Alignment unit and assembly method

Abstract

The present invention relates to an alignment unit (2) for a medical instrument, the alignment unit (2) comprising a stator housing (4) capable of accommodating a drive unit, preferably in the form of a handpiece, a threaded bolt (14) having an external thread (18) for connection to the stator housing (4), and a carrier (30) having an internal thread (34) for connection to the stator housing (4), the external thread (18) of the bolt (14) and the internal thread (34) of the carrier (30) being formed in opposite directions, and the carrier (30) and the bolt (14) being fixed by rotational movements in opposite directions so that they abut each other axially. Furthermore, the present invention relates to a method of assembling the alignment unit (2).

Description

[Technical Field]

[0001] The present invention relates to an alignment unit for medical equipment, in particular handheld instruments. Furthermore, the present invention relates to a method for assembling an alignment unit. [Background technology]

[0002] In general medical devices, and particularly handheld instruments, it is often necessary to connect two shaft-like components (e.g., cylindrical, hollow shaft, hollow body, sleeve, tubular components, etc.) together, which can be easily achieved by a threaded connection.

[0003] One advantage of such a threaded connection is that the two connected parts can be infinitely adjusted relative to one another. This allows the two parts to be threaded (further screwed in) or unthreaded (loosened) relative to one another to a predetermined rotational position over the length of the threaded connection for circumferential alignment (radial alignment). Circumferential alignment (radial alignment) is particularly necessary when one of the two parts has a groove (e.g., an insertion groove) or a protrusion that must be positioned (aligned) in a specific circumferential position due to external installation space requirements.

[0004] At the same time, this is also a drawback of the above-mentioned threaded connection because, in order to tighten the threaded connection to a predetermined torque and prevent unintentional loosening, the threaded connection must abut against an opposing receiving portion in the axial direction. Typically, axial abutment is achieved by fully screwing one of the two parts to be connected until it abuts against the other part. However, when the two parts are fully screwed together, it becomes impossible to realign the two parts in the circumferential direction (radial alignment). Summary of the Invention

[0005] The present invention is based on the problem of alleviating or avoiding the drawbacks of the prior art. In particular, an alignment unit (alignment unit) and an assembly method for assembling such an alignment unit are provided, which are capable of simultaneously firmly connecting two parts to one another, in particular axially fixing them at any or indefinite axial position, and allowing circumferential alignment (radial alignment) relative to one another. Furthermore, the alignment unit should be compact, cost-effective and easy to assemble.

[0006] The underlying problem of the present invention is solved by an alignment unit for medical devices, in particular handheld instruments, having the features of claim 1 and by a method for assembling an alignment unit having the features of the independent claims. Advantageous further developments are the subject of the subclaims and will be explained in more detail below.

[0007] More precisely, the problem of the present invention is solved in particular by an alignment unit for a medical device (in particular a handheld instrument) comprising a stator housing, a threaded bolt, and a carrier. The drive unit, preferably in the form of an (electric) handpiece, can be accommodated in the stator housing. Preferably, the stator housing may have a (distal) substantially tubular end. The threaded bolt comprises an external thread connecting the bolt to the stator housing (in particular to the internal thread of the stator housing). Preferably, the threaded bolt comprises a (proximal) substantially tubular end, the external thread being formed on the outer circumferential surface of which. The external thread of the threaded bolt may be screwed into the end of the stator housing. The carrier comprises an internal thread connecting the carrier to the stator housing (in particular to the external thread of the stator housing). Preferably, the carrier comprises a (proximal) substantially tubular end, the internal thread being formed on the inner circumferential surface of which which. The internal thread of the carrier may be screwed into the end of the stator housing.

[0008] In other words, the alignment unit includes a stator housing, a threaded bolt, and a carrier, and both the threaded bolt and the carrier are threaded from the proximal side through their respective threaded connections and attached to the stator housing (particularly, the distal end of the stator housing). In this case, it is preferable that the threaded bolt is attached to the inside (inner peripheral surface) of the stator housing, and the carrier is attached to the outside (outer peripheral surface) of the stator housing. Alternatively, the threaded bolt may be attached to the outside of the stator housing, and the carrier may be attached to the inside of the stator housing. In other words, the threaded connections of the threaded bolt and the carrier are complementary (i.e., one is formed on the inside and the other is formed on the outside), but are not threaded together, but are threaded into the corresponding threaded connections of the stator housing.

