Thread former

Abstract

A thread former (10) defining a longitudinal axis (AA), a first end (20) and a second end (30) axially remote from the first end (20), the thread former (10) comprising: a shank (40) located at the first end (20) and adapted for attachment to a tool holder; and an elongated working area (50) located at the second end (30), comprising: at least one thread (60) distributed helically around the working area (50); a plurality of longitudinally extending linear grooves (70) arranged about the longitudinal axis (AA), the linear grooves (70) intersecting the at least one helical thread (60); and a plurality of cams (61) formed by the intersection point (63) of the linear grooves (70) with the at least one thread (60), wherein cams (61) which are adjacent around the working area (50) with respect to a circumferential direction differ in the profile type and / or the profile dimension, wherein in a first of the adjacent cams (61) all thread sections are defined by a first profile type and / or a first profile dimension, wherein in a second of the adjacent cams (61) all thread sections are defined by a second profile type and / or a second profile dimension which differs from the first profile type and / or the first profile dimension.

Description

Field of the invention

[0001] The present invention relates to thread cutting tools and, more particularly, to thread formers for use in cold working applications. background

[0002] Thread forming tools and the tools that use them are well known. Thread forming tools enable the formation of internal threads in a workpiece by applying compressive force to the internal surfaces. Furthermore, thread forming tools can achieve high-quality surface thread formation without generating chips and can produce stronger internal threads with improved accuracy than comparable cutting tools. Thread forming tools and associated thread forming tools can also offer improved tool life, reduced fracture susceptibility, and reduced machine downtime compared to equivalent cutting tools.

[0003] Forming threads can be used with a variety of materials, especially materials with relatively low tensile strength such as aluminum, copper, brass, zinc, and low-carbon steel. Forming threads can also be used to form internal threads, both through and blind threads. As the demand for thread-forming applications continues to grow, new thread cutting and forming thread designs must overcome the limitations of previous designs and styles.

[0004] US 3 661 471 A, GB 1 090 875 A, and DE 198 34 039 A1 each describe thread cutters. DE 10 2005 051 174 A1 describes a circular thread former. AT 231 246 B describes a thread spinning mandrel. Summary

[0005] In one aspect, thread formers are described herein that have a plurality of lobes arranged on a helical thread, wherein adjacent lobes differ in profile type and / or profile dimension. For example, a thread-forming drill bit described herein (hereinafter "forming thread former" or "tap") defines a longitudinal axis, a first end, and a second end axially remote from the first end. A shank is located at the first end and is suitable for mounting in a tool holder. An elongated working area is located at the second end, the working area including at least one helical thread and a plurality of longitudinally extending linear grooves. The longitudinally extending linear grooves intersect the helical thread and form a plurality of lobes, wherein adjacent lobes differ from one another in profile type and / or profile dimension.

[0006] According to another aspect, a thread former described herein defines a longitudinal axis, a first end, and a second end axially remote from the first end. A shank is located at the first end and is adapted for mounting in a tool holder. An elongated working area is located at the second end, the working area including at least one helical thread and a plurality of lobes located on the at least one helical thread about the longitudinal axis. Adjacent lobes differ in profile type and / or profile dimension.

[0007] According to another aspect, thread formers are described herein. A thread forming tool includes a tool holder and a thread former attached to the tool holder. The thread former defines a longitudinal axis, a first end, and a second end axially remote from the first end. A shank is located at the first end and engages the tool holder, and an elongated working portion is located at the second end. The elongated working portion consists of at least one thread extending helically around the working portion and a plurality of longitudinally extending linear grooves intersecting the helical thread. The intersection between the linear grooves and the helical thread forms a plurality of lobes, with adjacent lobes differing from one another in profile type and / or profile dimension. Brief description of the drawings Fig. 1 illustrates a perspective view of a thread former according to an embodiment described herein. Fig. 2 illustrates a perspective view and schematic partial sectional view of the working area of ​​a thread former according to an embodiment described herein. Fig. 3 illustrates a schematic sectional view of a thread former according to an embodiment described here. Fig. 4 illustrates the schematic view of Fig. 3 with a representation of different radial profile dimensions according to embodiments described here. Fig. 5A and Fig. 5B illustrate sectional views of thread formers according to embodiments described herein. Detailed description

[0008] Embodiments described herein will be more readily understood from the following detailed description and examples, and from the preceding and following descriptions thereof. However, elements and devices described herein are not limited to the specific embodiments shown in the detailed description. It should be understood that these embodiments merely illustrate the principles of the present invention. Numerous modifications and adaptations will be readily apparent to those skilled in the art without departing from the spirit and scope of the invention.

