Clamping device for a tool holder

Abstract

A clamping device for releasably holding a toolholder shank (91), comprising: a housing (2); a drawbar (5) axially movable within a bore (3) in the housing; an engagement member (20) movable under the influence of the drawbar and in locking engagement with the toolholder shank; and an actuating member (14) rotatably arranged within the bore. When the actuating member rotates, a contact surface of a motion-transmitting element (50) fixedly connected to the actuating member presses against a contact surface of another motion-transmitting element (40) fixedly connected to the drawbar, thereby achieving axial movement of the drawbar. At least one of the contact surfaces comprises two sections having a mutually different pitch, whereby the same angular displacement of the actuating member when rotated in a first rotational direction results in a longer axial movement of the drawbar in a first phase of its rotational movement than in a final phase.

Description

Technical Field

[0001] The present invention relates to a clamping device as described in the preamble of claim 1, which is intended to be used for connecting a tool holder to a machine tool.

Background Art

[0002] In the field of machine tools for metal cutting, cutting tools in the form of, for example, drills, milling tools or lathe tools, which are used for machining workpieces of metal materials, are often fixed to a tool holder, and the tool holder may be removably fixed to a clamping device attached to the machine tool. It has been conventionally known to clamp the shank of such a tool holder to the housing of the clamping device by a clamping mechanism arranged within the housing. Tool holders for cutting tools in the form of drills and milling tools are usually clamped to a rotatable housing in the form of a spindle, while tool holders for lathe tools may be clamped to a non-rotatably arranged housing. When it is necessary to replace the cutting tool, the tool holder is released from the housing of the clamping device, and a new tool holder having another cutting tool is clamped to the housing. This type of clamping device may be removably fixed, for example, around a tool turret included in a machine tool.

[0003] Many of the conventionally known clamping devices of the above type require manual operation to clamp or release the tool holder. There are also clamping devices adapted for automatic tool change operations, for example, a hydraulic piston is used to control the state of the clamping mechanism. However, such automatically operating clamping mechanisms are usually quite bulky and require a lot of space, especially in the longitudinal direction, and therefore are not suitable for use in a tool turret of a machine tool where the axial space available for the clamping device is limited.

[0004] A clamping device comprising a housing in the form of a spindle having a clamping mechanism adapted to an automatic tool change operation is conventionally known from European Patent No. 1468767. In the clamping device according to European Patent No. 1468767, an operating member in the form of a first tension rod is slidably mounted inside the spindle and is configured to effect an axial displacement of a second tension rod via a force amplification mechanism provided with several cooperating wedges arranged between the tension rods. A gas spring inside the spindle is configured to bias the two tension rods to a retracted locking position where the tool holder is clamped to the spindle, and a hydraulic piston may be configured to act on the piston at the rear end of the gas spring to achieve a displacement of the two tension rods to a forward release position where the tool holder can be released from the spindle. However, this conventionally known clamping device has a relatively long axial range and is therefore not suitable for use with this type of clamping device when the tool holder is removably fixed around a tool turret where the axial space available for the clamping device is limited.

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] An object of the present invention is to provide a clamping device of the above type having a novel and advantageous design and suitable for use with a tool turret of a machine tool.

MEANS FOR SOLVING THE PROBLEMS

[0006] According to the present invention, the above object is achieved by a clamping device having the features defined in claim 1.

[0007] The clamping device according to the present invention - a housing having a front end portion, a rear end portion, and a bore intersecting the front end portion and extending rearward from the front end portion, wherein an attachment portion for receiving the tool holder shank is provided at the front end of the bore; a housing, - A tension rod slidably mounted inside the bore so as to be reciprocally movable within the bore along its longitudinal axis between a forward release position and a rearward lock position; - An engagement member disposed around the tension rod at the front end of the tension rod, the engagement member being movable from a first position in which the tool holder shank can enter and exit the mounting portion of the bore by the engagement member under the influence of the tension rod moving from the forward release position to the rearward lock position, to a second position in which the engagement member locks and engages with the tool holder shank and keeps the tool holder shank fixed to the housing; an engagement member; - An actuating member rotatably disposed within the bore so as to be rotatable about the longitudinal axis, the actuating member being axially fixed relative to the housing so as to be prevented from moving along the longitudinal axis; an actuating member; - A motion transmission mechanism disposed inside the housing, the motion transmission mechanism being configured to transmit the rotational movement of the actuating member in a first rotational direction with respect to the housing to the axial movement of the tension rod from the forward release position to the rearward lock position; comprising.

[0008] The above-mentioned motion transmission mechanism is - A first motion transmission element fixed to or fixedly connected to the tension rod so as to be movable along the longitudinal axis together with the tension rod, the first motion transmission element being provided with a first pressure-receiving contact surface facing the front end portion of the housing; - A second motion transmission element fixed to the actuating member so as to be rotatable with respect to the housing and the tension rod together with the actuating member, the second motion transmission element being provided with a first pressurizing contact surface facing the rear end portion of the housing for contacting the first pressure-receiving contact surface, the first pressurizing contact surface being configured to press the tension rod from the forward release position to the rearward lock position by sliding and pressing against the first pressure-receiving contact surface when the actuating member is rotated in the first rotational direction; a second motion transmission element; comprising.

[0009] By using the above-described actuating member and motion transmission mechanism to control the axial movement of the tension rod, it means that a gas spring or the like that occupies a large amount of space axially is not required to control the axial movement of the tension rod, and the clamping device can be made space-saving axially. Therefore, this clamping device is suitable for use in a tool turret.

[0010] According to the present invention, at least one of the above-described contact surfaces, that is, at least one of the first pressure-receiving contact surface and the first pressing contact surface, includes a first contact surface section and a second contact surface section arranged at different positions along the associated motion transmission element. Thereby, when the actuating member moves in the first rotational direction, the first contact surface section is configured to slide relative to the other contact surface during the first stage of the movement, where the second contact surface section is configured to slide relative to the other contact surface during the final stage of the movement. The first contact surface section has a larger pitch than the second contact surface section. Thereby, the same angular displacement of the actuating member associated with the rotation of the first rotational direction with respect to the housing results in a larger axial movement of the tension rod in the first stage than in the final stage. Thereby, the tension rod can move axially rapidly during the initial stage of clamping under the influence of the larger pitch. This initial clamping stage does not require a large force. However, the final stage of clamping requires a larger force. When the actual clamping is performed, that is, when the engaging member takes the above-described second position, the tension rod moves axially under the influence of the smaller pitch. Thereby, the axial movement of the tension rod becomes smaller compared to the angular displacement of the actuating member, and as a result, a force amplification effect, also called "output boost", occurs. By using a larger pitch for the initial axial movement of the tension rod, it becomes possible to achieve the entire axial movement of the tension rod from the forward release position to the rearward lock position with a relatively small angular displacement of the actuating member.