[0009] According to the present invention, the external thread of the threaded bolt and the internal thread of the carrier are configured with opposite threads. This means, for example, that the threaded bolt is configured with a right-hand thread and the carrier is configured with a left-hand thread, or that the threaded bolt is configured with a left-hand thread and the carrier is configured with a right-hand thread. The threaded bolt and the carrier are fixed by counter-rotational movements (movements in opposite directions) so that the carrier and the threaded bolt abut against each other axially (in particular, so that they tighten against each other). This has the advantage that, since the threaded bolt must be turned in a different direction from the carrier to loosen it, the frictional moment generated by the axial abutment between the threaded bolt and the carrier can counteract unintentional loosening of the two threaded connections. At the same time, the axial position where the threaded bolt and the carrier abut against each other is not fixed at the threaded end but can be set to the desired position (required position) by the screw-in depth of the two threaded connections, allowing for stepless adjustment over the length of the threaded connection, thereby leaving the possibility of circumferential alignment (radial alignment).

[0010] The object of the present invention is therefore achieved in particular by the fact that both the threaded bolt and the carrier are screwed into the stator housing via a respective threaded connection (thread), and that the threads (external thread) of the threaded bolt and the threads (internal thread) of the carrier are configured opposite to each other, so that the carrier and the threaded bolt are fixed (can be fixed) by counter-rotational movements (movements in opposite directions) such that they abut (particularly clamp) against each other in the axial direction (at their stop surfaces). As a result, the threaded bolt and the carrier can be axially fixed by clamping, without their axial position being fixed (for example, determined by the threaded end) and without their rotational alignment being fixed.

[0011] Preferably, the threaded portion (female threaded portion) of the stator housing into which the threaded bolt is screwed and the threaded portion (male threaded portion) of the stator housing into which the carrier is screwed may be formed at least partially in the same axial portion of the stator housing. This means that a specific tubular portion (end) of the stator housing is screwed on the outside (outer circumferential surface) into one part (e.g., the carrier) and on the inside (inner circumferential surface) into the other part (e.g., the threaded bolt). In other words, the threaded connection between the stator housing and the threaded bolt and the threaded connection between the stator housing and the carrier are at least partially (preferably over the entire axial (longitudinal) length of at least one (or both) of the threaded connections) radially nested. In other words, the stator housing, the threaded bolt, and the carrier are at least partially radially nested, and the threaded connection is at least partially, preferably completely, located in the radially nested region.

[0012] Preferably, the threaded connection between the stator housing and the threaded bolt and the threaded connection between the stator housing and the carrier have different diameters (nominal sizes), which allows for radial nesting.

[0013] According to a preferred embodiment, a first axial gap may be formed between the stator housing and the threaded bolt. This means, in particular, that the threaded bolt is not screwed completely into the stator housing, but is prevented from further screwing by its axial abutment with the stator housing. This maintains the adjustability of the threaded bolt for radial alignment in both directions of rotation.

[0014] According to a preferred embodiment, a second axial gap may be formed between the carrier and the stator housing. This means, in particular, that the carrier is not completely screwed into the stator housing, but that further screwing is prevented by the axial abutment of the carrier with the stator housing. This maintains the adjustability of the circumferential alignment (radial alignment) in both directions of rotation for the carrier as well.

[0015] According to a further development of the preferred embodiment, the alignment unit may include an outer housing. The stator housing may be accommodated within the outer housing. Furthermore, the outer housing may be configured to cover a second axial gap between the carrier and the stator housing. This avoids disadvantages arising from a second axial gap formed on the outer peripheral surface (for example, the possibility of external contaminants entering the outer housing or the stator housing).

[0016] According to a preferred embodiment, the threaded bolt may have a tool engagement feature (tool engagement structure) that fits the shape of a tool for introducing torque via the first socket wrench, and the tool engagement feature may in particular have a hexagonal inner profile, preferably on the inside (inner peripheral surface), which allows the threaded bolt to be screwed into the stator housing from the outside, for example using the first socket wrench, without disassembling the alignment unit.

