steel or tungsten carbide. Shapes and sizes can be made according to ISO standards or special shapes and sizes.

The base plate (1) - FIG.1 has a housing of particular shape to receive the cutting insert. This housing has at least two locking and centering pins. Each lug is produced by at least 3 tapered slopes. These slopes are machined with inclinations from T to 45 * (optimum angle 15 *). The largest section of the lug is located towards the top. The position of the pins is made so that the insert is pulled into the bottom of the insert housing when locking. The housings and the realization of the pins are obtained by cutting in wire EDM.

The insert (2) - FIG. 2 is made of a cutting material such as polycrystalline diamond (PKD) or cubic boron nitride (CBN) with a shape corresponding to its housing in the base plate (1). In the insert are made at least two housings of conical lugs (large face up), in which are housed the two lugs of the base plate. These lugs housings are made with conical slopes of 7 * to 45 * identical to those of the slopes of the lugs of the base plate (1). The inserts (2) are cut by wire EDM and sharpened on request.

The insertion of the insert (2) in the base plate (1) must not be complete. A residual overflow on the lower face of about 0.1 mm should remain - FIG. 3, to ensure positive locking of the assembly and to prevent any play after fitting and tightening the insert in its housing.

-3The position of the lugs of the base plate (1) is included in an angle between 60 * and 160 *.

The device according to the invention is particularly recommended for the replacement of traditional inserts with brazed inserts used on the tool holders of machine tools in mechanical construction workshops. It allows easy assembly of the insert (2) and its replacement after use. The low manufacturing cost of the insert (2) eliminates the need for resharpening. The base insert (1) can accommodate inserts (2) in different cutting materials.