DESCRIPTION

The present invention relates to the field of connections for tools and more particularly to the field of floating connections for tools.

During a boring operation using a cutting tool, it is common to mount the latter, in the form of a cutting head, at the end of a spindle. In order to facilitate the boring operating, the spindle which supports the cutting head is itself mounted on a floating tool holder. On a machine comprising a spinning motor, a floating tool holder of this kind enables a displacement of the axial structure that it supports in directions perpendicular to the spindle that supports the cutting head.

During a boring procedure it is usual for a pre-drilled hole to have already been formed. The cutting head of the boring tool is then aligned so as to be arranged opposite said pre-drilled hole, and then inserted into the latter to proceed with the boring operation.

However, the alignment of the boring tool relative to the pre-drilled hole is not always accurate. The presence of a floating tool holder then makes it possible to correct this inaccurate positioning by enabling an adjustment between the driving spindle of the spinning motor and the working spindle of the cutting head of the boring tool. The floating tool holder, because of the displacement that it enables, thus facilitates the boring by enabling a tolerance of the positioning of the driving spindle in rotation. This relative flexibility thus makes it possible to facilitate the alignment of position of the cutting head and avoids the formation of a bore that is offset in relation to the pre-drilled hole or larger than the latter.

However, the mechanisms of such floating tool holders are particularly complex to construct and achieve. Furthermore, such floating tool holders are soon limited in their application when used in a structure of small size. This type of situation is encountered particularly in the field of automatic lathes. An aspect of the present invention is to overcome these disadvantages by proposing a mechanism with a simplified structure and implementation and which can be used in structures of a smaller size than those able to include floating tool holders.

The subject matter of the invention is thus a floating connection for a tool comprising:

- an axial structure a first end of which forms a connecting interface with a coupling interface part,

wherein the connecting interface with the coupling interface part is formed by a male structure designed to cooperate with a female structure of the coupling interface part, the cross section of the female structure being wider than the cross section of the male structure so as to enable a displacement of the axial structure in at least two different directions, and

wherein the floating connection also comprises:

- a cutting support interface for mounting a cutting structure mounted at a second end of the axial structure.

The invention also relates to a boring device comprising a spinning motor means, which includes at least one floating connection according to the invention.

The invention is explained in the following description which relates to a preferred embodiment, given by way of a non-limiting example, and explained with reference to the attached schematic drawings in which:

- Figure 1 is a schematic representation of a first exemplary embodiment of a device according to the invention,

- Figure 2 is a schematic representation of a first exemplary embodiment of a device according to the invention without a cutting tool,

- Figure 3 is a schematic representation of a cross section of a first exemplary embodiment of a device according to the invention,

- Figure 3bis is a schematic representation of a detail of the adjusting element of the device shown in Figure 3,

- Figure 4 is a schematic representation of a second exemplary

embodiment of a device according to the invention,

- Figure 5 is a schematic representation of a second exemplary

embodiment of a device according to the invention without a cutting tool, - Figure 6 is a schematic representation of a cross section of a second exemplary embodiment of a device according to the invention,

- Figure 7a is a schematic representation in a transparent view of a cardan type connection of a second exemplary embodiment of a device according to the invention,

- Figures 7b, 7c and 7d are different schematic representations of cross sections detailing a cardan type connection of a second exemplary embodiment of a device according to the invention,

- Figure 8 is a schematic representation of a cross section of a third exemplary embodiment of a device according to the invention.

The present invention relates to a floating connection 1 for a tool comprising:

- an axial structure 2 a first end 2a of which forms a connecting interface 3a with a coupling interface part 4,

wherein the connecting interface 3a with the coupling interface part 4 is formed by a male structure designed to cooperate with a female structure of the coupling interface part 4, the cross section of the female structure being wider than the cross section of the male structure so as to enable a displacement of the axial structure 2 in at least two different directions, and

wherein the floating connection 1 also comprises:

- a cutting support interface 3b for supporting a cutting structure 5 mounted at a second end 2b of the axial structure 2.

The formation of such a floating connection 1 thus involves at the same time, on the one hand a connection with the coupling interface part 4 and on the other hand a support and transmission of torque to the cutting structure 5 which is mounted on the axial structure 2. A construction of this kind also makes it possible to preserve the displacement properties of the axial structure 2 relative to the coupling interface part 4.

