Patent Application
20160107242
The present invention relates to tool holder assemblies and, in particular, tool holder assemblies employing one or more dampening elements.
Rotational machining operations, such as milling, boring, reaming and deburring generally utilize a rotating spindle for interfacing with cutting tools having a variety of designs and geometries. In order to securely retain such tools, tool holders are often provided with adapters suitable for receiving a multiplicity of differently sized and/or shaped tool shanks. Tool adapters, for example, can be used to facilitate rapid replacement of differing tool shank geometries or sizes leading to cutting operation efficiencies. However, such configurations generally introduce metal-to-metal contact surfaces capable of generating undesirable wear and vibrations during cutting operations. Vibrations induced during a cutting operation can shorten tool life and/or reduce workpiece surface finish. Transfer of vibrational resonance into a tool holder can also, in certain cases, result in an unsecure coupling between the cutting tool and the tool holder.
Tool holder assemblies, therefore, must be capable of accurately and securely retaining a tool while minimizing detrimental effects of vibration and wear during a machining operation. Various mechanisms and configurations have been developed for securing cutting tools into tool holder assemblies, but such configurations present deficiencies in minimization of vibration, simplification of design and scalability of design. Tool holder design continues to evolve in response to the changing demands of rotational cutting, milling and boring applications, thereby calling for the development of new assemblies and associated methods of assembling tool holders.
In one aspect, tool holder assemblies are described herein comprising a tool holder body and a tool receiver defining a plurality of axial sleeves filled with dampening elements. For example, a tool holder assembly described herein defines a central longitudinal axis and comprises a tool holder body having a connector portion and a holder portion. The connector portion is structured to engage a rotary machine and the holder portion is disposed opposite the connector portion and has an inner diameter surface comprising a plurality of axial grooves. A tool holder assembly further comprises a tool receiver structured to receive at least a portion of a cutting tool, the tool receiver having an outer diameter surface comprising a plurality of axial grooves. The tool receiver is mounted in the holder portion so as to align the axial grooves of the inner and outer diameter surfaces and define axial sleeves filled with dampening elements.
In another aspect, methods of assembling a tool holder having a central longitudinal axis are described herein. A method described herein comprises providing a tool holder body having a connector portion and a holder portion. The connector portion is structured to engage a rotary machine and the holder portion is disposed opposite the connector portion and has an inner diameter surface comprising a plurality of axial grooves. A tool receiver structured to receive at least a portion of a cutting tool is provided, the tool receiver having an outer diameter surface comprising a plurality of axial grooves. The tool receiver is mounted in the holder portion so as to align the axial grooves of the inner and outer diameter surfaces and define axial sleeves, wherein the axial sleeves are filled with dampening elements.
Embodiments described herein can be understood more readily by reference to the following detailed description and examples and their previous and following descriptions. Elements and apparatus described herein, however, are not limited to the specific embodiments presented in the detailed description. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations will be readily apparent to those of skill in the art without departing from the spirit and scope of the invention.
Referring now to
Tool holder bodies can have any shape or configuration not inconsistent with the objectives of the present invention. For example, a connector portion (210) of a tool holder body (200) can be structured or configured to engage a rotary machine in any manner. In some embodiments, as in
Similarly, the holder portion (220) can have any shape, architecture or configuration not inconsistent with the objectives of the present invention. In the embodiments illustrated in
A tool holder assembly described herein further comprises a tool receiver. Tool receivers (300) are structured to receive at least a portion of a cutting tool. In the embodiment of
A tool receiver (300) can be configured to lockingly engage or otherwise restrict motion of the cutting tool, such as by one or more radial locking pins (500). As illustrated in
The tool receiver (300) has an outer diameter surface (310) comprising a plurality of axial grooves (320) as illustrated in
The tool receiver (300) is configured to be mounted in the holder portion (220) so as to align the axial grooves (240) of the inner diameter surface (230) with the axial grooves (320) of the outer diameter surface (310) to define axial sleeves. Axial sleeves formed by axial grooves (240, 320) can have any desired cross-sectional shape. For example, in some cases, the axial sleeves have a circular or elliptical cross-sectional profile. In certain other embodiments, the axial sleeves have a polygonal cross-sectional profile.
In some cases, axial grooves (240) of the inner diameter surface (230) are of different cross-sectional profile than the axial grooves (320) of the outer diameter surface (310). For example, at least one axial groove can have a substantially semi-circular cross-section, with the opposing axial groove having a polygonal cross-section. In other cases, axial grooves (240, 320) of the inner and outer diameter surfaces (230, 310) are of the same cross-sectional profile. In one such embodiment, each axial groove forming the axial sleeve can have a semi-circular cross-sectional profile, resulting in a cylindrical axial sleeve.