[0017] According to a preferred embodiment, the carrier may be provided with a tool engagement feature (tool engagement structure) that fits onto the shape of a tool to introduce torque via a second socket wrench, preferably formed on the outer periphery of the carrier, which allows the carrier to be screwed into the stator housing from the outside using, for example, a second socket wrench, without the need to disassemble the alignment unit.

[0018] According to a preferred embodiment, the alignment unit may comprise a threaded sleeve formed separately from the stator housing. The threaded sleeve is fixedly connected to the stator housing, in particular in a rotationally and axially fixed manner. The threaded sleeve may comprise an internal thread, via which the external thread of the threaded bolt is connected to the stator housing. This means that the stator housing and the threaded bolt are indirectly fixed via the threaded sleeve, which is designed as a separate insert and firmly connected to the stator housing. This has the advantage that the threaded connection between the stator housing and the threaded bolt can be produced particularly cost-effectively, since the internal thread can be provided on a pre-fabricated sleeve rather than directly on the stator housing, which may be difficult to machine or access.

[0019] According to a further development of the preferred embodiment, the threaded sleeve may have at least one radially projecting protrusion (in particular a protrusion projecting radially outward or a protrusion projecting radially inward). For example, the threaded sleeve may have two protrusions located opposite each other in the circumferential direction. The protrusions may engage with the stator housing (in particular a corresponding recess in the stator housing) for a rotationally and / or axially fixed fit-fit connection with the stator housing. This has the advantage that a strong connection between the threaded sleeve, which is designed as a standard part (general-purpose part), and the stator housing can be achieved in a particularly simple manner. Furthermore, in this way, a suitable material combination for the threaded connection can be selected independently of the material selected for the stator housing.

[0020] According to another embodiment, the stator housing may have an internal thread integrally formed on its inner surface, through which the external thread of the threaded bolt is connected to the stator housing. That is, the internal thread may be formed directly and integrally on the stator housing. This is particularly advantageous when installation space is very limited and a separate insert cannot be used.

[0021] According to a preferred embodiment, the alignment unit may comprise a rotor shaft that can be torque-transmittingly connected to the drive unit. For example, via a torque-transmitting connection to the rotatable rotor shaft, rotation of the rotor shaft can be directly converted into rotation of a tool of the handheld instrument or indirectly converted into a corresponding movement (e.g., angulation) of the tool. The rotor shaft may partially axially extend (protrude) into the threaded bolt, particularly in a specific axial region. In particular, the rotor shaft may partially axially extend into an axial region in which an external thread or a tool engagement feature of the threaded bolt is formed. The rotor shaft may have, on its outer (outer periphery) surface, particularly in said axial region, a tool engagement feature (tool engagement structure), particularly having a hexagonal profile, for introducing torque via a socket wrench (preferably a first socket wrench). That is, the tool engagement feature of the rotor shaft and the tool engagement feature of the threaded bolt are preferably arranged radially nested within each other. These tool engagement features can then be rotated (if necessary simultaneously) with the same socket wrench due to corresponding features of the socket wrench, with the advantage that circumferential alignment (radial alignment) between the rotor shaft and the threaded bolt and rotational fixation of both parts can be achieved simultaneously via said socket wrench.

[0022] According to a further development of the preferred embodiment, the rotor shaft may be provided with a funnel-shaped tapered outlet of the tool engagement geometry, i.e., the tool engagement geometry is connected to the rotor shaft contour via a number of (e.g., six) radially chamfered surfaces (inclined surfaces). This has the advantage of facilitating the attachment of a socket wrench. Furthermore, this ensures automatic alignment of the rotor shaft with the socket wrench, which allows the socket wrench to be used even in areas of the rotor shaft that are difficult to see due to the internal arrangement.

[0023] According to a further development of the preferred embodiment, the rotor shaft (particularly its distal end) may have an internal thread for receiving an axial fixing element (axial locking element), which can be screwed into the internal thread of the rotor shaft. For example, the axial fixing element may be formed as a threaded sleeve having a threaded shape (particularly a hexagonal internal shape) on its inner (inner circumferential surface) part. A torque can be applied to the rotor shaft via a first socket wrench, so that once the axial fixing element is screwed into the internal thread of the rotor shaft, the rotor shaft can be held in place using the first socket wrench. This fixes the rotor shaft against external rotation, and the axial fixing element (preferably the axial fixing element axially fixing the hexagonal insert) can be replaced without disassembling the alignment unit. This facilitates the replacement of parts that are subject to wear (e.g., the hexagonal insert) in the rotor shaft.

