MODULAR DRILL HEAD WITH FINE ADJUSTMENT CLICK MECHANISM

Abstract

Modular drill head (2), comprising: a tubular main body (12) having an internal thread (32) with a first inclination and a pair of axially extending, projecting elements (42, 44); a movable rod (16) which engages with the tubular main body (12) such that the movable rod (16) moves in an axial direction D with respect to the tubular main body (12), wherein the movable rod (16) has an internal thread (34) with a second inclination which differs from the first inclination; and a leadscrew (14) arranged within the tubular main body (12), which has a first external thread (36), a second external thread (38) and a plurality of teeth, wherein the first external thread (36) engages cooperatively with the internal thread (32) of the tubular main body (12) and the second external thread (38) engages cooperatively with the internal thread (34) of the movable rod (16), wherein the rotation of the leadscrew (14) causes the pair of axially extending, cantilevered elements (42, 44) of the tubular main body (12) to engage cooperatively with the plurality of toothings of the leadscrew (14) in a manner that produces an audible and tactile click, each click indicating a distance by which the movable rod (16) is displaced relative to the tubular main body (12), furthermore, a rotation lock is provided which prevents rotation of the movable rod (16). wherein the anti-rotation device comprises at least one cylindrical pin (18) which is arranged in the movable rod (16) by an interference fit and is located in an elongated slot formed in the tubular main body (12), characterized in that the at least one cylindrical pin (18) contacts a spring contained in a housing in the tubular main body (12), which provides a preload force in the axial direction to eliminate the play between the internal thread (32) of the tubular main body (12) and the internal thread (34) of the movable rod (16) and the first and second external threads (38) of the leadscrew (14).

Description

AREA OF REVELATION

[0001] In general, the disclosure relates to cutting tools for performing machining operations on a workpiece. In particular, the disclosure relates to a modular drill head that provides reliable adjustment of the cutting diameter by means of a fine-adjustment click mechanism. BACKGROUND OF THE REVELATION

[0002] As is generally known, drilling is a mechanical process for machining surfaces, carried out by rotating one or more cutting tools. Drilling machines used to perform these operations typically allow the mounting of various types of tools to enable other operations, such as drilling, milling, tapping, and the like.

[0003] Depending on the position of the shaft / spindle, these drilling machines can be horizontal or vertical, and drilling can be cylindrical, conical, radial, or spherical, thus enabling the machining of conical or cylindrical internal surfaces in areas that are normally difficult to access. This drilling process, achieved by positioning the machining tool by adjusting the headstock to a specific height and the platen in a transverse position, allows for perfectly parallel axes, with all displacements indicated on a graduated scale by optical readers or analog / digital counters.

[0004] Therefore, drilling tools are used for these drilling operations, selected according to the dimensions and characteristics of the operation (i.e., length and diameter). The tools are typically small in size, as they operate within bores previously created by drill bits, such as a boring bar. This boring bar, in turn, must be rigid, cylindrical, and free of straightness errors to ensure correct positioning on the shaft / spindle for mounting bearing bushings, thus preventing potential deflections and vibrations.

[0005] These boring bars accommodate replaceable tips and micrometric adjustment systems for increasing the machined diameter to compensate for tip wear and thus enable better statistical control of the process. These adjustment systems can include drill heads that allow for precise drilling within tolerance requirements.

[0006] However, conventional drill heads do not offer sufficient precision and allow for a coarse adjustment (i.e., the resolution of the device allows increments of 0.010 mm in relation to the radius).

[0007] Another disadvantage is the fact that conventional drill heads require tools for setting the measurement, which increases the setup time.

[0008] Another disadvantage is that conventional drill heads have a locking screw, which renders the device unusable if an untrained technician damages the adjustment mechanism during operation. The locking screw also complicates adjustment, as the cutting diameter changes when the operator tightens the screw.

[0009] Therefore, it would be desirable to provide a drill head for use in a modular drill rod that solves the problems mentioned above.

[0010] From DE 10 2011 015 835 A1 a drill head with the features of the preamble of claim 1 can be seen. SUMMARY OF THE REVELATION

[0011] The problem of providing an improved drill head with a fine-adjustment click mechanism is solved by the features of independent claims 1 and 11. A tubular main body is provided with a pair of axially extending, cantilevered elements that cooperatively engage with the teeth of a leadscrew to provide an audible and tactile click, each click indicating a distance by which the movable rod is displaced relative to the tubular main body.