In addition, the axial grooves (240) of the inner diameter surface (230) and the axial grooves (320) of the outer diameter surface (310) forming the axial sleeves can be arranged and/or oriented in any manner. The axial grooves (240, 320), in some embodiments, are parallel or substantially parallel with a central longitudinal axis (A-A) of the tool holder assembly. In certain other cases, the axial grooves (240) of the inner diameter surface (230) and/or the axial grooves (320) of the outer diameter surface (310) are not parallel to the central longitudinal axis. Such an embodiment is illustrated in
In some embodiments, the number of axial grooves (320) on an outer diameter surface (310) can correspond to the number of axial grooves (240) on an inner diameter surface (230). In other embodiments, the number of axial grooves (320) on an outer diameter surface (310) differs from the number of axial grooves (240) on an inner diameter surface (230). Such an arrangement can permit selection of a number of axial sleeves to be utilized for a particular tool receiver (300), permitting interchangeability of different tool receivers (300) with a single tool holder (200).
Axial sleeves formed by aligned axial grooves are filled with dampening elements. Dampening elements (330) are illustrated in
Dampening elements can be encapsulated by, fastened to, and/or contained within axial sleeves in any manner or by any means not inconsistent with the objectives of the present invention. In some cases, dampening elements (330) are not mechanically fastened to the axial grooves (240, 320) of the outer diameter surface (310) or the inner diameter surface (230). In such embodiments, the dampening elements (330) can be held in position within the axial sleeves primarily or entirely by frictional fit or compression. In certain other embodiments, the dampening elements (330) may be fastened or connected to the axial sleeves by an adhesive.
In some configurations of a tool holder assembly (100) described herein, one or more of the inner diameter surface (230), outer diameter surface (310), and/or dampening elements (330) are sized, shaped, or otherwise configured such that the dampening elements (330) prevent contact of the tool receiver (300) and holder portion (220). For example, axial grooves (320) on the outer diameter surface (310) and/or axial grooves (240) on the inner diameter surface (230) can each define a cross-sectional size less than 50% of the cross-sectional size of the dampening elements (330), thereby permitting the dampening elements (330) to prevent surface contact of the tool receiver (300) and holder portion (220). While the above description provides one embodiment of a configuration wherein dampening elements prevent contact of the tool receiver and holder portion, it is to be understood that other configurations are also possible. In such configurations, dampening elements (330) can be operable to dampen vibrational, rotational, and/or axial forces induced during a rotational cutting operation.
In some cases, tool holder assemblies described herein can further comprise at least one secondary dampening element (340) disposed on or about the outer diameter surface (310). In some embodiments, a secondary dampening element can be circular or substantially circular, and can be disposed about the central longitudinal axis (A-A). Secondary dampening elements are, in some embodiments, operable to prevent contact of the tool receiver (300) and the connector portion (220) in at least an axial direction. In some cases, secondary dampening elements are operable to dampen vibrational, rotational, and/or axial forces induced during a rotational cutting operation.
In another aspect, methods of assembling a tool holder having a central longitudinal axis are described herein. A method described herein comprises providing a tool holder body having a connector portion and a holder portion. The connector portion is structured to engage a rotary machine, and the holder portion is disposed opposite the connector portion and has an inner diameter surface comprising a plurality of axial grooves. A tool receiver structured to receive at least a portion of a cutting tool is provided, the tool receiver having an outer diameter surface comprising a plurality of axial grooves. The tool receiver is mounted in the holder portion so as to align the axial grooves of the inner and outer diameter surfaces and define axial sleeves, wherein the axial sleeves are filled with dampening elements.
Any tool holder assembly can be used consistent with the above description in Section I. For example, axial grooves of the outer diameter surface and associated dampening elements can be parallel to the central longitudinal axis, as illustrated in
Individual steps of methods described herein can be carried out in any manner not inconsistent with the objectives of the present invention. In some embodiments, mounting the tool receiver in the holder portion can comprise filling the axial sleeves with dampening elements by positioning the dampening elements into the axial grooves of the outer diameter surface prior to mounting the tool receiver in the holder portion. In certain cases, the axial sleeves are filled with the dampening elements by positioning the dampening elements in the axial grooves of the inner diameter surface prior to mounting the tool receiver in the holder portion.
Various embodiments of the invention have been described in fulfillment of the various objects of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the invention.
