Patent ID: 12202095

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In the different figures of this invention and its part, like details are indicated by like reference numbers throughout the figures and its specification. The reference number1indicates a clamping device according to the invention in its entirety.

FIG.1shows a schematic side view of a clamping device1designed as a part of a grinding machine, in particular comprising a cup-shaped grinding wheel to machine a workpiece10, such as a cutting tool clamped in the clamping device1. A rotary plate2on a machine bed can be moved in a direction of a first rotational axis, identified as a C-axis (not shown). Furthermore, the clamping device1can be pivoted about a B-axis18. Thanks to a pivoting movement by rotating the clamping device1about a A-axis (not shown), perpendicular to the B-axis18and thanks to translational and/or rotational movements of the grinding wheel about at least the X-axis and an Y-axis (not shown) the peripheral surface of the clamped workpiece10can be theoretically ground. The rotary plate2of the grinding machine bears a workpiece spindle headstock comprising inter alia the clamping device1.

The workpiece10, such as a cutting tool, in particular an indexable insert to be ground can be affixed to, centered and securely clamped on the clamping device1, in particular between a clamping anvil12and a drive anvil14. The clamping anvil12is supported in a clamping device holding element22of a clamping unit20and movable in translation along a clamping axis, identified as16to apply a clamping force. The drive anvil14is supported in a drive unit30and is connectable to a drive axis, the B-axis18, of the grinding machine. Thus, during grinding the workpiece10can be rotated about the B-axis18.

Not shown inFIG.1, arranged at a distance from the rotary plate2does a grinding spindle headstock comprise inter alia a cup-shaped grinding wheel, wherein the grinding spindle headstock can be pivoted and moved relative to the rotary plate2. Therefore, in the grinding machine for performing grinding of the workpiece10a plurality of controlled movements are mutually coordinated with one another.

According to a first embodiment of the clamping unit1, the workpiece spindle headstock comprises the drive unit30and a support unit40, which are not shown in further details. According to theFIG.1, the support unit40is designed in L-shape with one portion, protruding substantially perpendicular from a support plate39and identified as a first leg42. In the first leg42, a bore is provided, configured as a bearing bore, such that an axis of the bore is aligned coaxially with the clamping axis16and extend parallel to a longitudinal extension of the support plate39. In the bore of the first leg42, the drive unit30is rotatably mounted consisting of the drive anvil14, comprising a drive shaft32and an interchangeable drive pin34. The drive shaft32can be inserted with a drive cone into a receiving cone of the B-axis18, wherein the B-axis18can be rigidly supported by a B-axis bearing of the drive holding element30to provide very exact concentricity. The workpiece10can be fixedly mounted on the drive pin34by connection means.

According to the first embodiment, shown inFIG.1as a counterpart of the drive anvil14the clamping anvil12is provided, supported in the clamping unit20such that it is guided free of play axially and rotationally freely movable. The workpiece10, in particular the indexable insert can be clamped between the drive anvil14and the clamping anvil12by arranging the workpiece10centered on the B-axis18and the clamping anvil12is moved by force against the drive anvil14, arranged as a counter ram. According to the first embodiment, the clamping unit20is a separate or individual part, which can be releasably or slidably attached the support unit40to form the workpiece spindle headstock of the grinding machine. The clamping unit20is mounted to the support unit40in such a manner, that the axis of the clamping anvil12and the drive anvil14are aligned to each other and aligned with the clamping axis16. For this purpose, the support unit40can provide on a contact surface50with positioning means60(not shown inFIG.1).

The clamping force provided by the clamping unit20can be introduced in various manner, for example can be carried out by an actuating device (not shown inFIG.1). The actuating device can comprise a power source, like a pneumatic or hydraulic cylinder unit, such that the movement of an actuating rod is transmitted via transmission means to the clamping device1, in particular to the clamping anvil12. Further details of the transmission means will be described later.

Furthermore, to provide sealing of the clamping unit20towards the environment a cover element70is releasably attached to the clamping unit20. Depending on the design and/or material of the cover element70, the attachable cover element70can contribute to increase the stiffness of the clamping unit20and finally of the clamping device1.

InFIG.2, a sectional schematic view of the clamping device1of the first embodiment is shown. As shown the drive anvil14and the clamping anvil12can be designed as being interchangeable. InFIG.2the clamping anvil12as well as the clamping unit20and the drive anvil14are designed in a so-called short version. With this short version, the space between the clamping unit20and the drive unit30is small such that the construction of the clamping device1is compact and stiff. With this design of the clamping device1, the grinding machine offers an increased stiffness and is in particular suitable to perform high-speed grinding operations on the workpiece10clamped by the clamping unit1. Also illustrated inFIG.2, a guide pin44is received by a guide bush45. The guide bush45is shown to be formed as roll bodies held in a cage47, wherein the roll bodies can be balls, rollers or sliders.

Furthermore, for applying a clamping force transmission means are provided inter alia comprising a lever unit100, described in further detail according toFIG.5.