[0012] In one aspect, a modular drill head comprises a tubular main body having an internal thread with a first inclination and a pair of axially extending, cantilevered elements. The modular drill head further comprises a movable rod engaging with the tubular main body, such that the movable rod moves in an axial direction, D, with respect to the tubular main body. The movable rod has an internal thread with a second inclination that differs from the first inclination. The modular drill head further comprises a leadscrew arranged within the tubular main body, which has a first external thread, a second external thread, and teeth. The first external thread cooperatively engages with the internal thread of the tubular main body, and the second external thread cooperatively engages with the internal thread of the movable rod.The rotation of the leadscrew causes the pair of axially extending, cantilevered elements of the tubular main body to engage cooperatively with the multitude of teeth of the leadscrew in a manner that produces an audible and tactile clicking sound, each click indicating a distance by which the movable rod is displaced in relation to the tubular main body. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] While various embodiments of the disclosure are illustrated, the specific embodiments shown should not be interpreted as limiting the claims. It is understood that various changes and modifications can be made without deviating from the scope of this disclosure. Fig. Figure 1 is an isometric view of a modular drill head according to an embodiment of the disclosure; Fig. Figure 2 is an isometric view of the modular drill head of Fig. 1, where the main tube body has been omitted for the sake of clarity; Fig. Figure 3 is a side view of the modular drill head of Fig. 1; Fig. Figure 4 is a top view of the modular drill head of Fig. 1; Fig. Figure 5 is a cross-sectional view of the modular drill head along line 5-5 of Fig. 4; Fig. Figure 6 is an isometric bottom view of the lead screw according to one embodiment of the disclosure; Fig. Figure 7 is a cross-sectional view of the movable rod according to one embodiment of the disclosure; Fig. Figure 8 is an isometric bottom view of the tubular main body according to one embodiment of the disclosure; Fig. Figure 9 is an enlarged view of the anti-rotation device for the movable rod, which has a slot and a cylindrical pin of the modular drill head. Fig. 1 includes; Fig. Figure 10 is an enlarged plan view of a geometric feather shape according to an aspect of the revelation; Fig. 11 is an enlarged plan view of another geometric feather shape according to another aspect of the revelation; and Fig. Figure 12 is a bottom view of the modular drill head of Fig. 1, which represents the interaction between the projecting elements and the lead screw according to one aspect of the revelation. DETAILED DESCRIPTION OF THE REVELATION

[0014] The directional terms used here, for example left, right, front, back, top, bottom, and derivatives thereof, refer to the orientation of the elements shown in the drawings and do not limit the claims unless expressly stated therein. Identical parts are identified by the same reference number in all drawings.

[0015] The approximation language used throughout this patent and its claims may be applied to modify any quantitative representation that could permissibly vary without altering the fundamental function to which it relates. Accordingly, a value modified by a term or terms such as "about," "approximately," and "essentially" is not intended to be limited to the exact value stated. At least in some cases, the approximation language may correspond to the precision of an instrument used to measure the value. Here, and throughout this patent and its claims, range boundaries may be combined and / or interchanged, and such ranges are identified and include all subranges contained therein unless context or language indicates otherwise.

[0016] Throughout the text and claims, the use of the word "approximately" in relation to a range of values ​​(e.g., "approximately 22 to 35 wt.%) is intended to modify both the stated high and low values ​​and reflects the penumbra of variation associated with measurement, significant places, and interchangeability, all as understood by an average professional to whom this disclosure applies.

[0017] For the purposes of this patent specification (except in the operational examples), unless otherwise stated, all numbers expressing quantities and ranges of components, process conditions, etc., are to be understood in all cases as modified by the term "approximately". Accordingly, the numerical parameters specified in this description and the appended claims are approximations that may vary depending on the desired results to be obtained with the present disclosure. At the very least, and not as an attempt to limit the application of the equivalence doctrine to the scope of the claims, each numerical parameter should be interpreted at least in light of the number of significant figures indicated and by applying ordinary rounding techniques.As used in this description and the attached claims, the singular forms “ein”, “eine” and “der / die / das” shall furthermore include the plural forms, unless they are expressly and unambiguously limited to one form.

[0018] Notwithstanding the fact that the numerical ranges and parameters that define the broad scope of the disclosure are approximations, the numerical values ​​presented in the specific examples are reported as precisely as possible. However, every numerical value inherently contains certain errors that necessarily result from the standard deviation observed in the respective corresponding test measurements, including those observed in the measuring instrument. It is also understood that each numerical range listed herein is intended to encompass all subranges summarized therein. For example, a range of "1 to 10" is intended to encompass all subranges in between, including the listed minimum value of 1 and the listed maximum value of 10, i.e., a range with a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.Since the disclosed numerical ranges are continuous, they encompass every value between the minimum and maximum values. Unless expressly stated otherwise, the various numerical ranges specified in this application are approximations.