[0024] According to a preferred embodiment, the alignment unit may include a first socket wrench for applying torque to the tool engagement profile of the threaded bolt and for applying torque to the tool engagement profile of the rotor shaft. The first socket wrench may have a hollow cylindrical (hollow body) engaging portion. The outer (outer circumferential surface) of the engaging portion of the first socket wrench is formed with a first opposing portion having a hexagonal outer shape that is complementary to the tool engagement profile of the threaded bolt. The inner (inner circumferential surface) of the engaging portion of the first socket wrench is formed with a second opposing portion having a hexagonal inner shape that is complementary to the tool engagement profile of the rotor shaft. This allows the first socket wrench to be used for applying torque to the threaded bolt and the rotor shaft, and for holding the rotor shaft in place.

[0025] According to a further development of the preferred embodiment, the first and second opposing parts may preferably have the same shape (in particular both hexagonal) and in particular may have the same circumferential orientation (radial alignment), which has the advantage that the engaging part of the first socket wrench can be made with a relatively thin wall thickness, thereby saving space and allowing it to be inserted into a small radial gap between the rotor shaft and the threaded bolt.

[0026] According to a further development of the preferred embodiment, the first socket wrench may include an axial stop surface. The axial stop surface may be arranged such that when the axial stop surface abuts against the threaded bolt or the rotor shaft in the axial direction, i.e., when the first socket wrench is in a socket engagement state (fully inserted), the first opposing portion engages with a tool engagement profile on the threaded bolt and the second opposing portion engages with a tool engagement profile on the rotor shaft. This limits the insertion depth of the first socket wrench. At the same time, when the first socket wrench is fully inserted, a rotational coupling between the rotor shaft and the threaded bolt is reliably achieved via the first socket wrench, thereby easily securing (holding) the rotor shaft and the threaded bolt and simultaneously allowing torque to be introduced.

[0027] The object of the present invention is also solved by a medical device, in particular a handheld instrument, which is provided with said alignment unit.

[0028] The object of the present invention is further achieved by an assembly method for assembling the alignment unit. In the assembly method, in a first step, a threaded bolt is screwed into a stator housing until the threaded bolt abuts against the stator housing in the axial direction. In a second step, a carrier is screwed into the stator housing until the carrier abuts against the threaded bolt in the axial direction. In a third step, the carrier is unscrewed (loosened) from the stator housing until a predetermined circumferential alignment (radial alignment) of the carrier with respect to the stator housing is completed. In a fourth step, the threaded bolt is unscrewed (loosened) from the stator housing until the threaded bolt abuts against the carrier in the axial direction. In a fifth step, the carrier and the threaded bolt are rotated (twisted) in opposite rotational directions.

[0029] According to a preferred embodiment of the assembly method, in a step preceding the first step, a threaded sleeve is inserted into the stator housing in a non-rotatable and axially fixed manner, and in the first step, a threaded bolt is screwed into the threaded sleeve to secure it to the stator housing.

[0030] According to a preferred embodiment of the assembly method, in the fourth step, a predetermined angular offset (e.g., 10 degrees) from the predetermined circumferential positioning (radial alignment) may be maintained, for example, by an auxiliary means (auxiliary tool). As a result, the predetermined angular offset can be corrected again by rotating (twisting) in the opposite direction during locking (i.e., applying a predetermined tightening torque). Then, from the fifth step onwards, the predetermined circumferential positioning (radial alignment) is accurately provided.

[0031] In other words, the present invention relates to an alignment unit for circumferentially aligning a carrier with respect to a stator housing. In this case, a screw is used to provide infinitely variable adjustment. The threaded connection is externally adjustable, eliminating the need for disassembly. A left-handed thread is used to prevent loosening. In particular, a threaded sleeve may be inserted into the stator housing in a non-rotatable manner, for example, by using two lateral projections. A threaded bolt may then be fully threaded into the threaded sleeve. The carrier may then be fully threaded into the stator housing until an axial stop surface is reached on the threaded bolt. When circumferentially aligning the carrier, particularly if the circumferential insertion groove is not in the desired position, the carrier may be unscrewed (loosened) until the desired carrier alignment is achieved. The threaded bolt is then threaded distally until it reaches the axial stop surface on the carrier. This creates a gap (axial clearance) between the carrier and the stator housing, which may be covered by the outer housing. Final fixation may be performed by counter-rotating (i.e., locking) the threaded bolts and the carrier.