[0009] With reference to the Fig. 1-3, there is illustrated, according to an embodiment described herein, a thread former, which is generally designated by reference numeral 10. As shown in the Fig. 1 and Fig. 2, the thread former (10) defines a longitudinal axis (AA), a first end (20), and a second end (30) located axially remote from the first end (20). The thread former (10) comprises a shank (40) located at the first end (20) and suitable for receipt in a tool holder (not shown), and an elongated working portion (50) located at the second end (30). The elongated working portion (50) includes at least one thread, generally (60), that extends helically around the working portion (50) and may include a plurality of longitudinally extending linear grooves (70) along the longitudinal axis (AA). The linear grooves (70) intersect the helical thread, thereby forming a plurality of lobes (61). Adjacent lobes (61) differ in profile type and / or profile dimension.

[0010] The linear grooves and the plurality of lobes can be arranged or configured in any orientation that does not conflict with the objectives of the present invention. For example, in some cases, a thread former may have no longitudinally extending linear grooves, one linear groove, or multiple linear grooves. In embodiments that include a plurality of longitudinally extending linear grooves, these grooves may be arranged generally axially symmetrically about the longitudinal axis. In other cases, the linear grooves are arranged asymmetrically about the longitudinal axis. The lobes can be individually selected to have a zero profile (fully concentric lobe), a con-eccentric profile, or an eccentric profile. As one skilled in the art will appreciate, a con-eccentric profile is a combination of a concentric and eccentric profile.For example, in some embodiments, a first third of the land has a concentric edge, while the remaining two-thirds of the land has an eccentric profile. Furthermore, cams with an eccentric profile can have the same or different profile dimensions.

[0011] For the purposes of the present disclosure and as set forth in Fig. 3, profile types are described relative to a virtual circle (80) defined by the outermost edges of the thread (60) in a helical cross-section of the working area (50). The term "zero profile" is used herein for a cam that is fully concentric with and / or cocircular with the virtual circle. The term "con-eccentric profile" is used herein for a profile that includes a portion slightly less than the entire profile that is concentric with and / or cocircular with the virtual circle. This portion is a "concentric edge," as the term is used herein. Portions of the cutting land that do not lie within the concentric edge are eccentric portions. The concentric edges described herein may form an angle θ1, as in Fig. 3. The angle θ1 can have any value that does not conflict with the objectives of the present invention. For example, a value of θ1 can be selected from Table 1. Table I - Value of θ1 (degrees) 0-10 0,5-10 1-10 2-10 4-10 0-6 0-8 3-7

[0012] An "eccentric profile" indicates a profile that does not contain any lines or arcs that are concentric with and / or cocircular with the virtual circle. Lobes having an eccentric profile may have any shape or form that does not conflict with the objectives of the present invention. For example, the eccentric profile may include a vertex (63). The vertex (63) of an eccentric profile may include a single point that intersects or touches the virtual circle, or a vertex may include a curved portion that is neither concentric with nor cocircular with the virtual circle. Lobes (61) containing an eccentric profile and / or an eccentric portion define a "profile dimension," or a curved shape in a radial direction against the longitudinal axis away from the vertex along the circumference of the thread. Fig. Figure 4 shows different non-restrictive profile dimensions of eccentric profiles as described here.

[0013] In some cases, adjacent cams (61) define an alternating pattern of profile type and / or profile dimension. For example, in the embodiment of the Fig. 3 Cams with con-eccentric profiles and cams with eccentric profiles. In such cases, the cams with a con-eccentric profile can define cutting lands with a concentric edge (62) centrally therefrom, and cams with an eccentric profile can define vertices (63) centrally therefrom. In certain other embodiments, adjacent cams form an alternating pattern of first eccentric profiles with a first eccentric profile dimension and second eccentric profiles with a second eccentric profile dimension, wherein the first and second profile dimensions differ.