[0019] In the following patent specification and claims, reference is made to a number of terms which have the following meanings.

[0020] The singular forms “ein”, “eine” and “der / die / das” include the plural unless the context clearly indicates otherwise.

[0021] “Optional” means that the event or circumstance described below may or may not occur, and that the description includes cases in which the event occurs and cases in which it does not.

[0022] As used herein, a “leadscrew”, also known as a drive spindle or transmission spindle, is a spindle used to translate a rotary motion into a linear motion.

[0023] As used herein, a “gear” is a rotating, circular machine part having milled teeth or, in the case of a pinion gear or gear, inserted teeth (called pinions) that mesh with another compatible toothed part.

[0024] With reference to the Fig. Figure 1-5 shows a modular drill head 10 according to an embodiment of the disclosure. In general, the modular drill head 10 comprises a tubular main body 12, which is usually made of steel, and a leadscrew 14 arranged in the tubular main body 12, which is also usually made of steel. Fig. In Figure 2, the tubular main body 12 is omitted to allow for better visualization of the leadscrew 14. The drill head 10 also includes a movable rod 16, usually made of steel, which moves in an axial direction (i.e., parallel to the z-axis) relative to the tubular main body 12. Cylindrical pins 18 are press-fitted into the movable rod 16. The pins 18 are also guided in axially extended slots 20 in the tubular main body 12 to act as an anti-rotation device and prevent the rotation of the movable rod 16, but allow movement of the movable rod 16 by a distance in the axial direction D, which is defined by the slots 20 in the Fig. The arrows shown in Figures 1-3 and 5 indicate the following. Threaded fasteners 22, such as bolts, are used to attach the steel body 12 to a tool holder (not shown). A mounting screw 24 is used to clamp a cutting insert 26 in a plate seat 28 of the movable rod 16.

[0025] The axial adjustment of the movable rod 16 and the cutting insert 26 by a distance in the axial direction (i.e., parallel to the z-axis) is achieved by rotating the leadscrew 14 using a tool, such as an Allen key, which engages in a hexagonal recess 30 located at one end of the leadscrew 14. As shown in the Fig. 7 and Fig. As shown in Figure 8, the tubular main body 12 and the movable rod 16 have internal threads 32 and 34 respectively with different inclinations. As shown in the Fig. As shown in Figures 5-7, the lead screw 14 has external threads 36, 38 which engage cooperatively with the internal thread 32 of the tubular main body 12 and the internal thread 34 of the movable rod 16, respectively, as shown in the Fig. 5 and Fig. Figure 6 shows the embodiment shown. In the illustrated embodiment, the external threads 36 of the lead screw 14, which cooperate in engagement with the internal thread 32 of the tubular main body 12, have a larger diameter than the external threads 38 of the lead screw 14, which cooperate in engagement with the internal thread 34 of the movable rod 16.

[0026] One or more pins 18 prevent the rotation of the movable rod 16 and allow the movable rod 16 to move in an axial direction D (i.e., parallel to the z-axis) by a distance corresponding to the difference in the inclinations of the threads 36 and 38. For example, if the leadscrew 14 is rotated one full revolution (360°) and the difference in inclination is approximately 0.05 mm, the movable rod 16 will move approximately 0.05 mm in the axial direction.

[0027] As in Fig. As shown in Figure 9, the pins 18 are also in contact with springs 40, which can be 3D printed with the tubular main body 12. Each spring 40 is contained in a housing 41 within the tubular main body 12. The springs 40 provide a preload force in the axial direction and are important to eliminate the play between the internal thread 32 of the tubular main body 12 and the internal thread 34 of the movable rod 16, as well as the first and second external threads 36, 38 of the leadscrew 14, thus ensuring precise axial adjustment of the drill head 10. To increase the stiffness of the springs 40, they can be formed with various non-circular geometric shapes, such as elliptical, elongated, and the like, as shown in the Fig. 10 and Fig. 11 shown.

[0028] The modular drill head 10 has a click mechanism that provides the operator with audible and tactile feedback during fine adjustment of the modular drill head 10. In particular, the tubular main body 12 has a pair of axially extending, cantilevered elements 42, 44 which are arranged in a corresponding axially extending slot 43, 45 and engage with the teeth 46 of the leadscrew 14, as shown in Fig. As shown in Figure 12, the cantilevered elements 42 and 44 are in cooperative engagement. It should be noted that the cantilevered elements 42 and 44 are not exactly diametrically opposed to each other (i.e., by 180°), but are offset from each other by an angle A of approximately 7.2°. In the illustrated embodiment, the leadscrew 14 has a total of twenty-five teeth 46. The teeth 46 are therefore spaced apart from each other at an inclination P of approximately 14.4° (360° / 25 = 14.4°). Since the cantilevered elements 42 and 44 are offset from each other by the angle A of approximately 7.2°, one cantilevered element 44 is in engagement with one of the teeth 46, while the other cantilevered element 42 is not in engagement with any of the teeth 46. The accuracy of the rotation is therefore 360° / (2×25) = 7.2°, which is not possible with conventional trial-and-error methods.