Furthermore, the positioning of the floating connection 1 close to the cutting structure 5 makes it possible to use the floating connection 1 of the invention in a structure that takes up little space.

According to a feature of the embodiment the floating connection 1 has a tool holder also comprising at least one centering element 6 mounted on the periphery of the male structure of the connecting interface 3a with a coupling interface part 4 and designed to be in contact with the internal wall of the female structure of the coupling interface part 4. This centering element 6, while being in contact with the internal wall of the female structure of the coupling interface part 4, makes it possible on the one hand to maintain a distance between the surface of the male structure and the internal surface of the female structure and on the other hand to ensure a coaxial repositioning of the male structure with the female structure of the part 4. However, the resilient features of this centering element 6 enable a displacement of the male structure of the axial structure 2 of the tool holder 1 in the female structure of the coupling interface part 4 in at least one direction perpendicular to the axis of the axial structure 2. This centering element 6 thus enables a centering of the axial structure 2 on the axis of rotation of the coupling interface part 4 while enabling a displacement of this axial structure axial 2 relative to the axis of rotation. Furthermore, by means of its elastic properties, this centering element 6 can also perform a shock-absorbing function during the displacement of the male axial structure 2 in the female structure of the part 4.

According to a preferred type of structure, this centering element 6 is formed by a resilient ring arranged on the connecting interface 3a with a coupling interface part 4. It should be noted that the floating connection 1 of the invention can comprise a plurality of resilient rings positioned in a juxtaposed manner on the same portion of the connecting interface 3a.

According to a special feature of this embodiment, the floating connection 1 has at least one centering element 6 being arranged in a groove 7 formed in the periphery of the male structure 2a or the internal face of the female structure of the connecting interface 3a with a coupling interface part 4. Said groove 7 makes it possible to hold the centering element 6 in position during repeated displacements of the axial structure 2 in the coupling interface part 4. Said groove 7 can be positioned on the periphery of the axial male structure 2 or alternatively on the internal face of the female structure of the part 4.

According to another complementary feature of this embodiment the floating connection 1 has at least one centering element 6 being positioned on the connecting interface 3a, close to the opening 4a of the female structure of the coupling interface part 4. This particular arrangement makes it possible to obtain a recentering, or even damping, on the part of the male structure, the displacement of which is greater on the inside of the female structure of the part 4. In fact, when the end of the male structure formed by the axial structure 2 is fixed to the inside of the female structure formed by the coupling interface part 4, this zone or attachment point forms a fixed point around which there is a displacement by pivoting the axial structure 2.

According to a feature of the embodiment of the floating connection 1 of the invention, the latter also comprises at least one element 8 for adjusting the displacement of the axial structure 2.

According to a preferred embodiment of this feature the element 8 for adjusting the displacement is formed by a rigid annular structure mounted on the axial structure 2 and comprising at least one part 8a designed to be inserted, at the opening 4a of the female structure of the coupling interface part 4, between the peripheral surface of the axial structure 2 and the internal surface of the female structure of the coupling interface part 4. This insertion of a part 8a of the adjusting element 8 enables a reduction of the size of the displacement of the axial structure 2 on the inside of the female structure of the coupling interface part 4. The inserted part 8a of the adjusting element 8 being positioned on the peripheral surface of the axial structure 2 makes it possible to reduce the displacement space between this peripheral surface of the axial structure 2 and the internal face of the female structure of the coupling interface part 4.

According to a feature of the embodiment the adjusting element 8 comprises a part 8a for insertion which has portion 8b with a conical or bevelled shape for insertion between the peripheral surface of the axial structure 2 and the internal surface of the female structure of the coupling interface part 4 and for limiting the displacement of the axial structure 2, the portion 8b with a conical or bevelled form being able to interact with a flange edge 4b adapted to the opening 4a of the female structure of the coupling interface part 4. Said portion 8b with a conical or bevelled form is oriented towards the opening of the driving part 4 to facilitate the insertion of the adjusting element 8. Said portion 8b with a conical or bevelled form of the coupling interface part 4 preferably comprises a surface in contact with the peripheral surface of the axial structure 2 against which the adjusting element 8 bears. In a complementary manner, the inner edge of the opening 4a of the coupling interface part 4 comprises a surface inclined in relation to the internal surface of the female structure of the coupling interface part 4. This inclination of the surface is then adapted to have an angle

substantially identical to that of the bevel formed on the part to be inserted of the adjusting element 8.