[0032] Preferably, a torque is introduced into the threaded bolt with a hex wrench and then counteracted on the carrier with an external socket wrench. This allows slight twisting during tightening to be compensated for by maintaining the angle accordingly. For example, a predefined 10-degree twist is achieved by an auxiliary means (auxiliary tool), which compensates for the 0-degree position when the predetermined torque is reached.

[0033] Furthermore, the alignment unit may be used for quick-change functions of hexagonal inserts housed in the rotor shaft. In this case, the rotor shaft may be secured against rotation by two hexagons (i.e., an inner hexagon of the threaded bolt and an outer hexagon of the rotor shaft), allowing the hexagonal insert to be replaced without disassembling the handpiece, alignment unit, and instrument. In this case, the hexagonal shape (structure) of the hexagonal insert serves to transmit torque from the rotor shaft to the tool of the instrument, and is preferably configured as a separate insert part. This separate insert part, which is prone to wear, can be easily replaced by inserting a socket wrench into the alignment unit and then into the rotor shaft to secure the rotor shaft. The hexagonal insert is typically secured axially by a threaded sleeve with a hex socket, which can be loosened through the hex socket while the rotor shaft is held firmly in place. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a cross-sectional view taken along the longitudinal direction of an alignment unit according to the present invention in a completed assembled state. [Figure 2] 1 shows an alignment unit at various points in an assembly process according to the present invention; [Figure 3] 1 shows an alignment unit at various points in an assembly process according to the present invention; [Figure 4] 1 shows an alignment unit at various points in an assembly process according to the present invention; [Figure 5] 1 shows an alignment unit at various points in an assembly process according to the present invention; [Figure 6] 1 shows an alignment unit at various points in an assembly process according to the present invention; [Figure 7] FIG. 10 shows an alignment unit and a socket wrench for applying torque to the bolts of the alignment unit and the rotor shaft. DETAILED DESCRIPTION OF THE INVENTION

[0035] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[0036] FIG. 1 shows an alignment unit 2 for medical equipment, in particular handheld instruments, according to the present invention in a fully assembled state.

[0037] The alignment unit 2 comprises a stator housing 4. In particular, the stator housing 4 forms the proximal component of the medical instrument. A drive unit, preferably in the form of an (electric or motor-driven) handpiece (not shown), can be housed within the stator housing 4. The stator housing 4 defines a cavity for housing the drive unit and other components of the medical instrument. At its distal end, the stator housing 4 has a substantially tubular end portion 6. The outer periphery of the end portion 6 of the stator housing 4 is provided with an external thread 8. The inner periphery of the end portion 6 of the stator housing 4 is fitted with a threaded sleeve 10 formed separately from the stator housing 4. The sleeve 10 is formed with an internal thread 12.

[0038] The alignment unit 2 includes a threaded bolt 14. The bolt 14 is disposed distally of the stator housing 4. The bolt 14 is hollow and has a central passage. The bolt 14 has a substantially tubular end 16 at its proximal end. The proximal end 16 of the bolt 14 has an external thread 18 on its outer periphery. The external thread 18 of the bolt 14 is formed to be complementary to the internal thread 12 of the sleeve 10. The bolt 14 threads into the stator housing 4 via the external thread 18 and is screwed into the stator housing 4. The bolt 14 has a substantially tubular end 20 at its distal end. The distal end 20 of the bolt 14 has a tool engagement feature 22 on its inner side. Torque can be introduced into the bolt 14 from the distal side via the tool engagement feature 22. The tool engagement feature 22 has a hexagonal inner shape. The bolt 14 has a protrusion 24 that protrudes radially outward. In the illustrated embodiment, the protrusion 24 has the shape of a circumferential flange. The protrusion 24 is formed with a first axial stop surface 26 facing distally (the side axially away from the stator housing 4). The protrusion 24 is formed with a second axial stop surface 28 facing proximally (the side axially facing the stator housing 4). In a fully assembled state (finished state), a first axial clearance (first axial gap) is formed between the second axial stop surface 28 and the stator housing 4 and the sleeve 10. That is, the bolt 14 is not threaded completely into the sleeve 10 (until it abuts against the sleeve 10).