[0029] The engagement of the projecting elements 42, 44 with the teeth 46 provides a defined stop for the rotation of the leadscrew 14. Therefore, the operator can control the rotation of the leadscrew 14 by feeling the engagement and disengagement of the teeth 46 from the projecting elements 42, 44. Furthermore, as already explained, a complete rotation of the leadscrew 14 corresponds to 0.05 mm. A rotation of the leadscrew 14 by approximately 7.2° results in a displacement of approximately 0.001 mm in the axial direction, D. It is evident that the invention is not limited by the number of teeth 46 and that the invention can be implemented with any desired number of teeth 46, depending on the quality of the acoustic and tactile feedback provided by the click mechanism.

[0030] It should be noted that the body 12 has two contact surfaces 48, 50 which can be ground to keep the distance d between these contact surfaces 48, 50 and the top of the cutting insert 26 constant, as shown in Fig. 3 shown. This is particularly useful to compensate for the manufacturing tolerances of the plate seat 28 during the manufacturing process of the modular drill head 10.

[0031] A finite element analysis (FEA) of the effects of loads on the cantilevered elements 42 and 44 was performed. The results show that the loads on the cantilevered elements 42 and 44 were very low, indicating that the cantilevered elements 42 and 44 are functioning well.

[0032] The modular drill head 10 of the disclosure offers several technical advantages compared to conventional drill heads. One advantage is that the modular drill head 10 of the disclosure has relatively fewer components, which contributes to cost reduction. Another technical advantage is that the modular drill head 10 of the disclosure provides a way to eliminate thread backlash even in a very small body, which is important for achieving a precision of 1 µm. A further technical advantage is that the modular drill head 10 offers excellent control over the tool setting through a click mechanism that also functions in a very small drill head. Finally, the modular drill head 10 of the disclosure provides a way to utilize the full stroke even considering the small size of the tool and its manufacturing tolerances.

[0033] While the currently preferred embodiments have been described, the disclosure may be carried out differently within the scope of the appended claims. PARTS LIST 10 modular drill head 12 tubular main bodies 14 Lead screw 16 movable rods 18 cylindrical pins 20 slots 22 Threaded fastening element 24 Mounting screws 26 cutting insert 28 plate seat 30 Hexagonal recess 32 internal threads (tubular body) 34 internal threads (movable rod) 36 external threads (lead spindle) 38 external threads (leadscrew) 40 springs 41 cases 42 cantilevered element 43 slots 44 cantilevered element 45 slots 46 teeth 48 contact area 50 contact area