[0014] Thread formers (10) as described here can, seen in cross section as shown in Fig. 3, any plurality of lobes (61) that does not conflict with the objectives of the present invention. In some cases, the thread formers (10) described herein may include an even plurality of lobes (61). For example, the cross-section may include at least 4 lobes (61), at least 6 lobes (61), or at least 8 lobes (61). In certain other cases, the thread formers (10) described herein may include an odd plurality of lobes (61). For example, the cross-section may include at least 5 lobes (61), at least 7 lobes (61), or at least 9 lobes (61). Thread formers may further include a plurality of linear grooves (70) corresponding to the plurality of lobes (61). For example, a cross-section having 6 lobes (61) may also include 6 grooves (70).

[0015] As in the Fig. 5A and Fig. 5B, thread formers (10) may further comprise at least one coolant or lubricant channel (90). The coolant channel (90) may have any configuration that does not conflict with the objectives of the present invention. In some cases, the coolant channel (90), as shown in Fig. 5A, completely collinear with the longitudinal axis (AA) and terminates in at least one axial coolant hole (91) at the second end (30) of the thread former (10). In certain other cases, as in Fig.5B, the coolant channel (90) is collinear with the longitudinal axis (AA) over a major portion of its length and terminates in at least two radial coolant bores (92) in at least two of the linear grooves (70). In some embodiments, a thread former (10) may include a plurality of coolant bores (not shown) that run parallel to the longitudinal axis (AA) and terminate in one or more axial or radial bores along the second end or in a plurality of radial grooves.

[0016] The working area (50) of a thread former (10) described herein may have any suitable external or peripheral shape or configuration. For example, in some cases, the helical thread (60) may form a shoulder taper at the second end (30). Any desired shoulder taper configuration may be employed. For example, the helical thread (60) may have a shoulder taper with a length (measured in thread pitches) as shown in Table II: Table II - Length of taper (in threads) 1-10 1-1,5 2,5-3 3-5 5-8 8-10

[0017] A thread pitch is the distance from one point on a thread to an adjacent, corresponding point on the thread in the axial direction, measured parallel to the longitudinal axis. Lobes (61) located within a shoulder taper on the thread former (10) described here can have a corresponding profile type and / or a corresponding profile dimension to the non-tapered lobes located remote from the second end (30). In some cases, lobes (61) located within a shoulder taper on the thread former (10) described here can have a different profile type and / or profile dimension compared to the non-tapered lobes located remote from the second end (30).

[0018] According to another aspect, tapping tools are described herein. A tapping tool comprises a tool holder and a thread former attached to the tool holder. The thread former defines a longitudinal axis, a first end, and a second end axially remote from the first end. A shank is located at the first end and engages the tool holder, and an elongated working portion is located at the second end. The elongated working portion includes at least one thread extending helically around the working portion and a plurality of longitudinally extending linear flutes intersecting the helical thread. The intersection between the linear flutes and the helical thread forms a plurality of lobes, with adjacent lobes differing from one another in profile type and / or profile dimension.For example, the lobes of the thread former described here can be independently selected as zero profile, con-eccentric profile, or eccentric profile. Furthermore, lobes with an eccentric profile can have the same or different profile dimensions. Furthermore, the thread former of the forming tool can have any design and / or properties as previously described.

[0019] Various embodiments of the invention have been described which achieve the various objects of the invention.