[0039] The alignment unit 2 includes a carrier 30. The carrier 30 is disposed distally of the stator housing 4. The carrier 30 is hollow and has a central passage. At its proximal end, the carrier 30 has a substantially tubular end 32. The inner circumferential surface of the proximal end 32 of the carrier 30 is provided with an internal thread 34. The internal thread 34 of the carrier 30 is formed to be complementary to the external thread 8 of the stator housing 4. The carrier 30 is threaded into the stator housing 4 via the internal thread 34. The carrier 30 has a tool engagement shape (not explicitly shown) on its outer circumferential surface, through which torque can be introduced (from the outside) into the carrier 30. Distal to the internal thread 34, the carrier 30 is tapered by a radial step, which forms an axial abutment surface (axial stop surface) 36. In the assembled state, the axial abutment surface 36 contacts the first axial stop surface 26 of the bolt 14. In the fully assembled state, a second axial clearance (second axial gap) is formed between the proximal end 32 of the carrier 30 and the stator housing 4. That is, the carrier 30 is not fully screwed into the stator housing 4 (until it stops due to the abutment). The carrier 30 has an insertion groove 38. The insertion groove 38 is formed in the peripheral wall of the carrier 30 (for example, as a through hole) and extends in the axial direction of the carrier 30. In the assembled state of the alignment unit 2, the insertion groove 38 is located at a predetermined position (circumferential position, i.e., rotational position) (in the illustrated embodiment, the insertion groove 38 is located at the bottom position, i.e., the 0° position).

[0040] Preferably, the alignment unit 2 may include an outer housing 40. The stator housing 4 is disposed within the outer housing 40. The outer housing 40 is configured to cover the second axial gap between the carrier 30 and the stator housing 4.

[0041] According to the present invention, the external threads 18 of the bolt 14 and the internal threads 34 of the carrier 30 are formed in opposite directions. That is, the bolt 14 and the carrier 30 must be rotated in different directions to thread forward or backward. Furthermore, the bolt 14 and the carrier 30 are locked together by counter-rotation, so that the carrier 30 and the bolt 14 are axially tightened relative to each other.

[0042] A method for assembling the alignment unit 2 will be described below.

[0043] As shown in Figure 2, in a previous step of the assembly process, a threaded sleeve 10 is inserted into the stator housing 4. The sleeve 10 has two protrusions 42 that protrude radially outward. The protrusions 42 engage with corresponding recesses in the stator housing 4. This connects the sleeve 10 to the stator housing 4 in a rotationally fixed and axially fixed manner.

[0044] As shown in Figure 3, in the first step of the assembly method, the threaded bolt 14 is threaded into the stator housing 4 (specifically, into the threaded sleeve 10). The bolt 14 is fully threaded into the stator housing 4, i.e., until it makes axial contact with the stator housing 4 (and the sleeve 10). Torque is introduced into the bolt 14, particularly via the tool-engaging features 22, which have a hexagonal internal shape.

[0045] 4, in a second step of the assembly method, the carrier 30 is screwed onto the stator housing 4. The carrier 30 is screwed completely into the stator housing 4, that is, until the axial abutment surface 36 contacts the first axial stop surface 26. Torque is introduced into the carrier 30, particularly via tool engagement features (not explicitly shown) on the exterior of the carrier 30.

[0046] When the carrier 30 is fully screwed in, the insertion grooves 38 of the carrier 30 are usually not aligned in the desired circumferential direction (radial alignment) (see FIG. 5). In this case, in the third step of the assembly method, the carrier 30 is unscrewed from the stator housing 4 (the carrier 30 is loosened from the stator housing 4). This unscrewing of the carrier 30 is continued until the desired circumferential positioning (radial alignment) of the carrier 30 (particularly the insertion grooves 38) with respect to the stator housing 4 is completed (see FIG. 1). Subsequently, in the fourth step of the assembly method, the bolts 14 are unscrewed from the stator housing 4 (the bolts 14 are loosened from the stator housing 4). This unscrewing of the bolts 14 is continued until the first axial stop surfaces 26 of the bolts 14 axially contact the axial abutment surfaces of the carrier 30 (see FIGS. 6 and 1).