[0011] The above-mentioned housing of the clamping device may have the form of a rotatable spindle and may be connected or connectable to a drive mechanism within a tool turret of a machine tool. However, the clamping device of the present invention is not limited to use in a tool turret, and such a housing in the form of a rotatable spindle may alternatively constitute the main spindle of a machine tool or be connected to such a spindle without an intermediate tool turret. When the housing has the form of a rotatable spindle, the clamping device may be used to clamp a tool holder provided with a drill or milling tool or other type of rotary tool. The housing included in the clamping device of the present invention may, as a further alternative, be a non-rotatable housing. In the latter case, the clamping device may be used to clamp a tool holder provided with a lathe tool or other type of non-rotary tool.

[0012] According to an embodiment of the present invention, the pitch is constant along the second contact surface section. The pitch is also preferably constant along the first contact surface section, although of course larger than the pitch of the second contact surface section. By using a constant first pitch along the first contact surface section and / or a constant second pitch along the second contact surface section, the manufacture of the motion transmission element is facilitated. However, alternatively, the first contact surface section and / or the second contact surface section may have a pitch that varies along the contact surface section in question.

[0013] The second contact surface section is preferably positioned on the relevant motion transmission element adjacent to the first contact surface section such that the second contact surface section follows immediately after the first contact surface section. However, alternatively, one or more intermediate contact surface sections having a constant or varying pitch deviating from the pitch of the first and second contact surface sections may be provided between the first and second contact surface sections on the motion transmission element in question.

[0014] According to another embodiment of the present invention, when the tension rod is pushed into the retracted lock position under the action of the actuating member and the first and second motion transmission elements, the second contact surface section has a pitch such that the first and second motion transmission elements keep the actuating member in a self-locking rotation position with respect to the tension rod. Thereby, the tension rod can be held in the retracted lock position without requiring an external force from the actuator, which means that the actuating member only needs to receive an external force from an actuator, for example in the form of a hydraulic actuator, in relation to the tool changing operation.

[0015] According to another embodiment of the present invention, the motion transmission mechanism is configured to transmit a rotational movement of the actuating member in a second rotational direction opposite to the first rotational direction to an axial movement of the tension rod from the retracted lock position to the advanced release position. Thereby, the actuating member may also be used to move the tension rod from the retracted lock position to the advanced release position in relation to the tool changing operation.

[0016] According to another embodiment of the present invention, the motion transmission mechanism comprises two or more sets of such motion transmission elements, each set comprising a first motion transmission element and an associated second motion transmission element, and these sets are circumferentially spaced apart from each other on the actuating member. The sets are preferably evenly distributed circumferentially on the actuating member. Thereby, a balanced clamping device with a good force distribution is obtained.

[0017] Further advantageous features of the clamping device according to the present invention will become apparent from the following description and the dependent claims.

[0018] Hereinafter, embodiments of the present invention given as examples will be specifically described with reference to the accompanying drawings.

Brief Description of the Drawings

[0019]

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DETAILED DESCRIPTION OF THE INVENTION

[0020] The clamping device 1 according to different embodiments of the present invention is shown in FIGS. 1 to 23. The clamping device 1 is configured to releasably clamp a tool holder 90 (shown very schematically in the drawings) to the housing 2 of the clamping device, enabling machining of a workpiece by a cutting tool (not shown) fixed to the tool holder 90.

[0021] The housing 2 has a front end portion 2a, a rear end portion 2b, and a bore 3 that intersects the front end portion 2a and extends rearward from the front end portion 2a. Thus, the bore 3 has an inlet opening 3a at the front end portion 2a of the housing.

[0022] In the embodiment shown in FIGS. 1 to 11, the housing 2 has the form of a machine spindle, and this spindle-shaped housing 2 may be rotatably mounted in a surrounding casing by a rolling bearing. In this case, the housing 2 may be connectable to a drive mechanism of a machine tool, for example, a drive mechanism in a tool turret of a machine tool, in order to enable the housing 2 to be rotationally driven by the drive mechanism.

[0023] In the embodiment shown in FIGS. 12 to 23, the housing 2 is designed as a non-rotatable housing. In this case, the housing 2 is connectable to a tool turret of a machine tool via a connecting member 4 extending from the housing 2 at its rear end portion.

[0024] The tension rod 5 is slidably mounted inside the bore 3 so as to be reciprocally movable along its longitudinal axis L within the bore 3 between a forward release position (see FIGS. 4 and 16) and a rearward lock position (see FIGS. 1 and 14). The tension rod 5 has a front end portion facing the inlet opening 3a of the bore 3 and a rear end portion on the opposite side. A head portion 6 and a neck portion 7 are provided at the front end portion of the tension rod 5. The head portion 6 is located in front of the neck portion 7 when viewed in the longitudinal direction of the tension rod, and the head portion 6 is connected to the neck portion 7 via a rearward inclined surface 8 of the head portion 6. A seal ring 9 is disposed between the tension rod 5 and the inner surface of the bore 3. In the illustrated example, this seal ring 9 is received in a groove on the outside of the tension rod 5.

[0025] At the front end portion of the bore 3, there is provided an attachment portion 10 for receiving the attachment shank 91 of the tool holder 90. This attachment shank 91 is herein referred to as the tool holder shank.

[0026] In the embodiment shown in FIGS. 12 to 23, the housing 2 includes a base portion 12 and an end piece 13 attached to the base portion 12 at the front end portion 2a of the housing. The end piece 13 has the form of a sleeve having an axially through hole that forms a part of the above-described bore 3. In this case, the above-described attachment portion 10 is located within the end piece 13.

[0027] In the embodiment shown in FIGS. 1 to 11, the portion of the housing 2 that houses the bore 3 is integrally formed without the end piece 13 of the above-described type.