Claims

[1] A thread former (10) defining a longitudinal axis (AA), a first end (20) and a second end (30) axially remote from the first end (20), the thread former (10) comprising: a shank (40) located at the first end (20) and adapted for attachment to a tool holder; and an elongated working area (50) located at the second end (30), comprising: at least one thread (60) distributed helically around the working area (50); a plurality of longitudinally extending linear grooves (70) arranged about the longitudinal axis (AA), the linear grooves (70) intersecting the at least one helical thread (60); and a plurality of cams (61) formed by the intersection point (63) of the linear grooves (70) with the at least one thread (60), wherein cams (61) which are adjacent around the working area (50) with respect to a circumferential direction differ in the profile type and / or the profile dimension, wherein in a first of the adjacent cams (61) all thread sections are defined by a first profile type and / or a first profile dimension, wherein in a second of the adjacent cams (61) all thread sections are defined by a second profile type and / or a second profile dimension which differs from the first profile type and / or the first profile dimension. [2] Thread former (10) according to claim 1, wherein the profile type is selected from the group consisting of zero profile, con-eccentric profile and eccentric profile. [3] Thread former (10) according to claim 1, wherein adjacent lobes (61) define an alternating pattern of lobes (61) with a con-eccentric profile and lobes (61) with an eccentric profile, the con-eccentric profile defining cutting lands with a concentric edge (62) central thereto and the eccentric profile defining vertices (63) central thereto. [4] Thread former (10) according to claim 3, wherein the concentric edge (62) forms an angle (θ1) in the range of about 0.5° to about 10°. [5] Thread former (10) according to claim 3, wherein a cross-section helically laid over the thread (60) defines a virtual circle (80), and wherein concentric edges (62) are cocircular with the virtual circle (80) and the vertices (63) intersect the virtual circle (80). [6] Thread former (10) according to claim 1, wherein adjacent cams (61) differ in profile dimension. [7] Thread former (10) according to claim 6, wherein adjacent cams (61) also differ in the type of profile. [8] Thread former (10) according to claim 6, wherein adjacent cams (61) form an alternating pattern of first eccentric profiles having a first eccentric profile dimension and second eccentric profiles having a second eccentric profile dimension, wherein the first and second profile dimensions differ. [9] Thread former (10) according to claim 1, wherein a cross-section placed helically over the thread (60) comprises a straight plurality of cams (61). [10] Thread former (10) according to claim 9, wherein the cross section comprises at least 4 cams (61). [11] Thread former (10) according to claim 9, wherein the cross section comprises at least 6 cams (61). [12] Thread former (10) according to claim 9, wherein the cross section comprises at least 8 cams (61). [13] Thread former (10) according to claim 1, further comprising at least one coolant channel which is collinear with the longitudinal axis (AA) and terminates in at least one axial coolant bore (91) at the second end (30). [14] Thread former (10) according to claim 1, further comprising at least one coolant channel which is collinear with the longitudinal axis (AA) and terminates in at least two radial coolant bores (91) in at least two of the straight grooves (61). [15] Thread former (10) according to claim 1, wherein the at least one helical thread (60) defines a shoulder taper at the second end (30). [16] Thread former (10) according to claim 15, wherein the neck taper is about 1 to about 10 threads long. [17] Thread former (10) according to claim 15, wherein the neck taper is about 3 to about 5 threads long. [18] The thread former (10) of claim 1, wherein the plurality of grooves (70) are arranged generally axially symmetrically about the longitudinal axis (AA). [19] A thread former (10) defining a longitudinal axis (AA), a first end (20) and a second end (30) axially remote from the first end (20), the thread former (10) comprising: a shank (40) located at the first end (20) and adapted for attachment to a tool holder; and an elongated working area (50) located at the second end (30), comprising: at least one thread (60) distributed helically around the working area (50); and a plurality of cams (61) distributed on the at least one thread (60) around the longitudinal axis (AA), wherein cams (61) which are adjacent around the working area (50) with respect to a circumferential direction differ in the profile type and / or the profile dimension, wherein in a first of the adjacent cams (61) all thread sections are defined by a first profile type and / or a first profile dimension, wherein in a second of the adjacent cams (61) all thread sections are defined by a second profile type and / or a second profile dimension which differs from the first profile type and / or the first profile dimension. [20] The thread former (10) of claim 19, wherein the elongated working portion (50) further comprises at least one longitudinally extending linear groove (70) intersecting the at least one helical thread (60). [21] Thread forming tool, comprising: a tool holder adapted to receive a thread former (10); and a thread former (10) attached to the tool holder and defining a longitudinal axis (AA), a first end (20) and a second end (30) axially remote from the first end (20), the thread former (10) comprising: a shank (40) located at the first end (20) and adapted for attachment to the tool holder; and a working area (50) located at the second end (30), comprising: at least one thread (60) arranged helically around the working area (50); a plurality of longitudinally extending linear grooves (70) located about the longitudinal axis (AA), the linear grooves (70) intersecting the at least one thread (60); and a plurality of cams (61) formed by the intersection of the linear grooves (70) with the at least one thread (60), wherein cams (61) which are adjacent around the working area (50) with respect to a circumferential direction differ in the profile type and / or the profile dimension, wherein in a first of the adjacent cams (61) all thread sections are defined by a first profile type and / or a first profile dimension, wherein in a second of the adjacent cams all thread sections are defined by a second profile type and / or a second profile dimension which differs from the first profile type and / or the first profile dimension. [22] Thread forming tool according to claim 21, wherein the profile type is selected from the group consisting of zero profile, con-eccentric profile and eccentric profile. [23] Thread forming tool according to claim 21, wherein adjacent cams (61) define an alternating pattern of cams (61) with con-eccentric profile and cams (61) with eccentric profile.

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