[0047] In the fifth step of the assembly method, the carrier 30 and the bolt 14 are rotated (twisted) in opposite directions to lock them together, thereby tightening and fixing the carrier 30 and the bolt 14 to each other with a predetermined torque.

[0048] In this case, slight twisting during tightening (locking) may be corrected by using an auxiliary tool, for example, to hold the angle properly, thereby compensating for the angle when a predetermined torque is reached.

[0049] According to another aspect of the present invention, the alignment unit 2 includes a rotor shaft 44 connectable to the drive unit so as to be able to transmit torque (see FIGS. 7 to 9). The rotor shaft 44 partially extends (projects) in the axial direction into the bolt 14. In particular, the rotor shaft 44 extends (projects) into the axial region in which the male thread portion 18 of the bolt 14 or the tool engagement shape 22 of the bolt 14 is formed.

[0050] For example, via a torque transmission connection to the rotatably driven rotor shaft 44, rotation of the rotor shaft 44 can be directly converted into rotation of a tool (not shown) of a medical device (handheld instrument) or indirectly converted into a coordinated movement (e.g., angling) of the tool.

[0051] For this purpose, a hexagonal insert 46 is received in the rotor shaft 44 in a rotationally fixed manner, via which the rotation of the rotor shaft 44 can be further transmitted. The hexagonal insert 46 is configured as an insert part with a hexagonal inner shape for torque transmission. To axially fix the hexagonal insert 46, a locking element in the form of a threaded sleeve 48 is received in the rotor shaft 44. The locking element (sleeve 48) abuts against the hexagonal insert 46 in the axial direction, thereby preventing the hexagonal insert 46 from falling out of the rotor shaft 44.

[0052] The threaded sleeve 48 has external threads on its outer periphery that screw into a corresponding internal thread on the inside of the rotor shaft 44. The sleeve 48 has a hex socket 50 for applying torque to the sleeve 48.

[0053] The rotor shaft 44 has a tool engagement structure 52 on its outer circumferential surface, particularly having a hexagonal outer shape, for introducing torque. The tool engagement structure 52 is provided particularly in a region that axially projects into the bolt 14. The rotor shaft 44 preferably has a funnel-shaped tapered end 54 of the tool engagement structure 52. The tapered end 54 may be formed, for example, with a plurality of (e.g., six) inclined surfaces that are radially arranged corresponding to the hexagonal outer shape.

[0054] The alignment unit 2 further includes a socket wrench 56. The socket wrench 56 serves to apply torque to the tool engagement geometry 22 of the threaded bolt 14 and to apply torque to the tool engagement geometry 52 of the rotor shaft 44. The socket wrench 56 has a hollow cylindrical (hollow body) engagement portion 58. A first opposing portion 60, particularly having a hexagonal outer shape, is formed on the outer circumferential surface of the engagement portion 58. The first opposing portion 60 is complementary to the tool engagement geometry 22 of the bolt 14. A second opposing portion 62, particularly having a hexagonal inner shape, is formed on the inner circumferential surface of the engagement portion 58. The second opposing portion 62 is complementary to the tool engagement geometry 52 of the rotor shaft 44.

[0055] Preferably, the first and second opposing portions 60 and 62 may have the same shape, in particular, both may be hexagonal, and in particular may be formed to have the same radial arrangement. Furthermore, the socket wrench 56 has an axial stop surface 64. Specifically, the axial stop surface 64 is provided so that when the axial stop surface 64 abuts the bolt 14 in the axial direction, i.e., when the bolt 14 is fully inserted, the first opposing portion 60 engages with the inner hexagonal portion (tool engagement shape 22) of the bolt 14, and the second opposing portion 62 engages with the outer hexagonal portion (tool engagement shape 52) of the rotor shaft 44 (see FIG. 7). [Explanation of symbols]

[0056] 2 Alignment Unit 4 Stator housing 6 tubular ends 8 Male thread 10 Threaded sleeve 12 Female thread 14 Threaded bolts 16 Tubular end 18 Male thread 20 tubular end 22 Tool engagement shape portion 24 Protrusion 26 First axial stop surface 28 Second axial stop surface 30 Career 32 Tubular end 34 Female thread 36 Axial contact surface 38 Insertion groove 40 outer housing 42 Protrusion 44 rotor shaft 46 hexagonal insert 48 Threaded sleeve 50 hex socket 52 Tool engagement shape portion 54 Funnel-shaped tapered end 56 First Socket Wrench 58 Hollow engagement part 60 First opposing part 62 Second opposing part 64 Axial stop surface