[0028] The tool holder shank 91 is insertable into the mounting portion of the bore 3 through the inlet opening 3a at the front end portion 2a of the housing 2. The head portion 6 of the tension rod is received within the engagement bore 92 in the tool holder shank 91, and the tubular wall 93 of the tool holder shank is received within the space between the head portion 6 and the inner surface of the bore 3. In the illustrated embodiment, the mounting portion 10 of the bore 3 is conical and has a somewhat "triangular" or polygonal non-circular cross-sectional shape adapted to receive a similarly shaped tool holder shank 91. The conical shape ensures a radially and axially play-free connection between the tool holder shank 91 and the housing 2, while the non-circular cross-section ensures a non-rotatable fixation of the tool holder shank 91 to the housing 2. However, the mounting portion 10 of the bore 3 may also have any other suitable shape for receiving other types of tool holder shanks.

[0029] The engagement member 20 in the form of a segment is arranged around the tension rod 5 at the front end portion of the tension rod 5. Under the influence of the movement of the tension rod 5 from the forward release position to the rearward lock position, the engagement member 20 moves from a first position (see FIGS. 4 and 16) in which the tool holder shank 91 can enter and exit the mounting portion of the bore 3 by the engagement member 20 to a second position (see FIGS. 1 and 14) in which the engagement member 20 is in locking engagement with the engagement groove 94 in the engagement bore 92 of the tool holder shank 91, thereby keeping the tool holder shank 91 fixed to the housing 2.

[0030] In the illustrated embodiment, the engagement member 20 is disposed around the neck portion 7 of the tension rod 5 and is held in a fixed position around the neck portion by a retainer ring 21 disposed in the bore 3 and surrounding the neck portion 7 and an elastic O-ring 22. Each engagement member 20 has an outward flange portion 23 that engages with the inner groove of the retainer ring 21. The O-ring 22 is received in an outward groove at the rear end of each engagement member 20. A compression spring 24 is also disposed in the bore 3 and is configured to surround the tension rod 5. In the embodiments shown in FIGS. 1 to 11, the compression spring 24 is attached between the shoulder of the tension rod 5 and the thrust ring 25, and in the embodiments shown in FIGS. 12 to 23, the compression spring 24 is attached between the shoulder of the tension rod 5 and the retainer ring 21. The compression spring 24 is configured to bias the retainer ring 21 and the engagement member 20 forward. In the embodiments shown in FIGS. 1 to 11, the forward movement of the retainer ring 21 toward the inlet opening of the bore 3 is restricted by a stop ring 26 attached to the groove on the inner surface of the bore 3. In the embodiments shown in FIGS. 12 to 23, the forward movement of the retainer ring 21 toward the inlet opening of the bore 3 is restricted by the shoulder on the inner end face of the end piece 13.

[0031] Each engagement member 20 is provided at its front end with an outward engagement flange 27 configured to engage with the engagement groove 94 of the tool holder shank 91 when the engagement member 20 is in the above-described second position. When the tension rod 5 is in the forward release position, as shown in FIGS. 4 and 16, the front end of the engagement member 20 is located behind the head portion 6 of the tension rod 5, and the engagement flange 27 is disengaged from the engagement with the engagement groove 94 of the tool holder shank 91. When the tension rod 5 moves axially rearward along its longitudinal axis L within the bore 3, the inclined surface 8 of the head portion 6 of the tension rod contacts the front end of the engagement member 20, and the front end of the engagement member 20 slides on the inclined surface 8 and is pressed outward, whereby the engagement flange 27 of the engagement member engages with the engagement groove 94 of the tool holder shank 91. Thereafter, the tool holder shank 91 is pulled by the tension rod 5 and firmly contacts the inner surface of the housing 2 at the above-described attachment portion 10.

[0032] The clamping device 1 further includes an actuating member 14. The actuating member 14 is rotatably disposed within the bore 3 so as to be rotatable with respect to the tension rod 5 and the housing 2 about the longitudinal axis L, and is axially fixed to the housing 2 so as to be prevented from moving with respect to the housing 2 along the longitudinal axis L. The actuating member 14 is concentric with the tension rod 5.

[0033] The motion transmission mechanism is disposed inside the housing 2 and is configured to transmit the rotational movement of the actuating member 14 in the first rotational direction D1 with respect to the housing 2 to the axial movement of the tension rod 5 from the forward release position to the rearward lock position. This motion transmission mechanism includes - a first motion transmission element 40 fixed to or fixedly connected to the tension rod 5 so as to be movable along the longitudinal axis L together with the tension rod, and provided with a first pressure-receiving contact surface 41 facing the front end portion 2a of the housing; - a second motion transmission element 50 fixed to the actuating member 14 so as to be rotatable with respect to the housing 2 and the tension rod 5 together with the actuating member, and provided with a first pressing contact surface 51 facing the rear end portion 2b of the housing for contacting the first pressure-receiving contact surface 41 and is provided with.

[0034] The first pressing contact surface 51 is configured to press the tension rod 5 from the forward release position to the retracted lock position by sliding and pressing against the first pressure-receiving contact surface 41 when the actuating member 14 rotates in the first rotational direction D1.

[0035] The first pressure-receiving contact surface 41 includes a first contact surface section 41a and a second contact surface section 41b that are arranged at different positions along the first motion transmission element 40. The first pressure-applying contact surface 51 includes a first contact surface section 51a and a second contact surface section 51b that are arranged at different positions along the second motion transmission element 50. When the actuating member 14 moves in the first rotational direction D1, the first section 51a of the first pressure-applying contact surface 51 is configured to slide and press against the first section 41a of the first pressure-receiving contact surface 41 during the first stage of the movement, and the second section 51b of the first pressure-applying contact surface 51 is configured to slide and press against the second section 41b of the first pressure-receiving contact surface 41 during the final stage of the movement. The first section 41a of the first pressure-receiving contact surface 41 has a larger pitch than the second section 41b of the first pressure-receiving contact surface 41. Similarly, the first section 51a of the first pressure-applying contact surface 51 has a larger pitch than the second section 51b of the first pressure-applying contact surface 51. Thereby, the same angular displacement of the actuating member 14 associated with the rotation in the first rotational direction D1 with respect to the housing 2 results in a larger axial movement of the tension rod 5 along the longitudinal axis L in the first stage than in the final stage. The pitch of the first section 41a of the first pressure-receiving contact surface 41 is preferably about 5 to 8 times the pitch of the second section 41b of the first pressure-receiving contact surface 41, and the pitch of the first section 51a of the first pressure-applying contact surface 51 is preferably about 5 to 8 times the pitch of the second section 51b of the first pressure-applying contact surface 51.