FIG.3shows a perspective view of the clamping device1according to the first embodiment, wherein elements such as the support unit40and the clamping unit20as well as the cover element70are shown separated to one another. The support unit40is formed in L-shape with the first leg42to support the drive unit30. According to the first embodiment of the clamping device1, the clamping unit20is provided as an individual element such that the workpiece spindle headstock can be described as an assembly or a mounted group. The clamping unit20is supported in the clamping holding element22, wherein the clamping holding element22provides a contact surface24, which is orientated towards a supporting surface41of the support unit40. In order to position the releasable clamping unit20to the supporting surface41of the support unit40an interface43is provided with positioning means such as guide pins44protruding at predetermined positions from the interface43of the support unit40. The guide pins44led (i.e. received) in corresponding guide bushes45(not shown) provided on the contact surface24of the clamping unit20. This arrangement can be as well vice versa. The guide pins44can be formed as circularly cylindrical bodies. Further forms such as prism are as well possible. The guide bushes45can be formed by roll bodies, held in a cage, wherein the roll bodies can be balls, rollers or sliders. Furthermore, for fastening the clamping unit20to the support unit20, fastening means46can be provided.

The clamping unit1of the invention comprises measurement means to detect in particular the thickness of the workpiece10clamped in a secured manner between the clamping anvil12and the drive anvil14. Therefore, a measurement device80is provided comprising a measurement probe83, whereby the measuring means80are connectable with the clamping unit20, which in this embodiment is the releasably attached to the support unit40. The measuring means80comprise a measuring lever81and a measuring head82. The contact of the measuring lever81with the measuring head82or measuring probe can be configured in a prestressed manner by a spring element. For example, the contact between the measuring lever81and the measuring head82can be designed as between balls, between ball and plane, between rolls and/or roll and plane, etc. Furthermore, the measuring head82and the measuring probe83do not need direct contact for measuring but can be provided for optical measuring. Different materials are applicable for the elements in contact such as hardened steel, ceramic, sapphire or carbide.

InFIG.4, a schematic side view of the clamping device1according to a second embodiment is shown. The second embodiment of the clamping device1shows a so-called long version of it. In particular, the clamping unit20shows another design and the drive anvil14and/or the clamping anvil12protrude further out of their bearings such that a clearance between the drive unit30and the clamping unit20is larger than provided as in the short version according to the first embodiment. In this long version of the clamping device1, not only the drive anvil14and the clamping anvil12are designed with a long longitudinal extension but also the design of clamping unit20itself differs from that of the short version. In other words, the free space on both sides of the clamped workpiece10is increased for its positioning towards the cup-shaped grinding wheel. To provide stiffness to the configuration in this long version the clamping unit20differs from the short version of the clamping unit20according toFIGS.1to3.

FIG.5shows a sectional view of the clamping device1according to the second embodiment. To transmit an actuating force of an actuating unit92such as an actuating cylinder unit, supported in the support unit40of the clamping device1, transmission means90are provided such that a clamping force can be provided by the clamping unit20for securely clamping the workpiece10between the clamping anvil12and the drive anvil14. The actuating unit92comprises an actuating rod (not shown in detail) which is axially displaceable, acted upon a spring force and which is connected to the clamping unit20via a lever device100. Alternatively, the actuating unit92can be configured as a double-acting cylinder. The lever device100comprises a first arm102and a second arm104releasably connected to the first arm. The first arm pivots around a shaft106, pivoted in a bearing member provided at the support unit40of the clamping device1. The second arm104is connectable to the clamping anvil12such that the clamping anvil12moves axially to the clamping axis as a response to the pivot movement of the first arm102and therefore as a response of the actuation of the actuating unit92. According to the design of the lever device, the first arm102is arranged such to remain in the support unit40and the second arm104is arranged such to be interchangeable. Due to this, the lever unit100can be adapted to the version of the clamping unit20, in particular to the short version of the clamping unit20ofFIGS.1to3or to the long version of the clamping unit20ofFIGS.4to6.

InFIG.6, a perspective view of the clamping device1according to the second embodiment, wherein elements such as the support unit40and the clamping unit20as well as the cover element70are shown separated to one another is shown. The clamping unit20provides the contact surface24for mounting the clamping unit20to the support unit40, in particular to the supporting surface41. Therefore, the supporting surface41and/or the contact surface24are provided with guide means50corresponding to each other. Furthermore, the interface43of the support unit40for positioning and mounting the clamping unit20is provided as already described in accordance withFIG.3.

FIG.7shows a partially exploded view of the clamping device1of a third embodiment. According to the third embodiment the drive unit30, the clamping unit20and the support unit40are provided as individual elements, which can be releasably mounted to each other. In this embodiment the support unit40can be provided with linear guide elements such that the drive unit30and/or the clamping unit20can be slidable towards each other in a direction parallel to the clamping axis16and can be securely fixed in a position adjusted to the clearance between the drive unit30and the clamping unit20necessary for grinding the workpiece10with a cup-shaped grinding wheel at every surface to be machined.

Although the present disclosure has been described with reference to particular means, materials and embodiments, one skilled in the art can easily ascertain from the foregoing description the essential characteristics of the present disclosure, while various changes and modifications may be made to adapt the various uses and characteristics as set forth in the following claims.