Claims

1. An alignment unit (2), in particular for handheld medical instruments, comprising: a stator housing (4) capable of accommodating a drive unit, preferably in the form of a handpiece; a threaded bolt (14) having an external thread (18) for connection to the stator housing (4); a carrier (30) having an internal thread (34) for connection to the stator housing (4); the male thread portion (18) of the bolt (14) and the female thread portion (34) of the carrier (30) are formed in opposite directions to each other, and the carrier (30) and the bolt (14) are fixed so as to come into contact with each other in the axial direction by rotational movements in opposite directions to each other. Alignment unit.

2. A first axial gap is formed between the stator housing (4) and the bolt (14).

2. The alignment unit according to claim 1, wherein:

3. A second axial gap is formed between the carrier (30) and the stator housing (4), The alignment unit (2) comprises an outer housing (40) that accommodates the stator housing (4); The outer housing (40) is configured to cover the second axial gap between the carrier (30) and the stator housing (4).

3. The alignment unit according to claim 1 or 2.

4. the bolt (14) comprises a tool engagement feature (22), preferably hexagonal, formed inside the bolt (14) for introducing a torque via a first socket wrench (56); and / or The carrier (30) preferably includes a tool-engaging feature formed on the exterior of the carrier (30) for introducing torque via a second socket wrench.

4. The alignment unit according to claim 1, wherein the alignment unit is a unit for aligning a substrate.

5. The alignment unit (2) includes a threaded sleeve (10) formed separately from the stator housing (4) and coupled to the stator housing (4); The sleeve (10) has a female thread portion (12) formed therein, The male thread portion (18) of the bolt (14) is connected to the stator housing (4) via the female thread portion (12).

5. The alignment unit according to claim 1, wherein the alignment unit comprises: a first electrode;

6. The sleeve (10) has at least one radially protruding protrusion (42); the protrusions (42) engage with the stator housing (4), in particular in corresponding recesses in the stator housing (4), for coupling therewith such that they are fixed against rotation in a fitted manner and / or are fixed axially to the stator housing (4); 6. The alignment unit according to claim 5, wherein:

7. The alignment unit (2) comprises a rotor shaft (44) that is torque-transmittably connectable to the drive unit; The rotor shaft (44) partially projects into the bolt (14) in the axial direction; the rotor shaft (44) is provided on its exterior with a tool engagement feature (52), in particular a hexagonal shape, for introducing torque via a socket wrench, such as the first socket wrench (56); 7. The alignment unit according to claim 1, wherein the alignment unit is a unit for aligning a substrate.

8. the rotor shaft (44) has a funnel-shaped tapered end (54) of the tool engagement feature (52); 8. The alignment unit according to claim 7, wherein:

9. the alignment unit (2) comprises a first socket wrench (56) for introducing torque into the tool engagement shape (22) of the bolt (14) and for introducing torque into the tool engagement shape (52) of the rotor shaft (44); The first socket wrench (56) has a hollow engaging portion (58), A first opposing portion (60), particularly a hexagonal portion, is formed on the outside of the engagement portion (58) and is complementary to the tool engagement shape portion (22) of the bolt (14); a second opposing portion (62), particularly a hexagonal portion, complementary to the tool engagement shape portion (52) of the rotor shaft (44) is formed inside the engagement portion (58); 9. The alignment unit according to claim 7 or 8.

10. 10. An assembly method for assembling an alignment unit (2) for a medical device according to any one of claims 1 to 9, comprising: The bolt (14) is threaded into the stator housing (4) in the axial direction until the bolt (14) contacts the stator housing (4); The carrier (30) is threaded into the stator housing (4) in the axial direction until the carrier (30) contacts the bolt (14); The carrier (30) is unscrewed from the stator housing (4) until the circumferential alignment of the carrier (30) with respect to the stator housing (4) is completed; The bolt (14) is unscrewed from the stator housing (4) until the bolt (14) contacts the carrier (30) in the axial direction; The carrier (30) and the bolt (14) are rotated in opposite directions. An assembly method characterized by:

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