Claims

Modular drill head (2) comprising: a tubular main body (12) having an internal thread (32) with a first inclination and a pair of axially extending, cantilevered elements (42, 44); a movable rod (16) engaging with the tubular main body (12) such that the movable rod (16) moves in an axial direction D with respect to the tubular main body (12), the movable rod (16) having an internal thread (34) with a second inclination that differs from the first inclination; and a leadscrew (14) arranged within the tubular main body (12), which has a first external thread (36), a second external thread (38) and a plurality of teeth, wherein the first external thread (36) engages cooperatively with the internal thread (32) of the tubular main body (12) and the second external thread (38) engages cooperatively with the internal thread (34) of the movable rod (16),wherein the rotation of the leadscrew (14) causes the pair of axially extending, projecting elements (42, 44) of the tubular main body (12) to engage cooperatively with the plurality of teeth of the leadscrew (14) in such a way as to produce an audible and tactile click, each click indicating a distance by which the movable rod (16) is displaced relative to the tubular main body (12), wherein furthermore an anti-rotation device is provided which prevents rotation of the movable rod (16), wherein the anti-rotation device comprises at least one cylindrical pin (18) which is arranged in the movable rod (16) by an interference fit and is located in an elongated slot formed in the tubular main body (12), characterized in that the at least one cylindrical pin (18) contacts a spring contained in a housing in the tubular main body (12),which provides a preload force in the axial direction to eliminate the play between the internal thread (32) of the tubular main body (12) and the internal thread (34) of the movable rod (16) and the first and second external threads (38) of the leadscrew (14). Modular drill head (2) according to claim 1, wherein the pair of axially extending cantilevered elements (42, 44) are not diametrically opposed to each other. Modular drill head (2) according to claim 2, wherein the pair of axially extending cantilevered elements (42, 44) is offset from each other by an angle A of about 7.2°. Modular drill head (2) according to claim 1, wherein the lead screw (14) has twenty-five teeth and the teeth are spaced apart from each other at an inclination P of about 14.4°. Modular drill head (2) according to claim 1, wherein the spring is 3D printed and has a non-circular geometric shape. Modular drill head (2) according to claim 1, wherein the spring is 3D printed and has an elliptical or elongated geometric shape. Modular drill head (2) according to claim 1, wherein the distance by which the movable rod (16) is displaced depends on the difference in inclination between the internal thread (32) of the tubular main body (12) and the internal thread (34) of the movable rod (16). Modular drill head (2) according to claim 1, wherein the first external thread (36) of the lead screw (14), which engages cooperatively with the internal thread (32) of the tubular main body (12), has a larger diameter than the second external thread (38) of the lead screw (14), which engages cooperatively with the internal thread (34) of the movable rod (16). Modular drill head (2) according to claim 1, wherein the second inclination differs from the first inclination by about 0.05 mm and thereby causes the movable rod (16) to move by about 0.05 mm in the axial direction when the leadscrew (14) is rotated one full revolution. Modular drill head (2) according to claim 1, wherein a rotation of the lead screw (14) by about 7.2° results in a displacement by a distance in the axial direction, D, of about 0.001 mm. Modular drill head (2) comprising a tubular main body (12) having an internal thread (32) with a first inclination and a pair of axially extending, cantilevered elements (42, 44); a movable rod (16) engaging with the tubular main body (12) such that the movable rod (16) moves in an axial direction D with respect to the tubular main body (12), the movable rod (16) having an internal thread (34) with a second inclination that differs from the first inclination; and a leadscrew (14) arranged within the tubular main body (12), which has a first external thread (36), a second external thread (38) and a plurality of teeth, wherein the first external thread (36) engages cooperatively with the internal thread (32) of the tubular main body (12) and the second external thread (38) engages cooperatively with the internal thread (34) of the movable rod (16),wherein the rotation of the leadscrew (14) causes the pair of axially extending, projecting elements (42, 44) of the tubular main body (12) to engage cooperatively with the plurality of teeth of the leadscrew (14) in such a way as to produce an audible and tactile click, each click indicating a distance by which the movable rod (16) is displaced relative to the tubular main body (12), wherein at least one movable, cylindrical pin (18) in the movable rod (16) is guided in a slot (20) formed in the tubular main body (12) to prevent rotation of the movable rod (16), characterized in that the at least one pin (18) is in contact with a spring (40) which provides a preload force in the axial direction,to eliminate the play between the internal thread (32) of the tubular main body (12) and the internal thread (34) of the movable rod (16) as well as the first and second external threads (36, 38) of the leadscrew (14). Modular drill head (2) according to claim 11, wherein the pair of axially extending cantilevered elements (42, 44) are not diametrically opposed to each other. Modular drill head (2) according to claim 12, wherein the pair of axially extending cantilevered elements (42, 44) is offset from each other by an angle A of about 7.2°. Modular drill head (2) according to claim 11, wherein the lead screw (14) has twenty-five teeth and the teeth are spaced apart from each other at an inclination P of about 14.4°. Modular drill head (2) according to claim 11, wherein the spring is 3D printed and has a non-circular geometric shape. Modular drill head (2) according to claim 11, wherein the spring is 3D printed and has an elliptical or elongated geometric shape. Modular drill head (2) according to claim 11, wherein the distance by which the movable rod (16) is displaced depends on the difference in inclination between the internal thread (32) of the tubular main body (12) and the internal thread (34) of the movable rod (16). Modular drill head (2) according to claim 11, wherein the first external thread (36) of the lead screw (14), which engages cooperatively with the internal thread (32) of the tubular main body (12), has a larger diameter than the second external thread (38) of the lead screw (14), which engages cooperatively with the internal thread (34) of the movable rod (16). Modular drill head (2) according to claim 11, wherein the second inclination differs from the first inclination by about 0.05 mm and thereby causes the movable rod (16) to move by about 0.05 mm in the axial direction when the leadscrew (14) is rotated one full revolution. Modular drill head (2) according to claim 11, wherein a rotation of the lead screw (14) by about 7.2° results in a displacement by a distance in the axial direction, D, of about 0.001 mm.

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