[0036] The first section 51a of the first pressure-applying contact surface 51 preferably has the same pitch as the first section 41a of the first pressure-receiving contact surface 41. Similarly, the second section 51b of the first pressure-applying contact surface 51 preferably has the same pitch as the second section 41b of the first pressure-receiving contact surface 41.

[0037] In the illustrated embodiment, the pitch is constant along the first section 41a of the first pressure-receiving contact surface 41 and also constant along the second section 41b of the first pressure-receiving contact surface 41, but is smaller. In the illustrated embodiment, the pitch is also constant along the first section 51a of the first pressure-applying contact surface 51 and also constant along the second section 51b of the first pressure-applying contact surface 51, but is smaller. However, the pitch may alternatively vary along one or both of the above-described sections 41a, 41b of the first pressure-receiving contact surface 41 and along one or both of the above-described sections 51a, 51b of the first pressure-applying contact surface 51.

[0038] In the illustrated embodiment, the first and second sections 41a, 41b of the first pressure-receiving contact surface 41 are positioned adjacent to each other on the first motion transmission element 40 such that the second section 41b follows immediately after the first section 41a. Similarly, the first and second sections 51a, 51b of the first pressure-applying contact surface 51 are positioned adjacent to each other on the second motion transmission element 50 such that the second section 51b follows immediately after the first section 51a. However, alternatively, the first pressure-receiving contact surface 41 may include an intermediate section positioned on the first motion transmission element 40 between the first section 41a and the second section 41b of the first pressure-receiving contact surface 41. Similarly, the first pressure-applying contact surface 51 may include an intermediate section positioned on the second motion transmission element 50 between the first section 51a and the second section 51b of the first pressure-applying contact surface 51.

[0039] According to the illustrated embodiment, the motion transmission mechanism is also configured to transmit the rotational movement of the actuating member 14 in a second rotational direction D2 opposite to the first rotational direction D1 with respect to the housing 2 to the axial movement of the tension rod 5 from the retracted lock position to the advanced release position. For this purpose, the first motion transmission element 40 is provided with a second pressure-receiving contact surface 42, and the second pressure-receiving contact surface 42 faces the rear end portion 2b of the housing and is configured to cooperate with a second pressure-applying contact surface 62 provided on the third motion transmission element 60. This element 60 is fixed to the actuating member 14 so as to be rotatable with respect to the housing 2 and the tension rod 5 together with the actuating member. The second pressure-applying contact surface 62 faces the front end portion 2a of the housing in order to contact the second pressure-receiving contact surface 42, and the second pressure-applying contact surface 62 is configured to press the tension rod 5 from the retracted lock position to the advanced release position by sliding and pressing against the second pressure-receiving contact surface 42 when the actuating member 14 rotates with respect to the housing 2 in the second rotational direction D2.

[0040] The second pressure-receiving contact surface 42 may include a first contact surface section 42a and a second contact surface section 42b arranged at different positions along the first motion transmission element 40. Similarly, the second pressure-applying contact surface 62 may include a first contact surface section 62a and a second contact surface section 62b arranged at different positions along the third motion transmission element 60. When the actuating member 14 moves in the second rotation direction D2, the first section 62a of the second pressure-applying contact surface 62 is configured to slide and press against the first section 42a of the second pressure-receiving contact surface 42 during the first stage of this movement, and the second section 62b of the second pressure-applying contact surface 62 is configured to slide and press against the second section 42b of the second pressure-receiving contact surface 42 during the final stage of this movement. The first section 42a of the second pressure-receiving contact surface 42 has a smaller pitch than the second section 42b of the second pressure-receiving contact surface 42. Similarly, the pitch of the first section 62a of the first pressure-applying contact surface 62 is smaller than the pitch of the second section 62b of the first pressure-applying contact surface 62. Thereby, the same angular displacement of the actuating member 14 associated with the rotation of the second rotation direction D2 with respect to the housing 2 results in an axial movement of the tension rod 5 along the longitudinal axis L that is greater in the final stage of this rotational movement than in the first stage of this rotational movement. The pitch of the second section 42b of the second pressure-receiving contact surface 42 is preferably about 5 to 8 times the pitch of the first section 42b of the second pressure-receiving contact surface 42, and the pitch of the second section 62b of the second pressure-applying contact surface 62 is preferably about 5 to 8 times the pitch of the first section 62a of the second pressure-applying contact surface 62.

[0041] The first section 62a of the second pressure-applying contact surface 62 preferably has the same pitch as the first section 42a of the second pressure-receiving contact surface 42. Similarly, the second section 62b of the second pressure-applying contact surface 62 preferably has the same pitch as the second section 42b of the second pressure-receiving contact surface 42.

[0042] In the illustrated embodiment, the pitch is constant along the first section 42a of the second pressure-receiving contact surface 42 and is also constant along the second section 42b of the second pressure-receiving contact surface 42, but is larger. In the illustrated embodiment, the pitch is also constant along the first section 62a of the second pressure-applying contact surface 62 and is also constant along the second section 62b of the second pressure-applying contact surface 62, but is larger. However, the pitch may alternatively vary along one or both of the above-described sections 42a, 42b of the second pressure-receiving contact surface 42 and along one or both of the above-described sections 62a, 62b of the second pressure-applying contact surface 62.

[0043] In the illustrated embodiment, the first and second sections 42a, 42b of the second pressure-receiving contact surface 42 are positioned adjacent to each other on the first motion transmission element 40 such that the second section 42b follows immediately after the first section 42a. Similarly, the first and second sections 62a, 62b of the second pressure-applying contact surface 62 are positioned adjacent to each other on the third motion transmission element 60 such that the second section 62b follows immediately after the first section 62a. However, alternatively, the second pressure-receiving contact surface 42 may include an intermediate section positioned on the first motion transmission element 40 between the first section 42a and the second section 42b of the second pressure-receiving contact surface 42. Similarly, the second pressure-applying contact surface 62 may include an intermediate section positioned on the third motion transmission element 60 between the first section 62a and the second section 62b of the second pressure-applying contact surface 62.

[0044] The first motion transmission element 40 is received in the gap between the second motion transmission element 50 and the third motion transmission element 60. Accordingly, the second and third motion transmission elements 50, 60 are disposed on both sides of the first motion transmission element 40 when viewed in the axial direction of the actuating member 14.