According to another complementary feature of the embodiment, the adjusting element 8 comprises an annular structure mounted concentrically on a part of the axial structure 2 and interacting at least by sliding relative to the axial structure 2.

According to a first feature of the structure, the sliding of the adjusting element 8 is performed by means of a tapped interface 2c with a threaded portion 8c of the annular structure. This screw/nut type of interaction thus enables an axial displacement of the adjusting element 8 along the axial structure 2 by a simple pivoting of the adjusting element 8 around the spindle of the axial structure 2. The sliding of the adjusting element 8 along the spindle of the axial structure 2 by means of an axial pivoting thus enables a controlled displacement of the adjusting element 8 during its insertion into the interval separating the axial structure 2 from the internal surface of the female structure of the coupling interface part 4.

According to an alternative feature of the structure, the sliding of the adjusting element 8 is performed by means of a continuous or step by step adjusting mechanism. This continuous or step by step adjusting mechanism according to an example of the known type can involve a removable part connected to the adjusting element 8 and designed to interact with housings on the surface of the axial structure 2 and arranged respectively at the

incrementation level corresponding to different possible positions of the adjusting element 8.

With regard to the connection of the axial structure 2 to a coupling interface part 4, according to a first feature of the embodiment the end of the connecting interface of the axial structure 2 with a coupling interface part 4 involves a rigid connection (tight). According to a first exemplary embodiment, said rigid connection (tight) can comprise a threaded face 9a of the axial structure 2 designed to interact with a tapped interface of the female structure of the drive part 4. According to alternative examples of a tight connection, the axial structure 2 is mounted by frettage to the coupling interface part 4 or even by welding. The connecting interface thus preferably causes the axial structure 2 to interact with a part of the coupling interface part 4 at a distance from the opening 4a of this part 4. Said connecting interface at a distance from the opening 4a enables an attachment which allows displacement by bending and or by pivoting of the axial structure 2 in the opening of the female structure of the driving coupling interface part 4. With this kind of type of tightened assembly, the displacement is then essentially due to the axial flexibility of the axial structure 2.

According to a second feature of this connection of the axial structure 2 to the coupling interface part 4, the connection involves an intermediate resilient structure 1 1 . Said intermediate resilient structure 1 1 enables an attachment which allows displacement by pivoting but also by radial displacement of the axial structure 2 in the opening of the female structure of the driving coupling interface part 4. A displacement of this kind is then essentially due to the resilient properties of the intermediate structure 1 1 which enables its deformation during a displacement of the axial structure 2 relative to the coupling interface part 4.

According to a non-limiting exemplary embodiment, said resilient intermediate structure 1 1 can be made from an elastomer.

According to an alternative feature of the invention the end of the connecting interface with a coupling interface part 4 involves a cardan type connection 9b with the female structure of the coupling interface part 4. Said cardan type connection 9b enables the attachment of the axial structure 2 at a double articulation point. The displacement of the axial structure 2 is then enabled by means of said cardan connection 9b, a first part of which forms the body of the axial structure 2 and a second part is mounted so as to be fixed in translation and rotation to the coupling interface part 4.

According to a complementary feature of the embodiment, the axial structure 2 comprises a pipe 10 which is adapted to allow the flow of fluid through its structure 2 from the connecting end 9a, 9b in contact with the coupling interface part 4 to the end holding the cutting tool 5. A pipe of this kind 10 thus makes it possible to transport the lubricant to the cutting surface, or alternatively a cooling liquid. According to a non-limiting structural feature of the invention, when the connection end is a cardan type connection 9b, the opening of the pipe 10 close to the cardan connection 9b is formed by one or more grooves arranged on either side of the cardan connection 9b and open in the direction of the base of the female structure of the coupling interface part 4.

The invention also relates to a boring device comprising a spinning motor means, which integrates at least one floating connection 1 according to the invention. According to a non-limiting structural feature of the invention, the motor is connected to the coupling interface part 4.

Of course, the invention is not limited to the embodiment described and represented in the attached drawings. Modifications are still possible, particularly with regard to the structure of the various elements or by substituting equivalent techniques, without departing as such from the scope of protection of the invention.

The disclosures in French Patent Application No. 14 53489, from which this application claims priority, are incorporated herein by reference.