[0045] The motion transmission elements 40, 50, 60 of the above type may be arranged in two or more sets, and each set includes a first motion transmission element 40 and associated second and third motion transmission elements 50, 60. These sets are circumferentially spaced apart from each other with respect to the actuating member 14. In the illustrated embodiment, the motion transmission mechanism of the clamping device 1 includes two such sets of motion transmission elements.

[0046] In the illustrated embodiment, the motion transmission elements 40, 50, 60 form part of two screw threads that are arranged in screw engagement with each other. In this case, the first and second pressure receiving contact surfaces 41, 42 and the first and second pressure applying contact surfaces 51, 62 have the form of screw surfaces. Alternatively, each of the first and second pressure applying contact surfaces 51, 62 may have the form of a relatively short convex surface arranged on a pin-like shaped motion transmission element, and the first and second pressure receiving contact surfaces 41, 42 may act as cam surfaces for the first and second pressure applying contact surfaces. In the latter case, only the first and second pressure receiving contact surfaces 41, 42 are divided into the first and second contact surface sections 41a, 41b, 42a, 42b as described above.

[0047] As a further alternative, each of the first and second pressure receiving contact surfaces 41, 42 may have the form of a relatively short convex surface arranged on a pin-like shaped first motion transmission element, and the first and second pressure applying contact surfaces 51, 62 may act as cam surfaces for the first and second pressure receiving contact surfaces. In the latter case, only the first and second pressure applying contact surfaces 51, 62 are divided into the first and second contact surface sections 51a, 51b, 62a, 62b as described above.

[0048] The second contact surface section 41b of the first pressure-receiving contact surface 41 and / or the second contact surface section 51b of the first pressure-applying contact surface 51 preferably has a pitch such that when the tension rod is pushed into the retracted lock position under the action of the actuating member 14 and the first and second movement transmission elements 40, 50, the first and second movement transmission elements 40, 50 keep the actuating member 14 in the self-locking rotation position with respect to the tension rod 5. In the self-locking rotation position, the frictional force between the first pressure-applying contact surface 51 and the first pressure-receiving contact surface 41 prevents the actuating member 14 from rotating in the second rotation direction D2 described above.

[0049] In the illustrated embodiment, the first and second pressure-receiving contact surfaces 41, 42 are provided on the outside of the shafts 15, 15', which are fixed to the tension rod 5 and configured to move along the longitudinal axis L together with the tension rod. The tension rod 5 and the shaft 15 may be integrally formed as shown in FIGS. 1 and 4. However, the shaft 15' may alternatively be formed as a separate component fixed to the tension rod 5 via a screw joint formed by, for example, the female thread 16a of the shaft 15' and the corresponding male thread 16b of the tension rod 5 as shown in FIGS. 14 and 16. However, the shaft 15' may of course be fixed to the tension rod 5 by any other suitable method. In the illustrated example, each of the first movement transmission elements 40 has the form of an external protrusion on the enveloping surface of the shafts 15, 15'.

[0050] In the illustrated embodiment, the actuating member 14 is in the form of a sleeve that surrounds the shafts 15, 15', where the first and second pressure-applying contact surfaces 51, 62 are provided inside the actuating member. To facilitate the assembly of the clamping device 1, the sleeve-shaped actuating member 14 is suitably formed by two separate sleeve sectors 14a, 14b that are joined to form the sleeve and clamped to each other by a clamping ring 17. In the illustrated example, each of the second and third movement transmission elements 50, 60 has the form of an internal protrusion inside the actuating member 14.

[0051] In the illustrated embodiment, the actuating member 14 and the second and third motion transmission elements 50, 60 together form a nut configured to cooperate with a screw formed by the shafts 15, 15' and the first motion transmission element 40.

[0052] Alternatively, the actuating member 14 may have the form of a shaft, and the first and second pressure contact surfaces 51, 62 are provided on the outside of the actuating member. In this case, the first and second pressure receiving contact surfaces 41, 42 are provided inside a sleeve, and the sleeve surrounds the shaft-shaped actuating member, is fixed to the tension rod 5, and is configured to move along the longitudinal axis L together with the tension rod. The tension rod 5 and this sleeve may be integrally formed. However, the sleeve may alternatively be formed as a separate component fixed to the tension rod 5, for example, via a screw joint.

[0053] The tension rod 5 is prevented from rotating relative to the housing 2. In the embodiments shown in FIGS. 1 to 11, the tension rod 5 is provided with several stop lugs 30 that project radially from the peripheral wall of the tension rod and are distributed around the central axis of the tension rod. These stop lugs 30 are slidably received in respective longitudinal grooves 31 on the wall surface in the bore 3 to prevent relative rotation between the tension rod 5 and the housing 2. In the embodiments shown in FIGS. 12 to 23, an elongated stop member 32 extends through an aperture 33 in a plate 34 non-rotatably mounted inside the housing 2, and this stop member 32 is slidably received in an axially extending recess 35 in the shaft 15' to prevent relative rotation between the tension rod 5 and the housing 2. Of course, relative rotation between the tension rod 5 and the housing 2 may also be prevented by any other suitable method.

[0054] The clamping device 1 may also include one or more additional components such as one or more hydraulic, pneumatic, or electric actuators for rotating the actuating member 14 in the first and second rotational directions D1, D2. The control of the clamping device 1 may be automated by such an actuator. Thus, the clamping device 1 according to the present invention is suitable for use in an automatic tool change operation. However, the clamping device 1 according to the present invention may also be adapted for manual operation.

[0055] In the illustrated embodiment, the clamping device 1 includes hydraulic actuators 70, 70' that are disposed within or attached to the housing 2 and configured to rotate the actuating member 14 relative to the housing 2. In the illustrated embodiment, the hydraulic actuators 70, 70' are integrated with the housing 2 of the clamping device. However, the hydraulic actuators 70, 70' may alternatively include a separate actuator casing fixed to the housing of the clamping device.

[0056] In the embodiments shown in FIGS. 1 to 11, the hydraulic actuator 70 includes a rotatable actuator shaft 71 whose rotation axis is arranged in alignment with the rotation axis of the actuating member 14. The actuating member 14 is configured to be rotatable with respect to the housing 2 together with the actuator shaft 71 in the above-described first and second rotational directions D1, D2. The hydraulic actuator 70 also includes two actuator vanes 72, and the two actuator vanes 72 are fixed to the actuator shaft 71 and are configured to be rotatable together with the actuator shaft 71 about the rotation axis of the actuator shaft. The actuator vane 72 projects in a direction opposite to the radial direction from the actuator shaft 71. The actuator vane 72 and the actuator shaft 71 are preferably integrally formed. Each actuator vane 72 is movably received in the internal space 73 of the hydraulic actuator 70, and the internal space 73 is configured to be divided into a first hydraulic chamber 74a on the first side of the actuator vane and a second hydraulic chamber 74b on the opposite second side of the actuator vane. For example, hydraulic fluid in the form of hydraulic oil may be supplied to and discharged from the first hydraulic chamber 74a via a first inlet and outlet port 75a, respectively, and may be supplied to and discharged from the second hydraulic chamber 74b via a second inlet and outlet port 75b, respectively. The actuating member 14 is rotatable in the first rotational direction D1 by the supply of hydraulic fluid to the first hydraulic chamber 74a and is rotatable in the second rotational direction D2 by the supply of hydraulic fluid to the second hydraulic chamber 74b, together with the actuator shaft 71 and the actuator vanes 72.

[0057] In the embodiments shown in FIGS. 1 to 11, the hydraulic actuator 70 includes a cylindrical cavity 76 that is radially outwardly restricted by the cylindrical wall 77 of the housing 2, and the above-described internal space 73 forms part of this cylindrical cavity 76. The actuator shaft 71 is rotatably disposed within the cylindrical cavity 76, and its longitudinal axis coincides with the central axis of the cylindrical cavity. The longitudinal outer edge portion 72a of each actuator vane 72 contacts the cylindrical wall 77. If desired, an elongated seal member may be disposed along the longitudinal outer edge portion 72a of each actuator vane 72 to form a liquid-tight seal at the interface between the actuator vane 72 and the cylindrical wall 77, thereby preventing hydraulic fluid from leaking from one hydraulic chamber to the other through this interface. However, since a slight leakage of hydraulic fluid between the hydraulic chambers 74a, 74b that does not impair the functionality of the hydraulic actuator 70 can be tolerated, such a seal member is unnecessary.

[0058] Each of the above-described internal spaces 73 extends circumferentially of the cylindrical cavity 76 between the first and second chamber walls 78a, 78b, and the first and second chamber walls 78a, 78b are disposed inside the cylindrical cavity 76 and extend longitudinally along the hydraulic chambers 74a, 74b. The first chamber wall 78a faces the first hydraulic chamber 74a and is configured to limit this hydraulic chamber 74a in the circumferential direction of the cylindrical cavity 76. The second chamber wall 78b faces the second hydraulic chamber 74b and is configured to limit this hydraulic chamber 74b in the circumferential direction of the cylindrical cavity 76. As shown in FIG. 6, the actuator vane 72 is configured to contact the first chamber wall 78a when the tension rod 5 reaches the forward release position, thereby preventing further movement of the tension rod 5 toward the front end portion 2a of the housing 2.

[0059] The exact axial position of the tension rod 5 within the bore 3 depends on the tolerances of the tool holder shank 91 and the mounting part 10, and thus it is impossible to predict the exact final position of the actuator vane 72 in the first rotational direction D1. Therefore, the actuator vane 72 cannot be configured to reach the second chamber wall 78b when the tension rod 5 takes its retracted lock position. As a result, each actuator vane 72 is configured to take a position somewhere between the associated first chamber wall 78a and the second chamber wall 78b when the tension rod 5 reaches the retracted lock position, as shown in FIG. 3.

[0060] The first and second chamber walls 78a, 78b are preferably configured to form part of an elongated partition element 79, preferably in the form of a solid body, which is mounted inside the cylindrical cavity 76 and extends along its longitudinal direction along the cylindrical cavity 76. These partition elements 79 are fixed to the cylindrical wall 77, for example, by screws 80.

[0061] In the embodiment shown in FIGS. 1 to 11, the internal space 73 described above is limited in the first axial direction by the rear end wall 14c on the actuating member 14 and in the opposite axial direction by an end piece 81 fixed to the housing 2 at its rear end 2b.

[0062] In the embodiment shown in FIGS. 1 to 11, the end portion 72b at the front end of each actuator vane 72 is received in a radially extending recess in the rear end wall 14c of the actuating member 14, enabling the transmission of torque from the actuator vane 72 to the actuating member 14 and preventing the actuating member from rotating relative to the actuator vane 72 and the actuator shaft 71. However, the actuating member 14 may of course be non-rotatably connected to the actuator vane 72 and / or the actuator shaft 71 in any other suitable manner.

[0063] In the embodiments shown in FIGS. 1 to 11, the hydraulic actuator 70 includes two actuator vanes 72. However, the hydraulic actuator may alternatively include more than two actuator vanes 72 evenly distributed around the actuator shaft 71 and received in respective internal spaces of the hydraulic actuator, or a single actuator vane 72.

[0064] In the embodiments shown in FIGS. 12 to 23, the hydraulic actuator 70' includes an actuator vane 72', the actuator vane 72' is fixed to the actuating member 14, and is configured to be rotatable with the actuating member 14 relative to the housing 2. The actuator vane 72' projects radially from the actuating member 14. The actuator vane 72' and one of the sleeve sectors 14a of the actuating member 14 are preferably integrally formed. The actuator vane 72' is movably received in the internal space 73' of the hydraulic actuator, and this internal space 73' is configured to be divided into a first hydraulic chamber 74a' on the first side of the actuator vane and a second hydraulic chamber 74b' on the opposite second side of the actuator vane. For example, hydraulic fluid in the form of hydraulic oil may be supplied to and discharged from the first hydraulic chamber 74a' via the first inlet and outlet ports 75a', and supplied to and discharged from the second hydraulic chamber 74b' via the second inlet and outlet ports 75b'. The actuating member 14, together with the actuator vane 72', is rotatable in a first rotational direction D1 by the supply of hydraulic fluid to the first hydraulic chamber 74a', and rotatable in a second rotational direction D2 by the supply of hydraulic fluid to the second hydraulic chamber 74b'.

[0065] When viewed in the rotational direction of the actuator vane 72', the first chamber wall 78a' is disposed at the first end of the internal space 73', the second chamber wall 78b' is disposed at the second end on the opposite side of the internal space 73', the first chamber wall 78a' faces the first hydraulic chamber 74a', and the second chamber wall 78b' faces the second hydraulic chamber 74b'. As shown in FIG. 16, the actuator vane 72' is configured to contact the first chamber wall 78a' when the tension rod 5 reaches the forward release position, thereby preventing further movement of the tension rod 5 toward the front end 2a of the housing 2. As shown in FIG. 14, the actuator vane 72' is configured to take a position somewhere between the first chamber wall 78a' and the second chamber wall 78b' when the tension rod 5 reaches the retracted lock position.

[0066] In the embodiment shown in FIGS. 12 to 23, the housing 2 includes an insertion piece 82 that is attached to the above-described base portion 12 of the housing via an aperture 83 (see FIG. 19) in the outer wall of the base portion. The insertion piece 82 includes two legs 84, and an essentially U-shaped seat 85 for the actuating member 14 is formed between these legs. The actuating member 14 is rotatably received in this seat 85. The actuator vane 72' extends through an opening provided between the free ends of the legs 84. The above-described first chamber wall 78a' is formed by the surface of the free end of one leg 84, and the second chamber wall 78b' is formed by the surface of the free end of the other leg 84.

[0067] When the tool holder 90 is clamped to the housing 2, as shown in FIGS. 4 and 16, with the tension rod 5 positioned in the forward release position, the tool holder shank 91 is inserted into the mounting portion 10 of the bore 3. Thereby, the head portion 6 of the tension rod is received within the engagement bore 92 of the tool holder shank 91, and the engagement groove 94 of the tool holder shank 91 is positioned outside the engagement flange 27 of the engagement member 20. As a result, hydraulic fluid is supplied to the first hydraulic chamber 74a' or chamber 74a to rotate the actuator shaft 14 in the first rotational direction D1. During this first stage of the rotational movement of the actuating member 14, the first section 51a of the first pressure contact surface 51 slides and presses against the first section 41a of the first pressure receiving contact surface 41. Thereby, the tension rod 5 is axially displaced rearward within the bore 3 toward the rear lock position. The relatively large pitch of the sections 41a, 51a results in a relatively rapid displacement of the tension rod 5. Since the initial displacement of the tension rod 5 does not require a large force, a relatively large pitch is advantageous. The first and second sections 51a, 51b of the first pressure contact surface 51 and the first and second sections 41a, 41b of the first pressure receiving contact surface 41 are arranged such that when the actuating member 14 undergoes an angular displacement such that the first section 51a of the first pressure contact surface 51 passes the first section 41a of the first pressure receiving contact surface 41 and the second section 51b of the first pressure contact surface 51 reaches the second portion 41b of the first pressure receiving contact surface 41, i.e., during the transition between these respective sections, the tension rod 5 reaches approximately its final rearward position within the bore 3. Thus, in the final clamping stage where a large force is beneficial, the second sections 51b, 41b of the first pressure and pressure receiving contact surfaces 41, 51 are active. At this stage, the relatively large angular displacement of the actuating member 14 results in a very small axial displacement of the tension rod 5, which results in a force amplification effect that enables the tension rod 5 to pull the tool holder shank 91 with a large force and engage firmly with the housing 2. Further, the small pitch of the second sections 51b, 41b of the first pressure and pressure receiving contact surfaces 51, 41 provides a self-locking effect, ensuring that the clamping device 1 remains in the clamped state without any additional locking means.Thereby, the force to the actuating member 14 may be released when the tension rod 5 reaches the retracted lock position.

[0068] When a tool change operation is performed and the tool holder 90 is released from the housing 2, the hydraulic fluid is supplied to the second hydraulic chamber 74b' or the chamber 74b to rotate the actuator member 14 in the second rotational direction D2. When the actuating member 14 receives sufficient force in the second rotational direction D2, the self-locking frictional engagement between the second sections 51b, 41b of the first pressure and pressure receiving contact surfaces 51, 41 is released, and then the actuating sleeve 14 becomes rotatable in the second rotational direction D2 with respect to the housing 2 to axially push the tension rod 5 forward in the bore 3 toward the forward release position. During the first stage of this rotational movement of the actuating member 14, the first section 62a of the second pressure contact surface 62 slides and presses against the first section 42a of the second pressure receiving contact surface 42, and then the second section 62b of the second pressure contact surface 62 slides and presses against the second section 42b of the second pressure receiving contact surface 42 during the subsequent final stage of this rotational movement of the actuating member 14. When the tension rod 5 moves toward the forward release position, the outer end of the head portion 6 of the tension rod 5 collides with the surface 95 in the engagement bore 92 of the tool holder shank 91, thereby releasing the tool holder shank 91 from the housing 2.

[0069] Naturally, the present invention is not limited to the above-described embodiments at all. Rather, many possibilities for its modification will be apparent to those skilled in the art without departing from the basic concept of the present invention as defined in the appended claims.

Claims

1. A clamping device for releasably holding a tool holder shank, wherein the clamping device (1) comprises: - A housing (2) having a front end portion (2a), a rear end portion (2b), and a bore (3) intersecting the front end portion and extending rearward from the front end portion, wherein a mounting portion (10) for receiving the tool holder shank (91) is provided at the front end portion of the bore (3); a housing (2); - A tension rod (5) slidably mounted inside the bore (3) so as to be reciprocally movable within the bore along its longitudinal axis (L) between a forward release position and a rearward lock position; - An engaging member (20) disposed around the front end portion of the tension rod (5) and around the tension rod (5), wherein the engaging member (20) is configured such that, under the influence of the tension rod (5) moving from the forward release position to the rearward lock position, the tool holder shank (91) can enter and exit the mounting portion (10) of the bore (3) by the engaging member (20). From a first position, the engaging member (20) is lock-engaged with the tool holder shank (91) and is movable to a second position where the tool holder shank (91) is fixed to the housing (2); an engaging member (20); comprising; - The clamping device (1) comprises an actuating member (14) rotatably disposed within the bore (3) so as to be rotatable about the longitudinal axis (L), wherein the actuating member (14) is axially fixed relative to the housing (2), thereby preventing it from moving along the longitudinal axis (L); - The clamping device (1) comprises a motion transmission mechanism disposed inside the housing (2), and the motion transmission mechanism is configured to transmit a rotational movement of the actuating member (14) in a first rotational direction (D1) relative to the housing (2) to an axial movement of the tension rod (5) from the forward release position to the rearward lock position; - The motion transmission mechanism is · A first motion transmission element (40) fixed to or fixedly connected to the tension rod (5) so as to be movable along the longitudinal axis (L) together with the tension rod, and having a first pressure-receiving contact surface (41) facing the front end portion (2a) of the housing; - A second motion transmission element (50) fixed to the actuating member (14) so as to be rotatable with respect to the housing (2) and the tension rod (5) together with the actuating member, and having a first pressure contact surface (51) facing the rear end portion (2b) of the housing for contacting the first pressure receiving contact surface (41), wherein the first pressure contact surface (51) is configured to press the tension rod (5) from the forward release position to the rearward lock position by sliding and pressing against the first pressure receiving contact surface (41) when the actuating member (14) rotates in the first rotation direction (D1). The second motion transmission element (50). Comprising; - At least one of the contact surfaces (41, 51) comprises a first contact surface section (41a, 51a) and a second contact surface section (41b, 51b) arranged at different positions along the associated motion transmission element (40, 50), whereby when the actuating member (14) moves in the first rotation direction (D1), the first contact surface section (41a, 51a) is configured to slide against the other contact surface (51, 41) during the first stage of the movement, and the second contact surface section (41b, 51b) is configured to slide against the other contact surface (51, 41) during the final stage of the movement, and the first contact surface section (41a, 51a) has a larger pitch than the second contact surface section (41b, 51b), whereby the same angular displacement of the actuating member (14) associated with the rotation of the housing (2) in the first rotation direction (D1) results in a larger axial movement of the tension rod (5) in the first stage than in the final stage. A clamping device, characterized in that.

2. The clamping device according to claim 1, characterized in that the pitch is constant along the second contact surface section (41b, 51b).

3. The clamping device according to claim 1 or claim 2, characterized in that the pitch is constant along the first contact surface section (41a, 51a).

4. The second contact surface section (41b, 51b) is positioned adjacent to the first contact surface section (41a, 51a) on the associated motion transmission element (40, 50) such that the second contact surface section (41b, 51b) follows immediately after the first contact surface section (41a, 51a). The clamping device according to claim 3, characterized in that.

5. When the tension rod is pushed into the retracted lock position under the influence of the actuating member (14) and the first and second motion transmission elements (40, 50), the second contact surface section (41b, 51b) is such that the first and second motion transmission elements (40, 50) keep the actuating member (14) in a self-locking rotational position with respect to the tension rod (5). The clamping device according to any one of claims 1 to 4, characterized in that it has a pitch.

6. The first pressure-receiving contact surface (41) comprises the first and second contact surface sections (41a, 41b). The clamping device according to any one of claims 1 to 5, characterized in that.

7. The first pressure-applying contact surface (51) comprises the first and second contact surface sections (51a, 51b). The clamping device according to any one of claims 1 to 6, characterized in that.

8. The first contact surface section (51a) of the first pressure-applying contact surface (51) is configured to slide and press against the first contact surface section (41a) of the first pressure-receiving contact surface (41) during the first stage of the rotational movement of the actuating member (14) in the first rotational direction (D1). The second contact surface section (51b) of the first pressure-applying contact surface (51) is configured to slide and press against the second contact surface section (41b) of the first pressure-receiving contact surface (41) during the final stage of this rotational movement. The clamping device according to claim 7 in combination with claim 6, characterized in that.

9. - The first contact surface section (51a) of the first pressure-applying contact surface (51) has the same pitch as the first contact surface section (41a) of the first pressure-receiving contact surface (41); - The second contact surface section (51b) of the first pressure-applying contact surface (51) has the same pitch as the second contact surface section (41b) of the first pressure-receiving contact surface (41). The clamping device according to claim 8, characterized in that.

10. The first and second motion transmission elements (40, 50) form part of two threads that are screw-engaged with each other, and the contact surfaces (41, 51) have the form of screw surfaces. The clamping device according to any one of claims 1 to 9, characterized in that.

11. - The first motion transmission element (40) has the form of an external protrusion on the enveloping surface of a shaft (15, 15') fixed to the tension rod (5); - The actuating member (14) is in the shape of a sleeve, surrounds the shaft (15, 15'), and the second motion transmission element (50) has the form of an internal protrusion on the actuating member (14); The clamping device according to any one of claims 1 to 10, characterized in that.

12. The motion transmission mechanism is configured to transmit the rotational movement of the actuating member (14) in a second rotational direction (D2) opposite to the first rotational direction (D1) to the axial movement of the tension rod (5) from the retracted locking position to the advanced release position. The clamping device according to any one of claims 1 to 11, characterized in that.

13. - The first motion transmission element (40) is provided with a second pressure-receiving contact surface (42) facing the rear end portion (2b) of the housing; - The motion transmission mechanism is fixed to the actuating member (14) so as to be rotatable with respect to the housing (2) together with the actuating member, and includes a third motion transmission element (60) provided with a second pressure-applying contact surface (62) facing the front end portion (2a) of the housing for contacting the second pressure-receiving contact surface (42). The second pressure-applying contact surface (62) is configured to press the tension rod (5) from the retracted locking position to the advanced release position by sliding and pressing against the second pressure-receiving contact surface (42) when the actuating member (14) rotates in the second rotational direction (D2); The clamping device according to claim 12, characterized in that.

14. The second pressure-receiving contact surface (42) includes a first contact surface section (42a) and a second contact surface section (42b) arranged at different positions along the first motion transmission element (40). Thereby, when the actuating member (14) moves in the second rotational direction (D2), the second pressure-applying contact surface (62) slides and presses against the first contact surface section (42a) of the second pressure-receiving contact surface (42) during a first stage of this movement and against the second contact surface section (42b) of the second pressure-receiving contact surface (42) during a final stage of this movement. The first contact surface section (42a) of the second pressure-receiving contact surface (42) has a smaller pitch than the second contact surface section (42b) of the second pressure-receiving contact surface (42). Thereby, the same angular displacement associated with the rotation of the actuating member (14) in the second rotational direction (D2) relative to the housing (2) results in a greater axial movement of the tension rod (5) in the final stage of this rotational movement than in the first stage of this rotational movement. The clamping device according to claim 13, characterized in that.

15. The motion transmission mechanism includes two or more sets of the motion transmission elements. Each set includes a first motion transmission element (40) and an associated second motion transmission element (50). These sets are spaced apart from each other in the circumferential direction of the actuating member (14). The clamping device according to any one of claims 1 to 14, characterized in that.

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